The analysis for the ratio of access-hole with or without marginal staining at the time of T = 12 M showed that the results in group CR (12/16) and in group M4M (12/16) were the same. For this reason, the marginal discrepancy pattern, different in both groups did not influence the aesthetical result. The occlusal contact point (A, B, or C) was compared to the marginal staining rate. Among the access-holes with A or B contact point, 6 out of 16 presented the marginal staining at the time of T = 12 M. For C contact point, 18 out of 40 presented the marginal staining at the time of T = 12 M. No correlation was admitted between the occlusal contact mode and the marginal staining.

An opaque composite resin for the CR group and an opaquer powder for the M4M group might improve the esthetical result and hide the metal frame or the prosthetic screw in the access-hole [36, 37].

Some studies analyzed the effectiveness of a ceramic inlay to restore an access hole [38]. Above the screw, a channel of 3 to 4 mm is needed to achieve this technique and in some clinical situations, there is less than 2 mm. Despite the excellent aesthetical results, with ceramic inlay technique, crown or bridge retrieval is harder and generates an additional cost. The poor clinical result reported with the composite resin filling (control group) might be the fact that a ceramic primer and a bonding agent were not used.