Dental Materials Final

What is the primary goal of finishing and polishing restorations?

To remove excess material, smooth surfaces, and produce an aesthetically pleasing appearance with minimal trauma to hard/soft tissue.

What are the advantages of a smooth surface in dental restorations?

It resists accumulation of soft deposits and stains, is less irritating to tissues, is esthetically pleasing, more resistant to the effects of corrosion and surface breakdown, and can help motivate pt to maintain it through self care.

What is the purpose of finishing in dental restorations?

To remove excess material to develop the surface morphology and functional form.

What is the difference between gross finishing and fine finishing?

Gross finishing first removes large excesses of material using coarse or medium grit, while fine finishing refines the anatomic physiology using medium and fine instruments.

What is the purpose of polishing in dental restorations?

To remove scratches from the surface of a restoration with a series of abrasive particles moving in a sequence from coarse to fine and producing a smooth glossy surface.

What is selective polishing?

A technique where clinicians choose appropriate materials to polish surfaces without causing excessive damage. Determining the amount and rate of abrasion is an important.

What is full-mouth polishing?

The entire mouth is polished, typically using a rubber cup and prophy paste or air polisher.

What is the current standard of care for polishing practices?

Selective polishing.

What are the benefits of polishing and finishing dental restorations?

Decreased biofilm retention, resistance to corrosion/tarnish, increased longevity, decreased attrition during chewing, improved aesthetics, and improved health of surrounding tissues.

What is air polishing?

A procedure that uses air, water, and an abrasive powder to polish supra and subgingivally.

What pressures are typically used in air polishing?

Approximately 40-60 psi.

What are the only powders that should be used subgingivally during air polishing?

Glycine and erythritol. Can also be safely used on titanium implants and orthodontically banded/bracketed teeth.

What is the difference between supragingival and subgingival air polishing?

Supragingival polishing removes stains and deposits from enamel, while subgingival polishing detoxifies root surfaces in shallow or moderate periodontal pockets.

What is air abrasion or microabrasion?

Uses greater compressed air pressure and 27- or 50-μm aluminum oxide powder particle size for chairside cleaning of cast appliances.

What are the risks of over-polishing?

Excessive enamel removal, hot/cold sensitivity, increased biofilm accumulation due to surface roughness, deep scratches, and damage to restorations.

What are some types of polishing agents used in dentistry?

Aluminum oxide, tin oxide, pumice, and sodium bicarbonate.

What is the aluminum oxide used for?

Used to smooth enamel, finish metal alloys and ceramics, polish highly filled/hybrid composites and porcelain.

What is the tin oxide used for?

Used as final polishing agent for enamel restorations. Nonabrading cleaning paste for implants.

What is pumice used for?

Used to polish tooth structures and restorations. Fine, medium and coarse laboratory pumice not used in the mouth.

What is sodium bicarbonate used for?

For supragingival air-polisher and dentifrice. Used as a cleaning agent and can remove stains and soft deposits from enamel surfaces.

What factors affect the abrasiveness of polishing particles?

Size, irregularity, hardness, number of particles, and the pressure and speed at which they are applied.

What are the consequences of improper polishing techniques?

Excessive enamel removal, hot/cold sensitivity, roughening and over reduction of surfaces, and damage to restorations.

What is the recommended distance for the air polishing nozzle from the tooth surface?

3 to 4 mm.

What angle should the air polishing nozzle be held at on smooth surfaces?

60 to 80 degrees.

What angle should the air polishing nozzle be held at on occlusal surfaces?

90 degrees.

What is the role of glycine in air polishing?

It is effective for biofilm removal but does not remove stains.

What is the purpose of air abrasion in dentistry?

To clean cast appliances, repair restorations, and prepare tooth surfaces before bonding.

What should be avoided when using air polishing on restorations?

Using powders that are too abrasive, which can damage the tooth structure.

What is the effect of increased pressure and speed during polishing?

It increases the rate of abrasion and can lead to deeper scratches and potential damage.

What are the indications for using air polishing?

Patients with supragingival extrinsic stains, biofilm accumulation, and biofilm-induced inflammation.

What is the advantage of using calcium sodium phosphosilicate powder?

It has desensitizing results and is less abrasive than traditional prophy paste.

What are the advantages of air polishing in stain and debris removal?

Fast and effective at removing stains and debris from pits and fissures. Less abrasive than traditional polishing.

What is the role of air polishing in sealant preparation?

Increased debris in fissures prevents adequate etching and penetration of sealant, this prevents sealant failures by cleaning and preparing surfaces before materials are placed.

What does air polishing not replace?

It does not replace ultrasonic or hand scaling for removal of calculus.

What is the difference between prophy paste and toothpaste?

Prophy paste is used in the dental office for polishing.

Toothpaste is an OTC product for home use to enhance resistance to discoloration and plaque accumulation.

What is the relative abrasiveness of prophy paste?

Mixture of 50-60% abrasives like pumice, tin oxide, and lubricants. 20x more abrasive to dentin and 10x more abrasive to enamel than toothpaste.

What is the relative abrasiveness of toothpaste?

20-40% abrasives, coloring, flavoring, and therapeutic agents.

What does the ADA Seal of Approval ensure?

It indicates that abrasive particles in the dentifrice do not exceed max acceptable abrasiveness and that scientific data verify claims made by the manufacturer.

What does the ADA Seal of Approval not gurantee?

Does not guarantee that the product will be most effective for specific individuals, nor does it guarantee against side effects.

What is the purpose of dental sealants?

To seal noncarious pits and fissures to reduce or eliminate dental caries.

What factors indicate the placement of sealants?

Age, oral hygiene, caries risk, diet, fluoride history, tooth type, and tooth morphology.

What are characteristics of deep pits?

Vulnerable due to shape, deep narrow channels, collect bacteria and debris that can't be removed through brushing teeth. Uncoalesced, steep grooves and can be sticky.

What are characteristics of shallow pits?

Easy to access/clean, do not accumulate bacteria/debris, and have coalesced grooves (fused together).

What is the step-by-step process for sealant application?

1. Place dam or cotton rolls to isolate, 2. Clean surface with pumice, 3. Rinse and dry, 4. Etch enamel for 20-30 sec, 5. Rinse surface, 6. Replace cotton rolls, 7. Dry surface, 8. Apply sealant material, 9. Cure, 10. Check with explorer, 11. Remove cotton rolls/dam, 12. Check occlusion and contacts.

What is the purpose of acid etching on enamel?

To roughen the enamel surface to allow sealant material to penetrate open pores for better retention.

How do you evaluate sealant after placement?

Explorer is used to check the sealant and ensure that all pits are covered, the sealant is well retained and there are no holes in the sealant. If it is too thick, it might cause interreference with the patient's bite.

What are causes of sealant failure?

Due to saliva contamination, an air water syringe that leaks water, moisture from breath during application, or excessive material causing blockage.

What are the types of sealant materials?

Chemically similar to composite resins, often based on dimethacrylate monomer that is Bis-GMA or UDMA resins.

What are the different types of sealant failure and their clinical significance?

Partial or complete loss due to moisture contamination, sealant blocking contact due to excessive material, holes in surface due to air bubbles, and sealant too high due to excessive material.

What causes tooth sensitivity?

Roots abraded by improper brushing leading to exposed dentin, erosion, abfraction (through grinding of the teeth), and Scaling/root planing procedures, and extremes of hot and cold temps.

What are conditions when desensitizers are effective?

For exposed dentinal tubules, erosion from acid, root and cervical abrasion, and after scaling and root planning.

What are conditions when desensitizers are ineffective?

Dental caries, a fracture or crack in the tooth, a high or a leaking restoration.

What theory explains tooth sensitivity related to exposed dentinal tubules?

The hydrodynamic theory, which involves nerve endings in the tubules.

What causes sharp pain in teeth?

Movement of fluid within the tubules deforms sensitive nerve endings, causing them to fire.

What are common desensitizing agents?

Toothpastes, fluoride gels/varnishes, inorganic salt solutions, resin primers/bonding agents, mineralizing agents, glass ionomer sealer, or amorphous calcium phosphate pastes.

How do desensitizing agents work?

They occlude open tubule to reduce fluid movement and stop pressure on the nerve endings or they desensitize nerve endings.

What is the purpose of topical fluoride?

To protect against erosion, inhibit bacteria, prevent caries, and promote remineralization.

How does fluoride help prevent caries?

It makes it harder for acids from bacteria to demineralize tooth structure.

What is the role of fluoride in saliva?

Fluoride is incorporated into enamel crystals during remineralization, forming fluorapatite.

What is SDF used for?

Used to treat dentinal hypersensitivity and can kill bacteria to prevent biofilm from forming on the tooth.

What is the recommended application frequency for fluoride varnish and why?

Twice a year for direct application to early dental caries with the potential to remineralize.

What are the methods of application for gels and foams?

Applied for 4 minutes in disposable trays used fluorides in the dental office; however, varnishes have now taken their place.

What are the methods of application for self applied topical gels and pastes?

They can be brushed on the teeth or applied in custom fluoride trays. For high caries risk, ortho pts, ad elderly pts with xerostomia.

What are the methods of application for OTC fluoride rinses?

0.05% NaFl 225ppm and patients are instructed to rinse with 10mL for 30-60 seconds, spit it the excess, note rinse, eat, or drink anything for at least 30minutes, and rinse with it just before bedtime.

What is the effectiveness in caries reduction of varnish and gel/foam?

Varnish: 18-77%

Gel/Foam: 85%

What is the effectiveness in caries reduction of self applied gel/paste and OTC rinses?

Self applied gel/paste: 24%

OTC rinses: 28%

What is the recommended application time for topical fluorides?

Gel/Foam: 2x Year

Self applied gel/paste: daily-weekly

OTC rinses: Daily

What is the mechanism of tooth whitening?

Peroxide or other whitening materials penetrate enamel and dentin, releasing oxygen free radicals to oxidize stains and lighten dentin color.

What are extrinsic stains?

Stains on the tooth surface caused by substances like coffee, tea, and red wine.

What are intrinsic stains?

Stains incorporated into the tooth, often due to developmental issues or trauma.

Which type of stains respond best to whitening?

Extrinsic stains, particularly yellow and light brown stains caused by aging or foods can usually be whitened more easily in about 2 to 4 weeks.

What is in-office whitening?

Ideal for patients who want results quickly. Use stronger whitening agents that are activated by light and work quicker to whiten teeth. 35-45%, 45-60 min.

What is at home whitening?

Popular and cost-effective method of whitening but the treatment interval is much longer compared with in office treatment. 10-45% Carbamide or 6-15% peroxide, 15 min-2+ hours.

What should patients do with OTC fluoride rinses?

Rinse with 10mL for 30-60 seconds, then avoid eating or drinking for at least 30 minutes.

What are the side effects of fluoride varnish compared to gel and foam applications?

Varnishes do not cause nausea, vomiting, or gagging like gels and foams.

What is the application method for dentist-prescribed home whitening?

Custom trays with whitening gel, worn for 15 minutes to overnight.

What is the effectiveness of SDF in arresting caries?

Can arrest caries at 90% when applied twice a year.

How often should patients return to the dentist during whitening treatment?

Every 2 to 3 weeks to ensure the custom whitening trays still fits appropriately, no gingival burning has occurred and take a new shade to verify progress.

What is the procedure for dentist-prescribed home whitening?

Fabricated by the dentist, and patients are given whitening gel. Instructed to wear for as short as 15min or as long as overnight.

What are common side effects of whitening treatments?

Sensitivity and irritation of gingiva, mucosa, throat, hypersensitive teeth, and sore muscles and jaw joints if trays are worn overnight.

Why is it important to address restorations before whitening?

Color of restorations will not lighten with whitening procedures and they may appear darker after procedure.

What is the timing for shade selection after whitening?

2 weeks before matching the shade of the patients whitened teeth.

What materials are commonly used in whitening products?

Hydrogen peroxide for in-office and carbamide peroxide for at-home whitening

What is microabrasion?

Non-invasive procedure that removes stains such as fluorosis by removing microscopic layers of enamel.

How is microabrasion performed?

Determine that the lesion is shallow enough to leave an adequate thickness of enamel after discoloration removal.

Clean with pumice.

Apply an acid slurry for 1 minute.

Rinse it off the tooth and repeat the process if the spot is not gone (no more than 3x).

What are the uses of Chlorhexidine?

Used one week per month to reduce levels of S. Mutans and lactobacilli until DDS determines it is not needed.

What are the side effects of chlorhexidine?

Brown stain of hard and soft tissue, taste alteration, harsh on sensitive individuals if alcohol version is used.

What is the purpose of sports guards?

To protect teeth and supporting structures from fractures and injuries during sports. Can prevent lip lacerations for athletes with ortho and protect dental work.

What are stock guards?

Over-the-counter mouthguards that are inexpensive but provide the least protection and comfort and arent adapted to the patients bite.

What are boil-and-bite mouthguards?

They are OTC horsehoe shaped mouthguards costing less than $50 and softened in boiling water and molded to the teeth for a better fit. Often difficult for inexperienced individuals to adapt and can provide false protection.

What are custom-fit mouthguards?

Professionally made guards that provide excellent fit and comfort, but are more expensive due to added steps, materials, and time involved in lab fabrication.

What is the thickness requirement for heavy contact sports mouthguards?

5mm

What is the thickness requirement for less physical contact sports mouthguards?

2mm

What are the advantages and disadvantages of soft guards?

More comfort, but suitable for patients who do not grind their teeth heavily.

What are the advantages and disadvantages of hard acrylic guards?

For patients who grind their teeth heavily, as they are more durable. Typically requires more chair-time for adjustment as it shrinks when it is cured.

What is essential for the care of mouthguards?

Daily cleaning, rinsing thoroughly with water and brushed with a toothbrush or denture brush and liquid soap when removed, and storing in an open rigid container to air dry.

What are the risk factors for obstructive sleep apnea (OSA)?

Large neck, obesity, chronic congestion, high blood pressure, diabetes, smoking, alcohol use, narrow airway.

What are treatment options for OSA?

Weight loss, exercise, reduce alcohol intake, smoking cessation, sleeping on side, nasal decongestants, CPAP machine, oral appliance, and soft palate/uvula reduction surgery.

What is the function of oral appliances in OSA treatment?

Lift the soft palate, hold tongue in a forward position, and reposition mandible forward to bring tongue away from airway.

What is the purpose of space maintainers?

Prevent adjacent teeth from drifting into open space when teeth are lost too soon.