Management of caries Flashcards
What is the multifactorial aetiology of caries?
Caries is caused by a variety of factors e.g. Plaque accumulation and retention Frequency of carbohydrate intake Exposure to acids and frequency Pellicle Saliva free of acidogenic bacteria Fluoride Protective dietary factors e.g. dairy
What are the 3 stages of caries management?
Preventive
Minimal invasive
Restorative intervention
Give 5 ways to help patient prevent caries
Assessment of diet (3 day diet sheet) Causes of extrinsic and intrinsic acid Effective tooth-brushing Salivary flow assessment Optimal fluoride exposures (gels, varnish, mouthwash, toothpaste)
Why restore? (4)
'Best denture is no denture' Failed alternative preventative measures Function impaired Loss of contact point and subsequent tooth movement Aesthetic reasons
Why are fissure sealants important?
Fissures in teeth can favour plaque stagnation, especially during eruption of tooth
What is a fissure sealant?
Resin coat physically attached to tooth via acid etch technique
2 advantages of fissure sealants
safe and effective
does not involve cutting tooth
What is preventive resin restoration (PRR?)
PRR placed after minimally excavating existing occlusal caris up to ADJ using tungsten carbide in air-turbine or air-abrasion technique.
Debates as to whether we should do this or not
In PRR, what material would be used to restore tooth?
Composite or GIC, then fissure seal unrestored fissures on remaining sound portion of tooth
6 instruments for surgical intervention in caries management
Rotary instruments Hand instruments Sonic and ultrasonic instruments Air abrasion Pulsed Erbium Laser Chemo-mechanical caries removal (Cariosolv) - not popular anymore but great for kids/ out in field. denatures proteins, then scoop out
4 types of rotary instruments
High speed air turbine (400-600,000rpm - a lot of pressure). Diamond bur
Low speed contra-angle (various torques)
Intermediate high speed
Ultra-high speed
How do rotary instruments function?
Remove tooth structure by chipping it away or grinding
Which bur is a ‘beginner’ bur?
Tungsten carbide
What are burs often coated with?
Diamond coated
4 shapes of burs and their uses
Flat fissure: suitable for extending cavity along fissure or widen proximal box
Tapered fissure: designed to develop retentive grooves and pinholes
Round: suitable to remove caries and develop retentive holes
Pear shaped: suitable to create undercut
What is particularly important when using rotary instruments?
Coolant as they generate heat - could kill tooth
4 limitations of rotary instruments
Visual contact with bur head (small)
Application load - tactile sense (esp. high speed)
Lubrication
Annoyance factor (spray, sound and pain)
What is a gingival margin trimmer used for?
To plane enamel margins where access is limited and for conservation
Gives nice finish to make filling last longer
What is a spoon excavator used for?
For removing caries and for final removal of softened demineralised infected dentine
4 advantages of sonic or ultrasonic tips
Good control of caries removal (selective)
Suitable for minimal invasive procedures
Reduced annoyance factor compared with conventional spherical bur (less pain, no drilling noise)
Good view
What is air abrasion also known as?
Kinetic Cavity Preparation
How does air abrasion work?
Uses kinetic energy of microfine (20-50) particles of alumina in high pressure steam
Removes tooth structure by brittle microfracture
Sickle or contra-angle handpiece used
What alternative powders can be used in air abrasion except for alumina?
Sodium bicarbonate, urea, dolomite
What are the main indications for air abrasion? (4)
Minimal occlusal cavities localised in enamel
Limited debridement of dentine lesions with no LA
Micro-etching of metallic and ceramic surfaces (crowns) prior to cementation
Removal of extrinsic stains from teeth
6 limitations of air abrasion
Distinct learning curve required
Loss of tactile feedback so tendency to overcut
Doesn’t effectively remove smear layer from dentine
Not suitable for grossly carious dentine
Not suitable for pxs/ dentists with asthma or airway disease
Expensive
Which laser systems are the most effective for cutting cavities?
Erbium based laser systems
How do pulsed erbium lasers work?
Rely on high absorption bands within tooth structure in middle and far infrared regions (OH, H2O, H2CO3, PO3- are major absorbing components of enamel)
Laser transfers water to steam via rapid heating leading to mini explosions and ejection of crystallites
Carious enamel and dentine are rich in water
Why don’t teeth get too hot under pulsed erbium lasers?
Evaporated water creates cooling effect
4 advantages of laser
Reduced need for anaesthesia
Low annoyance factor
Creates surface suitable for adhesive bonding of restorations (macro-roughing effect)
Suitable for minimal invasive procedures
4 disadvantages of laser
No tactile - dentist relies on sound of tooth when ‘hit’ by laser to determine presence or absence of caries
Learning curve
Slower removal of tooth structure
Expensive
