Metal-ceramic partial fixed dentures: a retrospective study / Estudo retrospectivo de próteses parciais fixas metalocerâmicas

ABSTRACT Objective Metal-ceramic prosthesis are the treatment of choice in oral rehabilitation because of their high survival rates. However, there are few reports in the scientific literature about factors that lead to fractures of metal-ceramic prostheses. The aim of this study was to evaluate whether prostheses units number, abutment type and number, type of the prostheses, prostheses position in the mouth, bruxism and occlusal plaque influence the incidence of fractures in fixed metal-ceramic prostheses. Methods For this study, 16 patients were selected, totaling 74 metal-ceramic prostheses installed between 2000-2010, with follow up of at least four years. Besides dental history, other information was collected, such as patients' gender and age, prostheses installation date, and the ceramic system used. In case of prostheses fracture, a questionnaire was applied to identify signs of bruxism. A clinical evaluation was done to evaluate the prostheses integrity and opposing dentition characteristics. Success, failure and survival rates were determined. Results The results showed that the success rate of metal-ceramic prostheses was 87.8% and the survival rate was 89.1%. In addition, the success rate was independent of patient age, prostheses installation time, number of prosthesis, number of prosthesis' units and abutments. The qualitative variables also did not show significant statistical results between success and failure rates. Conclusion It was concluded that metal-ceramic prostheses have high success and survival rates, what guarantees longevity and indication of this type of prostheses in daily practice.

RESUMO Objetivo As próteses metalocerâmicas apresentam altas taxas de sobrevivência e, por isso, são indicadas para diversos casos em reabilitação oral. Entretanto, na literatura científica, existem poucos relatos clínicos sobre os fatores que levam à fratura dessas restaurações. Diante do exposto, o presente estudo teve como objetivo avaliar se a quantidade de elementos que compõem a prótese, se a quantidade de elementos por retentor, se o tipo de prótese e tipo de pilar, bem como sua localização, e o bruxismo, influenciam ou não nas fraturas dessas restaurações indiretas. Métodos Para isso, selecionaram-se 74 próteses metalocerâmicas, instaladas entre 2000 e 2010 em 16 pacientes, com acompanhamento mínimo de quatro anos. Foram coletadas informações dos pacientes, como: gênero, idade, data da instalação das próteses e cerâmica utilizada. Durante a avaliação clínica, observou-se a integridade da prótese e, em caso de fratura, coletava-se informações sobre a história clínica. As características do dente antagonista também foram avaliadas. Além disso, aplicou-se um questionário, com o intuito de identificar a provável presença de bruxismo. Resultados Como resultado, tem-se que a taxa de sucesso das próteses metalocerâmicas foi de 87,8% e, a taxa de sobrevivência, foi de 89,1%. A taxa de sucesso não teve influência da idade, tempo de instalação, número de próteses na boca, número de elementos ou pilares. Conclusão Embora pouco frequente, a fratura da cerâmica de cobertura foi a complicação mais comum. As próteses metalocerâmicas possuem altas taxas de sobrevida e de sucesso, o que garante a longevidade e a indicação desse tipo de restauração.

Marginal adaptation of CAD-CAM onlays: Influence of preparation design and impression technique.

STATEMENT OF PROBLEM: Factors that may affect the marginal adaptation of computer-aided design and computer-aided manufacturing (CAD-CAM) restorations include preparation design, impression technique, and CAD-CAM system. The influence of impression technique and preparation design on CAD-CAM partial coverage restorations has not been fully addressed. PURPOSE: The purpose of this in vitro study was to investigate the influence of direct and indirect digital scanning techniques and 2 preparation designs on the marginal adaptation of CAD-CAM onlays. MATERIAL AND METHODS: Two mesio-occlusal buccal onlay preparations with reduction of the mesiobuccal cusp were made: conventional preparation (CP) with a 1.2-mm modified shoulder margin and modified preparation (MP) flat cuspal reduction without shoulder. Virtual models were generated from each preparation by using a digital scanner (BlueCam; Dentsply Sirona) from the plastic teeth (direct digital scan) or from the stone dies (indirect digital scan). Onlays were designed using a CAD-CAM system (CEREC 4.0; Dentsply Sirona), and nanoceramic resin blocks (Lava Ultimate Restorative; 3M ESPE) were milled using the CEREC MCX milling machine. Marginal discrepancy was evaluated using an optical stereomicroscope at ×25 magnification in 18 locations distributed along the margins of the preparation. The data were analyzed by using 3-way ANOVA followed by the Tukey HSD test (α=.05). RESULTS: CP presented a statistically significant reduced average marginal adaptation (59 ±50 µm) than did MP (69 ±58 µm) (P<.001). The Tukey HSD test showed the presence of a significantly larger marginal discrepancy in the mesial and buccal locations of MP when compared with CP. Regarding impression techniques, the buccal location presented the smallest average marginal discrepancy in restorations fabricated with indirect impression when compared with direct impression (42 ±33 µm and 60 ±39 µm) (P<.001). CONCLUSIONS: The results showed that conventional preparation with a modified shoulder margin presented improved marginal adaptation compared with modified preparation with flat cuspal reduction. Direct and indirect digital scanning techniques produced restorations within a clinically acceptable range; however, the indirect scanning technique resulted in the fabrication of restorations with superior marginal adaptation on the buccal location.

Susceptibility to Coffee Staining during Enamel Remineralization Following the In-Office Bleaching Technique: An In Situ Assessment.

PURPOSE: To assess in situ the enamel mineralization level and susceptibility to coffee staining after in-office bleaching. MATERIALS AND METHODS: Thirty-six human dental fragments assembled into intraoral devices were bleached with 35% hydrogen peroxide and treated as follows: (group 1) no contact with coffee; (group 2) immersion in a coffee solution for 30 minutes daily for 7 days, starting 1 week after bleaching; and (group 3) immersion in a coffee solution for 30 minutes daily for 14 days, starting immediately after bleaching. Enamel mineralization and color were assessed before bleaching (T1), immediately after bleaching (T2), and after 7 (T3) and 14 days (T4). The CIE whiteness index (W*) and closeness to white (ΔW*) following bleaching and/or immersion in coffee were calculated. Data were analyzed with Friedman and Wilcoxon tests or Kruskal-Wallis and Mann-Whitney U-tests (α = 0.05). RESULTS: Significant differences in the mineralization levels were observed as a function of time. No significant differences in W* were observed between groups, nor was W* significantly different at T3 and T4. Similar ΔW* was observed between groups after 7 or 14 days. CONCLUSIONS: The mineral loss after in-office bleaching was progressively reversed by contact with saliva for 14 days. The whiteness index was not affected by contact with coffee during the remineralization period. CLINICAL SIGNIFICANCE: The results of this in situ study suggest that the mineral loss caused by in-office dental bleaching is minimal and is partly compensated by remineralization due to contact with saliva. Additionally, whiteness was not affected by daily exposition to coffee during the enamel remineralization, which indicates that avoiding the consumption of coffee immediately following in-office bleaching is unnecessary. (J Esthet Restor Dent 28:S23-S31, 2016).

Avaliação da resistência à fadiga e modalidades de danos de coroas unitárias de dissilicato de lítio e resina nanocerâmica / Evaluation of the fatigue resistance and damage modes of lithuim disilicate and resin nanoceramic

Fraturas completas ou por delaminação são causas frequentes de insucesso entre coroas unitárias cerâmicas. O uso de materiais à base de resina composta, em contraponto à natureza friável das cerâmicas, parece ser uma alternativa para coroas posteriores, uma vez que apresentam processo de fabricação e reparo simplificados. Este estudo avalia a resistência à fadiga de coroas unitárias monolíticas CAD/CAM de resina composta nanocerâmica e cerâmica reforçada por dissilicato de lítio, bem como os danos causados pela aplicação de carga cíclica. Vinte e seis coroas monolíticas (n=13) foram cimentadas sobre réplicas de resina composta de um molar preparado e submetidas à ciclagem mecânica durante 2 milhões de ciclos, sob carga máxima de 350N à frequência de 2 Hz. Não foram observadas fraturas catastróficas ou fratura coesiva das coroas, resultando em sobrevivência de 100% para os dois materiais avaliados. As coroas foram incluídas em resina epóxi e desgastadas progressivamente à procura de danos. Coroas em resina nanocerâmica apresentaram-se íntegras, com trincas do cone externo, trincas do cone interno e com trincas radiais. As coroas em dissilicato de lítio apresentaram trincas do cone externo e interno, algumas atingindo a superfície interna. Os danos receberam escores de acordo com a severidade. Os dados foram submetidos à análise estatística pelo teste de Mann-Whitney (p =0,462), que não revelou diferenças estatísticas em relação aos danos observados. Concluímos que coroas monolíticas em dissilicato de lítio e resina nanocerâmica podem ser utilizadas na região posterior, pois apresentaram resistência à fadiga equivalente, sem diferença estatística entre os danos apresentados.(AU)

Bulk fractures or cohesive fractures are frequent complications for ceramic crowns. The use of resin- based materials, in contrast to the brittle nature of ceramics, seems to be an alternative to posterior crowns, since these materials present simplified manufacturing and repair tehniques. This study evaluates the fatigue resistance of monolithic CAD / CAM crowns made of resin nanoceramic and lithium disilicate reinforced ceramic, as well as the damage modes caused by the application of cyclic loading. Twenty-six monolithic crowns (n = 13) were cemented to a composite resin replica of a prepared molar and subjected to cyclic load over 2 million cycles under maximum load of 350N, at a frequency of 2 Hz. The crowns presented no catastrophic failures or cohesive fractures, resulting in survival of 100% for both materials. The crowns were embedded in epoxy resin and gradually grinded for damage analisys. Nanoceramic resin crowns presented no damage, outer cone cracks, inner cone cracks and radial cracks. Lithium disilicate crowns showed outer and inner cone cracks, some of the latter reaching the inner surface. Specimens were scored according to the severity of damage. Data was subjected to Mann-Whitney test (p = 0.462), which revealed no statistical difference. We conclude that lithium disilicate and resin nanoceramic monolithic crowns can be used in the posterior area, since they presented comparable fatigue resistance, with no statistical difference between damage modes.(AU)

Current panorama of temporomandibular disorders' field in Brazil.

UNLABELLED: In 2012, the recognition of the specialty of Temporomandibular Disorders and Orofacial Pain completed ten years. Given this scenario, it is extremely important to track the current situation of this field of knowledge in Brazil, specifically in the area of research and training. We hope to discuss the importance of the recognition of this specialty and the inclusion of these subjects in undergraduate programs in Dentistry. OBJECTIVE: The objective of this study is to perform a bibliometric survey of researches regarding Temporomandibular Disorders and Orofacial Pain conducted in the country, determine the number of specialization courses in Orofacial Pain and the number of specialists in the field. METHODS: The bibliometric survey was conducted based on the Dissertations Portal of Coordination for the Improvement of Higher education Personnel (CAPES) and on PubMed. The panorama of the field of Orofacial Pain and Temporomandibular disorders in Brazil was determined by searching on the website of the Brazilian Council of Dentistry. RESULTS: We found 731 theses and dissertations with Temporomandibular Disorders and Orofacial Pain as the main subjects; 81 accredited/recognized Courses on Orofacial Pain and Temporomandibular Dysfunction completed; 8 accredited/recognized Specialization Courses on Orofacial Pain and Temporomandibular Dysfunction still in progress, and 1,064 registered specialists in Orofacial Pain and Temporomandibular Dysfunction in the Brazilian Council of Dentistry. Search in the PUBMED database yielded 576 articles published with the participation of Brazilian researchers as first authors and/or co-authors in the period from 2000 to 2013. From this amount, only 5 were published in Portuguese, while all the others were published in english. We can also notice that the number of published articles increases over time. CONCLUSION: The number of researches related to temporomandibular disorders has increased over the last ten years, as well as the number of specialization courses and the number of specialists, which represents a major breakthrough for this field of knowledge.

Current panorama of temporomandibular disorders' field in Brazil

In 2012, the recognition of the specialty of Temporomandibular Disorders and Orofacial Pain completed ten years. Given this scenario, it is extremely important to track the current situation of this field of knowledge in Brazil, specifically in the area of research and training. We hope to discuss the importance of the recognition of this specialty and the inclusion of these subjects in undergraduate programs in Dentistry. Objective: The objective of this study is to perform a bibliometric survey of researches regarding Temporomandibular Disorders and Orofacial Pain conducted in the country, determine the number of specialization courses in Orofacial Pain and the number of specialists in the field. Methods: The bibliometric survey was conducted based on the Dissertations Portal of Coordination for the Improvement of Higher education Personnel (CAPES) and on PubMed. The panorama of the field of Orofacial Pain and Temporomandibular disorders in Brazil was determined by searching on the website of the Brazilian Council of Dentistry. Results: We found 731 theses and dissertations with Temporomandibular Disorders and Orofacial Pain as the main subjects; 81 accredited/recognized Courses on Orofacial Pain and Temporomandibular Dysfunction completed; 8 accredited/recognized Specialization Courses on Orofacial Pain and Temporomandibular Dysfunction still in progress, and 1,064 registered specialists in Orofacial Pain and Temporomandibular Dysfunction in the Brazilian Council of Dentistry. Search in the PUBMED database yielded 576 articles published with the participation of Brazilian researchers as first authors and/or co-authors in the period from 2000 to 2013. From this amount, only 5 were published in Portuguese, while all the others were published in english. We can also notice that the number of published articles increases over time. Conclusion: The number of researches related to temporomandibular disorders has increased over the ...

Stepwise excavation in a permanent molar: 17-year follow-up.

The current study presents a 17-year clinical report of stepwise excavation and indirect pulp capping in a lower right first molar, with great dentin destruction and a lack of dentin support of the cusps. At the first appointment, indirect pulp capping with calcium hydroxide and a temporary filling with zinc oxide cement were performed to minimize the risk of pulp exposure during excavation. After 45 days, the remaining carious tissue was removed and a restoration with glass-ionomer lining (Vitrebond) and resin composite (P-50) was performed. Satisfactory morphology and function of the restoration and pulp vitality were preserved for 17 years, thus indicating that stepwise excavation can be a good treatment alternative in selected cases.