An In Vitro Analysis of Implant Screw Torque Loss With External Hex and Internal Connection Implant Systems

Piermatti, Jack; Yousef, Hoda; Luke, Allyn; Mahevich, R.; Weiner, Saul

doi:10.1097/01.id.0000245440.09464.48

Cited by 85 publications

(122 citation statements)

References 11 publications

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“…The load was applied with a metal cylinder with 4 mm in diameter. The machine was set to work at a frequency of 101 cycles per minute, simulating to the human chewing frequency 26 (Fig. 2).…”

Section: Methodsmentioning

confidence: 99%

Screw loosening of different UCLA-type abutments after mechanical cycling

Junqueira¹,

Ribeiro²,

Faria³

et al. 2013

Braz. J. Oral Sci.

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Aim: To evaluate the loss of applied torque (detorque) values in cast and pre-machined abutments for external hex abutment/implant interface of single implant-supported prostheses subjected to mechanical cycling. Methods: Ten metal crowns were fabricated using two types of UCLA abutments: cast and pre-machined with metal base in NiCrTi alloy and tightened to regular external hex implants with a titanium alloy screw, with an insertion torque of 32 N.cm, measured with a digital torque gauge. Samples were embedded with autopolymerizing acrylic resin in a stainless steel cylindrical matrix, and positioned in an electromechanical machine. Dynamic oblique loading of 120 N was applied during 5 x 10 5 cycles. Then, each sample was removed from the resin and detorque values were measured using the same digital torque gauge. The difference of the initial (torque) and final (detorque) measurement was registered and the results were expressed as percentage of initial torque. The results of torque loss were expressed as percentage of the initial torque and subjected to statistical analysis by the Student's t-test (p<0.05) for comparisons between the test groups. Results: Statistical analysis demonstrated that mechanical cycling reduced the torque of abutments without significant difference between cast or pre-machined UCLA abutments (p=0.908). Conclusions: Within the limitations of this in vitro study, it may be concluded that the mechanical cycling, corresponding to one-year use, reduced the torque of the samples regardless if cast or pre-machined UCLA abutments were used.

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Section: Methodsmentioning

confidence: 99%

Screw loosening of different UCLA-type abutments after mechanical cycling

Junqueira¹,

Ribeiro²,

Faria³

et al. 2013

Braz. J. Oral Sci.

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show abstract

“…This indicated that there was mechanical resistance in the lower lobe. Piermatti et al 25 studied the shape of the implant abutment screw and the stability of the connection; they reported that the torque decreased when a thicker, special form of screw was used. In this study, we used screws with a thread of 2.0 mm and a long upper part with a thickness of 2.5 mm; this could have stabilized the connection between the implant abutment and the fixture, and thus, prevented differences in the removal torques.…”

Section: Discussionmentioning

confidence: 99%

Influence of internal connection length on screw loosening in internal connection implants

Kim

Park

Choi

et al. 2017

J Korean Acad Prosthodont

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“…The implant-abutment connection stability is also influenced by factors such as component fit, machining accuracy, saliva contamination, and screw preload. [1][2][3][4][5][6][7][8] Most in vitro studies, [9][10][11][12] with the exception of one, 13 have demonstrated that internal connections are more mechanically stable than external flat (hex-type) connections. Loosening of abutment screws, particularly with the "classic" external-hex implant systems, has been a well-known technical problem, occurring mainly during the first 2 years after delivery of the crown.…”

mentioning

confidence: 99%

Abutment screw loosening in single-implant restorations: A systematic review

Theoharidou

Petridis²,

Tzannas³

et al. 2009

The Journal of Prosthetic Dentistry

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3). Conclusion: The results show that abutment screw loosening is a rare event in singleimplant restorations regardless of the geometry of implant-abutment connection, provided that proper antirotational features and torque are employed. INT J ORAL MAXILLOFAC IMPLANTS 2008;23:681-690Key words: implant complications, implant geometry, meta-analysis, screw loosening, single implants T he stability of the connection between different implant parts is important for the overall success of the reconstruction. This is especially true for singletooth restorations, where a strong interlock between the abutment and implant is necessary. Various mechanisms have been proposed to connect the dental implant abutment to the implant body. Different systems vary in connection geometry, materials, and overall screw mechanics. The implant-abutment connection stability is also influenced by factors such as component fit, machining accuracy, saliva contamination, and screw preload. [1][2][3][4][5][6][7][8] Most in vitro studies, [9][10][11][12] with the exception of one, 13 have demonstrated that internal connections are more mechanically stable than external flat (hex-type) connections. Loosening of abutment screws, particularly with the "classic" external-hex implant systems, has been a well-known technical problem, occurring mainly during the first 2 years after delivery of the crown. [14][15][16][17] The stability of the external implant-abutment connection was subsequently improved by altering the screw alloys and their surfaces and applying proper torque values to establish higher initial preloads. 3,[18][19][20][21]

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An In Vitro Analysis of Implant Screw Torque Loss With External Hex and Internal Connection Implant Systems

Abstract: It may be concluded from this study that although internal connections are clinically favored, this study did not show any advantage relative to screw loosening. However, screw design may be a significant factor in loosening of the joint.

Cited by 85 publications

References 11 publications

Screw loosening of different UCLA-type abutments after mechanical cycling

Screw loosening of different UCLA-type abutments after mechanical cycling

Influence of internal connection length on screw loosening in internal connection implants

Abutment screw loosening in single-implant restorations: A systematic review

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