침식 법랑질의 표층은 건전 법랑질과는 물리화학적 성상이 다르므로 침식 법랑질면에 대한 복합레진의 결합력을 증가시키기 위한 대안으로, 법랑질 내층으로의 침투력이 탁월한 infiltrant resin을 응용하는 방법을 생각하게 되었다. 본 연구는 다양한 정도로 인공 침식이 유발된 법랑질면을 대상으로, infiltrant resin과/또는 기존의 접착제를 적용한 경우의 복합레진 결합강도를 비교 분석할 목적으로 시도되었다. 건전한 순면을 가진 발거된 상악 유전치를 대상으로, 인공침식 유발 횟수 및 infiltrant resin과/또는 기존의 접착제를 적용한 방법에 따라 각 20개씩의 시료를 제작하였으며, 각 군의 미세인장 결합강도를 측정하고, 파절면의 파절 양상을 평가하여 다음과 같은 결과를 얻었다. 법랑질 표면의 침식 유발 횟수가 늘어날수록 결합강도가 낮았다(p<0.05). 기존의 접착제 상부에 infiltrant resin을 추가 적용한 군, infiltrant resin만 적용한 군, 접착제만 적용한 군의 순으로 미세인장결합강도가 높게 나타났다(p<0.05). 파절 양상의 관찰에서는 인공 침식 유발 횟수가 적은 군 및 infiltrant resin을 적용한 군에서 응집파절의 비율이 높게 나타났다. 결론적으로, 법랑질의 침식도가 클수록 복합레진 수복물과의 결합 강도는 감소하였으며, infiltrant resin으로 기존의 적찹제를 대체하거나 첨가함으로써 결합강도를 보완시킬 수 있을 것으로 판단되었다.
Composite resin has been widely used for eroded enamel. But, as there have been many reports about the differences in physicochemical characteristics of eroded enamel compared with sound enamel, an additional effort was thought necessary to obtain the optimal bond strength. As a possible answer, we came to think about the application of infiltrant resin which is known to have an excellent penetration capacity into enamel. This study was performed for the purpose of comparing the bond strength of composite restoration with or without infiltrant resin under adhesives on the artificially eroded enamel. 60 extracted sound maxillary primary incisors were selected and divided into group 1, 2, 3 according to the number of artificial erosion cycling for 5 minute duration in 1% citric acid of pH 3.2 at $37^{circ}C$. And the labial surfaces were divided into 3 areas; group A, only resin adhesive was used, group I, only infiltrant resin, group IA, infiltrant resin followed by resin adhesive. Afterwards, every specimen was restored with composite resin. Microtensile bond strength was measured and failure modes were observed. The obtained results were as follows: 1. In comparing the bond strength by the degree of enamel erosion, it was revealed the highest bond strength in group 1, followed by group 2 and 3, showing the lowest bond strength in most eroded group(p<0.05). 2. In comparing the bond strength by surface treatment methods, group IA and I showed higher value than group A(p<0.05), with unsignificant difference between group I and IA(p>0.05). 3. In observation of failure mode, it was shown higher frequency of cohesive failure in order of 1-2-3 and IA-I-A. Conclusively, it was shown decreasing tendency of bond strength as the enamel is more eroded, and infiltrant resin was thought helpful to replace or add to the resin adhesive for optimal bonding with eroded enamel.
