Surgical Correction Of Skeletal Class Research Articles

Orthognathic surgery improves compromised natural head position and pharyngeal airway in patients with Skeletal Class II or III malocclusion.

Natural head position (NHP), pharyngeal airway and maxillofacial growth pattern are correlated. The author's previous studies proved that following surgical correction of Skeletal Class II malocclusion, the over-extended NHP returned upright, and the pharyngeal airway space (PAS) dimension expanded. The present study compares the post-operative change in NHP and PAS after orthognathic surgery in Skeletal Class II and III malocclusion patients. Patients receiving orthognathic procedures to correct Skeletal Class II or III malocclusions were reviewed in this retrospective study. Pre-operative and 6-week post-operative cone-beam computed tomography datasets were collected. Variables representing the craniofacial pattern, the NHP and the PAS were measured three-dimensionally. Post-operative variables were compared with their pre-operative counterparts using either repeat-measure 2-way analysis of variance or Wilcoxon matched-pairs signed rank test. Thirty cases of Skeletal Class II malocclusion and 13 cases of Skeletal Class III malocclusion were collected. Preoperatively, the inter-group differences were significant in craniofacial pattern (68.14 ± 3.552 degree vs. 79.63 ± 2.497 degree, p < .0001) and the NHP (68.77 ± 11.02 degree vs. 82.83 ± 7.738 degree, p = .0002) while not significant in PAS; after surgery, the intergroup differences in craniofacial pattern and the NHP between groups decreased, and the PAS increased in both groups. Orthognathic surgery may improve compromised NHP and increase PAS in Skeletal Class II and III malocclusion patients.

Do Surgical Intervention Type and Baseline Condylar Position Affect Spatial Dimension Changes of the Temporomandibular Joint in the Surgical Correction of Skeletal Class II Deformities?

One of the key features of orthognathic surgery is altering temporomandibular joint (TMJ) condylar positions. This multivariate study aimed to identify surgical interventions and patient factors significantly associated with changes in TMJ spatial dimensions after the surgical correction of skeletal Class II deformities. This is a retrospective cohort study including patients who had undergone an isolated bilateral sagittal split ramus osteotomy (BSSO) or a bimaxillary osteotomy (BMO) for mandibular advancement and a control sample of patients treated with the removal of odontogenic cysts in the mandibular posterior region. Excluded were those who presented with specific radiographic signs of TMJ osteoarthrosis, severe facial asymmetry, or deformity secondary to trauma. The primary predictors were condylar position at baseline (anterior, concentric, and posterior), time points (T0, preoperatively; T1, immediately after surgery; and T2, 1-year follow-up), and surgical intervention type (BSSO, BMO, and control group). The primary outcomes were changes in posterior spatial dimension (PSD), superior spatial dimension, and medial spatial dimension assessed by cone-beam computed tomography preoperatively, immediately after surgery, and at 1-year follow-up. Covariates included sex, age, and amount of mandibular advancement. Estimations of independent effects of primary predictors on outcome variables were made by applying generalized estimation equation models. The value of statistical significance was P<.05. The study sample included 88 participants. The BSSO samples included 39 patients, and the BMO group included 22 patients; the control group comprised 27 subjects. The average age was 31.2years; the majority were female (61.4%). Adjusted generalized estimation equation models yielded a significant time interaction between BSSO and spatial dimensions over time (PSD, P<.001). Key predictors of spatial dimension changes were the baseline posterior (PSD, P<.001) and the central condylar position (PSD, P<.001). This controlled study, for the first time, provides scientific evidence on the effects of surgical intervention type and baseline condylar position on spatial dimension changes in the TMJ. It shows a more favorable outcome in long-term spatial dimension changes for patients treated by a BMO procedure.

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

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. 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), 1week after surgery (T1), and debond (T2). Intergroup comparison was conducted with independent t test. Correlations between the variables were estimated by Pearson correlation. The study sample was composed of 60 subjects with 30 subjects in each study group. In the Sgroup, 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 (<1mm), 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±1.40mm) than S group (0.04±1.32mm) by 0.77mm(P=.014). Greater surgical changes in the proximal segments had minor clinical effect on transverse stability. Minor transverse overcorrection of 1mm is recommended in cases with severe facial symmetry with extensive changes in the proximal segments.

Relapse patterns of two-jaw surgical correction in patients with skeletal Class III malocclusion and different vertical facial types

The aim of this study was to evaluate postoperative relapse after the surgical correction of skeletal Class III deformities of various facial patterns as a guide to surgical planning. A retrospective cohort study of 90 consecutive patients with skeletal Class III malocclusion who underwent bimaxillary surgery was performed. The surgical outcomes and postoperative stability were compared. The primary predictor variable was vertical facial type, which was classified into three groups according to the Frankfort mandibular plane angle (FMA). The primary outcome of angular and linear measurements was obtained using serial cone beam computed tomography scans obtained at time points of preoperative, 1 week after surgery, and orthodontic debonding. No significant difference in skeletal relapse was observed in patients with the different vertical facial types. The mandible displayed a forward and upward relapse in all three groups postoperatively. The patients with a low FMA exhibited a more consistent mandibular relapse pattern than those with a normal or high FMA. These findings suggest that bimaxillary surgery is clinically stable for mandibular prognathism regardless of the vertical facial pattern. However, 1–1.5 mm of overcorrection in the mandible setback should be considered in patients with a low FMA, because of the greater facial depth and consistent forward and upward mandibular relapse pattern.

Evaluation of facial aesthetics by laypersons in patients undergoing intraoral quadrangular Le Fort II osteotomy compared with conventional Le Fort I osteotomy

In this study we compared the aesthetic outcome of (1) Le Fort I (LFI) osteotomy and (2) intraoral quadrangular Le Fort II (IQLFII) osteotomy for surgical correction of skeletal class III dysgnathia involving midfacial deficiency. The aim was to investigate whether laypersons see differences in facial changes that occur due to variations of the osteotomy cuts. The patient collectives consisted of 23 patients in each group. Pre- and postoperative photographs were presented in a random sequence to 40 layperson raters. The rating procedure was conducted with a four-point Likert scale. Assessed characteristics were ‘attractiveness’ (‘Attraktivität’), ‘likeability’ (‘Sympathie’), ‘intelligence’ (‘Intelligenz’), ‘aggressiveness’ (‘Aggressivität’) and ‘dominance’ (‘Dominanz’). For preoperative photographs we found a significant difference for ‘likeability’ with lower ratings for the IQLFII group; all other criteria were rated similarly. For the IQLFII group we found a significantly larger shift from lower to higher ratings for ‘attractiveness’ and ‘likeability’ and a significantly larger shift from higher to lower ratings for ‘aggressiveness’ and ‘dominance’ than for the LF I group. Our study shows that lay raters detect significant differences between the two surgical groups. Thus, IQLFII osteotomy, when indicated, represents a favourable alternative to conventional LFI osteotomy, if patients desire the expectable change in recognition by their social circle.

Case report on the surgical correction of skeletal Class III by maxillary advancement

Class III malocclusion is exhibited either due to excessive mandibular growth, deficient maxillary growth, or both. Neither growth modification nor camouflage offers a solution for patients with severe Class III malocclusion. Surgery to realign the jaws or reposition dentoalveolar segments is the possible and stable treatment option. A combination of orthodontic and orthognathic phases offers remarkable results along with enhanced psychosocial acceptance. In this case report, Lefort I osteotomy was performed with maxillary inferior repositioning and advancement in a 25-year-old patient with skeletal Class III.

Trends in surgical-orthodontic management of Class III malocclusions in Western Australia

Abstract Aim The aim of this retrospective cohort study was to identify trends in the surgical-orthodontic management of skeletal Class III malocclusions in Western Australia between 1985 and 2016. Methods The records of 225 patients (132 females, 93 males) who received combined surgical-orthodontic correction of their Class III malocclusion between 1985 and 2016 were retrospectively assessed. The subjects were divided into three groups according to surgery type: Group (1) maxillary advancement only; Group (2) mandibular setback only; Group (3) two-jaw surgery. Results A trend towards two-jaw surgery for Class III correction was observed. Between 1985 and 2016, 123 patients (55%) were treated via two-jaw surgery; 97 patients (43%) were treated via maxillary advancement alone and five patients (2%) were treated via mandibular setback alone. Between 2011 and 2016, 61% were treated via two-jaw surgery; 37% were treated via maxillary advancement surgery; 2% were treated via mandibular setback surgery. Gender affected surgery type: two-jaw surgery (60% female); maxillary advancement (62% female); mandibular setback (17% female). A greater proportion of females received Class III surgical management in comparison with males (59:41). Conclusion Two-jaw surgery is the most common procedure for the surgical correction of skeletal Class III malocclusions in Western Australia. Of the single jaw procedures, isolated maxillary advancement surgery is more common than mandibular setback procedures.

Simultaneous Surgical Correction of Skeletal Class III Dentofacial Deformity During Acute Management of Facial Fractures: Patient Selection and Surgical Technique.

Mandibular prognathism is a common dentofacial deformity in Asia. Treatment of such condition may vary from orthodontic camouflage to surgical orthodontics with orthognathic surgery depending on the severity of the condition. Because of the prominent position of the mandible, fractures involving different locations of the mandible commonly occur in maxillofacial trauma. Anatomical reduction of maxillofacial fractures and restoration of the pretraumatic occlusion are the primary goals of acute management of facial fractures. In patients with dentofacial deformity, simultaneous surgical correction of their malocclusion and improvement of their facial aesthetics while providing open treatment to the maxillofacial fractures are rarely reported in the literature. We reported 3 cases with combined open reduction and internal fixation and surgery-first orthognathic surgery principles to correct class III malocclusion with mandibular prognathism during acute management of maxillofacial fractures. Computer-assisted surgical simulation was used in surgical planning and fabrication of surgical splint. Two patients underwent mandibular osteotomies in addition to open reduction and internal fixation of maxillofacial fractures. One patient had both maxillary and mandibular osteotomies during facial fracture repair. Class I occlusion with satisfactory facial profile was achieved in all 3 cases. Careful patient selection with presurgical planning using computer-assisted surgical simulation is essential in achieving successful outcomes in correcting dentofacial deformities while managing maxillofacial fractures. This combined technique is a viable option in the surgical management of facial fractures in patients with dentofacial deformities.

Does two-dimensional vs. three-dimensional surgical simulation produce better surgical outcomes among patients with class III facial asymmetry?

The aim of this study was to compare the outcomes of traditional two-dimensional planning (2DP) and three-dimensional surgical simulation (3DS) in the surgical correction of skeletal class III with facial asymmetry. This retrospective cohort study included 37 consecutive adult Taiwanese patients. Preoperative and postoperative three-dimensional cephalometric measurements were obtained from cone beam computed tomography scans. The outcome variables were the differences in preoperative and postoperative linear and angular measurements and the differences between the two groups after surgery. When the surgical result was compared between the 2DP and 3DS groups, significant differences were found for four cephalometric variables: the distance from gonion on the non-deviated side to the midsagittal plane (MSP), mid-gonion to the MSP, upper first molar on the non-deviated side to the Frankfort horizontal plane, and the yaw angle. In the 3DS group, mandibular symmetry was achieved because the centre between the bilateral gonions was improved, and because there was no significant difference in the horizontal gonion (Go to the MSP) between the deviated and non-deviated sides after surgery. 3DS provides all the necessary information for planned surgical movements for the correction of facial asymmetry; it should be considered during surgical planning to improve surgical outcomes, particularly the achievement of bilateral mandibular contour symmetry.

The effect of early physiotherapy on the recovery of mandibular function after orthognathic surgery for class III correction. Part II: Electromyographic activity of masticatory muscles

The study was conducted to evaluate the effect of early physical rehabilitation by comparing the differences of surface electromyographic (sEMG) activity in the masseter and anterior temporalis muscles after surgical correction of skeletal class III malocclusion. The prospective study included 63 patients; the experimental groups contained 31 patients who received early systematic physical rehabilitation; the control group (32 patients) did not receive physiotherapy. The amplitude of sEMG in the masticatory muscles reached 72.6–121.3% and 37.5–64.6% of pre-surgical values in the experimental and control groups respectively at 6 weeks after orthognathic surgery (OGS). At 6 months after OGS, the sEMG reached 135.1–233.4% and 89.6–122.5% of pre-surgical values in the experimental and control groups respectively. Most variables in the sEMG examination indicated that recovery of the masticatory muscles in the experimental group was better than the control group as estimated in the early phase (T1 to T2) and the total phase (T1 to T3); there were no significant differences between the mean recovery percentages in the later phase (T2 to T3). Early physical rehabilitative therapy is helpful for early recovery of muscle activity in masticatory muscles after OGS. After termination of physical therapy, no significant difference in recovery was indicated in patients with or without early physiotherapy.

Three-Dimensional Analysis of Soft Tissue Changes in Full-Face View After Surgical Correction of Skeletal Class III Malocclusion

The objective of this study was to evaluate changes in soft tissue in full-face view because of surgical correction of skeletal Class III malocclusion, using 3-dimensional (3D) laser scanning. Twenty-seven subjects with skeletal Class III malocclusion [11 males; mean age (SD), 24.0 (5.7) years] underwent bilateral sagittal split ramus osteotomy for mandibular setback combined with Lefort I osteotomy with/without maxillary advancement. Twelve patients (group 1) had mandibular setback surgery, and the other 15 (group 2) had combination surgery. Lateral cephalograms and 3D facial scan images were assessed preoperatively and postoperatively. The facial widths upon superimposition of 3D facial images were measured in the same coordinates using a Rapidform 2006 system. Paired and independent t tests were done for statistical analysis. The midface soft tissue broadened significantly above the cheilion plane postoperatively (P < 0.05). A larger change was observed nearer to subnasale plane, and a similar trend was seen among the horizontal planes in 1- or 2-jaw surgery groups. The widths from the exocanthion plane to the subnasale plane increased more in group 2 [mean (SD), 4.45 (2.45) mm, 8.71 (2.92) mm, and 7.62 (3.13) mm] than those in group 1 [mean (SD), 1.26 (0.97) mm, 1.84 (1.06) mm, and 1.35 (0.65) mm], and this difference was significant (P < 0.05). There was a decrease below the cheilion plane with mandibular setback between groups, but this difference was not significant. The measurement method used here for the shape outline of the lateral parts of the face could provide quantitative data for the clinical evaluation and objective analysis of the human face in full-face view. The midface soft tissue in subjects with skeletal Class III malocclusion exhibited a greater increase in width after bimaxillary surgery procedures than mandibular setback-only surgery.

Clinical evaluation of temporomandibular joint disorder after orthognathic surgery in skeletal class II malocclusion patients

Objectives: This study was performed in order to evaluate the occurrence of temporomandibular joint disorder after surgical correction of skeletal class II malocclusion. Materials and Methods: This study included 21 patients who underwent orthognathic surgery for the correction of dentofacial deformities by a single surgeon at Mokdong Hospital, Ewha Womans University from 2000 to 2010. They underwent bilateral sagittal split ramus osteotomy for the treatment of undesirable mandibular advancement. The emporomandibular disorder (TMD) symptoms prior to surgery were recorded and the radiographic evaluation (panorama, bone scan, and magnetic resonance imaging [MRI]) of the post-surgery temporomandibular joint (TMJ) were assessed in order to evaluate condylar resorption, remodeling and disc displacement. The minimum follow-up period, including orthodontic treatment, was 12 months. Orthognathic procedures included 1-jaw surgery (n=8 patients) and 2-jaw surgery (n=13 patients). The monocortical plate was used for bilateral sagittal split ramus osteotomy fixation. Results: Among class II malocclusion patients with TMD symptom, clicking improved in 29.1%, and maximum mouth opening increased from 34.5±2.1 mm to 37.2±3.5 mm. The differences were not statistically significant, however. Radiographic changes in bone scan improved slightly based on the report by radiologist but not in TMJ dynamic MRI. Conclusion: No particular improvements were found in patients with joint sound only. Patients with limitation of mouth opening showed an increase in the degree of opening, but the difference was not statistically significant (P >0.05).

Stability Factors After Double-Jaw Surgery in Class III Malocclusion

To identify the stability factors of skeletal Class III malocclusion after double-jaw surgery by a systematic review of the literature. The survey covered the period from September 1959 to October 2007 and used the MeSH, Medical Subject Headings. The inclusion criteria were stability of bimaxillary surgery of the permanent dentition, adult patients with skeletal Class III malocclusion, a follow-up of at least 12 months, randomized and nonrandomized controlled clinical trials (RCCTs; CCTs), prospective and retrospective studies with and without concurrent untreated as well as normal controls, and clinical trials (CTs) comparing at least two treatment strategies without any untreated or normal control group. The search strategy resulted in 1783 articles. After selection according to the inclusion/ exclusion criteria, 15 articles qualified for the final review analysis. Quality was low in two studies, medium in twelve, and medium/high in one article, which was represented by a RCT (randomized clinical trial). Most of the studies had sufficient sample size, method error analysis, and adequate statistical methods. Thus, the quality level of the studies was sufficient to draw evidence-based conclusions. Surgical correction of skeletal Class III malocclusion after combined maxillary and mandibular procedures appears to be stable for maxillary advancements up to 5 mm and for the correction of presurgical sagittal intermaxillary discrepancies smaller than 7 mm.

Nasal Changes after Surgical Correction of Skeletal Class III Malocclusion in Koreans

To quantify the changes in the nose after bimaxillary surgery to correct skeletal Class III malocclusion and to test the hypothesis that there is no change in the nasal width following bimaxillary surgical correction of skeletal Class III when a nasal cinch is properly used. Sixty-five adult Korean skeletal Class III patients who had received maxillary advancement/impaction and mandibular set-back surgery in conjunction with an alar base cinch suture were evaluated. The anthropometric variables of the nasal region were measured directly on the soft-tissue surface before and 6 months after surgery. After surgery, the alar width and alar base width had increased significantly (P < .001), while the nasal tip projection decreased (P < .001). The nostril morphology also showed widening (P < .001). There was a trend for females with a narrow alar width presurgically to have a larger amount of nasal widening compared with those with a broader alar width (P < .05). There is a high probability of nasal and nostril widening after bimaxillary surgery for skeletal Class III malocclusion in Koreans despite the careful performance of alar cinch suture. Nevertheless, the authors believe that alar cinch suture was positive in limiting the nasal widening to the minimum and would consider routine application during bimaxillary surgery for skeletal Class III especially for female patients with a narrow nose who are susceptible to these changes.

Patient satisfaction following orthognathic surgical correction of skeletal Class III malocclusion

Patient satisfaction following orthognathic surgical correction of skeletal Class III malocclusion

骨格性下顎前突症患者の外科的矯正治療前後における下顎運動の分析

After surgical correction of skeletal class III malocclusions, their morphological and functional changes are observed. The functional changes of mandibular movements were analyzed from a threedimensional standpoint in this study.In regard to protrusion and lateral excursions, the range of motion of incisal and condylar points between intercuspal position and each occlusal border position was measured. In regard to maximum opening movement, amount of opening at incisal points and the range of motion of the condylar points was measured.The results were as follows1. The range of motion between intercuspal position and each occlusal border position increased after surgery for both incisal and condylar points. This is due to the stylomandibular ligament restricting each occlusal border position which moves backward by sagittal splitting osteotomy and to the correction of occlusal interferance during protrusion before surgery.2. The amount of maximum opening in maximum opening movement showed little change, but the range of motion of the condylar path showed an increasing tendency after surgery. It is suggested that there is close relationship between the change of the range of motion of condylar points and the morphological change of the ramus.

Midface asymmetry

In this study we compared the aesthetic outcome of (1) Le Fort I (LFI) osteotomy and (2) intraoral quadrangular Le Fort II (IQLFII) osteotomy for surgical correction of skeletal class III dysgnathia involving midfacial deficiency. The aim was to investigate whether laypersons see differences in facial changes that occur due to variations of the osteotomy cuts. The patient collectives consisted of 23 patients in each group. Pre- and postoperative photographs were presented in a random sequence to 40 layperson raters. The rating procedure was conducted with a four-point Likert scale. Assessed characteristics were ‘attractiveness’ (‘Attraktivität’), ‘likeability’ (‘Sympathie’), ‘intelligence’ (‘Intelligenz’), ‘aggressiveness’ (‘Aggressivität’) and ‘dominance’ (‘Dominanz’). For preoperative photographs we found a significant difference for ‘likeability’ with lower ratings for the IQLFII group; all other criteria were rated similarly. For the IQLFII group we found a significantly larger shift from lower to higher ratings for ‘attractiveness’ and ‘likeability’ and a significantly larger shift from higher to lower ratings for ‘aggressiveness’ and ‘dominance’ than for the LF I group. Our study shows that lay raters detect significant differences between the two surgical groups. Thus, IQLFII osteotomy, when indicated, represents a favourable alternative to conventional LFI osteotomy, if patients desire the expectable change in recognition by their social circle.