Current Concepts in Caries Risk Assessment
DR P. MARAZZI/SCIENCE PHOTO LIBRARY
Staying abreast of the changing landscape of caries risk assessment, management, and prevention will help oral health professionals provide the highest quality patient care.
By Martha McComas, RDH, MS
After reading this course, the participant should be able to:
1. Describe the caries disease process.
2. Identify the components of caries management by risk assessment.
3. Discuss strategies for preventing and managing caries.
Dental caries is defined as a dissolution of enamel due to chemical
byproducts produced by acidogenic bacteria during the fermentation of dietary
sugars or carbohydrates.1,2 These bacterial byproducts, or
exotoxins, are highly acidic and create an environment in which acidogenic and
acidophilic bacteria are capable of flourishing. The progression of dental
caries occurs over time where hard tissue is continually demineralized. When
demineralization is allowed to progress without intervention, the tooth
structure is dramatically changed. These changes lead to visible or
undetectable holes in the enamel surface, also known as cavitation.1,2
The body combats this acidic environment with the help of saliva, which
has a natural buffering/neutralizing capacity.2 The introduction of
saliva results in a more basic pH level where cariogenic bacteria do not
thrive. If an acidic pH is sustained, however, a metabolic shift occurs,
resulting in caries lesion formation and progression.2 This shift
can occur due to the frequency, quantity, and type of sugars consumed, from
lack of regular or effective biofilm removal, and from decreased saliva
secretion.2 When simple sugars and fermentable carbohydrates are
regularly consumed, the oral environment never returns to a neutral state,
where remineralization of enamel can take place.
Biofilm is defined as a matrix of bacteria, their byproducts, and sugars
from the diet. It can be disrupted and or removed by mechanical intervention
(eg, brushing/flossing). If left undisturbed, the biofilm becomes home to
acid-producing bacteria that proliferate. Soon, enamel demineralization
predominates, with the consequence being active caries. Poor biofilm removal
may be why 42% of children in the United States between the ages of 2 and 11
have dental caries in their primary dentition.3 However, even in a
fairly clean mouth, minerals of the enamel are continuously lost and gained. In
fact, even in the absence of a clinically visible lesion, demineralization
still may occur.2
Saliva's role in the remineralization process is best seen in patients
with hyposalivation, otherwise known as xerostomia. Xerostomia can be the
result of medication use, medical treatment, illness, or medical conditions
that slow down or arrest saliva production. Because saliva plays a main role in
the buffering process after an acid attack, a lack of saliva can lead to an
altered oral microflora. The results of this altered environment often lead to
dental caries on both enamel and cementum surfaces.2
Modern caries management should focus on the following objectives:
decrease the amount and frequency of fermentable carbohydrates in the diet;
encourage regular and effective removal of biofilm from the tooth surface;
implement caries management by risk assessment (CAMBRA), including the
assessment of saliva production; increase the application of professional and
over-the-counter sources of topical fluoride in both adults and children; and
encourage the placement of dental sealants.
Caries can be
primary, with lesions that have developed on intact tooth surfaces, or
secondary, with lesions that have developed adjacent to existing restorations.2,4
In addition to primary and secondary lesions, residual lesions are classified
by any amount of outstanding demineralized dentin.2 More important,
caries lesions are classified by whether cavitation exists.1,2 Visual
examination, both clinically and radiographically, should be the primary method
for caries detection. The use of a sharp-tipped instrument, such as an
explorer, can create an opening on demineralized surfaces, causing inadvertent
A noncavitated lesion is typically limited to demineralization of the
subsurface of the tooth where the outer layer of tooth structure is without
fracture. These lesions are commonly referred to as white spot lesions, but may
appear yellow or brown as the lesion picks up stains from the diet. When the
tooth is dried, a brighter more opalescent lesion may appear. These lesions are
a more advanced form of noncavitated lesions. They can still be arrested with
the use of topical fluorides. Both of the above-mentioned lesions do not
exhibit breaks in the tooth structure and are considered noncavitated. However,
either one can be in a state of activity or rest. These types of lesions
require attentiveness, careful judgment, and increased preventive measures to
eliminate the chance of progression.
Cavitated lesions display breaks in the surface of enamel or cementum,
perhaps exposing the dentin.1 In many cases, demineralization is so
significant, the lesion is visible on a radiograph. At this stage, mechanical
intervention may be necessary. The management of dental caries should be based
on performing the least invasive treatment required to help restore a balanced
oral environment.1 The decision to restore lesions vs remineralize
lesions should be based on the patient's risk factors through CAMBRA.1
CAMBRA is an
essential part of caries management.5,6 Clinical or radiographic lesions
are a historical representation of disease activity. This means current disease
activity is difficult to determine, just as future disease activity is
challenging to predict. However, extensive evidence has identified key
determinants that can predict caries risk. These risk factors are poor or
ineffective oral hygiene, existing restorations and/or caries lesions,
xerostomia, smoking, and frequency of carbohydrate consumption. Caries
management and prevention methods for high-risk patients should be individualized
to meet their unique needs. Using a standard way of identifying caries risk is
important so that all team members are aware of the management and prevention
Many CAMBRA forms are available. The American Dental Association (ADA),
American Academy of Pediatric Dentistry, and California Dental Association all
have forms for office use. They encourage the management of caries before the
lesion exists and agree that the best predictor of future disease is based on
patients' 3-year caries history and current dietary habits. Each group bases
its preventive guidelines on a destructive vs protective factor balancing act,
meaning the advancement or reversal of dental caries is highly dependent on the
balance or imbalance between protective factors and destructive factors.5
New technologies are available that can support standardization of caries
risk assessment. For example, an app developed by researchers at the University
of California, San Francisco, brings caries risk assessment, planning, and
high caries risk should undergo a diet analysis as part of a caries management
and prevention program.2 A diet analysis is typically a two-part
procedure involving the patient and the clinician. The patient journals the
foods he or she consumes over 3 days to 4 days, along with day and time of
intake. At a subsequent appointment, the dental hygienist and the patient
review the journal and investigate some reasons for dental decay. Once a decay
source is identified, the patient and dental hygienist can formulate a plan of
action on the best way to manage and prevent future caries. This plan may
include restorations, dental sealants, increased oral hygiene procedures,
saliva substitutes, or topical fluorides. The plan should be revisited at each
recare appointment and adjusted according to the patients' risk and needs.2
Patients contribute to the daily removal of biofilm through oral hygiene
measures. Dental biofilm is extremely diverse in its structure and composition.
If the biofilm advances in structure due to ineffective removal, many varieties
of prokaryotes will grow and populate, excreting an acidic exotoxin. This
acidic exotoxin demineralizes the tooth structure.
Saliva is a naturally occurring protective feature of the oral
environment and increased caries incidence is often seen in adults with
hyposalivation. Patients with dry mouth should avoid consuming sugary foods and
drinks. Patients should be instructed on optimal oral hygiene, sip water
frequently, and receive a professional fluoride varnish every 3 months.2
Normal salivary flow rates are 0.3 prokaryotes to 0.5 ml/min unstimulated
and 1 prokaryotes to 3ml/min when stimulated. A simple salivary flow assessment
can be performed by the dental hygienist. Patients should be asked to avoid
eating or drinking 30 minutes prior to saliva collection. In an upright seated
position, the patient should spit into a disposable cup for 1 minute. Then the
saliva is collected into a disposable graduated syringe for measurement. Saliva
flow should be documented into the record. It may be difficult to collect
saliva samples from patients with xerostomia, as their saliva may be foamy. If
this is the case, saliva flow may need to be stimulated, such as having the
patient chew on a piece of wax for 5 minutes before expectorating.
FIGURE 1. Too much fluoride during tooth development can lead to dental fluorosis,
which causes brown staining of the teeth.
DR P. MARAZZI/SCIENCE PHOTO LIBRARY
For many years, fluoride was thought to be most effective when ingested
systemically. It was theorized that the fluoride ion was most effective at the
site of amelogenesis, when the enamel and dentin were still in formation.1,8
Although effective, too much fluoride during tooth development can lead
to dental fluorosis (Figure 1). Fluoride maintains a presence in the
saliva during the demineralizationremineralization processes.2 In
fact, the quantity and efficacy of the actual fluoride ion that is available
before, during, and after brushing and rinsing are key.8 Researchers
and manufacturers are currently working on a new family of toothpastes and
mouthrinses that use chemical release strategies to maximize the
bioavailability of fluoride ions in the saliva.8 As such, patients
at high caries risk should be given customized oral hygiene instruction
focusing on effective brushing techniques with a dentifrice that contains 1,000
ppm to 5,000 ppm fluoride for daily at-home use.2,9
Fluoride toothpaste should be used with the eruption of the first tooth.8,10–12
For children age 0 to 2, the US Department of Health and Human Services and ADA
Council on Scientific Affairs recommend using a "smear" (approximately 0.1 mg
of fluoride or 0.1 g toothpaste) of fluoride toothpaste containing no less than
500 ppm of fluoride.8,11,12 Patients age 2 to 6 should use a
pea-sized amount of toothpaste that contains 0.25 mg fluoride two times per
day.8,11,12 A metaanalysis of the literature, however, determined
that regardless of age, children using fluoride toothpaste should be supervised
by a parent in order to prevent overconsumption.8,9,12,13
Recent systematic reviews of topical fluoride use for the management and
prevention of dental caries report children and adolescents age 6 to 18 should
use a weekly mouthrinse of 0.09% fluoride (900 ppm).8,14
Additionally, patients at high risk for enamel caries or root caries, such as
those with existing restorations and/or active caries lesions, should receive
professionally applied fluoride varnish at regular 3-month to 6-month
intervals.8,10,14,15 Individuals at high caries risk need close
monitoring of oral hygiene habits and increased topical application of fluoride
varnishes (50,000 ppm NaF/22,600 ppm F).8,14 In addition to managing
caries in permanent teeth, the US Preventive Services Task Force recommends
that primary care clinicians apply professional fluoride varnish on all erupted
primary teeth of infants and children.15
In the early years of community water fluoridation, notable decreases
(about 50%) in decayed, missing, and filled teeth were seen in areas with water
fluoridation. When fluoridated water is consumed, a low amount of fluoride is
absorbed by the biofilm that adheres to enamel surfaces. Nearly 75% of the
systemic intake of fluoride in the US comes from the water and processed foods.16
Since 2011, the federal guidelines on community water fluoridation recommend
0.7 ppm in all communities. Currently, approximately 10 million people live in
areas that have naturally occurring fluoride in their drinking water.17
Years of water fluoridation have lead to an increase in the fluoride found in
processed foods and beverages, including baby formula. Therefore, fluoride
supplements should be limited to children who live in areas where they consume
water containing less than 0.6 ppm. In addition, fluoride supplements should be
adjusted based on age.17
In the fall of 2014, the US Food and Drug Administration (FDA) approved
the use of silver diamine fluoride (SDF) to treat dentinal hypersensitivity.
Until December 2016, when the FDA noted SDF 38% as a "Breakthrough Therapy
Designation" for the arrest of dental caries, SDF was used off-label to prevent
cavitation. It is available as a 38% solution that contains 24.4% to 28.8%
(w/v) silver and 5.0% to 5.9% fluoride (44,800 ppm) in a basic form (pH of 10).18
Clinical studies demonstrate that SDF is a safe, effective, and economical
preventive product. SDF not only aids in the prevention of caries, but it also
helps arrest active cavitated lesions. SDF is effective in low but frequent
doses, and does not require that all demineralized dentin be fully removed.19–21
In addition, silver ions are bactericidal and interfere with new biofilm
SDF is recommended to treat patients at extremely high caries risk;
caries lesions that are difficult to treat (distal of the third molars);
patients whose behaviors or medical conditions make dental treatment difficult;
patients with multiple active caries lesions that cannot be treated in a single
visit; and individuals living in areas with few dental providers.18
SDF is contraindicated in patients with a silver allergy or ulcerative
gingivitis/stomatitis. Adverse side effects of SDF include darkening of the
demineralized enamel as the SDF forms a tough, impervious layer on the tooth.19
For best results, the areas of active cavitated lesions should be dried then
swabbed with a microbrush containing 38% SDF once per week for 3 weeks.19–21
The success of SDF in caries arrest is dependent on repeat applications
over multiple years and dryness of the lesion during application. Reviews have
indicated that longer application time does not improve the outcome, but it
does decrease the need for a post-treatment rinse due to the increased amount
of absorption.19 Patients need to understand that multiple
applications are necessary and that permanent enamel staining is likely.18
FIGURE 2. The use of resin-based dental sealants or
glass-ionomer based sealants can prevent and arrest
caries in the pits and fissures.
Not all areas on the tooth can be maintained by brushing or flossing
alone. The occlusal surfaces of teeth contain deep pits and fissures that are
too small in width for a toothbrush to effectively clean. For patients with
noncavitated lesions, the use of resin-based dental sealants or glass-ionomer
based sealants can prevent and arrest caries in the pits and fissures (Figure
Dental sealants are recommended by the ADA and the Centers for Disease
Control and Prevention for the prevention of dental caries in sound teeth. Up
to 80% of caries can be prevented through the use of dental sealants.25
Sealants are effective in reducing lesion progression from noncavitated to
cavitated.26,27 In 2001, an independent task force reviewed several
school-based sealant programs and found that children with sealants had a 60%
decrease in overall caries development.26 In addition, literature
reviews have concluded that teeth with partial or complete loss of sealants are
not at any higher risk for future caries development as compared to teeth that
had never received sealants at all.28 Therefore, dental sealants
should be a form of caries prevention for children and adolescents who have
permanent molars erupting.28
Dental hygienists should stay abreast of the changing landscape of caries
risk assessment, management, and prevention measures. From educating patients
on effective oral hygiene and healthy nutrition, to knowing how to balance the
use of systemic and topical fluorides, it is possible to provide the most
up-to-date and effective methods of dental caries management and prevention.
The author would like to thank Sheree Duff,
RDH, MS, for her help with this manuscript.
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- Kidd E, Fejerskov O. Essentials of Dental Caries. Oxford,
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- National Institute of Dental and Craniofacial Research. Dental caries
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- Carey CM. Focus on fluorides: update on the use of fluoride for the
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- Mattana DJ, Relich EE. Fluorides. In Wilkins EM. Clinical Practice
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- American Dental Association Council on Scientific Affairs. Fluoride
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- Scottish Intercollegiate Guidelines Network. Prevention and
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- Weyant RJ. Topical fluoride for caries prevention: executive summary
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- Horst JA, Ellenikiotis H, Milgrom PL. UCSF protocol for caries arrest
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- Mei ML, Lo EC, Chun-Hung Chu BD. Clinical use of silver diamine
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- Ahovuo-Saloranta A, Hiiri A, Nordblad A, Mäkelä M, Worthington HV.
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- Griffin SO, Oong E, Kohn W, et al. The effectiveness of sealants in
managing caries lesions. J Dent Res. 2008;87:169–174.
- Oong EM, Griffin SO, Kohn WG, Gooch BF, Caufield PW. The effect of
dental sealants on bacteria levels in caries lesions: a review of the evidence. J Am Dent Assoc. 2008;139:271–278.
- Centers for Disease Control. Dental sealants prevent cavities.
Available at: cdc.gov/vitalsigns/dental-sealants/index.html. Accessed December
- Gooch BF, Griffin SO, Gray SK, et al. Preventing dental caries
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- Beauchamp J, Caufield PW, Crall JJ, et al. Evidence-based clinical
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- Griffin SO, Gray SK, Malvitz DM, Gooch BF. Caries risk in formerly
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From Dimensions of Dental Hygiene. January 2017;15(1):42-44,47.