Does enamel matrix derivative application provide additional clinical benefits in the treatment of maxillary Miller class I and II gingival recession? A systematic review and meta-analysis

Objective: This review aimed to evaluate the effects of enamel matrix derivative (EMD) in association with coronally advanced flap (CAF) or CAF + connective tissue graft (CTG) when compared with CAF alone or CAF + CTG for the treatment of gingival recessions (GR) in maxillary teeth. Methods: Five databases and gray literature were searched up to April 2020, to find randomized clinical trials comparing the clinical effects of CAF + EMD versus CAF alone (first group) or CAF + CTG + EMD versus CAF + CTG (second group) in the treatment of Miller class I and II or Cairo type I gingival recessions (GR). Random effects model of mean differences was used to determine the GR reduction, gain in keratinized tissue width (KTW), and gain in clinical attachment level (CAL). The trial sequential analysis (TSA) was implemented to determine the optimal information size (OIS) and imprecision using the GRADE approach. Bayes factors were calculated as complementary statistical evidence of p value. Results: From 1349 titles identified, 9 trials representing 336 GR were included. The meta-analysis showed a statistically significant difference for GR reduction and CAL gain in favor CAF + EMD (p ≤ 0.05). The additional effect of EMD showed a statistically significant difference in GR reduction in favor CAF + CTG + EMD (p ≤ 0.05). The differences in KTW gain proved to be not statistically significant in both comparison groups. The OIS were not met among meta-analyses. Evidence certainty according the GRADE approach proved to be moderate for GR reduction and gain in CAL, but very low for gain in KTW. Conclusion: The adjunctive application of EMD in the treatment of GR in maxillary teeth either with CAF or CTG provided moderate certainty evidence in favor of their use for reduction in GR and gain in CAL at 6 and 12 months. However, their effect on the increase in keratinized tissue band height showed very low evidence certainty for its use. Clinical relevance: To know if EMD could improve the results for root coverage.