Does Clockwise Rotation of Maxillomandibular Complex Using Surgery-First Approach to Correct Mandibular Prognathism Improve Facial Appearance?

BACKGROUND: Facial aesthetics may be optimized based on a deeper understanding of soft tissue changes after orthognathic surgery. PURPOSE: The purpose of the study was to delineate facial soft tissue changes after clockwise rotation (CWR) of the maxillomandibular complex (MMC) to correct mandibular prognathism using the surgery-first approach. STUDY DESIGN, SETTING, SAMPLE: This prospective cohort study enrolled patients over 18 years of age with skeletal Class III malocclusion in the craniofacial center. The patients were excluded with previous history of craniofacial syndrome, orthognathic surgery trauma, infection at surgical sites, chin deviation (menton deviation ≥4 mm), 2 or more missing data points after surgery, or without informed consent. This study compared significant facial changes before (T0) and after orthodontic debonding (T1) in the CWR and control groups. PREDICTOR VARIABLE: The patients were divided in accordance with maxillary occlusal plane change (OPC) after surgery into CWR (OPC >4°) and control (OPC ≤4°) groups. MAIN OUTCOME VARIABLE: The primary outcome variable was frontal lip curvature (FLC: Right Cheilion-Stomion-Left Cheilion, degree) with or without upper lip curving upward at T1, where upper lip curving upward was considered more favorable. COVARIATES: The covariates included age, sex, and various cephalometric measurements. ANALYSES: The Mann-Whitney U test, paired, and independent t-test were implemented to compare the intragroup and intergroup differences. Statistical significance was indicated by P value <.05. RESULTS: The study comprised 34 patients (21 women) in the control group and 37 (29 women) in the CWR group; their mean ages were 23.64 ± 4.38 and 24.21 ± 3.84 years, respectively (P value = .562). At T1, the CWR group had significant increased FLC (P value = .001), alar width (P value = .034), and lower vermilion height (P value = .018), and decreased lower lip length (P value = .004). The high FLC group had significant decreased upper lip projection (P value = .002) and increased nasolabial angle (P value = .013). The significant relationship between CWR and high FLC was supported by the χ2 test (P value = .018) and multiple logistic regression (P value = .017). CONCLUSION: Greater CWR of the MMC increased FLC and lower vermilion height and reduced lower lip length. High FLC resulting from the CWR of the MMC improved facial appearance by moving the upper lip curve upward.

Surgical Stability After Proximal Segment Angle Alteration in Patients With Class III Facial Asymmetry.

PURPOSE: Patients with facial asymmetry often seek improved symmetry in lower face contour resulting in transverse movement of the proximal segments. The study aimed to investigate the association between transverse change in the proximal segments and postoperative relapse after the surgical correction of skeletal Class III facial asymmetry. METHODS: This retrospective cohort study includes consecutive patients with skeletal Class III asymmetry who underwent 2-jaw orthognathic surgery. The primary predictor variable was ramus plane angle (RPA). The patients were grouped as small (S group, <4°) and large (L group, ≥4°) changes in RPA. The primary outcome was the positional change of B point, menton, and the intergonial width. Cone-beam computed tomography images were obtained before surgery (T0), 1 week after surgery (T1), and debond (T2). Intergroup comparison was conducted with independent t test. Correlations between the variables were estimated by Pearson correlation. RESULTS: The study sample was composed of 60 subjects with 30 subjects in each study group. In the S group, the mean surgical changes of RPA were inward rotated 0.91° bilaterally. In the L group, the mean surgical changes of RPA were inward rotated 4.80° and 0.32° on the deviated and non-deviated side. After surgery, further minor inward adaptation of both sides was noted (<1 mm), and intergonial distance reduced with these changes in the proximal segments. By comparing the postsurgical stability between S and L group, the overall sagittal and vertical stability had no significant difference between 2 groups. However, the postsurgical transverse menton relapse (ΔMe in T2-T1) was significantly larger in L group (0.81 ± 1.40 mm) than S group (0.04 ± 1.32 mm) by 0.77 mm (P = .014). CONCLUSION: Greater surgical changes in the proximal segments had minor clinical effect on transverse stability. Minor transverse overcorrection of 1 mm is recommended in cases with severe facial symmetry with extensive changes in the proximal segments.

Sequential digital occlusal analysis in patients with skeletal Class III malocclusion with orthognathic surgery: Surgery-first vs orthodontic-first approach.

INTRODUCTION: This study compared changes in occlusal characteristics in patients with skeletal Class III malocclusion with surgery-first approach (SFA) and those with orthodontic-first approach (OFA) through digital occlusal analysis. METHODS: In this prospective study, 90 consecutive subjects were divided into control, OFA, and SFA groups (30 per group). Force discrepancy, occlusal time, tooth contact, center of force, and force-time graph pattern were calculated for all samples using the T-Scan III system. Between-group differences were analyzed using a 1-way analysis of variance and generalized estimating equations. These parameters were calculated at the following time points: preoperatively, 1-month postoperatively (T1), 4-months postoperatively, and 1-year postoperatively (T3). RESULTS: No significant differences were observed in the parameters between the experimental groups. The force discrepancy of the OFA and SFA groups decreased, approaching the value of controls at T3. The occlusal time significantly increased at T1 and progressively decreased at T3. The initial contact and maximum force were most frequently observed on molars, and its maximum force significantly decreased by 5.72% and 7.40% in the OFA and SFA groups at T3, respectively. The number of tooth contact was significantly reduced at T1 and gradually increased at T3. Moreover, after surgery, the force-time graph pattern was normalized, and the center of force tended to be more centric; however, the most frequent trajectory revealed premature contact during closing. CONCLUSIONS: No significant difference was found in all parameters between the OFA and SFA groups. Occlusion deteriorated at 1 month postoperatively but gradually improved at 1 year postoperatively, approaching the controls.

Effects of maxillary advancement on maxillary incisor display in patients with skeletal Class III malocclusion and cleft lip and palate.

INTRODUCTION: The information on the hard- and soft-tissue factors correlated with tooth display after LeFort I osteotomy, especially in the surgery-first approach (SFA), are limited. This study aimed to correlate different parameters with the maxillary incisor display in patients with skeletal Class III malocclusion and those with cleft lip and palate (CLP) in SFA. METHODS: This study consisted of 35 patients with skeletal Class III malocclusion and 32 with cleft deformities who had undergone orthognathic surgery. Pretreatment and posttreatment lateral cephalometric analysis were obtained. Maxillary incisor display was measured in photographs. The intraclass correlation coefficient was used to assess the intraexaminer repeatability. The Student t test was used to compare the maxillary incisor display between 2 groups. Analysis of covariance was performed with pretreatment measurement as covariates, and the important determinants for maxillary incisor display were identified by adjusting the baseline measurements. RESULTS: The mean increase of maxillary advancement at point A was 5.25 mm and 1.28 mm downward movement for skeletal Class III malocclusion, whereas it was 4.59 mm advancement and 2.16 mm downward movement for patients with CLP. The resulting maxillary incisor display was 2.86 mm for skeletal Class III malocclusion and 2.56 mm for patients with CLP. The covariates for maxillary incisor display before intervention was significantly associated with the maxillary incisor display after intervention (P <0.001). However, the interaction effect of groups was not seen (P = 0.933). The horizontal position of A, vertical position of ANS, and upper lip length were the most predictable parameters (P <0.001, P <0.001, P = 0.048, respectively) for maxillary incisor display in both groups. CONCLUSIONS: Horizontal position of point A, vertical position of ANS, and upper lip length are the most important determinants for maxillary incisor display for patients with skeletal Class III malocclusion and those with CLP.

Does Sleep Quality Affect Temporomandibular Joint With Degenerative Joint Changes?

PURPOSE: The purpose of this study was to answer the following question: Among female patients who have skeletal Class III malocclusion, does poor sleep quality increase the prevalence of degenerative joint changes in the temporomandibular joints (DJC-TMJ)? MATERIALS AND METHODS: We designed a prospective cohort study and enrolled female patients who required orthognathic surgery to correct skeletal Class III malocclusion from January 2014 to December 2017. This is the first serial study to identify the relationship between sleep quality and DJC-TMJ before orthognathic surgery. The predictor variable was sleep quality, documented either as poor, indicated by a Pittsburgh Sleep Quality Index (PSQI) score of 5 or greater, or as good, indicated by a PSQI score of less than 5. The primary outcome variable was the presence of 5 or more DJC-TMJ signs or fewer than 5 DJC-TMJ signs. Other associated variables were grouped into the following categories: demographic variables (age and body mass index) and cephalometric data. Descriptive bivariate statistics were computed and univariate and multiple logistic regression analyses were conducted to identify factors associated with DJC-TMJ. RESULTS: The sample was composed of 52 patients grouped as follows: good sleep quality group (n = 25, PSQI score < 5) and poor sleep quality group (n = 27, PSQI score ≥ 5). Poor sleep quality was significantly associated (P = .027) with an increase in DJC-TMJ signs. In the multiple regression model, a PSQI score of 5 or greater (adjusted odds ratio, 5.806; 95% confidence interval, 1.406 to 23.974) and greater sella-nasion-point A angle (adjusted odds ratio, 1.453; 95% confidence interval, 1.127 to 1.871) were significantly associated (P < .05) with an increased prevalence of DJC-TMJ. CONCLUSIONS: The results of this study suggest that in female patients with skeletal Class III malocclusion, poor sleep quality could increase the prevalence of DJC-TMJ. Future cohort studies are required to support that sleep disturbance can increase DJC-TMJ in the general population.

Does Sensory Retraining Improve Subjective Rating of Sensory Impairment after Bilateral Sagittal Split Osteotomy?

BACKGROUND: Sensory retraining could ameliorate neurosensory disturbance (NSD) resulting from the injury of the inferior alveolar nerve after a bilateral sagittal split osteotomy (BSSO). The aim of this study was to measure the effects of sensory retraining on NSD. METHODS: A randomized, prospective, single-blinded clinical trial was conducted on consecutive patients with NSD resulting from a BSSO to correct skeletal class III malocclusion. The outcome measurement of sensory recovery was performed using a patient-centered survey assessed by the total score of questionnaire (TSQ) and visual analogue scale (VAS) at preoperation (T0), 1 week after surgery (T1), each month from 1 to 6 months after surgery (T2-T7), and 1 year after surgery (T8). RESULTS: In total, 115 consecutive patients were randomized into a control group (56 patients without sensory retraining) or study group (59 patients with sensory retraining). TSQ and VAS values continually decreased from T1 to T8 in both groups. The study group tended to have lower, but not significantly lower, TSQ and VAS values than the control group at each postoperative time point. Women and men responded similarly to sensory retraining at each time point. The oldest patients did not respond well to sensory retraining, compared with the youngest patients, from T1 to T8, and this age effect evaluated by the VAS reached a significant difference at T7 and T8. CONCLUSION: NSD, assessed by the TSQ and VAS, continually decreased over time after the BSSO. Sensory retraining could improve NSD, but not significantly.

Predicting need for orthognathic surgery in early permanent dentition patients with unilateral cleft lip and palate using receiver operating characteristic analysis.

INTRODUCTION: The purpose of this study was to predict the need for orthognathic surgery in patients with unilateral cleft lip and palate (UCLP) in the early permanent dentition. METHODS: In this retrospective cohort study, we included 61 patients with complete UCLP (36 male, 25 female; mean age, 18.47 years; range, 16.92-26.17 years). The subjects were grouped into an orthognathic surgery group and a nonsurgery group at the time of growth completion. Lateral cephalograms obtained at the age of 11 years were analyzed to compare the 2 groups. The receiver operating characteristic analysis was applied to predict the probability of the need for orthognathic surgery in early adulthood by using the measurements obtained at the age of 11 years. RESULTS: SNB, ANB, SN, overbite, overjet, maxillary length, mandibular body length, and L1-MP were found to be significantly different between the 2 groups. For a person with a score of 2 in the 3-variable-based criteria, the sensitivity and specificity for determining the need for surgical treatment were 90.0% and 83.9%, respectively (ANB, ≤-0.45°; overjet, ≤-2.00 mm; maxillary length, ≤47.25 mm). CONCLUSIONS: Three cephalometric variables, the minimum number of discriminators required to obtain the optimum discriminant effectiveness, predicted the future need for orthognathic surgery with an accuracy of 86.9% in patients with UCLP.

Three-dimensional surgical changes of mandibular proximal segments affect outcome of jaw motion analysis.

PURPOSE: Displacement of the mandibular proximal segments is inevitable in surgical correction of the asymmetric mandible. The aim of the present study was to assess the outcomes of jaw motion analysis (JMA) in relation to the changes in the mandibular proximal segments after orthognathic surgery (OGS). PATIENTS AND METHODS: The present retrospective cohort study investigated the surgical changes using the cone-beam computed tomography records and the mandibular function with JMA and a temporomandibular joint (TMJ) examination. The predictor variables were the 3-dimensional (3D) changes in the proximal segments on the deviated and nondeviated sides. The outcome variables were the JMA data obtained 6 months after OGS. The Pearson correlation test was performed to assess the relationship between the surgical changes and the outcome of JMA. RESULTS: Twenty-one adult patients with skeletal Class III malocclusion and mandibular deviation greater than 4 mm were included in the present study. The change of the ramus axis to the coronal plane on the deviated side correlated negatively with the laterotrusive movement of the mandible toward the deviated side (r = -0.452, P < .05). The changes in the distance from the condyles to the midsagittal plane and the angulation of the ramus axis to midsagittal plane on the nondeviated side correlated negatively with the condyle range of retrusion on both sides. However, the increase in the angulation of the ramus axis to the midsagittal plane on the nondeviated side correlated positively with the angle of the horizontal condylar movement in laterotrusion on the deviated side (r = 0.458, P < .05). CONCLUSIONS: 3D model visualization enabled us to clearly detect the changes in the proximal segments after OGS. A relationship between the condylar range of motion and skeletal changes in the proximal segments in patients with Class III malocclusion was observed, mainly on the deviated side of the mandible.

Longitudinal observation of mandibular motion pattern in patients with skeletal Class III malocclusion subsequent to orthognathic surgery.

PURPOSE: The aims of the present study were to delineate the characteristic patterns of 3-dimensional (3D) mandibular movement in patients with skeletal Class III malocclusion compared with normal individuals and to investigate the longitudinal changes in mandible and condylar motion after orthognathic surgery (OGS). PATIENTS AND METHODS: The subjects in the present prospective study consisted of 2 groups. The OGS group included 24 patients with skeletal Class III who underwent OGS. The control group consisted of 25 patients who underwent orthodontic treatment only. The patient records included demographic data, lateral and posteroanterior cephalometric radiographs before treatment, and serial mandibular motion data. In the OGS group, the mandibular motion data were obtained before OGS (T1), 1 month after OGS (T2), and at least 6 months after OGS (T3). The differences in cephalometric measurements and mandibular movements between the 2 groups were compared. The Pearson correlation test was performed to assess the relationship between the cephalometric measurements and the mandibular movements. Serial changes in mandibular movement in the OGS group were also compared. RESULTS: The skeletal pattern in the OGS group demonstrated retrusive maxilla and a protrusive mandible, with a larger mandibular plane angle. For the incisal range of motion, the OGS group's maximal mouth opening was larger than the control group's by 6.9 mm. In the OGS group, the condylar range of motion in retrusion and the Bennett angle were asymmetric. Skeletal Class III patients tended to have a smaller range of condylar retrusion. At 1 month after OGS, the maximal incisal range of motion decreased from 57.23 to 25.61 mm. Other variables, including laterotrusion, movement velocity, and angle and distance of condylar movement in protrusion, reduced significantly. The Bennett angle demonstrated increased symmetry on both sides. Six months after OGS, the condylar motion in opening demonstrated improvements, but to a lesser extent than at T1. The condylar motion in retrusion recovered totally. The maximum incisal range of motion reduced slightly, but remained similar in value to that of the control group. The variables, including laterotrusion, movement velocity, and angle and distance of condylar movement in protrusion, demonstrated total recovery. The mandibular movement variables at T3 were not significantly different from those of the control group. CONCLUSIONS: Skeletal Class III patients demonstrated a larger maximal mouth opening than did the controls, along with similar laterotrusion, but with a smaller retrusive condylar range of movement. The range of incisor motion and condylar movement did not correlate. The deterioration in mandibular motion after OGS can recover totally within 6 months. At T3, the mandibular movement remained consistent with the amount in normal subjects.

Orthognathic surgery considerations for patients with undiagnosed type I osteogenesis imperfecta.

PURPOSE: This study reports the senior author's experience of orthognathic surgery in patients with prognathism and undiagnosed type I osteogenesis imperfecta and includes a review of the literature. PATIENTS AND METHODS: Two patients with undiagnosed type I osteogenesis imperfecta underwent orthognathic surgery for correction of prognathism at Chang Gung Craniofacial Center, Taipei, Taiwan. The initial surgical plan was to perform 2-jaw orthognathic surgery in both patients. RESULTS: The bone quality was found to be fragile during the operation, and the original plan was changed intraoperatively to 1-jaw mandibular surgery. Both operations were performed without complications, and wound healing progressed normally. Both the final facial profile and occlusal outcome were satisfactory in 1 patient, with mild relapse occurring in the second patient. CONCLUSIONS: For patients with type I osteogenesis imperfecta, the orthognathic surgery plan should be simplified as much as possible. Prolonged intermaxillary fixation is recommended to facilitate bone union. Complications could possibly be avoided.

Surgical approach to the patient with bimaxillary protrusion.

The patient who has bimaxillary protrusion often is treated using a combination of orthodontics and orthognathic surgery, and the general approach is dental extraction with retraction of the incisors. In certain cases, maxillary excess may be corrected solely with LeFort I osteotomy and setback and without dental extraction or anterior segmental osteotomies. This article discusses (1) treatment evaluation and planning and (2) the specific surgical techniques, primarily anterior segmental osteotomies and the technical details for setback of the LeFort I osteotomized segment (more than 5 mm), as they relate to the surgical approach of the patient who has bimaxillary protrusion.