We found evidence for beneficial effects of PRP in the treatment of periodontal defects. Evidence for beneficial effects of PRP in sinus elevation appeared to be weak. No conclusions can be drawn about other applications of PRP in dentistry.

Local drug delivery systems have recently been developed for multiple diseases that have the requirements of site‐specific actions, prolonged delivery periods, and decreased drug dosage to reduce undesirable side effects. The challenge for such systems is to achieve directional and precise delivery in inaccessible narrow lesions, such as periodontal pockets or root canals in deeper portions of the dentinal tubules. The primary strategy to tackle this challenge is fabricating a smart tracking delivery system. Here, drug‐loaded biodegradable micromotors showing self‐propelled directional movement along a hydrogen peroxide concentration gradient produced by phorbol esters‐stimulated macrophages are reported. The drug‐loaded poly(lactic‐co‐glycolic acid) micromotors with asymmetric coverage of enzyme (patch‐like enzyme distribution) are prepared by electrospraying and postfunctionalized with catalase via 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide coupling. Doxycycline, a common drug for the treatment of periodontal disease, is selected as a model drug, and the release study by high‐performance liquid chromatography is shown that both the postfunctionalization step and the presence of hydrogen peroxide have no negative influence on drug release profiles. The movement behavior in the presence of hydrogen peroxide is confirmed by nanoparticle tracking analysis. An in vitro model is designed and confirmed the response efficiency and directional control of the micromotors toward phorbol esters‐stimulated macrophages.

A 6.2 mm cranial defect is not a critical-sized defect in rats. Rat PRP had no effect on the early stages of bone healing in addition to an osteoconductive material. Dense HA/beta-TCP particles showed a beneficial effect on bone formation already after 1 and 2 weeks of implantation in non-critical-sized cranial defects in rats.

The effect of platelet-rich plasma (PRP) on bone regeneration, in combination with an osteoconductive material, was evaluated in a rat model. Cranial defects, 6.2 mm in diameter, were filled with HA/beta-TCP particles, HA/beta-TCP particles combined with PRP and HA/beta-TCP particles combined with PRP gel, where some were left empty as a control. After 4 weeks of implantation histological, histomorphometrical and micro-computed tomography analyses revealed no difference in new bone formation among the groups. Further, no additional effect of PRP gel in comparison with PRP liquid was detected, except for the increased handling capacity of the graft. These findings suggest that PRP had no positive effect on bone formation in addition to an osteoconductive material after an implantation period of 4 weeks. Also, no negative effect was seen, and neither PRP nor HA/beta-TCP hampered bone ingrowth into the defects.

No abstract