• Restorative Dentistry and Endodontics
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• 제41권1호
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• pp.55-62
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• 2016

Objectives: The purpose of this study was to investigate the incidence of root fusion and C-shaped root canals in maxillary molars, and to classify the types of C-shaped canal by analyzing cone-beam computed tomography (CBCT) in a Korean population. Materials and Methods: Digitized CBCT images from 911 subjects were obtained in Chosun University Dental Hospital between February 2010 and July 2012 for orthodontic treatment. Among them, a total of selected 3,553 data of maxillary molars were analyzed retrospectively. Tomography sections in the axial, coronal, and sagittal planes were displayed by PiViewstar and Rapidia MPR software (Infinitt Co.). The incidence and types of root fusion and C-shaped root canals were evaluated and the incidence between the first and the second molar was compared using Chi-square test. Results: Root fusion was present in 3.2% of the first molars and 19.5% of the second molars, and fusion of mesiobuccal and palatal root was dominant. C-shaped root canals were present in 0.8% of the first molars and 2.7% of the second molars. The frequency of root fusion and C-shaped canal was significantly higher in the second molar than the first molar (p < 0.001). Conclusions: In a Korean population, maxillary molars showed total 11.3% of root fusion and 1.8% of C-shaped root canals. Furthermore, root fusion and C-shaped root canals were seen more frequently in the maxillary second molars.

• Imaging Science in Dentistry
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• 제47권3호
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• pp.157-164
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• 2017

Purpose: This study determined and compared the distances from the maxillary root apices of posterior teeth to the floor of the maxillary sinus, or maxillary sinus distances(MSDs), and the distances from the mandibular root apices of the posterior teeth to the mandibular canal, or mandibular canal distances(MCDs), in Thai subjects with skeletal open bite and skeletal normal bite. Materials and Methods: Pretreatment cone-beam computed tomography (CBCT) images were obtained from 30 Thai orthodontic patients (15 patients with skeletal normal bite and 15 with skeletal open bite) whose ages ranged from 14 to 28 years. The CBCT images of the patients were processed and measured using the Romexis Viewer program. The MSDs and MCDs from the root apices of the maxillary and mandibular second premolar, first molar, and second molar to the maxillary sinus floor or the mandibular canal were measured perpendicularly to the occlusal plane. The Student t test was used for comparisons between the 2 groups. Results: The greatest mean MSDs were from the root apex of the second premolars in both groups, whereas the least mean MSDs were from the mesiobuccal root apex of the second molars. The greatest mean MCDs were from the mesial root apex of the first molars, whereas the least mean MCDs were from the distal root apex of the second molars. Conclusion: There were no differences in the mean MSDs or the mean MCDs between the skeletal normal bite group and the skeletal open bite group.

• 대한소아치과학회지
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• 제47권1호
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• pp.25-35
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• 2020

이 연구의 목적은 CBCT를 사용하여 유구치 치근 및 근관의 형태학적 특징을 평가하는 것이다. 과잉치 발거를 위해 전남대학교 치과병원 소아치과에 내원하여 CBCT를 촬영한 만 4 - 5세 환자 총 68명의 영상으로 연구를 진행하였다. 치근 흡수가 되지 않은 상악 제1유구치, 상악 제2유구치, 하악 제1유구치, 하악 제2유구치로 구분하여 분석하였다. 치근 및 근관의 수, 치근 및 근관의 길이와 각도 등의 다양한 변수들이 분석되었다. 상악 유구치는 모두 3개의 치근을 가졌고 원심 협측 치근과 구개 치근은 단일 근관을 가졌다. 한 치근에 2개의 근관이 있는 경우는 오직 상악 제2유구치의 근심 협측 치근에서 발견되었다. 하악 유구치는 대부분 근심과 원심 2개의 치근을 가졌다. 하악의 근심 치근은 대부분 2개의 근관을 가졌다. 치근의 길이와 관련하여, 상악의 구개 치근의 길이가 가장 긴 반면, 원심 협측 치근의 길이는 가장 짧은 것으로 밝혀졌다. 하악 유구치는 근심의 치근이 더 길었다. 상악 유구치에서는 구개 치근의 각도가 가장 컸으나 하악은 근심의 각도가 더 작았다. 상악 유구치의 치근 및 근관이 곡선형이 많은 반면 하악 유구치는 직선형을 더 많이 볼 수 있었다.

• 구강회복응용과학지
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• 제22권2호
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• pp.173-180
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• 2006

Objectives The aim of this study is to compare the quality of root canal preparation completed using MFile-$System^{(R)}$ instrument ( Komet, Gebr.Brsaseler, Germany) and conventional stainless steel file in the canals of Maxillary molar teeth that had a canal curvature between $25^{\circ}$ or more Materials & Methods Buccal canals of 24 first and second maxillary molar teeth, extracted for periodontal and prosthetic reasons were used. Tissue fragments and calcified debris were removed from teeth by scaling and the teeth were stored in 10% formalin solution for 24 hour. Then, teeth were stored in saline until used. To be included the roots had to have completed formed apices and angle of curvature ranging between $25^{\circ}$ or more according to the criteria described by Schneider(1971). Palatal and Second mesiobuccal canals were not included. Teeth were embedded into transparent acrylic. The teeth were randomly divided into two experimental groups. All teeth were scanned by Dental CT (PSR9000N, Asahi, Japan) to determine the root canal shape before instrumentation. Image slices were prepared from the apical end point to the pulp chamber. The first two sections were 2 mm from the apical end of root and 2 mm below the orifice. Further section was recorded, dividing the distance between the sections of apical and coronal levels into two equal lengths. 12 teeth were instrumented using stainless steel fileand another 12 teeth were instrumented using MFile-$System^{(R)}$. Following the completion of the instrumentation, the teeth were again scanned and compared with the cross sectional images taken prior to canal preparation. Amount of transportation and centering ability was assessed. Student's t-test was used for statistical analysis. Result Less transportation occurred with MFile-$System^{(R)}$ rotary instrumentation than stainless steel instrument. MFile-$System^{(R)}$ had better centering ability than stainless steel instrument. Conclusion MFile-$System^{(R)}$ rotary instrumentation transported canals less and had good centering ability.