Unit 308/315 Dental Caries Flashcards
What causes enamel and dentine to demineralise (dissolve)?
Weak in-organic acids created by oral bacteria as they digest carbohydrates.
After a carbohydrate source has been consumed, how long does it take the bacteria to digest the sugar in a dental plaque structure?
1-2 minutes, after which demineralisation occurs as the acid produced dissolves a microscopic layer of enamel.
How long does it take saliva to neutralise the acid, restore the mouths pH level and repair microscopic demineralisation? What is this called?
Between 20 mins-2 hours. This is called remineralisation.
Why do caries spread more quickly in dentine compared with enamel?
Because dentine has a hollow structure and a lower mineral content compared with enamel.
What is the name of the cells which try and protect the underlying pulp tissue from the bacteria by laying down secondary dentine?
Odontoblast cells which lie at the ADJ.
What is pulpitis and what symptoms will the patient have?
When pulp tissue becomes irritated and inflamed if caries are allowed to spread deep enough. The patient will begin to feel sensitivity to temperature changes and sweet foods. This is because the nerve fibrils within the hollow structures of dentine will be stimulated as caries progresses.
What is reversible pulpitis and how can it be treated?
When pulp tissue is inflamed but can still be removed by the dentist and restored with a filling. The tissue will then settle and the tooth will return to normal function.
What is irreversible pulpitis and how can it be treated?
When caries reach the pulp chamber (or its immediate surroundings). The level of inflammation is too great to be resolved by simply removing the decay and the pulp will eventually die due to carious exposure. Patient will be in pain and kept awake at night. Can only be treated with endo or XLA.
Explain treatment and advice to help prevent caries.
Control of bacterial plaque
Dietary advice including frequency of sugar etc
Topical fluoride application
Fissure sealants
Why are patients who consume processed carbohydrates between meal times are of high risk of developing caries?
Provides a constant acidic environment for demineralisation if enamel to occur, with insufficient time between intakes of sugar for the natural defence mechanism of remineralisation to occur. The saliva does not have enough time to neutralise the acid.
Name some examples of foods with ‘hidden sugars’.
Tomato based sauces, ketchup, flavoured crisps, ketchup, breakfast cereals, soups, tinned fruit.
What are the two methods of topical fluoride application do the dental team carry out?
Fluoride gel applied in trays over all teeth for several minutes. Often used on patients with special needs and/or those with a high caries risk.
Fluoride varnish (Duraphat products) which is applied to individual teeth showing areas of acid attack or root exposure due to gingival recession.
How are cavities prepped by the dentist?
All plaque and soft carious tissue is removed. As much enamel and dentine is conserved as possible (the minimum amount of healthy tooth tissue is removed).
What are the aims of cavity preparation and restoration?
Restore normal function Restore aesthetics Restore retentive shape Prevent stagnation areas Alleviate any pain/discomfort Permanent and long-lasting solution (dependent on patient's standard of OH and diet)
What are the 5 methods of achieving retention for plastic fillings?
Undercutting Dovetail Dentine pins Acid etching Chemical bonding
When are temporary fillings likely to be used?
Emergency measures to seal a cavity
During endo treatment when a tooth will need accessing again
To allow a symptomatic tooth to settle before a permanent filling is placed
What are the 4 materials used for temporary restorations?
Zinc oxide and eugenol
Zinc phosphate
Zinc polycarboxylate
Gutta percha
When is amalgam likely to be used?
Most widely used permanent restorative material for posterior teeth due to good set strength and excellent longevity.
What do amalgam capsules contain?
Powdered alloy (silver, copper, tin, zinc) and liquid mercury.
During a deep amalgam restoration, why might a cavity lining need to be used? What is the name of this lining?
To insulate the pulp from thermal shock/injury. Calcium hydroxide or zinc based temporary cements can be used for this.
When is glass ionomer likely to be used?
Used in permanent restoration fillings. Adhesive to all the hard tissues of the teeth and is therefore used in situation where there’s little natural retention available.
What does cavity conditioner do and what is it made of?
Increases adhesion and improves marginal seal. Contains either polyacrylic acid or tannic acid.
During a deep glass ionomer restoration, why might a cavity lining need to be used? What is the name of the lining?
To protect the pulp from the acrylic acid in the GIC. Calcium hydroxide is used.
When is composite likely to be used?
Most widely used permanent restorative material for anterior teeth.
During a deep composite restoration, why might a cavity lining material be used? What is the name of this material?
To protect pulp from chemical shock. Calcium hydroxide or glass ionomer.
What are fissure sealants and when are they likely to be used?
They are a caries prevention measure for vulnerable occlusal fissures and pits (stagnation areas). Commonly done on children.
What materials can be used for fissure sealants?
Unfilled composite resins e.g Helioseal or glass ionomer
What are unfilled composite resins?
Liquid bases containing just the resin without the filler.
What are the 5 methods of moisture control?
High-speed suction (wide bore aspirator) Low-speed suction (saliva ejectors) Absorbent materials (cwr, cotton pledgets, dryguard) Rubber dam Compressed air drying
Explain why it is important to finish and smooth restorations properly.
Correct occlusion in harmony with the rest of patient’s dentition
Maximise aesthetics by achieving a polish/lustre
Minimise risk of surface staining
Smooth surface which patient can test with their tongue, ensuring no overhangs or excess material
What are the techniques used to smooth/finish restorations?
Fine abrasive stone
Fine abrasive wheels, discs, brushes and strips
Finishing burs
Polishing pastes
What matrix system is used on posterior teeth?
Metal band (Siqveland or Tofflemire). Adapts to tooth to prevent overspill in cavities of two or more surfaces (class II).
What matrix system is used on anterior teeth?
Transparent matrix strip. Placed interdentally to separate tooth from its neighbour. Strip is transparent to allow light curing to occur through it (as composite is most commonly used on anterior teeth). Strip can either be held manually or with a holder system.
What matrix system is used on class V cavities?
Cervical foil matrix system. Foil coated and preshaped for use when restoring class V cavities. Curing lights will not penetrate through them. Used on posterior teeth to produce a smooth cervical margin surface.
