ABSTRACT
Objective To investigate labial and lingual alveolar bone plate thickness of the mandibular anterior teeth by using cone-beam computed tomography (CBCT),in order to provide a reference for immediate implantation.Methods 132 individuals with normal occlusion were examined with CBCT,and their mandibular anterior teeth were analyzed.The labial and lingual alveolar bone plate thickness at the level of the apical,1/4 of the apical,1/2 of the middle and 1/4 of the cervical were measured.The differences of the thickness were compared among the side and gender.Results There were no significant differences between the left and right sides. Except on the 1/4 of the cervical,the thickness of lingual bone plate was thicker than that of labial bone plate.The frequency of the thickness of the labial bone larger than 2 mm on the 1/4 of the cervical of the center incisor,lateral incisor,and canine were 0,0 and 1.5 1%,respectively,and on 1/4 of the middle were 0.76%,1.44% and 3.79%,respectively.The lingual bone plate thickness showed significant difference between genders.Conclusion Reference values of alveolar bone plate thickness in anterior teeth of normal occlusion were established by using CBCT,which can provide clinical instruction for immediate implant.
ABSTRACT
The number of root canals varies most in the areas of mandibular anterior teeth, maxillary and mandibular premolars, and premolars. Generally, The mandibular anterior teeth have one root canal, but data suggest that the anatomical morphology of the root canals of mandibular incisors varies greatly, which easily leads to the neglect of root canals in endodontic treatment. This report described the case of a mother and a daughter whose mandibular anterior teeth have two symmetrical root canals.
ABSTRACT
Straight access cavity design allows the operator to locate all canals, helps in proper cleaning and shaping, ultimately facilitates the obturation of the canal system. However, change in the fracture strength according to the access cavity designs was not clearly demonstrated yet. The purpose of this study was to determine the influence of different access cavity designs on the fracture strength in endodontically treated mandibular anterior teeth. Recently extracted mandibular anterior teeth that have no caries, cervical abrasion, and fracture were divided into three groups (Group 1 : conventional lingual access cavity, Group 2 : straight access cavity, Group 3 : extended straight access cavity) according to the cavity designs. After conventional endodontic treatment, cavities were filled with resin core material. Compressive loads parallel to the long axis of the teeth were applied at a crosshead speed of 2mm/min until the fracture occurred. The fracture strength analyzed with ANOVA and the Scheffe test at the 95% confidence level. The results of this study were as follows : 1. The mean fracture strength decrease in following sequence Group 1 (558.90 +/- 77.40 N), Group 2 (494.07 +/- 123.98 N) and Group 3 (267.33 +/- 27.02 N). 2. There was significant difference between Group 3 and other groups (P = 0.00). Considering advantage of direct access to apical third and results of this study, straight access cavity is recommended for access cavity form of the mandibular anterior teeth.