Accuracy analysis of alveolar dehiscence and fenestration of maxillary anterior teeth of Angle class III by cone-beam CT / 北京大学学报(医学版)

OBJECTIVE@#To evaluate the accuracy and reliability of detecting alveolar bone dehiscence and fenestration of maxillary anterior teeth of Angle class III by cone-beam computed tomography (CBCT).@*METHODS@#Eighteen Angle class III patients with 108 maxillary anterior teeth were included (3 males and 15 females) who accepted modified corticotomy in orthodontic therapy. The mean age was 23.6 years (18-30 years). The clinical detection of dehiscence and fenestration was done when modified corticotomy was performed by the same periodontist. The CBCT examination was conducted pre-operation and the detection of dehiscence and fenestration by CBCT was done by two periodontists. The data in modified corticotomy were used as the golden standard to calculate the parameters, such as sensitivity, specificity, positive and negative predictive values, Youden index (YI), positive and negative likelihood ratio. Kappa statistic was used to analyze the agreement between the clinical detection and the CBCT detection.@*RESULTS@#The incidence of dehiscence and fenestration was about 10.19% and 13.89% respectively, which mainly occurred on lateral incisors and canines. The median values of length and width of dehiscence were about 5 mm and 4 mm, and the median values of length and width of fenestration were 3 mm and 2 mm, respectively. Most fenestrations were detected on the middle third to the apical third of the root. For dehiscence, the agreement between clinical detection and CBCT detection was statistically significant (P<0.05). For fenestration, the agreement between clinical detection and CBCT detection was statistically significant (P<0.05). The values of sensitivity and specificity for detecting dehiscence were more than 0.7. The values of positive and negative predictive values for detecting dehiscence were 0.44 and 0.97. The values of sensitivity and specificity for detecting fenestration were 0.93 and 0.52. The values of positive and negative predictive values for detecting fenestration were 0.24 and 0.98.@*CONCLUSION@#For dehiscence, the agreement between clinical detection and CBCT detection was good. For fenestration, the agreement between clinical detection and CBCT detection was general. Detection of dehiscence and fenestration of maxillary anterior teeth of Angle class III by CBCT had limited diagnostic value in clinical practice with overestimation of dehiscence and fenestration incidence.

Morphological analysis of alveolar bone of anterior mandible in high-angle skeletal class II and class III malocclusions assessed with cone-beam computed tomography / 北京大学学报(医学版)

OBJECTIVE@#To evaluate the difference of features of alveolar bone support under lower anterior teeth between high-angle adults with skeletal class II malocclusions and high-angle adults presenting skeletal class III malocclusions by using cone-beam computed tomography (CBCT).@*METHODS@#Patients who had taken the images of CBCT were selected from the Peking University School and Hospital of Stomatology between October 2015 and August 2017. The CBCT archives from 62 high-angle adult cases without orthodontic treatment were divided into two groups based on their sagittal jaw relationships: skeletal class II and skeletal class III. vertical bone level (VBL), alveolar bone area (ABA), and the width of alveolar bone were measured respectively at the 2 mm, 4 mm, 6 mm below the cemento-enamel junction (CEJ) level and at the apical level. After that, independent samples t-tests were conducted for statistical comparisons.@*RESULTS@#The ABA of the mandibular alveolar bone in the area of lower anterior teeth was significantly thinner in the patients of skeletal class III than those of skeletal class II, especially in terms of the apical ABA, total ABA on the labial and lingual sides and the ABA at 6 mm below CEJ level on the lingual side (P<0.05). The thickness of the alveolar bone of mandibular anterior teeth was significantly thinner in the subjects of skeletal class III than those of skeletal class II, especially regarding the apical level on the labial and lingual side and at the level of 4 mm, 6 mm below CEJ level on the lingual side (P<0.05).@*CONCLUSION@#The ABA and the thickness of the alveolar bone of mandibular anterior teeth were significantly thinner in the group of skeletal class III adult patients with high-angle when compared with the sample of high-angle skeletal class II adult cases. We recommend orthodontists to be more cautious in treatment of high-angle skeletal class III patients, especially pay attention to control the torque of lower anterior teeth during forward and backward movement, in case that the apical root might be absorbed or fenestration happen in the area of lower anterior teeth.

Class III surgical patients facilitated by accelerated osteogenic orthodontic treatment / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the treatment time and the anterior and posterior teeth movement pattern as closing extraction space for the Class III surgical patients facilitated by accelerated osteogenic orthodontic treatment.</p><p><b>METHODS</b>There were 10 skeletal Class III patients in accelerated osteogenic orthodontic group (AOO) and 10 patients in control group. Upper first premolars were extracted in all patients. After leveling and alignment (T2), corticotomy was performed in the area of maxillary anterior teeth to accelerate space closing.Study models of upper dentition were taken before orthodontic treatment (T1) and after space closing (T3). All the casts were laser scanned, and the distances of the movement of incisors and molars were digitally measured. The distances of tooth movement in two groups were recorded and analyzed.</p><p><b>RESULTS</b>The alignment time between two groups was not statistically significant. The treatment time in AOO group from T2 to T3 was less than that in the control group (less than 9.1 ± 4.1 months). The treatment time in AOO group from T1 to T3 was less than that in the control group (less than 6.3 ± 4.8 months), and the differences were significant (P < 0.01). Average distances of upper incisor movement (D1) in AOO group and control group were (2.89 ± 1.48) and (3.10 ± 0.95) mm, respectively. Average distances of upper first molar movement (D2) in AOO group and control group were (2.17 ± 1.13) and (2.45 ± 1.04) mm, respectively.No statistically significant difference was found between the two groups (P > 0.05).</p><p><b>CONCLUSIONS</b>Accelerated osteogenic orthodontic treatment could accelerate space closing in Class III surgical patients and shorten preoperative orthodontic time. There were no influence on the movement pattern of anterior and posterior teeth during pre-surgical orthodontic treatment.</p>

MESH diagrams of Chinese in Beijing and its preliminary application in practice / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To establish the normal MESH diagrams of Chinese in Beijing, and to build a computerized MESH analysis system for orthodontic practice.</p><p><b>METHODS</b>Twenty-eight subjects with normal occlusion were selected in Beijing and their lateral cephalograms were taken at the age of thirteen and eighteen, respectively. Individual MESH diagrams were then established for each subject mainly according to Moorrees' method from the cephalograms orientated in estimated natural head position. Male and female normal MESH diagrams were created. A computerized MESH analysis system was also developed.</p><p><b>RESULTS</b>The normal MESH diagrams of Chinese in Beijing, thirteen and eighteen years old respective, were established. The computerized MESH analysis system was constructed and used in orthodontic patients.</p><p><b>CONCLUSIONS</b>MESH analysis is a proportional analysis method. It can show the results directly, succinctly and holistically. It is also a favorable complement and amendment to the commonly used angle and linear X-ray analysis methods.</p>