Randomized clinical trial of adhesive restorations in primary molars. 18-month results.

PURPOSE: To evaluate the clinical performance of adhesive restorations of resin composite and resin-modified glass-ionomer cements in primary molars. METHODS: This randomized clinical trial included subjects (5-9 year-old children) selected at two university centers (UFRGS and UNIFRA). The sample consisted of 132 primary molars presenting active cavitated carious lesions (with radiographic involvement of the inner half of the dentin), located on the occlusal and occlusal-proximal surface. The sample was randomly divided into three groups, according to the restorative material: (G1) universal restorative system (Adper Single Bond 2 system and Filtek Z350); (G2): Resin-modified glass-ionomer cement (Vitremer); and (G3): Low shrink restorative system (Filtek P90). The restorations were clinically and radiographically followed every 6 months for up to 18 months using the USPHS modified criteria for clinical evaluation. Survival estimates for restoration longevity were evaluated using the Kaplan-Meier method. Log-rank test (P< 0.05) was used to compare the differences in the success rate according to the type of the restorative material. RESULTS: The type of restorative material used did not influence the longevity of the restorations. After clinical follow-up, there was no statistical difference in the rates of success for the three materials used to restore active cavitated carious lesions in primary molars. The survival rates for the follow-up were similar regarding the number of restored surfaces and the caries removal technique (partial or complete). Mean estimated time of survival was 17.2 months (95% CI: 16.7-17.7). Estimated survival rates of the restorations were 100%, 98%, 88% and 65% at 1, 6, 12 and 18 months of clinical evaluations, respectively.

Analysis of transmittance and degree of conversion of composite resins.

The objective of this study was to evaluate and correlate light transmittance (T), initial degree of conversion (IDC), and degree of conversion after 24 hr (DC24) for 22 composite resins (CR) for enamel and dentin use. The transmittance (n = 10) was measured with a spectrometer at a wavelength of 468.14 nm. The degree of conversion (DC; n = 5) was measured with Fourier Transform Near-Infrared Spectroscopy before polymerization, immediately after photoactivation, and 24 hr after photoactivation. Both sets of values are provided as percentages. ANOVA and Games-Howell (α = 5%) tests showed that Filtek Supreme Ultra gave the highest T values of all enamel CRs, while Esthet-X HD presented the lowest. Meanwhile, Venus diamond gave the highest values of all dentin CRs, while Esthet-X HD gave the lowest. For IDC and DC24, ANOVA showed differences between individual CRs and the two CR types (p < .0001). Despite the limitations of this study, it can be concluded that there was no correlation between T and either IDC or DC24 (p > .05); however, IDC and DC24 were strongly correlated (p < .05) by Pearson's correlation. That being said, as a higher DC reflects better mechanical properties, certain conclusions can be drawn about overall performance. The best IDC values were observed for the Opallis enamel resin and the Opallis and Premise dentin resins. Meanwhile, the best DC24 values were observed for the Opallis, Charisma, and Premise enamel resins and the Opallis and Premise dentin resins. Degree of conversion and light transmittance showed differences between composite resin types (enamel and dentin) and brands. It is important to know at the moment of composite choice taking into account mechanical and optical properties.

Evaluation of mechanical properties on three nanofilled composites.

The purpose of this study was to evaluate the mechanical behavior of three composites with nanoparticles Filtek Z350 XT (3M ESPE), Esthet X (Dentsply), Grandio (Voco) in enamel and body shades (A2) trough nanohardness, elastic modulus, compressive strength test, flexural strength test, diametral tensile strength, flexural modulus, weight filler content and Knoop microhardness. One sample of each material was submitted to nanohardness and elastic modulus. Five values of ten indentations were considered valids inside confidence intereval. Ten samples of each material were submitted to compressive strength, flexural strength and diametral tensile strength test at universal testing machine. The flexural modulus test was calculated based on flexural strength results. Ten samples of each group were submitted to knoop microhardness test. The results were submitted to ANOVA and Tukey statistical tests. The highest inorganic weight filler content for Grandio was registered after the organic mould decomposition. After statistical analysis Grandio showed the highest averages for nanohardness, elastic modulus, flexural modulus and knoop microhardness. For diametral tensile strength Grandio and Filtek Z350 XT obtained the highest averages. The tested composite resins ranged similar medias statistically for compressive strength. For flexural strength Filtek Z350 XT and Esthet X showed the highest averages. The results suggest that the weight filler content, the filler size and shape and the contact surface between nanofillers and organic phase has direct relation with composite resins with nanoparticles mechanical properties. Further studies should be carried out to improve the knowledge of composites with nanoparticles mechanical behavior.

Avaliação clínica de restaurações de resina composta em dentes posteriores / Clinical evaluation of composite restorations in posterior teeth

Este estudo avalia o comportamento clínico de restaurações diretas de resina composta em dentes posteriores. Para tanto, toma uma série de casos de acompanhamento longitudinal, com a realização de 55 restaurações de classe I e II. Os operadores são alunos de Odontologia do Centro Universitário Franciscano (Unifra, RS). A avaliação foi feita seis meses após a confecção das restaurações, e foi utilizado o critério United States Public Health Service (USPHS) modificado: forma anatômica, estabilidade da cor, descoloração marginal, integridade marginal e lesão de cárie secundária. Foram avaliadas 54 (98,2%) restaurações, delas, duas falharam, e o índice de sobrevivência foi de 91,78%. Conclui que o desempenho clínico das restaurações é aceitável.

This article aims to evaluate the clinical performance of direct composite resin restorations in posterior teeth. Methods: Case series of longitudinal, with the completion of 55 restorations, class I and II. The operators were dental students from Franciscan University Center (Unifra) RS, Brazil. The evaluation was conducted six months after making these, and criterion was utilized United States Public Health Service (USPHS) modified: anatomical form, color stability, marginal discoloration, marginal integrity and caries secondary. A total of 54 (98.2%) restorations, of whom two failed, and the survival rate was 91.78%. In conclusion, it finds that the clinical performance of the restorations was acceptable.