Whole exome sequencing and analysis of hypohidrotic ectodermal dysplasia patients / 中华口腔医学杂志

Objective: To detect gene mutation in patients with hypohidrotic ectodermal dysplasia (HED) by using whole exome sequencing, to analyze the pathogenicity of the mutations, and to provide reference for the genetic diagnosis of HED patients. Methods: Peripheral blood genomic DNA was extracted from each of the HED patients and their family members collected in Peking University School and Hospital of Stomatology from August 2016 to August 2021. Whole exome sequencing and sanger sequencing were performed to detect gene mutations. Functions of the rare variants after the database filtering were analyzed by bioinformatics tools. Results: Three reported mutations of ectodysplasin A (EDA) gene (c.2T>C, c.161A>G, c.467G>A) and a mutation of ectodysplasin A receptor (EDAR) gene (c.871G>A) were detected by whole genome sequencing in four HED patients, and were verified by Sanger sequencing in four HED families. The EDAR gene mutation founded in this research was reported in HED patients for the first time. Bioinformatics tools predicted that the mutations of EDA gene detected in this study were highly species conserved and disease-causing. The combined annotation dependent depletion (CADD) scores of EDA gene mutations c.2T>C, c.161A>G and c.467G>A were 22.5, 26.3 and 25.5 respectively, and the genomic evolutionary rate profiling (GERP) scores were 2.16, 2.26 and 2.18 respectively. The EDAR gene mutation c.871G>A detected in this study was species conserved and possibly disease-causing. The CADD and GERP scores of EDAR gene mutation c.871G>A were 22.0 and 1.93 respectively. Conclusions: Three reported mutations of EDA gene and a previously unreported mutation of EDAR gene were detected in four HED families. Different mutations of EDA gene and EDAR gene could make different influence on the protein function and lead to the occurrence of HED.

Clinical study on autologus platelet-rich fibrin aided revascularization of immature permanent teeth / 北京大学学报(医学版)

OBJECTIVE@#To compare the clinical treatment efficiency of platelet-rich fibrin (PRF) assisted revascularization and traditional revascularization in immature permanent teeth.@*METHODS@#Eighteen non-vital immature permanent teeth of sixteen patients which were diagnosed as necrotic pulpitis with (or without) periapical inflammations were treated with PRF assisted revascularization. Twenty-two teeth non-vital immature permanent teeth of twenty patients which were diagnosed as necrotic pulpitis with (or without) periapical inflammations were treated with traditional revascularization. All the cases were accorded with inclusive criteria and were treated at Pediatric Dentistry of Peking University School and Hospital of Stomatology. The cases were followed up clinically and radiographically at regular intervals. Clinical examinations and periapical radiographs were recorded and analyzed. Clinical success rate was evaluated based on the clinical and radiographic findings. The changes of root length, dentine wall thickness and apical foramen width of the teeth from the two groups were measured and compared according to the preoperative and by recalling the periapical radiographs.@*RESULTS@#The cases were followed up for 6-16 months. Clinically, totally 17 out of the 18 teeth in PRF group and 21 out of the 22 teeth in traditional group were asymptomatic with no sensitivity to percussion or palpation. PRF group tended to be more effective than traditional group clinically without significant differences (P=0.446). Radiographically, 15 out of the 18 teeth in PRF group and 15 out of the 22 teeth in traditional group displayed that the roots developed, showing that root length and dentine wall thickness increased and apical foramen closed. There was a marked difference in dentine wall thickening in PRF group in comparison with traditional group (P=0.039). However, the changes of root length increasing (P=0.411) and apical foramen width closure (P=0.737) were comparable in both groups. The result in electric pulp test (P=0.517), root canal calcification (P=0.324) and crown discolor (P=0.386) were also comparable in the two groups.@*CONCLUSION@#PRF assisted revascularization and traditional revascularization in non-vital immature permanent teeth which were diagnosed as necrotic pulpitis with (or without) periapical inflammations resulted in similar clinical outcomes. Both methods showed good prognosis. PRF revascularization seemed to have better effect on dentine wall thickening than traditional method.

Analysis of dental agenesis patterns of the oligodontia patients using the method of tooth agenesis code / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To analyze the common dental agenesis patterns of the oligodontia patients.</p><p><b>METHODS</b>The information of 64 oligodontia patients was collected, including the histories, oral examinations and panoramic radiographs. The Tooth Agenesis Code (TAC) procedure was used to analyze the agenesis pattern of each quadrant.</p><p><b>RESULTS</b>In the maxilla, 63% (40/64) (right side) and 58% (37/64) (left side) could be described using eight different patterns. The most common pattern was agenesis of the maxillary lateral incisor, canine and both premolars.In the mandible, 52% (33/64) (right side) and 53% (34/64) (left side) of the patients could be described using only five different patterns, the most common pattern was agenesis of both mandibular premolars.</p><p><b>CONCLUSIONS</b>Common patterns of tooth agenesis were successfully identified in non-syndromic oligodontia patients.</p>

Clinical analysis of simple hypodontia / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To compare and analyse the distribution and characteristic of born missing teeth.</p><p><b>METHODS</b>A total of 183 simple hypodontia patients was reviewed and statistically analysed.</p><p><b>RESULTS</b>There was no significant difference in the number of missing teeth between different sexs (P > 0.05), and there was also no significant difference in the number of missing teeth among different sites (maxilla, mandible or left and right sides) (P > 0.05). The mandibular second premolar was the most frequently missing tooth. The missing molars were more commonly seen in oligodontia patients who had six missing teeth or beyond than hypodontia patients with less than six missing teeth (P < 0.05).</p><p><b>CONCLUSIONS</b>Each hypodontia patient has his own clinical manifestation, and appropriate treatment should be planed accordingly for these patients.</p>

Clinical and experimental study on the reattachment of fractured anterior teeth / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the clinical results of three bonding patterns for the reattachment of anterior fractured teeth.</p><p><b>METHODS</b>The reattachment of 59 anterior fractured teeth was performed using three bonding patterns, which were pattern A (pulp chamber concave + labial chamfer), pattern B (pulp chamber concave + lingual notch) and pattern C (pulp chamber concave + lingual notch + labial chamfer), and followed up for more than 24 months. Pattern A, B and C were 14 teeth, 14 teeth and 31 teeth, respectively. Twenty-one sectioned maxillary central incisors (obtained from patients with periodontal disease) whose edge fragments reattached using the three bonding patterns were used for the experimental study of shear bond strength, and each pattern was used in 7 teeth.</p><p><b>RESULTS</b>Three reattached teeth fractured again due to another trauma, two of which was pattern B and one was pattern A. The reattachment of the remaining 56 anterior fractured teeth was successful after a follow up of mean 28.3 months. The experimental study showed that bonding pattern A and C could bear more shear stress than bonding pattern B (F = 5.161, P = 0.017).</p><p><b>CONCLUSIONS</b>The present study suggests that bonding pattern A (pulp chamber concave + labial chamfer) and C (pulp chamber concave + lingual notch + labial chamfer) were the best methods for the reattachment of fractured anterior teeth.</p>