• The Journal of Advanced Prosthodontics
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• 제6권2호
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• pp.146-149
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• 2014

The major drawback of cement-retained restorations is the extrusion of the excess cement into the peri-implant sulcus, with subsequent complications. Insufficient removal of the excess cement may initiate a local inflammatory process, which may lead to implant failure. This article presents a method of controlling cement flow on implant abutments, minimizing the excess cement around implant-retained restorations.

• 대한치과보철학회지
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• 제55권1호
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• pp.71-78
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• 2017

임플란트 보철물을 지대주 및 임플란트에 연결하는 방법은 크게 나사 유지방식과 시멘트 유지방식으로 나눌 수 있다. 나사 유지형의 장점은 탈착 가능성과 잔류 시멘트가 남지 않는다는 점이나 상대적으로 나사 풀림이나 파절의 비율이 시멘트 유지방식에 비해 높다는 단점이 있다. 반면 시멘트 유지형은 심미적이고 상대적으로 적은 비용으로 보철물을 제작할 수 있으나 탈착의 용이성이 불리하다는 단점이 있다. 이 두 가지의 장점을 조합한 방식으로 SCRP방식이 소개되었다. 그러나 역시 이상적인 임플란트 식립 위치를 전제로 한다. 이러한 여러 가지 보철 방식의 단점들을 해결하기 위하여 잔여 시멘트를 남기지 않으면서 연조직 염증을 예방할 수 있는 fiber post 유지형 보철 연결방식을 새롭게 소개하고자 한다.

• The Journal of Advanced Prosthodontics
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• 제5권3호
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• pp.312-318
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• 2013

PURPOSE. The aim of this study was to compare the passivity of implant superstructures by assessing the strain development around the internal tapered connection implants with strain gauges. MATERIALS AND METHODS. A polyurethane resin block in which two implants were embedded served as a measurement model. Two groups of implant restorations utilized cement-retained design and internal surface of the first group was adjusted until premature contact between the restoration and the abutment completely disappeared. In the second group, only nodules detectable to the naked eye were removed. The third group employed screw-retained design and specimens were generated by computer-aided design/computer-aided manufacturing system (n=10). Four strain gauges were fixed on the measurement model mesially and distally to the implants. The strains developed in each strain gauge were recorded during fixation of specimens. To compare the difference among groups, repeated measures 2-factor analysis was performed at a level of significance of ${\alpha}$=.05. RESULTS. The absolute strain values were measured to analyze the magnitude of strain. The mean absolute strain value ranged from 29.53 to 412.94 ${\mu}m/m$ at the different strain gauge locations. According to the result of overall comparison, the cement-retained prosthesis groups exhibited significant difference. No significant difference was detected between milled screw-retained prostheses group and cement-retained prosthesis groups. CONCLUSION. Within the limitations of the study, it was concluded that the cement-retained designs do not always exhibit lower levels of stress than screw-retained designs. The internal adjustment of a cement-retained implant restoration is essential to achieve passive fit.

• 대한치과의사협회지
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• 제37권4호통권359호
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• pp.246-249
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• 1999

상악 전치부 임프란트 보철환자에서 screw-retained보철과 cement-retained 보철의 비교분석(Screw-retainde vs. cement-retained implant prosthesis in anterior edentulous area)

• The Journal of Advanced Prosthodontics
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• 제12권4호
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• pp.233-238
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• 2020

PURPOSE. This study aims to compare the marginal fitness of two types of implant-supported fixed dental prosthesis, i.e., cementless fixation (CL.F) system and cement-retained type. MATERIALS AND METHODS. In each group, ten specimens were assessed. Each specimen comprised implant lab analog, titanium abutment fabricated with a 2-degree tapered axial wall, and zirconia crown. The crown of the CL.F system was retained by frictional force between abutment and relined composite resin. In the cement-retained type, zinc oxide eugenol cement was used to set crown and abutment. All specimens were sterilized with ethylene oxide, immersed in Prevotella intermedia culture in a 50 mL tube, and incubated with rotation. After 48 h, the specimens were washed thoroughly before separating the crown and abutment. The bacteria that penetrated into the crown-abutment interface were collected by washing with 500 µL of sterile saline. The bacterial cell number was quantified using the agar plate count technique. The BacTiter-Glo Microbial Cell Viability Assay Kit was used to measure bacterial adenosine triphosphate (ATP)-bioluminescence, which reflects the bacterial viability. The t-test was performed, and the significance level was set at 5%. RESULTS. The number of penetrating bacterial cells assessed by colony-forming units was approximately 33% lower in the CL.F system than in the cement-retained type (P<.05). ATP-bioluminescence was approximately 41% lower in the CL.F system than in the cement-retained type (P<.05). CONCLUSION. The CL.F system is more resistant to bacterial penetration into the abutment-crown interface than the cement-retained type, thereby indicating a precise marginal fit.

• 대한치과보철학회지
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• 제50권4호
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• pp.318-323
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• 2012

임플란트 보철물은 유지방법에 따라 크게 나사 유지형 보철물(screw-retained prosthesis)과 시멘트 유지형 보철물(cement-retained prosthesis)로 나눌 수 있으며, 이들 장점을 고려하여 만든 나사-시멘트 유지형 보철물(SCRP: screw and cement retained implant prosthesis)이있다. 나사-시멘트 유지형 보철물은 임플란트 지대주와 상부 보철물 사이의 시멘트 층이 보철물 제작 과정에서 발생하는 여러 오차를 보상하여 수동적 적합을 얻을 수 있으며, 임상 및 기공 과정이 간단한 장점과 더불어 임플란트 보철의 유지 관리를 위해 필수적인 탈 부착(retrievability)이 가능하다. 본 증례에서는 완전 무치악 환자를 대상으로 상, 하악에 각각 9, 8개의 임플란트(US II, OSSTEM, Seoul, Korea)를 식립하고 나사 구멍이 순측으로 향하는 부위는 시멘트 유지형, 다른 부위는 나사-시멘트 유지형태를 사용하여 복합형태의 나사-시멘트 보철물(SCP: screw-cement prosthesis)을 제작하였으며 3년 간의 정기 검사에서 기능과 심미적으로 만족할 만한 결과를 얻어 이를 보고하고자 한다.

• The Journal of Advanced Prosthodontics
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• 제10권5호
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• pp.381-387
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• 2018

PURPOSE. Cement-retained implant prostheses can lack proper retrievability during repair, and residual cement can cause peri-implantitis. The purpose of this in vitro study was to evaluate the influence of abutment height and convergence angle on the retrievability of cement-retained implant prostheses with lingual slots, known as retrievable cement-type slots (RCS). MATERIALS AND METHODS. We fabricated six types of titanium abutments (10 of each type) with two different heights (4 mm and 6 mm), three different convergence angles ($8^{\circ}$, $10^{\circ}$, and $12^{\circ}$), a sloped shoulder margin (0.6 mm depth), a rectangular shape ($6mm{\times}6.5mm$) with rounded edges, and a rectangular ledge ($2mm{\times}1mm$) for the RCS. One monolithic zirconia crown was fabricated for each abutment using a dental computer-aided design/computer-aided manufacturing system. The abutments and crowns were permanently cemented together with dual-curing resin cement, followed by 24 hours in demineralized water at room temperature. Using a custom-made device with a slot driver and torque gauge, we recorded the torque ($N{\cdot}cm$) required to remove the crowns. Statistical analysis was conducted using multiple regression analysis and Mann-Whitney U tests (${\alpha}=.05$). RESULTS. Removal torques significantly decreased as convergence angles increased. Multiple regression analysis showed no significant interaction between the abutment height and the convergence angle (Durbin-Watson ratio: 2.186). CONCLUSION. Within the limitations of this in vitro study, we suggest that the retrievability of cement-retained implant prostheses with RCS can be maintained by adjusting the abutment height and convergence angle, even when they are permanently cemented together.

• 대한치과보철학회지
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• 제14권1호
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• pp.17-21
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• 1976

The author studied the gingival responses to some dental cements in the gingival sulcus around artificial crowns. Abutment preparation for full veneer crown was performed in the canines of the two dogs. The location of cervical margins was about 0.5mm. below the gingival crest. Niranium metal crowns were constructed for the teeth, and cemented with zinc phosphate cement or polycarboxy late cement. In the experimental groups the retained cements in the gingival sulucus were not removed, and in the control groups the cements were removed completely after cementation. The dogs were sacrificed at 3 weeks and 5 weeks respectively after cementation. The gingival responses to these cements were examined histologically. The findings were as follows. 1. There was severe inflammation in the gingiva where the cements had been retained in the gingival sulcus around artificial crowns. 2. There was more severe inflammation in the gingiva which had contacted with zinc phosphate cement than in the gingiva with polycarboxylate cement. 3. There was mild inflammation in the gingiva around the margins of Niranium crowns. 4. The retained cement around the margin of restoration should be completely removed after cementation.

• The Journal of Advanced Prosthodontics
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• 제7권3호
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• pp.207-213
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• 2015

PURPOSE. The purpose of this study was to examine the abutment screw stability of screw- and cement-retained implant-supported dental prosthesis (SCP) after simulated cement washout as well as the stability of SCP cements after complete loosening of abutment screws. MATERIALS AND METHODS. Thirty-six titanium CAD/CAM-made implant prostheses were fabricated on two implants placed in the resin models. Each prosthesis is a two-unit SCP: one screw-retained and the other cemented. After evaluating the passive fit of each prosthesis, all implant prostheses were randomly divided into 3 groups: screwed and cemented SCP (Control), screwed and non-cemented SCP (Group 1), unscrewed and cemented SCP (Group 2). Each prosthesis in Control and Group 1 was screwed and/or cemented, and the preloading reverse torque value (RTV) was evaluated. SCP in Group 2 was screwed and cemented, and then unscrewed (RTV=0) after the cement was set. After cyclic loading was applied, the postloading RTV was measured. RTV loss and decementation ratios were calculated for statistical analysis. RESULTS. There was no significant difference in RTV loss ratio between Control and Group 1 (P=.16). No decemented prosthesis was found among Control and Group 2. CONCLUSION. Within the limits of this in vitro study, the stabilities of SCP abutment screws and cement were not significantly changed after simulated cement washout or screw loosening.

• The Journal of Advanced Prosthodontics
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• 제14권3호
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• pp.162-172
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• 2022

PURPOSE. The present study aims to analyze the effect of abutment neck taper and types of cement on the amount of undetected remnant cement of cement-retained implant prostheses. MATERIALS AND METHODS. Three neck taper angles (53°, 65°, 77°) and three types of cement (RMGI: resin-modified glass ionomer, ZPC: zinc phosphate cement, ZOE: zinc oxide eugenol cement) were used. For each group, the surface percentage was measured using digital image and graphic editing software. The weight of before and after removing remnant cement from the abutment-crown assembly was measured using an electronic scale. Two-way ANOVA and Duncan & Scheffe's test were used to compare the calculated surface percentage and weight of remnant cement (α = .05). RESULTS. There were significant differences in remnant cement surface percentage and weight according to neck taper angles (P < .05). However, there were no significant differences in remnant cement surface percentage and weight on types of cement. No interaction was found between neck taper angles and types of luting cement (P > .05). The wide abutment with a small neck taper angle showed the most significant amount of remnant cement. And the types of luting cement did not influence the amount of residual cement. CONCLUSION. To remove excess cement better, the emergence profile of the crown should be straight to the neck taper of the abutment in cement-retained implant restoration.