• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.49 no.3
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• pp.107-113
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• 2023

Bimaxillary transverse width discrepancies are commonly encountered among patients with dentofacial deformities. Skeletal discrepancies should be diagnosed and managed appropriately with possible surgical corrections. Transverse width deficiencies can present in varieties of combinations involving the maxilla and mandible. We observed that in a significant proportion of cases, the maxilla is normal, and the mandible showed deficiency in the transverse dimension after pre-surgical orthodontics. We designed novel osteotomy techniques to enhance mandibular transverse width correction, as well as simultaneous genioplasty. Chin repositioning along any plane is applicable concomitant with mandibular midline arch widening. When there is a requirement for larger widening, gonial angle reduction may be necessary. This technical note focuses on key points in management of patients with transversely deficient mandible and the factors affecting the outcome and stability. Further research on the maximum amount of stable widening will be conducted. We believe that developing evidence-based additional modifications to existing conventional surgical procedures can aid precise correction of complex dentofacial deformities.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.5
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• pp.447-452
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• 2006

Purpose: In order to clarify the correlation of mandibular setback using bilateral intraoral vertical ramus osteotomy (BIVRO) and post-surgical transverse mandibular width (TMW), this study examined the pre- and postsurgical changes in hard and soft tissues of TMW and the relationship of TMW and the amount of mandibular setback. Patients and Methods: One-hundred seven patients who had undergone BIVRO were evaluated radiographically and clinically. A comparison study of the changes in hard and soft tissue after surgery in all 107 patients was performed with preoperative, 1 month, 3 month, 6 month and 1 year postoperative posteroanterio cephalograms and clinical photographs by tracing. And this changes were evaluated in parts to amounts of mandibular setback. Results: Statistically significant increases of TMW in hard and soft tissue from preoperative to postoperative 1 month were seen. TMW in hard tissue from 1 month to 1 year postopertive were gradually decreased. TMW in soft tissue was not changed uniformly but almost equal to pre-operative width. And there was no significant correlation between TMW and amount of mandibular setback. Conclusions: The results show that mandibular setback using BIVRO did not significantly influence increasing of TMW in soft tissue.

• The korean journal of orthodontics
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• v.33 no.2 s.97
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• pp.85-90
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• 2003

The symphyseal mandibular fractures due to accidents happened in form of collapsed transeverse arch and multiple teeth loss. And the collapsed transverse arch in mandible occurs with unilaterally or bilaterally. So that patient needs to recover arch width. Conventional approaches, however, we difficult to get appropriate transverse arch correction. Distraction osteogenesis is a unique form of clinical tissue engineering and biologic process of new bone formation between bone segments that are gradually separately by incremental traction. Distraction osteogenesis is considered that great potential for correcting transverse mandibular deficiencies. Tn this paper, distraction osteogenesis applied to patients who had a unilateral or bilateral collapsed arch width in mandible. But it was necessary secrutinize consideration about periodontal conditions, biomechanical vectors, TMJ adaptations, and neuromuscular change during distraction osteogenesis period.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.5
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• pp.480-488
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• 2008

Orthodontists often treat cases which are difficult to treat with conventional orthodontics. In such cases, it could be treated with surgical procedures with the help of an oral surgeon. Especially, transverse deficiency of the mandible can be corrected by widening the transverse width of mandibular symphysis, using distraction osteogenesis. Transverse widening of mandibular sympysis is known as a safe treatment but still complications could occur during the treatment. We are reporting some complications of cases that mandibular symphysis transverse widening were applied. Some cases showed complications because of the inappropriate osteotomy line. Since straight vertical osteotomy line was inclined to the left, only the left bony segment was likely to expand. According to bio-mechanical considerations, it will be better to perform a step osteotomy, cutting the eccentric area of the alveolar crest and the centric area of the basal symphyseal area. Complications could also occur by the failure of the distraction device. The tooth borne distraction device was attached on the lingual side of the tooth with composite resin. During the distraction period, it was impossible to obtain appropriate distraction speed and rhythm because of frequent fall off of the distraction device. Therefore, distraction device should be attached firmly with orthodontic band or bone screw, etc. Tooth mobility increasement could also occur as a complication. 'Walking teeth phenomenon' was observed during the distraction period, showing severe teeth mobility and pain during mastication. These symptoms fade out during the consolidation period. Since the patient could feel insecure and uncomfortable, it should be notified to the patient before the procedure. Finally, alveolar crestal bone loss could occur. Alveolar crestal bone loss occurred because of lack of distraction device firmness and teeth trauma caused by lower lip biting habit. Therefore, adequate firmness of the distraction device and habit control will be needed.

• The Journal of the Korean dental association
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• v.55 no.6
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• pp.400-410
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• 2017

Approximately 30% of adult patients who want orthodontic treatment have transverse discrepancy with insufficient width of the maxilla. Particularly, in Class III patients requiring orthognathic surgery, the frequency of insufficient width of the maxillary arch related to respiratory problems is high. We report a case of non-surgical maxillary expansion using a Hyrax type expander with an orthognathic surgery, based on the reports that the ratio of non-fused midpalatal suture is not high in adults. A 30 years and 2 months old woman with a long face showed an Angle Class III with a vertical growth pattern. Class III molar and canine relation, anterior edge bite, and mandibular incisor compensatory lingual inclination were observed. The posterior buccal overjet seemed to be appropriate, but I diagnosed that there was a transverse discrepancy, for the following reasons. The inter-canine and inter-molar widths were sufficient but excessive lingual inclination of the mandibular molars was observed when assessing the bucco-lingual inclination based on the center of resistance of the maxillary and mandibular first molar. For this reason, it was expected that intercuspal interference would occur during orthodontic decompensation. Therefore, slow maxillary expansion using Hyrax type expander was performed and 2-jaw rotation surgery was performed to improve aesthetic and occlusion. Adults can also improve width discrepancy by non-surgical methods, which can avoid SARPE requiring additional surgery or segmental surgery lacking stability and predictability.

• The korean journal of orthodontics
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• v.48 no.1
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• pp.39-47
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• 2018

Objective: The aim of this study was to establish the normative data of dentofacial transverse dimensions according to the skeletal maturation stage in Korean adolescents with good occlusion, assess gender differences and determine correlations between transverse variables. Methods: A total of 577 Korean subjects between ages 7 to 19 years and exhibiting skeletal Class I occlusion were categorized by skeletal maturation index (SMI) of Fishman using hand-wrist radiographs. Dentofacial transverse dimensions were assessed using posteroanterior cephalograms. Independent two-sample t-tests were used to analyze differences between genders. Pearson correlation coefficient was used to determine the correlation between transverse measurements. Results: Dentofacial transverse norms relevant to skeletal maturation stages were established. The average maxillomandibular width difference and ratio at growth completion was 22.16 mm and 77.01% for males; 23.70 mm and 74.06% for females, respectively. Males had greater facial, maxillary and mandibular widths compared to females at every SMI stage. The maxillary and mandibular intermolar widths showed the strongest correlation for both sexes (r = 0.826 for males, r = 0.725 for females). Conclusions: Dentofacial transverse norms of Korean adolescents were established according to developmental stage. All dentofacial widths were greater in males at growth completion. Maxillary and mandibular intermolar widths were strongly correlated. This study may serve as a guideline for the assessment of dentofacial transverse growth according to skeletal maturation stage in Korean adolescents with good occlusion.

• Journal of Oral Medicine and Pain
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• v.42 no.4
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• pp.109-115
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• 2017

Purpose: This study analyzed the effects of digastric muscle injury on mandibular growth in young rats. Methods: Fourteen 4-week-old Wistar rats were divided into 3 groups; experimental group A (n=6) with unilateral (right) shortening of the posterior digastric muscle, experimental group B (n=6) with bilateral shortening of the posterior digastric muscles, and control group C (n=2) who underwent a sham operation. Eight weeks after the operation all animals were sacrificed and the outcomes were compared using body weight evaluation, mensurations on lateral radiograph of hemimandibles and histological evaluation. Results: There was no significant difference between groups A and B in body weight gain. Comparison of the mean values of hemimandible distance on radiograph was performed. The difference in group mean value of mandible-related distances was analyzed using the Wilcoxon test (rank sum test) and a comparison of the homonymous distances of group A and B was performed using the Mann-Whitney test. There were differences between sides in mandibular length in group B and mandibular ramus height and transverse width of the condyle in group A (all, p<0.05). There were differences in condylar height and mandibular length on the left side between groups A and B (p<0.05). Histologic examination of temporomandibular joint showed similar findings in all specimens. Conclusions: Injury of the posterior belly of the digastric muscle during the rat growth period induced shortening of mandibular ramus height and transverse width of the condyle. It can be inferred that trauma to the posterior belly of the digastric muscle affects horizontal and vertical growth of the mandible.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.3
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• pp.232-240
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• 2008

Purpose: This study was performed to evaluate transverse changes of proximal segment after bilateral sagittal split ramus osteotomy (BSSRO) using 3-D CT in mandibular prognathism. Patients and methods: Twenty-two patients who underwent BSSRO for mandibular set-back in class III malocclusion without facial asymmetry were examined. Miniplates were used for the fixation after BSSRO. Facial CT was taken before and after BSSRO within 3 months. Frontal-ramal inclination (FRI), inter-gonial width (IGW) and intercondylar width (ICW) were measured in 3-D CT images using V-works $4.0^{TM}$ program. Student t-test was used to compare the changes between pre- and post-operative measurements using SPSS 10.0 program. Results: 1. Mean peroperative FRI value ($12.87{\pm}3.43^{\circ}$) was slightly increased to postoperative value ($14.13{\pm}3.72^{\circ}$) (p < 0.05). The average FRI increased 10.42% and the range was from $-2.46^{\circ}$ to $3.34^{\circ}$. 2. Mean peroperative IGW ($99.01{\pm}5.36$) was slightly decreased to postoperative IGW ($96.51{\pm}5.88mm$) (p < 0.05). The average IGW decreased 2.52 % and the range was from $-6.61^{\circ}$ to 0.91 mm. 3. Mean preoperative ICW ($125.01{\pm}5.30mm$) was slightly decreased to postoperative ICW ($125.40{\pm}5.45mm$) (p < 0.05). There is no significant difference between pre- and post-operative ICW. 4. There was significant correlationship between FRI difference and IGW difference (p < 0.05). Conclusions: These results indicate that the lower ramus of the proximal segment is moved inward after BSSRO procedure for mandibular set-back.

• The korean journal of orthodontics
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• v.32 no.2 s.91
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• pp.117-127
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• 2002

The purpose of this study was to compare the arch width of the hyperdivergent group with that of the neutral group in Class III malocclusion based on the vertical patterns and to compare the arch width of Class III neutral group With that of normal occlusion group based on sagittal patterns. The subjects consisted of 118 pairs of studty casts, divided into three groups , 37 Class III hyperdivergent group(18 males and 19 females, SN-Mn plane angle>39.5$^{\circ}$), 40 Class III neutral group(20 males and 20 females, SN-Mn plane angle : 32 ${\pm}$ 2.5$^{\circ}$) and 41 Class I normal occlusion group(20 males and 21 females). The intercanine, interpremolar, and intermolar width of the maxillary and mandibular study casts were measured, then the ratios of dental width to basal width and mandibular width to maxillary width were obtained. Basal arch width and dental arch width were measured to obtain the pure basal arch relation in transverse plane as ruled out the transverse dental compensation. The results were as follows 1. There were no significant differences in any ratios between Class III hyperdivergent group and Class III neutral group as different vertical pattern. 2. As the ratios of dental arch width to basal arch width between normal occlusion group and Class III neutral group were compared, the maxillary teeth flared buccally to the basal bone, and the mandibular teeth tilted lingually to the basal bone in Class III neutral group. 3. The ratios of mandibular arch width to maxillary arch width in basal arch level were significantly different in all regions. Maxillary basal arch width of Class III neutral group was narrower than that of normal occlusion group. 4. The ratios of mandibular arch width to maxillary arch width in teeth level were not significantly different between normal occlusion group and Class III neutral group. In spite of discrepancies of maxillary and mandibular basal arch width, the dental arch width of Class III malocclusion group compensated very well. At the presurgical orthodontic treatment in clinic, it would not be desirable to decompensate for compensated dental arch width too much, for obtaining an appropriate arch compatibility and good results for orthognathic surgery.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.4
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• pp.356-364
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• 2006

Transverse mandibular deficiency has a many problem in growing patients. Therefore, Mandible symphysis widening is recommended. A new surgical technique has been developed to widen the mandible. The purpose of this study is to report the effect of mandibluar symphyseal distraction osteogenesis by use of bone-borne type distractor. The surgical procedure was accomplished under general anaesthesia with step-line osteotomy. Bone-borne type distractor was used to generally widen the mandible. The expansion achieved in the mandible was 8.31mm at the device, 6.32mm at the canines, 4.06mm at the first molars. The symphyseal distraction gaps were bridged by new bony regeneration. Mandibular symphseal distraction osteogenesis increased mandibular arch width, stabilized occlusion, and corrected dental crowding.