Understanding Your Filling Options

Key Takeaway: When your dentist finds a cavity, you have choices about what material to use for the filling. Each option has pros and cons related to longevity, cost, appearance, and ease of placement. There's no perfect filling for every situation. The best...

When your dentist finds a cavity, you have choices about what material to use for the filling. Each option has pros and cons related to longevity, cost, appearance, and ease of placement. There's no perfect filling for every situation. The best choice depends on your specific tooth, cavity location, and what matters most to you.

Your dentist considers several factors when recommending a material: cavity size, tooth location (front teeth need to look good; back teeth need to be strong), whether the material will show, how long the filling should last, and your budget. Learn more about Benefits of Crown Vs for additional guidance. This guide explains the main options so you understand the tradeoffs.

Direct Composite Resin

Composite resins are plastic materials with filler particles. The plastic provides flexibility. The fillers provide strength. Different fillers create different effects. Larger fillers are stronger but harder to polish. Smaller fillers polish better but are slightly weaker.

Composition and Properties

Resin Base: The plastic forms the base. Different types of plastic are used. Some are stronger. Some shrink less. Fillers: Fillers are mixed into the plastic. Larger fillers make stronger restorations but are harder to polish smooth. Smaller fillers polish better. Shrinkage: Composite shrinks 3-6% when the light hardens it. Dentists place it in layers to reduce stress from this shrinkage.

Clinical Properties

Good Points:
  • Looks natural
  • Done in one visit (no lab)
  • Less tooth removal needed
  • Can be repaired
  • Bonds well
  • Patients like it
Bad Points:
  • Technique matters—must keep it dry
  • Can shrink and leak
  • Wears out over time
  • Stains (especially in smokers)
  • Doesn't last as long as silver filling
  • Costs more than silver

Clinical Longevity

Contemporary systematic reviews demonstrate composite restoration survival rates of:

  • 5-year survival: 88-95%
  • 10-year survival: 70-85%
  • 15-year survival: 50-70%

Back tooth composites show slightly lower longevity than front tooth composites. Restoration longevity depends significantly on:
  • Cavity size (larger restorations fail more frequently)
  • Bond quality (single-step systems show lower longevity than total-etch systems)
  • Placement technique (layered placement shows superior longevity)
  • Patient habits (smokers and staining beverage consumers show faster degradation)

Indication and Contraindication

Indications:
  • Anterior caries restorations
  • Small to medium posterior caries
  • Esthetic demands requiring tooth-colored restoration
  • Conservative preparation preferred
  • Patients with documented resin allergy (when composite is free of problematic components)
Contraindications:
  • Large posterior caries where composite bulk exceeds optimal thickness
  • Severe attrition cases where minimal tooth structure remains
  • Cases where long-term longevity is paramount (patient age, restoration risk)
  • High-stress situations (significant posterior functional cusp coverage)

Dental Amalgam

Amalgam consists of mercury liquid combined with a powder alloy mixture (typically silver-tin-copper). This creates a plastic mass that hardens into a metallic restoration. Despite decades of controversy about mercury, controlled studies show no adverse health effects from properly placed and maintained amalgam restorations.

Composition and Properties

Alloy Composition The powder comprises silver (40-70%), tin (12-32%), copper (4-30%), and smaller amounts of zinc and indium. These elements provide the mechanical properties. Mercury is merely the matrix carrier. Setting Mechanism Mixing mercury with the alloy powder initiates phase changes. Initially plastic, the mixture gradually sets over 6-24 hours. Setting is not instantaneous. Final hardness develops over days. Strength Amalgam develops substantially greater compressive and tensile strength compared to composite resin. Amalgam exhibits minimal creep (permanent deformation under load). Wear resistance is superior to composite.

Clinical Properties

Advantages:
  • Superior longevity—10-30+ year clinical lifespan is routine
  • Excellent wear resistance
  • Lower technique sensitivity—moisture contamination does not prevent adequate set
  • Lower cost than composite or ceramic
  • Ease of manipulation and placement
Disadvantages:
  • Metallic appearance unacceptable for esthetic demands
  • Nonbonded restorations require aggressive preparation and retention form
  • Tooth discoloration from metallic ions (silvering effect on enamel)
  • Expansion upon setting can create marginal discrepancies
  • Removal is destructive—requires additional tooth removal to gain access
  • Maintenance involves managing corrosion over years
  • Recurrent decay beneath margins is common after 10+ years

Clinical Longevity

Amalgam restorations demonstrate:

  • 10-year survival: 85-90%
  • 20-year survival: 60-75%
  • 30-year survival: 40-50%

The most common reasons for replacement are secondary decay (40%), fracture of restoration margin (30%), and secondary fracture of tooth structure (20%).

Indications and Contraindications

Indications:
  • Large posterior restorations requiring maximum longevity
  • Situations where moisture control is difficult
  • When cost is the primary concern
  • High-risk caries patients where rapid replacement expense is prohibitive
Contraindications:
  • Anterior visible teeth
  • Esthetic-conscious patients
  • Patients with documented mercury sensitivity (extremely rare)
  • Small restorations where composite performs adequately

Glass Ionomer Cement

Glass ionomer consists of fluoride glass powder mixed with acid liquid. This produces a cement with unique properties including active fluoride release and chemical adhesion to tooth structure.

Composition and Properties

Glass ionomers release fluoride continuously. This provides cavity-preventing effects, particularly in high-risk patients. The cement chemically bonds to tooth structure. This eliminates the need for mechanical retention (undercuts).

Initial and Final Setting Glass ionomers set chemically at room temperature without light activation (though light-activated versions are available). Setting is gradual. Moisture protection is necessary immediately post-placement. Mechanical Properties Glass ionomers exhibit lower mechanical strength compared to composite or amalgam. Compressive strength ranges 150-200 MPa versus 350-550 MPa for amalgam. Brittleness makes glass ionomers susceptible to fracture in stress-bearing regions.

Clinical Properties

Advantages:
  • Fluoride release provides anticariogenic benefit
  • Chemical adhesion to tooth structure
  • Moisture tolerance compared to other materials
  • Low technique sensitivity
  • Inexpensive
  • Biocompatibility
Disadvantages:
  • Low mechanical strength limits use in stress-bearing areas
  • High solubility initially—moisture exposure during setting compromises restoration
  • Relatively short clinical longevity (3-5 years typically)
  • Surface degradation and erosion over years
  • Limited esthetic capability (opaque, monochromatic)
  • Difficult to achieve precise contours

Clinical Longevity

Glass ionomer restorations show:

  • 3-year survival: 60-80%
  • 5-year survival: 40-60%

Longevity depends significantly on moisture exposure during setting and early post-operative period. Proper moisture protection dramatically improves outcomes.

Indications and Contraindications

Indications:
  • Primary dentition restoration (temporary nature acceptable)
  • High caries risk patients benefiting from fluoride release
  • Root surface lesions and cervical caries
  • Base liner under composite restorations
  • Temporary restorations
  • Pediatric patients where cooperativity is limited
Contraindications:
  • Stress-bearing areas or large carious lesions
  • Posterior teeth requiring high strength
  • Situations where longevity exceeds 5-7 years

All-Ceramic and Porcelain Restorations

Ceramic materials (porcelain, lithium disilicate, zirconia) are fabricated indirectly in a laboratory. This follows tooth preparation and impression taking. These restorations provide superior appearance and longevity compared to direct materials.

Material Types

Feldspathic Porcelain Traditional porcelain composed of feldspar, silica, and kaolin. Processed through high-temperature firing. Excellent appearance with superior color matching. Lower strength than contemporary ceramics. Susceptible to fracture under concentrated loading. Leucite-Reinforced Ceramic (IPS Empress) Addition of leucite crystals increases strength versus feldspathic porcelain. Strength is 160-170 MPa—moderate compared to zirconia. Good appearance with improved strength. Lithium Disilicate (IPS e.max) Contemporary ceramic with lithium disilicate crystals. Strength reaches 350-400 MPa. Excellent appearance with superior strength. Currently popular for full-coverage crowns and large inlays. Zirconia (Yttrium-Tetragonal Zirconia Polycrystal) Zirconia has exceptional strength (900-1400 MPa). Highly resistant to fracture. Lower appearance—often layered with porcelain for color and appearance enhancement. Increasingly popular for back tooth crowns and bridges.

Clinical Properties

Advantages:
  • Superior appearance with natural translucency
  • Excellent color stability. No discoloration over decades.
  • Outstanding longevity. 15-20+ years routine.
  • Excellent wear characteristics. Does not cause opposing tooth abrasion.
  • Biocompatible with excellent tissue response.
  • Low plaque accumulation compared to composite.
Disadvantages:
  • Higher cost than direct materials
  • Requires tooth preparation and multiple appointments
  • Irreversible. Tooth structure cannot be recovered if restoration is damaged.
  • Potential for fracture if prepared inadequately or subjected to excessive lateral forces
  • Complex repair if marginal failure develops. Often requires replacement rather than repair.

Clinical Longevity

All-ceramic restorations demonstrate:

  • 10-year survival: 90-95%
  • 15-year survival: 85-92%
  • 20-year survival: 80-88%

Longevity depends on ceramic material, tooth preparation shape, and cement selection. Zirconia and lithium disilicate show superior longevity compared to feldspathic porcelain.

Indications and Contraindications

Indications:
  • Anterior esthetic demands requiring maximum longevity
  • Posterior teeth requiring maximum strength and esthetics
  • Multiple tooth restorations where color stability is paramount
  • Patients with demanding esthetic standards
Contraindications:
  • Single posterior tooth restorations in bruxism patients (fracture risk with zirconia)
  • Patients unable to tolerate multiple appointments
  • Situations where cost must be minimized

Gold Restorations

Gold alloys (typically 80%+ gold, 15-20% copper, small percentages of other elements) represent the highest quality restoration material available in dentistry.

Composition and Properties

Gold alloys exhibit exceptional corrosion resistance, excellent longevity, minimal wear to opposing teeth, and superior marginal adaptation when properly constructed.

Mechanical Properties: Compressive strength exceeds 350 MPa. Creep is minimal. Ductility allows adjustment without fracture. Wear of opposing teeth is minimal. These materials can be adjusted and refined without breaking.

Clinical Properties

Advantages:
  • Unparalleled longevity. 40+ year restorations are documented.
  • Minimal corrosion and excellent biocompatibility
  • Superior marginal adaptation
  • Minimal opposing tooth wear
  • Adjustable without fracture
Disadvantages:
  • High cost (gold price fluctuations make budgeting uncertain)
  • Metallic appearance unacceptable for visible teeth
  • Requires expertise. Not all laboratory technicians excel at gold fabrication.
  • Difficult to repair if marginal failure develops

Clinical Longevity

Gold restorations show:

  • 10-year survival: 95%+
  • 20-year survival: 90%+
  • 30-year survival: 85%+

Indications and Contraindications

Indications:
  • Posterior large restorations in high-stress situations
  • Patients prioritizing longevity above cost
  • Cases where esthetics permit metal visibility
Contraindications:
  • Anterior esthetic zones
  • Cost-conscious patients

Selection Criteria by Cavity Classification

Class I Cavities (Chewing Surface)

Amalgam: Excellent choice for large, deep chewing surface cavities. Superior longevity and strength. Composite: Acceptable for small-medium chewing surface cavities. Appearance advantage is minimal (chewing surfaces not visible). Consider patient preference and cost. Indirect (Inlay/Crown): Consider for very large chewing surface cavities. Superior longevity justifies cost and appointments.

Class II Cavities (Chewing Surface-Between Teeth)

Amalgam: Gold standard. Superior longevity documented. Composite: Acceptable for small-medium cavities. Moisture control and access are challenges. Indirect (Inlay): Superior for large cavities and back tooth appearance demands.

Class III and IV Cavities (Front-Between Teeth/Biting Edge)

Composite: Excellent choice. Appearance is essential. Glass Ionomer: Acceptable for root surface cavities. Indirect (veneer): Consider for large front cavities or high appearance demands. Every patient's situation is unique. Talk to your dentist about the best approach for your specific needs.

Conclusion

Optimal restoration material selection requires understanding material properties, clinical longevity evidence, and individual case parameters. Contemporary practice increasingly emphasizes evidence-based material selection informed by systematic reviews and clinical outcomes research. The ideal restoration provides optimal longevity, appearance, and functional outcomes. It respects biological principles and patient preferences.

When your dentist finds a cavity, you have choices about what material to use for the filling. Talk to your dentist about which options work best for your unique situation. Don't hesitate to ask questions during your appointment. For additional guidance, read our article on Risk And Concerns With Tooth Color Changes.

> Key Takeaway: Understanding Your Filling Options