Reliability of Artificial Intelligence-based Cone Beam Computed Tomography Integration with Digital Dental Images.

This study aimed to introduce cone-beam computed tomography (CBCT) digitization and integration of digital dental images (DDI) based on artificial intelligence (AI)-based registration (ABR) and to evaluate the reliability and reproducibility using this method compared with those of surface-based registration (SBR). This retrospective study consisted of CBCT images and DDI of 17 patients who had undergone computer-aided bimaxillary orthognathic surgery. The digitization of CBCT images and their integration with DDI were repeated using an AI-based program. CBCT images and DDI were integrated using a point-to-point registration. In contrast, with the SBR method, the three landmarks were identified manually on the CBCT and DDI, which were integrated with the iterative closest points method. After two repeated integrations of each method, the three-dimensional coordinate values of the first maxillary molars and central incisors and their differences were obtained. Intraclass coefficient (ICC) testing was performed to evaluate intra-observer reliability with each method's coordinates and compare their reliability between the ABR and SBR. The intra-observer reliability showed significant and almost perfect ICC in each method. There was no significance in the mean difference between the first and second registrations in each ABR and SBR and between both methods; however, their ranges were narrower with ABR than with the SBR method. This study shows that AI-based digitization and integration are reliable and reproducible.

Comparison of posttreatment stability after total mandibular arch distalization with mini-implants and mandibular setback surgery.

OBJECTIVES: To compare posttreatment stability in skeletal Class III patients between those treated by total mandibular arch distalization (TMAD) with buccal mini-implants and those by mandibular setback surgery (MSS). MATERIALS AND METHODS: The samples included 40 Class III adults, 20 treated by TMAD using buccal interradicular mini-implants and 20 treated with MSS. Lateral cephalograms were taken at pretreatment, posttreatment, and at least 1-year follow-up, and 24 variables were compared using statistical analysis. RESULTS: Mandibular first molars moved distally 1.9 mm with intrusion of 1.1 mm after treatment in the TMAD group. The mandibular incisors moved distally by 2.3 mm. The MSS group exhibited a significant skeletal change of the mandible, whereas the TMAD group did not. During retention, there were no skeletal or dental changes other than 0.6 mm labial movement of the mandibular incisors (P < .05) in the MSS group. There was 1.4° of mesial tipping (P < .01) and 0.4 mm of mesial movement of the mandibular molars and 1.9° of labial tipping (P < .001) and 0.8 mm of mesial movement of the mandibular incisors in the TMAD group. These dental changes were not significantly different between the two groups. CONCLUSIONS: The TMAD group showed a slightly decreased overjet with labial tipping of the mandibular incisors and mesial tipping of the first molars during retention. Posttreatment stability of the mandibular dentition was not significantly different between the groups. It can be useful to plan camouflage treatment by TMAD with mini-implants in mild-to-moderate Class III patients.

Comparison of Posttreatment Stability Between Mandibular Setback Surgery-Early and Conventional Surgery in Class III Patients: A 4.6-Year Follow-Up.

OBJECTIVES: This retrospective study aims to compare long-term stability between the mandibular setback surgery-early (MSE) approach, involving minimal orthodontics, and the mandibular setback conventional surgery (MCS) approach, involving sufficient orthodontics, in Class III patients with mandibular prognathism. METHODS: Among 210 patients who underwent orthognathic surgery, a total of 40 subjects were enrolled based on standardized inclusion criteria: only mandibular surgery, <5 mm setback difference between right and left of the mandible, orthodontics with fixed appliances, and more than 2 years of follow-up after treatment. These patients were allocated to the MSE (n = 20) and MCS groups (n = 20) according to the duration of presurgical orthodontics. Changes in cephalometric measurements were compared between the MSE and MCS groups before surgery (T0), 1 month after surgery (T1), at the end of treatment (T2), and posttreatment retention (T3). RESULTS: The MSE and MCS groups had a mean presurgical orthodontic duration of 2 and 9.5 months, respectively. From T1 to T2, the MSE group showed a significantly larger forward movement of the mandible than the MCS group (2.1 versus 0.7 mm; P < 0.001). In addition, from T2 to T3 (average 4.6 years), the MSE group presented anterior relapse of 0.6 mm in the mandible, but there were no statistically significant intergroup differences. CONCLUSION: Although the MSE group showed greater postsurgical forward mandibular relapse than the MCS group, the two groups exhibited similar skeletal and dental stability during the posttreatment retention.

Rehabilitation of severe dentofacial deformity after early radiotherapy of retinoblastoma: a case report.

BACKGROUND: Retinoblastoma is an intraocular cancer of infancy and childhood, which has been treated with radiation therapy and chemotherapy. Radiation on growing patients can cause deterioration in maxillofacial growth and development that leads to severe skeletal discrepancies between the maxilla and mandible, and dental problems such as crossbite, openbite, and hypodontia. CASE PRESENTATION: We present the case of a 19-year-old Korean man with chewing disability and dentofacial deformities. He had undergone enucleation of the right eye and radiation therapy of the left eye due to retinoblastoma 100 days after birth. Subsequently, he received cancer therapy for the secondary nasopharyngeal cancer at the age of 11 years. He was diagnosed with severe skeletal deformity including sagittal, transverse, and vertical growth deficiency of the maxilla and midface, and with class III malocclusion, severe anterior and posterior crossbite, posterior openbite, multiple missing upper incisors, right premolars, and second molars, and impaction of the lower right second molars. To restore impaired functions and esthetics of the jaw and dentition, the orthodontic treatment combined with two jaw surgery was performed. At the end of surgical orthodontics, dental implants were placed for prosthetic treatment of missing teeth. Additional plastic surgery for zygoma elevation was done with calvarial bone graft followed by fat graft. Facial esthetics and occlusal functions of patient were favorably enhanced with the improvement of skeletal discrepancy and the rehabilitation of maxillary dentition by prosthetic work. At the 2-year follow-up, the skeletal and dental relationships and implant prosthetics were well maintained. CONCLUSION: In an adult patient with dentofacial deformities caused by early cancer therapy in the head and neck area, interdisciplinary interventions including additional plastic surgery of zygoma depression and prosthetic work of missing teeth as well as surgical-orthodontic treatment could establish favorable facial esthetics and oral rehabilitation.

Comparison of treatment effects between two types of facemasks in early Class III patients.

OBJECTIVE: To compare the short-term treatment effects between two types of facemasks in skeletal Class III patients. MATERIALS AND METHODS: This retrospective study included 40 skeletal Class III subjects (mean age: 7.7 years) who had been treated with protraction facemasks with forehead straps (PFFS) or Petit type facemasks (PTF). Lateral cephalograms were analyzed at pretreatment (T1) and posttreatment (T2) with an average interval of 9 months. RESULTS: At T1, PFFS and PTF groups showed similar sagittal, vertical dentoskeletal patterns. From T1 to T2, both groups presented significant forward movement of the maxilla, posterior movement and clockwise rotation of the mandible (all p < .001), labioversion of the maxillary incisors, and linguoversion of the mandibular incisors. They showed increased overjet (p < .001). Although there were no significant differences in the number of changes in most dentoskeletal variables between the two groups, the PFFS group showed more anterior rotation of the palatal plane and backward rotation of the mandible compared to the PTF group, resulting in a significant decrease (-0.42 mm) in overbite (p < .05). CONCLUSIONS: Both PFFS and PTF showed no significant differences in most skeletal and dental changes, except for overbite. These findings might be helpful for clinicians in selecting the types of facemasks for growing Class III malocclusion patients.

Accuracy of a surface-based fusion method when integrating digital models and the cone beam computed tomography scans with metal artifacts.

The aim of this study was to evaluate the intra- and inter-observer reliability of maxillary digital dental model integration into cone-beam computed tomography (CBCT) scans to reconstruct three-dimensional (3D) skeletodental models for orthognathic patients. This retrospective study consisted of CBCT and digital maxillary dentition images of 20 Class III orthognathic patients. After two repeated fusions of digital cast images with reconstructed CBCT images by a digital engineer and an orthodontist respectively, the 3D coordinate values of the canines, first molars, and central incisors were evaluated. The intra- and inter-observer reliability of 3D positions of maxillary teeth were compared using intraclass correlation coefficients (ICCs). Intra-observer reliability of x-, y-, and z-coordinate values of maxillary teeth showed significant and excellent agreement in an engineer (0.946 ≤ ICC ≤ 1.000) and an orthodontist (0.876 ≤ ICC ≤ 1.000). The inter-observer reliability of the y- and z-coordinates of each tooth was significantly excellent or good, but that of the x-coordinates showed insignificantly poor to moderate agreement. This study showed that the integration of maxillary digital models into CBCT scans was clinically reliable. However, considering the low inter-observer reliability on the x-coordinates of dentition, clinical experience and repeated learning are needed for accurate application of digital skeletodental model in orthognathic patients.

Soft Tissue Changes After Clockwise Rotation of Maxillo-Mandibular Complex in Class III Patients: Three-Dimensional Stereophotogrammetric Evaluation.

OBJECTIVES: To evaluate the linear, angular, and volumetric changes of soft tissue after clockwise repositioning of the maxillo-mandibular complex in skeletal class III patients using three-dimensional (3D) stereophotogrammetry and to determine the correlation between changes in the skeletal and soft tissue variables. METHODS: This study included 18 skeletal class III patients who underwent two-jaw surgery; superior impaction and clockwise rotational movement of the maxilla with the rotation center at upper incisors, and setback of the mandible. Lateral cephalograms and 3D photographs taken before and 6 months after surgery were compared. RESULTS: After maxillary impaction of anteriorly 1.7 mm and posteriorly 3.1 mm, and mandibular setback of 8.7 mm, the volume of lower lip and chin region decreased significantly by 33.6 cm3 (13% net change, P < 0.001), while paranasal and upper lip region volume increased by 3.2 cm3 (2%) and 7.2 cm3 (4%), respectively. CONCLUSION: The clockwise rotation of maxillo-mandibular complex in class III patients significantly reduced lower lip and chin volume with minimal increase in paranasal and upper lip volumes. 3D stereophotogrammetry can provide quantitative evaluation of facial soft tissue volumetric changes.

Accuracy of intraoral scan images in full arch with orthodontic brackets: a retrospective in vivo study.

OBJECTIVES: The purpose of this retrospective study was to evaluate the accuracy of intraoral scan (IOS) images in the maxillary and mandibular arches with orthodontic brackets. MATERIAL AND METHODS: From digital impressions of 140 patients who underwent orthodontic treatment, consecutive IOS images were selected based on standardized inclusion criteria: Two pre-orthodontic IOS images (IOS1 and IOS2) of permanent dentition with fully erupted second molars and IOS images obtained immediately after orthodontic bracket bonding (IOSb). Superimpositions were performed to evaluate the reproducibility of repeated IOS images. Accuracy of IOSb images was analyzed by comparing the average surface errors between IOS1c and IOS2c images, which were IOS images cut based on the same region of the interest as between IOS1 and IOSb images. RESULTS: A total of 84 IOS images was analyzed. The average surface errors between IOS1 and IOS2 images were 57 ± 8 µm and 59 ± 14 µm in the maxillary and mandibular arch, respectively, and their reliability was almost perfect. The average errors between IOSb and IOS1c images exhibited an increase, which measured 97 ± 28 µm in the maxillary arch and 95 ± 29 µm in the mandibular arch. These surface deviations between IOSb and IOS1c images were significantly larger in each region as well as entire dentition (P < 0.001) compared to those between IOS1c and IOS2c images. CONCLUSIONS: The average surface errors of the scans with brackets showed increased values compared with those without brackets. This suggests that orthodontic brackets could affect the trueness of intraoral scan images. CLINICAL RELEVANCE: It is necessary for clinicians to consider the effect of brackets on digital impression when using IOS images in orthodontic patients.

Changes in maximum lip-closing force after extraction and nonextraction orthodontic treatments.

Objective: The aims of the present study were to evaluate the changes in the maximum lip-closing force (MLF) after orthodontic treatment with or without premolar extractions and verify the correlation of these changes with dentoskeletal changes. Methods: In total, 17 women who underwent nonextraction orthodontic treatment and 15 women who underwent orthodontic treatment with extraction of all four first premolars were included in this retrospective study. For all patients, lateral cephalograms and dental models were measured before (T0) and after (T1) treatment. In addition, MLF was measured at both time points using the Lip De Cum LDC-110R® device. Statistical analyses were performed to evaluate changes in clinical variables and MLF and their correlations. Results: Both groups showed similar skeletal patterns, although the extraction group showed greater proclination of the maxillary and mandibular incisors and lip protrusion compared to the nonextraction group at T0. MLF at T0 was comparable between the two groups. The reduction in the arch width and depth and incisor retroclination from T0 to T1 were more pronounced in the extraction group than in the nonextraction group. MLF in the extraction group significantly increased during the treatment period, and this increase was significantly greater than that in the nonextraction group. The increase in MLF was found to be correlated with the increase in the interincisal angle and decrease in the intermolar width, arch depth, and incisor-mandibular plane angle. Conclusions: This study suggests that MLF increases to a greater extent during extraction orthodontic treatment than during nonextraction orthodontic treatment.

Septal Integration Graft, a Modified Direct Type of Septal Extension Graft for the Treatment of Unilateral Cleft Lip Nose Deformity: An Anthropometric Analysis.

BACKGROUND: The purpose of this study was to evaluate the cosmetic outcomes and stability of septal integration grafts (SIGs), a modified direct type of septal extension graft, in patients with cleft lip nose deformity. METHODS: Seventy-three patients underwent SIGs between January 2002 and July 2017. The exclusion criteria were patients who lacked clinical photographs preoperatively or postoperatively. We reviewed data regarding the patient demographics, combined procedures, and complications as well as preoperative and postoperative clinical photography. Eleven measurement items were evaluated from basal and right lateral views with photogrammetry and 3-dimensional anthropometry using standardized clinical photographic techniques. RESULTS: Sixty-one patients were analyzed in this study. Twelve patients were excluded owing to a lack of postoperative photographs. The mean ± SD follow-up period was 26.70 ± 29.43 months (range, 6-134 months). Compared with the preoperative value, the nasal tip projection index, height of nose index, and nostril axis inclination significantly improved. The columellar length (Rt-Lt) index significantly decreased, which implied improved columellar deviation. Complications included hematoma (n = 1), wound dehiscence (n = 1), tearing of septal mucosa (n = 3), and silicone implant deviation (n = 2). CONCLUSIONS: We used SIGs to correct nasal deformity in patients with cleft lip nose deformity. The SIG can minimize the amount of the graft used for septal extension and can effectively correct nasal tip and columella deformities.

Hyaluronic acid-cross-linked filler stimulates collagen type 1 and elastic fiber synthesis in skin through the TGF-ß/Smad signaling pathway in a nude mouse model.

Compared to pure hyaluronic acid filler, cross-linked hyaluronic acid (HAc) exhibits superior biocompatibility and longevity as a dermal filler. We previously developed composite HAc-hydroxyapatite (HAp) fillers. Herein, we systematically compared the protein-level increase and gene expression between HAc-micro-HAp and HAc-nano-HAp in mice and determined the mechanisms underlying the biological responses to HAc and HAp. Five-week-old female BALB/c-nude mice were classified into five groups: normal skin, Radiesse, Restylane, HAc-nano-HAp, and HAc-micro-HAp. Fillers (200 µl) were injected to evenly fill the back of mice. Skin biopsies were performed to investigate collagen and elastic fiber synthesis after filler injections. Western blot analysis, real-time polymerase chain reaction analysis, and immunohistochemistry were performed to investigate protein and gene expression changes. Organ (liver, lung, spleen, and kidney) toxicity of HAc-nano-HAp was determined by hematoxylin and eosin staining after 12 weeks. Protein and gene expression analyses indicated that, compared with pure fillers, HAc-nano-HAp and HAc-micro-HAp hydrogels preferentially promoted collagen and elastic fiber formation through the TGF-ß pathway. The composite fillers also exhibited no evidence of organ toxicity. HAc-HAp filler might play an important role in collagen and elastic fiber regeneration. HAc filler stimulates collagen type 1 and elastic fiber synthesis through the TGF-ß/Smad pathway. The role of HAc-HAp composite fillers in photoaging in animal models and their effects on skin, including elasticity and tensile strength, should be investigated.

Factors Related to Relapse After Mandibular Setback Surgery With Minimal Presurgical Orthodontics.

PURPOSE: The aims of this study were to compare the presurgical conditions, surgical changes, and postsurgical changes in patients with skeletal Class III malocclusion with different degrees of horizontal relapse after mandibular setback surgery (MS) with minimal presurgical orthodontics (MPO) and to identify the factors contributing to this relapse. MATERIALS AND METHODS: For this retrospective study, 33 consecutive patients who underwent MS-MPO were selected. Lateral cephalograms were taken preoperatively (T0), 1 month after surgery (T1), and at orthodontic debonding (T2). Patients were divided into low relapse (LR; n = 18; relapse, <1 mm) and high relapse (HR; n = 15; relapse, >2 mm) groups based on the cephalometric distance of mandibular horizontal relapse. Paired t test, independent t test, and Pearson correlation analysis were used to evaluate surgical (T0 to T1) and postsurgical (T1 to T2) changes in the skeletodental variables and to explore the relation between surgical changes and horizontal relapse. RESULTS: Compared with the LR group, the HR group exhibited more upward movement with counterclockwise rotation of the mandible from T1 to T2. The HR group presented at T0 with a more prognathic mandible, greater vertical facial height, and a positive overbite. In addition, the HR group presented more posterior movement with clockwise rotation of the mandible, increased overjet, and decreased overbite from T0 to T1. Horizontal relapse of the mandible was positively correlated with the amount of setback and clockwise rotation of the mandible and the change in overjet and was negatively correlated with the change in overbite. CONCLUSIONS: Mandibular instability was related to the extent of setback and clockwise rotation of the mandible, decreased overbite, and increased overjet during MS-MPO.

Model Analysis of Digital Models in Moderate to Severe Crowding: In Vivo Validation and Clinical Application.

OBJECTIVE: We investigated the suitability of intraoral-scan models for measuring tooth dimensions and the amount of crowding in patients with severe tooth crowding. MATERIALS AND METHODS: Fifty-eight patients who had undergone intraoral scans for diagnosis were included. Cast models were divided into two groups depending on the amount of crowding, as determined by initial caliper-based measurements (mild crowding [MC] group: <3.0 mm; severe crowding [SC] group: >4.5 mm). Twenty maxillary models and 20 mandibular models were used in this study. For the three types of models (i.e., IS digital model, C cast model, and CS digital model), the reproducibility and the precision of linear measurements were evaluated. RESULTS: We found that linear measurements made using digital calipers on a plaster model and on the relevant software were reproducible. There was no significant difference in most linear measurements between digital models and the C model. There were differences in the amount of crowding (p < .05), although these were not clinically significant. There was no relationship between the precision of crowding in the three types of models and the severity of crowding. CONCLUSIONS: Digital models can be used for measuring crowding in both mild and severe crowding cases. However, crowding measured by digital models tends to be lesser than that measured by cast models, and this should be considered during clinical application.

The accelerating effect of chitosan-silica hybrid dressing materials on the early phase of wound healing.

Commercialized dressing materials with or without silver have played a passive role in early-phase wound healing, protecting the skin defects from infections, absorbing exudate, and preventing dehydration. Chitosan (CTS)-based sponges have been developed in pure or hybrid forms for accelerating wound healing, but their wound-healing capabilities have not been extensively compared with widely used commercial dressing materials, providing limited information in a practical aspect. In this study, we have developed CTS-silica (CTS-Si) hybrid sponges with water absorption, flexibility, and mechanical behavior similar to those of CTS sponges. In vitro and in vivo tests were performed to compare the CTS-Si sponges with three commercial dressing materials [gauze, polyurethane (PU), and silver-containing hydrofiber (HF-Ag)] in addition to CTS sponges. Both in vitro and in vivo tests showed that CTS-Si sponges promoted fibroblast proliferation, leading to accelerated collagen synthesis, whereas the CTS sponges did not exhibit significant differences in fibroblast proliferation and collagen synthesis from gauze, PU, and HF-Ag sponges. In case of CTS-Si, the inflammatory cells were actively recruited to the wound by the influence of the released silicon ions from CTS-Si sponges, which, in return, led to an enhanced secretion of growth factors, particularly TGF-ß during the early stage. The higher level of TGF-ß likely improved the proliferation of fibroblasts, and as a result, collagen synthesis by fibroblasts became remarkably productive, thereby increasing collagen density at the wound site. Therefore, the CTS-Si hybrid sponges have considerable potential as a wound-dressing material for accelerating wound healing. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1828-1839, 2017.

Long-lasting and bioactive hyaluronic acid-hydroxyapatite composite hydrogels for injectable dermal fillers: Physical properties and in vivo durability.

Hyaluronic acid (HAc)-hydroxyapatite (HAp) composite hydrogels were developed to improve the biostability and bioactivity of HAc for dermal filler applications. Two kinds of HAc-HAp composite fillers were generated: HAcmicroHAp and HAc-nanoHAp composites. HAc-microHAp was fabricated by mixing HAp microspheres with HAc hydrogels, and HAc-nanoHAp was made by in situ precipitation of nano-sized HAp particles in HAc hydrogels. Emphasis was placed on the effect of HAp on the durability and bioactivity of the fillers. Compared with the pure HAc filler, all of the HAc-HAp composite fillers exhibited significant improvements in volumetric maintenance based on in vivo tests owing to their reduced water content and higher degree of biointegration between the filler and surrounding tissues. HAc-HAp composite fillers also showed noticeable enhancement in dermis recovery, promoting collagen and elastic fiber formation. Based on their long-lasting durability and bioactivity, HAc-HAp composite fillers have great potential for soft tissue augmentation with multifunctionality.

Restoration of a vertical alveolar bone defect by orthodontic relocation of a mesially impacted mandibular first molar.

An impacted mandibular first molar tends to cause serious bone defects of the adjacent teeth. When choosing between the 2 typical treatment options-extraction or orthodontic relocation of the impacted tooth-the decision should be based on assessment of the prognosis. A 22-year-old man with severe mesioangulation and impaction of the mandibular first molar and a related vertical bone defect on the distal side of the second premolar was treated with extraction of the second molar and orthodontic relocation of the first molar with a retromolar miniscrew. Comprehensive orthodontic treatment involving premolar extraction was conducted. Strategic extraction of the molar and adequate orthodontic movement helped to restore the bone structure on the affected side. This case report suggests the effectiveness of restoration of bone defects by using viable periodontal tissues around the impacted tooth for the longevity of the periodontium.

Mandibular posterior anatomic limit for molar distalization.

INTRODUCTION: The purpose of this study was to investigate the mandibular posterior anatomic limit for molar distalization. METHODS: Three-dimensional computed tomography scans were obtained on 34 adults with a skeletal Class I normodivergent facial profile and a normal occlusion. Posterior available space was measured at the crown and root levels along the posterior occlusal line connecting the buccal cusps of the first and second molars on the axial slices. It was also measured at the occlusal level on the lateral cephalograms derived from the computed tomography scans. The measurements on the cephalograms were used to predict the actual posterior available space determined by computed tomography and to determine the presence of root contact with the inner lingual cortex by linear regression and discriminant analyses, respectively. RESULTS: The posterior available space was significantly smaller at the root level than at the crown level. Root contact was observed in 35.3% of the 68 roots. The posterior available space measured on the lateral cephalograms resulted in a regression equation with a coefficient of determination of 0.261 to predict actual available space and correctly identified root contact in 66.2% of cases with a threshold value of 3.9 mm. CONCLUSIONS: The posterior anatomic limit appeared to be the lingual cortex of the mandibular body. Computed tomography scans are recommended for patients who require significant mandibular molar distalization.

Combined use of miniscrews and continuous arch for intrusive root movement of incisors in Class II division 2 with gummy smile.

Adequate intrusion and torque control of the retroclined maxillary incisors are critical for the treatment of Class II division 2 (div2) malocclusion. In addition, anterior retraction via lingual root movement can be challenging. This case report demonstrates a combined use of miniscrews and continuous arch with additional torque for intrusion, retraction, and torque control of maxillary incisors in the Class II div2 with gummy smile. A 20-year-old woman presented with multiple issues, including impacted canine, lip protrusion, prolonged retained mandibular primary molar, and two missing maxillary premolars. In order to improve her facial profile and eliminate the need for prosthetic work, the mandibular primary molar and contralateral premolar were extracted. Two miniscrews were placed at the maxillary buccal alveolar bone to apply the posterosuperior force for retraction of anterior teeth, with additional labial crown torque on the arch wire. The results were the intrusion (4 mm) and lingual root movement (17°) of the maxillary incisors without anchorage loss of maxillary molars, flattening of the Curve of Spee, and Class I molar relation that were maintained after 50 months of retention period. The combined use of miniscrews and continuous arch could be a reliable and effective treatment modality for torque control and intrusion of retroclined maxillary incisors in the Class II div2 patient.

Timely relocation of subapically impacted maxillary canines and replacement of an ankylosed mandibular molar are the keys to eruption disturbances in a prepubertal patient.

Eruption disturbances such as impaction and ankylosis complicate orthodontic treatment because soft-tissue and hard-tissue considerations must be taken into account. Treatment is further complicated when such eruption disturbances occur in a growing patient. Extraction of impacted or ankylosed teeth can be an option that carries the weight of additional prostheses and bony defects, whereas exposure or luxation followed by orthodontic traction can preserve the patient's teeth and bony structure with improved esthetics. Therefore, an accurate diagnosis is needed in establishing an efficient and effective force system to achieve the desired tooth movements with few unwanted sequelae. This case report describes the process of differential diagnosis with the aid of 3-dimensional imaging in constructing a force-driven system, using the centers of resistance as reference points, to successfully bring a pair of impacted maxillary canines into alignment and protract a mandibular molar to achieve an acceptable occlusion in an adolescent girl.