Objective:The aim of the present study is to assess the root and root canal morphology of maxillary and mandibular premolars in a Turkish population by using cone beam computed tomography (CBCT).Materials and Methods:In this study, CBCT images of 2134 premolars (987 maxillary, 1147 mandibular) were obtained from 404 patients. Details of gender, age, number of roots and canals, and canal configuration in each root were recorded. The canal configuration was classified and evaluated according to Vertucci's criteria.Results:The majority of maxillary premolars had two separate roots; although, three roots were identified in 1% of maxillary first premolars. However, most of the mandibular premolars had a single root. The two canals (69.9%) and type I (62.6%) and type II (34.1%) configuration for upper first premolar, one canal (82.1%) and type I (77.6%) canal configuration for second premolar was the most prevalent root canal frequency. The most prevalent root canal frequency was the one canal (96.2%) and type I (94.2%) and type V (3.2%) configuration for mandibular first premolar, one canal (98.9%) and type I (98.9%) canal configuration for second premolar. There was no difference in the root canal configurations and the numbers of canals between the left and the right side of both females and males (P > 0.05).Conclusions:Recognition of morphology and anatomy of the root canal system is one of the most important factors for successful endodontic treatment. Preoperative CBCT examination allows determination of root canal configuration of premolar teeth and helps clinicians in root canal treatment.

BackgroundThis study assessed the relationship between mucosal thickness (MT) of the maxillary sinus and periodontal bone loss (PBL) and periapical condition of related teeth. We also aimed to identify the association between root apices and the inferior wall of the maxillary sinus using Cone beam computed tomography (CBCT).Material and MethodsIn this study, CBCT images of 205 patients with 410 maxillary sinuses were examined, retrospectively. A total of 582 maxillary molars and 587 premolars were observed. The relationship of each root with maxillary sinus and apical lesions of these roots were classified, PBL was examined and the situations of adjacent teeth were estimated. The effect of these conditions on sinus mucosal thickness (MT) was evaluated.ResultsThere was a significant correlation between MT of maxillary sinus and both PBL and age (r = 0.52, p=0.000 and r = 0.111, p= 0.002, respectively). The frequency of MT increased as the severity of apical lesion enlarged. A positive correlation was found between MT and degree of PBL and periapical lesions. To reveal the association between MT and pulpoperiapical condition bivariate correlation was done and a significant relationship between the pulpoperiapical condition and MT was found (r = 0.17, p=0.000).ConclusionsThis retrospective study showed that MT of the maxillary sinus was common among patients with PBL and MT was significantly associated with PBL and apical lesions. The relationship of maxillary sinus to adjacent teeth had also positive correlation with MT. CBCT imaging enabled better evaluation of maxillary sinus, posterior teeth and surrounding structures compared to other imaging tools. Key words:Maxillary sinus mucosal thickness, apical periodontitis, periodontal bone loss, CBCT.

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Objective: This study aimed to examine the cone beam computed tomography (CBCT) images of impacted maxillary canines and mesiodentes. Methods: This retrospective radiographic study was performed on 177 patients with 200 impacted maxillary canines and 12 mesiodentes. Using CBCT images, the unilateral/bilateral occurrence, presence of root dilaceration, mesio-distal and buccopalatal location, impaction condition, contact region of adjacent teeth, presence and degree of root resorption of adjacent teeth, dental follicle width, closest distance to the nasal cavity, nasopalatinal canal, and maxillary sinus were assessed. For mesiodentes, the types, follicle width, direction, and relationship with anatomical structures were evaluated. Results: No statistical relationship was found between (buccopalatal and mesio-distal) position of canine and root resorption of adjacent teeth (p = 0.171). A negative correlation was observed between age and follicle width (r = −0.145, p = 0.048). No mesiodens with enlarged follicle and root resorption of adjacent teeth was found. Conclusion: Given the negative correlation between age and follicle width, older patients with impacted teeth can be followed up by two-dimensional radiographs unless periradicular radiolucencies are absent. Otherwise, CBCT evaluation is required for early detection of pathologies and prevention of possible surgical complications.

CBCT assessment of morphological features of the alveolar bone and locations of nerve canals and foramina in the anterior-premolar region of mandible represent useful practical anatomical information about the interforaminal region. This information is the guide to the dentist before implant surgery.