• 대한치과교정학회지
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• 제46권4호
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• pp.189-198
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• 2016

Objective: The purpose of this study was to analyze stress distributions in the roots, periodontal ligaments (PDLs), and bones around cylindrical and tapered miniscrews inserted at different angles using a finite element analysis. Methods: We created a three-dimensional (3D) maxilla model of a dentition with extracted first premolars and used 2 types of miniscrews (tapered and cylindrical) with 1.45-mm diameters and 8-mm lengths. The miniscrews were inserted at $30^{\circ}$, $60^{\circ}$, and $90^{\circ}$ angles with respect to the bone surface. A simulated horizontal orthodontic force of 2 N was applied to the miniscrew heads. Then, the stress distributions, magnitudes during miniscrew placement, and force applications were analyzed with a 3D finite element analysis. Results: Stresses were primarily absorbed by cortical bone. Moreover, very little stress was transmitted to the roots, PDLs, and cancellous bone. During cylindrical miniscrew insertion, the maximum von Mises stress increased as insertion angle decreased. Tapered miniscrews exhibited greater maximum von Mises stress than cylindrical miniscrews. During force application, maximum von Mises stresses increased in both groups as insertion angles decreased. Conclusions: For both cylindrical and tapered miniscrew designs, placement as perpendicular to the bone surface as possible is recommended to reduce stress in the surrounding bone.

• 대한치과교정학회:학술대회논문집
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• 대한치과교정학회 2003년도 제36회 학술대회
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• pp.32.1-32.1
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• 2003

• Maxillofacial Plastic and Reconstructive Surgery
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• 제30권4호
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• pp.345-352
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• 2008

Purpose: This study was performed to evaluate the stress distribution in the bone and the displacement distribution of the miniscrew under orthopedic force with two different types of miniplate design as skeletal anchorage for orthopedic treatment. Materials and methods: Finite element models were made for 6-hole miniplate (0.8mm in thickness), which were designed in two different shapes-one is curvilinear shaped (C plate, Jeil Medical Co., Korea) and another, Y shaped (Y plate), fixed with 3 pieces of miniscrew 2mm-diameter and 6mm-long respectively. A traction force of 4 N was applied in $0^{\circ}$, $30^{\circ}$ and $60^{\circ}$ to imaginary axis connecting two unfixed distalmost holes of the miniplate. Results: The maximum von Mises stress in the bone was much greater in the cortical portion rather than in the cancellous portion. C plate showed greater maximum von Mises stress in the cortical bone than Y plate. The maximum displacement of the miniscrew was greater in C plate than Y plate. The more increased the angle of the applied orthopedic force, the greater maximum von Mises stress in the bone and maximum displacement of the miniscrew. It was observed that in C plate, the von Mises stress in the bone and displacement of the miniscrew were distributed around the distalmost screw-fixed area. Conclusions: The results suggest that Y plate should have the advantage over C plate and in the placement of the miniplate, its imaginary axis should be placed as parallel as possible to the direction of orthopedic force to obtain its primary stability.

• 대한치과교정학회지
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• 제46권1호
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• pp.55-61
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• 2016

Skeletal anchorage-assisted upper molar distalization has become one of the standard treatment modalities for the correction of Class II malocclusion. The purpose of this study was to analyze maxillary molar movement patterns according to appliance design, with the simultaneous use of buccal fixed orthodontic appliances. The authors devised two distinct types of midpalatal miniscrew-assisted maxillary molar distalizers, a lingual arch type and a pendulum type. Fourteen patients treated with one of the two types of distalizers were enrolled in the study, and the patterns of tooth movement associated with each type were compared. Pre- and post-treatment lateral cephalograms were analyzed. The lingual arch type was associated with relatively bodily upper molar distalization, while the pendulum type was associated with distal tipping with intrusion of the upper molar. Clinicians should be aware of the expected tooth movement associated with each appliance design. Further well designed studies with larger sample sizes are required.

• 대한소아치과학회지
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• 제38권3호
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• pp.250-259
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• 2011

본 연구의 목적은 소아 청소년의 얇은 피질골에서 안정성을 가지는 미니스크류 디자인을 제시하고자 하는 것이다. 직경, 길이, 몸체모양을 달리한 교정용 미니스크류를 피질골의 두께를 달리한 두 종류의 인조골 시편에 식립하여 최대 식립 토크, 최대 제거 토크 및 측방 변위 토크를 측정하였다. 연구결과 피질골의 두께 및 미니스크류의 직경, 길이, 몸체모양은 모두 최대 식립 토크, 최대 제거 토크, 측방 변위 토크에 유의한 영향을 미쳤다. 피질골의 두께가 가장 중요한 요소로 나타났으며 원추형이 원통형보다 초기 고정력이 우수하고, 직경이 증가할수록 역학적 고정력 확보에 유리하였다. 길이의 증가는 다른 요소에 비해 초기 고정력 확보에 미치는 영향이 크지 않으나 6 mm와 8 mm는 고정력 확보에 통계적으로 유의한 차이가 있었다(p<0.05). 피질골이 얇은 소아 청소년의 골에서 미니스크류의 안정성은 원추형, 직경 1.8 mm가 유리하며, 길이도 6 mm 보다는 8 mm가 유리하다.

• 대한치과교정학회지
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• 제46권2호
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• pp.111-126
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• 2016

Objective: To systematically review previous studies and to assess, via a subgroup meta-analysis, the combined odds ratio (OR) of prognostic factors affecting the success of miniscrew implants (MIs) inserted into the buccal posterior region. Methods: Three electronic searches that were limited to articles on clinical human studies using MIs that were published in English prior to March 2015 were conducted. The outcome measure was the success of MIs. Patient factors included age, sex, and jaw of insertion (maxilla vs. mandible), while the MI factors included length and diameter. A meta-analysis was performed on 17 individual studies. The quality of each study was assessed for non-randomized studies and quantified using the Newcastle-Ottawa Scale. The meta-analysis outcome was a combined OR. Subgroup and sensitivity analyses based on the study design, study quality, and sample size of miniscrews implanted were performed. Results: Significantly higher success rates were revealed for MIs inserted in the maxilla, for patients ${\geq}20$ years of age, and for long MIs (${\geq}8mm$) and MIs with a large diameter (> 1.4 mm). All subgroups acquired homogeneity, and the combined OR of the prospective studies (OR, 3.67; 95% confidence interval [CI], 2.10-6.44) was significantly higher in the maxilla than that in the retrospective studies (OR, 2.10; 95% CI, 1.60-2.74). Conclusions: When a treatment plan is made, these risk factors, i.e. jaw of insertion, age, MI length, and MI diameter, should be taken into account, while sex is not critical to the success of MIs.

• 대한치과교정학회지
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• 제52권3호
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• pp.182-200
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• 2022

Objective: This study aims to examine the effectiveness of miniscrew assisted rapid palatal expansion (MARPE) treatment in late adolescents and adult patients using cone-beam computed tomography (CBCT). Methods: Literature search was conducted in five electronic databases (PubMed, Embase, Scopus, Web of Science, and Cochrane Library) based on the PICOS keyword design focusing on MARPE. Out of the 18 CBCT screened outcomes, only nine parameters were sufficient for the quantitative meta-analysis. The parameters were classified into three main groups: 1) skeletal changes, 2) alveolar change, and 3) dental changes. Heterogeneity test, estimation of pooled means, publication bias, sensitivity analysis and risk of bias assessment were also performed. Results: Upon database searching, only 14 full-text articles were qualified from the 364 obtained results. Heterogeneity test indicated the use of the random-effects model. The pooled mean estimate were as follows: 1) Skeletal expansion: zygomatic width, 2.39 mm; nasal width, 2.68 mm; jugular width, 3.12 mm; and midpalatal suture at the posterior nasal spine and anterior nasal spine, 3.34 mm and 4.56 mm, respectively; 2) Alveolar molar width expansion, 4.80 mm; and 3) Dental expansion: inter-canine width, 3.96 mm; inter-premolar width, 4.99 mm and inter-molar width, 5.99 mm. The percentage of expansion demonstrated a skeletal expansion (PNS) of 55.76%, alveolar molar width expansion of 24.37% and dental expansion of 19.87%. Conclusions: In the coronal view, the skeletal and dental expansion created by MARPE was of the pyramidal pattern. MARPE could successfully expand the constricted maxilla in late adolescents and adult patients.

• 대한치과교정학회지
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• 제34권5호
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• pp.458-464
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• 2004

교정치료에 있어서 고정원의 조절은 매우 중요한 요소이며, 상악에서 특히 그러하다. 이를 얻기 위해 많은 노력을 해 왔으나 대부분이 환자의 협조에 대한 의존이 필수적이었기 때문에 고정원 보강에 대하여 확신할 수 없었다. 하지만 최근 skeletal anchorage를 이용하여 환자의 협조를 최소화하면서도 보다 효과적으로 고정원 보강을 할 수 있는 방법이 시행되고 있다. 또한 과거의 골 융합성 임프란트와 달리 미니 스크류는 구강 내의 어느 부위에나 식립할 수 있을 정도로 식립 부위의 제한성이 적다는 장점이 있다. 저자는 titanium miniscrew를 구개 정중부의 약간 측방에 식립하고, indirect active P.S.A.(Palatal skeletal anchorage)를 이용하여 치료한 결과 상악 구치부에서의 고정원 보강을 얻을 수가 있었다. 이 치료 결과로 보아 PSA는 상악 구치부의 고정원 보강 역할을 할 수 있을 것으로 생각되며. 또한 transpalatal arch system의 다양한 design을 응용한다면 효율적인 치아 이동을 하는데 많은 도움이 될 것으로 생각된다.

• 대한치과교정학회지
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• 제41권4호
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• pp.297-306
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• 2011

경미한 III급 부정교합의 비발치 치료는 하악 치열의 원심이동과 상악 치열의 근심이동을 통하여 절충 치료를 하게 된다. 지금까지 하악 구치의 원심경사 및 후방이동을 시키기 위해서 다양한 치료 방법이 소개되어 왔다. 골성 고정원을 이용한 치료는 총생이 심한 경우와 같이 하악치열의 후방이동이 요구될 때 적용되는데 환자의 협조도와 무관하게 사용할 수 있지만, 하악 치열의 후방 이동 시 치근 접촉가능성이 있으며 골성 고정원의 탈락 가능성을 배제할 수 없다. Multiloop edgewise arch wire (MEAW)와 악간 고무줄을 이용한 치료는 효율적으로 하악 치아를 원심 경사할 수 있지만, 장치의 복잡성 때문에 제작이 어렵고 환자의 불편감이 증가하는 단점을 가지고 있다. 최근에 향상된 초탄성 Ni-Ti alloy wire는 교정력을 좀 더 효과적으로 전달할 수 있고, improved superelastic wire (ISW)를 이용한 tip-back은 디자인이 간단하기 때문에 간단한 조작으로 와이어를 제작할 수 있으며, 환자의 불편감이 감소할 수 있다. 본고에서는 향상된 초탄성 Ni-Ti alloy wire와 악간 고무줄을 이용하여 하악 구치부를 원심 경사이동한 증례를 소개하고, 효과적인 임상 적용을 위한 고려사항을 살펴보고자 한다.