1. Dental Caries

2. Introduction
Dental caries (tooth decay) is an infectious bacterial disease that has plagued human beings since the beginning of recorded history
Today, because of scientific advances and new technologies, dentistry is developing new strategies for managing dental caries
These strategies emphasize prevention and early intervention
What is covered by cariology? (Cariology includes the causes of caries, the process by which caries occurs, and the science and practice of caries management and prevention.)
Since the late nineteenth century, dentists have been fighting tooth decay by drilling out the decayed tooth structure and filling the tooth with a restorative material.

3. Bacterial Infection
Two specific groups of bacteria found in the mouth are responsible for dental caries:
Mutans streptococci (MS) (Streptococcus mutans) (strong disease causing)
Lactobacilli (LB)
They are found in relatively large numbers in dental plaque
The presence of lactobacilli in the mouth indicates a high sugar intake
Mutans streptococci are considered to be major pathogenic (disease producing) bacteria.

4. Transmission of Caries-Causing Bacteria
Mutans streptococci are transmitted through saliva, most frequently the mother’s, to the infant
When a mother has a high count of mutans streptococci in her mouth, the baby has a high count of the same bacteria in his or her mouth
Women should be certain that their own mouths are healthy
When the number of caries-causing bacteria in the mouth increases, the risk of dental caries also increases
How does a mother transmit her saliva, with its bacteria, to her infant? (It can be transmitted by kissing and touching the child after the mother’s hands have picked up bacteria from her mouth. Remember: No one advocates not kissing or touching babies; rather, the mother must be encouraged to keep her mouth healthy. This may include dietary counseling, professional cleanings, oral hygiene instruction, topical fluoride application, and removal of any caries. If necessary, an antibacterial, such as chlorhexidine, can be prescribed and placed in the mouth daily for about 2 weeks.)

5. Dental Plaque
Dental plaque is a colorless, soft, sticky coating that adheres to the teeth
Plaque remains attached to the tooth despite movement of the tongue, water rinsing, water spray, and less-than-thorough brushing
Formation of plaque on a tooth concentrates millions of microorganisms on that tooth
Many healthcare professionals are now stressing that plaque is a biofilm.
What is a biofilm? (Biofilms are composed of microbial communities that are attached to an environmental surface. These microorganisms usually encase themselves in an extracellular polysaccharide or slime matrix. Therefore plaque is an outstanding biofilm.)

6. Dental Plaque
Pictured: Dental plaque made visible with a disclosing agent.
Usually the patient rinses with or chews tablets of a nontoxic disclosing agent, and plaque is revealed as a red stain on the teeth. This stain is subsequently removed by brushing and flossing.
This is an easy aid to help patients look for areas they are missing in their daily oral care.
Care must be taken to cover areas of tooth-colored fillings with petroleum jelly to protect them. Areas of hardened plaque or tartar (calculus) will remain stained until they are removed professionally or wear off.
The tongue will also appear stained, but plaque forms on it, too, and needs to be gently brushed off.

7. Enamel Structure
Enamel is the most highly mineralized tissue in the body
It is stronger than bone
Enamel consists of microscopic crystals of hydroxyapatite arranged in structural layers or rods, also known as prism
The enamel crystals are surrounded by water
The water and protein components in the tooth are important because that is how the acids travel into the tooth, the minerals travel out, and the tooth structure dissolves
How mineralized is enamel? (Enamel is composed of 95% calcium minerals.)

8. The Caries Process
For caries to develop, three factors must be present at the same time:
A susceptible tooth
A diet rich in fermentable carbohydrates
Specific bacteria (regardless of other factors, caries cannot occur without bacteria)
Caries can also develop as a result of constant intake of acidic foods. This is called erosion.
What types of food or drink could be considered risky to the tooth because of their acid content? (This category could include soft drinks or lemon cough drops.)
If a patient only drinks diet soda rather than regular soda, does this have a positive effect on tooth health? (It does not. Acid breakdown of the tooth can occur with bacteria in the caries process or with acidic foods. Diet soda is more acidic than nondiet soda.)

10. Areas for Development of Caries
Pit-and-fissure caries occurs primarily on the occlusal surfaces and the buccal and lingual grooves of posterior teeth, as well as in the lingual pits of the maxillary incisors
Smooth surface caries occurs on intact enamel other than pits and fissures
Root surface caries occurs on any surface of the root
Secondary, or recurrent, caries occurs on the tooth surrounding a restoration
No surface is really safe from decay. Many patients believe that once a tooth has been restored, it cannot become decayed again. What type of decay can occur in these teeth? (Secondary or recurrent caries)

11. Stages of Caries Development
It usually takes some time, months to years, for a carious lesion to develop
Caries is an ongoing process characterized by alternating periods of demineralization and remineralization
Demineralization is the dissolution of the calcium and phosphate from the hydroxyapatite crystals
Remineralization is the redeposition of calcium and phosphate in previously demineralized areas
It is possible for the processes of demineralization and remineralization to occur without any loss of tooth structure
Minerals that are replaced during remineralization actually make the tooth stronger against acid attack than the original.
It is important to note that newly erupted teeth are especially vulnerable to acid attack because they have fewer minerals present at the surface (hypomineralization); this is similar to the exposure of roots, with their layers of less mineralized tissue.
What can be done in the dental office to help promote remineralization of teeth that are newly erupted? (Answers will vary.)

12. Demineralization and Remineralization
Pictured: Demineralization and remineralization of the tooth.
How can fluoride be provided to the patient to aid in remineralization? (It can be contained in water, toothpaste, and oral rinses. It can also be applied as a treatment at a dental office or used at home by the recommendation of the dentist.)

13. Stages of Caries Development
An incipient lesion (a watch) develops when caries begins to demineralize the enamel
An overt, or frank, lesion is characterized by cavitation (the development of a cavity or hole in the tooth)
Rampant caries describes the time between the onset of the incipient lesion and the development of the cavity; it is rapid and there are multiple lesions throughout the mouth
At what stage of caries development should the teeth be protected from demineralization? (Incipient)
At what stage does the patient usually first notice the lesion? (Overt or frank)
At what stage is it most difficult for the dentist to restore good health to the mouth? (Rampant)

14. Early Carious Lesion, or White Spot of Demineralization
The chalky white area in the photo is called the “white spot.” It is an area of decalcification, the earliest sign of decay. This is incipient caries.
How would it feel if a dental assistant went over this area with a dental instrument such as an explorer? (It would feel rough, an indication that the enamel structure has broken down.)
Is this lesion very painful to the patient? (There is generally no pain with this lesion other than sensitivity to sweet foods and hot and cold food and drinks.)
Courtesy Dr. John D.B. Featherstone, School of Dentistry, University of California San Francisco.

15. Courtesy Dr. Frank Hodges, Santa Rosa, CA.
Overt Carious Lesion
Where are the dental caries located in this patient’s mouth? (They appear as dark-stained areas between the anterior teeth and the areas in the pits and fissures of the posterior teeth that do not polish or scale off. Appearance is not always an exact way to diagnose caries.)
Are these early signs of decay? (Answers will vary.)
The occlusal surface that is decayed will “stick” when the dentist presses an explorer into the pits and fissures with a dental explorer to diagnose decay, but this method of examination is not as effective once the teeth have been exposed to fluoride.
Courtesy Dr. Frank Hodges, Santa Rosa, CA.

16. Courtesy Dr. Frank Hodges, Santa Rosa, CA.
Rampant Caries
What type of decay is in this patient’s mouth? (This is rampant decay. Multiple lesions are always present with this type of caries.)
Note that some of the carious lesions look as if they were prepared for restorations at one time. These lesions could also be considered secondary or recurrent caries.
How could this have happened to the patient? (Poor diet, poor dental care, or xerostomia [dry mouth])
Courtesy Dr. Frank Hodges, Santa Rosa, CA.

17. Severely Decayed Molar on a Child
This may be an example of “baby bottle” tooth decay, which is caused by frequent exposure of a child’s teeth for long periods to liquid that contains sugars. It can occur when a baby falls asleep with a bottle containing formula, milk, or juice; with the use of a pacifier dipped in honey; or even with breastfeeding.
Primary teeth have thinner layers of tooth tissue overlying the pulp, so they decay easily compared with thicker-layered permanent teeth.
The teeth most likely to be damaged are the maxillary anterior teeth. They are some of the first teeth to erupt and therefore are exposed the longest to the sugars in bottles.

18. Decay on the Lingual Surface of a Maxillary Lateral Incisor
What caused this lesion? (It could be due to the patient’s having a natural pit in this area of the tooth that was susceptible to the carious process.)
The dentist will use an explorer to visually check for any natural pits and fissures in the teeth or may use a laser device.
How can the patient protect natural pits and fissures from decay? (The patient can perform good oral hygiene, watch his or her diet, use fluoride products, and have the pits and fissures sealed in the dental office.)

19. Secondary (Recurrent) Caries
Form in the spaces between the teeth and margins of a restoration
Not easily seen, thus diagnosis is difficult
New restorative materials may prevent recurrent decay
Bacteria thrive in these areas, and radiographs are used to see this type of caries.
When dental restorations must be replaced, the reason is usually recurrent caries under the existing restoration.
Restorative materials that slowly release fluoride also can help to prevent secondary caries.

20. Root Caries
Occurs on the root of teeth that have gingival recession that exposes root surfaces
Becoming more prevalent and is a concern for members of the elderly population, who often have gingival recession, exposing the root surfaces
Older people often take medications known to reduce saliva flow, which contributes to caries
Carious lesions form more quickly on root surfaces than coronal caries does because the cementum on the root surface is softer than enamel and dentin
Like coronal caries, root caries has periods of demineralization and remineralization
People are living longer and keeping their teeth longer.
Reduced flow of saliva is a risk factor for the development of all types of caries.
Recession may be seen on an older person’s front teeth.
Why does the root surface become exposed? (Many factors are involved. Two of them are age and periodontal disease; others include hard brushing and tooth placement.)

21. Recurrent Decay
Pictured: Radiograph shows recurrent decay (arrows) under an amalgam restoration.
What indicates to the dentist that decay is present on this radiograph? (It is a dark area located interproximally, as indicated by the arrow. You can see that the radiograph must have good contrast to allow the dentist to see any carious lesions.)
Note that decay is often two times deeper and more widespread than it appears on radiographs. Therefore, using a radiograph alone is not the best way to diagnose decay, but a visual exam using an explorer would not show this lesion.
Would it be possible to see early decay on the occlusal surface on a radiograph? (No, only extensive decay of the occlusal surface on a radiograph would be seen.)

22. Root Surface Caries
Would these root carious lesions cause as much pain as other types of lesions already reviewed? (Usually root caries are slow to form and do not cause much pain until most of the tooth’s neck or cervix has been undermined. However, rampant decay can lead to extensive pain and suffering.)
Courtesy Dr. John D.B. Featherstone, School of Dentistry, University of California San Francisco.

23. Early Childhood Caries (ECC)
An infectious disease that can happen in any family
Many children live with the constant pain of decayed teeth and swollen gums
In some states ECC affects one third of preschool children
Tooth decay is the single most prevalent disease of childhood
Early childhood caries can be prevented with appropriate education of the parents and oral health care for the child
Because caries is an infectious disease, eventually it may be amenable to a vaccination.

24. Risk Factors for ECC
ECC is common among families of lower socioeconomic status
The rate of untreated dental disease among low-income children aged 2 to 5 years is almost five times higher than that seen in higher-income families
ECC is more common among:
Particular ethnic groups
In those families who have limited access to dental care
In areas where water fluoridation is lacking
ECC is also more common among children with special needs
The occurrence of ECC is disproportionately distributed in the United States.

25. How Children Get Early Childhood Caries
ECC is a transmissible disease
Bacteria in the parent’s or caregiver’s mouth are passed to the child
It is important for parents to keep their own teeth healthy to keep their children’s teeth healthy
Baby bottle tooth decay is another term for ECC
Bacteria from the parent or caregiver seed the baby’s mouth as teeth are erupting and colonize those areas. The descendants survive for the person’s entire life in competitive econiches, depending on food and availability of oxygen.

26. The Importance of Saliva
Physical protection involves a cleansing effect
Thick, or viscous, saliva is less effective than a more watery saliva in clearing carbohydrates
Chemical protection contains calcium, phosphate, and fluoride
Keeps calcium at the ready, to be used during remineralization
Chemical protection includes buffers, bicarbonate, phosphate, and small proteins that neutralize the acids after we ingest fermentable carbohydrates
Antibacterial substances in saliva work against the bacteria
If salivary function is reduced for any reason, the teeth are at increased risk for decay
Currently there are fluoride varnishes that are safer and easier to use than gels or foams because less systemic intake is required by the patient for remineralization.
New toothpastes, candies, and rinses incorporate this type of remineralization; however, they must be studied further in relationship to the overall processes occurring in the mouth.
New antibacterials are expected to become available in the form of rinses, gels, and varnishes.
What is another name for dry mouth? (Xerostomia)
What types of medications cause dry mouth? (Prescribed medications for high blood pressure, allergies, and mental anxiety)

27. Caries Diagnosis
The following methods are used to detect dental caries, and each has specific limitations:
Dental explorer
Radiographs
Visual appearance
Indicator dyes
Laser caries detector
Accurately diagnosing early dental caries is a challenge for the dentist.
What are the pros and cons to each method of caries detection?
(Dental explorers have limitations on the occlusal surface.
Radiographs may not be able to see early caries; the extent of caries damage may not be fully seen using radiographs.
Visual appearance isn't very reliable because teeth stains can be caused by a number of factors.
The indicator dyes change the color of teeth where decay has occurred. Some devices detect bacterial by-products and quantify sound signals to aid in caries detection; some detect differences in tooth structure and display the information on a screen.
Even the latest approach, the laser caries detector, has limitations. At the current level of technology, it cannot detect caries interproximally or under sealants or restorations, but it is useful in nonrestored areas and around the margins of restorations.)

28. Caries Detection Devices
Several types of devices have been developed that can provide a higher level of discrimination in the diagnosis of dental caries
Some detect bacterial by-products and quantify sound signals to aid in caries detection
Some detect differences in tooth structure and display information on a screen
Others have software that analyzes density changes on digital radiographs and outlines potential lesions
These are not routinely used in practice, but may be utilized with high-risk patients.

29. Laser Caries Detector
Used to diagnose caries and reveal bacterial activity under the enamel surface
Carious tooth structure is less dense and gives off a higher reading than noncarious tooth structure
The laser caries detector does not detect interproximal caries, subgingival caries, or secondary caries under crowns, inlays, or restorations.
An example of this is the DIAGNOdent.
When the laser beam passes through a change in the density of the tooth, it gives off a fluorescent light of different wavelengths. A clean, healthy tooth exhibits little or no fluorescence, resulting in very low readings.

30. Courtesy KaVo Dental, Charlotte, NC.
The DIAGNOdent
The DIAGNOdent directs a laser beam into the occlusal surface.
Courtesy KaVo Dental, Charlotte, NC.

31. Visual and Radiographic Appearance of Molar
As you can see, the molar appears intact but the readings from the laser tell another story. The readings indicate to the dentist that decalcification is occurring on the occlusal surface of this tooth.
The laser comes with a chart that helps the dentist determine what treatment needs to be performed on the tooth surface.
Courtesy KaVo Dental, Charlotte, NC.

32. Cross Section of Molar Showing Decay
The tooth must be clean for consistent readings to be obtained with the laser.
At the specific wavelength at which the laser operates, clean, healthy tooth structure exhibits little or no fluorescence, resulting in very low-scale readings on the display.
Carious tooth structure will exhibit fluorescence, proportionate to the degree of caries, resulting in increased scale readings on the display.
Courtesy KaVo Dental, Charlotte, NC.

33. CAMBRA Caries management by risk assessment
An evidence-based strategy for preventive and reparative care for early dental caries that can be used in any dental office
A dental health professional assesses an individual’s risk factors, and protective factors, then determines the level of risk for caries
An individualized preventive plan is developed based on the determined level of risk
Not all patients are equally prone to caries.

34. Methods of Caries Intervention
Fluoride: A variety of types are available to strengthen the tooth against solubility to acid
Antibacterial rinses: Products such as chlorhexidine rinses are effective
Decreased fermentable carbohydrates: Reduce the amount and frequency of ingestion
Increased salivary flow: Chewing sugarless gum—for example, one with a nonsugar sweetener such as xylitol
Patients can consider several risk interventions in the area of caries prevention, especially protection and remineralization.
It is important to note that preventive strategies are more effective when two or more are combined.

35. Preventive Measures Against Caries
A, Fluoride rinse.
B, Chlorhexidine rinse.
C, Xylitol gum.
Which of these preventive measures would be the easiest for the patient to use on a daily basis? (Sugar-free gum)
What is compliance? (The extent to which a patient follows the recommendations of a doctor or healthcare professional, particularly with respect to medication and other treatments)
Compliance with a preventive that does not taste good may be poor, so manufacturers try to provide rinses that have a pleasant taste.

36. Caries Risk Assessment Tests
Used to identify the factors that contribute to an increased risk for dental caries
If the patient’s risk for dental caries can be determined, it is possible to prevent the caries from developing by beginning appropriate preventive treatment
Risk-assessment tests for caries are based on the amount of mutans streptococci and lactobacilli present in the saliva
High bacterial counts indicate a high caries risk, and low counts indicate a low risk for caries
An example of a caries risk test is the saliva flow rate test. This test measures the amount of saliva in the mouth in milliliters per minute.
An important shift has taken place with regard to strategies for caries control because we now have the ability to promote remineralization and protection of the tooth surface.
Today the emphasis is on a prevention model and is moving away from a repair model.
Restoring the teeth does nothing to control caries.
What are some risk factors for future dental caries?
(History of dental caries
Presence of white spot lesions
Poor oral hygiene
High mutans streptococci count [test results]
Lower socioeconomic status
High daily consumption of sucrose)

37. Patients in Whom a Caries-Risk Test Is Indicated
New patients with signs of caries activity
Pregnant patients
Patients experiencing a sudden increase in the incidence of caries
Individuals taking medications that may affect the flow of saliva
Xerostomic patients
What is your caries risk? What factors can promote or even reduce the incidence of decay? (A dental professional should seek ways to take care of his or her own mouth as an example to the patients. Consider taking the caries-risk test.)

38. Patients in Whom a Caries-Risk Test Is Indicated
Patients about to undergo chemotherapy
Patients who frequently consume fermentable carbohydrates
Patients suffering from diseases of the autoimmune system
Chemotherapy often causes xerostomia.
Fermentable carbohydrates include fructose, or fruit sugar.
Autoimmune diseases include Hashimoto’s thyroiditis and lupus erythematosus.