• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.23.1-23.10
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• 2019

The choice of surgical technique in orthognathic surgery is based primarily on the surgical treatment objectives (STO), which is a fundamental component of the orthognathic treatment process. In the conventional orthodontics-first approach, presurgical planning can be performed twice, during the preorthodontic (initial STO) and presurgical phases (final STO). Recently, a surgery-first orthognathic approach (SFA) without presurgical orthodontic treatment has been introduced and combined initial and final STO at the same time. In contrast to the conventional surgical-orthodontic treatment protocol that includes preoperative orthodontics for dental decompensations to maximize stable postoperative occlusion, the SFA potentially shortens the treatment period and minimizes esthetic concerns during the decompensation period because skeletal problems are corrected from the beginning. The indications for the SFA have been proposed in the literature, but no consensus exists. Moreover, because dental occlusion of the pre-orthodontic arches cannot be used as a guide for establishing the surgical treatment plan, there are fundamental limitations in accurate prediction of postsurgical results in the SFA. Recently, the concepts of postsurgical orthodontic treatment are continuously changing and evolving to overcome this inherent limitation of the SFA. The elimination of presurgical orthodontics can change the paradigm of orthognathic surgery but still requires cautious case selection and thorough discussion and collaboration between orthodontists and surgeons regarding the goals and postoperative management of the orthognathic procedure.

• The korean journal of orthodontics
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• v.17 no.1
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• pp.73-83
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• 1987

The purpose of this longitudinal study was to examine the growth changes of mandibular symphysis and lower incisors with age. The material was 294 lateral cephalometric radiographs taken longitudinally from 6 to 13 year old children, who were not teated orthodontically. The following conclusions seem to be warranted. 1. The sex difference of the measurements of mandibular symphysis and lower incisors were not statistic ally significant. 2. There were growth increments (2.69mm in boys and 2.08mm in girls) in the total thickness of mandibular symphysis. 3. There were a great change and individual variations on the curvature of anterior border of mandibular symphysis. 4. The chin angle had a tendency to decrease progressively in both sexes. 5. There were growth increments (8.23mm in boys and 7.40mm in girls) in the anterior dental height. 6. The lower anterior teeth tended to incline labially with age.

• The korean journal of orthodontics
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• v.23 no.1 s.40
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• pp.123-136
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• 1993

The purpose of this report is to present the successful improvement of occlusal relationship and facial esthetics in class II division 1 malocclusion with severe labioversion of upper anterior teeth and severe overjet, and in class II malocclusion with infraversion of bilateral maxillary canines by MEAW mechanics, which enables us to get effective distal on mass movement of maxillary dentition, with upper second molar extraction. After treatment, there were natural contact points at canine and premolar regions, normal occlusal relation-ship and treatment results, satisfied the gnathologic concept, in this 2 cases. Compared with the routine treatment with premolar extraction, the treatment time and patients' discomfort were reduced. And the MEAW mechanics, which enables us to get effective distal on mass movement of maxillary dentition, resulted in reduction of the treatment time and getting the good treatment results. Consequently, the majot concerns in orthodontic treatment are appropriate diagnosis and treatment plan, so, the application of second molar extraction with appropriate case analysis and diagnosis is very helpful to orthodontic treatment.

• The korean journal of orthodontics
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• v.25 no.5 s.52
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• pp.627-634
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• 1995

The purpose of this study to analyze characteristics of soft tissue profile in Korean young adults. The sample consisted of 50 young adults (25 males and B females) who had pleasing and normal occlusion. Soft tissue analysis (facial convexity angle, nasolabial angle, H-angle, Z-angle, E-line to upper lip, lower lip, Sn-pog' to upper lip, lower lip) was performed on lateral cephlograms. Mem and standard deviation was obtained. When compared by other studies, mean profile of this sample was relatively straighter and both the upper and lower lips was more protrusive.

• The korean journal of orthodontics
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• v.41 no.2
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• pp.127-137
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• 2011

Objective: The aim of the study was to compare the opening and protrusive mandibular movements between Class I and Class II malocclusions in healthy adolescents by clinical and axiographic evaluations. Methods: Mechanical axiography was performed on non-orthodontically treated, temporomandibular disorder (TMD)-free adolescents (12 - 16 years) with Class I (n = 38, 16 boys, 22 girls) or Class II (n = 40, 19 boys, 21 girls) malocclusion. Opening and protrusive movements were measured clinically and axiographically. Intergroup comparisons were evaluated by t-tests. Results: In opening movement, the maximum clinical opening capacity was significantly different (p ${\leq}$ 0.05) between the groups. In protrusive movement, the Class II group had significantly greater maximum clinical protrusion (p < 0.001) and maximum axiographic protrusive length (p < 0.01) than the Class I group. No significant difference in the other opening and protrusive axiographic measurements was observed. Conclusions: TMD-free adolescents with Class II malocclusion have increased protrusive capacity compared with TMD-free adolescents with Class I malocclusion; however, the detected differences could be normal variations during adolescence.

• The korean journal of orthodontics
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• v.42 no.5
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• pp.263-269
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• 2012

Objective: To evaluate the antimicrobial effect of different frequencies of brushing with fluoride toothpaste on the levels of salivary mutans streptococci and lactobacilli in children undergoing fixed orthodontic treatment. Methods: The study included 22 patients scheduled for fixed orthodontic therapy distributed between 2 groups with different hygiene regimes. All the subjects received identical braces, bands, and brackets bonded with the same material. Stimulated saliva samples were obtained before placement of the appliance and at 6, 12, and 18 weeks during the therapy. Saliva samples were cultured on selective microbial agar for the detection of microorganisms. Results: Salivary mutans streptococci were significantly suppressed throughout the experimental period in the group that brushed 4 times a day as compared to the group that brushed twice a day. Salivary lactobacilli were not significantly affected by the frequency of brushing with 0.32% sodium fluoride (NaF) toothpaste. Conclusions: The use of 0.32% NaF-containing toothpaste more than 3 times a day has effective antimicrobial activity on mutans streptococci but not lactobacilli in the saliva of children with fixed orthodontic appliances.

• The korean journal of orthodontics
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• v.42 no.4
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• pp.169-181
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• 2012

Objective: The purpose of this study was to develop superimposition method on the lower arch using 3-dimensional (3D) cone beam computed tomography (CBCT) images and orthodontic 3D digital modeling. Methods: Integrated 3D CBCT images were acquired by substituting the dental portion of 3D CBCT images with precise dental images of an orthodontic 3D digital model. Images were acquired before and after treatment. For the superimposition, 2 superimposition methods were designed. Surface superimposition was based on the basal bone structure of the mandible by surface-to-surface matching (best-fit method). Plane superimposition was based on anatomical structures (mental and lingual foramen). For the evaluation, 10 landmarks including teeth and anatomic structures were assigned, and 30 times of superimpositions and measurements were performed to determine the more reproducible and reliable method. Results: All landmarks demonstrated that the surface superimposition method produced relatively more consistent coordinate values. The mean distances of measured landmarks values from the means were statistically significantly lower with the surface superimpositions method. Conclusions: Between the 2 superimposition methods designed for the evaluation of 3D changes in the lower arch, surface superimposition was the simpler, more reproducible, reliable method.

• The korean journal of orthodontics
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• v.42 no.1
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• pp.11-16
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• 2012

Objective: This study aimed to evaluate the mean age of menarche, its secular trend in Korean women, and the relationship between malocclusion and the rate of skeletal maturation, as defined by menarcheal age. Methods: We retrospectively collected data on menarcheal age from 931 Korean women born during 1961 - 1997. Subjects were divided by the malocclusion type and birth-year decade into 3 and 4 groups, respectively. The mean menarcheal age for each group was determined, and one-way ANOVA was performed for intergroup comparison (p = 0.05). Two-way ANOVA was also performed to compare all the 12 subgroups (p = 0.05). Results: The mean age of menarche was 12.82 years for Korean women born during 1961 - 1997. A distinct downward secular trend of menarcheal age was noticed (p < 0.05). For the birth-year decade 1961 - 1970, the Class III malocclusion group showed earlier onset of menarche than the other malocclusion groups (p < 0.05), but the other birth-year groups did not show any significant difference in the type of malocclusion (p > 0.05). Conclusions: A positive secular trend towards earlier menarche exists among Korean women. Malocclusion does not show any significant relationship with the rate of skeletal maturation, as defined by menarcheal age.

• The korean journal of orthodontics
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• v.42 no.1
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• pp.4-10
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• 2012

Objective: To determine the effect of surface anodization on the interfacial strength between an orthodontic microimplant (MI) and the rabbit tibial bone, particularly in the initial phase aft er placement. Methods: A total of 36 MIs were driven into the tibias of 3 mature rabbits by using the self-drilling method and then removed aft er 6 weeks. Half the MIs were as-machined (n = 18; machined group), while the remaining had anodized surfaces (n = 18; anodized group). The peak insertion torque (PIT) and the peak removal torque (PRT) values were measured for the 2 groups of MIs. These values were then used to calculate the interfacial shear strength between the MI and cortical bone. Results: There were no statistical differences in terms of PIT between the 2 groups. However, mean PRT was significantly greater for the anodized implants ($3.79{\pm}1.39$ Ncm) than for the machined ones ($2.05{\pm}1.07$ Ncm) (p < 0.01). The interfacial strengths, converted from PRT, were calculated at 10.6 MPa and 5.74 MPa for the anodized and machined group implants, respectively. Conclusions: Anodization of orthodontic MIs may enhance their early-phase retention capability, thereby ensuring a more reliable source of absolute anchorage.

• The Journal of the Korean dental association
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• v.51 no.6
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• pp.330-336
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• 2013

Considering the high prevalence, transverse control in adult patients presenting relatively narrow maxillary width is a challenging issue. This study compared the pattern of arch expansion induced by either miniscrew-assisted rapid palatal expander (MARPE) or continuous archwire engaged on self-ligating brackets. Age-matched adults groups(N=15 each) were treated with respective appliance. In both groups, all intercanine, interpremolar, and intermolar widths increased, and significantly greater change was noted in the intermolar region. Buccal tipping was minimal in both groups. Subsequent arch length increase, lingual tipping of incisors and distal tipping of molars were also found in both groups. According to the results, it can be concluded that the MARPE induced generally more arch expansion, particularly in the intermolar width, indicating that the adults showing buccal crossbite of the molars may have to undergo expansion via MARPE prior to arch alignment using continuous archwire.