1. EQUIPMENT IN L.A. Equipment has been developed for LA administration to be convenient in use and to be sterile ( read history). Sterilization: removal of all micro-org. (vegetative&spores). Equipment has been developed for LA administration to be convenient in use and to be sterile ( read history). Sterilization: removal of all micro-org. (vegetative&spores). Dentist must not introduce infection by his instruments, Dentist must not introduce infection by his instruments, syringes, needles, forceps---etc. syringes, needles, forceps---etc. Autoclave (moist heat): 120 c/10-12min. Dry heat (hot-air oven):160c/ 60 min. Autoclave (moist heat): 120 c/10-12min. Dry heat (hot-air oven):160c/ 60 min. Water boiling (at normal temper.&pressure):100c/5-10 min. (spores will resist boiling for 60 min., fungi& threads resist boiling for 20 min.) Water boiling (at normal temper.&pressure):100c/5-10 min. (spores will resist boiling for 60 min., fungi& threads resist boiling for 20 min.) Water boiling: used for many years. It kills vegetative org.& fortunately most pathogenic bacteria are in this phase. (pathogenic& potential pathogenic). Water boiling: used for many years. It kills vegetative org.& fortunately most pathogenic bacteria are in this phase. (pathogenic& potential pathogenic).

2. LA Instruments S yringes,needles& cartridges S yringes,needles& cartridges A - SYRINGES: plastic& metal syringes (barrel, plunger & double ended-needle hub). Plunger united by spring- loaded hinge mechanism. syringes are : aspirating & non- aspirating. syringes are : aspirating & non- aspirating. Before sterilization : disinfection of syringes & needles, but recently, pre-sterilized needles (st.st.), was a great help in the chain of sterility. Before sterilization : disinfection of syringes & needles, but recently, pre-sterilized needles (st.st.), was a great help in the chain of sterility.

3. Development of instruments: Development of instruments: 1- disposable syringe & needle in a sleeve.Cartridge introduced. 1- disposable syringe & needle in a sleeve.Cartridge introduced. 2- disposable needle assembly with metal handle(needle& cartridge). 2- disposable needle assembly with metal handle(needle& cartridge). 3- disposable aspirating syringe & a special cartridge. 3- disposable aspirating syringe & a special cartridge.

4. B- Needles Hypodermic needles: short 2-2.5cm Hypodermic needles: short 2-2.5cm long 3.5cm long 3.5cm choice of needles: must penetrate to the depth required before complete length enters tissue( to be grasped by pliers& removed). choice of needles: must penetrate to the depth required before complete length enters tissue( to be grasped by pliers& removed). gauge: fine needles comfortable but may cause damage to blood vessels, muscles, ligaments( hematoma & trismus). gauge: fine needles comfortable but may cause damage to blood vessels, muscles, ligaments( hematoma & trismus). - Tissue may deflect the needle& so an inaccurate placement of solution. Acceptable gauge is: gauge 27 or the finer gauge 30. - Tissue may deflect the needle& so an inaccurate placement of solution. Acceptable gauge is: gauge 27 or the finer gauge 30. Acute angled,double beveled needle tip is easier on insertion in the tissue, but more easily damaged when in contact with bone. Acute angled,double beveled needle tip is easier on insertion in the tissue, but more easily damaged when in contact with bone. The other needle tip (standard), is straight& short bevel. The other needle tip (standard), is straight& short bevel.

5. C - Cartridge supplied pre-sterilized. supplied pre-sterilized. Alkali & pyrogen free glass used by manufacturer. Alkali & pyrogen free glass used by manufacturer. Sealing cap which pierced by the needle varies in design. Cartridge contains (1.8ml. Which is sufficient or 2.2 ml). Sealing cap which pierced by the needle varies in design. Cartridge contains (1.8ml. Which is sufficient or 2.2 ml). N.B.: after releasing pressure, slight aspiration occurs. So, contamination of the left solution happen& accordingly: do not use what is left for another patient to avoid spread of infection. Yes, it is a waste but accepted if using large cartridge. N.B.: after releasing pressure, slight aspiration occurs. So, contamination of the left solution happen& accordingly: do not use what is left for another patient to avoid spread of infection. Yes, it is a waste but accepted if using large cartridge.

6. LA EQUIPMENT STERILIZATION 1-Dental surgeon: must have autoclave, hot-air oven or at least boiling water. 2- Hypodermic needles: the lumen of the hypodermic needle can not be sterilized and in addition to that, the heat will affect the temper of steel with the consequence risk of breakage. St.steel hypodermic needles, now, are available pre-sterilized& in a plastic container with a seal. The seal must be checked for breakage & if so, it must be discarded. St.steel hypodermic needles, now, are available pre-sterilized& in a plastic container with a seal. The seal must be checked for breakage & if so, it must be discarded. Use hypodermic needle for one patient otherwise spread of infection Use hypodermic needle for one patient otherwise spread of infection

7. solution (LA) : (Cont’) solution (LA) : (Cont’) are supplied sterile.This is the concern of the manufacturer for their reputation. are supplied sterile.This is the concern of the manufacturer for their reputation. The outside of the cartridge is exposed for contamination by air-borne organisms, careless storage, or careless handling. So, follow a standard practice, to ensure the sterilization of the needle and the cartridge. Storage of cartridge in sterilizing solution is contra- indicated to avoid contamination by seepage. Storage of cartridge in sterilizing solution is contra- indicated to avoid contamination by seepage. Dry heat( gas-jet) is most effective: sealed cap-end of cartridge for 5 seconds. sealed cap-end of cartridge for 5 seconds. warm solution by passing cartridge for 4-5 times. warm solution by passing cartridge for 4-5 times. Do not overheat solution, to reduce discomfort. Do not overheat solution, to reduce discomfort.