Tiêu đề 8- instruments ..part 2 .. ksr .. 2025.pdf ✅

instruments ... p-2 pre-cl. Op. I 1 2025 Kasr Dr_M.Bedawi Instruments “part 2” - ergonomics → study of the adaptation of the job to human being. - ergonomics is a way to work smarter not harder by designing tools, equipment, workstations & tasks to fit the job to the worker not the worker to the job. ➢ ergonomics in hand instruments : - weight → light-weight instruments (15 gm Or less). - make it hollow Or use resin material. - balance → the instrument should be equally balanced within the hand, so that the tendency to deviate the wrist is reduced. - sharpness → as a tool becomes dull, additional force is required to perform tasks. - texture → knurled handles such as crisscross patterns. - color coded → instruments are easier to be identified. ➢ ergonomics in dental handpieces : • light-weight. • built-in light sources “fiber-optic handpieces”. • adequate head size “mini-head handpieces”. • select bet. angled vs. straight shank acc. to the use. 2- ultra-sonic equipment - this technique is based on the removal of tooth material by an air-driven hand piece equipped with a diamond-coated tip that removes tooth structure by ultra-sonic energy “sono-abrasion”. - different sizes & shapes of diamond tips have been designed, enabling easy access to the occlusal & proximal tooth lesions.  as these tips are coated only on one side, trauma of the approximal side of adjacent teeth is prevented. 3-air abrasion equipment - airborne-particle abrasion is defined as → the process of altering the surface of a material through the use of abrasive particles sprayed in a focused & pin-point stream by compressed air Or other gasses. ➢ uses : - debriding pits & fissures before sealing. - micro-mechanical roughening of surfaces to be bonded (enamel, indirect composite & porcelain). - enameloplasty. - stain removal.