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Zhang J, Liang Y, Chen R, Chen S, Lin J, Han B, Liu X. Inclination of mandibular incisors and symphysis in severe skeletal class III malocclusion. Head Face Med 2023; 19:16. [PMID: 37165461 PMCID: PMC10170675 DOI: 10.1186/s13005-023-00361-6] [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: 01/21/2023] [Accepted: 04/24/2023] [Indexed: 05/12/2023] Open
Abstract
OBJECTIVE The aim of this study was to systematically explore the inclination of the lower central incisor and symphysis in alveolar bone in severe skeletal class III patients. MATERIALS AND METHODS A total of 198 severe skeletal class III patients (ANB ≤ -4°) who underwent combined orthodontic and orthognathic treatment were divided into three groups based on the mandibular plane angle (MP-SN). Pretreatment lateral cephalograms were analysed and compared among the three groups. We also assessed cone-beam computed tomography (CBCT) images of 11 samples to investigate the reliability of the cephalometric analysis. RESULTS ANOVA showed no statistically significant differences in the angle between the long axis of the mandibular symphysis and the long axis of the lower central incisor (MIA) among the low-angle, normal-angle and high-angle groups (P > 0.05), while significant differences were found in the angle between the axis of the lower incisor and the mandibular plane (IMPA) among the three groups (P < 0.001). The mean IMPA decreased with increasing MP-SN in the 198 patients. The mean MIA in the low-angle and normal-angle groups was 3.70° and 3.52°, respectively, while the value (2.33°) was smaller in the high-angle group. Paired-samples t test showed no statistically significant differences between the cephalometric and CBCT measurements of the MP-SN, the angle between the mandibular plane and the Frankfort plane (FH-MP) and the MIA (P > 0.05). CONCLUSIONS In severe skeletal class III patients, the long axis of the lower central incisor was highly consistent with the long axis of the mandibular symphysis, which was more obvious in the high-angle subjects. The MIA reflects the physiological inclination of the lower central incisor better than the IMPA.
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Affiliation(s)
- Jieni Zhang
- Department of Orthodontics, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology & Research Center of Engineering and Technology for Computerized Dentistry Ministry of Health & NMPA Key Laboratory for Dental Materials, 22 Zhongguancun South Avenue, Haidian District, 100081, Beijing, China
| | - Yuqi Liang
- Department of Orthodontics, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology & Research Center of Engineering and Technology for Computerized Dentistry Ministry of Health & NMPA Key Laboratory for Dental Materials, 22 Zhongguancun South Avenue, Haidian District, 100081, Beijing, China
| | - Rui Chen
- Yuncheng Stomatological Hospital, Yuncheng, China
| | - Si Chen
- Department of Orthodontics, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology & Research Center of Engineering and Technology for Computerized Dentistry Ministry of Health & NMPA Key Laboratory for Dental Materials, 22 Zhongguancun South Avenue, Haidian District, 100081, Beijing, China
| | - Jiuxiang Lin
- Department of Orthodontics, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology & Research Center of Engineering and Technology for Computerized Dentistry Ministry of Health & NMPA Key Laboratory for Dental Materials, 22 Zhongguancun South Avenue, Haidian District, 100081, Beijing, China
| | - Bing Han
- Department of Orthodontics, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology & Research Center of Engineering and Technology for Computerized Dentistry Ministry of Health & NMPA Key Laboratory for Dental Materials, 22 Zhongguancun South Avenue, Haidian District, 100081, Beijing, China.
| | - Xiaomo Liu
- Department of Orthodontics, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology & Research Center of Engineering and Technology for Computerized Dentistry Ministry of Health & NMPA Key Laboratory for Dental Materials, 22 Zhongguancun South Avenue, Haidian District, 100081, Beijing, China.
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Wang XM, Meng WY, Wang WN, Huo YF, Xue H. Accuracy and eligibility of Bonwill⁃Hawley arch form established by CBCT image for dental crowding measurement: a comparative study with the conventional brass wire and caliper methods. Clin Oral Investig 2023:10.1007/s00784-023-05020-3. [PMID: 37071219 DOI: 10.1007/s00784-023-05020-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Accepted: 04/04/2023] [Indexed: 04/19/2023]
Abstract
OBJECTIVES The purpose of this study was to develop a novel Bonwill⁃Hawley method (Bonwill⁃Hawley arch form based on CBCT image) for the assessment of dental crowding, and to investigate and compare the accuracy and eligibility with the conventional brass wire and caliper methods under different crowding conditions. MATERIAL AND METHODS Sixty patients with the pair of plaster casts and CBCT data were collected. All the casts were marked and transformed into digital models using iTero scanner, and imported into OrthoCAD software to measure the required space. Using the conventional brass wire (M1) and caliper methods (M2), the available space and dental crowding were measured and calculated basing on digital models, respectively. Correspondingly, the axial planes in the level of dental arches were oriented and captured from the CBCT images to draw the Bonwill⁃Hawley arch forms (M3), which were used to measure and calculate the available space and dental crowding. For each method, intra and inter-examiner reliabilities were evaluated with intra-class correlation coefficients (ICCs). Wilcoxon test and Kruskal-Wallis test were performed for statistically analyzing the discrepancy among different groups. RESULTS Both intra- and inter-examiner reliability were generally excellent for all parameters obtained by the three methods, except for the dental crowding measured using M1(ICC: 0.473/0.261). The dental crowding measured using M2 were significantly increased in mild, moderate and severe-crowding groups compared with M1. However, no significant difference was detected between M1 and M3 in severe-crowding group (maxilla, p = 0.108 > 0.05; mandible, p = 0.074 > 0.05). With the deterioration of crowding condition, the discrepancy of dental crowding between M1 and M2, or M1 and M3 were significantly decreased (maxilla, M2-M1, mild VS serve, p = 0.003 < 0.05; maxilla, M3-M1, mild VS serve, p = 0.003 < 0.05; mandible, M2-M1, mild VS serve, p = 0.000 < 0.001; mandible, M3-M1, mild VS serve, p = 0.043 < 0.05). CONCLUSION Dental crowding measured using the novel Bonwill⁃Hawley method was relatively greater than the caliper method, but not exceeding the brass wire method, which wound gradually come close to the brass wire method with the deterioration of crowding condition. CLINICAL RELEVANCE The Bonwill⁃Hawley method basing on CBCT image proved to be a reliable and acceptable choice for orthodontists to analyze the dental crowding.
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Affiliation(s)
- Xiao-Ming Wang
- Key Laboratory of Dental Maxillofacial Reconstruction and Biological Intelligence Manufacturing (NO: 20JR10RA653 - ZDKF20210401), School of Stomatology, Lanzhou University, No. 199, Donggang West Road, Gansu Province, Lanzhou, 730000, People's Republic of China.
- Department of Orthodontics, School of Stomatology, Lanzhou University, No. 199, Donggang West Road, Gansu Province, Lanzhou, 730000, People's Republic of China.
| | - Wen-Yu Meng
- The First Hospital of Lanzhou University, Lanzhou, 730000, People's Republic of China
| | - Wei-Ning Wang
- Key Laboratory of Dental Maxillofacial Reconstruction and Biological Intelligence Manufacturing (NO: 20JR10RA653 - ZDKF20210401), School of Stomatology, Lanzhou University, No. 199, Donggang West Road, Gansu Province, Lanzhou, 730000, People's Republic of China
- Department of Orthodontics, School of Stomatology, Lanzhou University, No. 199, Donggang West Road, Gansu Province, Lanzhou, 730000, People's Republic of China
| | - Yi-Fei Huo
- Key Laboratory of Dental Maxillofacial Reconstruction and Biological Intelligence Manufacturing (NO: 20JR10RA653 - ZDKF20210401), School of Stomatology, Lanzhou University, No. 199, Donggang West Road, Gansu Province, Lanzhou, 730000, People's Republic of China
- Department of Orthodontics, School of Stomatology, Lanzhou University, No. 199, Donggang West Road, Gansu Province, Lanzhou, 730000, People's Republic of China
| | - Hui Xue
- Department of Stomatology, the Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, No. 242, Guangji Road, Suzhou, 215000, Jiangsu Province, People's Republic of China.
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Yan X, Zhang X, Ren L, Yang Y, Wang Q, Gao Y, Jiang Q, Jian F, Long H, Lai W. Effectiveness of clear aligners in achieving proclination and intrusion of incisors among Class II division 2 patients: a multivariate analysis. Prog Orthod 2023; 24:12. [PMID: 37009943 PMCID: PMC10068686 DOI: 10.1186/s40510-023-00463-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Accepted: 03/14/2023] [Indexed: 04/04/2023] Open
Abstract
BACKGROUND The predictability of incisor movement achieved by clear aligners among Class II division 2 patients is poorly understood. The aim of this retrospective study was to determine the effectiveness of clear aligners in proclining and intruding upper incisors and its influencing factors. METHODS Eligible patients with Class II division 2 malocclusion were included. For clear aligner therapy, three types of incisor movements were designed: proclination, intrusion and labial movement. Pre-treatment and post-treatment dental models were superimposed. The differences between predicted and actual (DPA) tooth movement of incisors were analyzed. Univariate and multivariate linear regression were used to analyze the potential influencing factors. RESULTS A total of 51 patients and their 173 upper incisors were included. Actual incisor proclination and intrusion were less than predicted ones (both P < 0.001), while actual labial movement was greater than predicted one (P < 0.001). Predictability of incisor proclination and intrusion was 69.8% and 53.3%, respectively. Multivariate linear regression revealed that DPA of proclination was significantly positively associated with predicted proclination (B = 0.174, P < 0.001), ipsilateral premolar extraction (B = 2.773, P < 0.001) and ipsilateral canine proclination (B = 1.811, P < 0.05), while negatively associated with molar distalization (B = - 2.085, P < 0.05). The DPA of intrusion was significantly positively correlated with predicted intrusion (B = 0.556, P < 0.001) while negatively associated with labial mini-implants (B = - 1.466, P < 0.001). The DPA of labial movement was significantly positively associated with predicted labial movement (B = 0.481, P < 0.001), while negatively correlated with molar distalization (B = - 1.004, P < 0.001), labial mini-implants (B = - 0.738, P < 0.001) and age (B = - 0.486, P < 0.05). CONCLUSIONS For Class II division 2 patients, predicted incisor proclination (69.8%) and intrusion (53.3%) are partially achieved with clear aligner therapy. Excessive labial movement (0.7 mm) of incisors may be achieved. Incisor movement is influenced by predicted movement amount, premolar extraction, canine proclination, molar distalization, mini-implants and age.
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Affiliation(s)
- Xinyu Yan
- Department of Orthodontics, State Key Laboratory of Oral Diseases and National Clinical Center for Oral Research, West China Hospital of Stomatology, Sichuan University, No. 14, Section 3, Ren Min Nan Road, Chengdu, 610041, China
| | - Xiaoqi Zhang
- Department of Orthodontics, State Key Laboratory of Oral Diseases and National Clinical Center for Oral Research, West China Hospital of Stomatology, Sichuan University, No. 14, Section 3, Ren Min Nan Road, Chengdu, 610041, China
| | - Linghuan Ren
- Department of Orthodontics, State Key Laboratory of Oral Diseases and National Clinical Center for Oral Research, West China Hospital of Stomatology, Sichuan University, No. 14, Section 3, Ren Min Nan Road, Chengdu, 610041, China
| | - Yi Yang
- Department of Orthodontics, State Key Laboratory of Oral Diseases and National Clinical Center for Oral Research, West China Hospital of Stomatology, Sichuan University, No. 14, Section 3, Ren Min Nan Road, Chengdu, 610041, China
| | - Qingxuan Wang
- Department of Orthodontics, State Key Laboratory of Oral Diseases and National Clinical Center for Oral Research, West China Hospital of Stomatology, Sichuan University, No. 14, Section 3, Ren Min Nan Road, Chengdu, 610041, China
| | - Yanzi Gao
- Department of Orthodontics, State Key Laboratory of Oral Diseases and National Clinical Center for Oral Research, West China Hospital of Stomatology, Sichuan University, No. 14, Section 3, Ren Min Nan Road, Chengdu, 610041, China
| | - Qingsong Jiang
- Department of Orthodontics, State Key Laboratory of Oral Diseases and National Clinical Center for Oral Research, West China Hospital of Stomatology, Sichuan University, No. 14, Section 3, Ren Min Nan Road, Chengdu, 610041, China
| | - Fan Jian
- Department of Orthodontics, State Key Laboratory of Oral Diseases and National Clinical Center for Oral Research, West China Hospital of Stomatology, Sichuan University, No. 14, Section 3, Ren Min Nan Road, Chengdu, 610041, China
| | - Hu Long
- Department of Orthodontics, State Key Laboratory of Oral Diseases and National Clinical Center for Oral Research, West China Hospital of Stomatology, Sichuan University, No. 14, Section 3, Ren Min Nan Road, Chengdu, 610041, China.
| | - Wenli Lai
- Department of Orthodontics, State Key Laboratory of Oral Diseases and National Clinical Center for Oral Research, West China Hospital of Stomatology, Sichuan University, No. 14, Section 3, Ren Min Nan Road, Chengdu, 610041, China.
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Hu H, Hu R, Wu G, Sun C. The evaluation of lateral incisor adjacent to treated labial inversely impacted maxillary central incisor: A retrospective follow-up study. Am J Orthod Dentofacial Orthop 2023:S0889-5406(23)00062-8. [PMID: 36842949 DOI: 10.1016/j.ajodo.2022.10.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 10/01/2022] [Accepted: 10/01/2022] [Indexed: 02/28/2023]
Abstract
INTRODUCTION This retrospective study aimed to evaluate the further development of the lateral incisor and its associated periodontium adjacent to the treated labial inversely impacted maxillary central incisor. METHODS We enrolled 23 participants (average age, 8.24 ± 1.43 years) undergoing a mean follow-up period of 31.10 ± 13.05 months. Each participant had an unimpacted lateral incisor and a successfully treated unilateral labial inversely impacted maxillary central incisor. The contralateral lateral incisors served as controls. Cone-beam computed tomography data were available for treatment completion and follow-up stages. The variables (including root length, dental age, root canal width, root-crown angulation, and alveolar bone loss and thickness) were evaluated with Dolphin Imaging software (version 11.95; Dolphin Imaging and Management Solutions, Chatsworth, Calif). RESULTS At the follow-up stage, the lateral incisors in the impacted side had significantly longer root lengths, smaller root canal widths, and thinner labial bone widths at the apex than at the posttreatment stage (P <0.001, P = 0.036, and P = 0.001, respectively). A significant lateral incisor root length reduction was noted when comparing the impacted and contralateral sides, although no variation was observed in root canal width. Similarly, crown-root angulation of the lateral incisor on the impacted side was significantly larger than that of the contralateral lateral incisor. The lateral incisor on the impacted side also had thicker labial and thinner lingual bone widths at the apex than the contralateral lateral incisor. CONCLUSIONS The lateral incisor adjacent to the successfully treated labial inversely impacted maxillary central incisor showed continuous growth during follow-up stages, exhibiting a similar morphology and alveolar bone quality but shorter root length, larger root angulation, and thinner lingual bone width at the apex than those of the contralateral lateral incisors.
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Affiliation(s)
- Han Hu
- Department of Orthodontics, School of Stomatology, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Rongdang Hu
- Department of Orthodontics, School of Stomatology, Wenzhou Medical University, Wenzhou, Zhejiang, China.
| | - Guosheng Wu
- Department of Orthodontics, School of Stomatology, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Chaofan Sun
- Department of Orthodontics, School of Stomatology, Wenzhou Medical University, Wenzhou, Zhejiang, China
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Chen H, Liu L, Han M, Gu Y, Wang W, Sun L, Pan Y, Li H, Wang Z, Sun W, Zhang WB, Wang H. Changes of maxillary central incisor and alveolar bone in Class II Division 2 nonextraction treatment with a fixed appliance or clear aligner: A pilot cone-beam computed tomography study. Am J Orthod Dentofacial Orthop 2022; 163:509-519. [PMID: 37079283 DOI: 10.1016/j.ajodo.2022.02.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 02/01/2022] [Accepted: 02/01/2022] [Indexed: 11/20/2022]
Abstract
INTRODUCTION This retrospective clinical study investigated the clinical changes of maxillary central incisor and alveolar bone in Class II Division 2 nonextraction treatment with fixed appliances or clear aligners on the basis of cone-beam computed tomography. METHODS Fifty-nine Chinese Han patients with similar demographic characteristics were collected from a conventional bracket group, a self-ligating bracket group, and a clear aligner group. All measurements about root resorption and alveolar bone thickness on the cone-beam computed tomography images were tested. Changes between pretreatment and posttreatment were evaluated by paired-sample t test. The variation among the 3 groups was compared by 1-way analysis of variance. RESULTS The resistance center of the maxillary central incisor showed upward or forward movement, and the axial inclination was increased in 3 groups (P <0.0001). Root volume loss in the clear aligner group (23.68 ± 4.82 mm3) was significantly less than that in the fixed appliances group (28.24 ± 6.44 mm3 in the conventional bracket group, 28.17 ± 6.07 mm3 in the self-ligating bracket group) (P <0.05). All 3 groups showed a significant decrease in palatal alveolar bone and total bone thickness at all 3 levels at posttreatment. In contrast, labial bone thickness significantly increased except for crestal level l. Among the 3 groups, the clear aligner group had a prominent increase in labial bone thickness at the apical level (P = 0.0235). CONCLUSIONS Clear aligner treatment for Class II Division 2 malocclusions could effectively reduce the incidence of fenestration and root resorption. Our findings will be beneficial to comprehensively understand the effectiveness of different appliances for Class II Division 2 malocclusions treatment.
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Affiliation(s)
- Hongyu Chen
- Department of Orthodontics, the Affiliated Stomatological Hospital of Nanjing Medical University; Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University; Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, China
| | - Luwei Liu
- Department of Orthodontics, the Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
| | - Minxuan Han
- Department of Orthodontics, the Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
| | - Yan Gu
- Department of Orthodontics, the Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
| | - Wei Wang
- Department of Orthodontics, the Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
| | - Lian Sun
- Department of Orthodontics, the Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
| | - Yongchu Pan
- Department of Orthodontics, the Affiliated Stomatological Hospital of Nanjing Medical University; Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University; Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, China
| | - Hu Li
- Department of Orthodontics, the Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
| | - Zhendong Wang
- Department of Orthodontics, the Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
| | - Wen Sun
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University; Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, China
| | - Wei-Bing Zhang
- Department of Orthodontics, the Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China; Department of Stomatology, Dushu Lake Hospital Affiliated to Soochow University; Department of Stomatology, Medical Center of Soochow University, Soochow, China.
| | - Hua Wang
- Department of Orthodontics, the Affiliated Stomatological Hospital of Nanjing Medical University; Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University; Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, China.
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WANG XM, MA LZ, YAN MF, ZHENG J, WANG M, HUI X. The variation in crown-root morphology of anterior teeth assessed with cone-beam computed tomography. Dental Press J Orthod 2022; 27:e222079. [PMID: 35544841 PMCID: PMC9083280 DOI: 10.1590/2177-6709.27.1.e222079.oar] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 08/31/2020] [Indexed: 11/25/2022] Open
Abstract
Objective: To determine the discrepancy of crown-root morphology of anterior teeth, using cone-beam computed tomography (CBCT), and to provide a guidance for proper torque expression. Methods: A total of eligible 200 CBCT were imported into Invivo v. 5.4 software, to obtain the middle labio-lingual sections of anterior teeth. AutoCAD 2007 software was applied to measure the crown-root angulation (Collum angle) and the angle formed by a tangent to the center of the labial surface and the long axis of the crown (labial surface angle). SPSS 18.0 was used for statistical comparisons of the two measurements, at the level of p< 0.05, and the Pearson correlation analysis was applied to investigate the association between the two measurements. Results: The value of Collum angle in maxillary central incisor was close to 0°. Significantly negative Collum angle in lateral incisors and maxillary canine, and positive value in mandibular canine were detected (p < 0.001). The labial surface angle in canine was significantly greater than the intra-arch incisors (p< 0.001), and no significant difference was detected between the central and lateral incisors (p > 0.05). Notably, there was also a significant positive correlation between the two measurements. Conclusions: The crown-root angulations were greatly different among anterior teeth. Accompanying the obvious crown-root angulations, the canines both in maxillary and mandibular arches presented considerable labial surface curvatures. Hence, equivalent deviation during bracket bonding might cause greater torque expression error and increase the risk of alveolar fenestration and dehiscence.
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Affiliation(s)
| | - Ling-zhi MA
- Stomatological Hospital of Kunming Medical University, China
| | - Mei-fang YAN
- The Affiliated Suzhou Hospital of Nanjing Medical University, China
| | | | - Mi WANG
- The Affiliated Suzhou Hospital of Nanjing Medical University, China
| | - Xue HUI
- The Affiliated Suzhou Hospital of Nanjing Medical University, China
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Chalala C, Saadeh M, Ayoub F. Facial Flatness Indices: A Comparison of Two Methods of Assessment. J Clin Imaging Sci 2020; 10:68. [PMID: 33194310 PMCID: PMC7655991 DOI: 10.25259/jcis_66_2020] [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: 05/08/2020] [Accepted: 10/05/2020] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVES The objective of the study was to evaluate and compare facial flatness indices calculated from the trigonometric formula as opposed to those generated from the direct measurements on three-dimensional radiographs. MATERIAL AND METHODS A total of 322 cone-beam computed tomography radiographs were digitized and three facial indices (frontal, simotic, and zygomaxillary) were assessed in two different methods and compared between different groups. RESULTS There was a discrepancy between facial flatness indices generated from the two different approaches. The highest difference was seen in the findings of the simotic index and the lowest for the zygomaxillary index. No statistically significant difference was displayed in the three formula-generated flatness indices between males and females and between growing and non-growing subjects (P > 0.05). The zygomaxillary index was the only measurement revealing no statistically significant difference in Class III sagittal malocclusions (t = -0.5 P = 0.621). The orthodontic application would yield to the same interpretations for both ways of indices calculation. CONCLUSION The validity of the trigonometric formula used to appraise facial flatness indices might be questionable. The zygomaxillary index could be more clinically considered compared to the frontal and simotic indices.
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Affiliation(s)
- Chimène Chalala
- Department of Orthodontics and Dentofacial Orthopedics, Lebanese University and American University of Beirut, Beirut, Lebanon
| | - Maria Saadeh
- Department of Orthodontics and Dentofacial Orthopedics, Lebanese University and American University of Beirut, Beirut, Lebanon
- Department of Forensic Odontology, Anthropology and Human Identification, Lebanese University, Beirut, Lebanon
| | - Fouad Ayoub
- Department of Forensic Odontology, Anthropology and Human Identification, Lebanese University, Beirut, Lebanon
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Elangovan B, Srinivasan B, Kailasam V, Padmanabhan S. Comparison of the collum angle of incisors and canines in skeletal malocclusions - A CBCT study. Int Orthod 2020; 18:468-479. [PMID: 32800523 DOI: 10.1016/j.ortho.2020.06.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 06/16/2020] [Accepted: 06/17/2020] [Indexed: 10/23/2022]
Abstract
INTRODUCTION The collum angle that defines the crown root angulation of the single rooted teeth plays an important in treatment planning. OBJECTIVE To compare the collum angle (crown root angulation) of maxillary and mandibular anterior teeth in different skeletal malocclusions using Cone Beam Computed Tomography (CBCT). MATERIALS AND METHODS Sixty subjects were categorized into four groups (fifteen subjects in each group) Class I, Class II division 1, Class II division 2 malocclusion and Class III based on Angle classification, Wits and ANB. The collum angle of maxillary and mandibular anterior teeth was measured using CBCT. One way ANOVA, Post hoc comparison with Tukey HSD and Paired t-test were used to analyse the measured data. RESULTS The collum angle of corresponding right and left side teeth were averaged. Thus, the mean and standard deviation of the collum angle (n-30) were generated for maxillary and mandibular central incisors, lateral incisors, and canines. A statistically significant increase was observed in the maxillary central incisors of Class II division 2 and mandibular lateral incisors of class III malocclusion. The collum angle was increased in mandibular canines of Class III malocclusion when compared with class I and Class II division 2 malocclusion. The collum angle was negative in mandibular central incisors of Class II division 2. No statistically significant difference was observed in the mean collum angle between the right and left side anterior teeth in all the four groups. CONCLUSION A variation in Collum angle was observed between the maxillary and mandibular anterior teeth and malocclusions. The effect of these variations in collum angle in torque expression and biomechanics should be kept in mind by the orthodontist before treatment planning especially in Class II division 2 malocclusion.
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Affiliation(s)
- Bharathi Elangovan
- Sri Ramachandra Institute of Higher Education and Research, Department of Orthodontics, Chennai, India.
| | - Bhadrinath Srinivasan
- Sri Ramachandra Institute of Higher Education and Research, Department of Orthodontics, Chennai, India
| | - Vignesh Kailasam
- Sri Ramachandra Institute of Higher Education and Research, Department of Orthodontics, Chennai, India
| | - Sridevi Padmanabhan
- Sri Ramachandra Institute of Higher Education and Research, Department of Orthodontics, Chennai, India
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