The Influence of Cement Systems on the Outcome of Tooth Supported Zirconia Crowns in the Posterior Region: a Randomized ,Multicenter, and Practice-based Clinical Trial

Tooth damage has significant impact on a person's quality of life and damaged teeth should be treated to restore lost functions and prevent further damage. Loss of tooth substance can be restored by a direct (filling) or indirect restoration (artificial crown). These interventions differ in some operative aspects but share key challenges, particularly in achieving optimal adhesion to tooth substance to secure predictable retention and the integrity of the marginal seal.

Failure of the adhesive interface is a major determinant of restoration longevity and may manifest across patient-centered, biological, and technical outcomes.

Marginal degradation may result in discoloration, representing an early clinical indicator of interface breakdown that negatively affects patient satisfaction and may lead to a need for retreatment. Progressive marginal leakage facilitates bacterial access, increasing the risk of biological complications such as secondary caries and pulpal involvement.

Loss of retention represents a major technical complication, often requiring replacement of the restoration and contributing to cumulative loss of tooth structure over time.

Despite advances in restorative materials and adhesive systems, clinical outcomes remain variable, and the relative contribution of material properties, procedural complexity, and biological factors to long-term failure is not fully understood. In particular, the role of technique sensitivity and procedural complexity as independent determinants of restoration survival remains insufficiently characterized. Improved understanding of these interacting factors will enable more precise selection of restorative materials and cementation strategies.