3. Dental disease Flashcards
What is the WHO definition of health?
Health is the state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.
What are the main micro-organisms responsible for caries? (3)
Streptococcus mutans
Lactobaccilli
Actinomyces
What is the main micro-organisms responsible for periodontitis?
Porphyromonas gingivalis
Many other bacteria.
Name 6 causes of tooth surface loss
- Dental caries
- Attrition
- Abrasion
- Abfraction
- Erosion
- Trauma (injuries)
What is dental caries?
A dynamic process caused by acids from carbohydrate fermentation by oral micro-organisms, involving the exchange of calcium and phosphate ions between tooth structure and saliva.
What 4 criteria are required for caries?
- A tooth surface
- Bacteria
- Fermentable carbohydrate (sugars)
- Time
What teeth are at highest risk for carious lesions? and why?
Permanent first and second molars due to length of time erupted in the oral cavity, and their complex surface anatomy to which plaque adheres.
What acid does bacteria produce to form caries?
Lactic acid
What sugars are mainly implicated in caries? (2)
Sucrose and glucose
What ions are removed during demineralisation from the tooth structure? (2)
Calcium and phosphate
What is the critical pH of enamel, below of which decalcification occurs?
pH 5.5
What are methods of detecting caries?
Visual examination
Bitewing radiograph
Fibreoptic transillumination
Lasers
Dyes
Probe (but may cause damage)
How are streptococci involved in the cariogenic process?
A group of gram-positive cocci which includes Streptococcus mutans and Streptococcus sobrinus metabolise sugars at low pH (acidogenic) and are v important in caries initiation.
They are also called viridians streptococci.
Streptococcus mutans adheres in the in the ‘biofilm’ on teeth by converting sucrose into an extremely sticky substance called dextran. The bacteria also act by converting the sugars in the diet to acids (especially lactic acid). The acids destroy (decalcify) the enamel and dentine of the teeth. The acids cause the pH to fall and when the tooth surface plaque pH drops below 5.5 tooth demineralisation proceeds faster than remineralisation. (net tooth surface loss)
How are lactobacillus species involved in the caries process?
Gram-positive bacilli which survive at low pH (aciduric). Isolated in large numbers from carious dentine.
What is a white spot>
The earliest clinical appearance of caries, caused by loss of calcium and phosphate ions from enamel prisms.
Decalcification produces opaque whitish areas on the tooth, which are painless.
Is decalcification reversible?
To a point if the person changes their diet and reduces intake of more cariogenic carbohydrates.
What is the critical pH of dentine?
pH 6.5.
The critical pH for dentine demineralisation is higher, and as dentine is softer than enamel, caries spreads more rapidly once it reaches dentine.
What are the consequences if caries is not treated?
- Destroys enamel causing a cavity.
- Reaches dentine and spreads rapidly.
- Pt experiences reversible pulpitis symptoms: pain sweet/sour or hot/cold, subsides within secs of removing stimulus, poorly ‘localised’, approximate area.
- The inflammation causes swelling of pulp but, since pulp is confined in rigid pulp chamber, the pressure builds up. Thus severe and persistent pain in tooth.
- Swelling also stops the blood flow into the pulp - which then dies. Pain may subside for a while.
- However, dead pulp is infected with bacteria from mouth (odontogenic infection). Infection spread through root apex into alveolar bone and cause apical periodontitis. Painful, when touch or bites.
- Tooth must be RCT or XLA otherwise dental abscess, granuloma or cyst will form.
What diet advice will minimise tooth damage by caries?
- Avoid consuming sugars completely.
- Minimising non-milk sugar intake
- Eating sugar-containing products all at once and over a short period of time.
- Not eating sugars as the last thing at night.
What is arrested caries?
Under favourable conditions, a lesion may become inactive - black or dark brown in colour - and has a hard or leathery consistency.
How does caries spread into dentine?
Occurs when enamel caries extends to the amelodentinal junction.
Spreads laterally and, as it progresses, is cone shaped with base on amelodentinal junction.
As dentine is vital, it can respond by laying down reactionary or secondary dentine at surface of the pulp chamber.
What is Early Childhood Caries (ECC)?
also known as ‘nursing bottle caries’.
Describes extensive caries in primary incisors due to prolonged exposure to sugar-containing drinking in a feeding bottle or cup. Teeth most likely affected are maxillary anterior teeth.
Children fall asleep with sweetened liquids or feed children sweetened liquids multiple times during the day.
What is occult caries?
Describes extensive dentine caries in the presence of minimal or no clinically evident enamel breakdown. Most commonly occurs under occlusal surfaces.
An increasing problem win older children/teenagers.
May be due to increased resistance to enamel breakdown as a result of exposure to fluoride.
What is radiation caries?
Caries in people after irradiation that damages salivary glands causing hyposalivation, predisposing to caries.
What is rampant caries?
Causes in adults?
Gross caries, frequently in deciduous dentition.
‘Rampant caries’ in adults is advanced or severe decay on multiple surfaces of many teeth seen in individuals with poor oral hygiene, stimulant use (due to drug-induced dry mouth), dry mouth such as after radiotherapy in head and neck region or Sjogren syndrome, and or large sugar intake.
What is recurrent caries?
Continuation of caries after placement of restoration.
What is root caries?
Occurs following gingival recession. Varies from light yellow to dark brown in colour. Increasing problem in older patients.
What is secondary caries?
New caries occurring at restoration margins.
