RESTORATIVE DENTAL MATERIALS

Introduction: Erosion is an escalating problem in all age groups. Dental erosioncan be defined as painless irreversible loss of dental hard tissue due to chemical processwithout the involvement of microorganisms. There are several causes of erosion includingacidic foods and drinks. They are not only harmful to teeth but it is one of the main causes offailure of restoration. Erosion is one of the main challenges to restorative materials. Therefore,the restorative materials used in the mouth should resist or show minimal change in thesesituations. A variety of restorative materials are currently recommended for erosive lesions,including resin modified glass ionomer cement, resin composite and amalgam. Each materialhas its own advantages and disadvantages, which are considered before selecting them asrestorative materials. Objectives: To compare the surface micro-hardness of three restorativematerials when exposed to three acidic beverages and distilled water. Study design: This wasan experimental study. Setting: de’Montmorency College of dentistry in collaboration withPakistan council of scientific and industrial research (PCSIR) Lahore. Period: 6 months, Nov2014- April 2015. Material & Methods: Ninety six disc specimens prepared with resin modifiedglass ionomer, resin composite and amalgam restorative materials. The initial surface microhardnesstest was carried out at 1 day after mixing (before immersion) using micro-hardnesstesting machine. After base line study of micro-hardness the material specimens were subjectedto one of the storage media which was comprised of cola, apple juice, orange juice and distilledwater as control. Quantitative assessment of final surface micro-hardness was done at 2, 5 and7 days after immersion. The values obtained as base line and final vickers hardness number(VHN) for each specimen were subjected to statistical analysis. Results: Exposure to acidicbeverages decreased the surface micro-hardness of all the three restorative materials (P<0.05),while distal water did not affect the surface micro-hardness of any material. The resin modifiedGIC showed greatest reduction in surface micro-hardness as compared to Amalgam and ResinComposite. The cola produced the greatest degradation effect. Conclusion: Selection ofrestorative materials should be considered in patients with tooth surface loss, especially thosewith high risk for erosive conditions. In terms of materials evaluated for this study Amalgam andResin Composite provides the greatest stability under acidic conditions.