No abstract

The pulp chamber volume of the maxillary second molars has the largest correlation coefficient with age. Using multiple types of tooth may improve the accuracy of age estimation compared with only one type of tooth used.

Objectives: In contrast to two-dimensional planar images, a measuring point is hardly repeatedly determined in a CBCT image when alveolar bone loss is assessed. Thus, the aim of the present study was to propose a six-site measuring method, which is closely related to anatomical structure, for the evaluation of alveolar bone loss in CBCT images. Methods: 150 measuring points in 11 molars and 14 premolars from 6 patients (2 males and 4 females) were included. CBCT images of the teeth were acquired prior to periodontal surgery. Four observers measured the distances between cemento-enamel junctions and the apical bases of the periodontal bone defect at the mesio-buccal, mid-buccal, disto-buccal, mesio-lingual/palatal, mid-lingual/palatal and disto-lingual/palatal sites in CBCT images. Direct measurements of the six sites were correspondingly obtained in the subsequent periodontal surgeries. Differences between the distances measured in the CBCT images and during the surgery were analysed. Interobserver and intraobserver variances were tested. Results: No statistically significant difference was found between the surgical and CBCT measurements (p 5 0.84). Diagnostic coincidence rates of four observers were 86.7%, 87.3%, 88.7% and 88.0%, respectively. The interobserver (p 5 0.95) and intraobserver (p 5 0.30) variances were not significant. Conclusions: The six-site measuring method validated in the present study may be a useful three-dimensional measuring method for the evaluation of periodontal disease.

The aim of this review was to evaluate whether CBCT is reliable for the detection of root fractures in teeth without root fillings, and whether the voxel size has an impact on diagnostic accuracy. The studies published in PubMed, Web of Science, ScienceDirect, Cochrane Library, Embase, Scopus, CNKI and Wanfang up to May 2014 were the data source. Studies on nonroot filled teeth with the i-CAT (n = 8) and 3D Accuitomo CBCT (n = 5) units were eventually selected. In the studies on i-CAT, the pooled sensitivity was 0.83 and the pooled specificity was 0.91; in the 3D Accuitomo studies, the pooled sensitivity was 0.95 and pooled specificity was 0.96. The i-CAT group comprised 5 voxel size subgroups and the 3D Accuitomo group contained 2 subgroups. For the i-CAT group, there was a significant difference amongst the five subgroups (0.125, 0.2, 0.25, 0.3 and 0.4 mm; P = 0.000). Pairwise comparison revealed that 0.125 mm voxel subgroup was significantly different from those of 0.2, 0.25 and 0.3 mm voxel subgroups, but not from the 0.4 mm voxel subgroup. There were no significant differences amongst any other two subgroups (by α' = 0.005). No significant difference was found between 0.08 mm and 0.125 mm voxel subgroups (P = 0.320) for the 3D Accuitomo group. The present review confirms the detection accuracy of root fractures in CBCT images, but does not support the concept that voxel size may play a role in improving the detection accuracy of root fractures in nonroot filled teeth.

No abstract

The aim of this study was to explore the root morphology and root canal configuration of first premolars among Shandong Chinese residents using cone-beam computed tomography (CBCT). Randomly selected CBCT images were collected from 648 patients (44% women, 56% men). In total, 1268 maxillary and 1296 mandibular first premolars were analyzed. The number of roots and the canal configuration were recorded and identified based on Vertucci's classification. The majority of the maxillary first premolars had 1 root (67.4%), followed by 2 roots (32%). A 2-canal configuration (89%) was the most prevalent observation. For mandibular first premolars, 98.8% had 1 root and 81% presented the type I configuration. There were no statistical differences in the number of roots or morphology in terms of the left/right side or sex (P > .05). Among Chinese residents, the majority of maxillary first premolars had 1 root and 2 canals, whereas the most common anatomical configuration for mandibular first premolars was 1 root with 1 canal.

The proposed method can extract tooth pulp cavity regions from teeth efficiently. The segmentation results of this method are more accurate compared to other popular methods under different circumstances and can be used for subsequent applications.

Objective: To train a U-Net model to segment the intact pulp cavity of first molars and establish a reliable mathematical model for age estimation. Methods: We trained a U-Net model by 20 sets of cone-beam CT images and this model was able to segment the intact pulp cavity of first molars. Utilizing this model, 239 maxillary first molars and 234 mandibular first molars from 142 males and 135 females aged 15–69 years old were segmented and the intact pulp cavity volumes were calculated, followed by logarithmic regression analysis to establish the mathematical model with age as the dependent variable and pulp cavity volume as the independent variable. Another 256 first molars were collected to estimate ages with the established model. Mean absolute error and root mean square error between the actual and the estimated ages were used to assess the precision and accuracy of the model. Results: The dice similarity coefficient of the U-Net model was 95.6%. The established age estimation model was [Formula: see text] (V is the intact pulp cavity volume of the first molars). The coefficient of determination (R2), mean absolute error and root mean square error were 0.662, 6.72 years, and 8.26 years, respectively. Conclusion: The trained U-Net model can accurately segment pulp cavity of the first molars from three-dimensional cone-beam CT images. The segmented pulp cavity volumes could be used to estimate the human ages with reasonable precision and accuracy.