Polishing Agents Study Guide

Polishing Agents

Definitions of Key Terms

  • Cutting: The act of removing material from a surface.

  • Abrasion: The process of wearing down surfaces through friction.

  • Finishing: A process that prepares a surface for polishing by reducing roughness.

  • Polishing: The final step that produces a shiny surface by smoothing out any surface imperfections.

Rationale for Polishing

  • Improves esthetics: Enhances the appearance of the dental surface.

  • Improves surrounding tissue health: Healthier surrounding gum tissue as smooth surfaces are less prone to irritation.

  • Increases longevity of restorative materials: Well-polished restorations last longer.

  • Removes excess and smooths roughness: Enhances comfort and aesthetics.

  • Reduces adhesion: Smooth surfaces resist the accumulation of plaque and stains, improving oral hygiene.

  • Reduces corrosion: Prevents degradation of restorative materials.

Factors Affecting Abrasion

  • Size of particles: Larger particles cause more aggressive abrasion, while smaller ones are gentler.

  • Shape of particles: Irregular particles may abrade surfaces more than uniformly shaped ones.

  • Hardness of particles: Harder particles are more effective at abrading other materials.

  • Number of particles contacting surface: Higher numbers lead to increased abrasion.

  • Pressure applied: More pressure increases the rate of abrasion.

  • Speed of application: Faster movement can enhance the abrasion effect.

  • Lubrication/Dilution: Affects the effectiveness of the abrasive and may reduce damage to surfaces.

Types of Abrasives

  • Diamonds:

    • Used in burs and polishing pastes; cuts through hard materials.

    • Example: Perio furcation files studded with fine diamonds.

  • Aluminum Oxide:

    • Coated on finishing/polishing discs.

    • Available in various grades:

    • 3/8" (2381C, 2381M, 2381F, 2381SF)

    • 1/2" (2382C, 2382M, 2382F, 2382SF)

    • Synthetic powder abrasive used in microetchers to prepare surfaces for bonding.

  • Carbide Finishing Burs:

    • Made of carbide steel and are used for cutting and finishing but are not typically used by hygienists.

  • Silicon Carbide:

    • Coats discs and rotary devices; used for finishing.

    • Very hard, comparable to diamond.

  • Sand:

    • Used in finishing processes for composites and metal restorations, available in coated discs and handheld strips.

  • Pumice:

    • Formed from volcanic silica; it is very fine and used in the dental office.

    • When used, it is mixed with water into a slurry.

    • Preferred over prophy paste before sealants as it leaves a smoother surface.

  • Silicon Dioxide:

    • Commonly found in prophy pastes such as NUPRO (with fluoride) and other brands.

  • Calcium Carbonate:

    • A mild abrasive found in prophy pastes, often referred to as