Reverse Torque Values of Abutment Screws After Dynamic Loading: Effects of Sealant Agents and the Taper of Conical Connections

Ozdiler, Arda; Dayan, Çağatay; Gençel, Burç; Ozkol, Gulbahar Isık

doi:10.1563/aaid-joi-d-19-00228

“…Other authors have reported results consistent with ours [ 20 , 26 ]. On the other hand, Ozdiler et al [ 27 ] reported a higher percentage loss of RTV in the sealing silicone gel group than in the other groups, with a significant difference. Notably, the authors only registered the RTV after cyclic loading.…”

Section: Discussionmentioning

confidence: 97%

Preload and Removal Torque of Two Different Prosthetic Screw Coatings—A Laboratory Study

Coelho,

Mendes,

Mendes

et al. 2024

Materials

0

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This study aimed to evaluate the effect of two coating materials, a silicone sealing gel and a polytetrafluoroethylene (PTFE) tape, on the screw preload and removal torque value (RTV) to develop strategies to prevent prosthetic screw loosening. We examined 45 complexes comprising an implant, abutment, and prosthetic screw, of which 15 samples were uncoated, 15 were coated with GapSeal® (Hager & Werken GmbH & Co., Duisburg, Germany), and 15 were coated with PTFE tape (MIARCO®, Valencia, Spain). The screws were tightened to register the preload and then untightened to register the RTV. The preload values showed a statistically significant difference only in the PTFE group, suggesting that this lubricant negatively affects the preload. The RTVs showed statistically significant differences among all groups, with the GapSeal® group and PTFE group showing the highest and lowest values, respectively. It can be concluded that the application of the PTFE tape on the screw significantly reduced the preload and RTV. The silicone sealing gel did not affect the preload but increased the RTV. Therefore, the use of GapSeal® should be considered to prevent prosthetic screw loosening, while the use of PTFE tape should be avoided.

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“…Different methodology and variations in the form of contamination (for saliva; natural vs. artificial and for chlorhexidine; gel vs. liquid; wettability) and concentration may also account for differences in results between studies. In addition, the lack of simulating oral condition seems to be an effective factor for variation in reported results [18,26,27]. Despite the relatively high risk of blood and fluoride contamination of the abutment screw in clinical practice, a few studies on blood and fluoride contamination of the abutment screw have been reported in the literature.…”

Section: Discussionmentioning

confidence: 99%

“…Different methodology and variations in the form of contamination (for saliva; natural vs. artificial and for chlorhexidine; gel vs. liquid; wettability) and concentration may also account for differences in results between studies. In addition, the lack of simulating oral condition seems to be an effective factor for variation in reported results [ 18 , 26 , 27 ].…”

Section: Discussionmentioning

confidence: 99%

An In Vitro Study of Fluid Contaminations Influences on Reverse Torque Values of Implant-Abutment Connections

Yang

¹

,

Qin

²

,

Guo

³

et al. 2022

BioMed Research International

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Purpose. To examine the effects of fluid contamination on the reverse torque value (RTV) of abutment screws. 484 titanium fixtures were mounted into the stainless-steel holders. Methods. 11 groups (44 specimens in each group) of implants were mounted in acrylic resin. Ten groups of fixture screw holes were contaminated with chlorhexidine, saliva, blood, fluoride, or combination groups, and one group served as a control without contamination. To simulate the oral environment, samples were subjected to thermal cycling and cyclic loading. Results. The RTV means were less than the initial torque in both control and contamination groups. The maximum RTV mean was observed in the fluoride group ( 26.00 ± 1.02 Ncm). In other groups, this rate for control, blood, saliva, and chlorhexidine groups were 18.00 ± 1.78 Ncm, 22.12 ± 1.56 Ncm, 21.56 ± 1.43 Ncm, and 21.89 ± 1.02 Ncm, respectively. In combination groups, the maximum RTV mean was observed in the saliva+CHX group ( 23.89 ± 1.92 Ncm). In other combination groups, this rate for the blood+CHX, blood+saliva, saliva+fluoride, fluoride+CHX, and fluoride+blood groups were 22.56 ± 1.73 Ncm, 22.00 ± 1.54 Ncm, 20.11 ± 1.58 Ncm, 23.51 ± 1.19 Ncm, 21.02 ± 1.38 Ncm, and 20.11 ± 1.58 Ncm, respectively. The RTV was statistically significant ( p < 0.05 ) for the contamination groups (except saliva) and combination groups compared to the control group. There is no statistically significant difference ( p > 0.05 ) between the reverse torque value mean of the blood and saliva groups and between that of the fluoride and chlorhexidine groups. Conclusion. Implant-abutment specimens are suggested to be placed in a saliva environment and should be subjected to cyclic loading.

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The effect of fabrication procedures and thermomechanical loading on the structural properties of screw‐retained metal‐ceramic implant restorations: An in vitro study

Mohebbi,

Habibzadeh,

Alikhasi

et al. 2024

Journal of Prosthodontics

0

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PurposeMetal‐ceramic screw‐retained implant restorations persist as a fundamental choice in specific clinical scenarios. Little is known about the effects of fabrication steps and aging on their structural properties. This study aimed to investigate how laboratory fabrication procedures and thermomechanical loading affect the structural properties of screw‐retained metal‐ceramic implant restorations.Materials and MethodsTen screw‐retained metal‐ceramic restorations were conventionally cast using UCLA chromium‐cobalt overcast abutments. After 500 cycles of thermocycling and 500,000 cycles of mechanical loading, changes in connection dimensions and rotational freedom (RF) were measured and compared at various fabrication steps and post‐thermomechanical loading. A generalized estimating equations (GEE) model was employed to analyze trends across the studied time points within the fabrication stage and after thermomechanical loading, with LSD post‐hoc tests applied for pairwise comparisons. The level of significance was set at α = 0.05.ResultsSignificant changes were observed across the analyzed time points: the average hexagonal side length (L) decreased (p < 0.001), and the average hexagonal angle deformation (P) increased, with notable differences observed in most comparisons between different fabrication steps (p < 0.001). Short (T1) and long (T2) diagonals of the hexagon showed downward trends (p < 0.001), while concentricity (O) and RF increased (p < 0.001), except between porcelain firing and loading steps for RF (p = 0.637). Casting had the greatest impact on variations in O (93.33%), T1 (88.88%), and T2 (45%), while porcelain firing significantly affected L (71.42%), P (71.42%), with the greatest effect on RF (75.32%).ConclusionsThe fabrication processes and simulated clinical use adversely impacted the structural integrity and RF of abutments in screw‐retained chromium‐cobalt overcast implant restorations.

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Reverse Torque Values of Abutment Screws After Dynamic Loading: Effects of Sealant Agents and the Taper of Conical Connections

Cited by 4 publications

References 33 publications

Preload and Removal Torque of Two Different Prosthetic Screw Coatings—A Laboratory Study

Preload and Removal Torque of Two Different Prosthetic Screw Coatings—A Laboratory Study

An In Vitro Study of Fluid Contaminations Influences on Reverse Torque Values of Implant-Abutment Connections

The effect of fabrication procedures and thermomechanical loading on the structural properties of screw‐retained metal‐ceramic implant restorations: An in vitro study

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