• 구강회복응용과학지
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• 제31권4호
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• pp.378-386
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• 2015

피개 의치는 의치의 안정과 유지력 증가라는 장점을 갖지만 지대치가 우식 또는 치주질환에 이환되기 쉬우며 의치의 두께가 얇아짐으로써 의치가 파절되기 쉽다는 단점도 갖고 있다. 자성 어태치먼트 피개 의치는 수직적 유지력은 크지만 수평적 유지력은 작으므로 지대치나 임플란트에 덜 위해한 힘을 가하며, 다른 기계적 유지장치에 비해 마모나 파손 등이 적다는 장점이 있다. 피개 의치에서 나타나는 의치의 파절은 의치상의 두께가 얇아져서 발생하기도 하지만, 연조직과 경조직, 임플란트와 자연치의 압하량 차이로 인해 발생하기도 한다. 이를 보상하기 위해 silicone ball이 자석 안에 삽입되어있는 자성 어태치먼트가 개발되었으며, 이를 이용해 피개 의치를 제작한 증례에서 우수한 결과가 나타나 보고하고자 한다.

• 대한소아치과학회지
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• 제30권3호
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• pp.465-470
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• 2003

소아에서 영구 전치부에 강한 외상이 가해지는 경우 단순한 수평파절보다는 비스듬한 수직-수평파절을 보이는 경우가 많으며 파절선이 치은연하로 위치되는 경우도 많은데 그러한 경우 최근에 의도적 재식술을 이용한 치료가 많이 시도되고 있다. 파절치를 탈구시킨 후 순설측을 뒤바꿔서 재식할 경우치근의 방향 차이로 인하여 발치와에서 상방으로 위치되면서 치관의 길이를 증가시킬 수 있으며 파절선을 순측에 위치시켜 시야확보를 용이하게 할 수 있다. 본 증례에서는 치아외상으로 상악 중절치가 치관-치근 파절된 혼합치열기 환아에서 파절치를 $180^{\circ}$ 회전시켜 의도적 재식술을 시행하여 치료한 후 양호한 결과를 얻었다. 이에 예전의 치료방법과 더불어 회전을 이용한 의도적 재식술은 치관-치근 파절치의 또다른 치료 방법이 되리라 사료된다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권3호
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• pp.186-199
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• 2012

Purpose: Single implants, of which screw loosening has been observed frequently, presents problems such as fixtures fractures, marginal bone loss, and inflammation of the soft tissue around the implant. However, the single implant is more conservative, cost effective, and predictable compared to the 3 unit bridge with respect to the long-term outcome. This study evaluated the survival rate as well as future methods aimed at increasing the survival rate in single implants in posterior teeth. Methods: Among the implants placed in the Dankook University Dental Hospital department of Oral & Maxillofacial surgery from January 2001 to June 2008, 599 implants placed in the maxillar and mandibular posterior were evaluated retrospectively. Survival rates were investigated according to implant location, cause of tooth loss, gender, age, general disease, fixture diameter and length, surface texture, implant type and shape, presence of bone graft, surgery stage, surgeons, bone quality and opposite teeth. Results: Out of 599 single implants in posterior teeth, 580 implants survived and the survival rate was 96.8%. The difference in survival rate was statistically significant according to the implant location. The survival rate was low (84.2%) in implants exhibiting a wide diameter (${\geq}5.1mm$) and the surface treated by the acid etching group demonstrated a significantly lower survival rate (91.1%). One stage surgical procedure, which implemented a relatively better bone quality survival rate (100%), was higher than the two stage surgical procedure (96.1%). The survival rate of type IV bone quality (75%) was significantly lower than the other bone quality. Conclusion: Single posterior teeth implant treatments should use an improved surface finishing fixture as well as careful and safe procedures when performing implant surgery in the maxilla premolar and molar regions since bone quality is poor.

• The Journal of Advanced Prosthodontics
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• 제4권1호
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• pp.37-42
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• 2012

PURPOSE. The influence of the modified process in the fiber-reinforced post and resin core foundation treatment on the fracture resistance and failure pattern of premolar was tested in this study. MATERIALS AND METHODS. Thirty-six human mandibular premolars were divided into 4 groups (n = 9). In group DCT, the quartz fibre post (D.T. Light-post) was cemented with resin cement (DUO-LINK) and a core foundation was formed with composite resin (LIGHT-CORE). In group DMO and DMT, resin cement (DUO-LINK) was used for post (D.T. Lightpost) cementation and core foundation; in group DMO, these procedures were performed simultaneously in one step, while DMT group was accomplished in separated two steps. In group LCT, the glass fiber post (LuxaPost) cementation and core foundation was accomplished with composite resin (LuxaCore-Dual) in separated procedures. Tooth were prepared with 2 mm ferrule and restored with nickel-chromium crowns. A static loading test was carried out and loads were applied to the buccal surface of the buccal cusp at a 45 degree inclination to the long axis of the tooth until failure occurred. The data were analyzed with MANOVA (${\alpha}$= .05). The failure pattern was observed and classified as either favorable (allowing repair) or unfavorable (not allowing repair). RESULTS. The mean fracture strength was highest in group DCT followed in descending order by groups DMO, DMT, and LCT. However, there were no significant differences in fracture strength between the groups. A higher prevalence of favorable fractures was detected in group DMT but there were no significant differences between the groups. CONCLUSION. The change of post or core foundation method does not appear to influence the fracture strength and failure patterns.

• Imaging Science in Dentistry
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• 제54권2호
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• pp.139-145
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• 2024

Purpose: This study examined the influence of a metal artifact reduction (MAR) tool, sharpening filters, and their combination on the diagnosis of vertical root fracture (VRF) in teeth with metallic posts using cone-beam computed tomography (CBCT). Materials and Methods: Twenty single-rooted human premolars - 9 with VRF and 11 without - were individually placed in a human mandible. A metallic post composed of a cobalt-chromium alloy was inserted into the root canal of each tooth. CBCT scans were then acquired under the following parameters: 8 mA, a 5×5 cm field of view, a voxel size of 0.085 mm, 90 kVp, and with MAR either enabled or disabled. Five oral and maxillofacial radiologists independently evaluated the CBCT exams under each MAR mode and across 3 sharpening filter conditions: no filter, Sharpen 1×, and Sharpen 2×. The diagnostic performance was quantified by the area under the receiver operating characteristic curve (AUC), sensitivity, and specificity. These metrics were compared using 2-way analysis of variance with a significance level of α=5%. Intra- and inter-examiner agreement were assessed using the weighted kappa test. Results: Neither MAR nor the application of sharpening filters significantly impacted AUC or specificity (P>0.05). However, sensitivity increased when MAR was combined with Sharpen 1× and Sharpen 2× (P=0.015). The intra-examiner agreement ranged from fair to substantial (0.34-0.66), while the inter-examiner agreement ranged from fair to moderate (0.27-0.41). Conclusion: MAR in conjunction with sharpening filters improved VRF detection; therefore, their combined use is recommended in cases of suspected VRF.

• 대한기계학회논문집A
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• 제25권6호
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• pp.972-979
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• 2001

Tool fracture index(TFI) was developed in order not only to detect tool fracture but also to predict the amount of tool fracture in face milling. TFI is calculated by using peak-to-valley values of cutting force acting on teeth and their ratio between the adjacent teeth. When the tool fractures, a large value of TFI proportional to the amount of tool fracture was obtained periodically and decreased gradually. It was found that TFI is independent of cutter runout and it almost does not vary during transient cutting such as cutting condition change during machining. The threshold of tool fracture can be analytically determined by TFI developed in this paper, because the magnitude of TFI was shown to be dependent on the ratio of the amount of tool fracture to feed per tooth and immersion ratio. It was possible to predict the amount of tool fracture in experiments by using the proposed TFI.

• 대한치과교정학회지
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• 제21권2호
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• pp.259-272
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• 1991

Orthodontic traction has been suggested as the treatment of choice for intrusive luxation injuries. Prior research has shown orthodontic forces to be ineffective in the presence of ankylosis or in cases with zero mobility following the injury. If orthodontic traction is to be effective, it must be initiated prior to the onset of ankylosis. The purpose of this study was to describe the effects of intrusive luxation at various times following the injury, and to determine the time of the onset of ankylosis, and to examine what effect immediate partial luxation has on the onset of ankylosis. Eight young mongrel dogs were utilized for this study. Intrusive luxation was produced with an axial impact using a gravity hammer and a specially designed holding device on 4 teeth (2 max. and 2 man. first premolars) in each dog. The teeth were intruded approximately 3-4mm in an axial direction. One maxillary and one mandibular premolars were partially luxated with the other two teeth being untouched. Pre and posttrauma tooth position was documented with plaster models and radiographs taken with an individualized X-ray jig. Dogs were sacrificed immediately following the injury and at 1, 2, 4, 7, 10, 14 and 21 days respectively. Tetracycline was administered as a vital bone marker 24 hours before sacrifice. Block sections of the tooth and alveolus were prepared for decalcified and non decalcified histologic sections. The effects of traumatic intrusion were analyzed by means of model casts, radiographs, tetracycline bone marking and histologic preparations. The results obtained were as follows: 1. The animal sacrificed immediately following the injury displayed alveolar fractures, torn periodontal ligaments, and areas of direct tooth-bone contact. 2. The odontoblastic layer of the pulp was disorganized as early as 24 hours after the injury. 3. Bony remodeling was noted at 4 days along with active surface resorption. 4. Ankylosis was first seen 7 days after the injury. 5. Osteogenesis in the dentin (thick tetracycline bands) was observed 7 days after the injury. 6. There was no progressive root resorption and ankylosis where the periodontal ligament has been healed. 7. The Luxated group showed significantly more root resolution and ankylosis than the Nonluxated group with increased observation periods. The results suggest that ankylosis may occur within the first week following the injury, and hence orthodontic traction should be initiated as soon after the injury as possible.

• 대한소아치과학회지
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• 제34권1호
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• pp.156-161
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• 2007

소아치과 임상에서는 외상성 손상에 의하거나 발치 도중 우발적으로 유치의 치근이 파절되는 경우가 종종 있다. 이런 경우 임상의들은 치근 파절편을 발치할지, 남겨둘지에 대해 간혹 고민하게 된다. 이같은 상황에서 잔근이나 파절편의 발치 시도가 계승치 배를 손상시킬 우려가 있을 경우에는 일반적으로 치근 파절편을 남겨두는 것이 추천되고 있다. 본 연구는 유치 잔근이나 파절편을 술자 의도적으로 잔존시킨 경우, 계승치의 맹출경로에 장애를 가하지 않고 소멸될 것인지의 예후를 확인해 볼 목적으로 잔근이나 치근 파절편을 의도적으로 남긴 3세 8개월${\sim}6$세 1개월 어린이 6명을 대상으로 $7{\sim}37$개월 동안 $2{\sim}3$개월 주기의 내원을 통하여 임상검사와 방사선검사를 시행하고 예후를 장기 관찰하였다. 관찰 결과, 5 증례에서 치근측 파절편은 생리적인 흡수과정을 통하여 크기가 축소되거나 소멸되었고, 1 증례에서는 계승치와 함께 밀려 출은하였으며 계승치의 맹출을 현저하게 지장을 초래한 경우는 나타나지 않았다. 본 관찰을 통하여 치조골 내에 남은 유치근 파절편이 계승치배에 근접한 경우, 이를 무리하게 발치하려 시도하기보다는 치배의 손상 가능성을 고려하여 잔존시키고 주기적인 검진을 통해 흡수 여부를 판단하며 예후 관리를 하는 방법의 타당성을 확인할 수 있었다.

• 구강회복응용과학지
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• 제35권4호
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• pp.206-213
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• 2019

목적: 굴곡파절의 대부분 연구들이 협측에 한정되어있다. 본 연구에서는 상악 구치부에서 구개측 굴곡파절의 빈도 조사를 통해 굴곡파절의 원인을 분석해보고자 한다. 연구 재료 및 방법: 총 3193개의 상악 구치를 대상으로 조사를 진행하였다. 구내 관찰과 모형 관찰, 그리고 모형 스캔을 통해 제작된 가상 모형을 관찰하는 방법으로 조사를 진행하였다. 그 결과를 치아, 연령, 성별, 악궁에 따라 분류하였다. 통계적 유의성의 평가를 위해 Chi-square test를 시행하였다(α = 0.05). 결과:상악 소구치(6.8%)보다 대구치(10.8%)에서 구개측 굴곡파절이 높은 빈도로 관찰되었고, 그중 제1대구치(39.1%)에서 가장 높은 빈도로 관찰되었다. 연령이 증가할수록 구개측 굴곡파절이 높은 빈도로 관찰되었으며 이는 통계적으로 유의성이 있었다(P < 0.05). 구개측 굴곡파절의 빈도는 성별에 따른 차이에서는 통계적으로 유의성이 없었으며(P > 0.05), 악궁에 따른 차이에서는 좌측에서 더 높은 빈도로 나타났고 통계적으로 유의성이 있었다(P < 0.05). 결론: 상악 구치에서 구개측 굴곡파절은 상악 제1대구치에서 높은 빈도로 관찰되었고, 연령의 증가에 따라 증가하는 양상을 보였다. 이와 같은 결과는 굴곡파절의 가장 주된 원인이 교합력임을 의미한다.

• 대한소아치과학회지
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• 제36권2호
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• pp.288-292
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• 2009

치관-치근 파절(crown-root fracture)은 법랑질, 상아질, 백악질에 파급된 파절이며 치수노출을 수반하는 것과 수반하지 않는 것이 있다. 치근부위만 파절된 경우와 달리 치관-치근 파절의 경우 치수와 치주조직을 통해 세균감염이 발생하기 때문에 치유를 기대하기 힘들다. 파절은 치근을 따라 다양한 부위에서 일어나기 때문에 치료방법은 파절 정도에 따라 결정된다. 치근의 파절선이 치관부에 근접 한 경우 느슨한 치아 파절편을 제거 한 후, long junctional epithelium이 형성되도록 치은을 노출된 상아질에 맞게 적합시키거나, 외과적으로 파절 부위를 노출시키거나, 교정적 또는 외과적으로 치아를 정출시키는 방법 등을 고려해 볼 수 있지만 파절선이 깊은 경우 발치가 일반적이다. 그러나 최근 논문에서 수직 치관-치근 파절된 치아에 대해 발치대신 레진으로 파절선을 수복한 후 재식하여 성공한 사례가 발표되었다. 이 방법으로 치아를 보존할 수 있으며 이러한 방법이 전치 부에서는 예후가 좋다고 보고되었다. 본 증례에서는 외상으로 인하여 상악중절치의 치관-치근 파절이 발생한 10세 환아에서 해당 치아를 발치하여 레진으로 파절부위를 재부착한 후 재식하였다. 그러나 18개월간 주기적으로 관찰한 결과 문헌에서와 같은 좋은 결과를 나타내지는 않았다.