Journal of Prosthetic Dentistry最新文献

{"title":"Mechanical properties of 3D printed denture base polymers.","authors":"Andrea Coldea, Felicitas Mayinger, John Meinen, Moritz Hoffmann, Bogna Stawarczyk","doi":"10.1016/j.prosdent.2025.02.009","DOIUrl":"https://doi.org/10.1016/j.prosdent.2025.02.009","url":null,"abstract":"<p><strong>Statement of problem: </strong>Studies on the mechanical properties of 3-dimensionally (3D) printed denture base polymers with appropriate test methods are lacking.</p><p><strong>Purpose: </strong>The purpose of this in vitro study was to determine the flexural strength (σ_f), elastic modulus (E), fracture toughness (K_IC), work of fracture (ω_e), and Martens hardness (HM) of 3D printed denture base polymers and to compare them with an injection molded material.</p><p><strong>Material and methods: </strong>Three resins for additive (Lucitone Digital Print, LDP; Flexcera Base, FCB and an experimental material, EXP) and 1 for injection molding (IvoBase Hybrid, IBH) fabrication were analyzed. Standardized specimens were fabricated, polished, tempered, and thermal cycled (5 °C to 55 °C) before testing for σ_f, E, K_IC, ω_e, and HM. The results were explored by global analysis (α=.05). The Kolmogorov-Smirnov test was used to test for data distribution. Parametric and nonparametric tests followed by pairwise comparison were applied to test for differences between groups.</p><p><strong>Results: </strong>The σf, E, and HM of 3D printed polymers were significantly lower than those of the injection molded, both for the tempered and aged groups. The σf was lowest for FCB and highest for IBH in the tempered state. The K_IC and ω_e of the tempered EXP and IBH groups were lower compared with those of FCB and LDP. After aging, EXP, FCB, and IBH presented K_IC in the same range, but it was lower than for LDP. Compared with the printable polymers, the control group IBH was not affected by artificial aging.</p><p><strong>Conclusions: </strong>The σ_f, E, and HM of printable polymers were lower than those of the control group, and specimens did not fracture in bend testing. In contrast, K_IC and ω_e were the highest for a printable polymer. Therefore, tension tests should be considered when testing ductile materials.</p>","PeriodicalId":16866,"journal":{"name":"Journal of Prosthetic Dentistry","volume":" ","pages":""},"PeriodicalIF":4.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143537341","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}

{"title":"Virtual patient representation with silicone guide and a 3D scanner accessory for a user-friendly facial scanning workflow: A clinical report of smile design and ceramic veneers","authors":"Khaled Q. Al Hamad BDS, MSc ,&nbsp;Bashar A. Al Rashdan BDS, MS ,&nbsp;Fatma T. Al-Kaff BDS","doi":"10.1016/j.prosdent.2023.04.029","DOIUrl":"10.1016/j.prosdent.2023.04.029","url":null,"abstract":"<div><div>Digital smile design and ceramic veneers are described with virtual patient representation. The procedure included facial scanning with a 3D scanner accessory (Structure sensor pro; Occipital Inc) mounted on a tablet computer (iPad; Apple Inc) and an innovative chairside silicone guide to replace the intraoral scan body for a straightforward and user-friendly workflow.</div></div>","PeriodicalId":16866,"journal":{"name":"Journal of Prosthetic Dentistry","volume":"133 3","pages":"Pages 630-636"},"PeriodicalIF":4.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9622358","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}

{"title":"Use of digital technology in prosthesis fabrication for an elderly patient with a maxillectomy and severe trismus: A clinical report","authors":"Mai Murase DDS, PhD ,&nbsp;Nehasha Pradhan BDS ,&nbsp;Yuka I. Sumita DDS, PhD ,&nbsp;Noriyuki Wakabayashi DDS, PhD","doi":"10.1016/j.prosdent.2023.04.033","DOIUrl":"10.1016/j.prosdent.2023.04.033","url":null,"abstract":"<div><div><span><span>This clinical report describes a novel approach based on digital technology to fabricate a maxillofacial prosthesis for a 90-year-old woman with severe </span>trismus who had undergone </span>maxillectomy<span> on the right side. The approach was safe, rapid, and less burdensome on this elderly patient, and the storage and communication of intraoral and maxillofacial prosthesis data without temporal and spatial constraints was helpful. A combination of digital and analog technology provided a maxillofacial prosthesis that improved the quality of life of this elderly patient with head and neck cancer and severe trismus.</span></div></div>","PeriodicalId":16866,"journal":{"name":"Journal of Prosthetic Dentistry","volume":"133 3","pages":"Pages 915-919"},"PeriodicalIF":4.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9645034","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}

{"title":"Effectiveness and one-year whiteness stability of different in-office bleaching agents and alternative protocols","authors":"Bibiana Gabardo Perez Mariano da Rocha PhD ,&nbsp;Javier Ruiz-López PhD ,&nbsp;María M. Pérez PhD ,&nbsp;Bruna Gaidarji MSc ,&nbsp;Giovanna Teixeira Frasson DDS ,&nbsp;Letícia Brandão Durand PhD","doi":"10.1016/j.prosdent.2024.06.011","DOIUrl":"10.1016/j.prosdent.2024.06.011","url":null,"abstract":"<div><h3>Statement of problem</h3><div>In-office bleaching has been widely researched. However, few studies have evaluated alternative protocols for this procedure. Moreover, information on the long-term stability of in-office whitening is limited.</div></div><div><h3>Purpose</h3><div>The purpose of this in vitro study was to evaluate the effectiveness and 1-year stability of in-office bleaching with 35% hydrogen peroxide (35%HP) and 37% carbamide peroxide (37%CP) using traditional and alternative protocols.</div></div><div><h3>Material and methods</h3><div>Forty human third molars were stained with tea and allocated to groups (n=10). Traditional protocols consisted of 3 applications of 35%HP for 15 minutes and 1 application of 37%CP for 45 minutes. Alternative protocols consisted of 1 application of 35%HP for 45 minutes and 3 applications of 37%CP for 45 minutes. Protocols were applied for 3 weeks. CIELab color coordinates were measured at baseline and weekly during treatment and at 1-week, 6-month, and 1-year follow-ups. Effectiveness and stability of the bleaching treatments were interpreted using 50:50% perceptibility and acceptability thresholds. CIELab, chroma, hue angle, and whiteness index were analyzed using the Wilcoxon signed-rank test (α=.05).</div></div><div><h3>Results</h3><div>All protocols showed improvement in bleaching after the first week (<em>P</em>≤.005). All bleaching procedures presented excellent whitening outcomes. Alternative protocols showed a larger rebound effect after 1 year, indicating less stability. For the whiteness index, no differences between the completion of the treatments and 1-year follow-up was found for the bleaching treatments and protocols (<em>P</em>&gt;.05), except for the 37%CP alternative protocol (<em>P</em>=.005).</div></div><div><h3>Conclusions</h3><div>All tested protocols presented excellent effectiveness in bleaching. Traditional protocols exhibited a greater whiteness stability, while the alternative protocols showed a greater rebound effect after 1 year.</div></div>","PeriodicalId":16866,"journal":{"name":"Journal of Prosthetic Dentistry","volume":"133 3","pages":"Pages 857-864"},"PeriodicalIF":4.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141544961","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}

{"title":"An evaluation of quantitative percussion diagnostics for determining the probability of a microgap defect in restored and unrestored teeth: A prospective clinical study","authors":"Cherilyn G. Sheets DDS ,&nbsp;Dennis A. Quan PhD ,&nbsp;Jean C. Wu DDS ,&nbsp;James C. Earthman PhD","doi":"10.1016/j.prosdent.2023.04.016","DOIUrl":"10.1016/j.prosdent.2023.04.016","url":null,"abstract":"<div><h3>Statement of problem</h3><div>Current dental diagnostics are image based and cannot detect a structural microgap defect such as a crack in a tooth. Whether percussion diagnostics can effectively diagnose a microgap defect is unclear.</div></div><div><h3>Purpose</h3><div>The purpose of the present study was to determine from a large multicenter prospective clinical study whether quantitative percussion diagnostics (QPD) could detect structural damage in teeth and whether a probability of its presence could be provided.</div></div><div><h3>Material and methods</h3><div>A nonrandomized prospective and multicenter clinical validation study with 224 participants was performed in 5 centers with 6 independent investigators. The study used QPD and the normal fit error to determine whether a microgap defect was present in a natural tooth. Teams 1 and 2 were blinded. Team 1 tested teeth scheduled for restoration with QPD, and Team 2 disassembled the teeth aided by a clinical microscope, transillumination, and a penetrant dye. Microgap defects were documented in written and video formats. Controls were participants without damaged teeth. The percussion response from each tooth was stored on a computer and analyzed. A total of 243 teeth were tested to provide approximately 95% power to test the performance goal of 70%, based on an assumed population overall agreement of 80%.</div></div><div><h3>Results</h3><div>Regardless of the collection method, tooth geometry, restoration material used, or restoration type, the data on detecting a microgap defect in a tooth were accurate. The data also reflected good sensitivity and specificity consistent with previously published clinical studies. The combined study data showed an overall agreement of 87.5% with a 95% confidence interval (84.2 to 90.3), beyond the 70% predetermined performance goal. The combined study data determined whether it was possible to predict the probability of a microgap defect.</div></div><div><h3>Conclusions</h3><div>The results showed that the data on detecting microgap defects in a tooth site were consistently accurate and confirmed that QPD provided information to aid the clinician in treatment planning and early preventative treatment. QPD can also alert the clinician of probable diagnosed and undiagnosed structural problems via the use of a probability curve.</div></div>","PeriodicalId":16866,"journal":{"name":"Journal of Prosthetic Dentistry","volume":"133 3","pages":"Pages 756-763"},"PeriodicalIF":4.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9882149","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}

{"title":"Relationship between anterior occlusion, arch dimension, and mandibular movement during speech articulation: A three-dimensional analysis","authors":"Taseef Hasan Farook BDS, MScDent ,&nbsp;Lameesa Ramees MFin ,&nbsp;James Dudley BDS, DClinDent","doi":"10.1016/j.prosdent.2024.08.001","DOIUrl":"10.1016/j.prosdent.2024.08.001","url":null,"abstract":"<div><h3>Statement of problem</h3><div>Studies correlating occlusal morphology from 3-dimensional intraoral scans with both soft and hard tissue dynamic landmark tracking within the same participant population are lacking.</div></div><div><h3>Purpose</h3><div>The purpose of this clinical study was to use 3-dimensional intraoral scanning, computer-aided design, electrognathography, and artificial intelligence to investigate the relationships between anterior occlusion and arch parameters with hard and soft tissue displacements during speech production.</div></div><div><h3>Material and methods</h3><div>An artificial intelligence (AI) driven software program and electrognathography was used to record the phonetic activities in 62 participants for soft tissue (ST) and hard tissue (HT) displacement. Soft tissue displacement was quantified by the mean difference between subnasale and soft tissue pogonion peaks during phonetic expressions, and hard tissue displacement was directly measured with an electrognathograph. Intercanine and intermolar distances, arch perimeters, and horizontal and vertical overlap were measured from the intraoral scan data.</div></div><div><h3>Results</h3><div>ST and HT displacements were successfully estimated for fricative (ST=7.16 ±4.51 mm, HT=11.86 ±4.02 mm), sibilant (ST=5.11 ±3.49 mm, HT=8.24 ±3.31 mm), linguodental (ST=5.72 ±4.46 mm, HT=10.01 ±3.16 mm), and bilabial (ST=5.56 ±4.64 mm, HT=11.69 ±4.28 mm) phonetics. Vertical overlap correlated positively with hard tissue movement during all speech expressions except bilabial phonetics (ρ=.30 to.41, <em>P</em>&lt;.05). Maxillary and mandibular arch perimeters showed negative correlations with soft tissue displacement during linguodental and bilabial speech (ρ=−.25 to −.41, <em>P</em>&lt;.05) but were significantly correlated with hard tissue movement during all speech assessments (ρ=−.28 to −.44, <em>P</em>&lt;.05). Maxillary intermolar distances negatively correlated with hard tissue phonetic expressions (ρ=−.24 to −.30, <em>P</em>&lt;.05). Participant age positively correlated with soft tissue displacement during all speech patterns (ρ=.28 to.33, <em>P</em>&lt;.05) and with weight increase (ρ=.27, <em>P</em>=.033), and hard tissue displacement (ρ=.25, <em>P</em>=.048) during maximum mouth opening significantly correlated with linguodental phonetics.</div></div><div><h3>Conclusions</h3><div>Within the study population, vertical overlap, maxillary intermolar distance, and dental arch perimeters correlated significantly with mandibular displacement during phonetic expression.</div></div>","PeriodicalId":16866,"journal":{"name":"Journal of Prosthetic Dentistry","volume":"133 3","pages":"Pages 881-887"},"PeriodicalIF":4.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142145883","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}

{"title":"Mechanical and optical properties of additively manufactured denture base resin in different colors modified with antimicrobial substances: An in vitro study","authors":"Rafat Sasany DDS, PhD ,&nbsp;Faris Z. Jamjoom BDS, MS, DMSc, FRCD(C) ,&nbsp;Burak Yilmaz DDS, PhD","doi":"10.1016/j.prosdent.2024.12.018","DOIUrl":"10.1016/j.prosdent.2024.12.018","url":null,"abstract":"<div><h3>Statement of problem</h3><div>Acrylic denture base resins are subject to colonization by oral and nonoral bacteria, contributing to the onset of denture stomatitis. However, how the addition of antimicrobial substances affects the mechanical and optical properties of additively manufactured denture base resin remains unclear.</div></div><div><h3>Purpose</h3><div>The purpose of this in vitro study was to investigate the surface roughness, color stainability, and flexural strength of antimicrobial-modified, additively manufactured polymethyl methacrylate (PMMA) denture base resin in tooth and gingiva colors.</div></div><div><h3>Material and methods</h3><div>Three antibacterial agents, e-poly-L-lysine+ methacryloyloxyethyl phosphorylcholine (e-MP), silver nanoparticles (AG-P), quaternized ammonium monomer (QA-P) synthesized via the reaction of octyl bromide and DMAEMA, were separately incorporated into tooth- or gingiva-colored 3-dimensionally (3D) printable PMMA specimens, simulating an implant-supported overdenture base or the artificial teeth (n=80). Unaltered specimens served as controls. Autopolymerizing acrylic resin was used to attach titanium matrix housings to gingiva-colored specimens. All specimens underwent coffee thermal cycling (CTC) comprising 10 000 cycles between 5 °C and 55 °C, and their color coordinates were measured. Surface roughness, color change (ΔE00), and flexural strength were calculated before and after CTC. The results were analyzed and compared by using ANOVA and the Tukey post hoc test (α=.05).</div></div><div><h3>Results</h3><div>All antibacterial agent-incorporated specimens showed lower ΔE00 values than the control (<em>P</em>=.001), with eM-P exhibiting the least color change (<em>P</em>=.001). The control group had the highest post-CTC roughness (Ra) values (<em>P</em>&lt;.001), while all test groups demonstrated higher flexural strength than the control (<em>P</em>=.001). CTC had no significant effect on flexural strength (<em>P</em>&gt;.115).</div></div><div><h3>Conclusions</h3><div>The addition of antimicrobial agents to 3D printable implant overdenture base resin in tooth and gingiva color affected the materials’ surface properties, color stainability, and flexural strength. Smoother surface, lower color stainability, and higher flexural strength were observed with the addition of eM-P.</div></div>","PeriodicalId":16866,"journal":{"name":"Journal of Prosthetic Dentistry","volume":"133 3","pages":"Pages 890.e1-890.e8"},"PeriodicalIF":4.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142950514","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}

{"title":"Gingival margin interfacial microleakage, staining, and push-out strengths of gingival colored composite resins in denture bases","authors":"Adriana Pinto Bezerra DDS, MSc ,&nbsp;Alexandra Feldmann DDS, MSc ,&nbsp;Luiz Carlos de Lima Dias Junior DDS, MSc, PhD ,&nbsp;Bruno Manoel Medeiros e Silva DDS ,&nbsp;Laura Costa Beber Copetti DDS ,&nbsp;Thais Marques Simek Vega Gonçalves DDS, MSc, PhD","doi":"10.1016/j.prosdent.2024.12.027","DOIUrl":"10.1016/j.prosdent.2024.12.027","url":null,"abstract":"<div><h3>Statement of problem</h3><div>Staining at the gingival margin could impact denture longevity, but the behavior of gingival colored composite resins (GCCs) in this area remains unclear.</div></div><div><h3>Purpose</h3><div>This in vitro study evaluated surface staining, microleakage, and push-out bond strength at the gingival margin of artificial teeth, comparing two consistencies of GCCs with two resin base materials.</div></div><div><h3>Material and methods</h3><div>Specimens included artificial teeth (Ivostar; Ivoclar AG) and two acrylic resin base materials: conventional (Ondacryl; Clássico) and high-impact (Diamond D; Keystone Industries) (n=300). Specimens were divided in three groups: control (acrylic resin) and experimental groups, receiving one of the two GCCs consistencies: paste (SR Nexco; Ivoclar AG) or flowable (Gradia Plus Gum; GC Europe)). Initial artificial aging treatment in distilled water (5 days at 55º C) was performed and the specimens were then immersed in 5% methylene blue dye or coffee for 7 days at 37º C. Staining was visually assessed, and the specimens were sectioned for dye infiltration analysis at the gingival margin using a stereomicroscope. Bond strength was measured with the push-out test in the gingival colored composite resin specimens. Data were analyzed using 2-way and 3-way ANOVA with Bonferroni post hoc test and Kruskal-Wallis test with Dunn post hoc test (α=.05).</div></div><div><h3>Results</h3><div>A significantly higher surface staining and microleakage was observed in experimental groups compared to the control (acrylic resin) (<em>P</em>&lt;.001). Surface staining revealed that paste consistency GCC was more susceptible to discoloration in coffee, while flowable GCC was more affected by methylene blue. Lower microleakage values were observed in the control (acrylic resin) groups (0.11 ±0.13 mm for the conventional base and 0.08 ±0.11 mm for the high-impact base) in comparison with the experimental groups (<em>P</em>&lt;.05). The flowable GCC showed the highest microleakage with methylene blue (0.98 ±0.21 mm for the conventional base and 0.91 ±0.31 mm for the high-impact base), significantly greater than the paste consistency for both base materials (0.53 ±0.22 mm for the conventional base and 0.66 ±0.34 mm for the high-impact base; <em>P</em>&lt;.001). For coffee immersion, both GCC consistencies displayed similar microleakage values (<em>P</em>&gt;.05). Push-out bond strength was comparable between paste and flowable GCCs (<em>P</em>&gt;.05).</div></div><div><h3>Conclusions</h3><div>Microleakage at the gingival margin was significantly greater when GCC was applied, regardless of the consistency. However, the GCC consistency seems to not affect push-out bond strength. Further clinical studies are needed to better understand the impact of these findings on prosthesis longevity.</div></div>","PeriodicalId":16866,"journal":{"name":"Journal of Prosthetic Dentistry","volume":"133 3","pages":"Pages 903.e1-903.e10"},"PeriodicalIF":4.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143028963","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}

{"title":"Proposal regarding horizontal and vertical positioning of single implants placed in healed sites: Effect on cervical crown form and the need for bone grafting","authors":"Joon W. Park DDS ,&nbsp;Charles J. Goodacre DDS, MSD ,&nbsp;Joseph Y.K. Kan DDS, MS ,&nbsp;Jaime Lozada DDS ,&nbsp;Aladdin Al-Ardah DDS, MS","doi":"10.1016/j.prosdent.2024.05.027","DOIUrl":"10.1016/j.prosdent.2024.05.027","url":null,"abstract":"<div><h3>Statement of problem</h3><div>When single implants are placed in healed sites, guidelines are lacking on the horizontal and vertical implant positions that optimize cervical crown form and the implant locations that would require bone grafting to develop the optimal crown form.</div></div><div><h3>Purpose</h3><div>The purpose of this clinical study was to evaluate the cervical contour of wax patterns formed on casts of single implants placed in healed sites and to determine which horizontal and vertical implant positions produced the best cervical crown form and which indicated the need for bone grafting.</div></div><div><h3>Material and methods</h3><div>Fifty-eight wax patterns were fabricated on casts where implants had been placed in healed sites without bone grafting. The wax patterns were subjectively assessed by 5 dental faculty members and 5 graduate students as having good, fair, or poor cervical crown form. Horizontal measurements were made between the facial surface of the implant and a round metal wire connecting the gingival zeniths of the adjacent teeth. Vertical measurements were also made between the wire and implant platform. The subjective assessments along with the horizontal and vertical implant position measurements were used to propose guidelines for optimal implant placement in healed sites.</div></div><div><h3>Results</h3><div>Horizontal distances of 2.0 to 3.0 mm produced good cervical crown contours, with distances &gt;3.0 mm and &lt;2.0 mm resulting in fair or poor assessments. Vertical distances of 3.0 to 4.0 mm were judged to have good cervical crown contour, whereas depths of 1.0 mm or less were assessed as poor.</div></div><div><h3>Conclusions</h3><div>Based on the subjective assessment of wax patterns formed on casts of single implants placed in healed sites, a guideline of 2.0 to 3.0 mm is proposed for the horizontal distance between a line connecting the adjacent gingival zeniths and the facial surface of the implant. A vertical distance guideline of 3.0 to 4.0 mm is proposed between the adjacent gingival zeniths and the implant platform.</div></div>","PeriodicalId":16866,"journal":{"name":"Journal of Prosthetic Dentistry","volume":"133 3","pages":"Pages 827-837"},"PeriodicalIF":4.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141450743","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}

{"title":"A two-year clinical trial of enamel wear opposing 5Y-TZP and lithium disilicate crowns","authors":"Piyarat Woraganjanaboon DDS, MSc ,&nbsp;Pisol Senawongse DDS, MSc, PhD ,&nbsp;Chuchai Anunmana DDS, MS, PhD","doi":"10.1016/j.prosdent.2024.07.009","DOIUrl":"10.1016/j.prosdent.2024.07.009","url":null,"abstract":"<div><h3>Statement of problem</h3><div>Clinical information on enamel wear opposing 5 mol% yttria-stabilized tetragonal zirconia polycrystal (5Y-TZP) or lithium disilicate crowns is lacking. Moreover, the effect of surface roughness on the wear of enamel antagonists remains unclear.</div></div><div><h3>Purpose</h3><div>The purpose of this clinical study was to quantify the vertical wear and total volume of wear while also measuring the surface roughness of antagonists at 6-month intervals over 2 years.</div></div><div><h3>Material and methods</h3><div>A tooth-supported first molar 5Y-TZP Lava Esthetic Fluorescent Zirconia crown or an IPS e.max CAD lithium disilicate crown was randomly provided for 24 participants (n=12). The contralateral first molar and opposite teeth were the natural enamel controls. The crowns were fabricated using computer-aided design and computer-aided manufacturing (CAD-CAM) technology and then polished. The data were gathered every 6 months at recall appointments with an intraoral scanner and a polyvinyl siloxane impression. A 3-dimensional (3D) comparative software program was used to measure the maximum vertical and volume loss on opposing enamel, as well as on the enamel control on the opposite side of the mouth. The surface of epoxy resin replicas was analyzed using a scanning electron microscope. The surface roughness of the cusp replica was measured with a 3D laser microscope. The crown's antagonist enamel and natural enamel wear were compared using a 2-way repeated measure ANOVA (α=.05).</div></div><div><h3>Results</h3><div>No significant difference was found in the average volume loss between the crown's antagonist enamel (ZTE 0.042 ±0.005 mm³, LTE 0.048 ±0.006 mm³) and the enamel control (ZCE 0.046 ±0.004 mm³, LCE 0.050 ±0.005 mm³) (<em>P</em>&gt;.05). No significant difference was found in surface roughness between the crown's antagonist enamel (antagonist enamel of zirconia group [ZTE] 0.7 ±0.3 µm, antagonist enamel of lithium disilicate group [LTE] 0.6 ±0.3 µm) and the enamel control (enamel control of zirconia group [ZCE] 0.7 ±0.3 µm, enamel control of lithium disilicate group [LCE] 0.5 ±0.2 µm) in both zirconia and lithium disilicate groups (<em>P</em>&gt;.05). Also, no correlation was found between the amount of wear and the roughness of the surface. The wear patterns observed on the opposing enamel surfaces of the monolithic zirconia and lithium disilicate materials were found to be similar to those seen on natural enamel.</div></div><div><h3>Conclusions</h3><div>A 2-year clinical investigation found that polished lithium disilicate and 5Y-TZP crowns did not affect enamel wear more than enamel against enamel, contrary to laboratory studies. Another finding revealed that surface roughness did not significantly affect wear.</div></div>","PeriodicalId":16866,"journal":{"name":"Journal of Prosthetic Dentistry","volume":"133 3","pages":"Pages 747-755"},"PeriodicalIF":4.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141975943","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}