• 구강회복응용과학지
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• 제28권3호
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• pp.319-326
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• 2012

세라믹은 오랜 기간 동안 치과용 수복재로 사용되어 왔다. 세라믹이 치과학에 도입되면서, 치과용 수복물은 심미성 면에서 눈부신 발전을 하게 되었다. 그러나 최근 세라믹은 수복재료뿐만 아니라 생체재료로서 주목을 받고 있다. 알루미늄 옥사이드와 사파이어등으로 시작된 연구는 지르코니아가 등장함에 따라 새로운 국면을 맞게 되었다. 특히 지르코니아는 색상이나, 기계적 성질, 생체친화성 등 여러 가지 장점 때문에 전통적으로 임플란트 고정체의 주재료이었던 티타늄의 대체 물질로 연구가 진행되고 있다. 지르코니아의 골반응은 매우 우수하지만, 표면 처리가 매우 어렵기 때문에 표면 처리된 티타늄보다는 뛰어나지 못하다는 내용들이 보고되고 있다. 이러한 한계점을 벗어나기 위해, 표면에 화학처리를 하거나 처음부터 다공성 형태를 갖도록 성형하는 방법과 다른 물질로 코팅처리하는 방법들이 소개되었고, 그 결과 수종의 지르코니아 임플란트가 현재 상용화된 상태이다. 앞으로 골이식재 구성성분으로서의 연구 등 다양한 목적의 생체재료로서 지르코니아의 활용에 대한 연구가 이루어질 것으로 사료된다. 이 논문에서는 생체재료로서의 지르코니아에 대한 연구와 앞으로의 발전가능성 등에 관한 문헌을 고찰할 것이다.

• 구강회복응용과학지
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• 제25권3호
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• pp.243-253
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• 2009

임플란트 술식에서 방사선 영상 기술, 컴퓨터 소프트웨어의 발전으로 정확한 진단 및 surgical guide의 제작이 가능해졌다. 본 증례는 양악 무치악 환자에서 고정성 임플란트 보철을 위해 CAD/CAM technique을 이용하여 수술을 하고 즉시 하중을 가한 증례이다. Planning software program을 이용하여 해부학적 구조물과 단면상을 고려하여 상 하악에 각각 6개씩의 임플란트를 최적의 위치에 계획하였다. 정밀한 surgical guide 이용하여 미리 계획된 위치와 방향으로 무절개 임플란트 식립 수술을 시행하였다. 즉시 사용 가능한 고정성 임시 보철물을 미리 제작해 수술 직후 장착하여 환자의 만족도를 높였으며, 이를 6개월간 평가하여 심미적이며, 기능적으로 안정적인 최종 보철물을 제작할 수 있었다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제41권3호
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• pp.156-164
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• 2015

Bilateral sagittal split ramus osteotomy is considered a standard technique in mandibular orthognathic surgeries to reduce unexpected bilateral stress in the temporomandibular joints. Unilateral sagittal split ramus osteotomy (USSO) was recently introduced to correct facial asymmetry caused by asymmetric mandibular prognathism and has shown favorable outcomes. If unilateral surgery could guarantee long-term postoperative stability as well as favorable results, operation time and the incidence of postoperative complications could be reduced compared to those in bilateral surgery. This report highlights three consecutive cases with long-term follow-up in which USSO was used to correct asymmetric mandibular prognathism. Long-term postoperative changes in the condylar contour and ramus and condylar head length were analyzed using routine radiography and computed tomography. In addition, prior USSO studies were reviewed to outline clear criteria for applying this technique. In conclusion, patients showing functional-type asymmetry with predicted unilateral mandibular movement of less than 7 mm can be considered suitable candidates for USSO-based correction of asymmetric mandibular prognathism with or without maxillary arch surgeries.

• 대한치과보철학회지
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• 제52권3호
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• pp.252-257
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• 2014

완전 무치악 환자에서 전악 수복시 환자 고유의 악간관계, 교합평면의 위치, 구순지지, 치아형태와 교합양상을 알 수 없기 때문에 그 모든 것을 임시의치에 기록한 후 이것을 최대한 최종 보철물에 반영하여 이상적인 보철물을 제작해 주어야 한다. 본 증례의 환자는 치주질환에 의한 다수 치아 동요가 존재하여 예후가 불량한 잔존치아 전악 발거 후 임플란트 식립하여 임시치아에 환자의 수직 및 수평 악간관계, 교합평면의 위치, 수직 및 수평 피개의 양, 치아 크기, 전치부 길이를 기록하였다. 그 후 임시치아를 스캐너와 CAD/CAM 기술을 이용하는 double scanning technique로 복제하여 임시치아와 동일한 형태의 단일 구조 지르코니아 브릿지 보철물을 제작하였다. 치료 이후 4개월간의 임상 관찰에서 환자는 심미적, 기능적으로 만족하고 안정적으로 유지되었기에 이를 보고하고자 한다.

• 센서학회지
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• 제18권4호
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• pp.294-300
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• 2009

Cardiopulmonary resuscitation(CPR) is performed by artificial ventilation and thoracic compression for the patient under emergent situation to maintain at least the minimum level of respiration and blood circulation for life survival. Quality of the pre-hospital CPR not only significantly affects the patient's survival rate but also minimizes side effects caused by CPR. Good quality CPR requires monitoring respiration, however, traditional respiratory air flow transducers cannot be used because the transducer elements are located on the flow axis. The present study developed a new technique with no physical object on the flow stream but enabling the air flow measurement and easily incorporated with the CPR devices. A turbulence chamber was formed in the middle of the respiratory tube by locally enlarging the cross-sectional area where the flow related turbulence was generated inducing energy loss which was in turn converted into pressure difference. The turbulence chamber was simply an empty enlarged air space, thus no physical object was placed on the flow stream, but still the flow rate could be evaluated. Both inspiratory and expiratory flows were obtained with symmetric measurement characteristics. Quadratic curve fitting provided excellent calibration formula with a correlation coefficient>0.999 (P<0.0001) and the mean relative error<1 %. The present results can be usefully applied to accurately monitor the air flow rate during CPR.

• Imaging Science in Dentistry
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• 제45권4호
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• pp.205-211
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• 2015

Purpose: This study was performed to compare the accuracy of micro-computed tomography (CT) and cone-beam computed tomography (CBCT) in detecting accessory canals in primary molars. Materials and Methods: Forty-one extracted human primary first and second molars were embedded in wax blocks and scanned using micro-CT and CBCT. After the images were taken, the samples were processed using a clearing technique and examined under a stereomicroscope in order to establish the gold standard for this study. The specimens were classified into three groups: maxillary molars, mandibular molars with three canals, and mandibular molars with four canals. Differences between the gold standard and the observations made using the imaging methods were calculated using Spearman's rho correlation coefficient test. Results: The presence of accessory canals in micro-CT images of maxillary and mandibular root canals showed a statistically significant correlation with the stereomicroscopic images used as a gold standard. No statistically significant correlation was found between the CBCT findings and the stereomicroscopic images. Conclusion: Although micro-CT is not suitable for clinical use, it provides more detailed information about minor anatomical structures. However, CBCT is convenient for clinical use but may not be capable of adequately analyzing the internal anatomy of primary teeth.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제46권4호
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• pp.250-257
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• 2020

Objectives: Palatal infiltration is the most painful and uncomfortable anesthesia technique for maxillary impacted third molar surgery (MITMS). This approach could cause patients distress and aversion to dental treatment. The aim of this study was to evaluate the anesthetic efficacy of a buccal infiltration injection without a palatal injection in MITMS. Materials and Methods: This prospective research study was a crossover split mouth-randomized controlled trial. Twenty-eight healthy symmetrical bilateral MITMS patients (mean age, 23 years) were randomly assigned to two groups. Buccal infiltration injections without palatal injections were designated as the study group and the buccal with palatal infiltration cases were the control group, using 4% articaine and 1:100,000 epinephrine. The operation started after 10 minutes of infiltration. Pain assessment was done using a visual analogue scale and a numeric rating scale after each injection and extraction procedure. Similarly, the success rate, hemodynamic parameters, and additional requested local anesthetic were assessed. Results: The results showed that the pain associated with local anesthetic injections between both groups were significantly different. However, the success rates between the groups were not significantly different. Postoperative pain was not significant between both groups and a few patients requested an additional local anesthetic, but the results were not statistically significant. For hemodynamic parameters, there was a significant difference in systolic pressure during incision, bone removal, and tooth elevation. In comparison, during the incision stage there was a significant difference in diastolic pressure; however, other steps in the intervention were not significantly different between groups. Conclusion: We concluded that buccal infiltration injection without palatal injection can be an alternative technique instead of the conventional injection for MITMS.

• 구강회복응용과학지
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• 제23권4호
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• pp.293-302
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• 2007

I. Objectives The purpose of this study was to compare the shaping ability between the single length technique performed with Mtwo instruments (VDW, Munich, Germany) and the crown-down technique using K3 (SybronEndo, West Collins, CA, USA) and RaCe (FKG, La Chaux-de-Fonds, Switzerland) instruments. II. Materials & Methods Forty five curved canals in resin blocks were equally divided in to three groups. Group 1 (Mtwo) was instrumented used the full length of canal according to the manufacturer's instructions. The simulated canals was prepared to an instrument size of 35, 0.04 taper canal terminus. In group 2 (Race) and group 3 (K3) was instrumented in a crown-down manner and prepared to an instrument size of 30, 0.06 taper canal terminus. Pre- and post-instrumentation images were scanned and assessment of canal shape was completed with a computer image analysis program. Material removal was measured at 7 measuring points, beginning 1mm from the end point of preparation. Differenced of centering ratio were statistically analyzed using One-way ANOVA followed by Duncan's test. II. Results & Conclusion There was no significant difference on 1, 2, 3 and 7mm measuring point. At 4 and 5 measuring point, significant difference showed between the Mtow instruments and other two instruments. (p<0.05)

• Restorative Dentistry and Endodontics
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• 제22권2호
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• pp.648-658
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• 1997

The purpose of this study was to compare the effects of various techniques on the quality and quantity of instrumentation in curved canals. Instrumentation time was evaluated too. Forty eight canals of resin blocks($35^{\circ}$) were divided into three groups and filed. In group A, 16 blocks were instrumented using a step-back technique with stainless steel(SS) K-file(Mani, Matsutani Seisakusho Co.,Japan). In group B, canals were prepared with SS K-files using the Endo-Angle (Nakanishi Dental MFG.CO.,LTD.,Japan). Group C was prepared using N i-Ti engine-driven instruments (Quantec Series $2000^{TM}$ system). Group A and B were filed from # 5 to # 25 at the apex followed by a 1 mm stepback technique, and the coronal half of the canals were flared with Gates Glidden burs(#2,3,4). Group C was instrumented from # 1 to # 8. After the instrumentation time was measured, canals were filled with India ink, and photographed, which to magnify the canal images 8 times. Using these photographs the apical portions were evaluated And scored from 1 to 4 according to the severity of ledging and zipping. On the same photographs, the area of the coronal two thirds of the canals were measured using a personal computer with the computer program Brain and Digitizer (SummaSketch III). The following results were obtained. 1. Instrumentation time was significantly shorter for group C, as opposed to group A and B(ANOVA, P<0.05). 2. The qualitative evaluation of the apical portions of the canals showed no significant difference between the groups(Kruscal-Wallis, p>0.05). 3. The area removed by group C was significantly smaller than group A and B(ANOVA, P<0.05).

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제40권6호
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• pp.272-277
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• 2014

Objectives: Non-vascularized iliac crest bone graft (NVIBG) is a known treatment option in mandibular reconstruction following jaw resection, but no documented review of patients treated with NVIBG exists for northern Nigeria. The experience and technique from a Nigerian tertiary hospital may serve as baseline data for comparison and improvement of practice for other institutions. Materials and Methods: A retrospective review of medical records and patient case files from January 2012 to December 2013 was undertaken. All case files and other medical records of patients who had reconstruction with NVIBG for benign or malignant lesions with immediate or delayed reconstruction were selected for review. Results: Twenty patients had mandibular reconstruction with NVIBG during the study period. Two patients were excluded because of incomplete medical records. Eighteen patients' (male=14, female=4) records were reviewed. Their ages ranged from 13 to 62 years (mean $26.0{\pm}10.6years$). Indications for NVIBG included jaw tumors (n=16; 88.3%), jaw cyst (n=1; 5.6%) and gunshot injury (n=1; 5.6%). Jaw tumors seen were ameloblastoma (n=15; 83.3%) and osteosarcoma (n=1; 5.6%). Treatments done were mandibular resection with condylar resection (n=7; 38.9%), mandibular segmental resection (n=10; 55.6%) and subtotal mandibulectomy (n=1; 5.6%). Patients' postoperative reviews and radiographs revealed good facial profile and continued bone stability up to 1 year following NVIBG. Conclusion: NVIBGs provide an acceptable alternative to vascularized bone grafts, genetically engineered bone, and distraction osteogenesis for mandibular reconstruction in resource-limited centers.