*Department of P.O.P, college of dentistry, university of Mosul, Mosul, Iraq. Introduction Conservation of anchorage in totality has been a perennial problem to the traditional orthodontist. Conventional means of supporting anchorage have been used by either intra oral sites or relying on extra oral means. Both of these have their limitations. The extra oral forces very difficult device and som...

In this paper, we consider the axial motion of a directional multi-sectional drill-string. The drill-string dynamics are represented by distributed dynamical model (wave equations) coupled with an ordinary differential equation at downhole boundary (bit-rock interaction). interaction between drill-bit and rock can introduce severe vibrations in result safety performance issues. Consequently, dr...

Drilling is an hole making process in metal cutting operation performed by extrusion which finds wide application in various industries for manufacturing components using metals and non metals. This process is applied widely in assembly of components or elements, where processing challenges are severe issue such as to maintain surface integrity, ovality, machining time, Metal Removal Rate etc.,...

OBJECTIVE Percutaneous cochlear implant surgery consists of a single drill path from the lateral mastoid cortex to the cochlea via the facial recess. We sought to clinically validate this technique in patients undergoing traditional cochlear implant surgery. STUDY DESIGN Prospective clinical trial. METHODS After institutional regulatory board-approved protocols, five ears were studied via t...

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...

Few Palaeogene and Neogene sediment cores from the Antarctic continental margin have been dated with sufficient precision to enable establishment of direct linkages between glacial events on the Antarctic continent and marked events in deep-sea N18O records. As a result, much of our knowledge of the gradual, but stepwise, shift from ‘greenhouse’ climates of the Cretaceous to the ‘ice-house’ cli...

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...