关键词: 上颌磨牙, 重度牙周炎, 牙槽嵴保存, 牙种植

Abstract: The teeth with severe periodontitis are often accompanied by severe infection and alveolar bone defects，and further physiological absorption and remodeling of the alveolar ridge after tooth extraction，which will increase the difficulty in prosthetically driven implant placement. Especially，the maxillary molar region is close to the maxillary sinus，maxillary sinus floor elevation is usually required to compensate for insufficient vertical bone. This paper presents the clinical outcome of alveolar ridge preservation with flapless techniques in maxillary molar extrication sockets suffering from severe periodontitis. Atraumatic extraction and flapless techniques for alveolar ridge preservation were used to preserve the extraction socket，which effectively reduced bone absorption and achieved the preservation and reconstruction of alveolar ridge，providing a good three-dimensional condition of bone tissue for implant placement. This method advances the process of bone augmentation in the maxillary molar region and simplifies the complexity of implant treatment，which is worthy of clinical application.

Key words: maxillary molar, severe periodontitis, ridge preservation, dental implantation