Application of the plasmatrix in alveolar ridge preservation / 口腔疾病防治

@#After tooth extraction, significant absorption occurs in the soft and hard tissues of the alveolar ridge. The goal of alveolar ridge preservation is to maintain the volume and shape of the alveolar ridge's soft and hard tissues as much as possible so as to provide suitable conditions for implant placement. Currently, there are challenges in classifying the socket for alveolar ridge preservation, such as the difficulty in directly guiding the selection of graft materials and clinical procedures and the insufficient space for particle xenograft maintenance, resulting in poor bone regeneration. Plasmatrix is an autologous blood derivative that effectively enhances tissue regeneration. This article introduced the characteristics of soft and hard tissue defects after tooth extraction and the primary applications of plasmatrix for alveolar ridge preservation (liquid plasmatrix, solid plasmatrix membrane/plug, and plasmatrix bone blocks) as well as the proposed methods for the reclassification of sockets for alveolar ridge preservation based on soft and hard tissue defects at the extraction site to facilitate the creation of clinical recommendations. The proposed classifications are as follows: Class I, extraction socket without bone defect, with or without soft tissue defect; Class Ⅱ, extraction socket with bone defect, both sides with bone wall defect less than 50%, with or without soft tissue defect; Class Ⅲ, extraction socket with bone tissue defect, at least one side with bone wall defect greater than 50%, with or without soft tissue defect. For the Class I socket, a solid plasmatrix membrane or plug is inserted, followed by injection of liquid plasmatrix, using a double-layer solid plasmatrix membrane for socket closure; for the ClassⅡ socket, plasmatrix bone blocks are inserted, followed by injection of liquid plasmatrix and secondary solidification, using absorbable collagen membrane and double-layer solid plasmatrix membrane for socket closure; for the ClassⅢ socket, tenting screws are used to maintain height, followed by implantation of plasmatrix bone blocks, injection of liquid plasmatrix and secondary solidification, using absorbable collagen membrane and double-layer solid plasmatrix membrane for socket closure. The aim of this article is to provide comprehensive knowledge of plasmatrix for oral clinicians to serve as a reference to simplify the clinical decision-making process and procedures for alveolar ridge preservation.

A novel mutation in the WNT6 gene of congenital tooth agenesis / 口腔疾病防治

Objective @#This article explores the relationship between congenital tooth agenesis and related gene mutations, providing a reference for early diagnosis of the disease.@*Methods @# Clinical and radiographic examinations of a rare case of congenital tooth agenesis were conducted to evaluate the abnormal morphology and quantity of the teeth, as well as the overall health of the patient. Bidirectional sequencing of the PAX9 and MSX1 genes and whole-exome sequencing were conducted to identify potential genetic abnormalities. Sanger sequencing of the newly discovered mutation site was performed on the proband's son. Subsequently, the impacts of the mutations were evaluated through computational tools and a cell-based gene transfection assay. @*Results @#This is a rare case of tooth agenesis characterized by a congenitally missing first molar, a second molar with one single root and a supernumerary second premolar in the right mandibular dentition. The c.717 C>C/T in PAX9 is synonymous. The c.119C>G in MSX1 is a missense mutation predicted to be “benign” by Polyphen. Through whole-exome sequencing, we found a novel mutation, c.637-7 C>A in intron 3 of the WNT6 gene, which is predicted by MAXENT to influence the splicing of mRNA. Both the proband and his son carry this mutation. A cell-based gene transfection assay demonstrated that it did not alter the mRNA splicing of WNT6. @* Conclusion @#The interaction between single nucleotide polymorphisms may contribute to congenital tooth agenesis.

Osteogenic potential of recombinant human bone morphogenetic protein-2 combined with Bio-oss bone substitute in implant restorations in anterior esthetic region / 口腔疾病防治

Objective@#To study the osteogenic potential of recombinant human bone morphogenetic protein 2 (rhBMP-2) combined with Bio-oss bone substitute in the implant restoration of bone defects in the anterior esthetic region. @*Methods@# Twelve patients who underwent the immediate placement of 20 implants with a bone augmentation procedure using rhBMP-2 and Bio-oss were included in this study. Changes in the height and thickness of the buccal bone over 6 months were measured, and the soft tissue was evaluated using the pink esthetic score (PES) after crown placement. @*Results@# All 20 implants were successfully osseointegrated, and the average increase in bone height was 1.9 mm; different degrees of bone height growth were observed for 17 (85%) implants sites. In one case, there was a severe bone fracture on the buccal side before the operation, resulting in bone plate resorption and decreased alveolar bone height. The bone height did not change significantly in 2 cases. The thickness of the buccal bone plate for all implants was greater than 1 mm. The average thickness was 1.9 mm, and the average PES was 9.8 points. @*Conclusion@# rhBMP-2 combined with Bio-oss bone substitute has a preferable effect on the restoration of bone defects in the anterior esthetic area, and can achieve good aesthetic effect.