• 대한치과보철학회지
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• 제55권3호
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• pp.258-263
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• 2017

목적: 이번 연구에서, 다양한 상황에서 골소실양을 평가하기 위하여 맞춤형 지대주를 사용한 환자에서 4년간의 후향적 방사선학적인 연구를 시행하였다. 대상 및 방법: 이번 연구의 대상은 CAD/CAM 맞춤형 지대주를 이용한 임플란트 고정성 보철물이다. 2011년 8월 1일부터 2012년 7월 31일 까지 조선대학교 치과병원 보철과에서 제작하여 고정성 보철물로 사용된 CAD/CAM 맞춤형 지대주와 상부 보철물들을 대상으로 하였으며, 고정성 보철물을 제작한 환자에 대하여 방사선학적 평가를 시행하여 보철물 장착 후 3개월, 6개월, 1년, 2년, 3년, 4년 단위로 총 4년 간의 후향적 연구를 시행하였다. 결과:연구 결과, CAD/CAM을 이용한 맞춤형 지대주는 기존 연구 결과에 비해 골소실 양이 적었다. 연결 고정된 그룹과 연결 고정되지 않은 그룹 간에 골소실 양(각각 0.27 mm, 0.5 mm)에 통계적으로 유의한 차이가 없었다. 또한 상악 전치부, 상악 구치부, 하악 전치부, 하악 구치부의 부위별 골소실양(각각 1.37 mm, 0.39 mm, 0.00 mm, 0.30 mm)에 통계적으로 유의한 차이가 있었다. 결론:CAD/CAM을 이용한 맞춤형 지대주는 연결 고정 여부에 따른 골소실 양에서 통계적으로 유의한 차이가 없었으며, 임플란트 식립 부위에 따른 골소실 양에서 통계적으로 유의한 차이가 있었다.

• Journal of Periodontal and Implant Science
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• 제41권5호
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• pp.211-217
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• 2011

Purpose: The marginal bone levels around implants following restoration are used as a reference for evaluating implant success and survival. Two design concepts that can reduce crestal bone resorption are the microthread and platform-switching concepts. The aims of this study were to analyze the placement of microthreaded and platform-switched implants and their short-term survival rate, as well as the level of bone around the implants. Methods: The subjects of this study were 27 patients (79 implants) undergoing treatment with microthreaded and platform-switched implants between October 2008 and July 2009 in the Dental Hospital of Yonsei University Department of Periodon-tology. The patients received follow-up care more than 6 months after the final setting of the prosthesis, at which time periapical radiographs were taken. The marginal bone level was measured from the reference point to the lowest observed point of contact between the marginal bone and the fixture. Comparisons were made between radiographs taken at the time of fixture installation and those taken at the follow-up visit. Results: During the study period (average of 11.8 months after fixture installation and 7.4 months after the prosthesis delivery), the short-term survival rate of microthreaded and platform-switched implants was 100% and the marginal bone loss around implants was $0.16{\pm}0.08$ mm, the latter of which is lower than the previously reported values. Conclusions: This short-term clinical study has demonstrated the successful survival rates of a microthread and platform-switched implant system, and that this system is associated with reduced marginal bone loss.

• 대한치과교정학회지
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• 제53권4호
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• pp.264-275
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• 2023

Objective: To investigate the effects of maxillary orthodontic expansion on the alveolar bone tissue in adult patients treated with aligners by using cone-beam computed tomography. Methods: Thirty patients (22 females and 8 males; mean age: 36.3 years) were treated with Invisalign^® aligners. Cone-beam computed tomography and digital models were obtained before (T0) and after (T1) upper arch expansion. The bone thicknesses in the cervical, middle, and apical areas of the incisors, canines, premolar, and first molars were buccally and palatally measured, totaling 96 areas and 2,880 measurements. The buccolingual inclinations and transverse measurements of the teeth were obtained from digital models to correlate them with the bone changes. The statistical tests used were Student's t-test, analysis of variance, and Pearson's correlation tests (p < 0.05). Results: From the 96 areas evaluated, 84 revealed an increase or stability in the alveolar bone thickness and twelve displayed significant bone loss. Bone changes did not correlate with the tooth inclination and transverse measurements. Conclusions: Within the limitation of the present study, mild levels of upper arch expansion obtained with Invisalign^® aligners in adult patients did not result in any clinically significant loss of alveolar bone thickness.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제33권2호
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• pp.149-153
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• 2011

Purpose: The aim of the present study was to evaluate the clinical outcome of resorbable blasting media surface tapered implant. Methods: 169 Osstem$^{(R)}$ GS III dental implants in 73 patients who received implant treatments at Seoul National University Bundang Hospital, were included in this study. The incidence of biological and prosthetical complications has been carefully analysed for each implant. Results: The short-term implant survival rate was 97.63%, success rate 94.7%. The prevalence of biological complications was 15.38% and the prevalence of prosthetic complications was 13.04%. The mean value of crestal bone loss was $0.28{\pm}0.57$ mm. The relationship between loading periods and marginal bone loss was small and not statistically significant. In mandible, marginal bone loss was larger than in maxilla, no statistically significant. Also, length and diameter of implant had no relationship with marginal bone loss. Conclusion: We suggest that this implant system could achieve successful and stable results.

• The Journal of Advanced Prosthodontics
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• 제10권2호
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• pp.163-166
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• 2018

PURPOSE. The marginal bone loss of implants with laser treated surface was investigated after six weeks of loading after implant installation to the mandible molar area. MATERIALS AND METHODS. A total of 23 implants were placed in the edentulous molar area of the mandible: 13 implants were immediately loaded and 10 implants were early loaded. The implants used were made of titanium grade 23, screw shaped, 4.2 mm in diameter, and 10 mm in length. Patients were evaluated with resonance frequency analysis at implant fixture installation and 1, 2 (final prosthesis installation), 3, 5, 8, and 14 months later. X-rays were taken at 2 months after fixture installation and 1, 2, 3 years after to measure the marginal bone loss. RESULTS. The mean ISQ value measured at the implant installation was over 70 at all-time points. The average of marginal bone loss was average 0.33 mm. CONCLUSION. Immediate implant loading for laser treated implants would be possible.

• 치과방사선
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• 제25권1호
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• pp.99-107
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• 1995

The aim of this study was to evaluate clinician's detectability in the diagnosis of bone loss in the bifurcation of mandibular molars on periapical radiographs and Digital images. Periapical radiographs were obtained of the first molars in 2 dry mandibles after preparation of bony defects corresponding to degree I, degree II and degree III buccal furcation involvements. The radiographs were randomly presented to 39 clinicians(1 oral radiologist, 4 periodontist, 34 general dentists) who were asked to determine the presence or absence of bone loss. Periapical films were digitized with a TV camera. Digital images were assessed by 15 clinicians(1 oral radiologist, 4 periodontist, 10 general dentists). I. the overall diagnostic accuracy of Digital images for detection of bone loss in the bifurcation of mandibular molars was higher than that of the periapical radiographs. 2. the largest increase in diagnostic accuracy was found between lesion grade II and III on both radiographs and Digital images(P<0.05). 3. there was no significant difference between the standard state and the controlled contrast state on Digital images. 4. the overall diagnostic accuracy of I radiologist and 4 periodontists was better than that of the general dentists for detecting bifurcation involvements.

• 한국정밀공학회지
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• 제31권8호
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• pp.749-755
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• 2014

The aim of this study was to assess the effects of artificial unloading induced by hindlimb suspension on the trabecular bone in tibiae. Twenty four 12-week-old Sprague-Dawley rats were assigned to 3 groups, namely, the control group (CON, n = 8), the hindlimb-suspended group (HLS, n = 8) and HLS with partial vibration group (HLSPV, n = 8). After 4 weeks, compared with CON group, HLS group had significantly greater decreases on BMD, BV/TV, Tb.N, Conn.Dn and increase on Tb.Sp (p < 0.05). However, there were no significant differences in BMD and the other micro structural parameters of tibial trabecular bones between CON and HLSPV (p > 0.05). These results implied that partial vibration might inhibit the bone loss induced by hindlimb suspension. Furthermore, we could expect to apply partial vibration system in space environment, to prevent bone loss in astronauts.

• 대한의용생체공학회:의공학회지
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• 제33권4호
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• pp.207-212
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• 2012

It is widely known that sciatic nerve injury (SNI) can negatively affect the biomechanical characteristics of the musculoskeletal system. However, there were no studies that evaluated and compared denervated side with another side limb at the same time. In this study, sixteen male 12-week-old mice were allocated into two groups: HEMI (Right Sciatic nerve denervated) and CON (Control). Both limbs were scanned using micro-CT at 0 week and 4 weeks. There were significant differences in relative variation (RV) of BMD and all structural parameters compared CON and HEMI in right tibia (p < 0.05). Tb.Th and Tb.Sp distributions were differed CON with HEMI in right tibia. In left tibia, there were significant differences in RV of BMD (p < 0.05) and Tb.Sp distribution. These result means that SNI can induce bone loss in the both side tibiae. However, there was a different profile of bone loss between left and right tibiae.

• International Journal of Oral Biology
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• 제41권1호
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• pp.33-38
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• 2016

One of functions of Galla Rhois (GR) is reportedly an anti-inflammatory effect on the several inflammatory diseases. However, an effect of GR related to periodontitis has not been investigated. In the present study, we examined the effect of the hexane extract of Galla Rhois (GR-H) on periodontitis. Cytotoxicity was assessed by MTS analysis using human gingival fibroblast (hGF) cells. Experimental periodontitis was induced by injecting E.coli LPS into the palatal gingiva maxillary molar thrice weekly for 3 weeks (LPS group). GR-H diluted in 1xPBS was orally administrated using a syringe at 30 mg/kg body weight and 100 mg/kg body weight once a day (GR-H group). GR-H effect on the alveolar bone loss (ABL) was digitized with a micro-CT. GR-H treatment at concentrations exceeding 0.5 mg/ml showed cytotoxic effect in hGF cells. The micro-CT among groups were presented for the different distances from cemento-enamel junction (CEJ) to alveolar bone crest (ABC). The results indicated an inhibitory effect on alveolar bone loss for orally administered GR-H in a model of LPS-induced periodontitis.

• Restorative Dentistry and Endodontics
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• 제38권2호
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• pp.59-64
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• 2013

Apical surgery cuts off the apical root and the crown-to-root ratio becomes unfavorable. Crown-to-root ratio has been applied to periodontally compromised teeth. Apical root resection is a different matter from periodontal bone loss. The purpose of this paper is to review the validity of crown-to-root ratio in the apically resected teeth. Most roots have conical shape and the root surface area of coronal part is wider than apical part of the same length. Therefore loss of alveolar bone support from apical resection is much less than its linear length.The maximum stress from mastication concentrates on the cervical area and the minimum stress was found on the apical 1/3 area. Therefore apical root resection is not so harmful as periodontal bone loss. Osteotomy for apical resection reduces longitudinal width of the buccal bone and increases the risk of endo-perio communication which leads to failure. Endodontic microsurgery is able to realize 0 degree or shallow bevel and precise length of root resection, and minimize the longitudinal width of osteotomy. The crown-to-root ratio is not valid in evaluating the prosthodontic prognosis of the apically resected teeth. Accurate execution of endodontic microsurgery to preserve the buccal bone is essential to avoid endo-perio communication.