• Imaging Science in Dentistry
• /
• 제33권1호
• /
• pp.35-41
• /
• 2003

Purpose: To aid in determining the volume of graft bone required before a maxillary sinus lift procedure and compare the alveolar bone height measurements taken by panoramic radiographs to those by CT images. Materials and Methods : Data obtained by both panoramic radiographs and CT examination of 25 patients were used in this study. Maxillary sinus volumes from the antral floor to heights of 5 mm, 10 mm, 15 mm, and 20 mm, were calculated. Alveolar bone height was measured on the panoramic images at each maxillary tooth site and corrected by magnification rate (PBH). Available bone height (ABH) and full bone height (FBH) was measured on reconstructed CT images. PBH was compared with ABH and FBH at the maxillary incisors, canines, premolars, and molars. Results: Volumes of the inferior portion of the sinuses were 0.55 ± 0041 ㎤ for 5 mm lifts, 2.11 ± 0.68 ㎤ for 10 mm, 4.26 ± 1.32 ㎤ for 15 mm, 6.95 ± 2.01 ㎤ for 20 mm. For the alveolar bone measurement, measurements by panoramic images were longer than available bone heights determined by CT images at the incisor and canine areas, and shorter than full bone heights on CT images at incisor, premolar, and molar areas (p<0.001). Conclusion: In bone grafting of the maxillary sinus floor, 0.96 ㎤ or more is required for a 5 mm-lift, 2.79 ㎤ or more for a 10 mm-lift, 5.58 ㎤ or more for a 15 mm-lift, and 8.96 ㎤ or more for a 20 mm-lift. Maxillary implant length determined using panoramic radiograph alone could result in underestimation or overestimation, according to the site involved.

• Imaging Science in Dentistry
• /
• 제35권2호
• /
• pp.77-82
• /
• 2005

Purpose : To reveal what is the distinct differential diagnostic differences between unicystic ameloblastoma and solid or multicystic ameloblastoma. Materials and Methods : 56 cases of ameloblastoma were retrospectively reviewed and evaluated among the patients who had taken CT scans at the department of Oral & Maxillofacial Radiology in Yonsei University Dental Hospital from January 1996 to December 2003. Results : In 56 cases, 21 cases $(37.5\%)$ were unicystic ameloblastoma, 35 cases $(62.5\%)$ were solid or multicystic ameloblastoma. Only 1 case $(4.8\%)$ of unicystic ameloblastoma and 4 cases $(11.4\%)$ of solid or multicystic ameloblastoma were occurred in maxilla. 13 cases $(61.9\%)$ of unicystic ameloblastoma were observed as unilocular, and 8 cases $(38.1\%)$ as lobulated. 5 cases $(14.3\%)$ of solid or multicystic ameloblastoma were observed as unilocular, 13 cases $(37.1\%)$ as lobulated, and 17 cases $(48.6\%)$ as multilocular. Tn the results from the measurements after correction of the buccolingual widths and heights to the mesiodistal lengths, there is a statistically significant difference between unicystic ameloblastoma and solid or multicystic ameloblastoma in ANCOVA test (p<0.05). Hounsfield units in the lesion were $24.9{\pm}8.8\;HU$ in unicystic ameloblastoma, $31.2{\pm}11.5\;HU$ in solid or multicystic ameloblastoma. There is no statistically significant difference (p>0.05). Conclusion : Characteristic differences between unicystic ameloblastoma and solid or multicystic ameloblastoma is that there is higher prevalence of solid or multicystic ameloblastoma that have lobulated or multilocular patterns. To measure the Hounsfield units in the lesion is helpful, but it is not a differential diagnostic point between unicystic ameloblastoma and solid or multicystic ameloblastoma.

• Imaging Science in Dentistry
• /
• 제46권2호
• /
• pp.87-92
• /
• 2016

Purpose: The aim of this study was to assess and compare the diagnostic performance of panoramic and occlusal radiographs in detecting submandibular sialoliths. Materials and Methods: A total of 40 patients (20 cases and 20 controls) were included in this retrospective study. Cases were defined as subjects with a submandibular sialolith confirmed by computed tomography (CT), whereas controls did not have any submandibular calcifications. Three observers with different expertise levels assessed panoramic and occlusal radiographs of all subjects for the presence of sialoliths. Intraobserver and interobserver agreement were assessed using the kappa test. Sensitivity, specificity, accuracy, positive and negative predictive values, and the diagnostic odds ratio of panoramic and occlusal radiographs in screening for submandibular sialoliths were calculated for each observer. Results: The sensitivity and specificity values for occlusal and panoramic radiographs all ranged from 80% to 100%. The lowest values of sensitivity and specificity observed among the observers were 82.6% and 80%, respectively (P=0.001). Intraobserver and interobserver agreement were higher for occlusal radiographs than for panoramic radiographs, although panoramic radiographs demonstrated a higher overall accuracy. Conclusion: Both panoramic and occlusal radiographic techniques displayed satisfactory diagnostic performance and should be considered before using a CT scan to detect submandibular sialoliths.

• 대한치과보철학회지
• /
• 제39권3호
• /
• pp.273-281
• /
• 2001

Digital subtraction radiography may be one of the most precise and noninvasive methods for assessing subtle density changes in peri-implant bone, providing additional diagnostic information on implant tissue integration in overall maintenance. The aims of this study were to evaluate density changes after first, second surgery of dental implant and to measure the amount of marginal bone loss 9 months after second surgery using digital subtraction radiography. Bone change around 30 screw-shaped implants in 16 patients were assessed on radiographs. 17 Branemark implants of 3.75mm in diameter(Nobel Biocare, Goteborg, Sweden), 2 Branemark implants of 5.0mm in diameter, 11 $Replace^{TM}$ implants of 4.3mm in diameter(Nobel Biocare, Goteborg, Sweden) were used. To standardize the projection geometry of serial radiographs of implants, customized bite block was fabricated using XCP film holder(Rinn Corporation, Elgin, IL.) with polyether impression material of Impregum(ESPE, Germany) and direct digital image was obtained. Qualitative and quantitative changes on radiographs were measured with Emago software(The Oral Diagnostic System, Amsterdam, Netherlands). The results were as follows: 1. The peri-implant bone density of 69.2% implants did not change and the peri-implant bone density of 30.8% implants decreased after 3 months following first surgery. 2. The crestal bone density of 53.9% implants decreased first 3 months after second surgery. The crestal bone density of 58.8% implants increased 9 months after second surgery. No density change was observed around the midportion of the implants after second surgery, 3. The amount of marginal bone loss between different kinds of implants showed no statistically significant differences (p>0.05). 4. More than 90% of total marginal bone loss recorded in a 9-month period occurred during the first 3 months.

• 대한치과보철학회지
• /
• 제38권6호
• /
• pp.800-805
• /
• 2000

In an effort to facilitate fabrication procedure of all ceramic crowns, a novel preparation method for all ceramic crown using alumina tape was developed. The alumina tape having a uniform thickness was cast by using Doctor blade method. The physical properties of newly introduced alumina tape has biaxial flexure strength of $500\sim600MPa$. The value of toughness is $3.18\sim3,28MPa.m^{1/2}$ which corelates with fracture and the linear shrinkage rate of the alumina tape is 0.44% during core production. The marginal fitness of the alumina tape all-ceramic restoration with $90{!`}$shoulder margin had average marginal discrepancy at $78.3{\S}$ > and average marginal gap at $44.4{\S}$ >. At the marginal preparation of $135{!`}$deep chamfer, the average marginal discrepancy at $82.1{\S}$ > and the average marginal gap at $40.2{\S}$ > had been reported. This fabrication procedure of all ceramic crowns with alumina tapes is easier and less technical sensitive for dental technicians. After restoration with new all ceramic crowns we followed the patients 2 years later, there were no complications as porcelain fractures or periodontal disease. We had good esthetic clinical results with new all ceramic crowns.

• Journal of Periodontal and Implant Science
• /
• 제38권2호
• /
• pp.225-230
• /
• 2008

Purpose: Many clinical studies have reported that higher success rates are achieved with teeth that have immature roots than other autotransplanted teeth that have more immature root. However, based on date published recently, the success rate of autotransplantation of teeth with complete root formation was higher. The purpose of this study was to examine the long term(2 to 6 years follow-up) success rate of autotransplantation of third molar with complete root formation and to discuss some conditions and prerequisites for success. Materials and Methods: 26 sites of 24 patients aged 26 to 55 (mean age 40.8) were autotransplanted with third molars with complete root formation. These cases were followed for 2 to 6 years after surgery. The success criteria included (1) no discomfort during functioning (2) absence of progressive root resorption and alveolar bone resorption. Result: Of 26 teeth 5 teeth were failed, therefore success rate is 81%(21/26 teeth). The results suggested that higher success rate is acquired from (1) extraction socket due to dental caries (2) mandibular recipient site (3) patient younger than 40 years old. Autotransplantation of third molar to replace molars with advanced periodontal disease also showed considerably high success rate(84%). Conclusion: With appropriate case selection, autotransplantation of third molar with complete root formation remains a viable alternative for replacing a missing molar tooth.

• 대한소아치과학회지
• /
• 제25권3호
• /
• pp.635-648
• /
• 1998

The clinical use of fluoride with a well known osteogenic action in osteoporotic patients is rational, because this condition is characterized by impaired bone formation. However, its anabolic effect has not been demonstrated well in vitro. The purpose of this study was to investigate the effects of sodium fluoride on the physiological role of osteoblastic cell. Osteoblastic cells were isolated from fetal rat calvaria. The results were as follows : 1. Mineralized nodules were shown in osteoblastic cell cultures, which had been maintained in the presence of ascorbic acid and ${\beta}-glycerophosphate$ up to 21 days. When cultures were treated with pulses of 48 hr duration before apparent mineralization was occurring, 2-fold increased in their number was detected. 2. Alkaline phosphatase activity of osteoblastic cells was inhibited by sodium fluoride in dose dependent manner. 3. The effect of sodium fluoride on the osteoblastic cell proliferation was measured by the incorporation of $[^3H]$-thymidine into DNA. As a result, sodium fluoride at $1{\sim}100{\mu}M$ increased the $[^3H]$-thymidine incorporation into DNA in a dose dependent manner. 4. The signaling mechanism activated by sodium fluoride dose-dependently enhanced the tyrosine phosphorylation of the adaptor molecule $Shc^{p66}$ and their association with Grb2, one of earlier events in a MAP kinase activation pathway cascade used by a significant subset of G protein-coupled receptors. 5. The phosphorylation of CREB(cAMP response element binding protein)was inhibited by the sodium fluoride in MC3T3E1 cells. In conclusion, the results of this study suggested that the mitogenic effect of the sodium fluoride in MC3T3E1 cell was stimulated in a dose-dependent manner and suggested "an important role for the interaction between She and Grb2" in controlling the proliferation of osteoblasts.

• 대한소아치과학회지
• /
• 제33권2호
• /
• pp.269-280
• /
• 2006

연구 목적은 근거중심 소아치과학의 개념을 정립하고 그 응용 방법을 모색하는 것이었다. 근거중심 소아치과학의 정의는 '어린이와 청소년의 치과 진료에서 최고의 과학적 연구근거를 소아치과의사의 임상 기술, 그리고 어린이 환자 및 그 보육자의 가치와 통합하는 것'으로 가정하였다. 근거중심 소아치과학의 실행 방법을 조사하였고, 근거중심 소아치과학의 최신 결론을 선별하여 주제별로 정리하였으며, 근거중심 소아치과학 연구의 기본이 되는 체계적 고찰과 임상진료지침의 연구 방법을 분석하고, 개별 연구 방법으로서 무작위 대조 시험 등을 조사하였다. 근거중심 소아치과학이 발전하기 위한 기본 방향으로서, 근거중심 소아치과학의 필요성에 대한 인식 제고와 공감대 형성, 근거중심 소아치과학의 방법에 대한 교육, 소아치과학 문헌의 전산화, 체계적 고찰과 임상진료지침의 지속적 연구 개발 및 보급, 우리나라 소아치과학 근거의 생성, 소아치과 진료환경의 사회적 요인 개선 등이 제안되었다.

• 구강회복응용과학지
• /
• 제31권3호
• /
• pp.231-241
• /
• 2015

환자의 심미적 요구가 증가함에 따라 전치뿐만 아니라 구치부에서도 자연치아와 유사한 색조와 외형을 재현한 보철물에 대한 필요성이 증가하고 있다. 단일 지르코니아와 CAD/CAM 시스템을 통해 이러한 환자의 요구를 만족시키는 보철물 제작이 가능해졌다. 본 증례는 70세 여자환자로 전치부 보철물이 깨져서 보기 싫고 하악 구치부가 없어서 저작이 불편하다는 주소로 내원하였다. 하악 구치의 상실로 교합평면이 붕괴되었으며 과도한 치아 마모 및 수직고경 상실이 관찰되어 치아 상실 부위에 임플란트를 식립하고 수직고경 증가와 함께 지르코니아 고정성 보철물을 이용한 전악 수복 치료를 진행하였다. 치료 후 3년 간 이상적인 교합이 잘 유지되고 기능적, 심미적으로 만족한 결과를 얻었기에 이를 보고하는 바이다.

• 구강회복응용과학지
• /
• 제31권3호
• /
• pp.273-282
• /
• 2015

중심위에서 벗어나 있는 최대교두감합위는 상하악 치아의 조기접촉 및 사면활주의 직접적인 원인이며, 악관절 내장증, 치아마모, 치주질환 등을 일으킬 수 있다. 그러므로 광범위한 보철수복이 필요한 환자에서 중심위와 최대교두감합위의 불일치가 존재하는 경우 반드시 이를 제거하여 생리적인 교합양식을 회복해야 한다. 본 증례의 환자는 초진 시 약 3.5 mm의 사면활주와 다수의 우식 및 중등도의 치주질환을 앓고 있었다. 보철수복을 통해 기능 및 심미성을 회복하는 동시에 중심위와 최대교두감합위를 일치시켜 사면활주를 제거하였으며, ARCUSdigma II와 경두개 방사선 사진을 이용하여 생리적인 위치로 수정된 하악위와 변화된 개폐구 경로를 관찰하였다.