Restorative/Endo/Periodontics

Question 1

Two periapical radiographs show lower anteriors 42, 41, 31, 32 that have all been treated endodontically with posts and cores. There is radiolucencies in all of the teeth affected. The patient is referred to you for periradicular surgery.

Name 3 tx options other than periradicular surgery

Answer 1

Attempt orthograde re-treatment
XLA
Monitor

Question 2

What is 2 criteria for Valid consent?

Answer 2

Must be voluntary
Must be informed

(Added extras)
- Must not be coerced
- Must have capacity

Question 3

Name 6 other things that you should tell the patient for valid consent.

Answer 3

• options for tx, risks and potential benefits
• Why you think a particular tx is necessary and appropriate for them
• Consequences, risks and benefits of the tx you propose
• Likely Prognosis
• Your recommended option
• Cost
• Risks of no tx
• Guarantee of tx; how long for?

Question 4

ENDO - Name 4 and explain, stainless steel file mishaps/faults

Answer 4

• Ledges: Ledge is internal transportation of the canal which occurs when working
  short of the length and are difficult to bypass
• Canal Blockage:

Question 5

Describe the endodontic process including calculating working length until the obturation stage

Answer 5

• Coronal access to the root canal system after taking Pre-op PA radiographs, using rubber dam and LA
• Remove all caries and defective restorations from the crownAllows assessment of restorability and creates an environment suitable for obtaining adequate isolationRoot canal system instrumentation and preparation and irrigation with Sodium hypochlorite using the ProTaper technique
  Obturation of the root canal system with GP size matched cones
  Coronal sealFinal restoration

Question 6

Patient attends with intention of an amalgam restoration

What are the benefits of copper enriched amalgam?

Answer 6

Copper increases the strength and hardness of the amalgam material

Copper enriched products and the non-y2 amalgam are high in copper, which gives higher early strength before 24-hour mark, less creep, higher corrosion resistance and increased durability of the margins.

Question 7

What is the function of zinc in amalgam?

Answer 7

Zinc is the scavenger molecule during production of amalgam, which
preferentially oxidises and forms slag.

Zinc is no longer incorporated as it reacts with water and causes a poor marginal seal

Question 8

How is copper enriched amalgam made?

Answer 8

High copper admixed alloy procedure is made by adding silver-copper eutectic particles to silver-tin lathe cut particles to produce high copper y-2 free amalgam.

Question 9

What is creep?

Answer 9

Creep is the slow internal stressing and deformation of amalgam under stress as the material can be repeatedly stressed for long periods at low stress levels.

Question 10

What are the main symptoms of creep?

Answer 10

Ditching of the restoration margins, which can result in fracturing of the margins causing microleakage and thus secondary caries.
Microleakage can cause pulpal irritation, infection, discolouration and secondary caries under the restoration.

Question 11

You are shown a cast with an upper Co/Cr framework in place.

What areas on the upper and lower that give tooth borne support

Answer 11

Upper = hard palate and residual ridge
Lower = buccal shelf, residual ridge and retro-molar pad

Question 12

Define Kennedy classifications

Answer 12

It is an anatomical classification that describes the number and distribution of edentulous areas present.

Class I = bilateral free end saddle
Class II = unilateral free end saddle
Class III = unilateral bounded saddle
Class IV = anterior bounded (crossing the midline)

Question 13

What function does the palatal extension provide?

Answer 13

It provides increased mucosal support as a larger surface area is covered which can create a greater seal.

Question 14

Why do we place rest seats (present on 12)?

Answer 14

It provides bracing on anterior teeth and indirect retention

Question 15

Why would a rest seat be placed on the 16?

Answer 15

To provide direct retentive elements to work in a planned manner and

reciprocation further more offering further support by preventing the movement of the RPD towards the mucosa.
Rest seats can be used for bracing and reciprocation

Question 16

What are the different types of clasps for premolars?

Answer 16

Gingivally approaching I-bar clasp

Question 17

What are the different types of clasps for molars?

Answer 17

Occlusally approaching single arm clasp

Occlusally approaching circumferential clasp

Occlusally approaching ring clasp

Question 18

Why would framework not extend to the anteriors and gingival margin clearance and what is the benefit of not doing this?

Answer 18

Less mucosal coverage, making it easier to clean the gingival tissues, less irritation and better compliance.

Question 19

Two Impression trays are given one with green stick on posterior saddles and one with Impression taken in alginate.
What impression materials are used for primary impressions in complete denture cases?

Answer 19

Impression compound which is a non-elastic impression material

Alginate which is an elastic irreversible hydrocolloid impression material

Question 20

What are the constituents of alginate and green stick?

Answer 20

Alginate – calcium sulphate, zinc oxide, sodium phosphate
Green stick – carnauba wax, talc, stearic acid

Question 21

Why would a tooth have Impression compound placed on it?

Answer 21

You can record a single tooth crown preparation using green stick and the copper ring technique

Question 22

A patient attends with a fractured 26 MOD amalgam which has also been root treated.
What are the restorative options for this tooth?

Answer 22

Onlay with cuspal coverage
MCC/GSC
indirect restoration

Question 23

The GP has been exposed for 6 months; what is your new treatment plan and why?

Answer 23

Requires to be re-root treated when the root has been exposed to the oral environment for more than 3 months as it puts the tooth at risk of bacterial invasion.

Question 24

What are the features of Nayyar core?

Answer 24

Retention obtained from the undercuts in the divergent canals and pulp chamber

2-4mm of Gp removed from the canal and replaced with amalgam

Immediate placement and coronal preparation can be done at the same appointment

Question 25

Name 2 restorative materials in dentistry that can bond amalgam to tooth?

Answer 25

RMGIC

GI

Question 26

Which bond strength is stronger, amalgam or composite?
Composite

Answer 26

Composite - Amalgam doesn’t bond to tooth

Question 27

A patient attends with a space between 13 and 14

What investigations should you do and why?

Answer 27

BPE – screening tool for periodontal health status

MPBS – to assess plaque and bleeding levels with BPE >1

6 point pocket chart – to assess periodontal disease, true pocketing, gingival recession and mobility when BPE scores >3

Periapical radiographs to assess bone levels, prognosis of the teeth, any radiolucencies

Study models to monitor change over time

Question 28

Other than aesthetics, why would restoring this space be challenging? (space between 13-14)

Answer 28

The space is relatively small and if the teeth are of good prognosis you would be reluctant to remove healthy tooth tissue and place veneers or crowns.

Composite could be used to make either the 13 or 14 bigger to help close the gap but this may be more noticeable to a patient and others.

Question 29

What problems are associated with implant placement in this case?

Answer 29

Inadequate space available – requires 7mm
Inadequate bone levels due to periodontal disease
Current uncontrolled periodontal disease

Question 30

Patient attends with attrition and erosion.

What are the different types of tooth wear?

Answer 30

Attrition – physiological wearing away of tooth structure as a result of tooth to
tooth contact e.g. bruxism
Abrasion – physical wear of tooth substance through an abnormal mechanical process independent of occlusion e.g. toothbrushing
Erosion – loss of tooth surface by chemical process that does not involve bacterial action e.g. acidic drinks, GORD
Abfraction – loss of hard tissue from eccentric occlusal forces leading to compressive and tensile stresses at the cervical fulcrum areas of the tooth.

Question 31

What are the BEWE scores?

Answer 31

0 = no erosive wear
1= initial loss of surface texture
2 = distinct defect hard tissue loss <50% of surface
3 = hard tissue loss >50% of the surface area

Add up scores for all sextant and then risk assess
None = <2

Low = 3-8
Medium 9-13

High = >14

Question 32

Name 3 routes or ways in which teeth can be desensitised?

Answer 32

Duraphat fluoride varnish
Prime and bond to protect surfaces

Sensodyne/Colgate relief toothpaste

Question 33

What is the DAHL technique?

Answer 33

It is a technique used to gain inter-occlusal space in cases of localised tooth wear without tooth reduction over a period of 3-6 months allowing for dento-alveolar compensation.
An appliance such as a composite platform is placed anteriorly to increase the OVD by 2-3mm and over time the posterior teeth erupt into occlusion and the anteriors are intruded.
This creates space to allow restorations of the anterior teeth without further tooth reduction.

Question 34

List 4 contraindicated groups for using Dahl on

Answer 34

Patients with active periodontal disease

Patients with TMJ problems

Post orthodontic treatment
Patients taking bisphosphonates

If dental implants exist

Question 35

Name 4 constituents of composite and give an example for each constituent

Answer 35

Resin – Bis-GMA

Glass – silica or quartz

Low weight dimethacrylate – TEGDMA

Light activator – camphorquinone

Silane coupling agent – bifunctional molecule binding resin and filler

Question 36

On a cervical abrasion cavity why would you use RMGI instead of composite resin?

Answer 36

Due to poor moisture control at the cervical region, meaning composite would fail. RMGIC has less polymerisation shrinkage and is best suited for cervical abrasion lesions where moisture cannot be controlled.