title: Effectiveness of commonly available surface protecting agents in maintaining microhardness of two cements.
abstract: OBJECTIVE
  To estimate the microhardness of glass ionomer cement (vitrofil) and resin modified glass ionomer cement (vitremere) in the presence and absence of different surface protections.
  
  
  METHODS
  An in-vitro experimental study.
  
  
  METHODS
  The Department of Operative Dentistry, Dr. Ishrat-ul-Ebad Khan Institute of Oral Health Sciences, Dow University of Health Sciences and the Department of Material Sciences, NED University, Karachi, from August 2011 to January 2012.
  
  
  METHODS
  Seventy-two discs of each material were made in polytetrafluoroethylene mold which was 10 mm in diameter and 2 mm in thickness. Four groups were made for each material containing 18 discs; G1/G5 (control group), G2/G6 (solid petroleum jelly), G3/G7 vernal (resin varnish), G4/G8 (nail varnish). After initial setting reaction surface protection was applied to discs. Once the surface protection was dried, discs were stored in deionized water at 37°C for 24 hours. After 24 hours, the discs were polished. Microhardness test were performed in digital microhardness tester. The results were statistically analyzed with the help of two-way ANOVA.
  
  
  RESULTS
  For glass ionomer cement the only G4 (nail varnish) differed from the G1 (control group) [p < 0.05], No significant difference was seen with other surface protection agents. For resin modified glass ionomer cement, the G7 (resin varnish) and G8 (nail varnish) gave better result from the G5 (control group).
  
  
  CONCLUSIONS
  Nail varnish and resin varnish showed better surface protection for GIC and RMGIC. The presence of toluene in nail varnish have harmful effects so should not be preferred if resin varnish is available.
authors.affiliation: Department of Dental Materials, Dr. Ishrat-ul-Ebad Khan Institute of Oral Health Sciences, Dow University of Health Sciences, Karachi, Pakistan. nazish_fawad@yahoo.com
authors.forename: Nazish
authors.initials: N
authors.lastname: Fatima
authors.forename: Syed Yawar
authors.initials: SY
authors.lastname: Ali Abidi
authors.forename: Fazal-ur-Rehaman
authors.initials: FU
authors.lastname: Qazi
authors.forename: Shahbaz Ahmed
authors.initials: SA
authors.lastname: Jat
mesh_terms: D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry; D003793:Dental Restoration, Permanent / Q000379:methods*; D005899:Glass Ionomer Cements / Q000737:chemistry*; D006245:Hardness Tests; D006801:Humans; D008422:Materials Testing; D020011:Protective Agents / Q000737:chemistry*; D019279:Resin Cements / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors
chemical_list: D003188:Composite Resins; D005899:Glass Ionomer Cements; D020011:Protective Agents; D019279:Resin Cements