Ko E.W.-C.,Chang Gung University |
Lin S.C.,Chang Gung University |
Lin S.C.,Craniofacial Research Center |
Chen Y.R.,Chang Gung University |
Huang C.S.,Chang Gung University
Journal of Oral and Maxillofacial Surgery | Year: 2013
Purpose: The objectives of the study were to identify the parameters related to skeletal stability after orthognathic surgery in skeletal Class III malocclusion using a surgery-first approach and to analyze the factors correlated with surgical relapse. Materials and Methods: Forty-five consecutive patients were included. Serial cephalometric radiographs were traced and superimposed to investigate surgical stability at the initial examination, 1 week postoperatively, and after orthodontic debonding (12.22 mo after surgery). Patient grouping was based on the amount of horizontal relapse at the innermost point of the contour of the mandible between the incisor tooth and the bony chin, the B point (less stable group, n = 15; highly stable group, n = 18). Parameters, such as presurgical skeletal and dental variables, the amount of surgical setback, and total treatment duration, were compared between groups and analyzed for correlations with surgical stability. Results: The mean setback at the innermost point of the contour of the mandible between the incisor tooth and the bony chin was 11.19 mm, and the mean relapse rate was 12.46%. The amount of surgical setback, overbite (positive values), overjet, depth of the curve of Spee, and lower anterior facial height showed statistically significant differences between groups. The amount of surgical setback, overbite (positive values), overjet, and depth of the curve of Spee showed statistically significant correlations with the amount of relapse. Skeletal relapse of the mandible increased significantly as the overbite increased. Conclusion: The factors for instability in the surgery-first approach include a larger overbite, a deeper curve of Spee, a greater negative overjet, and a greater mandibular setback. The initial overbite may be an indicator to predict possible skeletal relapse of mandibular setback. © 2013 American Association of Oral and Maxillofacial Surgeons.
Teng G.Y.Y.,Chang Gung Memorial Hospital |
Liou E.J.W.,Chang Gung Memorial Hospital |
Liou E.J.W.,Craniofacial Research Center |
Liou E.J.W.,Chang Gung University
Journal of Oral and Maxillofacial Surgery | Year: 2014
Purpose Although it has been revealed clinically that double-jaw orthognathic surgery induces a systemic increase in the baseline bone turnover and subsequently accelerates postoperative orthodontic tooth alignment, it is not clear whether less extensive osteotomy, such as interdental osteotomy, would be intensive enough to accelerate postoperative orthodontic tooth alignment. Materials and Methods Twelve adult male beagle dogs were randomly assigned to 2 groups. The sham control group (n = 6) received orthodontic tooth alignment of the maxillary incisors, and the experimental group (n = 6) received orthodontic tooth alignment of the maxillary incisors and interdental osteotomies between the maxillary third incisor and canine on both sides concurrent with the beginning of orthodontic tooth alignment. The duration of orthodontic tooth alignment was 3 months in both groups. Cone-beam computed tomography scans of the maxilla, dental casts, blood samples, and gingival crevicular fluid (GCF) of the maxillary incisors were taken immediately before orthodontic tooth alignment (T0) and 1 week (T1) and 1 (T2), 2 (T3), and 3 (T4) months after beginning orthodontic tooth alignment. They were analyzed for changes in the interdental alveolar bone gray scale (osteoporosity) of the maxillary incisors, irregularity index (rate of orthodontic tooth alignment), and bone-specific alkaline phosphatase (bALP, a biomarker of osteoblastic activity) and C-terminal telopeptide of type I collagen (ICTP, a biomarker for osteoclastic activity) in the serum and GCF samples from T0 to T4. The data were analyzed statistically for inter- and intragroup differences. Results The rate of orthodontic tooth alignment for the experimental group was significantly greater and twofold that of the sham control group at T1, T2, T3, and T4. The serum-bALP, serum-ICTP, GCF-bALP, GCF-ICTP, and osteoporosity remained similar from T0 to T4 in the sham control group. In contrast, GCF-bALP increased two- to threefold from T1 to T4, and GCF-ICTP increased fivefold at T1 and then gradually decreased from T2 to T4. The interdental osteoporosity significantly increased from T1 to T4, but the serum-bALP and serum-ICTP levels remained similar, without significant changes in the experimental group. Conclusions Interdental osteotomy induced a regional, but not a systemic, acceleratory phenomenon and was intensive enough to accelerate postoperative orthodontic tooth alignment twofold. The intensity of the increase in the bone turnover rate and osteoporosity might depend on the extent of the osteotomy. © 2014 Published by Elsevier Inc on behalf of the American Association of Oral and Maxillofacial Surgeons. All rights reserved.
Lin H.-H.,National Chung Hsing University |
Lin H.-H.,Craniofacial Research Center |
Shu S.-G.,Chung Shan Medical University |
Lin Y.-H.,National Chung Hsing University |
Yu S.-S.,National Chung Hsing University
Pattern Recognition | Year: 2012
There are different feature selections in a bone age assessment (BAA) system for various stages of skeletal development. For example, diameters of epiphysis and metaphysis are used as sensitive factors during the early stage. Once the epiphyseal fusion has started, an additional feature such as the degree of fusion is extracted at the later stage. Image analysis is a critical point for feature selections to get a fine BAA, which includes ROI processing and feature extraction. Nevertheless, the related modeling techniques are various depending on the characteristics of different stages of bone maturity, which usually are taken as a priori knowledge in most previously proposed schemes. If a coarse bone age cluster (stage) for a hand radiograph could be automatically pre-assigned, then these corresponding image analysis methods can be identified. This could avoid taking a priori knowledge and provide a more flexible and reliable BAA system. For this purpose, a bone age cluster assessment system using fuzzy neural network (FNN) based on phalangeal image rough segmentation is presented in this work. This system includes two parts. The first part adjusts the feature weights to stable conditions according to four new defined bone age stages, which satisfy feature development of epiphysis and metaphysis. The second part is bone age cluster assessment on hand radiography based on the results of the first part. Experimental results reveal that the presented FNN system provides a very good ability to assign a hand radiograph to an appropriate bone age cluster and demonstrates the rationality of those new defined stages. Furthermore, the related feature clustering analysis for various stages is discussed to provide an accurate quantitative evaluation of specific features for the final BAA. © 2011 Elsevier Ltd. All rights reserved.
Hsieh Y.-J.,Chang Gung Memorial Hospital |
Hsieh Y.-J.,Craniofacial Center |
Hsieh Y.-J.,Craniofacial Research Center |
Liao Y.-F.,Chang Gung Memorial Hospital |
And 3 more authors.
British Journal of Oral and Maxillofacial Surgery | Year: 2013
Obstructive sleep apnoea is ideally treated by continuous positive airway pressure, but other options are needed because its clinical effectiveness is limited by poor acceptance and tolerance, which results in suboptimal compliance. Patients often prefer operation, with maxillomandibular advancement (MMA) being the most effective approach. In this systematic review we have assessed its effects on the upper airway and surrounding structures in patients with obstructive sleep apnoea. After a structured search of electronic databases and hand searching, we retrieved 104 publications. After application of inclusion and exclusion criteria, 15 studies remained. From these we extracted data on study design, sample size, patients, methods and measurement, and outcomes. The quality of each study was assessed objectively. The heterogeneity of samples and outcome measures prevented a meta-analysis. MMA was shown to be an effective treatment of sleep apnoea. Primary and secondary MMA resulted in mean reductions in the apnoea-hypopnoea index/respiratory disturbance index of 61-92% and 82-92%, respectively. The operation not only enlarges the upper airway in the anteroposterior and lateral dimensions, but also raises the hyoid. Only 7 studies reported the relations between improvement in sleep apnoea and changes in the upper airway and surrounding structures, and only one correlated it with skeletal advancement. The studies were of low or medium quality. There were insufficient data to support a relation between improvement in sleep apnoea and changes in the upper airway and surrounding structures because of the contradictory results and poor quality of most studies. © 2012 The British Association of Oral and Maxillofacial Surgeons.
Huang C.S.,Craniofacial Research Center |
Huang C.S.,Chang Gung University |
Liu X.Q.,Qingdao University |
Chen Y.R.,Chang Gung University |
Chen Y.R.,Craniofacial Research Center
Orthodontics and Craniofacial Research | Year: 2013
Objectives: To differentiate a symmetric face from an asymmetric face by analyzing a three-dimensional (3D) facial image and plotting the asymmetry index (AI) on a facial symmetry diagram. Setting and Sample Population: Sixty healthy Chinese adults (30 men and 30 women, mean age: 27.7 + 4.9 years old) without any craniofacial deformity were recruited on a voluntary basis from a medical center. Material and Methods: A 3D facial image of each participant was captured by a GENEX 3D FACE CAM system. Sixteen facial landmarks, as defined by Farkas, were selected on each 3D facial image. The AI was calculated for each landmark. Results: The norm for the AI varied from 0.76 to 2.82. The landmarks located on the upper face had a smaller AI than the landmarks located on the lower face. A facial symmetry diagram was designed according to the mean, one standard deviation, and 2 standard deviations of AI for each landmark. Conclusions: The 3D facial asymmetry can be documented with AI. The landmarks located on the upper face had a smaller AI than the landmarks located on the lower face. The facial symmetry diagram can identify efficiently the location of asymmetry on a face. © 2012 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.