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 (Group II). 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.

Effect of wetness on the enamel bonding / 대한치과보존학회지

This study evaluated the microleakage and interfacial gap between enamel and composite resin under the dry and wet condition of the enamel surface. V shaped class 5 cavities were prepared on the occlusal portion of extracted human molars. Samples were divided into three groups: D group (air dry for 10-15 s), BD group (blot dry with moist cotton pellet), and DR group (air dry for 10-15 s and rewet with Aqua-Prep F for 20 s). Cavities were filled using Aelitefil composite resin after applied One-Step. Microleakage was tested by 2% methylene blue dye solution and the data were statistically analysed by Kruskal-Wallis test and Mann-Whitney test. Also Enamel-resin interface was observed under SEM. Group BD showed statistically lower microleakage than group D (p 0.05). At the enamel-resin interface, group D showed the gap of 2 microm thickness, but group BD and DR showed close adaptation. In conclusion, the use of blot dry and rewetting agent (Aqua-Prep F) resulted in decreased microleakage and improved adhesion between enamel and resin when using One-Step.