Ellen Wen-Ching Ko

Temporomandibular joint reconstruction in children using costochondral grafts

PURPOSEnThe aim of this study was to evaluate the postoperative growth of the mandible after reconstruction of the condylar process using costochondral grafts in children.nnnPATIENTS AND METHODSnTemporomandibular joint (TMJ) ankylosis was surgically treated and the joint reconstructed with a costochondral graft (CCG) in two boys and eight girls with a mean age of 7.4 years. Two children had bilateral ankylosis. Postoperative changes and craniofacial growth were monitored by lateral and posteroanterior (PA) cephalograms annually from 2 to 6 years (mean of 4 years).nnnRESULTSnPostoperatively, in the eight children with unilateral TMJ reconstruction, the mandible (Co-Gn) grew an average of 14.7 mm in length on the affected side and 15.1 mm on the nonaffected side; ramus length (Co-Go) increased an average of 7.1 mm on the affected side and 7.3 mm on the nonaffected side. However, in five of the children the chin progressively deviated toward the nonaffected side after TMJ reconstruction. The CCGs tended to have a more vertically directed condylar growth pattern and a more laterally positioned condyle. In the two cases with bilateral TMJ reconstruction, the CCGs grew until there was a mandibular prognathism that required orthognathic surgery to set back the mandible.nnnCONCLUSIONSnUsing CCGs to reconstruct TMJ ankylosis in children provides a functional condyle with growth potential. However, there is a possibility of excessive growth of the graft, resulting in deviation of the chin and mandibular prognathism years later.

Presurgical Orthodontics versus No Presurgical Orthodontics: Treatment Outcome of Surgical-orthodontic Correction for Skeletal Class Iii Open Bite

Background: It has long been claimed that presurgical orthodontics is crucial to the outcome of surgical-orthodontic treatment for dentofacial deformity. However, in the literature, the effect of presurgical orthodontics on the treatment outcome remains controversial. The purpose of the study was therefore to investigate the effect of presurgical orthodontics on the treatment outcome in terms of facial aesthetics, occlusion, stability, and efficiency. Methods: Thirty-three adult patients with skeletal class III open bite corrected by Le Fort I posterior impaction and bilateral sagittal split osteotomy were included. The patients were divided into two groups: 13 received presurgical orthodontics, and 20 did not. Cephalometric radiographs and study models were used to evaluate the treatment outcome. Results: There were no between-group differences in facial aesthetics, overbite, or Peer Assessment Rating score. Overjet was larger in the no–presurgical orthodontics group than in the presurgical orthodontics group, but both were within normal limits. Both groups had similar maxillary and horizontal mandibular stability. Although the vertical mandibular stability was worse in the no–presurgical orthodontics group than in the presurgical orthodontics group, the direction of instability was favorable for open bite correction. Finally, longer treatment time was required in the presurgical orthodontics group compared with the no–presurgical orthodontics group (512 ± 103 days versus 342 ± 127 days; p < 0.001). Conclusions: The results suggest that in surgical-orthodontic correction of skeletal class III open bite, presurgical orthodontics has no clinically significant effects on facial aesthetics, occlusion, or stability. However, presurgical orthodontics has a significant adverse effect on efficiency. Patients receiving presurgical orthodontics undergo longer treatment time than those receiving no presurgical orthodontics.

Palatal surface area measurement: comparisons among different cleft types.

The purpose of this study was to use three-dimensional imaging methods to measure the palatal surface of unrepaired cleft patients. The surface area of the palate was defined and measured on three-dimensional computed tomography images of dental plaster models in four different groups of cleft patients at 3 months of age. There were 30 unilateral complete cleft lips and palates (UCLP), 27 bilateral complete cleft lips and palates (BCLP), 23 isolated cleft palates of incomplete form (CP), and 19 unilateral cleft lips without cleft palates (UCL). These patients were nonsyndromic, unoperated, and without other major deformities. The dental casts were scanned, and the computed tomography data were transferred to an imaging laboratory for processing and reconstruction of three-dimensional images. Surface area of the palate was delineated, which was defined as within the alveolar crest and the line connecting both tuberosities. In UCLP and BCLP, the edge of cleft formed the medial boundary of the area for each palatal shelf, and the palatal surface area was the combination of both palatal shelves and the premaxillary area in BCLP group. The surface area was measured. Repeated definition and measurement tasks were performed for calculation of errors. The imaging data management and measurement were performed using the Analyze program (Biomedical Imaging Resource, Mayo Foundation, MN). In addition, linear distances were measured between the canine points on the alveolar crest (line C) and the tuberosity points (line T). The measurements were compared among the different groups. Analysis of variance and multiple comparisons were used for statistical analyses. The results showed that the mean error between repeated area definitions and measurements in this study was 1.86%. The bilateral complete cleft lip and palate (BCLP) and unilateral complete cleft lip and palate (UCLP) groups had significantly smaller palatal surface area than the unilateral cleft lip without cleft palate (UCL) and isolated cleft palate of incomplete form (CP) groups. There was no significant difference between the BCLP and UCLP groups. Line C and line T distances were significantly longer in BCLP and UCLP groups than in UCL and CP groups. The findings suggest that compared with UCL and CP patients, there is an intrinsic tissue deficiency in the palate/maxilla of BCLP and UCLP patients.

Comparison of Transverse Dimensional Changes in Surgical Skeletal Class III Patients With and Without Presurgical Orthodontics

PURPOSEnTo investigate transverse dimensional changes of dental arches in surgical skeletal Class III patients with and without presurgical orthodontics.nnnMATERIALS AND METHODSnThirty-six patients with skeletal Class III were included and grouped into those with or without presurgical orthodontics. Eighteen patients (mean age, 22.3 +/- 3.8 years) with presurgical orthodontics (mean presurgical orthodontic treatment time, 176.3 +/- 38.3 days) were in the orthodontics-first (OF) group; the other 18 patients (mean age, 23.3 +/- 4.2 years) without presurgical orthodontics were in the surgery-first (SF) group. The posteroanterior cephalograms initially, before surgery, immediately after surgery, and 1 year after surgery were traced and analyzed. The inclination change of canines and molars was measured to interpret the changes of transverse dimension in both dental arches. Paired and unpaired t tests were performed to test intra- and intergroup differences (P < .05).nnnRESULTSnDental changes in transverse planes demonstrated a similar trend in both groups. The maxillary canines were buccally tilted (SF vs OF group, 1.7 degrees vs 1.9 degrees), the maxillary molars were lingually tilted (SF group vs OF group, -4.7 degrees vs -1.0 degrees), the mandibular canines were lingually tilted (SF group vs OF group, 2.9 degrees vs 2.8 degrees), and the mandibular molars were buccally tilted (SF group vs OF group, -6.1 degrees vs -5.4 degrees).nnnCONCLUSIONnThe magnitude and trend of transverse dental changes in patients with surgical skeletal Class III were similar whether receiving presurgical orthodontics or not.

The stability of mandibular prognathism corrected by bilateral sagittal split osteotomies: a comparison of bi-cortical osteosynthesis and mono-cortical osteosynthesis

This study evaluated the differences in surgical changes and post-surgical changes between bi-cortical and mono-cortical osteosynthesis (MCO) in the correction of skeletal Class III malocclusion with bilateral sagittal split osteotomies (BSSOs). Twenty-five patients had bi-cortical osteosynthesis (BCO), 32 patients had mono-cortical fixation. Lateral and postero-anterior cephalometric radiographs, taken at the time of surgery, before surgery, 1 month after surgery, and on completion of orthodontic treatment (mean 9.9 months after surgery), were obtained for evaluation. Cephalometric analysis and superimposition were used to investigate the surgical and post-surgical changes. Independent t-test was performed to compare the difference between the two groups. Pearsons correlations were tested to evaluate the factors related to the relapse of the mandible. The sagittal relapse rate was 20% in the bi-cortical and 25% in the mono-cortical group. The forward-upward rotation of the mandible in the post-surgical period contributed most of the sagittal relapse. There were no statistically significant differences in sagittal and vertical changes between the two groups during surgery and in the post-surgical period. No factors were found to correlate with post-surgical relapse, but the intergonial width increased more in the bi-cortical group. The study suggested that both methods of skeletal fixation had similar postoperative stability.

Fronto-facial monobloc distraction in syndromic craniosynostosis. Three-dimensional evaluation of treatment outcome and facial growth

The objectives of this study were to investigate the treatment effect and stability of fronto-facial monobloc distraction osteogenesis. Five consecutive patients who underwent monobloc distraction were included (aged 4.8-18.4 years). Three patients had Crouzon syndrome, one had Apert syndrome, and one had Pfeiffer syndrome. The evaluation included clinical records, serial cephalograms for at least 1-year follow up (average 24.6 months). The treatment and post-treatment changes were measured. The intracranial volume, upper airway volume and globe protrusion were calculated from CT before and after treatment. After distraction, the supraorbital region was advanced 15.3mm forward, the midface demonstrated forward advancement of 17.7 mm, 22.1mm and 23.1mm at orbitale, anterior nasal spine and A point, respectively. The downward movement was 2-3mm at maxillary level. The intracranial volume increased 11%; the upper airway volume increased 85% on average. Globe protrusion reduced 3.7 mm on average, which was 20% of underlying skeletal movement. Facial growth demonstrated forward remodelling of the supraorbital region, mild downward but no further forward growth of the midface. Monobloc distraction is effective for relieving related symptoms and signs through differential external distraction at different vertical levels of the face.

The inter-relationship between mandibular autorotation and maxillary LeFort I impaction osteotomies.

The purposes of the present investigation were to: 1)locate the instantaneous rotation center of mandible autorotation during maxillary surgical impaction; 2) identify the discrepancies between the resultant mandibular position following by maxillary surgical impaction and presurgical predictions, which use the radiographic condylar center as the rotation center for mandibular autorotation; and 3)find the interrelation between the magnitude of maxillary surgical impaction and the sagittal change of mandible. Ten patients underwent maxillary LeFort I impaction without concomitant major mandibular ramus split osteotomies were included. The preoperative (T0) and postoperative (T1) lateral cephalograms were used to evaluate the surgical changes and locate the center of rotation of mandibular autorotation with Reuleaux method. Prediction errors were measured by comparing the predicted (Tp) and postoperative (T1) cephalometric tracings. The magnitude of the maxillary surgical impaction was compared to the positional changes of mandible after mandibular autorotation with correlation and regression analysis. The results demonstrated that the centers of mandibular autorotation located 2.5 mm behind and 19.6 mm below the radiographic condylar center of the mandible in average with large individual variations. By using the radiographic condylar center of the mandible to predict the mandibular autorotation would overestimate the horizontal position of chin by 2 mm and underestimate the vertical position of chin by 1.3 mm following an average of 5 mm surgical maxillary impaction. The magnitude of maxillary impaction was highly and positively correlated to the horizontal displacement of chin position. The rotation centers of mandibular autorotation following by maxillary LeFort I impaction osteotomies might not usually locate at the radiographic condylar center of the mandible also with large individual variations in their positions. Surgeons and orthodontists should be aware of the horizontal and vertical discrepancies of chin positions while planning a two-jaw surgery by using the radiographic center of mandibular condyle as the rotation center in mandibular autorotation.

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.

The Effect of early physiotherapy on the recovery of mandibular function after orthognathic surgery for Class III correction: part I--jaw-motion analysis.

The aim of this prospective study was to compare the mandibular range of motion in Class III patients with and without early physiotherapy after orthognathic surgery (OGS). This study consisted of 63 Class III patients who underwent 2-jaw OGS. The experimental group comprised 31 patients who received early systematic physical rehabilitation. The control group consisted of 32 patients who did not have physical rehabilitation. Twelve variables of 3-dimensional (3D) jaw-motion analysis (JMA) were recorded before surgery (T1) and 6 weeks (T2) and 6 months (T3) after surgery. A 2-sample t test was conducted to compare the JMA results between the two groups at different time points. At T2, the JMA data were measured to be 77.5%-145.7% of presurgical values in the experimental group, and 60.3%-90.6% in the control group. At T3, the measurements were 112.2%-179.2% of presurgical values in the experimental group, and 77.6%-157.2% in the control group. The patients in the experimental group exhibited more favorable recovery than did those in the control group, from T1 to T2 and T1 to T3. However, after termination of physiotherapy, no significant difference in the extent of recovery was observed between groups up to 6 months after OGS.

Functional and aesthetic approach to adult unoperated Möbius syndrome: orthognathic surgery followed by bilateral free gracilis muscle transfers.

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