Application of Cephalometric Analysis To Surgical Treatment of Dentofacial Deformities

In view of orthognathic surgery,on the basis of the ccphalometric data of the youths innorth-west China,the most common 29 parameters were chosen,including angles,linear measureand ratio.For analysis,they were divided into four groups:general profile feature,maxilla andorbital-zygomatic regio,mandible and chin.This kind of analysis can be usecd for clinicaldiagnosis and for detemining the nature,position and degree of the dcformities.It is espceially effec-five in the designing of operation and prediction of the result of the surgery.

Research and Application on Automatic Cephalometric Measurement and Facial Prediction System

In this paper, a practical automatic cephalometric measurement and facial prediction system is built by using adaptive filtering and edge detecting techniques and some artificial intelligent approaches. The system not only realizes the automation from landmark location to parameter measurement on cephalogram, but also makes the diagnostic design of preoperation of orthognathic surgery quantitive. Compared with the manual prediction, it provides a new method to make the diagnosis and treatment for deto maxillofacial deformities more accurate. It is more significant to clinical application and scientific research.

STEINER CEPHALOMETRIC NORMS FOR SHANGHAI ADULT

In this paper, 60 samples (30 male and 30 female) with normal occlusion in permanent dentition were selected. 60 lateral radiographic cephalograms were taken. By mean of Steiner analysis, means, standard deviations were calculated. Acceptable compromises for individual use were established. Comparison these data with Beijing and Korean were made. Thus the characteristics of craniofacial morphology and denture patterns of Shanghai adult were observed.

Researchon the Correlativity between SevenCephalometric Indexes for Evaluation of theMaxillomandibular Sagittal Relationship

An analysis of the correlativity between seven cephalometric indexes of SN. FH and OP systems indicates that none of the systems possesses the index which can rule out the effects of other factors to evaluate objectively the sagittal relation between the jaws. In these three systems, owing to more factors affecting indexes of SN system, we suggest to use AXB or A-B/ /FH and Wit's appraisal in comprehensive analysis of the sagittal relation of the jaws, instead of the indexes of SN system. Using indexes of FH or OP system alone in evaluation of not advocated.

Cephalometric norms for a sample of Emirates adults

Introduction—European-American norms are still used in the orthodontic treatment of Emirates patients despite the different ethnic backgrounds of the Emirates. The purpose of this study was to formulate cephalometric norms for lateral cephalometric mea-surements of Emirates adults and to study gender differences. Methods—Lateral cephalometric radio-graphs of 176 Emirates adults, 91 males and 85 fe-males, were selected according to the following crite-ria;an age range between 19 to 25 years, esthetically pleasing and harmonious faces with balanced and acceptable profiles and occlusions, normal skeletal and dental relationship, all permanent teeth present, and no history of orthodontic treatment or facial trauma. The mean values and standard deviations of 91 angular and 21 linear cephalometric variables were calculated using the Dolphin version 10.5 soft-ware package. The resulting norms for Emirates male and female groups were compared using a student t-test. Results—Several statistically significant gender differences were noticeable. Skeletally, Emirates males showed significantly greater (p < 0.001) total, anterior, and posterior cranial base lengths as well as longer facial heights, greater SGn-FH (°), ANS Xi PM (°),and FH/MP (°) angles than females. In addition, Emirates males had significantly greater (p < 0.001) Co-A (mm), Co-Gn (mm), and significantly greater (p < 0.05) Pog-N vert (mm) than females. Dentally, Emirates males had significantly greater (p < 0.05) UI-SN (°) and U1-NA (°), U1-NA (mm), and L1-NB (mm) (p < 0.001) than females. For soft tissue measurements there were significant gender differences (p < 0.001) for all angular and linear measurements except for lower lip to E-plane and nose prominence measurements which have no significant gender difference. Emirates males revealed greater measurements than females except for soft tissue con-vexity, Z-angle, and both upper and lower lips pro-trusion which were significantly greater in Emirates females. Conclusions—The use of specific cephalometric standards for Emirates adults, sep-arate for gender, seems to be justified. It is appropri-ate to put these cephalometric norms into daily or-thodontic practice when Emirates adults are being treated.

Evaluation of the Role of Palatal Tonsil Hypertrophy in Sleep Apnea Patients: Cephalometric Analysis

The purpose of this research was to elucidate the relationship between tonsillar hypertrophy and Obstructive Sleep Apnea Syndrome (OSAS) in terms of cephalometric analysis, as well as to determine factors that affect OSAS severity. 25 patients were enrolled in this study. Lateral cephalograms of the subjects were taken. Disease severity was evaluated by the Apnea Hypopnea Index (AHI). Cephalometric measurements (angle between line S-N and line N-A (SNA), angle between line S-N and line N-B (SNB), distance between the Mandibular Plane and the Hyoid (MPH), posterior airway space, the width of the airway behind the base of tongue along the B-Go line (PAS), upper airway space, the distance parallel to long axis of the airway, between a horizontal plane tangent to the superior aspect of the hyoid and a horizontal plane tangent to the posterior palate (UAL), multiplication of PAS and UAL (PAS × UAL)) were analyzed and compared between the groups with and without tonsillar hypertrophy. PAS and PAS × UAL were lower in the no hypertrophy group. SNB was significantly lower in the severe apnea group than mild to moderate group in no hypertrophy group (p = 0.035). In conclusion, patients with tonsillar hypertrophy had severe obstruction, but they had a relatively larger pharyngeal space on cephalometric analysis. After exclusion of the tonsillar hypertrophy group, cephalometric analysis could be more effective for analyzing OSAS severity.

Robust ACO-Based Landmark Matching and Maxillofacial Anomalies Classification

Imagery assessment is an efficient method for detecting craniofacial anomalies.A cephalometric landmark matching approach may help in orthodontic diagnosis,craniofacial growth assessment and treatment planning.Automatic landmark matching and anomalies detection helps face the manual labelling lim-itations and optimize preoperative planning of maxillofacial surgery.The aim of this study was to develop an accurate Cephalometric Landmark Matching method as well as an automatic system for anatomical anomalies classification.First,the Active Appearance Model(AAM)was used for the matching process.This pro-cess was achieved by the Ant Colony Optimization(ACO)algorithm enriched with proximity information.Then,the maxillofacial anomalies were classified using the Support Vector Machine(SVM).The experiments were conducted on X-ray cephalograms of 400 patients where the ground truth was produced by two experts.The frameworks achieved a landmark matching error(LE)of 0.50±1.04 and a successful landmark matching of 89.47%in the 2 mm and 3 mm range and of 100%in the 4 mm range.The classification of anomalies achieved an accuracy of 98.75%.Compared to previous work,the proposed approach is simpler and has a comparable range of acceptable matching cost and anomaly classification.Results have also shown that it outperformed the K-nearest neigh-bors(KNN)classifier.

Clinical Effect of Tip-Edge plus Appliance in Children with Angle Ⅱ1 Malocclusion

The effects of Tip-Edge plus appliance in the treatment of Angle Ⅱ1 malocclusion and the mechanism were investigated. Fifty-two Angle Ⅱ1 children, aged from 12.3-14.2 years, with mandibu- lar retrusion in permanent dentition were selected and treated with Tip-Edge plus appliance. Lateral cephalometric films taken before and after treatment were analyzed. The arithmetic mean and standard deviation were calculated for each variable. Paired t-test was performed to evaluate the significant treatment change. Results showed that the average treatment time was 16 months. Normal overjet and overbite were established with retroclination of upper incisors and proclination of lower incisors. U1-NA was decreased by 15.4° （P〈0.01）. ANB and Y axial angle were decreased significantly （P〈0.05） Soft tissue measurements showed that FCA and UL-E were decreased dramatically （P〈0.05）, and LL-E was increased significantly （P〈0.05）. Remarkable soft tissue change was noted after the treatment and convex facial profile changed to the straight profile. In conclusion, Tip-Edge plus technique can quickly and efficiently correct anterior bite and lateral outlook.

A Comparison between 2D and 3D Images to Study Maxillary and Mandibular Widths: A Pilot Study

The objective of this study is to compare the transverse dimensions of the jaws, obtained from traditional posteroanterior (PA) cephalometric radiographs, and with the similar respective measurements obtained by means of cone beam computed tomography (CBCT). Data of twelve subjects were selected from the clinical records of Orthodontic Department. All of the subjects had their permanent teeth in occlusion and had good quality regular (2D), and CBCT (3D) images as part of their initial records. Subjects were divided to a posterior cross-bite and non-cross bite groups. The ratio of the maxillary, to mandibular transverse widths was calculated for the sample. In subjects without dental cross-bites the average ratio of the maxillary, to mandibular jaw widths was 0.75 on the standard radiographs and 1.04 on the CBCT scans. In subjects with dental cross-bites the average ratio of these widths was 0.70 on the standard radiographs and 0.9 on the CBCT scans. The ratios of the maxillary, to mandibular widths differ when obtained from conventional cephalometric radiographs as compared to the respective ratios obtained from CBCT scans. Maxillary, to mandibular width ratio is in the order of 1:1 as determined by means of CBCT scans.

Adaptive Kalman Filtering Approach of Color Noise in Cephalometeric Image

A kind of adaptive color noise Kalman filtering approach based on the correlative method of the system output is proposed to solve the cephalometric images of stomatology. This approach builds the color noise Kalman filtering model by adopting the equivalent measurement equation in order to aviod complicated computation and expansion of the dimension of the filter. It is also unnecessary to know the variance of measurement noise beforehand so that it is closer to the actual situation. The results of several experiments are presented to demonstrate the feasibility and good performance of this approach.

A Therapeutic Concept by “Watted” for the Surgical Lengthening of the Lower Face by Short Face Syndrome

The continuously growing esthetic awareness for the facial appearance and the spreading of information about the possibilities of adult treatment by public media result in an increase of adult patients which seek orthodontic treatment to improve their facial esthetics. In general, these patients show such a severe skeletal deformity that it is detectable even by non-experts because of its extraoral manifestation, which is the main motivation for treatment. Because of the nature of these deformities and because of the lacking growth usable for therapy the only promising treatment for these patients is the combined orthodontic-surgical approach. Besides a stable and functional occlusion with physiologic position of the condyle, the goals of treatment are the improvement of the dental and, above all, facial esthetics since the patient judges the success of treatment mostly by the extraoral appearance. The dentofacial appearance must be defined prior to treatment to plan the individual right approach in knowledge of the different treatment possibilities for Angle Class II deformities and thus be able to reach for both sides—patient and orthodontist—satisfying result. With this article, a systematic therapy concept to treat patients with Class II deformities and skeletal deep bite with a short lower face (short face syndrome) under consideration of the soft tissue analysis is presented.