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. 2022 Jun 24;12(1):10797.
doi: 10.1038/s41598-022-14791-w.

Evaluation the loosening of abutment screws in fluid contamination: an in vitro study

Fei Sun  1 , Wei Cheng  1 , Bao-Hong Zhao  2 , Gui-Qiu Song  1 , Zeng Lin  3
Affiliations

Evaluation the loosening of abutment screws in fluid contamination: an in vitro study

Fei Sun et al. Sci Rep. .

Abstract

Screw loosening is one of the most common clinical problems of dental implants. Research on the influencing factors of screw loosening is very important to prevent screw loosening. The purpose of this in vitro study was to evaluate the influence of liquid contamination on the screw loosening. According to the contamination condition, forty-five abutment screws were divided into three groups (n = 15): no contamination, artificial saliva contamination, and mouthwash contamination. The preload and friction coefficient of the abutment screws were recorded. Then, the reverse torque values (RTVs) and settlement were measured after 3.0 × 105 and 6.0 × 105 cycles. The surface wear of the screws was analyzed. Finally, the stress distribution of the abutment screws was calculated by finite element analysis (FEA). The results showed that fluid contamination reduced the friction coefficient, increased the preload, decrease the settlement, improved resistance to screw loosening, and reduced wear on the thread surface. Appropriate antimicrobial lubrication may improve the anti-loosening performance of abutment screws and prevent excessive wear on the threaded surface.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1
Figure 1
Schematic of the preload test apparatus.
Figure 2
Figure 2
Schematic of the test setup and loading apparatus.
Figure 3
Figure 3
Crown, abutment, abutment screw, implant, and fixture: (A) 3D models; (B) structure of the finite element model.
Figure 4
Figure 4
RTVs (T3 and T6) after cyclic loading in the three groups. *Represents P < 0.05 between groups.
Figure 5
Figure 5
Settlement after cyclic loading in the three groups. *Represents P < 0.05 between groups.
Figure 6
Figure 6
Screw surface wear in the NC group. (A) Screw morphology, (B) area shown in (A), (C) EDS at point (a), and (D) EDS at point (b).
Figure 7
Figure 7
Screw surface wear in the SC group. (A) Screw morphology, (B) area shown in (A), (C) EDS at point (a), and (D) EDS at point (b).
Figure 8
Figure 8
Screw surface wear in the MC group. (A) Screw morphology, (B) area shown in (A), (C) EDS at point (a), and (D) EDS at point (b).
Figure 9
Figure 9
Equivalent stress distribution of the abutment screws. (A) NC group, (B) SC group, and (C) MC group.
Figure 10
Figure 10
Frictional stress distribution of the screw taper surface and thread surface. (A,D) NC group, (B,E) SC group, and (C,F) MC group.
See this image and copyright information in PMC

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