Do low-level laser therapy and platelet-rich plasma affect bone calcium content and mechanical properties at tooth extraction sites? An experimental study in the rat

Abstract Background: Both low-level laser therapy (LLLT) and platelet-rich plasma (PRP) have been suggested to improve the repair of mandibular defects. This study investigated the mechanical properties and calcium content at the tooth extraction site in the rat model exposed to LLLT (λ=808 nm) with or without PRP. Methods : In this experimental rat model, the maxillary left first molar teeth were extracted in twenty male rats. Then, they were divided randomly into four groups. Group one: the extraction sockets were treated by 0.9 W gallium-aluminum-arsenide (GaAlAs) diode laser irradiation for five minutes every 72 hours after extraction for the next 12 days (4 times in overall); group two: PRP was placed in the extraction sockets; group three: a combination of both treatments (LLLT+PRP) was done; group four: untreated extraction socket as the control group. All rats were sacrificed 30 days post-operative. All bone blocks of the extracted socket were prepared for mechanical strength and calcium content analyses. Results: The compressive strength in the laser group was significantly higher than in both the control and PRP-treated groups (p=0.0001 and 0.00044, respectively). Although a combination of both PRP and LLLT elevated the mechanical strength compared to the control and PRP groups, it was statistically similar to LLLT/PRP group. Calcium content did not change by any of the treatments. Conclusions: Mechanical and chemical analyses on the bone blocks demonstrated that LLLT improved bone healing; however, PRP alone or combined with LLLT did not show a synergistic impact.