Dental Caries Highlights
- Dental caries is the noncontagious bacterial disease. The initiation of a carious process is multifactorial including dietary habits, oral hygiene, etc.
- Caries play a key role in tooth loss, and the prevention of this deleterious disease is challenging. Both restorative and nonrestorative methods are applied in caries management.
- This chapter focuses on the role of bacteria in the caries process, the ways to diagnose early carious lesions, and prophylactic agents used in caries preventive measures.
Learners are expected to describe the:
Table of Contents
- The action of cariogenic bacteria.
- Chairside investigation of dental caries.
- Chemoprevention for dental caries.
Dental Caries Essay Questions
Question 1. Describe the mechanism of different caries preventive agents.
(or)
Briefly describe the chemoprophylactic agents for caries prevention.
Answer:
- Dental caries is a complex process with multifactorial etiological agents. All tooth surfaces are covered with a thin biofilm to which bacteria adhere and mature. These bacteria utilize dietary carbohydrates to produce acid which results in pH drop in the saliva and dissolution of the hydroxyapatite crystals.
- Preventive measures of dental caries include various mechanical and chemical measures.
Read And Learn More: Oral Medicine and Radiology Question And Answers
Fluoride:
- The use of fluoridated toothpaste, topical fluoride applicants, and pit and fissure sealants will prevent dental caries.
- Fluoride exerts an anti-cariogenic action by:
- Preventing tooth demineralization.
- Promoting remineralization of early carious lesions.
- Antibacterial effect on cariogenic bacteria.
- Fluoride is highly effective against smooth-surface caries but very minimal on pit and fissure caries.
Arginine:
- Arginine is an amino acid that occurs in food products and in saliva. It is metabolized by arginolytic bacteria and produces ammonia which increases the pH in the oral biofilm.
- This neutralizes the acidic environment and controls the growth of aciduric, cariogenic bacteria.
- It is added in fluoridated toothpaste for its additive effect on caries prevention.
Sugar Substitutes:
- Xylitol:
- Xylitol is a sugar alcohol, an artificial sweetener that cannot be fermented by cariogenic bacteria. Xylitol functions by effectively controlling plaque formation, bacterial colonization, and acid production thereby inhibiting enamel demineralization.
- It has a direct inhibitory effect on S. Mutans (Streptococcus mutans).
- Xylitol chewing gums and xylitol containing lozenges can be used for effective caries prevention. In children, xylitol tablets, and xylitol containing syrup can be used.
- Sorbitol: Sorbitol is another artificial- sweetener which can be fermented by oral microorganisms, but the rate of acid production is much slower than that of other dietary sugars and can be considered for caries prevention.
Probiotics:
- Probiotic was defined by Stillwell in 1965 as a substance secreted by one microorganism that promotes the growth of another microorganism.
- They are primarily bacteria. The live micro-organism is safe for consumption and has several beneficial effects. Probiotics develop a biofilm and protect the oral tissues. This biofilm, in turn, prevents the contact of pathogenic bacteria on oral tissues and teeth surfaces. In this way, probiotics compete with cariogenic bacteria.
- Yogurts with lactobacilli, probiotic cheese, and probiotic lozenges are used to reduce S. mutans colonization on regular consumption.
Novamin—containing Dentifrices:
- Novamin is a bioactive glass-ceramic material. They contain calcium sodium phosphosilicate as an active ingredient and release calcium and phosphate ions when exposed to aqueous media.
- Dentifrice containing 5% novamin and fluoride is effective in the remineralization of subsurface carious lesions. NovaMin also has an antibacterial effect.
Antibiotic Toothpaste: The presence of penicillin, triclosan or topical antibiotics like tyrothricin is an effective ingredient in destroying acidogenic bacteria and controlling caries progression.
Chlorhexidine Mouth Rinse:
- A 0.12% chlorhexidine is active against the cariogenic streptococci strains and thereby provides a bacteriostatic effect.
- Chlorhexidine also has a retention property in the plaque-coated enamel surface and can be released into the mouth after use.
Antimicrobial Peptides:
- Antimicrobial peptides exhibit a wide range of bactericidal effects. They act by binding to the bacterial membrane lipopolysaccharides.
- After binding, the peptides disrupt the cell membrane and kill the microbes by intracellular mechanisms.
Recent Advancements in Caries Prevention:
Casein phosphopeptide (CPP):
- Casein is a milk phosphoprotein and has cariostatic properties. Casein phosphopeptide is casein-derived amorphous calcium phosphate and is used in caries prevention for their remineralization property.
- CPPs stabilize calcium phosphate ions in solution and form an amorphous calcium phosphate (ACP) complex known as CPP-ACP. The CPP-ACP is taken up by dental biofilms and concentrated it on the enamel surface.
- Calcium, phosphate, and fluoride released from CPP-ACP, help to maintain the super-saturated state of these ions and assist remineralization.
Caries vaccines:
- Vaccine (monoclonal antibody) can control S. mutans colonization and prevent caries progression. Allergic reactions should be anticipated when considering nonhuman monoclonal antibodies.
- However, the concept is at the research level and needs a more clinical trial for effective implementation.
DNA recombination technology (replace¬ment therapy):
- Replacement therapy uses a harmless effector strain for permanent colonization in the host.
- This strain, in turn, will prevent the colonization of a specific pathogen.
- S. mutans strain BCS3-L1 is a genetically modified effector strain designed for replacement therapy to prevent dental caries.
Dental Caries Short Notes
Question 1. Write in brief about the caries conductive bacteria.
(or)
Write in brief about the cariogenic bacteria.
Answer:
- Cariogenic bacteria are those that are directly involved in dental caries disease (initiation and progression). Members of the Streptococci like S. mutans and S. sobrinus are important caries conduc¬tive bacteria.
- For the initiation of the carious process, these cariogenic bacteria should exhibit three properties:
- Ability to colonize on the tooth surface.
- Acidogenic—Producing acid from dietary carbohydrates.
- Aciduric—Ability to live in low salivary pH.
- S. mutans are more prone to initiate smooth surface caries by its plaque-forming tendency. The plaque on the smooth surface of teeth resists cleansing action and accumulates rapidly on the plaque-covered surface in the presence of dietary sucrose.
- S. mutans have an enzyme called glucosyl-transferases that split sucrose into units of glucose and fructose.
- Fructose is taken up by the bacteria and processed it for fermentation to produce lactic acid.
- The glucose units act as a bridge for new bacterial cells and consistently maintain plaque formation.
- After the caries initiation and initial destruction of the tooth take place by S. mutans, lactobacillus species like L. acidophilus continue the further destructive process of hard tissues. Lactobacillus is both acidogenic and acidophilic but lacks the attachment mechanism on plaque-covered tooth surfaces.
- The lactobacilli species present only in a highly acidic carious environment and in the presence of lactobacilli, S. mutans produce more acid from the sucrose and accelerate the caries progression.
Question 2. Discuss advanced chair-side diagnostic methods of dental caries.
Answer:
- Quantitative light fluorescence (QLF), also known as laser-induced fluorescence is used for enhanced visual inspection of dental caries. Laser light provides transillumination to recognize the demineralized zones in the carious lesion. LED laser devices apply a specific light wavelength to identify the demineralization spots.
- Once the demineralization zones are recognized, the LED displays a red color and produces an audible beep tone.
- Digital imaging fiber-optic transillumination (DIFOTI) is manufactured with a 655 nm diode and has high sensitivity and speci¬ficity for caries detection. This is a chair-side tool used by the dentist and has the benefit of identifying changes in the density of teeth at proximal surfaces.
- The device is calibrated to match the reflective index of the teeth of a particular patient by moving the camera throughout the patient’s mouth, and results are displayed by a two-digit numerical inference and audible report. This tool also helps to identify the early changes of occlusal pits and fissures.
- The spectra instrument is a caries illumination apparatus. The device uses a 405 nm blue-violet diode laser and an image-capturing mechanism, and analytic software. The device displays the zone of demineralization as a photograph of the tooth with varying color zones in the shades of green, blue, red, orange, and yellow. The images can be stored.
- Repeated examinations can demonstrate changes in the tooth, after initiating the preventive or therapeutic measures. The series of images helps to predict the caries progression or the effectiveness of remineralization therapy in arresting the caries process.
- The canary system uses laser luminescence and photothermal radiometry to identify carious lesions at a depth of 5 mm inside the tooth and to a size as small as 50 pm.
Question 3. Describe the caries risk assessment test.
Answer:
- The caries risk assessment test is carried out to identify the high-risk potential for caries development and for planning the preventive measures. The restorative treatment for the carious tooth only repairs the cavitations due to caries but never arrests the carious activity.
- Hence appropriate assessment-based activities are essential for risk factors elimination or modification to prevent caries progress apart from resto¬rative management.
- For caries-risk assessment, multiple, inter-linked factors should be considered for every individual patient like quantity, pH, buffering capacity, and sugar metabolism potential of the patient’s saliva.
- The chair-side investigatory methods include the quantitative assay of salivary lactic acid produced (LAP) by cariogenic bacteria in the oral cavity. The salivary sample is taken from the dorsum of the tongue.
Dental Caries Multiple Choice Questions
Question 1. The important caries conductive substance in our diet is.
- Glucose
- Sucrose
- Lactose
- Fructose
Answer: 2. Sucrose
Question 2. The expected incubation time for clinically detectable caries is.
- 6 months
- 10 months
- 2 years
- 6 years
Answer: 1. 6 months
Question 3. The reason for the loss of tooth structure due to dental caries is.
- Microbial colonization
- Alkaline pH
- Loss of mineral content
- Loss of blood supply
(Note: The reason for the loss of tooth structure due to dental caries is prolonged exposure to an acidic environment (low pH) and loss of mineral content).
Answer: 3. Loss of mineral content
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