Obturation

Question 1

What is the aim of obturation?

Answer 1

Seal the cleaned, shaped and disinfected RCS with an inert biocompatible filling and to prevent reinfection

Question 2

Name 2 objectives of obturation

Answer 2

1. Prevent any residual contamination within RCS entering the periapical tissues
2. Prevent recontamination of the RCS via the oral cavity

Question 3

Name 6 ideal properties of a core filling material

Answer 3

1. Easily introduced into RCS and not shrink on insertion
2. Seal canal laterally and apically
3. Bacteriostatic
4. Radio-opaque
5. Insoluble in tissue fluids
6. Should not stain or irritate tissues

Question 4

Name 6 ideal properties of a sealer

Answer 4

1. Should exhibit tackiness when mixed to provide good adhesion to canal when set
2. Radio-opaque
3. Not shrink on setting
4. Bacteriostatic
5. Should not stain or irritate tooth structures and tissues
6. Soluble in common solvent if necessary to remove it

Question 5

What is the core material of choice?

Answer 5

Gutta-Percha

Question 6

What 4 components make up GP?

Answer 6

1. Inert rubber material incorporated with zinc oxide
2. Waxes
3. Metal salts
4. Colouring agents

Question 7

Name 3 root canal sealers

Answer 7

1. Zinc Oxide Eugenol (Tubliseal)
2. Calcium Hydroxide (Apexit)
3. Resin based (AH Plus)

Question 8

Describe 3 classifications of bioceramics

Answer 8

Bioinert - Non-interactive with biological systems
Bioactive - Durable tissues which undergo interfacial interactions with surrounding tissues
Biodegradable - Soluble which are eventually replaced or incorporated into tissue

Question 9

Describe the classification of bioceramic sealers

Answer 9

• Contain calcium silicate so are bioactive

- Chemically bonds to dentine with hydroxyapatite formation and does not cause inflammation apically

Question 10

Name 6 properties of bioceramic sealers

Answer 10

1. Biocompatible and osteogenic
2. Chemical bond of sealer to dentine
3. Highly radio-opaque
4. Hydrophilic
5. User friendly
6. Highly antimicrobial

Question 11

What is the major drawback of bioceramics?

Answer 11

Can be difficult to remove for re-RCT

Question 12

Name 6 methods of obturation

Answer 12

1. Single point
2. Cold lateral condensation
3. Warm lateral compaction
4. Warm vertical compaction
5. Carrier based techniques
6. Apical barrier (bioactive MTA)

Question 13

Describe the process of the insertion of master GP into a root canal

Answer 13

• Select master GP to match finishing file
• Insert MGP to full WL, check for tug-back and can take trial radiograph to ensure going to WL
• Dry canal with paper points
• Coat MGP in sealer and carry into canal to full WL

Question 14

Describe the process of filling canal using finger spreaders

Answer 14

• Finger spreader placed alongside MGP in canal
• Select accessory point and coat with sealer and insert in the canal immediately following spreader withdrawal
• Repeat sequence using larger spreaders and AGP until coronal third of canal is filled

Question 15

What is the final step of cold lateral condensation following insertion of AGP?

Answer 15

Remove excess GP from canal orifice with heater excavator and firmly compact remaining GP in orifice

Question 16

Describe 4 components of a successful obturation

Answer 16

1. Entire WL obturated
2. No voids in filling
3. No overfilling into peri-radicular tissues
4. Matches original tooth morphology

Question 17

What is the most common method of evaluating an obturation?

Answer 17

Radiographic assessment

Question 18

Describe 3 criteria of radiographic assessment of obturation

Answer 18

Length - Will be at prepared WL (~1m from apex)
Density - Radiographic appearance of dense homogenous three dimension obturation without voids
Shape - Reflect the shape of the preparation i.e tapered

Question 19

Name 2 important aspects of a coronal seal

Answer 19

1. Coverage of GP points

2. Cuspal protection (molars and premolars)

Question 20

Name 2 common coronal seals

Answer 20

1. RMGI Cement (Vitrbond)

2. Smart Dentine Replacement (SDR)

Question 21

When is vitrbond placed?

Answer 21

Thin layer placed on floor of the pulp chamber to seal root filling prior to placement of final restoration

Question 22

Describe how SDR works as a coronal seal

Answer 22

• SDR is bulk-fill flowable composite base in 4mm increments
• Etch and bond is placed SDR is applied up to 4mm over root filling
• Remove tubliseal from cavity walls as contains eugenol which will affect bond
• 2mm left on top for capping layer of universal composite material