Comparative analysis of stress in a new proposal of dental implants

The purpose of this study was to compare, through photoelastic analysis, the stress distribution around conventional and modified external hexagon (EH) and morse taper (MT) dental implant connections. Four photoelastic models were prepared (n = 1): Model 1 - conventional EH cylindrical implant (empty set 4.0 mm x 11 mm - Neodent (R)), Model 2 - modified EH cylindrical implant, Model 3 - conventional MT Conical implant (empty set 43 mm x 10 mm Neodent (R)) and Model 4 - modified MT conical implant. 100 and 150 N axial and oblique loads (30 degrees tilt) were applied in the devices coupled to the implants. A plane transmission polariscope was used in the analysis of fringes and each position of interest was recorded by a digital camera. The Tardy method was used to quantify the fringe order (n), that calculates the maximum shear stress (T) value in each selected point. The results showed lower stress concentration in the modified cylindrical implant (EH) compared to the conventional model, with application of 150 N axial and 100 N oblique loads. Lower stress was observed for the modified conical (MT) implant with the application of 100 and 150 N oblique loads, which was not observed for the conventional implant model. The comparative analysis of the models showed that the new design proposal generates good stress distribution, especially in the cervical third, suggesting the preservation of bone tissue in the bone crest region. (C) 2017 Elsevier B.V. All rights reserved.