▁the ▁re usable ▁dent al ▁instruments ▁used ▁daily ▁in ▁dent al ▁practices ▁are ▁ster il ised ▁ade qu ately ▁after ▁each ▁use . ▁Ster il isation ▁is ▁an ▁essential ▁part ▁of ▁the ▁in fection ▁control ▁protocol . ▁This ▁can ▁be ▁defined ▁as ▁free ▁of ▁all ▁life ▁forms ▁where ▁the ▁elim ination ▁of ▁considerable ▁number ▁of ▁the ▁most ▁heat ▁resist ant ▁sp ores ▁( b acter ial ▁and ▁my c otic ) ▁is ▁the ▁basic ▁criteria ▁ster il isation . ▁Ster il isation ▁process ▁consists ▁of ▁▁ ▁Aut oc la ving ▁where ▁mo ist ▁heat ▁k ills ▁b acter ia ▁by ▁den atur ation ▁of ▁high ▁protein - ▁containing ▁b acter ia ▁at ▁ 2 5 0 F ▁( 1 2 1   ° C ) ▁for ▁ 1 5 ▁to ▁ 2 0 ▁minutes ▁or ▁ 2 7 0 ▁F ▁for ▁ 3 ▁minutes . ▁Bi ological ▁mon itors ▁and ▁Process ▁indic ators ▁are ▁ 2 ▁methods ▁used ▁to ▁ensure ▁the ▁effect iveness ▁of ▁ster il ization ▁process . ▁▁▁▁ ▁Bi ological ▁monitor ▁( sp ore ▁test ) ▁where ▁b acter ial ▁sp ores ▁are ▁placed ▁in ▁stri ps ▁or ▁en velop s ▁along ▁with ▁the ▁instruments . ▁This ▁method ▁shows ▁that ▁the ▁micro organ isms ▁have ▁been ▁er adic ated ▁and ▁must ▁be ▁conducted ▁week ly . ▁▁▁▁ ▁Process ▁indic ators ; ▁where ▁the ▁load ▁has ▁reached ▁a ▁certain ▁temperature , ▁the ▁indic ators ▁change ▁their ▁colour . ▁▁▁▁ ▁D ry ▁heat ▁ster il ization ▁which ▁requires ▁a ▁higher ▁temperature ▁and ▁longer