title: The comparison of the effects of different whitening toothpastes on the micro hardness of a nano hybrid composite resin.
abstract: OBJECTIVE
  The aim of this study was to compare the micro hardness of a nanohybrid composite resin after brushing with two herbal and one non-herbal whitening toothpastes.
  
  
  METHODS
  We divided Eighty disk-shaped specimens of a nanohybrid composite (Tetric N Ceram, Ivoclar Vivadent, Asia) into 4 groups of 20 specimens each: Groups A, B, C, and D. Group A was control, Group B was brushed with Colgate total advanced whitening (Colgate-Palmolive (India) Limited), Group C with Salt and Lemon, Dabur (Dabur International Limited, Dubai, UAE), and Group D with HiOra Shine, Himalaya (The Himalaya Drug Company, India). The specimens were polished using medium, fine, and superfine discs (Sof-lex, 3M, ESPE, USA) and subsequently placed at 37°C in distilled water. They were brushed for 2 minutes twice daily with a soft motorized toothbrush (Colgate 360 sonic power battery-operated tooth brush, Colgate Palmolive, India) for 30 days. The samples were rinsed under running water to remove the toothpaste and stored in distilled water at 37°C until the readout was taken on the Vickers's hardness tester for microhardness.
  
  
  RESULTS
  The results revealed that the difference among the groups was statistically significant (P < 0.001). Tukey's test showed that reduction in microhardness for Group B was significantly higher than that for Group C and Group D (P < 0.001).
  
  
  CONCLUSIONS
  Within the limitations of this study, non-herbal whitening toothpaste had a greater impact on the microhardness of nanohybrid resin composite than herbal whitening toothpastes.
authors.affiliation: Department of Conservative Dentistry and Endodontics, Vydehi Institute of Dental Sciences and Research Centre, Bangalore, Karnataka, India.
authors.forename: Mohan Thomas
authors.initials: MT
authors.lastname: Nainan
authors.affiliation: Department of Conservative Dentistry and Endodontics, Vydehi Institute of Dental Sciences and Research Centre, Bangalore, Karnataka, India.
authors.forename: Ashok Kalappurakkal
authors.initials: AK
authors.lastname: Balan
authors.affiliation: Department of Conservative Dentistry and Endodontics, Vydehi Institute of Dental Sciences and Research Centre, Bangalore, Karnataka, India.
authors.forename: Roshni
authors.initials: R
authors.lastname: Sharma
authors.affiliation: Department of Conservative Dentistry and Endodontics, Vydehi Institute of Dental Sciences and Research Centre, Bangalore, Karnataka, India.
authors.forename: Sabeena Susan
authors.initials: SS
authors.lastname: Thomas
authors.affiliation: Department of Mechanical Engineering, Reva Institute of Technology and Management, Bangalore, Karnataka, India.
authors.forename: Santhosh B
authors.initials: SB
authors.lastname: Deveerappa
keywords: Abrasives in toothpaste; Vickers hardness test; herbal toothpaste; microhardness; resin composites; tooth whitening