하악 대구치의 제 II형 근심 근관에서 치근단 부위의 만곡도 조사

Abstract

ABSTRACT An evaluation of canal curvature at merging point in Type II mesial canals of mandibular molars

Yun, Hye-Rim, D.D.S. Advisor : Prof. Hwang, Ho-Keel, D.D.S.,Ph.D. Department of Dentistry, Graduate School of Chosun University

Mesial canals of mandibular molars are usually narrow, with great apical curvatures predisposing to higher fracture frequency of Ni-Ti files. In addition, the mesial canals of mandibular molars coalesce to form one major foramen with abrupt angle. The purpose of this study was to evaluate the curvature of Vertucci's type II mesial canals of mandibular molar using new method; The radius and angle of curvature describe canal shape and geometry. Total 100 mandibular molar teeth were selected without making any age and sex discrimination. Following a standard endodontic access in the teeth, their distal roots were removed and #15 H- or K-files were introduced into the mesiobuccal and mesiolingual canals of the teeth. Radiographs of the teeth were taken in the bucco-lingual view and mesio-distal view. The digital images of radiographs were obtained and magnified at 8 times. Root canal were classified according to Vertucci's classification. In our study, we selected Vertucci's type II and devided two subgroup; IIa and IIb. Specimens of two subgroup were examined the radius of and angle of curvature. The results were statistically analyzed using ANOVA test at P=0.05 level.

The results were as follows:

1. 46% of mesial roots of mandibular molars were Type II (IIa:26%, IIb:20%). 2. There were no statistically significant differences in radius and angle of curvature between mesio-buccal canals and mesio-lingual canals in total samples of type II. 3. Radius of the curvature in type IIa were smaller than type IIb. 4. In type IIa, radius of the curvature of mesiolingual canals were significantly smaller than mesio-buccal canals(p<0.05).However,there were no significant differences in angle of curvature.

In conclusion, mesio-lingual canals of Vertucci's type IIa are more abrupt curvature in joining point. Therefore, clinician should be consider of this results during root canal instrumentation.