Tooth Accumulated Materials PDF

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Tooth accumulated materials: 1. 2. 3. 4.

Acquired pellicle Materia alba Microbial plaque Dental calculus – tartar

1) Acquired pellicle     

Translucent, thin, homogenous, acellular (free from bacteria and other cell forms. Adheres to surfaces of teeth, restorations, calculus & other firm surfaces of oral cavity Called salivary glycoproteins (what it is made of) Develops minutes after tooth brushing Glycoproteins are absorbed via hydroxyapatite crystals (highly insoluble coating over teeth.)

Structure:  Exhibits histochemical and ultra-structural features  Stains positive for sugars and proteins  Does not bind dyes  Does not contain heme or melanin  Brown in color due to tannins  Primarily made of glycoproteins from the saliva Function:  Provide a barrier against acids, thus may aid in reducing dental caries formation  Participates in plaque formation Hypothesis on pellicle formation: 1. Acid precipitation:  Micro-organisms produce acids which colonize the tooth surface which leads to salivary glycoprotein precipitation  Very unlikely (pellicles are acellular) 2. Enzymatic enhancement:  Salic acid- found at terminal end of salivary glycoprotein (sgp)- enhances the solubility of protein at neutral.  This lowers the isoelectric point  Leads to precipitation of salivary glycoprotein 3. Selective absorption:  Sgp rich in salic acid are selectively absorbed via hydroxyapatite crystals. Types of pellicle: 1. Subsurface pellicle – found interproximally 2. Surface pellicle- lingual/buccal/palatal 3. Stained pellicle- stains from external sources – can be seen with the naked eye Supragingival pellicle – above pellicle, derived from saliva Subgingival pellicle – derived from gingiva cercucular fluid (gcf)

Significance of pellicle:  Protective  Lubrication  Attachment for bacteria and calculus.

2. Materia alba   

Informal accumulation of loosely adherent, unstructured white/grayish white masses of oral debris & bacteria Forms all over all surface of mouth Removed with vigorous rinsing and water irrigation.

Effects:  Causes gingival inflammation due to high bacteria count  Demineralizes tooth surface  Causes dental caries

3.dental plaque aka microbial plaque      

It is dense, organized bacterial system embedded in an intermicrobial matrix Loosely adheres to all surfaces of the mouth Water irrigation only removes outer layer 500 – 700 species of bacteria in 1g of plaque Forms 24 hours after brushing After 48 hours, it is visible with naked eye

Classification:  2 groups: I. Supragingival- above gingival margin II. Subgingival - below gingival margin (sulcus/pocket)  Also, described as:  Pits and fissure plaque  Black stained plaque Clinical appearance I. Supragingival:  White, yellowish layer along gingival margin of tooth  Increases rapidly when not brushed. II. Subgingival:  Not easily diagnosed clinically  Occurs below gingival margin  Observed due to staining Structure and composition:  Varies according to:  Age  Extent of malnutrition  Location  Diet

First cellular material of plaque: Consist of:  Predominant coccal bacteria  Small amounts of epithelial cells and leucocytes  Extracellular matrix  As plaque matures:  Filamentous bacteria attach  Coccoid bacteria attach to filamentous bacteria Extracellular matrix of plaque:  Contains bacteria and salivary products  Acts as a framework to bind micro-organisms  Extracellular storage for fermentable carbohydrates  Alters the diffusion of a substance into and out of plaque  Contains numerous toxic substances. Absence of bacteria: 2 stages: 1. Revisable stage:  Adheres to tooth with h-bonds and electrostatic and attractions. 2. Irreversible stage:  A firmer specific adhesion of bacteria to tooth surface. Gram negative (-) consist of:  Predominate  High level of protein  Carbohydrates  Lipids Formation of plaque: Phase 1:  Consist of gram positive organisms (coccoid, rod forms , norcadia)  3 days Phase 2:  Decrease in coccoid forms  More mixed bacteria – rods/filaments/spirochaetes  6 -10 days Phase 3:  Increase in gram negative anaerobes  Anaerobes form best in absence of o2(oxygen)  Forms a bio-film (tightly packed masses with moving bacteria)

4.dental calculus/tartar      

Important in development of P.D Plaque that has been mineralized Deposits of calcium and phosphate cells that become unstable Only removable by a dental professional Forms when the matrix and micro-organisms calcify Plaque is a causative agent.

Classification: 1. Supragingival  Also, called:  Supramarginal  Extra gingival  Coronal  Salivary 2. Subgingival  Also, called:  Sub marginal  Serumal Clinical appearance 1. Supragingival:  Yellow/white in color  Darkens with age  Can develop secondary staining  Found on crowns of teeth  Found above gingival margin  Largest amounts at salivary glands  First in upper molars  Lingual to lower anterior  Reoccurs after removal  Moderately hard  Clay-like  Surface has non-mineralized plaque 2. Subgingival:  Brown/black  Forms a ring around teeth  Stains are due to blood pigment  Found interproximally  Found below gingival margin in sulcus or pockets  Normally flat due to pocket pressure  Contains calcium, magnesium and fluoride  No salivary proteins Diagnosis:  Clinical inspection  Use of explorer probe  Use of 3-in-1 syringe to observe pockets  Radiograph examination  Flossing Formation: 3 stages 1. Initial attachment of bacteria via acquired pellicle 2. Growth and organization of bacteria on acquired pellicle 3. Mineralization of plaque

Structure and formation:  Layered structure  Predominantly needle shaped crystals  Crystals randomly arranged  Surface layer covered by non-mineralized plaque  Plaque serves as organic matrix for the mineralization  Mineralization occurs in intercellular matrix  Progresses until entire matrix crystallizes  Then followed by bacterial cells Attachment to teeth: 1. - underlying pellicle has calcified 2. - surface irregularities are also penetrated by crystals of calculus Mineralization theories: 1. Bacterial theory 2. Carbon dioxide theory 3. Epitaxis theory Bacterial theory:  Bacteria cells produce metabolic products  When they are toxic they destroy bacteria CO2 theory:  Escape of CO2 from saliva causes pH to rise  Crystallization occurs which form into tartar  Everything happens near salivary ducts. Epitaxis theory:  Crystal formation through seeding by another compound  Compound has similar molecular configuration as hydroxyapatite  Thus Ca salts precipitates...