교합면 열구 법랑질의 미세구조 및 산부식 형태

Abstract

Ultra-structure and acid etching characteristics of occlusal fissure enamel

Cho, Tae-Sik D.D.S., M.S.D. Advisor : Prof. Lee, Sang-ho, D.D.S., M.S.D., Ph. D. Department of Dentistry Graduate school of Chosun University.

The purpose of this study was to compare the effectiveness of mechanical and acid treatment on enamel surfaces for the retention of pit and fissure sealants and evaluate the presence of a prismless layer. The etch pattern produced on enamel from immature and mature premolar teeth extracted with varying period of acid etching using 37% phosphoric acid was examined using a scanning electron microscope(SEM). The composition of each groups was evaluated using an energy dispersive x-ray(EDX) spectroscopy. The result of present study can be summarized as follows:

1. Prismless layer was commonly observed on the fissure enamel in young and mature premolar.

2. There were no differences in micro-structure and etching pattern on fissure enamel between the young and the mature premolar.

3. The most effective etching pattern for retention of pit and fissure sealant was observed in 60 seconds of etching time and no apparent difference of etching pattern was found among 15, 30, and 45 seconds of etching time which showed non-retentive etching patterns.

4. The etching pattern obtained by grinding enamel surface with bur followed by 60 seconds of etching was similar to that of 60 seconds of etching without any pretreatment of fissure surface.

5. Type 2 etching pattern was commonly found on fissure enamel in both young and mature premolar.

6. The calcium content and P/Ca ratio in fissure enamel between the young and the mature premolar were significantly different(P<0.05). But content of calcium, phosphate and P/Ca ratio on various regions of fissure enamel in both young and mature premolar did not showed any difference.

Based on these results, prismless layer may negatively influence the retention of pit and fissure sealants. Therefore, the mechanical removal of the prismless layer by grinding prior to etching or by prolonged etching time of enamel within the fissure system should result in an improved bonding of a pit and fissure sealant.