WILK ch17 Dental Deposits & Stain

What is the acquired pellicle?

A thin, acellular, tenacious film of proteins, carbohydrates, and lipids (mainly glycoproteins) that forms over exposed enamel, dentin, mucosa, and restorative materials.

How long does it take for the pellicle to form fully after a tooth is cleaned or erupts?

Within 30 to 90 minutes.

What are the sources of the protein components of the pellicle?

Saliva, oral mucosal cells, gingival crevicular fluid (GCF), and microorganisms.

List three functions of the acquired pellicle.

Regulating mineral homeostasis (protecting against acid demineralization and scaffolding remineralization), host defense and microbial colonization, and lubrication.

Why is the pellicle described as both protective and a risk factor for disease?

It protects and lubricates the tooth, but it also provides the glycoprotein binding sites that bacteria attach to, starting biofilm formation.

How does the pellicle look when stained with a disclosing agent?

Thin with a pale stain, in contrast to the thicker, darker stain of dental biofilm.

What factors can interfere with pellicle formation and maturation?

Abrasive toothpastes, whitening products, and acidic foods and beverages.

Define dental biofilm.

A dynamic, structured community of microorganisms encapsulated in a self-produced extracellular polymeric substance (EPS) matrix that adheres to the pellicle on oral hard and soft surfaces.

What is EPS and what does it do?

Extracellular polymeric substance, a matrix of polysaccharides, proteins, and other compounds that anchors bacteria together and to the pellicle and protects the biofilm from the host immune system and antimicrobial agents.

What is the function of the open water channels in biofilm?

They separate the microcolonies and supply nutrients deep within the biofilm community.

What is the approximate composition of dental biofilm?

About 20% organic and inorganic solids (microorganisms and EPS) and 80% water.

What are the four steps in oral biofilm formation?

Pellicle formation, initial adhesion, maturation, and detachment/dispersion.

What are planktonic bacteria?

Free-floating bacterial cells that attach to the pellicle during initial adhesion and are released during dispersion.

Why is initial adhesion of bacteria considered reversible?

The adherent cells are not yet committed, so they can be dislodged by oral self-care activities such as brushing and interdental cleaning.

What is quorum sensing?

Cell-to-cell communication in mature biofilm that controls growth of the community and signals microorganisms when to leave the biofilm and find new sites.

By approximately how many hours does biofilm maturation occur?

By about 72 hours.

What happens to the biofilm if it is left undisrupted for about 7 days?

Gram-negative anaerobic bacteria are favored, increasing the risk of caries and gingivitis and eventually other inflammatory periodontal diseases.

According to Löe's classic study, what dominates early biofilm on days 1 to 2?

Gram-positive cocci with small accumulations of leukocytes.

How long does it take for gingivitis to become clinically evident in Löe's study?

Between 10 and 21 days.

How do supragingival and subgingival biofilm differ in layers and bacterial type?

Supragingival biofilm has two layers and is predominantly gram-positive aerobic; subgingival biofilm has four layers and is predominantly gram-negative, anaerobic, and motile.

Where in the subgingival biofilm are periodontal pathogens such as Porphyromonas gingivalis typically located?

In the top layers, along with spirochetes.

What is dysbiosis?

A shift in the microbial community from a health-associated pattern to a disease-associated one.

Where is supragingival biofilm formation most heavy, and where is it least?

Heaviest on lingual, posterior, and proximal surfaces; least on anterior surfaces.

What are three ways to detect dental biofilm?

Direct vision, passing the side of an explorer or probe over the tooth, and applying a disclosing agent.

Describe the sequence of events leading to dental caries in biofilm.

Fermentable carbohydrate enters the biofilm, bacteria rapidly produce acid, the biofilm pH drops, frequent acid exposure causes demineralization, then a white spot (incipient lesion), and finally a cavitated carious lesion.

What is the critical pH for enamel demineralization and for dentin?

About 5.5 for enamel and approximately 6.7 for dentin.

Why may root surfaces demineralize at a higher pH than enamel?

Dentin and cementum have a lower mineral content.

Which bacteria are most associated with caries?

Acid-tolerant Streptococcus mutans, Streptococcus sobrinus, and lactobacilli.

What determines the extent of demineralization in the caries process?

The length of time and frequency the pH is below critical level, plus biofilm composition, the pH-lowering ability of the microorganisms, and the action of saliva.

What is materia alba?

A soft, whitish, cottage cheese-like, unorganized accumulation of living and dead bacteria, desquamated epithelial cells, leukocytes, salivary proteins, and food debris.

How does materia alba differ from dental biofilm?

Materia alba is unorganized and loosely adherent, while biofilm is a structured, tenaciously adherent community; materia alba can be removed by rinsing and basic self-care.

What is vertical food impaction and what can cause it?

Food forced into open contact areas during chewing, caused by loss of proximal contact, diastemas, poorly contoured restorations, or occlusal irregularities such as plunger cusps.

Define dental calculus.

Dental biofilm mineralized by crystals of calcium phosphate mineral salts, always covered by a layer of nonmineralized biofilm containing live bacteria.

What is the difference in location between supragingival and subgingival calculus?

Supragingival calculus is coronal to the gingival margin; subgingival calculus is apical to the margin and extends toward the base of the pocket.

What is the mineral source for supragingival versus subgingival calculus?

Saliva for supragingival calculus and gingival crevicular fluid for subgingival calculus.

What are the most frequent sites of supragingival calculus and why?

Lingual surfaces of mandibular anterior teeth and facial surfaces of maxillary first and second molars, opposite the openings of the submandibular and parotid salivary gland ducts.

Why is subgingival calculus dark brown, green, or black?

It is exposed to blood and blood breakdown products, and some bacteria produce pigment.

What are the average mineral contents of supragingival and subgingival calculus?

About 37% for supragingival calculus and about 58% for subgingival calculus.

What are the four types of calcium phosphate crystals found in calculus?

Brushite, octacalcium phosphate, hydroxyapatite, and whitlockite.

What is the predominant inorganic component in exterior layers of supragingival calculus versus subgingival calculus?

Octacalcium phosphate for supragingival calculus and whitlockite for subgingival calculus.

What is the driving force for calculus mineralization?

Supersaturation of saliva.

What is the sequence of crystal maturation in calculus formation?

Brushite, then octacalcium phosphate, then whitlockite, and finally stable hydroxyapatite (around 8 months).

About how long does it take for soft biofilm to change to mature mineralized calculus?

About 12 days on average, though mineralization can begin within the first 2 days.

Name three inhibitors of calculus formation.

Urea, zinc, and pyrophosphates.

What are the three modes of attachment of calculus to the tooth?

Attachment by the acquired pellicle, attachment to minute irregularities in the tooth surface, and attachment by direct contact with the tooth surface.

Which mode of calculus attachment is easiest to remove and which is hardest?

Attachment by pellicle is easiest (superficial, no interlocking); attachment to minute irregularities is hardest because the calculus becomes locked into the defects.

What is a problem with calculus attached by direct contact with the tooth surface?

It is prone to fracture during removal and may leave calculus crystals attached to the tooth, which can serve as a nidus for continued biofilm formation.

Why is calculus considered a secondary etiologic factor in periodontitis?

Because it acts as a reservoir for bacteria and endotoxins, while the unmineralized biofilm covering it is what likely initiates the immune response.

Why is meticulous subgingival biofilm debridement emphasized?

Complete removal of calculus is not feasible.

How is supragingival calculus detected?

Directly or with a mouth mirror, and by drying with compressed air to reveal small deposits that are invisible when wet.

List methods for detecting subgingival calculus.

Visual examination (dark edges or shadow under the gingiva), tactile examination with a probe or explorer (e.g., ODU 11/12), radiographs for large proximal deposits, and dental endoscopy.

Which type of calculus is smooth and difficult to detect with an explorer?

Veneer-type (thin, smooth veneer) calculus.

How do anticalculus dentifrices work, and what is their limitation?

They contain mineralization inhibitors such as pyrophosphates and zinc citrate that inhibit calculus crystal growth, but they do not affect existing calculus deposits.

Define extrinsic stain and intrinsic stain.

Extrinsic stain is on the external tooth surface and may be removed by brushing, scaling, or polishing; intrinsic stain results from changes in the structural composition or thickness of the tooth or is incorporated into the tooth structure.

Define exogenous and endogenous stain.

Exogenous stain originates from sources outside the tooth; endogenous stain originates from within the tooth.

Which stains are always intrinsic?

Endogenous stains.

What is exogenous intrinsic (internalized) stain?

Stain from an outside source that penetrates enamel defects or exposed dentin and becomes incorporated into the tooth after development.

What are the clinical features and cause of yellow stain?

A dull yellowish discoloration of dental biofilm, generalized or localized, more common in older adults and with inadequate self-care, linked to dietary sources and tobacco.

What causes green stain and who does it primarily affect?

Chromogenic bacteria and decomposed hemoglobin in the setting of poor oral hygiene, biofilm retention, and gingival hemorrhage; it is found primarily in childhood, most often on the facial gingival third of maxillary anterior teeth.

Describe black-line stain.

A highly retentive black or dark-brown line about 1 mm wide along the gingival third, made of chromogenic microorganisms in a ferric matrix, which tends to recur despite regular care and is associated with fewer cariogenic microorganisms.

What is tobacco stain and what is it composed of?

A light brown to dark leathery brown or black stain, often a tar-like band on lingual surfaces, incorporated in calculus and composed of tar and products of combustion.

Which agents and foods can cause brown extrinsic stain?

Tannins in tea, coffee, and soy sauce; stannous fluoride; chlorhexidine; betel/areca nut; and poor oral hygiene.

What causes the brown stain from stannous fluoride?

Formation of stannous sulfide or brown tin oxide from the reaction of the tin ion in the fluoride compound.

What interaction worsens chlorhexidine staining?

Chromogenic polyphenols in the diet such as coffee, tea, and wine.

What color is betel/areca nut stain?

Dark mahogany brown, sometimes almost black.

What is swimmer stain?

Yellowish or dark brown stain on the facial surfaces of incisors caused by frequent exposure to pools disinfected with chlorine or bromine.

What colors do copper, iron, nickel, and cadmium dust produce on teeth?

Copper: green or bluish-green; iron: brown to greenish-brown; nickel: green; cadmium: yellow or golden brown.

Why do pulpless or traumatized teeth discolor?

Blood and pulp tissue break down, and pigments from decomposed hemoglobin penetrate and discolor the dentinal tubules.

What is amelogenesis imperfecta?

A hereditary condition in which enamel is partially or completely missing due to a generalized disturbance of the ameloblasts, giving yellow to yellowish-brown teeth.

What is dentinogenesis imperfecta?

A hereditary condition of abnormal dentin caused by disturbances in the odontoblastic layer, making teeth appear translucent or opalescent, yellow-brown to blue-gray.

What causes dental fluorosis and how does it appear?

Ingestion of excessive fluoride during enamel mineralization damages ameloblasts; teeth range from chalky white spots to brown, and severe cases show cracks or pitting (mottled enamel).

How does tetracycline cause tooth discoloration?

It binds calcium and forms complexes with hydroxyapatite in developing mineralized tissue, producing light green to dark yellow or gray-brown discoloration, with or without banding.

When should tetracycline be avoided to protect developing teeth?

During pregnancy and in children up to age 12.

How does minocycline staining differ from tetracycline staining?

Minocycline can cause generalized blue-gray to gray intrinsic staining of permanent teeth after eruption.

What discoloration can silver amalgam cause?

A gray to black discoloration of the tooth structure around the restoration as tin migrates into enamel and dentin.

How can enamel erosion and attrition change tooth color?

Loss of enamel allows the yellow color of the underlying dentin to show through, making teeth look duller, gray, or yellow.

What are the guidelines for removing extrinsic stain?

Use brushing, interdental cleaning, debridement, and/or polishing with the most conservative approach and least abrasive polishing agent to avoid removing tooth structure, removing the fluoride-rich surface layer, or overheating the tooth.

What options exist for intrinsic stain since it cannot be scaled or polished off?

Whitening, microabrasion, and porcelain veneers or crowns for extensive deep staining.

What should be documented regarding soft deposits, calculus, and stain?

Clinical description of biofilm, materia alba, or food debris; extent (slight, moderate, heavy) and location of supra- and subgingival deposits; color, type, extent, and location of stains; and self-care procedures demonstrated, preventive measures discussed, and recall frequency.