Ch 7 Dental Materials

Prevention/ Preventative Aids

chemicals, devices, or procedures that reduce or eliminate disease or tooth destruction in the oral cavity.

Fluoride

naturally occuring mineral that helps protect tooth structure from dental caries.

Fluorisis

enamel condition caused by consumption of excessive levels of fluoride.

Demineralization

action that removes mineral from the tooth, usually causeb by acids.

Dental Caries

a disease process whereby bacteria in plaque metabolize carbohydrates and produce acids that remove minerals from teeth and permit bacteria to invade the tooth and do further damage.

Fluorapatiite

tooth mineral thats results when fluoride is incorporated into the tooth.

Cariogenic

substances or microorganisms that promote dental caries.

Erosion

loss of tooth mineral caused by dietary or gastric acids, not by bacterial metabolism (caries process).

Antibacterial Mouth Rinse

liquid used to rinse the oral cavity to reduce or suppress bacteria associated with dental caries or periodontal disease.

Substantivity

property of a material to have a prolonged therapeutic effect after its initial use.

Over-the-counter (OTC)

available in retail or drug stores without a doctors prescription.

Sealant

a protective resin that is bonded to enamel to protect pits and fissures from dental caries.

Desensitizing Agent

a chemical that seals open dentinal tubules in order to reduce tooth sensitivity to air, sweets, and temperature changes.

Mouth guard

a hard or pliable material that protects teeth from trauma during sports activities or as the result of teeth grinding.

Custom-made

made specifically to fit one individual.

Bleaching

a cosmetic process that uses chemicals to remove discolorations from teeth or to lighten them.

Extrinsic stains

stains occurring on the tooth surface.

Intrinsic stains

stains that are incorporated into the tooth structure, usually during the tooth's development.

What is the acceptable optimal level of fluoride in drinking water?

0.7 to 1.2 mg/L or parts per million (ppm)

What is clinical evidence of severe fluorosis?

Brown staining and pitting.

Fluorosis is usually found where there is high levels (more than 2 ppm) of fluoride that occurs naturally in drinking water. (T/F)

True

What is clinical evidence of mild or moderate fluorosis?

opaque white spots or bands on the teeth.

Causes of fluorosis:

-high concentrations of fluoride in drinking water.
-excess fluoride toothpaste swallowed by a child.
-other iatrogeneic (doctor-induced) factors-- dr. overly prescribing fluoride drops or lozenges.
*all of this occuring during formation of teeth.

What is the first step to the caries process?

demineralization

According to studies, what is the greatest anti-caries approach?

From topical fluoride exposure after the teeth have erupted. Fluoride in the saliva surrounding the tooth encourages remineralization.
*previously it was thought that fluoride in drinking water in developing teeth was the best approach.

Tooth mineral dissolves at what pH?

5.5 (acidic)
when mineral is converted to fluorapatite, the pH at which it dissoves is lowered to 4.5. (more acidic)

Fluoride from drinking water and toothpastes, mouth rinses, and some foods remain in the saliva for for several hours and has a prolonged topical effect on teeth? (T/F)

True

Causes of erosion:

-Highly acidic foods and beverages (citrus fruits, sodas, and wine).
-Medical conditions that cause stomach acid to enter the mouth (acid reflux, bulimia, anorexia)

Fluoride does not provide protection against erosion. (T/F)

False
Fluoride provides some degree of protection against erosion, but repeated acid attacks will overcome the beneficial effects of fluoride.

Studies have shown that fluoride alone is not as effective as when used in conjunction with an antibacterial mouth rinse. (T/F)

True

Therapeutic mouth rinses can be used to replace daily mechanical plaque removal (tooth brushing/flossing)? (T/F)

False

Chlorhexidine gluconate

-a bis-bisguanide that is effective against a broad spectrum of microorganisms.
-a prescription mouth rinse that is avaliable commercially through several companies.
- common trade names are Peridex, Perigard, Oris CHX.
-one of the most effective agents f

What is the maximun concentration of Chlorhexidine gluconate that is allowed by the FDA in the U.S. ?

0.12%

When is the antibacterial effects the greatest in Chlorhexidine gluconate?

For several hours after use, but it may last for few days.

What is the recommended rinsing regimen for Chlorhexidine gluconate that was suggested by the organization of western U.S. dental school?

Rinse nightly for 1 minute with approximately 10 ml of 0.12% of Chlorhexidine for 1 week each month until the dentist tells you to discontinue use.

SIde effects and disadvantages of Chlorhexidine gluconate:

-formation of brown stains on the teeth and tongue, glass ionomers, compomers, composit restorations, and artificial teeth.
-has a bitter taste and may effect the taste of food.
-contains alcohol (also have nonalcohol versions).
-more frequent professiona

What are the longest-used mouth rinse agents?

phenolic compounds (or essential oils) -- best known product is Listerine.
*not shown to be an effective anti-caries rinse, but clinical studies have been shown reduction of plaque scores by about 25% and ginigivitis by 30% by use of these compounds.
nega

There is no need to consider total fluoride exposure that the child recieves from other sources, such as school rinse programs, toothpaste or prepared foods with fluoride, when the dentist prescribes fluoride supplements. (T/F)

False

Fluoride supplements are not desired when the community water supply has a fluoride content of higher than 0.6ppm. (T/F)

True

Types of Fluoride and uses:

-Acidulated phosphate fluoride (APF)--most often used in children.
-Soduim fluoride (NaF)-- most often used on adults becuse APF tends to etch surfaces of resorations.

Fluoride varnishes are replacing the use of foams in dental offices, because varnishes do not have unpleasant side effects of nausea, vomitting, and gagging (as seen with tray application of foam). (T/F)

True
*varnish can be painted directly onto early dental caries that cna remineralize.

What is the most commonly used fluorides in the dental office?

topical gels or foams that are applied for 4 minutes in disposable trays.
*1 minute applications are not recommended by the ADA because the application only delivers approximately 85% of the fluoride that a 4 minute application delivers.

Candidates for professionally applied fluorides:

-Children with newly erupted permanent teeth.
-Children and adults at high risk for caries.

Self-applied fluoride gels are recommended for:

-individuals who are at moderate to high risk for dental caries.
-orthodontic patients--prevent caries/decalcificatio around brackets.
-elderly patients with xerostomia who are at risk for root caries.

Self-applied fluoride gels:

-available by prescription as 1.1% neutral NaF (5000ppm) or 0.4% stannous fluoride (900ppm fluoride).
stannous fluoride may cause some staining on surface of teeth.
-can be brushed on teeth or applied in custom trays.

Children younger than what age should not use fluoride gels because of the risk of swallowing?

6 years of age
*these children should also be supervised when brushing and given only a pea-size of regular toothpaste once a day.

When used as a daily rince program, OTC fluoride rinses provide a reduction in caries by what percent?

28%
*available in 0.05% NaF (225ppm), rinse for 30-60 seconds, NPO for 30 minutes, use before bedtime.
*prescription rinses contain 0.2% NaF or 0.63 stannous fluoride.

Studies conducted after the 1950's have shown that sodium monofluorophosphate (MFP) and NaF to be more effective and and chemically stable than stannous fluoride. (T/F)

True

What is the fluroide content of most toothpastes?

about 1000ppm

Prophy paste remove a small amount of fluoride-rich enamel surface. (T/F)

True

Fact or Thought?
Some of the lost fluoride can be regained by incorporating fluoride in the paste.

A THOUGHT...no proven as a fact!
*1.23% APF is the most common fluoride additive.

What is the lethal dose of fluoride for a chold weighing 20 pounds?

Approximately 700 to 1500 mg of NaF
*if this occurs-- vomiting should be encouraged, milk of magnesia/ or Cow's milk should be given.

What is the purpose a sealant?

to prevent dental caries in pits and fissures.

The greatest benefit from fluoride has been seen smooth surfaces of the enamel. (T/F)

true

Wha percentage of caries in children are found in pits and fissures?

88%

Pits and fissures collect bacteria that cannot be removed from toothbrushing, which makes it a great location for sealants. (T/F)

true

Which group can benefit the most from sealants?

low-income children.
*utilization of sealants in this group is only about 30%.

Sealants should not be used on incipient caries. (T/F)

false
*when incipient caries are sealed it cuts off the bacteria's nutrients supply which in turn stops tor inactivates tge caies process.
*ONLY INCIPIENT CARIES SHOULD BE SEALED! more severe caries need to be handled with a restorative procedure.

Treatment of carious teeth with sealants results in what percentage of a reversal from a caries-active to a caries-inactive state?

89%

Factors a dentist must consider when recommending sealants:

-age
-oral hygiene
-caries risk
-diet
fuoride history
-tooth type and morphology

Sealants therapy is aimed at permanent teeth, but primary teeth msy b sealed to reduce the caries rate and prevent premature tooth loss. (T/F)

true

At what rate does molars decay more frequently than premolars?

3 to 4 times more frequently

Maxillary central and lateral incidors have lingual pits that sometimes require sealing. (t/f)

True
*emphasis is placed on sealing first andsrvond molars.

Polymerization of a resin (such as sealants) occur by one of what two methods?

-self-cure (chemical reaction)
-light-cure (light activation)
*self curing involved two components, the initiator and the acellerator.
*light curing sealants are one-component systems that ise blue lights to polymerize them.

Sealants are heavily filled with fillers? (T/F)

False
*Sealant material is not as filled as most composits, becuase they would be too viscous to flow into narrow pit fissure.

All sealants appear radiolucent in radiographs. (T/F)

False
*MANY sealants do appear radiolucent, but some included fillers that cause it to show up radioopaque.

On average, how long does it take self-curing sealant material to final-set?

about 2 minutes from the start of mixing the two components.

What is an advantage of self-curing over light-curing?

One mix of sealnt material can be applied to more than one quadrant at a time (faster application).

How much time does the light-curing sealant require for polymerization (curing)?

about 20 seconds--with a standard halogen light. LED and laser curing lights take less time.

What is an advantage of light-curing sealant material over self-curing?

Light-curing does not require mixing, therefore no bubbles are in the material.

Sealants are only availabnle in one color. (T/F)

False, they are available in a variety of colors (clear,amber, tooth color, or opaque white), but patients usually prefer clear and tooth-colored sealants.
*However it is easier for the dental team to identify the presence of sealants at the time of place

Does the presence or absence of organic fillers in sealant material make then wear faster?

The absence of organic filler cause the sealants to wear faster, because they are less viscous.
*occlusion can also cause sealants to wear.

Why do some dentist choose to use flowable composite as sealants?

Because they ar more heavily filled and therefore are more resistant to wear while at the same time have adequate flow to enter the fissures.

What can cause sealants from flowing into the bottom of fissures?

-debris
-water contamination
-material that is too viscous. (too many fillers)

How does the ADA Concil on Scientific Affairs feel about the routine opening of fissures with cutting instruments prior to sealant placement?

It does no recomment this!

Steps to placement of a sealant:

1) Clean surface with pumice, rinse, and dry. --cleans debris.
2) Place etch --for retention, roughens enamel and opens pores.
3) rinse, dry, isolate.
4) apply sealant.
5) cure.

What are bonding resins?

-Low viscous resins that can flow into fissures into microscopic porosities created created by acid etching. The resin containing sealant is the bonded to it. (resin-resin bond).
-A relatively new finding that is not used by many clinicians.

What is the oxygen or air- inhibited layer of a sealant?

A very thin layer of uncured resin on the surface of cured sealant. It appears shiny and is wet to the touch. This is because the set of the resin was inhibited by contact with the oxygen in the air.

Sealant and bonding agents should be promptly recapped to prevent loss of volatile monomers that would create a very viscous liquid that cannot penetrate fissure and etch enamel. (T/F)

True

Failure of a sealant may be seen...

-Immediately (loss of sealant)
-At subsequent visits (complete or partial loss)
-Retained sealants that are leaking and could result in dental caries beneath the sealant.

Which teeth most frequently lose sealants?

Maxillary and mandibular second molars, because it difficult to maintain isolation.

Etched enamel begins reminieralization how long after being etched?

After about 24 hours

Sealants that are too high can...

-interfer with pt's bite.
-cause soreness of jaws and teeth.

Most sealant failures occur within what time period?

3 to 6 months.

How does the ADA Council on Scientific Affairs feel about glass ionomers being used as sealants?

The do not recomment it. They only recommend resin based sealants.

Why are glass ionomers sometimes udes as sealants?

Becuase of their adhesion to the enamel and their release of fluoride into the surronding tooth structure. However their retention rates are low.