The Role of Implant/Abutment System on Torque Maintenance of Retention Screws and Vertical Misfit of Implant-Supported Crowns Before and After Mechanical Cycling

Jorge, Juliana Ribeiro Pala; Barão, Valentim Adelino Ricardo; Délben, Juliana Aparecida; Assunção, Wirley Gonçalves

doi:10.11607/jomi.2727

Cited by 57 publications

(75 citation statements)

References 37 publications

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“…The SEM images showed no significant differences between the three groups, what concurs with the results of a SEM study where no difference was observed between RP and PS groups, in relation to the screw deformation (13). Seemingly, the loss of torque values in this study was not harmful to the implant/abutment junction, but there is no minimum value of torque loss for appropriate implant-supported prostheses performance (21).…”

Section: Discussionsupporting

confidence: 88%

“…Some studies evaluated the reverse torque and loosening of abutment retaining screw, (16,(18)(19)(20)(21), but none of these studies evaluated the loosening and reverse torque in platform switching connections and external hexagon implants. The results of the current study corroborate the findings in literature regarding reverse torque values found in implant/abutment connections with external hexagon after mechanical cycling test, as found by Cibirka et al (18), for RP and WP groups.…”

Section: Discussionmentioning

confidence: 99%

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Effect of Mechanical Cycling on Screw Torque in External Hexagon Implants with and without Platform Switching

et al. 2015

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This in vitro study evaluated the effect of mechanical cycling on the torque of retaining screw in external hexagon implants with platform switching (PS), regular platform (RP) and wide platform (WP). A total of 30 specimens were equally divided into 3 groups: PS, PR and WP. Each specimen was prepared with implants: 3.75 x 10 mm for RP group and 5.0x10 mm for PS and WP groups and its respective abutment with 32 Ncm torque. All groups were subjected to 10 6 cycles with 100 N (corresponding to about 40 months of chewing). The results were obtained with the reverse torque of each specimen and data were evaluated using ANOVA and Tukey test (p<0.05). The PS group showed statistically significant difference in screw removal torque (30.06±5.42) compared with RP (23.75±2.76) and WP (21.32±3.53) (p<0.05) groups; the RP and WP groups showed no statistically significant difference between them. It was concluded that the PS group showed higher reverse torque value, suggesting lower susceptibility of the abutment screw loosening.

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Section: Discussionsupporting

confidence: 88%

Section: Discussionmentioning

confidence: 99%

Effect of Mechanical Cycling on Screw Torque in External Hexagon Implants with and without Platform Switching

et al. 2015

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“…This was to take the so-called "settling effect" into account. Jorge et al 16) reported that when an unused abutment screw is tightened, the metals settle together over the space of a few minutes. Therefore, in our study, the implant system was left for 5 min after tightening.…”

Section: Experimental Apparatus and Methodsmentioning

confidence: 99%

“…There have been clinical studies 2,3) , as well as numerous basic research studies [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] on abutment screw looseness, and reasons for looseness that have been put forward include insufficient fastening torque of the screw, unfitted components, inappropriate direction or position of implant placement, and poor occlusal status [4][5][6][7][8][9][10][11][12][13][14][15][16][17] . Looseness of the abutment screw causes poor fit of the superstructure, and can lead to fracture of the abutment screw and superstructure damage or detachment, as well as fracture of the implant or resorption of the periimplant bone.…”

Section: Introductionmentioning

confidence: 99%

Abutment screw loosening of endosseous dental implant body/abutment joint by cyclic torsional loading test at the initial stage

Katsuta

Watanabe

2015

Dent. Mater. J.

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Cyclic torsional loading tests were carried out in the laboratory using various implant systems, in order to clarify differences between the systems in loosening of abutment screws. Six samples from six commercially available abutment systems were used, giving a total of 36 samples. Four of the systems used internal connections, and two used external connections. The abutment screw for each system was tightened to a torque value specified by the manufacturer, and after 5 min, the loosening torque was measured using a digital torque meter. Measurements were taken twice, and a second measurement was taken as a reference value. A cyclic torsional loading test with 100,000 cycles was performed on the sample, and the loosening torque was again measured after the test. In conclusion, loosening of the abutment screw occurred as a result of cyclic torsional loading, and the degree of loosening varied with each implant system.

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“…The crowns were torqued to the implants (32 N.cm), according to manufacturer's recommendation, using a hexagonal wrench. After 3 min, the screw was retightened to the same torque to minimize embedment relaxation 23 . The placement torque was measured by the digital torquemeter with a 0.1 precision.…”

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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The Role of Implant/Abutment System on Torque Maintenance of Retention Screws and Vertical Misfit of Implant-Supported Crowns Before and After Mechanical Cycling

Cited by 57 publications

References 37 publications

Effect of Mechanical Cycling on Screw Torque in External Hexagon Implants with and without Platform Switching

Effect of Mechanical Cycling on Screw Torque in External Hexagon Implants with and without Platform Switching

Abutment screw loosening of endosseous dental implant body/abutment joint by cyclic torsional loading test at the initial stage

Screw loosening of different UCLA-type abutments after mechanical cycling

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