Which of the following can contribute to post-operative sensitivity in posterior restorations?

Post-operative sensitivity in posterior restorations can be influenced by various factors, and hyper occlusion and over etching are significant contributors.

Hyper occlusion refers to a situation where the restoration is too high, causing excessive pressure on the tooth when it is brought into contact with opposing teeth during biting or chewing. This can lead to discomfort and sensitivity as the tooth is stressed beyond its normal capacity.

On the other hand, over etching can result in excessive removal of the dentin layer, which may diminish the integrity of the tooth structure and affect the bonding strength of the restoration. This, in turn, can create pathways for irritation and sensitivity. When the inner dentin is overly exposed or compromised, it can lead to heightened sensitivity to thermal stimuli and pressure.

While inadequate bonding, improper cleaning, and long exposure to air can also potentially contribute to post-operative sensitivity, they do not encompass the mechanical and chemical aspects as directly related to immediate sensitivity as hyper occlusion and over etching do. Understanding these two factors is crucial in preventing sensitivity issues in posterior restorations.