Deep margin elevation versus crown lengthening: biologic width revisited

This article revisits the concept of biologic width, in particular its clinical consequences for treatment options and decisions in light of modern dentistry approaches such as biomimetics and minimally invasive procedures. In the past, due to the need to respect biologic width, clinicians were used to removing periodontal tissue around deep cavities, bone, and gum so that the limits of restorations were placed far away from the epithelium and connective attachments, in order to prevent tissue loss, root exposure, opening of the proximal area (leading to black holes), and poor esthetics. Furthermore, no material was placed subgingivally in case it led to periodontal inflammation and attachment loss. Today, with the more conservative approach to restorative dentistry, former subtractive procedures are being replaced with additive ones. In view of this, one could propose deep margin elevation (DME) instead of crown lengthening as a change of paradigm for deep cavities. The intention of this study was to overview the literature in search of scientific evidence regarding the consequences of DME with different materials, particularly on the surrounding periodontium, from a clinical and histologic point of view. A novel approach is to extrapolate results obtained during root coverage procedures on restored roots to hypothesize the nature of the healing of proximal attachment tissue on a proper bonded material during a DME. Three clinical cases presented here illustrate these procedures. The hypothesis of this study was that even though crown lengthening is a valuable procedure, its indications should decrease in time, given that DME, despite being a very demanding procedure, seems to be well tolerated by the surrounding periodontium, clinically and histologically.