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Background The aim of this study was to cephalometrically evaluate and compare a treatment protocol in patients with Class II Division 1 (II/1) and Class II Division 2 (II/2), and to pursue predictors of the change in chin prominence. Methods This retrospective study included 30 patients with Class II/1 and 25 patients with Class II/2 treated with the Forsus appliance, in combination with fixed appliances. Pre- and posttreatment lateral cephalometric radiographs were collected, and 28 measurements were recorded. A two-sample t test was used for the pretreatment comparison among the two Divisions. Paired t tests were used to evaluate the treatment changes within each group. Analysis of covariance was used to compare the treatment changes between the Divisions after adjusting for the baseline value, age, gender, treatment duration, and time with the Forsus appliance. The Simes multiple testing procedure permitted adjustment for multiple comparisons. Regression analysis was performed to identify predictors explaining the change in chin prominence. Results Class II correction occurred in both Divisions, mainly through dentoalveolar effects. There were no significant cephalometric differences found in the mean treatment changes between the Divisions. The pretreatment Gonial angle, molar eruption, lower incisor inclination, mandibular body length, and soft tissue chin thickness had a significant impact on the treatment changes in chin prominence. Conclusions Treatment with the Forsus in combination with preadjusted fixed appliances leads to a favorable treatment outcome and produces similar treatment changes in both Class II Divisions.

Purpose The purpose of this study was to investigate the relationship between changes in three-dimensional (3D) facial morphology and mandibular movement after orthognathic surgery. We hypothesized that facial morphology changes after orthognathic surgery exert effects on 3D mandibular movement. Materials and methods We conducted a prospective follow-up study of patients who had undergone orthognathic surgical procedures. Three-dimensional facial morphological values were measured from facial CT images before and three months after orthognathic surgery. Three-dimensional maximum mandibular opening (MMO) values of four points (bilateral condylions, infradentale, and pogonion) were also measured using a mandibular movement tracking and simulation system. The predictor variables were changes in morphological parameters divided into two groups (deviated side (DS) or contralateral side (CS) groups), and the outcome variables were changes in the MMO at four points. Results We evaluated 21 subjects who had undergone orthognathic surgical procedures. Alterations in the TFH (total facial height), LFH (lower facial height), CS MBL (mandibular body length), and DS RL (ramus length) were negatively correlated with changes in bilateral condylar movement. The UFH, DS MBL and CS ML (mandibular length) showed correlations with infradentale movement. The CS ML, DS ML, MBL, UFH, and SNB were correlated with pogonion movement. Conclusion The height of the face is most likely to affect post-operative mandibular movement, and is negatively correlated with movement changes in the condyles, infradentale and pogonion. The changes in CS morphological parameters are more correlated with mandibular movement changes than the DS. The changes in CS MBL and bilateral RL were negatively correlated with condylar movement changes, while the bilateral MBL and CS ML were positively correlated with changes in infradentale and pogonion.

Purpose The present study was designed to analyze the skeletal differences in patients with temporomandibular joint (TMJ) disc displacement (DD), according to the sagittal jaw relationship. Materials and Methods We implemented a cross-sectional study design and enrolled a sample of Korean women older than age 17 years. The subjects were classified into 3 groups according to the magnetic resonance images of the bilateral TMJs: bilateral normal disc position (BN), bilateral disc displacement with reduction, and bilateral disc displacement without reduction. Each group was subdivided into 2 groups using the mandibular body length to anterior cranial base ratio as a sagittal jaw parameter: normal-size mandible (NM) and oversized mandible (OM). Seventeen variables from the lateral cephalograms were analyzed using 2-way analysis of variance to analyze the differences in skeletal characteristics with respect to the mandible size and TMJ DD status. Results The subjects with TMJ DD generally had a short ramus height and clockwise rotation of the ramus and mandible compared with those with BN in both OM and NM groups. However, significant differences were present in the skeletal characteristics of the TMJ DD patients between the NM and OM groups. Significant backward positioning and rotation of the ramus and mandible were found between BN and bilateral disc displacement with reduction or bilateral disc displacement without reduction in the OM group, while those of the ramus and mandible were found between BN and bilateral disc displacement with reduction or bilateral disc displacement without reduction in the NM group. Conclusions The results of our study suggest that the skeletal characteristics associated with TMJ DD are differently represented according to the sagittal jaw relationship.

Background: This study was undertaken to investigate the facial skeletal features associated with chin deviation. Methods: Twenty-five patients (14 males and 11 females) diagnosed with chin deviations of more than 2 mm were recruited. Fifteen skeletal landmarks, including median and lateral points, were located on posteroanterior cephalograms. The CG–ANS (crista-galli of the ethmoid–anterior nasal spine) line and the perpendicular line through the CG were used as references. The differences between the distances from paired lateral points to reference lines were examined with intraclass correlation coefficients to analyze the symmetry of facial skeletal tissue. The factors associated with the amount or direction of chin deviation were analyzed by multiple regression analysis or by logistic regression analysis. Results: Seventeen subjects (68%) showed chin deviation to the left side and 8 subjects (32%) to the right side. Sixtyeight percent of subjects presented with Angle Class III malocclusion. Horizontal distances of all paired lateral points to the y-axis, in mandibular body length and effective length, showed a low grade of symmetry. Only vertical distances of paired zygomaticofrontal sutures and zygonion points to the x-axis were asymmetric. However, there were no significant asymmetries of the gonial angle, ramus height, and vertical distances from other paired lateral points to the x-axis. The amount of chin deviation was associated with the absolute differences of the left and right antegonion to the y-axis and zygomaticofrontal suture to the x-axis. The direction of chin deviation was significantly associated with the difference in the effective length of bilateral mandibular halves. Conclusion: Facial skeletal asymmetry exists in patients with chin deviation. This should be considered when planning treatment for both the nonsurgical and surgico-orthodontic cases with chin deviation. [J Chin Med Assoc 2010;73(1):29–34]

Summary Background This study was to evaluate the stability of the bioabsorbable plate used in the orthognathic surgery for patients with prognathic mandibles and to evaluate the relapse tendency after surgery and the factors affecting the relapse. Materials and methods The sample consisted of 30 subjects (14 males and 16 females) who underwent bilateral sagittal split ramus osteotomy (BSSRO) for mandibular setback using the poly-l/dl-lactide plate system (Biosorb FX ® , Linvatec Biomaterials Ltd., Tampere, Finland). The lateral cephalometric radiographs of each subject were taken pre-operatively within 1 month (T0), post-operatively within 1 month (T1), and post-operatively between 4 and 10 months (T2) and skeletal changes were analyzed with V-Ceph (CyberMed ® , Seoul, Korea) software. The changes between T1 and T2 were evaluated with a paired t -test to estimate the stability of the surgery. The post-operative changes of mandibular body length and ramus height were used for a K-means clustering analysis to separate subjects into either the less changed (LC), or the more changed (MC) group. The two groups were compared with T0 and the surgical changes (T1−T0) using the t -test. Results Significant relapse after surgery was shown in vertical measurements but not in the horizontal plane measurements. The MC group showed significantly more vertical operative changes than the LC group independent of horizontal measurements. Conclusions Usage of a bioabsorbable plate in mandibular setback surgery could provide stable fixation in the horizontal dimension, but also may allow an increase of vertical relapse due to the increase in vertical dimension post-operatively.

The purpose of this retrospective case-control study was to compare the cephalometric features of parents of children with cleft anomalies to those of parents of normal children in the hope of finding potential markers of predisposition for this condition. There were 22 sets of parents of cleft children (study group) and 22 sets of parents of normal children (control group). A total of 88 lateral cephalograms were traced twice by two observers separately and analyzed using Student's t-test. Seven linear, two angular and five triangular cephalometric variables were measured. Mandibular body length (Go-Gn) in mothers was larger in the study than the control group, posterior cranial base (S-Ba) in fathers was shorter in the study than the control group, anterior maxillary triangle (S.N.A) in parents in the study group was larger than in the control group and posterior maxillary triangle (S.N.Pns) in study group mothers was larger than in control group mothers. In conclusion, the craniofacial morphology of the parents of children with cleft anomalies differs from that of parents of normal children and may have some predictive value.

Legitimate questions exist concerning the degree to which routine orthodontic treatment alters face form. To the extent that such alterations do occur, the delivery of different vectors should result in different sorts of skeletal change. In this study, we have attempted to discern and quantify differences in the rates of change of nine linear measures of mandibular and facial proportions during the course of Phase 1 treatment for the correction of Class II mixed-dentition malocclusion. The analysis took the form of a series of computer-conducted tests performed upon a previously reported tape-stored numerical data base which had been constructed earlier by digitizing pre- and posttreatment lateral cephalograms for a large group of Class II subjects. Rates of change for the nine linear measures were computed separately for samples of subjects treated with cervical face-bow, high-pull face-bow, and activator type intraoral appliances as well as for a control group of untreated Class II subjects. Statistically significant between-treatment differences which we believe are large enough to be of clinical importance were detected for several measures. As compared to the control group, a statistically significant rate of increase in condyle-pogonion distance was found in the intraoral group. Such an observation is consistent with the hypothesis of treatment-associated alteration of growth pattern in the region of the condyle. To our considerable surprise, the cervical group exhibited a similar statistically significant rate of increase in condyle-pogonion distance which is as yet unexplained. In general, rates of increase in measures of anterior face height had higher values in the cervical group than in the control group, implying that consideration should be given to avoiding the use of this treatment modality in patients for whom facial elongation during treatment would be undesirable. The cervical group also exhibited a statistically significant rate of increase in ramus height. Such an effect would tend to keep mandibular plane orientation relatively unchanged in the presence of increase in anterior face height, helping to explain our previously reported findings as to the relative constancy of mandibular plane angle. In the high-pull-treatment group, rates of increase in ramus height and condyle-pogonion distance were significantly lower than those in the control group and rates of increase in lower face height and anterior face height were significantly lower than those in the cervical group. In all three treatment groups, the rate of increase in mandibular body length was less than in the untreated control group, though only in the cervical group was this effect large enough to be statistically significant.