title: Analysis of the influence of implant shape on primary stability using the correlation of multiple methods.
abstract: OBJECTIVE
  The purpose of this study was to analyze the influence of the shape of various implants and the density of substrate on primary stability using a combination of methods.
  
  
  METHODS
  Fifty-four Neodent® brand cylindrical and conical implants with different prosthetic platforms were used. Implants were inserted into a pork rib bone and polyurethane blocks. Primary stability was assessed by insertion torque (IT), resonance frequency analysis (RFA), and pullout strength. Screws were also analyzed by scanning electron microscopy (SEM) before insertion and after removal to justify their use for inserting in different substrates.
  
  
  RESULTS
  The conical cone morse implant had the highest average for all of the assays performed and was significantly different (p < 0.05) from the cylindrical implants for IT in the bone, pullout strength in the 40 per cubic foot (PCF) polyurethane, and the bone. The internal hex cylindrical implant had the lowest averages, which were significantly different (p < 0.05) from the conical implants for IT and RFA in the bone, pullout strength in the 40 PCF polyurethane, and the bone. The IT, RFA, and pullout strength assays were moderately correlated, and the photomicrographs did not reveal changes in the implants.
  
  
  CONCLUSIONS
  The analysis of different implants showed a better primary stability of tapered implants; the density of the substrate influences the primary stability and the 15 PCF polyurethane was not adequate to evaluate primary stability; correlation was obtained between the different methodologies of analysis of primary stability.
  
  
  CONCLUSIONS
  The study shows the influence of different implant macro-geometries and densities of substrates on primary stability.
authors: Department of Dental Materials and Prosthesis, School of Dentistry of Ribeirão Preto, University of São Paulo, Av. do Café, s/n, Ribeirão Preto, SP, 14040-904, Brazil.
authors: Mariana Lima da Costa
authors: ML
authors: Valente
authors: Department of Dental Materials and Prosthesis, School of Dentistry of Ribeirão Preto, University of São Paulo, Av. do Café, s/n, Ribeirão Preto, SP, 14040-904, Brazil.
authors: Denise Tornavoi
authors: DT
authors: de Castro
authors: Department of Biomechanics, Medicine, and Rehabilitation of Locomotive Apparatus, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
authors: Antonio Carlos
authors: AC
authors: Shimano
authors: Department of Biomaterials, School of Dentistry of Uberaba, Uberaba, Brazil.
authors: César Penazzo
authors: CP
authors: Lepri
authors: Department of Dental Materials and Prosthesis, School of Dentistry of Ribeirão Preto, University of São Paulo, Av. do Café, s/n, Ribeirão Preto, SP, 14040-904, Brazil. andreare73@yahoo.com.br.
authors: Andréa Cândido
authors: AC
authors: dos Reis
mesh_terms: D000818:Animals; D003757:Dental Implantation / Q000295:instrumentation / Q000379:methods; D015921:Dental Implants; D006801:Humans; D013552:Swine
chemical_list: D015921:Dental Implants
keywords: Bone substitutes; Dental implants; Osseointegration; Scanning electron microscopy; Torque