Flashcards in Epidemiology Of Periodontal Disease Deck (37)
What does prevalence measure, and what is the formula to calculate it?
Prevalence = number of new cases at a given time divided by the number in the population at a given time
-measures how much of some disease or condition there is in a population at a particular point in time
What does incidence measure, and what is the formula used to calculate it?
Incidence = number of new cases of disease in specified time divided by the population initially disease free
-incidence measures the rate of occurrence of new cases of a disease or condition in a specified time period divided by the size of the population under consideration who are initially disease free
What does extent describe?
-how widespread the disease is in subjects
What is severity?
Examples would be mean CAL, mean bone loss, etc
What are the 7 main uses of epidemiology?
1) to study the rise and fall of disease in population
2) to diagnose community problems of health and disease
3) to estimate the individual risk and chances of developing disease
4) to help in completing clinical picture and natural history of disease by group analysis
5) to identify clinical syndromes by observation of group behavior
6) to evaluate the need and effective of health services and need for man power
7) to search for cause of disease and health by observation of group habits, customs, and lifestyle
Name the 3 observational study designs of epidemiology
Cross-sectional studies, cohort studies, and case-control studies
What are cross-sectional studies?
The presence or absence of disease and the characteristics of the members of a population are measured at a point in time
How are cross sectional studies useful?
They provide prevalence data on a disease, comparing the characteristics of persons with and without disease, and generating hypotheses regarding the etiology of a disease
What are cohort studies?
-subjects are classified into exposed and unexposed groups and then followed over time and monitored for the development of disease
-all subjects must be free from disease at the beginning of the study
-purpose is to determine whether an exposure or characteristics is associated with the development of a disease or condition
-disadvantages: can require long periods of follow up and can be expensive to conduct
What are case control studies?
-provides efficient way to investigate the association between an exposure and a disease, especially a rare disease
-require fewer resources and can be conducted quicker than cohort studies
-prevalence or incidence cannot be determined because the subjects are recruited into study based on their disease status
-disadvantage: temporal relationship between exposure and onset of disease cannot be determined because the exposure is usually assessed when the disease status is established
What is an index?
-a numerical value describing the relative status of population on graduated scale with definite upper and lower limits
-designed to permit and facilitate comparison with other population classified by the same criteria and method
What are the 9 characteristics of an ideal index?
What is the difference between parametric and non parametric?
-parametric makes assumptions about the parameters of the population distribution
-non parametric does not make any assumptions
what is microbial plaque?
-the soft deposits that form the biofilm adhering to the tooth surface or other hard surface in the oral cavity
-aka microbial biofilm, consisting of micro-organisms, organic compounds, and inorganic compounds
what are the main categories of periodontal disease?
what is periodontal disease?
-an infectious disease process that involves inflammation
-results of loss of tissue attachment and destruction of the alveolar bone
what is plaque associated periodontal disease?
-an inclusive term describing any disease of the periodontium with two basic forms: gingivitis and periodontitis
what is periodontal health?
defined as a state in which the tissues are free from clinical inflammation
what is gingivitis?
an inflammatory process confined to the gingival tissues
-caused by nonspecific accumulation of plaque
what is periodontitis?
-inflammation not confined to the gingiva, but involves the attachment apparatus
-starts as gingivitis, but progresses to destroy the bone and soft tissues that support the tooth
what does the plaque index (silness and loe) measure?
the accumulation of plaque on surfaces of the teeth
what are the numerical values of the silness and loe plaque index, and what do they mean?
0 - no visible plaque and no plaque on sweep with the periodontal probe
1 - no visible plaque, but present upon sweep with periodontal probe
2 - mild to moderate visible plaque at the gingival area
3 - heavy plaque filling the gingival crevice; interdental area is also filled with debris
*these values are not quantifiable with statistics
what is the simplified oral hygiene index (greene and vermillion)?
similar to the silness and loe index, but measures debris or calculus (two difference indexes)
what are the numerical values of the simplified oral hygiene index for debris, and what do those values represent?
0 - no visible debris or stain present
1 - debris or extrinsic stain covering up to 1/3 of the tooth surface
2 - debris or extrinsic stain covering between 1/3 and 2/3 of the tooth surface
3 - debris covering more than 2/3 the tooth surface
what are the numerical values of the simplified oral hygiene index for calculus, and what do those values represent?
0 - no calculus
1 - supra-gingival calculus covering up to 1/3 of the tooth surface
2 - supra-gingival calculus covering between 1/3 and 2/3 of the tooth surface or flecks of sub-gingival calculus
3 - supra-gingival calculus covering more than 2/3 the tooth surface or sub-gingival band of calculus
what is the plaque score (lenox and kopcyzk)?
-a calculation used to quantify plaque present on tooth surfaces
-% score is determined by (number of sites with plaque divided by 6x the number of teeth present) x 100
what is the gingival index (loe and silness)?
-a non-quantifiable measure of inflammation
what are the numerical values for the gingival index?
0 - normal gingiva with no signs of inflammation
1 - mild inflammation, no bleeding on gentle sulcus sweep
2 - moderate inflammation, bleeding on gentle sulcus sweep
3 - severe inflammation, ulceration, tendency to bleed spontaneously
what is the gingival score?
very similar to the plaque score, but bleeding sites are counted instead of sites with plaque