Evaluation of marginal quality at 6 , 12 , 24 , 36 and 48 months was performed and described as good marginal adaption or as poor quality defined as Inadequacy A ( IA ) : overhanging resin or change of color ; Inadequacy B ( IB ) : the presence of a gap at the enamel-composite interface that retained the probe tip ; or Inadequacy C ( IC ) presence of gap at the enamel-composite interface with explorer tip penetration of more than 1 mm .