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38 Cards in this Set
- Front
- Back
Access prep need to be:
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smooth axial walls all canals visible funnel shaped straight line access safe irrigation straighten out curves |
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disadvantages of traditional files
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increasingly inflexible as they increase in size canals are rarely an 02 taper use a lot of instruments, if continually rotated they will fracture can easily create ledges can push debris into the canal and cause blockages very time consuming |
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NiTi File properties
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used in a continuous motion have modified cutting edges to prevent binding in the canal non cutting tips which allow the files to remain centred in the canal have radial lands which prevents locking in the dentine rake angle is usually negative or neutral the grooves allows removal of debris however do produce a thick smear layer used for canal enlargement not negotiation |
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protaper file properties
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shaper x file = 3.5-19% taper up to 9mm then 2% taper 10-14mm shaper 1 file = 2-11% taper up to 14mm shaper 2 file = 4-11.5% taper up to 14mm |
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contraindication for using rotary files |
very curved canals s-shaped canals apical hooks canals with sharp elbows if a glide path cannot be formed |
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advantages of NiTi files
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flexible good deep shape less debris extrusion faster fewer files used more predictable results |
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disadvantages of NiTi files |
torsional and flexural failures and fractures |
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methods for determining working length |
paperpoint technique radiographic electronic apex locator |
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Types of Apex
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radiographical major apical constriction minor apical constriction CDJ |
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problems with electronic apex locators
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perforation trigger a response large canals can cause misreading |
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most common pathways for bacterial entry into the canal
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cracks exposed dentine broken down restorations |
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reasons for placing an interim restoration
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support for weakened cusps coronal seal rubber dam easy to apply ideal cavity can be cut no risk of leaking irrigants a temp restoration will be better retained more comfortable and functional for the patient can be used as a core for an indirect restoration |
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why would you remove a crown before endo?
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identify hidden pathology better orientation better coronal seal |
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main requirements of a temporary restoration
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easily removable obvious difference between this and tooth tissue/interim restoration inexpensive |
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why protect posterior teeth undergoing endo? |
access cavity loss of marginal ridges axial forces can flex cusps non-axial forces are even more damaging |
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options for protecting posterior teeth
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cusp reduction and overlay onlay/overlay indirect restoration full crown |
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properties of irrigants
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removes debris/nectrotic/inflamed tissue removes dentine debris and smear layer provides lubrication |
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obstacles in the way of irrigation
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smear layer fluid dynamics biofilm resistant microbiota |
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smear layer consists of... |
odontoblast processes, bacteria necrotic debris it provides protection for bacteria |
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what kind of needle used to irrigate and why?
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stop locking into the canal and stops apical pressure |
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ideal characteristics of an endo irrigant
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non-irrigating to the periapical tissue stable in solution prolonged antimicrobial action active in the presence of blood/proteins/serum low surface tension not interfere with periapical healing not stain tooth tissue not cause allergic reaction completely remove smear layer non toxic, non-antigenic, non-carcinogenic no reaction with filling materials easy to use inexpensive |
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types of irrigant and strengths |
EDTA - 17% Chlorhexidine - 0.2-2% Iodine potassium iodide - 2% iodine in 4% potassium iodide hydrogen peroxide 3-5% MTAD - 3% doxycycline, 4.25% citric acid Photo activated disinfection electronically activated water |
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NaOCl advantages and disadvantages
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dissolves organic matter and biofilm, antimicrobial, affordable Disadvantages: minimally removes smear layer, reduces flexural strength of dentine, can cause allergies, toxic to vita tissues, corrodes metal instruments |
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EDTA Advantages and disadvantages
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disadvantages: not bactericidal, overuse causes excessive removal of dentine |
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Chlorhexadine advantages and disadvantages
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disadvantages: forms brown precipitate with NaOCl, no tissue dissolving effects, cannot remove smear layer, potential for allergic reaction |
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iodine potassium iodide advantages and disadvantages
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disadvantages: can stain dentine, not stable in presence of organic material, no tissue dissolving properties, unable to remove smear layer |
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hydrogen peroxide advantages and disadvantages
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disadvantages : antimicrobial and tissue dissolving less than NaOCl, can release bubbles and cause emphysema, nolonger used as routine |
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MTAD advantages and disadvantages
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advantages: borad spectrum antimicrobial, acid removed smear layer, no adverse effects on the tooth disadvantages: less efficient on biofilm, more toxic than NaOCl, expensive, risk of bacterial resistance and tetracycline staining |
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reversible pulpitis signs and treatment |
treat the causative factor, tell them to take analgesics and pain will reduce |
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irreversible pulpitis signs and treatment
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spontaneous pain that lasts for hours, triggered by heat, reliveed by cold, kept awake at night, ttp, pain radiates and can get worse treatment: try and complete RCT |
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Hot pulps - alternatives to normal LA
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regional anaesthesia, lignocaine and articaine, intraligamentary, intra pulpal, intraosseous, sedation |
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periapical periodontitis - signs and treatment |
tender to percuss and palpate, swelling and reddening of the mucosa, to response to vitality testing, pain severe in function, can be constant or worsening, can be present for hours treat by placing CaOH and bacteria tight seal and re-visiting |
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acute apical abscess - signs and treatment
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treat by drainage though incision, extraction or rct, give antibiotics at signs of spreading infection |
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cracked tooth - causes, signs, treatment
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signs - pain on chewing, sensitivity to hot and cold, difficult to locate pain, fracture line mesial to distal treat with ortho band, replace restoration, rct if needed. |
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complicated crown fracture in permanent teeth treatment
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partial pulpotomy rct |
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primary teeth pulp treatment
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extraction no-vital tooth = pulpectomy |
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principles of electronic apex locators
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2 or more currents are varying frequency are emitted, the impedence of the tissues surrounding the file is compared to the impedence of the buccal mucosa. when the values match then the file is deemed to be at the apex |
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why can it be difficult to anaesthetise in pulpitic cases
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