Effects of Photobiomodulation and Ultrasound Applications on Orthodontically Induced Inflammatory Root Resorption; Transcriptional Alterations in OPG, RANKL, Cox-2: An Experimental Study in Rats.

Objective: The aim of this study was to evaluate and compare the reparative and inhibitory effects of a light-emitting diode-mediated photobiomodulation (PBM) and of a low-intensity pulsed ultrasound (LIPUS) on orthodontically induced inflammatory root resorption (OIIRR). Materials and methods: Forty-nine Wistar rats were divided into four groups: untreated group (negative control), group treated with orthodontic appliances (positive control), PBM-treated group (wavelength: 618 nm, output power density: 20 mW/cm2), and LIPUS-treated group (frequency: 1.5% ± 5% MHz, pulse repetition ratio: 1.0% ± 10% kHz, effect area: 3.88% ± 1% cm2 and intensity: 30% ± 30% mW/cm2). OIIRR was induced experimentally in rats for 14 days with an applied force of 100g, and therapeutic approaches were performed concurrently. At the end of the experiment, upper first molar teeth of rats were prepared for genetic analysis, scanning electron microscopy, hematoxylin and eosin staining, and tartrate-resistant acid phosphatase staining. Kruskal-Wallis and post hoc Dunn's tests were performed. Results: Number of osteoclasts (p < 0.01), number of resorption lacunae and resorption area ratio (p < 0.001) decreased and number of total cells (p < 0.001) increased with the PBM and LIPUS applications when compared with the positive control group. Receptor activator of nuclear factor kappa B ligand (RANKL) levels of PBM and LIPUS groups were lower (p < 0.001), and osteoprotegerin (OPG) levels were higher (p < 0.001) than the positive control group. Cyclooxygenase-2 (Cox-2) expression significantly decreased with LIPUS and PBM administrations (p < 0.05). No significant difference was observed among PBM and LIPUS groups. Conclusions: PBM and LIPUS applications showed marked inhibitory and reparative effects on OIIRR by modulating the OPG/RANKL ratio, Cox-2 expression, and cell differentiation of osteoblasts and osteoclasts.

Light emitting diode mediated photobiomodulation therapy improves orthodontic tooth movement and miniscrew stability: A randomized controlled clinical trial.

BACKGROUND AND OBJECTIVES: The aim of this study was to evaluate the effects of light-emitting diode-mediated-photobiomodulation therapy (LPT) on the stability of miniscrews, rate of orthodontic tooth movement, and interleukin-1ß levels in gingival and peri-implant crevicular fluid. MATERIALS AND METHODS: This study was a double blind, randomized placebo/control matched pairs clinical trial to test the efficacy of LPT. This split-mouth design study consisted of 20 patients (13 girls, 7 boys). The eligibility criteria included patients who had extraction of maxillary first premolars. Mini-screws were placed between maxillary first molars and second premolars on both sides as anchorage units. LPT was applied with an energy density of 20 mW/cm2 over a period of 21 successive days (20 minutes per day) over the movement of canine teeth on the test side and using a pseudo application on the placebo side. The main outcome of this study was to assess effect of LPT on the rate of orthodontic tooth movement. The secondary outcomes were measuring stability of miniscrews and interleukin-1ß levels in gingival and peri-implant crevicular fluid after LPT. Randomization was accomplished with random LPT application side selection by coin toss. Measurements were made by blinding clinicians. Blinding of the patients was achieved using the same LPT device on both sides but irradiating only one side. For statistical comparison, paired samples t-test and one-way analysis of variance (ANOVA) were used at P < 0.05 level. RESULTS: Miniscrew stability was similar between control and LPT groups at baseline (T0) and the 1st month (T1). However, miniscrew stability was significantly increased in the LPT group in 2nd (T2) and 3rd (T3) months. Comparison of tooth movement during three different time intervals (T1-T0, T2-T1, and T3-T2) revealed that statistically significantly increased in every time intervals after LPT. No statistically significant change was detected in the IL-1ß levels between groups. CONCLUSION: LPT had the potential of accelerating orthodontic tooth movement and had a positive effect on miniscrew stability. Lasers Surg. Med. 48:936-943, 2016. © 2016 Wiley Periodicals, Inc.

Effect of LED-mediated-photobiomodulation therapy on orthodontic tooth movement and root resorption in rats.

The aim of this experimental study was to evaluate the effects of light-emitting diode-mediated-photobiomodulation therapy (LPT), on the rate of orthodontic tooth movement (TM) and orthodontically induced root resorption, in rats. Twenty male 12-week-old Wistar rats were separated into two groups (control and LPT) and 50 cN of force was applied between maxillary left molar and incisor with a coil spring. In the treatment group, LPT was applied with an energy density of 20 mW/cm(2) over a period of 10 consecutive days directly over the movement of the first molar teeth area. The distance between the teeth was measured with a digital caliper on days 0 (T0), 10 (T1), and 21 (T2) on dental cast models. The surface area of root resorption lacunae was measured histomorphometrically using digital photomicrographs. Mann-Whitney U and Wilcoxon tests were used for statistical evaluation at p < 0.05 level. TM during two different time intervals (T1-T0 and T2-T1) were compared for both groups and a statistically significant difference was found in the LPT group (p = 0.016). The TM amount at the first time period (1.31 ± 0.36 mm) was significantly higher than the second time period (0.24 ± 0.23 mm) in the LPT group. Statistical analysis showed significant differences between two groups after treatment/observation period (p = 0.017). The magnitude of movement in the treatment group was higher (1.55 ± 0.33 mm) compared to the control group (1.06 ± 0.35 mm). Histomorphometric analysis of root resorption, expressed as a percentage, showed that the average relative root resorption affecting the maxillary molars on the TM side was 0.098 ± 0.066 in the LPT group and 0.494 ± 0.224 in the control group. Statistically significant inhibition of root resorption with LPT was determined (p < 0.001) on the TM side. The LPT method has the potential of accelerating orthodontic tooth movement and inhibitory effects on orthodontically induced resorptive activity.

Light-emitting diode photobiomodulation: effect on bone formation in orthopedically expanded suture in rats--early bone changes.

The aim of this experimental study was to evaluate histomorphometrically the effects of light-emitting diode (LED) photobiomodulation therapy (LPT) on bone formation in response to expansion of the interpremaxillary suture in rats. Twenty male, 50- to 60-day-old Wistar rats were divided into two equal groups (control and experimental). Both groups were subjected to expansion for 5 days, and 50 cN of force was applied to the maxillary incisors with helical spring. An OsseoPulse® LED device, 618-nm wavelength and 20-mW/cm(2) output power irradiation, was applied to the interpremaxillary suture for 10 days. Bone formation in the sutural area was histomorphometrically evaluated, including the amount of new bone formation (in square micrometers), number of osteoblasts, number of osteoclasts, and number of vessels. Mann-Whitney U test was used for statistical evaluation at p < 0.025 level. Significant differences were found between groups for all investigated histomorphometric parameters. New bone formation area (p = 0.024, 1.48-fold), number of osteoblasts (p < 0.001, 1.59-fold), number of osteoclasts (p = 0.004, 1.43-fold), and number of vessels (p = 0.007, 1.67-fold) showed higher values in the experimental group than the control. Bone histomorphometric measurements revealed that bone architecture in the LPT group was improved. The application of LPT can stimulate bone formation in the orthopedically expanded interpremaxillary suture during expansion and the early phase of the retention periods.

Resonance frequency analysis of orthodontic miniscrews subjected to light-emitting diode photobiomodulation therapy.

The aim of this prospective experimental study was to evaluate the effect of light-emitting diode (LED) photobiomodulation therapy (LPT) on the stability of immediately loaded miniscrews under different force levels, as assessed by resonance frequency analysis (RFA). Sixty titanium orthodontic miniscrews with a length of 8 mm and a diameter of 1.4 mm were implanted into cortical bone by closed flap technique in each proximal tibia of 15 New Zealand white adult male rabbits (n = 30). The animals were randomly divided into irradiated and control groups under different force levels (0, 150, and 300 cN). OsseoPulse® LED device (Biolux Research Ltd.) 618 nm wavelength and 20 mW/cm(2) output power irradiation (20 minutes/day) was applied to the miniscrews for 10 days. The RFA records were performed at miniscrew insertion session (T1) and 21 days after surgery (T2). Wilcoxon and Mann-Whitney U-tests were used for statistical evaluation at P < 0.005 level. It was found that initial primer stability of all miniscrews was similar in all groups at the start of the experimental procedure. Statistically significant differences were found for changes in implant stability quotient (ISQ) values between LED-photobiomodulated group and the control (0 cN, P = 0.001; 150 cN, P < 0.001; and 300 cN, P < 0.001). Significant increase was found in ISQ values of LPT applied miniscrews under 0 cN (+11.63 ISQ), 150 cN (+10.50 ISQ), and 300 cN (+7.00 ISQ) force during observation period. By the increase of force levels, it was determined that ISQ values decreased in non-irradiated control miniscrews. Within the limits of this in vivo study, the present RFA findings suggest that LPT might have a favourable effect on healing and attachment of titanium orthodontic miniscrews.

The association of occlusal factors with masticatory muscle tenderness in 10- to 19-year old Turkish subjects.

The aims of this study were (1) to investigate the relationship between occlusal factors and masticatory muscle tenderness among 10- to 19-year-old (mean 14 years eight months) Turkish subjects and (2) to identify possible sex differences between them. The sample consisted of 716 individuals (355 male and 361 female subjects). Tenderness with palpation of masseter and temporalis muscles and functional manipulation of lateral and medial pterygoid muscles was registered. The examiners recorded the Angle classification bilaterally for molars, presence of anterior and posterior crossbites, excessive overjet, open and deep bites, functional shift, and severity of anterior crowding. Associations between the occlusal factors and muscle tenderness according to sex were evaluated with chi-square analysis. Statistically significant associations were found between masticatory muscle tenderness and all the investigated occlusal factors except posterior crossbite and functional shift. Masseter, medial, and lateral pterygoid muscle tenderness was higher in female subjects. Medial and lateral pterygoid muscle tenderness in Class I cases and masseter and medial pterygoid muscle tenderness in Class II, division 1 malocclusion cases were higher in female subjects (P < .05). In open-bite cases, medial pterygoid muscle tenderness (P < .05), in deep-bite cases, masseter (P < .01) and medial pterygoid (P < .05) muscle tenderness, and in excessive overjet cases, masseter muscle tenderness (P < .05) were also higher in female subjects. These results suggest that greater masticatory muscle tenderness in female subjects may contribute to the greater prevalence of temporomandibular disorders in them.

The effects of early preorthodontic trainer treatment on Class II, division 1 patients.

The aim of this study was to clarify the dentoskeletal treatment effects induced by a preorthodontic trainer appliance treatment on Class II, division 1 cases. Twenty patients (10 girls and 10 boys, mean age 9.6 +/- 1.3 years) with a Class II, division 1 malocclusion were treated with preorthodontic trainer appliances (Myofunctional Research Co., Queensland, Australia). The patients were instructed to use the trainer every day for one hour and overnight while they slept. A control group of 20 patients (mean age 10.2 +/- 0.8 years) with untreated Class II, division 1 malocclusions was used to eliminate possible growth effects. Lateral cephalograms were taken at the start and end of treatment. Final cephalograms were taken 13.1 +/- 1.8 months after trainer application, compared with a mean of 11.2 +/- 2.4 months later for the control group. The mean and standard deviations for cephalometric measurements were analyzed by paired-samples t-test and independent-samples t-tests. At the end of the study period, the trainer group subjects showed significant changes including anterior rotation and sagittal growth of the mandible, increased SNB and facial height, reduced ANB, increased lower incisor proclination, retroclination of upper incisors, and overjet reduction. However, only total facial height increase, lower incisor proclination, and overjet reduction were significantly higher when compared with the changes observed in the control group. This study demonstrates that the preorthodontic trainer application induces basically dentoalveolar changes that result in significant reduction of overjet and can be used with appropriate patient selection.

The relationship between bruxism and occlusal factors among seven- to 19-year-old Turkish children.

The aim of this study was (1) to investigate the relationship between occlusal factors and bruxism among 965 Turkish subjects (472 boys and 493 girls) with a mean age of 12.8 years (range, seven to 19 years); and (2) to identify possible sex differences between girls and boys. This sample was divided into two groups of bruxers or nonbruxers based on a clinical examination and self-reports. The examiner recorded the Angle molar classification bilaterally, severity of anterior crowding, existence of anterior and posterior crossbite, open and deep bite, functional shift, and excessive overjet. The relationships between occlusal factors and bruxism and sex differences between boys and girls were evaluated with chi-square analysis (chi2) using the SPSS software package. The results showed that bruxism was diagnosed in 12.6% of all subjects. The evaluation of the findings indicated that no statistically significant relationships were determined between bruxism and occlusal factors. No sex differences were found between occlusal factors in relation to bruxism. The prevalence of bruxism in boys and girls was similar, and no statistically significant differences were found. It is concluded that none of the occlusal factors seem to play a role in the development of bruxism. However, additional longitudinal studies with larger samples need to be conducted to determine if there is any relationship between occlusal factors and bruxism.