The effect of contact area morphology on operative dental procedures

Measurements of the contact and embrasure areas of adjacent extracted teeth set in plaster blocks were made before groups of dentists undertook preparations on them. The prepared and adjacent teeth were examined and the findings related back to these measurements. Damage to the adjacent teeth was a common finding with both mesial-occlusal-distal (MOD) and complete crown preparations. There was some evidence that easier access to the contact area reduced the frequency of damage to teeth adjacent to MOD preparations. The taper of complete crown preparations did not conform to commonly recommended designs. This investigation highlights the need for greater consideration of approximal tooth surfaces when undertaking preparations and questions the practicality of achieving traditional features of complete crown preparation design. In teaching, greater emphasis should be placed on clinical reality rather than on theoretical, but unachievable ideals.