Which factor could affect bond strength and potentially cause a restoration to fail?

Which factor could affect bond strength and potentially cause a restoration to fail?

• A. Deeper cavity preparation
• B. Extra occlusal force
• C. Use of glass ionomer cement
• D. Presence of calculus on tooth

Answer: (A)

Bond strength depends on the quality and amount of tooth surface available for adhesive infiltration and the integrity of the bonding interface. When a cavity is prepared more deeply, more dentin near the pulp is exposed, and that dentin is typically wetter, more permeable, and has larger open tubules. This makes it harder for adhesive agents to properly infiltrate and form strong resin tags, and it also reduces the contribution of enamel bonding since less enamel remains to provide a durable, high-strength bond. The result is weaker adhesion and a greater chance of marginal leakage, debonding, or restoration failure under functional stresses. Extra occlusal force can lead to fracture of the restoration or tooth but doesn’t inherently weaken the bond at the interface in the same systematic way. Calculus on the tooth would prevent proper bonding until cleaned, but once the surface is cleaned, the bond can often be achieved. Glass ionomer cement has its own bonding properties, and while it may behave differently from resin-based systems, the depth-related changes in bonding surface most directly reduce bond strength and raise failure risk.

Bond strength depends on the quality and amount of tooth surface available for adhesive infiltration and the integrity of the bonding interface. When a cavity is prepared more deeply, more dentin near the pulp is exposed, and that dentin is typically wetter, more permeable, and has larger open tubules. This makes it harder for adhesive agents to properly infiltrate and form strong resin tags, and it also reduces the contribution of enamel bonding since less enamel remains to provide a durable, high-strength bond. The result is weaker adhesion and a greater chance of marginal leakage, debonding, or restoration failure under functional stresses.

Extra occlusal force can lead to fracture of the restoration or tooth but doesn’t inherently weaken the bond at the interface in the same systematic way. Calculus on the tooth would prevent proper bonding until cleaned, but once the surface is cleaned, the bond can often be achieved. Glass ionomer cement has its own bonding properties, and while it may behave differently from resin-based systems, the depth-related changes in bonding surface most directly reduce bond strength and raise failure risk.