Effect of insertion factors on dental implant insertion torque/energy-experimental results

• Published in: Journal of the mechanical behavior of biomedical materials 2020-12, Vol.112, p.103995-103995, Article 103995
• Main Authors: Yang, Baixuan, Irastorza-Landa, Ainara, Heuberger, Peter, Ploeg, Heidi-Lynn
• Format: Article
• Language: English
• Subjects: Anchorage; Bone Density; Bone Screws; Dental implant; Dental Implants; Dental Prosthesis Design; Dental Stress Analysis; Insertion energy; Insertion torque; Mechanical Phenomena; Torque
• ISSN: 1751-6161; 1878-0180
• DOI: 10.1016/j.jmbbm.2020.103995

Anchorage of dental implants is quantified with a mechanical engagement to insertion, for example maximum insertion torque (MIT) and insertion energy (IE). Good anchorage of dental implants highly correlates to positive clinical outcomes. However, it is still unclear how bone density, drill protocol, surface finish and cutting flute affect anchorage. In this study, effects of the insertion factors on both MIT and IE were investigated using a full-factorial experiment at two levels: bone surrogate density (0.32 g/cm3 versus 0.48 g/cm3), drill protocol (Ø2.4/2.8 versus Ø2.8/3.2 mm), implant surface finish (machined versus anodized surface) and cutting flute (with versus without). Osteotomies were prepared on rigid polyurethane foam blocks with dimensions of 40 × 40 × 8 mm. Screw shaped dental implants with variable tapered body were consecutively inserted into and removed from the polyurethane foam blocks three times under constant axial displacement and rotational speed. Axial force and torque were recorded synchronously. Insertion energy was calculated from the area under the torque-displacement curve. In this study, we found the main insertion mechanics were thread forming for the first insertion. For the second and third insertions, the main mechanics shifted to thread tightening. Maximum insertion torque (MIT) responded differently to the four insertion factors in comparison to IE. Bone surrogate density, drill protocol and surface finish had the largest main effects for first MIT. For the first IE, drill protocol, surface finish and cutting flute were significant contributors. These results suggest that MIT and IE are influenced by different mechanics: the first MIT and the first IE were sensitive to thread tighten and forming, respectively. Together MIT and IE provide a complete assessment of dental implant anchorage. [Display omitted] •Bone density, drill protocol and surface influenced dental implant insertion torque.•These factors directly relate to a stress level or friction force in the bone.•Drill protocol, surface and cutting flute contributed to first insertion energy.•Insertion energy was influenced by the stress distribution.•Together, torque and energy give a more complete understanding of implant anchorage.