• 대한수의학회지
• /
• 제23권1호
• /
• pp.57-67
• /
• 1983

The present study was carried out to observe the histopathological changes in the mammary gland of lactating rats and rabbits injected with dexamethasone. White rats were intramuscularly injected with 0.25mg, 0.5mg or 1.0mg of dexamethasone sodium phosphate (containing $9{\alpha}$-fluoro-$16{\alpha}$-methylprednisolone, 5.0mg/ml) daily for 3 to 10 days on the 3rd day after parturition and white rabbits were intramammary infused with 4mg or 20mg of dexamethasone daily for 4 days on 7th day after parturition. The histopathological changes of the mammary glands, ovaries and adrenal glands of rats and rabbits were observed with light microscope. In the mammary glands of rats, the microscopic findings encountered were decrease of the milk in the alveolar lumina, necrosis and desquamation of epithelial cells, atrophy of alveoli, proliferation of fibroblasts and thickness of alveolar walls, destruction of alveoli, presence of fat droplets within the glandular epithelial cells, infiltration of mononuclear cells and proliferation of adipose tissue, which were relative to the dose and duration of injection. Especially, in the cases of the administration of large doses or long duration, there were severe fibrosis and focal necrosis of glandular tissue. In the mammary glands of rabbits, the morphological changes were similar to those findings in the rats. The milk in the alveolar lumina was decreased gradually according to the dose and duration of injection, while milk fat concentration regarded to increase. In the histological findings of ovaries, necrosis of granulosa cellos, vacuolization and necrosis of luteal cells, atrophy and necrotic foci in the corpora lutes were observed. In the adrenal glands, hyperemia, hemorrhage, vacuolization of adrenal cortical cells, necrotic foci and atrophy of adrenal cortex were observed.

• Imaging Science in Dentistry
• /
• 제51권1호
• /
• pp.73-80
• /
• 2021

Purpose: The purpose of this study was to evaluate the cone-beam computed tomographic (CBCT) imaging and histopathological characteristics of osteoradionecrosis(ORN) and medication-related osteonecrosis of the jaw(MRONJ). Materials and Methods: Ten surgical specimens from segmental mandibulectomy (3 ORN and 7 MRONJ) were analyzed using CBCT. The CBCT parameters were as follows: high-resolution mode (tube voltage, 90.0 kV; tube current, 4.00 mA; rotation time, 16.8 s; field of view, 56 mm×56 mm; thickness, 0.099 mm). Histopathological characteristics were evaluated using histological slides of the surgical specimens. The Pearson chi-square test was used to compare ORN and MRONJ in terms of CBCT findings(internal texture, sequestrum, periosteal reaction and cortical perforation) and histopathological characteristics(necrotic bone, inflammatory cells, reactive bone formation, bacteria, Actinomyces, and osteoclasts). A P value less than 0.05 was considered to indicate statistical significance. Results: MRONJ showed periosteal reaction on CBCT more frequently than ORN (7 of 7 [100%] vs. 0 of 3 [0%], P<0.05). Regarding histopathological characteristics, MRONJ showed osteoclasts more frequently than ORN (6 of 7 [85.7%] vs. 0 of 3 [0%], P<0.05). Conclusion: This study evaluated the CBCT imaging and histopathological characteristics of ORN and MRONJ, and the findings suggest that CBCT could be useful for the evaluation of ORN and MRONJ.

• 대한치과교정학회지
• /
• 제53권6호
• /
• pp.393-401
• /
• 2023

Objective: To investigate the long-term effects of 4-hexylresorcinol (4HR) on facial skeletal growth in growing male rats, with a focus on diabetic animal models. Methods: Forty male rats were used. Of them, type 1 diabetes mellitus was induced in 20 animals by administering 40 mg/kg streptozotocin (STZ), and they were assigned to either the STZ or 4HR-injected group (STZ/4HR group). The remaining 20 healthy rats were divided into control and 4HR groups. We administered 4HR subcutaneously at a weekly dose of 10 mg/kg until the rats were euthanized. At 16 weeks of age, whole blood was collected, and microcomputed tomography of the skull and femur was performed. Results: All craniofacial linear measurements were smaller in the STZ group than in the control group. The mandibular molar width was significantly smaller in the 4HR group than in the control group (P = 0.031) but larger in the STZ/4HR group than in the STZ group (P = 0.011). Among the diabetic animals, the STZ/4HR group exhibited significantly greater cortical bone thickness, bone mineral density, and bone volume than the STZ group. Serum testosterone levels were also significantly higher in the STZ/4HR group than in the STZ group. Conclusions: 4HR administration may have divergent effects on mandibular growth and bone mass in healthy and diabetic rats. In the context of diabetes, 4HR appears to have beneficial effects, potentially through the modulation of mitochondrial respiration.

• 대한치과보철학회지
• /
• 제49권2호
• /
• pp.128-137
• /
• 2011

연구 목적: 자기공명주파수 분석, 페리오테스트, 풀림 토크는 임플란트의 안정성을 측정하기 위한 방법으로 알려져 있다. 이 방법들은 골 상태와 임플란트 형태에 영향을 받는다. 본 연구에서는 골유착이 재현된 아크릴 레진 실험 모델에서 임플란트가 결합된 골의 양을 변화하고 경부의 골 상실양이 증가하였을 경우, 자기공명주파수 분석, 페리오테스트, 풀림 토크 측정에 어떠한 영향을 주는지 알아보고 이들 상호간의 관계를 알아보고자 하였다. 연구 재료 및 방법: 골 유착을 재현하기 위하여 임플란트를 알루미늄 틀에 나사로 고정한 후 자가중합형 아크릴릭 레진의 가루와 용액을 틀 안에 부어서 중합을 시켰다. 임플란트와 결합된 레진의 두께를 조정하여 골 결합 두께를 각각 1, 3, 5, 10 mm인 경우로 재현하였다. 그 후 임플란트 주변 경부 골 상실 양이 1, 3, 5 mm인 경우를 재현하였다. 각각의 재현된 골 조건에서는 4 mm 직경의 직선형 임플란트, 같은 직경의 tapered 형 임플란트, 5 mm 직경의 tapered 형의 3가지 임플란트가 각각 5개씩 사용되었다. 모든 골 조건에서 자기공명주파수 분석과 페리오테스트 측정이 이루어졌으며 골 결합 두께 1, 3 mm 시편에서는 풀림 토크가 측정되었다. 결과: 골 결합 두께가 증가하거나 임플란트 직경이 증가할수록 통계적으로 유의하게 ISQ 값은 증가하였고, 페리오테스트 값은 감소하였다 (P<.001, P<.001). 임플란트 경부에 주위 골 상실 양이 커질수록 ISQ 값은 감소하였고, 페리오테스트 값은 증가하였다 (P<.001). ISQ 값과 페리오테스트 t값은 매우 강한 상관관계를 나타냈다 (r = -0.99, P<.001). ISQ값과 풀림토크는 약한 상관관계를 나타냈으며 (r = 0.52, P<.001), 페리오테스트 값과 풀림 토크도 약한 상관관계를 나타냈다 (r = -0.52, P<.001). 결론: 레진으로 재현한 골의 양이 증가할수록, 임플란트의 직경이 증가할수록, 경부의 골 상실양이 적을수록 임플란트 안정성이 증가함을 확인할 수 있었다. 또한 본 연구에서는 ISQ 값과 페리오테스트 값의 강한 상관관계를 밝힐 수 있었다.

• 대한치과보철학회지
• /
• 제49권2호
• /
• pp.168-176
• /
• 2011

연구 목적: 임플란트 식립시에 발생할 수 있는 열변화는 임플란트의 실패를 초래할 수 있다. 식립토크에 따른 열변화 양상을 파악함으로 임플란트의 형태에 따른 차이점과 적절한 식립토크가 어떤 것인지 파악하고자 한다. 연구 재료 및 방법: 실험재료로는 두께 15 - 20 mm의 소 견갑골을 가로 35 mm, 세로 40 - 50 mm 크기가 되도록 골편으로 자르고 이중에 피질골의 두께가 2 - 3 mm 되는 표본을 선정한 후 표본의 반을 $36.5^{\circ}C$ 수조에 실온 $25^{\circ}C$에 노출 시켜 내부 온도는 평균 $36.5^{\circ}C$, 표면온도 $28^{\circ}C$가 되도록 설계하였다. $4.5{\times}10\;mm$의 외부육각을 가지는 Br${\aa}$nemark 형태의 임플란트와 $4.8{\times}10\;mm$의 Microthread 형태를 지니는 내부연결 형태의 임플란트를 과도한 식립토크로 식립하고 온도 측정은 계측점에서 0.2 mm 이내에 열전대를 위치시켜 기록하였다. 삼차원유한요소 분석은 골의 형태를 가로 4 cm, 세로 4 cm, 높이 2 cm의 직육면체로 가정하고, 직육면체 윗면에서 2 mm까지를 피질골, 그 아랫부분을 해면골이라고 가정하였다. 마찰열은 매식이 종료된 상황에서 골에 남는 cavity 모양을 기초로 경계조건을 부여하였다. CAD 프로그램인 SolidWorks 소프트웨어를 이용하였고, 이를 유한요소 구조해석용 프로그램인 Abaqus 6.9-1로 불러들여 해석하였다. 결과 및 결론: In vitro실험에서 Microthread type의 임플란트가 상대적으로 더 높은 최고점 온도를 보여주고 있으며 이는 임플란트의 형태에 따른 마찰열 발생이 주요 원인으로 보인다. 유한요소분석을 통해 살펴본 결과 Br${\aa}$nemark 형태의 임플란트의 경우 50 Ncm이상에서 Microthread를 가지는 형태의 경우에는 35 Ncm이상에서 Eriksson 등이 보고한 역치를 초과하는 온도가 발생하였다. 이를 통해 볼 때 Microthread type 이 식립토크에 따른 온도 증가가 더 민감함을 알 수 있다. 실험결과를 통해서 서로 다른 형태의 임플란트 식립시에 임플란트의 형태에 따라 적절한 삽입토크를 부여하는 것이 성공적인 임플란트 시술에 중요한 요소 중에 하나임을 알 수 있었다. 특히 Microthread를 갖는 임플란트 형태는 높은 초기고정성을 얻을 수 있다는 장점이 있는 반면 과도한 식립 토크로 인한 열 손상 가능성을 가질 수 있으므로 골량과 골질의 신중한 평가와 적절한 수술기법이 필요할 것으로 생각된다.

• 구강회복응용과학지
• /
• 제30권3호
• /
• pp.215-222
• /
• 2014

본 연구는 수평적, 수직적 안면 골격 유형에 따른 하악 전치부 치조골의 형태학적 차이를 알아보기 위하여 시행 하였다. 연구 재료 및 방법: 40명의 Cone-beam computed tomography (Cone-beam CT)를 선별하여, 4개 군으로 분류하였다. Cone-beam CT 자료를 이용하여 하악 전치부 치조골의 부피($mm^3$), 하악 4절치 치축 기준 시상단면의 단면적(총 단면적, 해면골 단면적: $mm^2$), 백악법랑경계(cemento-enamel junction: CEJ) 2 mm, 3 mm 아래 순, 설측 치조골 두께를 측정하였다. 통계분석은 GLM, Kruskal-Wallis test and Tukey HSD를 사용하였다. 결과: 측절치의 백악법랑경계 2 mm, 3 mm 하방 설측 치조골 두께가, Class I low angle군이 나머지 3군 보다 두꺼웠다 (P < 0.05). 하악 전치 치조골의 부피, 전체 치조골 및 해면골의 단면에서의 통계적으로 유의한 차이는 없었다. 결론: Class I low angle군은 Class II high angle군에 비해 하악 전치 치조골의 설측 부위가 더 두껍다.

• Journal of Periodontal and Implant Science
• /
• 제37권4호
• /
• pp.791-803
• /
• 2007

The purpose of this study was to evaluate exophytically vertical bone formation in residual ridge of the beagle dog by the concept of guided bone regeneration with a titanium reinforced e-PTFE membrane combined with irradiated cancellous human bone. Twelve male beagle dogs(mean age 1.5 years and mean weight 12kg) were used for this study. The alveolar ridges after extraction of all mandibular premolars were surgically and horizontally removed. At 8 weeks after extractions, full-thickness flap was reflected and cortical bone was removed with round bur and copious irrigation. Rectangular parallelepiped(10mm in length, 5mm in width, and 4mm in height) bended with titanium-reinforced e-PTFE(TR e-PTFE) membrane was placed on the decorticated alveolar ridge, fixed with metal pins and covered with full-thickness flap and assigned as a control group. Test groups ere treated with TR e-PTFE membrane filled with irradiated cancellous human bone. Of twelve beagle dogs, four control dogs and four test dogs without membrane exposure to oral cavity were sacrificed at 8 and 16 weeks respectively. The surgical sites were dissected out, fixed in 4% buffered formaldehyde, dyed using a Villanueva staining technique, and processed for embedding in plastic resin. The cutting and grinding methods were routinely processed for histologic and histomophometric analyis of exophytic bone formation as well as statistical analysis. The results of this study were as follows: 1. Exophytic bone formation in the both of experimental groups was increased respectively after surgery from 23.40% at 8 weeks to 46.26% at 16 weeks in the control groups, from 40.23% at 8 weeks to 47.11% at 16 weeks in the test groups(p<0.05). 2. At 8 weeks after surgery, exophytic bone formation was made 40.23% in the test groups and 33.40% in the control groups. Exophytic bone formation was significantly made in the test group more than in the control group. At 16 weeks after surgery, exophytic bone formation was made 44.11% in the test groups and 46.26% in the control groups. Exophytic bone formation was made in the test groups more than in the control groups, but there was no statistically significant differences. 3. The membrane was fixed with metal pins to closely contact it to the bone surface. So, collapse and deviation of the membrane could be prevented and in growth of connective tissue also could be blocked from the periphery of the membrane. On the basis of these findings, wee suggest that intraoral experimental model for exophytic bone formation may be effective to evaluate the effect of bone graft material. And it indicates that combined use of membrane and ICB graft material is more effective than use of membrane only for exophytic bone formation.

• 대한한방부인과학회지
• /
• 제18권1호
• /
• pp.128-141
• /
• 2005

Objective : This study was undertaken to investigate the effects of Eucommiae Cortex on the osteoporosis in ovariectomized rats. Materials and Methods : We used Sprague-Dawley female rats in 8-week-old. They were divided into three groups. Sample group was ovariectomized and administered with 10 mg/100 g/day Eucommiae Cortex extract solution for 10 weeks. Control group was ovariectomized and sham group was conducted by sham's operation. And control group and sham group were administered with normal saline as the same way. We measured rats's body and uterus weight and also measured the serum levels of Ca, phosphorus and ALP. We stained the specimens of rat's tibial bones with Goldner's modified Masson's Trichrome and then examined bone histomorphometry with Bioquant computer program of image analysis system. We measured the thickness of osteoid and callus as static parameters and measured bone volume and mineral apposition rate as dynamic parameters. We observed the expressions of RANKL and OPG mRNA of the tibial bone by RT-PCR. Results : The body weight was significantly (p<0.05) increased in control and sample groups compared with sham group, respectively. The uterus weight was significantly (p<0.05) decreased in control and sample group compared with sham group. In the change of Ca, phosphorus and ALP there were no significant changes among three groups. There were no significant changes of trabecula cortical and osteoid bones' thickness and volume. But trabecula mineral apposition rate (MAR) was significantly (p<0.05) increased in sham and sample group compared with control group. In the expression of RANKL mRNA, sample group was decreased compared with control group, and in that of OPG mRNA, sample group was increased compared with control group. Conclusion : This study shows that Eucommiae Cortex has the beneficial effects on bone histomorphometry and metabolism in the ovariectomized rats. We suggest that Eucommiae Cortex be useful for the treatment of osteoporosis.

• 치과방사선
• /
• 제23권2호
• /
• pp.229-250
• /
• 1993

This study was performed to investigate the morphological and structural changes of bone tissues and the effects of irradiation on the mandibular bodies of rats which were fed low calcium diets. In order to carry out this experiment, 160 seven-week old Sprague-Dawley strain rats weighing about 150 gm were selected and equally divided into one normal diet group of 80 rats and one low calcium diet group with the remainder. These groups were then subdivided into two groups, 40 were assigned rats for each subdivided group, exposed to radiation. The Group 1 was composed of forty non-irradiated rats with normal diet, Group 2 of forty irradiated rats with normal diet, Group 3 forty non-irradiated rats with low calcium diet, and Group 4 forty irradiated rats with low calcium diet. The two irradiation groups received a single dose of 20 Gy on the jaw area only and irradiated with a cobalt-50 teletherapy unit. The rats with normal and low calcium diet groups were serially terminated by ten on the 3rd, the 7th, the 14th, and the 21st day after irradiation. After termination, both sides of the dead rats mandible were removed and fixed with 10% neutral formalin. The bone density of mandibular body was measured by use of bone mineral densitometer(Model DPX -alpha, Lunar Corp., U.SA). Triga Mark ill nuclear reactor in Korea Atomic Research Institute was used for neutron activation and then calcium contents of mandibular body were measured by using a 4096 multichannel analyzer (EG and G ORTEC 919 MCA, U.SA). Also the mandibular body was radiographed with a soft X-ray apparatus(Hitex Co., Ltd., Japan). Thereafter, the obtained microradiograms were observed by a light microscope and were used for the morphometric analysis using a image analyzer(Leco 2001 System, Leco Co., Canada). The morphometric analysis was performed for parameters such as the total area, the bone area, the inner and outer perimeters of the bone. The obtained results were as follows: 1. In the morphometric analysis, total area and outer perimeter of the mandibular bodies of Group 3 were a little smaller than that of Group 1. The mean bone width and bone area were much smaller than that of Group 1 and the inner perimeter of Group 3 was much longer than that of Group 1. The total area and outer perimeter of Group 2 and Group 4 showed little difference. The mean bone width and bone area of Group 4 were smaller than that of Group 2 and the inner perimeter of Group 4 was longer than that of Group 2. 2. The remarkable decreases of the number and thickness of trabeculae and also the resorption of endosteal surface of cortical bone could be seen in the microradiogram of Group 3, Group 4 since the 3rd day of experiment. On the 21st day of experiment, the above findings could be more clearly seen in Group 4 than in Group 3. 3. The bone mineral density of Group 3 was lesser than that of Group 1 and the bone mineral density of Group 4 was lesser than that of Group 2 on the 7th, 14th, 21st days. The irradiation caused the bone mineral density to be decreased regardless of diet. In the case of Groups with low calcium diet, the bone mineral density was much decreased on the 21st day than on the 3rd day of experiment. 4. The calcium content in mandible of Group 3 was smaller than that of Group 1 throughout the experiment. roup 4 showed the least amount of calcium content. The irradiation caused the calcium content to be decreased regardless of diet. In the case of Groups with low calcium diet, the calcium content was much decreased on the 21st day than on the 3rd day of experiment. In conclusion, the present study demonstrated that morphological changs and decrease of bone mass due to resorption of bone by low calcium diet, and that the resorption of bone could be found in the spongeous bone and endosteal surface of cortical bone. So the problem of resorption of bone must be considered when the old and the postmenopausal women are taken radiotherapy because the irradiation seems to be accelerated the resorption of osteoporotic bone.

• Journal of Periodontal and Implant Science
• /
• 제43권1호
• /
• pp.30-36
• /
• 2013

Purpose: Implant stability at the time of surgery is crucial for the long-term success of dental implants. Primary stability is considered of paramount importance to achieve osseointegration. The purpose of the present study was to investigate the correlation between the insertion torque and primary stability of dental implants using artificial bone blocks with different bone densities and compositions to mimic different circumstances that are encountered in routine daily clinical settings. Methods: In order to validate the objectives, various sized holes were made in bone blocks with different bone densities (#10, #20, #30, #40, and #50) using a surgical drill and insertion torque together with implant stability quotient (ISQ) values that were measured using the Osstell Mentor. The experimental groups under evaluation were subdivided into 5 subgroups according to the circumstances. Results: In group 1, the mean insertion torque and ISQ values increased as the density of the bone blocks increased. For group 2, the mean insertion torque values decreased as the final drill size expanded, but this was not the case for the ISQ values. The mean insertion torque values in group 3 increased with the thickness of the cortical bone, and the same was true for the ISQ values. For group 4, the mean insertion torque values increased as the cancellous bone density increased, but the correlation with the ISQ values was weak. Finally, in group 5, the mean insertion torque decreased as the final drill size increased, but the correlation with the ISQ value was weak. Conclusions: Within the limitations of the study, it was concluded that primary stability does not simply depend on the insertion torque, but also on the bone quality.