Which procedure includes an over-etching consequence that might lead to post-operative issues?

The option related to the Class II composite procedure is correct because over-etching in this context can lead to complications such as increased sensitivity, diminished bond strength, and potential pulpal irritation post-operatively. Over-etching occurs when an excessive amount of enamel or dentin is treated with an etching solution. This can result in the removal of too much mineral content, leading to an overly porous structure that can adversely affect the adhesive properties of the restorative material.

When a Class II composite restoration is performed, proper etching is crucial for ensuring a strong bond between the composite material and tooth structure. If the enamel or dentin is over-etched, it may not only compromise the restoration's integrity but also lead to patient discomfort and sensitivity due to the exposure of dentinal tubules. This sensitivity can persist after the procedure, causing significant discomfort for the patient.

In contrast, the other procedures listed do not typically involve etching to the same extent or in a manner that would lead to such pronounced post-operative consequences. Class I amalgam restorations do not require etching, while post-operative cleaning and teeth whitening procedures don't involve the type of bonding that is critical in composite placements.