• 대한치과교정학회지
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• 제54권2호
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• pp.79-88
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• 2024

Objective: Alveolar bone loss is a common adverse effect of intrusion treatment. Mandibular incisors are prone to dehiscence and fenestrations as they suffer from thinner alveolar bone thickness. Methods: Thirty skeletal class II patients treated with mandibular intrusion arch therapy were included in this study. Lateral cephalograms and cone-beam computed tomography images were taken before treatment (T1) and immediately after intrusion arch removal (T2) to evaluate the tooth displacement and the alveolar bone changes. Pearson's and Spearman's correlation was used to identify risk factors of alveolar bone loss during the intrusion treatment. Results: Deep overbite was successfully corrected (P < 0.05), accompanied by mandibular incisor proclination (P < 0.05). There were no statistically significant change in the true incisor intrusion (P > 0.05). The labial and lingual vertical alveolar bone levels showed a significant decrease (P < 0.05). The alveolar bone is thinning in the labial crestal area and lingual apical area (P < 0.05); accompanied by thickening in the labial apical area (P < 0.05). Proclined incisors, non-extraction treatment, and increased A point-nasion-B point (ANB) degree were positively correlated with alveolar bone loss. Conclusions: While the mandibular intrusion arch effectively corrected the deep overbite, it did cause some unwanted incisor labial tipping/flaring. During the intrusion treatment, the alveolar bone underwent corresponding changes, which was thinning in the labial crestal area and thickening in the labial apical area vice versa. And increased axis change of incisors, non-extraction treatment, and increased ANB were identified as risk factors for alveolar bone loss in patients with mandibular intrusion therapy.

• 대한치과의사협회지
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• 제38권4호통권371호
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• pp.369-377
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• 2000

• 대한치과의사협회지
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• 제21권12호통권175호
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• pp.985-990
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• 1983

320 cephalometric roentgenograms of 25 boys and 15 girls which was longitudinally taken from the age 6.5 to 13.5 have been analyzed to access the angular growth changes of the mandible. The statistical analysis of the results allowed the following conclusions. 1. Gonial angle was reduced with ageing. 2. Chin angle was reduced with ageing. 3. Occlusal plane to mandibular plane angle was relatively stable. 4. Lower incisor to occlusal plane angle was reduced and showed the greatest variability.

• 대한치과교정학회지
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• 제50권2호
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• pp.120-128
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• 2020

Objective: The aims of the present study were to evaluate the changes in the maximum lip-closing force (MLF) after orthodontic treatment with or without premolar extractions and verify the correlation of these changes with dentoskeletal changes. Methods: In total, 17 women who underwent nonextraction orthodontic treatment and 15 women who underwent orthodontic treatment with extraction of all four first premolars were included in this retrospective study. For all patients, lateral cephalograms and dental models were measured before (T0) and after (T1) treatment. In addition, MLF was measured at both time points using the Lip De Cum LDC-110R^® device. Statistical analyses were performed to evaluate changes in clinical variables and MLF and their correlations. Results: Both groups showed similar skeletal patterns, although the extraction group showed greater proclination of the maxillary and mandibular incisors and lip protrusion compared to the nonextraction group at T0. MLF at T0 was comparable between the two groups. The reduction in the arch width and depth and incisor retroclination from T0 to T1 were more pronounced in the extraction group than in the nonextraction group. MLF in the extraction group significantly increased during the treatment period, and this increase was significantly greater than that in the nonextraction group. The increase in MLF was found to be correlated with the increase in the interincisal angle and decrease in the intermolar width, arch depth, and incisor-mandibular plane angle. Conclusions: This study suggests that MLF increases to a greater extent during extraction orthodontic treatment than during nonextraction orthodontic treatment.

• 대한치과교정학회지
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• 제48권1호
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• pp.11-22
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• 2018

Objective: The aim of this study was to determine cephalometric factors that help predict favorable soft-tissue profile outcomes following treatment with the Class II Twin-block appliance. Methods: Pre- and post-treatment lateral cephalograms of 45 patients treated with the Class II Twin-block appliance were retrospectively analyzed. Profile silhouettes were drawn from the cephalograms and evaluated by three orthodontists in order to determine the extent of improvement. Samples were divided into a favorable group (upper 30% of visual analogue scale [VAS] scores, n = 14) and an unfavorable group (lower 30% of VAS scores, n = 14). Skeletal and soft-tissue measurements were performed on the cephalograms and an intergroup comparison was conducted. Results: An independent t-test revealed that the following pre-treatment values were lower in the favorable group compared to the unfavorable group: lower incisor to mandibular plane angle, lower incisor to pogonion distance, point A-nasion-point B angle, sella-nasion line (SN) to maxillary plane angle, SN to mandibular plane angle, gonial angle, and symphysis inclination. The favorable group had a larger incisor inclination to occlusal plane. Moreover, the favorable group showed larger post-treatment changes in gonial angle, B point projection, and pogonion projection than did the unfavorable group. Conclusions: Class II malocclusion patients with a low divergent skeletal pattern and reduced lower incisor protrusions are likely to show more improvement in soft-tissue profile outcomes following Class II Twin-block treatment.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권5호
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• pp.311-319
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• 2012

Purpose: The aim of this study is to evaluate the vertical changes of the lip and perioral soft tissue, following orthognathic surgery in skeletal class III patients by a cephalometric analysis of a cone beam computed tomography (CBCT). Methods: A total of 20 skeletal class III patients, who had bimaxillary surgery with Le Fort 1 osteotomy and bilateral sagittal split ramus osteotomy, were included in this study. The surgical plan for maxilla was posterosuperior impaction with the anterior nasal spine, as the rotation center. Further, the surgical plan for mandible was also posterosuperior movement. The soft tissue changes between lateral cephalogram and CBCT were compared. And the correlations between independent variables and dependent variables were evaluated. Results: There were no significant differences of the soft tissues changes between lateral cephalogram and CBCT. Upper lip philtrum length (SnLs), nasolabial angle increased and upper lip vermilion length (LsStms), lower lip length (StmiB'), lower lip vermilion length (StmiLi), lower lip philtrum length (LiB') and soft tissue lower facial height (SnMe') decreased after surgery. Change of SnLs (${\Delta}$SnLs) was influenced by vertical change of menton (${\Delta}$MeV), and change of LsStms (${\Delta}$LsStms) was influenced by upper lip thickness (ULT). Change of StmiLi' (${\Delta}$StmiLi') were influenced by preoperative overjet. Change of StmiB' (${\Delta}$StmiB') were influenced by preoperative overjet, vertical change of lower incisor (${\Delta}$L1V) and horizontal change of posterior nasal spine (${\Delta}$PNSH). Change of LiB' (${\Delta}$LiB') was influenced by ${\Delta}$L1V and ${\Delta}$PNSH. Change of SnMe' (${\Delta}$SnMe') was influenced by ${\Delta}$MeV, horizontal change of upper incisor (${\Delta}$U1H) and horizontal change of lower incisor (${\Delta}$L1H). ${\Delta}$Nasolabial angle was influenced by change of ULT (${\Delta}$ULT). Conclusion: Both soft tissues and hard tissues can be evaluated by CBCT. Posterosuperior rotation of maxillomandibular complex resulted in increase of upper lip philtrum length and nasolabial angle, while the upper lip vermilion length, lower lip philtrum length, lower lip vermilion length, and soft tissue lower facial height showed a decrease.

• 대한치과기공학회지
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• 제25권1호
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• pp.95-102
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• 2003

The purpose of this study was to show occlusion on the simple hinge articulator optionally mounted. Modelling of upper-lower jaw and simple hinge articulator were developed. This modelling of upper-lower jaw inserting wax bite was mounted imaginary on the modelling of simple hinge articulator by use of the computer simulation. From changes of THA(transverse horizontal axis)-incisor distance, Balkwill angle and THA deviation, eight types were mounted respectively. After removal of wax bite, upper-lower jaw position changing were compared with centric jaw relation. The results were as follows: 1. The change of THA-incisor distance had influence on mostly a vertical shift of upper jaw. 2. The change of Balkwill angle had influence on mostly a horizontal shift of upper jaw. 3. Inferior type in the THA deviations was the least shift of upper jaw. The above results suggest that the simple hinge articulator optionally mounted effect a shift of upper jaw.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제36권5호
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• pp.375-379
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• 2010

Introduction: In the management of dentofacial deformities, variable movement of the maxilla can be made possible by a Le Fort I osteotomy. Posterior impaction of the maxilla necessary for rotation of the maxillomandibular complex enhances the functions and esthetic results. In cases of posterior impaction of the maxilla, an increase in the figure of the occlusal plane angle and incisor inclination can occur. This study reports the relationship between the amount of posterior impaction and the change in the occlusal plane angle and incisor inclination in a Le Fort I osteotomy by preoperative and postoperative lateral cephalograms. Materials and Methods: Twenty patients who had undergone orthognathic surgery in Dong-A University Medical Center participated in this study. Lateral cephalometrics, within 3 weeks prior to surgery and 3 days after surgery, were used for analysis. Pre and postoperative measurements of the occlusal plane angle and incisal inclination based on the Frankfort horizontal (FH) plane were performed. X and Y were defined as the amount of vertical change in the upper incisor tip and the amount of vertical change in the upper first molar mesial cup tip through the operation. The amount of final posterior maxillary impaction was determined by subtracting Y from X, which is the difference in vertical height. According to the amount of posterior maxillary impaction, the change in the occlusal plane angle and incisal inclination was measured. Results: The average posterior maxillary impaction was 2.91 mm and the average change in the occlusal plane angle and incisal inclination was $6.54^{\circ}$after surgery. As a result, each mm of posterior maxillary impaction changed the occlusal plane angle and incisal inclination by $2.25^{\circ}$. Statistically, there was high significance. Two cases were observed: one with the same amount of posterior maxillary impaction performed on both the right and left showing $2.20^{\circ}$, and the other with a different amount of posterior maxillary impaction performed showing $2.35^{\circ}$. In this case, there was no significance difference between the two cases. Conclusion: Each mm of posterior maxillary impaction changes the occlusal plane angle and incisal inclination by an average of $2.25^{\circ}$. In posterior maxillary impaction, there was no significant difference in the amount of change in the occlusal plane angle and incisal inclination regardless of whether there was an equal amount of posterior maxillary impaction on both sides. This study is expected to help in the presurgical orthodontic preparation and presurgical treatment planning.

• 대한치과교정학회지
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• 제26권2호
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• pp.219-232
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• 1996

본 연구의 목적은 II급 1류 부정교합에서 bionator를 사용한 환자의 치료 전후 두부방사선계측사진에 유한요소법을 적용하여 나타난 변화를 각 요소별로 나타내며, 이러한 변화와 치료에 영향을 미치는 인자들 간의 연관성을 살펴보는데 있다. 앵글 II급 1류 부정 교합을 가진 73명을 치료결과가 양호한 군(1군)과 치료결과가 불량한 군(2군)으로 나눈 후 각각의 치료효과에 대한 유한요소분석을 실시한 후 성별간, 치료결과군간 및 치료시작시기와의 유의성을 검증하였으며 (SAS ANOVA, p<0.05), 치료기간과의 상관관계를 살펴보았다. 또한 치료결과가 다르게 나오는 이유를 보고자 두개저의 길이(Ba-N)를 기준으로 1군에서 2군으로 유한요소분석을 실시하여 다음의 결과를 얻을 수 있었다. 1. 치료효과와 성별간, 치료결과군간 사이에 유의한 차이가 없었다 (p>0.05). 2. 치료시작 연령과 치료효과 사이에 유의한 차이가 없었다(p>0.05). 3. 치료효과와 치료기간 사이에서는 상악체, 상악절치, 하악절치, 전안면, 전상안면, 전하안면, 하악지 등을 대표하는 유한요소에서 유의한 차이(p<0.05)가 있었으나, 상관관계는 높지 않았다. 4. 유한요소 분석 결과 골격보다는 치아를 대표하는 요소의 변화가 더 컸다. 특히 상악절치의 위치, 하악절치의 위치, overbite 등을 나타내는 요소의 변화를 뚜렷하게 관찰할 수 있었다. 5. 치료결과가 다르게 나타나는 이유를 두개저 (Ba-N)의 길이를 중심으로 유한요소로 분석 한 결과 두군사이에 골격 및 치아의 위치에서 상당한 차이가 있음을 관찰할 수 있었다. 치료결과가 나쁜 군에서 상악의 후하방 회전, 하악의 후방위치, 상악전치의 상대적인 설측경사, 하악절치의 상대적인 순측경사 등을 관찰할 수 있었다.

• 대한치과교정학회지
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• 제27권1호
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• pp.21-33
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• 1997

부산대학교병원 교정과에서 골격성 III급 부정 교합으로 진단되어 술전교정치료를 받고 악안면구강외과에서 악교정 수술을 받은 편악 수술군 18명과 양악 수술군 24명, 총 42명을 대상으로 초진, 수술 전, 수술 직후 및 수술 후 6개월 이상 경과 후에 채득한 측모두부방사선규격사진을 이용하여 분석하였다. 편악 수술군과 양악 수술군에서 치료과정에 따른 변화를 조사하여 악교정수술후 하악의 안정성에 영향을 미치는 요소를 알아보고자 분산분석을 기초로 하여 단계적 다중 희귀 분석을 시행하여 다음과 같은 결과를 얻었다. 1. 편악 수술군에서 수술에 의한 이동량, 하악전치 고경의 변화와 술전교정치료에 의한 하악평면각의 변화 및 하악전치의 경사도 변화가 악교정 수술후 하악의 안정성을 잘 설명하였고 결정계수는 0.84이었다. 2. 양악 수술군에서 수술에 의한 하악의 후방 이동량이 악교정 수술후 하악의 안정성을 설명하였고 결정계수는 0.28이었다.