Chinese Journal of Dental Research, 04/2015

Stem cells are unspecialised cells that can divide, renew, and differentiate into more specialised cells. Due to their unique properties, stem cells are known for their use in therapies and treatments for missing tissues and damaged parts of the body. However, due to the invasive nature and other ethical issues with the retrieval process and usage of stem cells, stem cells are clinically being used in a limited manner. Furthermore, due to the invasive nature of the retrieval process elsewhere, dental tissues are one of the most preferred sources for stem cells. This review covers all of the characteristics of dental tissue-derived stem cells and their potential future uses. Keywords: application, dental stem cell, mesenchymal stem cell, regeneration

Root canal therapy is currently the main method to treat pulpal and periapical diseases. Root canal therapy consists of a series of complex procedures, requires specific equipments, instruments and materials, and should be performed by qualified stomatologists (clinicians). Complicated cases should be referred to endodontic specialists or the clinicians trained by intense endodontic courses. In 2004, the Society of Cariology and Endodontology of Chinese Stomatological Association (CSA) published the 'Practices and evaluation criteria of root canal therapy (Discussion Version)'. Since then, opinions and comments regarding the 'Discussion Version' have been widely circulated within the society. The final version of the guideline was based on systematic reviews of scientific literature and requirements for the edit of technical guidelines, through several rounds of discussions, revisions and supplements. The society recommends this guideline for stomatologists (clinicians) to use during endodontic treatment.

Direct adhesive composite restoration, a technique to restore tooth defects by bonding composite resin materials, has been widely used in the restoration of dental caries or other tooth defects. Retention of composite resin restoration mainly relies on bonding strength between the materials and dental tissue. The clinical outcomes rely greatly on the regulated clinical practice of dentists. In 2011, the Society of Cariology and Endodontology of Chinese Stomatological Association (CSA) published the 'Practices and evaluation criteria of composite resin bonded restoration (Discussion Version)'. Since then, opinions and comments regarding the 'Discussion Version' have been widely circulated within the Society. The final version of the guideline was based on systematic reviews of scientific literature and requirements for the edit of technical guidelines, and through several rounds of discussions, revisions and supplements. The society recommends this guideline for clinicians to use in their practices, when conducting direct composite restorations.

Objective: To describe a technique for socket augmentation in molar extraction sockets with severe bone wall defect. Methods: Five teeth in four patients were included in this study. Each tooth had buccal and/ or lingual bone loss identified by bone sounding and periapical radiographs before removal. After a flapless, minimally invasive tooth extraction, the socket was grafted with deproteinized bovine bone mineral with or without a collagen membrane. At the buccal and/or lingual bone defect area, the buccal and/or lingual gingival walls may act as holders, to support the materials. Finally, colloidal silver gelatin sponge was packed gently on top of the graft or membrane to avoid graft or membrane exposure, without attempting to achieve primary closure of the soft tissue. Six months after augmentation, changes in ridge width, ridge height and keratinised tissue were measured on clinical photographs or radiographs. Results: The alveolar bone widths observed at implant surgery were all greater than 6 mm. All patients showed bone augmentation in terms of ridge height. Keratinised tissue width showed increased or minor reductions. Conclusion: Treated with this technique, the deficient socket was re-established in the molar area. Clinically, the quantity and quality of the bone obtained in the grafted sockets allowed for successful implant placement. Keywords: flapless surgery, gelatin sponge, molar teeth, severe bone wall defect, socket augmentation

Objective: To describe the simultaneous occurence of an autosomal dominant inherited MSX1 mutation and an X-linked recessive inherited EDA mutation in one Chinese family with nonsyndromic oligodontia. Methods: Clinical data of characteristics of tooth agenesis were collected. MSX1 and EDA gene mutations were detected in a Chinese family of non-syndromic oligodontia. Results: Mild hypodontia in the parents and severe oligodontia in the son was recorded. A novel missense heterozygous mutation c.517C>A (p.Arg173Ser) was detected in the MSX1 gene in the boy and the father. A homozygous missense mutation c.1001G>A (p.Arg334His) was detected in the EDA gene in the boy and the same mutant occurred heterozygously in the mother. Conclusion: Simultaneous occurence of two different gene mutations with different inheritence patterns, which both caused oligodontia, which occurred in one subject and in one family, was reported. Keywords: EDA, inheritance, MSX1, mutation, oligodontia

Objectives: To investigate the stain removal ability of melamine sponge before aesthetic tooth whitening in extracted teeth. Methods: Melamine sponge of thickness 40 mm was compressed and the destruction of the partition wall structure during the compression process was examined under a stereoscopic microscope. An extracted human tooth was cleaned by normal polishing or with melamine sponge for 90 s. To evaluate the stain level, the tooth surfaces were photographed under a stereoscopic microscope at 0, 30, 60 and 90 s. The residual stained region was traced in a high-magnification photograph, and the stain intensity was presented as a change, relative to the intensity before the experiment (0 s). Results: Mechanical cleaning by toothbrushing produced polishing scratches on the tooth surface, whereas use of the melamine sponge resulted in only minimal scratches. As the compression level increased, the stain-removing effect tended to become stronger. Conclusion: Melamine sponge can remove stains from the tooth surface more effectively and less invasively compared to a conventional toothbrush. As no new scratches are made on the tooth surface when using a melamine sponge brush, the risk of re-staining is reduced. Cleaning using a melamine sponge brush can be easily and effectively performed at home and in a dental office. Keywords: melamine sponge, stain removing, toothbrush, tooth surface

Numerous techniques are described for lateral sinus augmentation, in order to expand bone volume, either by a crestal or lateral approach. A successful surgical procedure is determined by a number of factors. It is reported that different techniques for sinus augmentation have a high percentage of success, but presents a number of intraoperative and postoperative complications such as the Schneiderian membrane perforation and a long operating time. To manage the problem of the insufficient bone height in the posterior maxilla, various bonegrafting materials were applied using different techniques and instruments to elevate the sinus membrane and fill the subsinus cavity thereafter. The article aimed to describe a minimally invasive technique, using a special design bur to wear out the lateral bone safely and elevate the sinus membrane with sophisticated separators. Platelet-rich fibrin (PRF) and decalcified bone allograft was used as grafting material to enhance bone healing. This new technique for the sinus lateral wall osteotomy minimised the incidence of intraoperative and postoperative complications and the mixed use of PRF with decalcified bone allograft showing a satisficatory efficacy. Keywords: decalcified bone allograft, implant, lateral sinus augmentation, minimally invasive, platelet-rich fibrin