| Objective: Its objective is to compare the microleakage degree of Class V cavities repaired by different resin filling methods,in order to evaluate their effects on the marginal sealing of cervical lesion,and to provide information about the application of various resin filling techniques in Class V cavities.Methods: During this study,32 intact human isolated premolars were collected.All samples had a standard Class V cavities(3mm×3mm×2mm)at the dental neck on the buccal surfaces.Each group of eight was randomly divided into four groups:occlusal-gingival oblique filling group(group A),gingival-occlusal oblique filling group(group B),Segmented incremental filling group(group C),and bulk-filling group(group D),resin filling and polishing according to the unified standard.Following that,2% methylene blue solution was applied to the samples for 24 hours,followed by a2000-cycle temperature cycle.In each group of samples,the sections of the resin filling parts were observed under a stereomicroscope,and the degree of microleakage between the gingival wall and the occlusal wall were measured;scanning electron microscope was used to observe the interface between the filling body and dental tissue.To process and analyze the microleakage grade data of each group,Mann-Whitney U test and Kruskal-Wallis H test were applied.Results:1.Stereomicroscope observation: The gingival and occlusal walls of the four groups show different degrees of marginal microleakage.(1)In the gingival wall group,there was a statistically significant difference between the four groups of filling methods.There were statistically significant differences between group A and group C,D(P <0.05),and there was not a statistically significant difference in group B(P > 0.05).In group B,marginal staining was significantly greater than in groups C and D,and the difference was statistically significant(P < 0.05);there was no statistical difference between C and D(P > 0.05).(2)In the occlusal wall group,a statistically significant difference was not found in the filling methods between the four groups(P>0.05).(3)Among the same groups,there was no statistically significant difference in microleakage of gingival wall and occlusal wall(P>0.05)except group A(P < 0.05).2.Scanning electron microscope(SEM)observation:(1)Gingival wall: There were greater fissures at the interface of group A,no filling material was combined with the tooth,and the interface was debonding.Groups B and C had relatively tight interfaces,with small cracks at individual sites.Group D had a tight interface,with no obvious cracks.(2)Occlusion wall :There are wide cracks at the interface in group A,but resin protrusion is still bonded to the teeth,and the interface has not yet debonded completely.In group B,tiny cracks can be seen at the bonding interface,and the resin protrusion and the tooth form a tight connection.In group C,tiny cracks can be seen on the bonding interface,the surface is smooth and uniform,and the bond is relatively tight.In group D,the bonding interface is continuous and tight,with no cracks.Conclusion:(1)Different resin filling methods will affect the marginal sealing of Class V cavities.In this experiment,marginal microleakage was not avoided through the use of the four filling methods.(2)Compared with the filling methods,the marginal microleakage produced by segmented incremental filling was less than that by gingival-occlusal oblique filling and occlusal oblique-gingival oblique filling.(3)Compared with the resin materials,the edge microleakage generated by the bulk-filling method is less than the two oblique filling methods,and the effect is close to that of the segmented incremental filling. |
PDF Full Text Request