Theoretical prediction of pullout strengths for dental and orthopaedic screws with conical profile and buttress threads

•The dental, trauma, and spinal screw groups were used to evaluate the accuracy of the calculated pullout strengths using different formulae.•The experimental tests were conducted to compare the measured and calculated pullout strengths.•The buttress threads possess significantly higher pullout strength than the triangle and square ones. However, only thread diameter, pitch, and depth are considered and modeled by the existing formulae.