Scanning Electron Microscopic Evaluation of Composite Resin-Dentin, Calcium Hydroxide-Dentin and Resin- Calcium Hydroxide Interfacial Gap with Composite Resin Restorations- An in vitro Study

The dental pulp has been shown to have its own reparative capacity and is capable not only of healing but also of providing a dentinal bridge in the absence of calcium hydroxide. The present study was performed to evaluate interfacial gaps formed due to polymerization shrinkage of composite resin. 20 Maxillary or Mandibular, freshly extracted human third molars were prepared and filled using composite with a calcium hydroxide base. The samples were divided into two groups based on primer/bonding agent used i.e. Scotchbond multipurpose (Group I) and Single bond (GroupII). Sectioned samples were gold sputtered and analyzed using Scanning Electron Microscope (SEM). The interfacial gap in specimens belonging to group I and II was observed at the 3 interfaces viz; Calcium hydroxide-dentin interface (A), Composite resin calcium hydroxide interface (B) and Composite resin dentin interface (C). The interfacial gap formed between calcium hydroxide and dentin (A) was highly significant (p <0.01) in both groups i.e. Group I and Group II, when it was compared with ‘B’ and ‘C’ of the same group. There was no statistical significant difference between group ‘B’ and ‘C’. Thus in both the groups an interfacial gap was found between the calcium hydroxide and dentin. Interposition of calcium hydroxide between tooth and resin possesses some clinical disadvantages and is recommended in selective clinical situations.