Saliva Labs Flashcards
What is meant by the terms ‘mean’ and ‘standard deviation’?
Mean is the average flow for all subjects
SD gives an indication of the spread of individual values about the mean
Describe the physiological factors responsible for the differences between unstimulated flow rate and gum-base (no flavour) stimulated flow rate.
Gum stimulated flow is greater.
The stimulation is entirely mechanical.
Chewing forces stimulate the periodontal receptors.
The sensory signals stimulate the salivatroy centres.
Describe the physiological factors responsible for the difference between the flow rates produced by chewing gum-base and flavoured gum.
Chewing flavoured gum generates higher flow rates than gum base alone.
Chewing each type of gum stimulates periodontal receptors.
In addition, the flavoured gum stimulates taste buds on the tongue.
These effects add together, and produce greater flow than the chewing alone.
Give 4 conditions or circumstances in which salivary secretion may be diminished.
Salivary gland diseases (e.g. Sjogren’ syndromes)
Conditions affecting autonomic NS, incuding diabetes mellitus
Destruction of salivary gland tissue. E.g radiotherapy to head and neck
Drug induced: Patient is taking medications that reduce salivary secretion (not necessary to name specify classes of drugs.
Describe 3 reasons for the increased levels of dental caries evident in patients with reduced salivary flow
Decreased bulk clearance: Cariogenic substances are not removed and emain on the tooth surfaces, where they are metabolised to acid.
Decreased buffering: reduced levels of bicarbonate, mean that plaque acids are not buffered. H+ + HCO3 - H2CO3 H2O + CO2
Decreased amounts of antimicrobial substances: The reduced levels of antimicrobial substances, e.g. means that plaque bacteria can function unopposed.
Decrease remineralising ability: Saliva normally contains mineral salts. Reduce salivary flow means that these are not present to remineralisation that has occurred, and early carious lesions are more likely to proceed to cavities
Why is a large sample size advantagous to an experiment?
larger samples offer more precise estimates of the true population value.
Mean vs Median.
The mean (average) of a data set is found by adding all numbers in the data set and then dividing by the number of values in the set.
The median is the middle value when a data set is ordered from least to greatest
Standard deviation vs Standard error
The standard deviation reflects variability within a sample
The standard error estimates the variability across samples of a population.
Histograms vs box plots
Histograms indicate the whole frequency distribution of a variable, i.e 5 people with 0.5-1ml/min. comparisions can only be made when distriution is normal
whereas the boxplot summarises its most prominent features in quartiles. shows median not mean and shows outliers
What makes a good reasearch paper?
Replicable
Reproducible
Transparent
Not repetitive
Use of data (quantative is easier)
Peer reviewed
Representative (of intended population)
