Microleakage in Class V Restorations in Vitro

OBJECTIVE: In-vitro study assessed the marginal microleakage on Class V cavities .

METHODS: Sixty molars divided into four groups (N=15). Preparations on the buccal/lingual surface with a dimension of 4 mm (occlusogingival), 3 mm (mesiodistal) and 1.5 mm (depth). The occlusal/gingival margins were 2 mm above/below the cemento-enamel junction .

 Group 1– resin-modified glass ionomer primer (Vitrebond^TM – 3M ESPE), acid etch    (Adper Single Bond Plus- 3M ESPE)

 Group 2 – acid etch, flowable Tetric Flow (Ivolar Vivadent),

 Group 3 – resin-modified glass ionomer primer (Vitrebond Plus), acid etch

 Group 4 – acid  etching, no liner

Groups were restored with Z 250 (3M ESPE) composite and finished with Softflex XT (3m ESPE). Specimens were thermocycled 1000 cycles between 5-55°C (30s dwell time). They were stored in basic fuchsine 0,5% at 37° C for 24 hrs, sectioned along a bucco-lingual plane through the middle. Scores were accessed: 0 – no penetration, 1 – penetration short of the dentinoenamel junction, 2- penetration short of the axial wall, 3 - penetration to and along the axial wall. RESULTS: Kruskal-Wallis revealed statistical difference for all groups, cervical (p=0.000) and occlusal (p= 0.000) interfaces. The cervical interfaces Mann-Whitney U displayed significant differences between Groups 4 and 2 (p=0.00). No significant difference among Groups 1, 3 and 4 (p=0.775, p= 0.838, p = 0,925). The occlusal interfaces, significant differences among Groups 4 and 2 (p<0.000). No significant differences among the Groups 1, 3 and 4 (p=0.061, p= 0.217).

A comparison at cervical and occlusal in each group, ANOVA tests, revealed significant differences among all groups (p< 0.0001).

 CONCLUSIONS:

At the cervical interfaces, a flowable prior to composite restoration significantly increases microleakage. At the occlusal interfaces the use of resin-modified glass ionomer primer or no liner can help to reduce microleakage.  Microleakage at the cervical is greater than at the occlusal interfaces.