• Journal of Periodontal and Implant Science
• /
• 제47권1호
• /
• pp.51-63
• /
• 2017

Purpose: Following tooth extraction, alveolar ridge preservation (ARP) can maintain the dimensions of ridge height and width. Although previous studies have demonstrated the effects of ARP, few if any studies have investigated the compressive force applied during grafting. The aim of this study was to determine the effects of different compressive forces on the graft materials during ARP. Methods: After tooth extraction, sockets were filled with deproteinized bovine bone mineral with 10% porcine collagen and covered by a resorbable collagen membrane in a double-layered fashion. The graft materials were compressed using a force of 5 N in the test group (n=12) and a force of 30 N in the control group (n=12). A hidden X suture was performed to secure the graft without primary closure. Cone-beam computed tomography (CBCT) was performed immediately after grafting and 4 months later, just before implant surgery. Tissue samples were retrieved using a trephine bur from the grafted sites during implant surgery for histologic and histomorphometric evaluations. Periotest values (PTVs) were measured to assess the initial stability of the dental implants. Results: Four patients dropped out from the control group and 20 patients finished the study. Both groups healed without any complications. The CBCT measurements showed that the ridge volume was comparably preserved vertically and horizontally in both groups (P>0.05). Histomorphometric analysis demonstrated that the ratio of new bone formation was significantly greater in the test group (P<0.05). The PTVs showed no significant differences between the 2 groups (P>0.05). Conclusions: The application of a greater compressive force on biomaterials during ARP significantly enhanced new bone formation while preserving the horizontal and vertical dimensions of the alveolar ridge. Further studies are required to identity the optimal compressive force for ARP.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제36권3호
• /
• pp.103-110
• /
• 2014

Purpose: The current gold standard for clinical jawbone formation involves autogenous bone as a graft material. In addition, demineralized dentin can be an effective graft material. Although demineralized dentin readily induces heterotopic bone formation, conventional decalcification takes three to five days, so, immediate bone grafting after extraction is impossible. This study evaluated the effect of vacuum ultrasonic power on the demineralization and processing of autogenous tooth material and documented the clinical results of rapidly processed autogenous demineralized dentin (ADD) in an alveolar defects patient. Methods: The method involves the demineralization of extracted teeth with detached soft tissues and pulp in 0.6 N HCl for 90 minutes using a heat controlled vacuum-ultrasonic accelerator. The characteristics of processed teeth were evaluated by scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Bone grafting using ADD was performed for narrow ridges augmentation in the mandibular area. Results: The new processing method was completed within two hours regardless of form (powder or block). EDS and SEM uniformly demineralized autotooth biomaterial. After six months, bone remodeling was observed in augmented sites and histological examination showed that ADD particles were well united with new bone. No unusual complications were encountered. Conclusion: This study demonstrates the possibility of preparing autogenous tooth graft materials within two hours, allowing immediate one-day grafting after extraction.

• 치과방사선
• /
• 제28권1호
• /
• pp.87-109
• /
• 1998

The present study was designed to elucidate the effects of the Co-60 γ irradiation and/or calcium­deficient diet on the dentin and cementum formation of rat molar. The pregnant three-week old Sprague­Dawley rats were used for the study. The experimental group was divided into two groups, irradiation/normal diet group and irradiation/calcium-deficient diet group. The control group was non­irradiation/normal diet group. The abdomen of the rats at the 19th day of pregnancy were irradiated with single absorbed dose of 350cGy. The rat pups were sacrificed on the 14th day after delivery and the maxillae including molar tooth germ were taken. The specimens including the 1st molar tooth germ were prepared to make tissue sections for light and transmission electron microscopy. Some of tissue sections for light microscopy were stained immunohistochemically with anti-fibronectin antibody. The results were as follows; 1. The Hertwig's epithelial root sheath cells, which are related to the differentiation of the tooth-forming cells, showed irregular cellular arrangement, decrease of intercellular junctional complex, and decreased immunoreactivity to the fibronectin after irradiation. These were more severe in the irradiation/calcium-deficient diet group. 2. The cementoblasts at the cementum-forming area showed chromatin clumpings after irradiation. The immu noreactivity to the fibronectin was weaken after irradiation, especially irradiation/calcium-deficient diet group. 3. The odontoblasts at the dentin-forming area showed increase of lysosomes in the cytoplasm and destruction of intercellular junctional complex. The irradiation/calcium-deficient diet group showed decrease of number and density of the electron dense particles and a large number of vacuoles scattered in the dentin matrix. The immunoreactivity was weaken.

• 한국발생생물학회지:발생과생식
• /
• 제13권2호
• /
• pp.89-95
• /
• 2009

p63은 다양한 상피 조직의 줄기세포와 전구세포에 존재한다는 사실이 잘 알려져 있으나, 치아 형성, 특히 사기질과 뿌리 형성시기에서의 p63 위치느 ㄴ아직 연구해야 할 과제로 남아 있다. 본 연구에서는 p63이 치아 발생 동안 치아상피에 편재하여 나타나는 것을 면역조직화학 기법을 이용하여 확인하였다. p63은 피부, 모낭, 구강점막 그리고 턱밑샘 도관을 포함하는 상피의 바닥층과 바닥위층에 위치하였다. 그러나 치아 부위에서는 치아관의 모든 세포, 사기질기관, 헤르트비히 뿌리상피집 그리고 말라세쯔 상피잔사에 p63이 관찰되었다. 이 결과는 치아 발생 중 p63이 줄기세포 유지 외에도 다른 기능을 한다는 사실을 보여준다.

• 대한소아치과학회지
• /
• 제39권1호
• /
• pp.66-72
• /
• 2012

자가치아이식이란 자신의 치아를 구강 내의 한 위치에서 다른 발치와나 외과적으로 형성된 치조와로 이동시키는 술식이다. 통상적으로 이 술식은 상실되거나 보존하기 힘든 제1대구치를 다른 치아로 대체하거나, 매복된 견치를 악궁의 정상 위치로 이동시키거나, 전치부와 같이 심미적으로 중요한 부위의 상실된 치아를 소구치로 대체하는 경우에 많이 사용된다. 자가치아이식을 성공적으로 수행하기 위해서는 세심한 수술 기법과 더불어 적절한 증례 선택이 중요한데, 이식할 치아는 치근 발육이 1/2~3/4 정도 이루어진 미성숙 치아가 유리하고 근단공이 넓을수록 치수 재혈관화의 가능성도 높아져 이후의 근관 치료의 필요성도 줄일 수 있다. 본 증례들은 소아에서 치근단 미완성 치아의 자가치아이식을 통해 임상적, 방사선학적으로 양호한 치유 결과를 얻었고, 별도의 근관 치료 없이 양호한 치수 치유 결과를 보였기에 보고하는 바이다.

• Imaging Science in Dentistry
• /
• 제32권1호
• /
• pp.1-10
• /
• 2002

Purpose: To observe the histopathological changes following irradiation on the wound healing after tooth extraction in the rachitic rats. Materials and Methods: In order to carry out this study, the rats were divided into four groups: Group 1 (normal diet/non-irradiation group), Group 2 (normal diet/irradiation group), Group 3 (rachitogenic diet/non-irradiation group), and Group 4 (rachitogenic diet/irradiation group). Rachitic changes were induced with rachitogenic diet No. 2 (high calcium, low phosphorus, and Vitamin D deficient diet) for 5 weeks. After the extraction of both maxillary first molars of the rats in Group 2 and 4, the head and neck of the rats were irradiated with single absorbed dose of 10 Gy. The rats were sacrificed at the 1st, 5th, 10th, and 15th day after tooth extraction. The specimens including the extraction wound were sectioned, stained with the hematoxylin-eosin and Masson's trichrome method and examined under the light microscope. Results: In the Group 2, the amount of newly formed bone trabeculae on the periphery of extraction socket and osteoblastic activity were reduced. In the Group 3, epithelial fusion was not revealed on the 5th day after toothe extraction and growth rate of osteoid formation was reduced. In the Group 4, necrotized tissue at the outer surface of extraction socket and destructive changes on the alveolar bones were noted on the 10th day. Epithelial fusion was not revealed and large amounts of osteoclast were noted on alveolar bone on the 15th day. Conclusion: The healing process of wound after tooth extraction was retarded by irradiation and especially in the rachitic rats.

• 대한소아치과학회지
• /
• 제24권4호
• /
• pp.795-804
• /
• 1997

Developmental dental morphological anomalies are fusion, gemination, twinning, concrescence and etc. They may cause many problems in conservative, periodontal and esthetic aspects. Fusion is a condition where two separate tooth buds unite at some stage in their development to form a bifid crown. If tooth contact occurs early, at least before the start of calcification, the two teeth may be completely unites to form a single large tooth. If tooth contact occurs after the time when a portion of the tooth crown has completed its formation, there may be union of the roots only. In fusion the dentin is always confluent. Fusion teeth is more common in the deciduous than in the permanent dentition. Fused teeth are relatively rare, and are mostly mandibular anterior teeth. Fusion of normal and supernumerary teeth or between normal teeth may occurs. The exact etiology factor of fusion is unknown, but genetic and environmental factors seems to be related. A variety of complications and subsequent treatments have been suggested on this teeth. Periodontal conditions may arise due to a groove formed at the line of fusion of the two teeth. Crowding or Protrusion with potential for malocclusion or delayed eruption of adjacent teeth. Fusion teeth appear in the anterior region, they usually cause esthetic problems. Treatments vary depending on the problem, the location, and the extent of fusion. Treatment of fused teeth has been reported from endodontic, orthodontic, periodontic, surgical and multidisciplinary. This report presents the esthetic improvements by separation of two clinical crowns. Bone reduction or endodontic treatments are not required.

• International Journal of Oral Biology
• /
• 제45권4호
• /
• pp.190-196
• /
• 2020

Several factors, including genetic and environmental insults, impede protein folding and secretion in the endoplasmic reticulum (ER). Accumulation of unfolded or mis-folded protein in the ER manifests as ER stress. To cope with this morbid condition of the ER, recent data has suggested that the intracellular event of an unfolded protein response plays a critical role in managing the secretory load and maintaining proteostasis in the ER. Tauroursodeoxycholic acid (TUDCA) is a chemical chaperone and hydrophilic bile acid that is known to inhibit apoptosis by attenuating ER stress. Numerous studies have revealed that TUDCA affects hepatic diseases, obesity, and inflammatory illnesses. Recently, molecular regulation of ER stress in tooth development, especially during the secretory stage, has been studied. Therefore, in this study, we examined the developmental role of ER stress regulation in tooth morphogenesis using in vitro organ cultivation methods with a chemical chaperone treatment, TUDCA. Altered cellular events including proliferation, apoptosis, and dentinogenesis were examined using immunostaining and terminal deoxynucleotidyl transferase dUTP nick end labeling assay. In addition, altered localization patterns of the formation of hard tissue matrices related to molecules, including amelogenin and nestin, were examined to assess their morphological changes. Based on our findings, modulating the role of the chemical chaperone TUDCA in tooth morphogenesis, especially through the modulation of cellular proliferation and apoptosis, could be applied as a supporting data for tooth regeneration for future studies.

• 치위생과학회지
• /
• 제15권3호
• /
• pp.295-300
• /
• 2015

치주염을 유발한 쥐 치아의 근심면에서 상아질파괴세포와 뼈파괴세포의 형성을 비교하였다. 뼈파괴세포는 치주염 유발 후 3일까지 증가한 후 감소하였으나 상아질파괴세포는 치주염 유발 10일까지 서서히 증가하였으며 치주염 유발 전과 후의 상아질파괴세포의 수는 뼈파괴세포보다 적었다. 또한 치근 흡수는 상아질파괴세포가 증가함에 따라 증가하였다. 이들 결과는 치주염 시 상아질파괴세포 형성도 뼈파괴세포처럼 증가하나 뼈파괴세포보다 서서히 약하게 진행됨을 시사한다. 본 연구에서 사용한 동물 모델과 연구 결과는 치주염에서 상아질파괴세포와 뼈파괴세포의 형성이 차이가 있음을 제시하는 최초 보고이며, 이들 세포의 형성 기전의 차이를 규명하는 앞으로의 연구에 유용한 자료로 이용될 수 있을 것으로 판단한다.

• 대한소아치과학회지
• /
• 제29권4호
• /
• pp.607-617
• /
• 2002

연령과 치아 발육상태 단계와의 상관관계, 치아의 발육에 따른 치아의 이동상태를 평가하기 위하여 최근 5년 이내에 경북대학교 병원에 내원한 아동(남아 446명, 여아 326명)의 파노라마 방사선사진을 대상으로 하여, Moorrees의 기준에 의하여 하악 영구치아의 발육단계를 평가한 후, 발육단계와 연령, 치조골내 치아의 위치를 평가하여 다음과 같은 결론을 얻었다. 치아의 발육시기는 치관이 완료될 때까지 남, 여의 차이가 없었으나, 치근형성이 되면서 부터는 남아보다 여아에서 더 빨리 발육되는 경향을 나타내었다. 치관형성의 완료시점의 평균연령은 남아 여아 각각에서 중절치 3.71, 4.05세, 측절치 4.44, 4.60세, 견치 5.35, 5.11세, 제1소구치 6.62, 6.36세, 제2소구치 7.36, 7.17세, 제1대구치 3.51, 3.69세, 제2대구치 7.90, 7.64세 이었고, 치근단이 폐쇄되기 전단계인 $A_{1/2}$는 중절치 8.70, 8.18세, 측절치 9.55, 8.99세, 견치 12.48, 11.60세, 제1소구치 12.30, 12.01세, 제2소구치 12.19, 12.26세, 제1대구치 912, 8.87세, 제2대구치 12.59, 12.45세 이었다. 치조골내의 교두점 위치는 치관형성 완료시까지는 거의 변화가 없었으나, 치근이 형성됨에 따라 빠르게 교합평면을 향해 이동하였고, 치근형성 완료단계(Rc)에서 다시 움직임 없이 정체되었다. 치근단의 위치는 치관형성 시작부터 치근 1/4 형성 시까지 일정한 위치에 유지되었으나, 그 후에 급격하게 교합면 쪽으로 이동하였고, 치근 3/4 형성시점부터 비교적 일정한 위치에 유지되었다. 치아의 석회화가 시작되는 초기의 치배 위치는 견치가 가장 하방에 위치하였으며, 그 다음이 제2소구치, 제1소구치, 측절치 제2대구치, 제1대구치 순이었고, 중절치가 가장 상방에 위치하였다.