Operative Flashcards
What are the three things that must be present at the same time for caries to occur?
cariogenic bacteria
susceptible tooth surface
available food for bacterial growth
At what pH does enamel breakdown? Dentin?
5.5 (enamel)
6 (dentin)
Step mutans
nonmotile
gram(+)
cariogenic bacterium, primary causative agent for caries
Explain why strep mutans is the primary causative agent for caries.
Strep mutans is able to adhere to the tooth surface by having a glucosyltransferase enzyme that produces an extracellular polysaccharide that sticks to tooth surfaces.
It uses sucrose to convert to glucans and fructans that extrude from bacterium and allow for adherence to tooth
It produces and tolerates acid (metabolizes succrose to an end product of lactic acid)
It also produces bacteriocins that beats its competition
What bacterium takes over dentin destruction once the intial caries broke through the enamel?
Lactobacillus
What minerals are found in saliva and is used to remineralize enamel?
Na,K, Ca
What happens when plaque is exposed to sucrose?
The plaque metabolizes sucrose and produces acid on tooth surfaces starting demineralization process
Why is saliva a protective mechanism for teeth?
Glycoproteins in saliva cause some bacteria to agglutinate and then removed via swallowing the 1.5 L of saliva we produce a day.
Saliva has buffering action because of its urea content
which helps dilute the acid in saliva
Has antimicrobial actions: antibodies, lysozyme, lactoferrin (binds to iron), lactoperioxidase (inactivates enzymes), IgA (fights)
What are the beneficial effects of fluoride?
Bacteriocidal to bacteria
Forms fluoroapetite during remineralization
What are the benefits of xylitol?
keeps sucrose from binding with strep mutans
strep mutans is unable to ferment xylitol
True or False
When cavitated lesions are discovered the first step is to have them rinse with an antimicrobial rinse tx before filling restoration.
False
If antimicrobials are used first they would disrupt the normal flora and allow the virulent organisms in the protected cavitated areas flourish
True or False
Restorations prevent the adherence of bacteria
True
Order of restorative tx plan
- restoration
- sealant
- intense short term use of agents
- xylitol products
- fluroide rinse OTC
- Recall 3 mo after CHX and fluoride varnish
- additional 3 mon recalls check sealants
What kind of radiograph is best for root caries?
vertical bitewings
When should you consider restoring abraded or eroded areas?
- caries involved
- affects structural integrity
- intolerable sensitivity
- defects contributes to periodontal problem
- area involved in the design of a removable partial denture
- the depth of defect is judged to be close to the pulp
Explain hydrodynamic theory
Postulates that pain results from indirect innervation caused by dentinal fluid movement in the tubules that stimulates mechanoreceptors near the predentin.
Any tx that can reduce these fluid shifts by partially or totally occluding the tubules may help reduce sensitivity
What is the best treatment for dentinal sensitivity?
Dentin bonding agents
What can you do to treat a localized amalgam defect?
Can be locally repaired with amalgam or with unfilled sealant resins
List indirect tooth-colored restorations materials. (5)
- processed composite
- feldspathic porcelain
- cast ceramic
- CAD/CAM
- Cast metal
Describe processed composite.
improved wear resistance compared to direct composites; indicated primarily for class 1 and 2 restorations but in low to moderate stress areas
Describe feldspathic porcelain.
highly esthetic but high fracture incidence and wear opposing teeth
Describe cast ceramic
has excellent marginal fit, low abrasion of opposing tooth and superior strength
Describe CAD/CAM ceramics
same day system
Describe cast metal.
the treatment choice for patients undergoing occlusal rehab and teeth with subgingival margins
What are high, moderate, and low speeds of hand pieces?
High - >200K rpm
Mod - 12K-200K rpm
Low - <12K rpm
define surface speed of the instrument
the velocity at which the edges of the cutting instrument pass across the surface being cut
