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Influence of thread pitch, helix angle, and compactness on micromotion of immediately loaded implants in three types of bone quality: a three-dimensional finite element analysis.

Ma P, Xiong W, Tan B, Geng W, Liu J, Li W, Li D - Biomed Res Int (2014)

Bottom Line: We found that vertical relative displacement was affected by thread pitch, helix angle, and compactness.Under vertical loading, displacement was positively correlated with thread pitch and helix angle but negatively with compactness.Bone type amplifies the influence of thread pattern on displacement.

View Article: PubMed Central - PubMed

Affiliation: Department of Oral Implantology, Beijing Stomatological Hospital of Capital Medical University, Beijing 100050, China ; Department of Oral Implantology, School of Stomatology, State Key Laboratory of Military Stomatology, The Fourth Military Medical University, Xi'an, Shanxi 710032, China.

ABSTRACT
This study investigated the influence of thread pitch, helix angle, and compactness on micromotion in immediately loaded implants in bone of varying density (D2, D3, and D4). Five models of the three-dimensional finite element (0.8 mm pitch, 1.6 mm pitch, 2.4 mm pitch, double-threaded, and triple-threaded implants) in three types of bone were created using Pro/E, Hypermesh, and ABAQUS software. The study had three groups: Group 1, different pitches (Pitch Group); Group 2, same compactness but different helix angles (Angle Group); and Group 3, same helix angle but different compactness (Compact Group). Implant micromotion was assessed as the comprehensive relative displacement. We found that vertical relative displacement was affected by thread pitch, helix angle, and compactness. Under vertical loading, displacement was positively correlated with thread pitch and helix angle but negatively with compactness. Under horizontal loading in D2, the influence of pitch, helix angle, and compactness on implant stability was limited; however, in D3 and D4, the influence of pitch, helix angle, and compactness on implant stability is increased. The additional evidence was provided that trabecular bone density has less effect on implant micromotion than cortical bone thickness. Bone type amplifies the influence of thread pattern on displacement.

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Five different configurations of implants with abutment.
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fig1: Five different configurations of implants with abutment.

Mentions: The 3D models of a mandibular bone block and a screw-shaped dental implant with a healing abutment were constructed using computer assisted designing (CAD) system (PRO/E) on a personal computer. To study the thread helix angel and the compactness of the single-threaded, double-threaded, and triple-threaded implants, five different V-shaped threaded implants were designed: single-threaded implants with pitches of 0.8 mm, 1.6 mm, and 2.4 mm; a double-threaded implant with a thread pitch of 1.6 mm and thread spacing of 0.8 mm; and a triple-threaded implant with a thread pitch of 2.4 mm and thread spacing of 0.8 mm (Figure 1). For analysis, we compared these designs as three groups: Group 1, or the Pitch Group, had different pitches, including single-threaded implants with pitches of 0.8 mm, 1.6 mm, and 2.4 mm; Group 2, or the Angle Group, had the same thread compactness but different helix angles, including double-threaded, triple-threaded implants, and single-threaded implant with 0.8 mm pitch; and Group 3, or the Compactness Group, had the same helix angle and different thread compactness, including double-threaded and single-threaded implants with 1.6 mm pitch and triple-threaded and single-threaded implants with 2.4 mm pitch (please refer to Table 1). All implants were designed with a 3.7 mm tip diameter, 10.0 mm threaded length, and 0.3 mm collar height (helix angle, α = β = 60°).


Influence of thread pitch, helix angle, and compactness on micromotion of immediately loaded implants in three types of bone quality: a three-dimensional finite element analysis.

Ma P, Xiong W, Tan B, Geng W, Liu J, Li W, Li D - Biomed Res Int (2014)

Five different configurations of implants with abutment.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4109075&req=5

fig1: Five different configurations of implants with abutment.
Mentions: The 3D models of a mandibular bone block and a screw-shaped dental implant with a healing abutment were constructed using computer assisted designing (CAD) system (PRO/E) on a personal computer. To study the thread helix angel and the compactness of the single-threaded, double-threaded, and triple-threaded implants, five different V-shaped threaded implants were designed: single-threaded implants with pitches of 0.8 mm, 1.6 mm, and 2.4 mm; a double-threaded implant with a thread pitch of 1.6 mm and thread spacing of 0.8 mm; and a triple-threaded implant with a thread pitch of 2.4 mm and thread spacing of 0.8 mm (Figure 1). For analysis, we compared these designs as three groups: Group 1, or the Pitch Group, had different pitches, including single-threaded implants with pitches of 0.8 mm, 1.6 mm, and 2.4 mm; Group 2, or the Angle Group, had the same thread compactness but different helix angles, including double-threaded, triple-threaded implants, and single-threaded implant with 0.8 mm pitch; and Group 3, or the Compactness Group, had the same helix angle and different thread compactness, including double-threaded and single-threaded implants with 1.6 mm pitch and triple-threaded and single-threaded implants with 2.4 mm pitch (please refer to Table 1). All implants were designed with a 3.7 mm tip diameter, 10.0 mm threaded length, and 0.3 mm collar height (helix angle, α = β = 60°).

Bottom Line: We found that vertical relative displacement was affected by thread pitch, helix angle, and compactness.Under vertical loading, displacement was positively correlated with thread pitch and helix angle but negatively with compactness.Bone type amplifies the influence of thread pattern on displacement.

View Article: PubMed Central - PubMed

Affiliation: Department of Oral Implantology, Beijing Stomatological Hospital of Capital Medical University, Beijing 100050, China ; Department of Oral Implantology, School of Stomatology, State Key Laboratory of Military Stomatology, The Fourth Military Medical University, Xi'an, Shanxi 710032, China.

ABSTRACT
This study investigated the influence of thread pitch, helix angle, and compactness on micromotion in immediately loaded implants in bone of varying density (D2, D3, and D4). Five models of the three-dimensional finite element (0.8 mm pitch, 1.6 mm pitch, 2.4 mm pitch, double-threaded, and triple-threaded implants) in three types of bone were created using Pro/E, Hypermesh, and ABAQUS software. The study had three groups: Group 1, different pitches (Pitch Group); Group 2, same compactness but different helix angles (Angle Group); and Group 3, same helix angle but different compactness (Compact Group). Implant micromotion was assessed as the comprehensive relative displacement. We found that vertical relative displacement was affected by thread pitch, helix angle, and compactness. Under vertical loading, displacement was positively correlated with thread pitch and helix angle but negatively with compactness. Under horizontal loading in D2, the influence of pitch, helix angle, and compactness on implant stability was limited; however, in D3 and D4, the influence of pitch, helix angle, and compactness on implant stability is increased. The additional evidence was provided that trabecular bone density has less effect on implant micromotion than cortical bone thickness. Bone type amplifies the influence of thread pattern on displacement.

Show MeSH