Optimum force magnitude for orthodontic tooth movement: a systematic literature review

The aim of this study was to perform a meta-analysis of the literature concerning the optimal force or range of forces for orthodontic tooth movement. Over 400 articles both on human research and animal experiments were found in Medline and by hand searching of main orthodontic and dental journals. Articles on animal experiments were in the majority. A wide range of animal species such as rat, cat, rabbit, beagle dog, monkey, mouse, and guinea pig were used. Besides variation in species, there was also a wide range of force magnitudes, teeth under study, directions of tooth movement, duration of experimental period, and force reactivation. Furthermore, hardly any experiments were reported that provide information on the relation between the velocity of tooth movement and the magnitude of the applied force. Data from human research on the efficiency of orthodontic tooth movement appeared to be very limited. The large variation in data from current literature made it impossible to perform a meta-analysis. Therefore, we have systematically reviewed the literature. It appeared that no evidence about the optimal force level in orthodontics could be extracted from literature. Well-controlled clinical studies and more standardized animal experiments in the orthodontic field are required to provide more insight into the relation between the applied force and the rate of tooth movement.     

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.     

Efficacy of piezocision on accelerating orthodontic tooth movement: A systematic review

Objectives:The aim of this systematic review was to evaluate the effect of piezocision as an adjunctive procedure to accelerate orthodontic tooth movement.Materials and Methods:Randomized controlled trials and controlled clinical trials that investigated the effectiveness of piezocision on accelerating orthodontic tooth movement were identified through electronic and manual searches. The literature search, study inclusion, risk of bias assessment, and data extraction were performed by two reviewers independently.Results:Four eligible studies were included in this review. All studies reported accelerated tooth movement after piezocision, and three reported a significant reduction of treatment duration in the piezocision group. No deleterious effects on periodontal status, pain perception, satisfaction, root resorption, or anchorage control were reported in any studies.Conclusion:Based on currently available information, weak evidence supports that piezocision is a safe adjunct to accelerate orthodontic tooth movement, at least in the short term. More high-quality clinical trials to determine the long-term effects and optimal protocol for piezocision are needed to draw more reliable conclusions.     

Efficacy of clear aligners in controlling orthodontic tooth movement: A systematic review

Objective:To assess the scientific evidence related to the efficacy of clear aligner treatment (CAT) in controlling orthodontic tooth movement.Materials and Methods:PubMed, PMC, NLM, Embase, Cochrane Central Register of Controlled Clinical Trials, Web of Knowledge, Scopus, Google Scholar, and LILACs were searched from January 2000 to June 2014 to identify all peer-reviewed articles potentially relevant to the review. Methodological shortcomings were highlighted and the quality of the studies was ranked using the Cochrane Tool for Risk of Bias Assessment.Results:Eleven relevant articles were selected (two Randomized Clinical Trials (RCT), five prospective non-randomized, four retrospective non-randomized), and the risk of bias was moderate for six studies and unclear for the others. The amount of mean intrusion reported was 0.72 mm. Extrusion was the most difficult movement to control (30% of accuracy), followed by rotation. Upper molar distalization revealed the highest predictability (88%) when a bodily movement of at least 1.5 mm was prescribed. A decrease of the Little''s Index (mandibular arch: 5 mm; maxillary arch: 4 mm) was observed in aligning arches.Conclusions:CAT aligns and levels the arches; it is effective in controlling anterior intrusion but not anterior extrusion; it is effective in controlling posterior buccolingual inclination but not anterior buccolingual inclination; it is effective in controlling upper molar bodily movements of about 1.5 mm; and it is not effective in controlling rotation of rounded teeth in particular. However, the results of this review should be interpreted with caution because of the number, quality, and heterogeneity of the studies.     

Influence of nicotine on orthodontic tooth movement: A systematic review of experimental studies in rats

ObjectiveThe objective of this systematic review was to assess the impact of nicotine administration on orthodontic tooth movement (OTM).MethodsA systematic search was conducted in PubMed, Scopus, EMBASE, MEDLINE (OVID) and Web of Knowledge databases and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Studies evaluating the influence of nicotine on OTM, and with the presence of a control group (OTM without nicotine administration), were included. Quality assessment of the selected studies was performed following the Animal Research Reporting in Vivo Experiment (ARRIVE) guidelines.ResultsSix of the initially identified 108 articles fulfilled the inclusion criteria and were selected. All included studies were performed in male rats, which underwent OTM with or without nicotine administration. Since there was a variation among the included studies regarding nicotine dosage and the duration and magnitude of force application during OTM only a qualitative analysis could be performed. The studies reported that nicotine administration accelerated OTM by inducing alveolar bone resorption around the moving teeth. It was also found that nicotine increased root resorption during experimental OTM. More standardized animal research or clinical studies are warranted to further evaluate the impact of nicotine on OTM.ConclusionsOn an experimental level, nicotine exposure in rats jeopardizes OTM by increasing alveolar bone loss and root resorption. From a clinical perspective, further studies are needed to assess the impact of habitual use of tobacco products on OTM.     

Effectiveness of non-conventional methods for accelerated orthodontic tooth movement: A systematic review and meta-analysis

Objectives

To assess the available evidence on the effectiveness of accelerated orthodontic tooth movement through surgical and non-surgical approaches in orthodontic patients.

Methods

Randomized controlled trials and controlled clinical trials were identified through electronic and hand searches (last update: March 2014). Orthognathic surgery, distraction osteogenesis, and pharmacological approaches were excluded. Risk of bias was assessed using the Cochrane risk of bias tool.

Results

Eighteen trials involving 354 participants were included for qualitative and quantitative synthesis. Eight trials reported on low-intensity laser, one on photobiomodulation, one on pulsed electromagnetic fields, seven on corticotomy, and one on interseptal bone reduction. Two studies on corticotomy and two on low-intensity laser, which had low or unclear risk of bias, were mathematically combined using the random effects model. Higher canine retraction rate was evident with corticotomy during the first month of therapy (WMD = 0.73; 95% CI: 0.28, 1.19, p < 0.01) and with low-intensity laser (WMD = 0.42 mm/month; 95% CI: 0.26, 0.57, p < 0.001) in a period longer than 3 months. The quality of evidence supporting the interventions is moderate for laser therapy and low for corticotomy intervention.

Conclusions

There is some evidence that low laser therapy and corticotomy are effective, whereas the evidence is weak for interseptal bone reduction and very weak for photobiomodulation and pulsed electromagnetic fields. Overall, the results should be interpreted with caution given the small number, quality, and heterogeneity of the included studies. Further research is required in this field with additional attention to application protocols, adverse effects, and cost-benefit analysis.

Clinical significance

From the qualitative and quantitative synthesis of the studies, it could be concluded that there is some evidence that low laser therapy and corticotomy are associated with accelerated orthodontic tooth movement, while further investigation is required before routine application.     

Effect of pharmacological agents on relapse following orthodontic tooth movement:: A systematic review of animal studies

ObjectivesTo investigate and synthesize systematically the evidence from animal studies pertaining to the effect of pharmacological agents on tooth movement relapse following cessation of orthodontic force application.Materials and MethodsAn electronic search was conducted in seven online databases (including gray sources) without restrictions until the third week of April 2019, followed by a hand search in the reference lists of eligible articles. Controlled animal studies investigating the effect of pharmacological agents on tooth movement relapse following orthodontic treatment were selected. Relevant data were extracted from eligible studies and the risk of bias assessment was done using SYRCLE''s risk of bias tool. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation tool.ResultsThe search identified 2354 records, of which 7 studies were deemed eligible for inclusion in the qualitative synthesis, with the majority presenting an unclear risk of bias. Orthodontic relapse was shown to decrease with the administration of pamidronate disodium, atorvastatin, aspirin, and chemically modified tetracycline-3. Inconsistent effects on relapse were observed after the use of simvastatin. The overall quality of retrieved evidence was assessed as low at best.ConclusionsThe available evidence shows that the investigated pharmacological agents may demonstrate variable effects on tooth movement relapse following cessation of orthodontic force. Additional evidence of higher quality is required to draw definitive conclusions on their effects and to make potential recommendations for clinical application.     

Effectiveness of adjunctive interventions for accelerating orthodontic tooth movement: a systematic review of systematic reviews

This study was aimed to summarise published systematic reviews (SRs) that assess the effects of adjunctive interventions on the acceleration of orthodontic tooth movement (OTM). Electronic and manual searches were performed up to August 2016. Systematic reviews investigating the impact of adjunctive techniques on the promotion of OTM were included. The methodological quality of the included reviews was evaluated using the A Measurement Tool to Assess Systematic Reviews (AMSTAR) scale. The quality of evidence for each intervention was assessed using GRADE. The Jadad decision algorithm was used to select a study to provide body evidence from discordant reviews on the same intervention. A total of 11 SRs were included in this study. AMSTAR scores ranged from 4 to 10 of 11. The quality of evidence ranged from very low to low. The short‐term (1–3 months) effects of low‐level laser therapy (LLLT, 5 and 8 J cm^?2) and corticotomy were supported by low‐quality evidence. The evidence regarding the efficacy of photobiomodulation, pulsed electromagnetic field, interseptal bone reduction, two vibrational devices (Tooth Masseuse and Orthoaccel) and electrical current was of very low quality. Relaxin injections and extracorporeal shock waves were reported to have no impact on OTM according to low‐ and very low‐quality evidence, respectively. Based on currently available information, we conclude that low‐quality evidence indicates that LLLT (5 and 8 J cm^?2) and corticotomy are effective to promote OTM in the short term. Future high‐quality trials are required to determine the optimal protocols, as well as the long‐term effects of LLLT and corticotomy, before warranting recommendations for orthodontics clinics.     

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。     

Invisalign矫治器牙齿移动效率的研究进展

无托槽隐形矫治器通过一系列透明的、可自行摘戴的透明塑料牙套来实现牙齿排齐,纠正错牙合畸形。但在矫治过程中,牙齿实际移位量与预期移位量间相比存在"滞后性",从而涉及矫治效率问题。本文就Invisalign矫治器在各种类型牙齿移动(伸长、压低、扭转、倾斜、扩弓、推磨牙向后等)中的效率进行综述,为临床医生选择合适的Invisalign病例以及设计无托槽隐形矫治方案提供指导。     

The effectiveness of locally injected platelet-rich plasma on orthodontic tooth movement acceleration:: A systematic review of animal studies

ObjectivesTo critically appraise the current evidence available from animal studies pertaining to the effectiveness of platelet-rich plasma (PRP) in accelerating orthodontic tooth movement.Materials and MethodsElectronic searches of nine databases were conducted up to June 2020, followed by a hand search of the reference list of eligible studies. The study design required was prospective controlled animal studies. The primary outcome assessed was the rate of orthodontic tooth movement. The secondary outcome evaluated was histological changes after PRP application. Following study retrieval and selection, relevant data were extracted. Risk-of-bias (RoB) assessment was done using the Systematic Review Center for Laboratory Animal Experimentation''s Risk of Bias Tool (SYRCLE''s Risk of Bias Tool). Two review authors conducted the work of searching, study selection, and quality assessment independently and in duplicate.ResultsOf 193 studies, 5 animal studies were included in this systematic review. Three studies found a positive correlation between PRP injection and tooth movement acceleration, along with corresponding histological changes. Two studies detected no significant difference in tooth movement rate after PRP application.ConclusionsBased on the current limited evidence, the efficacy of PRP on tooth movement acceleration remains debatable. More well-designed randomized controlled trials involving humans are called for to obtain more clinically significant conclusions.     

The role of osteocytes during experimental orthodontic tooth movement: A review

ObjectiveTo explore the types of orthodontic force-induced mechanical stimuli that regulate osteocyte function.DesignIn orthodontics, a tooth can be moved through the alveolar bone when an appropriate orthodontic force is applied. These mechanical loads stimulate cells within the bone tissue around the tooth. These cellular responses lead to bone resorption on the side of the tooth where the pressure has been applied and bone deposition on the side of the tooth experiencing tension. Recently, osteocytes were identified to function as mechano-sensory cells in bone tissue that direct bone resorption and bone formation. Based on recent literature, the proposed function of osteocytes during orthodontic tooth movement is explored with better understanding.ResultsSeveral stimuli regulating osteocyte function have been highlighted, and their potential roles in events initiating osteocyte sensing of orthodontic force have been explored in detail. The most popular hypotheses for osteocyte response include stress-induced bone matrix deformation/microcrack formation and fluid-flow shear stress.ConclusionsUnderstanding osteocyte function under mechanical stress may have profound implications in future orthodontic treatments.     

有关正畸牙移动力学作用的研究进展

正畸治疗通过对牙齿施加矫治力使牙齿移动.近年来,随着新材料新技术应用,正畸的加力方式在改变,正畸的治疗理念在改变.本文将矫治和矫形力学研究进展,以及新材料新技术包括自锁托槽、微种植体、手术辅助正畸和无托槽隐形矫治等影响矫治力学的研究进展作一综述.     

The effect of osteoporosis on periodontal status, alveolar bone and orthodontic tooth movement. A literature review

Osteoporosis, an age-related condition, is defined as a systemic skeletal disease characterized by low bone mass and micro-architectural deterioration with a consequent increase in bone fragility and susceptibility to fracture. It is considered the most common bone metabolic disease and it constitutes a major public health problem. Several studies indicate that osteoporosis may be related to decreased oral bone density and alveolar bone loss. In osteoporotic patients, uncoupling of bone resorption and bone formation has taken place. Both bone resorption and bone formation are accelerated, and excessive bone resorption usually leads to loss of attachment. Osteoporosis could also affect the rate of tooth movement through the involvement of alveolar bone. In healthy individuals, bone is constantly being remodeled in the coupled sequence of bone resorption and formation. When a force is applied to a tooth, alveolar bone formation and resorption occur predominantly on the tension and pressure sides of the root, respectively, and the tooth moves with increased alveolar bone remodeling. Experimental studies suggest that systemic-osteoporotic hormone imbalance increases bone turnover and accelerates tooth movement while under orthodontic treatment. Based on these observations it can be concluded that deviations in bone turnover and consequent periodontal problems influence the response to orthodontic forces, and this should be taken into consideration when planning orthodontic treatment in adult patients with metabolic bone disease, especially postmenopausal females or those on chronic medication affecting bone metabolism.     

Effect of platelet-rich plasma on the rate of orthodontic tooth movement:: A split-mouth randomized trial

ObjectiveTo investigate the effect of local injection of platelet-rich plasma (PRP) on the rate of orthodontic tooth movement.Materials and MethodsSixteen female patients were randomly allocated in a split-mouth study design to receive PRP injections with CaCl₂ activating solution on one side (intervention side) while the other side received CaCl₂ injection only (control side). Canine retraction was performed on 0.017 × 0.025-inch stainless steel archwire applying 1.5 N retraction force. PRP and CaCl₂ injections were done at 0, 3, and 6 weeks. The duration of the study was 4 months. Data were collected from digitized models. Assessment of pain accompanying the procedure was done using a visual analogue scale.ResultsThe rate of canine retraction was faster on the intervention side in the first 2 months, with a statistically significant difference in the first month (P = .049). On the other hand, the rate was statistically significantly slower on the intervention side in the third month following cessation of PRP injections (P = .02). Pain increased following injections on both sides.ConclusionsPRP showed a positive potential to accelerate the rate of tooth movement when injected in the first 2 months. Repeated injections of PRP to maintain a steady rate of accelerated tooth movement warrant further investigation.