• Journal of Oral Medicine and Pain
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• 제39권1호
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• pp.2-9
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• 2014

Purpose: The purpose of this study was to compare the clinical and radiographic features of temporomandibular joint (TMJ) osteoarthritis (OA) between adolescents and middle-old aged patients. Methods: The subjects were chosen among the patients who presented to the Department of Oral Medicine of Pusan National University Hospital and were diagnosed with TMJ OA by clinical exam, X-ray and cone-beam computed tomography (CBCT) from 2010 to 2011. We investigated 93 adolescent patients (12-19 years) and 53 middle-old aged (>45 years) patients who observed the erosive bony changes in TMJ. CBCT scans were retaken at intervals at an average of 8 months. Results: The adolescent patients showed unilateral degenerative changes more often, and the middle-old aged patients showed degenerative changes more frequently on both sides. The transition of bone changes to the improved group occurred most commonly in both the adolescent and middle-old aged patients. The adolescent patients were more likely to improve than middle-old aged patients. In the adolescent patients, loss of erosion and subjective symptoms occurred in shorter periods than in the middle-old aged patients. In the adolescent patients, the transition of erosion was distributed into proliferative, normal, and shortening in order. In the middle-old aged patients, the transition of erosion was distributed into shortening, proliferative, and normal in order. Conclusions: The clinical and radiographic features of TMJ OA are a significantly different between the adolescent and middle-old aged patients. Moreover, the difference by age of the adaptive and regenerative capacity of TMJ affects the prognosis of TMJ OA and adolescent patients have a better prognosis after treatment.

• The Journal of Advanced Prosthodontics
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• 제2권3호
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• pp.102-105
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• 2010

PURPOSE. The aims of this study were to suggest a method of fabrication of the record base using a light-polymerized resin by applying the two-phase fabrication method for the improvement of the fit of the record base and to compare the degree of fit according to the separation site. MATERIALS AND METHODS. In the edentulous cast of maxilla, four test groups were considered. In the first, second, third, and fourth test groups (n = 12 in each group) the separation was done at 0, 5, 10, and 15 mm, respectively below the alveolar crest along the palatal plane. For the control group, the record base was made without separating the two sections. The light-body silicone material was injected into the fitting surface of the record base. It was then placed onto the cast and finger pressure was applied to stabilize it in a seated position followed by immediate placement onto the universal test device. Finally, the mass of the impression material was measured after it was removed. ANOVA was performed using the SAS program. For the post-hoc test, the Wilcoxon Rank-Sum test and the Tukey-Kramer HSD test were performed ($\alpha$ = 0.05). RESULTS. The control group and Group 3, 4 showed significant differences. The Group 3 and 4 showed significantly smaller inside gaps than the control group which was not made with the two-phase fabrication method. CONCLUSION. The two-stage polymerized technique can improve the fit of the denture base particularly when the separation was made at 10 to 15 mm from the alveolar crest.

• 대한치과보철학회지
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• 제46권3호
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• pp.280-289
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• 2008

STATEMENT OF THE PROBLEM: Recent data regarding the effects the cement type and abutment heights on the retentive force of a prosthetic crown are inconsistent and unable to suggest clinical guidelines. PURPOSE OF THE STUDY: This study evaluated the effects of different types of temporary cements and abutment heights on the retentive strength of cement-retained implant-supported prostheses. MATERIALS AND METHODS: Prefabricated implant abutments, 4 mm in diameter, $8^{\circ}$taper per side, and light chamfer margins, were used. The abutment heights of the implants were 4 mm, 5.5 mm and 7 mm. Seven specimens of a single crown similar to a first premolar were fabricated. Six commercially available temporary cements, TempBond, TempBond NE, Cavitec, Procem, Dycal, and IRM, were used in this study. Twenty-four hours after cementation, the retentive strengths were measured using a universal testing machine with a crosshead speed of 0.5 mm/min. The cementation procedures were repeated 3 times. The data was analyzed using two-way analysis of variance and a Tukey test (${\alpha}$=0.05). RESULTS: The tensile bond strength ranged from 1.76 kg to 19.98 kg. The lowest tensile strengths were similar in the TempBond and Cavitec agents. Dycal showed the highest tensile bond strength (P<0.01). More force was required to remove the crowns cemented to the long abutments (P<0.05). CONCLUSION: TempBond and Cavitec agents showed the lowest mean tensile bond strength. The Dycal agent showed more than double the tensile bond strength of the TempBond agent.

• 대한치과의사협회지
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• 제56권9호
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• pp.462-478
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• 2018

임플란트와 지대주 간에 허용가능한 적합도를 넘는 부적합을 발견하고 이에 대처하는 것은 중요한 과제이다. 부적합을 임상에서 평가하고 발견하는 방법은 대부분 부적합의 정성적 평가에 치중하고 있으며 술자의 숙련도에 의존하고 있어 정확한 평가방법이라고 하기는 어렵다. 부적합의 정도를 판단하고 원인을 실험적으로 분석하는 방법 중 본 문헌고찰에서는 광탄성 분석법, 유한요소분석법, 스트레인게이지, 미생물 균체 분석 등 조건을 모형화하여 분석하는 모형화법과 사진 측량, 삼차원 좌표 측정, 현미경분석 및 방사선분석을 통해 부적합의 정도를 정밀하게 측정하는 수치법을 각각 설명하고 그 장단점 및 적용의 한계를 분석하였다. 지금까지 살펴본 실험실 부적합 평가 방법들을 장, 단점 및 정확도와 재현성을 기준으로 표로 정리한 것이 Table 3이다. 어떤 방법도 모든 경우에 적용할 수 있을 정도로 완벽하지는 않으므로 평가하고자 하는 부적합의 특성에 따라 적절한 평가방법을 선택하여 적용하는 것이 필요하다고 사료된다.

• 대한심미치과학회지
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• 제13권1호
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• pp.19-24
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• 2004

This study is intended to provide a referable information of exposed amount of maxillary central incisor of Korean by ages and gender under rest position. The result of this study will give guidelines for making prothesis. The subjects of this study are patients of Charmgoun Dental Hospital in Busan, Korea. A statistical analysis was conducted after taking digital photos of patients' teeth with a ruler and measuring the length of teeth on the computer program. The results of this study were as follows : 1. The length of maxillary central incisor that exposed under upper lip is decreased by increasing age in rest position.; the average length is 3.455mm in 20s, 2.525mm in 30s, and 1.543mm in 40s. 2. The exposal length in females is more than males, average length is 2.796mm in female and 2.342mm in male. However, there is not significant difference between the genders. 3. The exposed average length of maxiallry central incisor under upper lip is 2.618mm at rest. 4. The clinical crown average length of maxillary central incisor is 10.195mm, but incresing age, there is no significant defference. 5. There is significant difference between the genders in the clinical crown length of maxillary central incisor.; the length is 10.637mm in men, 9.90mm in women.

• Journal of Periodontal and Implant Science
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• 제42권6호
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• pp.196-203
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• 2012

Purpose: The aim of this study was to evaluate the clinical efficiency of the subepithelial connective tissue graft (SCTG) with and without plasma rich in growth factor (PRGF) in the treatment of gingival recessions. Methods: Twenty bilateral buccal gingival Miller's Class I and II recessions were selected. Ten of the recessions were treated with SCTG and PRGF (test group). The rest ten of the recessions were treated with SCTG (control group). The clinical parameters including recession depth (RD), percentage of root coverage (RC), mucogingival junction (MGJ) position, clinical attachment level (CAL), and probing depth (PD) were measured at the baseline, and 1 and 3 months later. The data were analyzed using the Wilcoxon signed rank and Mann-Whitney U tests. Results: After 3 months, both groups showed a significant improvement in all of the mentioned criteria except PD. Although the amount of improvement was better in the SCTG+PRGF group than the SCTG only group, this difference was not statistically significant. The mean RC was $70.85{\pm}12.57$ in the test group and $75.83{\pm}24.68$ in the control group. Conclusions: Both SCTG+PRGF and SCTG only result in favorable clinical outcomes, but the added benefit of PRGF is not evident.

• Journal of Periodontal and Implant Science
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• 제50권4호
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• pp.251-259
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• 2020

Purpose: This randomized controlled study aimed to evaluate the effects of an electric toothbrush with 3 colors of light-emitting diodes (LEDs) on antiplaque and bleeding control. Methods: This randomized, placebo-controlled, double-blinded, parallel-group clinical trial included 50 healthy adults with gingivitis, who were randomly assigned to 2 groups. The experimental group used electric toothbrushes with 3 colors of LEDs and the control group used the same electric toothbrush as the experimental group, but with LED sources with one-hundredth of the strength. The subjects used the electric toothbrush 3 times a day for 4 minutes each time. As clinical indices, bleeding on marginal probing (BOMP), the Löe-Silness gingival index (GI), and the Turesky-Quigley-Hein plaque index (QHI) were assessed at baseline, at 3 weeks, and at 6 weeks. Results: There were significant decreases in all clinical indices (BOMP, GI, QHI) in both the experimental and control groups compared to baseline at 3 weeks and at 6 weeks. In a comparison between the experimental and control groups, no statistically significant differences were observed for any clinical indices at 3 weeks (P>0.05). However, at 6 weeks, statistically significant differences were observed between the experimental and control groups in BOMP and GI, which are indicators of gingival inflammation (P<0.05). Conclusions: This study demonstrated that an electric toothbrush combined with 3-color LEDs reduced gingival bleeding and inflammation after 6 weeks.

• The Journal of Advanced Prosthodontics
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• 제1권1호
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• pp.37-40
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• 2009

STATEMENT OF PROBLEM. Implant drivers are getting popular in clinical dentistry. Unlike to implant systems with external hex connection, implant drivers directly engage the implant/abutment interface. The deformation of the implant/abutment interface can be introduced while placing an implant with its implant driver in clinical situations. PURPOSE. This study evaluated the change of rotational freedom between an implant and its abutment after application of different insertion torques. MATERIAL AND METHODS. Three kinds of internal connection implants were utilized for the current study($4.5{\times}12\;mm$ Xive, $4.3{\times}11.5\;mm$ Inplant Magicgrip, $4.3{\times}12\;mm$ Implantium MF). An EstheticBase, a 2-piece top, a Dual abutment was used for its corresponding implant system. The rotational freedom between an implant and its abutment were measured before and after applying 45, 100 Ncm insertion torque. Repeated measures ANOVA was used for statistical analysis. RESULTS. Under 45 Ncm insertion torque, the rotational freedom between an implant and its abutment was significantly increased in Xive(P = .003). However, no significant change was noted in Inplant Magicgrip and Implantium MF. Under 100 Ncm torque, both in Xive(P = .0005) and Implatium MF(P = .03) resulted in significantly increased rotational freedom between the implant and its abutment. DISCUSSION. The design of the implant/implant driver interface effectively prevented the deformation of implant/abutment interface. Little change was noted in the rotational freedom between an implant and its abutment, even though the insertion torque was far beyond clinical application. CONCLUSIONS. The implant/abutment joint of internally connecting implants were quite stable under insertion torque in clinical situation.

• The Journal of Advanced Prosthodontics
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• 제11권5호
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• pp.280-285
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• 2019

PURPOSE. The present study was designed to examine the clinical fit of fixed dental prosthesis fabricated by the milling-sintering method using a presintered cobalt-chromium alloy. MATERIALS AND METHODS. Two single metal-ceramic crowns were fabricated via milling-sintering method and casting method in each of the twelve consecutive patients who required an implant-supported fixed prosthesis. In the milling-sintering method, the prosthetic coping was designed in computer software, and the design was converted to a non-precious alloy coping using milling and post-sintering process. In the casting method, the conventional manual fabrication process was applied. The absolute marginal discrepancy of the prostheses was evaluated intraorally using the triple-scan technique. Statistical analysis was conducted using Mann-Whitney U test (${\alpha}=.05$). RESULTS. Eight patients (66.7%) showed a lower marginal discrepancy of the prostheses made using the milling-sintering method than that of the prosthesis made by the casting method. Statistically, the misfit of the prosthesis fabricated using the milling-sintering method was not significantly different from that fabricated using the casting method (P=.782). There was no tendency between the amount of marginal discrepancy and the measurement point. CONCLUSION. The overall marginal fit of prosthesis fabricated by milling-sintering using a presintered alloy was comparable to that of the prosthesis fabricated by the conventional casting method in clinical use.

• Journal of Periodontal and Implant Science
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• 제51권1호
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• pp.63-74
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• 2021

Purpose: This study investigated the effects of hyaluronic acid (HA) on peri-implant clinical variables and crevicular concentrations of the proinflammatory biomarkers interleukin (IL)-1β and tumor necrosis factor (TNF)-α in patients with peri-implantitis. Methods: A randomized controlled trial was conducted in peri-implantitis patients. Patients were randomized to receive a 0.8% HA gel (test group), an excipient-based gel (control group 1), or no gel (control group 2). Clinical periodontal variables and marginal bone loss after 0, 45, and 90 days of treatment were assessed. IL-1β and TNF-α levels in crevicular fluid were measured by enzyme-linked immunosorbent assays at baseline and after 45 days of treatment. Clustering analysis was performed, considering the possibility of multiple implants in a single patient. Results: Sixty-one patients with 100 dental implants were assigned to the test group, control group 1, or control group 2. Probing pocket depth (PPD) was significantly lower in the test group than in both control groups at 45 days (control 1: 95% CI, -1.66, -0.40 mm; control 2: 95% CI, -1.07, -0.01 mm) and 90 days (control 1: 95% CI, -1.72, -0.54 mm; control 2: 95% CI, -1.13, -0.15 mm). There was a trend towards less bleeding on probing in the test group than in control group 2 at 90 days (P=0.07). Implants with a PPD ≥5 mm showed higher levels of IL-1β in the control group 2 at 45 days than in the test group (P=0.04). Conclusions: This study demonstrates for the first time that the topical application of a HA gel in the peri-implant pocket and around implants with peri-implantitis may reduce inflammation and crevicular fluid IL-1β levels.