Comprehensive Guide to Dental Biofilms, Calculus, and Stains for Dental Students

Biofilm

An organized community of microorganisms attached to a surface and held together by an extracellular matrix; dental plaque is a biofilm.

Plaque biofilm vs food residue

Plaque is a microbial biofilm and is not simply food residue.

Initial attachment

First stage of biofilm formation; the surface becomes coated and free-floating microbes attach.

Irreversible attachment

Second stage of biofilm formation; bacteria become attached to the pellicle.

Maturation I

Third stage of biofilm formation; initial colonization occurs.

Maturation II

Fourth stage of biofilm formation; extracellular slime layer and microcolony formation occur.

Dispersion

Fifth stage of biofilm formation; mature subgingival biofilms disperse.

Supragingival biofilm

Biofilm located above the gingival margin.

Subgingival biofilm

Biofilm located in the gingival sulcus; it is less cleansable, stagnant, dark, and has low oxygen.

Supragingival vs subgingival

Supragingival is above the gumline; subgingival is below the gumline/in the gingival sulcus.

Tooth-associated biofilm

Subgingival plaque associated with the tooth.

Tissue-associated biofilm

subgingival plaque associated with tissue.

Unattached biofilm

One type of subgingival plaque that is not attached to the tooth or tissue.

Saliva and biofilm

More saliva decreases plaque formation

Saliva functions

Helps remineralize teeth, washes substances away, buffers acids, and protects teeth.

Diet and biofilm

Sucrose is especially important for plaque formation; soft foods can encourage plaque retention.

Fibrous foods and plaque

Fibrous foods increase salivary flow, which increases oral clearance and buffering.

Physical removal of biofilm

An important strategy for controlling supragingival biofilm.

Biofilm composition

Mostly water and extracellular matrix, with organic and inorganic solids.

Extracellular matrix

Holds bacteria together within the biofilm.

Materia alba

A loosely attached material containing living/dead bacteria, sloughed epithelial cells, salivary proteins, and food debris.

Materia alba vs biofilm

Materia alba has no strong matrix and is easily removed by rinsing or air syringe; biofilm is more strongly attached.

Calculus

Mineralized biofilm crystals formed when calcium and phosphate salts are deposited into biofilm.

Calculus mineral sources

Saliva provides minerals for supragingival calculus; sulcular fluid and inflammatory exudate provide minerals for subgingival calculus.

Calculus and bacteria

Calculus can be covered by a layer of non-mineralized biofilm containing viable, active bacteria.

Mature calculus composition

Mostly inorganic material, including calcium, phosphorus, hydroxyapatite, and smaller amounts of other minerals; also contains organic material and water.

Three steps of calculus formation

Biofilm forms, mineralization begins, and calculus matures.

Acquired pellicle and calculus

Calculus can attach to the acquired pellicle, making it more easily removed than calculus attached to tooth irregularities.

Tooth irregularities and calculus

Calculus attached to tooth irregularities is difficult to completely remove.

Calculus layers

Calculus forms in layers parallel to the tooth surface.

Incremental lines

Lines between layers of calculus associated with pellicle deposited over previously formed calculus.

Ring calculus

A layer of calculus that encircles buccal and lingual surfaces.

Spicule calculus

Small, needle-like or pointed pieces of calculus found around line angles and appearing mesial or distal.

Ledge calculus

Subgingival shelf-like calculus that accumulates parallel to the CEJ.

Veneer calculus

A sheet or coating of calculus.

Intrinsic stain

Discoloration from within the tooth that generally cannot be altered by the RDH.

Endogenous stain

Intrinsic stain that occurs during tooth development; example is fluorosis.

Exogenous stain

Stain from an outside source that alters the internal shade of the tooth; examples include tetracycline and trauma.

Extrinsic stain

Discoloration located on the outside of the tooth from external factors.

Intrinsic vs extrinsic stain

Intrinsic stain is within the tooth; extrinsic stain is on the outside surface.

Common extrinsic stains

Tea, coffee, tobacco, red wine, colas, fruit juices, berries, and tomato sauce.

Dentifrice

Toothpaste; a paste or powder used for cleaning teeth.

Therapeutic dentifrice

A dentifrice that provides a therapeutic effect such as reducing caries, biofilm, gingivitis, or sensitivity.

Cosmetic dentifrice

A dentifrice intended to cleanse, beautify, promote attractiveness, or alter appearance.

Prophy paste

Paste used for cleansing and polishing during prophylaxis.

Prophy paste cleansing

Removes exogenous stain, pellicle, materia alba, and other debris.

Prophy paste polishing

Smooths surfaces of restorative materials without being too abrasive.

Main component of prophy paste

Abrasives.

Examples of prophy paste abrasives

Pumice, kaolinite, silicon dioxide, calcium magnesium silicate, and zirconium silicate.

GRASE

Generally Recognized As Safe and Effective.

FDA cosmetic definition

A product intended to cleanse, beautify, promote attractiveness, or alter appearance.

FDA therapeutic definition

A product intended for diagnosis, cure, mitigation, treatment, or prevention of disease or to affect body structure or function.

FDA therapeutic dentifrice categories

Anti-caries, anti-plaque/anti-gingivitis, and tooth desensitizer.

ADA Seal of Acceptance

product does what it says it does

Dentifrice monograph

FDA document establishing therapeutic dentifrice requirements such as intended use, dosage/concentration, forms, combinations, and labeling.

Active ingredient

An ingredient responsible for the therapeutic action of a product.

Inactive ingredient

An ingredient that provides stability, texture, flavor, or esthetic/cosmetic benefits rather than the therapeutic action.

Anti-caries active ingredients

Sodium fluoride, sodium monofluorophosphate, and stannous fluoride.

Anti-plaque/anti-gingivitis active ingredient

Stannous fluoride.

Dentinal hypersensitivity active ingredients

Stannous fluoride and potassium nitrate.

Stannous fluoride and sensitivity

Helps block or occlude dentinal tubules.

Potassium nitrate and sensitivity

Desensitizes the nerve from sending pain signals.

Stannous fluoride and gingivitis

Has antimicrobial effects and reduces clinical signs of gingivitis caused by biofilm.

Sodium fluoride mechanism

Forms fluoride salts on tooth surfaces that bind to calcium in hydroxyapatite and help resist acid and erosive challenges.

Stannous fluoride mechanism

Forms a stable, acid-resistant layer and has antimicrobial effects.

Caries disease process

Sugars + cariogenic bacteria + susceptible tooth → bacterial acids → low pH → demineralization → continued demineralization/remineralization → possible cavitation.

Primary cariogenic bacterium

Streptococcus mutans.

Other cariogenic bacteria

Lactobacillus and Actinomyces naeslundii.

Fluoride purpose

Fluoride inhibits demineralization, enhances remineralization, and inhibits biofilm bacteria.

Fluoride and caries

Fluoride is the gold standard for caries prevention and is especially used for smooth-surface caries.

Sealant

A resin material placed into pits and fissures of teeth at risk for caries.

How sealants prevent caries

They create a physical barrier between cariogenic bacteria and susceptible pit and fissure surfaces.

Sealant contraindications

Allergy to sealant material, caries extending into dentin, partial eruption, shallow/fused fissures, and proximal caries.

Silver diamine fluoride (SDF)

Silver provides antimicrobial action while fluoride promotes remineralization; it stains tooth structure black.

Xylitol

A sugar alcohol that cariogenic bacteria cannot efficiently metabolize and that can decrease Streptococcus mutans.

Chlorhexidine and caries

Chlorhexidine is no longer recommended for caries prevention because of lack of evidence; it can stain teeth/tongue and cause metallic taste.

High-potency fluoride

Professional fluoride products used at lower frequency.

Low-potency fluoride

Self-applied fluoride products used at higher frequency.

Topical fluoride

Fluoride that strengthens teeth already in the mouth

Systemic fluoride

Fluoride ingested into the body and incorporated during tooth formation; it can also become topical through saliva.

Sodium fluoride vs stannous fluoride

Sodium fluoride is commonly used for caries prevention; stannous fluoride also provides antimicrobial, gingivitis, and sensitivity benefits.

APF

Acidulated phosphate fluoride; an acidic fluoride product used professionally and can etch or damage some porcelain, glass, sealant, and composite restorations.

Neutral sodium fluoride

forms fluoride salts on tooth surfaces and is commonly used in toothpaste and mouthrinses.

SDF mechanism

Silver limits reinvasion of cariogenic bacteria while fluoride promotes remineralization.

Xylitol mechanism

Cariogenic bacteria cannot efficiently metabolize xylitol, reducing Streptococcus mutans levels in biofilm and saliva.

Teach-back method

A patient-centered communication technique used to check understanding and improve health literacy and outcomes.