title: An Invitro Comparative Evaluation of Compressive Strength and Antibacterial Activity of Conventional GIC and Hydroxyapatite Reinforced GIC in Different Storage Media.
abstract: BACKGROUND
  GIC is the most commonly used restorative material in pediatric dentistry since it has got various advantages like fluoride release, anticariogenic property and chemical adhesion to tooth but a major disadvantage is its contraindication in posterior teeth because of poor mechanical properties.
  
  
  OBJECTIVE
  The purpose of this study is a modest attempt to explore the influence of the addition of 8% hydroxyapatite to conventional GIC on its compressive strength when immersed in different storage media and antibacterial activity.
  
  
  METHODS
  One hundred and twenty six pellets of the specific dimension of 6 x 4 mm were prepared and divided into 6 groups and were immersed in deionized water, artificial saliva, lactic acid solution respectively for three hours everyday over 30 days test period. The compressive strength was measured by using a universal testing machine (AG-50kNG) at cross head of 1mm(2)/min and strength was determined after 1 day, 7 days, 30 days respectively and the antibacterial activity evaluated against Streptococcus mutans strain in brain heart infusion broth using serial dilution method.
  
  
  METHODS
  Group wise comparisons were made by one-way ANOVA followed by post-hoc Tukey's test, Intergroup comparison was done with Mann-Whitney test.
  
  
  RESULTS
  GIC±HAp showed significantly greater antibacterial activity against Streptococcus mutans when compared to GIC group. There was no statistically significant change in the compressive strength among the groups except for group 3 and group 6 when immersed in lactic acid had shown significant difference at the end of 24 hours.
  
  
  CONCLUSIONS
  The addition of 8% hydroxyapatite to GIC showed marked increased in the antibacterial activity of the conventional GIC against caries initiating organism without much increase in the compressive strength of the GIC when immersed in the different storage media.
authors.affiliation: Senior Lecturer, Department of Pedodontics and Preventive Dentistry, College of Dental Sciences , Davangere, Karnataka, India .
authors.forename: Praveen
authors.initials: P
authors.lastname: Bali
authors.affiliation: Professor and Head, Department of Pedodontics and Preventive Dentistry, Bapuji Dental College & Hospital , Davangere, Karnataka, India .
authors.forename: Attiguppe Ramasetty
authors.initials: AR
authors.lastname: Prabhakar
authors.affiliation: Professor, Department of Pedodontics and Preventive Dentistry, Bapuji Dental College & Hospital , Davangere, Karnataka, India .
authors.forename: Nadig
authors.initials: N
authors.lastname: Basappa
keywords: Broth dilution technique; Mechanical properties; Storage media; Streptococcus mutans; Universal testing machine