Effects of two wattages of low-level laser therapy on orthodontic tooth movement

IntroductionMixed outcomes have been found in animal and clinical studies with regard to the use of low-level laser therapy (LLLT) as a modality to accelerate orthodontic tooth movement (OTM). One major reason for the variable findings is the different methodologies and protocols for laser therapy use.ObjectiveThe aim of this study was to determine whether orthodontically moved molars exposed to two different wattages at the same energy density of LLLT exhibited differences in the amount of tooth movement and molecular and histological changes in the adjacent periodontal areas.MethodsAn orthodontic force was applied to rat upper first molars exposed to 500 mW (EX-500) and 1000 mW (EX-1000) of laser application, with a control group (CT) with no laser application. Gene expression in the periodontal ligament (PDL) and histology of the palatal gingiva of the molars were analyzed.ResultsThere was a statistically significant difference for OTM between EX-500 but not between EX-1000 and CT groups. RANKL and MMP-13 expression levels in the PDL of orthodontically moved molars, however, were increased significantly in laser-exposed groups compared to CT. Early signs of dysplasia were observed in over half of the animals in the EX-1000 group.ConclusionsOur results provide evidence for molecular changes and the potential dysplastic effects of laser on the surrounding soft tissues. Further studies are needed to better identify an optimum laser protocol to maximize the desired effect.     

Low-level laser therapy effectiveness in accelerating orthodontic tooth movement: A randomized controlled clinical trial

Objective:To evaluate the effectiveness of low-level laser therapy (LLLT) in accelerating orthodontic tooth movement of crowded maxillary incisors.Materials and Methods:This two-arm, parallel-group, randomized controlled trial involved 26 patients with severe to extreme maxillary incisors irregularity according to Little''s irregularity index, indicating two first premolars extraction. Patients were randomly assigned to either the laser group or the control group (13 each). Following premolars extraction, orthodontic treatment with fixed appliances was initiated for both groups. Immediately after insertion of the first archwire, patients in the laser group received a LLL dose from an 830-nm wavelength Ga-Al-As semiconductor laser device with energy of 2 J/point. The laser was applied to each maxillary incisor''s root at four points (two buccal, two palatal). Application was repeated on days 3, 7, 14, and then every 15 days starting from the second month until the end of the leveling and alignment stage. Alignment progress was evaluated on the study casts taken before inserting the first archwire (T0), after 1 month of treatment commencement (T1), after 2 months (T2), and at the end of the leveling and alignment stage (T3). The outcome measures were the overall time needed for leveling and alignment and the leveling and alignment improvement percentage.Results:A statistically significant difference was found between the two groups in the overall treatment time (P < .001) and the leveling and alignment improvement percentage at T1 (P = .004) and T2; (P = .001).Conclusion:LLLT is an effective method for accelerating orthodontic tooth movement.     

Laser-Aided Circumferential Supracrestal Fiberotomy and Low-Level Laser Therapy Effects on Relapse of Rotated Teeth in Beagles

Objective:To investigate the effectiveness and periodontal side effects of laser circumferential supracrestal fiberotomy (CSF) and low-level laser therapy (LLLT) on orthodontically rotated teeth in beagles.Materials and Methods:Eighteen mandibular incisors from nine dogs were divided into three groups by treatment (n  =  6/group): A, orthodontic couple force application only (control); B, laser CSF following orthodontic couple force application; and C, LLLT following orthodontic couple force application. Both mandibular lateral incisors were rotated for 4 weeks, and the relapse tendency was observed for 4 weeks more without any retainers. The amount of relapse, sulcus depth, and gingival recession were measured at weeks 4 and 8. One-way analysis of variance (ANOVA) and Scheffé''s post hoc test were used for data analysis. Tissue specimens were examined at week 8 under light microscopy after hematoxylin-eosin (H&E) and Masson''s trichrome staining.Results:The mean percentage of relapse was 41.29% in group A, 14.52% in group B, and 56.80% in group C (P < .001). Four weeks after laser CSF, the sulcus depth increased by 0.67 mm, but no gingival recession was observed. There was no significant difference between groups A and C in terms of sulcus depth and gingival recession.Conclusions:Laser CSF is an effective procedure to decrease relapse after tooth rotation, causing no apparent damage to the supporting periodontal structures, whereas LLLT on orthodontically rotated teeth without retainers appears to increase the relapse tendency.     

低水平激光治疗促进正畸牙齿移动的研究进展

低水平激光治疗（low-level laser therapy ,LLLT）是被FDA批准应用于临床的一种安全、无创的治疗方法,可通过使用600-1000nm的单色可见红光或近红外光对细胞和组织产生光生物刺激作用。目前,LLLT广泛应用于促进伤口愈合,缓解疼痛,减少炎症,再生医学等领域。现有研究认为,LLLT的分子和细胞机制主要与线粒体电子呼吸链有关,通过促进ATP的生成,调节细胞新陈代谢。大量研究表明,LLLT可通过促进牙周膜和牙槽骨的生理性改建,加速牙齿移动,进而缩短正畸治疗时间。由于LLLT的光生物刺激作用、非侵入性方式等特点使其在加速正畸牙齿移动方面有广泛的应用前景。本文就LLLT的作用机制,生物学效应及对正畸治疗中牙齿移动的促进作用进行探讨。     

Effects of different types of tooth movement and force magnitudes on the amount of tooth movement and root resorption in rats

Objective:To investigate differences in the amount of tooth movement and root resorption that occurred after tipping and bodily movement of the maxillary first molar in rats.Materials and Methods:Ten-week-old female Wistar rats were divided into two groups according to type of tooth movement and subdivided into four subgroups according to the magnitude of applied force. Nickel-titanium closed-coil springs exerting forces of 10, 25, 50, or 100 g were applied to the maxillary left first molars to induce mesial tooth movement. We designed a novel orthodontic appliance for bodily tooth movement. Tooth movement distance and root resorption were measured using microcomputed tomography and scanning electron and scanning laser microscopy.Results:The amount of tooth movement in the bodily tooth movement group was less than half that in the tipping tooth movement group. The greatest amount of tooth movement occurred in the 10-g tipping and 50-g bodily tooth movement subgroups, and the amount of tooth movement decreased with the application of an excessive magnitude of force. Conversely, root resorption increased when the heavier orthodontic force was applied in both groups. Root resorption in the tipping tooth movement group was approximately twice that in the bodily tooth movement group.Conclusions:Root resorption in the tipping tooth movement group was more pronounced than that in the bodily tooth movement group. Although the amount of tooth movement decreased when extremely heavy forces were applied, root resorption increased in both the tipping and bodily tooth movement groups in rats.     

Effetti della terapia laser a basso dosaggio nei movimenti dentali ortodontici: analisi della letteratura

Objectives

To investigate the effects of low level laser therapy (LLLT) combined with orthodontic treatment and review significant experimental data documenting the efficacy of laser therapy in this field of dentistry.

Material and methods

The literature was carefully reviewed to identify articles on the use of LLLT during orthodontic tooth movement.

Results

Most of the studies conducted thus far support the use of LLLT in orthodontics.

Conclusions

The number of studies published is currently insufficient to allow one to draw any significant conclusions. Moreover, rigorous, standardized protocols are needed to conduct effective clinical investigations.     

Interventions for accelerating orthodontic tooth movement: A systematic review

Objective:To evaluate the effectiveness of interventions on accelerating orthodontic tooth movement.Materials and Methods:We searched the databases of PubMed, Embase, Science Citation Index, CENTRAL, and SIGLE from January 1990 to August 2011 for randomized or quasi-randomized controlled trials that assessed the effectiveness of interventions on accelerating orthodontic tooth movement. The processes of study search, selection, and quality assessment were conducted independently in duplicate by two review authors. Original outcome data, if possible, underwent statistical pooling by using Review Manager 5.Results:Through a predefined search strategy, we finally included nine eligible studies. Among them, five interventions were studied (ie, low-level laser therapy, corticotomy, electrical current, pulsed electromagnetic fields, and dentoalveolar or periodontal distraction). Six outcomes were evaluated in these studies (ie, accumulative moved distance or movement rate, time required to move tooth to its destination, anchorage loss, periodontal health, pulp vitality, and root resorption).Conclusion:Among the five interventions, corticotomy is effective and safe to accelerate orthodontic tooth movement, low-level laser therapy was unable to accelerate orthodontic tooth movement, current evidence does not reveal whether electrical current and pulsed electromagnetic fields are effective in accelerating orthodontic tooth movement, and dentoalveolar or periodontal distraction is promising in accelerating orthodontic tooth movement but lacks convincing evidence.     

Comparative evaluation of Low Level Laser Therapy and cryotherapy in pain control and wound healing following orthodontic tooth extraction: A double blind study

PurposeTo compare and evaluate pain and healing following orthodontic tooth extraction using Low Level Laser Therapy [LLLT] and Cryotherapy.Materials and methods62 patients referred for orthodontic extraction of bilateral bicuspids were included. Subjects were alternatively divided into two groups with 31 patients each. One of the bilateral extraction sites was subjected to either intervention, LLLT or Cryotherapy, while the other site was kept as control. Pain was assessed for 7 consecutive days by Visual Analogue Scale and Wound healing on 4^th, 7^th and 14^th days using a modified wound healing scale.ResultsPain scores were generally better for Group I [LLLT] when compared to Group II [Cryotherapy] on all days. The highest mean score for pain observed on the 1^st post-extraction day was 4.00 ± 0.93 and 4.16 ± 0.93 for Group I and Group II respectively [p = 0.42]. It was also observed that LLLT helped in better wound healing as compared to cryotherapy with a significant difference in wound healing on 7^th [mean score for Group I and Group II- 1.16 ± 0.52 and 1.6 ± 0.62 respectively: p = 0.01] and 14^th [mean score Group I and Group II- 0.23 ± 0.43 and 1.0 ± 0.58 respectively: p = 0.00] post-extraction days.ConclusionLLLT has better analgesic and wound healing properties as compared to Cryotherapy, suggesting that LLLT should be preferred over cryotherapy whenever possible.     

Effects of low-level laser therapy on the rate of orthodontic tooth movement

OBJECTIVES: To test the hypothesis that mechanical forces combined with low-level laser therapy stimulate the rate of orthodontic tooth movement. STUDY DESIGN: This study was a double blind, randomized placebo/control matched pairs clinical trial to test the efficacy of GaAlAs low-level laser therapy (LLLT) on 12 young adult patients who required retraction of maxillary canines into first premolar extraction spaces using tension coil springs with fixed edgewise appliance. LLLT was applied on the mucosa buccally, distally and palatally to the canine on the test side and using a pseudo-application on the placebo side. Dental impressions and casts were made at the commencement of the trial and at the end of the first, second and third months after starting the trial. Measurement of tooth movements was made on each stage model using a stereo microscope. RESULTS: There was no significant difference of means of the canine distal movement between the LLLT side and the placebo side for any time periods (p-value = 0.77). CONCLUSION: The energy density of LLLT (GaAlAs) at the surface level in this study (25 J/cm(2)) was probably too low to express either stimulatory effect or inhibitory effect on the rate of orthodontic tooth movement.     

低水平激光用于加速正畸牙齿移动的研究进展

以往研究表明,低水平激光治疗(low-level laser therapy, LLLT)可能具有加速牙齿移动的效果。笔者通过查阅文献,总结归纳了LLLT在加速牙齿移动方面的临床效果及其生物学机制。大多数研究认为,LLLT可加速牙齿移动。但也有一些研究认为LLLT不具有加速正畸牙齿移动的效果。LLLT具有小剂量刺激,大剂量抑制的特点。因此,结果差异可能与激光应用时的参数设置有关。LLLT通过光生物调节作用,促进牙齿周围骨组织的改建。研究表明,接受LLLT的患者,牙周组织中的骨细胞数、局部胶原蛋白量、炎症因子的表达情况等均出现差异,但具体的机制尚不明确,有待更深入的研究。     

Vitamin C and eggshell membrane facilitate orthodontic tooth movement and induce histological changes in the periodontal tissue

ObjectivesCollagen remodeling of the periodontal tissue is an important mechanism that involves several biologically active substances to accelerate orthodontic tooth movement. It is known that Vitamin C (VC) enhances collagen production and induces tooth movement. Moreover, the eggshell membrane (ESM) is an integral component of various formulations used to promote wound healing. The purpose of our study was to determine the effects of combined treatment with VC and ESM on periodontal tissues during tooth movement.MethodsNine-week-old male osteogenic disorder Shionogi rats were randomized into four groups: control, VC, ESM, and VC + ESM. The control group was given tap water, and the VC, ESM, and VC + ESM groups were orally administered 0.1% VC solution, 1 wt% ESM solution, and a combination of 0.1 wt% VC and 1 wt% ESM solutions, respectively. A force of 25 or 75 g was applied for 10 days to produce orthodontic tooth movement. Distances of tooth movement were measured on days 3, 7, and 10 of treatment. Histological examination of the periodontal ligament was performed to determine the increase in type I and III collagen levels in response to treatment.ResultsDistances of tooth movement were significantly greater in the VC + ESM group than in the control group. The compression area of the alveolar bone showed increased osteoclastic activity and higher levels of bone resorption in the VC + ESM group. Expression levels of type I and III collagen in the tension area of the alveolar bone were higher in the VC + ESM group than in the control group.ConclusionsThis study revealed that the combined administration of VC and ESM accelerated tooth movement by protecting the periodontal tissue during orthodontic treatment. The combined clinical application of VC and ESM could potentially shorten orthodontic treatment time.     

Combined effect of photobiomodulation with a matrix metalloproteinase inhibitor on the rate of relapse in rats

Objective:To investigate combined effect of photobiomodulation with a matrix metalloproteinase (MMP) inhibitor on the relapse rate in relation to MMP expression in rats.Materials and Methods:Fifty-two rats were divided into four groups according to the treatment modality: control group, irradiation group, doxycycline group, and irradiation with doxycycline group. During a relapse period of 5 days after orthodontic movement, maxillary central incisors were treated by low-level laser therapy (LLLT) as a photobiomodulation and/or doxycycline as a synthetic MMP inhibitor. Relapse rate was evaluated in association with MMP expression at the gene and protein levels.Results:Relapse rates were increased by LLLT (1.57-fold) and decreased by doxycycline (0.83-fold) compared with the control, showing positive correlation with the levels of expression for all MMPs in the periodontal ligament (PDL). LLLT concomitant with doxycycline administration resulted in no significant differences of relapse rate and MMP expression from the control.Conclusions:The combined effect of photobiomodulation with an MMP inhibitor around the relapsing teeth proved to be antagonistic to PDL remodeling activity during relapse. This study suggests a basis for developing a novel biologic procedure targeting the MMP-dependent PDL remodeling to control the relapse rate.     

Evaluation of the use of low-level laser therapy in pain control in orthodontic patients: A randomized split-mouth clinical trial

Objective:To evaluate the effect of using low-level laser therapy (LLLT) to control pain and discomfort during orthodontic treatment.Materials and Methods:A randomized, split-mouth clinical trial was conducted with 30 volunteers in need of orthodontic treatment, of both genders, aged between 18 and 40 years, who were randomly divided into two groups. One hemiarch was considered the exposed group (EG) and the other, the placebo group (PG). Both groups had elastic separators placed mesially and distally to the first molars of the two hemiarches at different times. The EG received an AIGaAs diode LLLT (810 nm, 100 mW, 2J/cm²) application for 15 seconds per point (interdental papilla at the mesial, distal, and near the root apex) immediately after separator placement on the maxillary right side. The PG also had elastics placed around the maxillary right molars, but received only simulated LLLT application. The elastics were left in place for 5 days, and after a waiting period of 1 week, they were inserted on the left side in both groups; however, the order of laser application was changed. While the separator remained in place, the patient marked his degree of perceived discomfort on a Visual Analog Scale (VAS) at 5 minutes (T0), 24 hours (T1), and 120 hours (T2), after LLLT application.Results:A statistically significant difference was observed (P < .005) in reducing discomfort in the exposed group compared with the placebo group. This reduction of discomfort in the EG was observed at all time intervals.Conclusions:A sincle AIGaAs diode LLLT application may be indicated for the control or reduction of pain in the early stages of orthodontic treatment.     

低强度激光促进正畸牙移动的Meta分析和系统评价

目的：评价低强度激光治疗（low?level laser therapy ,LLLT）促进正畸牙移动的有效性及相关风险。方法依据Cochrane Handbook的规范化要求,检索1980年-2014年Medline、PubMed等数据库,运用Review Manager 5.1软件进行Meta分析。结果共纳入6个国家6篇随机对照试验,3篇不完全随机对照试验,211名患者。偏倚风险评价显示5个研究为中度偏倚风险,4个研究为高度偏倚风险。Meta分析结果显示：与对照组相比,LLLT组治疗后7 d,正畸牙移动速度显著增加（MD=0.19,95%CI 0.02?0.37,P=0.03）,该优势持续到治疗后2个月（MD=1.08,95%CI 0.16?2.01,P=0.02）;相对于高能量密度（20或25 J/cm2）的LLLT治疗,低能量密度（2.5,5或8 J/cm2）的LLLT治疗更为有效。结论低能量密度（2.5、5或8 J/cm2）的LLLT能有效促进正畸牙移动,但还需要更多临床随机对照试验支撑。     

Effect of frequent laser irradiation on orthodontic pain: A single-blind randomized clinical trial

Objective:To analyze the effect of low-level laser therapy (LLLT) on perception of pain after separator placement and compare it with perceptions of control and placebo groups using a frequent irradiation protocol.Materials and Methods:Eighty-eight patients were randomly allocated to a laser group, a light-emitting diode (LED) placebo group, or a control group. Elastomeric separators were placed on the first molars. In the laser and LED groups, first molars were irradiated for 30 seconds every 12 hours for 1 week using a portable device. Pain was marked on a visual analog scale at predetermined intervals. Repeated measure analysis of variance was performed for statistical analysis.Results:The pain scores of the laser group were significantly lower than those of the control group up to 1 day. The pain scores in the LED group were not significantly different from those of the laser group during the first 6 hours. After that point, the pain scores of the LED group were not significantly different from those of the control.Conclusions:Frequent LLLT decreased the perception of pain to a nonsignificant level throughout the week after separator placement, compared with pain perception in the placebo and control groups. Therefore, LLLT might be an effective method of reducing orthodontic pain.     

Does the floor of the maxillary sinus affect tooth movement for premolar extraction space closure?

Objective

The study investigated orthodontic tooth movement by comparing various horizontal and angular measures of the teeth having different sinus–root relationship (SRR) of patients undergoing first premolar extraction treatment protocols.

Materials and methods

This retrospective cross-sectional study included 45 Taiwanese adult patients, classified as the control group (n?=?15) and the sinus group (n?=?30) according to SRR. The control group had type I SRR (sinus floor above the level connecting the buccal and palatal root apices), whereas the sinus group included patients with type V SRR (the buccal and palatal root displayed apical protrusion into the sinus floor). Morphology was identified using pretreatment orthopantomograms. Lateral cephalometric measurements were conducted before treatment (T1) and at debonding (T2).

Results

Post debonding, there were no statistically significant difference in the two groups. However, the incisors in the control group became marginally more upright than those of the sinus group, and the molars demonstrated tipping movement with minimal anchorage loss in the sinus group than in the control group. The total treatment time was not significantly different between the 2 groups.

Conclusion

The study revealed that the sinus–root relationship does not affect the orthodontic tooth movement. However, a more extensive 3-D study with larger sample size is strongly recommended before coming to any conclusion.

Clinical relevance

The lining of the floor of the maxillary sinus does not affect the orthodontic tooth movement.

     

Iatrogenic pulpal reactions to orthodontic extrusion

A careful review of the literature reveals an absence of studies about the reactions of dental pulp to orthodontic extrusion. The purpose of the present research investigation is to study the pulpal reactions and the sequence of histologic events in human dental pulp after orthodontic extrusion. The sample consisted of 36 intact maxillary first premolars of young adult orthodontic subjects. The mean age of the subjects was 18 years. Eighteen maxillary first premolars were extruded, under controlled conditions with the aid of fixed edgewise orthodontic appliances, for either 1, 2, or 4 weeks. The contralateral maxillary first premolars were not extruded and were used as controls. Immediately after removal of the appliances, all the maxillary first premolars were extracted. The pulps were histologically examined in a double-blind experiment. The results obtained from this study indicate that certain characteristic pulpal reactions arise from orthodontic extrusion. These reactions involve circulatory disturbances with congested and dilated blood vessels, odontoblastic degeneration, vacuolization and edema of the pulp tissues, and (by the fourth week) manifestation of fibrotic changes. It is speculated that the vacuolization of the pulp tissues (which occurred after the application of extrusive orthodontic forces in young adult subjects) resulted from a prolapse of the pulp, made possible by the relatively wide apical foramina. However, the odontoblastic degeneration is most probably the result of a compromised blood supply. The authors believe that this study constitutes a building block for establishing a more complete biologic foundation for orthodontic tooth movement. Further studies are suggested to reach more definitive conclusions.     

Initial pulp changes during orthodontic movement: histomorphological evaluation

This study evaluated pulp changes in molars of rats submitted to tooth movement by application of a 0.4 N force. Twenty-five adult male Wistar rats (Rattus norvegicus, albinus) were randomly assigned to 5 groups (n=5), being one control group not submitted to force application, and four study groups of 6, 12, 24 and 72 h of force application. The study groups received a 5-mm long nickel-titanium closed coil spring, placed from the right maxillary first molar to the maxillary incisors of each animal. The coil spring was used for mesial inclination of the first molar. After the specific period of tooth movement of each study group, the animals were sacrificed and specimens containing the teeth submitted to movement were processed and stained with hematoxylin and eosin for histological analysis under light microscopy. The results demonstrated alteration of the odontoblastic layer, with hypertrophy of odontoblasts especially at the mesial area of the coronal pulp, edema of the pulp connective tissue in the central area of the pulp, and vascular alteration with accumulation of erythrocytes and leukocytes inside the vessels, especially at the mesial root of the moved teeth. These changes were less remarkable for the 72-h period. Thus, it may be concluded that tooth movement yielded pulpal tissue alterations compatible with an inflammatory process, which are reversible if the aggression is not more intense than the physiological limit of tissue tolerance.     

Leptin Levels in Gingival Crevicular Fluid During Orthodontic Tooth Movement

Objectives: To test if leptin can be detected in the gingival crevicular fluid (GCF) around moving teeth, and to determine whether any changes occur during orthodontic tooth movement.Materials and Methods:An upper canine requiring distal movement served as the test tooth; the contralateral canine was used as a control tooth. The control tooth was included in the orthodontic appliance, but was not subjected to the orthodontic force. GCF sampling from the distal sites of the test and control teeth was done at baseline, 1 hour, 24 hours, and 168 hours.Results:Leptin concentrations of the test teeth decreased in a time-dependent manner. When compared with the baseline measurement, the decrease was significant at 168 hours (P < .05).Conclusions:The concentration of leptin in GCF is decreased by orthodontic tooth movement; the results of the present study also suggest that leptin may have been one of the mediators responsible for orthodontic tooth movement.     

The effects of TBC3214, a selective endothelin ETA receptor antagonist, on orthodontic tooth movement in rats

Many chemical messengers are involved in the process of alveolar bone and periodontal ligament remodelling during orthodontic tooth movement. Among them is probably endothelin-1 (ET-1). Its role in this process has been partly explained using tezosentan, which affects endothelin A (ET(A)) and endothelin B (ET(B)) receptors. Tezosentan enhances orthodontic tooth movement. The aim of this study was to determine the possible effects of a highly selective ET(A) antagonist on orthodontic tooth movement in rats. Thirty male Wistar rats, 11-12 weeks of age, divided into three equal groups. In group I, a closed-coil spring was used and they were treated daily with 15 mg/kg body weight of TBC3214, a highly selective ET(A) antagonist. A closed-coil spring was also used in group II and the animals were treated daily with a placebo. Group III were treated daily with a placebo. The coil spring delivered a force of 25 cN and was attached between the upper left first molar and upper left incisor. The distance between the teeth was measured with a digital calliper (accuracy +/- 0.01 mm) on days 0, 7, 14, 21, 24, 32, 37, and 40. The differences in the distance between the teeth were calculated to determine the amount of tooth movement. Statistical analysis was performed using two-way analysis of variance, Bonferroni's correction, and paired t-tests. The distance between the upper left first molar and the upper left incisor decreased in groups I and II. In group I, tooth movement was significantly less on days 32 and 37 (P < 0.01) and on day 40 (P < 0.001) compared with group II. In group III, the distance between the teeth increased during the study (P < 0.001). In animals treated daily with TBC3214, tooth movement was significantly less compared with the animals treated with a placebo. It is concluded that ET-1, which is the predominant form of endothelin isopeptides, is involved in orthodontic tooth movement in rats, probably by enhancing bone resorption via ET(A) receptors.