Diabetes triggers the loss of tooth structure associated to radiographical and histological dental changes and its evolution to progressive pulp and periapical lesions in rats.

OBJECTIVES: The aim of this study was to evaluate the putative influence of diabetes without metabolic control in the loss of tooth structure as well as histological changes in dentin and pulp tissue in rats. DESIGN: Diabetes was induced in Wistar rats (n=25) by intravenous administration of alloxan (42 mg/kg). Diabetic and non-diabetic control rats were evaluated at 1, 3, 6, 9 and 12 months of follow-up. In order to evaluate the presence and progression of dental caries and periapical lesions, hemimandibles were removed and submitted to radiographical, histological, and morphometrical procedures. RESULTS: Dental caries were detected after radiographical and histological evaluations in diabetic group from the third month of diabetes onset, increasing gradually in frequency and severity in periods. Diabetic rats dental pulps also presented significant reduction in volume density of collagen fibers and fibroblasts at third month, parallel with a trend towards the increase in inflammatory cells volume density. Diabetic rats presented a generalized pulp tissue necrosis after 6 months of diabetes induction. Moreover, periapical lesions were not detected in control group, while these lesions were observed in all rats after 3, 6, 9, and 12 months of diabetes induction. CONCLUSIONS: Uncontrolled diabetes seems to trigger the loss of tooth structure, associated to histological dental changes and mediates its evolution to progressive severe pulp and periapical lesions in rats. Therefore, diabetes may be considered a very important risk factor regarding alterations in dental pulp, development of dental caries, and periapical lesions.

Princípios e técnica de preparos dentários para restaurações de resina composta em dentes posteriores / Fundamental concepts and tooth preparation for direct posterior composites

O sistema restaurador adesivo de uso direto tem sido amplamente estudado e aperfeiçoado nos últimos anos. Isso possibilitou o aumento da faixa de utilização das resinas compostas em dentes posteriores, que até ADA1 (1998) eram restritas às restaurações profiláticas e preventivas em lesões incipientes. São inúmeros os fatores que podem influenciar na longevidade de restaurações adesivas diretas em dentes posteriores. O preparo do dente é fundamental para que este possa receber a restauração. Os princípios para preparos cavitários enunciados por Black4 (1908), sofreram algumas adaptações em seus conceitos e interpretações devido aos novos instrumentos, materiais e abordagens terapêuticas preventivas disponíveis atualmente.No entanto, todos os princípios ainda devem ser considerados durante o preparo dos dentes que receberão restaurações de resina composta aplicando os conceitos atuais. Conhecimento sobre aspectos de preservação de estrutura dentária, adequada forma de resistência e retenção, e técnicas de acabamento marginais são essenciais. Assim, o objetivo deste artigo é demonstrar alguns aspectos do preparo dos dentes posteriores para que possam favorecer a longevidade das restaurações de resina composta, pela aplicação dos conceitos modernos respeitando porém os princípios clássicos de preparos cavitários.

During the past few decades, direct dental materials have changed dentistry’s approach to diagnosis and management of dental caries. The potential uses of resin-based composites in restorative dentistry are expanding. Many factors contribute to the realization of clinical success with direct posterior composite restorations. Cavity preparation is essential for the clinical outcome. For many years the Black tooth preparations, with few modifications, formed the basis for most operative preparation procedures. Modifications of tooth preparation have resulted from improvements in restorative materials, instruments, and techniques, and the increased knowledge, however, Black’s principles of tooth preparation are still relevant. The restoration of posterior teeth with directly placed resin-bonded composite requires meticulous operative technique in order to ensure success. Conservation of tooth structure retention form, resistance form, and procedures for finishing the external walls of the tooth preparation all present a series of challenges that dentists and are essential. Thus, this article will address the principles, techniques, and other considerations during cavity preparation for achieving clinical success with direct posterior composite resin restorations.