• Journal of Periodontal and Implant Science
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• v.31 no.3
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• pp.581-595
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• 2001

In performing implant procedures in the anterior portion of the maxilla, many difficulties exist because of anatomical reasons, such as the proximity of the nasal floor, lateral extension of the incisive canal, and labial concavity. On the other hand, in the posterior region of the maxilla, there is often insufficient recipient bone between the maxillary sinus and alveolar ridge due to alveolar ridge resorption and pneumatization of the maxillary sinus. In order to perform implants in such regions, ridge augmentation procedures such as onlay bone graft, guided bone regeneration, and maxillary sinus grafting are performed. In studies of Caucasians, use of autograft from mandibular symphysis has been reported to be highly successful in maxillary sinus grafting. However, in a clinical study of Koreans, autograft of mandibular symphysis has been reported to have significantly low success rate. It has been hypothesized that this is because of insufficient cancellous bone due to thick cortical bone. In order to test this hypothesis, bone quality and morphology of Koreans can be compared with those of Caucasians. In this study, the bone density and morphology of the cortical bone and cancellous bone in the mandibular symphysis of 35 Korean cadavers were evaluated. The following results were obtained: 1. In terms of bone density, type I, type II, and type III consisted of 1.4%(3/213), 72.3%(154/213), and 26.3%(56/213) of the cross-sectioned specimens, respectively. In general, the bone density tended to change from type II to type III, as cross-sectioned specimens were evaluated from the midline to the canine. Type IV wasn't observed in this study. 2. The distance between the root apex and the lower border of the cancellous bone was 18.34mm-20.59mm. Considering that the bone has to be cut 5mm below the root apex during the procedure, autografts with about 15mm of vertical thickness can be obtained. 3. The thickness of cortical bone on the labial side increased from the root apex to the lower border of the mandible. The average values ranged from 1.43mm to 2.36mm. 4. The labio-lingual thickness of cancellous bone ranged from 3.43mm to 6.51mm. The thickness tended to increase from the apex to the lower border of the mandible and decrease around the lower border of cancellous bone. From the above results, the anatomic factors of the mandibular symphysis (bone density, thickness, quantity and length of the cortical bone and cancellous bone) didn't show any difference from Caucasians, and it cannot be viewed as the cause of failure in autografts in the maxillary sinus for implants.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.27 no.5
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• pp.472-477
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• 2005

This study investigated the mandibular fractures that were treated at the Seoul National University Boramae Hospital in order to analyze the characteristics of mandibular fractures and the relationship between the causes and injury patterns. A total of 141 patients with mandibular fractures who were treated between 1996 and 2004 were analyzed retrospectively. The male to female ratio in the patient group was 5.13:1, and the mean age was 33.7 years. The most common etiologic factor was assaults (45.4%), and which was followed by activities associated with daily-life (40.4%) includeding falls, stumbling, collisions, and traffic accidents (11.3%). Single fracture sites were present in 75 patients (53.2%), two or more fracture sites were observed in other patients, and a total of 211 fracture sites were observed. The mandibular angle fractures (46.7%) was the most common in case of single fractures, and symphysis and angle fractures (45.4%) was most common in multiple fractures. Through out overall fracture sites, the most common fracture site was the symphysis (41.2%), followed by the angle (32.2%) and condyle (18.5%). Among assault and falls-related injuries, the common involving sites were the symphysis, and followed by the body and condyle. In case of traffic accidents, the symphysis fracture was the most common, and which was followed by the condyle and angle fractures. This study documented the characteristics of the mandibular fractures. The results demonstrate that preventive measures according to these characteristics will need to be implemented in order to minimize the risk of maxillofacial injuries.

• 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 korean journal of orthodontics
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• v.28 no.5 s.70
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• pp.763-774
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• 1998

The purpose of this study was to evaluate the morphology of mandibular symphysis and location of lower incisor under the influence of the craniofacial skeleton in skeletal Class III malocclusion. The sample consisted of 132 adults who have severe Class III malocclusion(prognathism group, 33 males and 33 females), and who have normal occlusion(normal group, 33 males and 33 females). They had not received any orthodontic treatment or orthognathic surgery. The lateral cephalograms were evaluated. The results were as follows : 1. Prognathism group were larger than normal group in comparison of facial skeleton (p<0.05) with the exception of ${\angle}FH-Pal$, ${\angle}SNA$. 2. In the morphology of symphysis, measurements of anteroposterior width(LaABBW, LiABBW, SW) of prognathism group were significantly less than that of normal group(p<0.001). 3. In the correlative analysis between the craniofacial skeleton and symphysis measurements of prognathism group, vertical measurements in relation with cranial base and mandibular plane showed reverse correlationship with anteroposterior width of symphysis(LiACBW, LaACBW, LiABBW, SW)(p<0.05). But, there was not distinct difference between horizontal skeletal measurements and symphysis measurements(p>0.05). 4. The probability by regression test between vertical measurements(${\angle}SN-Mn,\;{\angle}FMA,\;{\angle}Pal-Mn,\;{\angle}LFH$) and symphysis measurements(LiACBW, LiABBW, SW, ${\angle}LISA$) were very high(p<0.001).

• The Journal of the Korean dental association
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• v.57 no.6
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• pp.344-351
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• 2019

Skeletal Class III malocclusion is a relatively common form of malocclusion in Korea. In borderline cases where only mild skeletal discrepancy exists and if worsening of the facial profile is expected as a result of premolar extraction, mandibular full arch distalization with miniscrews is the treatment of choice. The purpose of this study was to investigate the pattern of tooth movement and evaluate the stability of mandibular full arch distalization and to identify correlation between stability and factors such as initial skeletal pattern, dental changes during treatment and alveolar bone in symphysis region using lateral cephalograms.

• The korean journal of orthodontics
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• v.26 no.5 s.58
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• pp.509-522
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• 1996

By studying the relationship between the morphology of mandibular symphysis and craniofacial morphology in classIII malocclusion, this study aims at deciding whether the morphogy of mandibular symphysis can be used as a predictor on the growth of mandible. The materials used for this study were the cephalometric radiographs of male class III malocclusion. The subjected age groups were 10-12(G1 group) and 20 and above(G2 group): 50 were selected from each group. Each group was again divided, according to the ratio of symphysis, into Large(L), Average(A), and Small(S). The results of this study were summarized as follows: 1. In average the ratio of symphysis, G2 group showed significantly bigger than G1 group(p<0.05) 2. In both G1 and G2 groups, the ratio of symphysis had no relationship with the measurements on the cranial base and the maxilla(p>0.05). 3. In both G1 and G2 groups, there was not distinct difference in the antero-posterior positions among L, A, S subgroups. 4. L and A subgroups showed significantly larger than S subgroup in lower gonial angle and chin angle in G1 group (p<0.05). 5. In the measurements on the vortical relation of the face, anterior total face height(ATFH) and anterior lower face height(ALFH) of L subgroup were significantly larger than that of S subgroup in G1 group(p<0.05) and also mandible showed a tendency to grow downward vertically. 6. In the measurements on the tooth position and inclination, L subgroup showed as compared with S subgroup a tendency of extrusion of maxillary and mandibular teeth in G1 group, but G2 group showed such tendency only in mandibular teeth. 7. In the measurements on the abnormal growth prediction by Schulhof, in G1, there was no significant difference among L, A, S sugroups. 8. In the correlative analysis of the ratio of symphysis and other measurements, G1 group showed significant correlationships in chin angle, PP/MP angie, ANS-Me and other, while G2 group showed the same only in MP-LIT and MP-LMMC(p<0.05, p<0.01). In summarizing the above, in the G1 group, consisting of young males, no difference was noted in horizontal relation between L and S subgroups; in vertical relation, L subgroup showed a stronger tendency of downward growth of mandible than S subgroup. In adult male G2 group, however, no distinct morphological difference of craniofacial complex by the ratio of symphysis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.31 no.1
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• pp.82-88
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• 2005

Treatment methods of mandibular condylar fracture were conservative and surgical method. Surgical method of mandibular high condylar fracture was very difficult because approach and internal fixation of small size fracture fragment were difficult. So there is a tendency to select conservative method over surgical method for guiding a stable occlusion and avoiding TMJ disorder and growth disturbance, minimizing pain and deviation during function. But, in case of mandibular high condylar fracture patient who has no biting teeth on posterior teeth area, guiding a stable occlusion and conservative functional treatment were very difficult. In this case, patient was 62years old male. He had fracture of mandibular symphysis, right mandibular body, left mandibular high condyle. We treated the patient for mandibular symphysis and right mandibular body fracture area with surgical method. But left mandibular high condylar fracture area was difficult to treat with surgical method. So we selected a conservative functional method on left mandibular high condylar fracture area. We intended recovery of vertical dimension and stable occlusion with implantation of immediate provisional implant on maxillar and mandibular posterior teeth area, and temporary crown. And then patient did mandibular functional movement and his mandibular function was recoverd.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.39 no.5
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• pp.238-241
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• 2013

Lateral and superior-lateral dislocations of the intact condyle are a rare complication, following traumatic insult to the mandible. We report an unusual case of a 54-year-old male patient who experienced both types of dislocations of the intact condyles with symphysis fracture following a road-traffic accident. Under general anesthesia, conventional manipulation was unsuccessful in relocating the condyles into the glenoid fossa. After applying a percutaneous traction force, using a bone traction hook placed at the sigmoid notch, the displaced intact mandibular condyles were repositioned, and the symphyseal fracture was finally reduced and fixed. The mouth opening was within normal limits, and favorable occlusion was confirmed one month postoperatively. To our knowledge, this is the first case of dislocation of both intact condyles--associated with symphysis fracture--being reduced with bone traction hook.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.40 no.6
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• pp.285-290
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• 2014

Objectives: We compared resorbable plates with titanium plates for treatment of combined mandibular angle and symphyseal fractures. Materials and Methods: Patients with mandibular angle and symphysis fractures were divided into two groups. The control (T) group received titanium plates while the experimental (R) group received resorbable plates. All procedures were carried out under general anesthesia using standard surgical techniques. We compared the frequency of wound dehiscence, development of infection, malocclusion, malunion, screw breakage, and any other technical difficulties between the two groups. Results: Thirteen patients were included in the R group, where 39 resorbable plates were applied. The T group consisted of 16 patients who received 48 titanium plates. The mean age in the R and T groups was 28.29 and 24.23 years, respectively. Primary healing of the fractured mandible was obtained in all patients in both groups. Postoperative complications were minor and transient. Moreover, there were no significant differences in the rates of various complications between the two groups. Breakage of 3 screws during the perioperative period was seen in the R group, while no screws or plates were broken in the T group. Conclusion: Resorbable plates can be used to stabilize combined mandibular angle and symphysis fractures.

• The Journal of the Korean dental association
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• v.39 no.4 s.383
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• pp.246-250
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• 2001