Effects of extraoral storage time on autologous gingival graft early healing: A split-mouth randomized study.

AIMS: Despite the established use of palatal tissue grafts for mucogingival procedures, there are no studies on the effect of extraoral storage time on graft outcomes. This prospective split-mouth randomized experimental clinical trial aimed to assess whether gingival graft extraoral storage time affects graft healing. METHODS: Standardized grafts were harvested from the palate and stored extraorally for 2 (Control) or 40 (Test) minutes before being placed at recipient beds. Intraoral scans, clinical photographs, and tissue blood perfusion were obtained preoperatively, postoperatively, and at follow-up visits (Days 2 (PO2), 3 (PO3), 7 (PO7), and 14 (PO14)). Healing Score Index (HSI) and wound fluid (WF) biomarkers (angiogenin, IL-6, IL-8 (CXCL8), IL-33, VEGF-A, and ENA-78 (CXCL5)) were also assessed. RESULTS: Twenty-three participants completed all study visits. Extraoral storage time was 2.3 ± 1.1 min and 42.8 ± 3.4 min for C and T grafts, respectively (p < .0001). Recipient beds remained open for 21.4 ± 1.7 min. No graft underwent necrosis or failed to heal by PO14. Minimal volumetric changes were observed, without significant intergroup differences (p ≥ .11). Graft perfusion initially decreased post-harvesting before peaking on PO7 for both C and T grafts, with no significant intergroup differences (p ≥ .14). HSI values progressively increased, with no significant intergroup differences (p ≥ .22). WF analysis revealed detectable levels for all biomarkers tested, without significant intergroup differences (p ≥ .23). CONCLUSION: Extraoral storage time of 40 min has neither statistically significant nor clinically discernible effects on autologous graft revascularization, early healing, or survival, as determined by physiological, wound healing, and molecular parameters.

The Impact of Technology Teaching in the Dental Predoctoral Curriculum on Students' Perception of Digital Dentistry.

The goal was to assess dental students' perception of digital technologies after participating in a CAD/CAM exercise for scanning, designing, and manufacturing computer-aided provisional fixed dental restorations. A survey was conducted among second- (pre-D2 and post-D2), first- (D1, negative control), third-, and fourth-year dental students (D3 and D4, positive controls). Only OSU College of Dentistry students who completed the activity and completed the surveys were included. Seven questions were rated, which evaluated changes in knowledge, skill, interest, the importance of technology availability in an office, patients' perception of technology, the importance of having the technology, and the expected frequency of clinics utilizing the technology. Statistical analysis was performed with a significance level of 0.05. A total of 74 pre-D2 and 77 post-D2 questionnaires were completed. Additionally, 63 D1, 43 D3, and 39 D4 participants responded to the survey. Significant differences were found for "knowledge" and "skill" between the pre-D2 and post-D2 and pre-D2 and control groups (p < 0.001). There was a significant difference between the post-D2 participants and all the controls in terms of "interest" (p = 0.0127) and preference for in-practice technology availability (p < 0.05). There were significant results between the post-D2 participants and all the controls regarding the importance of technology availability in an office (p < 0.001) and the expected frequency of clinics utilizing the technology (p = 0.01). No significance was found for "value of technology to patients" and "the importance of having the technology". The presence of technology in practice and in educational academic environments significantly improved students' interest and perception of their knowledge and skill.

Upper lip characteristics and associated excessive gingival display etiologies in adults: Race and sex differences.

BACKGROUND: This cross-sectional study aimed to examine upper lip (UL) and smile characteristics and soft tissue excessive gingival display (EGD) etiologies (hypermobile upper lip [HUL], altered passive eruption [APE], and short upper lip [SUL]) in a nondental adult population and to analyze interracial (Black and White) and intersex differences. METHODS: Community participants, non-Hispanic Blacks (NHB) and non-Hispanic Whites (NHW), were recruited and examined for UL vertical dimensions at rest and maximum smile and for HUL, APE, and SUL. Associations between gingival display (GD) or EGD and UL anatomical characteristics, HUL, APE, and SUL were analyzed. RESULTS: Participants included 66 NHB and 65 NHW adults. Ergotrid height (greater among NHW; p = 0.019) averaged 14.0 mm. Upper lip vermilion length (ULVL), total UL length, internal lip length, total UL length during smile, and UL mobility averaged 8.6, 22.5, 23.1, 16.6, and 5.9 mm, respectively (all significantly greater in NHB; p ≤ 0.012). SUL prevalence was 4.6%, found only among NHW. Lip length change from rest to smile (LLC) averaged 26.2% (significantly greater in females; p = 0.003). HUL prevalence was 10.7% (NHB 13.1%, NHW 3.5%; p = 0.024). NHB had significantly greater GD (p ≤ 0.017). EGD and APE prevalence (6.9% for both) showed significant interracial and intersex differences (p ≤ 0.014). Multivariate logistic regression analyses indicated that LLC and HUL were the most consistently significant EGD determinants. CONCLUSIONS: UL anatomical and functional characteristics and soft tissue-related EGD etiologies exhibit significant interracial and intersex differences, with UL mobility/hypermobility being the most consistently significant determinant of GD.

Effect of scan powder and scanning technology on measured deviations of complete-arch implant supported frameworks digitized with industrial and intraoral scanners.

OBJECTIVES: To evaluate the suitability of intraoral scanners (IOSs) to analyze the fabrication trueness of titanium complete-arch implant-supported frameworks by comparing with an industrial-grade scanner and investigate how anti-reflective scan powder affects measured deviations. METHODS: Ten titanium complete-arch implant-supported frameworks were milled from a reference standard tessellation language (STL) file. An industrial-grade blue light scanner (ATOS Core 80 (AT)) and three IOSs (Primescan (PS), TRIOS T3 (T3), and TRIOS T4 (T4)) with (PS-P, T3-P, and T4-P) or without (PS, T3, and T4) anti-reflective scan powder application were used to generate test STL (TSTL) files of the frameworks. Reference STL and TSTLs were imported into a metrology-grade analysis software (Geomagic Control X) and whole surface root mean square (RMS) values were calculated. Another software (Medit Link v 2.4.4) was used to virtually isolate marginal surfaces of all STL files and marginal RMS values were calculated by using the same metrology-grade analysis software. A linear mixed effects model was used to compare the transformed deviations of the scans performed by using each IOS (with or without powder) with the deviations of those performed by using the reference AT scanner within each surface, where a Box-Cox type transformation was used for variance stability. Bonferroni corrected post-hoc tests were used to compare conditions within each IOS (α=0.05). RESULTS: All IOSs had significantly higher whole surface and marginal RMS values than AT, regardless of the condition (P≤.002). However, scan powder application did not affect the whole surface and marginal RMS values in scans of tested IOSs (P≥.054). CONCLUSION: Measured whole surface and marginal deviations in all IOS scans performed with or without the use of scan powder were higher than those in AT scans. The application of anti-reflective scan powder did not affect the deviations in scans of tested IOSs. CLINICAL SIGNIFICANCE: Even though deviations measured in the scans of tested scanners were significantly different than those in the reference scanner, the maximum raw mean difference was 37.33 µm and the maximum raw confidence interval value of estimated differences was 47.88 µm, which can be considered clinically small taking into account the size of the frameworks tested. Therefore, tested intraoral scanners may be feasible to scan prostheses similar to or smaller than tested frameworks for fabrication trueness analysis, which may facilitate potential clinical adjustments.

Comparison of intraoral and laboratory scanners to an industrial-grade scanner while analyzing the fabrication trueness of polymer and titanium complete-arch implant-supported frameworks.

OBJECTIVES: To compare the scans of different intraoral scanners (IOSs) and laboratory scanners (LBSs) to those of an industrial-grade optical scanner by measuring deviations of complete-arch implant-supported frameworks from their virtual design file. MATERIAL AND METHODS: Ten polyetheretherketone (PEEK) and 10 titanium (Ti) complete-arch implant-supported frameworks were milled from a master standard tessellation language (STL) file. An industrial-grade blue light scanner (AT), 2 LBSs (MT and E4), and 3 IOSs (PS, T3, and T4) were used to generate STL files of these frameworks. All STLs were imported into an analysis software (Geomagic Control X) and overall root mean square (RMS) values were calculated. Marginal surfaces of all STL files were then virtually isolated (Medit Link v 2.4.4) and marginal RMS values were calculated. Deviations in scans of tested scanners were compared with those in scans of AT by using a linear mixed effects model (α = 0.05). RESULTS: When the scans of PEEK frameworks were considered, PS and T3 had similar overall RMS to those of AT (p ≥ .076). However, E4 and T4 had higher and MT had lower overall RMS than AT (p ≤ .002) with a maximum estimated mean difference of 13.41 µm. When the scans of Ti frameworks were considered, AT had significantly lower overall RMS than tested scanners (p ≤ .010) with a maximum estimated mean difference of 31.35 µm. Scans of tested scanners led to significantly higher marginal RMS than scans of AT (p ≤ .006) with a maximum estimated mean difference of 53.90 µm for PEEK and 40.50 µm for Ti frameworks. CONCLUSION: Only the PEEK framework scans of PS and T3 led to similar overall deviations to those of AT. However, scans of all tested scanners resulted in higher marginal deviations than those of AT scans. CLINICAL SIGNIFICANCE: Scans performed by using PS and T3 may be alternatives to those of tested reference industrial scanner AT, for the overall fabrication trueness analysis of complete-arch implant-supported PEEK frameworks.

Effect of analysis software program on measured deviations in complete arch, implant-supported framework scans.

STATEMENT OF PROBLEM: Implementation of fabrication trueness analysis by using a recently introduced nonmetrology-grade freeware program may help clinicians and dental laboratory technicians in their routine practice. However, knowledge of the performance of this freeware program when compared with the International Organization for Standardization recommended metrology-grade analysis software program is limited. PURPOSE: The purpose of this in vitro study was to evaluate the effect of an analysis software program on measured deviations in the complete arch, implant-supported framework scans. MATERIAL AND METHODS: A total of 20 complete arch, implant-supported frameworks were fabricated from a master standard tessellation language (STL) file from either polyetheretherketone (PEEK) or titanium (Ti) (n=10). All frameworks were then digitized by using different scanners to generate test STLs. All STL files were imported into a nonmetrology-grade freeware program (Medit Link) and a metrology-grade software program (Geomagic Control X) to measure the overall and marginal deviations of frameworks from the master STL file by using the root mean square (RMS) method. Data were analyzed by using the two 1-sided paired t test procedure, in which 50 µm was considered as the minimal clinically meaningful difference (α=.05). RESULTS: When overall RMS values were considered, the nonmetrology-grade freeware program was not inferior to the metrology-grade software program (P<.05). When marginal RMS values were considered, the nonmetrology-grade freeware program was inferior to the metrology-grade software program only when PEEK frameworks were scanned with an E4 laboratory scanner (P>.05). CONCLUSIONS: The use of the tested nonmetrology-grade freeware program resulted in overall deviation measurements similar to those when a metrology-grade software program was used. The freeware program was inferior when marginal deviations were analyzed on E4 scans of a PEEK framework, which was the only scanner-material pair that led to a significant difference, among the 15 pairs tested.

Comparison of maxillary anterior tooth movement between Invisalign and fixed appliances.

INTRODUCTION: This research project aimed to compare the number of maxillary incisors and canine movement between Invisalign and fixed orthodontic appliances using artificial intelligence and identify any limitations of Invisalign. METHODS: Sixty patients (Invisalign, n = 30; braces, n = 30) were randomly selected from the Ohio State University Graduate Orthodontic Clinic archive. Peer Assessment Rating (PAR) analysis was used to indicate the severity of the patients in both groups. To analyze the incisors and canine movement, specific landmarks were identified on incisors and canines using an artificial intelligence framework, two-stage mesh deep learning. Total average tooth movement in the maxilla and individual (incisors and canine) tooth movement in 6 directions (buccolingual, mesiodistal, vertical, tipping, torque, rotation) were then analyzed at a significance level of α = 0.05. RESULTS: Based on the posttreatment Peer Assessment Rating scores, the quality of finished patients in both groups was similar. In maxillary incisors and canines, there was a significant difference in movement between Invisalign and conventional appliances for all 6 movement directions (P <0.05). The greatest differences were with rotation and tipping of the maxillary canine, along with incisor and canine torque. The smallest statistical differences observed for incisors and canines were crown translational tooth movement in the mesiodistal and buccolingual directions. CONCLUSIONS: When comparing fixed orthodontic appliances to Invisalign, patients treated with fixed appliances were found to have significantly more maxillary tooth movement in all directions, especially with rotation and tipping of the maxillary canine.

Assessment of malalignment factors related to the Invisalign treatment time aided by automated imaging processes.

OBJECTIVES: To identify predictors regarding the type and severity of malocclusion that affect total Invisalign treatment duration based on an intraoral digital scan. MATERIALS AND METHODS: The subjects of this retrospective clinical cohort were 116 patients treated with Invisalign. A deep learning method was used for automated tooth segmentation and landmark identification of the initial and final digital models. The changes in the six degrees of freedom (DOF), representing types of malalignment, were measured. Linear regression was performed to find the contributing factors associated with treatment time. In addition, the Peer Assessment Rating (PAR) score and a composite score combining 6 DOF were correlated separately to the treatment time. RESULTS: The number of trays differed between sexes (P = .0015). The absolute maximum torque was marginally associated with the total number of trays (P = .0518), while the rest of the orthodontic tooth movement showed no correlation. The composite score showed a higher correlation with the total number of trays (P = .0045) than did individual tooth movement. Pretreatment upper and lower anterior segment PAR scores were positively associated with the treatment time (P < .001). CONCLUSIONS: There is not enough evidence to conclude that certain types of tooth movement affect the total aligner treatment time. A composite score seems to be a better predictor for total treatment time than do individual malalignment factors in aligner treatment. Upper and lower anterior malalignment factors have a significant effect on the treatment duration.

Effect of printing layer thickness on the trueness of 3-unit interim fixed partial dentures.

STATEMENT OF PROBLEM: Three-dimensional printing has facilitated the fabrication processes in dentistry. However, knowledge on the effect of layer thickness on the trueness of 3D-printed fixed partial dentures (FPDs) is lacking. PURPOSE: The purpose of this in vitro study was to compare the effect of printing layer thickness on the trueness of 3-unit interim FPDs fabricated by using additive manufacturing with that of those fabricated by subtractive manufacturing. MATERIAL AND METHODS: The right first premolar and first molar teeth of a dentate mandibular model were prepared for a 3-unit restoration and then digitized by using an intraoral scanner. A 3-unit interim FPD was designed to fabricate 40 restorations by using either the additive (NextDent C&B MFH) with layer thicknesses of 20 µm (n=10), 50 µm (n=10), and 100 µm (n=10) or subtractive manufacturing technique (Upcera) (milled, n=10). After fabrication, the interim FPDs were digitized by using the same intraoral scanner and were superimposed over the design data by using a 3D analysis software program. Root mean square (RMS) was used to analyze the trueness of the restorations at 4 different surfaces (external, intaglio, marginal area, and intaglio occlusal) and as a complete unit (overall). Data were analyzed with the Kruskal-Wallis and Wilcoxon tests with Bonferroni correction (α=.05). RESULTS: The 100-µm-layer thickness interim FPDs showed the greatest overall (P≤.015), external (P≤.021), and intaglio occlusal (P≤.021) deviations, whereas the milled interim FPDs showed the lowest (P=.001). No significant differences were found among the test groups for marginal RMS (P≥.108). The differences between the 50-µm-layer thickness and 100-µm-layer thickness interim FPDs for the intaglio surface deviations (P=.064) and between the 20-µm-layer thickness and 50-µm-layer thickness interim FPDs for each surface tested were not statistically significant (P≥.108). CONCLUSIONS: The printing layer thickness had a significant effect on the trueness of the additively manufactured interim FPDs. However, subtractively manufactured interim FPDs presented higher trueness than those additively manufactured, regardless of the printing layer thickness.

Comparison of measured deviations in digital implant scans depending on software and operator.

OBJECTIVES: To investigate the effect of 3-dimensional (3D) analysis software and operator on the measured deviations in implant scans. MATERIAL AND METHODS: A combined healing abutment-scan body (CHA-SB) system was digitized with an industrial scanner (ATOS Core 80) to generate a master standard tessellation language file (MRM-STL) and an intraoral scanner (TRIOS 3) to generate 9 test-scan STL files, which were transferred into metrology-grade (Geomagic Control X, GX and GOM Inspect, GM) and nonmetrology-grade (Medit Link, ML) software for deviation analysis. Test-scan STLs were superimposed over MRM-STL and 2 planes passing through the center of the SB were generated. Distance deviations at 8 points on these planes were analyzed by two different operators with similar level of experience. Data were analyzed with analysis of variance and F tests (α=.05). RESULTS: Only model 1 (P=.049) analyzed by operator 2 showed significant differences among tested software, and the highest deviations were measured with GM (P≤.037). However, the difference in values measured with GX and ML was nonsignificant (P=.91). Operator correlation was high (ICC≥.712, P≤.011), except for models 1 (GM, ICC=-.335, P=.813), 2 (GM, ICC=.025, P=.468 and ML, ICC=-.013, P=.507), 6 (GM, ICC=-.085, P=.583), and 8 (GM, ICC=-.386, P=.85). CONCLUSION: The measured deviations in implant scans in all models, except for one, were similar among the tested software, regardless of the operator. The inter-rater reliability of operators while using tested 3D analysis software was overall high. When observed, low inter-rater reliability was mostly with only one of the metrology grade software. CLINICAL SIGNIFICANCE: Nonmetrology-grade 3D analysis software may be a suitable alternative to metrology-grade software to measure the deviations in digital implant scan body scans. When GOM metrology-software is used, measured deviations in implant scan body scans may vary more across operators.

Effect of adhesive system, resin cement, heat-pressing technique, and thermomechanical aging on the adhesion between titanium base and a high-performance polymer.

STATEMENT OF PROBLEM: Even though polyetheretherketone (PEEK) has become popular for various prosthetic indications, a standard adhesive protocol to bond the PEEK to titanium bases has not been yet established. How the heat-pressing technique performs in this respect is also not clear. PURPOSE: The purpose of this in vitro study was to investigate the effect of an adhesive system-cement combination, the heat-pressing technique, and thermomechanical aging on the retention force between titanium bases and PEEK specimens. MATERIAL AND METHODS: Sixty 9×11×20-mm PEEK specimens with a titanium base slot integrated into the design were milled to simulate an implant-supported PEEK framework for a cantilevered fixed prosthesis. The specimens were assigned to 8 groups (n=10) according to the titanium base primer (MKZ or Monobond) and resin cement (DTK or Multilink hybrid) used and with or without thermomechanical aging. Twenty PEEK specimens were directly heat-pressed on titanium bases, and half of the specimens were not subjected to thermomechanical aging (n=10). For nonaged groups, the PEEK specimen complex was tightened to an implant analog and secured on a custom-made pull-off device. Retention forces were measured by using the pull-off tensile test in a universal testing machine, and the maximum tensile bond strength (MPa) was calculated. The aged groups were subjected to 5000 cycles of thermal aging (5 °C to 55 °C), and the specimens were clamped to load the extension (cantilever) for 1 200 000 cycles with 120 N and 200 N at 1.5-Hz frequency. After aging, the pull-off test was performed for those specimens that survived thermomechanical aging. A nonparametric Kruskal-Wallis test was used to determine whether there was a difference among the groups, followed by pairwise Wilcoxon rank tests with Bonferroni correction. The Wilcoxon rank test was used to analyze the effect of thermomechanical aging in each adhesive system-cement or heat-press group (α=.05 for all tests). RESULTS: None of the specimens failed during cyclic loading. According to the Kruskal-Wallis test, the effect of the PEEK-Ti base bonding technique on the retention force in the nonaged (P=.019) and thermomechanically aged groups was significant (P=.010). In the nonaged groups, the heat-pressing technique resulted in a higher retention force than when the specimens were bonded by using the Monobond-Multilink hybrid combination (P=.031). Thermomechanical aging did not significantly affect the results (P>.241). All failures were adhesive, with cement remaining only on the Ti-bases. CONCLUSIONS: All bonding protocols tested resulted in a stable bond between PEEK and Ti-bases, as all specimens survived thermomechanical aging. The heat-pressing technique resulted in mean bond strength values similar to those obtained with the tested adhesive system-cement combinations with 1 exception; the nonaged heat-pressed groups presented higher bond strength than the Monobond-Multilink hybrid combination. Failure types indicated that the weaker bond was between the PEEK and the cements tested rather than between the titanium base and the cements, regardless of the adhesive system-cement combination.

Influence of 3D analysis software on measured deviations of CAD-CAM resin crowns from virtual design file: An in-vitro study.

OBJECTIVES: To evaluate a nonmetrology-grade and a metrology-grade 3D analysis software when measuring the deviations of computer-aided-design/ computer-aided-manufacturing (CAD-CAM) fabricated crowns from the virtual design file. MATERIALS AND METHODS: A right first molar on a mandibular dentate model was prepared and scanned with an intraoral scanner, i500 (Medit). A complete coverage crown was designed in standard tessellation language (STL) format and 20 resin crowns were fabricated with CAD-CAM. The crowns were then digitized using the same intraoral scanner (test-scans). Root mean square (RMS) method was used to evaluate the deviations between the test-scans and the design file of the crowns on 3 surfaces (overall, external, and internal) using a metrology-grade, Geomagic Control X (3D Systems) and a nonmetrology-grade, Medit Link (Medit) software. The data were analyzed with Welch two-sample t-tests to compare two software for the non-inferiority of the nonmetrology-grade software with a 50 µm threshold and the potential superiority of the metrology-grade software (α = 0.05). RESULTS: The Welch two-sample t-tests for the non-inferiority analysis showed that the differences between the nonmetrology-grade and the metrology-grade software were below the threshold of 50 µm for each surface tested (p <0.001). The differences between the two-tested software were nonsignificant for each surface analyzed when superiority was considered (p ≥.194). CONCLUSION: The nonmetrology-grade software performed similar to the metrology-grade software when analyzing the deviations of CAD-CAM crowns. Therefore, the nonmetrology-grade 3D analysis software may be considered for the deviation measurements of similar restorations. CLINICAL SIGNIFICANCE: The trueness of crowns after fabrication may affect their fit, and 3D analysis of trueness prior to the delivery appointment with the tested nonmetrology-grade software after fabrication may facilitate potential clinical adjustments and delivery of the crowns.