The relationship between root concavities in first premolars and chronic periodontitis.

To evaluate the significance of first premolar root concavity on clinical indices of chronic periodontal disease and alveolar bone defects. Three-dimensional reconstruction by cone beam computed tomography was used to observe root surface anatomy and the type of alveolar bone defect seen in the mesial and distal sites of 272 first premolars from 99 patients who had presented with chronic periodontitis. Periodontal clinical indicators at each site were measured using a Florida Probe Corporation (Gainesville, FL, USA). The incidence of mesial and distal root concavities of the maxillary first premolars was 100% and 39.3% respectively, and in the mandibular, the incidence was 42.5% and 31.3% respectively. The distributions of the different types of concavities in terms of both age and gender of the patients were not statistically significant. The mean probing depth and clinical attachment loss of the first premolars with root concavities were significantly higher than those without concavity (p < 0.05). Plaque accumulation was significantly different in the premolars with/without root concavities (p < 0.001). The type of alveolar bone defects with concavities was significantly different from those without concavities (p < 0.05). Ramp shape bone defects were dominant for teeth without concavities, while crater shape was seen for teeth with concavities. Root concavities of the first premolars were associated with periodontal disease, and the type of interproximal alveolar bone defect. Root concavities may be important in contributing to local periodontal disease of the first premolars.

Zhao H ，Wang H ，Pan Y ，Pan C ，Jin X ... -  《-》

Three-dimensional measurement of bone loss at implants in patients with periodontal disease.

Kehl M ，Swierkot K ，Mengel R 《-》

A cone-beam computed tomography study of root canal morphology of maxillary and mandibular premolars in a Turkish population.

Ok E ，Altunsoy M ，Nur BG ，Aglarci OS ，Çolak M ，Güngör E ... -  《-》

Topographic analysis of maxillary premolars and molars and maxillary sinus using cone beam computed tomography.

Yoshimine S ，Nishihara K ，Nozoe E ，Yoshimine M ，Nakamura N ... -  《-》

A cone-beam computed tomography study of the mesial cervical concavity of maxillary first premolars.

To investigate the mesial cervical concavity of maxillary first premolars and its relationship with root and canal configuration using cone-beam computed tomography (CBCT). Images of maxillary first premolars (n = 1056) were collected from patients (n = 601) who had undergonein vivo CBCT scanning. The root and canal number and morphology were evaluated. The following measurements of the mesial cervical concavity of the maxillary first premolars were evaluated in section images: dentine thickness (in concavity at the cemento-enamel junction), concavity angle, depression depth (distance from mesial dentinal surface at concavity to mesial proximity), concavity position (distance from mesial dentinal wall at invagination to the top of the mesial marginal ridge). The reliability of the data was analyzed with an unpaired Student's t test and Fisher's exact test. The percentages of maxillary first premolars with one root, two, and three roots were 55.5%, 43.7%, and 0.8% respectively. Mesial cervical concavity was recorded in 64.5% of single-root maxillary premolars. The prevalence of two-root maxillary first premolars with mesial cervical concavity was 73.8%. The means of the aforementioned four measurements were 1.705, 147.9, 1.640, and 5.247 mm. The values of dentine thickness (mm), depression depth (mm), and concavity position (mm) of the mesial cervical concavity were largest in two-root maxillary first premolars. The smallest concavity angle of the mesial cervical concavity was found in three-root maxillary first premolars. There is a high prevalence of mesial cervical concavity among maxillary first premolars. The mesial root concavity is more prevalent in single-rooted maxillary first premolars when there are two canals present, and its prevalence and degree of concavity increase with the number of roots.

Fan L ，Yuan K ，Niu C ，Ma R ，Huang Z ... -  《-》