Does skeletal surgery for asymmetric mandibular prognathism influence the soft tissue contour and thickness?

PURPOSE: The purpose of the present study was to investigate whether asymmetric mandibular prognathism accompanies a fundamental difference in soft tissue thickness and whether asymmetric mandibular setback surgery would influence the contour and thickness of the soft tissue of the chin. MATERIALS AND METHODS: The present retrospective study included skeletal class III patients with significant mandibular chin deviation greater than 6 mm at the pogonion, who had undergone cone-beam computed tomography before and 6 months after surgery during a 2-year period. The predictor variables were timing (pre- and postoperatively) and side (asymmetric vs contralateral). The outcome measures were the hard and soft tissue contours and soft tissue thickness of the chin at the infradentale, B-point, and pogonion level evaluated with reformatted computed tomography images. The study variables were statistically compared using regression model and correlation analysis. RESULTS: The present study consisted of 20 patients (10 males and 10 females; average age 20.2 years; range, 18 to 25). Preoperatively, the chin deviation side showed a more prominent hard and soft tissue outline but had a thinner soft tissue thickness, which camouflaged the hard tissue asymmetry. After surgery, the hard and soft tissue outline was greatly improved, and the soft tissue thickness had become nearly symmetric. Most of the soft tissue thickness changes correlated negatively with the hard tissue changes. CONCLUSIONS: Asymmetric mandibular prognathism accompanied the 3-dimensional soft tissue contour and thickness asymmetry. Because the soft tissue responds favorably after skeletal surgery, the correction of 3-dimensional asymmetry of bone should be emphasized in patients with asymmetric mandibular prognathism.

Prevention of cleft lip and/or palate in A/J mice by licorice solution.

Cleft lip and/or palate anomalies (CL ± P) are the most frequent birth defects affecting the orofacial region in humans. Although their etiology remains unclear, the involvement of environmental and genetic risk factors is known. This observational study aimed to investigate how the use of  crude drugs with estrogen activity influenced an animal model's ability to prevent CL ± P. A/J mice were randomly divided into six experimental groups. Five of these groups consumed a drink containing crude drug licorice root extract, with the following weights attributed to each group: 3 g in group I, 6 g in group II, 7.5 g in group III, 9 g in group IV, and 12 g in group V, whereas a control group consumed tap water. The effect of licorice extract was examined for fetal mortality and fetal orofacial cleft development compared to the control group. The rates for fetal mortality were 11.28%, 7.41%, 9.18%, 4.94%, and 7.90% in groups I, II, III, IV, and V, respectively, compared to 13.51% in the control group. There were no significant differences in the mean weight of alive fetuses in all five groups compared to the control group (0.63 ± 0.12). Group IV showed the lowest orafacial cleft occurrence of 3.20% (8 fetuses) with statistical significance (p = 0.0048) out of 268 live fetuses, whereas the control group had the occurrence of 8.75% (42 fetuses) among 480 live fetuses. Our study showed that the dried licorice root extract may reduce orofacial birth defects in experimental animal studies.

Mutations in BMP4 are associated with subepithelial, microform, and overt cleft lip.

Cleft lip with or without cleft palate (CL/P) is a complex trait with evidence that the clinical spectrum includes both microform and subepithelial lip defects. We identified missense and nonsense mutations in the BMP4 gene in 1 of 30 cases of microform clefts, 2 of 87 cases with subepithelial defects in the orbicularis oris muscle (OOM), 5 of 968 cases of overt CL/P, and 0 of 529 controls. These results provide confirmation that microforms and subepithelial OOM defects are part of the spectrum of CL/P and should be considered during clinical evaluation of families with clefts. Furthermore, we suggest a role for BMP4 in wound healing.

Evaluation of pterygomaxillary anatomy using computed tomography: are there any structural variations in cleft patients?

PURPOSE: Structural characteristics of the pterygomaxillary region in patients with cleft lip and palate (CLP) have not been fully investigated. This study aimed to evaluate the regional anatomy of the pterygomaxillary junction of patients with CLP using computed tomography. MATERIALS AND METHODS: The pterygomaxillary structures of patients with unilateral or bilateral CLP were compared with those of a control group using axial computed tomography. The thickness and width of the pterygoid plate, the distance from the greater palatine foramen to the lateral pterygomaxillary junction, the lateral and medial pterygoid plate lengths, and the maxillary posterior transverse width were investigated with axial computed tomography just beneath the level of the inferior nasal concha and approximately 3 to 5 mm above the nasal floor. The difference between the cleft and noncleft sides or the right and left sides of each group and the measurement differences between the groups were statistically compared. RESULTS: The study group was composed of 14 patients with unilateral CLP and 6 with bilateral CLP, and the control group were 20 age- and gender-matched patients with skeletal Class III without CLP. Patients with unilateral CLP and those with bilateral CLP were statistically equivalent for all radiographic variables. In patients with CLP, the width of the pterygomaxillary region and the greater palatine foramen region were on average 1.5 to 1.8 mm larger than in control patients (P < .05). Lateral pterygoid plate length and maxillary posterior transverse width were similar in the 2 groups. However, the patients with CLP showed a 2.3-mm shorter medial pterygoid length (P < .05). CONCLUSION: Patients with CLP had larger and thicker pterygomaxillary dimensions, and the results imply that careful attention to pterygomaxillary anatomy is needed in patients with CLP undergoing Le Fort I surgery.

Three-dimensional facial morphology, following primary cleft lip repair using the triangular flap with or without rotation advancement.

INTRODUCTION: There are numerous methods of repairing a cleft lip. In our institution, two methods have been used for primary lip repair, the triangular flap method, and the rotation-advancement plus small triangular flap method. The purpose of this study was to compare postsurgical anthropometric results following these two surgical methods. PATIENTS: Twenty children with a unilateral complete cleft lip, alveolus and palate (UCLAP) were selected for this study. Ten underwent primary lip repair by the triangular flap method (Triangular Group), and the other 10 underwent repair by the rotation-advancement plus small triangular flap method (Rotation Group). METHOD: They were documented with a three-dimensional optical scanner, and analysed with computer-aided anthropometric method reported previously (Comput. Methods Programs 58: 159-173, 1999a; J. Cranio-Maxillofac Surg 27: 345-353, 1999b). RESULTS: The shapes of the nose and nostril were a little better in the Rotation Group. However, in the Rotation Group, differences between good and poor cases were more extreme than in the Triangular Group. The shape of Cupid's bow was good shortly after surgery in the Triangular Group. A good shape of Cupid's bow was also obtained in the Rotation Group, but the improvement was more delayed. On the non-cleft side, the length of Cupid's bow was more extended in the Triangular Group. Certain deformities were common to both groups, such as deviation of the columella and a flattened ala on the cleft side. CONCLUSION: Rotation-advancement plus the small triangular flap method was thought to produce somewhat better results, however, further improvements in the technique are needed.

Development of a simulation system in mandibular orthognathic surgery based on integrated three-dimensional data.

PURPOSE: Surgical simulation should reflect the 3D movement of dentition and the resultant movement of the osteotomized segments, which can influence surgical outcome. The present study was aimed at developing a new simulation system that enables virtual osteotomy of a given surgical situation and evaluation of the bony interference between the osteotomized segments of the mandible. SUBJECTS AND METHODS: The data of 3D computer tomography (CT) for maxillomandibular dental casts were integrated into the standard coordinates of a 3D cephalogram. To evaluate the accuracy of the system, measurement errors of the 3D CT virtual model from a dry skull were compared with the computer simulation system and a contact-type 3D digitizer. To examine the clinical accessibility, 15 mandibular prognathism patients with mild to severe asymmetry were evaluated with the simulation program. RESULTS: The average error of measurement in all directions was 1.31 mm. It was possible to simulate various osteotomy procedures by conversion of the 3D coordinates of the dental cast and CT data into the standard coordinate system of a 3D cephalogram. Using this simulation system, it was possible to prevent condylar torque or segment malpositioning by removing the bony interference visualized by a 3D virtual model. CONCLUSION: A new system, which enables the precise visualization of osteotomized segments and calculation of bony interference, was proposed in the present study. This new system provides an acceptable precision of treatment planning of orthognathic surgery, especially for facial asymmetry.

Diagnosis and treatment of an infant case with temporomandibular joint osteoarthritis caused by tumor.

INTRODUCTION: We reported an infant with temporomandibular joint (TMJ) osteoarthritis who required long-term tracheostomy. CASE FINDINGS: At 1 year of age, he received urgent tracheostomy because of apnea due to pneumonia. The tracheal cannula could not be removed thereafter due to trismus. Computed tomography (CT) images demonstrate irregular bone formation. However, we could not diagnose osteoarthritis of temporomandibular joint because TMJ adhesion was not clear on CT images. INTERVENTIONS: Arthroplasty was performed under general anesthesia, but there was no significant improvement. A 3-D plastic model based on intraoperative findings showed that atrophic change of the muscles also disturbed movement of the mandible. Therefore, an additional procedure called "pan-muscle-release surgery" was performed, resulting in further improvement of mandible movement. After confirming that mouth opening was stable, the tracheal cannula was removed.

Maxillary distraction osteogenesis in cleft lip and palate patients with skeletal anchorage.

OBJECTIVE: Maxillary distraction osteogenesis with the rigid external distraction (RED) system has been used to treat cleft lip and palate (CLP) patients with severe maxillary hypoplasia. We introduce maxillary distraction osteogenesis for CLP patients with skeletal anchorage adapted on a stereolithographic model. PATIENTS: Six maxillary deficiency CLP patients treated according to our CLP treatment protocol had undergone maxillary distraction osteogenesis. METHOD: In all patients, computed tomography (CT) images were recorded preoperatively, and the data were transferred to a workstation. Three-dimensional skeletal structures were reconstructed with CT data sets, and a stereolithographic model was produced. On the stereolithographic model, miniplates were adapted to the surface of maxilla beside aperture piriforms. The operation performed involved a high Le Fort I osteotomy with pterygomaxillary disjunction. Miniplates were fixed to the maxillary segment with three or four screws and used for anchorage of the RED system. Retraction of the maxillary segment was initiated after 1 week. RESULTS: The accuracy of the stereolithographic models was enough to adapt the miniplates so that there was no need to readjust the plates during surgery. Postoperative cephalometric analysis showed that the direction of the retraction was almost parallel to the palatal plane, and dental compensation did not occur. CONCLUSIONS: We performed maxillary distraction osteogenesis with skeletal anchorage adapted on the stereolithographic models. Excellent esthetic outcome and skeletal advancement were achieved without dentoalveolar compensations.

Reproducibility of maxillary positioning in Le Fort I osteotomy: a 3-dimensional evaluation.

PURPOSE: In the present study, we evaluated the difference between the model surgery movement and the actual surgical movement in the horizontal (X), vertical (Y), and transverse (Z) directions using the same reference coordinates. PATIENTS AND METHODS: Twelve patients (6 male and 6 female, mean age of 24.3 years) who underwent Le Fort I osteotomy and sagittal split ramus osteotomy were included in the study. The maxillary position was controlled by an intermediate splint and face-bow/bite-fork combination system. A coordinate transformation system with transition matrices was developed, which enabled objective comparison between the planned surgical change of the maxilla on the articulator and the actual surgical change assessed by the 3-dimensional cephalogram. RESULTS: The absolute mean difference was 2.2 mm. The difference between the model surgery and the surgical result ranged from -7.7 mm to 6.6 mm. The surgical result differed from the planned surgical movement by more than 2 mm in more than 45% of the measured coordinate values. CONCLUSION: Although all of the patients were satisfied with their postsurgical appearance and occlusion, the result shows that further development is required in the maxillary positioning system.

Surgical results of primary lip repair using the triangular flap method for the treatment of complete unilateral cleft lip and palate: a three-dimensional study in infants to four-year-old children.

OBJECTIVE: To evaluate morphological problems for children with complete unilateral cleft lip and palate (UCLP). DESIGN AND SETTING: A cross-sectional study was performed on 46 patients with complete UCLP at Osaka University Dental Hospital. PATIENTS AND PARTICIPANTS: The method was applied to three groups of children with UCLP (8 4-month-old infants, 18 1.5-year-old children, and 20 4-year-old children). MAIN OUTCOME MEASURES: The three-dimensional coordinates of facial landmarks were extracted automatically from XYZ data sets and from photo images produced by an optical surface scanner. RESULTS: The intercanthal distance, nose width, and mouth width were closer to those of normal children in the older group. Deviation of the columella toward the noncleft side was smaller in the 4-year-old group. The angle of the nasal tip was large in all groups. Asymmetry of the ala was conspicuous at the upper part of the nose in the vertical dimension. Asymmetry of the nostril was observed in the vertical dimension and in the anteroposterior dimension in the 4-year-old group. The angle of the Cupid's bow was obtuse on the noncleft side, and the bottom of the Cupid's bow deviated toward the cleft side. The Cupid's bow was longer on the noncleft side. Protrusion of the vermilion was poor in all groups.

Three-dimensional analysis of facial morphology in normal Japanese children as control data for cleft surgery.

OBJECTIVE: This study presents an analysis of three-dimensional facial forms of normal Japanese children. DESIGN AND SETTING: Cross-sectional data (n = 247) were available from the Ikeda Public Health Center. PATIENTS AND PARTICIPANTS: Three groups of children (ninety-seven 4-month-old infants, fifty-four 1.5-year-old children, and eighty 3.5-year-old children) were analyzed using a three-dimensional anthropometric technique. MAIN OUTCOME MEASURES: Three-dimensional coordinates of facial landmarks were extracted automatically from XYZ data sets and photo images of an optical surface scanner. RESULTS: Only minor gender differences were noted. Lip height was not correlated with other facial dimensions. There was a significant correlation between upper face, nose, and mouth widths. Compared with adults, the upper face width was larger (approximately 70% to 80% of adults) than the middle and lower parts of the face. Width ratios were greater than height and depth ratios. The lip height ratio, however, was larger than the lip width ratio, and the angle of the cupid's bow was more acute in children. The angle of the nose was more obtuse, particularly in the axial plane. CONCLUSIONS: In cleft lip surgery involving young children, there may be no need to consider gender differences. Some characteristic differences exist between children and adults, however, and normal standards for children would be helpful in plastic surgery.