Dentin Protection of Different Desensitizing Varnishes During Stress Simulation: An In Vitro Study

The aim of this study was to investigate dentin protection of different desensitizing varnishes (light- and self-curing) during acid action/abrasion stress and thermocyclic loading in vitro.

Dentin discs of 2 mm thickness were cut from 120 human molars, embedded, and polished. Specimens were randomized into five groups (n=24): A, negative control; B, Gluma Desensitizer; C, Cervitec plus (self-curing); D, Seal&Protect; and E, Admira Protect (light-curing). In groups B-E, varnish was applied on two-thirds of the dentin surface, and one-third acted as internal control. Stress cycle (2 cycles/day) for specimens were as follows: 1, acid action (pH: 2.9: five minutes); 2, remineralization (synthetic saliva: 60 minutes); 3, brushing (100 strokes); 4, thermocycling (five cycles); and 5, remineralization (synthetic saliva: six hours) for each group (n=12) for 30 (15 days) or 60 times (30 days). Specimens were analyzed using an incident light microscope. Substance loss was measured in micrometers. Statistical analysis was performed with the multiple contrast test (p<0.05).

Groups B and C had a significantly lower dentin loss than A (p<0.01). After 30 days, group A showed the highest dentin loss (p<0.01), whereas the other groups lacked a significant difference regarding their substance loss (dentin and/or varnish; p>0.05). Varnish layer loss was shown for groups D and E with a remaining protective layer; groups A-C showed dentin removal.

All four varnishes are protective compared with an untreated control. Light-curing varnishes might provide higher dentin protection than self-curing materials.