• 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.

• 대한치과보철학회지
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• 제44권2호
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• pp.174-184
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• 2006

Purpose: Current trend in implant dentistry is changing from external connection to internal connection. To evaluate the splinting of external and internal connection implant on screw loosening, 2-units prosthesis was fabricated with BioPlant $System^(R)$ of external connection type and Lifecore STAGE-1 Single Stage Implant $System^(R)$ of internal connection type. Material and Method: Experimental group is classified into three groups. 1) $G_1-EE$: 2-units prosthesis was fabricated with two Bioplant $System^(R)$ of external connection type. 2) $G_1-EI$: 2-units prosthesis was fabricated with one BioPlant $System^(R)$ of external connection type and one Lifecore STAGE-1 Single Stage Implant $System^(R)$ of internal connection type. 3) $G_1-II$: 2-units prosthesis was fabricated with two Lifecore STAGE-1 Single Stage Implant $System^(R)$ of internal connection type. In fabricating 2-units prosthesis, two hexed abutments are recommended when two implants are installed parallel, otherwise one hexed abutment is used on major occlusal force area and one nonhexed abutment is used on the other area. Since it is rare to find two implants being parallel, it is hard to fabricate prosthesis with passive adaptation using two hexed abutments. It is much more difficult to acquire passive adaptation when using hex abutment compared to nonhex abutment. To evaluate the influence of hexed and nonhexed abutment on screw loosening, 2-units prosthesis was fabricated with hexed and nonhexed abutment. Experimental group is classified into three groups. 1) $G_2-HH$: 2-units prosthesis was fabricated with two hexed abutments. 2) $G_2-HN$: 2-units prosthesis was fabricated with one hexed abutment and one nonhexed abutment. 3) $G_2-NN$: 2-units prosthesis was fabricated with two nonhexed abutments. Result: The results of comparing the detorque value after loading on a each prosthesis periodically are as follows. 1. In splinting group of external and internal connection implant, $G_1-II$ group demonstrated the biggest detorque value, followed by $G_1-EI$ group and $G_1-EE$ group. 2. There is no notable significance between external connection implant of $G_1-EI$ group and $G_1-EE$ group and also no significance between internal connection implant of $G_1-EI$ group and $G_1-II$ group. 3. $G_2-HH$ group showed higher detorque value than $G_2-HN\;and\;G_2-NN$ group. From the results, we can concluded that using both external connection and internal connection implant together is clinically acceptable and in order to acquire a good passive adaptation in fabricating 2-units implant prosthesis we can use two nonhexed abutments.

• 대한치과보철학회지
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• 제35권4호
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• pp.767-780
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• 1997

One of the most common problems of implant prosthesis is the screw loosening of abutment screws. This brings on discomfort in mastication, inflammation in the peri-implant tissue due to poor oral hygiene and fracture of prosthesis or loss of osseointegration. To prevent screw loosening, appropriate implantation to direct the occlusal force to the long axis of the implant, accurate design of the superstructure, decrease of the occlusal table, and adequate torque on the abutment screw are necessary. In this study the screw loosening torque was evaluated in implants with dimples or flutes in the internal surface of abutment screw holes. The abutments were fastened with slot type and hexagonal type abutment screws and were sealed with vinyl poly siloxane impression and bite registration material respectively. The screw loosening torque was evaluated after 1,800 and 12,600 times loading under a loading machine. The results were as follows. 1. The flute form group showed significantly higher loosening torque compared to the dimple form group and the group with no inner surface treatment (p<0.05). 2. There was no statistical difference in loosening torque according to the sealing materials. 3. The loosening torque according to the types of abutment screw showed no significant difference. 4. The loosening torque was significantly higher after 1800 times loading compared to 12600 times loading(p<0.05). From the above results. it is thought that formation of a flute in the internal surface of the screw hole decreases the chance of screw loosening, but the sealing materials and types of abutment screw did not show significant difference in prevention of screw loosening.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제46권2호
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• pp.133-142
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• 2020

Objectives: In this study, we determined the incidence and pattern of screw loosening in patients who received dental implants. Materials and Methods: Patients who received implants between January 2008 and October 2013 and completed their prosthetic rehabilitation were evaluated for the incidence, frequency, and onset of screw loosening using dental charts and radiographs. The association between each factor and screw loosening was analyzed using the chi-square test and a multivariate analysis with binary logistic regression models (P<0.05). Results: Total 1,928 implants were placed in 837 patients (448 males, 389 females), whose follow-up period after loading varied from 0.25 to 70 months (mean period, 31.5 months). Screw loosening occurred in 7.2% of implants. Most cases occurred less than six months after loading. Among those, 22.3% experienced recurrent screw loosening. Screw loosening was most common in the molar region (8.5%) and frequently associated with an implant diameter of ≥5 mm (14.2%). External implant-abutment connections (8.9%) and screw-retained implant prostheses (10.1%) showed higher incidence of problems than internal implant-abutment connections and cement-retained implants, respectively. Screw loosening was most common in implant prostheses with single crowns (14.0%). Conclusion: Within the limits of the current study, we conclude that the incidence of screw loosening differs significantly according to the position of implant placement, the type of implant and manufacturer, implant diameter, the type of implant-abutment connection, the type of retention in the implant prosthesis, and the type of implant prosthesis.

• The Journal of Advanced Prosthodontics
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• 제7권5호
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• pp.375-379
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• 2015

PURPOSE. The purpose of this study was to evaluate the influence of tightening technique and the screw coating on the loosening torque of screws used for Universal Abutment fixation after cyclic loading. MATERIALS AND METHODS. Forty implants (Titamax Ti Cortical, HE, Neodent) (n=10) were submerged in acrylic resin and four tightening techniques for Universal Abutment fixation were evaluated: A - torque with 32 Ncm (control); B - torque with 32 Ncm holding the torque meter for 20 seconds; C - torque with 32 Ncm and retorque after 10 minutes; D - torque (32 Ncm) holding the torque meter for 20 seconds and retorque after 10 minutes as initially. Samples were divided into subgroups according to the screw used: conventional titanium screw or diamond like carbon-coated (DLC) screw. Metallic crowns were fabricated for each abutment. Samples were submitted to cyclic loading at $10^6$ cycles and 130 N of force. Data were analyzed by two-way ANOVA and Tukey's test (5%). RESULTS. The tightening technique did not show significant influence on the loosening torque of screws (P=.509). Conventional titanium screws showed significant higher loosening torque values than DLC (P=.000). CONCLUSION. The use of conventional titanium screw is more important than the tightening techniques employed in this study to provide long-term stability to Universal Abutment screws.

• 대한치과보철학회지
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• 제56권3호
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• pp.212-217
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• 2018

목적: 본 연구의 목적은 구치부 식립 임플란트에서 지대주 나사 풀림의 발생 빈도 및 지대주 나사 풀림에 영향을 주는 다양한 요인들을 후향적 연구를 통하여 평가하는 것이다. 대상 및 방법: 2013년 1월부터 2016년 1월까지 208명의 환자에서 구치부에 식립한 391개의 임플란트를 대상으로 하였다. 모든 수복물은 고정성으로 단일 혹은 연결 크라운, 브릿지로 제작되었으며, 임시 시멘트로 합착하였다. 전체 수복물 중 지대주 나사 풀림의 발생 빈도를 조사하였고, 성별, 보철물의 위치, 대합치, 보철물의 유형, 지대주 연결 유형, 매식체의 지름이 지대주 나사 풀림에 미치는 영향을 평가하였다. 결과: 2 - 5년의 관찰 결과, 총 29개(7.4%)의 임플란트에서 지대주 나사 풀림이 발생하였다. 최종 수복 후 지대주 나사 풀림이 발생하기까지 소요된 기간은 3개월부터 48개월(평균19.5개월)까지 다양하게 나타났으며, 이 중 3개의 임플란트에서 매식체의 파절이 발생되었다. 고려 요인들 중, 임플란트의 식립 위치에 따라 대구치(9.4%)와 소구치(2.6%)에서 통계적으로 유의한 차이를 보였으며(P < .019), 대합치에 따라 자연치(9.9%), 임플란트(1.0%), 가철성 보철물(0%)에서 유의한 차이를 보였다(P < .018). 다른 고려 요인에 따른 지대주 나사 풀림 발생 빈도는 통계적 유의성이 없었다. 결론: 구치부 임플란트 수복물에서 지대주 나사 풀림의 발생 빈도는 7.4%로 나타났다. 소구치보다 대구치에서 유의하게 높은 발생 빈도를 보였으며, 대합치에 따라서는 임플란트, 가철성 보철물과 비교 시 자연치에서 유의하게 높은 발생 빈도를 보였다.

• 구강회복응용과학지
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• 제19권2호
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• pp.125-137
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• 2003

The use of screw-retaind prosthesis on an osseointegrated implant is a popular treatment modality offering relative ease in the removal of the restoration. One of the complications associated with this modality is the loosening of the abutment and coping screws. Loosening of the screws results in patient dissatisfaction, frustration to the dentist and, if left untreated, component fracture. There are several factors which contribute to the loosening of implant components which can be controlled by the restorative dentist and lab technician. This article offers pratical solutions to minimize this clinical problem and describes the factors involved in maintaining a stable screw joint assembly. To avoid joint failure, adherence to specific clinical, as well as mechanical, parameters is critical. With respect to hardware, optimal tolerance and fit, minimal rotational play, best physical properties, a predictable interface, and optimal torque application are mandatory. In the clinical arena, optimal implant distribution; load in line with implant axis; optimal number, diameter, and length of implants; elimination of cantilevers; optimal prosthesis fit; and occlusal load control are equally important.

• 대한정형외과학회지
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• 제56권1호
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• pp.42-50
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• 2021

목적: 종양인공관절 주위 골절은 안정된 고정의 어려움과 골유합 후에도 골질 약화로 해리 및 재골절 위험이 많다. 피질골 지주 중첩 동종골 이식술을 종양인공관절 주위 골절에 적용하면 내고정도 쉽고, 골유합 기간도 단축되며, 합병증도 줄일 수 있을 것이라고 생각하였다. 본 연구는 종양인공관절 주위 골절 27예(30 골절)의 골절의 양상과 치료 후 재건 술식에 따른 생존율 및 합병증, 중첩 동종골 이식술 추가 여부에 따라 골유합 기간 및 기능적 결과가 차이가 있는지 분석하였다. 대상 및 방법: 골절 치료 시 판형 동종골 이식을 한 군 16예와 시행하지 않은 군 14예를 비교하였다. 분석항목은 종양인공관절 치환술부터 골절까지 기간, 골절의 양상, 골유합 기간 차이, 합병증, 및 기능적 결과를 기술하였다. 결과: 골절 양상은 unified classification system (UCS) B형이 21예(70.0%, 21/30)로 가장 많았으며 그 중 B1이 14예(46.7%, 14/30), B2가 1예(3.4%, 1/30), B3가 6예(20.0%, 6/30)였고 C형이 9예(30.0%, 9/30)였다. Kaplan-Meier 법에 의한 30 재건 부위의 5년, 10년 생존율은 각각 84.5%±4.18%, 42.2%±7.83%였다. 전체 30예의 골유합 기간은 평균 5.1개월(범위, 2.0-11.2개월)이었다. 동종골 이식군은 평균 3.5개월(범위, 2.0-6.26개월)로 고식적 고정군의 평균 7.2개월(범위, 4.0-11.2개월)보다 짧았다(p<0.0001). 최종 기능평가상 동종골 이식군은 평균 26.1점으로 고식적 고정군의 평균 20.9점보다 높았다(p<0.0001). 합병증은 4예로 모두 동종골을 사용하지 않은 군에서 있었다. 결론: 종양인공관절 주위 골절은 드물고 골유합도 비교적 잘 이루어지나 유합 후 합병증 최소화가 중요하다. 판형 중첩 동종골 이식술은 골유합 기간을 단축, 골질 증가, 해리위험성 감소 효과가 있으며 종양인공관절 주위 골절에 유용한 방법이다.

• 대한치과기공학회지
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• 제45권4호
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• pp.124-130
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• 2023

This study aims to describe the clinical experience of single and bridge crowns fabricated using a cementless screw-retained implant prosthesis system. In the case of single crown (#37), regular link (HDL) was used, and bridge crowns (#15~#24), (#26~#27), (#17~#14) (#24~#26) were fabricated by selecting regular link and short link considering the vertical height. One abutment was hex shaped to ensure that it could be mounted while preventing insertion and prosthesis rotation. The advantages of cementless implant prosthesis include shorter chair time and periodic care, strong retention with LINK abutment, safety from inflammation, bacterial infection, and complications due to peri-implant cement, and high patient satisfaction. Dentists should double-check the position of the implant fixture and dental technicians should continuously manage the fit of the link and prosthesis with digital equipment to reduce screw loosening and fractures.

• 대한치과보철학회지
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• 제43권5호
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• pp.671-683
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• 2005

Statement of problem: The most commonly reported problem associated with dental implant restoration is the loosening of the screws. Purpose: This study compared the efficacy of an implant system incorporating an anti-rotational locking sleeve(Anti-Rotating Inner Post Screw System(ARIPS-system)) with other, traditional implant systems as a means of minimizing vibration loosening. Materials and methods: Three implant systems were examined; the conventional external hex type, the ARIPS-system, and the internal taper type implant system 30 specimens(10 samples per group)were fabricated and each abutment screw was secured to the implant future with 32Ncm of torque force and loosening torque was measured using a Torque Gauge. The procedure was repeated 3 times, recording initial loosening torque each time. The re-tightened abutment screw was subjected to a cyclic load having a maximum forte of 200N and minimum of 20N at 2Hz over a period of 12,600 cycles. after which the loosening torque was measured. Measured values were calaulated for statistical analysis. Analysis of measured value was performed by 3 methods: (i) as a percentage average of the initial 3 loosening-torque values(initial loosening value) to the tightening torque of 32Ncm, (ii) as a percentage of the loosening torque value after a load of 200N(experimental value) to the initial loosening value, and (iii) as a percentage of the experimental value to the 32Ncm of tightening torque. The analyses shows the amount of initial loosening at the screw, loosening by repetitive load and the the final loosening value. Results: The results of this study were as follows (1) Percentage of initial loosening value to tightening-torque was increased in order of external hex, ARIPS-system and internal taper and all values between each groups showed statistical significance (p<0.05). (2) Percentage of experimental value to initial loosening value was increased in order of external hex, ARIPS-system and internal taper. Value of internal taper showed significant difference with those of external hex and ARIPS-system (p<0.05). (3) Percentage of experimental value to tightening torque was increased in order of external hex, ARIPS-system and internal taper and all values between each groups showed statistical significance (p<0.05). Conclusion: The results of the analysis of the final loosening level value, which are closely correlated to clinical use, show that the ARIPS-system can be a useful means of minimizing abutment screw loosening when compared to the external hex type system. Although further clinical studies need to be made, the ARIPS-system should be considered to maximize the long-term success of the implant prosthesis.