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ABSTRACT Objective: This study aimed to evaluate occlusion development after premature loss or extraction of deciduous anterior teeth, by means of a prospective cohort study. Methods: Fifteen infants and children aged 1 to 5 years old were longitudinally assessed (with loss or extraction of deciduous anterior teeth [n = 9], and without tooth losses [n = 6]). Photographs and dental casts at the baseline and after 24 months of follow-up were performed. Dental casts were scanned, and linear measurements were made on the digitalized models (missing tooth space, arch perimeter, arch length, arch width, intercanine length and intercanine width). The t-test was used for groups comparisons (α = 0.05). Results: Individuals’ mean age at baseline was 2.93 (± 1.18) years. No statistically significant differences were observed in the missing tooth space in the group with tooth loss during the 24 months of follow-up (p > 0.05). Arch perimeter, arch length, arch width, intercanine length and intercanine width did not show differences between the groups (p > 0.05). Qualitative photographic evaluation revealed other changes in the dental arches and occlusion, such as exfoliation and eruption of deciduous teeth, eruption of permanent teeth, self-correction or establishment of malocclusion, among others. Conclusion: The results suggest that the premature loss of deciduous anterior teeth does not affect the perimeter, length and width of the dental arches; however, other alterations that lead to malocclusion could be established.

Objectives: This study aimed to develop and validate a robotic system capable of performing accurate and minimally invasive jawbone milling procedures in oral and maxillofacial surgery., Methods: The robotic hardware system mainly includes a UR5E arm (Universal Robots, Denmark) and the binocular positioning system (FusionTrack 250, Atracsys LLC, Switzerland). The robotic software (Dental Navi 3.0.0, Yakebot Technology Ltd., China) is capable of generating cutting tool paths based on three-dimensional shape description files, typically in the stereolithography format, and selected cutting tool parameters, as well as designing surgical accessories. Fully impacted supernumerary tooth models in the maxilla were fabricated using software and three-dimensional printing. Following the planning of a customized cavity to fully expose the tooth, maxillary bone milling was performed on both the robot and static guide groups (n = 8). After milling, all models underwent scanning for assessment., Results: In the experiment with fully buried supernumerary tooth models in the maxilla, the root mean square, translation error, over-removal rate, and maximum distance were significantly smaller in the robot group compared to the static guide group. Moreover, the overlap ratio and Dice coefficient were significantly greater in the robot group. No statistically significant differences were observed between the two groups in terms of the rotation error (P = 0.80) or under-removal rate (P = 0.92)., Conclusions: This study has developed a robotic system for milling individualized jawbone cavities in oral and maxillofacial surgery, and its accuracy has been preliminarily verified to meet clinical requirements., Clinical Significance: The robotic system can achieve precise, minimally invasive, individualized jawbone milling in a variety of oral and maxillofacial surgeries, including tooth autotransplantation, surgical reshaping for zygomatic fibrous dysplasia, removal of fully impacted supernumerary or impacted teeth, and endodontic microsurgery, among other relevant clinical applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Objectives: This study aimed to assess the influence of the location and distribution of short-span scans, serving as intermediate registration data, on the trueness of digitally transferring the maxillomandibular relationship in full-mouth rehabilitation., Methods: Maxillary and mandibular complete-arch preparation casts mounted on an articulator were scanned, with and without interim restorations, using an intraoral scanner. Four types of short-span scans-right anterior, left anterior, right posterior, and left posterior-were captured from maxillary and mandibular casts. Each scan comprised two prepared teeth and two crowned teeth arranged alternately. These short-span scans served as intermediate data and were cross-registered with complete-arch interim restorations and preparation casts to transfer the maxillomandibular relationship. Based on the number (1 or 2), location (anterior or posterior), and distribution (unilateral or bilateral) of short-span scans, they were categorized into six groups. Trueness was assessed by evaluating the mandibular 3-dimensional (3D), spatial distance, angle, and linear distance deviations between the test and reference scans., Results: Significant differences in the trueness of digital cross-mounting were observed among the six groups (P < .05). The group registering the bilateral posterior areas exhibited the smallest 3D, spatial distance, angle, and linear distance deviations, whereas the group registering one anterior area showed the largest deviations., Conclusion: The number, location, and distribution of the registered short-span scans significantly affected the trueness of transferring the maxillomandibular relationship. A posterior short-span scan had higher trueness than an anterior scan. The symmetrical distribution of the two registered larger short-span scans over the cross-arch enhanced the registration trueness., Clinical Significance: Digital cross-mounting in full-mouth rehabilitation using short-span scans enhances transfer accuracy, improves patient comfort, and increases chairside efficiency., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Objective: To evaluate the effect of intraoral scanners (IOSs) and implant libraries (ILs) on the trueness of digital impressions for the fabrication of implant-supported full-arch (FA) prostheses., Methods: A stone cast of an edentulous maxilla with 6 implant analogues and cylindrical scanbodies (IPD ProCam®, Matarò, Barcelona, Spain) was probed using a coordinate measuring machine to capture a reference model (RM). The cast was mounted on a mannequin and scanned with 3 different IOSs (iTERO Element 5D Plus®, Align Technologies, San José, CA, USA; IS 3800®, Dexis, Quackertown, PN, USA; and i-700®, Medit, Seoul, South Korea). Ten scans were performed by an experienced operator using each IOS, first capturing only the occlusal surfaces, then the buccal and finally the palatal surfaces (less than 45 s per scan). In each scan, the meshes of the SBs were replaced by the corresponding IL file, with and without increment, to obtain the best correction for the mesh growth. The positions of the SBs in each file were compared with those in the RM, to evaluate the linear and cross distances between them. The final outcome was the trueness of the different IOSs, evaluating the effect of using different ILs on the quality of the impressions., Results: Significant differences were found between the different IOS scans and the RM, and among the different IOSs, in the different segments. The correction of the mesh growth through incremental ILs did not affect the final trueness of the IOS scans., Conclusions: Different levels of trueness were found among the IOSs evaluated, in the different scan segments, but with the cylindrical SBs used herein, the correction of the mesh growth with incremental ILs did not affect the final quality of the digital impressions., Statement of Clinical Relevance: There are still errors with IOS in the FA impressions. IOS have an effect on the quality of the digital impressions, and apparently the library has not, with purely cylindrical SBs: further studies are needed to confirm this aspect., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Objectives: To investigate whether the scanning time, trueness and number of photos are influenced when augmented reality (AR) heads-up display (HUD) is utilized during the intraoral scan of fully dentate mandibular arches., Methods: A total of 10 patients (6 females and 4 males) were included. The mandibular arch of each patient was scanned twice using an intraoral scanner (Trios4 Pod IOS: 3Shape): one with and one without AR-HUD (ML2; Magic Leap). Further, alginate impression was taken, and the cast was digitized to acquire the reference model for trueness comparison (T310, Medit). The scan time and number of photos were recorded. Trueness was evaluated qualitatively and quantitatively using colored heat maps and RMSE values respectively. t-test was used to evaluate the difference in scan time, trueness, and number of photos between the two groups (α = .05)., Results: AR-assisted IOS resulted in significantly faster scan time (44 s) compared to the time consumed following conventional scan method without AR-HUD (63 s) (P = <0.001). The number of photos was also significantly less with AR-assisted IOS (836) compared to IOS using conventional technique without AR-HUD (1209) P = <0.001. No statistical difference was detected in RMSE between the test groups., Conclusions: Integration of AR technology with IOS process represents a promising potential to acquire digital impressions with reduced scan acquisition time and reduced images count while simultaneously maintaining the trueness of the acquired scans., Clinical Significance: Augmented Reality presents an emerging potential in Prosthodontics to acquire digital impressions with decreased number of images and acquisition time., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objectives: To digitally evaluate the trueness and fit of additively and subtractively manufactured fixed complete dentures in materials intended for definitive use., Methods: An edentulous maxillary model with implants at the left first molar, left canine, right canine, and right first molar site was digitized and a fixed complete denture was designed. This design was used to fabricate fixed dentures in an additively manufactured resin for definitive use (AM), a high-impact polymer composite (SM-CR), and a strength gradient zirconia (SM-ZR) (n = 10). Each fixed denture was digitized and the surface (overall, occlusal, except occlusal, and abutments), linear, and interimplant distance deviations were analyzed. The fit was assessed with the triple-scan protocol. Data were analyzed with Welch analysis of variance and Games-Howell tests (α = 0.05)., Results: SM-ZR led to lower overall deviations than AM, which had the highest occlusal and the lowest abutments deviations (P ≤ 0.007). SM-ZR had the lowest occlusal and SM-CR had the highest except occlusal deviations (P ≤ 0.002). AM mostly had higher linear and SM-CR mostly had higher interimplant distance deviations (P ≤ 0.043). AM led to the highest marginal gap at the left canine site, while SM-CR had the highest and SM-ZR had the lowest gaps at the right canine site (P ≤ 0.022)., Conclusions: SM-ZR dentures mostly had trueness and marginal fit similar to or better than the other groups. Tested fixed complete dentures were mostly smaller than the design file in terms of interimplant distances., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: This study aimed to assess the effect of the "cut-out rescan" strategy on the accuracy of intraoral digital scans from 25° convergent implants positioned at two distinct depths., Material and Methods: Two customized models were fabricated, each designated to receive two posterior converged implant fixtures: one at a depth of 1 mm and the other at a depth of 4 mm. Initially, the models were scanned as reference casts using a lab scanner. The test group was involved in scanning the 1-mm and 4-mm implant models using an intraoral scanner in the following order: (1) scanning the 1-mm (T1; n = 10) and (2) 4-mm (T4; n = 10) implant groups with scan bodies connected to both fixtures in each model; (3) cut-out rescan (COR) in the 1-mm (COR1; n = 10) and (4) 4-mm (COR4; n = 10) models, leading to 40 digital files in standard tessellation language format. The mean absolute deviation (MAD), in terms of trueness and precision, between the experimental and control scans was assessed through the alignment of their respective datasets using three-dimensional analysis software. Two-way analysis of variance (ANOVA) and Levene's tests were used to analyze the data., Results: The COR4 group exhibited the highest MAD, indicative of both trueness and precision (Mean ±SD: 55.659 ±34.802). In contrast, the T1 group demonstrated the lowest MAD (Mean ±SD: 43.225 ±19.237). However, the ANOVA analysis showed no significant influence of depth (P = 0.506) or type of scan (P = 0.442) on the MAD. Precision also did not differ significantly across groups (P = 0.071)., Conclusions: The cut-out rescan approach demonstrated an accuracy comparable to that of the one-time scan method., Clinical Significance: Digital intraoral scanning provides clinicians with a range of tools to navigate challenging conditions in which conventional methods may prove difficult, such as cases involving angled adjacent implants. In these scenarios, the cut-out rescan tool serves as a valuable resource, aiding clinicians in overcoming the challenges associated with impression-making owing to the convergence of placed implants., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The surgery-first approach (SFA) orthognathic surgery can be beneficial due to reduced overall treatment time and earlier profile improvement. The objective of this study was to utilize deep learning to predict the treatment modality of SFA or the orthodontics-first approach (OFA) in orthognathic surgery patients and assess its clinical accuracy. A supervised deep learning model using three convolutional neural networks (CNNs) was trained based on lateral cephalograms and occlusal views of 3D dental model scans from 228 skeletal Class III malocclusion patients (114 treated by SFA and 114 by OFA). An ablation study of five groups (lateral cephalogram only, mandible image only, maxilla image only, maxilla and mandible images, and all data combined) was conducted to assess the influence of each input type. The results showed the average validation accuracy, precision, recall, F1 score, and AUROC for the five folds were 0.978, 0.980, 0.980, 0.980, and 0.998 ; the average testing results for the five folds were 0.906, 0.986, 0.828, 0.892, and 0.952. The lateral cephalogram only group had the least accuracy, while the maxilla image only group had the best accuracy. Deep learning provides a novel method for an accelerated workflow, automated assisted decision-making, and personalized treatment planning., Competing Interests: Competing interests None., (Copyright © 2024 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Although intraoral scanning is highly reliable, little is known about its accuracy in young children with limited mouth-opening ability., Aim: To determine the accuracy of intraoral scans based on the degree of mouth opening., Design: To simulate mouth opening in children with primary dentition, three groups (n = 5 per group) were allocated by maximum mouth opening of 30, 37 and 40 mm. After the primary dentition model was connected to a dental phantom, intraoral scanning was performed using iTero and TRIOS4. The scanned files were digitally evaluated. Root mean square values were calculated to assess trueness and precision., Results: iTero showed deviations of three-dimensional trueness of 0.067 ± 0.008, 0.063 ± 0.001 and 0.065 ± 0.005 mm, and TRIOS4 of 0.07 ± 0.002, 0.064 ± 0.003 and 0.066 ± 0.002 mm in the 30, 37 and 40 mm groups, respectively. There were no significant differences in either mouth opening (p > .017) or the intraoral scanners (p > .05). The same statistical results were obtained for precision, with the exception of the 30 mm of mouth opening., Conclusions: Within the limits of this study, limited mouth opening hardly influenced the accuracy of intraoral scanning., (© 2024 The Authors. International Journal of Paediatric Dentistry published by BSPD, IAPD and John Wiley & Sons Ltd.)

Objectives: To evaluate the effects of repeated cut-off and rescan procedures on the trueness of three intraoral scanners (IOS)., Methods: A tooth model (#16) with a standard class II cavity was prepared, and the complete-arch was scanned using a laboratory scanner (D2000, 3Shape A/S) to obtain a reference scan. Then the typodont was scanned with three IOSs (3Shape TRIOS 3, CEREC Omnicam, and Medit i500) under two rescanning strategies (full-cut and partial-cut), with varying numbers of repeated cut-off and rescanning procedures (0, 1, 3, 5, 7, or 10). The trueness discrepancy between the reference and experimental digital scan was estimated using root mean square (RMS) calculations. Three regions of interest were selected to represent the rescanning, identification, and non-rescan area. And the discrepancies were analyzed using a linear mixed model (α=0.05)., Results: Cut-off and rescanning procedures significantly decreased the trueness of digital scans in all test conditions compared to the reference. However, no progressive increase in discrepancy was observed under any rescan conditions. Significant influences on trueness were found based on the IOS used, with the 3Shape system exhibiting lower RMS values. The partial-cut strategy showed lower RMS values compared to the full-cut strategy, albeit without statistical significance., Conclusions: While repeated cut-off and rescanning procedures led to a decline in the quality of digital impressions, they did not result in discrepancy accumulation with repeated rescanning., Clinical Significance: To ensure high scanning accuracy in dental practice, it is advisable to minimize the rescanning area when correcting imperfections in digital scans. Additionally, selecting an appropriate scanner can help mitigate the negative effects of the rescanning technique., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Objectives: To measure the influence of scanning pattern on the accuracy, time, and number of photograms of complete-arch intraoral implant scans., Methods: A maxillary edentulous patient with 7 implants was selected. The reference implant cast was obtained using conventional methods (7Series Scanner). Four groups were created based on the scanning pattern used to acquire the complete-arch implant scans by using an intraoral scanner (IOS) (Trios4): manufacturer's recommended (Occlusal-Buccal-Lingual (OBL)), zig-zag (Zig-zag), circumferential (Circumf), and novel pattern that included locking an initial occlusal scan (O-Lock group) (n = 15). Scanning time and number of photograms were recorded. The linear and angular measurements were used to assess scanning accuracy. One-way ANOVA and Tukey tests were used to analyze trueness, scanning time, and number of photograms. The Levene test was selected to assess precision (α=0.05)., Results: Statistically significant differences in trueness were detected among OBL, Zig-zag, Circumf, and O-Lock regarding linear discrepancy (P<0.01), angular discrepancy (P<0.01), scanning time (P<0.01), and number of photograms (P<0.01). The O-Lock (63 ± 20 µm) showed the best linear trueness with statistically significant differences (P < 0.01) with Circumferential (86 ± 16 µm) and OBL (87 ± 19 µm) groups. The O-Lock (93.5 ± 13.4 s, 1080 ± 104 photograms) and Circumf groups (102.9 ± 15.1 s, 1112 ± 179 photograms) obtained lower scanning times (P < 0.01) and number of photograms (P < 0.01) than OBL (130.3 ± 19.4 s, 1293 ± 161 photograms) and Zig-zag (125.7 ± 22.1 s, 1316 ± 160 photograms) groups., Conclusions: The scanning patterns tested influenced scanning accuracy, time, and number of photograms of the complete-arch scans obtained by using the IOS tested. The zig-zag and O-Lock scanning patterns are recommended to obtain complete-arch implant scans when using the selected IOS., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objectives: This in vitro study was formulated to clarify how mandibular partial edentulous distal extension involving three missing teeth affects the virtual occlusal record (VOR) accuracy, in terms of both trueness and precision, when using two different intraoral scanners (IOSs) - the Primescan (PS) and Trios 4 (TR) scanners., Methods: A typodont model missing the left mandibular second premolar, first molar, and second molar as well as the right mandibular first molar was mounted on a semi-adjustable articulator. Four implants were placed at the sites of the missing mandibular teeth. Six pairs of stainless steel markers (diameter: 0.5 mm) were affixed to the maxillary and mandibular casts in the buccal gingiva adjacent to the implants and on the facial surfaces of teeth as reference positions for measurements. The model was digitized with an inEox X5 laboratory scanner to create a reference dataset. Intraoral scans were performed with the PS and TR scanners, with each scan duplicated 10 times to generate 20 paired IOS files. Automatic VOR generation followed the bilateral buccal scan protocol, divided into PS and TR groups (n = 10). Six subgroups of linear distances between interarch markers were assessed with Geomagic Control software, comparing deviations from the reference scan. Data normality was confirmed with the Shapiro-Wilk test. Trueness was evaluated with two-way ANOVAs and pairwise comparisons performed with Tukey's test, whereas precision was assessed with the Levene test (α=0.05)., Results: The mean linear deviation (Δd) and standard deviation (SD) of VOR were both significantly affected by marker position (P < 0.001), and a significant position × scanner interaction was detected (P < 0.001). Negative mean deviations were observed for the distally extended edentulous areas in both groups. PS scans exhibited trueness that was significantly better than that for TR scans in the D16-46, D13-43, D23-33, and D27-37 subgroups (P < 0.05), whereas there were no significant differences in the D25-35 or D26-36 subgroups. PS scanning was associated with significantly better precision than TR scanning (P < 0.001), and worse precision was observed at D27-37 for both tested IOSs., Conclusions: Mandibular partial edentulous distal extension can significantly affect VOR accuracy. The type of IOS could also affect VOR accuracy depending on the area being scanned, with better overall performance observed for the Primescan device as compared to the Trios 4 scanner. Both of these IOSs tended to underestimate VOR occlusal dimensions in mandibular distally extended edentulous areas., Clinical Significance: Mandibular distal edentulous areas can contribute to occlusal dimensions that are underestimated in digital workflows, which may result in infraocclusal discrepancies that arise when performing restorations. IOSs and VOR scanning protocols should thus be carefully considered in order to minimize these risks., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Objective: To analyse the maxillary arch dimensions of children aged 9 and 12 with unilateral cleft lip and palate (UCLP) who received orthodontic treatment and secondary alveolar bone grafting., Design: This retrospective cohort study was performed on 30 patients with UCLP., Setting: All patients were treated at the Cleft Lip and Palate Centre, which is part of the University Medical Centre Amsterdam and Academic Centre for Dentistry Amsterdam, the Netherlands., Patients/participants: Children with non-syndromic UCLP who received pre- and postsurgical orthodontics combined with secondary alveolar bone grafting between the ages of 9 and 12 years were included., Main Outcome Measures: Maxillary arch dimensions were assessed on 60 digitised dental casts with measurements of the intermolar widths, interpremolar widths, arch perimeters, arch lengths, arch widths, and palatal depths., Results: The results of a paired-samples t -test revealed a statistically significant increase ( P  < .05) in intermolar width 1, intermolar width 3, interpremolar width 1, arch perimeter, and arch width between the ages of 9 (T0) and 12 (T1). Intermolar width 2 and the palatal depth decreased statistically significantly between T0 and T1., Conclusions: Analysis of maxillary arch dimensions of children with UCLP indicates significant changes between 9 and 12 years of age. This suggests that orthodontic treatment and secondary alveolar bone grafting can be effective in improving maxillary arch dimensions. However, there is a need for collaborative research and data collection in order to provide sensible and evidence-based care to patients with cleft lip and palate., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: To date, no suitable model tooth has been available for all standard restorative and prosthodontic procedures. To fill this gap, a realistic multilayer tooth with enamel, dentin, integrated caries, pulp, and electrometric and X-ray imaging abilities was developed. The aim of this study was to test the printed tooth while focusing on caries excavation and pulp capping., Methods: Based on micro-CT data, a tooth was designed and produced via 3D printing. A total of 396 teeth were tested and evaluated by 66 fourth- and fifth-year students experienced in caries excavation at standard typodonts, extracted teeth and patients. They excavated the caries and capped the pulp on six teeth and rated them in a questionnaire., Results: Compared with natural teeth, the printed teeth were generally rated positively and significantly better in all criteria than typodonts used previously (p < .001). They were rated as a suitable training option (Ø 2.3 ± 0.9) with fair examination conditions (Ø 2.1 ± 0.8) and easy to use (Ø 2.0 ± 0.8). Subjective learning success was also significantly greater (Ø 2.3 ± 0.9) than that of standard typodonts (Ø 3.2 ± 1.1) (p < .001). In general, the students desired more exercises with 3D-printed teeth for their studies (Ø 1.8 ± 0.8)., Conclusions: Multilayered 3D-printed teeth were successfully tested and can improve and extend the teaching methods used for caries excavation and pulp capping. Its other abilities will be tested in subsequent studies., Year of the Study: 2023., (© 2024. The Author(s).)

Background: Placing implants deep sub-gingivally may affect the accuracy of implant impression techniques and the fit of final restoration., Purpose: The aim of this in-vitro study was to evaluate the effect of soft tissue thickness on accuracy of conventional and digital implant impression techniques., Methods: Four parallel implant analogues (A, B, C, D) placed in each of two epoxy resin models representing edentulous mandible covered by flexible polyurethane material with two different thickness two mm and four mm. A total of sixty impressions performed, thirty impressions for each model divided into four groups (n = 15 per group) GI (C2mm) open tray impression with two mm implant depth, GII (C4mm) open tray impression with four mm implant depth, GIII (D2mm) digital impression with two mm implant depth, GIV (D 4 mm) digital impression with four mm implant depth. Impressions from open tray technique were poured to get stone casts while impressions from digital scanning technique were printed as three-dimensional printed casts. The six inter-implant distances between analogues were measured using Co-ordinate measuring machine, deviations compared to reference models were calculated. Data was collected, tabulated and statistically analyzed using One-way ANOVA test to detect significances between groups., Results: For conventional impressions there was significant difference between C2mm/C4mm (P < 0.001) regarding interimplant distance, while in digital impressions there was no significant difference between D2mm/D4mm AB(p = 0.110), BC(p = 0.066), CD(p = 0.710), AD(p = 0.084), AC(p = 0.067) and BD(p = 0.072). There was significant difference between conventional and digital impression techniques C2mm/D2mm, C4mm/D4mm (P < 0.001)., Conclusion: Within the limitations of this in-vitro study digital impressions provide more accurate outcomes with implants placed deeper subgingivally than conventional impressions., Trial Registration: Retrospectively registered., (© 2024. The Author(s).)

Objectives: The limited number of studies using digital workflows to measure soft tissue changes depend on the cemento-enamel junction (CEJ), which has been reported to be unreliable. Our primary objective was to apply an advanced digital assessment method, measuring independent from the CEJ to evaluate the modified coronally advanced tunnel technique (MCAT) with a porcine dermal matrix (PDM) for gingival recession coverage., Materials and Methods: Patients with type RT1 and RT2 gingival recessions were treated with the MCAT and a PDM. Plaster casts (preoperative and 6 months postoperative) were digitalized. Subsequent stereolithography (STL)-files were imported and superimposed in the open-source software GOM Inspect for computer-based analysis. Recession depth, mean root and complete root coverage (mRC and cRC), mean recession reduction (mRR) and gingival thickness were evaluated. Statistical analysis was performed using mixed linear models., Results: A total of 82 teeth (19 patients) were included in the study. Healing was uneventful in all patients. The mean preoperative recession depth was 1.34 ± 0.92 mm. mRC was 65.06 ± 48.26%, cRC was 25.61%, mRR was 0.87 ± 0.83 mm, and gingival thickness gain was 0.33 ± 0.30 mm, with comparable results for RT1 and RT2. Neither tooth type nor type of jaw had any effect on the amount of root coverage., Conclusions: The digital evaluation workflow employed offers an approach to evaluate gingival recession coverage outcomes independent of the CEJ. The PDM used in combination with the MCAT shows promising results for root coverage., (© 2024. The Author(s).)

The objective of this study was to compare the aging changes of the dental arches in patients treated without extractions and untreated normal occlusion subjects after a four-decade follow-up. This retrospective study evaluated two groups: The Treated Group (Group T) comprised 16 patients (6 male; 10 female) presenting with Class I or Class II malocclusions treated orthodontically without extractions. Dental models were evaluated 3 stages: T1 (pretreatment, 13.20 years), T2 (posttreatment, 15.07 years) and T3 (long-term posttreatment, 50.32 years). The Untreated Group (Group UT) consisted of 22 untreated normal occlusion individuals. The dental casts were evaluated at the ages of 13.32 (T1), 17.82 (T2) and 60.95 years (T3). The dental casts were digitized and the irregularity index, intercanine, interpremolar and intermolar widths, overjet and overbite, arch length and perimeter were measured. Intergroup comparisons were performed with independent t tests (P < 0.05). From T1 to T2, the treated group showed maxillary and mandibular crowding and overjet decrease and a maxillary interpremolar and intermolar width increase compared to the untreated group. From T2 to T3, a greater maxillary and mandibular crowding increase and a greater arch length decrease were observed in the treated group compared to the normal occlusion subjects. Overbite increased in the treated group and decreased in the untreated group. The maturational changes of treated patients were different from untreated normal occlusion subjects. Relapse might have contributed for the greater changes observed in incisor crowding and arch length observed in orthodontically treated patients. The aging changes of untreated normal occlusions and nonextraction treated patients, after a four-decade follow-up, proved to be different, indicating that relapse of orthodontic treatment played a role in aging changes of treated patients., (© 2024. The Author(s).)

Objectives: Investigate the effect of different postpolymerization protocols, aging, and 3D printing systems on the flexural strength (σ), dimensional stability, and roughness of resins used to fabricate occlusal splints, dental models, and temporary restorations., Material and Methods: 180 bars (25 × 2 x 2 mm-ISO 4049) of each type of resin (T-Temporary/Cosmos Temp, Yller; OS-Occlusal splint/Cosmos Splint, Yller; MO - Models/ Cosmos Model, Yller) were printed and divided into 12 groups (n = 15) according to the factors: "Postpolymerization" (Ctr - Control; UV - Ultraviolet oven and MW - Microwave); "Printer" (SLA- stereolithography (Forms 2/Formslab); LCD- liquid crystal display (FlashForge Foto 6.0/FlashForge)) and "Aging" (TC - 10,000 thermocycling cycles and Without). Each bar was measured with a digital caliper at 11 points before and after postpolymerization to evaluate dimensional stability. The samples were subjected to the σ test (100Kgf;1 mm/min). Data was evaluated using Three- and Two-way ANOVA, and Tukey's test (5%). Weibull analysis, Scanning Electron Microscopic and optical profilometry was performed., Results: LCD printing system and UV oven postpolymerization exhibited the highest σ (P < .05). The groups printed in SLA and post-polymerized in microwave ovens showed the greatest variations in their dimensions, for the occlusal splint resin, the OS-SLA-MW group (-4.29 ± 3.15) A showed a shrinkage of 40.2%. The resins for models (3.31 ± 0.66) A and temporary (-2.06 ± 1.52) A showed a shrinkage of 33% and 20.6%, respectively., Conclusions: LCD printing with UV light postpolymerization was the most effective method for resins used in occlusal splints, dental models, and temporary restorations. SLA printing with UV postpolymerization showed the most significant dimensional changes, leading to shrinkage in occlusal splint resins, while model resins and temporary restorations expanded., Clinical Relevance: Resins for 3D printing should ideally be post-polymerized with UV light and printed using LCD technology, as this approach results in better mechanical properties and less dimensional change compared to microwave oven post-polymerization., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The following technique describes the virtual planning of a single implant by combining an intraoral digital scan, an open-source computer-aided design software program, bone sounding, and 2D radiographic imaging. The surgical implant guide is fabricated using additive manufacturing technologies. Further, the surgical implant guide positioned in the patient's mouth is used to radiographically verify the estimated mesiodistal implant angulation before proceeding with the surgical intervention and can be modified if necessary. When a CBCT scan is not available, this technique eases implant planning procedures and minimizes possible surgical complications.

Aim: The aim of the present study was to evaluate the segmentation accuracy of the dentition by testing four open-source semi-automatic software programs., Materials and Methods: Twenty CBCT scans were selected to perform semi-automatic segmentation of the maxillary and mandibular dentition. The software programs tested were InVesalius, ITK-SNAP, 3D Slicer, and Seg3D. In addition, each tooth model was manually segmented using Mimics software; this was set as the gold standard (GS) reference of the investigation. A specific 3D imaging technology was used to perform the superimposition between the tooth models obtained with the semi-automatic software and the GS model as well as to perform the surface-to-surface matching analysis. The accuracy of semi-automatic segmentation was evaluated, calculating the volumetric mean differences (mean bias and limits of agreement) and the percentage of matching of the tooth models compared with the manual segmentation (GS). Qualitative assessments were performed using color-coded maps. All data were statistically analyzed to perform comparisons between the investigated software programs., Results: Statistically significant differences were found in the volumetric and matching percentage data (P 0.05). InVesalius was the most accurate software program for 3D rendering of the dentition, with a volumetric bias (Mimics software) ranging from 4.59 to 85.79 mm3, while ITK-SNAP showed the highest volumetric bias, ranging from 30.22 to 319.83 mm3. The mismatched area was mainly located at the radicular tooth region. The volumetric data showed excellent inter-software reliability, with coefficient values ranging from 0.951 to 0.997., Conclusion: Different semi-automatic software algorithms could generate different patterns of inaccuracy error in the segmentation of teeth.

The goal of this study was to digitally evaluate the development of maxillary dental arches of children with unilateral cleft lip and palate treated with one- and two-stage palatal closure. One hundred and sixty-eight digitized dental models of cheiloplasty and one-stage palatoplasty (G1) and cheiloplasty and two-stage palatoplasty (G2) were evaluated at preoperative time 1 (T1), preoperative time 2 (T2), and postoperative (T3). The following surface distances were evaluated: across surface distance; cleft widths anterior (P-P') and posterior (U-U') cleft widths, intercanine width (C-C'), and intertuberosity width (T-T'); smallest (P'-T') and largest (P-T) segment lengths; and smallest (C'-D') and largest (C-D) segment cleft depths. In G1, P-P', U-U', and C-C' reduced at T2, unlike P'-T' (P<0.05). P-T and C'-D' distances increased at T3 (P<0.05), while C-D increased at all stages (P<0.001). In G2, U-U' and C-C' reduced at T2 (P<0.05), while P'-T', P-T, C'-D', and C-D' increased at T3 (P<0.001). In an intergroup analysis of growth rate, G2 showed higher growth percentages compared to G1, in which C'-D' was significant (P=0.038). Furthermore, C'-D' presented a coefficient of determination of 0.076 (P=0.039). In conclusion, dental arch development is influenced by the rehabilitation protocol. However, in the sample evaluated, the comparison suggested that individuals whose palate was operated on in two stages had the most favorable palatal growth.

Introduction: The use of arch models is essential in diagnosis and planning in orthodontics. The demand for digital and printed models has increased among professionals., Objective: The aim of the study was to assess the agreement of horizontal and vertical linear measurements obtained from digital models, printed models, and direct measurements., Materials and Methods: Intraoral scans of 30 individuals were obtained. Digital measurements were performed using the STL files. From printed models, the measurements were done using a digital caliper, and the real measurements were done directly to the mouth of respective patients., Results: The one-sample t test showed no discrepancy between the paired sets of measurements, with the value of 0 (p>0.05). The evaluation of the measurements was done using Bland-Altman analysis in pairs. The three methods showed agreement in horizontal and vertical measurements. Linear regression analyses showed no proportional bias in the data (p>0.05)., Conclusion: The horizontal and vertical measurements evaluated showed agreement when measured on digital models, printed models and directly in the individuals' mouths.

Purpose: To evaluate the scanning strategies affecting the accuracy of virtual interocclusal records (VIR) in partially edentulous arches using an intraoral scanner in vitro., Methods: A reference model of a partially edentulous arch with implant analogs in positions 45,46 and 47 was constructed. Six pairs of 1-mm diameter metal beads were placed on the gingival tissue as markers for measurement. Four scanning strategies were tested: Quadrant-arch Scan (group 1), Quadrant-arch Scan with Auxiliary occlusal devices (AOD) (group 2), Full-arch Scan (group 3), Full-arch Scan with AOD (group 4). The model was digitalized with a lab scanner as a reference and 15 scans were obtained for each group. The accuracy of VIR was assessed by comparing the experiment data to the reference digital model., Results: The mean surface deviations of VIR for Groups 1-4 were 89.4 ± 105.2 μm,95.6 ± 132.8 μm,152.3 ± 159.7 μm and 107.6 ± 138.2 μm respectively. Quadrant-arch scans resulted in lower errors of VIR than full-arch scan (P < 0.001). There was a significant interaction between the AOD and scanning span (P = 0.017). The Quadrant-arch scan with AOD　(group 2) produced the least error in the distally extended edentulous area., Conclusions: Quadrant-arch scans showed better accuracy of VIR than full-arch scans across all tooth positions. The combination of AOD and quadrant-arch scan further enhances VIR accuracy in distally extended edentulous areas., (© 2024. The Author(s).)

Background: In edentulous jaws, factors such as the number of implants, cross-arch distribution, and the angle among implants may affect the accuracy of the implant impression. This study explored factors influencing the accuracy of implant abutment-level digital impressions using stereophotogrammetry in edentulous jaws., Methods: Two standard all-on-4 and all-on-6 models of edentulous jaws were constructed in vitro. In the stereophotogrammetry group (PG), the implant digital impression was made using stereophotogrammetry and saved as an STL file. In the conventional group (CNV), the impression was made using the open-tray splint impression technique. An electronic and optical 3D measuring instrument was used to scan the standard model and the conventional plaster model to obtain STL files. Using 3D data processing software (GOM Inspect Pro, Zeiss), the distance and angle between the abutments in the CNV impression and the PG impression were measured and compared with the data from the standard model., Results: The distance deviation in the PG and the CNV was 145 ± 196 μm and 96 ± 150 μm, respectively, with a significant difference (P < 0.001). The angle deviation in the PG and the CNV was 0.82 ± 0.88° and 0.74 ± 0.62°, respectively, with no significant difference (P = 0.267). In the PG, the distance deviation was negatively correlated with the distance between implants (r = -0.145, P = 0.028) and positively correlated with the angle of implants (r = 0.205, P = 0.002). The angle deviation was negatively correlated with the distance between implants (r = -0.198, P = 0.003) and positively correlated with the angle of implants (r = 0.172, P = 0.009). In the CNV, the effect of inter-implant distance on impression accuracy was also shown by Spearman correlation analysis: r = 0.347 (P < 0.001) for distance deviation and r = -0.012 (P = 0.859) for angle deviation. The effect of inter-implant angulation on impression accuracy deviation was r = -0.026 (P = 0.698) for distance deviation and r = 0.056 (P = 0.399) for angle deviation., Conclusions: The CNV method is closer to the real value of the original model. The distance between implants and the distribution angle had a weak correlation with the accuracy of digital impressions but no significant correlation with the accuracy of traditional impressions., (© 2024. The Author(s).)

Purpose: To evaluate the marginal and internal misfit of fixed partial denture zirconia frameworks developed from conventional impression and intraoral scanning, before and after being subjected to the thermal cycle of the covering ceramic., Methods: A three-elements fixed partial denture was prepared, molded, and poured with polyurethane. Group CI (n= 7) was impressed by the conventional technique with polyvinyl siloxane material, and the plaster models scanned on the inEosX5 bench scanner. Group DI (n=07) was scanned using the CEREC Bluecam intraoral scanner. The models and images obtained were sent to the laboratory and the frameworks were made using zirconia blocks. After this, they were subjected to the ceramic thermal cycle, simulating the ceramic application. Marginal and internal misfits of the frameworks were measured before (T1) and after (T2) thermal cycle simulation using the replica technique in an optical microscope. Statistical analysis was performed using the mixed effects of linear model tests and comparisons., Results: There were no statistical differences for axial misfit. Significant differences were found between the groups for occlusal, vertical, horizontal, and absolute misfit, where group CI had higher values than group DI (P< 0.001). At the time, there was a statistical difference only in the absolute misfit, where T1 had lower values than T2. The misfit in group CI was greater than in group DI; however, the average misfit values found are low and considered clinically acceptable., Clinical Significance: Knowing marginal and internal misfit is an important step to consolidating digital impressions in fixed partial dentures, implying a secure use of this technique., Competing Interests: The authors declared no conflict of interest. The project was funded by FORP/USP and the National Council for Scientific and Technological Development (Grant number: 1678421, 2017)., (Copyright©American Journal of Dentistry.)

Background: Forensic odontology involves the identification of individuals through dental records, making it a crucial tool in legal investigations. Non-metric dental traits (NMDT), which are variations in dental morphology play a key role as these traits are inherited characteristics that can help establish biological relationships or ancestry. Thus, we aim to assess the frequency and variability of NMDT in the human dentition of four ethnically mixed populations in Uttar Pradesh. This study can aid in the future by maintaining records of ethnic groups and their variability, which can be crucial for disaster victim management and forensic odontology., Methods: The study was conducted on a total of 100 patients coming to the OPD of Oral Medicine and Oral Pathology and Microbiology of King George's Medical University from January 2022 to July 2023. Impressions of both arches were made for participants using irreversible hydrocolloid (alginate), and casts were examined under a stereomicroscope to assess 15 different morphological characteristics., Results: NMDTs such as winging, shoveling, double-shoveling interruption groove, canine mesial ridge, hypocone, metacone, carabelli's trait, peg-shaped incisors, peg-shaped molar, premolar lingual cusp variation, deflecting wrinkle, protostylid, metaconulid, entoconulid was evaluated. The NMDTS were evaluated in four different ethnics Nordics, Mediterranean, Oriental Mediterranean, and Protoaustraloid amongst which various traits showed a statistically significant variation among the population of Uttar Pradesh., Conclusion: The sample studied presented confirmed supernumerary traits like metacone, protostylid, carabellis trait, metaconulid, premolar lingual cusp variation, and deflecting wrinkle were seen highest in Nordic, Mediterranean, Oriental Mediterranean, and Protoaustraloid ethnicity have a significant association with the Uttar Pradesh population., Competing Interests: Declaration of competing interest No conflict of interest among the authors., (Copyright © 2024 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.)

Background: This study aims to verify Bolton's values for tooth size ratios and to evaluate possible relationships to different occlusal traits using precise digital measurement methods., Materials and Methods: Including 1000 consecutively selected patients from three study centres a digital, partially automated model analysis was performed utilizing the software OnyxCeph. The measurements comprised tooth width for calculation of anterior (AR) and overall ratio (OR) as a percentage, arch width, length, perimeter, overjet, overbite, space analysis in millimetre and the assessment of the angle classification., Results: AR and OR were significantly increased compared to Bolton's ratios of 77.2% (AR) and 91.3% (OR). In the gender comparison, male patients showed larger tooth size ratios, especially in the OR. Patients with Angle Class II/1 and II/2 had smaller tooth size ratios than patients with Angle Class III and I. Thus, patients with Angle Class II/1 had the largest tooth diameters in all maxillary teeth and with Angle Class II/2 the smallest tooth sizes in the mandible. The largest tooth widths in the lower jaw were observed in the Angle Class III patient group. Furthermore, a negative correlation from AR/OR to overjet, overbite, and available space in lower jaw as well as a positive correlation to available space in upper jaw was detected., Conclusions: There is a clear correlation between the tooth size ratios and the present dysgnathia as well as other orthodontically relevant occlusal traits. This prior knowledge about our patients is extremely important to create an individualized treatment plan and enable sufficient occlusion. To achieve a functionally good occlusion with correct overjet and overbite, it is essential that the maxillary and mandibular teeth are proportional in size. Any deviation from the ideal patient in terms of tooth size, number, shape, or arch must be considered in the pre-therapeutic treatment plan in combination with the existing dysgnathia in order to be able to achieve a stable anterior and posterior occlusion with appropriate adjustments to the therapy post-therapeutically., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: As artificial intelligence within digital processes continues to advance and replace conventional manual workflows, it is crucial that digital data are consistent with analog data. The aim was to evaluate the validity and time efficiency of digital cast analysis on digital models in comparison with the manual, gold standard, cast analysis on plaster models., Methods: Cast analysis was performed on 30 patients in three various methods: manually measured variables on plaster models (MP), manually measured variables on digital three-dimensional models (MD), and automatically measured variables on digital three-dimensional models (AD) on digital models. Digital cast analysis was performed in CS Model+. Analyses included metrical and categorical variables and the required work time. Measurements in MD and AD were validated to MP. Validity of the metrical variables was analyzed with Bland-Altman, Dahlberg's formula, and paired sample t test. Categorical variables were validated by Cohen's Kappa. Work time was analyzed with Wilcoxon signed-rank test., Results: Metrical variables had measurement errors ranging 0.4 to 1.4 mm between MP-MD, and 0.6 to 3.2 mm between MP-AD. Observations of categorical variables had a moderate to strong (0.65 to 0.9) level of agreement between MP-MD, and a weak to moderate (0.4 to 0.68) level of agreement between MP-AD. Data for dental stage, vertical, and transversal relation was not provided in AD. Cast analysis was performed quicker digitally, P ≤ 0.05., Conclusions: Digital cast analysis is consistent with manual cast analysis for metrical variables. Analyses of categorical variables show a weak level of agreement with automatic digital analysis, such as space conditions and midline assessments. Digital cast analysis optimizes time compared with manual cast analysis, with automatic analysis being the fastest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: The purpose of the study was to investigate the influence of different preparation designs and scan patterns on the accuracy of intraoral scans for complete-arch maxillary laminate veneers., Materials and Methods: Three maxillary typodonts were used to obtain reference models with three different laminate veneer preparation designs: windows (W), beveled (B), and incisal overlap (IO). Reference scans were obtained with a desktop scanner. A total of 90 complete arch intraoral scans were made with an intraoral scanner (Medit i700) following three different scan patterns: straight motion (SM), zigzag motion (ZM), and combined motion (CM). Ten scans were made in each subgroup and exported as standard tessellation language (STL) files. Assessment of accuracy was conducted with a 3D software analysis program (Geomagic Control X). Each STL file was individually aligned with the reference scan using the best fit algorithm tool, and 3D differences were calculated using the root mean square (RMS) value. Two-way analysis of variance (ANOVA) followed by post hoc comparison tests were applied to analyze precision and trueness data (α = 0.05)., Results: Two-way ANOVA and post hoc comparison tests revealed significant differences among different preparation designs and scan patterns (p < 0.05). Regarding trueness, the IO when scanned with SM presented higher mean RMS than the other preparation designs (W and B) scanned with the same scanning pattern (p < 0.05). Regarding precision, the groups of W and IO presented significantly higher mean RMS than the group of B when scanned with ZM (p < 0.05)., Conclusions: Accuracy of intraoral scans for complete-arch laminate veneers was affected by different laminate veneer preparation designs and scan patterns., Clinical Significance: Modifying scan pattern according to preparation design helps to improve scan accuracy for complete-arch laminate veneers., (© 2024 The Author(s). Journal of Esthetic and Restorative Dentistry published by Wiley Periodicals LLC.)

Purpose: Although a series of studies on OXIS contacts have been performed, studies regarding changes in OXIS contacts over time are lacking. Therefore, this study aimed to evaluate the change in contact type between primary molars after 3 years in children aged 3-7 years., Methods: This longitudinal study was conducted using 2922 sectional die models of 926 children. At baseline (T0), the contact type between the primary molars was scored using replication via the sectional die model method according to the OXIS criteria. After 3 years, the sectional die models of the same children were scored using the same criteria (T1)., Results: McNemar's tests revealed a significant change in contacts from baseline to 3 years. The post hoc test explained specific changes in the contacts that were observed to be significant. These were O to X (p < 0.001), O to I (p < 0.001), O to S (p = 0.035), and I to X (p < 0.001)., Conclusions: A significant change in OXIS contact over time was observed. The O-type contact underwent the maximum change. The least and most stable contacts are the "O" and "I" types, respectively. This change in contact type with age may alter the risk of caries in children., (© 2024. The Author(s), under exclusive licence to European Academy of Paediatric Dentistry.)

Objectives: This study aimed to evaluate the accuracy of computer-aided design and computer-aided manufacturing (CAD-CAM)-assisted templates (CCAT), guiding rod templates (GRT), and freehand (FH) preparation of guide planes., Methods: Forty-five identical maxillary resin casts were divided into three groups, in which the guide planes of the two abutment teeth were prepared using a CCAT (n=15), GRT (n=15), and FH (n=15). The CCAT and GRT were digitally designed on a digital cast of virtually prepared guide planes and fabricated using three-dimensional printing (3DP) technology. To assess the 3D trueness, the prepared guide planes were digitally scanned and compared to the virtually designed guide planes. The angle deviation was measured to assess the trueness of the direction of the guide plane preparation. Shapiro-Wilk and Levene's tests were used to check the normality and equivalence of the variance of the data. The data were compared by using the Kruskal‒Wallis H test (α=0.05)., Results: The CCAT group exhibited significantly better 3D trueness (78.5±19.8 μm) than the GRT group (211.3±42.4 μm, p<0.05) and the FH group (198.9±44.3 μm, p<0.05). Additionally, the CCAT group (1.31±0.50°) showed significantly smaller direction trueness compared to the GRT (4.65±0.72°, p<0.05) and FH (5.64±0.70°, p<0.05) groups., Conclusions: The novel CAD-CAM-assisted template significantly improved the quality of the guide planes compared with the GRT and FH procedures. This enhancement suggests that removable partial dentures can be predictably inserted immediately after guide plane preparation., Clinical Significance: CAD-CAM-assisted templates improve the quality of guide plane preparation., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Statement of Problem: Static guided implant surgery may be the most accurate method of implant placement to date. However, within the same guided implant system, whether accuracy is affected when placing a larger diameter implant that requires more drills than a smaller diameter implant is unclear., Purpose: The purpose of this in vitro study was to evaluate the influence of implant diameter on the angulation and 3-dimensional (3D) deviations of posterior single implant placement using static guided surgery., Material and Methods: A polyurethane dental cast was made with an edentulous site at the maxillary right first molar position. Identical implant planning for each of 3 dental implant diameters 3.3, 4.1, and 4.8 mm (Straumann BLT) were made, and surgical guides for each implant diameters were fabricated by stereolithography. Fifteen implants of each diameter (N=45) were placed in simulated casts. A scan body was placed and the cast was scanned using an intraoral scanner. The positional discrepancies of implant placement, including angulation as well as 3D implant cervical and apex area deviations, were compared with the planned position. Linear ANOVA single factor analysis (ɑ=.05) was used, and box plots were made., Results: The ranges of angulation deviations for 3.3-, 4.1-, and 4.8-mm implants were 3.6 degrees to 6.0 degrees, 3.7 degrees to 7.7 degrees, and 3.1 degrees to 6.7 degrees, respectively. The ranges of 3D implant entry deviations of 3.3-, 4.1-, and 4.8-mm implants were 0.96 to 1.4, 0.85 to 1.72, and 0.89 to 1.78 mm, respectively. The ranges of 3D implant apex of 3.3-, 4.1-, and 4.8-mm implants were 0.63 to 1.21, 0.64 to 1.48, and 0.48 to 1.27 mm, respectively. No statistically significant differences were found in any of the 3 measurements: P=.67 for deviation in angulation; P=.27 for 3D implant deviation of entry; and P=.3 for 3D implant deviation of the apex., Conclusions: Implant diameters had no significant effect on placement deviations when a single posterior static guided surgery was used., (Copyright © 2022 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Objective: To assess the diagnostic validity of ICDAS clinical criteria on 3D dental models from intraoral scanning., Methods: This is a retrospective analysis on part of the baseline sample collected in a cohort study and included 73 participants (12-19 years) from Denmark and Greece. The assessment was made by visual inspection, and then by visual inspection associated with radiographs. All participants were scanned with TRIOS 4 which uses white light to obtain the 3D models with tooth color, as well as blue light source (415 nm) for fluorescence. The 3D models' evaluation was conducted using tooth-color texture and subsequently fluorescence. Two scores were obtained for the 3D model examination: i) ICDAS based on tooth-color information; ii) ICDAS based on tooth-color information supplemented with fluorescence. For the analysis, weighted kappa, sensitivity (SE), specificity (SP) and accuracy (ACC) were calculated., Results: Regarding all lesions the values for SE, SP, and ACC were respectively 0.804, 0.801, and 0.802 for tooth-color, and 0.819, 0.808, and 0.810 for tooth-color supplemented with fluorescence. In terms of accuracy parameters for moderate-extensive lesions, the values for SE, SP, and ACC for tooth color were 0.709, 0.948, and 0.944, while for fluorescence they were 0.815, 0.937, and 0.934., Conclusion: Caries assessment with ICDAS criteria on 3D dental models produces reliable scores. Visual caries analysis using 3D models demonstrates commendable diagnostic accuracy and reasonable consistency with traditional methods. The use of intraoral scanners may be beneficial in evaluating occlusal caries., Clinical Significance: The importance of this study is to prove the diagnostic accuracy of caries lesions diagnosis made using and intraoral scanner and to offer greater confidence to professionals who use this diagnosis tool in their daily clinical practice. Intraoral scanners demonstrate to be an accurate tool for diagnosing occlusal caries., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: When this study was conducted, the co-author Stavroula Michou was employed at 3Shape TRIOS A/S. The other authors declare no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Purpose: To evaluate the overall adaptation and retention of class I cobalt-chromium (Co-Cr) removable partial denture (RPD) frameworks using three different computer-aided design and computer-aided manufacturing (CAD-CAM) technologies: Indirect wax milling with lost wax technique (LWT), direct milling, and selective laser melting (SLM) technique., Materials and Methods: An educational maxillary stone model (Kennedy class I) was scanned after preparing rest seats to create a resin model. The resin model was scanned, and the RPD framework was digitally designed and saved as a standard tessellation language (STL) file. Twenty-four Co-Cr RPD frameworks were then constructed and divided into three groups (n = 8) based on fabrication technique: Group A (indirect wax milling with LWT), Group B (direct milling), and Group C (selective laser melting). In Group A, the STL file was used to mill the design from castable resin blanks which were then cast by the LWT. In Group B, the STL file was used to mill the design from the Co-Cr blank directly. Finally in Group C, the STL file was used to print the design from Co-Cr powder using SLM 3D printed technique. Geomagic Control X software was used to measure the overall adaptation of the fabricated RPD frameworks, Retention was also tested using a universal testing machine. One-way Analysis of Variance (ANOVA) test was used to compare the three groups then the Tukey HSD post-hoc test was used for pair-wise comparisons. The significance level was set at p ≤ 0.05., Results: Regarding the overall adaptation, Group B (0.71 ± 0.02 mm) showed significantly higher adaptation than Group A (0.96 ± 0.06 mm) and Group C (1.05 ± 0.16 mm). Regarding retention, Group B (2.03 ± 0.34 N) showed significantly higher retention than Group A (1.00 ± 0.13 N) and Group C (0.78 ±0.17 N)., Conclusion: Based on the findings of this in vitro study, Co-Cr RPD frameworks fabricated by direct milling technique revealed the best adaptation and retention., (© 2023 by the American College of Prosthodontists.)

Objectives: We conducted a three-dimensional (3D) analysis of orthodontic tooth movement (TM) using digital dental models (DMs), focusing on the palatal region of interest (PROI), aiming to evaluate the long-term stability of the PROI, validate the 3D TM analysis with PROI registration, and compare it with conventional lateral cephalometric analyses., Methods: Twenty adult patients treated with a multibracket appliance were evaluated at their first visit (T0) and at least 5 years later (T1) using DMs and lateral cephalograms (LCs). The long-term stability of PROI was assessed by calculating the point cloud distances between DM-T0 and DM-T1. TM analysis using DM with PROI registration for the maxillary central incisors was assessed through linear and angular measurements in the sagittal view and subsequently compared with the LCs., Results: The average point cloud distance of the PROI between DM-T0 and DM-T1 was 0.21 mm (standard deviation, 0.13 mm). TM analysis using DMs demonstrated excellent reproducibility for both linear and angular measurements (intra-rater correlation coefficient, > 0.99). The 95 % limits of agreement between the DM and LC measurements were < 5.14° for angular change, 3.53 mm for horizontal displacement, and 0.98 mm for vertical displacement. No significant differences were observed in the angular and linear measurements when the TM was compared using the DMs and LCs., Conclusions: The PROI remained stable for over 5 years, supporting the reproducibility and accuracy of TM assessment using PROI registration in orthodontic clinical practice., Clinical Significance: DM analysis lacks the risks associated with X-ray exposure and can be easily performed in daily clinical practice, indicating its potential for future clinical applications. These findings further support the use of DM with PROI registration for TM analysis in orthodontic clinical practice, emphasizing its long-term stability and reproducibility., Competing Interests: Declaration of competing interest I, Kenji Fushima, hereby declare that I have no conflicts of interest related to the submitted article titled ' Long-term Stability of the Palatal Region of Interest to Assess Tooth Movement'. I have no financial or personal relationships with individuals or organizations that could influence or be perceived to influence the research or findings presented in this article. This includes, but is not limited to, employment, consultancies, honoraria, stock ownership, or any other competing interests. I affirm that the content of this article is solely based on the objective pursuit of knowledge and scientific inquiry., (Copyright © 2024. Published by Elsevier Ltd.)

Introduction: Accurate bracket positioning remains challenging. To avoid angulation errors, some recommend examining the panoramic radiograph during bonding. However, it can cause distortions. Cone-beam computed tomography (CBCT) provides a more precise panoramic reconstruction but with higher radiation doses. The main objective of this study is to compare the accuracy of axial positioning between direct bonding without radiography, with conventional panoramic radiograph, and with panoramic reconstruction from CBCT. The secondary objectives are to evaluate positioning accuracy of each tooth and to assess the influence of practitioner level of experience., Methods: Thirty practitioners, divided into two groups based on their experience performed direct bonding on a model thrice: without radiography, then with the conventional panoramic radiograph, then with the panoramic reconstruction from CBCT. Models were scanned, and angulation errors were measured using OrthoAnalyzer. Values were compared using the Friedman's test followed by the Bonferroni correction for multiple comparisons (P-value = 0.05)., Results: For the low level of experience group, angulation errors were significantly greater than the accepted limit without radiographic reference, and significantly lower with CBCT reconstruction. For the high level of experience group, angulation errors were significantly lower than the accepted limit for the three bonding methods. For every tooth, using the panoramic reconstruction from CBCT as a reference, was the most accurate method, regardless of the level of experience. More experienced practitioners made fewer errors for the three methods., Conclusions: Panoramic reconstruction from CBCT is the most accurate method to limit angulation errors during direct bonding. Conventional panoramic radiography remains a reliable tool if used with caution. Bonding without any radiographic reference should be avoided especially for less experienced practitioners., (Copyright © 2024. Published by Elsevier Inc.)

Objectives: The present study aimed to systematically review the studies comparing the accuracy of intraoral scan (IOS) and conventional implant impressions (CI) in completely edentulous patients., Materials and Methods: Electronic searches were performed in PubMed, Embase and Cochrane CENTRAL up to December 1, 2023. Clinical studies and in vitro studies reporting the accuracy of digital full arch impressions were included. The primary outcome is the 3-dimensional deviations between the study reference models. A risk of bias assessment was performed for clinical studies. A stratified meta-analysis and a single-armed meta-analysis were conducted., Results: A total of 49 studies were included, with 8 clinical studies and 41 in vitro studies. For comparison between IOS and conventional impressions, studies were categorized into two groups based on the different measurement methods employed: RMS and CMM. In studies using RMS, the result favored the IOS in the unparalleled situation with the mean difference of -99.29 μm (95% CI: [-141.38, -57.19], I 2  = 81%), while the result was opposite with the mean difference of 13.62 μm (95% CI: [10.97, 16.28], I 2  = 26%) when implants were paralleled. For different brands of IOS, the accuracy ranged from 76.11 μm (95% CI: [42.36, 109.86]) to 158.63 μm (95% CI: [-14.68, 331.93])., Conclusions: Accuracy of intraoral scan is clinically acceptable in edentulous arches, especially for unparalleled implants. More clinical studies are needed to verify the present finding., (© 2024 Wiley Periodicals LLC.)

Statement of Problem: Scan path length and the presence of edentulous alveolar ridge sections have a negative influence on scanning accuracy. How different artificial landmarks combined with an adapted scanning method affect accuracy is unclear., Purpose: The purpose of this in vitro study was to determine the influence of 2 different artificial landmarks combined with an adapted scanning method on the scanning accuracy of a partially edentulous maxillary model., Material and Methods: The model simulated a maxilla with 6 prepared teeth to accommodate a complete arch fixed partial denture. Five ceramic precision balls (ball center P 1 -P 5 ), distributed buccally to the dental arch, were used to detect the dimensional and angular changes between the reference model and the intraoral scans. One intraoral scanner (Primescan) was used to make 30 scans each with either the scanning strategy recommended by the manufacturer (M) or with an adapted scanning strategy and the use of a bar (B) or 4 plates (P) as artificial landmarks in the dorsal palate. Data were statistically analyzed using a generalized least squares regression model (α=.05)., Results: Scanning with artificial landmarks reduced the maximum absolute distance deviations (M: 249 μm, B: 190 μm, P: 238 μm) and the maximum angle deviations (M: 0.31 degrees, B: 0.28 degrees, P: 0.26 degrees). Vertical distance deviations were improved by 10 to 50% with the use of artificial landmarks. Absolute mean distance deviations were significantly lower for group M (P<.001). In contrast, with artificial landmarks, mean angle (P<.001) and mean vertical distance deviations (P<.014) improved significantly., Conclusions: Scanning with artificial landmarks in the dorsal palate combined with an adapted scanning method improved the scanning accuracy and reliability of vertical distance deviations., (Copyright © 2022 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Studies are sparse on how splinting scan bodies or incorporating 3-dimensionally (3D) printed scan aids influence the trueness of complete arch digital scans., Purpose: The purpose of this in vitro study was to compare the trueness of multisite implant recordings obtained using 6 different methods on an edentulous mandible., Material and Methods: A definitive cast of an edentulous mandible with 4 multi-unit analogs placed at different angles and interanalog distances was extraorally scanned, and the resulting data were saved as a reference file. To obtain experimental files, 6 distinct methods were used: conventional impression with splinted open-tray impression copings (IC), intraoral scanning (IOS) without splinting scan bodies or using any scan aids (SB), IOS with pattern resin-splinted scan bodies (PR), IOS with composite resin-splinted scan bodies (CR), IOS with 3D printed custom scan bodies (CSB), and IOS with 3D printed auxiliary apparatus (AA). The experimental files were aligned to the reference file in a metrology software program. The 3D comparison algorithm was run to quantify the root mean square estimate error (RMS). Scan bodies in the files were converted to hollow virtual cylinders, and the Cartesian coordinates of the lines passing through the centers of these cylinders were recorded to analyze angular (AD) and linear distortion (LD). LD was further analyzed along the x (∆X), y (∆Y), and z axes (∆Z). One-way ANOVAs with the Tukey HSD test were used for statistical analysis (α=.05)., Results: AD at all sites, LD at all sites, and the RMS error showed significant differences (P<.05). The IC group showed the lowest AD values across all sites, followed by the AA, CSB, PR, CR, and SB groups. The SB group had the greatest LD values at all sites, while the IC group indicated the lowest LD values at all sites except the left anterior site. In terms of 3D distortions, the SB group had the largest RMS value, whereas the IC group showed the lowest RMS value. ∆X, ∆Y, and ∆Z values also showed significant differences at all sites (P<.001) except for the ∆Z values at the right anterior site (P=.194). The highest mean ∆X, ∆Y, and ∆Z values were recorded in the SB group except for the ∆Z measurement of the left posterior site., Conclusions: The IC group outperformed the other groups. The AA group exhibited distortion comparable with that of the IC group. Splinting scan bodies or using scan aids enhanced the trueness., (Copyright © 2024 Editorial Council for The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Introduction: The aim of this study was to evaluate the efficacy of different irrigation needles and passive ultrasonic activation in removing Ca(OH) 2 from an endodontic model that duplicated a root canal configuration of a human natural tooth., Methods: An extracted human maxillary premolar was subjected to root canal preparation and scanned with microcomputed tomography. A 3-dimensional reconstruction model of the natural tooth was printed to endodontic models using a polyjet printer. The root canals of the models were filled with Ca(OH) 2 paste and divided into 2 groups based on the irrigation protocol: conventional syringe-needle irrigation (conventional group) and passive ultrasonic irrigation (PUI) group. Each group was subdivided into 3 groups (n = 10) according to the type of needle: half-cut, side-vented, and TruNatomy irrigation needle. Microcomputed tomographyimaging was used to assess the percentage of reduction of Ca(OH) 2 . Data were analyzed using two-way analysis of variance test (α = .05)., Results: The side-vented and TruNatomy irrigation needles showed significantly higher percentage reductions than the half-cut needle (P < .05) in the conventional irrigation group. The PUI group showed significantly higher percentage reductions of Ca(OH) 2 than the conventional group regardless of the type of needle (P < .05). However, no significant difference was found among the needles in the PUI group., Conclusions: The type of irrigation needle and the use of PUI influenced the removal efficacy of Ca(OH) 2 . PUI enhanced the removal of Ca(OH) 2 regardless of the type of irrigation needle., (Copyright © 2024 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Aim: The aim of this study was to evaluate the accuracy of 3-dimensional (3D)-printed surgical guides for fully guided immediate implants from different manufacturers., Methods: Eighteen 3D printed fully guided surgical guides (split into 3 groups [n = 6] according to their manufacturer: Company, Desktop, or Lab), were used to place 72 implants (n = 24) in identical maxillary models. After placement, the mean global, angular, mesiodistal, buccopalatal, and vertical deviation at the platform and apex of the placed implants, relative to their preoperatively planned positions, was calculated., Results: Significant differences in global apex deviation, angular deviation, mesiodistal apex deviation, and vertical platform and apex deviation were found between the Lab and Desktop groups (p ≤ 0.007). Significant differences in mesiodistal platform and apex deviation and buccopalatal apex deviation were also found between the Company and Desktop groups (p ≤ 0.005). Finally, significant differences in buccopalatal apex deviation, and vertical platform and apex deviation were found between the Company and Lab groups (p ≤ 0.003). Mean differences between guide groups across all parameters never exceeded 0.5 mm or 1°., Conclusions: The choice of 3D printer has a significant effect on the accuracy of fully guided immediate implants. However, the clinical relevance of these differences may be considered limited., (© 2024 Wiley Periodicals LLC.)

Purpose: The purpose of this in vitro investigation was to assess how implant depth could affect the three-dimensional positional accuracy of digital impressions made from angulated implants., Materials and Methods: Four modified maxillary models were printed and divided into four study groups. In each model, two angulated implant analogs were placed at the sites of the first premolar and first molar at four different depths of 1 (G1), 2 (G2), 3 (G3), and 4 (G4) mm from the models' edentate area. Scan bodies were connected to the analogs, and one operator made 10 full-arch scans for each master model using an intraoral scanner. Afterward, the marginal gingival part of all models was removed, and digital scans were performed for each model using a laboratory scanner to achieve a reference STL file as the control group. One-way ANOVA and Leven's tests were used to measure and compare the 3D distance deviations across research groups after the superimposing test and control scans., Results: A significant difference between research groups was revealed by trueness and precision analysis (p < 0.001). The trueness and precision results obtained for G1 and G4 were significantly better than those for G2 and G3 (p < 0.05)., Conclusion: This study demonstrated that implant depth could affect the digital implant impressions' 3D positional accuracy., (© 2023 by the American College of Prosthodontists.)

Objective: To investigate changes in the upper maxillary palates of children with obstructive sleep apnoea (OSA) and mandibular retraction who were treated using modified twin-block appliances (MTBAs)., Methods: Thirty-five OSA children (age: 6-12 years) with mandibular retraction were included as the experimental group and 35 children who were Angle's class I but without mandibular retraction were included as the control group. The experimental group was treated with MTBA. Plaster models were made before the treatment and at the end of the 6-month treatment period. Plaster models of the control group were made at inclusion and after 6 months. Some plaster models were excluded because of damage or their failure to exhibit sufficiently clear marks, which left 26 pairs each for the experimental and control groups. The gender and age of the experimental group were matched with those of the control group at the end of the treatment. Three-dimensional (3D) digital model information was gathered using the external oral scanning model, and the data were extracted and analysed statistically to clarify the morphologic improvement in the maxillopalatine in OSA children treated using MTBAs., Results: After the OSA children with mandibular retraction were treated with MTBAs, the maxillary intercusp width, intermolar width, anterior palate width, posterior palate width, and surface area and volume of the maxillary palate significantly increased (*P < .05). By contrast, the anterior palatal height-apex level (H3) significantly decreased (*P < .05)., Conclusions: Compared with the control group, the narrow maxillary arch and basal bone were significantly enlarged after the OSA children with mandibular retraction were treated using MTBAs. The palatal surface area and volume increased, thereby allowing more space for accommodating the tongue and relieving transverse dissonance of the dentition., Competing Interests: Conflict of interest None disclosed., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

An esthetic peri-implant soft tissue contour is a critical element of the success of implant restorations in the esthetic zone. Once the optimal transmucosal soft tissue profile is formed, it needs to be accurately replicated on the master cast. This clinical technique involves the utilization of a silicone putty positioning index placed in the patient's mouth to accurately duplicate the external contour of teeth and soft tissue. By combining this positioning index with the implant-supported interim crown, the 3D-printed initial cast, which was used to fabricate the interim crown, can be conveniently and efficiently transformed into a definitive master cast., (© 2023 The Authors. Journal of Prosthodontics published by Wiley Periodicals LLC on behalf of American College of Prosthodontists.)

Objectives: To evaluate the trueness of dental arches digitised by two intraoral scanning (IOS) technologies from patients presenting crowding, diastema, and bilateral posterior edentulous space with tilted molar., Methods: Conventional impressions and dental stone models were generated from three patients presenting the aforementioned dental arch conditions. These models were digitised on a desktop scanner, and the resulting mesh was used as reference. Subsequently, the patients were scanned using confocal based (CF; iTero Element 2) and blue laser-multiscan (BLM; Virtuo Vivo) imaging IOS technology, totalling thirty scans. The meshes from the scans were exported in Standard Tessellation Language format and analysed using Geomagic Control X software. Root mean square (RMS) indicated deviation magnitude. Differences in IOS technologies were evaluated with paired t-tests, and dental arch conditions compared using ANOVA and post-hoc Tukey tests (α=0.05)., Results: Digital dental arch from blue laser-multiscan technology showed lower trueness compared to confocal based technology for crowding (p = 0.0084) and edentulous spaces (p = 0.0025) conditions. When the types of oral condition were compared, discrepancies were significantly different for both IOS technologies, featuring the arch with diastema showing the lowest trueness, followed by edentulous spaces and crowding., Conclusion: Dental arches presenting crowding and edentulous spaces digitised by blue laser-multiscan technology exhibited greater discrepancies compared to confocal based imaging technology. Furthermore, trueness varied among the dental arch conditions., Clinical Significance: The IOS technology and patient's dental arch condition can influence the trueness of dental arch digitisation. Being aware of these effects allows clinicians to take them into account during scanning procedures, digital planning and manufacturing., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Statement of Problem: Varying complete arch digital-implant-scanning techniques have been described, but their accuracy remains uncertain., Purpose: The purpose of this in vitro investigation was to assess the effect of the implant angulation and impression method (conventional, intraoral digital scan, intraoral scan with a splinting framework, and combining cone beam computed tomography [CBCT] and intraoral scan) on the accuracy of complete arch implant recording., Material and Methods: The following 2 casts were obtained: one with 4 parallel (P group) and the other with 4 angled (up to 30 degrees) implant abutment analogs (NP group). Both the casts were digitized (7Series Scanner) (control file). The following 4 subgroups were created: conventional polyether impression with a splinted framework (CNV subgroup), intraoral scan (IOS subgroup), intraoral scan with a splinting framework (S-IOS subgroup), and intraoral scan combined with CBCT scan (CBCT-IOS subgroup) (n=10). For each file, an implant-supported bar was designed and imported into a program (Netfabb) to perform linear and angular interimplant abutment measurements. Two-way ANOVA (Analysis of Variance) and Tukey tests were selected to examine the data (α=.05)., Results: Implant angulation (P=.010) and impression method (P=.003) significantly influenced the linear trueness. The P group (112 μm) obtained better linear trueness than the NP group (144 μm). The CNV subgroup obtained the best linear trueness, while the IOS and CBCT-IOS showed the worst trueness. Group (P<.001) significantly influenced angular trueness. Group (P=.009) and subgroup (P<.001) influenced the linear precision. The P group (72 μm) obtained better linear precision than the NP group (91 μm). The IOS subgroup obtained the best linear precision. Group (P=.034) significantly influenced the angular precision. The P group (0.46 degrees) had higher angular precision compared with the NP group (0.60 degrees)., Conclusions: Implant angulation and the impression methods tested, impacted the accuracy of the complete arch implant recording. Parallel implants had better trueness and precision values than nonparallel implants. The conventional impression method showed the best trueness and precision. Among the digital implant scan methods assessed, the S-IOS and CBCT-IOS subgroups acquired significantly better trueness and precision than the IOS subgroup., (Copyright © 2022 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Objective: To assess a newly developed intraoral scan protocol in enhancing the accuracy of complete-arch implant impressions., Materials and Methods: Four impression approaches were applied to the same maxillary edentulous model with 6 implants: (1) intraoral scan (IOS), (2) intraoral scan with scan aid (IOS-SA), (3) calibrated intraoral scan protocol (CISP), and (4) conventional splinted open-tray impression (CONV). Each approach was repeated 10 times, and a direct scan of the model with a desktop scanner was used as a reference model. The alignment of scans and the reference model was conducted by two methods: (a) aligning all scan bodies to evaluate the overall fit, and (b) aligning the first and second scan bodies to simulate the Sheffield fit test for passive fitting of multiple implant-supported prostheses. Linear deviations from the reference model (trueness) and within each group (precision) were analyzed using Python scripts., Results: When aligned by all scan bodies, the CISP group exhibited comparable mean trueness (38.33 μm) and precision (45.97 μm) to the CONV group (44.30 and 47.92 μm respectively), both of which significantly outperformed the IOS group (86.82 and 83.17 μm, respectively). Furthermore, in the virtual Sheffield fit test, the CISP group achieved the highest levels of mean trueness at the end span (121.7 μm), making a linear deviation reduction of 36.7%, 60%, and 41.4% when compared to the CONV, the IOS, and the IOS-SA groups, respectively. Moreover, the CISP group (104.3 μm) displayed a remarkable 65, 182, and 86 μm advantage in precision over the CONV, IOS, and IOS-SA groups, respectively., Conclusion: CISP demonstrated comparable accuracy to the gold standard, the conventional splinted open-tray impression. Furthermore, it excelled in the virtual passive fitting test., (© 2024 The Authors. Clinical Implant Dentistry and Related Research published by Wiley Periodicals LLC.)

Statement of Problem: Which method or material used to record the intercuspal position yields the best accuracy of location of the maxillary and mandibular casts is unclear., Purpose: The purpose of this clinical study was to determine the most reliable method of recording a patient's maximal intercuspal position by comparing 2 common methods with 2 popular registration materials., Material and Methods: Complete arch impressions were made of both jaws with a polyvinyl siloxane impression material in a metal stock tray followed by 4 interocclusal registrations for each of the 17 participants. Two registration techniques were used. More than 1 record was obtained in the first technique, as the participant had to close through a wax sheet or a polyvinyl siloxane material. In the second technique, a polyvinyl siloxane material was injected from the buccal aspect between occluded tooth surfaces. Casts were made from Type 4 stone and vertical measurements of the casts were carried out by using digital vernier calipers, accurate to 100 μm. Hand articulation of the casts was used as the control. Consistency of measurement was assessed by the intraclass correlation coefficient, and comparisons were made by using repeated-measures regression analysis., Results: Statistical analysis showed significant discrepancies when the participant closed through both wax and polyvinyl siloxane material (P<.001). No statistically significant differences to the control group were present when polyvinyl siloxane was injected laterally after closure., Conclusions: Hand articulation was the most accurate method of reproducing the maximal intercuspal position in a completely dentate individual with horizontal and vertical occlusal stability and was therefore considered the control. Recording the position after the participant had closed by using a polyvinyl siloxane material was the most accurate., (Copyright © 2022 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Introduction: Research regarding orthodontic changes using the superimposition of digital study models (DSMs) is commonplace. Information regarding the accuracy of data processing by superimposition software is limited. The study aimed to compare different methods of superimposing DSMs using implant-supported crowns (ISC) as a stable reference structure., Methods: DSMs containing ISCs were sourced from a database of patients treated with clear aligner therapy. The DSM representing the planned treatment outcome was superimposed on the pretreatment DSM. Three tooth points were selected for comparison on the contralateral side of each ISC. Differences in Cartesian coordinates for each tooth point for each arch superimposition method, used by the Geomagic Control X (3D systems, Rock Hill, NC) software system, were recorded. Paired t tests for the reference standard superimposition method best-fit high-resolution using the entire dental arch compared with initial, best-fit low-resolution, and best-fit high-resolution using the ISC only were calculated., Results: The DSMs of 54 dental arches containing ISCs were evaluated. All mean differences for displacements of selected points on the contralateral side to the ISC in the 3 Cartesian planes were <0.05 mm (P <0.05) and below the threshold of clinical significance. In addition, the standard superimposition techniques (initial, best-fit low-resolution, and best-fit high-resolution) resulted in nonstatistically significant and nonclinically significant differences in the position of the ISC., Conclusions: Researchers can be confident that the described superimposition methodologies, with and without ISCs as a stable reference structure, are a valid method for accurately assessing most intraarch dental changes., (Copyright © 2024 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: The use of digital interocclusal registration scans for virtual articulation and mounting has been studied extensively; however, the accuracy of the cross-mounting procedures in a digital workflow is not well understood., Purpose: The purpose of this in vitro study was to compare the accuracy of digital and conventional cross-mounting by measuring the 3-dimensional deviation at each step of sequential cross-mounting., Material and Methods: A set of reference casts and complete arch interim restorations was prepared for complete arch complete-coverage restorations, hand-articulated, and mounted in an articulator. The reference casts were then scanned with and without the interim restorations to generate 4 reference casts for cross-mounting. For the conventional group, 15 sets of the 4 casts were printed. Polyvinyl siloxane interocclusal registration records were made of the reference casts for each set, and casts were sequentially cross-mounted. For the digital workflow, 15 sets of bilateral interocclusal registration scans were made of the mounted reference casts and used to align the cast scans. Three-dimensional deviations at 2 anterior and 2 posterior points were recorded between the experimental mountings and the reference casts on each set of casts. Nonpaired t test and analysis of variance (ANOVA) were used to compare the average discrepancy between the 2 groups, and the pooled anterior versus posterior discrepancies were compared (α=.05)., Results: A significant difference was found between conventional and digital cross-mounting procedures (P<.001), but no significant difference was found in either group, conventional (P=.116) or digital (P=.987), at each step of the sequential mountings. The mean ±standard deviation at the final set of related casts in the conventional workflow was 201.6 ±137.0 μm and that in the digital group was 50.3 ±47.5 μm, with a significant difference between anterior and posterior deviations in the digital group (P=.028), but not in the conventional group (P=.143). The mean ±standard deviation anterior conventional deviation was 175.6 ±119.2 μm and that in the digital group was 36.9 ±30.9 μm. The mean ±standard deviation posterior conventional deviation was 227.6 ±50.2 μm and that in the digital group was 63.7 ±57.2 μm., Conclusions: Digital cross-mounting was more accurate than conventional cross-mounting, although increased deviation was found in the anterior region compared with the posterior region., (Copyright © 2022 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)