Effect of abutment screw length and cyclic loading on removal torque in external and internal hex implants

Mohammed, Hnd Hadi; Lee, Jin-Han; Bae, Ji Myung; Cho, Hye Won

doi:10.4047/jap.2016.8.1.62

Cited by 17 publications

(26 citation statements)

References 23 publications

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“…These results are similar to those of several studies. Mohammed et al [17] reported that the post-loading RTVs of internal hex implants were significantly lower than the initial RTVs after 16,000 cycles and Cibirka et al [26] found decreasing RTVs in the internal hexagon of Nobel Biocare implants after 5 million cycles of fatigue testing. The decrease in RTVs after cyclic loading can be explained by the micromovement of the joint connection or progressive settling effect from functional loading [33].…”

Section: Discussionmentioning

confidence: 99%

“…It causes the two surfaces to come closer together and leads to axial displacement. This axial displacement causes the length of the abutment screw to shorten, diminishing the screw preload [17]. The settling effect is the main cause of screw loosening.…”

Section: Introductionmentioning

confidence: 99%

“…The degree of settling depends on the surface roughness, surface hardness, and magnitude of the tightening torque and of the occlusal loading force [16]. On the one hand, the settling effect [17] causes the axial displacement leading to the decrease of the screw preload. On the other hand, the axial displacement causes the cone connection surface adaptation providing frictional resistance and screw-joint stability [7, 8].…”

Section: Introductionmentioning

confidence: 99%

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Removal torque pattern of a combined cone and octalobule index implant-abutment connection at different cyclic loading: an in-vitro experimental study

2019

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BackgroundDespite the high survival rate of dental implants, screw loosening is frequently reported. Screw loosening can cause a misfit of the implant-abutment connection leading to peri-implantitis or abutment screw fracture. Therefore, studies about related factors and mechanism of screw loosening are needed. The aim of this study was to evaluate the decreasing pattern of removal torque values (RTVs) of a combined cone and octalobule index implant-abutment connection under different numbers of mechanical loading cycles.Materials and methodsThe study was performed in accordance with ISO 14801:2007. Eighty-four implants with the combined cone and octalobule index implant-abutment connection (PW Plus dental implant system, PW Plus Company) were used. All abutment screws were tightened 30 N cm twice with a 10-min interval. The control group was without cyclic loading and the experimental groups underwent different numbers of loading cycles until 2,000,000 cycles. Then, the abutment screws of all samples were untightened to measure the RTVs. The data were analyzed using ANOVA and Tukey’s HSD test.ResultsThe RTVs of the control group decreased 7.78% compared to the insertion torque. All experimental groups from 50,000 to 2,000,000 cycles showed significant decreases in RTVs compared to the control group (P < 0.05). RTVs in the group of 50,000 cycles to 1,800,000 cycles did not change significantly, but there was a significant reduction of RTVs in the group of 2,000,000 cycles when compared to the group of 50,000 cycles (P < 0.05).ConclusionsAccording to the setting condition for the fatigue test complied to ISO 14801:2007, the RTVs of the combined cone and octalobule index implant-abutment connection reduced significantly after 50,000 cycles and did not change significantly until 2,000,000 cycles.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Removal torque pattern of a combined cone and octalobule index implant-abutment connection at different cyclic loading: an in-vitro experimental study

2019

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“…Reduction in the RTV compared to the tightening torque is a result of embedment relaxation [24]. When abutment screw is subjected to torque application, micromovements between the screw and the internal surface of implant occur and the irregularities on the screw surface are flattened [25]. Such a wear between the surfaces in contact with each other approximates the metal surfaces.…”

Section: Discussionmentioning

confidence: 99%

Effect of Angle and Type of Customized Abutment (Castable & Cast-to) on Torque Loss and Fracture Resistance After Cyclic Loading

Shirazi¹,

Memarian²,

Alikhasi³

et al. 2018

TODENTJ

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Background: Implant placement with more than 25° angle and use of customized abutments are still challenging in implant dentistry. Also, casting is still the most commonly used method for fabrication of customized abutments. Objective: This study evaluated the effect of angulation and type of abutment (castable and cast-to) on torque loss and fracture resistance after cyclic loading. Methods: Two implants were mounted with 0 and 30° angle on a gypsum model. Castable and Cast-to abutments were casted by cobalt-chromium alloy on each implant (10 samples in 4 groups). Rotational freedom was measured by a video-measuring microscope. The reverse torque values before and after cyclic loading (500,000 cycles) were measured by a digital torque-meter. Abutments were subjected to fracture resistance test in a universal testing machine. Data were analyzed using the Kruskal Wallis, two-way ANOVA and repeated measures tests. Results: Difference between castable and cast-to abutments regarding rotational freedom was not significant. Torque loss in castable abutments was significantly greater than cast-to abutments before and after cyclic loading (P < 0.05). The effect of abutment angle on torque loss before and after cyclic loading was not significant. Conclusion: Irrespective of the abutment angle, torque loss was significantly higher in castable groups. Considering the high fracture resistance, abutment fractures were not clinically an issue.

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“…Além disso, a manifestação das cargas biomecânicas nos implantes dentais (momentos, tensão e pressão) controla a saúde da interface osso-implante a longo prazo (MISCH, 2015). (ARAT BILHAN et al, 2015;AYLLÓN et al, 2014a;BICUDO et al, 2016;CHEN et al, 2015;GHADIRI et al, 2015;HERNANDEZ-RODRIGUEZ et al, 2015;JAMSHIDINIA et al, 2015;KAYABAŞI et al, 2006;LIN et al, 2009;MACEDO et al, 2017;MINATEL et al, 2017;MOHAMMED et al, 2016;PRADOS-PRIVADO et al, 2017;SANTIAGO et al, 2016b;TOPKAYA;SOLMAZ, 2015;WOLFF et al, 2014 BILHAN et al, 2015;BORDIN et al, 2015;CHUN et al, 2002;DJEBBAR et al, 2010;HERNANDEZ-RODRIGUEZ et al, 2015;ILIES et al, 2008;KAYABAŞI et al, 2006;KOHN, 1991;MACEDO et al, 2017;MINATEL et al, 2017;PAN et al, 2015;PRADOS-PRIVADO et al, 2015;ŞAHIN;ÇEHRELI;YALÇIN, 2002;SANIVARAPU et al, 2016;SHEMTOV-YONA et al, 2014a, 2014cSKALAK, 1983 De acordo com Dieter (1981), os fatores básicos necessários para causar falha devido fadiga são:…”

Section: Introductionunclassified

Análise de fadiga em próteses odontológicas implanto-suportada sob carregamento multiaxiais.

Losada¹

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Dental prostheses are structures that restore the masticatory function and replace damaged dental components. Most studies on dental prostheses involve that classical analytical methods of structure analysis are infeasible and situations in which experimentation is difficult. These prostheses, under real conditions of cyclic loading (chewing), are repeatedly subjected to cyclic multiaxial stress states. In this sense, the cyclical nature of the loading, to which the components of the prosthesis are submitted, suggests that the fatigue failure mode has greater relevance in this type of structure. The development of computation and the increase of processing capacities have allowed greater implementation of numerical methods, such as Finite Element Methods (FEM). Through this method (FEM) it is performed the modeling of the mechanical behavior which is adjusted to the physical reality of the involved biomechanical factors. In a bibliographical review, it was verified that most of the books and articles found do not present detailed information about the prediction of life based on analyzes of multiaxial fatigue that use the FEM to calculate the dental prostheses. The objective of this research was to propose a computational numerical model using the FEM to evaluate the life to the fatigue in dental prostheses submitted to multiaxial loads. For this, we used the manipulation of acquired images, normative experimental tests, Finite Element analysis (FEA) in the prediction of life to the fatigue applied in either uniaxial or multiaxial loading, the counting of the fatigue damage in multiaxial amplitude variable loading, optimization and implementation of the subroutine for the APDL-MATLAB interfaces. The results showed that, through the techniques of image data acquisition (Micro-CT) and mechanical measurements combined with numerical methods, it is possible to model a complex structure such as a dental prosthesis.

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Effect of abutment screw length and cyclic loading on removal torque in external and internal hex implants

Cited by 17 publications

References 23 publications

Removal torque pattern of a combined cone and octalobule index implant-abutment connection at different cyclic loading: an in-vitro experimental study

Removal torque pattern of a combined cone and octalobule index implant-abutment connection at different cyclic loading: an in-vitro experimental study

Effect of Angle and Type of Customized Abutment (Castable & Cast-to) on Torque Loss and Fracture Resistance After Cyclic Loading

Análise de fadiga em próteses odontológicas implanto-suportada sob carregamento multiaxiais.

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