Year 2 Flashcards
4 basic components of dental anlog x-ray films?
Film base
Adhesive layer
Film emulsion (silver halide crystals in gelatin matrix)
Protective layer
What are the 5 basic sizes for intraoral film packets?
#0: child IOPA, BW #1: Adult ant IOPA, mixed dentition BW #2: Adult IOPA, BW, child occlusal #3: extralong BW #4: occlusal in adults
What is an intensifying screen?
Contains phosphors that emit visible light when struck with x-ray photons. Results in lowered patient doses but resolution is reduced.
What are the 2 types of digital image receptors?
Solid state (direct) PSP (semi-direct)
What are the angles and point of entries for maxillary teeth?
- Mx incisors : +50, tip of nose
- Mx canines: +50, ala of nose
- Mx premolars: +30, level of pupil & close to the ala tragus line
- Mx molars: +25, outer canthus of eye, over cheek and below zygoma
What are the angles and point of entries for mandibular teeth?
- Md incisors: -20, tip of chin
- Md canine: -20, 2cm D to tip of chin
- Md premolars: -15, level of pupil, 3cm above lower border of md
- Md molars: -5, level of outer canthus of eye, 3cm above lower border of md.
What is paralleling technique?
Film is parallel to long axis of tooth and x-ray tube is right angles to tooth and film
What are the steps of processing conventional films?
- Development
- Rinsing
- Fixing
- Washing
- Drying
What is the principle of panoramic radiography?
Reciprocal movement of an X-ray source and a image receptor around a central plane, called the image layer (focal trough).
- The object of interest is located in the image layer
- Objects in front or behind this image layer are blurred out
What are examples of double real images?
Produced by structures located in the midline (x-ray beam passes through it 2x).
- Hard palate
- Soft palate
- Hyoid bone
- Spine
Describe features of ghost image
- Opposite side
- Same shape
- Less distinct
- Larger
- Projected higher
What is the time-distance-shielding principle?
- Reduced exposure time
- Increased distance form source (as distance doubles, intensity reduces by factor of 4)
- Shielding using lead barriers
What is the flow rate for water coolant?
35-50mL/min
What salivary gland contributes the most?
Submandibular gland
What is a mucocele?
Pooling of saliva in damaged or obstructed minor salivary gland duct.
What is sialolithiasis?
Calcified or organic matter in parenchyma or ducts of salivary glands (infection, swelling, mealtime discomfort)
What is mumps?
Fever, malaise, trismus, gland swelling
Common in parotid gland
What is juvenile recurrent parotitis?
- Disease in children
- Uni or bilateral parotid swellings
- Pain, fever, redness of skin overlying gland
What is sjorgren’s syndrome?
- Chronic autoimmune disorder that causes dry eyes and mouth (affects all exocrine glands)
- Primary: no connective tissue disease
- Secondary: connective tissue disease or rheumatoid arthritis
What is sialosis?
Bilateral and painless enlargements of parotid glands
What is ectodermal dysplasia?
- Hair, glands, teeth, skin, nails affected
- Conical shaped teeth
What is amelogenesis imperfecta and the 3 types?
Alteration in enamel structure in absence of systemic disorder
- Hypoplastic (pin points)
- Hypomaturation (white capped enamel)
- Hypocalcification (brittle, chalky)
What is dentinogenesis imperfecta?
Disturbance in dentine in absence of systemic disorder
- Type I: assoc with osteogenesis imperfecta
- Type II: not assoc with osteogenesis imperfecta
- Type III: bradwine type
What is regional odonto-dysplasia?
- Small irregular crowns with rough surface
- Large pulp chamber
What are the stress bearing areas on mandibular edentulous ridge?
- Buccal shelves
- Retromolar pads
- Alveolar ridge
What are the stress bearing areas on maxillary edentulous ridge?
- Firm tuberosities
- Hard palate
- Alveolar ridge
- Rugae
What is combination syndrome?
- Anterior part of mx edentulous ridge becomes mobile and resilient as fibrous tissue replaces underlying bone.
- Over eruption of lower anterior teeth
- Resorption of md distal extension area
- Decreased VDO
- Hypertrophy of tissues in mx tuberosities
What medications cause gingival hyperplasia?
- Phenytoin
- Sodium valproate
- Cyclosporin A
What are modifiable vs non-modifiable risk factors for oral cancer?
- Non modifiable: age, ethnicity, SES
- Modifiable: smoking, alcohol consumption, diet, lifestyle, betel quid
How does cartilage grow?
- Hyperplasia
- Hypertrophy
- Extracellular material deposition
(cartilage does the growing and bone replaces it)
What are the 6 fontanelles?
- Anterior
- Posterior
- Sphenoid (paired)
- Mastoid (paired)
What is the growth mechanism of cranial base vs cranial vault?
- Cranial base: endochondral ossification
- Cranial vault: intramembranous ossification
Describe remodelling of maxilla
Maxilla is connected to cranial base so it moves forward until age of 7 when cranial base growth stops. After this, the maxilla moves forwards and downwards from intramembranous ossification at the sutures. There is resorption of the anterior surface of the maxilla.
Describe formation of mandible
There is condensation of mesenchyme around meckels cartilage. The meckels cartilage disintegrates and bone replaces it. The condylar head is the only part of the mandible that grows via endochondral ossification.
What are 1st and 2nd arch muscles?
- 1st arch: muscles of mastication (temporalis, masseter, medial and lateral pterygoid)- 5th nerve
- 2nd arch: muscles of facial expression (frontalis, occipitalis, buccinator, obicularis oris)- 7th nerve
Layers of scalp
- Skin
- Connective tissue (dense)
- Aponeurosis
- Loose connective tissue
- Periosteum
What layer does blood and pus collect in skull?
Loose connective tissue (dangerous as infection can spread intracranially through veins)
What are the 3 divisions of the trigeminal nerve?
- Ophthalmic
- Maxillary
- Mandibular
What nerve innervates the TMJ?
Mandibular nerve (auricular temporal branch)
What are the branches of the mandibular nerve?
- Lingual nerve
- Inferior alveolar nerve
- Nerve to mylohyoid
What 4 muscles are innervated with V3?
- Temporalis
- Medial and lateral pterygoid
- Masseter
What nerve provides innervation to the tongue?
- Anterior 2/3 general sense: lingual branch of V3
- Anterior 2/3 taste: chroda tympani
- Posterior 1/3 sense: glossopharyngeal
- Muscles: hypoglossal
What 5 blood vessels provide the skull with blood?
- Supratrochlear
- Supraorbital
- Superficial temporal
- Posterior auricular
- Occipital
Explain the importance of danger triangle of the face?
Area between root of nose and angles of mouth. Veins that drain this region are connected to cavernous sinus and valveless. If infection reaches this area, cavernous sinus thrombosis can occur (nerves III, IV, V1, V2 and internal carotid artery run through cavernous sinus and would be affected)
What are the branches of the facial nerve?
- Posterior auricular
- Temporal
- Zygomatic
- Buccal
- Marginal mandibular
- Cervical
Signs of bells palsy
- Droop on one side of face due to damage to facial nerve
- Loss of taste sensation to anterior ⅔ of tongue
What is the innervation of the intrinsic muscles of the tongue?
Hypoglossal nerve
What is the sensory supply of posterior ⅓ of tongue?
Glossopharyngeal nerve (IX)
What is the sensory supply to anterior ⅔ of tongue?
Temp pain: lingual nerve (V3)
Special: chorda tympani (runs with facial nerve)
What nerve is at risk of damage when there is a mandible fracture?
Hypoglossal (XII)- tongue will deviate to side of damage
What does the lingual artery supply?
- Sublingual and submandibular salivary glands
- Muscles of tongue
What is the danger zone for spread of infection through spaces?
Retropharyngeal space- infection can spread to superior mediastinum of thorax
What is Ludwig’s Angina?
Involves spread of infection from mandibular teeth to one space initially. If infection spreads to retropharyngeal space, oedema of larynx can cause complete respiratory obstruction
What is the difference between C-fibres and Aδ fibres?
C-fibres: fine, slow conducting non-myelinated nerves- dull burning pain. Associated with skin, deep tissue and organ systems.. Associated with skin (superficial)
Aδ fibres: fine, myelinated fibres, conduct more rapidly- sharp, well-localised pain
What are the 8 branches of the external carotid artery?
- Superior thyroid
- Ascending pharyngeal
- Lingual
- Facial
- Occipital
- Posterior auricular
- Maxillary
- Superficial temporal
What is the parotid gland innervated by?
IX
What does the maxillary artery supply?
Nasal cavity, lateral wall and roof of the oral cavity, muscles of mastication, all teeth and dura mater in cranial cavity.
What are the 3 parts of the maxillary artery?
- Mandibular
- Pterygoid
- Pterygopalatine
What are the maxillary teeth supplied by?
Pterygopalatine part of maxillary artery.
- Posterior superior alveolar arteries supply the molars.
- Whilst in infraorbital foramen, infraorbital artery gives off the middle and anterior superior arteries that supply the premolars and anterior teeth respectfully
What BP indicates it’s unsafe to proceed?
SBP: >180mmHg
DBP: >110mmHg
What is xerostomia vs salivary hypofunction?
Xerostomia: subjective feeling of oral dryness
Salivary hypofunction: reduced saliva flow
What medications are used for patients with arrythmias?
- Amiodarone
- NOACs
Best to not use adrenaline in these patients
What drugs interact with asthmatic patients?
Aspirin
NSAIDs
Opiates
Macrolides- can interact with theophylline
Sulphite drugs
What are drug interactions with epileptic medications?
- Antibiotics: erythromycins and metronidazole inhibit metabolism of anticonvulsants
- Azoles (anti-fungal): interactions with sodium valproate, phenytoin, carbamazepine
- NSAIDs: use with sodium valproate can exacerbate bleeding
What are oral considerations for parkinson’s disease?
- Decreased dexterity
- Levodopa can cause xerostomia, nausea, oral burning
- Poor denture retention
- Excess salivation
- Avoid use of adrenaline in pts taking MAOIs
What are the patterns of erosion from vomiting?
- Smoothened cupped occlusal/incisal lesions
- Concave buccal surfaces
- Palatal surfaces affected
- Smooth, shiny and generalised loss of anatomy
What are oral considerations of diabetes?
- Risk of hypoglycaemia
- Salivary dysfunction
- Glossitis (BMS)
- Candidosis
- Angular cheilitis
- Periodontal disease
- Give patients paracetamol or codeine rather than NSAIDs (esp renal impairment)
What patients should we avoid giving adrenaline?
- Patients with hyperthyroidism
- Patients taking MAOIs
What does lithium interact with?
NSAIDs
Metronidazole
Tetracyclines
Diazepam
When is the best timing for extracts in dialysis patients? Why?
Best time for exo on nondialysis day. (dialysis causes blood to clot and heparin is taken to prevent this )
What are the Kennedy classes?
- Class I: bilateral edentulous areas posterior to all remaining teeth
- Class II: unilateral edentulous area located posterior to all remaining teeth
- Class III: unilateral edentulous area bounded by ant and post natural teeth
- Class IV: single, bilateral edentulous area anterior to remaining teeth
What are requirement of a major conenctor?
- Rigidity
- Non-interference with tissues
- Avoid terminating on FGM, tori, frenum, movable soft palate
What is a single palatal strap used for?
Bilateral short span edentulous areas (Kennedy class III)
What is anterior-posterior palatal strap used for?
- Class II and IV (can be used for almost any mx partial denture design)
- Presence of tori
When is a palatal plate type connector used?
Class I (last remaining tooth being canine or 1st premolar)
When is lingual bar used?
- Simplest and most commonly used lower major connector
- Use when possible
- Most hygienic
- Most comfortable
- Needs min 7mm from FGM to FOM
When is a lingual plate used?
- If lingual vestibule <7mm
- Prominent lingual frenum or tori
- Anterior teeth perio compromised
- When all post teeth are to be replaced bilaterally
Don’t use when there is severe anterior crowding
What is stability, support and retention?
- Support: resistance to movement toward tissues/teeth (rest)
- Retention: resistance to removal from tissues/teeth
- Stability: resistance to movement in the horizontal plane
What undercutz are co-cr, gold and stainless steel clasps suited to?
Co-cr: 0.25mm
Gold: 0.5mm
Stainless steel: 0.75mm
When should stress-releasing direct retainers be used? What are some examples of clasps?
- Distal extension
- Abutment periodontally involved
- Extensive edentulous space
RPI, RPA and combination clasp
What is RPI?
Mesial rest, proximal plate, I-bar
(stops destructive forces on tooth)