Bacteria play a major role in the etiology of apical periodontitis. Traditionally it has been held the microorganisms are present in necrotic tissue in the root canal system and in tubules of the root dentin whereas the periapical tissues are free of bacteria. However, it is reported the presence of bacterial in the periapical lesions. They may form the biofilm and survive in the periapical tissues. Especially high incidence of biofilm is reported in the refractory periapical lesions. treatment was presented in the left maxillary first premolar with a long-standing fistula and apical calculus. Also. the role of biofilm and its treatment were discussed.

Euccal fat pad is special fat tissue which is different from subdermal fat. Anatomically, buccal fat pad is easy to harvest in the course of dental surgery procedure. In 1802, it was introduced by Bichat, Since Egyedi used buccal fat pad flap for the closure of oro-antral fistula and oro-nasal fistula, it has been widely used as an alternative method for the reconstruction of small to medium-sized intraoral defects in oral and mzxillofacial surgery. Kim et al. reported successful results in the all cases they applied buccal fat pad for the reconstruction of intraoral defect from their 31 months follow-up data. Because intraonal wounds are difficult to complete the layered suture and there are high risks of infection related with wound dental implant surgery, double layer closure using some kind of local flaps or other procedure is recommended. So we are to introduce the useful applications of the pedicled buccal fat pad in the dental surgery procedure from the various case presentations.