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Autologous platelet concentrate for post-extraction socket healing: a systematic review.

BACKGROUND
Autologous platelet concentrates are claimed to enhance hard and soft tissue healing due to the considerable amount of growth factors that are released after application in the surgical site. However, their actual efficacy for improving tissue healing and regeneration in oral surgery applications is controversial. Tooth extraction socket healing represents a proper model to study the effect of autologous platelet-enriched preparations due to the concomitant occurrence of different processes of both hard and soft tissue healing.


PURPOSE
To evaluate the efficacy of platelet concentrates for alveolar socket healing after tooth extraction, by conducting a systematic review.


MATERIALS AND METHODS
Medline, Embase and Cochrane Central Register of Controlled Trials were searched using a combination of specific search terms. The last electronic search was performed on 15 June, 2014. Manual searching of the relevant journals and of the reference lists of reviews and all identified randomised controlled trials was also performed. Randomised controlled trials evaluating the effect of a platelet concentrate on fresh extraction sockets were included. Further inclusion criteria were that at least 10 patients were treated (at least 5 per group) and there was a minimum follow-up duration of 3 months. Primary outcomes were postoperative complications, patient satisfaction and postoperative discomfort. Secondary outcomes were any clinical, radiographic, histological and histomorphometric variables used to assess hard and soft tissue healing. Assessment of the methodological quality of the trials was made. RESULTS were expressed as fixed-effects models using mean differences for continuous outcomes and risk ratios for dichotomous outcomes, with 95% confidence intervals (CI).


RESULTS
The initial search yielded 476 articles. After the screening process, six articles met the inclusion criteria (199 teeth in 156 patients). Three studies were considered at high risk of bias, two at medium risk and one at low risk. A large heterogeneity in study characteristics and outcome variables used to assess hard tissue healing was observed. A meta-analyses of two studies reporting histomorphometric evaluation of bone biopsies at 3 months' follow-up showed greater bone formation when platelet concentrates were used, as compared to control cases (P <0.001; mean difference 20.41%, 95% C.I. 13.29%, 27.52%). Beneficial effects of platelet concentrates were generally but not systematically reported in most studies, in particular when considering the effects on soft tissue healing and the patient's reported postoperative symptoms like pain and swelling, although no meta-analysis could be done for such parameters.


CONCLUSIONS
Although the results of the meta-analysis of the present review are suggestive for a positive effect of platelet concentrates on bone formation in post-extraction sockets, due to the limited amount and quality of the available evidence, they need to be cautiously interpreted. A standardisation of the experimental design is necessary for a better understanding of the true effects of the use of platelet concentrates for enhancing post-extraction socket healing.