Several factors contribute to the development of dental caries, some over which a patient has control; others are environmentally or genetically determined. Factors can be categorized into the following groups:

The acid-producing bacteria that cause dental caries, specifically, Streptococcus mutans

Quantity and quality of dental plaque (controlled by the level of home care). Plaque is a matrix of bacteria, bacterial products, food debris and other material that when left on a tooth creates an acidic environment conducive for the formation of caries.

Quantity and quality of saliva (buffering capacity). Saliva contains minerals that raise the pH in the oral cavity and help buffer the acid insult produced by cariogenic bacteria. Saliva also helps to physically wash the tooth surface.

Diet (fermentable carbohydrates): for every single sugar exposure, pH decreases for 20 minutes during which time the tooth surface becomes susceptible to acid attack.

Fluoride (from toothpaste, drinking water) chemically strengthens tooth structure making it more resistant to acid attack.

Xylitol and other products that can be prescribed to change the oral environment making it less susceptible to acid attack.

üThere is an environment that is conducive for disease progression

Advantages of the medical model:

It is more effective at treating and controlling disease

üIt sets the stage for disease prevention

üIt transfers OWNERSHIP of the disease to the patient

(Who assumes ownership in a surgical model?)

Return to Lesson 2

Caries Risk Assessment

ØWhat are the best predictors of future caries?

Plaque:

High plaque level is the primary risk factor for developing caries.

“Not all patients with plaque develop caries;

but patients with caries always have plaque.”

According to statistical models, evidence of past caries is the #1 predictor of future caries in adults

ØBacterial levels:

Presence of Strep mutans + Lactobacillis is a poor predictor of HIGH caries rate; but low levels are a good predictor of LOW risk.

üException: In infants, Strep mutans is a good predictor of future caries. Since the bacteria is transmissible, usually from the mother to the infant, one preventive strategy is to treat the parents at the same time that an infant is treated.

Contributing factors

•Diet – frequency and consistency of fermentable carbohydrates

•Fluoride exposure – during formative years and throughout life

•Saliva – flow rate and buffer capacity

•Other – age, socioeconomic status

How do you as a practitioner categorize a patient according to risk?

Example 1:

For pediatric patients

• No caries = low risk

• One lesion = high risk

For adults:

• No caries = low risk

•

• Combination of risk factors present plus

2 or more active lesions = high risk

Example 2: For adults

•Low = no risk factors and no lesions

(arrested lesion >3 yrs)

•Moderate = 1 risk factor and < 6 lesions

(including incipient caries)

•High = >6 active lesions

American Academy of Pediatric Dentistry Guidelines for Caries Risk Assessment of Infants, Children, and Adolescents

American Dental Hygienists Association Consensus Statement on Caries Management

Malmo University Department of Cariology

FACTOR	HIGH RISK	LOW RISK
Amount of plaque	Large amount of plaque on the teeth, meaning many bacteria that can produce acids (low pH, demineralization)	Few bacteria = "good" oral hygiene
Type of bacteria	Large proportion of "cariogenic" types of bacteria, resulting in lower pH and sticky plaque and also prolonged acid production	Low proportion of "cariogenic" types
Type of diet	High in carbohydrates, in particular sucrose; "sticky" diet leading to low pH longer time	Low sugar content; non- "sticky" type of diet
Frequency of carbohydrates	High sugar frequency resulting in longer time per day with low pH	Low sugar frequency
Saliva secretion	Reduced saliva flow leading to prolonged sugar clearance time and to a reduced amount of other saliva protective systems	Optimal, helps to wash out sugars and acids
Saliva buffer capacity	Low buffer capacity resulting in prolonged time with low pH	Optimal, time with low pH shorter
Fluorides	Absent: reduced remineralization	Available: increased remineralization

Treatment Strategies

Address the causative agent – change the oral flora using chemotherapeutic agents such as Chlorhexidine rinses that eliminate cariogenic bacteria and allow "normal" harmless bacteria to grow in its place.

Address the susceptible host – diet counseling, oral hygiene instruction. If someone IS a carrier of cariogenic bacteria, teach them how to limit the substrate (fermentable carbohydrates) used by the bacteria. Teach them why it is important to physically remove the bacterial colonies from the susceptible tooth surface.

Control the environmental factors – use fluoride, Xylitol, and other products to decrease the bacteria’s ability to destroy tooth structure

Transfer OWNERSHIP of the disease to the patient. EMPOWER him or her with the knowledge of how to control this entirely preventable disease!