The taper of preparation is disproportional to which factor?

The taper of a dental preparation relates primarily to how well the restoration can be retained in the mouth. Increasing the taper (the angle at which the walls of the preparation converge) can reduce the retention of the restorative material because it creates less surface area for bonding and can lead to a tendency for the restoration to dislodge. Therefore, retention is significantly affected by the taper of the preparation.

While the other factors—periodontal health, esthetics, and material strength—may influence the overall treatment plan or selection of restorative material, they are not fundamentally tied to the angle of taper in the same way retention is. Periodontal health does play a role in determining the overall treatment approach, and material strength will guide the choice of material used, but neither directly correlates with the taper's impact on retention capabilities. Esthetics can indeed be influenced by preparation design, but it is a secondary consideration compared to the primary goal of ensuring sufficient retention through appropriate taper. Thus, tapering is disproportional to retention, establishing this answer as the most relevant to the question.