수직력하에서 임프란트 나사형태에 따른 응력의 3차원 유한요소법적 분석

김우택,차용두,오세종,박상수,김현우,박양호,박준우,이건주,Kim, Woo-Taek,Cha, Yong-Doo,Oh, Se-Jong,Park, Sang-Soo,Kim, Hyun-Woo,Park, Yang-Ho,Park, Jun-Woo,Rhee, Gun-Joo 대한구강악안면외과학회 2001 대한구강악안면외과학회지 Vol.27 No.2

There are three designs of thread form in screw type implants: V-thread, Reverse buttress thread and Square thread. The purpose of this study was to find out how thread form designs have an influence on the equivalent stress, equivalent strain, maximum shear stress and maximum shear strain and which design of thread form generates more maximum equivalent stress and strain. 3-D finite element analysis was used to evaluate the stress and strain patterns of three tread types. The results of this study were as follow. 1. Under the 200N of axial load, the value of maximum equivalent stress is smallest in square thread and there is no significant difference between that of V thread and reverse buttress thread. 2. Under the 200N of axial load, the value of maximum equivalent strain is largest in V thread and smallest in square thread. 3. Under the 200N of axial load, the value of maximum shear stress is smallest in square thread and there is no significant difference between that of V thread and reverse buttress thread. 4. Under the 200N of axial load, the value of maximum equivalent strain is largest in V thread and there is no significant difference between that of square thread and reverse buttress thread. 5. Above results show that the square thread has special advantages in stress and strain compared with other thread types, especially in shear stess which is most determinant to implant-bone interface. Considering the superior biomechanical properties of square form implant, we presume that square form implant has better clinical results than the other types of implants in the same clinical conditions.

Transmandibular implant 를 이용한 하악 재건의 치험례

현정민,차용두,오세종,박준우,이건주 대한치과이식임플란트학회 1999 The Korean Academy of Implant Dentistry Vol.18 No.1

The resorption of the residual ridge of the edentulous patient has given some problems to be functionally restored to the patient and the dentists. As a result of the bone atrophy, the denture-bearing area becomes smaller and the function of the denture becomes lower. In the case of which the common denture cannot restore the function of the mandible, endosteal implants can be very helpful to replace it and has been performed. But even endosteal implants can not be used if there is no enough available bone to be placed. In that case, transmandibular implant has been generally acepted as an treatment option. This case report is to show the reconstruction of the completely edentulous mandible of a 70 year old male patient with the transmandibular implant. The surgery was done along the protocol of the BOSKER TMI SYSTEM, and the final denture was delivered at the 3rd month after the surgery. General problems such as infection, periodontal problem, implant loosening have not been detected by now.The patient was very satisfied with the results of the treatment and the subjective findings as the fucntional recovery, esthetics and the psychologic stability show good results. Thus the transmandibular implant seems to be the desirable treatment option to restore the function of the severly atrophic mandible.

편측 하악골 신장술에 의한 악관절의 변화에 관한 조직학적 연구

안정모(Jung Mo An),오세종(Se Jong Oh),차용두(Yong Doo Cha),권순용(Soon Yong Kwon),박영주(Young Ju Park),박준우(Jun Woo Park),이건주(Gun Joo Rhee) 대한구강악안면외과학회 2000 대한구강악안면외과학회지 Vol.26 No.6

The objective of this study was to find out whether the unilateral distraction of mandible has an influence on temporomandibular joint and if it does, how significant the influence is. Four beagle dogs were used in this study. Each dog had two implants placed into the left mandible. The mandible was distracted for 14days with an distraction device as an amount of 0.75mm, twice per day after osteotomy between two implants. Each animals were sacrificed at the second, fourth, sixth and eighth week after the total distraction amount of 10.5mm were gotten. Upon embedding and staining, the specimens were evaluated with a light microscope. The results were as follows. 1. For the second week group, the articular cartilage and osteoid seam of temporal bone and condyle were relatively well maintained. There were not any significant differences between distraction side and non distraction side. 2. For the fourth week group, the periosteal reaction was activated and the articular cartilage and osteoid seam of temporal bone and condyle were severely thickened - especially at posterior portion of distraction side. This findings revealed that the unilateral distraction forces has more influence on distraction side than on non distraction side, and on posterior portion than on anterior portion. 3. For the sixth and eighth week group, the thickness of meniscus in distraction side gradually recovered to the initial level. The thickened articular cartilage and osteoid seam of temporal bone and condyle were decreased in distraction side and showed relatively stable in non distraction side. From this results, we suggest that several considerations are required such as using an occlusal splint, maintaining the stability of bone distraction device and evaluating bone distraction rate to minimize the damages of temporomandibular joint tissues in early stage of distraction side.

방사선 조사후 매식한 임프란트와 관주에 따른 골치유에 대한 비교연구

홍성팔(Sung Pal Hong),이건주(Gun Joo Rhee),차용두(Yong Doo Cha),오세종(Se Jong Oh),현정민(Jung Min Hyun),최동주(Dong Joo Choi),박영주(Young Joo Park),박준우(Jun Woo Park) 대한구강악안면외과학회 2000 대한구강악안면외과학회지 Vol.26 No.1

In this study, the rate of bone formation and the pattern of bone to implant contact surface around HA coated implant and pure Ti implant inserted into the irradiated tibia of rabbit were compared. Sixteen mongrel mature male rabbits were used as experimental animal. Each rabbit received 15 Gy of irradiation. Four weeks after irradiation, two holes were prepared on the tibia of each rabbit for placement of HA coated type and pure Ti type implants. Prior to implant placement, one group received steroid irrigation and the control group was similarly irrigated with normal saline. This was immediately followed by placement of the two different types of implants. Postoperatively, tetracycline was injected intramuscularly for 3 days. For fluorescent labelling, 3 days of intramuscular alizarine red injection was given. 2 weeks before sacrifice, followed by intramuscular calcein green on the last 3 days before specimen collection. Each rabbit was sacrificed on the second, fourth, sixth and eighth week after the implantation. The specimens were observed by the light microscope and the fluorescent microscope. The results were as follows; 1. All implants inserted into the irradiated tibia of rabbit were free from clinical mobility and no signs of bony resorption were noted around the site of implant placement. 2. Under the light microscope, new bone formation proceeded faster around implants that received steroid irrigation compared to the control group irrigated with saline. Bone to implant contact surface was greater in the steroid irrigated group than the saline irrigated group. Therefore, better initial stabilization was observed in the group pretreated with steroid irrigation. 3. Under the light microscope. HA coated implants showed broader bone to implant contact surface than pure Ti implants, and HA coated implants had better bone healing pattern than pure Ti implants. 4. In the steroid pretreated group, acceleration of bone formation was demonstrated by fluorescent microscopy around the 2, 4 weeks group and the 6 weeks HA coated implant group. The difference in the rate of bone formation proved to be statistically significant(P<0.05). Faster bone formation was noted in the saline irrigated group in the 6 weeks pure Ti implants and 8 weeks group. The difference was not statistically significant(P<0.05). 5. For the rabbits that were sacrificed on the second and fourth week after the implant placements, the rates of bone formation around HA coated implants proceeded faster than those around pure Ti implants under the fluorescent microscopy. For the rabbits that were sacrificed on the sixth week after the implant placements, the rates of bone formation around pure Ti implants proceeded faster than those around HA coated implants under the fluorescent microscopy. But this result did not show statistical significance (P<0.05) For the rabbits that were sacrificed on the eighth week after the implant placements, the rates of bone formation around HA coated implants proceeded faster than those around pure Ti implants under the fluorescent microscopy. This result was statistically significant (P<0.05).