Comparative evaluation of mechanical effects of two designs of immediately placed customized root-analogue zirconia implants in the maxillary and mandibular posterior regions: A finite element analysis.

Background: Customized root-analogue implants (RAIs) with a press-fit design, inserted immediately after tooth extraction, have garnered attention from the researchers and dentists due to their ability to generate frictional force within the tooth extraction socket.

Objectives: The aim of this study was to evaluate the stress distribution and microdisplacement of 2 designs of customized root-analogue zirconia implants in the maxillary and mandibular posterior regions using finite element analysis (FEA).

Material and methods: Four computer-aided design (CAD) models of maxillary and mandibular bone with standard density were constructed based on standard tooth dimensions. The models featured 2 distinct designs, namely fin and bulb designs of RAIs, with 2 models designated for the maxillary first molar and 2 models for the mandibular first molar. All three-dimensional models were converted into finite element models using Altair® HyperMesh® software. Thereafter, loads of 300 N and 100 N were applied in the axial direction to analyze the stress distribution and microdisplacement on peri-implant bone areas using FEA.

Results: The customized root-analogue zirconia implant with the bulb design showed better stress distribution in the surrounding bone when compared to the RAI with the fin design. The micromotion values of the fin design were found to be lower than those of the bulb design, indicating that the former exhibits superior primary stability. The stress distribution of both designs demonstrated reduced stress values in the maxillary posterior region compared to the mandibular posterior region.

Conclusions: The customized root-analogue zirconia implant with added press-fit geometry, i.e, fin or bulb design, has a positive effect on stress distribution and provides enhanced primary stability.