The Journal of prosthetic dentistry最新文献

{"title":"Accelerated color change in a maxillofacial elastomer with and without pigmentation.","authors":"John J. Gary, E. F. Huget, Larry D. Powell","doi":"10.1067/MPR.2001.114683","DOIUrl":"https://doi.org/10.1067/MPR.2001.114683","url":null,"abstract":"STATEMENT OF PROBLEM\u0000Maxillofacial prostheses require frequent replacement because the elastomer and its color additives undergo changes.\u0000\u0000\u0000PURPOSE\u0000This study attempted to determine whether predictable color changes occur when 3 pigments are individually incorporated into a specific silicone elastomer.\u0000\u0000\u0000MATERIAL AND METHODS\u0000The materials included an RTV elastomer; 1 natural inorganic pigment, burnt sienna; and 2 synthetic organic pigments, Hansa yellow and alizarin red. Eight test groups of 10 polymerized specimens were established. Groups 1 and 2, acting as the control, involved only the elastomer. Groups 3 and 4 were composed of elastomer and burnt sienna. Groups 5 and 6 consisted of elastomer and Hansa yellow. Groups 7 and 8 comprised elastomer and alizarin red. Odd-numbered groups were assigned to a test site in Miami, Fla., whereas the even numbered groups went to Phoenix, Ariz. Specimens weathered in Miami and Phoenix received sunlight exposures of 1305.7 MJ/m2 and 1310.2 MJ/m2, respectively, over time. Before and after weathering, the L* a* b* color parameter (DeltaE*) of each specimen was determined spectrophotometrically.\u0000\u0000\u0000RESULTS\u0000Mean color changes that occurred in Arizona were larger than those produced in Florida. Specifically, these differences ranged from 0.4 (alizarin red groups) to 2.36 units for the 2 unpigmented control groups. Other differences showed significance for the unpigmented (P=.001), burnt sienna (P=.006), and Hansa yellow groups (P=.001).\u0000\u0000\u0000CONCLUSION\u0000Outdoor weathering tests in which documented ASTM methods were used provided a valid baseline for future research on color changes in maxillofacial prostheses.","PeriodicalId":185384,"journal":{"name":"The Journal of prosthetic dentistry","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123983962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In vitro color stability of double-layer veneers after accelerated aging.","authors":"G. Heydecke, F. Zhang, M. Razzoog","doi":"10.1067/MPR.2001.115385","DOIUrl":"https://doi.org/10.1067/MPR.2001.115385","url":null,"abstract":"STATEMENT OF PROBLEM\u0000Porcelain laminates made from thin alumina shells veneered with feldspathic porcelain could be a promising alternative to conventional veneers. Long-term shade stability is critical for esthetics.\u0000\u0000\u0000PURPOSE\u0000This study compared changes in CIE L*a*b* color coordinates of simulated veneers made from aluminum oxide core material veneered with feldspathic porcelain after 300 hours of accelerated photothermal aging (weathering).\u0000\u0000\u0000MATERIAL AND METHODS\u0000Fifteen aluminum oxide disks (Procera) were divided into 3 groups. Each of the 5 disks was veneered with All-Ceram porcelain of the Vita shades A1 and B4, respectively. Five disks remained unfinished as controls. The disks were bonded to composite substrates simulating stained teeth. The color of the specimens was measured with a colorimeter. All specimens were subjected to 300 hours of accelerated aging under light exposure and thermocycling. Color measurements were repeated, and the data were statistically evaluated with multiple paired t tests.\u0000\u0000\u0000RESULTS\u0000Color changes in the test groups involved an increase in lightness and a decrease in chroma. The calculated total color differences were not statistically significant compared with a level of 3 DeltaE units.\u0000\u0000\u0000CONCLUSION\u0000This simulation of double-layer veneers appears to demonstrate acceptable color stability for this type of restoration. Clinical research is necessary to substantiate these in vitro findings.","PeriodicalId":185384,"journal":{"name":"The Journal of prosthetic dentistry","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127465539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nondestructive, in vitro quantification of crown margins.","authors":"C. Mitchell, M. R. Pintado, W. Douglas","doi":"10.1067/MPR.2001.114268","DOIUrl":"https://doi.org/10.1067/MPR.2001.114268","url":null,"abstract":"STATEMENT OF PROBLEM\u0000It is important that artificial crowns fit the prepared tooth accurately, as marginal deficiencies are predisposed to plaque accumulation and lead to increased risk of periodontal disease. Various methods of evaluation for marginal fit are described in the literature, but most approaches are limited by destructive methods of assessment and/or small points of measurement.\u0000\u0000\u0000PURPOSE\u0000This study compared, in vitro, the marginal fit of 4 types of complete crowns on human premolar teeth with the use of nondestructive profilometry. This method determined whether fit was influenced by type of crown or surface morphology of the tooth, namely, grooved or ungrooved surfaces.\u0000\u0000\u0000MATERIAL AND METHODS\u0000Four groups of specimens were prepared for complete crowns: group BA, bonding alloy with chamfer finish line; group G, gold alloy with chamfer finish line; group PC, porcelain with a chamfer finish line; and group PS, porcelain with a shoulder finish line. Two profiles of grooved mesial and ungrooved distal surfaces of the teeth were performed: (1) teeth prepared for each type of crown and (2) teeth with crowns seated but not cemented. Marginal fit (absolute marginal discrepancy) from the finish line edge of the tooth preparations to crown edges (CE) and leading edges (LE) of crowns were measured.\u0000\u0000\u0000RESULTS\u0000A 2-way analysis of variance for crown type and tooth surface morphology revealed significant differences between crown types for all measurement parameters, except vertical LE. The effect of surface morphology was not significant, except for vertical LE (P<.05). For all parameters, except vertical LE, the ranking of marginal fit discrepancies from greatest to least was as follows: group PC, G, BA, and PS. For vertical LE distances, the ranking was PS, BA, G, and PC (P<.05).\u0000\u0000\u0000CONCLUSION\u0000Profilometry was used as a nondestructive, accurate method of evaluating the absolute marginal fit of different types of crowns. Marginal fits varied continuously around the circumference of each crown and made clinical assessment of fit accuracy subjective and arduous.","PeriodicalId":185384,"journal":{"name":"The Journal of prosthetic dentistry","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124578255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Maxillofacial prosthetic rehabilitation of a midfacial defect complicated by microstomia: a clinical report.","authors":"A. Cheng, Alvin G. Wee, L. Tat-Keung","doi":"10.1067/MPR.2001.115030","DOIUrl":"https://doi.org/10.1067/MPR.2001.115030","url":null,"abstract":"Severe limitation in the oral opening, though an uncommon clinical presentation, makes gaining access to the oral cavity difficult for any dental procedure. This article describes the maxillofacial prosthetic management of a patient with a midfacial defect complicated by postsurgical microstomia. Intraoral and extraoral prostheses restored the patient's speech, dental articulation, mastication, lip support, esthetics, and anterior oral seal.","PeriodicalId":185384,"journal":{"name":"The Journal of prosthetic dentistry","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116826894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Repair of denture base resin using woven metal and glass fiber: effect of methylene chloride pretreatment.","authors":"E. Nagai, K. Otani, Y. Satoh, S. Suzuki","doi":"10.1067/MPR.2001.115183","DOIUrl":"https://doi.org/10.1067/MPR.2001.115183","url":null,"abstract":"STATEMENT OF PROBLEM\u0000A durable repairing system for denture base fracture is desired to avoid recurrent fracture. Purpose. This study evaluated the strength and modulus of elasticity of repaired acrylic specimens reinforced with various processes.\u0000\u0000\u0000MATERIAL AND METHODS\u0000Transverse strength and modulus of elasticity of repaired acrylic denture base specimens were evaluated with a 3-point bending test and compared with a heat-polymerized control. Autopolymerizing acrylic resin was used with woven metal fiber and glass fiber with and without methylene chloride surface treatment (n = 6 per group). The specimens were cut in half and fixed in a metal mold to obtain a space for placing the repairing resin. A cavity was prepared when metal or glass fiber was used. All specimens were stored in 37 degrees C distilled water for 48 hours before the test. All data were statistically analyzed with 1-way ANOVA, and differences among groups were analyzed with Fisher test (P< or =.05).\u0000\u0000\u0000RESULTS\u0000The mean value of the transverse strength for the control was 87.2 MPa. The specimens repaired by glass fiber with methylene chloride surface treatment exhibited the highest transverse strength (96.8 MPa), which was significantly higher than that of the control (P< or =.05). The elastic modulus of the specimens repaired by glass fiber with methylene chloride surface treatment (4189.3 MPa) was significantly greater than that of the control (2683.7 MPa) at a 95% level of confidence. The values of transverse strength and elastic modulus were highest when the surface treatment was combined with a reinforcing glass fiber.\u0000\u0000\u0000CONCLUSION\u0000Reinforcement with glass fiber and methylene chloride pretreatment produced transverse strength and a modulus of elasticity higher than the control.","PeriodicalId":185384,"journal":{"name":"The Journal of prosthetic dentistry","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128399852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stress distribution around maxillary implants in anatomic photoelastic models of varying geometry. Part I.","authors":"M. Gross, J. Nissan, R. Samuel","doi":"10.1067/MPR.2001.115252","DOIUrl":"https://doi.org/10.1067/MPR.2001.115252","url":null,"abstract":"STATEMENT OF PROBLEM\u0000It is unclear which implant inclination and position are most favorable in relation to the supporting anatomy and loading direction in the maxilla.\u0000\u0000\u0000PURPOSE\u0000This study was designed to examine stress distribution around implants in a 2-dimensional photoelastic anatomic model.\u0000\u0000\u0000MATERIAL AND METHODS\u0000Two 2-dimensional photoelastic models were prepared with opposing 8-degree cylinder metal implant and molar teeth analogues. A frontal anatomic sectional plate model based on a CT section at the first molar was symmetrically loaded through its long axis. A midfacial rectangular model based on the same section was loaded in a different direction with varying supporting geometries.\u0000\u0000\u0000RESULTS\u0000Stress distribution around the maxillary implant was highest in the buccal concavity at the apical buccal third and in the lingual concavity on intercuspal loading. No stress concentration occurred at the implant apex under the sinus for axial and nonaxial loading in both anatomic model geometries. On lateral loading, stress concentration was observed at the buccal concavity and at the implant neck. In the midfacial block model, principal stresses were concentrated at the maxillary implant neck on nonaxial loading and at the apex on axial loading.\u0000\u0000\u0000CONCLUSION\u0000This 2-dimensional skull model showed different patterns of stress distribution among the maxillary implant, mandibular implant, and teeth. The highest principal stress concentration was seen at the buccal concavity of the maxillary implant; this may play a role in osseointegration with highly angled implants in the posterior maxilla. Differences in stress distribution between anatomic and nonanatomic models showed how the supporting geometry (for example, sinus/nasal anatomy), boundary conditions, and loading direction influence stress distribution.","PeriodicalId":185384,"journal":{"name":"The Journal of prosthetic dentistry","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126263760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fabrication of imaging and surgical guides for dental implants.","authors":"D. Almog, E. Torrado, S. Meitner","doi":"10.1067/MPR.2001.115388","DOIUrl":"https://doi.org/10.1067/MPR.2001.115388","url":null,"abstract":"Research and experience have suggested that the success of dental implants depends on a well-developed and careful treatment plan approach. Historically, implant size and angulation were determined with the use of panoramic radiographs and clinical judgment during surgery. This occasionally resulted in mechanical and esthetic compromise. This article describes the step-by-step fabrication process for 4 different imaging and surgical guides. Set-up disks, which enhance the design and fabrication of guides, also are introduced. These guides are used in conjunction with cross-sectional tomography during the preimplant assessment of surgical sites.","PeriodicalId":185384,"journal":{"name":"The Journal of prosthetic dentistry","volume":"82 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124780384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Curing potential of dual-polymerizable resin cements in simulated clinical situations.","authors":"W. Caughman, D. Chan, F. Rueggeberg","doi":"10.1067/MPR.2001.114842","DOIUrl":"https://doi.org/10.1067/MPR.2001.114842","url":null,"abstract":"STATEMENT OF PROBLEM\u0000Little is known about the ability of dual-polymerizable resin cements to polymerize when they are used in various clinical scenarios.\u0000\u0000\u0000PURPOSE\u0000This study was conducted to determine whether any of 6 commercially available dual-polymerizable resin cements should be classified as an \"all-purpose\" resin cement.\u0000\u0000\u0000MATERIAL AND METHODS\u0000. Chemical conversion values (C=C converted to C-C, or the extent of the curing reaction) of 6 commercially available dual-polymerizable resin cements were determined with infrared spectroscopy in 5 clinically relevant scenarios. Scenarios included: using each cement in a dual-polymerizable mode (mixing of 2 pastes); light polymerizing curing through Mylar sheets (dual-Mylar), which served as the control; light polymerizing through 3-mm porcelain (dual-3 mm); and no exposure to light (dual-no light). The single-component light-polymerizable product was also tested as follows: exposed directly through Mylar (light-Mylar) or exposed through 3 mm of porcelain (light-3 mm). Results. For each product, dual-Mylar treatment yielded the highest conversion value of all treatments (control for each product). For all products, dual-3 mm conversion was at least 97% of control and equivalent to control, with the exception of Lute-It!. Dual-no light conversion was less than control treatment but at least 86% of control for all products except for Variolink II (62% of control). For all products in dual-no light mode, except Choice and Variolink II, conversion was at least equal to the light-Mylar values. Only 1 product (Variolink II) did not demonstrate increased conversion values for dual-Mylar compared with light-Mylar treatments. For most other products (Calibra, Insure, and Lute-It!), conversion values for light-3 mm were significantly less than for light-Mylar. Conversion values for Nexus, Choice, and Variolink II were equivalent between light-Mylar and light-3 mm treatments.\u0000\u0000\u0000CONCLUSION\u0000The choice of a dual-polymerizable cement should be based on its intended use because not all products polymerize adequately in every clinical situation. Although no cement met the stated criteria for an \"all-purpose\" cement, those tested did produce a range of product-specific results.","PeriodicalId":185384,"journal":{"name":"The Journal of prosthetic dentistry","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128486109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The influence of intracrevicular crown margins on gingival health: preliminary findings.","authors":"S. Kancyper, S. Koka","doi":"10.1067/MPR.2001.115386","DOIUrl":"https://doi.org/10.1067/MPR.2001.115386","url":null,"abstract":"STATEMENT OF PROBLEM\u0000The effect on gingival tissue of various crown materials in combination with different abutment biomaterials should be investigated.\u0000\u0000\u0000PURPOSE\u0000This in vivo study determined the gingival health and subgingival levels of periodontal inflammation-associated bacteria adjacent to various crown and abutment material combinations.\u0000\u0000\u0000MATERIAL AND METHODS\u0000. Patients in the study received 1 of 5 treatments: an all-ceramic crown luted to a natural tooth, a metal-ceramic (titanium) crown luted to natural tooth, a metal-ceramic (high noble alloy) crown luted to natural tooth, an all-ceramic crown luted to a titanium implant abutment, or a metal-ceramic (high noble alloy) crown luted to a titanium implant abutment. Plaque was collected at least 6 months after luting by paper point from the gingival sulcus of each crown and an adjacent unrestored (control) tooth. DNA probe analysis was performed to determine the levels of Porphyromonas gingivalis, Prevotella intermedia, and Actinobacillus actinomycetemcomitans. In addition, plaque, gingival redness, swelling, and bleeding scores were recorded with use of the California Dental Association scale. Statistical analysis was used to determine the effect of restoration/abutment type on levels of the bacterial species and clinical parameters pertaining to gingival health.\u0000\u0000\u0000RESULTS\u0000None of the sulci sampled contained detectable levels of the 3 bacteria. Plaque levels and gingival redness, swelling, and bleeding scores were low. All treatment groups had similar soft tissue response as measured by gingival redness, swelling, and bleeding. Plaque scores from all-ceramic crown/implant abutment sites were higher than plaque scores from all-ceramic crown/natural tooth sites. However, differences between experimental and control sites within the same treatment group were not observed (P>.05) with any of the 4 clinical measures.\u0000\u0000\u0000CONCLUSION\u0000In patients with suitable oral hygiene, tooth-supported and implant-supported crowns with intracrevicular margins were not predisposed to unfavorable gingival and microbial responses.","PeriodicalId":185384,"journal":{"name":"The Journal of prosthetic dentistry","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126866493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of groove placement on the retention/resistance of resin-bonded retainers for maxillary and mandibular second molars.","authors":"R. Emara, D. Byrne, D. Hussey, N. Claffey","doi":"10.1067/MPR.2001.114512","DOIUrl":"https://doi.org/10.1067/MPR.2001.114512","url":null,"abstract":"STATEMENT OF PROBLEM\u0000Lack of retention/resistance form in the clinical preparation of teeth for resin-bonded retainers may lead to clinical failure.\u0000\u0000\u0000PURPOSE\u0000This study investigated the effect of proximal grooves on the retention/resistance of cast resin-bonded retainers for maxillary and mandibular second molar teeth.\u0000\u0000\u0000MATERIAL AND METHODS\u0000Two ivorine teeth (a maxillary and a mandibular second molar) were prepared for resin-bonded retainers. Twenty metal replicas of the prepared teeth were made (10 for each tooth morphotype). Resin-bonded retainers 0.5 mm thick were made for the 40 replicas and luted with Panavia EX cement. Forces for dislodgment of the retainers were applied along the long axes of the teeth. Forces recorded at the time of dislodgment were analyzed with 2-way analysis of variance and the post hoc Scheffé test.\u0000\u0000\u0000RESULTS\u0000Grooves resulted in substantial increases in debonding forces for maxillary molars (P<.001). The effect of grooves on mandibular second molars was not significant (P=.13).\u0000\u0000\u0000CONCLUSION\u0000Grooves placed in tooth preparations of maxillary molar teeth for resin-bonded retainers had a significant effect on retention/resistance. The effect of grooves on mandibular second molars was less pronounced.","PeriodicalId":185384,"journal":{"name":"The Journal of prosthetic dentistry","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126208188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}