Procedure: - Apical Flap Repositioning - Trisection of the Upper Molar - Extraction of the Distobuccal Root - Tangential Preparation of the Abutment Teeth - Temporary Relining Contents: Molars with furcation involvement have a shorter long-term prognosis for tooth retention than single-rooted teeth. Apart from replacing these teeth with implants, they can also be treated by hemisection or trisection with the goal of eliminating furcation and creating single-root conditions. Studies on the long-term stability of teeth treated by hemisection / trisection show mixed results. Some investigators have found failure rates of up to 40 percent. In Gianfranco Carnevale's group, on the other hand, success rates of more than 90 percent have been reported for a 10-year follow-up period. Pretreatment: Initial work on the abutment teeth, which had grade II-III furcation involvement, was done six to eight weeks after conservative periodontal therapy in preparation for placement of the long-term temporary. Preparation was done tangentially, up to the bone level, to spare as much dental hard tissue as possible while eliminating all recesses and root concavities. A metal-reinforced long-term temporary was used to splint the prepared teeth. Endodontic treatment of the affected teeth was subsequently performed. Surgical procedure: Apical displacement of the gingiva around the involved teeth was done before incision. A mucosal fl ap was created on the buccal and palatal sides. Trisection of the teeth was then performed. After dissecting and excising the distobuccal root, intraoperative preparation of the abutment teeth was carried out. Temporary relining was another important step, the objective of which was to splint the root and to prevent tilting. Further treatment: Impressions for the defi nitive restoration were made six months postoperative. The restoration margins of the tangential preparation were defined using a master model. The definitive reconstruction had fine metal margins.