Selection of Blade Implants from the Point of Stress Analysis on Endosseous Implants

Abstract

Basically there are two types of blade implants for endoosseous implantation,single-and double-headed, and either is chosen depending on the situation.
On the presumption that this difference in the number of heads has an impact on the distribution of stress on the alveolar, we conducted stress analysis by photoelasticity examination, which is the most popular,on implants with single-and double-heads where they are planted horizontally and also where the necks are bent 20°. The photoelastic resin and hardener employed for the experiment are Epicoat 828 and triethylene-tetra-amine (TTA) respectively in the ratio of 100:8. The process of hardening was done at 50℃, and the mixture was cooled down slowly, taking four hours.
In the experiment, single-and double-headed blades were planted in the mixture with the heads horizontal and the necks being bent 20° in the direction of the mesial point, and a vertical weight of 0.20, and 40 kg was given to the blades.From the point of view of practitioners,we report the following findings obtained through this stress analysis.
From time to time we observe cases with several year histories after implantation in which the necks of metal blades are broken or cracked. Most of them are cases of single-head type, and the damage is often found near the botton of the implants especially when their necks are bent in the direction of the medial point.It can be said that stress is more likely to be concentrated causing fatigue of the metal of single-hended blades.