Background: Lithium disilicate has proven its clinical success in many clinical situations but no studies supported its use as a cantilever bridge in restoring missing maxillary lateral incisor.
Aim: This study was designed to evaluate the strain induced in lithium disilicate anterior bridges replacing maxillary lateral incisor, as influenced by bridge design; cantilever bridges (CB) versus fixed-fixed bridges (FFB), and direction of loading; vertical(V) and lateral(L).
Materials and methods: 20 heat-pressed monolithic lithium disilicate bridges were constructed , divided according to bridge design into two groups (n=10), 1. CB, and 2. FFB . Main groups were subdivided according to the direction of loading into two subgroups (n=5); V and L.
Wax patterns were duplicated to achieve identical bridges of each group using a custom-made wax injection mold. Ten duplicate epoxy resin dies were produced for each bridge group to hold bridges during testing.
samples were subjected to vertical and lateral loading until complete fracture using universal testing machine. The strain induced in the samples was measured by a KYOWA strain meter. One-way Analysis of Variance (ANOVA) was used to compare between the two bridge designs.
Results:FFBshowed statistically significant higher mean strain value (678.90±34.40) CB (411.80±35.13); while upon lateral loading, the CB showed a significantly higher mean strain value (399.40) than the FFB (262.60).
Conclusion: The strain values induced in lithium disilicate anterior bridges have no catastrophic effect regardless of bridge design, indicating that cantilever bridge design could resist both vertical and lateral loading in a favorable and clinically acceptable mode.