The use of dentin sealers before crown cementation can reduce postcementation sensitivity. Various sealer materials are used, including resin-based sealers. A study by Johnson, et al assessed the retention of cemented castings after application of a resin-based dentin sealer.
The study involved 55 extracted human molars, which were prepared with a flat occlusal surface, a 20º taper, and an axial length of 4 mm. After the teeth were prepared, a 2-step, single-bottle adhesive system was applied as a sealer. Castings of ceramometal high-noble alloy were then cemented into place using 3 different luting agents: zinc phosphate, glass ionomer, or modified-resin cement along with the single-bottle adhesive. After thermocycling, the castings were removed along the path of insertion, and dislodgment stress and the mode of failure were determined.
The study found the sealer decreased the retentive stress by 42% for the zinc phosphate cement group. However, the resin-based sealer increased crown retention 55% when the casting was cemented with glass ionomer. Mean dislodgment stress was significantly greater with the modified resin cement and usually was greater than the tooth strength. The study concludes that a resin-based dental primer/adhesive is recommended when castings are cemented with glass ionomer or modified resin cement, but is not recommended for cementation with zinc phosphate.
(Source: Dental Abstracts, Vol. 50, Issue 1, 2005)
