Comparison of mesiodistal angulations of premolars and molars in anterior open bite subjects with different sagittal malocclusions: A retrospective study.

INTRODUCTION: Mesiodistal angulation of premolars and molars can be altered by forces of open bite malocclusion. The aim of this study was to compare the mesiodistal angulations of the posterior teeth in class I, II, and III individuals with anterior open bite (AOB) versus individuals with harmonious occlusion. METHODS: This comparative cross-sectional study used 299 lateral head radiographs of individuals with permanent dentition. There were 4 groups (harmonious occlusion [n=89], Class I open bite [OB] [n=75], Class II OB [n=66], and Class III OB [n=69]). Premolar (1UPM, 2UPM) and molar (1UM, 2UM) angulations were measured relative to the occlusal plane and the palatal or mandibular plane by a trained and calibrated evaluator. ANOVA and Scheffe tests were used for statistical analyses (P<0.05). RESULTS: The mesial angulation of the upper premolars showed greater angulation of between approximately 2° and 5° in the OB groups compared to the harmonious occlusion group (P<0.05). Only in the Class II OB group did the first and second upper molars show distal angulation in relation to the palatal plane (1UM 81.85°±5.42°; 2UM 75.32±7.4°) (P<0.05). The Class III OB group presented the greatest distal angulations of the lower premolars and molars (between 3° to 5° of difference, P<0.05) in relation to those of the harmonious occlusion group. CONCLUSIONS: The upper first premolars in all the AOB groups and the lower second premolars in the Class II OB group had greater mesioangulation. Additionally, the upper molars of the Class II OB group and the lower molars of the Class III OB group showed distoangulation compared with the molars in the group with harmonious occlusion.

Effect of the application of software on the volumetric and cross-sectional assessment of the oropharyngeal airway of patients with and without an open bite: A CBCT study.

BACKGROUND: Using different software to evaluate the airways, with different thresholds, but within the range for airway recognition, could yield different measurements in the same patient with or without craniofacial disharmony. OBJECTIVES: The aim of the present study was to compare the volume and the most constricted area (MCA) of the oropharynx in individuals with or without an open bite by using 2 software programs meant for cone-beam computed tomography (CBCT). MATERIAL AND METHODS: This comparative study included 60 cases selected from 137 CBCT scans obtained from individuals with the presence or absence of an open bite. Each group included adults of both genders - in total 30 women and 30 men - with a mean age of 27.57 ±11.85 years in the open bite group and 26.23 ±6.78 years in the control group. The oropharyngeal volume and MCA were measured with 2 three-dimensional (3D) software packages: Planmeca Romexis®; and Nemotec NemoStudio®. Two calibrated orthodontists trained in the use of the software made the measurements. Data was analyzed using Student's t tests for independent and paired samples (p < 0.05). RESULTS: In general, the oropharynx volume measurements obtained with the NemoStudio software were significantly higher than those obtained with Romexis (19,007.17 ±8005.79 mm3 and 17,823.47 ±7148.62 mm3, respectively) (p = 0.020). However, when the groups were analyzed separately, the measurements of the group with an open bite did not differ according to the software used (p = 0.352). The measurements of the MCA of the oropharynx were significantly higher when obtained with the NemoStudio software (MD (mean difference) = 19.02 mm2) (p = 0.005). In contrast, no difference in the MCA results for the 2 software packages was found in the open bite group (p = 0.728). CONCLUSIONS: The volumetric and cross-sectional measurements of the oropharyngeal airway, particularly in individuals without an open bite, were affected by the software used.

Accuracy of computer-assisted surgery in immediate implant placement: An experimental study.

Purpose: Computer-guided surgery has been increased in recent years. Nonetheless, few data are available on the validation of this technique for immediate implant placement. The purpose of this in vitro study was to evaluate the accuracy of computer-guided surgery in immediate implant placement. Materials and Methods: Cone-beam computed tomography scans (CBCTs) and virtual models were obtained of eight fresh pigs hemi-mandibles to perform the digital planning of implants placement. Fifteen implants were simulated, and surgical guides were designed to transfer the digital planning to the surgical procedure. Postsurgical CBCTs were performed to compare the position of the planned implants versus the real implant position. Paired t-test and the intra-class correlation coefficient (ICC) were used to assess the mean differences and correlations in each outcome variable evaluated twice by one experienced researcher. Furthermore, variations were compared with the results reported in the scientific literature using a one-sample t-test P < 0.05. Results: The measurements of the outcome variables (implants position at the neck and apex level and the angular deviation) showed significant reproducibility (mean difference-0.01 mm, 0.07 mm, and 0.30°, respectively, P > 0.05). The ICC values ranged from 0.888 to 0.949. Furthermore, the mean deviation was 1.43 mm at the implant neck, 2.19 mm at the apex, and 6.81° for the angular deviation. Similarly, significant differences (P < 0.05) were found at the neck and angular deviation when comparing the results with values reported in the literature. Conclusions: Although some variations were observed, they did not have a clinically significant impact. Therefore, computer-guided surgery could be satisfactorily used in immediate implants placement.

The Impact of Cone-beam Computed Tomography on Diagnostic Thinking, Treatment Option, and Confidence in Dental Trauma Cases: A Before and After Study.

INTRODUCTION: The aim of this study was to identify whether cone-beam computed tomographic (CBCT) imaging affects endodontists' diagnostic thinking, treatment option, and confidence in dental trauma cases. METHODS: Twelve endodontists reviewed 15 dental trauma cases with clinical histories and periapical radiography (PR) and answered questions regarding their diagnostic thinking and treatment decisions and their confidence in both. One month later, the same participants reviewed the same cases and answered similar questionnaires with the aid of CBCT imaging. A statistical analysis of their responses was conducted. RESULTS: Differences were observed in diagnostic thinking when using PR or CBCT imaging (P < .05), and the use of PR was associated with a higher number of "unsure" answers to questions about diagnoses. After reviewing periapical radiographic images, the approach most frequently endorsed was "don't start conventional endodontic treatment and order CBCT," whereas the most common decision made after analyzing the CBCT images was "start conventional endodontic treatment." Clinical interventions were proposed more often when participants evaluated the clinical case using CBCT imaging than when using PR (P < .05). The participants' degree of confidence in their diagnostic thinking was not different after analysis using PR or CBCT imaging (P > .05). However, there was a difference between PR and CBCT imaging in participants' confidence in their treatment decisions (P < .05). Participants who initially indicated a lack of confidence in their diagnosis or treatment option gained confidence when CBCT images were available. However, the inverse behavior was also observed for participants who were initially confident on the basis of PR (P < .05). Participants who decided to start treatment after CBCT analysis were less confident than when using PR (P < .05). CONCLUSIONS: In dental trauma cases, CBCT imaging influenced participants' diagnostic thinking and choice of treatment modality and affected their confidence in the decision-making process.

Exploring digital filters for internal root resorption: how can we improve the diagnosis of small lesions?

OBJECTIVES: This study aimed to evaluate the impact of enhancement filters in detecting small simulated internal root resorptions (IRR). METHODS:: Forty-two extracted human teeth were sectioned, connected, and stored in a dry human jaw and X-rayed with photostimulable phosphor plates (PSPs), composing the control group (CG). In the middle-third of the root canals, IRR lesions were simulated using Da Silveira protocol. Later, the specimens were X-rayed to create the test group (TG). All images acquired were exported with seven enhancement filters plus the original image. Three examiners used a five-point Likert scale to evaluate the images regarding the presence/absence of IRR. Diagnostic efficacy was assessed from sensitivity and specificity results. Comparison among filters was performed by using receiver operating characteristic (ROC) curve analysis. RESULTS:: Moderate values of Kappa interexaminer (0.403-0.620) and high values of Kappa intraexaminer (0.757-0.915) were observed. The best performance occurred in the CG (p < 0.05). Original images presented the greatest sensitivity and area under the ROC curve (0.595-0.750), while the Endo filter presented the greatest specificity (0.952). Inversion and Pseudo-3D images produced the greatest doubt in the diagnosis, significant for CG with the Pseudo-3D filter (p < 0.05). CONCLUSIONS:: The Original and 'Endo' filters should be chosen as it offers greater diagnostic ability and allows more confidence during the evaluation.

Three-dimensional changes in root angulation of buccal versus palatal maxillary impacted canines after orthodontic traction: A retrospective before and after study.

INTRODUCTION: The aim of this study was to three-dimensionally compare the root angulation changes after orthodontic traction of buccally versus palatally maxillary impacted canines (MICs). MATERIAL AND METHODS: This retrospective study included patients from a private dental office of both sexes, older than 12 years, with at least one unilateral or bilateral buccal or palatal MIC, no loss of permanent teeth, with complete apical closure at the beginning of traction, and with CBCTs taken at pretreatment (T0) and after orthodontic traction (T1). The sample was divided in two groups according to their impaction site: buccal versus palatal. In all the scans, the MIC was segmented and the root angulation changes after traction were evaluated. The assessment included the sigma angle (projected on the XZ plane or coronal tomographic view), the delta angle (projected on the XY plane or axial view) and the epsilon angle (projected on the YZ plane, or sagittal view). Intragroup comparisons were performed with Wilcoxon signed-rank tests. Intergroup comparisons were performed with t-tests or Mann-Whitney U tests. Finally, the influence of MIC characteristics on the measured angles were evaluated with multiple linear regression analyses (α=0.05). RESULTS: Thirty-three patients (16 men, mean age: 20.38; 17 women, mean age 18.37) with forty-five orthodontically treated MIC (19 buccal versus 26 palatal) were finally included. The palatal MICs showed greater mediolateral uprighting than the buccal MICs, root displacement towards the midsagittal plane, as demonstrated by the sigma angle (palatal group: 37.58±15.08°; buccal group: 29.17±31.15°; P=0.164) and delta (palatal group: -76.90±26.55°; buccal group: -30.56±41.67°; P<0.001)angle changes. The buccal MICs showed greater anteroposterior uprighting, anterior root displacement, as demonstrated by the epsilon angle (palatal group: -4.63±12.37°; buccal group: -25.96±17.79°; P<0.001). CONCLUSIONS: Mediolateral and anteroposterior root angulation show significant differences after traction between buccal and palatal MICs. Palatal MICs showed greater medial root displacement while buccal MICs showed greater anterior root displacement. This condition should be considered for better planning of traction and orthodontic finishing.

Changes in alveolar bone morphology after traction of buccally vs palatally unilateral maxillary impacted canines: A cone-beam computed tomography study.

INTRODUCTION: The objective of this study was to evaluate the 3-dimensional changes in alveolar bone morphology after traction of buccally vs palatally unilateral maxillary impacted canines (MIC). METHODS: Following a split-mouth model, 27 cone-beam computed tomography images of unilaterally MIC (14 palatally and 13 buccally) and 27 contralateral unimpacted controls were obtained before and after traction using nickel-titanium closed-coil springs and a rigid anchorage appliance. Alveolar bone height and width were measured in the axial, coronal, and sagittal slides by 3 calibrated orthodontists, taking into account the impaction characteristics. A t test was used to compare the 2 groups, and a paired t test was applied for intragroup comparisons (both sides). A multiple linear regression model was used to evaluate the influence of the predictor variables on alveolar bone dimensional changes. RESULTS: The alveolar height showed a significantly greater decrease in palatally MIC (2.09 to 2.79 mm) than buccally MIC (0.28 to 0.57 mm) (P <0.05) for all surfaces. However, the alveolar width increased similarly in both groups up to 1.36 mm. In general, the affected side had a more significant height loss and greater increases in alveolar width than the nonaffected side. Regression analysis indicated that buccally MIC and age decreased alveolar changes, whereas female sex increased alveolar changes (P <0.05). CONCLUSIONS: MIC traction with nickel-titanium closed-coil springs and heavy anchorage induces significant 3-dimensional changes in alveolar bone characterized by alveolar bone height decreases and cervical alveolar bone width increases. The height decrease is greater in palatally than in buccally MIC.

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.

Inter-premolar width changes related to the orthodontic traction of maxillary impacted canines in adolescents and young adults: A retrospective CBCT study.

OBJECTIVE: Maxillary canine impaction is directly associated with a narrow maxillary arch, mainly in the inter-premolar widths. This study compared the transverse changes at the level of maxillary premolars after traction of maxillary impacted canines (MICs) in adolescents and young adults through three main goals: to compare unilateral versus bilateral cases, to compare buccally versus palatally MIC cases, and to compare the affected versus non-affected side exclusively in the unilateral group. METHODS: This before and after CBCT study involved 45 MIC orthodontically tractioned until the occlusal plane with a standardized protocol. The sample was classified regarding the impaction type (unilateral versus bilateral), impaction location (palatal versus buccal) and the affected versus unaffected sides in the unilateral cases. MIC characteristics as impaction sector, height, and complexity of the traction, as well as α and ß angles, canine root length and area were measured. Moreover, cephalometric characteristics were also evaluated. Mann-Whitney U or Wilcoxon signed-rank tests and multiple regressions were applied (α=0.05). RESULTS: Maxillary inter-premolar widths (first or second) expanded approximately 3mm after traction of unilateral or bilateral MIC (P>0.05). Changes in hemi-arch widths between palatal (1.67mm) versus buccal (1.90mm) MIC were similar (P>0.05). In unilateral impaction, the transversal changes on the affected side were 2mm versus almost 1mm observed in the unaffected side (P<0.05). Finally, the multiple linear regressions were identified to the ANB angle, the impaction sectors and the distance from middle raphe to the cusp tip of MIC as influential variables. CONCLUSION: The maxillary inter-premolar widths increase after traction of MIC without differences between type or location of impaction. In addition, the transverse change in the affected side in unilateral MIC is greater than the unaffected side resolving the earlier transverse asymmetry.

Upper airways evaluation in young adults with an anterior open bite: A CBCT retrospective controlled and cross-sectional study.

OBJECTIVE: To compare the dimensions of the upper airway in young adults with anterior open bite versus matched individuals with an adequate overbite (control group) using different measurement approaches (linear, area, and volume measures). MATERIALS AND METHODS: The sample included 137 cone-beam computed tomographies (CBCTs) of young adults (74 men and 63 women) divided into two groups: 47 CBCTs of individuals (mean age 27.89) with open bite (overbite depth indicator (ODI) 56.84°±9.48° and Frankfort mandibular plane angle (FMA) 31.21°±6.44°) and 90 CBCTs of individuals (mean age 26.87) without an open bite (ODI 62.24°±9.47°, FMA 26.79°±5.81°). Two trained and calibrated orthodontists made all linear, area, and volume measurements on the CBCT records of the upper airways using Planmeca Romexis software. The Mann-Whitney U-test, chi-squared test, and multiple linear regression were applied. Significance was set at P<0.05. RESULTS: There were no differences in linear or volume measurements between groups, but there was a greater area in the open bite group (greater mean difference between groups 928.3 mm2) than the control group. No variable influenced nasopharyngeal airway volume, but ANB angle affected oropharyngeal airway volume (ß=-623.87) and total airway volume (ß=-651.48). CONCLUSIONS: Orthodontists should be aware that the airways diagnosis can vary depending on the measurement approach used, the volumetric method being the gold standard. The pharyngeal airway volume was similar in individuals with vs. without an open bite and is mainly influenced by ANB angle in both groups.

Can Cone-beam Computed Tomography Change Endodontists' Level of Confidence in Diagnosis and Treatment Planning? A Before and After Study.

INTRODUCTION: This study evaluated the influence of cone-beam computed tomography (CBCT) on endodondists' level of confidence in their diagnosis of endodontic cases and their treatment plans. METHODS: Twenty clinical cases with periapical radiographs and small-volume CBCT scans were classified according to the American Association of Endodontists guidelines. Information was provided on patient clinical history, and both extraoral and intraoral examinations were simulated. Fifteen endodontists filled out 2 questionnaires. In the first (Q1), the clinical description and a periapical radiograph were presented, followed by the questions. Thirty days later, they answered a second questionnaire (Q2) containing the same clinical description and CBCT. Their confidence in diagnosis and treatment planning was analyzed before and after receiving the tomographic images. Responses were recorded on a 5-point Likert scale, and the Wilcoxon test was used to investigate before and after levels of confidence in diagnosis and treatment planning. RESULTS: The CBCT images influenced confidence in diagnosis and treatment planning of endodontic cases classified as complex (Wilcoxon test; P ≤ .05). There was a substantial change in the treatment planned in both moderate and complex cases after CBCT. Case complexity did not affect the participants' decision to request complementary information through CBCT. CONCLUSIONS: In complex cases, CBCT increased endodontists' confidence to diagnose and plan treatment, when compared with periapical radiographs. Endodontists tended to recommend intervention when periapical images were supplemented with CBCT. CBCT proved to be an imaging method that influences endodontists' preoperative evaluation and treatment choice.

Changes in maxillary incisor inclination and position after traction of unilateral vs bilateral maxillary impacted canines in nonextraction treatment: A cone-beam computed tomography study.

INTRODUCTION: The aim of this study was to compare the inclination and position changes of maxillary incisors after traction of unilateral vs bilateral maxillary impacted canines in nonextraction orthodontic treatment. METHODS: This longitudinal and retrospective study evaluated 24 patients with impacted maxillary canines; 12 with unilateral impaction and 12 with bilateral impaction. All subjects had Angle Class I malocclusion and were orthodontically treated with a standardized traction protocol that did not include premolar extractions. Cone-beam computed tomographies were obtained before and after canine traction and the inclination and position of both maxillary central incisors were measured. Furthermore, dental arch, skeletal, and canine impaction characteristics were evaluated. Paired and independent t tests were used for intra and inter group comparisons, respectively. Multiple linear regressions were also used. RESULTS: After canine traction, a significant incisor labial inclination was observed in the bilateral group (10.41° right side, P = 0.008 and 12.79° left side, P = 0.001), while in the unilateral group, this was observed only on the nonaffected side (6.67°, P = 0.008). Furthermore, a significant protrusion of incisors was observed in the bilateral group (2.66 mm right side, P = 0.006, and 3.15 mm left side, P = 0.001) and in the nonaffected side of the unilateral group (1.74 mm, P = 0.022). Intergroup comparisons showed greater values of incisor labial inclination for the bilateral group when compared with the unilateral group, independently of the sides. CONCLUSIONS: Traction of maxillary impacted canines, in nonextraction treatment, produces greater labial inclination of maxillary incisors in bilateral cases and similar protrusion in both unilateral and bilateral cases. Unilateral impaction cases showed significant incisor inclination and protrusion in the nonaffected side. These treatment effects should be considered by clinicians.

Root and alveolar bone changes in first premolars adjacent to the traction of buccal versus palatal maxillary impacted canines.

OBJECTIVE: To compare the root and alveolar bone changes in first premolars adjacent to the orthodontic traction of buccal versus palatal maxillary impacted canines (MIC). MATERIALS AND METHODS: Before and after traction, cone beam tomographic computed (CBCTs) of 25 subjects with unilateral/bilateral MIC were included in this follow-up and retrospective study. Thirty-six first premolars were divided into 2 groups, buccal (n = 15) or palatal (n = 21) MIC, and the tomographic images were evaluated before and after orthodontic traction. Root changes in length and area were measured in sagittal, coronal and axial sections. Dimensions of alveolar bone were evaluated in coronal sections. Intergroup and intragroup comparisons were performed using t or Mann-Whitney U tests. Multiple linear regressions analyses were used to evaluate the influence of all predictor variables on root and alveolar bone changes (P<0.05). RESULTS: Root and alveolar bone changes produced by orthodontic traction were not significant between groups. Root changes were smaller than 1 mm (length) and 2.51 mm2 (area). Alveolar bone changes between buccal and palatal MIC groups ranged from 0.13 mm to 1.69 mm Furthermore, the multivariate analysis showed no significant influence of the impaction condition (buccal or palatal) on root change. Nevertheless, some different predictor variables of the MIC influence these changes. In the alveolar bone, the maximum upper alveolar width (MUAW) is the most affected by the traction of the MIC. CONCLUSIONS: Orthodontic traction of buccal vs palatal MIC produces similar resorptive and appositional root and alveolar bone changes in the adjacent first premolars, without clinical relevance.

Midpalatal suture maturation stage assessment in adolescents and young adults using cone-beam computed tomography.

BACKGROUND: The aim of this study was to evaluate the midpalatal suture maturation stages in adolescents and young adults using cone-beam computed tomography (CBCT). METHODS: The sample comprised 200 CBCT scans of individuals aged 10 to 25 years old (95 males and 105 females) divided into three groups, adolescents (n = 48), post-adolescents (n = 52), and young adults (n = 100). The Planmeca ProMax 3D software was used for the midpalatal suture maturation stage evaluation according to Angieleri's method, using cross-sectional axial slice. Two previously calibrated examiners analyzed the images and classified according to five different maturation stages. A, B, and C stages were considered with open midpalatal suture, and D and E were considered without open midpalatal suture. Association tests were performed using chi-square test also, and a binary logistic regression was evaluated (P < 0.05). RESULTS: The possibility to find open midpalatal suture in individuals of 10 to 15 years old was 70.8%, in subject aged 16 to 20 and 21 to 25 years old was 21.2% and 17%, respectively. Furthermore, this possibility in individuals older than 16 years was greater in males than in females. CONCLUSIONS: The possibility to find open midpalatal suture in post-adolescents and young adults is greater than the orthodontists considered years ago. Furthermore, men are more likely to find midpalatal suture opening. These implications might be considered by the orthodontists when maxillary expansion is required. Besides, the ossification of the middle palatal suture is very variable, and therefore, the use of CBCT might be recommended to clarify this possibility.

Influence of maxillary canine impaction characteristics and factors associated with orthodontic treatment on the duration of active orthodontic traction.

INTRODUCTION: Orthodontic traction of a maxillary impacted canine (MIC) increases the orthodontic treatment time. Therefore, the objective of this study was to evaluate the influence of MIC characteristics and factors associated with orthodontic treatment on the duration of active orthodontic traction. METHODS: This follow-up and retrospective study included 45 MICs orthodontically tractioned into the occlusal plane with the use of a standardized protocol. MIC characteristics, including type, sector, side, location, height, and complexity of impaction, as well as α and ß angles and canine root length and area were measured. Likewise, factors associated with orthodontic treatment, including sex, age, malocclusion, premolar extractions, previous incisor root resorption, ANB, APDI, and SNA angles, and PNS-ANS distance were also evaluated. The statistical analysis included multiple linear regressions to estimate the influence of all variables on the duration of traction (α = 0.05). RESULTS: Sex had significant influence (P = 0.027) on the time of traction; in female patients, the time was 2.05 months more than in male patients. Bilateral impaction treatment increased the time by 2.74 months compared with unilateral cases (P = 0.001). Traction of bicortically centered impacted canines increased the duration of traction by 2.85 months (P = 0.001). Finally, the traction time increased in 2.35 months (P = 0.046) when the impaction sectors were 4 or 5 (close to the midline). CONCLUSIONS: The duration of active orthodontic traction of MIC is mainly influenced by sex, bilateral type, bicortically centered location, or when MIC is located in sector 4 or 5 close to midline, increasing the traction time by some months.

Three-dimensional evaluation of the root resorption of maxillary incisors after the orthodontic traction of bicortically impacted canines: case reports.

BACKGROUND: The root resorption of the maxillary incisors after the orthodontic traction of impacted canines is a concern for clinicians. The aim of this case series report was to evaluate the root resorption of the maxillary incisors after traction until the occlusal plane of the bicortically impacted canines (placed between the two cortical bones in the middle of the alveolar process) located in a complex position using three-dimensional superimposition. This case series report describes the root resorption of the maxillary incisors after orthodontic traction with NiTi closed coil springs and a heavy anchorage appliance in three cases of bilateral impacted canines located in a complex position (bicortically) near to midline. Cone-beam computed tomographies (CBCTs) were obtained before and after traction. Root resorption in all root surfaces of the maxillary incisors was evaluated with color-coded maps using the ITK-SNAP and the 3D Slicer software to indicate loss of the root surface (in red) or gain of the surface (in blue) and was quantified in millimeters by the superimposition method. RESULTS: The root changes mainly occurred in the apical third of the maxillary incisor root and did not exceed 2 mm. CONCLUSIONS: Root resorption of the maxillary incisors after the traction of bicortically impacted canines located in a complex position was observed mainly in the apex region, and the amount of root resorption was smaller than 2 mm in all root surfaces.

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.