wear and such Flashcards
Why may wear be repaired?
- aesthetic concerns
- symptoms of pain/discomfort
- unstable occlusion
- function difficulties
- excessive rate of tooth loss
How would you study the rate of tooth wear ?
photos
study models
measurements - taken at 6-12 month intervals
What are the 5 factors which should be taken into consideration for restoring wear are ?
- pattern of tooth loss
- inter-occlusal space
- space requirements for the restorations to be used
- the quality and quantity of the remaining hard tissue (especially the enamel)
- the aesthetic demands of the patient
What is the dahl technique ?
it is a means of gaining interocclusal space in localised looth wear and tooth reduction cases.
an anterior appliance is placed in order to allow for tooth eruption posteriorly to allow for an increase of 2-3mm in the OVD which allows for the restoration of the anteriors.
What are the various types of NCTSL?
- Attrition
- Abrasion
- Abfraction
- erosion
What are the characteristics of erosion?
loss of hard tissue due to chemical processes which does not involve bacteria. usually co-exsits with attrition and/or abrasion so differential diagnosis can become difficult,
What is the presentation of erosion?
transparent, thinned edges of the incisal edge
irregular occlusal plane
reduction in crown height
loss may not be uniform
What problems occur with erosion?
sensitivity
dental pain
loss of vitality
aesthetics
What is combination syndrome?
lower anterior teeth opposing upper edentulous ridge
instability Cu/- in function with the concentration of occulasal forces at the anterior
** consider extension of SDA
What is the concept of the shortened dental arch ?
anterior teeth which also have occluding premolars or molars with at least 3-5 occluding units should be present
1 unit - one pair of premolars
2 units one pair of molars
What are some examples of adhesive bridges?
resin retained bridge (RRB) resin bonded bridge (RBB) Maryland resin bonded fixed partial denture (RBFPD) minimal prep required
What are some examples of conventional bridges?
fixed-fixed bridge = abutment (pontic) abutment bridge with 2 crown preps
Cantilever - has crown or wing at one side only
Fixed movable bridge - ridged pointic (usually at the distal end ) and a more flexable connector at the othe r(mesial ) in order to allow for vertical movement.
What are the contraindications for bridgework ?
Uncooperative patient
Medical history contra-indications
Poor oral hygiene
High caries rate
Periodontal disease
Large pulps- for conventional bridges
High possibility of further tooth loss within arch
Prognosis of abutment poor
Length of span too great
Ridge form and tissue loss
Surface area of root insufficient
Tilting and rotation of teeth
Degree of restoration (how much of tooth is left after preparation)
Periapical status
Periodontal status (bone loss)
What are good indications for bridgework ?
Function and stability
Appearance
Speech
Psychological reasons
Systemic disease e.g. epileptics also if a implant is not able to be placed
Co-operative patient
Heavily restored teeth
Favourable abutment angulations
Favourable occlusion
What must be considered when evaluating abutments?
- must be able to withstand forces
- supporting tssue must be healthy and free of inflammation or pathology
- crown ratio must be minimum 1:1 ratio but with an noptimun of 2:3
- root surface area (antes law)
- perio status
What is antes law?
states that the root surface area of the abutment teeth shoul dbe equal or greater than that of the teeth being replaced
Why are cantilever bridges more successful anteriorly ?
due to their divergent path of insertion
What are the indicators for anterior cantilever bridges?
Young teeth
Good enamel quality
Large abutment surface area
Minimal occlusal load
Good for single tooth replacement
Contraindications for adhesive bridges?
Long spans
Soft or hard tissue loss
Heavy occlusal load such as bruxism or overeruption of opposing teeth
Poor quality enamel or lack of
What drugs are available for prescription in the DPF?
Dental & orofacial pain
Oral infections
Anaesthetics, anxiolytics & hypnotics
Oral ulceration & inflammation
Mouthwashes, gargles & dentifrices
Dry mouth
Minerals
Aromatic inhalations
Nasal decongestants
What is the importance of the misuse of drugs act 1971?
The penalties applicable to offences involving the different drugs are graded broadly according to the harmfulness of a drug when it is misused.
What is the misuse of drugs regulations 2001?
Define classes of person who are authorised to supply and possess controlled drugs while acting in their professional capacities and lay down the conditions under which these activities may be carried out
Principles of prescribing?
The legal responsibility for prescribing lies with the doctor (or dentist) who signs the prescription.
Treat the whole person – NOT just the condition or disease
Drugs have side effects and interactions
Drugs can kill
Medicines should be prescribed only when their use is essential
The benefits weighed against the risks involved
Children – age related dosage
Hepatic impairment
Renal impairment
Breast-feeding
Pregnancy
Elderly
What are the principles of tooth preparation?
- preserve the tooth structure
- Retention and resistance
- Structural durability
- marginal integrity
- Preservation of the periodontium
- aesthetic considerations
What are the causes of extrinsic discolouration?
- smoking
- tannins- coffee, tea, red wine
- chromogenic bacteria
- CHX
- iron suppliments
What are the instrinsic causes of discolouration?
- fluorosis
- tetracycline
- age
- amalgam
- non-vitality
- CF- grey
- hyperbilirubinaemia - green
- porphyia - red primary
How does vital bleaching work ?
long chains in extrinsic discolouration is oxidised by the bleach. Oxidation leads to reduction in the smaller molecule which are not usually pigmented. This leads to a lighter shade due to the ionic echange in molecules (metallic)
What are the indications for micro-abrasion?
- fluorosis
- demineralisation from ortho
- demineralisatio with staining
- may consider prior to veneer placement
What are the consitutes of whitening gel?
- Carbamine peroxide( ACTIVE INGREDIENT) -breaks down hydrogen peroxide and urea
- Carbopol -(THICKENING AGENT) allows for slow release
- Urea- increases pH and stabilises HP
- pigment dispensers
- preservative
- flavour
- Potassium nitrate (DESENSITISING AGENT)
- Fluoride
