Most common cause of failure of class II restoration in children is:
**Core Concept**
The failure of class II restorations in children is often attributed to issues related to the development of the primary and permanent teeth, as well as the behavior and cooperation of the child patient. This includes factors such as pulp vitality, caries progression, and the ability to maintain proper oral hygiene.
**Why the Correct Answer is Right**
The most common cause of failure of class II restorations in children is due to the high prevalence of caries progression. This is often a result of inadequate removal of caries, insufficient use of fluoride, and poor oral hygiene. Additionally, the development of the primary and permanent teeth can lead to changes in the occlusion, which can compromise the restoration's longevity.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not a common cause of failure of class II restorations in children. While it may be a contributing factor, it is not the primary reason for failure.
**Option B:** This option is incorrect because while it may be a factor in the failure of class II restorations, it is not the most common cause.
**Option D:** This option is not a common cause of failure of class II restorations in children. It is more related to the restoration's material properties rather than the underlying causes of failure.
**Clinical Pearl / High-Yield Fact**
It's essential to consider the child's behavior, cooperation, and ability to maintain proper oral hygiene when planning class II restorations. This includes educating the child and their caregivers on the importance of regular fluoride applications and proper brushing techniques.
**Correct Answer: C.**