Preventive Dental Materials Flashcards
what are preventive dental materials?
Materials designed to prevent disease or injury to the teeth and supporting tissues
They are mainly: Fluoride gels, pit and fissure sealants, and mouth protectors
what are fluoride gels, foams, rinses, and varnishes?
Fluoride gels are applied in a tray to the teeth after a dental prophylaxis to prevent smooth-surface caries
Effective in reducing the incidence of caries
Gels are made of acidulated phosphate fluoride, which contains sodium fluoride, hydrogen fluoride and phosphoric acid.
Neutral sodium fluoride foams, gels, and rinses
Varnishes containing sodium fluoride varnishes
what are properties of fluoride ?
Acidulated phosphate fluoride (gel, rinse, and foam) is acidic, can etch restorations, but can not stain them
Sodium fluoride (gel, rinse and foam) is neutral, and can not etch or stain restorations
Stannous fluoride (gel and rinse) is acidic, and can etch and stain restorations
what are pit and fissure sealants?
Pits and fissures are sites susceptible to dental caries due to their anatomic construction
They are enamel faults that are the result of noncoalescence of enamel during teeth formation.
The lack of enamel coalescence may extend to the dentoenamel junction.
They collect debris and microbial masses
Dental caries are initiated at these sites.
what is the composition and reaction of pit and fissure sealants?
Occlusal fissures can be cutaway and filled with amalgam
Pit and fissure polymeric sealants can be also used
Sealants are resins that polymerize with light activation
Polymeric sealants are similar to composite restorative materials, but are more fluid.
Enamel is etched to retain the polymeric sealants.
Dimethacrylate monomer (Bis-GMA) + Diluent + Activator +Light –> Sealant
what is the setting time, compressive strength, water sorption in 7 days, water solubility in 7 days, and wear of pit and fissure sealants?
Setting time = 60 sec
Compressive strength = 92 - 150 MPa
Water sorption in 7 days = 1.3 - 2.0 mg/cm2
Water solubility in 7 days = 0.2 mg / cm2
Wear = 22 - 23 x 10-4 mm3/mm
for pit and fissure sealants, what do retention and penetration hve to do with it?
Retention is the the result of mechanical bonding of the sealant and the etched enamel surface. Filling the fissure completely is difficult due to the presence of debris and entrapped air. Acid etching improves the filling by cleaning the area, improving wettability, increasing the surface area
Penetration must occur before polymerization. Rate of penetration = r (PC) / 2 L where r is the radius of the pit, L is its length, and PC is the penetration coefficient.
PC = δ (Cos θ ) / 2 η where δ is the surface tension, η is the viscosity of the sealant, and θ is the contact angle
what is the manipulation of pit and fissure sealants?
1) Cleansing and etching the occlusal surfaces with phosphoric acid (60 sec)
2) Rinsing with water to remove phosphoric acid which can interfere with the bonding of the sealant
3) Drying with an air syringe (15 sec)
4) Applying the sealant with a syringe
5) Activation of polymerization using a light-curing unit
6) Finishing
what are mouth protectors for and what are they made of and what is the fabrication?
Reduce oral injuries of athletes
Made of thermoplastic polymers sheets (1.6 to 3.0 mm thin) - most commonly ethylene vinyl acetate
Fabrication involves: taking an impression of the arch, pouring a model, forming the thermoplastic polymer over the model, and finishing the mouth protector
what is the proper hygiene for mouth protectors?
1) After each use, rinse with cold water
2) Occasionally clean with soap and cool water
3) Do not scrub with an abrasive dentifrice
4) Do not use alcohol solutions or denture cleansers
5) Store in the container provided
