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42 Cards in this Set
- Front
- Back
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Which muscles depress the mandible?
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Digastric, mylohyoid, geniohyoid (+ gravity)
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Which muscles raise the mandible?
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Temporalis, Medial Pterygoid, Masseter
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Which musles protrude the mandible?
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Lateral Pterygoid assisted my the medial pterygoid
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Which muscle retract the mandible?
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Posterior fibres of the Temporalis, Deep part of Masseter, Geniohyoid and Digastric
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What is the function of the Masseter?
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Raise/retract the mandible, grinding, clenching
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What is the function of the Temporalis?
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Close teeth, biting, retraction/raise mandible
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What are the extracapsular ligaments of the TMJ?
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Stylomandibular
Sphenomadibular Lateral |
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What is the function of the lateral Pterygoid?
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Superior head protrudes the mandible
Inferior head lateral extrusion |
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What is the function of the medial Pterygoid?
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Raise the mandible, lateral movement whilst chewing
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Which cranial nerves are responsible for taste?
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7, 9 and 10
(Facial, Glossopharyngeal and Vagus) |
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Which cranial nerves are responsible for tongue sensation?
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Anterior 2/3's 5th (Trigeminal)
Posterior 1/3 9th (Glossopharyngeal) |
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Which cranial nerve controls the muscles of mastication?
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5th - Trigeminal
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Minor salivary glands are found everywhere except? How many are there?
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The hard palate and gingiva. 600-1000
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Describe appropriate facial symetry lines
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Facial midline and pupillary midline should divide face into equal quarters.
Hairline to eyebrows/ eyebrows to just under nose/ under nose to chin All should be approximately equal (uppper/middle/lower facial height) |
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What are the 3 facial types?
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Mesofacial (normal/round)
Brachyfacial (compressed) Dolicofacial (elongated) |
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Describe a Class I normal occlusion
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Normal overbite/overjet (2mm)
No inappropriate rotations/angulations Class I molars/canines (mandibular teeth half tooth infront) No tight contacts or diastema |
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Describe a Class II occlusion
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Maxiallary molars infront of mandibular molars, overbite
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Describe a Class II occlusion
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Mandibular far infront of maxillary molars, underbit
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An occlusion can be classified as Class I (or II or III) MALocclusion when...
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crowding, openbite, deepbite, crossbite
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What is the difference between Orthopaedics and Orthodontics
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Orthopaedics - correction of jaw discrepencies and malrelationships
Orthodontics - correction of dental malocclusions |
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What does a facebow do?
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Record the relationship of the maxilla to the hinge axis of the condyles for transferance to an articular
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What are the points of reference for the facebow?
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TMJ is approximately 12mm long the line from Tragus to outer canthus of the eye.
3rd point of reference - 43mm superior from incisal edge of maxillary incisors |
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What is the MMR and what is is for?
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Maxilla/mandible record, taken in wax to help position the mandible in the articulator
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What is in dental alginate?
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Denal alginate is primarily a salt of Alginic Acid- a natural polysaccharide extracted from marine algae
Activators (eg Calcium sulphate dihydrate) are a source of Ca for the setting reaction Retarders (eg sodium phosphate) can be added to slow down the setting reaction. These remove Ca ions from solution so they can't participate in polymerisation Fillers such as zinc oxide and diatomaceous earth Flavours, colours, disinfectants, indicator |
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What is the setting reaction of dental alginate?
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The additon of water makes a flowable solution. The cross linking/polymerisaton of alginic acid with calcium forms a flexible gel
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What are the pros of alginate?
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Cheap
Easy to use Hydrophillic (therefore flows in mouth) Relatively pleasant taste/odor Non toxic |
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What are the cons of alginate?
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Low strength (resistance to tear)
Unstable therefore loss of accuracy (dehydrates when humidity below 100%, gains water when over 100%, syneresis - continued polymerisation therefore shrinkage) Plastic deformation (therefore must be removed quickly ie with jerk action) Can only be poured once |
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Describe the clinical handling of a completed alginate impression.
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As there is an initial expansion (first 20 minutes) followed by slow contraction, best to pour impression after 20 minutes and before an hour
The impression should be stored in a humidifier (ie in a bag with a damp cloth) but not in water |
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Describe techniques in taking an alginate impression
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First select size of tray and prepare it.
Mix the recommended amounts together within 30 seconds To avoid palatal air bubbles place a scoop of alginate on the palate first with a finger For maxilla, stand behind patient, rotate into mouth then place posterior first For mandible, stand infront of patien, place anterior first, then lift tongue, then place posterior Alginate flows best under stress so seat with a jolt To avoid tearing, break seal and remove with a jerk Check for adherence to tray, air bubbles, all relevant anatomy |
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What is the SDH policy on disinfecting impressions?
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Rinse off blood/saliva
2 minutes in miltons To lab in clear plastic bag |
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What are the 3 main gypsum products, there colour and use?
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Dental Plaster - white, weakest, cheap, used to mount stone impressions to articulators, large particle size (made in kiln)
Dental Stone - yellow, high strength, most used for general purpose study models, moderately priced (made in autoclave) Die Stone - pink, strongest, costly, used to make models for production of metal/chrome oral devices, smallest particle size (densest) |
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How much water is needed for 100 grams of Dental plaster, Dental Stone and Die Stone?
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Dental plaster - 50-55ml
Dental stone - 30-33ml Die stone - 22-35ml |
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How is an impression poured and made into a model?
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Using the 2 pour method:
Usually done with dental stone. Impression is rinsed, excess water removed, place impression on vibrator, pour small amount of dental stone at one end and let in spread through to the other side covering all surfaces. Now add dental stone from the other end, letting it spread untill full. Remove air bubbles from surface as they appear. With left over plaster in bowl, wait till it is slightly set (stackable) and form a base on the table. Place the poured impression upside down on top. Wait 1 hour/untill reaction has stopped (reaches room temp) before removing the impression. Check for air bubbles. |
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When trimming, what demensions are required?
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11-13mm at its thinnest, flat, base parallel to ridges.
Land area should be 3-4mm wide and no more than 2mm above depth of sulcus |
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Describe the setting reaction of gypsums?
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The setting reaction is the reverse of its production. On addition of water the hemi-hydrate is converted to a dihydrate (exothermic) and then crystals precipitate.
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What are the constituants of gypsums (include it's production)?
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CaSO4.2H20 (dihydrate) is dehydrated to CaSO4.1/2H20 (hemi-hydrate) in production.
In addition to hemi-hydrate CaSO4 there are additives: K2SO4 activator improves the himi-hydrates solubility Borax inhibitor coats the crystals therefore decreasing solubility |
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What are the 4 kinds of mouthguards?
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1. Stock
2. Boil and Bite 3. Custom single layer vacuum 4. Custom multilayer pressure using drufosoft |
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What is a luxation injury? Prefixes?
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Movement of tooth in socket.
Concussion = no bleeding Sub = bleeding Lateral = distinct movement Avulsion = tooth loss Intrusion = upwards Extrusion = outwards |
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What are some anatomical features that put people at risk?
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Mal 3 occlusion
Incompetent lips Shallow sulcus depth Missing/unerupted teeth Short teeth Caries |
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What sports are highest risk?
How likely is injuring the same tooth again? How likely is it that an adjacent tooth is effected? What age group is trauma most commen? In over 22's what are the main causes of trauma? |
Football, Cycling, Soccer
1 in 3 chance reinjury 15% chance adjacent tooth effected 14 year olds Accident, assault |
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What are the 5 rules of treating trauma?
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Be a master of pain control
Be compassionate Be willing to be on call Keep accurate records Be a heeler not a mechanic Also review regularly |
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What are the 2 techniques for taking an impression?
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Mucostatic
eg low density alginate. Records undisplaced tissues. When under force load distribution will be uneven. However retention will be excellent due to close association with mucosa Mucocompressive eg with high density alginates. Gives impression when tissues under load, therefore better load distribution in dentures. However when not under load retention may be compromised. |
