Aim: Platelet‐rich plasma (PRP) is an autologous blood‐derived material that has been used to enhance bone regeneration. Clinical studies, however, reported inconsistent outcomes. This study aimed to assess the effect of changes in leucocyte and PRP (L‐PRP) composition on bone defect healing.Materials and Methods: L‐PRPs were prepared using different centrifugation methods and their regenerative potential was assessed in an in‐vivo rat model. Bilateral critical‐size tibial bone defects were created and filled with single‐spin L‐PRP, double‐spin L‐PRP, or filtered L‐PRP. Empty defects and defects treated with collagen scaffolds served as controls. Rats were euthanized after 2 weeks, and their tibias were collected and analysed using micro‐CT and histology.Results: Double‐spin L‐PRP contained higher concentrations of platelets than single‐spin L‐PRP and filtered L‐PRP. Filtration of single‐spin L‐PRP resulted in lower concentrations of minerals and metabolites. In vivo, double‐spin L‐PRP improved bone healing by significantly reducing the size of bone defects (1.08 ± 0.2 mm³) compared to single‐spin L‐PRP (1.42 ± 0.27 mm³) or filtered L‐PRP (1.38 ± 0.28 mm³). There were fewer mast cells, lymphocytes, and macrophages in defects treated with double‐spin L‐PRP than in those treated with single‐spin or filtered L‐PRP.Conclusion: The preparation method of L‐PRP affects their composition and potential to regenerate bone.

Objectives: This systematic review compared platelet concentrates (PCs) versus hyaluronic acid (HA) or saline/Ringer’s solution injections as treatments of temporomandibular osteoarthritis and disc displacement in terms of pain and maximum mouth opening (MMO). Methods: PubMed, Cochrane, and Scopus were searched up to March 6, 2020. Inclusion criteria were randomized clinical trials (RCTs). Exclusion criteria were case series, observational studies, animal studies, and reviews. The Effective Public Health Practice Project (EPHPP) quality assessment tool was used to assess the risk of bias in the included studies. The weighted mean difference was used to compare the results. Results: Nine RCTs were included with a total of 407 patients. The numbers of joints treated were 262, 112, and 112 in the PC, HA, and saline groups, respectively. The quality of studies was rated as strong in 4 studies, moderate in 4 studies, and weak in 1 study. The meta-analysis revealed that PCs decreased pain visual analogue scale (VAS) scores compared to HA by an average of −1.11 (CI, −1.62 to −0.60; P < 0.0001) and −0.57 (CI, −1.55 to 0.41; P = 0.26) at 3 and 12 mo follow-up respectively. Also, the average decrease in pain scores with PC compared to saline was −1.33 (CI, −2.61 to −0.06; P = 0.04), −2.07 (CI, −3.46 to −0.69; P = 0.003), and −2.71 (CI, −4.69 to −0.72; P = 0.008) at 3, 6, and 12 mo, respectively. Regarding MMO measurements, PC was comparable to HA, but it was significantly better than saline after 3 and 6 mo [2.9 mm (CI,1.47 to 4.3; P < 0.0001), and 1.69 mm (CI, 0.13 to 3.25; P = 0.03) respectively]. Conclusion: PC reduces pain VAS scores compared to HA during the first 3 m after treatment, and when compared to saline, it reduces pain and increases MMO for longer durations. However, due to differences between groups regarding PC preparation protocols and study heterogeneity, further standardized RCTs are required. Knowledge Transfer Statement: This study provides researchers and clinicians with quantitative and qualitative analyses of the current evidence regarding the clinical outcomes of platelet concentrate injections in the treatment of temporomandibular joint osteoarthritis and disc displacement in terms of pain control and maximum mouth opening.

Donepezil is an acetylcholinesterase inhibitor commonly used to treat mild to moderate Alzheimer’s disease. Its use has been associated with increased bone mass in humans and animals. However, the effect of postoperative administration of donepezil on bone healing remains unknown. Therefore, this study aimed to assess the impact of postoperative injection of donepezil on bone healing, titanium-implant osseointegration, and soft tissue healing. Twenty-two Sprague-Dawley rats were randomly assigned to receive a daily dose of either donepezil (0.6 mg/kg) or saline as a control. In each rat, a uni-cortical defect was created in the right tibia metaphysis and a custom-made titanium implant was placed in the left tibiae. After two weeks, rats were euthanized, and their bones were analysed by Micro-CT and histology. The healing of bone defect and implant osseointegration in the rats treated with donepezil were significantly reduced compared to the saline-treated rats. Histomorphometric analysis showed lower immune cell infiltration in bone defects treated with donepezil compared to the saline-treated defects. On the other hand, the healing time of soft tissue wounds was significantly shorter in donepezil-treated rats compared to the controls. In conclusion, short-term administration of donepezil hinders bone healing whereas enhancing soft tissue healing.

Background: The socket shield technique (SST) could address the challenges in immediate implant placement by minimizing post-extraction bone resorption while maintaining soft tissue levels. This study aimed to summarize the available evidence and systematically assess the effectiveness of SST immediate implant placement regarding all outcomes (bone loss, esthetics, implant stability, probing depth, complications, and survival rate). Methods: We searched seven electronic databases through April 2023 to identify randomized clinical trials that assessed the effect of immediate implant placed with SST (test group) versus other implant placement protocols without SST. The risk of bias was assessed using Cochrane’s randomized trial quality assessment Tool (RoB 2.0). Random-effects meta-analysis was conducted, with mean difference and 95% confidence intervals (MD, 95% CI) as effect estimates. We used the GRADE approach to assess the certainty of evidence. Results: Twelve RCTs, involving 414 immediate implants, placed in 398 patients, were included. Meta-analyses revealed that the immediate implants placed with SST had a statistically significant decrease in horizontal (MD = −0.28, 95% CI [−0.37, −0.19], p < 0.0001), vertical (MD = −0.85, 95% CI [−1.12, −0.58], p < 0.0001), and crestal (MD = −0.35, 95% CI [−0.56, −0.13], p = 0.002) bone loss, as well as probing depth (MD = −0.64, 95% CI [−0.99, −0.29], p = 0.0003). Additionally, SST had a significant increase in implant stability (MD = 3.46, 95 % CI [1.22, 5.69], p = 0.002) and pink esthetic score (MD = 1.60, 95% CI [0.90, 2.30], p < 0.0001). Only two studies reported shield exposure incidences in the SST group; however, all studies revealed no implant failure and a 100% survival rate. The evidence certainty was assessed as very low. Conclusions: Based on limited evidence, SST was more effective in minimizing bone resorption and improving implant stability and esthetic outcomes than conventional immediate implant placement. Still, SST could not be recommended as a routine clinical protocol due to the lack of a standardized surgical approach; thus, further high-quality RCTs are required to support this conclusion.