Objective: The study aimed to systematically appraise the evidence on the effects of low level laser therapy (LLLT) on bone healing following rapid maxillary expansion (RME). Methods: Electronic search was performed in MEDLINE, Scopus, and Embase databases using appropriate Medical Subject Heading terms, with no time restriction. ClinicalTrials.gov ( www.clinicaltrials.gov ) was also searched using the terms “low level laser therapy” and “maxillary expansion.” Selection criteria: Original research articles on human clinical trials that involved both RME and LLLT were included. Animal studies were also assessed on an exploratory basis. Results: The search strategy resulted in 12 publications (4 randomized controlled trials, 8 animal studies). In human studies, bone density was assessed radiographically (either two-dimensional or three-dimensional imaging). Regardless of the discrepancies in the intervention protocols, the total of the trials revealed that LLLT had stimulatory effects on bone regeneration after RME. The studies in animal models measured the formation and maturation of new bone qualitatively or quantitatively. Conclusions: Despite the limited evidence, LLLT seems to be a promising intervention for stimulating immediate bone regeneration and healing after midpalatal suture expansion. Long-term, randomized clinical trials are needed to formulate safe results and establish a reliable clinical protocol, rendering the method clinically applicable.

Objective: The purpose of this study was to investigate the influence of bioglass, Nd:YAG laser irradiation and their combination on dentinal tubuli occlusion as a potential dentinal hypersensitivity treatment for cervical dentinal hypersensitivity (CDH). Background data: CDH affects 8–30% of adults and nearly 85% of perio-treated patients. Various treatment schemes have been applied for treating CDH, among them being fluoride application, laser irradiation, and, recently, bioglass (NovaMin ^® ). In this in vitro study, we evaluated the efficacy of NovaMin ^® paste (NM) (Denshield, Sultan, USA), Nd:YAG laser irradiation (L) at various power settings, and their combination, on dentinal orifice occlusion (DOO) as potential treatments for CDH. Methods: Forty-nine human dentin surfaces were organized into seven equal groups: groups A and B received NM followed by L (0.5 and 1 W, respectively); groups C and D received L (0.5 and 1 W, respectively) followed by NM; group E received NM; and groups F and G received L (0.5 and 1 W, respectively). Specimens were evaluated with regard to DOO under environmental scanning electron microscope. Results: Treatment modality significantly affected DOO ( p =0.012). Groups B and G scored higher DOO than the rest. By ordinal logistic regression (with boostrap standard errors), the combination of NM followed by 1 W Nd:YAG laser irradiation (group B) significantly ( p <0.001) contributed to DOO, compared with groups A, C, D, E, and F. Conclusions: Under the limitations of this study, Nd:YAG laser irradiation at 1 W, alone or combined with NM, is a superior method for producing DOO, and may lead to an effective treatment modality for CDH.