Restorative/Endo/Perio

Question 1

2 PA’s show 41,42,31,32 all treated endo w posts/cores. Radiolucencies in all teeth affected, pt is referred to you for periradicular surgery, name 3 other treatment options.

Answer 1

Attempt orthograde re-treatment
XLA
Monitor

Question 2

What are two criteria for valid consent?

Answer 2

It must be voluntary
It must be informed

Question 3

Name 6 things you should tell the patient to gain valid consent

Answer 3

Options for treatment, their risks and benefits
Why you think a particular treatment is necessary and appropriate
The consequences, risks and benefits of the treatment you propose
The likely prognosis
Your recommended option
The cost of proposed treatment
What might happen if the proposed treatment isnt carried out
Whether the treatment is guaranteed, how long it is guaranteed for and any exclusions that apply

Question 4

Name 4 and explain stainless steel file mishaps/faults that may occur during canal preparation.

Answer 4

Ledges - internal transportation of the canal which occurs when working short of the length and are difficult to bypass
Canal blockage - cause by dentine debris getting packed into apical portion of the root
Instrument separation - too much pressure on use of instrument
Apical zipping/Transportation of the foramen - occurs as a result of the tendency of an instrument to straighten in a curved canal, results in a tear-drop shaped canal

Question 5

What are the benefits of copper enriched amalgam?

Answer 5

Copper increases strength and hardness

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

Question 6

What is the function of zinc in amalgam?

Answer 6

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

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

Question 7

How is copper enriched amalgam made?

Answer 7

Silver-copper eutetic particles added to silver-tin particles

Produce high copper y-2 free amalgam

Question 8

Explain the process of delayed expansion in relation to DMS

Answer 8

Alloys containing zinc, if contaminated with moisture during trituration (production of homogenous material) or condensation results in a large expansion occurring. t

Question 9

Explain the process of delayed expansion in relation to DMS

Answer 9

Alloys containing zinc, if contaminated with moisture during trituration (production of homogenous material) or condensation results in a large expansion occurring. This is due to the release of hydrogen gas which raises internal pressure.

Expansion leading to increased pressure can cause pressure on the pulp causing pain, high points leading to occlusal interferences, greater susceptibility to corrosion and expansion over the cavity margins increasing likelihood of fractures.

Question 10

What is creep in relation to amalgam restorations?

Answer 10

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 11

What are the main symptoms of creep?

Answer 11

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 12

You are shown a cast with upper Co/Cr framework in place.
What areas on the upper/lower give tooth borne support?

Answer 12

Upper = Hard palate, residual ridge

Lower = Buccal shelf, residual ridge and retromolar pad

Question 13

Define Kennedy Classifications

Answer 13

Anatomical classification that describes the number and location of edentulous areas present

Class 1 - bilateral free end saddle
Class 2 - unilateral free end saddle
Class 3 - unilateral bounded saddle
Class 4 - anterior bounded saddle (crossing the midline)

Question 14

What function does the palatal extension of a denture provide?

Answer 14

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

Question 15

Why would we place a rest seat on the 12 for an RPD?

Answer 15

It provides bracing on anterior teeth and indirect retention

Question 16

Why would a rest seat be placed on the 16 for an RPD?

Answer 16

To provide direct retentive elements to work in a planned manner and reciprocation offering further support by preventing the movement of the RPD towards the mucosa

Rest seats can be used for bracing and reciprocation

Question 17

What are the different types of clasps for premolars?

Answer 17

Gingivally approaching I-bar clasp

Question 18

What are the different types of clasps for molars?

Answer 18

Occlusally approaching single arm clasp
Occlusally approaching circumferential clasp
Occlusally approaching ring clasp

Question 19

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

Answer 19

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

Question 20

What impression materials are used for primary impressions in complete denture cases?

Answer 20

Alginate which is an elastic irreversible hydrocolloid impression material

Impression compound which is a non-elastic impression material

Question 21

What are the constituents of alginate and greenstick?

Answer 21

Alginate - calcium sulphate, zinc oxide, sodium phosphate

Green stick - Carnauba wax, talc, stearic acid

Question 22

Why would a tooth have impression compound placed on it?

Answer 22

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

Question 23

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

Answer 23

Onlay with Cuspal coverage

MCC/GSC (gold shell crown)

Indirect restoration

Question 24

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

Answer 24

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 25

What are features of Nayyar core?

Answer 25

Retention obtained from 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 appt

Question 26

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

Answer 26

RMGIC
GI

Question 27

Which bond strength is stronger, amalgam or composite?

Answer 27

Composite

Question 28

A patient attends with a space between 13 and 14, what investigations will you carry out and why?

Answer 28

BPE - screening tool for periodontal health status
PGI - to assess plaque and bleeding levels with BPE >1
6PPC - to assess periodontal disease when BPE >3
PA radiographs to assess bone levels, prognosis of the teeth, any radiolucencies
Study models to monitor change over time

Question 29

Other than aesthetics, why would restoring the space between a 13 and 14 be difficult?

Answer 29

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 the 14 bigger to help close the gap but this may be more noticeable to a patient and others

Question 30

What problems are associated with implant placement in a case where a patient has a space between 13/14 and has periodontal disease?

Answer 30

Inadequate space available - requires 7mm

Inadequate bone levels due to perio

Current uncontrolled periodontal disease

Question 31

What are the different types of tooth wear + explain?

Answer 31

Attrition - tooth-tooth
Erosion - chemical process that doesnt involve bacterial action
Abfraction - loss of hard tissue from eccentric occlusal forces leading to compressive and tensile stresses at the cervical fulcrum area of tooth
Abrasion - wear of tooth through abnormal mechanical process independent of occlusion e.g. toothbrushing

Question 32

What is BEWE and how is it used to risk assess?

Answer 32

Basic Erosive Wear Examination

0 - no erosive wear
1 - initial loss of surface texture
2 - distinct hard tissue loss <50% of surface
3 - Hard tissue loss >50%

Add up scores for all sextants and then assess risk
No risk = <2
Low = 3-8
Medium = 9-13
High = >14

Question 33

Name 3 ways teeth can be desensitised?

Answer 33

Duraphat fluoride varnish
Sensodyne/Colgate relief toothpaste
Prime and bond to protect surfaces

Question 34

What is the DAHL technique?

Answer 34

Used to gain inter-occlusal space in cases of localised tooth wear without tooth reduction over a period of 3-6months 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 posteiror teeth erupt into occlusion and the anteriors are intruded. This creates space to allow restorations of the anterior teeth without further tooth reduction

Question 35

List 4 groups of patients that the DAHL technique is contraindicated for?

Answer 35

Periodontitis patients
Patients with TMJ disorders
Post orthodontic treatment
Patients taking bisphosphonates
If dental implants exist

Question 36

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

Answer 36

Resin - Bis-GMA

Glass - Silica or Quartz

Low weight dimethacrylate - TEGDMA

Light activator - camphorquinone

Silane coupling agent - bifunctional molecule binding resin and filler

Question 37

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

Answer 37

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

Question 38

What is an RPI?

Answer 38

It is a stress relieving clasp system which is used in free end saddle designs to prevent stress on the last abutment tooth and can also provide reciprocation

Question 39

What are the different components of an RPI system?

Answer 39

R - Rest (occlusal) - mesial of the tooth, rounded on the impression surface

P - Proximal plate (adjacent to saddle) - guide surface of 2-3mm, undercut to permit movement

I - I-bar clasp (gingivally approaching) - greatest prominence of the tooth contour

Question 40

What is the mechanism of action of an RPI?

Answer 40

The rest mesially acts as an axis of rotation. As the proximal plate and I bar rotates downwards and mesially around the axis of rotation during occlusal load.

The I bar and proximal plate disengage from the tooth/undercuts, thus avoiding potentially traumatic torque.

Question 41

How would you identify vertical bone defects?

Answer 41

PA Radiographs
6PPC

Question 42

How do vertical bone defects (infrabony pockets) form?

Answer 42

Radius of destruction of plaque determines the pattern. It is approximately 1.5-2mm and if the interproximal bone is greater than this then the pattern is verticular/angular in nature.

Question 43

How are vertical bone defects classified?

Answer 43

Goldman HM and Cohen came up with the classification
1 wall defect
2 wall defect - heal better
3 wall defect - heal better