Which of the following is true about enamel?
A. It has a blood and nerve supply.
B. It contains no pores.
C. It is comprised mostly of inorganic materials: 95% of it is calcium and phosphate ions combined to make up strong hydroxyapatite crystals.
D. Water makes up 12% of its composition.
How is the biological hydroxyapatite of tooth enamel different than pure hydroxyapatite?
A. It readily incorporates trace minerals, such as fluoride and carbonate into its crystal lattice.
B. It is stronger.
C. It has the following formula: Ca
12(PO 4) 8(OH )4
D. A and C
What differentiates dentin from enamel?
A. There are no significant differences.
B. Enamel can repair and regenerate, while dentin cannot.
C. Unlike enamel, dentin is living tissue with the ability for constant growth and repair, thanks to cells called odontoblasts that create new dentin.
D. Dentin is harder than enamel.
What acid is Streptococcus mutans capable of metabolizing, and in the process, further promoting demineralization?
A. lactic acid
B. acetic acid
C. pyruvate acid
D. formic acid
Which factors affect the rate at which acid is produced in plaque?
A. The microbial composition of the dental plaque.
B. The color of plaque.
C. The speed at which bacteria are able to metabolize the dietary carbohydrate.
D. The number of cavities present.
What prevents hydroxyapatite from continuously growing out of control?
A. Hydroxyapatite crystal growth-inhibitors in saliva.
B. p-rich proteins in saliva that coat enamel to prevent seeding by exposed crystals.
C. Fluoride prevents seeding by exposed crystals.
D. A and B
What is the effect of sucrose on interdental plaque ion stores?
A. Frequent sucrose exposure depletes calcium and phosphate reservoirs in plaque.
B. Sucrose increases calcium stores in interdental plaque.
C. Sucrose increases fluoride stores in interdental plaque.
D. Sucrose has little impact on calcium and phosphate reservoirs in plaque.
At what pH does tooth enamel begin to demineralize?
What is the clinical appearance of the initial stage of a carious lesion?
A. A large cavitation that extends into the dentin.
B. A chalky white and softened spot on the tooth surface.
C. Evidence of tooth erosion caused by acid attack.
D. Completely demineralized tissue.
How does Veillonella bacteria affect the process of demineralization/remineralization?
Veillonella use lactate as a substrate, metabolizing it to less acidic products, helping to create an environment that promotes remineralization.
Veillonella increases the acidity of plaque, increasing demineralization.
Veillonella causes xerostomia which increases demineralization.
Veillonella attacks pathogenic bacteria, promoting remineralization.
Which of the following is true about the remineralization of a carious lesion?
A. Deeper layers of enamel remineralize first and more fully.
B. Surface layers of enamel remineralize last and completely.
C. The lesion body in deeper layers of enamel does not remineralize because slow diffusion doesn’t allow supersaturation in deeper layers.
D. B and C
What is Ostwald ripening?
A. It is the name given to the maturing of bacteria in interdental plaque.
B. It is the name given to the maturing of dental enamel.
C. It is the name given to the process in which small, imperfect hydroxyapatite crystals re-form and grow to reach their maximum size in the presence of a large volume of saturated oral solution.
D. It is the name given to the regeneration of dentin.
What is the initial clinical appearance of a remineralized carious lesion?
A. It appears as a black cavitation.
B. It appears as a white scar with a shiny, hard surface.
C. It appears as a brown spot that feels soft and sticky with dental probing.
D. It appears as a white chalky soft spot that flakes with dental probing.
Which of the following is a remineralization-promoting characteristic of saliva?
A. Saliva stimulates odontoblasts to promote enamel remineralization.
B. Saliva does not promote remineralization.
C. Saliva is supersaturated with calcium and phosphate ions.
D. Saliva is slightly acidic, which helps to stimulate the remineralization process.
Which of the following is true about fluorapatite?
A. It is not very stable, making it more prone to demineralization.
B. It binds with calcium, making it less likely that calcium ions are pulled out of the tooth and into the solution.
C. It can change the critical pH level to 4.5.
D. B and C