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The Effects of Different Miniscrew Thread Designs and Force Directions on Stress Distribution by 3-dimensional Finite Element Analysis.

Fattahi H, Ajami S, Nabavizadeh Rafsanjani A - J Dent (Shiraz) (2015)

Bottom Line: Many attempts have been made to reduce the size, to improve the design, and to increase the stability of miniscrew.The purpose of this study was to determine the effects of different thread shapes and force directions of orthodontic miniscrew on stress distribution in the supporting bone structure.Stress distribution was not significantly different among different thread shapes.

View Article: PubMed Central - PubMed

Affiliation: Orthodontic Research Center, Dept. of Orthodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.

ABSTRACT

Statement of the problem: The use of miniscrew as an absolute anchorage device in clinical orthodontics is growing increasingly. Many attempts have been made to reduce the size, to improve the design, and to increase the stability of miniscrew.

Purpose: The purpose of this study was to determine the effects of different thread shapes and force directions of orthodontic miniscrew on stress distribution in the supporting bone structure.

Materials and method: A three-dimensional finite element analysis was used. A 200-cN force in three angles (0°, 45°, and 90°) was applied on the head of the miniscrew. The stress distribution between twelve thread shapes was investigated as categorized in four main groups; buttress, reverse buttress, square, and V-shape.

Results: Stress distribution was not significantly different among different thread shapes. The maximum amount of bone stress at force angles 0°, 45°, and 90° were 38.90, 30.57 and 6.62 MPa, respectively. Analyzing the von Mises stress values showed that in all models, the maximum stress was concentrated on the lowest diameter of the shank, especially the part that was in the soft tissue and cervical cortical bone regions.

Conclusion: There was no relation between thread shapes and von Mises stress distribution in the bone; however, different force angles could affect the von Mises stress in the bone and miniscrew.

No MeSH data available.


Related in: MedlinePlus

Deformation patterns in a miniscrew model under horizontal loading
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Figure 5: Deformation patterns in a miniscrew model under horizontal loading

Mentions: The maximum deformation in all groups was at the head of the miniscrew, whereas to the tip of the miniscrew, this value was reduced. (Figure 5) With the 0° force of angle loading, the maximum value was for square 1(S-1) thread shape (0.0116 mm) and the minimum was for V-shape 2 (V-2) thread shape (0.0154 mm). At the 45° force angle, the result showed the range was between 0.0070 mm and 0.0109 mm. The largest value was for square 1(S-1) thread shape and the minimum was for V- shape 1(V-1) thread shape (Table 5).


The Effects of Different Miniscrew Thread Designs and Force Directions on Stress Distribution by 3-dimensional Finite Element Analysis.

Fattahi H, Ajami S, Nabavizadeh Rafsanjani A - J Dent (Shiraz) (2015)

Deformation patterns in a miniscrew model under horizontal loading
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664032&req=5

Figure 5: Deformation patterns in a miniscrew model under horizontal loading
Mentions: The maximum deformation in all groups was at the head of the miniscrew, whereas to the tip of the miniscrew, this value was reduced. (Figure 5) With the 0° force of angle loading, the maximum value was for square 1(S-1) thread shape (0.0116 mm) and the minimum was for V-shape 2 (V-2) thread shape (0.0154 mm). At the 45° force angle, the result showed the range was between 0.0070 mm and 0.0109 mm. The largest value was for square 1(S-1) thread shape and the minimum was for V- shape 1(V-1) thread shape (Table 5).

Bottom Line: Many attempts have been made to reduce the size, to improve the design, and to increase the stability of miniscrew.The purpose of this study was to determine the effects of different thread shapes and force directions of orthodontic miniscrew on stress distribution in the supporting bone structure.Stress distribution was not significantly different among different thread shapes.

View Article: PubMed Central - PubMed

Affiliation: Orthodontic Research Center, Dept. of Orthodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.

ABSTRACT

Statement of the problem: The use of miniscrew as an absolute anchorage device in clinical orthodontics is growing increasingly. Many attempts have been made to reduce the size, to improve the design, and to increase the stability of miniscrew.

Purpose: The purpose of this study was to determine the effects of different thread shapes and force directions of orthodontic miniscrew on stress distribution in the supporting bone structure.

Materials and method: A three-dimensional finite element analysis was used. A 200-cN force in three angles (0°, 45°, and 90°) was applied on the head of the miniscrew. The stress distribution between twelve thread shapes was investigated as categorized in four main groups; buttress, reverse buttress, square, and V-shape.

Results: Stress distribution was not significantly different among different thread shapes. The maximum amount of bone stress at force angles 0°, 45°, and 90° were 38.90, 30.57 and 6.62 MPa, respectively. Analyzing the von Mises stress values showed that in all models, the maximum stress was concentrated on the lowest diameter of the shank, especially the part that was in the soft tissue and cervical cortical bone regions.

Conclusion: There was no relation between thread shapes and von Mises stress distribution in the bone; however, different force angles could affect the von Mises stress in the bone and miniscrew.

No MeSH data available.


Related in: MedlinePlus