Dental Materials PDF (1st Semester)

DENTAL MATERIALS PPT-BASED 1ST SEMESTER – DOCTOR OF DENTAL MEDICINE PREVENTIVE DENTAL MATERIALS Clinical studies have established the effectiveness of fluoride ion in lowering...

DENTAL MATERIALS PPT-BASED 1ST SEMESTER – DOCTOR OF DENTAL MEDICINE PREVENTIVE DENTAL MATERIALS Clinical studies have established the effectiveness of fluoride ion in lowering the incidence of dental caries. TOPIC OVERVIEW ○ May be used as gels in trays and gels with rinses and varnishes A. PREVENTIVE DENTAL MATERIALS B. FLUORIDE GELS, RINSES AND VARNISHES B1 COMPOSITION a. COMPOSITION b. PROPERTIES c. MANIPULATION Acidulated phosphate-fluoride (APF) C. PIT AND FISSURES SEALANTS gels contain 2% sodium fluoride, 0.34% a. COMPOSITION AND REACTION hydrogen fluoride, and 0.98% phosphoric (LIGHT-CURED) acid. b. COMPOSITION AND REACTION ○ Sodium fluoride and stannous (SELF-CURED) fluoride gels are also available. c. PROPERTIES d. MANIPULATION Varnishes containing 5% sodium D. MOUTH PROTECTORS fluoride also are available. a. TYPES AND COMPOSITION APF is contraindicated for patients with b. PROPERTIES tooth sensitivity;can cause erosion and c. FABRICATION OF MOUTH worsen tooth sensitivity PROTECTORS Neutral topical sodium fluoride foams, gels and rinses are available. A PREVENTIVE DENTAL MATERIALS ○ One product is thixotropic which contains sodium fluoride and thickening agents (polyacrylic Designed to prevent disease or injury to acid and a gum). the teeth and supporting tissues ○ The pH is adjusted between 6 and Fluoride gels are applied in a tray to 8. prevent smooth-surface caries. Values of pH in this range should Fluoride rinses and varnishes are minimize acid etching of restorative available. materials caused by more acidic APF Pit and fissure sealants are applied to gels. occlusal surfaces of posterior teeth to ○ Stannous fluoride products are prevent pit and fissure caries. effective in providing fluoride but Mouth protectors fit over teeth to can cause staining of tooth protect from sudden blows. surfaces and restorations. May also be used as trays or carriers for topical fluoride or bleaching applications, or as shields to prevent damage from B2 PROPERTIES bruxism Clinical effectiveness of APF gels varies, B FLUORIDE GELS, RINSES AND in part, on the method and frequency of VARNISHES application. PAGE 1 CHESKA ALAY – DDM 3B  DENTAL MATERIALS PPT-BASED 1ST SEMESTER – DOCTOR OF DENTAL MEDICINE ○ The typical 4-minute application A smooth-based appears more effective than a depression on 1-minute application. the occlusal A gel should be viscous enough to surface of a provide for ease of handling during tooth is termed loading of the tray and insertion, yet fluid a groove. enough for efficient contact of gel with enamel surfaces of teeth. Five percent sodium fluoride varnish is also effective in reducing orthodontic decalcification. Fissure in which debris has B3 MANIPULATION collected, dental caries has begin in the enamel APF gels are applied in soft, spongy trays ○ Teeth are kept as free from saliva as possible before application of Lack of enamel coalescence may extend the tray. to the DEJ or may be incomplete. A ribbon of gel is placed in the troughs; Such sites exhibit a high incidence of the trays are placed in position; and dental caries. pressure is applied to mold the tray 84% of caries in children 5 to 17 years of around the teeth so the gel penetrates age involve pits. between the teeth., bite for 4 minutes The purpose of sealant is to penetrate all ○ After application, the patient is cracks, pits, and fissures on occlusal instructed not to eat for 30 surfaces of teeth in an attempt to seal off minutes. susceptible areas. Rinses are not recommended for children younger than 6 years. PREVENTIVE RESIN RÉSTORATION Fissures may also be prepared with small C PIT AND FISSURE SEALANTS traditional carbide burs, specialized burs called fissurotomy burs, or by air Fluoride and plaque control programs abrasion and filled with flowable have not been completely effective in composite. reducing caries in pits and fissures. ○ A smooth-based depression on C1 COMPOSITION AND REACTION the occlusal surface of a tooth is (LIGHT-CURED) termed a groove. ○ The pit and fissure is an enamel Most are resins in which polymerization fault that is the result of non is activated by light (490 nm coalescence of enamel during wavelength). tooth formation. They are one-component systems that do not require mixing. PAGE 2 CHESKA ALAY – DDM 3B  DENTAL MATERIALS PPT-BASED 1ST SEMESTER – DOCTOR OF DENTAL MEDICINE The resin is a diluted dimethacrylate ○ Increasing the surface area monomer (bisphenol A-glycidyl ○ Forming spaces into which the methacrylate (Bis-GMA] or urethane sealant can penetrate to form dimethacrylate [UDMA]). tags ○ Activator is a diketone in the Retention of a sealant in a fissure is the presence of an organic result of mechanical bonding caused by Several sealants contain up to 50% by penetration of the sealant into the fissure weight of inorganic filler to improve and the etched areas of enamel to form durability and contain white pigment to tags improve contrast between sealant and Filling the fissure completely is difficult enamel. because air frequently is trapped in the The sealants polymerize in the mouth to bottom of the fissure, or the become a cross-linked polymer. accumulation of debris at the base of the fissure prevents it from being sealed C2 COMPOSITION AND REACTION completely (SELF-CURED) Sealants polymerized by an organic amine accelerator are supplied as two-component systems. ○ One component contains a monomer and benzoyl peroxide initiator. Acid etching of the enamel surface ○ A second component contains a improves the retention of the sealant by diluted monomer with 5% organic ○ cleaning the area to be sealed amine accelerator. ○ improving the wettability of the The two components are mixed together enamel, before application. ○ increasing the surface area ○ and forming spaces into which C3 PROPERTIES the sealant can penetrate to form tags Retention is due to mechanical bonding caused by penetration of sealant into fissures and etched areas of enamel. ○ Filling the fissure completely is difficult because air frequently is trapped or debris prevents is from being sealed completely. Acid-etching the enamel surface improves retention by: ○ Cleaning the area to be sealed ○ Improving the wettability of enamel PAGE 3 CHESKA ALAY – DDM 3B  DENTAL MATERIALS PPT-BASED 1ST SEMESTER – DOCTOR OF DENTAL MEDICINE Sealants should not be used: The tip of the light source is positioned ○ On the teeth of a patient who on the occlusal surface for at least 20 does not cooperate in seconds. maintaining good oral hygiene ○ On occlusal surfaces where pits and fissures do not exist ○ On teeth that have been free of Tags of sealant that caries for several years had penetrated the ○ On teeth with many proximal etched enamel lesions C4 MANIPULATION OF SEALANTS Six basic steps must be followed sequentially: Application of pit and ○ Cleansing and etching the fissure sealant with a occlusal surface small tube (cannula) ○ Washing these areas ○ Drying the areas ○ Applying sealant to the pits and fissures ○ Polymerizing the sealant ○ Finishing the sealant Application with Ball applicator Visible Light-Activated Sealants 37% Phosphoric acid is applied to the central fissure area of the occlusal surface with a small cotton pellet or fine brush. Leave for 60 seconds The surface is washed with water for at least 15 seconds. The washed surface is dried for 15 Tooth filled with seconds with an air syringe. completed sealant ○ Moisture interferes with retention treatment of the sealant. Isolation is maintained by use of cotton rolls and high-volume evacuation. Sealant is applied to the occlusal surface Finishing can be accomplished by using of the tooth. a cotton pellet to remove sealant that has ○ Excess is wasteful. failed to polymerize because of exposure Polymerization is activated with a to air. light-curing unit. PAGE 4 CHESKA ALAY – DDM 3B  DENTAL MATERIALS PPT-BASED 1ST SEMESTER – DOCTOR OF DENTAL MEDICINE ○ Sealant should offer resistance to taste or odor, durability, low penetration with the tip of an speech impairment, and comfort. explorer. Custom-made mouth protectors are Defects are corrected by repetition of the generally formed from thermoplastic procedure and reapplication of sealant to defective areas. polymers. Fluoride is applied after the sealant has ○ 14 cm square, thickness varies polymerized. from 1.6 to 3 mm. The most common material is a Amine-Accelerated Sealants poly(vinyl acetate)-polyethylene Require mixing of base and initiator polymer also called ethylene vinyl ○ Typically, mixing time is 10 to 15 acetate (EVA). seconds. ○ Other products have used Sealant is applied promptly. polyurethane, rubber latex, and a Setting will occur within several minutes vinyl plastisol. after application of the liquid sealant. D MOUTH PROTECTORS all players of contact sports use mouth protectors. ○ 62% of injuries occurred in unorganized sports. Injuries most commonly occur in basketball, baseball, and soccer. Most injuries occurred when the athlete was not wearing a mouth protector. trauma Players prefer the custom-made Pulpitis protectors: pulpal necrosis ○ Cleanliness resorption phenomena ○ lack of taste or odor replacement resorption ○ Durability internal hemorrhage ○ low speech impairment, and pulp canal obliteration comfort. inflammatory resorption POLYURETHANES POSSESS higher strength D1 TYPES AND COMPOSITION Hardness energy absorption but also have Three types: stock, mouth formed, and custom made higher values of water sorption ○ Use of any reduces oral injuries. and require higher processing ○ Players prefer custom made temperatures. because of cleanliness, lack of PAGE 5 CHESKA ALAY – DDM 3B  DENTAL MATERIALS PPT-BASED 1ST SEMESTER – DOCTOR OF DENTAL MEDICINE ○ Trays may be modified with D2 PROPERTIES utility wax. Removable orthodontic appliances In general, poly(vinyl should be removed. acetate)-polyethylene materials are The impression can be made with the easiest to fabricate. fixed orthodontic appliances ○ Gagging, presence of taste, irritation, and impairment of speech are problems not common to properly fabricated custom-made protectors. ○ Staining can be expected, regardless of the protector material. Orthodontic appliance blocked out on the Complaints may be received from model with dental stone or wax. athletes who dislike the feel of the harder materials. The impression is poured in stone. ○ The palate need not be As thickness is increased, energy absorption is increased, but thicker poured. materials are more uncomfortable to Forming the mouth protector can be wear. accomplished by a vacuum machine, Breakdown usually results from "bite pressure-lamination machine, or by through," tearing, or deterioration hand. from chewing. Permanent deformation can occur as the result of pressure or heat. D3 FABRICATION OF MOUTH PROTECTORS Four basic steps: ○ Taking an impression of the arch ○ Pouring a model ○ Forming the thermoplastic material over the model ○ Finishing the mouth protector An alginate impression is taken of the maxillary arch. PAGE 6 CHESKA ALAY – DDM 3B  DENTAL MATERIALS PPT-BASED 1ST SEMESTER – DOCTOR OF DENTAL MEDICINE The heating element is turned on, and the center of the sheet of material must sag. The model is trimmed 3 mm. short of the labial fold with a curved pair of surgical scissors. Edges are flamed with an alcohol torch and smoothed with moist fingers. ○ A Moore's Satin Buff Wheel or a laboratory lathe may also be used. a. Sheet of mouth protector Mouth protector on a model, trimmed with b. Upper clamp c. Lower clamp edges finished d. Model e. Perforated support plate If adjustment is required f. Heater ○ Contacting surfaces are heated g. Vacuum switch h. Switch gently with an alcohol torch. i. Sagging sheet ○ The appliance is dipped in warm water and placed in the A square sheet of material is clamped athlete's mouth. in the frame. ○ The athlete is asked to close The frame is raised to the top position until all teeth contact the just below the heating element. mouth protector. The model is centered on the ○ The mouth protector is vacuum former platform. removed to cool and then is reinserted to examine the occlusion. PAGE 7 CHESKA ALAY – DDM 3B  DENTAL MATERIALS PPT-BASED 1ST SEMESTER – DOCTOR OF DENTAL MEDICINE All teeth must contact the appliance. ○ If desired, a strip of thermoplastic material may be heated and adapted before a second layer is processed over the entire model. ○ The increased occlusal thickness allows the vertical dimension and the occlusion to be adjusted. A strap can be added. ○ A wide strap can be heat-sealed into a slit made in the mouth protector at the incisal edge of the maxillary central incisors. Two mistakes ○ Use of a sooty flame during smoothing ○ Reproduction of flaws in the model that do not exist in the arch PAGE 8 CHESKA ALAY – DDM 3B