scholarly journals Effects of cyclic loading on screw loosening, vertical misfit, and microleakage at the fixture-angulated abutment interface

2021 ◽  
Vol 6 (4) ◽  
pp. 1-7
Author(s):  
N Naseri ◽  
◽  
A Babasafari ◽  
E Jalalian ◽  
A Mazaheri ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Screw Loosening

Effect of implant abutment connection designs, and implant diameters on screw loosening before and after cyclic loading: In-vitro study

2019 ◽  
Vol 35 (11) ◽  
pp. e265-e271 ◽  
Author(s):  
Sara Reda Sammour ◽  
Mohamed Maamoun El-Sheikh ◽  
Attiah Aly El-Gendy
Keyword(s):  
Cyclic Loading ◽  
In Vitro Study ◽  
Vitro Study ◽  
Screw Loosening ◽  
Implant Abutment ◽  
Before And After

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

2015 ◽  
Vol 41 (S1) ◽  
pp. 346-351 ◽  
Author(s):  
Hakimeh Siadat ◽  
Salma Pirmoazen ◽  
Elaheh Beyabanaki ◽  
Marzieh Alikhasi
Keyword(s):  
Cyclic Loading ◽  
Paired Comparison ◽  
Acrylic Resin ◽  
Screw Loosening ◽  
Ridge Augmentation ◽  
Torque Wrench ◽  
Before And After ◽  
Torque Loss ◽  
One Way Anova ◽  
Abutment Screw

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.

scholarly journals Effect of Cyclic Loading on Abutment Screw Loosening in Angled Implant AbutmentsAn In-vitro Study

2019 ◽  
Author(s):  
Syed Ershad Ahmed ◽  
Chitra Shankar Krishnan ◽  
Jayashree Mohan ◽  
Parithimar Kalaignan
Keyword(s):  
Cyclic Loading ◽  
In Vitro Study ◽  
Vitro Study ◽  
Screw Loosening ◽  
Abutment Screw

Abutment Screw Loosening and Bending Resistance of External Hexagon Implant System after Lateral Cyclic Loading

2004 ◽  
Vol 6 (3) ◽  
pp. 157-164 ◽  
Author(s):  
Ameen Khraisat ◽  
Osama Abu-Hammad ◽  
Najla Dar-Odeh ◽  
Awni M. Al-Kayed
Keyword(s):  
Cyclic Loading ◽  
Screw Loosening ◽  
Bending Resistance ◽  
Implant System ◽  
Abutment Screw

Screw Loosening in an In Vitro Mid Fibular Osteotomy Model under Dynamic Loading Conditions

2000 ◽  
Vol 21 (10) ◽  
pp. 849-851 ◽  
Author(s):  
Aaron K. Graham ◽  
Daniel P. Hess ◽  
Heidi M. Stephens
Keyword(s):  
Cyclic Loading ◽  
Screw Fixation ◽  
Screw Loosening ◽  
Fibular Fracture ◽  
Torque Measurements ◽  
Breakaway Torque ◽  
Excessive Load ◽  
Viable Approach ◽  
Dynamic Loading Conditions

The purpose of this study was to evaluate the effect of cyclic loading on screw fixation in an experimental bone plating model. The test specimens consist of plated porcine fibulae subjected to cyclic compressive, bending and torsional loading. Breakaway torque measurements of orthopedic screws are found to be significantly less than the screws tightening torque. The breakaway torque for a given screw and tapped bone hole is found to be consistent after repeated tightening, and is proposed as a viable approach to quantify bone screw loosening. After cyclic loading at moderate levels no screw loosening was identified, but instead an apparent paradoxical tightening, as observed in breakaway torque measurements of the screws. Cyclic loading of a plated fibular fracture was not found to cause screw loosening unless accompanied by gross failure as found under excessive load levels.

scholarly journals Can cavity-based pedicle screw augmentation decrease screw loosening? A biomechanical in vitro study

2020 ◽  
Author(s):  
Hans-Joachim Riesner ◽  
Thomas R. Blattert ◽  
Renate Krezdorn ◽  
Simone Schädler ◽  
Hans-Joachim Wilke
Keyword(s):  
Cyclic Loading ◽  
Pedicle Screw ◽  
Pedicle Screws ◽  
In Vitro Study ◽  
Complex Loading ◽  
Control Group ◽  
Slight Reduction ◽  
Screw Loosening ◽  
Screw Augmentation

Abstract Purpose In an osteoporotic vertebral body, cement-augmented pedicle screw fixation could possibly be optimized by the creation of an initial cavity. The aim of this study is to compare three test groups with regard to their loosening characteristics under cyclic loading. Methods Eighteen human, osteoporotic spine segments were divided in three groups. Flexibility tests and cyclic loading tests were performed with an internal fixator. The screws were fixed after creation a cavity and with cement (cavity-augmented group), without cavity and with cement (augmented group), and without cavity and without cement (control group). Cyclic loading up to 100,000 cycles was applied with a complex loading protocol. Screw loosening was measured with flexibility tests after implantation and after cyclic loading. Cement distribution was visualized from CT scans. Results In all groups, range of motion increased during cyclic loading, representing significant screw loosening after 100,000 cycles. In both augmented groups, screw loosening was less pronounced than in the control group. The cavity-augmented group showed only a slight tendency of screw loosening, but with smaller variations compared to both other groups. This may be explained with a trend for a more equal and homogeneous cement volume around each tip for the cavity-augmented group. Conclusion This study demonstrated that creating a cavity may allow a more equal fixation of all pedicle screws with slight reduction of loosening. However, augmentation only through a cannulated screw is almost equivalent, if care is taken that enough cement volume can be pushed out around the tip of the screw.

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