• 대한치과교정학회지
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• 제42권2호
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• pp.73-79
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• 2012

Objective: The purpose of this study was to investigate the effects of a newly developed rapid maxillary expansion screw-the memory screw-over 6 months. Methods: Five subjects, aged between 11.7 and 13.75 years, were enrolled in this study. All subjects underwent placement of a maxillary expansion appliance containing superelastic nickel-titanium open-coil springs in its screw bed. The parents of the patients and/or the patients themselves were instructed to activate the expansion screw by 2 quarter-turns 3 times a day (morning, midday, and evening; 6 quarter-turns a day). The mean expansion period was $7.52{\pm}1.04$ days. Dentoskeletal effects of the procedure, including dentoalveolar inclination, were evaluated. Measurements of all the parameters were repeated after 6 months of retention in order to check for relapse. Results: Sella-Nasion-A point (SNA) and Sella-Nasion/Gonion-Menton angles increased, and Sella-Nasion-B point (SNB) angle decreased in all the subjects during the expansion phase. However, they approximated to the initial values at the end of 6 months. On the other hand, the increments in maxillary apical base (Mxr-Mxl) and intermolar widths was quite stable. As expected, some amount of dentoalveolar tipping was observed. Conclusions: The newly developed memory expansion screw offers advantages of both rapid and slow expansion procedures. It widens the midpalatal suture and expands the maxilla with relatively lighter forces and within a short time. In addition, the resultant increments in the maxillary apical base and intermolar width remained quite stable even aft er 6 months of retention.

• 대한치과교정학회지
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• 제48권1호
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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.

• 대한치과교정학회지
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• 제50권5호
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• pp.304-313
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• 2020

Objective: The aim of this study was to evaluate the stability of bimaxillary surgery involving bilateral intraoral vertical ramus osteotomy performed with or without presurgical miniscrew-assisted rapid palatal expansion (MARPE) in adult patients with skeletal Class III malocclusion. Methods: A total of 40 adult patients with skeletal Class III malocclusion were retrospectively divided into two groups (n = 20 each) according to the use of MARPE for the correction of transverse maxillomandibular discrepancy during presurgical orthodontic treatment. Serial lateral cephalograms and dental casts were analyzed until 6 months after surgery. Results: Before presurgical orthodontic treatment, there was no significant differences in terms of sex and age between groups. However, the difference of approximately 3.1 mm in the maxillomandibular intermolar width was statistically significant (p < 0.001). Two days after surgery, the mandible had moved backward and upward without any significant intergroup difference. Six months after surgery, the maxillary intercanine (2.7 ± 2.1 mm), interpremolar (3.6 ± 2.4 mm), and intermolar (2.0 ± 1.3 mm) arch widths were significantly increased (p < 0.001) relative to the values before presurgical orthodontic treatment in the MARPE group; these widths were maintained or decreased in the control group. However, there was no significant difference in surgical changes and the postsurgical stability between the two groups. No significant correlations existed between the amount of maxillary expansion and postsurgical mandibular movement. Conclusions: MARPE is useful for stable and nonsurgical expansion of the maxilla in adult patients with skeletal Class III malocclusion who are scheduled for bimaxillary surgery.

• 대한치과교정학회지
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• 제45권2호
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• pp.74-81
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• 2015

Objective: The purposes of this study were 1) to classify lingual dental arch form types based on the lingual bracket points and 2) to provide a new lingual arch form template based on this classification for clinical application through the analysis of three-dimensional virtual models of normal occlusion sample. Methods: Maxillary and mandibular casts of 115 young adults with normal occlusion were scanned in their occluded positions and lingual bracket points were digitized on the virtual models by using Rapidform 2006 software. Sixty-eight cases (dataset 1) were used in K-means cluster analysis to classify arch forms with intercanine, interpremolar and intermolar widths and width/depth ratios as determinants. The best-fit curves of the mean arch forms were generated. The remaining cases (dataset 2) were mapped into the obtained clusters and a multivariate test was performed to assess the differences between the clusters. Results: Four-cluster classification demonstrated maximum inter-cluster distance. Wide, narrow, tapering, and ovoid types were described according to the intercanine and intermolar widths and their best-fit curves were depicted. No significant differences in arch depths existed among the clusters. Strong to moderate correlations were found between maxillary and mandibular arch widths. Conclusions: Lingual arch forms have been classified into 4 types based on their anterior and posterior dimensions. A template of the 4 arch forms has been depicted. Three-dimensional analysis of the lingual bracket points provides more accurate identification of arch form and, consequently, archwire selection.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제38권
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• pp.28.1-28.6
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• 2016

Backgrounds: Insufficient intermaxillary space is caused by non-restoration following tooth extraction in the past, and this involves eruption of the opposing teeth and changes of the arch structure. Such cases are difficult just by a simple prosthetic approach, and diversified treatment plans should be established. Among these, posterior maxillary segmental osteotomy (PMSO) is an efficient treatment option than extraction of opposing teeth as it surgically repositions multiple erupted teeth and alveolar bone. PMSO can preserve the natural teeth; therefore, it is being regarded as a treatment method which can improve insufficient intermaxillary space significantly. Case presentation: In this case report, the first patient received PMSO in order to place an implant in the mandibular edentulous space after decreased vertical dimension is restored, and the second patient received PMSO along with orthodontic treatment to obtain the intermaxillary space and balance the interarch molar width. Conclusion: PMSO is the treatment of choice when occlusion is compromised in the presence of decreased vertical dimension or arch length discrepancy.

• 대한치과교정학회지
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• 제17권1호
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• pp.33-45
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• 1987

This study was designed to examine relations between posture and size of the tongue and dentoalveolar pattern. The sample was consisted of three groups, the 34 subjects of Normal occlusion, the 31 subjects of Bimaxillary protrusion and the 31 subjects of Class III malocclusion. On the cephalograms, lengths, heights and areas of the tongue and intermaxillary space and on the study model, arch length, intercanine width, intermolar width and palatal height were measured. These data from measuring cephalograms and models were statistically analyzed. The results of the study were as follows; 1. Length of the tongue was the greatest in Bimaxillary protrusion and in order of Normal occlusion and Class III malocclusion. 2. Posture of the tongue was the lowest in Class III malocclusion and in order of Bimaxillary protrusion and Normal occlusion. 3. There were a tendency to be larger area of tongue and intermaxillary space in Class III malocclusion compared to Normal occlusion and Bimaxillary protrusion. 4. Size of the tongue and intermaxillary space showed low correlations with the dentoalveolar pattern.

• 대한치과교정학회지
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• 제14권1호
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• pp.115-125
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• 1984

A comparative study was undertaken to investigate the collapse of maxillary dental arch and palate in unilateral cleft lip and palate individuals. The material for this study consisted of 39 subjects with repaired unilateral cleft lip and palate (30 males, 9 females). The measurements of unilateral cleft lip and palate individuals were compared with the measurements of normal individuals (30 males, 30 females). All the subjects were in the mixed dentition stage and the mean age was almost the same. The following conclusions were obtained. 1. A large number of the maxillary dental arch of the unilateral cleft lip and palate individuals showed ${\Omega}$-shape, and the arch length was shorter than that of normal individuals. The intermolar width did not show significant difference between cleft group and group, but the intercanine width was mcuh smaller than that of normal individuals. 2. The palate of the unilateral cleft lip and palate subjects showed shorter and shallower form than that of normal subjects. 3. The palatal area of the unilateral cleft lip and palate subjects was smaller than that of normal subjects, and the cleft side area was much smaller than the opposing side area. 4. There was no significant sexual difference in measurements of maxillary dental arch and palate of the unilateral cleft lip and palate subjects.

• 대한치과교정학회지
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• 제41권4호
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• pp.288-296
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• 2011

Objective: The purposes of this study were to evaluate the relationship between the dental and basal arch forms; to analyze their differences in the tapered, ovoid, and square arch forms in normal occlusion by using three-dimensional (3D) virtual models; and to test the hypothesis that the overjet and maxillomandibular basal arch width difference have a significantly positive correlation. Methods: Seventy-seven normal occlusion plaster casts were examined by 3D scanning. Facial axis (FA) and WALA points were digitized using the Rapidform 2006 software. The dimensions of the dental and basal arches and the overjet were measured. The samples were classified into 3 groups according to arch forms: tapered (n = 20), ovoid (n = 20), and square (n = 37). Analysis of variance (ANOVA) was used to compare the dental and basal arch dimensions. The Pearson correlation coefficients between the intercanine as well as the intermolar widths at the FA and WALA points were calculated. Results: With regard to the basal arch dimensions, the tapered arch form showed a larger mandibular intermolar depth than the ovoid. Strong correlations were noted between the basal and dental intermolar widths in both the upper and lower arches (r = 0.83 and 0.85, respectively). Moderate correlation was found between the upper and lower intercanine widths (r = 0.65 and 0.48, respectively). Conclusions: The 3 dental arch form groups differed only in some dimensions of the skeletal arch. Moderate correlations were found between the basal and dental intercanine widths. These findings suggest that the basal arch may not be a principle factor in determining the dental arch form.

• 대한치과교정학회지
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• 제47권1호
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• pp.11-20
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• 2017

Objective: This randomized controlled trial aimed to compare the stability of mandibular arch orthodontic treatment outcomes between passive self-ligating and conventional systems during 6 months of retention. Methods: Forty-seven orthodontic patients with mild to moderate crowding malocclusions not requiring extraction were recruited based on inclusion criteria. Patients (mean age $21.58{\pm}2.94years$) were randomized into two groups to receive either passive self-ligating ($Damon^{(R)}$ 3MX, n = 23) or conventional system (Gemini MBT, n = 24) orthodontic treatment. Direct measurements of the final sample comprising 20 study models per group were performed using a digital caliper at the debonding stage, and 1 month, 3 months, and 6 months after debonding. Paired t-test, independent t-test, and non-parametric test were used for statistical analysis. Results: A significant increase (p < 0.01) in incisor irregularity was observed in both self-ligating and conventional system groups. A significant reduction (p < 0.01) in second interpremolar width was observed in both groups. Mandibular arch length decreased significantly (p = 0.001) in the conventional system group but not in the self-ligating system group. A similar pattern of stability was observed for intercanine width, first interpremolar width, intermolar width, and arch depth throughout the 6-month retention period after debonding. Comparison of incisor irregularity and arch dimension changes between self-ligating system and conventional system groups during the 6 months were non-significant. Conclusions: The stability of treatment outcomes for mild to moderate crowding malocclusions was similar between the self-ligating system and conventional system during the first 6 months of retention.

• 대한치과교정학회지
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• 제27권1호
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• pp.55-63
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• 1997

치열궁의 크기와 폭경 변화에 대한 연구가 사용된 장치 형태, 사용시기에따라, 그리고 사용 목적에 따라 다양한 연구가 활발히 이루어져 왔다. 또한 Quad-helix도 선학들에게 관심의 대상이었으며 Quad-helix의 안정성과 장치 사용 전, 후에 대한 효과도 연구가 이루어졌다. 그러나 장치 사용에 대한 장기적인 효과에 대한 연구가 미흡하여 본 논문은 이 장치를 사용하여 치료한 환자의 치료전,후 및 보정후의 치열궁 변화에 대한 연구를 시행하여 Quad-helix사용 전, 후 구치부의 적응 양상을 연구함으로써 임상에서 Quad-helix를 통한 치료를 시행할 때 이 장치사용에 따른 효과 및 예후에 대하여 효과를 이해함으로써 교정치료에 도움을 주고자 연구를 시행하여 다음과 같은 결과를 얻었다. 1. Quadhelix를 사용한 교정치료시 상악 제 1 소구치 와 제 1 대구치는 치료전과 치료후 및 보정후에서 교두간 폭경의 증가를 보였고 제 2 소구치에서는 치료후와 보정후간에 유의성있는 증가를 보였다. 2. 상악 제 1 소구치와 제 1 대구치의 치축은 치료전과 치료후 그리고 보정후에서 협측 경사도가 유의하게 증가를 보였으며, 상악 제 2 소구치는 치료전과 치료후 및 치료전과 보정후 비교에서 설측 경사도가 유의하게 증가를 보였다. 3. 최대 풍융부 항목에서 상악 제 1, 2소구치는 치료전과 치료후의 비교에서 유의한 증가를, 제 1 대구치에서는 치료전,후, 및 보정후에 유의한 증가를 보였다. 4. 상악 제 1 대구치의 설면구 폭경은 치료전,후 및 보정기간을 통하여 유의한 증가를 보였고,구개 높이는 치료전과 치료후 비교시 유의한 증가를 보였다. 5. 확장시킨 상악 치열궁은 회귀현상을 보이지 않고 안정적으로 유지되었다.