• Journal of Dental Rehabilitation and Applied Science
• /
• v.24 no.2
• /
• pp.203-211
• /
• 2008

Minimizing damage to anatomical structure is a prerequisite for skeletal anchorage system to install a miniscrew. This research has focused on evaluating the stability and safety of installation in the maxillary molar buccal area, in which most miniscrews are installed clinically and initial fixation is weak. CT (computerized tomography)images were taken for surveying the possibility of damaging to adjucent teeth in accordance with installation angle. If we install a mini-screw($1.2{\times}6.0mm$) in the maxillary molar buccal area, it would be located generally in the 5~8mm upper of CEJ and 3~5mm inner of the cortical bone surface. We has measured the space between roots And comparison has been made for gender and the space between roots in accordance with the 3 different angles of installation(30 degree, 40 degree, 60 degree) in 3 categories. Category 1 : between 1st molar and 2nd molar Category 2 : between 1st molar and 2nd premolar Category 3 : between 1st premolar and 2nd premolar The result are as follow; 1. The space for category 1 was significantly small. 2. For the installation angle, it was safer to install with steeper angle in category 1 and category 2, but not in category 3. According to these results, the installation a miniscrew in category 2, 3 is safer than in category 1. And it is safer to install with steeper angle in category 1 and category 2.

• Journal of the Korean Academy of Esthetic Dentistry
• /
• v.18 no.1
• /
• pp.27-32
• /
• 2009

오늘날 단일치 임플란트의 식립은 현재 시행되고 있는 가장 일반적인 임플란트 술식 중 하나이며, 상악 전치부는 이중 가장 흔하게 시행되는 식립 부위 중하나이다. 그럼에도 불구하고 상악 전치부 단일 상실치에 대한 치료 계획은 구강 내 다른 어떤 부위보다 복잡하며 고도로 심미성을 요구하는 부위로서 아무리 경험이 많고 기술이 뛰어난 치과의사라 할지라도 시술할 때마다 큰 도전으로 여겨지는 경우가 대부분일 것이다. 상악 전치부에서 임플란트 보철의 심미적 성공을 이루기 위해서는 모든 구성 요소 하나하나에서 심미적 결과를 이룩하여야 하고 이 결과들이 완벽하게 조화를 이루게 하여야 하며 이는 결코 쉬운 일이 아닐 것이다. 시술 시 교과서의 그림처럼, 모형에 식립해 본 것처럼 쉽게 되지 않는 것은 물론 구강 내 환경이 모형과 다를 리 만무한 것이 당연한 첫 번째 이유이며 뿐만 아니라 환자 대부분의 경우 모형처럼 완벽한 경 연조직이 갖추어진 상태에서 치아만 상실된 경우는 거의 찾아볼 수 없기 때문인 이유도 크다. 즉, 원하는 위치에 식립을 하고 장기간의 심미적 유지를 위해서는 경 연조직에 대한 처치가 필수적인 경우가 대부분이라는 이야기이다. 이를 간과하고 식립한 경우 추후 심각한 bone의 resorption, 그에 따르는 gingiva의 끔찍한 recession, 용납할 수 없는 비심미적 보철물의 제작은 불을 보듯 뻔한 결과가 될 것이다. 따라서 상악 전치부 식립 치료계획 시 치과의사는 성공적 결과에 영향을 미칠 수 있는 모든 요소에 촉각을 곤두세우고 이들의 완벽한 처치에 최선을 다 해야할 것이다.

• The Journal of Korean Academy of Prosthodontics
• /
• v.55 no.1
• /
• pp.1-8
• /
• 2017

Purpose: The purpose of this study is to compare the accuracy of the CT guided implant template that was produced by using an intraoral scanner according to the edentulous distance. Materials and methods: Five maxillary casts were fabricated using radiopaque acrylic resin with the second premolars, first molars, and second molars missing. Then a virtual cast was acquired by scanning each resin cast. Implant treatment was planned on the missing sites by superimposing the presurgical CT DICOM file and the virtual cast. Then the implants were placed using a surgical template followed by postsurgical CT scan. The distance and angle of the platform and apex between the presurgical implant and postsurgical implant were measured using the X, Y, and Z axis of the superimposed presurgical CT and postsurgical CT via software followed by statistical analysis using Kruskall-Wallis test and Mann-Whitney test. Results: The implant placement angle error increased towards the second molars but there was no statistically significant difference. The implant placement distance error at the platform and apex also increased towards the second molars and there was a statistically significant error at the second molars. Conclusion: Although the placement angle had no statistically significant difference between the presurgical implant and postsurgical implant, the placement distance at the platform and apex showed a larger error and a statistically significant difference at the second molar implant.

• Journal of the Korean Academy of Esthetic Dentistry
• /
• v.21 no.1
• /
• pp.23-42
• /
• 2012

심미 영역에서 발치후 즉시 식립시 가장 기본이 되는 성공의 핵심 요소는, 발치후 발치와 리모델링에 대한 생물학적 이해와 3차원적으로 정확한 임플란트의 식립 위치다. 그에 더해서, 상악 측절치 부위는 중절치나 견치 부위와 다른 해부학적 특성을 갖고 있고 이는 발치후 즉시 식립을 할 때 치료법을 결정하고 좋은 결과를 얻는데 있어 매우 중요한 고려 요소가 된다. 순측 치조골의 함몰 정도, 인접 상악 전치 치근의 수렴 정도, 크라운-치근이 이루는 각도와 치조골 프로파일 이 세가지를 치료 전에 잘 평가하고 치료 전략을 세운다면 심미적으로 우수한 좋은 결과를 얻는데 도움이 될 것이다.

• The Journal of Korean Academy of Prosthodontics
• /
• v.46 no.2
• /
• pp.193-200
• /
• 2008

Statement of problem: There have been a few studies about unsplinted implant retainted maxillary overdenture. Purpose: The purpose of this study was to examine the effect of different position of implant for 2 implants-retained maxillary overdenture. Materials and methods: Three-dimensional finite element models were used to reproduce an edentulous human maxilla with an implant-retained overdenture. Two implants in the canine tooth positions on both side and in the second premolar tooth positions on both side models were examined. Axial loads of 100 N were applied to the occlusal surface at the right first molar tooth positions. Maximum stress at the implant-bone interface and stress at the cortical bone surface just under the loading point were observed. Results and conclusion: Within the limits of this study, maximum stresses were concentrated around implant of canine position at loading side. The second premolar area was thought to be more favorable to distribution of stress on mucosa, alveolar bone and implants than canine area for maxillary overdenture.

• The korean journal of orthodontics
• /
• v.35 no.1 s.108
• /
• pp.35-42
• /
• 2005

There is lack of data for the amount of vertical bone in the midpalatal region for miniscrew implantation. The purpose of this study was to measure the structure of the midpalatal suture area using CT image and V-works 4.0 program (Cybermed Inc, Seoul, Korea). CT images of 14 male and 14 female adults were reconstructed. In detail, it was 1) to measure the length of maxilla on the midsagittal plane 2) to measure vertical bone height in the midpalatal area 3) to establish the zone of safety for miniscrew implantation. The following results were obtained. The mean length of ANS-PNS was 51.08mm in males and 47.34mm in females. There was a statistically significant difference between males and females (p<0.05). The vertical bone height of the midpalatal suture area was above 0mm except for 6mm posterior from the central Point of ANS-PNS in males The zone of safety was located 19.43mm posterior from the ANS in males while it was 17.62mm in females along the palatal plane. These results support that the safety zone of the midpalatal area is suitable for screw implantation. Midpalatal miniscrew implantation is a powerful tool in modern orthodontics Through many applications. it can expand the modern orthodontic field.

• Journal of the Korean Academy of Esthetic Dentistry
• /
• v.27 no.2
• /
• pp.97-104
• /
• 2018

Mandibular anterior region has high implant survival rates and better accessibility compared with any other region. Even if there are possibilities for perforation on lingual cortical bone due to improper drilling and bleeding caused by lingual artery damage, mandibular anterior region is a safe region because less amount of major anatomical structures exist compared with other regions. However, because of narrow bucco-lingual width of alveolar ridge, it is challengeable to obtain esthetic implant prosthesis. Although patients are less sensitive subjectively, mandibular anterior region is as difficult as maxillary anterior region in that implant placement location plays a critical role on the prognosis of implant prosthesis. One-piece implant is a very useful option for mandibular anterior region. Considering the narrow roots and thin alveolar bone of mandible, it is clinically difficult for implant diameter to be greater than 3mm In this case, we could approach the esthetic restoration in mandibular anterior region with one-piece implant and immediate loading.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.25 no.1
• /
• pp.61-71
• /
• 2009

Anchorage control is important in orthodontic treatment. Recently miniscrew is widly used as maximum anchorage in orthodontic treatment, and then it is important to install miniscrew safely without damaging adjacent anatomic structure. In a view of Miniscrew's stability, maxilla is unfavorable than mandible, and moreover maxillary soft buccal bone has disadvantage on stability. so palatal area comes into notice for installation area. We measured distance between palatal roots and bone thickness at midpalatal area using 3D computed tomography, and have found following results. 1. On the comparison of distance between palatal roots, the distance between 2nd premolar and 1st molar was significantly longest and the distance between premolars was significantly shortest. 2. Going toward lateral area from midpalatal suture and posterior area from zero point, bone thickness significantly became shorter and shorter. And 5.0mm palatal sagittal plane has more significance decrease of bone thickness than 2.5mm palatal sagittal plane. According to these results, we can conclude that the palatal installation of miniscrew between 2nd premolar and 1st molar is safest. And it is more safe that comes closer to midpalatal suture and to anterior area in regard to incisive canal.

• The korean journal of orthodontics
• /
• v.40 no.3
• /
• pp.167-175
• /
• 2010

Objective: The aim of this study was to validate the Periotest values for the prediction of orthodontic mini-implants' stability. Methods: Sixty orthodontic mini-implants (7.0 mm $\times$ $\emptyset1.45$ mm; ACR, Biomaterials Korea, Seoul, Korea) were inserted into the buccal alveolar bone of 5 twelve month-old beagle dogs. Insertion torque (IT) and Periotest values (PTV) were measured at the installation procedure, and removal torque (RT) and PTV were recorded after 12 weeks of orthodontic loading. To correlate PTV with variables, the cortical bone thickness (mm) and bone mineral density (BMD) within the cortical bone and total bone area were calculated with the help of CT scanning. Results: The BMD and cortical bone thickness in mandibular alveolus were significantly higher than those of the maxilla (p < 0.05). The PTV values ranged from -3.2 to 4.8 for 12 weeks of loading showing clinically stable mini-implants. PTV at insertion was significantly correlated with IT (-0.51), bone density (-0.48), cortical bone thickness (-0.42) (p < 0.05) in the mandible, but showed no correlation in the maxilla. PTV before removal was significantly correlated with RT (-0.66) (p < 0.01) in the mandible. Conclusions: These results show that the periotest is a useful method for the evaluation of mini-implant stability, but it can only be applied to limited areas with thick cortical and high density bone such as the mandible.

• The Journal of Korean Academy of Prosthodontics
• /
• v.51 no.4
• /
• pp.252-260
• /
• 2013

Purpose: After the introduction of concept of osteointegration, dental implantology have been successful procedure in the dental field. Recently, it has shown successful results when used to restore single tooth missing. Considering the difference in bone quality of the mandible and maxilla, and the increased occlusal force in the posterior region, the success rates in each region may be different. In this study, success rates of single implants placed in the mandibular first and second molar areas were analyzed. Materials and methods: The subjects were patients (284 patients, 308 implants) who had been operated with single implant installation from 2002 to 2009 in seven dental clinics in Daegu city. One hundred sixty eight implants were placed in the mandibular 1st molar and 140 implants were placed in the mandibular 2nd molar. They were analyzed according to implant site, age, sex, length and diameter. Results: The survival rates of single implant of this study were 97.6% in the mandibular 1st molar and 92.9% in the mandibular 2nd molar. In the mandibular 1st molar, 4 implants were failed. In the mandibular, 2nd molar, 10 implants were failed. Conclusion: The restoration of the mandibular 1st molar using single implant was found to be clinically acceptable treatment and showed higher survival rate than mandibular 2nd molar single implant. Single implant in mandibular 2nd molar needs careful consideration of poor bone quality, risk of overloading and anatomical structure of the mandible.