The aim of the present paper was to investigate the effects of soft start polymerisation and the influence of the different adhesive systems on marginal gap formation using a stereological approach. Three adhesive systems [Single Bond (SB), Scotchbond Multi-Purpose (SM) and Clearfil SE Bond (SE)] and two curing techniques (standard cure and soft cure) were studied. For every curing technique, 24 cylindrical class V dentin cavities, 3 mm in diameter and 2 mm thick, were prepared and restorated with 3M Valux Plus composite resin using three different dentin bonding agents. Marginal gap formation was investigated under scanning electron microscope (SEM). On the micrographs, the surface areas of the gaps were measured according to the modified Cavalieri method. Data were analysed by ANOVA and Duncan multi-comparison tests (alpha=0.05). Statistical analysis of variance (ANOVA) presented statistical significance for two factors: curing techniques and adhesives (p < 0.05). Interactions between adhesives and curing technique was not found significantly important (p > 0.05). With the relation averages, The Duncan test was carried out at the 5% level of significance. Soft cure has showed significantly less marginal gap formation in all adhesive systems. Clearfil SE Bond with soft cure has showed significantly less marginal gap formation, whereas Scotchbond MP with standard cure had higher values in all test groups (p < 0.05).