Stress Distributions Created by Short and Regular Implants Placed in the Anterior Maxilla at Different Angles: A Finite Element Analysis

Although short implants are seen as alternative treatments that require

additional surgical techniques in posterior region, they can be applied

to anterior maxilla and various studies are required on this subject.

The purpose of this study was to examine and compare the peak von Mises

stress distributions in the crown, implant and abutment by using finite

element analysis (FEA). Besides, a comparison of the implant-abutment

connection types in the short implant with the FEA method was

established. A short implant (4 × 5 mm) with a taper-lock connection and

a regular implant (4 × 9 mm) with a screw connection were used in

maxillary central incisor tooth area. Three different titanium abutments

with 0?, 15? and 25? angles were used for abutments. In addition, in

order to determine whether the stress change in short implants is due to

the length of the implant-abutment connection, a screw was designed for

a short implant and it was also evaluated in the same three angles. A

total of three groups and nine models were generated. 114.6N load was

applied to the cingulum area of the crown at an angle of 135? to the

long axis of the crowns. A torque load of 25 Ncm was applied to the

regular and short implant screw. Von Mises stress distributions of

implants, abutments and crowns were evaluated by using FEA. Increased

angle in implants increased von Mises stress values of implant, abutment

and crown. Screw connection was found higher at all angles in short

implants. Close values were found at different angles in taper-lock

short implant crowns. The length and the angle in the bone of implant

with the type of implant-abutment connection results in the accumulated

stress values. Clinical Implications Taper implant-abutment connection

system was found to be more promising in terms of stress accumulation in

crowns. Although the amount of stress on the abutment increased due to

the length of the implant in short implants, taper implant-abutment

connection system slightly reduced related to this increase.