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Purpose: The objective of this retrospective study was to evaluate the effect of the interproximal contour of single external hexagon implant restorations on the prevalence of peri‐implantitis. Material and Methods: Records of 96 patients and 148 external hexagon (EH) implants with time in function ranging from 1 to 17 years were included in the study. The most recent clinical and radiographic data were collected from records and the prevalence of peri‐implantitis was defined according to the 2017 World Workshop on the Classification of Periodontal and Peri‐implant Diseases and Conditions. Marginal bone level (MBL), emergence angle (EA), emergence profile (EP), and crown/implant platform horizontal ratio (CIHR) were obtained from periapical radiographs. Dichotomous variables at the patient‐ and implant level were compared with association tests. Mann‐Whitney U‐Test was performed to compare continuous quantitative values between the studied groups. Binomial logistic regression was conducted to identify risk indicators associated with the peri‐implantitis event at the patient‐ and implant level, with the significance level set at 5% for all tests. Results: Nineteen patients (19.2%) and 24 implants (16.2%) with a mean time in function of 5.0 ± 4.7 years were classified as having peri‐implantitis. No statistically significant differences concerning gender, mean age, implant location in the jaw, or time in function were observed between patients with or without peri‐implantitis (p > 0.05). Of 24 implants with peri‐implantitis 10 (41.7%) displayed EA ≤ 30° (16.4%) while 14 (58.3%) presented EA > 30° with no statistical difference between the groups (p > 0.05). No statistically significant associations were identified between EA, EP, or CIHR and the prevalence of peri‐implantitis. Conclusion: The findings seem to indicate that the EA, EP, and CIHR of single restorations over external hexagon implants are not associated with the presence of peri‐implantitis. However, prospective studies with larger samples are required to better ascertain such an association in the long term. [ABSTRACT FROM AUTHOR]

Purpose: This review aimed to summarize the evidence on patient‐reported outcomes and clinical performance of digitally fabricated removable partial dentures (RPDs) compared to traditionally fabricated dentures. Methods: Three databases were systematically searched (PubMed, CENTRAL, and Wiley online library) for clinical studies comparing digitally and conventionally fabricated RPDs regardless of data acquisition methods used for fabrication. The Cochrane Collaboration risk of bias assessment tool 2 and the Oxford Center for Evidence‐based Medicine tool were used to assess risk of bias, and level of evidence, respectively. Descriptive narrative analysis was used to summarize data on patient‐reported outcomes, as there were inadequate studies to pool data in a meta‐analysis. A random‐effects model was used to analyze the data of framework fit accuracy. Results: Ten randomized controlled trials were included in the systematic review, and 4 were included in the meta‐analysis. Two studies showed that digitally fabricated RPDs are associated with higher patient satisfaction than conventionally fabricated RPDs (with a mean difference of 12.5 mm on a 100‐satisfaction scale, p =.008). The pooled standardized mean difference for framework fit accuracy was 0.49 (p = 0.02) in favor of conventionally fabricated RPDs, which showed that conventionally fabricated RPDs have a quantitatively better fit compared to digitally fabricated RPDs. However, clinical evaluation studies showed that both frameworks have clinically acceptable fit. Conclusions: Current evidence shows that digitally fabricated RPDs are associated with higher patient satisfaction compared to conventionally fabricated RPDs. However, the scarcity of literature here warrants the generalization of this conclusion. Both digitally and conventionally fabricated metal RPD frameworks showed acceptable fit clinically. [ABSTRACT FROM AUTHOR]

When fabricating a maxillary full‐arch implant‐supported fixed dental prosthesis, it is often challenging to systematically reduce alveolar bone to create prosthetic space and hide the prosthesis‐tissue junction. This article presents a digital technique that allows for precise bone reduction while simultaneously placing implants and interim prostheses. By using this technique, clinicians can perform surgical procedures in a systematic manner without compromising the functional or esthetic outcomes. [ABSTRACT FROM AUTHOR]

Purpose: To compare the impact of three different chemical denture cleansers (CDCs) (Corega, chlorhexidine, and hydrogen peroxide) on the surface roughness, microhardness, and color stability of 3D‐printed, computer‐aided design and computer‐aided manufacturing (CAD‐CAM) milled, and heat‐polymerized denture base material (DBM). Materials and Methods: A total of 420 disc‐shaped specimens (10 ± 0.1 × 2 ±0.1 mm) were fabricated using three different construction techniques: three‐dimensional (3D) printing (n = 140), CAD‐CAM milling (n = 140), and heat‐polymerization (n = 140). Sixty specimens (20 of each DBM) were used for baseline (pre‐immersion) measurements (T1) for the tested surface properties (hardness [n = 10/material] and roughness [n = 10/material]). The remaining 360 specimens (n = 120/material) were investigated for surface roughness, microhardness, and color change after immersion for 1 year (T2) in distilled water or CDCs (n = 30/solution and n = 10/test). The data were analyzed using two‐way ANOVA, one‐way ANOVA followed by post‐hoc Tukey's test at a significance level of less than 0.05. Results: Significant differences were observed in the effects of the tested CDCs on the surface roughness, micro‐hardness, and color stability of varying DBM specimens (p < 0.05). Corega showed the highest surface roughness and color change in all DBMs while H2O2 resulted in the lowest microhardness for all DBMs. The lowest changes in all tested properties were seen with distilled water followed by chlorhexidine. A significant effect of type of cleanser, denture base material, and the interaction between the two was seen on all measured properties (p < 0.05). Conclusions: The tested CDCs significantly affected the surface properties of all DBMs but at varying degrees. Corega produced the highest negative effect on roughness and color change while H2O2 dramatically affected the microhardness. Prolonged use of CDCs should be cautiously followed. [ABSTRACT FROM AUTHOR]

Purpose: Uses for artificial intelligence (AI) are being explored in contemporary dentistry, but artificial intelligence in dental shade‐matching has not been systematically reviewed and evaluated. The purpose of this systematic review was to evaluate the accuracy of artificial intelligence in predicting dental shades in restorative dentistry. Methods: A systematic electronic search was performed with the databases MEDLINE (PubMed), Scopus, Cochrane Library, and Google Scholar. A manual search was also conducted. All titles and abstracts were subject to the inclusion criteria of observational, interventional studies, and studies published in the English language. Narrative reviews, systematic reviews, case reports, case series, letters to the editor, commentaries, studies that were not AI‐based, studies that were not related to dentistry, and studies that were related to other disciplines in dentistry, other than restorative dentistry (prosthodontics and endodontics) were excluded. Two investigators independently evaluated the quality assessment of the studies by applying the Joanna Briggs Institute Critical Appraisal Checklist for Quasi‐Experimental Studies (non‐randomized experimental studies). A third investigator was consulted to resolve the lack of consensus. Results: Fifty‐three articles were initially found from all the searches combined from articles published from 2008 till March 2023. A total of 15 articles met the inclusion criteria and were included in the systematic review. AI algorithms for shade‐matching include fuzzy logic, a genetic algorithm with back‐propagation neural network, back‐propagation neural networks, convolutional neural networks, artificial neural networks, support vector machine algorithms, K‐nearest neighbor with decision tree and random forest, deep learning for detection of dental prostheses based on object‐detection applications, You Only Look Once‐YOLO. Moment invariant was used for feature extraction. XG (Xtreme Gradient) Boost was used in one study as a gradient‐boosting machine learning algorithm. The highest accuracy in the prediction of dental shades was the decision tree regression model for leucite‐based dental ceramics of 99.7% followed by the fuzzy decision of 99.62%, and support vector machine using cross‐validation of 97%. Conclusions: Lighting conditions, shade‐matching devices and color space models, and the type of AI algorithm influence the accuracy of the prediction of dental shades. Knowledge‐based systems and neural networks have shown better accuracy in predicting dental shades. [ABSTRACT FROM AUTHOR]

Purpose: This systematic review and meta‐analysis aimed to investigate the prevalence of opportunistic respiratory pathogens colonizing removable dental prostheses in older adults without respiratory diseases. Methods: This review was registered with PROSPERO and conducted in accordance with the principles formed by the working group of the Joanna Briggs Institute (JBI) to evaluate systematic reviews of prevalence data. Literature searches were conducted across five electronic databases. Quality assessments were determined according to a revised JBI critical appraisal checklist across nine criteria. Comparison between fixed‐ and random‐effects meta‐analyses were performed for sensitivity analysis. Prediction intervals were also presented when three or more studies were included in the meta‐analysis. Results: Across the databases, 1091 articles were identified, and 591 articles remained after the removal of duplicates. Twenty "potentially effective" studies were identified. Ultimately eight studies informed this review and meta‐analyses were performed for 13 known respiratory pathogens. The meta‐analyses identified the top three common respiratory pathogens residing on the removable prostheses were, in descending order: Staphylococcus aureus: 31.81% (95% CI: 13.34%–48.24%); Staphylococcus epidermidis: 14.07% (95% CI: 7.88%–21.48%); Klebsiella pneumoniae: 10.50% (95% CI: 2.55%–22.30%). The heterogeneity scores for nine respiratory pathogen analyses were classified as "unimportant inconsistency", I2 = 0% (p > 0.1). For sensitivity analysis, there was no difference between the random‐ and fixed‐effects models. Conclusion: The existing evidence demonstrated a high burden of certain opportunistic respiratory pathogens, which may be considered a major potential cause of respiratory infections in older adults wearing removable prostheses. [ABSTRACT FROM AUTHOR]

Purpose: Older adults with removable dentures experience high rates of both caries (when the natural dentition remains) and salivary gland dysfunction. While many commercial dental therapeutic agents target these two interrelated problems, none have been labeled for use on the fitting surface of removable dentures. Off‐label use of MI Paste (GC America, Alsip, IL), a dental therapeutic containing casein‐phosphopeptide‐amorphous‐calcium‐phosphate (CPP‐ACP), was investigated following its application to the fitting surface of complete denture(s) with subsequent effects on salivary conditions measured. Materials and methods: Salivary flow rate and pH were recorded at baseline and 15 min following the application of 1 mL of CPP‐ACP paste to the fitting surface of each participant's denture through whole saliva collection. To assess buffering capacity, equivalent volumes of 0.01 M lactic acid were added to the collected saliva samples, and pH reduction was measured. Comparisons of salivary parameters between baseline and post‐CPP‐ACP paste application and between subjects with and without self‐reported xerostomia were conducted using a paired‐sample t‐test, Wilcoxon signed‐rank test, or two‐sample t‐test as appropriate. Results: Of the 28 participants (mean age = 70.3 ± 13.7 years, 17 males), 11 reported xerostomia. CPP‐ACP‐paste application was associated with decreased pH reduction during acid challenge compared to baseline (0.95 ± 0.24 vs. 1.54 ± 0.53, p < 0.001), and a higher final pH following acid challenge (5.93 ± 0.34 vs. 5.40 ± 0.66, p < 0.001). While the flow rates observed at post‐CPP‐ACP paste application were greater than those at baseline, the difference was not statistically significant (0.67 ± 0.44 mL/min vs. 0.55 ± 0.34 mL/min, p = 0.053). No significant differences were found in any salivary parameters between participants with or without self‐reports of xerostomia. Conclusions: The findings highlight potential positive effects on salivary conditions following the application of the CPP‐ACP‐containing product, MI Paste, to the fitting surface of a removable complete denture as a potential caries‐risk‐management tool when natural dentition remains. Determining the caries‐preventive clinical significance will require longer‐term trials. [ABSTRACT FROM AUTHOR]

This article presents a technique for fabricating two‐piece labial guides using resin and cobalt‐chromium for guided alveoloplasty, implant placement, and immediate full‐arch implant‐supported fixed complete denture placement. This technique reduces tissue damage and overcomes the negative effect of the anatomical position of the palatal neuropore and mobility of the tissue flap on the positioning and stability of the guide. The use of labial retention metal guides with improved mechanical properties of cobalt‐chromium and fixation plugs allows the unilateral placement of the guide. Thus, minimally invasive implant surgery can be performed owing to the absence of large palatal flap elevation and obstruction. Such a design provides better stability of the guides and clear visual access during surgery. [ABSTRACT FROM AUTHOR]

Purpose: Denture Stomatitis, a chronic mucosal inflammation associated with Candida albicans, is common among denture wearers. Several health conditions have been linked to chronic Candida infections. The complex, multifactorial nature of denture stomatitis requires the continuous pursuit of effective long‐term solutions. The present in vitro study investigated the effect of incorporating organoselenium into 3D‐printed denture base resin on C. albicans adhesion and biofilm formation. Materials and Methods: Thirty disks were fabricated using 3D‐printed denture base resin and assigned to three experimental groups (10/group): disks without organoselenium (control), disks with 0.5% organoselenium (0.5%SE), and disks with 1% organoselenium (1%SE). Each disk was incubated with approximately 1 × 106 cells/mL of C. albicans for 48 h. Microbial viability (CFU/mL) was quantified by the spread plate method, while Confocal laser scanning microscopy and scanning electron microscope were performed for quantifying the biofilm thickness and examining biofilm morphology, respectively. Data were analyzed using One‐way ANOVA with Tukey's multiple comparisons test. Results: CFU/mL was significantly (p < 0.05) higher in Control when compared with 0.5%SE and 1%SE, but no significant difference between 0.5%SE and 1%SE. A similar trend was observed with biofilm thickness except that there was no significant difference between the Control and 0.5%SE. There was C. albicans biofilm adhesion on the Control disks, with yeast cells and hyphae formation, whereas on 0.5%SE and 1%SE, there was inhibition of yeast cells transition to hyphae formation. Conclusions: Incorporation of organoselenium into 3D‐printed denture base resin was effective in reducing C. albicans biofilm formation and growth on denture base material. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate and compare the initial retention force of three resilient unsplinted attachment systems for implant‐retained mandibular overdentures: two cylindrical attachment systems (Locator R‐Tx® and Novaloc®), and one ball attachment system (Ball System). Materials and Methods: For each attachment system, initial retention is measured as the average of the maximal dislodging forces during 10 insertion‐removal cycles. For the Ball System, three activation degrees of the matrix are included versus four and six color‐coded retention devices for the Locator R‐Tx® and the Novaloc®, respectively, to represent the complete regular retention devices panel. For each retention device or activation degree, eight samples are tested. Results: The initial retention range is similar between the Ball System (7.7 ± 3.4 N – 19.9 ± 4.6 N) and the Novaloc® (2.0 ± 0.5 N – 18.9 ± 1.4 N) and broader for the Locator R‐Tx® (3.3 ± 5.0 N – 60.2 ± 6.0 N). In each attachment system, the initial retention of each retention device is significantly different from the others, except for the two most retentive Novaloc® ones. Retention devices were also classified according to their initial retention (low, medium, and maximum). In each retention group, the Novaloc® and the Ball System provided similar retention values lower than the Locator R‐Tx®. Conclusion: Most of the retention devices tested provided an initial retention force of over 5 N for all three attachment systems. The Locator R‐Tx® had the most comprehensive range, and the Novaloc® seemed to provide the most reproducible values, unlike the Ball System due to the activation required by the operator. [ABSTRACT FROM AUTHOR]

Microstomia presents a challenge for the patient and dental provider. This report describes a partial digital workflow for the fabrication of a mandibular complete denture for a patient with microstomia. Computer‐aided design and computer‐aided manufacturing technology was utilized to 3D print a sectional custom tray with a unique design. The sectional custom tray was used to make a conventional border molded impression of the edentulous arch to fabricate a flexible complete mandibular denture for a 58‐year‐old female patient with scleroderma and microstomia. This treatment resulted in a successful prosthetic outcome and high patient satisfaction. [ABSTRACT FROM AUTHOR]

Purpose: Single implant retained mandibular overdenture treatment has been shown to be a minimally invasive, satisfactory, and cost‐effective option for edentulous individuals. However, the impact of implant diameter and length on stress distribution at the implant, bone, and other components in this treatment approach remains unclear. The purpose of this 3D finite element analysis was to evaluate the effect of implant length and diameter on equivalent von Mises stress and strain distribution in single implant retained overdentures at bone, implant, and prosthetic components. Materials and Methods: Nine models were constructed according to implant lengths (L) (8, 10, 12 mm) and diameters (D) (3.3, 4.1, 4.8 mm). The implants were positioned axially, in the midline of the mandible. A 3D model of the edentulous mandible was created from a computed tomography image. A single implant, abutment with insert PEEK and a housing, acrylic denture, and Co‐Cr framework were modeled separately. In the ANSYS software program, occlusal loads were applied as 150 N, bilaterally vertical direction, or unilaterally oblique direction to the first molar. Minimum principal stress values were evaluated for bone and equivalent von Mises stress and strain values were evaluated for implant and prosthetic components. Results: Von Mises stress values for vertical load increased at implant, housing, and insert PEEK for all groups when the length of the implant increased. When oblique load was applied, 3.3 mm diameter implant groups showed maximum von Mises stress values for implants, cortical bone, cancellous bone, and housing among all groups. A minimum stress level for implant was found in D4.1/L8 group. Regarding the insert PEEK, strain values were found to be higher as the diameter of the implant increased both for vertical and oblique loads. Cortical bone showed higher minimum principal stress values as compared to cancellous bone under both loading conditions. Conclusions: The 3.3 mm diameter implant groups exhibited the highest von Mises stress and strain values for both loading conditions at the implant. The diameter of the implant had a greater impact on stress and strain levels at the implant site compared to length. For vertical loading, stress value increased at implant, housing, and PEEK when the length of the implant increased. [ABSTRACT FROM AUTHOR]

Digital replication of an existing cast gold onlay anatomy to a more esthetic material for a new complete denture is challenging. A technique is presented that uses digital technology to fabricate a new maxillary complete denture with monolithic zirconia onlays that duplicate the anatomy of an existing complete denture with cast gold onlays. [ABSTRACT FROM AUTHOR]

Purpose: To compare the effects of two denture adhesive formulations on the bite force required to dislodge a maxillary denture in adult participants during a 13‐h test period. Materials and Methods: Twenty‐two participants with a fair‐to‐poor fitting maxillary denture opposed by natural dentition or a stable mandibular denture were enrolled in this single‐center, randomized, double‐blind, two‐treatment, 4‐period crossover study. Participants were randomly assigned a product usage sequence so that each participant used each product twice during the 4‐day test period. The test product was a denture cream adhesive formulated with an optimized calcium/zinc partial salt of polyvinyl methyl ether/maleic acid (Fixodent Ultra technology); the control product was a cream adhesive formulated with a calcium/zinc partial salt of polyvinyl methyl ether/maleic acid (Fixodent Original technology). On each study day, bite force at dislodgement was measured with a gnathodynamometer at baseline, representing the "no adhesive" score. Then, after standardized product application to the participant's existing maxillary denture by site staff, bite force measurements were retaken at 1, 3, 5, 7, 9, 11, and 13 h. The change from baseline and the 13‐h area under the bite‐force–change‐from‐baseline curve were analyzed via an analysis of variance. Results: Twenty‐one participants completed all test periods; one additional participant completed three test periods so 22 participants were included in the analysis. There were 15 females and 7 males with a mean age of 70 years. The mean 13‐h area under the bite‐force–change‐from‐baseline curve was 8% greater (p = 0.010) for the test adhesive (114.3 lb) than for the control adhesive (105.9 lb). Both adhesives showed a statistically significant increase in bite force (p < 0.001) at each time point compared to no adhesive. Conclusions: The optimized calcium/zinc partial salt of polyvinyl methyl ether/maleic acid test adhesive provided superior maxillary denture retention relative to that of the control adhesive across 13 h. Both adhesives increased bite force at dislodgement compared to no adhesive. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this in vitro study was to assess the color match of ultra‐translucency multilayer zirconia restorations with different designs and backgrounds. Materials and methods: Thirty ultra‐translucency multilayer zirconia crown specimens were made in VITA classical shade B2 for a prepared maxillary central incisor. The specimens were divided into three groups based on the restoration design: veneered zirconia with a trestle design (VZT), veneered zirconia with a dentin core design (VZD), and full‐contour zirconia (FCZ). In the groups VZT and VZD, the zirconia specimens were layered with a feldspathic veneering ceramic. The specimens were seated on five different backgrounds: shade B2 composite resin, shade B2 zirconia, copper‐colored metal alloy, silver‐colored metal alloy, and the prepared central incisor. CIELab values of the labial middle sections of the crown specimens were measured with a spectrophotometer. Color differences between the specimens and a shade B2 VITA classical tab (as a control) were calculated from the ΔE*ab formula and compared with an acceptability threshold (ΔE*ab = 3.7) to be clinically explicated. Results: Mean ΔE*ab values ranged between 1.17 and 8.48. The restoration design, the background type, and their interaction affected the ΔE*ab (p < 0.001). The mean ΔE*ab values for VZT with all backgrounds and for VZD with the silver‐colored metal background were greater than the threshold (p < 0.001), whereas the mean ΔE*ab values for VZD with the other backgrounds and FCZ with all backgrounds were less than the threshold (p = 1). Conclusions: Restoration design and background type affected the color match of ultra‐translucency multilayer zirconia restorations. VZT restorations on all backgrounds and VZD restorations on a silver‐colored metal background showed color mismatches. However, VZD restorations on the other backgrounds and FCZ restorations on all backgrounds demonstrated color matches. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this in vitro study was to assess the effects of using different cements and titanium copings designs on the retention of implant‐supported fixed dental prostheses (IFDPs) using a pull‐out test. Materials and Methods: Fifty zirconia (ZirCAD; Ivoclar Vivadent) and 20 prepolymerized denture acrylic resin (AvaDent) rectangular (36 mm × 12 mm × 8 mm) specimens were milled to mimic the lower left segmental portion of the All‐on‐Four IFDPs. Cylindrical titanium copings (Variobase; Straumann) (V) were used in 2 prepolymerized denture acrylic resin groups (n = 10) while conical titanium copings (Straumann) (C) were used as a control group for zirconia with 4 groups using cylindrical titanium copings. Before cementation, the outer surfaces of all titanium copings and the intaglio bonding surface of prosthetic specimens were airborne‐particle abraded. All specimens were cemented following the manufacturer's recommendations and instructions according to the experimental design. After artificial aging (5000 cycles of 5°C 55°C, dwelling time 20 s; 150 N, 1.5 Hz in a 37°C water bath), all specimens were subjected to retention force testing using a pull‐out test using a universal testing machine and a custom fixture with a crosshead speed 5 mm/min. Modes of failure were classified as Type 1, 2, or 3. Retention force values were analyzed by the t‐test for the prepolymerized denture acrylic resin specimen groups, and 1‐way ANOVA and the Tukey test for the zirconia groups at α = 0.05. Results: Mean and standard deviation retention force values varied from 101.1 ± 67.1 to 509.0 ± 65.2 N for the prepolymerized denture acrylic resin specimen groups. The zirconia groups ranged from 572.8 ± 274.7 to 1416.1 ± 258.0 N. There is no statistically significant difference in retention force values between V and C specimens cementing to zirconia with Panavia SA cement (Kuraray Noritake) (p = 0.587). The retention forces and failure modes were influenced by the cement used (p < 0.05). Modes of failure were predominantly Type 2 (mixed failure) and Type 1 (adhesive fracture from prosthetic materials) except for the quick‐set resin group (Type 3, adhesive failure from coping). Conclusions: When bonding IFDPs onto titanium copings, quick‐set resin provided significantly higher retention force for prepolymerized denture acrylic resin prostheses. Conical and cylindrical titanium copings performed similarly when cemented to zirconia with Panavia SA cement under the same protocol. The stability of the bonded interface and retention forces between zirconia prostheses and titanium copings varied from the cement used. [ABSTRACT FROM AUTHOR]

Purpose: To assess the clinical performance of screw‐retained, ceramic‐veneered, monolithic zirconia partial implant‐supported fixed dental prostheses (ISFDP) over 5–10 years and to evaluate implant‐ and prosthesis‐related factors influencing treatment failure and complications. Materials and methods: Partially edentulous patients treated with screw‐retained all‐ceramic ISFDPs with 2–4 prosthetic units with a documented follow‐up of ≥5 years after implant loading were included in this retrospective study. The outcomes analyzed included implant/prosthesis failure and biological/technical complications. Possible risk factors were identified using the mixed effects Cox regression analysis. Results: A screened sample of 171 participants with 208 prostheses (95% of the restorations were splinted crowns without a pontic) supported by 451 dental implants were enrolled in this study. The mean follow‐up duration after prosthesis delivery was 82.4 ±17.2 months. By the end of the follow‐up period, 431 (95.57%) of the 451 implants remained functional at the implant level. At the prosthesis level, 185 (88.94%) of the 208 partial ISFDPs remained functional. Biological complications were observed in 67 implants (14.86%), and technical complications were observed in 62 ISFDPs (29.81%). Analysis revealed only emergence profiles (over‐contoured) as a significant risk factor for implant failure (P<0.001) and biological complications (P<0.001). Full‐coverage ceramic‐veneered zirconia prostheses had a significantly greater chance of chipping (P<0.001) compared with buccal‐ceramic‐veneered or monolithic zirconia prostheses. Conclusions: Screw‐retained ceramic‐veneered, monolithic partial ISFDPs have a favorable long‐term survival rate. Over‐contoured emergence profile is a significant risk factor associated with implant failure and biological complications. Buccal‐ceramic‐veneered and monolithic zirconia partial ISFDPs lower the initial prevalence of chipping compared with a full‐coverage veneered design. [ABSTRACT FROM AUTHOR]

This article presents the design of customized resin scan bodies with different forms and their use to facilitate intraoral scanning of a maxillary full arch implant case with five implants. The aim is to limit the distance between the scan bodies and to create definite landmarks to facilitate the scanning process in full arch implant cases. [ABSTRACT FROM AUTHOR]

Purpose: The aim was to assess the effect of span lengths and total occlusal convergence (TOC) on the accuracy of intraoral scanners. Materials and methods: Two typodont acrylic teeth models were prepared to receive fixed dental prostheses with three different span lengths. Span 1: between maxillary canines; span 2: between maxillary second premolars; and span 3: between maxillary second molars. In the first model, prepared teeth had a TOC of 12°, whereas, in the second model, teeth had a TOC of 20°. Each model was scanned 10 times using 4 different intraoral scanners (Omnicam, Primescan, Trios 4, and Medit i500). The STL files from the scans were compared to the reference models (trueness) and within each test group (precision) using a 3D comparison software. Data were then statistically analyzed. Results: Regarding trueness, no significant differences were found among Primescan (32.58 ± 13.08), Trios 4 (32.33 ± 12.19), and Medit i500 (32.26 ± 9.57). However, all showed significantly better trueness than Omnicam (35.70 ± 8.35) (p < 0.001). The highest values were found in scans between the second molars (47.42 ± 3.94), followed by scans between second premolars (28.42 ± 3.78), and the highest trueness was found in scans between the canines (23.80 ± 3.85). For TOC, 12° had a significantly higher value than 20° (p < 0.001). Regarding precision, the highest values were found with Omnicam (29.84 ± 3.89), followed by Medit i500 (28.04 ± 2.94), then Trios 4 (25.64 ± 3.11), and Primescan (24.69 ± 5.25). The highest values and least precision were found in scans between the second molars (28.97 ± 5.27) and scans between second premolars (27.59 ± 3.97), whereas the highest precision was found in scans between the canines (24.60 ± 2.04). For TOC, 12° had significantly higher values than 20° (p < 0.001). Conclusions: Intraoral scans are directly affected by scanner type, TOC, and scan spans. All tested scanners showed clinically acceptable results even for long‐span restorations. [ABSTRACT FROM AUTHOR]

Purpose: There are different methods to transfer occlusal vertical dimension (OVD) when fabricating complete dentures, but it is not clear which method yields the most accurate transfer. This study investigated the accuracy of transferring the OVD of the maxillary/mandibular relationship when designing and fabricating digital dentures by evaluating two commonly used workflows: duplicate dentures (DDs) and occlusion rims (ORs). Materials and methods: Mounted edentulous casts were used to simulate a completely edentulous patient. These casts were used in two workflows: (1) DD workflow where complete dentures were fabricated and relined (n = 15), and (2) OR where final impressions and ORs were constructed (n = 15). Relined dentures and ORs with fiduciary markers were then scanned and virtually articulated, then exported as STL files. A scan of the articulated casts (simulated patients) with fiduciary markers embedded was also exported as an STL file and used as a control. STL files for each workflow were superimposed over the control and analyzed in 3D inspection software (Geomagic Control X, 3D Systems, NC) for deviations (mm) at three different locations. Average 3D deviations were compared among the groups using a two‐way ANOVA (α—0.05). Results: The average deviation for OR was significantly larger than DD at all locations of measurement [F = 46.00, p < 0.0001]. The majority of the measurements (98.9%) had a positive deviation value, indicating increased OVD. The overall deviation for the OR group from the control was 0.72 ± 0.13 mm versus 0.45 ± 0.23 mm for the DD group. There was no difference in deviation between the points of measurement and no interaction between the location and method [F = 0.02, p < 0.98]. Conclusions: The DD workflow exhibited less deviation in the transfer of OVD than the OR workflow. However, the deviation was small and may not be clinically significant. [ABSTRACT FROM AUTHOR]

Worn denture teeth continue to be a significant complication with implant‐supported prostheses. This article discusses a case report that used an intraoral scanning system to restore an existing maxillary implant‐supported prosthesis with significant posterior occlusal wear. IPS e.max (Ivoclar Vivadent, Schaan, Liechtenstein) restorations were fabricated and cemented to the prepared posterior denture teeth to re‐establish the occlusal vertical dimension and to help prevent further wear of the occlusal surfaces. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the survival rate of full‐coverage tooth‐supported fixed prosthetic restorations, single crowns (SCs), and fixed dental prostheses (FDPs), taking into consideration the potential influence of tooth‐vitality, presence and type of post, and type of prosthetic restoration material. Materials and methods: In October 2022, two authors independently conducted a search in PubMed, Web of Science, and Scopus electronic databases as well as a hand search to identify clinical human studies on full‐coverage SCs and FDPs supported by vital and/or non‐vital abutments and/or a combination of both, with a minimum observation period of 24 months. Results: Out of 4198 studies identified through the database search and 22 through hand searching, 26 studies fulfilled the inclusion criteria and were included in the analysis of the present systematic review. Included studies scored six points and more according to Newcastle‐Ottawa Scale (NOS). The highest estimated 5‐year survival rate was observed for (metal‐ceramic and all‐ceramic) SCs on vital teeth (98.3%; 95% CI [98.1, 98.6%]) and all ceramic SCs on non‐vital teeth with fiber post (95.0%; 95% CI [94.5–95.4%]). Metal‐ceramic SCs on vital teeth (97.1%; 95% CI [95.6–98.7%]) showed a statistically significant higher estimated 5‐year survival rate compared to metal‐ceramic SCs with cast metal post (90.7%; 95% CI [87.4–94.0%], P < 0.001), fiber post (91.3%; 95% CI [90.9–91.6%], P < 0.001) and without post (85.7%; 95% CI [80.7, 90.6%], P < 0.032). All‐ceramic SCs with fiber post had a statistically significant higher estimated 5‐year survival rate (95.0%; 95% CI [94.5–95.4%]) compared to metal‐ceramic SCs on non‐vital teeth with fiber post (91.3%; 95% CI [90.9–91.6%], P < 0.001). SCs (all‐ceramic and metal‐ceramic) with fiber post had a statistically significantly higher estimated 5‐year survival rate of (92.7%; 95% CI [92.4–92.9%]) than SCs made of metal‐ceramic and retained by cast metal post (90.7%; 95% CI [87.4–94.0%], P < 0.001). For FDPs, the 5‐year survival rate was significantly higher for FDPs on vital abutments (84.9%; 95% CI [75.9, 93.9%]) compared to FDPs retained by non‐vital abutment/s (81.3%; 95% CI [80.3, 82.2%], P = 0.049) irrespective to presence, type of post, and FDPs material. The results are limited by the limited number of studies and the presence of uncontrolled confounding clinical variables. Conclusions: Within the limitations of the study, tooth vitality is suggested to contribute positively to the survival of SCs and FDPs. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of immersion in disinfecting solutions on the color stability of denture base resins and artificial teeth obtained by 3D printing. Materials and methods: Forty discs (15 × 3 mm) were obtained for each group: Lucitone 550 and Cosmos Denture 3D (denture base resins), Duralay and Cosmos TEMP 3D (artificial teeth resins). The discs were immersed in disinfectant solutions: Corega Tabs, 2% chlorhexidine digluconate, 0.25% sodium hypochlorite, and distilled water. Color measurements were obtained with a spectrophotometer before immersion in disinfectants and after the simulated periods of 6 and 12 months. Data (ΔE00) were submitted to mixed three‐way ANOVA and Bonferroni post‐test. Results: For denture base resins, Cosmos Denture 3D showed greater color change regardless of the solution and immersion time. The immersion time of 6 months influenced the color change of the denture base resins regardless of the disinfectant solution. For the artificial teeth resins, the immersion time of 12 months showed a significant color change when compared to 6 months. Cosmos TEMP 3D showed greater color change for all solutions, except for 0.25% sodium hypochlorite. Duralay resin showed greater color change in 2% chlorhexidine, regardless of immersion time. Conclusions: For denture base resins, the immersion time significantly changed the color regardless of the solution. For artificial teeth resins, Cosmos TEMP 3D showed greater color changes in all solutions when compared to Duralay, except for 0.25% sodium hypochlorite. Chlorhexidine digluconate significantly changed the color of Duralay. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the tendency of movement, stress distribution, and microstrain of single‐unit crowns in simulated cortical and trabecular bone, implants, and prosthetic components of narrow‐diameter implants with different lengths placed at the crestal and subcrestal levels in the maxillary anterior region using 3D finite element analysis (FEA). Materials and methods: Six 3D models were simulated using Invesalius 3.0, Rhinoceros 4.0, and SolidWorks software. Each model simulated the right anterior maxillary region including a Morse taper implant of Ø2.9 mm with different lengths (7, 10, and 13 mm) placed at the crestal and subcrestal level and supporting a cement‐retained monolithic single crown in the area of tooth 12. The FEA was performed using ANSYS 19.2. The simulated applied force was 178 N at 0°, 30°, and 60°. The results were analyzed using maps of displacement, von Mises (vM) stress, maximum principal stress, and microstrain. Results: Models with implants at the subcrestal level showed greater displacement. vM stress increased in the implant and prosthetic components when implants were placed at the subcrestal level compared with the crestal level; the length of the implants had a low influence on the stress distribution. Higher stress and strain concentrations were observed in the cortical bone of the subcrestal placement, independent of implant length. Non‐axial loading influenced the increased stress and strain in all the evaluated structures. Conclusions: Narrow‐diameter implants positioned at the crestal level showed a more favorable biomechanical behavior for simulated cortical bone, implants, and prosthetic components. Implant length had a smaller influence on stress or strain distribution than the other variables. [ABSTRACT FROM AUTHOR]

Purpose: To assess, clinically, patient satisfaction of additively manufactured complete dentures with intraoral scanning and hybrid cast digitization in comparison with conventional complete dentures. Materials and Methods: Participants who were edentulous in both arches were recruited and received three types of complete dentures (CDs): conventionally manufactured with conventional impression (CC), additively manufactured with intraoral scanning (AMI), and additively manufactured with cast digitization (AMH). Definitive impressions of the edentulous arches were made with medium viscosity polyvinyl siloxane (Hydrorise Monophase; Zhermack, Italy) for the CC group, intraoral scanning (TRIOS 4; 3Shape, Copenhagen, Denmark) for the AMI group, and laboratory scanning of the definitive casts (Ceramill Map400 AMANNGIRRBACH, Pforzheim, Deutschland) for the AMH group. The trial dentures of the CC group were scanned for occlusion registrations of the AMI and AMH groups and were used to guide the designing process (Exocad 3.0 Galway; Exocad GmbH). The AMI and AMH dentures were additively manufactured with a vat‐polymerization 3D printer (Sonic XL 4K; phrozen, Taiwan). Patient satisfaction and clinical outcome were assessed with OHIP EDENT, and 14‐factor criteria, respectively. Statistical analyses were performed with paired sample t‐test and one‐way repeated measure ANOVA for satisfaction, Wilcoxon signed rank test for clinical outcome, and Pearson's r (r) for effect size, with α = 0.05. Results: A total of 20 participants were included. Satisfaction had no statistically significant difference within or among the groups (p < 0.105). Within‐group comparison between the two arches showed no statistical significance for the clinical outcome except for a significantly higher maxillary AMI score (p = 0.01, r = −0.40 with medium effect size). For among group's comparison; AMI had a significantly lower score than CC for the maxillary and mandibular arches (p = 0.01, r = −0.40, medium effect size, and p = 0.003, r = −0.47, medium effect size), and significantly lower score than the mandibular AMH (p = 0.03, r = −0.47, medium effect size), with significantly lower quality in teeth arrangement and retention domains for the AMI, and teeth arrangement for the AMH, in comparison with CC. Conclusions: Patient satisfaction with both types of additively manufactured dentures is comparable to conventional dentures. The comparable overall clinical outcomes between hybrid and conventional dentures indicate that additive manufacturing is an acceptable clinical substitute for the conventional methods. However, additively manufactured dentures made with intraoral scanning have lower clinical quality and retention than hybrid and conventional dentures, particularly for the mandibular arch. Teeth arrangement of both additively manufactured dentures is clinically inferior to the conventional denture. [ABSTRACT FROM AUTHOR]

This case report describes the clinical outcomes of three patients who received removable partial dentures with a completely digitally designed and manufactured metal framework. The initial intraoral impressions were prepared, and the resulting standard tessellation language files were sent to a dental laboratory, where the alloy framework was designed using inLab software and printed using a 3D printer or milled directly from a Co–Cr disc. The quality of fit of the framework was evaluated intraorally to confirm the laboratory design. The acrylic teeth were set, and the definitive partial dentures were delivered after the acrylic resin bases were processed. The follow‐up time was 4 years. No complications or failures related to the components of the partial dentures were observed. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to compare the marginal and internal fit of five‐unit zirconia‐based fixed dental prostheses (FDPs) fabricated using digital scans and conventional impressions. Materials and methods: Nine master models with three zirconia abutments were scanned with an intraoral scanner (test group), and nine conventional impressions (control group) of these same models were also made. The stone casts from these impressions were scanned with a laboratory extraoral scanner (D700, 3Shape, Copenhagen, Denmark). A total of 18 five‐unit zirconia‐based FDP frameworks (test group, n = 9; control group, n = 9) were manufactured. Marginal and internal fit (in μm) were evaluated using the replica method under micro‐computed tomography. Analysis of variance (one‐way ANOVA) and Kruskal–Wallis tests were used to compare continuous variables across two groups. A level of p < 0.05 was accepted as statistically significant. Results: The mean ± standard deviation of the marginal fit was 95.03 ± 12.74 μm in the test group and 106.02 ± 14.51 μm in the control group. The lowest marginal mean value was observed in the test group, with a statistically significant difference compared to the control group (F = 14.56, p < 0.05). The mean ± standard deviation of the internal fit was 103.61 ± 9.32 and 106.38 ± 7.64 μm, respectively, in the test and control groups, with no statistically significant difference (F = 1.56, p > 0.05). The mean values of both groups were clinically acceptable. Conclusions: The five‐unit zirconia‐based FDPs fabricated with digital scans showed better fit than those in the conventional impression group. Within the limitations of this study, these results are encouraging, and continued progress in the digital field should allow for more accurate long‐span restorations. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this systematic review was to compare treatment outcomes in terms of implant survival rate, marginal bone loss, and patient‐reported outcome measures (PROMs) between narrow‐diameter implants and regular‐diameter implants (RDIs) for mandibular implant overdentures (MIOs). Methods: This study was based on the methodology adapted as per Cochrane. Medline, Embase, the Cochrane Central Register of Controlled Trials, Web of Science, and Scopus were searched for pertinent studies published by July 22, 2022. Outcome parameters included in this meta‐analysis were implant survival rate, marginal bone loss, visual analogue scale score for patient satisfaction, and value of oral health impact profile. Results: A total of 782 non‐duplicate articles and 83 clinical study registrations were identified from database and hand searches, of which 26 were eligible for full‐text searches. Finally, 12 publications reporting on 8 independent studies were included in this review. In the meta‐analysis, implant survival rate and marginal bone loss did not significantly differ between narrow‐diameter implants and RDIs. Regarding RDIs, narrow‐diameter implants were associated with significantly better outcomes in general patient satisfaction and oral health‐related quality of life than RDIs for mandibular overdentures. Conclusions: Narrow‐diameter implants have competitive treatment outcomes compared to RDIs in terms of implant survival rate, marginal bone loss, and PROMs. [Correction added on July 21, 2023, after first online publication: The abbreviation RDIs was changed to PROMs in the preceding sentence.] Thus, narrow‐diameter implants might be an alternative treatment option for MIOs in situations with limited alveolar bone volume. [ABSTRACT FROM AUTHOR]

The article discusses a study comparing the shear stress of different denture base resins with bonded denture teeth. The authors express concern about the methodology used in the study, specifically regarding the bonding of teeth to the denture bases. They argue that the failure to follow the validated workflow outlined in the Instructions for Use (IFU) impacted the results. The authors highlight conflicting results from previous studies and emphasize the importance of following the approved IFU for optimal results. They conclude that the protocol described in the study should not be used for patients and recommend following the validated workflow for a stronger bond and high clinical performance. [Extracted from the article]

Purpose: An interdisciplinary clinical review on denture stomatitis formulated by experts from prosthodontics, oral medicine, and oral microbiology is presented. The review outlines the etiopathogenesis, clinical features, and management strategies of denture stomatitis from an interdisciplinary perspective. Materials and methods: English‐language articles relating to the definition, incidence, gender distribution, geographical distribution, etiology, pathogenesis, symptoms, signs, treatment, and prognosis of denture stomatitis were retrieved via electronic literature search. Relevant articles were summarized for this manuscript with a view toward providing pragmatic information. Results: Denture stomatitis represents a very common, multifactorial infectious, inflammatory, and hyperplastic condition which is primarily caused by poor oral hygiene, poor denture hygiene, and full‐time; mainly night‐time denture wear, bringing about the emergence of advanced Candida‐containing polymicrobial biofilms in close proximity to the host's mucosal tissues. Denture stomatitis shares clinically relevant associations with dental caries, periodontitis, median rhomboid glossitis, angular cheilitis, aspirational pneumonia, and associated mortality. Conclusions: Effective, long‐term treatment of denture stomatitis relies upon sustained patient‐driven behavioral change which should focus on daily prosthesis‐level cleaning and disinfection, removal of dentures at night, every night, engagement with professional denture maintenance, and when required, denture replacement. Antifungal medications offer limited benefits outside of short‐term use due to the emergence of antifungal resistance. For frail, older, medically compromised, and nursing home populations, treatment of denture stomatitis lowers the risk of aspirational pneumonia and associated mortality. [ABSTRACT FROM AUTHOR]

Purpose: To assess the accuracy of fit of complete‐arch printed prosthesis prototypes generated with a digital workflow protocol for completely edentulous jaws. Materials and methods: Forty‐five edentulous jaws (35 patients) underwent intraoral complete‐arch digital scans with the double digital scanning (DDS) technique and the generated standard tessellation language (STL) files were superimposed and imported into computer‐aided design software. After STL merging, each master STL file was used for printing a prosthesis prototype. The primary outcome was the accuracy of fit assessment of the printed prototypes on verified master stone casts. Two experienced clinicians tested the accuracy of fit with radiographs and screw‐resistance tests. Secondary outcomes were the effect of the scan body shape and implant number on the accuracy of fit. Results: Out of the 45 DDS‐generated prosthesis prototypes, 39 presented with accurate fit on verified master stone casts, yielding an 86.70% accuracy of fit. Cylindrical scan bodies led to 100% accuracy of fit (25/25), whereas polygonal scan bodies presented with 70% accuracy of fit (14/20). Four implant‐supported prostheses yielded 100% accuracy of fit (12/12), compared with 25/29 (86.30%) accuracy of fit for the six‐implant‐supported ones. Fisher's exact test was used to assess the effect of different scan body shapes (p = 0.005) and implant number on accuracy of fit. Chi‐squared test was used to assess the association between the number of implants per arch and the accuracy of fit (p = 0.039). Conclusions: Thirty‐nine out of 45 complete‐arch prosthesis prototypes generated with a completely digital workflow presented with clinically acceptable fit. The effect of the scan body design and implant number was statistically significant, favoring cylindrical scan bodies and four‐implant‐supported prostheses. [ABSTRACT FROM AUTHOR]

Surgical procedures on partially edentulous patients for complete arch implant‐supported prostheses involve remaining tooth extraction, alveolar bone reduction, and implant placement. Traditionally, partially edentulous patients undergo multiple surgeries, which extends the healing time and results in an extensively prolonged total treatment timeline. This technical article focuses on the fabrication of a more stable and predictive surgical guide to perform multiple surgical procedures in a single surgical appointment and planning a complete arch implant‐supported prosthesis for the partially edentulous patient. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the trueness of intraoral scanning in 8 commonly seen partially edentulous conditions. Materials and methods: A maxillary dentoform was modified into the 8 commonly seen partially edentulous conditions. Each modification was scanned with a laboratory desktop scanner. Each modification was then scanned 10 times (n = 10) with an intraoral scanner. All scans were exported as STL files and then imported into a surface matching software using the best‐fit alignment method. The dimensional differences between the study STL files from the intraoral scanner were compared to the corresponding reference STL files. The measurements were calculated as the root mean square (RMS) and defined as the trueness of the intraoral scans. In addition to the RMS values, qualitative assessments were completed on the color maps. The color maps produced by the surface matching software were used to visualize the areas of deviation between scans from the intraoral scanner and their corresponding reference files. One‐way analysis of variance (ANOVA), followed by pair‐wise comparisons using Fisher's Protected Least Significant Difference were utilized to compare the differences between the groups in RMS values (α = 0.05). Results: Partially edentulous condition significantly affected the trueness of the intraoral scans. Group 8 (Class IV) had significantly lower RMS (0.1878 ± 0.0455 mm) than all other groups (p < 0.001). Group 2 (Class II) and Group 7 (Class III modification I) are not significantly different from each other (Group 2: 0.5758 ± 0.0300 mm; Group 7: 0.5602 ± 0.0231 mm, p = 0.571), while they both had significantly higher RMS than all other groups (p < 0.001). The remaining groups showed the RMS values were within the range of 0.3001 ± 0.0891 mm (Group 6 – Class III with Long Edentulous Span) and 0.4541 ± 0.1039 mm (Group 1 – Class I). Conclusion: Different partially edentulous conditions affected the trueness of the scans generated from the selected intraoral scanner. Class IV edentulous condition had the highest intraoral scan trueness. It is unknown if RMS values are clinically significant, and the validity of using intraoral scans directly for PRDP fabrication will need further studies. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the significance of the connector type on stress dissemination within the tooth‐implant‐supported fixed dental prostheses in the mandibular posterior region with different combinations of implant diameter and length by means of finite element analysis (FEA). Materials and Methods: Six models of different designs for tooth‐implant fixed dental prosthesis (FDPs) were simulated and divided into two main groups. Implant lengths were 10, 11.5, and 13 mm while implant diameters were 3.7, 4.7, and 5.7 mm. The main difference between the groups was the connector type. Models were evaluated using 3D FEA (Solidworks Premium 2018 × 64 Edition). Group A tooth‐implant FDPs (5.7 mm × 10 mm) had a mesial and distal rigid connector while group B tooth‐implant FDPs (3.7 mm × 10 mm, 3.7 mm × 11.5 mm, 3.7 mm × 13 mm, 4.7 mm × 10 mm and 5.7 mm × 10 mm) had a mesial non‐rigid connector in their design between the pontic and the tooth. Models were analyzed to determine the magnitude of von Misses Stresses at six specific zones (fixed dental prosthesis, bone around distal implant, bone around tooth, cementum, periodontal ligament, implant) under vertical occlusal loading of 100 N after meshing and assigning the material properties. Results: Stress values around the supporting bone were significantly higher in Group B (tooth‐implant FDP with non‐rigid connection) when compared to Group A (tooth‐implant FDP with rigid connection). Also, the stresses measured at the FDP level showed that the rigid connection group (5.7 mm × 10 mm) exhibited 26% lower stress values when compared to the non‐rigid group (5.7 mm × 10 mm). Conclusions: Implant‐tooth FDPs with rigid connector design using the combination of implant diameter and length (5.7 mm × 10 mm) demonstrated a better design modality thus predicting a higher success rate and more longevity than using the non‐rigid connection option. [ABSTRACT FROM AUTHOR]

The purpose of this clinical report was to describe the use of a piezographic impression associated with computer‐aided design and computer‐aided manufacturing (CAD–CAM) for teeth setup and of digital tools for neuro‐musculo–kinetic analyses. An edentulous patient with hemiglossectomy and heavily resorbed mandible consulted for complete denture rehabilitation to improve their masticatory function and speech. Master casts, wax rims, and piezographic impression were scanned for digital prosthetic work. Two digital try‐ins were performed to respect the neutral zone: try‐in 1 with posterior crossbite and try‐in 2 without crossbite. Muscle activity and mandibular kinetics were performed for each try‐in following the MAC2 protocol (six criteria): muscular tone, contraction synchrony, contraction efficiency, interocclusal rest distance, amplitude of mandibular movement, and velocity. Try‐in 2 showed better data than try‐in 1 in all criteria: muscle tone (respectively 71% vs. 59%), contraction synchrony (79% vs. 75%), contraction efficiency (85% vs. 77%), an increase in range of motion of 3.3 mm, and a better velocity (0.35 ± 0.12 s vs. 0.57 ± 0.14 s, p = 0.008). The piezographic impression, in combination with CAD–CAM, allowed the comparison of two prosthetic designs and the selection of the try‐in with the best neuro‐musculo–kinetic results. [ABSTRACT FROM AUTHOR]

Purpose: To test the fracture resistance of maxillary canine to canine fixed partial denture with four missing incisors, with increasing anterior‐cantilevers of the pontics and varying connector sizes. Materials and methods: Two 3D‐printed titanium alloy (Ti6Al4V) models mimicking a maxillary canine to canine fixed partial denture (FPD) with four pontics replacing the incisors were used as master models. Zirconia FPDs were digitally designed and milled with two different connector sizes (9 and 12 mm2) each with three different anterior cantilevers (7, 10, and 13 mm) accounting for 6 test groups. Seven samples were milled for each group generating a total of 42 samples. The zirconia FPDs were cemented on the titanium model using resin modified glass ionomer cement and the model fixated to a variable angle vice. A sinusoidal cyclic waveform load from 50 to 280N was applied using a universal testing machine at a frequency of 30 cycles per second and a total of 5 million cycles. Results: The results of Fisher's exact tests showed that the difference in the proportion of fractured versus nonfractured fixed partial dentures was not statistically significant when comparing the 9 with the 12 mm2 connector size (p = 1.00), as well as when comparing the six test groups (p = 0.2338); on the other hand, it proved to be statistically significant when comparing the 7 mm cantilever with the 10 and 13 mm cantilevers combined (p = 0.0407) indicating that a 7 mm anterior spread of the pontics showed a significantly greater proportion of fixed partial dentures that fractured. Conclusions: Fracture susceptibility was not a function of cantilever length in this testing configuration for anterior FPDs. Retainer crown thickness seems to be a more important parameter than connector size thickness. Based on the results, a smaller connector size (9 mm2) can be used to improve the esthetics of pontics in long span anterior FPDs. [ABSTRACT FROM AUTHOR]

Purpose: To assess the accuracy of fit of prosthesis prototypes fabricated via a complete digital workflow protocol with a reverse scan body skipping intraoral scanning for implant data acquisition. Materials and methods: A maxillary stone cast with four multiunit abutment implant analogs (Screw‐Retained Abutments, Institut Straumann AG, Basel, Switzerland) with adequate anteroposterior spread simulated a common clinical patient situation. This stone cast served as the master cast and an interim screw‐retained prosthesis was fabricated on it. Novel reverse scan bodies were connected to the interim prosthesis, and extraoral scanning was performed with a white light intraoral scanner. The produced standard tessellation language (STL) files were then imported to computer‐assisted design software and after the digital design, the STL file was exported to a computer‐assisted machining milling machine and a three‐dimensional (3D) printer to produce a total of 50 milled and 50 printed fixed complete denture prototypes, respectively. Two clinicians assessed the accuracy of fit of each digitally fabricated prosthesis prototype on the master cast, utilizing the screw‐resistance test and radiographic evaluation. Out of the 100 prototypes, 94% (94/100) were fitting accurately. Fisher's exact test was used to test the difference among the groups. The test revealed statistically significant results (p = 0.027). Results: Out of the 50 digitally fabricated milled prosthesis prototypes, 50 (100%) presented with accurate fit under in vitro assessment. Out of the 50 digitally fabricated 3D printed prototypes, 44 (88%) presented with accurate fit under in vitro assessment. Conclusions: Accurately fitting digitally fabricated prosthesis prototypes can be milled after extraoral scanning with reverse scan bodies without intraoral implant data acquisition. [ABSTRACT FROM AUTHOR]

Purpose: Prosthetic cleansing solutions have been reported to cause retention loss in implant locator attachments due to the chemical alterations of these attachments. This study aimed to investigate the effects of different denture cleansing solutions on attachments with different retention values. Materials and methods: In this study, 160 polyetheretherketone locator attachments were divided into 4 groups according to their attachment retention values (yellow, pink, clear, and violet). Forty attachments from each group were soaked in four different cleansing solutions (n = 10). The attachments from the four groups were immersed in water, sodium hypochlorite, Corega, and Protefix solutions for a period equivalent to 6 months, according to the manufacturer's recommendations. The locator attachments were then subjected to testing using a universal testing machine. Maximum load to dislodgement according to different solutions was evaluated by one‐way ANOVA test. Statistical significance was set at p < 0.05. Results: The effect of denture cleansing solutions on the retentive values of attachments was statistically significant (p < 0.001). Among all cleansing solutions, the highest retention value was found in the violet attachments, and the lowest retention value was found in the yellow attachments. The lowest retention value (0.72 ± 0.05 MPa) was observed when the yellow attachments were immersed in Protefix solution, and the highest retention value (1.96 ± 0.15 MPa) was observed when the violet attachments were immersed in the Corega solution. Conclusion: For different colored attachments, different cleansing solutions can be suggested to patients. [ABSTRACT FROM AUTHOR]

Purpose: To retrospectively analyze the success of implant‐assisted removable partial dentures (IARPDs) according to three types of strategic positions in distal extension areas of Kennedy Class I and II arches. Materials and methods: The data included 102 arches in 95 patients with Kennedy Class I/II arches treated with IARPDs with implants in three strategic positions: Type 1a, assisted by P‐1a implants on the anterior area adjacent to the abutment tooth; Type 1b, assisted by P‐1b implants on the anterior area apart from the abutment tooth with or without P‐1a; Type 2, assisted by P‐2a implants on the posterior area adjacent to the natural tooth or P‐2b implants on the posterior area apart from the abutment tooth to modify from Kennedy Class I /II to Class III. The success was defined as the IARPDs without abutment tooth‐related, denture‐related, and implant‐related complications. Kaplan‐Meier curves and the multivariable Cox regression model were used to analyze the success of IARPDs and implants. Results: The overall success rate of IARPD treatment was 66.7%; 77.8% in Type 1a, 60.0% in Type 1b, and 68.0% in Type 2. There was no significant effect of treatment type on success rate of IARPDs. However, there was significant differences at the level of implant supporting IARPDs: 83.3% in Type 1a implants, 62.6% in Type 1b implants, and 73.2% in Type 2 implants. The implants of IARPD's adjacent to the natural tooth abutments (P‐1a and P‐2a) had higher success rates than those away from the natural tooth abutments. Conclusions: Within the limitations of this study, there was no significant difference in the prosthodontic complications of IARPDs depending on the treatment type. However, the success of implants of IARPD is associated with the strategic position. Strategic implant abutments adjacent to the natural tooth had higher success rates than those away from the natural teeth abutments. [ABSTRACT FROM AUTHOR]

Purpose: This study compared the dimensional changes between computer‐aided design and computer‐aided manufacturing (CAD‐CAM) milled complete denture bases (CDBs) and three‐dimensional (3D) printed CDBs. Materials and methods: One maxillary completely edentulous stone model was fabricated with three reference points at the incisive papilla, right molar, and left molar areas marked as X, Y, and Z, respectively. It was scanned to produce a standard tessellation language (STL) file, which was imported to a metal milling machine software to produce the metal model. This metal model was used to fabricate 30 CDBs for analysis. The CDBs were divided into three groups (n = 10 each) according to the fabrication method used as follows: Group 1, CAD‐CAM milled CDBs; Group 2, 3D printed CDBs; and Group 3, conventional compression molded CDBs. The CDBs of all groups were scanned after fabrication, and the dimensional changes in each were evaluated by two methods. The first was the two‐dimensional evaluation method that involved linear measurement of the distances between the reference points (X‐Y, X‐Z, and Y‐Z) of the scanned reference cast and dentures. The second method was the 3D evaluation method that involved the superimposition of the STL files of the dentures on the STL file of the reference cast. Data were calculated and were statistically analyzed using one‐way analysis of variance and Tukey's pairwise post hoc tests. Results: There was a significant difference in the dimensional accuracy between the CAD‐CAM milled, 3D printed, and conventional compression molded CDBs (p < 0.05). Conclusion: The dimensional accuracy of the CAD‐CAM milling system in complete denture fabrication is superior to that of the compression molding and 3D printing systems. [ABSTRACT FROM AUTHOR]

Purpose: The study aimed to compare the tensile bond strength (TBS) of auto‐polymerizing and heat‐polymerizing denture reliners on the conventional (compression‐molding and injection‐molding) and computer‐aided design and computer‐aided manufacturing (milled and 3D‐printed) denture base materials. Materials and methods: Eighty standard dogbone‐shaped specimens were fabricated from four materials: compression‐molding, injection‐molding, milled, and 3D‐printed denture base materials. A 3‐mm cutoff was removed from each specimen at the midsection, and all specimens were reattached with either auto‐polymerizing (n = 10) or heat‐polymerizing (n = 10) reliner. The TBS was measured on the universal testing machine. A scanning electron microscope (SEM) was used to examine the fractured surfaces at cross sections to determine the dominant failure mode in each group. Two‐way ANOVA was used to examine the effects of denture base material and reliner on the TBS (α = 0.05). Weibull survival analysis was also used to determine the survival probability curves. Results: Heat‐polymerizing reliner led to a higher TBS than the auto‐polymerizing reliner, except in the compression‐molding (p = 0.573) groups. Compression‐molding denture base material connected with a heat‐polymerizing reliner showed the highest TBS (29.8 ± 6.9 MPa), whereas 3D‐printed denture base material connected with an auto‐polymerizing reliner showed the lowest TBS (7.2 ± 0.9 MPa). The survival probability based on the Weibull model demonstrated that the compression‐molding denture base material connected with either auto‐polymerizing or heat‐polymerizing reliners had the longest survival time to failure, whereas 3D‐printed denture base material relined with auto‐polymerizing reline material showed the shortest survival time to failure. Under the SEM, the compression‐molding groups demonstrated that the failure modes were mixed but predominantly cohesive. The injection‐molding and milled groups showed predominantly adhesive failures at the denture base‐reline material interfaces. The dominant mode of failure in the 3D‐printed groups was cohesive failures within the bonding adhesive. Conclusions: Although the heat‐polymerizing reliner led to a higher TBS than the auto‐polymerizing reliner in most denture base materials, the compression‐molding denture base material can achieve high TBS with both reliners. When the auto‐polymerizing reliner is used with 3D‐printed denture base material, clinicians should be aware of lower TBS value and possible cohesive failures, and the detachment of the reliner from the denture base. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate the bond strength between two types of artificial teeth with a 3D‐printed denture base resin using different bonding agents. Materials and methods: Two types of artificial teeth were evaluated: 3D‐printed (Cosmos TEMP) and prefabricated polymethylmethacrylate (Biotone) bonded to cylinders (2.5 mm in height and 5 mm in diameter) of 3D‐printed denture bases (Cosmos Denture designing by Meshmixer and printed by Flashforge Hunter DLP Resin 3D Printer). Two combinations between denture base and artificial teeth were eveluated: Cosmos Denture – Biotone, n = 30, and Cosmos Denture ‐ Cosmos TEMP, n = 30. For each combination, the specimens were randomly distributed according to the bonding agent: (1) autopolymerized acrylic resin‐Duralay, n = 10; (2) 3D‐printed resin Cosmos TEMP, n = 10; and (3) methylmethacrylate monomer (MMA) + 3D‐printed resin Cosmos TEMP, n = 10, totaling 60 specimens. The application of MMA was done conditioning the tooth surface for 180 seconds; the other agents were applied on the same surface. The virtual design of the 3D‐printed resin teeth was obtained by scanning the first maxillary molar of the prefabricated teeth as the same protocol of cylinders. The control group (n = 10) was a conventional heat‐polymerized denture base resin (Lucitone 550) bonded to the prefabricated resin teeth (Biotone). The shear bond tests were performed by applying a perpendicular force to the artificial tooth – denture base resin, through a chisel at 1 mm/min until failure. Two‐way ANOVA and Bonferroni post hoc tests (α = 0.05) were used for multiple comparisons. Results: For the Biotone tooth, the bond strength was significantly higher using MMA + Cosmos TEMP (10.04 MPa), and similar to the control (11.84 MPa, p = 0.484). For the 3D‐printed tooth (Cosmos TEMP), the bond strength using the agents Cosmos TEMP (9.57 MPa) and MMA + Cosmos TEMP (12.72 MPa) were similar to the control (11.84 MPa, p = 0.169 and p = 1, respectively), but different from each other (p = 0.016). Conclusions: From the results, it is recommended to use: MMA + Cosmos TEMP bonding agent for the Biotone tooth; and Cosmos TEMP or MMA + Cosmos TEMP bonding agents for the Cosmos TEMP tooth, both attached to the 3D‐printed denture resin Cosmos Denture. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the flexural strength and Vickers microhardness of different CAD‐CAM denture base materials. Materials and methods: Sixty rectangular specimens (64 × 10 × 3.3 ± 0.2 mm) were fabricated from 3 different denture base materials (G‐CAM, Graphene‐reinforced polymethylmethacrylate, GC), Ivotion Base (Prepolymerized polymethylmethacrylate, IV), and Denturetec (3D‐printed resin, DT) either by using additive (DT) or subtractive manufacturing (IV and GC). Specimens of each group were divided into 2 subgroups (thermal cycled or nonthermal cycled, n = 10/group). Nonthermal cycled specimens were stored in distilled water at 37°C for 24 hours and subjected to 3‐point flexural strength test with a universal testing machine. Thermal cycled specimens were initially evaluated for Vickers microhardness and subjected to thermal cycling (10,000 cycles at 5–55°C). Vickers microhardness values were remeasured, and the specimens were subjected to 3‐point flexural strength test. Data were analyzed by using 2‐way analysis of variance and Bonferroni‐corrected Tukey honestly significant difference tests (α = 0.05). Results: Material type and condition significantly affected flexural strength (p ≤ 0.004), whereas their interaction was nonsignificant (p = 0.778). Overall flexural strength of the materials in decreasing order was GC, IV, and DT (p < 0.001), regardless of the condition. Material had a higher effect on flexural strength (ηp2 = 0.731) than thermal cycling (ηp2 = 0.142). The effect of the interaction between the material type and thermal cycling on Vickers microhardness was significant (p < 0.001). GC had the highest microhardness before and after thermal cycling (p < 0.001). IV had higher microhardness than DT before thermal cycling (p < 0.001). However, DT and IV showed similar microhardness after thermal cycling (p = 0.665). Thermal cycling decreased the microhardness of GC and IV (p ≤ 0.022), whereas its effect on DT's microhardness was nonsignificant (p = 0.538). Material type had the highest effect on microhardness (ηp2 = 0.864) followed by the interaction between the main factors (ηp2 = 0.258). Conclusions: Graphene‐reinforced polymethylmethacrylate had the highest flexural strength and Vickers microhardness values, regardless of thermal cycling. Thermal cycling reduced the flexural strength of all resins. Thermal cycling reduced the microhardness of milled polymethylmethacrylate, but not that of 3D‐printed resin. [ABSTRACT FROM AUTHOR]

Purpose: The strength of 3D‐printed resins is affected by different factors, but review articles clarifying these factors are limited. This review lists the factors affecting the strength of 3D‐printed resins and the possible correlations between them to answer the study question: What are the factors affecting the flexural strength of 3D‐printed resins? Methods: A database search (PubMed, Google Scholar, and Scopus) was performed, limited to English‐language publications between 2010 and February 1, 2022. The Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines were used for study selection. The modified Consolidated Standards of Reporting Trials (CONSORT) checklist was used to determine the risk of bias of the included studies in this review. The data analysis was descriptive due to the presence of many variables in the included studies. Results: Out of 123 studies, 26 were reviewed for full‐text analysis, and 19 met the inclusion criteria and were thus included in this systematic review. The included studies were divided according to the investigated resin: 5 studies tested provisional restorations, seven tested denture base resins, 2 tested occlusal devices, 3 tested orthodontic appliances, 1 tested denture teeth, and 1 tested surgical guide resins. These studies investigated the flexural strength of 3D‐printed resins, with different factors, such as reinforcement with fillers or nanofillers; printing orientation, angulation, and directions; post‐polymerization time and temperature; third‐party printing (switching between printers and materials); printing layer thickness; and post‐printing rinsing time. Most factors significantly affected the flexural strength of 3D‐printed resin. Conclusions: The strength of 3D‐printed resins could be improved with one or more of the following factors: filler or nanofiller addition; printing orientation, angulation, or directions; printing layer thickness; and post‐polymerization time and temperature. However, further studies combining these factors are recommended. [ABSTRACT FROM AUTHOR]

Purpose: Studies comparing tensile bond strength of various soft and hard denture liner materials to conventionally and additively manufactured denture base resins are lacking. The purpose of this study was to investigate the tensile bond strength between chair‐ and laboratory‐side soft and hard relining materials and denture‐base materials produced by additive manufacturing and conventional methods. Materials and methods: A total of 120 dimethacrylate‐based additively manufactured and polymethylmethacrylate (PMMA)‐based conventionally fabricated dumbbell‐shaped denture‐base resins were produced. Heat‐cured laboratory‐side soft reline material, self‐cured chair‐side soft reline material, and self‐cured chair‐side hard reline material were attached to the denture bases. The tensile force was applied to the specimens with a universal testing machine at a crosshead speed of 5 mm/min. The obtained data were analyzed with two‐way ANOVA and post hoc Tukey tests. The significance level was set at α = 0.05. Results: The highest tensile bond strength values were obtained in the specimens from the conventionally manufactured base and self‐cured chair‐side hard reline material group, and the lowest was seen in the additively fabricated base and self‐cured chair‐side soft reline material group (p < 0.001). Conventionally manufactured base material's tensile bond strength was higher than that of additively fabricated resin, and self‐cured chair‐side hard reline material's strength was higher than that of laboratory‐side and chair‐side soft reline materials (p < 0.001). However, no significant difference emerged between laboratory‐side and chair‐side soft reline materials (p = 0.405). Conclusions: All the specimens used in the present study had tensile bonding stress values for clinical use. Both denture base resins provided an increased bond to the chair‐side hard relining material, although an improved bond did not emerge for the chair‐side and laboratory‐side soft denture reline materials. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the translucency parameters of traditional, milled, and 3D‐printed denture base materials at 3 different thicknesses and the color masking ability of each material against a metallic background between different thicknesses. Material and methods: A traditional heat‐polymerizing polymethylmethacrylate (PMMA) (H‐Lucitone) material was used as the control group. Two milled pre‐polymerized resin blocks (M‐Lucitone and IvoBase) and five 3D‐printed denture base materials (P‐Lucitone, Dentca LP, Dentca OP, Formlabs, and Kulzer) were used as experimental groups. A total of 240 samples, (n = 30, per material) were fabricated to a final specimen dimension of 12×12 mm and in thicknesses of 1.0, 2.0, and 3.0 mm (n = 10 per thickness/material) according to the manufacturers' recommendations. The color coordinates (L*, a*, b*) in CIELab color space for all specimens placed against a white, black, and metallic background were measured with a spectrophotometer. The translucency parameters (TP00) at each thickness and the color differences between 1 mm and 2 mm (dE00M1‐2) and between 2 mm and 3 mm (dE00M2‐3) against the metallic background were calculated with the CIEDE2000 color matrix. Comparisons between the groups for differences in TP00 were made using One‐way ANOVA separately for each thickness. Comparisons of groups and materials for differences in dE00M1‐2 and dE00M2‐3 were made using Two‐way ANOVA and Fisher's Protected Least Significant Differences (α = 0.05). Results: The TP00 decreased with increasing thickness in all 8 material groups. All 3D‐printed materials, except P‐Lucitone, had higher TP00 than milled pre‐polymerized resin materials (M‐Lucitone and IvoBase), and traditional heat‐polymerizing PMMA (H‐Lucitone) material (P<.001) at all thicknesses. In the 1 mm and 2 mm thickness, heat‐polymerizing acrylic resin (H‐Lucitone) had the lowest TP00, and in the 3 mm thickness, milled acrylic resin (M‐Lucitone and IVOBase) had had lowest TP00 (p < 0.001). All material groups had significantly lower values of dE00M2‐3 than dE00M1‐2 (p < 0.001). The color differences dE00M2‐3 were significantly lower in H‐Lucitone, M‐Lucitone, P‐Lucitone, and IvoBase groups than in other materials, while the color difference of dE00M1‐2 was significantly lower in H‐Lucitone, P‐Lucitone and Dentca LP than other materials (p < 0.001). Conclusions: The results from this study provide clinicians and dental technicians with information regarding the selection of denture base materials to achieve desired color masking outcomes, according to available prosthetic space. Thicker prostheses significantly improved the color masking abilities of denture acrylic resins against a metallic background. In a thickness of 1 and 2 mm, the heat‐polymerizing acrylic resin had a lower translucency parameter and better color masking ability. When the prosthesis thickness reached 3 mm, the milled acrylic resin had a lower translucency parameter and better color masking ability. When compared to the heat‐polymerizing resin and milled acrylic resin materials, except for one 3D‐printing resin (P‐Lucitone), the color masking abilities of the remaining 3D‐printing resin materials were low, regardless of prosthesis thickness. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to investigate the effect of surface treatment and type of composite resin material on the color stability and surface roughness of different denture characterizing composites. Materials and methods: Two nanohybrids [Gradia Plus Gum, (GP) and SR Nexco Paste Gingiva, (SR)] and one microhybrid gingiva‐colored composite resin [Amaris Gingiva, (AG)] were investigated. A total of 120 disk‐shaped samples were prepared, 40 of each material. Samples were divided into two groups (n = 20) for each material according to the surface treatment applied: conventional polishing (control) and coated with a sealant in addition to the surface polishing. All groups were thermocycled. The surface roughness (Ra) was measured using a profilometer after thermal cycling. The samples were then divided into 2 subgroups (n = 10) and stored for 7 days in distilled water or coffee solution. Color differences (ΔE00) were calculated with a spectrophotometer. Results were evaluated with Kruskal‐Wallis and Mann‐Whitney U statistical analysis. Results: The type of denture characterizing composite material and surface treatment method revealed statistically significant differences for the ΔE00 (after immersion both in coffee and distilled water) and the Ra values of denture characterizing composite (p < 0.001 for both). All sealed groups showed significantly higher Ra than the all polished groups. Both in the polished groups and the sealant applied groups, the GP had the highest mean Ra values (0.29 ±0.05 μm and 0.47 ±0.09 μm, respectively). It was followed by SR (0.23 ±0.06 μm and 0.41 ±0.10 μm, respectively), and AG groups (0.20 ±0.06 μm and 0.39 ±0.09 μm, respectively). According to the mean ΔE00 results, all composite groups showed significantly higher ΔE00 values immersed in coffee solutions compared to distilled water. In coffee solutions, the highest ΔE00 was observed in the polished GP (1.90 ±0.40), and the lowest ΔE00 was observed in the polished SR (0.97 ±0.36). The sealed groups showed higher ΔE00 than the polished groups, except for GP. Conclusions: The surface roughness value of sealant applied groups were significantly higher than those of the polished groups. The surface sealant application significantly increased the staining of all composite groups compared to conventional polishing, except for GP. [ABSTRACT FROM AUTHOR]

Purpose: To investigate surface characteristics (roughness and contact angle), anti‐biofilm formation, and mechanical properties (mini‐flexural strength) of computer‐aided design and computer‐aided manufacturing (CAD‐CAM) polymethylmethacrylate (PMMA) polymer, and three‐dimensional (3D) printed resin for denture base fabrication compared with conventional heat polymerized denture base resins. Materials and methods: A total of 60 discs and 40 rectangular specimens were fabricated from one CAD‐CAM (AvaDent), one 3D printed (Cosmos Denture), and two conventional heat polymerized (Lucitone 199 and VipiWave) materials for denture base fabrication. Roughness was determined by Ra value; the contact angle was measured by the sessile drop method. The biofilm formation inhibition behavior was analyzed through Candida albicans adhesion, while mini‐flexural strength test was done using a three‐point bending test. The data were analyzed using descriptive and analytical statistics (α = 0.05). Results: The CAD‐CAM PMMA group showed the lowest C. albicans adhesion (log CFU/mL: 3.74 ± 0.57) and highest mini‐flexural strength mean (114.96 ± 16.23 MPa). 3D printed specimens presented the highest surface roughness (Ra: 0.317 ± 0.151 μm) and lowest mini‐flexural strength values (57.23 ± 9.07 MPa). However, there was no statistical difference between CAD‐CAM PMMA and conventional groups for roughness, contact angle, and mini‐flexural strength. Conclusions: CAD‐CAM milled materials present surface and mechanical properties similar to conventional resins and show improved behavior in preventing C. albicans adhesion. Nevertheless, 3D printed resins present decreased mini‐flexural strength. [ABSTRACT FROM AUTHOR]

Purpose: As the fabrication of computer‐aided design (CAD) milled and 3D printed denture base resins with bonded denture teeth increase in popularity, there is a need for research comparing the shear bond stress of milled and printed denture base resins with bonded denture teeth to that of a conventional heat processed denture base. Materials and methods: Denture base resin specimens (n = 9) were fabricated according to manufacturers' instructions using a novel test design. Two milled (Ivobase CAD PMMA, Ivoclar Vivadent and Polident PMMA, Polident Dental) and two 3D printed (Denture Base LP Resin, Formlabs and Lucitone Digital Print, Dentsply Sirona) materials were used. Conventional heat processed polymethylmethacrylate was used as the control (Lucitone 199, Dentsply Sirona). Denture teeth (VITA Vitapan XL T44, #8, VITA Zahnfabrik) were bonded to their respective bases using denture tooth bonding agent (Ivobase CAD bonding system, Ivoclar). Specimens were aged in water for 600 hours at 37°C and loaded until failure in a Universal testing machine. Shear bond stress was calculated. All specimens were evaluated for mode of failure and select specimens under scanning electron microscope and vertical scanning interferometry. Data were analyzed with one‐way ANOVA followed by Tukey test (IBM SPSS) and fracture analysis performed. Results: Shear stress was highest for the heat processed control (mean = 180 N ±26.76) and Polident test groups (mean = 180 N ± 34.90). Milled specimens were not significantly different from the control (p = 0.076 for IvoBase CAD and 1.00 for Polident), while the printed groups were significantly different from the control (p = 0.012 for Formlabs Denture Base Resin and p = 0.00 for Carbon Lucitone Digital Print). Milled denture base resins performed similarly to heat processed denture base resin and better than 3D printed denture bases. Conclusion: For complete denture wearers, all resin materials used in this study may be clinically acceptable, as the sheer stress for all groups was higher than the reported maximum biting force of complete denture patients. However, for implant retained prostheses, the incorporation of additional retentive features should be considered when bonding denture teeth to printed bases. More research is needed to evaluate methods to increase the bond strength of denture teeth to printed denture base resins. [ABSTRACT FROM AUTHOR]

Purpose: This in vitro study compared the trueness of removable partial denture cobalt‐chromium (Co‐Cr) frameworks fabricated by 3D‐printed pattern casting and those fabricated by selective laser sintering (SLS) with different palate vault depths. Materials and methods: A partially edentulous Kennedy class II mod.1 maxillary model with a deep palatal vault was used, which was modified and duplicated to produce another model with medium palatal vault depth. After model scanning, the partial denture framework was designed using CAD software to fabricate 20 removable partial denture (RPD) frameworks. For each model, two types of frameworks were fabricated. For the 1st type, the 3D‐printed resin patterns were formed using a 3D printer, and then casting was performed (AM‐cast framework). For the 2nd type, a direct metal laser sintering machine was used for the RPD frameworks fabrication (SLS framework). 3D scanning of fabricated frameworks was performed, and the standard tessellation language (STL) file was superimposed over the STL file from the original design, and the average deviation was recorded. Data were statistically analyzed. Results: Two‐way ANOVA test was used, followed by the least significant difference (LSD) for pair‐wise comparisons to estimate any significant differences between groups. The RPD frameworks with high palatal vault depth represent larger discrepancies mean value than that with the medium palatal vault depth with a highly significant statistical difference. SLS shows less deviation than AM‐cast CO‐Cr frameworks with highly significant statistical differences whatever palatal vault depth. Conclusion: RPD metal frameworks fabricated with SLS have better accuracy compared to those fabricated by AM‐cast, regardless of the depth of the palatal vault. [ABSTRACT FROM AUTHOR]