The objectives of this study are to characterize the clinical performance and wear mechanisms of all-ceramic posterior crowns. The wear rate of all-ceramic crowns and opposing enamel in selected patients will be quantified. The relationship of each subject's maximum clenching force and wear rate will also be analyzed.

High strength ceramics have been used in dentistry for constructing fixed partial denture. Their advantages are their acceptable fracture resistance, excellent biocompatibility, moderate opacity, etc. Because the increase in demand for more esthetic restoration, various ceramic materials have been used as a core material for several all-ceramic systems. Their properties have been investigated extensively in many in vitro studies. Currently, there are not much results regarding clinical performance and wear mechanism of ceramic-based prosthesis and more information are required for future research.

Inclusion Criteria:

• Occlusion: At least 20 remaining teeth for each patient, and at least one posterior endodontically treated tooth with natural opposing teeth
• Bruxism: No evidence based on an intraoral examination
• Dental history: No evidence of either moderate or severe periodontal disease
• Medical history: Good to excellent general health

Exclusion Criteria:

• Periodontal status: Pocket depth greater than 4 mm

• Occlusion:

  • Evidence of bruxism or excessive biting or clenching force
  • Abutment tooth that opposes a removable partial denture
  • Abutment tooth for fixed partial dentures
  • Gingival recession of an abutment tooth more than 1 mm from the cementoenamel junction
  • Tooth with first or second degree of tooth mobility
  • Tooth with extensive carious lesions