Inclusion Criteria:

• * at least 18 years of age
• * at least one carious lesion, defective restoration, or fractured portion of the tooth to be restored on a maxillary or mandibular premolar or molar tooth - Each lesion, fracture, or defective restoration should exhibit sufficient size or loss of tooth structure requiring a full crown restoration.
• * tooth should have at least one opposing tooth in occlusion and one adjacent tooth with an intact proximal contact
• * No more than ten teeth that are endodontically treated may be included in the study, equally divided between the two groups of crowns. All remaining teeth in the study will test vital and be asymptomatic at the beginning of treatment.
• * No more than two restorations will be placed per patient

Exclusion Criteria:

• * Sensitive teeth
• * Teeth with a history of direct or indirect pulp capping procedures
• * Patients with significant untreated dental disease to include periodontitis and/or rampant caries
• * Women who self-report that they are possibly pregnant, pregnant, or lactating, as elective dental treatment is not indicated at these times
• * Patients with a self-reported history of allergies to the materials to be used in the study including composite resin cements or zirconia restorative materials
• * Patients unable to return for the recall appointments