Feldspar Ceramic Strength and The Reinforcing Effect by Adhesive Cementation Under Accelerated Aging

Feldspar ceramics are commonly used in dental restorations due to their esthetic properties and mechanical durability. However, the long-term performance of these materials under clinical conditions remains uncertain. Prior research has shown that ceramic surfaces can be modified to enhance bonding with luting agents, but the impact of these modifications on mechanical strength is not fully understood. Accelerated aging procedures are often used to simulate long-term degradation, yet their effectiveness varies depending on material and coating. This gap motivated the current investigation into how resin luting agents and artificial aging influence feldspar ceramic strength. No prior work had resolved whether adhesive cementation could reinforce ceramic structures under simulated aging. Understanding these interactions is crucial for optimizing dental restoration longevity. The study aimed to clarify whether resin coatings and aging affect ceramic strength and structural reliability. This knowledge could guide material selection and luting protocols in clinical dentistry.

The study aimed to assess how accelerated artificial aging and resin luting agent application affect the mechanical strength of feldspar ceramic. Specifically, the researchers sought to determine whether resin coating improves ceramic strength and whether aging reduces this improvement. The focus was on biaxial flexural strength, characteristic strength, and Weibull modulus as key mechanical indicators. The study also aimed to evaluate structural reliability at two axial positions: ceramic surface and luting agent interface. The motivation stemmed from the need to understand how aging and luting procedures influence ceramic durability in dental applications. The research sought to clarify whether resin coatings offer a consistent mechanical benefit under simulated aging. This could inform clinical practices regarding ceramic restoration bonding and aging resistance. The study's design allowed for direct comparisons between coated and uncoated specimens under aging conditions.

The researchers prepared 120 feldspar ceramic disks, with half acid-etched, silanized, and coated with an experimental resin luting agent. The specimens were divided into four groups: uncoated ceramic, uncoated ceramic with aging, coated ceramic, and coated ceramic with aging. Biaxial flexural testing was performed using a ball-on-ring setup to measure mechanical strength. The study calculated biaxial flexural strength, characteristic strength, and Weibull modulus at two axial positions: ceramic surface and luting agent surface. Statistical analyses were conducted separately for each axial position to assess differences between groups. The aging process simulated long-term degradation using standardized accelerated aging protocols. The experimental resin luting agent was selected to mimic clinical cementation procedures. The study design allowed for a controlled evaluation of how aging and coating interact to influence ceramic strength and reliability.

The uncoated ceramic submitted to accelerated aging showed no significant difference in biaxial flexural strength or characteristic strength compared to the control group. Resin coating increased both strength measures at the ceramic surface but not at the luting agent interface. Accelerated aging increased strength at the ceramic surface for resin-coated specimens and also increased characteristic strength at the luting agent interface. The Weibull modulus remained unchanged across all groups and axial positions. These findings suggest that resin coating enhances ceramic strength regardless of aging. The structural reliability was not affected by the tested variables at either axial position. The absence of significant degradation in uncoated or coated ceramics under aging indicates limited effectiveness of the aging protocol. The results highlight the reinforcing effect of resin luting agents on feldspar ceramic strength.

The authors concluded that resin coating improved the mechanical strength of feldspar ceramic at the ceramic surface. The reinforcing effect was observed regardless of whether the specimens underwent accelerated aging. The aging procedure did not significantly reduce ceramic strength in either uncoated or coated groups. Structural reliability remained unchanged across all tested conditions and axial positions. These findings suggest that resin luting agents provide a consistent mechanical benefit to feldspar ceramics. The study does not propose that aging is an effective method for simulating long-term degradation in these materials. The results support the use of resin coatings to enhance ceramic strength in dental applications. The authors do not suggest that aging protocols should be modified based on this study’s findings.