• 치과방사선
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• 제18권1호
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• pp.13-25
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• 1988

Bone destruction was induced experimentally by the insertion of a bit of the arsenic compound into the pulp chambers of the right premolars and the artificial bone defects were produced in the periapical regions of the left premolars in 7 dogs. The serial standardized periapical radiographs using aluminum stepwedge attached to the XCP instruments, and resin bite blocks were taken following insertion of arsenic compound and at 2, 4, 7, 10, 14, 17, 21, 24 and 28 days in case of bone destruction and following bone injury and weekly thereafter for a total of 14 weeks in case of bone formation. The errors of the method were determined with error estimators described by the Duinkerke. All radiographs were evaluated by the visual examination after joint evaluation by three dental radiologists and analysed with densitometer. The following results were obtained; 1. Analysis of the bone destruction process 1) The error of the method in estimating two distances proved to be small (S.D. for the measuring error; 0.04㎜, S.D. for the over-all error; 0.06㎜, S.D. for the positioning error; 0.05㎜) 2) The radiographic changes were observed after 7 days in 6 cases, 4 days in 1 case and 10 days in 1 case by the visual examination. 3) Aluminum equivalent values were diminished after 2 days and the diminution of 0.58±0.19㎜ was demanded to be detected by the visual examination. 2. Analysis of the bone formation process 1) The error of the method in estimating two distances proved to be small (S.D. for the measuring error; 0.03㎜, S.D. for the over-all error; 0.04㎜ S.D. for the positioning error; 0.04㎜) 2) The radiographic changes were observed after 2 weeks in 5 cases and 3 weeks in 2 cases by the visual examination. 3) Aluminum equivalent values were increased after 1 week and the increase of 0.45±0.15㎜ was demanded to be detected by the visual examination. 4) Aluminum equivalent values were increased continuously for 7 or 9 weeks but there as only extremely small change after 10 weeks.

• International Journal of Oral Biology
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• 제40권4호
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• pp.175-182
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• 2015

Previous studies suggested that myelinated axons innervating rat molar pulps undergo morphological changes in their peripheral course. However, little information is available on the morphological feature of the parent axons at the site of origin. We therefore investigated the size of the myelinated parent axons and their morphological features at the proximal sensory root of the trigeminal ganglion by horseradish peroxidase (HRP) injection into rat upper molar pulps and subsequent light and electron microscopy. A total of 248 HRP-labeled myelinated axons investigated were highly variable in the size. Fiber area, fiber diameter, axon area (axoplasm area), axon diameter (axoplasm diameter), and myelin thickness were $11.32{\pm}8.36{\mu}m^2(0.80{\sim}53.17{\mu}m^2)$, $3.99{\pm}1.53{\mu}m(1.08{\sim}9.26{\mu}m)$, $8.70{\pm}6.30{\mu}m^2(0.70{\sim}41.83{\mu}m^2)$, $3.13{\pm}1.13{\mu}m(0.94{\sim}7.20{\mu}m)$ and $0.43{\pm}0.23{\mu}m(0.07{\sim}1.06{\mu}m)$, respectively. The g-ratio (axon diameter / fiber diameter) of the labeled axons was $0.79{\pm}0.05$ (0.61~0.91). Axon diameter was highly correlated with myelin thickness (correlation coefficients, r=0.83) but little correlated with g-ratio (r=-0.33) of individual myelinated parent axons. These results indicate that myelin thickness of the myelinated parent axons innervating rat molar pulps increase with increasing axon diameter, thus maintaining a constant g-ratio.

• 대한임상검사과학회지
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• 제38권1호
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• pp.45-53
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• 2006

Anaerobic black-pigmented bacteria have been implicated in the endodontic infections. This group of microorganisms includes Porphyromonas endodontalis, P. gingivalis, Prevotella intermedia, and Prevotella nigrescens. The organisms display a wide variety of virulence factors that may be pertinent to acute endodontic infections. The aim of this study was to identify P. endodontalis, P. gingivalis, P. intermedia, and P. nigrescens by using the special potency disk test, filter paper spot test, 16S rRNA gene-directed PCR, and API 32A system. Microbial samples were collected from root canals of 33 intact teeth with necrotic pulp and apical periodontitis. Conventional laboratory methods were used to identify the strains of anaerobic black pigmented bacteria. Eighteen out of 33 samples were positive for the growth of black-pigmented bacrteria. Five colonies were cultured from each pure cultured colony from Brucella agar plates. Seventy seven colonies were positive for the growth of black-pigmented bacteria. Thirty three out of 77(42.8%) were identifed as P. nigrescens, 10 out of 77(13%)were P. gingivalis, 6 out of 77(7.8%) were P. endodontalis, 10 out of 77(13%) were P. intermedia. On the contrary the reference strains of P. nigrescens, experimental strains of P. nigrescens were susceptible to kanamycin in the special potency disk test. We concluded that after rapid presumptive identification methods, such as the special potency disk test and filter paper spot test were done, 16S rRNA gene PCR and API 32A test would be accurate detection methods for black-pigemented bacteria.

• 대한소아치과학회지
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• 제39권1호
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• pp.84-89
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• 2012

치근낭은 가장 흔한 치성기원 낭으로 치수감염, 치수실활, 외상으로 인한 이차감염 또는 치아 우식에 의해 발생한다. 보통치근낭은 무증상이나 이차 감염이 발생할 경우 통증, 부종, 발적 등을 유발할 수 있으며, 크기가 커질수록 치근낭은 인접한 신경을 압박하여 안면비대칭 또는 마비증세를 일으킬 수 있다. 치료는 보존적 신경치료 또는 외과적 처치를 요하며, 낭의 크기가 크거나 인접 조직의 침범을 야기할 가능성이 있는 경우에는 낭적출술을 시행해야 한다. 대부분의 증례에서 완벽한 치료가 가능하고 재발율이 낮다. 본 증례의 환아들은 하악전치부 낭을 주소로 내원하여 임상검사에서 일부 하악전치가 괴사되었음을 발견하였으므로 근관치료를 시행한 후 전신마취하에 치근단절제술 및 치근낭 적출술을 시행하였다. 이후 컴퓨터단층촬영을 시행하여 이환부의 골생성 및 재발여부를 관찰하였으며 성공적인 결과를 보였기에 이를 보고하는 바이다.

• 대한소아치과학회지
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• 제38권1호
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• pp.82-87
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• 2011

유치의 치수 감염에 대한 적절한 치료가 이루어지지 않거나 치료가 실패한 경우 치근단 병소를 야기할 수 있다. 이는 발육중인 계승 영구치에도 영향을 주어 법랑질 형성 부전, 치배의 위치 및 맹출 경로 변화, 치근 만곡, 치아 매복 등의 합병증을 유발할 수 있다. 계승 영구치의 맹출 방향에 이상을 일으키는 장애 요인으로는 유치의 만기 잔존, 유구치의 불균형적인 치근 흡수, 유치의 치근단 병소 등의 맹출 전 장애 요인과 외상이나 구강 악습관과 같은 맹출 후 장애 요인이 있다. 맹출 경로의 이상을 보이는 계승 영구치의 치료 방법으로는 주기적인 관찰, 외과적 노출, 교정적 견인, 치아 이식, 발치 등이 있으며 치료 방법 선택시 치아의 위치, 상태, 치근 형성 정도 및 만곡 여부, 맹출 방향, 인접 구조물과의 관계 등을 고려하여야 한다. 본 증례들은 유치의 치근단 병소에 의해 비정상적인 맹출 경로를 보이는 소구치를 가진 환자들에서 감염된 유치의 발거와 공간 유지만으로 이환된 소구치의 양호한 자발적 맹출을 보였기에 보고하는 바이다.

• Korean Journal of Acupuncture
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• 제18권1호
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• pp.95-104
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• 2001

The pain was induced on upper and lower incisor of the rat based on the theory of 'connections of upper incisor pain with stomach meridian and lower incisor pain with large intestine meridian'. Such acupoints as ST36 and LI4 were used for alleviation of upper and lower incisor pain. The digastric myogram (dEMG) was utilized for the pain measurement. The upper incisor pain was gradually decreased during ST36 stimulation and significant differences were observed at 20 and 25 minute point during 60 minutes study. The upper incisor pain was gradually decreased during LI4 acupuncture and 20 minute was the only point that showed a significant difference. The alleviation of lower incisor pain was not obvious during the ST36 acupuncture. The lower incisor pain was gradually decreased during LI4 stimulation with significant differences at 15, 20 and 40 minute point. In conclusion, the upper incisor pain was relieved with ST36 and LI4 acupuncture while LI4 was effective on the lower incisor pain alleviation based on the theory of 'connections of upper incisor pain with stomach meridian and lower incisor pain with large intestine meridian'.

• Restorative Dentistry and Endodontics
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• 제22권2호
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• pp.659-669
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• 1997

The goals of root canal instrumentation are complete debridement of pulp tissue, removal of microbes and affected dentin, and proper cleaning and shaping of the root canal space before obturation. Instrumentation with stainless steel files has been shown to produce undesirable results in canals, regardless of the improved technique or modified file type used. Nickel-Titanium(Ni-Ti) alloy has been shown to be exceptionally elastic, having a lower bending moment and lower permanent set after torsion, compared with similar gauge stainless steel. The purpose of this study was to evaluate the change of root canal prepared by Ni-Ti rotary and stainless steel instruments. Thirty-four single rooted teeth of similar shape and canal size were divided into three groups. The teeth were scanned by computed tomography before instrumentation. In group 1, canals were instrumented using a step-back technique with K-file. In group 2, canals were prepared with K-flex file using the same technique as group 1. Group 3 was prepared with nickel-titanium(Ni-Ti) rotary instrument using a manufacture's instruction. Instrumented teeth were again scanned using computed tomography, and reformated images of the uninstrumented canals were compared with images of the instrumented canals. K-flex file and Ni-Ti file caused significantly less canal transportation than K-file in the 8mm root canal section from the apex(p<0.05). K-flex file and Ni-Ti file produced more centered canal preparation than K-file in the 2mm section(p<0.05). Ni-Ti file maintained more precisely the center of the canal than K-flex file in the 10mm section (p<0.05). There was no difference in the removed volume of canals among each groups.

• Restorative Dentistry and Endodontics
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• 제37권1호
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• pp.41-49
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• 2012

Objectives: The internal adaptation of composite restorations with or without resin modified glass ionomer cement (RMGIC) was analyzed non-destructively using Microcomputed tomography (micro-CT). Materials and Methods: Thirty intact human teeth were used. The specimens were divided into 3 groups. In the control group, the cavities were etched with 10% phosphoric acid for 15 sec. Composite resin was filled into the cavity without adhesive. In group 1, light cured glass ionomer cement (GIC, Fuji II LC, GC) was applied as a base. The cavities were then etched, bonded, light cured and filled with composites. In group 2, the cavities were then etched, bonded, light cured and filled with composites without base application. They were immersed in a 25% silver nitrate solution. Micro-CT was performed before and after mechanical loading. One-way ANOVA with Duncan analysis was used to compare the internal adaptation between the groups before or after loading. A paired t-test was used to compare internal adaptation before and after mechanical loading. All statistical inferences were made within the 95% confidence interval. Results: The silver nitrate solution successfully penetrated into the dentinal tubules from the pulp spaces, and infiltrated into the gap between restoration and pulpal floor. Group 2 showed a lower adaptation than the control group and group 1 (p < 0.05). There was no significant difference between the control group and group 1. For all groups, there was a significant difference between before and after mechanical loading (p < 0.05). Conclusions: The internal adaptation before and after loading was better when composites were bonded to tooth using adhesive than composites based with RMGIC.

• 대한소아치과학회지
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• 제28권2호
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• pp.281-286
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• 2001

매복치아의 치료는 단순한 관찰에서 외과적 노출후 교정적 견인까지 매우 다양하며, 매복치의 위치 이상이 심한 경우에는 자가이식을 고려한다. 치아의 자가이식술은 맹출되었거나, 매복치아, 변위맹출된 치아 혹은 기능을 못하는 치아를 동일한 개체의 구강내에서 기존의 발치와나 외과적으로 형성한 수용부에 재위치시키는 술식을 의미한다. 자가이식할 치아는 치근장의 $\frac{1}{2}{\sim}\frac{3}{4}$정도의 치근 발육시기가 치아가 쉽게 발거되고, 합병증이 적게 생기며, 치근의 최종길이가 충분하게 발육한다. 치근 미완성 치아 이식은 무조건 근관치료 하지 않고, 대부분 치수치유를 목표로 하게 된다. 본 증례는 구순열 부위의 과잉치와 함께 상악 우측 중절치의 맹출지연을 주소로 본원에 내원한 환아로, 방사선사진상 상악 우측 중절치와 측절치의 변위매복을 발견하였으며, 치은내 자가이식술을 시행하여 자발적 맹출을 유도, 정상적 치근발육 및 맹출 후 치열의 양호한 배열을 얻을 수 있었다.

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