• The korean journal of orthodontics
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• v.22 no.3 s.38
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• pp.657-673
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• 1992

Orthodontic treatment of cleft patients is difficult as the growth is different from that of normal ones. So it is very important to know the characteristic features of the craniofacial morphology and growth pattern in unilateral cleft lip and palate patients. The materials for this study consisted of 55 normal males and 50 unilateral cleft lip and palate ones who received cheiloplasty and palatoplasty previously. The cleft subjects were divided into 4 groups according to their ages kto find out the growth pattern of hard and soft tissue, and to compare the features with those of normal ones. Each cephalogram analysed by McNamara method and others. The obtained results were as follows 1. In the unilateral cleft lip and palate subjects, forward growth of the maxilla was smaller than that of normal ones from 9 years old. So the maxilla was retruded. The maxillary incisors were severely retruded in all age groups. 2. The mandibular overall length and its anteroposterior position did not show any significant differences between two groups. But the height of ramus was very short and the mandible had vertical growth tendency to compensate for undergrowth of the maxilla in cleft subjects after 12 years of age. 3. Horizontal growth of the soft tissue in middle face was smaller than that of any other facial region from 9 years old. The vertical growth rate of upper lip was decreased as growing old. 4. In cleft subjects, the upper and lower facial component angle and the facial convexity angle were large. So their facial profile changed to straight or concave as growing old.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.3
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• pp.218-224
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• 2011

Purpose: The purpose of this study is to evaluate the post-operative skeletal stability after surgical correction of patients with mandibular prognathism by bilateral sagittal split ramus osteotomy (BSSRO) and to evaluate the horizontal relapse tendency after the surgery. Methods: Twenty-six patients with Class III dental and skeletal malocclusion were selected for this retrospective study. Fifteen of them underwent BSSRO for mandibular setback and eleven of them underwent two-jaw surgery (Lefort I and BSSRO). In each patient, lateral cephalometric radiographs were taken pre-operatively, post-operatively within 1 week, and post-operatively after eight months. After tracing of the cephalometric radiographs, various parameters were measured. The analyses were done by linear measurement to evaluate the change in position of hard tissue B point, pogonion and mandibular plan angle by examination on lateral cephalograms. Results: The horizontal relapse rate was 27.1% at B point and 31.6% at pogonion in patients who underwent BSSRO. The horizontal relapse rate of the group where the amount of correction exceeded 10 mm was 25.69% at B point. Conclusion: There were no statistical differences on the magnitude of setback and direction of rotation of the mandible in mandibular stability. There were also no statistical differences between single mandibular surgery and two-jaw surgery for mandibular stability.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.46 no.1
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• pp.41-48
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• 2020

Objectives: One of the most common complications of bilateral sagittal split ramus osteotomy (BSSRO) is neurosensory impairment of the inferior alveolar nerve (IAN). Accurate preoperative determination of the position of the IAN canal within the mandible using cone-beam computed tomography (CBCT) is recommended to prevent IAN dysfunction during BSSRO and facilitate neurosensory improvement after BSSRO. Materials and Methods: This randomized clinical trial consisted of 86 surgical sites in 43 patients (30 females and 13 males), including 21 cases (42 sides) and 22 controls (44 sides). Panoramic and lateral cephalographs were obtained from all patients. In the experimental group, CBCT was also performed from both sides of the ramus and mandibular body. Neurosensory function of the IAN was subjectively assessed using a 5-point scale preoperatively and 7 days, 1 month, 3 months, 6 months, and 12 months post-surgery. Data were analyzed using Fisher's test, Spearman's test, t-test, linear mixed-model regression, and repeated-measures ANCOVA (α=0.05, 0.01). Results: Mean sensory scores in the control group were 1.57, 2.61, 3.34, 3.73, and 4.20 over one year and were 1.69, 3.00, 3.60, 4.19, and 4.48 in the CBCT group. Significant effects were detected for CBCT intervention (P=0.002) and jaw side (P=0.003) but not for age (P=0.617) or displacement extent (P=0.122). Conclusion: Preoperative use of CBCT may help surgeons to practice more conservative surgery. Neurosensory deficits might heal faster on the right side.

• Development and Reproduction
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• v.17 no.3
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• pp.257-268
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• 2013

Morphometric changes in the Ussurian bullhead, Leiocassis ussuriensis, and the Korean bullhead, Pseudobagrus fulvidraco, were observed during the early period of growth. Yolk length, yolk height, and yolk volume in the two species decreased within 9 days post-hatching (DPH) (p<0.05). The body lengths and body heights of both species increased gradually to 150 and 130 DPH, respectively (p<0.05). The horizontal distance between the anteriormost extension of the head and the anterior insertion of the pectoral fin, the anteriormost extension of the head ${\times}$ the verticality position of the anterior insertion of the primary dorsal fin rays, and the anterior insertion of the primary dorsal fin ${\times}$ the anterior insertion of the pectoral fin were greater in the Korean bullhead than in the Ussurian bullhead (p<0.05). However, the relative sizes of the head region, pectoral fin, ventral fin, and anal fin were greater in the Ussurian bullhead than in the Korean bullhead (p<0.05), and relative body depth and the size of the outer-mandible barbel were greater in the Korean bullhead than in the Ussurian bullhead (p<0.05). The growth curves of the morphometric characteristics of both species were divided into three types.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.4
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• pp.338-347
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• 2001

Purpose: This is to review the cases of posterior maxillary segmental osteotomies to regain the interarch spaces for dental implants in the posterior mandible. Materials & Methods: Seven patients who presented with alveolar extrusion of upper posterior molars underwent segmental osteotomies by single-stage Kufner's buccal approach under the intravenous sedation and local anesthesia. The posterior maxillary cento-alveolar segments were repositioned upward using pre-fabricated palato-occlusal resin splints and immobilized with osteosynthesis microplates and screws. Dental implants were installated simultaneously. The regained spaces, tooth vitality, periodontal healing, relapse, tenderness on function, and complications including maxillary sinus involvements were evaluated periodically for over one year after the surgeries. Results: The single-tage procedures were completed within 80 minutes without any surgical complications. The posterior maxillary segments were repositioned upward to regain the interarch spaces ranging from 2.5 to 5.5mm. All teeth involved in the procedures keep their vitalities. The repositioned segments were maintained showing neither evidence of periodontal break-down nor tenderness to function. One patient whose segments had not been immobilized by osteosynthesis plate resulted in 2mm down-ward relapse in post-operative 8 months. A case of postoperative nasal bleeding from the posterior-lateral wall resulted in oroantral fistula and chronic maxillary sinusitis later. Conclusion: The extruded dento-alveolar segments of the posterior maxilla were repositioned properly by Kufner's one-stage segmental osteotomies. One microplate can be of help to keep the position until the osseous healing enough to support the masticatory force.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.4
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• pp.294-305
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• 2009

Purpose: This retrospective study evaluated the changes in hyoid bone and tongue positions as well as oral cavity volume after mandibular setback by BSSRO. Materials and Methods: 18 Koreans who underwent BSSRO to correct mandibular prognathism were studied. Lateral cephalograms were taken and traced preoperatively (T0), immediately (T1) and approximately 6 months postoperatively (T2). Submentovertex radiograghs were taken and traced before surgery (T0) and about 6 months after surgery (T2). The area and volume of oral cavity, the vertical and horizontal dimensions of the hyoid bone and tongue dorsum were measured. Results: Mandibular setback surgery resulted in a significant reduction of lower oral cavity volume. The hyoid bone displaced posteroinferiorly immediately after surgery, and it tended to return to its original vertical position at 6 month after mandibular setback by BSSRO. The retropalatal space around tongue was maintained and the retrolingual space around tongue was reduced immediately postoperatively. The readaptation of tongue was not evident for that the follow up period was not long enough. No significant statistical correlations between the amounts of mandibular setback and the changes of oral cavity volume were observed. Conclusion: Mandibular setback surgery resulted in a significant reduction of lower oral cavity volume, which was most likely attributable to the posterior movement of the mandible. More subjects and long-term observations should be performed to assess the changes of oropharyngeal configuration following mandibular setback surgery.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.4
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• pp.407-413
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• 2000

To evaluate the stability after orthognathic surgery in cleft lip and palate patients using rigid fixation, 20 patients underwent primary repair in childhood and later developed a jaw deformity and malocclusion that required orthognathic surgery were reviewed. Two groups, one of 10 patients performed Le Fort I osteotomy with sagittal split ramus osteotomy and one of 10 patients with sagittal split ramus osteotomy of the mandible, were evaluated. Each group had unilateral cleft only and all alveolar cleft sites had been grafted with autogeneous bone before the orthognathic surgery. The amount of surgical movement and relapse were compared in both horizontal and vertical dimensions. Two-jaw surgery group was more stable than mandibular surgery only group in mandibular position (p< 0.05). Statistically significant relapse was observed in mandibular skeletal point in mandibular surgery group (p<0.05). There was no statistically significant relapse in the skeletal point of two-jaw surgery group. However, the correlation between the horizontal surgical movement and relapse was detected (r = 0.88). This correlation indicates the need of overcorrection. The presence of scar tissues and relatively deficient maxillary bone could be attributed to this close relation between the surgical change and relapse.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.5
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• pp.265-271
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• 2003

Skeletal relapse is known as a complication following orthognathic surgery of mandibular prognathism and occurring during intermaxillary fixation period. Therefore relapse of teeth and skeleton during intermaxillary fixation period is considered as a important problem of orthognathic surgery. In this study, cephalolateral radiographs taken at pre-operation, immediate post-operation and after release of intermaxillary fixation were measured for evaluation of dental and skeletal relapse in 30 cases. The cases were classified as screw fixation group and plate fixation group, then we compared magnitude of dental and skeletal changes of each group. The results were as follows 1. The $\underline{1}$ SN angle increased at immediate post-operation with a mean value of $0.12^{\circ}$ and at intermaxillary fixation period with a mean value of $0.43^{\circ}$ (p>0.05). 2. The $\overline{1}$ MP angle decreased with a mean value of $0.14^{\circ} at immediate post-operation and with a mean value of $1.28^{\circ} during intermaxillary fixation period but there were not significant difference(p>0.05). 3. There were not significant difference in magnitude of dental position changes between screw fixation group and plate fixation group(p>0.05). 4. Gonial angle increased with a mean value of $0.62^{\circ} during intermaxillary fixation period. Each group showed changes of gonial angle during intermaxillary fixation period but there were not significant difference(p>0.05).

• Journal of Korean Dental Science
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• v.7 no.1
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• pp.31-37
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• 2014

Dentigerous cyst (DC) is an odontogenic cyst associated with the crown of an impacted, embedded, unerupted, or developing tooth. It is the second most common type of odontogenic cysts, accounting for 14% to 24% of all jaw cysts. Although these cysts occur more frequently during the second and third decades of life, they can also be found in children and adolescents in the mixed dentition stage. Treatment of the odontogenic cyst involves enucleation or marsupialization/decompression methods. The latter approach is preferred for larger cysts, and it is especially helpful in adolescent patients in conserving the unerupted permanent successors. The aim of treatment for DC is the complete elimination of pathology and maintenance of dentition with minimal surgical intervention. Recently defined criteria for the selection of treatment modality include the cyst size and location of the cyst, patient age, dentition involved, stage of root development, position of the tooth involved in the jaw, and relationship with the surrounding vital structure. Marsupialization or decompression technique has been advocated by several authors for treating DCs among young patients. In this conservative technique, the creation of an accessory cavity helps relieve intra-cystic pressure and accelerate the healing of cystic lesion. This technique has been successfully performed and is indicated for growing children and adolescents. Here, we report a large cyst lesion in the mandible treated by marsupialization for conservative management. In conclusion, successful reduction in size was achieved, and intraoperative complication could be prevented.

• Journal of the korean academy of Pediatric Dentistry
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• v.5 no.1
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• pp.64-75
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• 1978

In order to know cephalometric norms for the preschool children, this roentgeno cephalometric study was undertaken in each 50 Korean male and female children of primary dentition age from 4 to 5 year. The following results were obtained. 1. In the skeletal analysis, there was no significant difference between male and female in angular measurement and the linear measument of the male was generally greater than that of the female. 2. Saddle angle was $122.3^{\circ}$, articular angle was $147.6^{\circ}$, gonial angle was $119.4^{\circ}$ and the sum of each angle was $396.1^{\circ}$ in male and $396.6^{\circ}$ in female. 3. The ratio of mandibular body to anterior cranial base was about 1 : 0.91. 4. In the primary dentition, suggested that the nasion and point A move forward relative to sella turcica in a fashion, pogonion and point B are equal in angular position relative to plan S-N, bony chin and chin button was yet underdeveloped, and the forward growth of mandible was seen rapid than maxilla after 4 years. 5. Suggested that the percentage of anterior facial height to the posterior facial height were 64.4% in male and 64.1% in female. 6. Maxillary primary incisors was more upright than the permanent incisors, mandibular primary incisors was inclined lingually relative to the permanent incisor, and primary incisors was more upright than the permanent incisors. 7. Maxillary primary incisors in female was inclined labially than male. 8. In the the relationship of the upper lip and lower lip to the esthetic line, the upper lip was 2.11mm and the lower lip was 2.33mm front of the esthetic line.