A split-mouth design study will be performed regarding the use of platelet concentrates on ridge preservation: L-PRF vs A-PRF vs control. Patient needing multiple teeth extractions in the upper jaw (single-rooted teeth) will be recruited. The use of each platelet concentrate or control will be randomized by means of a computer program. The results will be analysed clinical and radiographically (CBCT). When the subject will choose for implant rehabilitation, a biopsy will be taken in the site of the preserved sockets. The region will be localized with a customized stent, fabricated with the position of the extracted teeth. VAS scales will be provided to evaluate the post-operative discomfort.