BACKGROUND Dacrocystorhinostomy (DCR) is an operation used to treat nasolacrimal duct obstruction. Essentially there are two approaches: external and endoscopic. Several modalities are used in endoscopic DCR; all aiming to improve success rate, reduce complications, and shorten operative time. Both kerrison punch and drill are widely used in endoscopic DCR with non-conclusive knowledge about di...

OBJECTIVES To compare the noise and vibration levels associated with three hand-held rock drills (pneumatic, hydraulic and electric) currently used in South African mines, and a prototype acoustically shielded self-propelled rock drill. METHODS Equivalent A-weighted sound pressure levels were recorded on a geometrical grid, using Rion NL-11 and NL-14 sound level meters. Vibration measurements...

The fast monitoring of tool wears by using various Cutting signals and the prediction models developed rapidly in recent years. Comparatively, various wear forecast models based on artificial neural networks (ANN) perform much better in accuracy and speediness than the conventional prediction models. Combining the prominent dynamic properties of back propagation neural network (BPNN) with the e...

OBJECTIVES The purpose was to assess thermal changes and drill wear in bovine bone tissue with the use of twisted stainless steel and zirconia-based drills, during implant site preparation. METHODS A total of 100 implant site preparations were performed on bovine ribs using a surgical unit linked to a testing device, in order to standardize/simulate implant drilling procedures. Bone temperatu...

The distinguishing characteristics of carbon fibre reinforced laminates, like low weight, high strength or stiffness, had resulted in an increase of their use during the last decades. Although parts are normally produced to “near-net” shape, machining operations like drilling are still needed. In result of composites non-homogeneity, this operation can lead to delamination, considered the most ...

In order to understand critical vibration of a drill bit such as stick-slip and bit-bounce and their wave propagation characteristics through a drill string system, it is critical to model the torsional, longitudinal, and flexural waves generated by the drill bit vibration. Here, a modeling method based on a vibration transfer matrix between two sets of structural wave variables at the ends of ...

STUDY DESIGN Cadaveric study. PURPOSE The purpose of this study was to assess the accuracy and feasibility of cervical pedicle screw (CPS) insertion into the subaxial cervical spine placed using a patient-specific drill guide template constructed from a stereolithographic model. OVERVIEW OF LITERATURE CPS fixation is an invaluable tool for posterior cervical fixation because of its biomecha...