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Purpose: Dental implants are a common treatment method after tooth loss, the accuracy of which directly affects efficacy and stability. Through a network meta-analysis, this study compared the accuracy of different modalities of implant placement: dynamic navigation (DN), fully guided static navigation (FG), partially guided static navigation (PG), and free handed (FH). Materials and Methods: This study followed the Preferred Reporting Items for Meta-Analyses (PRISMA) guidelines. An electronic literature search was conducted on October 2, 2022. The comparison of implant accuracy in all included randomized controlled trials (RCTs) conformed to at least one of the following: deviation at the implant crown, deviation at the apical portion of the implant, or angular deviation of the implant. Results: Twenty-six articles were included for the qualitative analysis (17 RCTs, 3 prospective studies, and 6 retrospective studies), and the 17 RCTs were included for network meta-analysis. The data included in this study had high consistency, and the funnel plot showed that the articles had low publication bias. Compared to FH, FG and DN had higher accuracy for coronal deviation (P < .05), and FG, DN, and PG had higher accuracy for apical and angular deviations (P < .05). According to the SUCRA (surface under the cumulative ranking curves) value, FG had the highest accuracy for coronal deviation, while DN had the highest accuracy in apical and angular deviations. Conclusions: According to the present results, the accuracies for DN, FG, and PG were higher than those for FH. DN showed the highest accuracy in terms of apical deviation and angular deviation. FG had the best control over the coronal deviation. There was no statistical difference between DN and FG in terms of accuracy. Given the limitations of the current study, further validation is required. [ABSTRACT FROM AUTHOR]

Objective: This study compared the dimensional accuracy of two polyvinyl siloxane putty-wash impression techniques with the digital impression method for single implants adjacent to tooth crown preparations. Methods: Impressions were taken from a dental arch containing a full-metal preparation on the first molar adjacent to a Straumann tissue-level implant at the second premolar site. A laboratory scanner generated a standard tessellation language (STL) file as the reference for comparisons. Three methods were tested, each performed 10 times: (1) one-step putty-wash technique, (2) two-step putty-wash technique, and (3) digital impressions. Dimensional accuracy was assessed by measuring overall die dimensions, die height, die width, and the tooth-implant distance, using Geomagic Wrap software. Statistical analyses included one-way ANOVA and the Kruskal-Wallis test, with significance at P < 0.05. Results: No significant differences were found among the methods for the die height (P = 0.130), die width (P = 0.180), and tooth-implant distance (P = 0.486). However, the digital impression method showed significantly greater overall dimensional accuracy than the one-step putty-wash technique (P = 0.004). The two-step putty-wash method showed no significant difference with the one-step method or digital impressions concerning the overall die accuracy (P > 0.05). Conclusions: Digital impressions demonstrated significantly higher overall dimensional accuracy than the one-step putty-wash technique. Die height, die width, and tooth-implant distance were comparable across methods. Digital impressions are recommended for optimal accuracy when taking impressions from single implants adjacent to tooth crown preparations. The two-step putty-wash method offers a reliable alternative when digital tools are unavailable. [ABSTRACT FROM AUTHOR]

Objective: This study compared the dimensional accuracy of two polyvinyl siloxane putty-wash impression techniques with the digital impression method for single implants adjacent to tooth crown preparations.Methods: Impressions were taken from a dental arch containing a full-metal preparation on the first molar adjacent to a Straumann tissue-level implant at the second premolar site. A laboratory scanner generated a standard tessellation language (STL) file as the reference for comparisons. Three methods were tested, each performed 10 times: (1) one-step putty-wash technique, (2) two-step putty-wash technique, and (3) digital impressions. Dimensional accuracy was assessed by measuring overall die dimensions, die height, die width, and the tooth-implant distance, using Geomagic Wrap software. Statistical analyses included one-way ANOVA and the Kruskal-Wallis test, with significance at P < 0.05.Results: No significant differences were found among the methods for the die height (P = 0.130), die width (P = 0.180), and tooth-implant distance (P = 0.486). However, the digital impression method showed significantly greater overall dimensional accuracy than the one-step putty-wash technique (P = 0.004). The two-step putty-wash method showed no significant difference with the one-step method or digital impressions concerning the overall die accuracy (P > 0.05).Conclusions: Digital impressions demonstrated significantly higher overall dimensional accuracy than the one-step putty-wash technique. Die height, die width, and tooth-implant distance were comparable across methods. Digital impressions are recommended for optimal accuracy when taking impressions from single implants adjacent to tooth crown preparations. The two-step putty-wash method offers a reliable alternative when digital tools are unavailable.

The transfer of a virtual orthognathic surgical plan to the patient still relies on the use of occlusal splints, which have limitations for vertical positioning of the maxilla. The use of real-time navigation has been proposed to enhance surgical accuracy. This systematic review (PROSPERO CRD42024497588) aimed to investigate if surgical navigation can improve the three-dimensional accuracy of orthognathic surgery. The inclusion criteria were orthognathic surgery, use of intra-operative navigation and quantitative assessment of surgical accuracy. The exclusion criteria were non-bimaxillary orthognathic surgeries, non-clinical studies, studies without post-operative 3D analysis and publications not in the English language. A search of PubMed, Embase and Cochrane Library generated 940 records, of which 12 were found relevant. Risk of bias was assessed done using the Joanna Briggs Institute Critical Appraisal Checklist Tool. Among the included studies, there were nine of observational character and three randomized control studies (RCTs). All studies demonstrated promising outcomes with reported good surgical accuracy within a 2 mm difference between the planned and post-surgical result. Meta-analysis of two RCTs was carried out and results were in favor of surgical navigation with a total odds ratio of 4.44 [2.11, 9.37] and an overall effect outcome of Z = 3.92 (p < 0.0001). Navigation was up to 0.60 mm more accurate than occlusal wafers only (p < 0.001). However, there were variations in the application of surgical navigation and methods of analysis, leading to a heterogenous data set. Future studies should focus on standardized protocols and analysis methods to further validate the use of surgical navigation in orthognathic surgery. Despite some limitations, surgical navigation shows potential as a valuable tool in improving the accuracy of orthognathic surgery. [ABSTRACT FROM AUTHOR]

Background: With the rise of new 3D printers, assessing accuracy is crucial for obtaining the best results in patient care. Previous studies have shown that the highest accuracy is achieved with SLS printing technology; however, SLA printing technology has made significant improvements in recent years. Methods: In this study, a realistic anatomical model of a mandible and skull, a cutting guide for mandibular osteotomy, and a splint for orthognathic surgery were replicated five times each using two different 3D printing technologies: SLA and SLS. Results: The SLA group had a median trueness RMS value of 0.148 mm and a precision RMS value of 0.117 mm. The SLS group had a median trueness RMS value of 0.144 mm and a precision RMS value of 0.096 mm. There was no statistically significant difference in RMS values between SLS and SLA technologies regarding trueness. Regarding precision, however, the RMS values for SLS technology were significantly lower in the splint and cutting guide applications than those printed with SLA technology. Conclusions: Both 3D printing technologies produce modern models and applications with equally high dimensional accuracy. Considering current cost pressures experienced by hospitals, the lower-cost SLA 3D printer is a reliable choice for point-of-care 3D printing. [ABSTRACT FROM AUTHOR]

Purpose: To explore the clinical application of one‐piece polyetheretherketone (PEEK) removable partial dentures (RPDs) fabricated using a novel digital workflow and to evaluate their weights and fits in vivo and patient satisfaction. Materials and Methods: Fifteen cases with posterior partially edentulous situations were selected, and each patient received two types of RPDs, including a novel digital workflow (test group) and a conventional workflow (control group). For the test group, one‐piece RPDs were designed through three‐dimensional (3D) methods by scanning stone casts and fabricated by milling PEEK discs. Each RPD was weighed. The gaps between the oral tissue and RPDs in each group were duplicated using a polyvinylsiloxane (PVS) replica and measured by 3D analysis. A visual analog scale (VAS) was used to evaluate the patient's satisfaction. Paired t‐tests were used to compare the differences in the weight, the gaps of each RPD, and VAS values between the two groups. One‐way analysis of variance tests was used to compare the differences in the gap among different components in each group. Results: The RPD in the test group weighed less than that in the control group (p < 0.01). No statistically significant differences in the gaps of denture bases and rests (p > 0.05) were found between the two groups, but the gaps of major connectors in the test group were significantly smaller than in the control group (p < 0.05). The VAS scores for comfortableness and masticatory efficiency were not significantly different between the two groups (p > 0.05) but the scores for the aesthetic appearance of the clasps in the test group were significantly higher than that in the control group (p < 0.05). Conclusions: One‐piece PEEK RPDs manufactured using a novel digital workflow weighed less than conventional RPDs and exhibited a clinically acceptable internal fit. Although the aesthetic appearance of the PEEK clasps was superior to the control, there is still room for improvement. [ABSTRACT FROM AUTHOR]

Purpose: The aim was to analyze the accuracy of digital models and 3D-printed casts from full-arch digital impressions using two intraoral scanners (iTeroTM and PrimescanTM). Materials and methods: A crossover reliability study was designed, scanning children and teenagers with iTeroTM and PrimescanTM. Accuracy was evaluated by measuring intercanine, intermolar, and ipsilateral canine–molar distances intraorally and comparing these measurements with those from plaster casts, digital models obtained with intraoral scanners, and 3D-printed casts. A paired comparison and a general linear model with a one-way repeated measures ANOVA procedure were carried out with a confidence level of 95% (p ≤ 0.05). Results: A total of 51 subjects were analyzed (mean age 12.35 ± 2.57). Statistical differences (p < 0.05) were found in the upper and lower arch regarding accuracy in comparison to intraoral measurements, except for the iTeroTM-printed cast and canine–molar upper right and intercanine lower distances (p > 0.05 for all comparisons). Regarding a comparison between reproduction methods, the plaster cast oversized the intercanine upper distance in comparison with both intraoral scanners' digital models and the PrimescanTM-printed cast (p = 0.001), but there were no differences in the lower arch (p > 0.05 for all comparisons). Conclusion: Intraoral scanners reproduce tooth structures with similar accuracy to conventional methods. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Orofacial Orthopedics/Fortschritte der Kieferorthopadie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background/Objective: With the rapid advancement in surgical technologies, new workflows for mandibular reconstruction are constantly being evaluated. Cutting guides are extensively employed for defining osteotomy planes but are prone to errors during fabrication and positioning. A virtually defined osteotomy plane and drilling holes in robotic surgery minimize potential sources of error and yield highly accurate outcomes. Methods: Ten mandibular replicas were evaluated after cutting-guided saw osteotomy and robot-guided laser osteotomy following reconstruction with patient-specific implants. The descriptive data analysis summarizes the mean, standard deviation (SD), median, minimum, maximum, and root mean square (RMS) values of the surface comparison for 3D printed models regarding trueness and precision. Results: The saw group had a median trueness RMS value of 2.0 mm (SD ± 1.7) and a precision of 1.6 mm (SD ± 1.4). The laser group had a median trueness RMS value of 1.2 mm (SD ± 1.1) and an equal precision of 1.6 mm (SD ± 1.4). These results indicate that robot-guided laser osteotomies have a comparable accuracy to cutting-guided saw osteotomies, even though there was a lack of statistical significance. Conclusions: Despite the limited sample size, this digital high-tech procedure has been shown to be potentially equivalent to the conventional osteotomy method. Robotic surgery and laser osteotomy offers enormous advantages, as they enable the seamless integration of precise virtual preoperative planning and exact execution in the human body, eliminating the need for surgical guides in the future. [ABSTRACT FROM AUTHOR]

Purpose: Preoperative planning has become essential in performance of total hip arthroplasty (THA). However, data regarding the effect of the planner's experience on the accuracy of digital preoperative planning is limited. The objective of this study was to assess the accuracy of digital templating in THA based on the surgeon's experience. Materials and Methods: A retrospective study was conducted. An analysis of 98 anteroposterior pelvic radiographs, which were individually templated by four surgeons (two hip surgeons and two orthopaedic residents) using TraumaCad® digital planning, was performed. A comparison of preoperatively planned sizes with implanted sizes was performed to evaluate the accuracy of predicting component size. The results of preoperative planning performed by hip surgeons and orthopaedic residents were compared for testing of the planner's experience. Results: Femoral stem was precisely predicted in 32.4% of cases, acetabular component in 40.3%, and femoral offset in 76.7%. Prediction of cup size showed greater accuracy than femoral size among all observers. No differences in any variable were observed among the four groups (acetabular cup P =0.07, femoral stem P =0.82, femoral offset P =0.06). All measurements showed good reliability (intraclass correlation coefficient [ICC] acetabular cup: 0.76, ICC femoral stem: 0.79). Conclusion: The results of this study might suggest that even though a surgeon's experience supports improved precision during the planning stage, it should not be restricted only to surgeons with a high level of experience. We consider preoperative planning an essential part of the surgery, which should be included in training for orthopaedics residents. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to determine if different types of core substrates have any effect on the trueness and precision of digital intraoral impressions. Material and Methods: A customized typodont with four similar cores of natural dentine, composite, metal (Ni‐Cr), and zirconia in the position of premolars was fabricated. The study model was scanned five times with two types of intraoral scanners (Carestream 3600 and 3Shape Trios 3), and a reference standard scan was obtained using a laboratory scanner (3shape D1000). A metrology software (Geomagic X) was used to align the data of experimental scans and the reference scan to determine deviation values (trueness). Precision values were calculated with random superimposition in each intraoral scanner group. The Kruskal–Wallis test was used to compare differences between different substrates, and the Mann–Whitney test was used to compare the average values between the two scanners. Results: Trios 3 was found to be significantly truer and more precise than Carestream 3600 (p value =.005, <0.001). There were no significant differences in the trueness of different substrates when they were scanned by Trios 3, while different materials showed significantly different trueness values in the Carestream 3600 group (p value =.003). Dentin showed the best trueness, and zirconia performed worse than other substrates. Regarding the precision of the scanners, neither of the scanners was affected by the type of scanning substrate. Conclusion: For Carestream 3600, substrate type did impact the trueness of intraoral scans, with dentin and zirconia showing the highest and lowest accuracy, respectively, while Trios 3 was similarly accurate across all substrates. Trios 3 had both higher trueness and precision than Carestream 3600. [ABSTRACT FROM AUTHOR]

Objective: To determine the relationship between skeletal malocclusion and upper pharyngeal airway space in the United Arab Emirates population using linear cephalometric measurements. Material and Methods: A retrospective cross-sectional study was performed on lateral cephalogram radiographs acquired from the University Dental Hospital. Through convenience sampling, 70 lateral cephalograms were selected from 200, meeting the inclusion criteria for this study. Study subjects were divided into three groups: Class I (n=25), Class II (n=21), and Class III (n=24). The study groups were compared based on the linear upper pharyngeal airway space measurements. Results: The three groups observed significant differences between the upper pharyngeal airway measurements. No differences in parameters were noted within the male and female study subjects. A highly significant difference (p

Purpose: The aim of this study is to develop and validate a case study to aid in the diagnostic reasoning of nursing students and nurses. Methods: It is a validation study using a case study based on Lunney's method including (1) content validation of the case study by nurse experts through the Delphi technique, (2) identification of nursing diagnoses (NDs) in the case, (3) evaluation of diagnostic accuracy, and (4) establishment of a priority diagnosis by nurse experts. Findings: The case study was developed from the findings of a narrative literature review on the cues of the NDs with a prevalence > 50% in patients with peripheral arterial occlusive disease. Two rounds of expert evaluation were required to validate the case study. The experts identified 18 NDs with different degrees of accuracy. The highly accurate diagnoses most frequently identified by the experts were: Ineffective peripheral tissue perfusion (100%), impaired walking (83%), impaired comfort (50%), and chronic pain (50%). The diagnosis considered a priority by all experts was ineffective peripheral tissue perfusion. Conclusions: The case study was developed and had its content validated. High‐accuracy diagnoses were identified, and a priority was determined. Implications for Nursing Practice: The validated case study may be used by students and nurses to facilitate the development of diagnostic reasoning and critical thinking in practice, teaching or research. [ABSTRACT FROM AUTHOR]

Objectives: Limited studies are available on the accuracy of intraoral scanners (IOSs) for full‐arch implant and tooth models. This study aimed to assess the accuracy of maxillary full‐arch digital impressions of tooth and implant models made by two IOSs. Materials and Methods: This in vitro, experimental study was conducted on two maxillary dentiform models: one with six prepared natural teeth and the other with six implants at the site of canine, first premolar, and first molar teeth, bilaterally. A highly accurate industrial scanner was used for actual measurements on the models that served as the reference scan. TS (Trios3) and CO (CEREC Omnicam) IOSs were then used to scan each model 10 times according to the manufacturer's instructions. All scans were saved in STL format. The GOM Inspect software was used according to the best‐fit algorithm to compare the accuracy of measurements in the groups with the reference scan. The trueness and precision were calculated. Statistical analyses were carried out using SPSS by one‐way analysis of variance and t‐test (α =.05). Results: TS showed a significantly higher trueness than CO for both tooth and implant models (p <.05). TS also revealed significantly higher precision than CO for the tooth model; however, the difference in precision for the implant model was not significant between the two IOSs (p >.05). Conclusions: TS showed higher accuracy than CO in both tooth and implant models. [ABSTRACT FROM AUTHOR]

Copyright of International Journal of Computerized Dentistry is the property of Quintessence Publishing Company Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Background The aim of this study was to determine if different types of core substrates have any effect on the trueness and precision of digital intraoral impressions. Material and Methods A customized typodont with four similar cores of natural dentine, composite, metal (Ni‐Cr), and zirconia in the position of premolars was fabricated. The study model was scanned five times with two types of intraoral scanners (Carestream 3600 and 3Shape Trios 3), and a reference standard scan was obtained using a laboratory scanner (3shape D1000). A metrology software (Geomagic X) was used to align the data of experimental scans and the reference scan to determine deviation values (trueness). Precision values were calculated with random superimposition in each intraoral scanner group. The Kruskal–Wallis test was used to compare differences between different substrates, and the Mann–Whitney test was used to compare the average values between the two scanners. Results Trios 3 was found to be significantly truer and more precise than Carestream 3600 (p value = .005,

Purpose: The aim was to analyze the accuracy of digital models and 3D-printed casts from full-arch digital impressions using two intraoral scanners (iTeroTM and PrimescanTM). Materials and methods: A crossover reliability study was designed, scanning children and teenagers with iTeroTM and PrimescanTM. Accuracy was evaluated by measuring intercanine, intermolar, and ipsilateral canine–molar distances intraorally and comparing these measurements with those from plaster casts, digital models obtained with intraoral scanners, and 3D-printed casts. A paired comparison and a general linear model with a one-way repeated measures ANOVA procedure were carried out with a confidence level of 95% (p ≤ 0.05). Results: A total of 51 subjects were analyzed (mean age 12.35 ± 2.57). Statistical differences (p < 0.05) were found in the upper and lower arch regarding accuracy in comparison to intraoral measurements, except for the iTeroTM-printed cast and canine–molar upper right and intercanine lower distances (p > 0.05 for all comparisons). Regarding a comparison between reproduction methods, the plaster cast oversized the intercanine upper distance in comparison with both intraoral scanners’ digital models and the PrimescanTM-printed cast (p = 0.001), but there were no differences in the lower arch (p > 0.05 for all comparisons). Conclusion: Intraoral scanners reproduce tooth structures with similar accuracy to conventional methods.

Objective The objective of this study was to evaluate the accuracy of pedicle screw placement in patients undergoing percutaneous pedicle screw fixation with robotic guidance, using a newly developed 3-dimensional quantitative measurement system. The study also aimed to assess the clinical feasibility of the robotic system in the field of spinal surgery. Methods A total of 113 patients underwent pedicle screw insertion using the CUVIS-spine pedicle screw guide system (CUREXO Inc.). Intraoperative O-arm images were obtained, and screw insertion pathways were planned accordingly. Image registration was performed using paired-point registration and iterative closest point methods. The accuracy of the robotic-guided pedicle screw insertion was assessed using 3-dimensional offset calculation and the Gertzbein-Robbins system (GRS). Results A total of 448 screws were inserted in the 113 patients. The image registration success rate was 95.16%. The average error of entry offset was 2.86 mm, target offset was 2.48 mm, depth offset was 1.99 mm, and angular offset was 3.07°. According to the GRS grading system, 88.39% of the screws were classified as grade A, 9.60% as grade B, 1.56% as grade C, 0.22% as grade D, and 0.22% as grade E. Clinically acceptable screws (GRS grade A or B) accounted for 97.54% of the total, with no reported neurologic complications. Conclusion Our study demonstrated that pedicle screw insertion using the novel robot-assisted navigation method is both accurate and safe. Further prospective studies are necessary to explore the potential benefits of this robot-assisted technique in comparison to conventional approaches.

Abstract Objectives Limited studies are available on the accuracy of intraoral scanners (IOSs) for full‐arch implant and tooth models. This study aimed to assess the accuracy of maxillary full‐arch digital impressions of tooth and implant models made by two IOSs. Materials and Methods This in vitro, experimental study was conducted on two maxillary dentiform models: one with six prepared natural teeth and the other with six implants at the site of canine, first premolar, and first molar teeth, bilaterally. A highly accurate industrial scanner was used for actual measurements on the models that served as the reference scan. TS (Trios3) and CO (CEREC Omnicam) IOSs were then used to scan each model 10 times according to the manufacturer's instructions. All scans were saved in STL format. The GOM Inspect software was used according to the best‐fit algorithm to compare the accuracy of measurements in the groups with the reference scan. The trueness and precision were calculated. Statistical analyses were carried out using SPSS by one‐way analysis of variance and t‐test (α = .05). Results TS showed a significantly higher trueness than CO for both tooth and implant models (p .05). Conclusions TS showed higher accuracy than CO in both tooth and implant models.

Purpose: To assess the accuracy of scanning technologies for constructing facial prostheses on human faces. Study selection: Our systematic search was performed on five databases. Studies reporting on human volunteers (P) whose faces were scanned with a scanning technology were eligible. The anthropometrical interlandmark distances (ILDs) were used as indicators of accuracy; the ILDs are measured on the virtual models (I) and directly on the faces (C). The virtual models deviated from their true values (O). Studies reporting the measurements on patients with or without facial deformities were included, but cadavers or inanimate objects were reasons for exclusion. We performed a mean difference (MD) / standardized MD analysis with a random effect model. The difficulties regarding the scanning procedure mentioned in the articles were also assessed. Results: We found 3723 records after duplicate removal. Twenty five articles were eligible for the qualitative review, and ten articles were included in the quantitative synthesis. Eight different ILDs were compared in MD analyses. The differences were between -0.54-0.43 mm. We also performed a regional three-dimensional analysis to compare scanning technologies in each major region. No significant differences were found in any of the regions and axes. The most mentioned difficulties were artifacts due to motion or blinking. Conclusions: The results suggest no systematic skew in linear dimensions neither between direct caliper measurements nor between measurements on the scanned models, scanning technologies, or facial regions. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study was to evaluate and compare the accuracy and image quality of root surface area (RSA) measurements obtained with various cone-beam computed tomography (CBCT) protocols, relative to the gold standard of micro-computed tomography (CT), in an in vitro setting. Materials and Methods: Four dry human skulls were scanned using 8 different protocols, with voxel sizes of 0.15 mm, 0.3 mm, and 0.4 mm. Three-dimensional models of the selected teeth were constructed using CBCT and micro-CT protocols, and the RSA was automatically measured by the image-processing software. The absolute difference in the percentage of the RSA (%ΔRSA) was calculated and compared across the 8 CBCT protocols using repeatedmeasures analysis of variance. Finally, image quality scores of the RSA measurements were computed and reported in terms of percent distribution. Results: No significant differences were observed in the %ΔRSA across the 8 protocols (P>0.05). The deviation in %ΔRSA ranged from 1.51% to 4.30%, with an increase corresponding to voxel size. As the voxel size increased, the image quality deteriorated. This decline in quality was particularly noticeable at the apical level of the root, where the distribution of poorer scores was most concentrated. Conclusion: Relative to CBCT protocols with voxel sizes of 0.15 mm and 0.3 mm, the protocols with a voxel size of 0.4 mm demonstrated inferior image quality at the apical levels. In spite of this, no significant discrepancies were observed in RSA measurements across the different CBCT protocols. [ABSTRACT FROM AUTHOR]

Abstract Background Three-dimensional (3D) printing is a novel innovation in the field of craniomaxillofacial surgery, however, a lack of evidence exists related to the comparison of the trueness of skull models fabricated using different technology-based printers belonging to different cost segments. Methods A study was performed to investigate the trueness of cone-beam computed tomography-derived skull models fabricated using different technology based on low-, medium-, and high-cost 3D printers. Following the segmentation of a patient’s skull, the model was printed by: (i) a low-cost fused filament fabrication printer; (ii) a medium-cost stereolithography printer; and (iii) a high-cost material jetting printer. The fabricated models were later scanned by industrial computed tomography and superimposed onto the original reference virtual model by applying surface-based registration. A part comparison color-coded analysis was conducted for assessing the difference between the reference and scanned models. A one-way analysis of variance (ANOVA) with Bonferroni correction was applied for statistical analysis. Results The model printed with the low-cost fused filament fabrication printer showed the highest mean absolute error ( $$1.33\pm 0.24 \text{mm}$$ 1.33 ± 0.24 mm ), whereas both medium-cost stereolithography-based and the high-cost material jetting models had an overall similar dimensional error of $$0.07\pm 0.03 \text{mm}$$ 0.07 ± 0.03 mm and $$0.07\pm 0.01 \text{mm}$$ 0.07 ± 0.01 mm , respectively. Overall, the models printed with medium- and high-cost printers showed a significantly ( $$p

Abstract Purpose To compare the accuracy of five different tooth‐implant impression techniques. Materials and Methods In this in vitro, experimental study, an acrylic model containing one bone‐level Straumann dental implant at the site of maxillary first molar and an adjacent second premolar prepared for a porcelain fused to metal restoration was used. Impressions were made from the model using five different one‐step tooth‐implant impression techniques including scanning with an intraoral scanner, occlusal matrix, wax relief, closed‐tray, and open‐tray techniques. Each technique was repeated 15 times. The impressions were poured with dental stone, and the obtained casts were scanned by a laboratory scanner. The scan file of each technique was compared with the scan file of the original acrylic model by Geomagic Design X software. Data were analyzed by one‐way analysis of variance, and Tamhane's post‐hoc test (α = 0.05). Results For dental implant, intraoral scanning had the highest accuracy (0.1004 mm2) followed by open‐tray (0.1914 mm2), occlusal matrix (0.2101 mm2), closed‐tray (0.2422 mm2), and wax relief (0.2585 mm2) techniques (p 0.05). Conclusion The compared simultaneous tooth‐implant impression techniques had comparable accuracy with no significant difference.

Abstract Objectives The effect of head position on reproducibility of volumetric measurements on Cone‐beam computed tomography (CBCT) scans has not been evaluated before. Thus, this study aimed to assess the changes in linear and volumetric measurements on CBCT scans in different positions of the respective object. Materials and methods In this experimental study, 16 balls were placed in containers and underwent CBCT in neutral position and 8 different altered positions. The horizontal and vertical diameters of each ball were measured by OnDemand software while the volume of each ball was quantified by ITK‐Snap software. The reproducibility of linear and volumetric measurements in nine different positions was analyzed by the Cronbach's α. Paired t‐test was applied to analyze the difference in volumetric and linear measurements of the balls in the anterior and posterior halves of the scans in neutral position versus the upward and downward tilts, and right and left halves of the scans in neutral position versus the right and left tilts. Results The Cronbach's α was found to be .982 and .933 for volumetric and linear measurements, respectively, indicating high reproducibility of the measurements. No significant difference was noted in the mean linear measurements on CBCT scans at different positions compared with neutral position. In volumetric measurements, maximum difference between neutral and the other positions was less than 1%. Conclusions CBCT is a reliable modality for linear and volumetric measurements in different positions.

Introduction: We aim to determine and compare the correlation between conventional and digital impression methods for measuring mesiodistal teeth dimensions. Methods: This cross-sectional analytical study was conducted on a total of 120 dental arch samples with less than 5 mm of tooth crowding, complete teeth on the dental arch, no missing teeth, and no fillings on the mesial or distal sides at Can Tho University of Medicine and Pharmacy. Conventional (extra-fast alginate) and digital impressions using a 3D intraoral scanner (CEREC Primescan) were taken from all participants, and the dimensions of the mesiodistal teeth were measured. Using R software, Pearson's correlation coefficients were used to analyze the correlation between conventional and digital impression methods. Result: The pooled correlation for the maxilla was 0.8062 [95% confidence interval (CI): 0.7751-0.8334] (very strong positive correlation); for the mandibular, it was 0.7645 (95% CI: 0.7165-0.8054) (strong positive correlation), and for both jaws was 0.7863 (95% CI: 0.7581-0.8115) (strong positive correlation). Conclusion: In the Vietnamese population measurement of mesiodistal tooth width using a digital dental scanner can be used instead of conventional plaster models. [ABSTRACT FROM AUTHOR]

Blood pressure (BP) is the main biomarker for monitoring patients, as its lack of control above values considered normal is a modifiable risk factor for target organ damage. The aim of this study is to evaluate the accuracy of the wearable electronic device photoplethysmography technology (PPG) Samsung Galaxy Watch 4 in determining BP in young patients compared to manual and automatic methods of BP determination. This is a quantitative and cross-sectional study, following validation protocols for wearable devices and BP measurement. It was carried out with twenty healthy young adults, in which BP was measured using four instruments, namely, standard sphygmomanometer device (manual), automatic arm oscillometric device (reference), wrist oscillometric device, and Smartwatch PPG. Eighty systolic blood pressure (SBP) and diastolic blood pressure (DBP) readings were observed. SBP means manual 118 ± 2.20,arm 113 ± 2.54, wrist 118 ± 2.51, and PPG (smartwatch) 113 ± 2.58. Among means, arm and PPG difference is 0.15, arm and wrist 4.95, arm and manual 4.45 wrist with PPG. The mean DBP manual 76.7 ± 1.84, arm 73.6 ± 1.92, wrist 79.3 ± 1.87, and PPG 72.2 ± 1.38. Among means, the difference between the arm and PPG is 1.4 and arm and hand 3.5 mmHg. The correlation shows PPG with manual, arm, and wrist. There was a strong SBP correlation and a moderate DBP correlation between the methods tested, evidencing the accuracy of the PPG smartwatch in relation to the reference method. [ABSTRACT FROM AUTHOR]

The accurate assessment of wound size is a critical step in advanced wound care management. This study aims to introduce and validate a Light Detection and Ranging (LiDAR) technique for measuring wound size. Twenty-eight wounds treated from December 2022 to April 2023 at the Chungnam National University Hospital were analyzed. All the wounds were measured using three techniques: conventional ruler methods, the LiDAR technique, and ImageJ analysis. Correlation analysis, linear regression, and Bland–Altman plot analysis were performed to validate the accuracy of the novel method. The measurement results (mean ± standard deviation) obtained using the ruler method, LiDAR technique, and ImageJ analysis were 112.99 ± 110.07 cm2, 73.59 ± 72.97 cm2, and 74.29 ± 72.15 cm2, respectively. The Pearson correlation coefficient was higher for the LiDAR application (0.995) than for the conventional ruler methods (mean difference, −5.0000 cm2), as was the degree of agreement (mean difference, 38.6933 cm2). Wound size measurement using LiDAR is a simple and reliable method that will enable practitioners to conveniently assess wounds with a flattened and irregular shape with higher accuracy. However, non-flattened wounds cannot be assessed owing to the technical limitations of LiDAR. [ABSTRACT FROM AUTHOR]

Introduction: The aim of the study was to evaluate and compare the precision of dimensional measurements in digital panoramic radiographs (PRs) and cone beam computed tomography (CBCT)-generated panoramic images. Materials and Methods: Ten dry human mandibles were subjected to direct anthropometric measurements, digital panoramic radiography, and CBCT scans. Vertical and horizontal measurements were made between predetermined points by two observers. Paired t-test was applied for the comparative analysis. p value

Objective: The study has evaluated the accuracy (trueness and precision) of seven extraoral scan-ners when scanning two different types of jaws: simplified jaw with sharp edges and abutments and realistic jaw with natural teeth. The accuracies of extraoral scanners were compared, and their compliance with the required clinical accuracy levels was discussed.Material and methods: Ten scans were made with each scanner for both models. The comparison of the selected dental scanners relied on reference scans made for both models. Trueness, precision, and the distribution and value of laboratory scan points’ deviations were assessed for each scanner across the models. Results: The trueness for the model of the simplified jaw with abutments ranged from 16.15 to 49.78 μm. The measured precision values for the same model ranged from 4.33 to 29.49 μm. For the model of the realistic jaw with natural teeth, the trueness results ranged from 11.32 to 24.55 μm, while the obtained precision values were between 2.29 and 18.06 μm. Conclusion: The revealed dissimilarities in the accuracies of scanners and their ranking when scanning different models lead to the conclusion that model selection is critical for the research design. All the scanners met the clinical accuracy requirements and are suitable for use in laboratories for scanning jaws with abutments and jaws with natural teeth. However, the accuracy values reported by the manufacturers of scanners are better than those obtained in this study. Furthermore, the results suggested that blue light scanners outperform white light and laser scanners.

Introduction: The aim of the study was to evaluate and compare the precision of dimensional measurements in digital panoramic radiographs (PRs) and cone beam computed tomography (CBCT)- generated panoramic images. Materials and Methods: Ten dry human mandibles were subjected to direct anthropometric measurements, digital panoramic radiography, and CBCT scans. Vertical and horizontal measurements were made between predetermined points by two observers. Paired t-test was applied for the comparative analysis. p value <0.05 was considered statistically significant. Analysis of variance (ANOVA) was done followed by post-hoc Bonferroni test to correlate the measurements got by the three modalities. Results: Except for two vertical measurements (V2 and V4) there was statistically significant difference in relation to all the measurements. The highest mean difference was observed in relation to H4, which was 12.60mm lesser on digital PR in comparison to the anatomic measurements. Also, except for two vertical measurements V1 and V5, all the other measurements were underestimated by the digital PR.Conclusion: Measurement done in reconstructed PR and digital PRs in the region of posterior tooth-bearing region and condylar region are statistically similar. [ABSTRACT FROM AUTHOR]

Background: Three-dimensional (3D) printing is a novel innovation in the field of craniomaxillofacial surgery, however, a lack of evidence exists related to the comparison of the trueness of skull models fabricated using different technology-based printers belonging to different cost segments. Methods: A study was performed to investigate the trueness of cone-beam computed tomography-derived skull models fabricated using different technology based on low-, medium-, and high-cost 3D printers. Following the segmentation of a patient's skull, the model was printed by: (i) a low-cost fused filament fabrication printer; (ii) a medium-cost stereolithography printer; and (iii) a high-cost material jetting printer. The fabricated models were later scanned by industrial computed tomography and superimposed onto the original reference virtual model by applying surface-based registration. A part comparison color-coded analysis was conducted for assessing the difference between the reference and scanned models. A one-way analysis of variance (ANOVA) with Bonferroni correction was applied for statistical analysis. Results: The model printed with the low-cost fused filament fabrication printer showed the highest mean absolute error ( 1.33 ± 0.24 mm ), whereas both medium-cost stereolithography-based and the high-cost material jetting models had an overall similar dimensional error of 0.07 ± 0.03 mm and 0.07 ± 0.01 mm , respectively. Overall, the models printed with medium- and high-cost printers showed a significantly ( p < 0.01 ) lower error compared to the low-cost printer. Conclusions: Both stereolithography and material jetting based printers, belonging to the medium- and high-cost market segment, were able to replicate the skeletal anatomy with optimal trueness, which might be suitable for patient-specific treatment planning tasks in craniomaxillofacial surgery. In contrast, the low-cost fused filament fabrication printer could serve as a cost-effective alternative for anatomical education, and/or patient communication. [ABSTRACT FROM AUTHOR]

Purpose: To compare the accuracy of five different tooth‐implant impression techniques. Materials and Methods: In this in vitro, experimental study, an acrylic model containing one bone‐level Straumann dental implant at the site of maxillary first molar and an adjacent second premolar prepared for a porcelain fused to metal restoration was used. Impressions were made from the model using five different one‐step tooth‐implant impression techniques including scanning with an intraoral scanner, occlusal matrix, wax relief, closed‐tray, and open‐tray techniques. Each technique was repeated 15 times. The impressions were poured with dental stone, and the obtained casts were scanned by a laboratory scanner. The scan file of each technique was compared with the scan file of the original acrylic model by Geomagic Design X software. Data were analyzed by one‐way analysis of variance, and Tamhane's post‐hoc test (α = 0.05). Results: For dental implant, intraoral scanning had the highest accuracy (0.1004 mm2) followed by open‐tray (0.1914 mm2), occlusal matrix (0.2101 mm2), closed‐tray (0.2422 mm2), and wax relief (0.2585 mm2) techniques (p < 0.05). For the prepared tooth, wax relief (0.0988 mm2) had the highest accuracy followed by occlusal matrix (0.1211 mm2), open‐tray (0.1663 mm2), closed‐tray (0.1737 mm2), and intraoral scanning (0.4903 mm2) technique (p < 0.05). For both dental implant and prepared tooth, occlusal matrix (0.2431 mm2) had the highest accuracy followed by open‐tray (0.2574 mm2), wax relief (0.2693 mm2), closed‐tray (0.2862 mm2), and intraoral scanning (0.3192 mm2) technique (p > 0.05). Conclusion: The compared simultaneous tooth‐implant impression techniques had comparable accuracy with no significant difference. [ABSTRACT FROM AUTHOR]

Objectives: The effect of head position on reproducibility of volumetric measurements on Cone‐beam computed tomography (CBCT) scans has not been evaluated before. Thus, this study aimed to assess the changes in linear and volumetric measurements on CBCT scans in different positions of the respective object. Materials and methods: In this experimental study, 16 balls were placed in containers and underwent CBCT in neutral position and 8 different altered positions. The horizontal and vertical diameters of each ball were measured by OnDemand software while the volume of each ball was quantified by ITK‐Snap software. The reproducibility of linear and volumetric measurements in nine different positions was analyzed by the Cronbach's α. Paired t‐test was applied to analyze the difference in volumetric and linear measurements of the balls in the anterior and posterior halves of the scans in neutral position versus the upward and downward tilts, and right and left halves of the scans in neutral position versus the right and left tilts. Results: The Cronbach's α was found to be.982 and.933 for volumetric and linear measurements, respectively, indicating high reproducibility of the measurements. No significant difference was noted in the mean linear measurements on CBCT scans at different positions compared with neutral position. In volumetric measurements, maximum difference between neutral and the other positions was less than 1%. Conclusions: CBCT is a reliable modality for linear and volumetric measurements in different positions. [ABSTRACT FROM AUTHOR]

ABSTRACT Objective: To evaluate the dimensional change of edentulous models made of high density laboratory silicones at different storagetimes. Methods: A metallic master model simulating an edentulous maxilla was used. The model had projections of 1.8 cm located in the regions of canines (A and B) and molars (C and D) allowing the linear measurement of distances AB, BC, CD, DA, AC and BD. A laboratory silicone mold was made for duplication of master model in the following materials (n = 10): G1: Zetalabor 85, G2: Titanium 95, G3: Platinum 95 and G4: Gypsum type III (control). The samples were photographed and measured using a software (Image J) at times T1 (baseline) and T2 (after one week of models fabrication). The data were statistically analyzed using Kruskal- Wallis and Dun non-parametric tests (α = 0.05). Results: The storage time influenced the behavior of the materials evaluated. All groups presented dimensional changes in both times and the group Tit95 presented the best results. Only Zet85 group showed a different behavior related to the region of the model. Conclusions: The high density laboratory silicones showed satisfactory results when compared to the gypsum group. Tit95 was the most stable material and it can be recommended as an edentulous model for total protheses.

The optimal implant position is a critical factor for long-term success in fully edentulous patients. Implants can be placed through conventional freehand, static computer-assisted implant surgery (CAIS), or dynamic CAIS protocols, but at present there is very limited clinical evidence on their accuracy in fully edentulous patients. This study was performed to evaluate the accuracy of implant placement using three protocols in fully edentulous patients. Thirteen patients received 60 implants with the freehand (n = 20), static CAIS (n = 20), or dynamic CAIS (n = 20) protocol. Postoperative cone beam computed tomography was utilized to evaluate the accuracy of implant placement in relation to the planned optimal position. The data were analysed by ANCOVA followed by Bonferroni analysis. The mean angular deviation (standard deviation) in the freehand, static CAIS, and dynamic CAIS groups was 10.09° (4.64°), 4.98° (2.16°), and 5.75° (2.09°), respectively. The mean three-dimensional deviation (standard deviation) at the implant platform in the freehand, static CAIS, and dynamic CAIS groups was 3.48 (2.00) mm, 1.40 (0.72) mm, and 1.73 (0.43) mm, while at the implant apex it was 3.60 (2.11) mm, 1.66 (0.61) mm, and 1.86 (0.82) mm, respectively. No difference in terms of accuracy was found between static and dynamic CAIS; both demonstrated significantly higher accuracy when compared to the freehand protocol in fully edentulous patients. [ABSTRACT FROM AUTHOR]

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Purpose: The purpose of this study was to compare volume measurements obtained using 2 image software packages on Digital Imaging and Communications in Medicine (DICOM) images acquired from 1 multidetector computed tomography and 5 cone-beam computed tomography devices, using different protocols for physical volume measurements. Materials and Methods: Four pieces of bovine leg were prepared. Marrow was removed from 3 pieces, leaving cortical bone exposed. The resulting space of 1 piece was filled with water, another was filled with propylene glycol, and the third was left unfilled. The marrow in the fourth sample was left fully intact. Volume measurements were obtained after importing DICOM images into the Dolphin Imaging 11.95 and ITK-SNAP software programs. Data were analyzed using 3-way analysis of variance with a generalized linear model to determine the effects of voxel size, software, and content on percentage mean volume differences between tomographic protocols. A significance level of 0.05 was used. Results: The intraclass correlation coefficients for intraobserver and interobserver reliability were, respectively, 0.915 and 0.764 for the Dolphin software and 0.894 and 0.766 for the ITK-SNAP software. Three sources of statistically significant variation were identified: the interaction between software and content (P=0.001), the main effect of content (P=0.014), and the main effect of software (P=0.001). Voxel size was not associated with statistically significant differences in volume measurements. Conclusion: Both content and software influenced the accuracy of volume measurements, especially when the content had gray values similar to those of the adjacent tissues. [ABSTRACT FROM AUTHOR]

Objectives: This study evaluated different designs of the conical implant-abutment connection (IAC) and their resistance to microgap formation under oblique loads as specified by the ISO standard for testing dental implants. Also evaluated was the effect of deviations from the ISO specifications on the outcomes., Methods: Finite element analysis was conducted to compare the microgap formation and stress distribution among three conical IAC designs (A, B, and C) in two loading configurations: one compliant with ISO 14801 and one with a modified load adaptor (non-ISO). The different IAC designs varied in the taper, diameter, and cone height. The cone angle mismatch (Cam) between the implant and abutment was considered. A torque of 20 Ncm and oblique loads (up to 400 N) were simulated., Results: The stresses produced by the screw-tightening torque varied among the different IAC designs. The contact height was approximately 0.3 mm for Designs A and B, and less than 0.03 mm for Design C. Under oblique loads, Design A maintained IAC sealing without gap formation up to 400 N. With the ISO adaptor, gaps appeared in Design B at 300 N and in Design C at 90 N. The non-ISO adaptor resulted in gap formation at 160 N for Design B and at 50 N for Design C., Conclusions: The IAC design and cone angle mismatch significantly influenced microgap formation, with some designs showing zero gaps even when the oblique load reached 400 N. The non-ISO adaptor increased gap formation in IACs B and C., (© 2025 Wiley Periodicals LLC.)

Objectives: Evaluating the effect of shape and size of implant scan body on the accuracy of optical 3D scanning., Materials and Methods: Fifteen PEEK scan bodies were milled, including 1 spherical, 9 cylindrical, and 5 cuboidal. The 3D position and angulation of each scan body were measured using a CMM 3 times and a laboratory scanner 10 times. The linear and angular trueness and precision of the scans were calculated by comparing with the CMM measurements., Results: The linear accuracy of the cylindrical scan bodies (9.5 ± 6.2 µm) was significantly higher than those of the cuboidal (17.7 ± 8.1 µm) and spherical scan bodies (12.5 ± 6.5 µm). The cuboidal (0.050±0.009°) showed significantly better angular accuracy than the cylindrical (0.065±0.040°). In the cylindrical group, the narrow (∅4.8 mm) demonstrated significantly inferior accuracy than the wider (∅5.5 mm and ∅6.5 mm)(p = 0.003). The tall (12 mm) showed significantly higher angular trueness than the shorter (8 and 4 mm)(p < 0.001). In the cuboidal group, the 24 mm 2 exhibited significantly poorer angular trueness compared to the 18 mm 2 and 30 mm 2 (p < 0.001) CONCLUSIONS: The shape and size of the implant scan body significantly affect the scanning accuracy. Spherical scan bodies cannot transfer implant angulation. Scan bodies with a size of >∅4.8 mm and >8 mm seem accurate for transferring the 3D implant position., Clinical Significance: The shape and size of scan bodies directly influence the accuracy of 3D scanning. Well-designed scan bodies offer better transfer results, which is crucial for ensuring passive fit of implant prostheses and improving long-term clinical outcomes., 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.)

Aim: Evaluate the accuracy between the intraoral and extraoral scanning regarding the three dimensional (3D) deviation and distances between the implants, through 2 scanning methods. Settings and Design: An in vitro study. Materials and Methods: An edentulous mandibular model was used to install four implants and abutments, recommending 6 distances between the implants. Scans were performed using an intraoral (SI) and extraoral (SE) scanner for each studied group: Scanning with the scan bodies (SB) and device (SD) (n = 10). The files were imported into a surface evaluation program to assess 3D deviations and measure distances between implants. Statistical Analysis: Precision was assessed as the difference between files (Kruskal–Wallis test), while trueness was assessed from the difference between scans, applying the Wilcoxon and Mann–Whitney test. Results: As for the 3D deviations, SI showed accuracy, for the faces and positions of the implants in relation to the SE, in both scanning methods (P < 0.05). Regarding the capture of distances between implants, the SD scan obtained better trueness than the SB group (P < 0.05). Conclusion: We concluded that the type and scanning methods used did not influence the 3D deviations, while for distances, scanning with the device had better trueness.

Simple Summary: This study compared the measured diameters of Response Evaluation Criteria in Solid Tumors (RECIST)-defined chest target lesions and lymph nodes between deep learning image reconstruction (DLIR)-based ultra-low-dose CT (ULDCT) and contrast-enhanced CT and found that the measured diameters in ULDCT were highly correlated with that of contrast-enhanced CT and highly repeatable. It is hopeful to evaluate pulmonary lesions, nodules, and lymph nodes of different sizes by using ULDCT in the future, as it is beneficial to repeated scanning in tumor response evaluation and lung cancer screening. ULDCT is expected to further reduce the radiation dose of chest imaging. Background: Deep learning image reconstruction (DLIR) improves image quality. We aimed to compare the measured diameter of pulmonary lesions and lymph nodes between DLIR-based ultra-low-dose CT (ULDCT) and contrast-enhanced CT. Methods: The consecutive adult patients with noncontrast chest ULDCT (0.07–0.14 mSv) and contrast-enhanced CT (2.38 mSv) were prospectively enrolled. Patients with poor image quality and body mass index ≥ 30 kg/m2 were excluded. The diameter of pulmonary target lesions and lymph nodes defined by Response Evaluation Criteria in Solid Tumors (RECIST) was measured. The measurement variability between ULDCT and enhanced CT was evaluated by Bland-Altman analysis. Results: The 141 enrolled patients (62 ± 12 years) had 89 RECIST-defined measurable pulmonary target lesions (including 30 malignant lesions, mainly adenocarcinomas) and 45 measurable mediastinal lymph nodes (12 malignant). The measurement variation of pulmonary lesions between high-strength DLIR (DLIR-H) images of ULDCT and contrast-enhanced CT was 2.2% (95% CI: 1.7% to 2.6%) and the variation of lymph nodes was 1.4% (1.0% to 1.9%). Conclusions: The measured diameters of pulmonary lesions and lymph nodes in DLIR-H images of ULDCT are highly close to those of contrast-enhanced CT. DLIR-based ULDCT may facilitate evaluating target lesions with greatly reduced radiation exposure in tumor evaluation and lung cancer screening. [ABSTRACT FROM AUTHOR]

PURPOSE. The purpose of this study was to evaluate the influence of different palatal vault configurations on the accuracy and scan speed of intraoral scans (IO) of completely edentulous arches. MATERIALS AND METHODS. Three different virtual models of a completely edentulous maxillary arch with different palatal vault heights- Cl I moderate (U-shaped), Cl II deep (steep) and Cl III shallow (flat)- were digitally designed using CAD software (Meshmixer; Autodesk, USA) and 3D-printed using SLA-based 3D-printer (XFAB; DWS, Italy) (n = 30; 10 specimens per group). Each model was scanned using intraoral scanner (Trios 3; 3Shape™, Denmark). Scanning time was recorded for all samples. Scanning accuracy (trueness and precision) were evaluated using digital subtraction technique using Geomagic Control X v2020 (Geomagic; 3DSystems, USA). One-way analysis of variance (ANOVA) test was used to detect differences in scanning time, trueness and precision among the test groups. Statistical significance was set at α = .05. RESULTS. The scan process could not be completed for Class II group and manufacturer's recommended technique had to be modified. ANOVA revealed no statistically significant difference in trueness and precision values among the test groups ( P=.959 and P=.658, respectively). Deep palatal vault (Cl II) showed significantly longer scan time compared to Cl I and III. CONCLUSION. The selection of scan protocol in complex cases such as deep palatal vault is of utmost importance. The modified, adopted longer path scan protocol of deep vault cases resulted in increased scan time when compared to the other two groups. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the error accumulation and distribution through various stages of the digital workflow for complete‐arch implant‐supported framework fabrication. Materials and methods: A resin model of edentulous maxilla with 6 dental implants was scanned using an intraoral scanner for 10 times (Complete‐digital group). Ten conventional gypsum casts were made and digitized by a laboratory scanner (Analogue‐digital group). Five implant frameworks were designed and milled using CAD‐CAM technique for each workflow. Inter‐implant distances and angles of the resin model (reference) and frameworks were measured by a coordinate measuring machine, while the scans and virtual frameworks were examined by an inspection software. Effect of type of workflow and the individual stage on the accuracy of the frameworks were analysed by Two‐way ANOVA. Results: The expanded uncertainty of both workflows was ~150 μm and ~ 0.8°. The accuracy of the CAD stage was the highest. In the complete‐digital workflow, the greatest distortion was found in the data acquisition stage, while in the analogue‐digital workflow, it was found in the CAM stage. Compared with the analogue‐digital group, the complete‐digital group showed a significant higher precision in the first quadrant, but lower trueness in the second quadrant in data acquisition, and a significantly lower precision in the second quadrant at the CAD stage. Conclusions: Linear distortions of the complete‐digital and analogue‐digital workflows were clinically acceptable, while angular distortions were not. Distortions were generally derived from data acquisition and CAM stage. The CAD precision depended on the distortions derived from data acquisition. The complete‐digital workflow was not as accurate as the analogue‐digital in complete‐arch implant rehabilitation. [ABSTRACT FROM AUTHOR]

BACKGROUND: Computer-aided design and three-dimensional printing have been used in various clinical and fundamental medicine fields, especially in surgery. For example, in the preoperative period, the correspondence of printed products to the anatomy can play an important role in evaluating pathological changes and correction methods. However, determining dimensional deviations of printed models involves ethical and technical difficulties associated with defining a reference and taking many measurements, respectively. Therefore, we propose to use a geometric object with known dimensions as a reference and estimate linear deviations using the Iterative Closest Point algorithm for each of the vertices of the prototyped polygonal mesh. AIMS: To evaluate the geometric deviations associated with creation of bone-like physical objects from computed tomography data using computer-aided design and additive manufacturing. MATERIALS AND METHODS: The source object was created using the FreeCAD application; Blender and Meshmixer software was used for polygon meshes correction and transformation. The 3D printing was carried out on an Ender-3 printer with copper-impregnated polylactide plastic BFCopper. Scanning was performed using a 128-slice tomograph Philips Ingenuity CT. A series of tomographic images were processed in 3DSlicer software to create virtual models by semiautomatic segmentation with threshold values of 500 HU, 0 HU, 500 HU, 750 HU, and manual segmentation. Reproduced and reference polygon meshes were compared using the Iterative Closest Point algorithm in CloudCompare software. RESULTS: The volume of reproduced models exceeded the volume of respective reference models by 1%27%. The average point cloud linear deviation values of reproduced models from the reference ones were 0.030.41 mm. A significant correlation between integral sums of linear deviations and changes in the volume of reproduced models was shown using Spearman's rank correlation coefficient ( = 0.83; temp = 5.27, p=0.05). CONCLUSION: The geometry of the reproduced object changes inevitably, while the linear deviations depend more on the chosen segmentation method than on the overall size of the model or its structures. The manual segmentation method can lead to greater linear deviations, though it saves all the necessary anatomical structures.

Purpose: To measure and compare the accuracy of the linear dimensions of implant sites recorded from cone beam computed tomography (CBCT) images using Blue Sky Plan, coDiagnostiX, and RadiAnt. Materials and Methods: Five human dry skulls were imaged with a CBCT device then sectioned to obtain sample transverse cross-sections of the edentulous ridges, and the height and width of the ridge were measured with a digital caliper to provide the gold standard measurements. The CBCT datasets were exported in DICOM format and imported into the three test software programs which were used to obtain reformatted sectional images corresponding to the sample transverse cross-sections, and the height and width of the edentulous ridge was recorded using the linear measurement tool. Reliability of the measurements were measured using the intraclass correlation coefficient. One-sample t-test (test value: zero) was used to test the statistical significance of the mean of the absolute errors for each software program. Analysis of Variance with Repeated Measures was used to test the statistical significance of the difference between the means of the absolute errors obtained by the different software programs. Statistical significance was set at a p-value of 0.05. Results: The reliability of the gold standard and image measurements were excellent. All three software programs demonstrated a statistically significant mean absolute measurement error of between 0.43 and 0.56 mm (p-value

Abstract Background Material extrusion is used to 3D print anatomic models and guides. Sterilization is required if a 3D printed part touches the patient during an intervention. Vaporized Hydrogen Peroxide (VHP) is one method of sterilization. There are four factors to consider when sterilizing an anatomic model or guide: sterility, biocompatibility, mechanical properties, and geometric fidelity. This project focuses on geometric fidelity for material extrusion of one polymer acrylonitrile butadiene styrene (ABS) using VHP. Methods De-identified computed tomography (CT) image data from 16 patients was segmented using Mimics Innovation Suite (Materialise NV, Leuven, Belgium). Eight patients had maxillary and mandibular defects depicted with the anatomic models, and eight had mandibular defects for the anatomic guides. Anatomic models and guides designed from the surfaces of CT scan reconstruction and segementation were 3D printed in medical-grade acrylonitrile butadiene styrene (ABS) material extrusion. The 16 parts underwent low-temperature sterilization with VHP. The dimensional error was estimated after sterilization by comparing scanned images of the 3D printed parts. Results The average of the estimated mean differences between the printed pieces before and after sterilization were − 0,011 ± 0,252 mm (95%CI − 0,011; − 0,010) for the models and 0,003 ± 0,057 mm (95%CI 0,002; 0,003) for the guides. Regarding the dimensional error of the sterilized parts compared to the original design, the estimated mean differences were − 0,082 ± 0,626 mm (95%CI − 0,083; − 0,081) for the models and 0,126 ± 0,205 mm (95%CI 0,126, 0,127) for the guides. Conclusion This project tested and verified dimensional stability, one of the four prerequisites for introducing vaporized hydrogen peroxide into 3D printing of anatomic models and guides; the 3D printed parts maintained dimensional stability after sterilization.

Purpose: To assess the three-dimensional (3D) accuracy and clinical acceptability of implant definitive casts fabricated using a digital impression approach and to compare the results with those of a conventional impression method in a partially edentulous condition. Materials and Methods: A mandibular reference model was fabricated with implants in the first premolar and molar positions to simulate a patient with bilateral posterior edentulism. Ten implant-level impressions per method were made using either an intraoral scanner with scanning abutments for the digital approach or an open-tray technique and polyvinylsiloxane material for the conventional approach. 3D analysis and comparison of implant location on resultant definitive casts were performed using laser scanner and quality control software. The inter-implant distances and interimplant angulations for each implant pair were measured for the reference model and for each definitive cast (n = 20 per group); these measurements were compared to calculate the magnitude of error in 3D for each definitive cast. The influence of implant angulation on definitive cast accuracy was evaluated for both digital and conventional approaches. Statistical analysis was performed using t test (α = .05) for implant position and angulation. Clinical qualitative assessment of accuracy was done via the assessment of the passivity of a master verification stent for each implant pair, and significance was analyzed using chi-square test (α = .05). Results: A 3D error of implant positioning was observed for the two impression techniques vs the reference model, with mean ± standard deviation (SD) error of 116 ± 94 μm and 56 ± 29 μm for the digital and conventional approaches, respectively (P = .01). In contrast, the inter-implant angulation errors were not significantly different between the two techniques (P = .83). Implant angulation did not have a significant influence on definitive cast accuracy within either technique (P = .64). The verification stent demonstrated acceptable passive fit for 11 out of 20 casts and 18 out of 20 casts for the digital and conventional methods, respectively (P = .01). Conclusion: Definitive casts fabricated using the digital impression approach were less accurate than those fabricated from the conventional impression approach for this simulated clinical scenario. A significant number of definitive casts generated by the digital technique did not meet clinically acceptable accuracy for the fabrication of a multiple implant-supported restoration. [ABSTRACT FROM AUTHOR]

The aim was to evaluate the accuracy of a prototypical artificial intelligence-based algorithm for automated segmentation and diameter measurement of the thoracic aorta (TA) using CT. One hundred twenty-two patients who underwent dual-source CT were retrospectively included. Ninety-three of these patients had been administered intravenous iodinated contrast. Images were evaluated using the prototypical algorithm, which segments the TA and determines the corresponding diameters at predefined anatomical locations based on the American Heart Association guidelines. The reference standard was established by two radiologists individually in a blinded, randomized fashion. Equivalency was tested and inter-reader agreement was assessed using intra-class correlation (ICC). In total, 99.2% of the parameters measured by the prototype were assessable. In nine patients, the prototype failed to determine one diameter along the vessel. Measurements along the TA did not differ between the algorithm and readers (p > 0.05), establishing equivalence. Inter-reader agreement between the algorithm and readers (ICC ≥ 0.961; 95% CI: 0.940–0.974), and between the readers was excellent (ICC ≥ 0.879; 95% CI: 0.818–0.92). The evaluated prototypical AI-based algorithm accurately measured TA diameters at each region of interest independent of the use of either contrast utilization or pathology. This indicates that the prototypical algorithm has substantial potential as a valuable tool in the rapid clinical evaluation of aortic pathology. [ABSTRACT FROM AUTHOR]