• Imaging Science in Dentistry
• /
• 제48권1호
• /
• pp.51-57
• /
• 2018

Purpose: To perform a comparative analysis of the palatal bone thickness in Thai patients exhibiting class I malocclusion according to whether they exhibited a normal or open vertical skeletal configuration using cone-beam computed tomography (CBCT). Materials and Methods: Thirty CBCT images of Thai orthodontic patients (15-30 years of age) exhibiting class I malocclusion with a normal or open vertical skeletal configuration were selected. Palatal bone thickness was measured in a 3.0-mm grid pattern on both the right and left sides. The palatal bone thickness of the normal-bite and open-bite groups was compared using the independent t-test. The level of significance was established at P<.05. Results: The palatal bone thickness in the normal-bite group ranged from $2.2{\pm}1.0mm$ to $12.6{\pm}4.1mm$. The palatal bone thickness in the open-bite group ranged from $1.9{\pm}1.1mm$ to $13.2{\pm}2.3mm$. The palatal bone thickness was lower at almost all sites in patients with open bite than in those with normal bite. Significant differences were found at almost all anteroposterior sites along the 3 most medial sections (3.0, 6.0, and 9.0 mm lateral to the midsagittal plane)(P<.05). Conclusion: Class I malocclusion with open vertical skeletal configuration may affect palatal bone thickness, so the placement of temporary anchorage devices or miniscrew implants in the palatal area in such patients should be performed with caution.

• 대한소아치과학회지
• /
• 제28권4호
• /
• pp.643-648
• /
• 2001

III급 부정교합은 전치가 수평적으로 반대로 물리는 양상 때문에 치과의사뿐만 아니라 일반인에 의해서도 쉽게 발견되므로 비교적 조기에 치과를 찾는 빈도가 높다. 이러한 III급 부정교합 치료 시에 치과의사들이 사용할 수 있는 방법은 여러 가지가 있을 수 있으며 그 중 정형적 Face mask는 III급 부정교합에 기여하는 모든 요소 즉, 상악골 후퇴, 하악전돌, 낮은 전방하안면고경에 전반적으로 영향을 미치기 때문에 가장 폭넓게 적용가능하고 가장 짧은 기간에 극적인 결과를 나타내기 때문에 대부분의 발육중인 III급 증례에 적용될 수 있다. 이에 본원에 내원한 III급 부정교합 환아에서 Face mask를 적응함으로써 다음과 같은 결과를 얻었다. 1. 전치부 반대 교합이 상악골의 전방이동 하악골의 후하방 회전에 의해 해소되었다. 2. 경조직, 연조직에서 안모의 개선이 나타났다.

• 대한소아치과학회지
• /
• 제25권1호
• /
• pp.134-143
• /
• 1998

Twin Blocks are simple bite-blocks that effectively modify the occlusal inclined plane to induce favorably directed occlusal forces by causing a functional mandibular displacement. These devices use upper and lower bite-blocks that engage on occlusal inclined planes. Twin Blocks use the forces of occlusion as the functional mechanism to correct the malocclusion. To get an excellent result in the treatment by using the Twin Block appliances, proper case selection must be needed. Twin Block treatment is performed in two stages. Twin Blocks are used in the active phase to correct the anteroposterior relationship and establish the correct vertical dimension. Once this phase is accomplished, the Twin Blocks are replaced with an upper Hawley type of appliance with an anterior inclined plane, which is then used to support the corrected position as the posterior teeth settle fully into occlusion. The Twin Block is the most comfortable, the most esthetic ane the most efficient of all the functional appliances. Twin Blocks have many advantages compared to other functional appliances. Patients can wear Twin Blocks 24 hours per day and can eat comfortably with the appliances in place. From the moment Twin Blocks are fitted, the appearance is noticeably improved. There is less interference with normal function. Integration with conventional fixed appliances is simpler than with any other functional appliance. Twin Blocks allow independent control of upper and lower arch width. Appliance design is easily modified for transverse and sigittal arch development. The authors treated Class II malocclusion with Twin Blocks. and the results as follows; 1. Rapid profile improvement was achieved in 2-3 months. 2. There was excellent patient cooperation. 3. Severe overjet and overbite were reduced. 4. Class II molar relationship was changed to Class I.

• Archives of Plastic Surgery
• /
• 제32권5호
• /
• pp.547-554
• /
• 2005

Orthognathic surgery for Class III malocclusion requires an elaborate preoperative planning using cephalometries or Mock surgery models which enable the surgeon to anticipate postoperative skeletal changes of maxilla and mandible as well as dentition. After surgery, patient's satisfaction is greatly influenced by appearance of soft tissue change. Therefore, it is imperative to predict a relatively accurate soft tissue change prior to surgery. A 5 year retrospective study was designed to evaluate the soft tissue change after sagittal split osteotomy of ramus(SSRO) for class III malocclusion. Analyses of preoperative and postoperative anthropometric measurements were performed. Patients who were treated only by SSRO for class III malocclusion and could follow up for 6 months were studied. Among them, the patients who had history of cleft palate and lip or hemifacial microsomia were excluded. Soft tissue changes were estimated by using the frontal and lateral photographs. Skeletal changes were observed by measuring amount of set back and angular changes of mandible to the reference line by using cephalometries. Relapses were also measured 6 months after the operation. We could observe skeletal changes were more profound than soft tissue changes concerning amount of set back, but soft tissue changes were also profound in angle. Relapse was more profound in skeleton than soft tissue but the amount was not significant. In spite of the variables which may affect proper assessment of the soft tissue change after skeletal relocation, this study can serve as a guide for exact prediction of the postoperative change of soft tissue and skeleton.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제42권
• /
• pp.21.1-21.6
• /
• 2020

Background: Fibula free flap mandible reconstruction is the standard procedure after wide resection of the mandible. Establishment and maintenance of normal occlusion are important in mandible reconstruction both intraoperatively and after surgery. However, scar formation on the surgical site can cause severe fibrosis and atrophy of soft tissue in the head and neck region. Case presentation: Here, we report a case of severe soft tissue atrophy that appeared along with scar formation after mandibular reconstruction through the fibular free flap procedure. This led to normal occlusion collapse after it was established, and the midline of the mandible became severely deviated to the affected side that was replaced with the fibula free flap, leading to facial asymmetry. We corrected the malocclusion with a secondary operation: a sagittal split ramus osteotomy on the unaffected side and a sliding osteotomy on the previous fibula graft. After a healing time of 3 months, implants were placed on the fibula graft for additional occlusal stability. Conclusion: We report satisfactory results from the correction of malocclusion after fibula reconstruction using sliding fibula osteotomy and sagittal split ramus osteotomy. The midline of the mandible returned to its original position and the degree of facial asymmetry was reduced. The implants reduced difficulties that the patient experienced with masticatory function.

• 대한치과교정학회지
• /
• 제51권4호
• /
• pp.250-259
• /
• 2021

Objective: The aim of this study was to compare the differences in mandibular posterior anatomic limit (MPAL) distances stratified by vertical patterns in patients with skeletal Class III malocclusion by using cone-beam computed tomography (CBCT). Methods: CBCT images of 48 patients with skeletal Class III malocclusion (mean age, 22.8 ± 3.1 years) categorized according to the vertical patterns (hypodivergent, normodivergent, and hyperdivergent; n = 16 per group) were analyzed. While parallel to the posterior occlusal line, the shortest linear distances from the distal root of the mandibular second molar to the inner cortex of the mandibular body were measured at depths of 4, 6, and 8 mm from the cementoenamel junction. MPAL distances were compared between the three groups, and their correlations were analyzed. Results: The mean ages, sex distribution, asymmetry, and crowding in the three groups showed no significant differences. MPAL distance was significantly longer in male (3.8 ± 2.6 mm) than in female (1.8 ± 1.2 mm) at the 8-mm root level. At all root levels, MPAL distances were significantly different in the hypodivergent and hyperdivergent groups (p < 0.001) and between the normodivergent and hyperdivergent groups (p < 0.01). MPAL distances were the shortest in the hyperdivergent group. The mandibular plane angle highly correlated with MPAL distances at all root levels (p < 0.01). Conclusions: MPAL distances were the shortest in patients with hyperdivergent patterns and showed a decreasing tendency as the mandibular plane angle increased. MPAL distances were significantly shorter (~3.16 mm) at the 8-mm root level.

• 대한치과교정학회지
• /
• 제49권6호
• /
• pp.349-359
• /
• 2019

Objective: The aim of this study was to analyze three-dimensional (3D) changes in maxillary dentition in Class II malocclusion treatment using arch wire with continuous tip-back bends or compensating curve, together with intermaxillary elastics by superimposing 3D virtual models. Methods: The subjects were 20 patients (2 men and 18 women; mean age 20 years 7 months ${\pm}$ 3 years 9 months) with Class II malocclusion treated using $0.016{\times}0.022-inch$ multiloop edgewise arch wire with continuous tip-back bends or titanium molybdenum alloy ideal arch wire with compensating curve, together with intermaxillary elastics. Linear and angular measurements were performed to investigate maxillary teeth displacement by superimposing pre- and post-treatment 3D virtual models using Rapidform 2006 and analyzing the results using paired t-tests. Results: There were posterior displacement of maxillary teeth (p < 0.01) with distal crown tipping of canine, second premolar and first molar (p < 0.05), expansion of maxillary arch (p < 0.05) with buccoversion of second premolar and first molar (p < 0.01), and distal-in rotation of first molar (p < 0.01). Reduced angular difference between anterior and posterior occlusal planes (p < 0.001), with extrusion of anterior teeth (p < 0.05) and intrusion of second premolar and first molar (p < 0.001) was observed. Conclusions: Class II treatment using an arch wire with continuous tip-back bends or a compensating curve, together with intermaxillary elastics, could retract and expand maxillary dentition, and reduce occlusal curvature. These results will help clinicians in understanding the mechanism of this Class II treatment.

• 대한치과교정학회지
• /
• 제52권5호
• /
• pp.324-333
• /
• 2022

Objective: The aim of this study was 1) to investigate the prevalence and pattern of dental anomalies (DAs), 2) to compare DAs according to the type of malocclusion, and 3) to investigate the correlation between tooth impaction and other DAs in the Korean orthodontic population. Methods: A total of 3,240 orthodontic patients were classified as Class I, Class II, or Class III malocclusion groups. The presence and location of common DAs, including impaction, microdontia, agenesis, supernumerary tooth, transposition, and fusion, were identified by examining diagnostic records. Furthermore, samples were classified as Group 1 without impaction or Group 2 with impaction. The prevalence of other DAs concurrent with impaction was investigated and compared to Group 1. Results: Impaction was the most prevalent DA, followed by microdontia, agenesis, and supernumerary. Class I and Class III groups showed the same order of prevalence, but agenesis was more frequent than microdontia in the Class II group. The prevalence of the four DAs was lowest in the Class III group. Overall, 8.6% of patients were classified into Group 2. The incidence of DAs other than impaction and the prevalence of multiple concurrent DAs were significantly higher in Group 2. Impaction showed a significant relationship with supernumerary tooth, transposition, and fusion. Conclusions: The prevalence and pattern of DAs varied depending on the type of malocclusion. As there was a higher risk of other DAs in patients with impacted teeth, early detection of the impacted tooth and a detailed diagnosis of other possible DAs may be essential.

• 대한치과교정학회지
• /
• 제52권2호
• /
• pp.85-101
• /
• 2022

Objective: To classify facial asymmetry (FA) phenotypes in adult patients with skeletal Class III (C-III) malocclusion. Methods: A total of 120 C-III patients who underwent orthognathic surgery (OGS) and whose three-dimensional computed tomography images were taken one month prior to OGS were evaluated. Thirty hard tissue landmarks were identified. After measurement of 22 variables, including cant (°, mm), shift (mm), and yaw (°) of the maxilla, maxillary dentition (Max-dent), mandibular dentition, mandible, and mandibular border (Man-border) and differences in the frontal ramus angle (FRA, °) and ramus height (RH, mm), K-means cluster analysis was conducted using three variables (cant in the Max-dent [mm] and shift [mm] and yaw [°] in the Manborder). Statistical analyses were conducted to characterize the differences in the FA variables among the clusters. Results: The FA phenotypes were classified into five types: 1) non-asymmetry type (35.8%); 2) maxillary-cant type (14.2%; severe cant of the Max-dent, mild shift of the Man-border); 3) mandibular-shift and yaw type (16.7%; moderate shift and yaw of the Man-border, mild RH-difference); 4) complex type (9.2%; severe cant of the Max-dent, moderate cant, severe shift, and severe yaw of the Man-border, moderate differences in FRA and RH); and 5) maxillary reverse-cant type (24.2%; reverse-cant of the Max-dent). Strategic decompensation by pre-surgical orthodontic treatment and considerations for OGS planning were proposed according to the FA phenotypes. Conclusions: This FA phenotype classification may be an effective tool for differential diagnosis and surgical planning for Class III patients with FA.

• 대한치과교정학회지
• /
• 제30권2호
• /
• pp.159-174
• /
• 2000

III급 부정교합을 치료하기 위한 여러 치료 방법들이 소개되었고 치료 방법은 술자의 선호도와 경험, 그리고 치료 성공률과 같은 술자에 관한 것이 아니라 환자가 갖고 있는 문제에 따라 선택되는 것이 바람직하며 따라서 환자가 갖고 있는 문제를 정확히 파악하는 것이 중요하다. III급 부정교합의 구성요소에 대한 연구들이 보고된 바 있으나 그 결과는 인종과 연령에 따라 각기 다양하게 보고되고 있다. 이에 본 연구는 성장 변형 치로의 대부분이 행해지는 시기인 8-10세의 우리나라 성장기 아동을 대상으로 III급 부정교합의 본질을 나타내는 다양한 구성요소들을 알아보아 환자가 갖고 있는 문제를 파악함으로써 적절한 치료 방법의 선택에 도움을 주고자 III급 부정교합을 보이는 125명의 8-10세 환자들의 측모 두부방사선규격 사진을 이용하여 McNamara방법에 의해 4가지 수평요소와 1가지 수직요소를 계측한 결과 다음과 같은 결과를 얻었다. 1. III급 부정교합은 한가지의 임상적 실체가 아닌 악골과 치아의 다양한 상태의 조합으로 구성되어 있었다. 2. 상악골의 후방 위치가 III급 부정교합자들의 가장 흔한 특징이었다. 3. 상악 전치는 대부분 후방 위치하였다. 4. 하악 전치는 대부분 전방 위치하였다. 5. 하악골은 정상적 위치인 경우가 많으나 전돌과 후퇴도 있었다. 5. 수직적으로는 과도한 성잘 양상을 보이는 경우가 많았다. 이상의 결과로 우리나라 성장기 아동의 III급 부정교합에서는 수직적 성장 억제와 상악골의 수평적 성장 촉진에 대한 치료 기법들의 적용이 많은 경우에서 더욱 필요할 것으로 생각된다.