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

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.

Effect of microthreads on removal torque and bone-to-implant contact: an experimental study in miniature pigs

“…Studies pertaining to thread pitch and its effect on crestal bone loss level [10], resistance to vertical load [11], and stress distribution [12] have been reported. These studies demonstrated lower thread pitch to have favorable resistance and stress distribution and less crestal bone loss.…”

Stability of tapered and parallel‐walled dental implants: A systematic review and meta‐analysis

“…8,9 Implant stability, whether primary or secondary, can be influenced by site related factors such as bone quality and quantity as well as the surgical instrumentation and implant macro-and micro-design features. Several reports have shown improved primary implant stability with implants of specific surface modifications, 12 cutting thread configurations, 13,14 and with implants of tapered designs 15 compared with standard implants. Several reports have shown improved primary implant stability with implants of specific surface modifications, 12 cutting thread configurations, 13,14 and with implants of tapered designs 15 compared with standard implants.…”

“…10,11 The role of implant macro and microstructures in improving implant stability has been controversial in the evidence-based literature. Several reports have shown improved primary implant stability with implants of specific surface modifications, 12 cutting thread configurations, 13,14 and with implants of tapered designs 15 compared with standard implants. It has also been demonstrated that implants with tapered design and surface modifications can increase implant stability due to the high bone compression generated during insertion 16 and high contact osteogenesis.…”

Influência da topografia de superfície nanométrica na estabilidade primária de mini-implantes dentários

“…A estabilidade primária também sofre influência direta da área de contato osso/implante, principalmente devido às características associadas ao design (forma, largura, profundidade, inclinação, face e ângulo da hélice) e ao passo de rosca (ângulo e largura). Baseado nisso, o intertravamento mecânico do modelo rosqueado foi superior ao helicoidal, provavelmente devido ao menor passo de rosca, o qual, além de aumentar a área de superfície, melhora a compactação óssea e, consequentemente, o torque de inserção 26,27 . Já no helicoidal, a macrogeometria com apenas duas roscas de passo longo pode ter gerado menor fricção implante/osso, reduzindo a estabilidade inicial no modelo ósseo avaliado 8,28 .…”