Pub Date : 2025-02-01DOI: 10.1016/j.prosdent.2023.03.012
Prem R. Thapar BDS , Jyoti B. Nadgere BDS, MDS , Janani Iyer BDS, MDS , Neelam A. Salvi BDS
Statement of problem
Diagnosing temporomandibular disorders without an adjunctive chairside diagnostic tool has made the management of temporomandibular disorders challenging and subjective. The use of magnetic resonance imaging, considered the standard imaging modality, is hindered because of high cost, a long learning curve, availability, and a longer examination time.
Purpose
The purpose of this systematic review and meta-analysis was to determine whether ultrasonography could be a chairside tool to help clinicians diagnose disc displacement in temporomandibular disorders.
Material and methods
An electronic search was conducted of the PubMed (including MEDLINE) and Cochrane Central database and the Google Scholar search engine for articles published from January 2000 to July 2020. Studies were chosen based on the inclusion criteria, which included the diagnostic technique's sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) with respect to imaging the displacement of the articular disc. The quality assessment of diagnostic accuracy studies (QUADAS- 2) tool was applied to assess the risk of bias for the included studies. The Meta-Disc 1.4 and RevMan 5.3 software program were used to conduct the meta-analysis.
Results
Seventeen articles were included in this systematic review, and a meta-analysis of 14 articles was done after applying the inclusion and exclusion criteria. None of the included articles were considered to have applicability concerns; however, 2 articles had a high risk of bias. The sensitivities and specificities for the different selected studies vary substantially from 21% to 95% with a good pooled sensitivity estimate of 71% while the specificities varied from 15% to 96% with a good pooled specificity estimate of 76%.
Conclusions
This systematic review and meta-analysis suggested that ultrasonography may have clinically acceptable diagnostic accuracy in diagnosing disc displacement of the temporomandibular joint, allowing the treatment of patients with temporomandibular disorders with greater assurance and success. Additional training in the operation and interpretation of ultrasonography is required to reduce the learning curve and make the use of ultrasonography relevant, straightforward, and routine in dentistry to supplement clinical examination and diagnosis in patients with suspected disc displacement of the temporomandibular joint. The evidence acquired needs to be standardized, and further research is required to provide stronger evidence.
{"title":"Diagnostic accuracy of ultrasonography compared with magnetic resonance imaging in diagnosing disc displacement of the temporomandibular joint: A systematic review and meta-analysis","authors":"Prem R. Thapar BDS , Jyoti B. Nadgere BDS, MDS , Janani Iyer BDS, MDS , Neelam A. Salvi BDS","doi":"10.1016/j.prosdent.2023.03.012","DOIUrl":"10.1016/j.prosdent.2023.03.012","url":null,"abstract":"<div><h3>Statement of problem</h3><div>Diagnosing temporomandibular disorders without an adjunctive chairside diagnostic tool has made the management of temporomandibular disorders challenging and subjective. The use of magnetic resonance imaging, considered the standard imaging modality, is hindered because of high cost, a long learning curve, availability, and a longer examination time.</div></div><div><h3>Purpose</h3><div><span>The purpose of this systematic review and meta-analysis was to determine whether </span>ultrasonography could be a chairside tool to help clinicians diagnose disc displacement in temporomandibular disorders.</div></div><div><h3>Material and methods</h3><div>An electronic search was conducted of the PubMed (including MEDLINE) and Cochrane Central database and the Google Scholar search engine for articles published from January 2000 to July 2020. Studies were chosen based on the inclusion criteria, which included the diagnostic technique's sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) with respect to imaging the displacement of the articular disc. The quality assessment of diagnostic accuracy studies (QUADAS- 2) tool was applied to assess the risk of bias for the included studies. The Meta-Disc 1.4 and RevMan 5.3 software program were used to conduct the meta-analysis.</div></div><div><h3>Results</h3><div>Seventeen articles were included in this systematic review, and a meta-analysis of 14 articles was done after applying the inclusion and exclusion criteria. None of the included articles were considered to have applicability concerns; however, 2 articles had a high risk of bias. The sensitivities and specificities for the different selected studies vary substantially from 21% to 95% with a good pooled sensitivity estimate of 71% while the specificities varied from 15% to 96% with a good pooled specificity estimate of 76%.</div></div><div><h3>Conclusions</h3><div>This systematic review and meta-analysis suggested that ultrasonography<span> may have clinically acceptable diagnostic accuracy in diagnosing disc displacement of the temporomandibular joint<span><span>, allowing the treatment of patients with temporomandibular disorders with greater assurance and success. Additional training in the operation and interpretation of ultrasonography is required to reduce the learning curve and make the use of ultrasonography relevant, straightforward, and routine in dentistry to supplement clinical examination and diagnosis in patients with suspected disc displacement of the </span>temporomandibular joint. The evidence acquired needs to be standardized, and further research is required to provide stronger evidence.</span></span></div></div>","PeriodicalId":16866,"journal":{"name":"Journal of Prosthetic Dentistry","volume":"133 2","pages":"Pages 446-454"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9772787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.prosdent.2023.04.012
Marta Revilla-León DDS, MSD, PhD , Elisabeth Fry , Achara Supaphakorn , Abdul B. Barmak MD, MSc, EdD , John C. Kois DDS, MSD
Statement of problem
Stereolithography (SLA) procedures can be chosen for manufacturing definitive crowns; however, how the print orientation impacts the trueness and precision of the intaglio surface of the printed definitive restorations is unclear.
Purpose
The purpose of this in vitro investigation was to calculate the manufacturing accuracy of the intaglio surface of SLA definitive resin-ceramic crowns fabricated at varying print orientations (0, 45, 75, or 90 degrees).
Material and methods
The standard tessellation language (STL) file of an anatomic contour molar crown was obtained and used to fabricate all the crowns by using a definitive resin-ceramic material (Permanent Crown) and an SLA printer (Form 3B+). Four groups were developed depending on the print orientation selected to manufacture the crowns: 0-, 45-, 70-, and 90-degree print orientation (n=30). Each crown specimen was digitized without the use of scanning powder by using a desktop scanner (T710). The crown design file was determined as the reference (control) group and used to calculate the fabricating trueness and precision of the intaglio surface of the specimens using the root mean square (RMS) error computation. Trueness data were examined by using 1-way ANOVA and post hoc pairwise multiple comparison Tukey tests, while precision data were analyzed using the Levene test (α=.05).
Results
The mean ±standard deviation RMS error discrepancies ranged from 37 ±3 μm to 113 ±11 μm. One-way ANOVA exposed significant trueness (P<.001) differences among the groups considered in this study. Furthermore, all the print orientation groups tested were different from each other (P<.001). The 0-degree group presented the best trueness value (37 μm), while the 90-degree group obtained the worst trueness value (113 μm). The Levene test exposed significant precision differences among the groups assessed (P<.001). The 0-degree group had a significantly lower standard deviation (higher precision) (3 μm) than the other groups, with no difference among the other groups tested (P>.05).
Conclusions
The fabricating trueness and precision of the intaglio surface of the SLA resin-ceramic crowns was impacted by the varying print orientations assessed.
{"title":"Manufacturing accuracy of the intaglio surface of definitive resin-ceramic crowns fabricated at different print orientations by using a stereolithography printer","authors":"Marta Revilla-León DDS, MSD, PhD , Elisabeth Fry , Achara Supaphakorn , Abdul B. Barmak MD, MSc, EdD , John C. Kois DDS, MSD","doi":"10.1016/j.prosdent.2023.04.012","DOIUrl":"10.1016/j.prosdent.2023.04.012","url":null,"abstract":"<div><h3>Statement of problem</h3><div>Stereolithography (SLA) procedures can be chosen for manufacturing definitive crowns; however, how the print orientation impacts the trueness and precision of the intaglio surface of the printed definitive restorations is unclear.</div></div><div><h3>Purpose</h3><div>The purpose of this in vitro investigation was to calculate the manufacturing accuracy of the intaglio surface of SLA definitive resin-ceramic crowns fabricated at varying print orientations (0, 45, 75, or 90 degrees).</div></div><div><h3>Material and methods</h3><div>The standard tessellation language (STL) file of an anatomic contour molar crown was obtained and used to fabricate all the crowns by using a definitive resin-ceramic material (Permanent Crown) and an SLA printer (Form 3B+). Four groups were developed depending on the print orientation selected to manufacture the crowns: 0-, 45-, 70-, and 90-degree print orientation (n=30). Each crown specimen was digitized without the use of scanning powder by using a desktop scanner (T710). The crown design file was determined as the reference (control) group and used to calculate the fabricating trueness and precision of the intaglio surface of the specimens using the root mean square (RMS) error computation. Trueness data were examined by using 1-way ANOVA and post hoc pairwise multiple comparison Tukey tests, while precision data were analyzed using the Levene test (α=.05).</div></div><div><h3>Results</h3><div>The mean ±standard deviation RMS error discrepancies ranged from 37 ±3 μm to 113 ±11 μm. One-way ANOVA exposed significant trueness (<em>P</em><.001) differences among the groups considered in this study. Furthermore, all the print orientation groups tested were different from each other (<em>P</em><.001). The 0-degree group presented the best trueness value (37 μm), while the 90-degree group obtained the worst trueness value (113 μm). The Levene test exposed significant precision differences among the groups assessed (<em>P</em><.001). The 0-degree group had a significantly lower standard deviation (higher precision) (3 μm) than the other groups, with no difference among the other groups tested (<em>P</em>>.05).</div></div><div><h3>Conclusions</h3><div>The fabricating trueness and precision of the intaglio surface of the SLA resin-ceramic crowns was impacted by the varying print orientations assessed.</div></div>","PeriodicalId":16866,"journal":{"name":"Journal of Prosthetic Dentistry","volume":"133 2","pages":"Pages 505-511"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9888053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.prosdent.2023.04.020
Sagar P. Jadeja BDS , Rupert S. Austin BDS, PhD, FDS, RCS, MClin Dent M Prostho , David W. Bartlett BDS, PhD, FDS, RCS, MRD
Statement of problem
Whether polyvinyl siloxane impressions are capable of reproducing 5-μm changes on natural freeform enamel and potentially enabling clinical measurements of early surface changes consistent with wear of teeth or materials is unclear.
Purpose
The purpose of this in vitro study was to investigate and compare polyvinyl siloxane replicas with direct measurements of sub-5-μm lesions on unpolished human enamel lesions by using profilometry, superimposition, and a surface subtraction software program.
Material and methods
Twenty ethically approved unpolished human enamel specimens were randomized to a previously reported cyclic erosion (n=10) and erosion and abrasion (n=10) model to create discrete sub-5-μm lesions on the surface. Low viscosity polyvinyl siloxane impressions were made of each specimen before and after each cycle and scanned by using noncontacting laser profilometry and viewed with a digital microscopy and compared with direct scanning of the enamel surface. The digital maps were then interrogated with surface- registration and subtraction workflows to extrapolate enamel loss from the unpolished surfaces by using step-height and digital surface microscopy to measure roughness.
Results
Direct measurement revealed chemical loss of enamel at 3.4 ±0.43 μm, and the polyvinyl siloxane replicas were 3.20 ±0.42 μm, respectively. For chemical and mechanical loss direct measurement was 6.12 ±1.05 μm and 5.79 ±1.06 μm for the polyvinyl siloxane replica (P=.211). The overall accuracy between direct and polyvinyl siloxane replica measurements was 0.13 +0.57 and −0.31 μm for erosion and 0.12 +0.99 and −0.75 μm for erosion and abrasion. Surface roughness and visualization with digital microscopy provided confirmatory data.
Conclusions
Polyvinyl siloxane replica impressions from unpolished human enamel were accurate and precise at the sub-5-μm level.
{"title":"Use of polyvinyl siloxane impressions to monitor sub-5-μm erosive tooth wear on unpolished enamel","authors":"Sagar P. Jadeja BDS , Rupert S. Austin BDS, PhD, FDS, RCS, MClin Dent M Prostho , David W. Bartlett BDS, PhD, FDS, RCS, MRD","doi":"10.1016/j.prosdent.2023.04.020","DOIUrl":"10.1016/j.prosdent.2023.04.020","url":null,"abstract":"<div><h3>Statement of problem</h3><div>Whether polyvinyl siloxane impressions are capable of reproducing 5-μm changes on natural freeform enamel and potentially enabling clinical measurements of early surface changes consistent with wear of teeth or materials is unclear.</div></div><div><h3>Purpose</h3><div>The purpose of this in vitro study was to investigate and compare polyvinyl siloxane replicas with direct measurements of sub-5-μm lesions on unpolished human enamel lesions by using profilometry, superimposition, and a surface subtraction software program.</div></div><div><h3>Material and methods</h3><div>Twenty ethically approved unpolished human enamel specimens were randomized to a previously reported cyclic erosion (n=10) and erosion and abrasion (n=10) model to create discrete sub-5-μm lesions on the surface. Low viscosity polyvinyl siloxane impressions were made of each specimen before and after each cycle and scanned by using noncontacting laser profilometry and viewed with a digital microscopy and compared with direct scanning of the enamel surface. The digital maps were then interrogated with surface- registration and subtraction workflows to extrapolate enamel loss from the unpolished surfaces by using step-height and digital surface microscopy to measure roughness.</div></div><div><h3>Results</h3><div>Direct measurement revealed chemical loss of enamel at 3.4 ±0.43 μm, and the polyvinyl siloxane replicas were 3.20 ±0.42 μm, respectively. For chemical and mechanical loss direct measurement was 6.12 ±1.05 μm and 5.79 ±1.06 μm for the polyvinyl siloxane replica (<em>P</em>=.211). The overall accuracy between direct and polyvinyl siloxane replica measurements was 0.13 +0.57 and −0.31 μm for erosion and 0.12 +0.99 and −0.75 μm for erosion and abrasion. Surface roughness and visualization with digital microscopy provided confirmatory data.</div></div><div><h3>Conclusions</h3><div>Polyvinyl siloxane replica impressions from unpolished human enamel were accurate and precise at the sub-5-μm level.</div></div>","PeriodicalId":16866,"journal":{"name":"Journal of Prosthetic Dentistry","volume":"133 2","pages":"Pages 577-583"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9564313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.prosdent.2024.02.028
Neena L. D’Souza BDS, MDS, Dip. Prostho, FRCDC, GCSRT (Harvard) , Emma ML Jutlah , Rachel A. Deshpande , Eszter Somogyi-Ganss DMD, MSc Pros, PhD, FRCDC, FAAMP
<div><h3>Statement of problem</h3><div>Evidence comparing the survival of zirconia crowns with metal-ceramic crowns is sparse. Knowledge of their survival and a comparison of their clinical outcomes would improve clinical decision making.</div></div><div><h3>Purpose</h3><div>The purpose of this university-based study was to compare the survival, failures, biological and technical complications encountered with zirconia and metal-ceramic crowns restored and followed up over a similar period.</div></div><div><h3>Material and methods</h3><div>This retrospective chart review consisted of 403 patients treated at the University of Toronto, Faculty of Dentistry, predoctoral dental clinic in whom zirconia (n=209) and metal-ceramic (n=306) crowns were inserted between September 2015 and July 2016 and followed for up to 7 years. Outcome measures included failure, causes for failure, and complications associated with survival. Inferential statistical analysis included the chi-squared test, <em>t</em> test, Mann-Whitney test, Bonferroni-adjusted z-test, Kaplan-Meier survival test, and logistic regression to examine differences between crown types and explore crown failures (α=.05).</div></div><div><h3>Results</h3><div>The mean follow-up period was 3.00 years (median 2.58 years). Forty-one (8.0%) crowns had no follow-up, with no difference in follow-up between crown type: metal-ceramic n=23(7.5%), zirconia n=18(8.6%), χ²(1)=0.20, <em>P</em>=.652). Excluding those with no follow-up, the follow-up time between metal-ceramic (mean=3.07, median=2.58) and zirconia (mean=3.54, median=3.32) crowns was statistically similar (<em>P</em>=.052). There were 62 anterior crowns (12.0%) and 453 posterior crowns (88.0%), χ²(1)=22.40, <em>P</em><.001, with no difference between groups. Overall, 44 crowns (8.5%) failed, 30 (9.8%) metal-ceramic and 14 (6.7%) zirconia, with no statistical difference in proportion of failed crowns between groups (χ²(1)=1.53, <em>P</em>=.216). There were 35 crowns with biological failures (6.8%), 26 (8.5%) in the metal-ceramic and 9 (4.4%) in the zirconia group, with no statistical difference between groups (χ²(1)=3.33, <em>P</em>=.068). Nine crowns had technical failures (1.7%), 4 (1.4%) in the metal-ceramic group and 5 (2.5%) in the zirconia group, with no statistical difference between groups (χ²(1)=0.73, <em>P</em>=.394). Biological (79.5%) rather than technical complications were found to be the most frequent cause of failure, goodness-of-fit χ²(1)=15.36, <em>P</em><.001. Tooth fracture (50.0%) specifically was found to be the most frequent cause of failure, χ²(3)=21.27, <em>P</em><.001. The total number of crowns that survived was 471 (91.5%); 276 (90.1%) were metal-ceramic and 195(93.3%) zirconia. The survival time (years) for metal-ceramic was mean=6.26, 95% CI [6.01–6.51] and for zirconia crowns mean=6.54, 95% CI [6.31–6.77]. Of the crowns that survived, 370 (78.6%) had no clinical complications, and 101 (21.4%) crowns demonstrat
{"title":"Comparison of clinical outcomes between single metal-ceramic and zirconia crowns","authors":"Neena L. D’Souza BDS, MDS, Dip. Prostho, FRCDC, GCSRT (Harvard) , Emma ML Jutlah , Rachel A. Deshpande , Eszter Somogyi-Ganss DMD, MSc Pros, PhD, FRCDC, FAAMP","doi":"10.1016/j.prosdent.2024.02.028","DOIUrl":"10.1016/j.prosdent.2024.02.028","url":null,"abstract":"<div><h3>Statement of problem</h3><div>Evidence comparing the survival of zirconia crowns with metal-ceramic crowns is sparse. Knowledge of their survival and a comparison of their clinical outcomes would improve clinical decision making.</div></div><div><h3>Purpose</h3><div>The purpose of this university-based study was to compare the survival, failures, biological and technical complications encountered with zirconia and metal-ceramic crowns restored and followed up over a similar period.</div></div><div><h3>Material and methods</h3><div>This retrospective chart review consisted of 403 patients treated at the University of Toronto, Faculty of Dentistry, predoctoral dental clinic in whom zirconia (n=209) and metal-ceramic (n=306) crowns were inserted between September 2015 and July 2016 and followed for up to 7 years. Outcome measures included failure, causes for failure, and complications associated with survival. Inferential statistical analysis included the chi-squared test, <em>t</em> test, Mann-Whitney test, Bonferroni-adjusted z-test, Kaplan-Meier survival test, and logistic regression to examine differences between crown types and explore crown failures (α=.05).</div></div><div><h3>Results</h3><div>The mean follow-up period was 3.00 years (median 2.58 years). Forty-one (8.0%) crowns had no follow-up, with no difference in follow-up between crown type: metal-ceramic n=23(7.5%), zirconia n=18(8.6%), χ²(1)=0.20, <em>P</em>=.652). Excluding those with no follow-up, the follow-up time between metal-ceramic (mean=3.07, median=2.58) and zirconia (mean=3.54, median=3.32) crowns was statistically similar (<em>P</em>=.052). There were 62 anterior crowns (12.0%) and 453 posterior crowns (88.0%), χ²(1)=22.40, <em>P</em><.001, with no difference between groups. Overall, 44 crowns (8.5%) failed, 30 (9.8%) metal-ceramic and 14 (6.7%) zirconia, with no statistical difference in proportion of failed crowns between groups (χ²(1)=1.53, <em>P</em>=.216). There were 35 crowns with biological failures (6.8%), 26 (8.5%) in the metal-ceramic and 9 (4.4%) in the zirconia group, with no statistical difference between groups (χ²(1)=3.33, <em>P</em>=.068). Nine crowns had technical failures (1.7%), 4 (1.4%) in the metal-ceramic group and 5 (2.5%) in the zirconia group, with no statistical difference between groups (χ²(1)=0.73, <em>P</em>=.394). Biological (79.5%) rather than technical complications were found to be the most frequent cause of failure, goodness-of-fit χ²(1)=15.36, <em>P</em><.001. Tooth fracture (50.0%) specifically was found to be the most frequent cause of failure, χ²(3)=21.27, <em>P</em><.001. The total number of crowns that survived was 471 (91.5%); 276 (90.1%) were metal-ceramic and 195(93.3%) zirconia. The survival time (years) for metal-ceramic was mean=6.26, 95% CI [6.01–6.51] and for zirconia crowns mean=6.54, 95% CI [6.31–6.77]. Of the crowns that survived, 370 (78.6%) had no clinical complications, and 101 (21.4%) crowns demonstrat","PeriodicalId":16866,"journal":{"name":"Journal of Prosthetic Dentistry","volume":"133 2","pages":"Pages 464-471"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140785104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.prosdent.2024.10.021
Nathaniel C. Lawson DMD, PhD , Pierpont Brown DMD , Suleiman Hamdan MCDT , Aaron Alford PhD , Amir H. Nejat DDS, MS
Statement of problem
Three-dimensional (3D) printing offers an efficient method of producing occlusal devices; however, their wear resistance is poorly understood.
Purpose
The purpose of this in vitro study was to compare the wear resistance of flexible and rigid 3D printed occlusal device materials with milled and conventionally processed occlusal device materials.
Material and methods
Blocks (n=8) of 3 flexible 3D printed materials (KeySplint Soft, NightGuard Flex 2, SmileGuard), 2 rigid 3D printed materials (KeySplint Hard, NightGuard Firm 2), 1 milled material (Ceramill A-Splint), 1 thermoform material (Erkoloc-Pro), 1 light-polymerized material (Eclipse Prosthetic Resin), 1 heat-polymerized material (Excel Formula Heat Cure Denture Base Material), and 1 autopolymerized material (Great Lakes Splint Resin Acrylic) were prepared and wet polished with 1200-grit SiC paper. The specimens were placed in a modified Alabama wear testing device with spherical zirconia antagonists. The devices applied a 20-N load and 2-mm horizontal slide for 400 000 cycles, and the test was run in a 33% glycerin solution. Following the wear test, the volumetric wear was measured with an optical profilometer. The Vickers microhardness of the materials was also measured (n=3). Volumetric wear and microhardness were compared with 1-way ANOVAs and Tukey post hoc analyses (α=.05).
Results
Significant differences were found between the wear of the different occlusal device materials (P<.001). The rigid 3D printed materials experienced similar wear as the light-polymerized, heat-polymerized, and milled occlusal device materials. The autopolymerized and thermoformed occlusal device material experienced significantly more wear (P<.05). The flexible 3D printed materials had the significantly greatest wear (P<.05). A statistically significant, strong negative correlation between hardness and volumetric wear was found (r=−.93; P<.001).
Conclusions
Rigid 3D printed occlusal device materials exhibit a high degree of wear resistance; however, flexible 3D printed occlusal device materials exhibit relatively low wear resistance.
{"title":"Wear resistance of 3D printed occlusal device materials","authors":"Nathaniel C. Lawson DMD, PhD , Pierpont Brown DMD , Suleiman Hamdan MCDT , Aaron Alford PhD , Amir H. Nejat DDS, MS","doi":"10.1016/j.prosdent.2024.10.021","DOIUrl":"10.1016/j.prosdent.2024.10.021","url":null,"abstract":"<div><h3>Statement of problem</h3><div>Three-dimensional (3D) printing offers an efficient method of producing occlusal devices; however, their wear resistance is poorly understood.</div></div><div><h3>Purpose</h3><div>The purpose of this in vitro study was to compare the wear resistance of flexible and rigid 3D printed occlusal device materials with milled and conventionally processed occlusal device materials.</div></div><div><h3>Material and methods</h3><div>Blocks (n=8) of 3 flexible 3D printed materials (KeySplint Soft, NightGuard Flex 2, SmileGuard), 2 rigid 3D printed materials (KeySplint Hard, NightGuard Firm 2), 1 milled material (Ceramill A-Splint), 1 thermoform material (Erkoloc-Pro), 1 light-polymerized material (Eclipse Prosthetic Resin), 1 heat-polymerized material (Excel Formula Heat Cure Denture Base Material), and 1 autopolymerized material (Great Lakes Splint Resin Acrylic) were prepared and wet polished with 1200-grit SiC paper. The specimens were placed in a modified Alabama wear testing device with spherical zirconia antagonists. The devices applied a 20-N load and 2-mm horizontal slide for 400 000 cycles, and the test was run in a 33% glycerin solution. Following the wear test, the volumetric wear was measured with an optical profilometer. The Vickers microhardness of the materials was also measured (n=3). Volumetric wear and microhardness were compared with 1-way ANOVAs and Tukey post hoc analyses (α=.05).</div></div><div><h3>Results</h3><div>Significant differences were found between the wear of the different occlusal device materials (<em>P</em><.001). The rigid 3D printed materials experienced similar wear as the light-polymerized, heat-polymerized, and milled occlusal device materials. The autopolymerized and thermoformed occlusal device material experienced significantly more wear (<em>P</em><.05). The flexible 3D printed materials had the significantly greatest wear (<em>P</em><.05). A statistically significant, strong negative correlation between hardness and volumetric wear was found (r=−.93; <em>P</em><.001).</div></div><div><h3>Conclusions</h3><div>Rigid 3D printed occlusal device materials exhibit a high degree of wear resistance; however, flexible 3D printed occlusal device materials exhibit relatively low wear resistance.</div></div>","PeriodicalId":16866,"journal":{"name":"Journal of Prosthetic Dentistry","volume":"133 2","pages":"Pages 576.e1-576.e6"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142622755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.prosdent.2024.11.003
Min Jeong DDS, MS, David H. Kwon DMD, MS, Sang J. Lee DMD, MMSc
{"title":"Response to the Letter to the Editor regarding, “Computer guided root tip extraction and implant placement: A clinical report”","authors":"Min Jeong DDS, MS, David H. Kwon DMD, MS, Sang J. Lee DMD, MMSc","doi":"10.1016/j.prosdent.2024.11.003","DOIUrl":"10.1016/j.prosdent.2024.11.003","url":null,"abstract":"","PeriodicalId":16866,"journal":{"name":"Journal of Prosthetic Dentistry","volume":"133 2","pages":"Pages 621-622"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142750793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
<div><h3>Statement of problem</h3><div>Implant surgical guides manufactured using different fabrication methods have been commonly used for computer-guided implant placement. However, how fabrication methods and the number of supporting teeth influence accuracy and stability remains uncertain.</div></div><div><h3>Purpose</h3><div>The purpose of this in vitro study was to evaluate the influence of fabrication methods and number of supporting teeth on the surface accuracy and dimensional stability of implant surgical guides with 3 different 3-dimensional (3D) printers and 1 computer numeric controlled (CNC) milling machine.</div></div><div><h3>Material and methods</h3><div>Two tooth-supported maxillary implant surgical guides with different number of supporting teeth (S: short span with 4 supporting teeth, L: long span with complete arch supporting) were used to fabricate the specimens. Eighty surgical guides were fabricated from 3 different 3D printers and 1 milling machine as follows: group SLA-S (n=10) and SLA-L (n=10) were fabricated with a desktop stereolithography (SLA) 3D printer and photopolymerizing resin; group PolyJet-S (n=10) and PolyJet-L (n=10) were fabricated with a PolyJet 3D printer and photopolymerizing resins; group DLP-S (n=10) and DLP-L (n=10) were fabricated with a desktop digital light processing (DLP) 3D printer and photopolymerizing resin; and group MILL-S (n=10) and group MILL-L (n=10) were fabricated with a 5-axis milling machine and polymethyl methacrylate (PMMA) blanks. All surgical guides were digitized immediately after postprocessing and after 1, 2, and 3 months using a desktop scanner. The congruency between design files and digitized files was quantified with the root mean square (RMS) error with a metrology program (Geomagic Control X). Two-way ANOVA was used to analyze trueness, and the Levene test was used to assess precision (α=.05).</div></div><div><h3>Results</h3><div>The fabrication methods and number of supporting teeth significantly affected the surface trueness of the guide (<em>P</em><.001). Milled guides had the lowest mean RMS value for surface trueness, 45 µm for guides with 4 supporting teeth and 59 µm for guides with complete arch supporting. Regarding precision, the Levene test revealed significant difference among fabrication methods (<em>P</em><.05), while no significant difference was found in the same fabrication method group (<em>P</em>>.05). After 3 months of storage, RMS values increased significantly in the complete arch supporting group comparison of SLA, PolyJet, and DLP (<em>P</em><.001, <em>P</em><.001, and <em>P</em>=.015, respectively). RMS values remained similar in other groups.</div></div><div><h3>Conclusions</h3><div>The trueness and dimensional stability of the surface of the implant surgical guides were affected by fabrication methods and the number of supporting teeth. However, the precision was only affected by fabrication methods. Milled surgical guides showed
{"title":"Effect of fabrication methods and number of supporting teeth on the surface accuracy and dimensional stability of implant surgical guides","authors":"Jiacheng Wu PhD , Yusen Shui MSc , Chenyang Xie PhD , Qin Wu PhD , Meiqi Yu MSc , Tian Luo PhD , Yuwei Zhao PhD , Haiyang Yu DDS, PhD","doi":"10.1016/j.prosdent.2024.10.031","DOIUrl":"10.1016/j.prosdent.2024.10.031","url":null,"abstract":"<div><h3>Statement of problem</h3><div>Implant surgical guides manufactured using different fabrication methods have been commonly used for computer-guided implant placement. However, how fabrication methods and the number of supporting teeth influence accuracy and stability remains uncertain.</div></div><div><h3>Purpose</h3><div>The purpose of this in vitro study was to evaluate the influence of fabrication methods and number of supporting teeth on the surface accuracy and dimensional stability of implant surgical guides with 3 different 3-dimensional (3D) printers and 1 computer numeric controlled (CNC) milling machine.</div></div><div><h3>Material and methods</h3><div>Two tooth-supported maxillary implant surgical guides with different number of supporting teeth (S: short span with 4 supporting teeth, L: long span with complete arch supporting) were used to fabricate the specimens. Eighty surgical guides were fabricated from 3 different 3D printers and 1 milling machine as follows: group SLA-S (n=10) and SLA-L (n=10) were fabricated with a desktop stereolithography (SLA) 3D printer and photopolymerizing resin; group PolyJet-S (n=10) and PolyJet-L (n=10) were fabricated with a PolyJet 3D printer and photopolymerizing resins; group DLP-S (n=10) and DLP-L (n=10) were fabricated with a desktop digital light processing (DLP) 3D printer and photopolymerizing resin; and group MILL-S (n=10) and group MILL-L (n=10) were fabricated with a 5-axis milling machine and polymethyl methacrylate (PMMA) blanks. All surgical guides were digitized immediately after postprocessing and after 1, 2, and 3 months using a desktop scanner. The congruency between design files and digitized files was quantified with the root mean square (RMS) error with a metrology program (Geomagic Control X). Two-way ANOVA was used to analyze trueness, and the Levene test was used to assess precision (α=.05).</div></div><div><h3>Results</h3><div>The fabrication methods and number of supporting teeth significantly affected the surface trueness of the guide (<em>P</em><.001). Milled guides had the lowest mean RMS value for surface trueness, 45 µm for guides with 4 supporting teeth and 59 µm for guides with complete arch supporting. Regarding precision, the Levene test revealed significant difference among fabrication methods (<em>P</em><.05), while no significant difference was found in the same fabrication method group (<em>P</em>>.05). After 3 months of storage, RMS values increased significantly in the complete arch supporting group comparison of SLA, PolyJet, and DLP (<em>P</em><.001, <em>P</em><.001, and <em>P</em>=.015, respectively). RMS values remained similar in other groups.</div></div><div><h3>Conclusions</h3><div>The trueness and dimensional stability of the surface of the implant surgical guides were affected by fabrication methods and the number of supporting teeth. However, the precision was only affected by fabrication methods. Milled surgical guides showed ","PeriodicalId":16866,"journal":{"name":"Journal of Prosthetic Dentistry","volume":"133 2","pages":"Pages 530.e1-530.e9"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142643792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.prosdent.2024.10.028
Jiaer Guo MDS , Xiaolu Wang MS , Zhixin Liu MDS , Jianying Zhou PhD , Lin Wang PhD
Statement of problem
Prosthetic screw loosening is a common mechanical complication of implant-supported fixed dental prostheses. Although techniques for detecting screw loosening in single implant-supported fixed dental prostheses have been reported, studies on the screw stability for splinted implant-supported fixed dental prostheses are lacking.
Purpose
The purpose of this in vitro study was to determine whether acoustic resonance frequency analysis using a newly developed system could detect prosthetic screw loosening in splinted implant-supported fixed dental prostheses.
Material and methods
Maxillary and mandibular edentulous gypsum casts with screw-retained definitive fixed dental prostheses supported by 6 implants were used. A tapping simulation (0.2 N, 50 Hz) was directly applied to the buccal side of the tested screw, and a pickup device was used to collect the acoustic signals. The resonance peak frequencies of these signals were extracted by using time-frequency-domain analysis based on short-time Fourier transform. A 2-way mixed analysis of variance was performed to evaluate how jaw position and insertion torque affect resonance peak frequency. The Pearson correlation analysis was used to assess the relationship between the insertion torque and resonance peak frequency for each screw (α=.05).
Results
Deviation from the insertion torque resulted in significant changes in the resonance peak frequency within 6 to 9 kHz. Additionally, significant positive correlation between the insertion torques and resonance peak frequencies was observed for all screws (P<.05). This correlation was affected by the position of the screw within the prosthesis. Specifically, screw loosening in the posterior and anterior regions had a greater influence on the resonance peak frequency than that in the central region.
Conclusions
The acoustic resonance peak frequency shifted leftward as the screw preload torque decreased, indicating a significant correlation with screw stability. These results suggest that acoustic resonance frequency analysis can be used to detect the stability status of a single prosthetic screw in a splinted implant-supported fixed dental prosthesis conveniently and with high sensitivity.
{"title":"Acoustic resonance frequency analysis for evaluating prosthetic screw stability in splinted implant-supported fixed dental prostheses: An in vitro study","authors":"Jiaer Guo MDS , Xiaolu Wang MS , Zhixin Liu MDS , Jianying Zhou PhD , Lin Wang PhD","doi":"10.1016/j.prosdent.2024.10.028","DOIUrl":"10.1016/j.prosdent.2024.10.028","url":null,"abstract":"<div><h3>Statement of problem</h3><div>Prosthetic screw loosening is a common mechanical complication of implant-supported fixed dental prostheses. Although techniques for detecting screw loosening in single implant-supported fixed dental prostheses have been reported, studies on the screw stability for splinted implant-supported fixed dental prostheses are lacking.</div></div><div><h3>Purpose</h3><div>The purpose of this in vitro study was to determine whether acoustic resonance frequency analysis using a newly developed system could detect prosthetic screw loosening in splinted implant-supported fixed dental prostheses.</div></div><div><h3>Material and methods</h3><div>Maxillary and mandibular edentulous gypsum casts with screw-retained definitive fixed dental prostheses supported by 6 implants were used. A tapping simulation (0.2 N, 50 Hz) was directly applied to the buccal side of the tested screw, and a pickup device was used to collect the acoustic signals. The resonance peak frequencies of these signals were extracted by using time-frequency-domain analysis based on short-time Fourier transform. A 2-way mixed analysis of variance was performed to evaluate how jaw position and insertion torque affect resonance peak frequency. The Pearson correlation analysis was used to assess the relationship between the insertion torque and resonance peak frequency for each screw (α=.05).</div></div><div><h3>Results</h3><div>Deviation from the insertion torque resulted in significant changes in the resonance peak frequency within 6 to 9 kHz. Additionally, significant positive correlation between the insertion torques and resonance peak frequencies was observed for all screws (<em>P</em><.05). This correlation was affected by the position of the screw within the prosthesis. Specifically, screw loosening in the posterior and anterior regions had a greater influence on the resonance peak frequency than that in the central region.</div></div><div><h3>Conclusions</h3><div>The acoustic resonance peak frequency shifted leftward as the screw preload torque decreased, indicating a significant correlation with screw stability. These results suggest that acoustic resonance frequency analysis can be used to detect the stability status of a single prosthetic screw in a splinted implant-supported fixed dental prosthesis conveniently and with high sensitivity.</div></div>","PeriodicalId":16866,"journal":{"name":"Journal of Prosthetic Dentistry","volume":"133 2","pages":"Pages 542.e1-542.e9"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142643791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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