Alteração óssea radiográfica pós-carregamento em próteses totais fixas implantossuportadas : análise de textura e níveis de cinza

Abstract

The literature has shown that the bone tissue may undergo remodeling under mechanical stimuli. Therefore, it is necessary to assess if the prosthetic loading of dental implants can change the peri-implant bone characteristics. The aim of this study was to evaluate the bone changes in distal implants of implant supported fixed complete dentures (PTFIs) by means of gray levels and texture analysis in periapical radiographs. The sample consisted of 63 distal implants of PTFIs. The radiographs were taken after the prostheses installation (T0), 1 year (T1) and 3 years (T3) in function. The images of each implant at different times were superimposed using the software GIMP® and then exported to the software ImageJ®, where the Regions of Interest (ROIs) were selected for the analyses of the following gray levels variables: mean gray levels, standard deviation and coefficient of variation; and the texture variables: correlation, contrast, entropy and angular second moment. Data were analyzed by suing mixed regression models at the significance level of 0.05. Statistically significant effects were found for time in one year (P < 0.05) and in 3 years (P < 0.01) and for maximum bite force (P < 0.01) on mean gray levels increase. The interaction between time in one year and bruxism was significant (P < 0.01) for reduction of the coefficient of variation. No significant effect was found for texture variables (P > 0.05). The results suggest an increase of bone density close to distal implants of PTFIs in a period of time up to 3 years as measured by the increase in mean gray levels and reduction of coefficient of variation in a period of 1 year.