Comparison of stress distribution around splinted and nonsplinted implants with different crown height space in posterior mandible: A finite element analysis study.

Purpose: The purpose of this finite element analysis (FEA) study was to analyze the stress distribution on prosthetic components of splinted and nonsplinted prostheses, bone, and implants with different crown height space (CHS).

Materials and methods: Mandibular posterior segment was modeled with no resorption at the second premolar site and various amounts of resorption (0, 3, 6, and 9 mm) at the first molar site. Two adjacent implants (Straumann bone level implants, 4.1 mm×8 mm) were placed; at the second premolar site, the crown height was 8 mm and at the first molar site, the crown height varied (8, 11, 14, and 17 mm), depending on the amount of resorption. Both splinted and nonsplinted crowns were designed. Vertical and oblique loads of 400 N were applied to the crowns. von Mises stress was used to evaluate the stress distribution in the implant complex and maximum principal stress was used to evaluate the stress in the bone.

Results: When oblique forces were applied, the highest von Mises stresses were observed for nonsplinted crowns in the 17 mm CHS group. The maximum principal and minimum principal stresses observed in bone under oblique loading increased with increased CHS for nonsplinted restorations.

Conclusions: Crown height affected the amount of stress in bone and implant components. When the crown height difference between two adjacent implants increases, splinting may be crucial.