title: Evaluation of immediate bone-cell viability and of drill wear after implant osteotomies: immunohistochemistry and scanning electron microscopy analysis.
abstract: OBJECTIVE
  This study sought to evaluate the effect of repeated implant drilling on the immediate bone-cell viability, and to evaluate drill wear by scanning electron microscopy.
  
  
  METHODS
  The tibiae of 10 rabbits were used, divided into 5 groups (G): G1 corresponded to new drills, and G2, G3, G4, and G5 corresponded to drills used 10, 20, 30, and 40 times, respectively. The animals received 10 sequential osteotomies in each tibia. The animals were euthanized immediately after the osteotomies by perfusion with 4% formaldehyde. Samples then underwent immunohistochemistry processing for ordinal qualitative analysis of osteoprotegerin (OPG), the RANK ligant (RANKL; a tumor-related necrosis factor receptor family), and osteocalcin protein immunolabels, as detected by the immunoperoxidase method and revealed with 3,3-diaminobenzidine. Drill wear and plastic deformation were analyzed by scanning electron microscopy (SEM).
  
  
  RESULTS
  The proteins were expressed in osteocytes of the superior bone cortical during the 40 drillings. However, in G4 and G5, a discrete increase in the expression of RANKL was observed, when compared with OPG; this increase was statistically significant in G5 (P = .016). The SEM analysis revealed major plastic deformation and drill wear in G4 and G5.
  
  
  CONCLUSIONS
  Based on the present methodology, it may be concluded that cell viability is preserved if a less traumatic surgical protocol is used. However, the repeated use of drills alters the protein balance as of the thirtieth perforation.
authors.affiliation: Dental School of Araçatuba, São Paulo State University Júlio de Mesquita Filho, São Paulo, Brazil. thaqueiroz@hotmail.com
authors.forename: Thallita Pereira
authors.initials: TP
authors.lastname: Queiroz
authors.forename: Francisley Avila
authors.initials: FA
authors.lastname: Souza
authors.forename: Roberta
authors.initials: R
authors.lastname: Okamoto
authors.forename: Rogério
authors.initials: R
authors.lastname: Margonar
authors.forename: Valfrido Antônio
authors.initials: VA
authors.lastname: Pereira-Filho
authors.forename: Idelmo Rangel
authors.initials: IR
authors.lastname: Garcia Júnior
authors.forename: Eduardo Hochuli
authors.initials: EH
authors.lastname: Vieira
mesh_terms: D000818:Animals; D001831:Body Temperature; D002470:Cell Survival; D003754:Dental High-Speed Equipment; D003758:Dental Implantation, Endosseous / Q000295:instrumentation*; D017743:Equipment Reuse; D007124:Immunoenzyme Techniques; D008297:Male; D008855:Microscopy, Electron, Scanning; D015675:Osteocalcin / Q000096:biosynthesis; D010011:Osteocytes / Q000378:metabolism / Q000502:physiology*; D053244:Osteoprotegerin / Q000096:biosynthesis; D010027:Osteotomy; D053245:RANK Ligand / Q000096:biosynthesis; D011817:Rabbits; D018124:Receptors, Tumor Necrosis Factor / Q000096:biosynthesis; D013977:Tibia
chemical_list: D053244:Osteoprotegerin; D053245:RANK Ligand; D018124:Receptors, Tumor Necrosis Factor; D015675:Osteocalcin