Are insertion torque and early osseointegration proportional? A histologic evaluation

Felipe E.B. Campos, Ryo Jimbo, Estevam A. Bonfante, Darceny Z. Barbosa, Maiolino T.F. Oliveira, Malvin N. Janal, Paulo G. Coelho

Research output: Contribution to journalArticlepeer-review


Objectives: The objective of this histologic study was to determine the effect of three drilling protocols (oversized, intermediate, and undersized) on biologic responses to a single implant type at early healing periods (2 weeks in vivo) in a beagle dog model. Materials and methods: Ten beagle dogs were acquired and subjected to surgeries in the tibia 2 weeks before euthanasia. During surgery, each dog received three Unitite implants, 4 mm in diameter by 10 mm in length, in bone sites drilled to 3.5, 3.75, and 4.0 mm in final diameter. The insertion torque was recorded during surgery, and bone-to-implant contact (BIC), and bone area fraction occupied (BAFO) measured from the histology. Each outcome measure was compared between treatment conditions with the Wilcoxon signed-rank test. Bonferroni-corrected statistical significance was set to 95%. Results: Insertion torque increased as an inverse function of drilling diameter, as indicated by significant differences in torque levels between each pair of conditions (P = 0.005). BIC and BAFO levels were highest and statistically similar in the recommended and undersized conditions and significantly reduced in the oversized condition (P < 0.01). Conclusions: Reduced drilling dimensions resulted in increased insertion torque (primary stability). While BIC and BAFO were maximized when drilling the recommended diameter hole, only the oversized hole resulted in evidence of statistically reduced integration.

Original languageEnglish (US)
Pages (from-to)1256-1260
Number of pages5
JournalClinical Oral Implants Research
Issue number11
StatePublished - Nov 2015


  • Histomorphometry
  • Implant
  • Initial stability
  • Insertion torque
  • Osseointegration

ASJC Scopus subject areas

  • Oral Surgery


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