PROCEDURAL Flashcards
a. Objectives of pre-endo restoration (4M)
Rationale of pre-endodontic restoration:
- Rule out cracks and fractures
- Rule out and remove recurrent caries
- Ease of treatment
- Check restorability
- Creates a ‘tank’ for the irrigating solution
- Rubber dam clamp fixture
b. Advantage of coronal flaring and crown down technique (4M)
Coronal flaring and Crown down technique advantages:
- Decreased frictional stress exerted on the instruments; taper lock less likely to occur
- Removal of infected coronal part, before entering the apical part, of the root canal
- Early coronal flaring, which significantly reduces alteration of the working length during canal preparation; otherwise, as the canal is prepared, it is gradually straightened leading to alteration of the working length
- Improved access for irrigants into the apical part of the root canal, resulting in longer contact times between irrigation solutions and intracanal microorganism
- Reduced risk of apical extrusion of debris into the peri-radicular tissue, as the working instrument is not tightly confined in the canal; however, this claim lacks good supporting evidence
c. Post space/post length(?) of 15, tooth length: 18mm ;root below alveolar bone: 11mm (1M)
Since 1/3 of post the post should be below the alveolar bone and the amount of gutta percha left should ideally be 5mm
Length of post under alveolar bone = 11mm – 5mm = 6mm (1/3 of the post length)
6 x 3 = 18 mm??
Patient felt pain when having cold and hot drinks
PA of teeth 45 and 44 given
a. Post obturation restoration option (2)
Post and core, crown
Patient felt pain when having cold and hot drinks
PA of teeth 45 and 44 given
b. Tooth length 21mm, Root length 11mm. What the length of post? (1)
Assuming that the length from CEJ to alveolar bone is 2mm and that the gutta percha left is 5mm
So 1/3 of the post length = 11mm – (2mm + 5mm) = 4mm
So full length of the post is 4x3= 12 mm
a. What are the 3 uses of irrigation during endodontic treatment? (3)
Aims of irrigation
- Remove pulp tissue and/or microorganisms, smear layer, and dentin debris from the root canal system
- Neutralize endotoxins
- Lubricate canal walls and instruments
- Prevent packing of infected hard and soft tissue apically (flushing action)
b. You decided to do an access cavity for endodontic treatment for tooth 36. What are the 4 aims and objectives for an access cavity? (4)
Criteria for access cavity
- To remove the entire roof of the pulp chamber so the pulp chamber can be cleaned
- To enable root canals to be located and instrumented by providing straight-line access to the apical third of the root canals. (The initial cavity may be modified to achieve this objective)
- To enable a temporary seal to be placed. That is, the cavity provides sufficient retention for the temporary restoration as well as preserving enough bulk of tooth structure to sustain occlusal functional loading during the inter-appointment period
- To conserve as much sound tooth tissue as possible compatible with the above objectives.
- Essay: Detailed steps of performing RCT on a lower first molar in a single visit (14m)
page 70
A middle aged man requesting treatment for his upper front teeth, with history of allergy to antibiotics Periapical radiograph: apical radiolucency at 11
Intra-oral photographs:
- 11MB fractured (Class IV), restored with pin retained composite resin, white spot lesion and caries on 11B
- 21B Class V composite discolored, with stained margin
List five findings based on the radiograph and the intra oral photos provided. (5)
Describe how the root canals can be disinfected. (5)
- Chemo-mechanical instrumentation with medicaments
- Access cavity > using estimated working length for radicular access
- Hand or rotary file with anti-curvature filing
- Gates-glidden burs enlarge canal orifice
- Working length determination > apical instrumentation to full working length
- Canal shaping allow elimination of bacteria, infected dentine and facilitate irrigation
- Copious irrigation with sodium hypochlorite solution after each file instrumentation
- Disinfection, flushing debris, lubrication, dissolution of organic tissues
- Intra-canal medicaments
- Antimicrobial effect with CaOH, or anti-inflammatory & antimicrobial with Ledermix
- Seal with definitive restoration or double seal with cavit and IRM
37 deep amalgam MO restoration. Dull pain experienced after two weeks. Apical radiolucency and widen PDL space. (Formative, 2011)
a. How to protect the patients from the radiation for taking radiographs for endo? (suggest at least five ways) (5 marks)
Use of endoray and parallel technique (less error and distortion)
Use of apex locator to confirm working length prior taking radiograph
Ensure file inserted into canal is in correct position and able to have clear image by using at least # 15
file and place cotton pellet into canal to hold the file
Protection thyroid shield, lead apron
Choice of equipment like high speed F film, long cone, rectangular collimation to reduce radiation
exposure
Correct interpretation and diagnosis reduce unnecessary taking
37 deep amalgam MO restoration. Dull pain experienced after two weeks. Apical radiolucency and widen PDL space. (Formative, 2011)
b. Define chemo mechanical instrumentation in endodontics. (4 marks)
Cleaning of root canal system involve the combination of chemical action by irrigation and mechanical shaping action by hand or rotary filing, where 2 processes facilitate each other
Irrigation: flushing debris, lubricating, dissolving organic tissues, disinfection
Shaping: provide optimum shape for irrigation, cleaning, and obturation, remove debris, microorganism
and pulp tissues
37 deep amalgam MO restoration. Dull pain experienced after two weeks. Apical radiolucency and widen PDL space. (Formative, 2011)
c. Suggest at least four ways to prevent the pulp from being minimally infected prior to obturation (4 marks)
Keep canal dry with paper point before placing coronal restoration / obturation
Double seal with intracanal medicaments
Proper cleaning with instrument up to minimal acceptable MAF size and correct working length, with
copious irrigation and recapitulation
Intact coronal restoration without leakage
All procedures perform under rubber dam isolation and with other moisture control technique
Ensure periodontal condition is favorable (in perio-endo lesion with communication)
