Community epidemiology Study the disease patterns among groups - PowerPoint Presentation

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Community

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epidemiology

Study the disease patterns among groups

Collect data to describe normal biologic processesUnderstand the natural history of a diseasePrevention and control of disease

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TYPES OF EPIDEMIOLOGY

DESCRIPTIVE

– identify and report pattern and frequency of health events, collect data, disease state of a community, evaluates disease status by looking at incidence and prevalence of disease in a given populationPERSON, PLACE, AND TIME (needed to describe the patterns of health and disease)ANALYTIC – focuses on health outcomes, collects data and analyzes data to answer a certain question, looks at relationships between factors associated with a diseaseEXPERIMENTAL – determines effectiveness of an oral health program and therapeutic intervention of a diseasewww.dentalelle.com3

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Characteristics of epidemiology

Study of GROUPS (not individuals)

Disease state depends on exposure to specific agent, strength of agent, susceptibility of host and environmental conditionsRisk factors attribute the likelihood of developing a particular disease or negative health condition in the futurePreventive Intervention used to eliminate risk factors and reduce the occurrence of a diseasewww.dentalelle.com4

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Concepts in epidemiology

Rate

 Number of actual and possible occurrences of the diseaseIncidence  The incidence of a disease is the rate at which new cases occur in a population during a specified period. Expressed as a ratePrevalence  A measure of the total number of people in given population who have a certain disease at a specific time. This is a common measure used when describing how widespread or common a given disease is.Expressed as a percentage or

proportion

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Definitions

Morbidity Rate

A disease rate, specifically prevalence and incidence rates of diseases in a population in a specified time periodMortality Rate  The number of deaths from all causes divided by the total population at a particular time and placewww.dentalelle.com6

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Continued

Epidemic

 spreading quickly by infection and affecting many people in an area or population AT THE SAME TIMEEndemic  disease with an expected number of cases that continues. Could be specific to an area or population. EXPECTED DISEASE PREVALENCEPandemic  disease affecting persons over a wide area. SPREAD WORLDWIDEwww.dentalelle.com7

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continued

Acute

 begins quickly and then subsides after a short period of timeChronic  condition develops slowly and persists for a long period, could be lifetimewww.dentalelle.com8

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Concepts

Cluster

 A grouping of health-related events that are closely grouped in time or spacePopulation Risk  Includes persons in the same community or population group who can acquire a disease or conditionRisk Probability that a specified event will occur. Individual will exhibit a disease or die within stated period of time or by certain ageRisk Factor

 An attribute or exposure that increases probability of disease occurrence

and if

it is taken away, the risk of the disease

diminishes,

c

an

be

modified

and

d

emonstrated longitudinally.

Risk Indicator



It cannot be confirmed since longitudinal studies are impractical or

unethical

, associated

with a disease in cross-sectional

data and a sample

of a particular population assessed at one

time

Risk

Markerr



An attribute or exposure associated with increased probability of a

disease and cannot

be modified. Useful in statistical models to predict disease occurrence and not useful in disease prevention

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Survey

Surveys are used to collect data and record prevalence of various conditions

Assess trends in health and diseaseFor example – looking at the percentage of patients who use an oral b toothbrush over a sonicare toothbrush, you need to do a survey to determine the percentagewww.dentalelle.com10

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Cross-Sectional

A descriptive epidemiologic study design that uses a representative sample of the population to collect information on current health status, personal characteristics, and potential risk factors at one point in time

A true reflection of an entire population (risk factor and disease)This is inexpensive and quick.An example could be looking at cat hair and determining what happens when someone is allergic to cat hair, becomes exposed.www.dentalelle.com11

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Longitudinal

A study in which the same group of people is studied on 2 or more occasions so that the incidence can be assessed

Requires at least 2 series of measurements among same people at different times to determine progress of the condition over specified time period PROSPECTIVE  planning a study BEFORE data is collected and analyzed. The outcomes are compared afterwards. A population is followed through.Example – people who brush their teeth once a day vs people who brush their teeth twice a daywww.dentalelle.com

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Retrospective

Observations and data that were collected in the past are looked at

Used to study rare conditionsAnalytic Study  groups are studied together to make comparasionswww.dentalelle.com13

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Ecologic Study

Population is looked at rather then one single person

Looking at something a population is given and how it affects that populationExample  how does well water affect the populationwww.dentalelle.com14

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Clinical trial

Clinical trail

 used to evaluate specific diseases, or dental hygiene techniques. Test groups receive the agent and the control group does not (to compare)www.dentalelle.com15

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Independent variable

Experimental group is exposed to an experiment

You need to cause or influence the “Dependent Variable”The investigator has all the control.www.dentalelle.com16

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Dependant Variable

Caused by the “independent Variable”. Dependent variable would be the how well someone brushes and the independent variable would be teaching some how to brush

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Randomized trial

Randomly being assigned and this can improve validity and decrease bias

Nonrandomized trial  weaker, this may not be as valid as a randomized trialwww.dentalelle.com18

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Crossover design

Subjects are their own controls

Active treatment or no treatment during a control period with a groupSHORT TERM trials www.dentalelle.com19

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Double blind trail

MOST VALID

Nobody knows who is being studied – so who is the experimental group and who is the control groupPlacebo  the patient THINKS something is workingwww.dentalelle.com20

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Efficacy study

To see if something works

Researchers need to make sure that agent is being used to its intentwww.dentalelle.com21

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Reliability

Looking at diseases that happen over a short period of time. Examiners may diagnose in the early stages which allows for more chance of error

FALSE NEGATIVE TEST – test result that is negative when the person is HAS THE DISEASEFALSE POSITIVE TEST – test result that is positive when the person DOES NOT HAVE THE DISEASEwww.dentalelle.com22

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Parametric tests

Measure variables that follow normal distribution

P – VALUE : measures things that occurred by chance during an experimentLess .05 SIGNIFICANT STATISTICAL RESULT Greater .05 INSIGNIFICANT STATISTICAL RESULT

.05 DIFFERENCE OCCURED BY CHANCE

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Oral disease

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Keep in mind that when an individual does things that put them at risk for a certain disease, they are more likely to get that disease

Someone who eats healthy everyday will likely live longer then someone who eats McDonalds everyday

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methods

Counts

 The simplest form of measuring oral disease, and most useful with unusual conditions of low prevalenceProportions  A count can be transformed into a proportion by adding a denominator, thus determining prevalence. Calculating a percentageRate  seeing if death by cancer ‘rate’ has increased or decreasedwww.dentalelle.com26

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indicies

Reversible index and irreversible index

 cumulative conditions that can be reversed or notwww.dentalelle.com27

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continued

CONTENT VALIDITY

– Something thoroughly represents knowledge in the selected content areaCRITERION VALIDITY - Compares with pre-existing valid and reliable products in order to evaluate accuracy and appropriateness of something newRELIABILITY – measures consistency at different timesIntrarater and Intraexaminer – two people may exam things differently even if looking at the same thing so it is important to use the same indices and products so that results are reliablewww.dentalelle.com28

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Sampling

Probability Sampling

 Different units in the population have equal probabilities of being chosenNonprobability Sampling  Cannot identify or do not have access to the entire population of interestSimple random Sampling  Each item or person in the population of interest has an equal chance of being selectedStratified Random Sampling  Method of sampling used to represent subgroups proportionately in the sample when they are known to exist in the populationCluster Sampling  the population is spread over a large areaSystemic Sampling

 Random and it

spreads the sample more evenly over the

population

Quota Sampling



Like stratified sampling, the researcher first identifies the stratums and their proportions as they are represented in the population

Convenience Sampling



Subjects are recruited as they arrive and the researcher will assign them to demographic groups based on

age

and gender

.

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Dental caries

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DMF and def

DECAYED, MISSING, AND FILLED TEETH.

DMF  Irreversible, uppercase letters for permanent dentition, score = 0 to 32, can be applied to whole teeth or surfaces (DMFS)DECAYED, EXTRACTED AND FILLED TEETH.Def  Can be applied to whole teeth or surfaces (defs), primary

or mixed dentition, missing teeth for caries are not recorded

DMFT count

= Total DMFT divided by the population examined

deft count

= Total deft divided by the number of children examined

FNM

= Total filled teeth divided by total DMFT

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DMFT

Decayed Teeth

= Total decayed teeth divided by total DMFTThis indicates treatment required for unmet filling needsMissing Teeth = Total missing teeth divided by total DMFTThis indicates the number of teeth lost by decayAverage Decayed/Missing/Filled teeth per person = D/M/F teeth divided by number of people examinedUTN = Mean number decayed teeth divided by mean number decayed plus filled teeth and this indicates the Unmet Treatment Needs

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Remember *

Mean = AVERAGE

Median = MIDDLEMode = OFTENwww.dentalelle.com33

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TAKING RADIOGRAPHS

It is SO important to take radiographs, especially on children because often decay that has gone through the dentin can be missed. Everything may look fine clinically but radiographs could show otherwise.

You may notice decay in a radiograph that is large, but in the mouth the tooth seems finewww.dentalelle.com34

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What is this?

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35Cervical Burnout  this is normal and NOT caries. Notice it is right at the mesial and distal aspects.CARIES is more of a saucer shape below the CEJ

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Periodontal disease

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Gingival INDEX

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37Developed in 1960’s by Loe & SilnessIndex most frequently used to evaluate gingivitisBleeding is most critical factorAssess bleeding, color, contour, and ulceration of tissueGrades gingiva on M, D, B, L surfaces

Use on all or 6 selected teeth

GI Index =

Total

score divided by

#

surfaces

Excellent = 0

Good = 0.1 – 1.0

Fair = 1.1- 2.0

Poor = 2.1 – 3.0

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Assess bleeding of gingival margin in

response

to gentle probing

Used as an indicator of gingival health or disease

# bleeding

areas divided by g

ingival

margins examined x 100

+ = bleeding within 10 seconds after gentle probing

- = absence of bleeding after 10 seconds after probing

A positive score indicates percentage of all gingival areas explored that bleed in response to probing

Gingival bleeding

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PERIODONTAL INDEX (PI)

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Developed by Russell in 1956

Assesses progressive stages of periodontal disease and amount of attachment loss present on each tooth

Easy to use and comprehend

Primarily used for major population groups

Tissues

examined for gingival inflammation, pocket formation and masticatory function and given a score

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remember

Attachment loss

= sum of clinical probe depth and gingival recessionRecession - measured from CEJ to gingival margin www.dentalelle.com40

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PERIODONTAL DISEASE INDEX (PDI)

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Evaluates gingival health, probing depths and plaque and calculus deposits

Used for

Ramfjord

teeth:

16; 21; 24; 36; 41; 44

Gingiva given a score 0 – 3

Pockets given a score 4-6

Critical measurement is distance from CEJ to base of sulcus

1st

-

measure the gingival crest to base of pocket to record pocket depth

2nd

- CEJ is located by touch and depth from CEJ to gingival crest is recorded

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0 = Absence of inflammatory signs

1 = Mild-to-moderate inflammatory gingival change that does not extend around the tooth

2 = Mild-to-moderately severe gingivitis that extends around the tooth

3 = Severe gingivitis characterized by marked redness, swelling and the tendency to bleed and ulcerate

4 = Gingival crevice extends apically past the CEJ but no more than 3 mm

5 = Gingival crevice extends apically 3 to 6 mm from the CEJ

6 = Gingival crevice extends apically more than 6 mm from the CEJ

PDI SCORING

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CPITN – COMMUNTY PERIO INDEX

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PERIODONTAL

SCREENING & RECORDING (PSR)

Not

intended to replace a complete periodontal examination

Acts as a screening system to indicate when a full-mouth comprehensive examination is

required

Evaluates

pockets, bleeding and plaque retention

factors

Evaluates

6 sextants - 1 score from each sextant is

used

Excludes

8’s unless they function as

7’s

Requires own periodontal probe (CPITN-E probe) which has 0.5mm diameter ball at its tip,

color

coded for visibility between 3.5 + 5.5 mm and circular markings at 8.5 + 11.5 mm

What is the ball used for on the end of the probe?

T

o

assist in detection of overhanging margins and subgingival calculus and to facilitate assessment of base of pocket which reduces risk of

over measurement

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6’s and 7’s in posterior sextants are examined and only the deepest probing depth of each sextant is

recorded, one maxillary anterior tooth and one mandibular anterior tooth are examined

Sextant

with no teeth or 1 tooth is recorded as missing and marked “X” on record

form

TN 0 = NO TREATMENT REQUIRED

TN 1 = REQUIRES IMPROVED OSC

TN 2 = REQUIRES IMPROVED OSC & DEBRIDEMENT

TN 3 = REQUIRES IMPROVED OSC, DEBRIDEMENT & COMPLEX TX

CODE 0, CODE 1, CODE 2, CODE 3, CODE 4

Scoring psr

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SIMPLIFIED ORAL HYGIENE INDEX (OHI-S)

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Developed in 1960 by Greene and Vermillion; was modified 4 years later

Useful for large populations

Scores plaque and calculus together (both supra and subgingival)

Silness and Loe developed a Plaque Index (PI) designed to be used along with GI

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Developed in 1967 by Silness and Loe

Assess thickness of plaque on teeth at the gingival margin

Specific teeth or entire dentition can be assessed using D, M, F, L surfaces

Visually examine plaque or use a probe to swipe along cervical third of teeth; disclosing agent can be used

The main difference between PI and OHI-S approach is that PI scores plaque according to its thickness at gingival margin rather than its coronal extent

0 - 3 ordinal scale is

used

# plaque surfaces

present

divided by #

tooth surfaces examined x 100 = P

Plaque index (pi)

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Classification of perio

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Classification of GINGIVITIS

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periodontitis

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explained

1.

Anug – trench mouth, odor, starts in interdental papilla, grayish/yellowish “pseudomembrane” , poor OH, stress, crater appearance 2. Acute Herpetic Gingivostomatitis– infection causes by herpes simplex virus, most common with children under 6, redness, bleeding, vesicles burst to form painful ulcers3. Disquamative Gingivitis  redness, burning, red and shiny patches, surface may peel away to expose underneath, VERY painful4. Pericornitis  partially erupted tooth, the gingiva is red and swollen5. Gingival Abscess  Localized, painful and rapidly progressing lesion that develops suddenly, popcorn kernel, etc.6.

Pregnancy Gingivitis  gingiva is red from pregnancy

7.

Puberty Gingivitis

 swelling, bleeding, redness, someone going through puberty

8.

Gingival Hyperplasia



Use of anticonvulsant drug phenytoin (Dilantin) lead to chronic enlargement

of gingiva, no bleeding

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fluoride

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Recommended Daily Intake

0.05 - 0.07 mg/kg/day

Probable Toxic Dose5mg/kg fluorideCertain Lethal Dose32 - 64 mg/kg fluoride

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FLUORIDE INTAKE**

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DIETARY FLUORIDE SOURCES

Constituent

ppm / fluoride

fruit, milk, eggs

0.2 - 0.4

grains, vegetables

0.2 - 1.2

meat, poultry, fish fillet

0.8 - 1.4

canned fish (in oil w/bones)

4.0 - 12.0

tea (brewed)

1.0 - 3.0

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Fluoride gels and stannous

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55Self applied gels are available by Rx: 1.1% neutral sodium fluoride (5000 ppm fluoride) of 0.4% stannous fluoride (900 ppm fluoride)Stannous fluoride may cause some staining; it delivers less fluoride ion to the teethDelivery of fluoride gels is either by using a toothbrush or custom tray4 minutes of use in a custom tray is more effective than 1 minute of brushing with the gel since saliva quickly dilutes the gel removing contact with the teeth

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induce

vomiting

- often occurs spontaneouslyprotect stomach - milk, milk & raw eggs, lime watercalcium chloride or calcium gluconate administered both intravenously and orally

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ACUTE POISONING

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KIDNEYS AND FLUORIDE BALANCE

Fluoride ingested on an empty stomach produces peak plasma level within 30 minutes

Kidneys are important in maintaining fluoride balanceIndividuals with severe renal impairment can consume fluoridated water without ill effects provided they receive regular dialysis treatmentWater used for renal dialysis treated by reverse osmosiswww.dentalelle.com57

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Optimum levels

0.05

to 0.07 mg F/kg body weight/day “optimum” of fluoride intakeFluoride is beneficial in small amounts and toxic in higher amounts 5 to 10 g of single dose of sodium fluoride by an adult can result in death in 2 to 4 hours10 - 20 mg F ingested or inhaled daily 10 to 20 years by an adult can cause crippling skeletal fluorosis www.dentalelle.com58

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DEFLUORIDATION – what is it?

Process of

eliminating

excess fluoride naturally present in water supply

Community water fluoridation, a community preventive service, is measured by percentage of individuals served by public water systems containing optimally fluoridated

water

Optimal levels of fluoridation are achieved by adjusting fluoride to obtain a concentration between

0.7 and 1.2 ppm

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CARIES REDUCTION

Constant exposure to fluoridated water as well as other fluoride exposures will result in complete dental benefits

Maximum

benefit comes within

lifetime exposure

There is evidence that partial exposure in childhood reduces caries experience proportional to the length of exposure

Water fluoridation benefits lower socio-economic

areas relatively more than higher socio-economic

regions

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What is fluorosis?

A

hypo mineralized dental enamel caused by excessive ingestion of fluoride during tooth developmentSeverity of fluorosis depends on the amount of excess fluoride consumed over a period of time while teeth are developing, usually between ages 6 months to 6 yearsALSO MEANS, TEETH WITH FLUORISOS ARE LESS LIKELY TO HAVE DECAYOccurs in primary and permeant dentitionOnce teeth have erupted, fluorosis cannot developClinical appearance ranges from fine, lacy markings to white specks to severe pitting with heavily stained and friable enamelBrown stain results from the formation of stannous sulfide or brown oxide from the reaction of tin ion in fluoride compoundwww.dentalelle.com61

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fluorosis

Mild to moderate fluorosis

is associated with use of fluoride supplements, especially in higher socioeconomic groupsSwallowing or overenthusiastic use of fluoridated toothpaste by young children is a concernFruit juices and drinks with moderate to high concentrations of fluoride consumed by children may contribute to fluorosisInfant formula fluoride levels should be below 0.3ppmwww.dentalelle.com62

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Pro-fluoride

Fluoridation improves quality of

life and community water fluoridation is very cost effective (reaches a large population)Child will have less caries because their enamel is being demineralizedwww.dentalelle.com63

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DEAN’S FLUOROSIS INDEX

A conventional index used to assess dental fluorosis

One of the most universally accepted classifications for dental fluorosis

Each tooth present in an individual’s mouth is rated according to the following classifications known as:

6

- point ordinal scale

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Can a pregnant woman have fluoride?

Fluoride ingested by mother and crosses placenta and enters fetal circulation

Fetal plasma level is correlated with maternal level, however, it may be somewhat lower because fluoride is absorbed by skeleton and teeth of the fetusNo significant benefits of prenatal fluorideChildren received fluoridated water in utero and postnatal had less dental carieswww.dentalelle.com65

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Classifications of occlusion

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Class of occlusion

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profiles

Class I

(neutrocclusion) – NORMAL profileClass II (distocclusion)– Retrognathic profileDIVISION 1: mand. is retruded and max. incisors are “protruded” LABIOVERSIONDIVISION 2: mand. is retruded and max. incisors are “retruded” LINGUOVERSION Class III (mesiocclusion) – Prognathic profilewww.dentalelle.com68

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What is a crossbite?

When MAXILLARY teeth are LINGUAL to the mandibular teeth

This is because – in a normal dentition the MAXILLARY teeth should be BUCCAL to all mandibular teethSometimes only a few teeth are in cross bite (for example – 24/25 are in cross bite with 34/35)www.dentalelle.com69

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more

Edge to Edge

 incisal edges are edge to edge with each other, maxillary and mandibularOverjet  The “horizontal” distance between the mandibular incisors and the maxillary incisors, measured with a probe and in mmOverbite  The “vertical” distance by which the maxillary incisors overlap the mandibular incisors. Measured with a percentage

Openbite  Lack of incisal

contact and teeth

cannot be brought

together.

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Over jet (see how the anteriors overlap horizontally)

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Overbite (how the top front teeth overlap vertically)

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clefting

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Cleft lip and palate

Cleft lip and palate represent a failure of normal fusion of embryonic processes during development in 1st trimester of pregnancy

Formation of lip occurs between 4th and 7th week in uteroDevelopment of palate takes place during 8th to 12th weekFusion begins in premaxilla region and continues backward toward uvulaCleft lip - apparent by end of 2nd month in uteroCleft palate - evident by end of 3rd month in uteroOccurrence - 1 in 700 births www.dentalelle.com74

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treatment

Surgical union of cleft lip - before 6 months

Surgery to close palate - before 18 monthsObturatorOrthodonticsSpeech therapywww.dentalelle.com75