2021 MSA Part 2 Flashcards
What collimating error has occurred when there is incorrect alignment between the X-ray tube and receptor holder?
Cone cutting
What faults in the placement of an amalgam restoration can lead to overhangs? (2 marks)
Too much force when condensing amalgam
Poor adaptation of the matrix band
What problems can amalgam overhangs give rise to in the short term and long term?
Short term:
- food trap
- difficulty in cleaning
Long term:
- secondary caries
- periodontal disease
List two ways to correct an amalgam overhang
Polishing using a finishing bur
Replacement of the restoration
What further investigations can be carried out in a patient with a necrotising periodontal disease?
Radiographs to determine if there is any bone loss
Give 3 disposing factors of necrotising periodontal disease
Any 3 from:
Psychological stress
Poor OH
Lack of sleep
Smoking
Immunosuppression
Malnutrition
What are the risks of no tx in necrotising periodontal disease?
Tooth loss due to rapid bone destruction
What tx is provided on the first visit for necrotising periodontal disease? (3 marks)
Ultrasonic debridement
0.2% chlorhexidine mouth wash twice daily
OHI - don’t brush until acute symptoms subside
What antibiotic and dosage should be prescribed for acute tx of necrotising periodontal disease and for how long should the patient take it?
Metronidazole - 400mg 3 times daily for 3 days
When should a necrotising periodontal disease patient be seen for review after tx of initial symptoms?
1-2 weeks
What is the distance between the mandible at rest and in ICP called?
The freeway space
What is the average distance of the freeway space?
2-4mm
The mandible is said to be on its retruded axis when it occupies any position between what points?
Retruded axis position and retruded contact position
What is a border position of the mandible?
Mandibular position determined by the anatomy of the TMJ of and its musculature
Why is the retruded axis important in clinical dentistry?
It is a reproducible jaw position
What two records are required for mounting casts on a semi adjustable or average value articulator?
The relationship of the maxilla to the hinge axis of rotation of the mandible
An interocclusal registration
What is the average value of the sagittal condylar guidance angle which may be used on an articulator?
30º
Name the design principles outlined by Herbert Schilder
Create a continuous tapering funnel
Maintain apical foramen in the original position
Keep apical opening as small as possible
Besides disinfection of the root canal space, name two other objectives or irrigant use in root canal treatment
Lubrication of the root canal space
Removal of debris
What is the ideal primary endodontic irrigant and at what concentration range is it most effective?
Sodium hypochlorite
Between 0.5 and 6%
Name three factors important for the function Sodium Hypochlorite
Concentration
Volume
Contact time with root canal walls
What are the two main differences in composition between decorative and dental ceramic?
Decorative ceramics contain more Kaolin
Dental ceramics contain more feldspar
What does translucency mean with regard to optical properties of a material?
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
What does opalescence mean with regard to optical properties of a material?
A materials ability to reflect, scatter and refract light