Vol.:(0123456789) 1 3 Journal of the Brazilian Society of Mechanical Sciences and Engineering (2020) 42:363 https://doi.org/10.1007/s40430-020-02449-5 TECHNICAL PAPER Efect of surface topography on pull‑out strength of cortical screw after ultrasonic bone drilling: an in vitro study Raj Agarwal 1  · Vivek Jain 1  · Vishal Gupta 1  · Sanjai Saxena 2  · Vagish Dwibedi 2 Received: 29 January 2020 / Accepted: 1 June 2020 © The Brazilian Society of Mechanical Sciences and Engineering 2020 Abstract Drilling of bone is required to repair and align the bone when faced with a major fracture. The screw and implant are used for fxing the fractured part of the bone. The failure of osteosynthesis is due to strength between the bone and screw, which majorly depends upon the pull-out strength of the cortical screw. Pull-out strength is the force required to pull a screw out of its foundation from the bone. After the fxation of cortical screws, the major forces acting on the fxation of the screw and the implanted device in the bone. Therefore, it needs to make sure that the screw must ft into the place and grasp the bone within the drilled hole. The intended focus of this research is to see the efect of surface roughness induced during the bone drilling operation on pull-out strength with rotary ultrasonic bone drilling (RUBD) and standard conventional bone drilling (CBD). This is observed that a drilled hole in a bone exhibits greater pull-out strength with more surface roughness because more anchoring is provided by the roughened surface. Also, the apatite formation of the bone shows the biocompatible nature of porcine bone in the simulated body fuid (SBF) solution. RUBD using diferent grit size in a hollow drilling burr resulted that coarse abrasive have maximum efort for higher surface roughness. Furthermore, the higher surface texture provides a better bone growth rate as it provides peaks for branching and nucleation when preserved in SBF. RUBD provides precise cutting to the bone as compared to CBD. On the 28th day of the bone-screw samples to be immersed in SBF results 42.82% higher pull-out strength of screw in case of RUBD as compared to CBD. Keywords Rotary ultrasonic bone drilling · Surface roughness · Microcracks · SBF · Pull-out strength 1 Introduction From ancient civilization, human bones need rehabilita- tion and repair when faced with major damage or accident to any body part. Bone fracture is a major health concern and a very common problem faced by living being due to aging, accidents and stressed fracture. Above 20% of ath- letes sufer from stress fractures [1]. During fracture, bone breaks or does not align with each other. For the treatment of bone fracture, most of the orthopedic surgeries are based on bone drilling for fxing plates and implants with the cortical screws. The success of implant depends upon the stability and sustainability of screws [2]. Implant failure and aseptic loosening of the cortical screw are usual problems faced by orthopedic surgeons due to less stability between the bone and cortical screw [2, 3]. This stability of cortical screw is owing to high temperature and causes failure of joint pros- theses [2]. It has been reported that the implant failure rate is around 2.1–7.1% [4]. Primary stability of implant afects the strength, rigidity, and resistance to movement of the implant before tissue healing [5]. There could be many reasons for implant failure like occlusal overload, wear or corrosion, fbrous encapsulation, infammation, fracture of implants due to mechanical failure, lack of initial implant stability, mismatch in modulus of elasticity between bone and implant which leads to revision surgery [6, 7]. Technical Editor: Adriano Almeida Gonçalves Siqueira. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s40430-020-02449-5) contains supplementary material, which is available to authorized users. * Vishal Gupta vishal.gupta@thapar.edu 1 Department of Mechanical Engineering, Thapar Institute of Engineering and Technology, Patiala 147004, Punjab, India 2 Department of Biotechnology, Thapar Institute of Engineering and Technology, Patiala 147004, Punjab, India