Quantitative analysis of smear layer after carious tissue removal by ultrasound and air abrasion

• Grant number: 05/02437-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2006
• End date: December 31, 2007
• Field of knowledge: Health Sciences - Dentistry - Pediatric Dentistry
• Principal Investigator: Lourdes Aparecida Martins dos Santos-Pinto
• Grantee: Ana Carolina Mascarenhas Oliveira
• Host Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

Smear layer is produced on dentin surface after cut by rotate instrument. This layer interfere in dentin permeability and consequently on the restorative material adhesion. Recently, new technologies such as air abrasion and CVD systems have been used for dental cavity preparations. The aim of this study is to carry out a scanning electron microscopic (SEM) analysis of the quality of smear layer produced in cavities prepared with traditional diamond bur, CVD tip and air abrasion system. Sixty bovine incisors will be used in this study. The crowns will be cut in two halves, one half will be kept with sound dentin and in the other one, artificial caries will be produced. Cavities (2x2x2mm) will be prepared in each tooth surface using diamond dental bur with high speed (KG Sorensen 1013), CVD tip with ultrason (CVDentus 8.3231-1) and air abrasion system (PrepStart – Danville Engineering) set at 80 psi, 90o tip angle, 0.48 inner diameter tip and 50um particle size. In each group, in half of the specimens, phosphoric acid (10%) will applied during 15s. SEM analysis (500 and 2000 x) will be performed by two calibrated examiners and classified in scores: 0 = no smear layer and all dentin tubes opened; 1 = minimal amount of smear layer and more than 50% of the tubes opened; 2 = moderate amount of smear layer and less than 50% of the tubes opened; 3 = thick smear layer and almost all tubes closed. The scores will be submitted to Kruskall-Wallis test at the significance level of p=0.05.