Cariology Lecture 3

What is epidemiology?

The study of the distribution and determinants of health

What are the two main types of epidemiology?

Descriptive and analytic.

What is the strategy of epidemiology?

Comparison between population groups.

What is prevalence?

The proportion of individuals with a disease in a population at a given point in time.

What is incidence?

The proportion or rate of new cases of a disease occurring in a population over a defined period of time.

What is a rate?

A proportion that includes a standardized denominator, often including a time element.

What does intensity measure?

The amount or severity of disease, such as number of teeth or surfaces affected.

Why is intensity important?

It provides more information than simple yes/no measures of disease presence.

What is an index?

A numerical value describing the relative status of a population on a graduated scale with upper and lower limits for comparison.

What are examples of dental caries indices?

DMF (Decayed, Missing, Filled), def (decayed, extracted, filled primary teeth), and RCI (Root Caries Index).

What are the characteristics of an ideal index?

Clarity, implicity, objectivity, validity, reliability, quantifiability, sensitivity, and acceptability.

What is the difference between reversible and irreversible indices?

Reversible: conditions like gingivitis or early caries; Irreversible: conditions like cavitated caries or periodontitis.

What is absolute change?

The numerical difference between two measurements.

What is percentage change?

The proportional difference between two measurements relative to the original value.

Give an example of absolute and percentage change.

If probing depth increases from 2.0 to 3.0 mm: absolute change = +1.0 mm; percentage change = 50%.

Why are both absolute and percentage changes important?

Absolute shows real magnitude; percentage shows proportional impact.

What are coronal caries?

Caries that occur on the crown of the tooth, affecting enamel and dentin.

What are the main types of coronal caries?

Smooth surface caries and pit-and-fissure caries.

Which surfaces are affected by smooth surface caries?

Interproximal (mesial, distal), facial, lingual, and occlusal/incisal

Which surfaces are affected by pit-and-fissure caries?

Occlusal, facial, and lingual pits

What are root caries?

Caries on exposed root surfaces, often facial, lingual, mesial, or distal.

Why do root caries increase with age?

Due to gingival recession and longer tooth retention.

What does the Root Caries Index (RCI) measure?

Proportion of root surfaces with caries among all root surfaces with recession.

What is the formula for RCI?

(Root caries surfaces ÷ Surfaces with recession) × 100.

How has coronal caries prevalence changed among U.S. children?

It has declined since the 1970s, particularly in school-aged children.

Which surfaces are most affected by coronal caries?

Pit-and-fissure surfaces, especially molars.

What percentage of caries in U.S. school children occur on pit-and-fissure surfaces?

Approximately 88%.

How have preschool caries rates changed?

Increased slightly in recent decades, especially among lower-income groups.

Why has the increase in preschool caries not indicated a new epidemic?

Because the rise is mostly due to more filled teeth, not more decay.

What trend is seen in adult and elderly caries?

Adult caries remain common, and root caries rates rise with age.

What percentage of adults 65+ have root caries?

About 63% with an average of 2.3 root surfaces affected per person.

What is the approximate annual incidence of caries in older adults?

About 1.2 surfaces per year (combined coronal and root).

How does caries incidence vary by age group in older adults?

Coronal and root increments per year are similar (~0.9 and 0.6 respectively).

What are the major causes of the decline in coronal caries in children in developed countries?

Fluoride exposure, dietary changes, improved oral hygiene, and public health measures.

What are the two main ways fluoride acts?

Pre-eruptively (systemic strengthens developing enamel) and post-eruptively (topical, enhances remineralization and inhibits bacteria).

List examples of pre-eruptive fluoride sources.

Water, supplements (drops, tablets), and unintentional ingestion from toothpaste.

List examples of post-eruptive fluoride sources.

Toothpaste, fluoridated water, rinses, gels, and varnishes.

What other factors have contributed to caries decline?

Antibiotics, salivary protection, microbiological shifts, and reduced sucrose intake.

What is the main difference between developed and developing countries in caries trends?

Developed countries show declines; developing countries show increases due to dietary westernization and less fluoride exposure.

What is the role of environmental vs. biological determinants in caries?

Environmental factors (diet, fluoride, hygiene) explain most differences, not genetics.

What does DMF stand for?

Decayed, Missing, and Filled (teeth or surfaces).

What does def stand for?

Decayed, indicated for extraction, and filled (primary teeth).

What is the importance of understanding both primary and permanent dentition in caries studies?

Because caries prevalence patterns differ by age and dentition, and combining them can mislead results.

Why can mean caries rates for ages 6–17 be misleading?

They combine low caries rates at younger ages with higher rates at older ages.

What are some challenges in measuring root caries?

Determining lesion origin, standardizing for recession, multiple surface lesions, filled abrasion, and tooth loss.

How do preventive programs impact caries rates?

Comprehensive programs (fluoride, sealants, education) reduce DMFS more effectively than education alone.

Why can adult caries incidence be equal to or greater than in children?

Adults retain more teeth longer, providing more surfaces at risk.

What is the overall epidemiological summary of dental caries?

Caries remains a concern for all ages, with declining coronal caries in children but increasing root caries in adults.

Eoidemiology

The study of the distribution of health, disease, and health behavior and their determinants and consequences in population groups

rate

a proportion using a standardized denominator

prevalence

the proportion with a disease in a population at a given point in time

incidence

the proportion of new cases of a disease in a population during a given period of time

intensity

refers to the amount of disease

usually in terms of number of teeth of surfaces affected

index

a numerical value describing the relative status of a population on a graduated scale

has definite upper and lower limits

what is index designed for

to permit and facilitate comparison

what are the characteristics of an ideal index

• clarity, or simplicity

• validity

• reliability (reproductivity)

• Quantifiability

• sensitivity (picks up small changes)

• acceptability

why is periodontitis considered non-reversible

loss of attachment or bone

types of changes

absolute

percentage

absolute change

actual = difference

original: 80000

final: 96000

absolute change: 16000

percentage change

original: 80000

final: 96000

absolute change: 16000

percent change: 16000/80000 = 20%

what surfaces can root caries be found

1. facial

2. lingual

3. mesial

4. distal

DMF (permanent dentition)

Decayed, Missing (due to decay), or Filled

def (primary dentition)

decayed, indicated for extraction, filled

RCI

root caries index

surfaces with root caries/surfaces with recession

examples of pre-eruptive fluoride

1. water

2. supplements (tablets and drops)

3. Dentifrice, gels, rinses

post-eruptive fluoride

1. dentifrice

2. water

3. gels, varnish

4. rinses

other factors that contribute to caries decline

1. antibiotics

2. salivary factors

3. microbiological factors

4. changing sugar sources (less sucrose)

the incidence of annual caries in older adults can be ____ than that of school aged children

equal to or greater than

primary dentition tooth caries has ______ more recently in the US

increased

average caries rates have _____ substantially in the US and most developed nations

decreased

are environmental factors (diet, fluoride, bacteria) or biological differences (race, ethnicity, geographical) more to blame for caries

environmental factors