• Journal of Periodontal and Implant Science
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• 제25권1호
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• pp.67-75
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• 1995

The progress of periodontal disease and the wound healing process after treatment result in alveolar bone bone change. So, detection of it is very important in the diagnosis and the radiograph of periodontal disease. Various effects have been made to assess the subtle alveolar bone change and digital subtraction radiography (DSR) has been reported to be the best method in evaluating it qualitatively and quantitatively. The present study was performed to estimate the detectable alveolar bone change qualitatively with digital subtraction radiography. For the in vitro study, 10 intraoral standard radiographs were taken from porcine dry mandible which a rectangular cortical bone chip of 0.1mm to 1.0mm thickness with 0.1mm increment was attached on the buccal surface. The radiographs without and with bone plates were reviewed at the same time by 10 observers and requested to detect the presence of cortical bone plates. Digital Subtraction radiograph was reviewed subsequently by using the DSR system(digital converter-256 grey-levels,DT 2851,Data Translation Co., U.S.A;IBM 386 ; CCD camera, FOTOVIX, Tamrom Co., Japan). The detectable thickness of cortical bone plate was O.4mm on the intraoral radiograph and 0.2mm on the subtaction images. For the human study, radiographs were taken from patients by using intraoral film holding device and aluminum reference wedge before and 3 month after bone graft and 1 week after osteoplasty. The grey level change was estimated in the subtraction images and calculated to aluminum equivalent thickness. The grey level of the grafted site was higher that that of healthy controls. Average grey levels of change on healthy controls were O.48mm aluminum equivalent. However, the amount of changes in grafted sites were 1.87mm aluminum thickness equivalent and in the site of osteoplasty were -1.49mm aluminum thickness equivalent. In conclusion, digital subtraction radiography was more effective in detecting as subtle change of alveolar bone than intraoral standard radiography. With the aid of quantitative analysis of digital subtraction radiography, alveolar bone resorption of apposition can be estimated during diagnosis and treatment of periodontally diseased patients.

• The Journal of Advanced Prosthodontics
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• 제5권4호
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• pp.494-501
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• 2013

PURPOSE. The purpose of this study was to provide an actual guideline in determining the shape, diameter, and position of the implant in immediate implantation by the measurement of the thickness of facial and palatal plate, the thickness of cortical bone on the facial and palatal plate, the diameter of the root, and the distance between the roots in the cadavers. MATERIALS AND METHODS. The horizontal sections of 20 maxillae were measured and analyzed to obtain the average values. Resin blocks were produced and cut serially at 1 mm intervals from the cervical line to the root apex. Images of each section were obtained and the following measurements were performed: The thickness of the facial and palatal residual bone at each root surface, the thickness of the facial and palatal cortical bone at the interdental region, the diameter of all roots of each section on the faciopalatal and mesiodistal diameter, and the interroot distance. Three specimens with measurements close to the average values were chosen and 3-dimensional images were reconstructed. RESULTS. The thickness of the facial and palatal cortical bone at the interdental region in the maxilla, the buccal cortical bone was thicker in the posterior region compared to the anterior region. The interroot distance of the alveolar bone thickness between the roots increased from anterior to posterior region and from coronal to apical in the maxilla. CONCLUSION. In this study, the limited results of the morphometric analysis of the alveolar ridge using the sections of maxilla in the cadavers may offer the useful information when planning and selecting optimal implant for immediate implantation in the maxilla.

• Imaging Science in Dentistry
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• 제52권3호
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• pp.267-273
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• 2022

Purpose: The aim of this study was to assess the influence of kilovoltage- peak (kVp) and the metal artifact reduction (MAR) tool on the detection of buccal and lingual peri-implant dehiscence in the presence of titanium-zirconia (Ti-Zr) and zirconia (Zr) implants in cone-beam computed tomography (CBCT) images. Materials and Methods: Twenty implant sites were created in the posterior region of human mandibles, including control sites (without dehiscence) and experimental sites (with dehiscence). Individually, a Ti-Zr or Zr implant was placed in each implant site. CBCT scans were performed using a Picasso Trio device, with variation in the kVp setting (70 or 90 kVp) and whether the MAR tool was used. Three oral radiologists scored the detection of dehiscence using a 5-point scale. The area under the receiver operating characteristic (ROC) curve, sensitivity, and specificity were calculated and compared by multi-way analysis of variance (α=0.05). Results: The kVp, cortical plate involved (buccal or lingual cortices), and MAR did not influence any diagnostic values (P>0.05). The material of the implant did not influence the ROC curve values(P>0.05). In contrast, the sensitivity and specificity were statistically significantly influenced by the implant material (P<0.05) with Zr implants showing higher sensitivity values and lower specificity values than Ti-Zr implants. Conclusion: The detection of peri-implant dehiscence was not influenced by kVp, use of the MAR tool, or the cortical plate. Greater sensitivity and lower specificity were shown for the detection of peri-implant dehiscence in the presence of a Zr implant.

• 대한치과교정학회지
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• 제44권4호
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• pp.217-225
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• 2014

Single-tooth implantation has become a common treatment solution for replacement of a root-fractured maxillary incisor in adults, but the long-term esthetic results can be unfavorable due to progressive marginal bone loss, resulting in gingival recession. In this case report, a maxillary central incisor with a root fracture in its apical one-third was orthodontically extruded and extracted in a 21-year-old female. Implant surgery was performed after a 3-month healing period, and the final crown was placed about 12 months after extraction. After 12 years, favorable osseous and gingival architectures were visible with adequate bone height and thickness at the buccal cortical plate, and no gingival recession was seen around the implant-supported crown. Although modern dentistry has been shifting toward simplified, clinical procedures and shorter treatment times, both general dentists and orthodontists should be aware of the possible long-term esthetic advantages of orthodontic extrusion of hopelessly fractured teeth for highly esthetically demanding areas and should educate and motivate patients regarding the choice of this treatment solution, if necessary.

• 대한치과의사협회지
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• 제53권8호
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• pp.545-557
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• 2015

The modified ridge splitting/expansion technique combined with guided bone regeneration (GBR) for implant surgery is used to expand the narrow and atrophied edentulous alveolar ridge. Also, the simultaneous implant placement after ridge splitting/expansion technique can reduce the treatment and healing time. This case report includes three patients with a narrow edentulous alveolar ridge of the 2 to 4mm. All three patients underwent a fracture of thin buccal cortical bone plate, and these defects were corrected by the use of the guided bone regeneration (GBR). After 7 to 18 months, all surgical area was stable, and all implant showed a good healing state on the clinical and radiographic examination. In conclusion, though this surgical method is technique sensitive, the modified ridge splitting/expansion technique combined with GBR for implant surgery is recommended for a horizontal augmentation in the narrow edentulous alveolar ridge.

• 구강회복응용과학지
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• 제36권2호
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• pp.88-94
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• 2020

목적: 본 연구는 한국인에서 상악 전치의 치근 위치를 시상면에서 분석하고, 분류에 따른 빈도를 보고함으로써 즉시 식립 임플란트를 위한 방사선학적 자료를 수집하기 위함이다. 연구 재료 및 방법: 콘빔형 전산화단층영상(cone-beam CT)을 촬영한 환자 중 연구 기준에 적합한 120명(남성 60명, 여성 60명)을 대상으로 후향적 분석을 시행하였다. 축의 방향설정을 시행한 후에, 상악 전치부 치아와 치조골 사이의 관계에 대한 시상 치근 위치를 분석하였다. 치근이 치조골의 협측, 중앙, 구개측으로 위치한 경우 각각 Class I, II, III로 분류하였으며, 치근이 협측과 구개측 모두에서 피질골판에 2/3 이상 닿아있는 경우에는 Class IV로 하였다. 다음으로, 치아의 장축과 치조골의 장축 사이의 각도를 측정하였다. 기술적 분석 및 Kruskal-Wallis 분석을 시행하였으며, 치아의 위치 및 분류에 따른 시상각을 비교하였다. 결과: 상악 전치부의 시상 치근 위치에 대한 빈도분석 결과, Class I은 81.1%, Class II는 10.3%, Class III는 1.9%, 그리고 Class IV는 6.7%로 나타났다. 상악 전치부의 77.5%에서 시상각이 20도 이하로 나타났다. 그러나 견치의 경우, 42.7%에서 20도 이상의 시상각을 보였다. 분류에 따라서는 Class I (16.19)에서 Class II (8.72) 및 Class III (9.93)에 비해 통계학적으로 유의하게 높은 시상각을 보였으며, Class IV (3.79)에서 낮았다. 결론: 본 제한된 연구의 결과를 근거로, 상악 전치의 치근은 일반적으로 협측 치조골에 가깝게 위치하고 있으나, 일부 치아는 매우 얇은 치조골을 가지고 있으며, 30도 이상의 큰 시상각을 보였다. 따라서 적절한 치과 임플란트 치료 계획 수립을 위해 시상 치근 위치 및 시상각에 대한 cone-beam CT 분석이 필요할 것이다.