Fracture strengths of chair‑side‑generated veneers cemented with glass fibers
Introduction: CAD/CAM (computer‑aided design and computer‑aided manufacturing) systems have refreshed the idea of chair‑side production of restorations, but the fracture of ceramic veneers remains a problem. Cementation with glass fibers may improve the fracture strengths and affect the failure modes of CAD/CAM‑generated ceramic veneers. Therefore, this study compared the fracture strengths of ceramic veneers produced at chair side and cemented with or without glass fibers with those of composite veneers.
Methodology: Thirty intact mandibular incisors were randomly divided into three groups (n = 10) and treated with CAD/CAM‑fabricated veneers cemented with dual‑cure composite resin luting cement (CRLC; Group 1), CAD/CAM‑fabricated veneers cemented with a glass fiber network (GFN) and dual‑cure CRLC (Group 2), and a direct particulate filler composite veneer constructed utilizing fiber and a restorative composite resin (Group 3). The specimens were tested with a universal testing machine after thermal cycling treatment.
Result: The loads at the start of fracture were the lowest for traditionally fabricated composite veneers and higher for CAD/CAM‑generated. Veneers cemented either without or with the GFN. The failure initiation loads (N) for the veneers were 798.92 for Group 1, 836.27 for Group 2, and 585.93 for Group 3. The predominant failure mode is adhesive failure between the laminates and teeth for Group 1, cohesive failure in the luting layer for Group 2, and cohesive laminate failure for Group 3, which showed chipping and small fractures.
Conclusion: Ceramic material is a reliable alternative for veneer construction at chair side. Fibers at the cementation interface may improve the clinical longevity and provide higher fracture strength values.
Key words: Computer-aided design and computer-aided manufacturing, cementation, fracture strength, glass fiber, laminate veneer