1
|
Qiao Q, Zhang L, Xie X, Bai Y, Su L. Using a structured light scanner to evaluate 3-dimensional soft-tissue changes after extracting 4 premolars in young adult female patients. Am J Orthod Dentofacial Orthop 2024; 165:80-92.e4. [PMID: 37715754 DOI: 10.1016/j.ajodo.2023.07.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 07/01/2023] [Accepted: 07/01/2023] [Indexed: 09/18/2023]
Abstract
INTRODUCTION Facial esthetics have always received much attention in orthodontic treatment, especially in young adult female patients. Three-dimensional (3D) soft-tissue changes after orthodontic extraction have not been fully explained. This study evaluated the 3D morphologic changes after orthodontic extraction in young female patients using a structured light scanner. METHODS Forty-five adult female patients aged 20-25 years were enrolled in our study. The treatment group consisted of patients who received orthodontic treatment with 4 premolar extractions, and the control group was composed of young female volunteers who had not undergone any orthodontic treatment. To monitor the soft-tissue changes, 9 morphologic regions and 12 landmarks were identified for the 3D deviation analyses. The spatial deviations of landmarks and regions in the x, y, and z directions were constructed for quantitative analysis. Color map images were constructed to visualize soft-tissue displacement as a qualitative evaluation. The paired sample test was used to compare differences at the beginning of the experiment (T0) and after 24 months (T1) in both groups. An independent t test with Bonferroni correction was performed to compare differences between the treatment and control groups. A linear regression test was performed between incisor retraction and changes in the perioral tissues. RESULTS Subtracting the effect of aging from the lip changes in the control group, the treatment group showed a statistically significant difference in the displacement of labrale superius (-1.37 mm), labrale inferius (-1.89 mm), the upper lip region (-0.98 mm), and the lower lip region (-1.36 mm) along the z-axis. No significant differences were found between the treatment and control groups in the temporal, parotideomasseteric, and buccal regions. Pearson correlation tests indicated a positive correlation between incisor tip retraction and changes in soft tissues (two-dimensional cephalometric analysis, 3D landmark measurements, and 3D regional measurements). The correlation coefficient ranged between 0.45 and 0.55. CONCLUSIONS Three-dimensional soft-tissue changes were mainly concentrated in the upper and lower lip regions in adult female patients after the 4 premolars were extracted. For female patients aged 20-25 years with 4 extracted premolars, soft-tissue changes in the temporal, parotideomasseteric, and buccal regions were not clinically significant.
Collapse
Affiliation(s)
- Qingchen Qiao
- School of Stomatology, Capital Medical University, Beijing, China
| | - Li Zhang
- Department of Orthodontics, School of Stomatology, Capital Medical University, Beijing, China
| | - Xianju Xie
- Department of Orthodontics, School of Stomatology, Capital Medical University, Beijing, China
| | - Yuxing Bai
- Department of Orthodontics, School of Stomatology, Capital Medical University, Beijing, China.
| | - Li Su
- Department of Orthodontics, School of Stomatology, Capital Medical University, Beijing, China.
| |
Collapse
|
2
|
Kim HJ, Noh HK, Park HS. Differences in facial soft tissue deviations in Class III patients with different types of mandibular asymmetry: A cone-beam computed tomography study. Korean J Orthod 2023; 53:402-419. [PMID: 37989577 PMCID: PMC10663576 DOI: 10.4041/kjod23.106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 08/25/2023] [Accepted: 09/04/2023] [Indexed: 11/23/2023] Open
Abstract
Objective : This study assessed the differences in soft tissue deviations of the nose, lips, and chin between different mandibular asymmetry types in Class III patients. Methods : Cone-beam computed tomography data from 90 Class III patients with moderate-to-severe facial asymmetry were investigated. The sample was divided into three groups based on the extent of mandibular rolling, yawing, and translation. Soft tissue landmarks on the nose, lips, and chin were investigated vertically, transversely, and anteroposteriorly. A paired t test was performed to compare variables between the deviated (Dv) and nondeviated (NDv) sides, and one-way analysis of variance with Tukey's post-hoc test was performed for intergroup comparisons. Pearson's correlation coefficient was calculated to assess the relationship between the soft and hard tissue deviations. Results : The roll-dominant group showed significantly greater differences in the vertical positions of the soft tissue landmarks between the Dv and NDv than other groups (P < 0.05), whereas the yaw-dominant group exhibited larger differences in the transverse and anteroposterior directions (P < 0.05). Moreover, transverse lip cant was correlated with the menton (Me) deviation and mandibular rolling in the roll-dominant group (P < 0.001); the angulation of the nasal bridge or philtrum was correlated with the Me deviation and mandibular yawing in the yaw-dominant group (P < 0.01). Conclusions : The three-dimensional deviations of facial soft tissue differed based on the mandibular asymmetry types in Class III patients with similar amounts of Me deviation. A precise understanding of soft tissue deviation in each asymmetry type would help achieve satisfactory facial esthetics.
Collapse
Affiliation(s)
- Ho-Jin Kim
- Department of Orthodontics, School of Dentistry, Kyungpook National University, Daegu, Korea
| | - Hyung-Kyu Noh
- Department of Orthodontics, School of Dentistry, Kyungpook National University, Daegu, Korea
| | - Hyo-Sang Park
- Department of Orthodontics, School of Dentistry, Kyungpook National University, Daegu, Korea
| |
Collapse
|
3
|
Nam JH, Choi Y, Lee KJ, Lee JH, Kim KH, Chung CJ. Differences in the 3-dimensional aging changes of the lips among female adults with skeletal Class I, II, and III malocclusion. Am J Orthod Dentofacial Orthop 2023; 164:516-529. [PMID: 37074244 DOI: 10.1016/j.ajodo.2023.02.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 02/01/2023] [Accepted: 02/01/2023] [Indexed: 04/20/2023]
Abstract
INTRODUCTION The objective of this study was to evaluate and compare the 3-dimensional (3D) aging changes of the lips among adult skeletal Class I, II, and III malocclusion. METHODS Female adult orthodontic patients aged 20-50 years with pretreatment cone-beam computed tomography scans were retrospectively classified according to age (20s [20-29 years], 30s [30-39 years], and 40s [40-49 years]) and then subclassified by malocclusion into skeletal Class I, II, and III relationship (9 groups; n = 30 per group). Positional differences in midsagittal and parasagittal soft-tissue landmarks and 3D morphologic aging changes of the lips were evaluated using cone-beam computed tomography scans. RESULTS Labiale superius and cheilion for patients in their 40s indicated a significant downward and backward position compared with those in their 20s, regardless of skeletal classifications (P <0.05). Accordingly, the upper lip height decreased, and the mouth width increased significantly (P <0.05). For Class III malocclusion, the upper lip vermilion angle was greater for patients in their 40s than those in their 20s (P <0.05), whereas the lower lip vermilion angle was only lower for patients with Class II malocclusion (P <0.05). CONCLUSIONS Middle-aged adult females (40-49 years) had a lower upper lip height and greater mouth width than those in their 20s, regardless of skeletal malocclusion. However, prominent morphologic aging changes of the lips were noted on the upper lip for skeletal Class III malocclusion and the lower lip for skeletal Class II malocclusion, implying that the underlying skeletal features (or malocclusion) may influence 3D aging changes of the lips.
Collapse
Affiliation(s)
- Ji-Hye Nam
- Department of Orthodontics, The Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, South Korea
| | - Youngjun Choi
- Department of Oral and Maxillofacial Surgery, Dental Center, Chung-Ang University Hospital, Seoul, South Korea
| | - Kee-Joon Lee
- Department of Orthodontics, The Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, South Korea
| | - Ji-Hyun Lee
- Department of Orthodontics, The Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, South Korea; Department Orthodontics, Gangnam Severance Hospital, The Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, South Korea
| | - Kyung-Ho Kim
- Department of Orthodontics, The Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, South Korea; Department Orthodontics, Gangnam Severance Hospital, The Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, South Korea
| | - Chooryung J Chung
- Department of Orthodontics, The Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, South Korea; Department Orthodontics, Gangnam Severance Hospital, The Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, South Korea.
| |
Collapse
|
4
|
Zhou Q, Gao J, Guo D, Zhang H, Zhang X, Qin W, Jin Z. Three dimensional quantitative study of soft tissue changes in nasolabial folds after orthodontic treatment in female adults. BMC Oral Health 2023; 23:31. [PMID: 36658527 PMCID: PMC9854211 DOI: 10.1186/s12903-023-02733-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 01/11/2023] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND With the popularity of medical aesthetic programs, some female adults who will or are undergoing orthodontic treatment often wonder whether orthodontic treatment has adverse effects on the nasolabial folds (NLFs). The aims of the study were to investigate any potential changes in the NLFs and associated peripheral soft tissues after orthodontic treatment of female adults. METHODS This study compared changes in the NLFs and peripheral soft tissues in female adults undergoing orthodontic treatment using the 3dMD Face system (3dMD, Atlanta, Ga). A total of 52 adult female patient cases (24 teeth extraction, 28 non-teeth extraction) were included to evaluate the effects of different orthodontic treatment regimens on the NLFs and peripheral soft tissues. RESULTS In the NLFs area, the landmarks of the extraction group were all significantly negatively changed (P < 0.001; the NLF2s average value was - 0.72 mm), and the upper and middle parts of the landmarks were negatively changed in the non-extraction group (P < 0.05; the NLF2s average value was - 0.22 mm). Compared to the non-extraction group, the negative changes in the extraction group were more pronounced (P < 0.005). In the lip region, all landmarks in the extraction group were negative changes (P < 0.05; upper lip (ULP) = - 0.93 mm, lower lip (LLP) = - 1.46 mm), and most landmarks in the non-extraction group were positive changes (P < 0.01; ULP = 0.55 mm). In the cheek area, the left and right buccal of the extraction and non-extraction groups were all negatively changed (P < 0.05), and there was no significant difference between the two groups. CONCLUSION After orthodontic treatment, the NLFs showed negative changes, which were more obvious in the extraction group. The lip soft tissue had a negative change in the extraction group and a positive change in the non-extraction group, indicating that orthodontic treatment affected the soft tissue around the nasolabial sulcus, and that tooth extraction would lead to more negative changes.
Collapse
Affiliation(s)
- Qin Zhou
- grid.43169.390000 0001 0599 1243Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi’an Jiaotong University, No. 98 XiWu Road, Xi’an, 710004 Shaanxi China ,grid.43169.390000 0001 0599 1243Department of Orthodontics, College of Stomatology, Xi’an Jiaotong University, No. 98 XiWu Road, Xi’an, 710004 Shaanxi China ,grid.233520.50000 0004 1761 4404State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, The Fourth Military Medical University, No. 169 Changle West Road, Xi’an, 710032 Shaanxi China
| | - Jie Gao
- grid.233520.50000 0004 1761 4404State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, The Fourth Military Medical University, No. 169 Changle West Road, Xi’an, 710032 Shaanxi China
| | - Donghui Guo
- grid.233520.50000 0004 1761 4404State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, The Fourth Military Medical University, No. 169 Changle West Road, Xi’an, 710032 Shaanxi China
| | - Haolin Zhang
- grid.233520.50000 0004 1761 4404State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, The Fourth Military Medical University, No. 169 Changle West Road, Xi’an, 710032 Shaanxi China ,Department of Stomatology, The PLA Hong Kong Garrison Hospital, Hong Kong, 999077 China
| | - Xu Zhang
- grid.233520.50000 0004 1761 4404State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, The Fourth Military Medical University, No. 169 Changle West Road, Xi’an, 710032 Shaanxi China
| | - Wen Qin
- grid.233520.50000 0004 1761 4404State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, The Fourth Military Medical University, No. 169 Changle West Road, Xi’an, 710032 Shaanxi China
| | - Zuolin Jin
- grid.233520.50000 0004 1761 4404State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, Department of Orthodontics, School of Stomatology, The Fourth Military Medical University, No. 169 Changle West Road, Xi’an, 710032 Shaanxi China
| |
Collapse
|
5
|
Park YS, Choi JH, Kim Y, Choi SH, Lee JH, Kim KH, Chung CJ. Deep Learning-Based Prediction of the 3D Postorthodontic Facial Changes. J Dent Res 2022; 101:1372-1379. [PMID: 35774018 DOI: 10.1177/00220345221106676] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
With the increase of the adult orthodontic population, there is a need for an accurate and evidence-based prediction of the posttreatment face in 3 dimensions (3D). The objectives of this study are 1) to develop a 3D postorthodontic face prediction method based on a deep learning network using the patient-specific factors and orthodontic treatment conditions and 2) to validate the accuracy and clinical usability of the proposed method. Paired sets (n = 268) of pretreatment (T1) and posttreatment (T2) cone-beam computed tomography (CBCT) of adult patients were trained with a conditional generative adversarial network to generate 3D posttreatment facial data based on the patient's gender, age, and the changes of upper (ΔU1) and lower incisor position (ΔL1) as input. The accuracy was calculated with prediction error and mean absolute distances between real T2 (T2) and predicted T2 (PT2) near 6 perioral landmark regions, as well as percentage of prediction error less than 2 mm using test sets (n = 44). For qualitative evaluation, an online survey was conducted with experienced orthodontists as panels (n = 56). Overall, PT2 indicated similar 3D changes to the T2 face, with the most apparent changes simulated in the perioral regions. The mean prediction error was 1.2 ± 1.01 mm with 80.8% accuracy. More than 50% of the experienced orthodontists were unable to distinguish between real and predicted images. In this study, we proposed a valid 3D postorthodontic face prediction method by applying a deep learning algorithm trained with CBCT data sets.
Collapse
Affiliation(s)
- Y S Park
- Department of Orthodontics, The Institute of Craniofacial Deformity, Yonsei University College of Dentistry, Seoul, Korea
| | - J H Choi
- Smile Future Orthodontics, Seoul, Korea.,Department of Orthodontics, School of Dentistry, Seoul National University, Seoul, Korea
| | - Y Kim
- Imagoworks Inc., Seoul, Korea
| | - S H Choi
- Department of Orthodontics, The Institute of Craniofacial Deformity, Yonsei University College of Dentistry, Seoul, Korea
| | - J H Lee
- Department of Orthodontics, The Institute of Craniofacial Deformity, Yonsei University College of Dentistry, Seoul, Korea.,Department of Orthodontics, Gangnam Severance Hospital Yonsei University, Seoul, Korea
| | - K H Kim
- Department of Orthodontics, The Institute of Craniofacial Deformity, Yonsei University College of Dentistry, Seoul, Korea.,Department of Orthodontics, Gangnam Severance Hospital Yonsei University, Seoul, Korea
| | - C J Chung
- Department of Orthodontics, The Institute of Craniofacial Deformity, Yonsei University College of Dentistry, Seoul, Korea.,Department of Orthodontics, Gangnam Severance Hospital Yonsei University, Seoul, Korea
| |
Collapse
|
6
|
Morphologic changes of the incisive canal and its proximity to maxillary incisor roots after anterior tooth movement. Am J Orthod Dentofacial Orthop 2021; 161:396-403.e1. [PMID: 34654602 DOI: 10.1016/j.ajodo.2020.08.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 08/01/2020] [Accepted: 08/01/2020] [Indexed: 01/25/2023]
Abstract
INTRODUCTION The objectives were to evaluate the morphologic changes of the incisive canal (IC) and the influence of IC proximity to apical root resorption of maxillary central incisors after anterior tooth movement. METHODS Pretreatment and posttreatment cone-beam computed tomography images of adults (aged 18-47 years) were retrospectively evaluated. Subjects were divided into control group with minimal incisor movement (n = 32; maxillary incisor tip movement <2 mm) and maximum retraction group (n = 35; maxillary incisor tip movement >4 mm). The shape, direction, morphologic changes of the IC, the proximity of the central incisor root to IC, and the amount of apical root resorption associated with the proximity after orthodontic treatment were compared. RESULTS Changes in the shape of the IC were not observed in both control and retraction groups. However, 11.4% (4 of 35 subjects) in the retraction group indicated changes in the direction of the IC from slanted-straight to slanted-curved type after the direction of anterior retraction. The thickness of the cortical bone surrounding the IC and the distance between the incisor root and IC significantly decreased after orthodontic treatment in both groups (P <0.05). However, these changes were significantly greater in the retraction group than in control (P <0.0001). Contact or invasion of the incisor root to the IC was more prominent in the retraction group (42.8%-54.3%) than the control (10.9%-12.5%) (P <0.0001). The amount of root resorption indicated a tendency to increase in the order of separation, approximation, contact, and invasion in relation to IC. CONCLUSIONS Although remodeling of IC was evident in some patients, contact or invasion of the maxillary central incisor roots to IC was fairly high after maximum anterior retraction.
Collapse
|
7
|
Chung CJ, Nguyen T, Lee JH, Kim KH. Incisive canal remodelling following maximum anterior retraction reduces apical root resorption. Orthod Craniofac Res 2020; 24 Suppl 1:59-65. [PMID: 33369873 DOI: 10.1111/ocr.12464] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/08/2020] [Accepted: 12/15/2020] [Indexed: 02/03/2023]
Abstract
INTRODUCTION The objectives were to visualize the incisive canal (IC) remodelling following maximum incisor retraction and to evaluate its impact on canal-invasion-associated apical root resorption. METHODS Pre- and post-treatment CBCT images of 34 adult orthodontic patients (age 18-47 years) with a large amount of maxillary incisor retraction (>4 mm) using temporary anchorage devices (TADs) were retrospectively evaluated. Maxillary regional superimpositions and 3D models of the IC along with central incisors were used to measure the changes in IC dimension, IC invasion by the roots and IC remodelling. In addition, the association of the amount of apical root resorption with the root-IC relationship and IC remodelling were evaluated. RESULTS IC invasion by the incisor roots following maximum retraction was seen in 53% (18 out of 34) of the cases. IC with larger volume and area showed more invasions compared with those with smaller volume and area (P < .01). The amount of root resorption was significantly higher with IC invasion than without invasion (2.39 mm vs 0.82 mm, P < .0001). IC remodelling following maximum retraction was seen in 24% of the subjects. IC remodelling group demonstrated less apical root resorption than the non-remodelling group (0.98 mm vs 3.27 mm, P < .0001). CONCLUSION IC with larger volume and surface area before treatment were more likely to show canal invasion by the incisor roots after maximum retraction. IC invasion resulted in apical root resorption. However, approximately one-fourth of cases showed remodelling of the IC, which reduced the amount of root resorption.
Collapse
Affiliation(s)
- Chooryung J Chung
- Department of Orthodontics, Gangnam Severance Hospital, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, Seoul, Korea
| | - Tung Nguyen
- Department of Orthodontics, University of North Carolina at Chapel Hill School of Dentistry, Chapel Hill, NC, USA
| | - Jee-Hyun Lee
- Department of Orthodontics, Gangnam Severance Hospital, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, Seoul, Korea
| | - Kyung-Ho Kim
- Department of Orthodontics, Gangnam Severance Hospital, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, Seoul, Korea
| |
Collapse
|
8
|
Hou J, Meng X. Orthodontic treatment of an adult Class II division 1 malocclusion with nonextraction assisted by lip myofunctional training: A case report. Clin Case Rep 2020; 8:1171-1179. [PMID: 32695351 PMCID: PMC7364072 DOI: 10.1002/ccr3.2859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/06/2020] [Accepted: 03/20/2020] [Indexed: 11/10/2022] Open
Abstract
Consideration of facial soft tissue is critical in orthodontic diagnosis and treatment planning to achieve improvement in facial esthetics as well as dental occlusion. As is illustrated by success in orthodontic treatment of an adult Class II division 1 malocclusion with nonextraction and assisted by lip myofunctional training.
Collapse
Affiliation(s)
- Jianhua Hou
- Department of OrthodonticsHospital of StomatologyJilin UniversityChangchunChina
| | - Xiuping Meng
- Department of EndodonticsHospital of StomatologyJilin UniversityChangchunChina
| |
Collapse
|
9
|
Differential alveolar bone modeling after orthodontic retraction. J Am Dent Assoc 2019; 150:313-320. [PMID: 30922461 DOI: 10.1016/j.adaj.2018.12.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 11/26/2018] [Accepted: 12/28/2018] [Indexed: 12/19/2022]
Abstract
BACKGROUND Distinct, irregular, and hard nodular protuberances similar to the morphologic features of exostoses can occasionally be noted on the labial surface of the alveolar bone after orthodontic retraction of anterior teeth in adults. These have long been believed to be exostoses developed in response to loading. However, specific characterization of this phenomenon has not been documented. CASE DESCRIPTIONS Three cases of patients displaying multiple irregular labial bony protuberances after retraction of anterior teeth are reported. These protuberances appeared during retraction and became more prominent with additional retraction. Serial clinical photographs, lateral cephalograms, digital models, and cone-beam computed tomography scans were evaluated. On the basis of 3-dimensional superimpositions of digital models and cone-beam computed tomographic scans, the irregular protuberances appear to be the result of differential alveolar bone modeling, with more resorption of bone covering the tooth root than that of interdental bone, and not of true bone overgrowth or deposition (that is, exostoses). CONCLUSION AND PRACTICAL IMPLICATIONS Orthodontic patients often seek treatment to improve occlusion as well as esthetics. Although this study shows that these protuberances are the result of differential modeling, they may still be perceived by patients as "outgrowths," which may cause concerns related to esthetics or comfort. Clinicians should note that these protuberances are a possible outcome when large amounts of bodily retraction and root movement of anterior teeth are planned. Patients who experience psychosocial problems with this phenomenon may be candidates for alveoloplasty.
Collapse
|