Objective: The study investigated the impacts of third molar (M3) extraction on periodontal status of adjacent second molar (M2) and oral health-related Quality of life (QoL). Methods: 272 cases with M3 were randomly divided into treatment group and control group, each of 136 cases. Questionnaire survey evaluated demographic features of the subjects. Gingival index (GI), plaque index (PLI) and conscious symptoms of adjacent teeth of the M3 were detected in both groups at baseline (T0), 1 week (T1), 1 month (T2) and 6 months (T3) after treatment. The impacts of QoL were evaluated using OHIP-14 to measure total scores and various items of OHIP-14 at different observation point. Results: The percentage of swelling and toothache in the treatment group was significantly lower than that in the control group at T1, T2 and T3. Significant differences could be seen in GI and PLI between the treatment and control groups at T2 and T3. The total score of OHIP-14 in T2 and T3 was significantly lower than that in T0 and T1 in the treatment group. The 14 items scores and the percentage of positive reaction in the treatment group were significantly lower than those in the control group at T2 and T3. Conclusion: M3 extraction had significant impacts on the periodontal status of the second molar and quality of life. This study would provide an important basis for the prophylactic removal of M3 in clinical work.

Objective: The study investigated the biological effects and molecular mechanisms of platelet-rich plasma (PRP) on periodontal bone regeneration. Methods: Electronic and manual searches were searched up to 1 October 2022 in the following databases: Pubmed, Scopus, Cochrane Library and Embase. [Platelet rich plasma or platelet or growth factors] and [periodontal] or [bone regeneration or bone defect or bone reconstruction] were used for searching. This study reviewed and analyzed published papers associated with PRP and periodontal bone defect restoration or bone regeneration or bone reconstruction. Results: Different growth factors exhibited varied biological characteristics and function. In-vitro studies, animal experiments and clinical studies confirmed that PRP displayed assorted role in periodontal bone defects repair. The growth factors secreted from PRP can promote new bone formation, soft tissue regeneration and wound healing. The fiber three-dimensional structure in PRP is conducive to the growth and migration of cells and provides strong support for the regeneration of periodontal soft and hard tissues. The anti-inflammatory characteristics of PRP are also closely related to the repair of periodontal bone defects. Conclusion: PRP played an important biological effect on periodontal bone regeneration. The mechanism is closely related to PRP promoting the growth, proliferation, differentiation and migration of periodontal ligament cells and osteoblasts, and the fiber stereo configuration of PRP and the anti-inflammatory effect of leukocytes.