مقاومة الانكسار لجسور الأطواق الزيركونية : دراسة مخبرية استطلاعية

الملخص EN

Background and Aim of study : Metal sleeve bridges were previously designed with partial preparations for the abutments where they leave the occlusal surface without preparation to maintain the occlusion and to maintain as much as possible the dental tissue and clinical length of the abutments, which increases the stability of these bridges, and due to the increased cosmetic requirements the idea originated of making these bridges from zirconia.

This study is interested in assessing these bridges' laboratory fracture resistance.

Materials and Methods : The test framework was designed as 3- unit bridge with two abutment teeth premolar and second molar of the mandible A survey of the gypsum example was conducted before preparation and after preparation by the CAD-CAM.

Four bridges were milled and then the fracture resistance was studied at the Industrial Research Center by applying the head of the test device vertically to each bridge in a specific area and then the force needed to cause breakage in the bridges was recorded in Newton.

Results : The mean of fracture resistance was 1792 N.

The lowest value was seen at the mesial wall of premolar, while the highest at the connector between the premolar and the pontic and all values were within 1541-2152 N.

Conclusions : Within the limitations of this in vitro study, it is found that sleeve zirconia bridges can be resistant to chewing forces if used clinically, compared to the average of physiological occlusal force which is about a quarter or half of the resistance of these bridges.