Effect of unilateral misfit on preload of retention screws of implant-supported prostheses submitted to mechanical cycling

Assunção, Wirley Gonçalves; Barão, Valentim Adelino Ricardo; Délben, Juliana Aparecida; Gomes, Érica Alves; Garcia, Idelmo Rangel

doi:10.1016/j.jpor.2010.05.002

Cited by 41 publications

(54 citation statements)

References 25 publications

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“…[10] The reported incident forces in molars ranged from 390 to 880 N, in premolars was 453 N, and in incisors was 222 N. Thus, a load of 400 N was used in the region of the premolar. [610]…”

Section: Discussionmentioning

confidence: 99%

“…[123456] The connection is achieved by means of bolts created by the union between the implant and the prosthetic component. [1345] The most frequently observed complication of screwed and cemented prostheses is loosening of the screw that leads to a misfit of the abutment to the implant after the prosthesis is in use.…”

Section: Introductionmentioning

confidence: 99%

“…[1345] The most frequently observed complication of screwed and cemented prostheses is loosening of the screw that leads to a misfit of the abutment to the implant after the prosthesis is in use. [13456] The combination of horizontal and vertical misfits may result in a gap leading to an increased area of bacterial accumulation, which complicates clean-up[78] and causes gingival inflammation due to the development of microflora in the gap region. Peri-implantitis and subsequent risks of bone resorption as well as posterior fracture of the screw can develop.…”

Section: Introductionmentioning

confidence: 99%

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Stability of external and internal implant connections after a fatigue test

et al. 2013

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Objective:The objective of this study was to compare the torque and detorque values of screw intermediates of external hexagon, internal hexagon, and Morse taper implants in single restorations before and after mechanical cycling.Materials and Methods:The study sample was divided into three groups (n = 10) as follows: group EH – external hexagon implant, group IH – internal hexagon implant, and group MT – Morse taper implant. Universal abutments were screwed on the implants, and metal crowns were cemented onto the abutment. The samples were submitted to a mechanical testing of 1 million cycles, with a frequency of 8 cycles per second under a 400 N load. The application and registration of the screw torque (T0) and detorque (T1) values of the intermediate were performed before and after the test. The results were statistically evaluated by analysis of variance (ANOVA) and Tukey's test (α = 0.05).Results:There was no difference between the values of T0 and T1 in the intra-group samples. However, the inter-group difference in T0 between the EH (12.8 N cm) and MT (18.6 N cm) groups and in T1 between the EH (10.4 N cm) and IH (13.8 N cm), EH and MT (19.4 N cm), and MT and IH (P = 0.001) groups were significant. The MT group showed a lower variation of T0 and T1.Conclusion:The internal implants, particularly MT, showed better stability in these cases when used for single restorations.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Stability of external and internal implant connections after a fatigue test

et al. 2013

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“…3 Upon tightening, the generated axial load between the abutment screws and the mating threads of the implant is called ''the preload.'' 21,22 When the preload in the screw joint is surpassed, overload can occur. 21 This overload could result in early implant failure by screw loosening or fracture.…”

Section: Introductionmentioning

confidence: 99%

Does Abutment Collar Length Affect Abutment Screw Loosening After Cyclic Loading?

Siadat

Pirmoazen

Beyabanaki

et al. 2015

Journal of Oral Implantology

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A significant vertical space that is corrected with vertical ridge augmentation may necessitate selection of longer abutments, which would lead to an increased vertical cantilever. This study investigated the influence of different abutment collar heights on single-unit dental implant screw-loosening after cyclic loading. Fifteen implant-abutment assemblies each consisted of an internal hexagonal implant were randomly assigned to 3 groups: Group1, consisting of 5 abutments with 1.5 mm gingival height (GH); Group2, 5 abutments with 3.5 mm GH; and Group3, 5 abutments with 5.5 mm GH. Each specimen was mounted in transparent auto-polymerizing acrylic resin block, and the abutment screw was tightened to 35 Ncm with an electric torque wrench. After 5 minutes, initial torque loss (ITL) was recorded for all specimens. Metal crowns were fabricated with 45° occlusal surface and were placed on the abutments. A cyclic load of 75 N and frequency of 1 Hz were applied perpendicular to the long axis of each specimen. After 500 000 cycles, secondary torque loss (STL) was recorded. One-way ANOVA analysis was used to evaluate the effects of abutment collar height before and after cyclic loading. One-way ANOVA showed that ITL among the groups was not significantly different (P = .52), while STL was significantly different among the groups (P = .008). Post-hoc Tukey HSD tests showed that STL values were significantly different between the abutments with 1.5 mm GH (Group1) and with 5.5 mm GH (Group3) (P = .007). A paired comparison t-test showed that cyclic loading significantly influenced the STL in comparison with the ITL in each group. Within the limitations of this study, it can be concluded that increase in height of the abutment collar could adversely affect the torque loss of the abutment screw.

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“…There are no clinical longitudinal studies demonstrating that the loss of screws can be attributed to misfit at abutment-implant interface 4 . The abutment-implant misfit does not influence the loss of screw torque 5,6 , but the advance in this misfit results in increasingly higher stress over prosthetic structures, abutment screws and peri-implant bone tissue 7 .…”

Section: Introductionmentioning

confidence: 99%

Microscopic evaluation of implant platform adaptation with UCLA-type abutments: in vitro study

Rodrigues

Tribst

Santis

et al. 2017

Rev. odontol. UNESP

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ResumoIntrodução: O ajuste entre a prótese e o implante é fundamental para determinar a longevidade do tratamento e manutenção do osso periimplantar. Objetivo: Avaliar o desajuste vertical entre diferentes infraestruturas metálicas e plataforma dos implantes, a fim de fornecer informação, para auxiliar na escolha do metal a ser utilizado. Material e método: O estudo utilizou componentes do tipo UCLA (N=40), com antirrotacional, foram divididos da seguinte forma: componentes usinados em titânio (n=10), componentes fundidos em titânio (n=10), níquel-cromo-titânio-molibdênio (n=10) e em níquel-cromo (n=10). Após o torque, as amostras foram analisados em estereomicroscópio. Para caracterização em MEV, foram utilizadas as amostras mais representativas, com maior e menor desajuste vertical. Resultado: Os dados foram analisados por média e desvio padrão e submetidos ao teste ANOVA ONE way, onde os grupos foram estatisticamente diferentes (p=<0,05), seguido do teste TUKEY. Conclusão: A escolha do infraestrutura influencia no valor do desajuste vertical, sendo que o grupo usinado em Ti apresentou o menor valor de desajuste, e o grupo fundido em Ni Cr o grupo com maior valor de desajuste vertical.Descritores: Prótese dentária; implante dentário. Abstract Introduction:The fit between abutment and implant is crucial to determine the longevity of implant-supported prostheses and the maintenance of peri-implant bones. Objective: To evaluate the vertical misfit between different abutments in order to provide information to assist abutment selection. Material and method: UCLA components (N=40) with anti-rotational system were divided as follows: components usinated in titanium (n=10) and plastic components cast proportionally in titanium (n=10), nickel-chromium-titanium-molybdenum (n=10) and nickel-chromium (n=10) alloys. All components were submitted to stereomicroscope analysis and were randomly selected for characterization by SEM. Result: Data were analyzed using mean and standard deviation and subjected to ANOVA-one way, where the groups proved to statistically different (p=<0.05), followed by Tukey's test. Conclusion: The selection of material influences the value of vertical misfit. The group machined in Ti showed the lowest value while the group cast in Ni Cr showed the highest value of vertical misfit.

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Effect of unilateral misfit on preload of retention screws of implant-supported prostheses submitted to mechanical cycling

Abstract: The unilateral misfit influenced the preload maintenance only before mechanical cycling. The mechanical cycling did not influence the torque reduction.

Cited by 41 publications

References 25 publications

Stability of external and internal implant connections after a fatigue test

Stability of external and internal implant connections after a fatigue test

Does Abutment Collar Length Affect Abutment Screw Loosening After Cyclic Loading?

Microscopic evaluation of implant platform adaptation with UCLA-type abutments: in vitro study

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