title: Effect of rotary cutting instruments on the resin-tooth interfacial ultra structure: An in vivo study.
abstract: OBJECTIVE
  To evaluate the effect of cutting teeth with different types of burs at various speeds on surface topography of tooth surface and interfacial gap formation at resin-tooth interface.
  
  
  METHODS
  The human molars were divided into seven groups: Diamond bur in airrotor (DA) & micromotor (DM), crosscut carbide bur in airrotor (CCA) & micromotor (CCM), plain carbide bur in airrotor (CA) & micromotor (CM) and #600-grit silicon carbide paper (SiC). In five samples from each group Class II box-only cavities were restored. The occlusal surface of four teeth per group was flattened. Two out of four teeth were acid etched. Teeth were subjected for scanning electron microscopy (SEM).
  
  
  RESULTS
  Interfacial gap was observed in all groups with no significant difference. SEM observations revealed CA, CCA & DA were coarser than CM, CCM, DM and SiC. SEM of etched tooth surfaces revealed complete removal of amorphous smear layer in CA & CM, partial removal in CCA, CCM, DA & DM and no removal in SiC.
  
  
  CONCLUSIONS
  Selecting an appropriate bur and its speed may not play an important role in bonding in terms of interfacial gap formation. Variable changes were observed in surface topography with different burs before and after acid etching. Key words:Surface topography, resin-tooth interface, interfacial gap, bonding.
authors: Consultant, Department of Conservative Dentistry & Endodontics, Post Graduate Institute of Dental Sciences, Rohtak.
authors: Sudhir
authors: S
authors: Sherawat
authors: Professor and Head, Department of Conservative Dentistry & Endodontics, Post Graduate Institute of Dental Sciences, Rohtak.
authors: Sanjay
authors: S
authors: Tewari
authors: Professor, Department of Conservative Dentistry & Endodontics, Post Graduate Institute of Dental Sciences, Rohtak.
authors: Jigyasa
authors: J
authors: Duhan
authors: Post Graduate Demonstrator, Department of Conservative Dentistry & Endodontics, Post Graduate Institute of Dental Sciences, Rohtak.
authors: Alpa
authors: A
authors: Gupta
authors: Reader, Department of Conservative Dentistry & Endodontics, JCD dental college, Sirsa, Haryan.
authors: Rakesh
authors: R
authors: Singla