The accuracy of implant positions captured by intraoral scanners (IOSs) is highly dependent on the scanning technique selected. A recently introduced intraoral photogrammetry (PG) system is available; however, its accuracy remains unknown. The purposes of this in vitro study were to compare the accuracy of complete arch implant scans recorded by using a nonsplinting technique and a new commercially available intraoral PG (Freedom Air) and evaluate the influence of calibrated ISB dimension (short and long) on the accuracy of the intraoral PG system. A maxillary stone cast with 6 implant abutment analogs (MultiUnit Abutment Replica) was scanned using a laboratory scanner (T710) to obtain the control scan. Three groups were created based on the scanning technique selected to record complete arch implant scans by using an IOS (Freedom Air): standard ISBs (ISB group), short (S-IPG group) and long (L-IPG group) calibrated ISBs for intraoral PG (n=30). In the ISB group, a standard ISB (AB-SR-01 IPD) was tightened on each implant abutment. Then, scans were obtained by using the selected IOS. The standard ISBs were then retrieved. In the S-IPG group, a short ISB for intraoral PG (SQ-Type) was tightened into each implant abutment, follow by the acquisition of scans using the specific scanning tip for intraoral PG of the IOS device. Afterwards, the 2 ISBs of the first molar positions were retrieved. In the L-IPG group, a long calibrated ISB for intraoral PG (L-Type) was tightened into the 2 implant abutments of the first molar positions. Lastly, implant scans were recorded using the intraoral PG scanning tip of the IOS. Euclidean linear and angular measurements were computed among the 6 implants. The measurements acquired in the control scan were used to measure discrepancies with each experimental scan. One-way ANOVA and Tukey tests were used to analyze trueness. The Levene test was used to examine precision (α=.05). Linear trueness (P<.001) and precision (P<.001) discrepancies and were found. The L-IPG group obtained the best linear trueness, followed by the S-IPG group. The ISB group had the worst linear trueness and precision. The L-IPG group obtained the best linear precision, followed by the S-IPG group. Additionally, angular trueness (P<.001) and precision (P<.001) differences were found. The L-IPG group obtained the best angular trueness, followed by the S-IPG group. The ISB group had the worst angular trueness. The L-IPG group obtained the best angular precision, followed by the S-IPG group. The ISB group had the worst angular precision. The implant scanning technique impacted the accuracy of complete arch implant scans captured by using the IOS tested. The intraoral PG technique had significantly better linear and angular trueness and precision than the nonsplinting method. Positioning long calibrated ISB into the most posterior right and left implants improved the accuracy of the intraoral PG system.
The combined application of the vacuum-sealing method and heat treatment has been suggested to be effective in minimizing the deformation of 3-dimensionally (3D) printed castable resin patterns during denture framework fabrication. The duration of the optimum heat-treatment remains unclear. This study aimed to evaluate the effect of heat-treatment duration on the trueness and precision of castable resin patterns for denture frameworks printed by digital light processing (DLP). A simplified major connector design was created digitally on a definitive cast simulating the maxillary palate. Thirty-five specimens were printed using a DLP printer and were divided into 5 groups (n=7). In the control group, the specimens were rinsed, vacuum-sealed with a cast, and postpolymerized. In the experimental groups, the specimens were rinsed, vacuum sealed with the cast, and then subjected to heat treatment in 90 °C water for 5, 10, 15, or 20 minutes, followed by postpolymerization. The specimens were scanned to obtain digital data for evaluating trueness and precision based on the calculation of root mean square (RMS) values. The 1-way analysis of variance (ANOVA) and Games-Howell post hoc tests were used to assess differences between groups for trueness (α=.05). The pairwise RMS values for precision were summarized at the group level by calculating the mean and standard deviation. Regarding trueness, the control group showed significantly higher RMS values than the 5-, 10-, 15-, and 20-minute groups (all P<.001). Moreover, the 5-minute group exhibited significantly higher RMS values compared with the 10- (P=.008), 15- (P=.013), and 20-minute (P=.011) groups. For precision, the 10-minute group showed the lowest mean RMS value. Heat treatment combined with the vacuum-sealing method significantly improved the trueness of the DLP printed resin patterns. Heat treatments of 10, 15, and 20 minutes demonstrated better trueness than the control and 5-minute groups. In addition, the 10-minute heat treatment yielded the lowest mean RMS value for precision among the tested conditions. These results suggest that a 10-minute heat treatment may represent a favorable postprocessing duration under the conditions evaluated.
Intraoral scanners (IOSs) have been widely used for the digital fabrication of 1-piece endodontic crowns, but the effect of pulp chamber geometry associated with chamber depth and axial wall configuration on scan accuracy performed with different IOSs is not yet clear. The purpose of this in vitro study was to evaluate the influence of pulp chamber design and IOS type on the accuracy of digital scans for 1-piece endodontic crown preparations. Four experimental models (A3, A5, NA3, and NA5) were prepared with 2 pulp chamber depths (3 and 5 mm) and 2 axial wall configurations (with or without axial walls). Each model was scanned 11 times with 2 different IOSs (TRIOS 5; 3Shape and iTero Element 5D; Align Technology), yielding 88 scans. A metrology-grade desktop scanner was used to obtain reference scans. Trueness was assessed via the 3-dimensional (3D) comparison (Geomagic Control X 2022.3;3D Systems) of reference scans and test scans by using the root mean square (RMS) method. Two-way nonparametric factorial analysis of variance ANOVA with the aligned-rank transform (ART) was used to examine the effects of factors and their interactions. Post hoc pairwise comparisons were performed using the estimated marginal means (EMMs) of the aligned ranks with Bonferroni correction (α=.05). Pulp chamber geometry associated with chamber depth and axial wall configuration-scanner combinations led to significant differences in scan trueness (P<.001). The lowest RMS values were observed when the axial wall was present (A3 and A5) and scanned with iTero (15.7 ±1.3 and 17.2 ±2.7 µm), whereas the highest RMS was observed when a no axial wall situation (NA3) was scanned with TRIOS (34.3 ±3.7 µm). iTero enabled a significantly lower mean RMS value than TRIOS in the NA3 situation (P≤.001). When the iTero was used, the NA3 scans exhibited significantly higher RMS values than the A3, A5, and NA5 (P≤.008). When the TRIOS was used, the NA5 and A5 scans exhibited significantly lower RMS values than the NA3 scans (P≤.006). The main effect of pulp chamber geometry on the precision of the scan data was found to be statistically significant (F=3.47, P=.020). The pulp chamber geometry and the interaction between the scanner and the pulp chamber geometry affected the accuracy of scans. Axial wall presence tended to result in higher scan trueness, and iTero scanner enabled higher trueness than TRIOS for the scan of a shallow preparation with no axial wall.
Facial prosthetic rehabilitation following head and neck cancer (HNC) surgery plays an essential role in restoring appearance and function. However, the psychosocial consequences of living with a facial prosthesis remain underexplored and have been poorly addressed within routine care pathways. The purpose of this scoping review was to map and synthesize the existing literature on the psychosocial impact of prosthetic rehabilitation in patients with HNC, identify key themes, and highlight gaps to inform future intervention development. The review followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines and was registered with the Open Science Framework. Comprehensive searches were conducted across 9 electronic databases and 7 nonpeer-reviewed literature sources, with support from a health information specialist. Inclusion criteria focused on studies reporting the psychosocial experiences of patients with HNC using extraoral prostheses. Data were extracted and thematically synthesized using an inductive approach. Thirteen sources met the inclusion criteria: 11 peer-reviewed studies and 2 clinical guidelines. Most studies used qualitative or mixed methods approaches, focusing on adult populations. Four key themes were identified: psychosocial impact of prosthesis use, influence on social relationships, variation in acceptance by prosthesis type, and the role of healthcare professionals and support systems. Patients frequently reported anxiety, shame, and social withdrawal. Central facial prostheses (nasal or orbital) were linked to lower comfort and acceptance. Psychosocial support from clinical teams was often inconsistent or lacking. There is a clear need for a multidisciplinary approach that incorporates tailored psychosocial support. Findings support the development of patient-centered interventions and standardized care pathways.
Results from clinical trials on chronic pain associated with temporomandibular disorders (TMDs) have been traditionally presented as differences in the means of pain intensity scores between the treatment and control group. However, this formulation does not permit any quantification of the treatment effect but is limited to assessing whether a statistically significant difference exists between groups. To address this limitation, a new analysis of our original trial of physiologically oriented occlusal equilibration (POOE) and jaw pain was carried out using a dichotomous outcome: therapy success or therapy failure. All participants in the trial were suffering from moderate to severe chronic jaw pain related to muscular or arthrogenous TMDs, refractory to other conservative or minimally invasive treatments. Participants were randomly assigned to POOE (n=39) or placebo therapy (n=38) groups. POOE was designed to eliminate premature contacts, to obtain balanced occlusion, and to recover physiological alternate mastication function. Adjusted odds ratios were calculated using unconditional logistic regression models in which the independent variable is the treatment received (either POOE or placebo) and the dependent variables are the group differences in change in pain outcomes after 3 and 6 months. The odds of success in pain reduction of POOE compared with those of placebo therapy were calculated. Success was defined as a decrease in pain scores of ≥2 points, while decreases of <2 points, as well as unmodified or increased pain scores were labeled as failure. To measure strong effects of the treatment, in an additional analysis, success was redefined as a decrease in pain of ≥4 points and any other effect as failure. Globally, participants receiving POOE were 2 to 10 times more likely to experience a decrease in jaw pain than patients receiving placebo treatments. The success or failure analysis determined the effectiveness, in terms of mitigation of jaw pain, of occlusal equilibration in the treatment of TMD after 3 and 6 months compared with placebo therapy.
Intraoral scanning for complete arch implant-supported prostheses has been associated with directional deviations that may compromise prosthetic fit. However, the clinical relevance of these deviations and their relationship with scan body height, scanner system, and implant location remain unclear. The purpose of this in vitro study was to evaluate the directional deviations (X-axis, Y-axis, and Z-axis) of multiple implants in intraoral scans of edentulous maxilla, depending on scan body height, scanner type, and implant location. A 3-dimensionally (3D) printed model of an edentulous maxilla with 6 implants, multi-units, and cylindrical polyetheretherketone (PEEK) scan bodies of 3 heights (4.5 mm, 6 mm, and 8 mm) was scanned with 3 intraoral scanners (TRIOS 5 [TR], Primescan [PS], and Infinite [IF]). A total of 144 scans were obtained, and a high-resolution industrial scanner (Artec Micro II) was used to acquire the reference model. Trueness evaluation was conducted using the Geomagic X software program. Directional deviations along the X-, Y-, and Z-axes were calculated for each scan body location. The data were stratified according to scan body height, scanner type, and implant location (molar, premolar, and lateral incisor). Statistical analysis with nonparametric tests (Shapiro-Wilk, Kruskal-Wallis, and post hoc pairwise comparisons) were used to assess differences in absolute deviations among groups (α=.05). Outliers were identified using the z-score method (|z|>3) and removed prior to analysis. Deviations were dichotomized (<90 µm or ≥90 µm), and simple and multiple binary logistic regression models were applied to the X- and Y-axis to evaluate the effects of scanner type, scan body height, and implant location on the likelihood of deviations ≥90 µm. Logistic regression was not performed for the Z-axis because of the absence of sufficient events. Shorter scan bodies showed significantly lower deviations across all scanners (P<.001). Scan bodies of 4.5 mm produced the smallest deviations on the X- and Z-axes, whereas 6 mm yielded the lowest deviations on the Y-axis (P<.001). Scanner performance was axis-dependent, with IF showing the largest deviations on the X- and Y-axes and increased odds of deviations ≥90 µm. Deviations increased with scan body height for all scanners. Implant location showed greater deviations at posterior sites, but this effect was limited after multivariable adjustment. Z-axis deviations remained consistently low. Scan body height and scanner type were the main factors influencing directional deviations in complete arch implant scans. Shorter scan bodies improved trueness, whereas taller scan bodies and IF increased the likelihood of clinically relevant deviations. Implant location had a limited effect after adjustment, and Z-axis deviations were minimal. Selecting appropriate scanning strategies may improve accuracy in complete arch implant rehabilitations.
Designing dental prostheses using computer-aided design software programs can be complex and time-consuming. To address this challenge, artificial intelligence (AI) has been increasingly integrated into the design process. While many studies have evaluated the impact of AI-based applications on dental restoration design, a systematic overview of these findings is lacking. The purpose of this systematic review was to evaluate the design of single tooth-supported restorations using AI-based software programs. A comprehensive literature search was conducted across 4 databases followed by a manual search. Studies investigating factors related to the performance of AI-based design of single tooth-supported restorations were included. The studies were evaluated by 2 independent reviewers, using the Joanna Briggs Institute critical appraisal. In cases of disagreement, a third reviewer was consulted to reach a consensus. After reviewing the full-text articles, 22 studies were included in the analysis. The articles were classified according to 3 identified parameters related to the performance of AI-based designed restorations: Restoration design, time efficiency and biomechanical properties. The restoration design parameter was further analyzed across 7 subcategories: detection of tooth finishing line, marginal fit, internal adaptation, interproximal contacts, occlusion, and esthetic integration. The findings of this review suggest that AI-based design of single tooth-supported restorations holds substantial potential for improving efficiency, internal fit, esthetic integration, and occlusal morphology compared to manual design methods. While the initial results were promising, they were based solely on in vitro investigations; therefore, further clinical validation is required to fully establish the reliability and clinical applicability of AI-generated crowns in routine dental practice.
As experience with intraoral scanners (IOSs) and scientific evidence has grown, factors compromising IOS accuracy have been identified. Limited interdental space between tooth preparations lead to the bridge scanning error, reducing the accuracy of the scanning procedure. However, the interdental space threshold that IOSs are capable to reproduce without presenting this scanning error is uncertain. The purposes of this in vitro study were to compare the ability of 9 IOSs reproducing interdental spaces between 2 adjacent veneer preparations on extracted human teeth before and after postprocessing procedures and to assess the influence of the high definition (HD) scanning mode on this functionality. Two extracted maxillary anterior teeth were obtained. A veneer preparation was completed on each and they were positioned in a stone base without any interdental space between the preparations. Five groups were created depending on the space (0.1, 0.2, 0.3, 0.4, and 0.5 mm) tested and 13 subgroups based on the IOS examined with or without the HD/zoom mode: i700, i700 with HD, i900, i900 with HD, TRIOS 5, TRIOS 5 with Zoom, Primescan, Elite, iTero Lumina, iTero Element 5D Plus, Freedom Air, Sensa, Sensa with HD (n=15). Each specimen was evaluated before and after the automatic postprocessing procedures completed by the IOS program by using these categories: no error, partial error <25%, partial error 25 to 75%, and complete error (>75%). The Fisher test was used to compare the outcome (scanning error) among the subgroups tested (α=.05). For the preprocessing error data, there was nonsignificant association between the 0.1-mm interdental space tested and no scanning error (P=.072). For the remaining groups, the Fisher exact test showed significant association between the interdental space tested and the corresponding scanning error (P<.001). For the postprocessing error data, there is no association between the 0.1- and 0.5-mm interdental space tested and no bridge scanning error (P=.072, P>.999 respectively). For the remaining groups tested, a significant association was found between the corresponding interdental space and the corresponding scanning error (P<.001). The 9 IOSs tested demonstrated different capabilities in reproducing interdental spaces between adjacent veneer preparations before and after postprocessing procedures. The HD/Zoom mode did not influence the interdental space-reproduction threshold of the IOSs tested before or after postprocessing procedures, except for the i700 system in the 0.5 mm space.
Whether the manufacturing protocol (build orientation and sintering schedule) of additively manufactured (AM) zirconia impacts the bond strength compared with subtractively manufactured (SM) zirconia remains unclear. The purpose of this in vitro study was to evaluate the effect of build orientation (45 degrees and vertical), sintering schedule (1-step and 2-step), and resin cement on the shear bond strength (SBS) and failure mode of AM zirconia bonded to dentin compared with that of SM zirconia. One hundred fifty 3Y-TZP zirconia cylinders (Ø2×4 mm) were produced by AM (INNI Cera BCM-W1000) or SM (IPS e.max ZirCAD MT). AM specimens were printed vertically at 90 degrees or at 45 degrees and subjected to 1-step or 2-step sintering; SM specimens were milled and sintered. The specimens were divided into 3 subgroups to be luted to human dentin (n=10) with 3 dual-polymerizing resin cements (SpeedCEM Plus; Ivoclar AG, RelyX Ultimate; 3M Dental, Panavia V5; Kuraray Noritake Dental). Dentin and zirconia surfaces were pretreated per cement and manufacturer protocols. After 24 hours, SBS was measured, and failure modes evaluated. The data were analyzed using 2-way ANOVA to assess the effects of manufacturing technique (AM or SM) and resin cement and using 3-way ANOVA exclusively within the AM group to evaluate the effects of build orientation, sintering schedule, and resin cement, followed by Tukey post hoc tests (α=.05). According to the 2-way ANOVA, zirconia manufacturing technique (AM or SM) did not significantly influence SBS, whereas resin cement had a significant effect (P<.001). Within the AM groups, the 3-way ANOVA revealed that resin cement was also the only factor significantly affecting SBS (P<.001), with no significant effects of build orientation or sintering schedule (P>.05). SpeedCEM Plus (8.9 ±3.7 MPa) showed the significantly lowest SBS and RelyX Ultimate (15.1 ±5.3 MPa), and Panavia V5 (15.7 ±4.9 MPa) yielded similar SBS. No significant difference was found in failure mode between AM and SM zirconia (P=.647), but differences existed between cements (P<.001). Almost all failures (98%) in SpeedCEM Plus groups were adhesive at the dentin-cement interface. The RelyX Ultimate and Panavia V5 groups had approximately 20% adhesive and approximately 50% cohesive failures within dentin. No significant differences in SBS or failure mode were found between AM and SM zirconia. Build orientation and sintering schedule of AM zirconia had no influence on the bond strength of zirconia to dentin, whereas resin cement had a significant effect. In general, SpeedCEM Plus resulted in the significantly lower bond strength of AM and SM zirconia to dentin than did RelyX Ultimate or Panavia V5.
Implant positions can be recorded by using intraoral scanners (IOSs) or photogrammetry (PG) methods. Although the literature has assessed the accuracy of these scanning techniques, further investigation is needed as the technology continues to evolve. The purpose of this in vivo study was to compare the accuracy of complete arch implant scans recorded by using a noncalibrated implant scan body (ISB) method (IOConnect) or an app-based PG (T-Marker). A patient with 4 implants with 4 abutments (MultiUnit Abutment) participated in the study. A scan body was tightened into each implant abutment, and 3 scans were obtained (reference) using an extraoral PG (Micron Mapper). Two groups were developed based on the technique selected to record implant scans: a noncalibrated ISB system (IOConnect) and an app-based (T-Marker) PG. In the IOConnect group, an ISB was hand-tightened into each implant abutment followed by capture of the scans using an IOS (TRIOS 5). In the app-based group, a scan body (T-Marker scan body) was tightened into each implant abutment followed by recoding the scans using an app (T-Marker) and a tablet (iPad Pro). The average of the linear and angular measurements obtained among the 3 reference scans was used as a reference to calculate discrepancies with the same measurements obtained on each specimen. The independent samples t test was used to analyze trueness. The Levene test was used to analyze precision (α=.05). Significant differences were found among the linear (P=.023) and angular (P<.001) trueness discrepancies between the groups. The T-Marker group obtained better linear and angular trueness than the IOConnect group. Significant angular (P<.001) precision discrepancies were shown between the groups. The T-Marker group (mean of 0.02 degrees) had a significantly better angular precision than the IOConnect group (mean of 0.07 degrees). The implant scanning technique impacted the accuracy of complete arch implant scans. However, both techniques may provide a reliable method of capturing implant positions.
The Quality of Masticatory Function Questionnaire (QMFQ) is a subjective instrument used to assess patient-reported outcome measures. The reliability of the Spanish version (QMFQ Sp) has not yet been established. Furthermore, changes in QMFQ Sp and the Oral Health Impact Profile (OHIP-14) following the replacement of missing teeth with partial removable dental prostheses (PRDPs) may help clinicians justify this treatment option to patients. This research aimed to determine the reliability of the QMFQ Sp and changes to the QMFQ Sp and OHIP-14 after the insertion of PRDPs. In total, 10 controls were included for test-retest assessments of the QMFQ Sp, and 26 partially edentulous patients were included to evaluate changes in QMFQ Sp and OHIP-14 after PRDP insertion. The intraclass correlation coefficient (ICC) and Cronbach α test were used to calculate repeatability and internal consistency. The Friedman test with Bonferroni correction was used to compare differences in the QMFQ Sp and OHIP-14 from baseline to 1 week and 3 months after treatment (α=.05). The ICC was 0.91 (P<.001) and Cronbach α 0.93. The QMFQ Sp score reduced significantly from 45.8 to 16 (P<.001), and the OHIP-14 reduced significantly from 7.9 to 3.5 (P<.001) after the 3-month adaptation period to the PRDP. The QMFQ Sp exhibited excellent repeatability and internal consistency. When rehabilitated with a PRDP, partially edentulous patients perceived significant improvements of 26% and 7% in masticatory ability and oral health-related quality of life, respectively.
Scan bodies that enable the reduction of prosthetic components while maintaining accuracy for digital framework planning are limited and require further investigation. The purpose of this in vitro study was to evaluate the accuracy (precision and trueness) of a dual-function scan body in capturing the angulation and distances of multiple implants in completely edentulous arches. Four implants (CM 4.3×10 mm) were placed in a 3-dimensionally (3D) printed mandibular model, from which a master gypsum cast was fabricated. This cast served as the basis for fabricating an interim prosthesis using conventional techniques. The master cast was scanned with a laboratory scanner using a commercial scan body (LS, control group) and a dual-function scan body in its intraoral configuration (B-IS), while the interim prosthesis was digitized via reverse extraoral scanning (B-RS). Interimplant distances and 3D angulations (X, Y, and Z axes) were evaluated using an inspection software program (GOM Inspect). Precision was descriptively assessed using standard deviation and coefficient of variation, while trueness was evaluated through directional delta values between laboratory and Bioscan scans using paired t tests (α=.05). Interimplant distance measurements demonstrated comparable precision among scanning methods, with no relevant differences in variability. Trueness analysis revealed similar distance deviations between B-IS and B-RS scanning. Implant angulation measurements also exhibited comparable precision across the 3D axes. Regarding trueness, significant differences between B-IS and B-RS were observed for the X axis overall, as well as for the Z axis and angular planes (XZ and YZ) of one implant (P<.05). The dual-function scan body demonstrated adequate precision and trueness in capturing implant distance and angulation, with localized limitations in the trueness of vertical and horizontal angulations.
Zirconia has been widely used for frameworks of fixed dental prostheses (FDPs). Polyetheretherketone (PEEK) is a relatively new high-performance polymer. Currently, laboratory data comparing their performance are sparse and limited. The purpose of this systematic review was to compare the in vitro mechanical and interfacial performance of PEEK versus zirconia FDP frameworks. The PubMed, ScienceDirect, Scopus, Cochrane Library and Google Scholar databases were searched up until March 2025. Studies were included if they were in vitro studies directly comparing PEEK and zirconia FDP frameworks. Outcomes reported by studies included fracture strength, marginal gap, and shear bond strength. Risk of bias assessments were completed using the Quality Assessment Tool for In Vitro Studies (QUIN). Meta-analyses (RevMan 5.4) were performed using random-effects models (α=.05). The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework was used to determine certainty of evidence. Fourteen studies were included in the review. Significantly greater fracture strength values were reported for zirconia than PEEK (pooled effect size -1.77; 95% CI -2.52 to -1.02; P<.001; I²=95%). A lower marginal gap was also shown for zirconia compared with PEEK, although PEEK had higher shear bond strength than zirconia. High methodological heterogeneity was seen among studies and the certainty of evidence was low. Zirconia FDP frameworks exhibited higher fracture resistance while PEEK had more favorable bonding behavior in vitro. Results for marginal fit were varied. Since these were in vitro observations of material characteristics, these results should be viewed as hypothesis generating and not as predictors of clinical performance. Clinical research is necessary to validate these results.
The combined effect of the arch scanned, recording level (implant versus multiunit), and recording technique on the trueness and fit of complete arch implant-supported fixed dental prostheses (CAISFDPs) is not well known. This study aimed to investigate how the recording level, recording technique, and dental arch affect the trueness and fit of CAISFDPs. Maxillary and mandibular casts with 2 straight anterior and 2 tilted posterior implants (4.5×12 mm) were digitized using an industrial scanner (Artec Micro II). Recordings were made either digitally using an intraoral scanner or conventionally using an open-tray technique, either multiunit abutment or implant level (n=7). Laser-sintered titanium frameworks were fabricated. The framework trueness and average gap values were analyzed for the effect of recording type, level, and arch by using a metrology-grade software program (Geomagic Control X). The correlation analyses between trueness and average gap values were performed using the Pearson correlation test (α=.05). Recording level (P>.79), recording technique (P>.74), and their interaction had no significant effect (P>.99) on mandibular framework trueness. Frameworks fabricated from abutment-level recordings had lower RMS values than those fabricated from implant-level recordings (P<.001). In contrast, no significant differences were observed between digital scans and conventional recordings at either the implant or abutment level (P>.05). Maxillary framework trueness was not influenced by the recording technique (P>.05). For the maxilla, digital scans resulted in lower average gap values than conventional recordings (P=.005). The average gap values ranged between 40.1 and 242.1 µm. A negative correlation was observed between framework overall trueness and average gap values for mandibular digital scans (r=-.821, P=.023). Digital abutment- and implant-level scans resulted in high manufacturing trueness and fit in both arches, comparable with those of frameworks manufactured by using conventional recordings.
Objective dental esthetic indices have been commonly used in prosthodontic outcome assessment; however, their integrated validation against patient-reported psychosocial outcomes and social-perception ratings remain limited. The purpose of this cross-sectional multicenter study was to externally validate the Dental Esthetic Screening Index (DESI) and investigate the mediating role of social perception in the relationship between objective esthetics and patient satisfaction. The study included 150 adults who received anterior maxillary esthetic prosthodontic treatment. Standardized smile photographs were evaluated using DESI by calibrated prosthodontists. Participants completed the Psychosocial Impact of Dental esthetics Questionnaire and the Patient Global Impression of Satisfaction scale. Lay observers independently rated smile attractiveness and social attributes. Reliability was assessed using intraclass correlation coefficients and the Cronbach alpha. Associations were evaluated using correlation and regression analyses. Diagnostic performance was assessed using receiver operating characteristic analysis. Mediation analysis evaluated indirect effects of social perception (α=0.05). DESI demonstrated excellent interexaminer reliability (ICC=0.88). Higher DESI scores were strongly associated with greater psychosocial impact (r=0.89; P<.001) and lower patient satisfaction (r=-0.84; P<.001). Poorer objective esthetic scores were significantly associated with reduced social-perception ratings (P<.001). DESI showed excellent discrimination for identifying high psychosocial burden (AUC=0.947) and good accuracy for identifying low satisfaction (AUC=0.908). Social perception partially mediated the DESI-satisfaction relationship, accounting for approximately one-third of the total effect. DESI demonstrated strong external validity across objective, patient-reported, and social-perception outcome domains and may support comprehensive esthetic outcome assessment in prosthodontic practice.
The influence of postprocessing cleaning solutions on the trueness and fit of additively manufactured (AM) definitive crowns fabricated from different photopolymer resins remains unclear. The purpose of this in vitro study was to evaluate how different postprocessing cleaning solutions affect the fabrication trueness, marginal quality, and intaglio fit of crowns fabricated from 2 photopolymer resins using additive manufacturing. Ninety-six crowns were printed using either a urethane acrylate (UA)-based resin or a composite resin (CR) and then subdivided into 4 cleaning groups: ethanol (96%), isopropanol (98%), water-based solution, and methyl ether-based solvent. Each crown underwent digital surface scanning, and trueness was measured by using the root-mean-square (RMS) metric for occlusal, external, intaglio, marginal, and overall surfaces. Intaglio fit was assessed by using a triple-scan protocol (TSP) to measure average gap values (AGVs). Statistical analyses included the Shapiro-Wilk test, Generalized Linear Models (GLMs) for trueness and AGVs, Kruskal-Wallis and Mann-Whitney U tests for margin quality, and Spearman rank correlation for association analysis (α=.05). Significant differences were found for both resin type and cleaning solution (P<.001). CR crowns showed higher trueness than UA crowns across all outer surfaces (P<.023), with the UA-S group exhibiting the lowest trueness values. Alcohol-based cleaning was associated with higher marginal trueness (P<.001), with CR-E and CR-I showing the highest marginal trueness values (27.3 ±6.4 and 26.9 ±6.2 µm; P<.015). AGVs were also affected by the cleaning solution (P<.001). Water-based and methyl ether-based solvent-cleaned groups showed smaller AGVs, indicating better intaglio fit, whereas crowns cleaned with ethanol or isopropanol showed larger AGVs. AGVs were negatively correlated with intaglio trueness (ρ=-0.47) and marginal trueness (ρ=-0.65) (P<.001). Both the cleaning solution and the resin type significantly influenced the trueness and fit of crowns. While alcohol-based solutions were associated with higher marginal trueness, water-based and methyl ether-based solvent cleaning yielded better intaglio fit. Composite resin crowns demonstrated more favorable trueness and margin quality than urethane acrylate crowns.
Finishing and polishing protocols can markedly influence the surface quality of computer-aided design-computer-aided manufacturing (CAD-CAM) restorative materials; however, the performance of synthetic diamond abrasives across different microstructures remains unclear. The purpose of this in vitro study was to evaluate the effects of various finishing and polishing procedures on the surface roughness, gloss, and contact angle of 4 CAD-CAM restorative materials. Eighty rectangular specimens (15×1.5×1.5 mm) were prepared from a polymer-infiltrated ceramic (Enamic), ceramic-reinforced composite resin (Cerasmart), fiber-reinforced composite resin (Trinia), and feldspathic ceramic (Vita Mark II). After standardized grinding with 600-, 800-, and 1000-grit silicon carbide papers, specimens were assigned to 4 groups (n=5): control (C), rubber-cup polishing (RC), rubber-cup polishing followed by diamond polishing paste (RC+DP), and rubber-cup polishing followed by synthetic diamond abrasives (RC+SD). Surface roughness (Ra), gloss, and contact angle were measured using a contact profilometer, glossmeter, and drop-shape analyzer, respectively. Data were analyzed using 2-way analysis of variance and the Tukey post hoc test (α=.05). Both polishing procedure and material type significantly affected surface roughness, gloss, and contact angle values (P<.001), with significant interactions between the 2 factors for all parameters. Trinia exhibited the highest roughness and lowest gloss, whereas Cerasmart and Enamic demonstrated smoother surfaces after polishing. The RC+SD protocol generally produced lower Ra values and higher gloss and contact angles compared with RC and RC+DP (P<.001). Finishing and polishing protocols substantially influence the surface quality of CAD-CAM restorative materials. Synthetic diamond abrasives generally produce smoother surfaces, higher gloss, and increased hydrophobicity. Polishing protocols incorporating synthetic diamond abrasives may be considered a reliable approach across different CAD-CAM restorative materials.
Predicting soft tissue response to hard tissue support is complex. Current methods cannot easily predict the dynamic biomechanical variations between static and active facial states. The purpose of this clinical study was to quantify the biomechanical relationship between a labial augmentation prosthesis (LAP) thickness and sagittal upper lip displacement under maximum smile and rest positions and to evaluate the influence of participant-related variables on soft tissue displacement. Twenty-three participants (mean ±standard deviation age: 27 ±8.71 years; 16 men and 7 women) were recruited. Digital facial scans were acquired using a 3-dimensional facial scanning system under 2 conditions (rest and maximum smile) with LAPs of 1-, 2-, and 3-mm thickness. Facial landmarks were analyzed using a coordinate-based alignment system with a custom algorithm. Measurement reliability, scanner trueness, and precision were verified. Generalized estimating equations (GEEs) were used to assess the effects of LAP thickness, facial expression, and their interaction on upper lip displacement. The Wilcoxon rank sum test was used to evaluate the influence of sex, while Spearman correlation coefficients (ρ) were calculated to assess the influence of other participant-related variables (α=.05). The scanning system demonstrated high trueness (systematic error 0.24 mm) and precision. Upper lip displacement showed a strong linear correlation with LAP thickness (R2>0.98). A significant interaction was found between thickness and facial expression (P=.049); specifically, at the 3-mm thickness, the maximum smile condition resulted in significantly greater displacement (mean ±standard deviation: 3.24 ±0.35 mm) than the rest position (mean ±standard deviation: 2.76 ±0.41 mm). The mean displacement for 1-mm and 2-mm LAP thicknesses were 1.20 and 2.20 mm during maximum smile and 1.08 and 1.92 mm at rest, respectively. Regarding participant-related variables, both age and sex were identified as significant predictors during maximum smile; older participants and women exhibited significantly reduced lip displacement during maximum smile (P<.05), whereas body mass index and other variables showed no significant correlation. Within LAP thicknesses up to 3 mm, upper lip displacement was strongly and linearly correlated with prosthesis thickness. This response was expression-dependent, exhibiting a synergistic increase in displacement at the 3-mm thickness during maximum smile. While the LAP thickness was the primary determinant, older age and female sex were significantly associated with reduced lip displacement during maximum smile.
The marginal gap in ceramic crowns is a critical parameter for the biological integrity and long-term success of restorations. Although computer-aided design and computer-aided manufacturing (CAD-CAM) systems have been reported to provide a more predictable manufacturing process by reducing operator-dependent variability, the evidence comparing the marginal gap of CAD-CAM and conventional methods remains inconsistent. The purpose of this systematic review and meta-analysis was to quantitatively compare the marginal gap of ceramic crowns fabricated using CAD-CAM versus conventional laboratory techniques and to estimate the mean difference between the 2 approaches. A comprehensive search was conducted in the PubMed, Scopus, Web of Science, Embase, the Cochrane Library, and Google Scholar databases without restrictions on year or language. In vitro studies reporting comparative marginal gap values (mean, standard deviation, and sample size) for crowns fabricated with CAD-CAM and conventional methods were included. The pooled effect size was calculated using a random-effects model (DerSimonian-Laird). Heterogeneity was assessed using the Q statistic, I² statistic, and between-study variance (τ²). Publication bias was evaluated using funnel plots and the Egger regression test. Sensitivity analyses were performed using a leave-one-out approach. A total of 16 studies were included in the meta-analysis. The pooled mean difference was not statistically significant (mean difference [MD]=-2.3 µm; 95% confidence interval [CI], -10.6 to +5.9 µm; P=.582). Heterogeneity was substantial (I²=95.2%), largely attributable to the study using microcomputed tomography (µCT), which exhibited lower variance and different distributional characteristics compared with other measurement techniques. Leave-one-out analyses indicated that no single study materially altered the direction or statistical significance of the overall estimate. Importantly, in both groups, all marginal gap values remained below clinically acceptable thresholds (<120 µm). Ceramic crowns fabricated using CAD-CAM and conventional techniques demonstrate comparable marginal gaps. While CAD-CAM systems may reduce cumulative errors and enable a more standardized workflow under certain clinical conditions, meticulously performed conventional techniques by experienced dental laboratory technicians can achieve similarly successful outcomes. Because the marginal gaps were within clinically acceptable limits for both methods, technique selection should not be based solely on marginal gap; rather, broader clinical parameters-such as preparation geometry, material selection, clinical workflow, and operator experience-should be decisive in the decision-making process.
Despite the increased use of direct-to-abutment connections for implant-supported fixed complete dental prostheses (ISFCDPs), limited evidence exists regarding marginal adaptation and internal fit, 2 parameters critical for biomechanical performance. This study evaluated the marginal adaptation and internal fit of zirconia frameworks with direct-to-abutment connections compared to conventional titanium base (Ti-base) connections. A novel method for internal fit assessment using a deep learning artificial intelligence (AI) model was also introduced, and level of agreement with traditional measurements was assessed. Internal fit was compared across the 3 designs using both traditional and AI-derived measurements. Zirconia specimens (n=24) were allocated to 3 groups: frameworks with Ti-base and regular screws (n=8), frameworks fabricated direct-to-abutment with regular screws (n=8), and frameworks fabricated direct-to-abutment with modified screws (n=8). Each specimen underwent microcomputed tomography scanning before and after thermomechanical aging (TMA) to assess internal fit and marginal adaptation. A deep learning-based AI segmentation model was developed using an image processing software program and achieved a final validation loss below 0.01, corresponding to a Dice Similarity Coefficient greater than 0.95. This metric indicates high spatial overlap and robust segmentation of the gap and abutment regions. Volumetric measurements were obtained for 1 straight and 1 angled transmucosal abutment per specimen. Specimens were subjected to 1.2 million loading cycles at 90 N, followed by repeated measurements. Ninety-six sites were evaluated before and after TMA. Two measurements each for straight and angled abutments for the 3 designs were averaged and difference scores were calculated as post-TMA minus pre-TMA values. Nonparametric statistical tests were applied because of heterogeneity of group variances. Post hoc Mann-Whitney U tests, intraclass correlation and Bland-Altman analyses were conducted (α=.05). Significant differences in marginal adaptation among the 3 groups were identified before and after TMA. The Ti-base group demonstrated significantly superior marginal adaptation compared to both direct-to-abutment groups at both time points (z=3.36, P<.001). Significant differences in internal fit were also observed among the 3 groups before and after TMA. Ti-base group showed significantly improved internal fit relative to both direct-to-abutment groups (standardized Mann-Whitney z values ranged from 3.15 to 3.36, P<.001). Intraclass correlations revealed a significant level of agreement between standardized measurements obtained using conventional and AI-based methods (P<.001), and Bland-Altman plots provided support for concurrent validity of the AI-derived measures of internal fit. Ti-base connections in ISFCDPs demonstrated superior marginal adaptation and internal fit compared to direct-to-abutment connections. Both connection designs achieved clinically acceptable internal fit values. For marginal adaptation, the direct-to-abutment regular screw group exceeded the clinically acceptable threshold of 120 µm. A significant level of agreement was found between standardized traditional and AI-derived measurements of internal fit. Bland-Altman plots supported the concurrent validity of the deep learning AI model.