Research progress and application of rodents model construction of peri-implantitis / 口腔医学

@#With the increasing popularity of dental implants, prevalence of peri-implantitishas also been increasing in recent years. However, a deeper understanding of the pathogenesis of peri-implantitis is still lacking. Animal models are a good bridge for studying the pathogenesis of clinical diseases. Animals such as mini-pigs, canines, non-human primates and rodents are used to construct animal models of peri-implantitis. Among them, rodents are easy to obtain and feed, and have a wide range of applications for research. In this review, we summarize the construction of rodent modelswithperi-implantitis as well as the research progress and applications.

Research progress on selective tooth agenesis caused by LRP6 gene mutation / 口腔疾病防治

@#Selective tooth agenesis (STA) is an abnormal number of teeth due to genetic factors or the environment and is most commonly observed for permanent teeth. LRP6 is one of the common causative genes of STA and is inherited by an autosomal dominant mechanism, leading to non-syndrome tooth agenesis (NSTA) or syndrome tooth agenesis (STA). NSTA is only involved in tooth number and appearance abnormalities, whereas STA caused by LRP6 gene mutation results abnormal ear development, oral-facial clefting, sparse hair and hypohidrosis. In this paper, we review the phenotype and gene mutation traits of selective STA caused by LRP6 gene mutation identified in recent years and describe 38 patients with tooth agenesis from 24 mutation sites of LRP6 gene. We analyzed the percentage of missing teeth and found that the lateral incisor in the maxilla and the second premolar in the maxilla and mandible were most commonly lost, whereas all central incisors in the maxilla remained. LRP6 gene plays a major role in tooth development via the WNT/β-catenin signaling pathway, and LRP6 gene mutation can lead to a series of abnormal manifestations due to the disruption of the signaling pathway. The literature showed that LRP6 gene mutations occurred mostly at the E1 or E2 subdomain, meaning that STA due to the mutants extracellularly disturbed the WNT/β-catenin signaling pathway. However, mature treatments for selective congenital tooth loss are lacking.

Preliminary study of familial nonsyndromic tooth agenesis caused by ectodysplasin A mutation / 口腔疾病防治

Objective@# To explore the pathogenic genes in a Chinese family affected by nonsyndromic tooth agenesis so as to study the pathogenesis of oligodontia.@*Methods @# Hospital ethical approval and informed consent of the patients and family members were obtained. Clinical data of the proband and close family members were collected, peripheral venous blood was collected, and DNA was extracted. Gene sequencing was performed through whole-exome sequencing, and then the screened pathogenic genes were verified by Sanger sequencing. The three-dimensional structure of the mutant proteins was analyzed and compared with the wild-type using bioinformatics tools.@*Results@#The two patients with congenital majority tooth loss in this family were cousins, and there were no other patients with congenital majority tooth loss in the family. Besides congenital multiple tooth loss, the two patients had no obvious hair abnormalities, finger/toe abnormalities, sweating abnormalities or other abnormal manifestations of ectodermal tissue. We found a mutant gene that in this family by carrying out gene sequencing of the patients and their close family members. A novel EDA (ectodysplasin A) missense mutation c.983C>T (p. Pro328Leu) was identified, which changed the encoded amino acid from proline (Pro) to leucine (Leu). Analysis of the mutation site showed that the site was highly conserved, and three-dimensional structure modeling also found that it changed the structure of EDA. @* Conclusion@#A novel EDA missense variant (c.983C>T, p.Pro328Leu) was first identified in a Chinese family with nonsyndromic tooth agenesis, extending the mutation spectrum of the EDA gene.

Novel mutations identified in the WNT10A gene and implant rehabilitation of patients with severe tooth agenesis / 口腔疾病防治

Objective@#To detect WNT10A gene mutations in patients with oligodontia or anodontia (≥6 teeth missing) and analyze their dental phenotype. @*Methods@#Patients with oligodontia or anodontia were enrolled from the clinic for oral examination, genetic history collection and whole exon sequencing, and patients with WNT10A gene mutations were included. Sanger sequencing was utilized to validate the WNT10A gene variations in probands and family members compared with the normal sequence. The pathogenicity of WNT10A mutations was evaluated by functional prediction, conservation analysis and structure prediction of protein mutants. Implant rehabilitation was applied to restore the patients' oral function.@*Results@# Five WNT10A gene mutations were detected in six unrelated patients, and c.26G>A (p. Trp9X) and c.1036delT (p. Cys346fs) were novel mutations with pathogenic potential. The mean number of missing teeth was (15.33±8.64) per case. The most frequently missing permanent teeth were maxillary canines (100%), and the least frequently missing teeth were mandibular first molars (25%). Implant rehabilitation was applied in five patients, and patients were found to have ideal implant osseointegration and functional restoration.@*Conclusion @# This study identified novel WNT10A gene pathogenic variants, enriching the WNT10A gene spectrum and providing new evidence for genetic diagnosis and prenatal consultation. Implant rehabilitation was also proven to be a treatment option for these patients.

Clinical evaluation of implant-supported prostheses for edentulous patients with ectodermal dysplasia / 口腔疾病防治

Objective@#The aim of the present study was to evaluate the clinical outcomes of implant-supported prostheses for oral function rehabilitation in patients with ectodermal dysplasia.@*Methods @#Thirteen patients were included in the present study. After bone augmentation, zygomatic implants (ZIs) or regular implants (RIs) were placed, fabrication of dental prostheses were applied, and psychological and oral education was carried out. Implant survival rates, patient satisfaction and other related evaluation indicators were assessed. @*Results@#The ilium was chosen for autogenic bone grafts in two patients. The fibula was used in two other patients and the mandibular ramus in one other patient. One patient was treated through alveolar distraction osteogenesis of the mandible. Guided bone regeneration was applied in seven other patients. Bone graft resorption in the maxilla was observed in one patient; bone augmentation of the mandible was successful in all patients, and no obvious bone resorption was observed. One hundred and eighteen implants were placed, among which 22 were ZIs, and 96 were RIs. Five RIs failed and were removed. The survival rate for ZIs was 100%, and the survival rate for RIs was 94.79%, in a follow up after 3 years. All patients were satisfied with the restoration of their oral function. More than 50% of the patients exhibited self-confidence.@*Conclusion@# Oral function can be restored in edentulous ectodermal dysplasia patients using bone augmentation and implant-supported prostheses, and patient self-confidence can be enhanced. However, the resorption of grafted bone in the anterior region of the maxilla cannot be ignored.

The application and development of dynamic navigation system in implant dentistry / 口腔疾病防治

@#Dynamic surgical navigation system has been wildly used in implantology, the navigation surgical system provide preoperative trajectory planning. Moreover, the constant visualization of drilling trajectory during operation assist the operators by avoiding critical anatomic structures to achieve safer surgery. Our article focuses on the development and function of dynamic navigation system to evaluate the accuracy of dynamic surgical navigation system when used for regular implants and zygomatic implants placement. We aim to discuss the accuracy of different brand of dynamic surgical navigation systems for implants placement and to investigate the main reasons led the inaccurate outcome.