Dental Caries Overview

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Questions and Answers

What type of biological molecules do dextrans belong to?

Nucleic acids

Lipids

Polysaccharides (correct)

Proteins

Which of the following is an example of bacteria associated with dextran production?

Streptococcus (correct)

Bacillus

Escherichia coli

Staphylococcus

Which of the following components is NOT an inorganic component mentioned?

Sodium

Glucose (correct)

Calcium

Fluoride

What type of organisms predominantly produce dextran?

Bacteria Signup and view all the answers

What is primarily responsible for the development of caries in teeth?

Saliva with sugar Signup and view all the answers

Which mineral component is associated with the inorganic category mentioned?

Phosphate Signup and view all the answers

Which of the following statements is true regarding carbohydrates and saliva?

Saliva contains negligible carbohydrates that impact dental health. Signup and view all the answers

Which dietary item was found NOT to contribute to caries in the experiment mentioned?

Meat Signup and view all the answers

What conclusion can be drawn about the relationship between carbohydrates and caries development?

Carbohydrates in the diet are a primary cause of caries. Signup and view all the answers

What role does saliva play in the context of carbohydrates and dental health?

It has a negligible amount of carbohydrates. Signup and view all the answers

What is the primary component of the dental plaque matrix by percentage?

Water Signup and view all the answers

Which of the following best describes the source of proteins found in the dental plaque matrix?

From saliva and bacteria Signup and view all the answers

In dental plaque, carbohydrates are predominantly found in which form?

Polysaccharides formed from bacteria Signup and view all the answers

Which of the following components is NOT part of the dental plaque matrix?

Mineral deposits Signup and view all the answers

Which statement about the composition of dental plaque is accurate?

The matrix contains approximately 80% water. Signup and view all the answers

What is a key characteristic of cariogenic bacteria?

Formation of acids Signup and view all the answers

Which of the following best describes aciduric bacteria?

Bacteria that can live and grow in acid Signup and view all the answers

Which two characteristics are mandatory for a bacterium to be considered cariogenic?

Formation of acids and growth in acidic environments Signup and view all the answers

What role do cariogenic bacteria play in the development of dental caries?

They produce acids that demineralize tooth enamel Signup and view all the answers

Which of the following statements is true regarding the characteristics of cariogenic bacteria?

They can thrive in acidic environments Signup and view all the answers

What is the primary role of Streptococcus mutans in dental health?

It produces adhesive, insoluble plaque. Signup and view all the answers

Which substance does Streptococcus mutans polymerize to create a sticky plaque?

Sucrose Signup and view all the answers

What characteristic of dextran contributes to its role in dental plaque formation?

It is an insoluble and sticky substance. Signup and view all the answers

What initiates caries on smooth tooth surfaces according to the properties of Streptococcus mutans?

The high molecular weight polysaccharide (dextran) enabling adherence. Signup and view all the answers

What is the composition of the plaque formed by Streptococcus mutans made from sucrose?

High molecular weight polysaccharides. Signup and view all the answers

What is the pH level of plaque in caries-free individuals?

7.1 Signup and view all the answers

What is the pH of plaque in individuals with extreme caries?

5.5 Signup and view all the answers

Which of the following is a function of saliva in relation to dental health?

Formation of pellicle from salivary glycoprotein Signup and view all the answers

What effect does saliva have that contributes to preventing dental caries?

Washing effect Signup and view all the answers

Which statement best describes the relationship between plaque pH and dental caries?

Caries-free individuals maintain higher plaque pH levels. Signup and view all the answers

Study Notes

Dental Caries

Dental caries is a progressive, irreversible microbial disease of calcified dental tissues.
It's characterized by demineralization of inorganic tissue and destruction of organic tissue.
It's the most prevalent chronic disease affecting humans.
Its effects persist throughout life, even after treatment.
It affects both sexes and all races, social-economic backgrounds, and age groups.

Requirements for Dental Caries Development

Development requires specific conditions occurring simultaneously.
A susceptible tooth is necessary.
A diet rich in fermentable carbohydrates is essential.
Specific types of bacteria are required.
Dental plaque is involved.
Time is a factor in the process.

Contributing Factors in Dental Caries

Tooth

Tooth composition (fluoride content) influences resistance to caries.
Tooth morphology (deep pits) predisposes to caries development.
Tooth malalignment can increase caries risk.

Saliva

Saliva composition with higher ammonia content can offer caries resistance.
Low saliva pH promotes caries development.
Xerostomia (decreased saliva flow) increases caries risk.
Thick saliva can increase caries risk.
Antibacterial factors in saliva play a role in caries prevention.

Diet

Refined foods tend to promote caries.
High carbohydrate content promotes caries.
Vitamins D, K, and B6 can reduce caries risk.
Fluoride content in the diet influences caries development.

Etiology of Dental Caries

No single, universally accepted theory explains etiology.
Several theories have been proposed.
- Acidogenic theory (Miller's chemico-parasitic theory)
- Proteolytic theory
- Proteolysis-Chelation theory

Acidogenic Theory (Miller's Chemico-Parasitic Theory)

Dental caries is a two-stage process.
- Decalcification of calcified parts.
- Dissolution of residue.
Acid is formed from sugar fermentation in retained areas of the teeth.

Acidogenic Theory (Mechanisms)

Acidogenic bacteria and carbohydrates produce acid.
Acid demineralizes tooth enamel and dentin.
Proteolytic bacteria digest organic materials.

Role of Carbohydrates

Tooth incubated with saliva and sugar leads to caries.
Tooth incubated with saliva and meat does not develop caries.
Dietary carbohydrates are the primary source because saliva contains insignificant amounts.
Monosaccharides promote more caries due to ease of breakdown and quick diffusion into plaque.
Increased carbohydrate intake correlates with increased caries activity.
Frequent carbohydrate intake between meals increases caries activity.
Sticky carbohydrates remain attached to teeth, increasing caries risk.

Role of Microorganisms

Microorganisms are necessary for caries development.
Saliva with carbohydrates and no microorganisms prevent caries.

Cariogenic Bacteria

Acidogenic bacteria produce acid.
Aciduric bacteria can thrive in acidic environments.
Extra-cellular polysaccharide production leads to plaque formation.

Streptococcus Mutans

A key acidogenic bacterium in early stages of dental caries.
Strongly acidogenic and produces acid at low pH levels
Can mutate from round to rod shape in varying pH.
Dextran production enables bacterial adhesion to teeth.

Lactobacilli

Isolated from late-stage dental caries.
Some bacteria are involved in initiating caries, and others in its progression.
Other streptococci, such as Streptococcus sanguinis and Actinomyces, play roles in root surface caries (but not enamel caries).

Role of Acid

Formed by enzymatic breakdown of carbohydrates by bacteria.
Lactic acid is a common type of acid formed.
Butyric acid can also potentially form.
Enamel dissolves when the pH drops below 5.5.
Acids need to be retained on tooth surfaces for extended periods, which plaque aids.

Role of Dental Plaque

A tenacious, bacterial structure.
Soft and unmineralized.
Forms on inadequately cleaned teeth.
Removable with tooth brushing.

Mechanism of Plaque Formation

Initial deposition of a cell-free layer (acquired pellicle) consisting of salivary glycoproteins.
Colonization of the pellicle by bacteria.
Plaque maturation through further colonization.

Composition of Dental Plaque

Contains water (80%), proteins (from saliva), carbohydrates (like dextran), lipids (bacterial origin), and inorganic components (calcium, phosphate, potassium, magnesium, fluoride).
Specific types of bacteria, such as Streptococcus, filamentous bacteria, and lactobacilli are part of dental plaque.

Role of Plaque Matrix

Acts as a diffusion barrier, retaining acid in high concentrations.
Slows down buffer entry from saliva.
Contributes to plaque adhesiveness.

Role of Saliva in Dental Caries

Saliva forms the pellicle (initial layer).
Saliva provides a rinsing effect (xerostomia increases incidence).
Saliva has buffering capacity (bicarbonates, phosphates).
Saliva contains antibodies that kill microorganisms.
An antibacterial substance like lysozyme, peroxidase, and lactoferrin are also present.

Proteolytic Theory

Microorganisms invade the organic areas in enamel as well as destroying inorganic part and producing acids.
This acid demineralizes the inorganic areas of the enamel.

Proteolysis-Chelation Theory

Chelation is the complexing of metal ions.
Metal ions complexing promotes stability. (chlorophyll and hemoglobin are examples).
This theory involves bacterial attack on the organic parts of the enamel, complexing the organic, and producing acids from the calcium ions.
This theory suggests enamel caries can start from organic or inorganic materials.

High-Risk Patients for Caries

Patients undergoing chemotherapy
Patients who frequently consume fermentable carbohydrates
Individuals with autoimmune diseases.
Pregnant people
Those taking medications impacting saliva flow

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Description

Explore the significant aspects of dental caries, including its definition, development requirements, and contributing factors. This quiz covers key knowledge on how dental caries affects individuals of all demographics and the necessary conditions for its onset.