Pilares cerâmicos utilizados na Odontologia: revisão de literatura / Ceramic abutments used in Dentistry: a literature review

A busca pela excelência estética e funcional nas reabilitações com próteses implantossuportadas necessita que a restauração tenha harmoniosa integração visual da coroa protética com a arcada dentária, além de ter a capacidade de suportar carga funcional. Para isso, a seleção do pilar protético é fundamental, permitindo similaridade de cor e translucidez em relação à estrutura dentária natural. Embora os pilares de titânio sejam considerados padrão ouro para a reabilitação implantossuportada, estes podem interferir negativamente na estética fnal do caso, pois, em algumas situações, é possível visualizar o metal através da margem da gengiva. A fm de solucionar esse problema, surgem os pilares de cerâmica, desempenhando um papel fundamental na capacidade de mimetizar o elemento dental natural equivalente. Nesse sentido, o objetivo deste estudo foi, através de uma revisão da literatura, discutir os principais aspectos relacionados aos pilares cerâmicos utilizados em reabilitações implantossuportadas

To achieve aesthetic and functional excellence in rehabilitation with implant prostheses, the restorations should have harmonious visual integration of the prosthetic crown with the dental arch, and have the ability to withstand functional load. For this, the selection of the abutment is essential, allowing similarity of color and translucency in relation to natural tooth structure. Although the titanium abutments are considered the gold standard for implant-supported rehabilitation, they can adversely affect the fnal aesthetics of the case because, in some situations, the metal through the gingival margin may be seen. In order to solve this problem, ceramic abutments play a key role in the ability to mimic the natural dental element. In this context, the objective of this study was, through a literature review, discuss the main aspects related to ceramic abutments used in implant-suported rehabilitation

Marginal adaptation of class V composite restorations submitted to thermal and mechanical cycling.

OBJECTIVE: This study evaluated the effect of the margin location and an adhesive system on the marginal adaptation of composite restorations. MATERIAL AND METHODS: Class V cavities were prepared in bovine teeth with the gingival margin on the dentin and the incisal margin on the enamel. The cavities were restored with a micro-hybrid composite resin using an etch-and-rinse [Single Bond 2 (SB)] or a self-etching adhesive [Clearfil SE Bond (CL)]. After finishing and polishing the restorations, epoxy replicas were prepared. The marginal adaptation was analyzed using scanning electronic microscopy (SEM, 500 x magnification). The higher gap width in each margin was recorded (T0). After the first evaluation, the samples were submitted to thermal cycling (2,000 cycles of 5°C±2°C followed by 55°C±2°C - T1) and mechanical cycling (100,000 cycles of 50 kN and 2 Hz - T2). Replicas of samples were rebuilt after each cycling and analyzed under SEM. The data were submitted to Mann-Whitney, Wilcoxon and Friedman testing (α=0.05). RESULTS: The SB presented higher gaps in the dentin than the enamel, while there was no difference between the substrate for the CL. In the dentin, the CL showed better marginal sealing than the SB. The opposite occurred in the enamel. There were no significant differences between the baseline, thermal and mechanical cycling for any experimental condition. CONCLUSIONS: The outcomes of the present study showed that the adhesive system and margin location have an important effect on the marginal adaptation of composite restorations.

Marginal adaptation of class V composite restorations submitted to thermal and mechanical cycling

Objective: This study evaluated the effect of the margin location and an adhesive system on the marginal adaptation of composite restorations. Material and Methods: Class V cavities were prepared in bovine teeth with the gingival margin on the dentin and the incisal margin on the enamel. The cavities were restored with a micro-hybrid composite resin using an etch-and-rinse [Single Bond 2 (SB)] or a self-etching adhesive [Clearfil SE Bond (CL)]. After finishing and polishing the restorations, epoxy replicas were prepared. The marginal adaptation was analyzed using scanning electronic microscopy (SEM, 500 x magnification). The higher gap width in each margin was recorded (T0). After the first evaluation, the samples were submitted to thermal cycling (2,000 cycles of 5°C±2°C followed by 55°C±2°C – T1) and mechanical cycling (100,000 cycles of 50 kN and 2 Hz – T2). Replicas of samples were rebuilt after each cycling and analyzed under SEM. The data were submitted to Mann-Whitney, Wilcoxon and Friedman testing (á=0.05). Results: The SB presented higher gaps in the dentin than the enamel, while there was no difference between the substrate for the CL. In the dentin, the CL showed better marginal sealing than the SB. The opposite occurred in the enamel. There were no significant differences between the baseline, thermal and mechanical cycling for any experimental condition. Conclusions: The outcomes of the present study showed that the adhesive system and margin location have an important effect on the marginal adaptation of composite restorations.

Effect of curing unit and adhesive system on marginal adaptation of composite restorations.

This study sought to evaluate how a curing unit and adhesive system affected the marginal adaptation of resin composite restorations. Class V cavities were prepared in bovine teeth with a gingival margin in dentin and an incisal margin in enamel. The cavities were restored with a micro-hybrid resin composite using one of four adhesives: Single Bond 2, Prime & Bond NT, Clearfil SE Bond, Xeno IV. The light-activations were performed using a quartz-tungsten-halogen (QTH) lamp or a second-generation light-emitting diode (LED). Restorations were finished and polished and epoxy replicas were prepared. Marginal adaptation was analyzed by using scanning electronic microscopy (magnification 500X). The widest gaps in each margin were recorded, and data were submitted to Kruskal-Wallis, Mann-Whitney, and Wilcoxon tests (α = 0.05). Differences between the adhesives were observed only when the dentin margins were evaluated: Clearfil SE Bond demonstrated better marginal adaptation than Prime & Bond NT or Single Bond 2 (which demonstrated the widest gaps in the dentin margin). The type of curing unit only affected the results for Xeno IV when the enamel margin was analyzed; the LED lamp promoted smaller gaps than the QTH lamp.

Avaliação de métodos para mensuração da adaptação marginal e espessura de linha de cimentação em restaurações indiretas / Evaluation of methods for measurement of marginal adaptation and cement thickness on indirect restorations

Objetivos: Comparar métodos utilizados na mensuração da adaptação marginal e espessura de linha de cimentação em restaurações indiretas do tipo inlay. Materiais e método: Foram confeccionados preparos cavitários para inlay em 24 terceiros molares humanos, assim como restaurações inlays em resina composta. Metade das amostras foi utilizada para avaliar, sem a cimentação da restauração, a adaptação marginal, ao passo que as demais foram cimentadas e a espessura da linha de cimentação foi mensurada. Foram feitas avaliações nas regiões cervical, interproximal e oclusal, utilizando-se três metodologias: lupa estereoscópica, microscopia óptica e microscopia eletrônica de varredura, sendo que com esta última avaliou-se apenas a região oclusal. Resultados: Para avaliação da adaptação marginal, não houve diferença entre a lupa estereoscópica e microscopia óptica. Quando foi mensurada a linha de cimentação, a lupa apresentou menor valor na região interproximal. A microscopia eletrônica de varredura apresentou os menores valores. Conclusões: Para medir adaptação de peças em um preparo pode-se utilizar tanto lupa estereoscópica quanto microscopia óptica. Para avaliar a linha de cimentação o melhor método é MEV.

Effect of cavity preparation design on the fracture resistance of directly and indirectly restored premolar

Aim: The aim of this study was to evaluate the fracture resistance of human premolars with extensive cavity preparations of the inlay and onlay types, for performing direct and indirect composite resin restorations. Methods: Eight-four premolars were divided into 7 groups (n=12): G1=intact teeth; G2=inlay/Filtek Z-250 direct; G3=inlay/ Filtek Z-250 light polymerized indirectly; G4=inlay/ Solidex; G5=onlay/ Filtek Z-250 direct; G6=onlay/ Filtek Z-250 light polymerized indirectly; G7=onlay/ Solidex. Indirect Filtek Z- 250 restorations were light activated using the EDG-lux oven. All samples were submitted to axial compression load in a Universal Testing Machine until fracture. The data were submitted to the one-way ANOVA and Tukey’s test (a=0.05). Results: The results (N) were: G6-1938a, G5-1570ab, G7-1285b, G1-1215b, G4-1174b, G3-1146b and G2-1112b. The onlay cavities restored indirectly with Filtek Z-250 presented significantly higher fracture resistance (G6) than the other groups, except for onlay restorations made directly with Filtek Z-250 (G5), which, in turn, did not differ significantly from the other groups. However, the onlay restorations made with Filtek Z-250 led to more catastrophic failure modes. Conclusions: 1. Adhesive inlay restorations, irrespective of the type of composite resin and light-activation technique used, restored the fracture resistance of intact teeth.

Electrognathographic evaluations of rehabilitated edentulous patients.

This study investigated, through computerized electrognathographic evaluations (K6-I Diagnostic System, Myotronics-Noromed Inc., Tukwila, USA), the mandibular movement pattern of 16 patients rehabilitated with complete dentures presenting no symptoms of stomatognathic functional alterations. The patients were instructed to wear an intra-oral appliance for occlusal plane coverage over their usual superior denture and were then rehabilitated with new dentures preserving a free-way space of 3 mm. After sixty days, the occlusal vertical dimension was increased and the modified inferior dentures were used for another 60 days. The obtained results were submitted to the Tukey Test and to the Friedman test, depending on which variable was under consideration, both at a significance level of 5%. The data revealed a significant decrease in free-way space when the first and the last evaluations were compared. No significant differences were found during opening and closing. It was concluded that the presence of a free-way space at the end of the treatment confirms the importance of its existence for maintaining the balance of the masticatory system, assuming the occurrence of a postural repositioning.

Electrognathographic evaluations of rehabilitated edentulous patients

This study investigated, through computerized electrognathographic evaluations (K6-I Diagnostic System, Myotronics-Noromed Inc., Tukwila, USA), the mandibular movement pattern of 16 patients rehabilitated with complete dentures presenting no symptoms of stomatognathic functional alterations. The patients were instructed to wear an intra-oral appliance for occlusal plane coverage over their usual superior denture and were then rehabilitated with new dentures preserving a free-way space of 3 mm. After sixty days, the occlusal vertical dimension was increased and the modified inferior dentures were used for another 60 days. The obtained results were submitted to the Tukey Test and to the Friedman test, depending on which variable was under consideration, both at a significance level of 5 percent. The data revealed a significant decrease in free-way space when the first and the last evaluations were compared. No significant differences were found during opening and closing. It was concluded that the presence of a free-way space at the end of the treatment confirms the importance of its existence for maintaining the balance of the masticatory system, assuming the occurrence of a postural repositioning.

O objetivo deste estudo foi avaliar por meio de eletrognatografia computadorizada (K6-I Diagnostic System, Myotronics-Noromed Inc., Tukwila, EUA) o padrão dos movimentos mandibulares de 16 pacientes reabilitados com dentaduras completas, livres de alterações funcionais do sistema estomatognático. Os pacientes foram instruídos a utilizar um aparelho intra-oral de cobertura oclusal plana adaptado na prótese usual superior e então reabilitados com novas próteses preservando a existência de um espaço funcional livre de 3 mm. Após 60 dias promoveu-se um aumento da dimensão vertical de oclusão e as próteses inferiores assim modificadas foram utilizadas por mais 60 dias. Os resultados foram submetidos ao Teste de Tukey e ao Teste de Friedman, dependendo da variável em estudo, ambos com 5 por cento de significância. Constatou-se decréscimo significante do espaço funcional livre quando compararam-se a primeira e a última avaliações. Não foram encontradas diferenças durante abertura e fechamento. Concluiu-se que a presença de um espaço funcional livre ao final do tratamento vem comprovar a importância de sua existência na manutenção do equilíbrio do sistema mastigatório, admitindo-se que ocorre o reposicionamento postural.

Assessment of painful symptomology in patients with temporomandibular disorders by means of a combined experimental scale

Quantification and assessment of the evolution of painful symptomology in patients with temporomandibular disorders, during the pre-, trans- and post-therapeutic stages is one of the greatest difficulties found by dental surgeons. Various authors have studied and discussed the use of verbal and non-verbal scales for this purpose. Therefore, this study aimed, by means of a combined experimental scale, to assess the evolution of painful symptomology in patients with completely edentulous maxilla and partly edentulous mandible, with Class I or Class II Kennedy prosthetic spaces, treated with flat occlusal appliances, before, during and after 150 of starting treatment. A selection was made of 16 patients with a mean age of fifty-two years, with signs and symptoms of temporomandibular disorders and diminished vertical occlusion dimension. The patients were submitted to treatment with flat occlusal appliances and fortnightly consultations for a period of 150 days. During these consultations, patients recorded their painful symptomology on a combined experimental pain scale. The results obtained were grouped into tables and submitted to the Friedman Test at a level of 5% probability. These revealed statistically significant differences between the values obtained at each assessment made. According to the methodology used and the results obtained, it was concluded that the therapy used was effective and that the experimental scale was efficient for registering the evolution of the symptoms initially detected.