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Introduction: This study was performed to compare the effects of single and multiple irradiations of low-level laser therapy (LLLT) on bone regeneration in a mid-palatal suture following rapid palatal expansion (RPE). Methods: In this animal study, 40 male Wistar rats underwent RPE for 7 days and were divided into 4 groups including A: single LLLT on day 7, B: Multiple LLLT on days 7, 9, 11, 13 and 15, C: control (no LLLT), and D: sacrificed on day 7. Animals in group D were used to determine the amount of suture expansion. LLLT was done by a diode laser set at an 808 nm wavelength with a useful power output of 100 mW and duration of 0.1 ms. LLLT was applied to three points. After three weeks of retention, the rats were sacrificed and beheaded and the maxilla was evaluated by occlusal radiography, µ-CT, and histomorphometric analyses. A comparison of the mean measurements between the groups was performed using ANOVA and the Tukey post hoc test. Results: Based on occlusal radiography and µCT, bone density in group B was significantly higher than group A and group C (P<0.05). There was no significant difference in bone density between group A and group C (P>0.05). Mean suture width (MSW) in group B was significantly lesser than the control group (P=0.027) while there was no significant difference between MSWnin groups A and B (P=0.116) and groups A and C (P=0.317). Conclusion: It may be concluded that multiple low-power laser irradiation improves bone regeneration after RPE while single irradiation does not have a positive effect.
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INTRODUCTION: One of the most common orthodontic problems is maxillary constriction, which is mostly treated by rapid palatal expansion (RPE). However, its high rate of relapse and prolonged retention period have led to some challenges for orthodontists. To encounter these issues, accelerating bone regeneration can provide long-term stability of expanded maxilla. The present study aimed to evaluate the effect of low-level laser therapy (LLLT), bone marrow-derived mesenchymal stem cells (BMSCs) and their combination on promoting bone regeneration of the inter-maxillary suture after RPE in rats. MATERIALS AND METHOD: Total of 60 rats went under RPE treatment. After 7 days, retention period started and interventions (group A, Control (saline); group B, LLLT; group C, BMSCs; group D, LLLT + BMSCs) were performed in the sutural area. After 21 days, radiographic and histological analyses were done. Histological analyses were conducted to evaluate the following criteria of the newly formed bone: the number of osteoblasts, new bone formation, vascularization, connective tissue. Moreover, sutural width was assessed in histologic images. To evaluate bone density at suture area, gray scale and Hounsfield Unit values were measured based on the occlusal radiographic and Micro-Computed topography images respectively. RESULTS: Only in group C and D, osteoblasts and new bone formation were observed in all of the samples. There were no significant differences among the study groups regarding the post-treatment sutural width (P > 0.05). In the radiographic analysis, only group D showed more bone density compared to the control group (P = 0.022). Similarly, in micro-CT analysis, the most bone density was observed in group D which was significantly more than the control group (P = 0.013). CONCLUSION: Our findings suggest that the application of LLLT and BMSCs is the most beneficial approach in accelerating bone regeneration in the inter-maxillary suture.
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Introduction: Temporomandibular joint disorders (TMDs) are the most common source of pain on the face. There are multiple etiologies, and several types of treatment have been reported. The use of non-invasive and reversible therapies in the treatment of such problems is recommended. The present study evaluated the effect of low-level laser (LLL) therapy and transcutaneous electric nerve stimulation (TENS) on TMDs. Methods: In this single-blind study, 40 patients with temporomandibular disorders were randomly divided into four groups: TENS (TENSTem dental), LLL (diode 810 nm CW), shamTENS, and sham-LLL. All subjects were examined and data on pain and tenderness in the temporomandibular joint (TMJ) and masticatory muscles (using the visual analogue scale) and mouth-opening (distance between incisal edges before feeling pain; mm) were collected before baseline (T1), after each session (T2-T5) and one month after the end of the sessions (T6)), and analyzed using repeated measure analysis of variance (ANOVA) and Bonferroni statistical tests. A P value < 0.05 was considered significant. Results: The decrease in pain (P=0.000), tenderness (P=0.000) and increase in mouth-opening ability (P=0.002) was greater in the TENS and LLL groups than in the placebo groups. At the one-month follow-up, significant decrease in pain and tenderness was recorded in the TENS and LLL groups (P=0.000). There was no significant differences between TENS and LLL and the placebo groups for maximum mouth-opening at the end of the study (P=0.692). Conclusion: Using TENS or LLL therapy can improve TMD symptoms at least for the short term. Although the effects of the placebo played a role in improving symptoms, their effects were less important.