Anterior open bite correction via molar intrusion: Diagnosis, advantages, and complications.

Anterior open bite can be effectively treated nonsurgically via molar intrusion. This technique, involving the intrusion of posterior teeth using temporary skeletal anchorage devices, prompts counterclockwise rotation of the mandible. This rotation not only corrects anterior open bite but also contributes to a decrease in anterior facial height, improvements in lip incompetency, and forward movement of the chin. For successful outcomes, temporary skeletal anchorage devices, installed on both the buccal and palatal sides, must deliver equivalent intrusion force to the maxillary teeth. Treatment planning should consider factors such as skeletal discrepancies, vertical excess, incisor exposure, and configuration of the occlusal plane. Clinicians are advised to closely monitor periodontal changes and consider overcorrection to ensure lasting stability and maintenance of incisal overlap post-treatment.

Cortical bone microdamage affects primary stability of orthodontic miniscrew.

BACKGROUND: The aim of this study was to investigate the effects of orthodontic miniscrew pitch and thread shape on microdamage in cortical bone. The relationship between the microdamage and primary stability was also examined. METHODS: Ti6Al4V orthodontic miniscrews and 1.0-mm-thick cortical bone pieces from fresh porcine tibia were prepared. The orthodontic miniscrews had custom-made thread height (H) and pitch (P) size geometries, and were classified into three groups: control geometry; HCPC (HC; thread height = 0.12 mm, PC; pitch size = 0.60 mm), geometry with a narrower pitch; HCPN (HC; thread height = 0.12 mm, PN; pitch size = 0.30 mm), and geometry with a taller thread height; HTPC (HT; thread height = 0.36 mm, PC; pitch size = 0.60 mm). The orthodontic miniscrews were inserted into a pilot hole in the cortical bone, and maximum insertion torque and Periotest value were measured. After insertion, the samples were stained with basic fuchsin. Histological thin sections were obtained and the bone microdamage parameters, i.e., total crack length and total damage area, and insertion state parameters, i.e., orthodontic miniscrew surface length and bone compression area were calculated. RESULTS: The orthodontic miniscrews with the taller thread height resulted in lower primary stability with minimal bone compression and microdamage; however, the narrower thread pitch led to maximum bone compression and extensive bone microdamage. CONCLUSIONS: A wider thread pitch reduced microdamage, and decreased thread height resulted in increased bone compression, ultimately resulting in increased primary stability.

Periodontal status following orthodontic mini-screw insertion: A prospective clinical split-mouth study.

BACKGROUND: Anchorage control is one of the most important determinants of orthodontic treatments. Mini-screws are used to achieve the desired anchorage. Despite all their advantages, there is a possibility that treatment will not be successful due to conditions related to their interaction with the periodontal tissue. OBJECTIVE: To evaluate the status of the periodontal tissue at the sites adjacent to the orthodontic mini-implants. METHODS: A total of 34 teeth (17 case and 17 control) in 17 orthodontic patients requiring a mini-screw in the buccal area to proceed with their treatment were included in the study. Oral health instruction was provided to the patients prior to the intervention. In addition, scaling and root planing of the root surface were done using manual instruments and ultrasonic instruments if needed. For tooth anchorage, a mini-screw with Elastic Chain or Coil Spring was used. The following periodontal indices were examined in the mini-screw receiving tooth and the contralateral tooth: plaque index, pocket probing depth, attached gingiva level (AG), and gingival index. Measurements were made before the placement of the mini-screws and 1, 2, and 3 months following that. RESULTS: The results revealed a significant difference only in the amount of AG between the tooth with mini-screw and the control tooth (p = 0.028); for other periodontal indices, there were no significant differences between the two groups. CONCLUSION: This study showed that periodontal indices in adjacent teeth of the mini-screws do not change significantly compared to other teeth and mini-screws can be used as a suitable anchorage without posing a threat to the periodontal health. Using mini-screws is a safe intervention for orthodontic treatments.

Revisiting the Complications of Orthodontic Miniscrew.

Miniscrew has been used widely as an effective orthodontic anchorage with reliable stationary quality, ease of insertion and removal techniques, immediate or early loading, flexibility in site insertion, less trauma, minimal patient cooperation, and lower price. Nonetheless, it is not free of complications, and they could impact not only the miniscrew success rate but also patients' oral health. In this article, literature was searched and reviewed electronically as well as manually to evaluate the complications of orthodontic miniscrew. The selected articles are analyzed and subcategorized into complications during and after insertion, under loading, and during and after removal along with treatment if needed according to the time. In addition, the noteworthy associated factors such as the insertion and removal procedures, characteristics of both regional and local anatomic structures, and features of the miniscrew itself that play a significant role in the performance of miniscrews are also discussed based on literature evidence. Clinicians should notice these complications and their related factors to make a proper treatment plan with better outcomes.

Miniscrews for orthodontic anchorage: analysis of risk factors correlated with the progressive susceptibility to failure.

INTRODUCTION: The phenomenon of orthodontic anchorage miniscrews loosening after being implanted several times happens in daily clinical practice, and the reasons need to be traced. This study aimed to investigate the underlying risk factors influencing the progressive susceptibility of orthodontic miniscrews to failure. METHODS: Overall, 889 miniscrews were successively inserted into 347 patients because some loosened or fell off once, twice, or more before achieving their purposes. The number of miniscrew failures (ie, once, twice, or more) was defined as progressive susceptibility to failure. The clinical indicators were assessed via univariate analysis, multicollinearity diagnosis, and Poisson log-linear regression model with stepwise calculation to screen out. RESULTS: The progressive susceptibility of miniscrews to failure was proved to be affected by the age of patients, the onset of force application, site of placement, and appliance type. Age and onset of force application presented a negative relationship with susceptibility. Miniscrews inserted in the palatal region appeared to be more stable than the forepart of the arch. In contrast, the retromaxillary and retromandibular areas obtained the lowest stability. The patients with fixed appliances were more unlikely to suffer progressive failure than removable appliances. In addition, the larger number of screws inserted in each patient, the greater probability of failure. CONCLUSIONS: Younger people with removable appliances that miniscrews inserted in the retromaxillary or retromandibular regions and earlier onsets of loading had a higher progressive susceptibility to loosening. Meanwhile, the failure rate was elevated with the increasing number of screws per patient received.

Novel digital technique to analyze the accuracy and intraoperative complications of orthodontic self-tapping and self-drilling microscrews placement techniques: An in vitro study.

INTRODUCTION: The objectives of this study were to analyze and compare the accuracy and intraoperative complications of orthodontic self-tapping and orthodontic self-drilling microscrew placement techniques. METHODS: A total of 60 orthodontic microscrews were randomly distributed into 2 study groups: (1) group A, orthodontic self-drilling microscrew placement technique (n = 30); and (2) group B, orthodontic self-tapping microscrew placement technique (n = 30). Cone-beam computed tomography and intraoral scans were performed before and after the orthodontic microscrew placement techniques and uploaded in 3-dimensional implant planning software to analyze the deviation angle and the horizontal deviation measured at the coronal entry point and apical endpoint between orthodontic microscrews planned and performed, using the Student t test. In addition, intraoperative complications, such as root perforations after the orthodontic microscrews placement and the fracture of the orthodontic self-tapping microscrews during their placement, were also analyzed. RESULTS: The paired t test revealed statistically significant differences at the apical endpoint (P <0.001) between planned and performed orthodontic self-tapping and self-drilling microscrew placement techniques. However, the paired t test revealed no statistically significant differences at the coronal entry point (P = 0.1047) and angular deviations (P = 0.3251) between planned and performed orthodontic self-tapping and self-drilling microscrews placement techniques. Furthermore, 4 root perforations were observed at the orthodontic self-tapping microscrews placement technique, and 1 orthodontic self-tapping microscrew was fractured during the placement procedure. CONCLUSIONS: The results show that the orthodontic self-drilling microscrew technique increases the accuracy of orthodontic microscrews placement, resulting in fewer intraoperative complications.

Orthodontic mini-implants: clinical and peri-implant evaluation.

The study evaluated the clinical changes of orthodontic mini-implants (MI) inserted for the purpose of anchoring during orthodontic treatment. The null hypotheses were: 1-that there is no correlation between proximity of the MI to the root and peri-implantitis or mobility; 2-that peri-implantitis does not interfere with mobility; 3-that the pain is not related to mobility or peri-implantitis. Forty (40) patients were selected and the MI were evaluated for each patient. MI in the upper and lower arch were evaluated for a period of approximately 6 months with relationship to the distance MI - root, peri-implantitis, mobility, biological damage and pain through the analysis of periapical radiography and clinical/periodontal evaluation. The evaluations were performed out by means of scores and a correlation was made between the variables. No statistically significant differences were found between the upper and lower arch in the variables evaluated, except for the mobility that was more present in the lower arch (p = 0.0336). There was a correlation between peri-implantitis and mobility (p = 0.0003) and between pain and mobility (p = 0.0443). However, there was no correlation between a greater degree of peri-implantitis and greater mobility (p = 0.7054). In addition, the MI placed too close to the root showed peri-implantitis (p = 0.0142). The null hypotheses were rejected because there was a positive correlation between the analyzes. The placement of MI close to the root led to greater peri-implantitis. Patients who reported pain had greater mobility of the MI and peri-implantitis led to greater mobility.

Spontaneous repair of iatrogenic root perforation by an orthodontic miniscrew: A case report.

BACKGROUND AND OVERVIEW: Orthodontic miniscrews have become popular tools for providing temporary anchorage during orthodontic treatment. Although they are easy to insert, damage to the periodontal ligament or dental root during insertion is an unfavorable iatrogenic complication. Root perforation during miniscrew insertion in human teeth has been reported in a few articles. In this article, the authors describe the spontaneous repair of an iatrogenic root perforation in a mandibular first molar that occurred during insertion of an orthodontic miniscrew in a young girl undergoing orthodontic treatment. CASE DESCRIPTION: A 15-year-old girl with malocclusion was undergoing orthodontic treatment when the mesial root of her mandibular right first molar was damaged by an orthodontic miniscrew. The miniscrew and corresponding bracket were immediately removed to avoid any unnecessary forces on the tooth. Because the pulp remained vital without any additional damage and infection for 6 months, orthodontic treatment was resumed and completed in 9 months without any pulp damage or unfavorable symptoms. Serial periapical radiographs and cone-beam computed tomographic images showed that the injured area was surrounded by reparative tissue without any apical lesion. CONCLUSIONS AND PRACTICAL IMPLICATIONS: The findings of this case suggest that immediate removal of unnecessary forces provides an environment for spontaneous repair in cases of iatrogenic root perforation by orthodontic miniscrews, even when the damage involves the pulp. If force stimulation is avoided for a certain period, which was 6 months in this case, it may be possible to complete the orthodontic treatment without unfavorable symptoms.

Efficacy and safety of micro-implant anchorage in Angle class II malocclusion orthodontic treatment: A protocol for systematic review and meta-analysis.

BACKGROUND: Angle class II malocclusion is clinically complex and common malocclusion type, which affects beauty. Conventional treatment has the disadvantages of long course of treatment, high cost, easy recurrence and limited curative effect. Clinical practice shows that micro-implant anchorage has certain advantages in the treatment of Angle II malocclusion, but lacks the evidence of evidence-based medicine. This study systematically evaluates the efficacy and safety of micro-implant anchorage in the treatment of Angle class II malocclusion. METHODS: A systematic search was performed by retrieving on English databases (PubMed, Embase, Web of Science, and the Cochrane Library) and Chinese databases (CNKI, Wanfang, Weipu [VIP], CBM). Besides, manually search for Google and Baidu academic of micro-implant anchorage in the treatment of Angle class II malocclusion in randomized controlled clinical research. The retrieval time limit was from the establishment of the database to September 2020. Two researchers independently extracted and evaluated the quality of the data in the included study. A meta-analysis was performed using RevMan5.3 software. RESULTS: In this study, the efficacy and safety of micro-implant anchorage against Angle class II malocclusion were evaluated by SNA, BNA, ANB, NLA°, Adverse reaction. CONCLUSIONS: This study will provide reliable evidence-based evidence for the clinical application of micro-implant anchorage in the treatment of Angle class II malocclusion. ETHICS AND DISSEMINATION: Private information from individuals will not be published. This systematic review also does not involve endangering participant rights. Ethical approval was not required. The results may be published in a peer-reviewed journal or disseminated at relevant conferences.OSF Registration number: DOI 10.17605/OSF.IO/UPBR8.

Adult orthodontic retreatment of severe root resorption by skeletal anchorage: A case report.

The presence of root resorption and its correlated factors are concerns that must be considered in orthodontic planning. This case report describes the orthodontic retreatment of a patient with a dental to facial midline discrepancy, a severe apical root resorption, and with maxillary and mandibular incisors presenting accentuated labial tipping and protrusion. The treatment included self-ligating brackets, maxillary unilateral distalization with skeletal anchorage and a mandibular extraction, followed by retraction. The orthodontic planning was based on simple and efficient mechanics and the treatment duration was of 19 months. Based on the acceptable final results it can be assumed that the treatment choices enabled a successful approach, maintaining a stable root condition.

Root changes in buccal versus palatal maxillary impacted canines of adults: A longitudinal and retrospective 3-dimensional study before and after orthodontic traction.

OBJECTIVE: Maxillary impacted canines (MIC) could suffer root changes after canine traction. The aim of this study was to evaluate the 3-dimensional root changes in buccal versus palatal MIC after orthodontic traction. MATERIALS AND METHODS: This longitudinal and retrospective study included pre-treatment and after traction cone beam computed tomography scans (CBCTs) of 30 subjects with unilateral/bilateral MIC. A total of 43 MIC were divided into 2 groups: buccal (n=17) or palatal (n=26). Root changes in length and area after orthodontic traction were measured at sagittal, coronal and axial sections. Intergroup comparison was carried out by t or U Mann-Whitney tests, depending on normality. Multiple linear regression analysis was used to evaluate the influence of all predictor variables on root changes (P<0.05). RESULTS: Significant difference between groups was found for root area changes in the upper limit of the cervical third at axial section that showed greater appositional values for the palatal impacted canine group (-1.18mm2) and resorptive values for the buccal impacted canine group (0.62mm2) (P=0.024). Position of impaction palatal influenced the increase of root area in the coronal section and in the upper limit of the cervical third at axial section. Age directly influenced the decrease of total length and root area in sagittal and coronal sections, respectively. CONCLUSION: Orthodontic traction of MIC produced an important appositional root change in the palatal impaction group in the axial root area of the upper limit of the cervical third. Impaction position and age influenced the increase and decrease of root area and length of some specific radicular regions.

Risk factors for orthodontic mini-implants in skeletal anchorage biological stability: a systematic literature review and meta-analysis.

The reason of the biological stability loss of mini-implants is still a matter of discussion between dentistry professionals. The main objective of this systematic literature review and meta-analysis was to analyze the risk factors that prejudice this loss. A search was made in the electronic databases Pubmed, Scopus, Embase and Cochrane, in addition a manual search was made too in Grey Literature (Opengrey). No limits were set on the year of publication or language. The inclusion criteria were: studies in humans treated with fixed appliances with mini-implants, where the risk factors for secondary stability were evaluated for a minimum of 8 weeks. After eliminating duplicate studies and assessing which ones achieve the inclusion criteria, a total of 26 studies were selected for the qualitative synthesis, 18 of them were included in the quantitative synthesis. Common risk variables were compared in all of them. Analyzing the forest and funnel plots, statistically significant differences were obtained only for location, the upper maxilla having lower risk than the mandible with an odds ratio of 0.56 and confidence interval of 0.39 to 0.80. Prospective studies under controlled conditions should be required in order to obtain a correct assessment of the variables analyzed.

Dentoalveolar Distraction Osteogenesis for Rapid Maxillary Canine Retraction: An Overview of Technique, Treatment, and Outcomes.

Patients and orthodontists seek to reduce treatment time in braces. Rapid canine retraction through dentoalveolar distraction osteogenesis is one of several treatment approaches to reduce treatment in braces. This article provides an overview of technique of dentoalveolar distraction osteogenesis to accomplish rapid canine retraction and associated outcomes. When this treatment protocol is implemented well, rapid canine retraction is achieved predictably with minimal side effects. Although current evidence suggests that adverse sequelae, such as root resorptions and pulp devitalization, are rare, prospective clinical studies that are adequately powered and documenting long-term follow-up of these outcomes are lacking.

Quantification of pro-inflammatory cytokines and osteoclastogenesis markers in successful and failed orthodontic mini-implants.

OBJECTIVES: Miniscrew has been frequently used, considering that anchorage control is a critical point in orthodontic treatment, and its failure, the main adverse problem. Using two groups of stable (successful) and unstable (failed) mini-implants, this in vivo study aimed to quantify proinflammatory cytokines IL-1 α, IL-6, IL-17, and TNF-α and osteoclastogenesis marker RANK, RANKL, and OPG in gingival tissue, using the real-time polymerase chain reaction technique. METHODOLOGY: Thirteen patients of both sexes (11-49 years old) under orthodontic treatment were selected, obtaining 11 successful and 7 failed mini-implants. The mini-implants were placed and removed by the same surgeon, in both jaws. The mean time of permanence in the mouth was 29.4 months for successful and 7.6 months for failed mini-implants. At removal time, peri-mini-implant gingival tissue samples were collected and processed for quantification of the proinflammatory cytokines and osteoclastogenesis markers. Nonparametric Wilcoxon rank-sum test considering the clusters and Kruskal-Wallis test were used for statistical analysis (α=0.05). RESULTS: No significant difference (p>0.05) was observed between the groups for either quantification of cytokines or osteoclastogenesis markers, except for IL-6 (p<0.05). CONCLUSIONS: It may be concluded that the expression of IL-1α, IL-17, TNF-α, RANK, RANKL, and OPG in peri-implant gingival tissue were not determinant for mini-implant stability loss, but the higher IL-6 expression could be associated with mini-implant failure.

Mini implants osseointegration, molar intrusion and root resorption in Sinclair minipigs.

AIM: The use of mini implants to create a passive intraoral anchorage point has been mainly tested in clinical trials. In this study, an experimental integrated approach evaluated mini implant loading protocols (immediate vs. delayed loading) on bone remodelling and mini implant stability and the consequent degree of dental intrusion and apical root resorption. METHODS: A total of 40 Absoanchor® mini implants with 1.2mm diameter and 8mm length were placed in a total of 5 minipigs, 8 per animal, 2 in each hemiarch. Each implant was attached through a lingual button to the vestibular side of the second and fourth premolars with a nitinol coil spring of 150g force. The analysis of morphological aspects included the degree of dental movement, mini implant stability, and new bone formation over the mini implant heads. Bone mini-implant interface and modifications of dental root in response to intrusion were studied by light and electron microscopy. RESULTS: The rate of mini implant success was>98%, mainly in those subjected to immediate loading. This loading protocol promoted a high degree of osseointegration along with a high degree of intrusive dental movement, particularly of the second premolars. However, the radiological and histological studies showed a low degree of root resorption. Associated with the high intrusive movement, the penetration of the root apexes produced an inner cortical surface deformation of the maxillary sinus floor by remodeling and bone growth. CONCLUSION: In minipigs immediate loading of smooth mini implants promoted a high degree of intrusive movement particularly of the second premolars, stimulated bone growth and osseointegration, but extensive root resorption was not observed.

[Archwire segmentation: a solution to the problems involved in treating atypical cases]. / La segmentation de l'arc, une réponse aux difficultés de traitement de cas atypiques.

INTRODUCTION: Asymmetrical orthodontic cases frequently prove very difficult to correct. Anchorage mini-screws are often needed to treat these cases when the malocclusion is of maxillary origin. Nonetheless, a precise biomechanical assessment must be made to avoid undesirable sideeffects resulting from the mechanics used. Whether one uses a continuous or a segmented archwire, adverse events can occur and must be planned for in order to contain them. MATERIALS AND METHODS: The authors will first give an overview of the possible undesirable effects using the continuous arch technique and the principles underlying the segmented archwire technique. Various clinical cases will also be described to support their argument. CONCLUSION: The advantage of the segmented techniques lies in the precision and speed of the movements obtained in the three dimensions of space. However, they can also present major drawbacks. In practice, these techniques seem best-suited to complex atypical cases, and particularly cases involving asymmetry of the frontal and transverse planes.

Finite Element Analysis of Stress in Maxillary Dentition during En-masse Retraction with Implant Anchorage.

The goal of this study was to investigate how the height of the archwire hook and implant anchor affect tooth movement, stress in the teeth and alveolar bone, and the center of resistance during retraction of the entire maxillary dentition using a multibracket system. Computed tomography was used to scan a dried adult human skull with normal occlusion. Three-dimensional models of the maxillary bone, teeth, brackets, archwire, hook, and implant anchor were created and used for finite element analysis. The heights of the hook and the implant anchor were set at 0, 5, or 10 mm from the archwire. Orthodontic force of 4.9 N was systematically applied between the hook and the implant anchor and differential stress distributions and tooth movements observed for each traction condition. With horizontal traction, the archwire showed deformation in the superior direction anterior to the hook and in the inferior direction posterior to the hook. Differences in traction height and direction resulted in different degrees of deformation, with biphasic movement clearly evident both in front of and behind the hook. With horizontal traction of the hook at a height of 0 mm, all the teeth moved distally, but not with any other type of traction. At a height of 5 mm or 10 mm, deformation showed an increase. The central incisor showed extrusion under all traction conditions, with the amount showing a reduction as the height of horizontal or posterosuperior traction increased. The center of resistance was located at the root of the 6 anterior teeth and entire maxillary dentition. The present results suggest that it is necessary to consider deformation of the wire and the center of resistance during en-masse retraction with implant anchorage.

Cytotoxicity of orthodontic temporary anchorage devices on human periodontal ligament fibroblasts in vitro.

Objectives: The objective of this study is to test cytotoxicity of four brands of commercially available orthodontic temporary anchorage devices (TADs). Setting and sample population: Twenty-four (six for each brand, i.e., Aarhus [AO]; Dual top [RMO]; Vector TAS [ORMCO]; and Unitek TAD [3M UNITEK]) TADs were tested. Materials and methods: Twenty-four (six for each brand, i.e., Aarhus [AO]; Dual top [RMO]; Vector TAS [ORMCO]; and Unitek TAD [3M UNITEK]) TADs were individually incubated in complete cell culture medium and shaken at a rate of 1.5 rpm at 37°C for 30 days to extract possible toxic substances in conditioned media (CM). To test cytotoxicity, human periodontal ligament fibroblasts were cultured and exposed to the CM for 24 hr, followed by the examinations of morphological changes, cell viability (MTT assay), and cell damage (lactate dehydrogenase [LDH] assay). Results: No morphological changes were observed in any of the four brands of TADs compared with the negative control. LDH assay showed that none of the four brands of TADs caused significant cell damage after CM treatment compared with the negative control (P > .05). No significant differences were found between any of the four brands of TADs (P > .05). MTT assay showed similar results as did the LDH assay, except for a statistically significant difference found in the TADs from 3M UNITEK compared with the negative control (P = .047). Conclusions: According to the International Standard Organization standards, except for the TAD from 3M, none of the other three brands of commercially available TADs (from AO, RMO, and ORMCO) exhibited significant cytotoxicity, suggesting their safe clinical applications.

Sagittal skeletal correction using symphyseal miniplate anchorage systems : Success rates and complications.

OBJECTIVES: Aim of this study is to evaluate success rates and complications related with symphyseal miniplate anchorage systems used for treatment of Class 2 and Class 3 deformities. METHODS: A total of 58 miniplates applied to 29 growing patients were evaluated. The first group comprised 24 symphyseal miniplates applied to 12 patients and Forsus Fatigue Resistant Devices were attached to the head of the miniplates for mandibular advancement. The second group consisted of 34 symphyseal miniplates applied to 17 patients and intermaxillary elastics were applied between acrylic appliances placed on the maxillary dental arch and the symphyseal miniplates for maxillary protraction. Success rate and complications of the symphyseal plate-screw anchorage system were evaluated. RESULTS: The overall success rate of symphseal miniplates was 87.9%. Six miniplates showed severe mobility and 2 miniplates broke during orthodontic treatment. Infection, miniplate mobility and mucosal hypertrophy were statistically different between the two groups. CONCLUSIONS: Symphyseal miniplates were generally used as successful anchorage units in most patients. Infection, mobility, and mucosal hypertrophy occurred more frequently in Class 2 deformity correction. However, the success rates regarding the two treatment modalities were comparable.

Influence of impacted maxillary canine orthodontic traction complexity on root resorption of incisors: A retrospective longitudinal study.

INTRODUCTION: The orthodontic traction of impacted canines is a procedure of variable complexity. The objective of this study was to determine the influence of this complexity on the root resorption (RR) of adjacent incisors, using cone-beam computed tomography. METHODS: This longitudinal retrospective study included 45 patients (19 female, 11 male; ages, 18.16 ± 7.3 years) with maxillary impacted canines, classified into 2 groups according to the level of orthodontic traction complexity: low complexity group (n = 20) and high complexity group (n = 25). The amounts of RR of 45 maxillary central and 45 lateral incisors were evaluated before and after treatment. Complexity was defined considering impaction sector, eruption inclination angle, and canine position (palatal, buccal, or bicortical). Three orthodontists measured RR in each maxillary incisor. Independent t tests or Mann-Whitney U tests were used to compare resorption between groups depending on the normality of the data. A multiple linear regression was calculated to evaluate the influence of all variables on RR (α = 0.05). RESULTS: RR of maxillary incisors in the sagittal, coronal, and axial sections showed no significant differences between groups (P > 0.05). Independently of the groups, RR ranged approximately from 1 to 1.5 mm and from 3 to 4 mm2. RR was less than 2 mm2 in the axial sections. Multiple linear regression indicated no significant influence of orthodontic treatment complexity on RR. Male patients had more RR, specifically in the maxillary central incisors than female patients (P < 0.05). CONCLUSIONS: The complexity of orthodontic traction of impacted maxillary canines is not a risk factor for greater RR of maxillary incisors close to the impaction area.