Oral Environment Front Page

Newcastle University Dental School Learning to Learn Blackboard

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Dentistry	Fluoride	Gingivitis	Caries	Mouthrinses	Periodontal Disease

MCQ TESTS

Saliva
Composition
Gingival fluid
Gland histology
Gland development
Salivary proteins
Salivary gland
Saliva secretion
Gland abnormalities
Saliva flow
Critical pH
Saliva & oral flora
Tooth pellicle

General microbiology
Nature of microbes
Bacterial structure
Bacterial growth
Bacterial cultivation
Identification
Aetiology
Pathogenicity
Control
Antibiotics

Oral microbiology
Oral diseases
Bacterial ecology
Bacterial adhesion
Supragingival plaque
Subgingival plaque
Sugar metabolism
EPS
Plaque physiology
Plaque fluid
Mutans streptococci
Dental abscesses
Periodontal diseases
Periodontal bacteria

Oral disease control
Predicting caries
Fluoride
Antimicrobials
Periodontitis control
Control strategies

What's Current

Is Strep mutans really the aetiological agent of dental caries? Or is it just plain old vanilla dental plaque that's to blame?

It is common to read in the scientific literature that dental caries is an infectious disease. But is it really infectious? Here is an alternate view.

Dental plaque formation
Dental plaque is the aetiological agent of the two major oral diseases caries and periodontal disease. It is a complex community of microorganisms attached to the surface of teeth. The microbial composition of plaque is variable and reflects, among the many environmental factors in the mouth, the site of its formation and the host diet.

Learn more about:
>	Why plaque forms where it does: saliva shear force and plaque development.
>	Events in plaque formation: pioneers species, colonisation,outgrowth, succession, climax communities and the effect of diet
>	Electrostatic charge and bacterial adhesion: why bacteria must attach and what's so special about surfaces
>	Fimbriae, fibrils, sex and fuzzy coats: what all this has to do with plaque and the low down on bacterial sex (includes pictures)
>	Extracellular polysaccharides: NEW what are they, how are they made, what makes them and what their role is in plaque. There's even some basic sugar chemistry to help you understand the terminology

Some bacteriology
Bacteria are at the root of dental plaque and how it causes disease. It is, therefore, inevitable, that you will need to understand the basics of bacteriology if you are to understand what is happening in the oral environment.

Learn more about:
>	these streptococci thingies
>	what kissplates can tell us about the mouth
>	the Gram Stain, how to do it and what it means
>	the significance of bacteria strains and how bacteria are typed
>	why bother identifying bacteria?
	Some essentials of bacterial growth NEW
>	Bacterial growth, the maths NEW
>	selective and Indicator Media (coming soon)

Saliva and tooth Protection
Saliva protects the teeth in many ways but mainly by neutralising acid and affecting mineral dissociation equilibria by means of its calcium phosphate content.

Understanding how these are related requires knowledge of ionic and solubility products and the meaning of pK. Saliva also exerts a powerful controlling effect over the microbes which inhabit the mouth through its shearing action, by directly inhibiting certain species, by providing microbe-specific receptors and through non-specific inhibitors.

Learn more about:
>	acid neutralising by saliva why it isn't really buffering and why it is so important
>	saliva calcium phosphate and how it protects teeth
>	ionic & solubility products and why they are important if you really want to understand what is going on in the mouth
>	pK and how this will help you understand how bicarbonate helps protect teeth
>	calculus, what is it, is it the same as tartar, how does it form, why is it a problem and how can we inhibit it

Plaque physiology
The microbes in dental plaque ferment carbohydrates in the host diet and produce a mixture of organic acids as by-products. The effect of these organic acids on tooth demineralisation is modulated by a variety of factors such as saliva flow rate; bicarbonate concentration, saliva concentrations of calcium and phosphate. The sum of all these effects are described by Stephan Curves.

Learn more about:
>	the basics of Stephan Curves
>	the clinical value of Stephan Curves
>	Plaque acids: which are made and why (to come)

Please do not copy any of this material without permission of the author. Contributions, constructive criticism and bug reports are encouraged and gratefully received but the author is unable to offer any medical advice and will not respond to any requests for it. Otherwise feel free to contact me here