Mechanical Behavior of Thin Ceramic Laminates on Central Incisors

Area of Science:

• Restorative Dentistry
• Biomaterials Science
• Dental Materials

Background:

• Ceramic laminate veneers are popular for aesthetic anterior restorations.
• Limited understanding exists regarding their clinical performance and the impact of microstructure and processing on longevity.

Purpose of the Study:

• To evaluate the mechanical behavior, fracture load, and failure modes of CAD-CAM processed ceramic laminate veneers.
• To develop a mechanical cycling methodology for assessing the lifetime and failure modes of thin ceramic veneers.

Main Methods:

• Eighteen human maxillary central incisors were prepared minimally for thin ceramic laminates (<0.5 mm).
• Laminate veneers made of lithium disilicate (IPS e.max CAD) and feldspathic porcelain (Vita Mark II) were fabricated via CAD-CAM and cemented with resin cement.
• Mechanical testing included static fracture load and attempts at mechanical cycling.

Main Results:

• Mean fracture load for glass ceramic was 431.8 ± 217.9 N; for porcelain, it was 454.4 ± 72.1 N.
• Failure modes varied: porcelain exhibited more chipping, while lithium disilicate resulted in tooth structure failure.
• Mechanical cycling failed to establish fatigue properties, reaching a maximum of 536,818 cycles.

Conclusions:

• Material type did not significantly impact static fracture load of thin ceramic laminates.
• Distinct failure modes were observed between lithium disilicate and feldspathic porcelain veneers.
• A reliable mechanical cycling methodology for thin ceramic laminates could not be established in this study.