• Restorative Dentistry and Endodontics
• /
• 제41권4호
• /
• pp.278-282
• /
• 2016

Objectives: Glass ionomer cements (GICs), which are biocompatible and adhesive to the tooth surface, are widely used nowadays for tooth restoration. They inhibit the demineralization and promote the remineralization of the tooth structure adjacent to the restoration, as well as interfere with bacterial growth. Hence, the present study was conducted to assess and compare the antimicrobial activity of three commercially available GICs against two cariogenic bacteria. Materials and Methods: An agar plate diffusion test was used for evaluating the antimicrobial effect of three different GICs (Fuji IX, Ketac Molar, and d-tech) on Streptococcus mutans (S. mutans) and Lactobacillus acidophilus (L. acidophilus). Thirty plates were prepared and divided into two groups. The first group was inoculated with S. mutans, and the second group was inoculated with L. acidophilus. These plates were then incubated at $37^{\circ}C$ for 24 hours. Zones of bacterial growth inhibition that formed around each well were recorded in millimeters (mm). Results: The zones of inhibition for Fuji IX, Ketac Molar, and d-tech on S. mutans were found to be $10.84{\pm}0.22mm$, $10.23{\pm}0.15mm$, and $15.65{\pm}0.31mm$, respectively, whereas those for L. acidophilus were found to be $10.43{\pm}0.12mm$, $10.16{\pm}0.11mm$, and $15.57{\pm}0.13mm$, respectively. Conclusions: D-tech cement performed better in terms of the zone of bacterial inhibition against the two test bacteria, than the other two tested glass ionomers.

• Imaging Science in Dentistry
• /
• 제47권3호
• /
• pp.181-187
• /
• 2017

Purpose: The purpose of this study was to measure the buccal bone thickness and angulation of the maxillary incisors and to analyze the correlation between these parameters and the root position in the alveolar bone using cone-beam computed tomography (CBCT). Materials and Methods: CBCT images of 398 maxillary central and lateral incisors from 199 patients were retrospectively reviewed. The root position in the alveolar bone was classified as buccal, middle, or palatal, and the buccal type was further classified into subtypes I, II, and III. In addition, the buccolingual inclination of the tooth and buccal bone thickness were evaluated. Results: A majority of the maxillary incisors were positioned more buccally within the alveolar bone, and only 2 lateral incisors(0.5%) were positioned more palatally. The angulation of buccal subtype III was the greatest and that of the middle type was the lowest. Most of the maxillary incisors exhibited a thin facial bone wall, and the lateral incisors had a significantly thinner buccal bone than the central incisors. The buccal bone of buccal subtypes II and III was significantly thinner than that of buccal subtype I. Conclusion: A majority of the maxillary incisor roots were positioned close to the buccal cortical plate and had a thin buccal bone wall. Significant relationships were observed between the root position in the alveolar bone, the angulation of the tooth in the alveolar bone, and buccal bone thickness. CBCT analyses of the buccal bone and sagittal root position are recommended for the selection of the appropriate treatment approach.

• Journal of Periodontal and Implant Science
• /
• 제49권5호
• /
• pp.299-309
• /
• 2019

Purpose: To analyze the ridge profile of the anterior maxilla using cone-beam computed tomography and to assess the clinical significance of the ridge profile by performing virtual implant placement. Methods: Thirty-two cone-beam computed tomography scans of anterior maxillae were included. For each tooth, a vertical line was made along the longitudinal axis, and 3 horizontal lines at 1-, 3-, and 5-mm levels below the labial bone crest were drawn perpendicularly to the vertical reference. At these levels, the thickness of the alveolar ridge (RT), and the labial (LT) and palatal bone plate (PT) were measured. Then, virtual implant placement using standard and tapered implants was performed. A generalized linear mixed model was used for statistical analysis. Results: The teeth were located labially based on the proportion of LT and PT with respect to RT. At the 1-mm level, the value of LT was between $1.0{\pm}0.4mm$ for central incisors and $1.3{\pm}0.6mm$ for canines. A large number of teeth had area(s) with less than 1-mm-thick labial bone between the 1- and 5-mm levels below the crest. The mean PT was generally thicker than the LT in all tooth types. The greatest mean value of labial concavity was observed for canines, compared to other tooth types. Men had a greater RT than did women, but had a comparable LT. Less apical fenestration was observed when tapered implants were used. Conclusions: Most teeth in the anterior maxilla had a thin labial bone plate, with no significant difference between sexes. Tapered implants may be advantageous for the anterior maxilla.

• 대한치과교정학회지
• /
• 제40권4호
• /
• pp.276-287
• /
• 2010

본 증례보고는 심한 양악 치아치조성 전돌과 전치부 치열밀집을 보이는 23세 8개월 여자 환자를 대상으로 한 변형된 형태의 설측 교정치료법인 설측 Biocreative therapy 치료를 소개하고자 한다. 양악 제1소구치 발치 후 구개천장에 식립된 C-플래이트에 lingual sheath가 달린 보조장치를 접착하여 상악구치부에 장치부착 없이 튜브역할을 대신하게 하였으며 상악 전치부의 decrowding과 견인을 위하여 설측 교정용 브라켓을 사용하지 않고 0.022 슬롯을 가진 순측 브라켓을 치아 설면에 부착한 후 납착된 설측 레버암을 이용하여 상악 전치부의 3차원적인 견인을 시행하였으며, 견인 후 finishing 기간동안 tooth positioner를 사용하였다. 상악 구치부의 장치부착 없이도 총 치료기간은 19개월 소요되었고, 안정적인 교합관계와 안모의 개선이 이루어졌다. 장치 제거 후 13개월 유지 후에도 양호한 결과가 유지되었다.

• 한국정밀공학회지
• /
• 제26권5호
• /
• pp.104-111
• /
• 2009

A ship engine operator should compensate the crankshaft assembly of ship engine after inspecting crankshaft deflection error in the crank throw regularly to avoid engine vibration and abrasions. In the previous method, the operator enters the bed plate and measures crankshaft deflection using dial gauge on rotating crankshaft manually. However, this method can cause dangerous situation to the operator as well as uncomfortable in an inferior environment. In order to solve the problems, this paper studies the method which makes the operator measure the error outside of the bed plate. In this paper, it is suggested that BlueTooth wireless communication transfers the error data to the outer standing operator with digitalized crankshaft deflection inspection device developed in this paper. So, the wireless measurement system is developed and applied to a medium-speed marine engine through size-miniaturization. After applying test, the developed inspection device showed that it provides much safe and ease inspection method. Furthermore, in the result, the measuring accuracy is more improved.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제42권4호
• /
• pp.182-186
• /
• 2016

Objectives: The purpose of this study was to analyze the incidence of indications for the removal of mini-plates over a five-year period in maxillofacial trauma patients. Materials and Methods: The medical records of 530 patients who underwent treatment with mini-plate fixation after maxillofacial trauma were reviewed for a five-year period (May 2007 to May 2012). Patients were evaluated concerning the number of mini-plates removed, age and gender distributions, time between insertion and removal, indication for removal, and site of removal. Results: The plates of 120 patients were removed (26 females and 94 males). The removal rate was 22.6%. The most frequent indication for removal was patient demand (81.7%), followed by tooth extraction (7.5%), and pain (3.3%). The most frequent removal site was the mandible (95.0%). Conclusion: The number of mini-plates removed was small, and the most common indication for removal was patient demand. There is no evidence to support a recommendation for the routine removal of titanium mini-plates.

• 대한치과의사협회지
• /
• 제53권5호
• /
• pp.348-359
• /
• 2015

Objective: The aim of this study was to determine the effect of multi-layer of a collagen membrane alone or loaded rhBMP-2 on the buccal plate for ridge preservation after tooth extraction. Material and methods: Following bilateral extraction of the maxillary 1st and 3rd premolars in five dogs, rhBMP-2 loaded collagen membrane was applied to the buccal plates at the 1st premolar and collagen membrane only was applied to the buccal plates at the 3rd premolar unilaterally. The collagen membranes applied in the experimental groups were piled into four layers. The corresponding sites of the contralateral side healed naturally. After 3months of healing, the animals were sacrificed. Radiographic and histologic analyses were performed. Results: There was no significant difference in the healing of extraction socket at both 1st and 3rd premolars. In microcomputed tomography, the widths of the residual ridge of the experimental groups were similar with the controls. Histologically, the experimental groups did not exhibit different pattern compared to the controls regardless of the addition of rhBMP-2. Conclusion: Layering of the collagen membrane with or without rhBMP-2 on the buccal plate failed to show the effectiveness in dimensional preservation of the extraction socket.

• 대한치과교정학회지
• /
• 제48권2호
• /
• pp.81-89
• /
• 2018

Objective: The aim of this study was to evaluate the stress distribution and displacement of various craniofacial structures after nonsurgical rapid palatal expansion (RPE) with conventional (C-RPE), bone-borne (B-RPE), and miniscrew-assisted (MARPE) expanders for young adults using three-dimensional finite element analysis (3D FEA). Methods: Conventional, bone-borne, and miniscrew-assisted palatal expanders were designed to simulate expansion in a 3D FE model created from a 20-year-old human dry skull. Stress distribution and the displacement pattern for each circumaxillary suture and anchor tooth were calculated. Results: The results showed that C-RPE induced the greatest stress along the frontal process of the maxilla and around the anchor teeth, followed by the suture area, whereas B-RPE generated the greatest stress around the miniscrew, although the area was limited within the suture. Compared with the other appliances, MARPE caused relatively even stress distribution, decreased the stress on the buccal plate of the anchor teeth, and reduced tipping of the anchor teeth. Conclusions: The findings of this study suggest that the incorporation of miniscrews in RPE devices may contribute to force delivery to the sutures and a decrease in excessive stress on the buccal plate. Thus, MARPE may serve as an effective modality for the nonsurgical treatment of transverse maxillary deficiency in young adults.

• Imaging Science in Dentistry
• /
• 제51권3호
• /
• pp.251-260
• /
• 2021

Purpose: Dental implants are widely used for the rehabilitation of edentulous sites. This study investigated the occurrence of dental implant malpositioning as shown on post-implantation cone-beam computed tomography (CBCT) and to identify related factors. Materials and Methods: Samples with at least 1 malpositioned dental implant were collected from a central radiology clinic in Tehran, Iran from January 2017 to January 2019. Variables such as demographic characteristics, length and diameter of implants, type of implant, sites of implant insertion, different types of implant malpositioning problems (cortical plate perforation, interference with anatomical structures), angulation of the implant, and the severity of malpositioning were assessed. In addition, the incidence of implant fracture and over-drilling was evaluated. Data were statistically analyzed using the chi-square test, 1-sample t-test, and Spearman correlation coefficients. Results: In total, 252 patients referred for implant postoperative CBCT evaluations were assessed. The cases of implant malpositioning included perforation of the buccal cortical plate (19.4%), perforation of the lingual cortical plate (14.3%), implant proximity to an adjacent implant (19.0%), implant proximity to an adjacent tooth (3.2%), interference with anatomical structures(maxillary sinus: 18.3%, mandibular canal: 11.1%, nasal cavity: 6.3%, mental foramen: 5.6%, and incisive canal: 0.4%). Implant fracture and over-drilling were found in 1.6% and 0.8% of cases, respectively. Severity was categorized as mild (9.5%), moderate (35.7%), severe (37.7%), and extreme (17.1%), and 52.4% of implants had inappropriate angulation. Conclusion: CBCT imaging is recommended for detecting dental implant malpositioning. The most common and severe type of malpositioning was buccal cortex perforation.

• 대한치과교정학회지
• /
• 제35권1호
• /
• pp.51-59
• /
• 2005

본 연구는 교정환자의 브라켓과 치아 경계부 및 브라켓으로부터 2mm 이상 떨어진 치아 평활면의 치면세균막에 존재하는 mutans streptococci의 종 및 생물형에 차이가 있는지를 알아보고자 시행되었다. 조선대학교 치과병원에 내원한 13세 이상 35세 미만의 환자 28명으로부터 브라켓을 장착하고 있는 61개 치아에서 치균세균막을 채취하여 mutans streptococci를 MSB 배지에서 선택적으로 분리한 다음, 이들의 지놈 DNA를 추출하여 dextranase 유전자를 표적으로 하는 중합효소연쇄반응법을 시행하고, 그 증폭물을 Hae III로 소화하고, 이를 전기영동하여 제한 효소절편길이에 따라 그 종을 식별하였다. 또한 생물형을 조사하기 위하여 생화학적 검사를 실시하였다. 그 결과 브라켓과 치아 경계부 및 브라켓으로부터 2mm 이상 떨어진 평활면의 치면세균막에 존재하는 mutans streptococci 종은 서로 비슷한 검출 빈도를 보이나, 두 곳에 존재하는 mutans streptococci 생물형은 서로 차이가 있는 것으로 나타났다 향후 브라켓과 치아 경계부 및 치아 평활면의 치면세균막의 mutans Streptococci 생물형의 차이와 브라켓 주위의 법랑질 탈회 및 치아우식증 발병과의 상관관계에 대한 연구가 필요하다.