Comparison of Direct Restorative Materials - Dental Materials Lecture Note

Direct restorative materials are what patients normally call fillings. Direct composite restorations are placed at the time that the cavity preparation is cut.  Indirect composite restorations are built in a laboratory from a model made from an impression that the dentist takes on the day of the cavity preparation.  They are then inserted on a subsequent visit.

Comparison of Direct Restorative Dental

Factors	Amalgam (silver)	Composites Direct and Indirect	Glass lonomers	Resin lonomers (compomeres)
General Description	A mixture of mercury and silver alloy powder that forms a hard solid metal filling, Self-hardening at mouth temperature,	A mixture of submicron glass filler and acrylic resin that forms a solid tooth-colored restoration. Self- or light-hardening at mouth temperature.	Self-hardening mixture of fluoride containing glass powder and organic acid that forms a solid tooth-colored restoration able to release fluoride.	Self- or light-hardening mixture of sub-micron glass filler with fluoride containing glass powder and acrylic resin that forms a solid tooth-colored restoration able to release fluoride.
Principal Uses	Dental fillings and heavily loaded back tooth restorations.	Esthetic dental fillings and veneers,	Small nonload-bearing fillings, cavity liners and cements for crowns and bridges.
Leakage and Recurrent Decay	Leakage is moderate, but recurrent decay is no more prevalent than other materials.	Leakage low when properly bonded to underlying tooth; recurrent decay depends on maintenance of the tooth-material bond.	Leakage is generally low; recurrent decay is comparable to other direct materials, fluoride release may be beneficial for patients at high risk for decay.	Leakage is low when properly bonded to the underlying tooth; recurrent decay is comparable to other direct materials, fluoride release may be beneficial for patients at high risk for decay.
Overall Durability	Good to excellent in large load-bearing restorations.	Good in small-to-moderate size restorations.	Moderate to good in nonload-bearing restorations; poor in load-bearing.
Cavity Preparation Considerations	Requires removal of tooth structure for adequate retention and thickness of the filling.	Adhesive bonding permits removing less tooth structure.
Clinical Considerations	Tolerant to a wide range of clinical placement conditions, moderately tolerant to the presence of moisture during placement.	Must be placed in a well-controlled field of operation; very little tolerance to presence of moisture during placement.
Resistance to Wear	Highly resistant to wear. Brittle, subject to chipping on filling edges, but good bulk strength in larger high-load restorations.	Moderately resistant, but less so than amalgam.	High wear when placed on chewing surfaces.
Resistance to Fracture	Brittle, subject to chipping on filling edges, but good bulk strength in larger high-load restorations.	Moderate resistance to fracture in high-load restorations.	Low resistance to fracture.	Low to moderate resistance to fracture.
Biocompatibility	Well-tolerated with rare occurrences of allergenic response
Post-Placement Sensitivity	Early sensitivity to hot and cold possible.	Occurrence of sensitivity highly dependent on ability to adequately bond the restoration to the underlying tooth.	Low	Occurrence of sensitivity highly dependent on ability to adequately bond the restoration to the underlying tooth.
Esthetics	Silver or gray metallic color does not mimic tooth color.	Mimics natural tooth color and translucency, but can be subject to staining and discoloration over time.	Mimics natural tooth color, but lacks natural translucency of enamel.
Relative Cost to Patient	Generally lower; actual cost of fillings depends on size.	Moderate; actual cost of fillings depends on size and technique.
Average Number of Visits to Complete	One	One for direct fillings; 2+ for indirect inlays, veneers and crowns.	One	One