2021 MSA Part 2

Question 1

What collimating error has occurred when there is incorrect alignment between the X-ray tube and receptor holder?

Answer 1

Cone cutting

Question 2

What faults in the placement of an amalgam restoration can lead to overhangs? (2 marks)

Answer 2

Too much force when condensing amalgam
Poor adaptation of the matrix band

Question 3

What problems can amalgam overhangs give rise to in the short term and long term?

Answer 3

Short term:
- food trap
- difficulty in cleaning
Long term:
- secondary caries
- periodontal disease

Question 4

List two ways to correct an amalgam overhang

Answer 4

Polishing using a finishing bur
Replacement of the restoration

Question 5

What further investigations can be carried out in a patient with a necrotising periodontal disease?

Answer 5

Radiographs to determine if there is any bone loss

Question 6

Give 3 disposing factors of necrotising periodontal disease

Answer 6

Any 3 from:
Psychological stress
Poor OH
Lack of sleep
Smoking
Immunosuppression
Malnutrition

Question 7

What are the risks of no tx in necrotising periodontal disease?

Answer 7

Tooth loss due to rapid bone destruction

Question 8

What tx is provided on the first visit for necrotising periodontal disease? (3 marks)

Answer 8

Ultrasonic debridement
0.2% chlorhexidine mouth wash twice daily
OHI - don’t brush until acute symptoms subside

Question 9

What antibiotic and dosage should be prescribed for acute tx of necrotising periodontal disease and for how long should the patient take it?

Answer 9

Metronidazole - 400mg 3 times daily for 3 days

Question 10

When should a necrotising periodontal disease patient be seen for review after tx of initial symptoms?

Answer 10

1-2 weeks

Question 11

What is the distance between the mandible at rest and in ICP called?

Answer 11

The freeway space

Question 12

What is the average distance of the freeway space?

Answer 12

2-4mm

Question 13

The mandible is said to be on its retruded axis when it occupies any position between what points?

Answer 13

Retruded axis position and retruded contact position

Question 14

What is a border position of the mandible?

Answer 14

Mandibular position determined by the anatomy of the TMJ of and its musculature

Question 15

Why is the retruded axis important in clinical dentistry?

Answer 15

It is a reproducible jaw position

Question 16

What two records are required for mounting casts on a semi adjustable or average value articulator?

Answer 16

The relationship of the maxilla to the hinge axis of rotation of the mandible
An interocclusal registration

Question 17

What is the average value of the sagittal condylar guidance angle which may be used on an articulator?

Answer 17

30º

Question 18

Name the design principles outlined by Herbert Schilder

Answer 18

Create a continuous tapering funnel
Maintain apical foramen in the original position
Keep apical opening as small as possible

Question 19

Besides disinfection of the root canal space, name two other objectives or irrigant use in root canal treatment

Answer 19

Lubrication of the root canal space
Removal of debris

Question 20

What is the ideal primary endodontic irrigant and at what concentration range is it most effective?

Answer 20

Sodium hypochlorite
Between 0.5 and 6%

Question 21

Name three factors important for the function Sodium Hypochlorite

Answer 21

Concentration
Volume
Contact time with root canal walls

Question 22

What are the two main differences in composition between decorative and dental ceramic?

Answer 22

Decorative ceramics contain more Kaolin
Dental ceramics contain more feldspar

Question 23

What does translucency mean with regard to optical properties of a material?

Answer 23

The ability of a material to allow light to pass through but be scattered at one of the surfaces or internally leading to a blurring of the transmitted light

Question 24

What does opalescence mean with regard to optical properties of a material?

Answer 24

A materials ability to reflect, scatter and refract light

Question 25

How can ceramic surfaces be modified to make it more retentive prior to using silane?

Answer 25

Acid etch with hydrofluoric acid

Question 26

Chemically how does a silane coupling agent work when bonding composite to ceramic?

Answer 26

C=C bonds on one side of silane react with the composite Oxides groups on other side of silane form strong bonds with the porcelain

Question 27

What is the most common cause of facial trauma in a female patient

Answer 27

Physical abuse

Question 28

Aside from physical violence list four other forms of abuse that might be involved in domestic abuse?

Answer 28

Verbal Emotional Sexual Financial

Question 29

What process should you follow to ask about the possibility of domestic abuse and briefly describe? (4 marks)

Answer 29

AVDR Ask Validate Document Refer

Question 30

List four physical signs you might see in domestic abuse

Answer 30

Repeated injuries Bruises at different stages of healing TMJ problems Strangle marks around the neck

Question 31

List two categories of patient who may be considered to be more at risk in terms of domestic abuse than others

Answer 31

Women who are separated Those with mental health problems

Question 32

List four benefits that digital radiography has over film radiography

Answer 32

No need for chemical processing Easy storage of images Easy back up of images Images can be integrated into digital patient records

Question 33

What is the benefit of using rectangular collimation? (2 marks)

Answer 33

It can reduce effective dose to the patient by approximately 50%

Question 34

What chemical property of lead makes it particularly effective at absorbing X-ray photons?

Answer 34

It’s high atomic number

Question 35

What is the minimum distance it is recommended a dentist stands away from the X-ray source?

Answer 35

1.5m

Question 36

What does the term justification mean in the context of decision whether or not to take a dental radiograph?

Answer 36

Taking the radiograph must have sufficient benefit to the individual in order to offset the detriment

Question 37

What does ALARP stand for?

Answer 37

As low as reasonably practical

Question 38

Name two characteristics of biofilm ECM that confers resistance from antimicrobial agents

Answer 38

Biofilms produce an LPS protective barrier Biofilms impair diffusion of antimicrobials

Question 39

Name two important bacteria clearly implicated in periodontal disease, based on Socransky’s red disease complex

Answer 39

P. gingivalis T. forsythia

Question 40

Name two bacteria associated with caries development

Answer 40

S. mutans A.a.

Question 41

What two key features enable cariogenic organisms to stick to enamel surfaces and autoaggregate, and to survive within an acidic environment?

Answer 41

Glucans - attach to enamel ATPase - controls the pH

Question 42

Name two systemic diseases that have been shown to be associated with periodontal biofilms

Answer 42

Cardiovascular disease Diabetes mellitus

Question 43

In the correct order, what are the 5 core stages of the washer-disinfect or cycle and what are their functions?

Answer 43

Pre wash - removes gross contamination Main wash - detergent is added to remove biological matter Rinse - removes residual contamination Thermal disinfection - actively kills microorganisms with heated water Drying - uses hot air to remove moisture

Question 44

What does PICO stand for?

Answer 44

Population Intervention Comparison Outcome