Abstract:

Transalveolar technique for sinus floor elevation（TSFE） offers the advantages of minimal invasiveness， reduced postoperative reaction， and shorter operative time for vertical bone augmentation in the maxillary posterior region. The clinical data of one patient with severe deficiency of residual bone height （RBH） in the maxillary posterior region， a blood vessel visible in the lateral wall of the maxillary sinus and a visible septum at the floor of the maxillary sinus were reported， and two-stage flexible TSFE was used to improve the vertical bone height of the operated area while reducing trauma， the risk of Schneiderian membrane rupture and maxillary sinus infection， etc.， and the relevant literatures were reviewed. The patient， male， 26 years old， complained of missing left maxillary posterior teeth for more than 1 year and requested restoration. The patient had 27 missing teeth， normal keratinized gingiva， full alveolar ridge， no elongation of the opposing teeth， fair width of the proximal and normal occlusal distance. The results of cone beam CT （CBCT） showed that the distance between the sinus crests at the site of the 27 teeth was about 3 mm， the width of the alveolar bone was about 12.8 mm， the bone density was normal， and there were no residual roots or other abnormalities； no cyst-like lesions were seen in the walls of the maxillary sinuses bilaterally， and separation was seen at the floor of the maxillary sinus on the left side and a blood vessel was seen in the lateral wall of the maxillary sinus. A diagnosis of Kennedy class Ⅱ maxillary tooth defects was made. After two stages of TSFE， the Schneiderian membrane was intact and the bone height of the implant area was elevated to 9.6 mm from 3 mm preoperatively after the completion of the restoration， with stable bone augmentation， good osseointegration，and restoration of normal occlusal function. For the patients with severe bone height deficiency in the maxillary posterior region， flexible two-stage TSFE should be considered， which can help to reduce the risk of maxillary sinus infection and Schneiderian membrane rupture while minimizing the damage and obtaining the ideal bone augmentation results.

Key words: Sinus floor elevation, Transalveolar technique for sinus floor elevation, Schneiderian membrane, Bone regeneration, Dental implantation, Platelet-rich fibrin