Effects of Mechanical and Thermal Fatigue on Dental Drill Performance

Benjamin H. Harris, Sean S. Kohles

Research output: Contribution to journalArticlepeer-review

42 Scopus citations


Osseous integration of dental implants depends on the use of proper surgical technique during site preparation, including the prevention of thermal injury to the surrounding bone. Heat generation during drilling has been reported to positively correlate with the production of forces at the surgical site. In this study, peak torque and axial load levels were measured during a drilling procedure into a polymeric material simulating the human mandible. Axial rotary milling was performed using 5 different twist drill designs (3i Irrigated Tri-Spade, 3i Disposable, Nobel-Biocare, Straumann, and Lifecore) of 15 to 20 mm in length and 2 to 2.3 mm in diameter, at a free-running rotational speed of 1,500 rpm and continuous feed rate of 3.5 mm/second, to a total depth of 10.5 mm. Ten drills representing each of the 5 types (n = 50) were subjected to 30 individual drill "pecks" and heat-sterilized every 3 "pecks" to determine the effects of cyclic mechanical and thermal loading on drill performance. Normal stress (σ) and shear stress (τ) were calculated from the kinetic data and drill geometries. A drill efficiency coefficient (μ) was also calculated as the ratio of torsional resistance to translational resistance. Overall, the hypotheses of drill performance dependency on drill type as well as mechanical and thermal accumulated loading were tested and confirmed (P < .05). The 5 drill types produced a range of normal stresses (2.54 to 5.00 MPa), shear stresses (9.69 to 29.71 MPa), and efficiency (1.16 to 3.16) during repeated testing. Scanning electron microscopic images revealed minor deformations in the cutting edges of the tri-spade drills following testing.

Original languageEnglish (US)
Pages (from-to)819-826
Number of pages8
JournalInternational Journal of Oral and Maxillofacial Implants
Issue number6
StatePublished - 2001


  • Dental instruments
  • Mechanical stress
  • Operative dentistry
  • Torque

ASJC Scopus subject areas

  • Oral Surgery


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