exam 3 Flashcards
what is a primary risk factor for gingivitis, inflammatory periodontal diseases, and dental caries
dental biofilm
what is an integral aspect of the dental hygiene diagnosis?
assessment
heterotrophic microorganism that can live and grow in the presence of free oxygen, some are obligate, others facultative
aerobe
heterotrophic microorganism that lives and grows in complete( or almost complete) absence of oxygen; some are obligate, others facultative
anaerobe
dynamic, complex, multispecies communities of microorganisms that colonize the oral cavity/ unique characteristics allow biofilms to adapt to a variety of every changing environments; characteristics include: tenacious adherence to surfaces, protective EPS, three-dimensional structures with complex nutrient and communication pathways
biofilm
white or cream-colored “cheesy” mass that can collect over dental biofilm on unclean, neglected teeth; it is composed of food debris, mucin, bacteria sloughed epithelial cells.
materia alba
a thin acellular tenacious film formed of proteins, carbs, and lipids
acquired pellicle
where does pellicle tend to form
over exposed tooth surfaces and prostheses; pellicle is positioned as the interface between the tooth surfaces and the oral environment
where is pellicle thickest
near the gingival margin and areas undisturbed by the activities of chewing, swallowing, and speaking
how fast does pellicle form?
within minutes after eruption or after all soft and hard deposits have been removed from the tooth surfaces; fully formed within 30-90 minutes
what is composition of pellicle
glycoproteins that are selectively absorbed by the hydroxyapatite of the tooth surface
initial attachment of bacteria to the pellicle is by _____ ______ of microorganisms that originate from the oral mucosa
selective adherence
what has a high affinity for the hydroxyapatite tooth surface and initiate the process of pellicle formation
salivary proteins
____ _____ is continuous with the supragingival pellicle and can become embedded in tooth structure, particularly where the tooth surface is partially demineralized or rough from iatrogenic dentistry
subgingival pellicle
along with tooth surfaces, biofilm communities also form on :
oral mucosa, surfaces of tongue, and tonsils; their presence especially on the tongue and tonsils may contribute to malodor
during biofilm formation, organisms that colonize within the first few hours and primarily what kind?
gram positive cocci and rods
stages of biofilm formation: (5 stages)
formation bacterial multiplication and colonization matrix formation(EPS) biofilm growth maturation
in stage 4 of biofilm growth, enhancement of cell to cell communication process takes place, what is that called
quorum sensing
how is quorum sensing activated?
by specific genes located on the surface of bacterial cells within biofilm
what stage of biofilm formation is this? bacterial colonies mature and release planktonic cells to spread and colonize other areas within oral cavity; bacteria can disperse as single cells or in clumps
maturation stage 5
the pellicle, EPS, biofilm architecture, and resulting environment promote what organisms
anaerobic gram-negative bacterial growth activity
what day in biofilm formation is this? Early biofilm consists of primarily gram + cocci; streptococci, which dominate the bacterial population, include streptococcus mutans and streptococcus sanguis
day 1-2
what happens day 2-4 of biofilm formation?
- cocci still dominate, more gram + filamentous form and slender rods join surface of cocci colonies
- more filamentous forms grow into the cocci layer and replace many of the cocci
- people who form biofilm slowly will exhibit more cocci and fewer filamentous forms
mixed flora appears comprised of rods, filamentous forms, and fusobacteria
-biofilm near gingival margin thickens as more mature flora develops; gram - spirochetes and vibrios proliferate; as biofilm spreads coronally, newer/younger biofilm primarily coccal
days 4-7
what days in biofilm formation does vibrios and spirochetes appear, along with the white blood cells increasing and inflammation(can be observed in gingival tissues)
days 7-14
for days 14-21 of biofilm formation, which organisms are most prevalent?
vibrios and spirochetes
what day is this of biofilm formation: densely packed filamentous microorganisms can arrange themselves perpendicular to the tooth surface in a palisade; biofilm matures and thickens, more gram - anaerobes appear, which are protected by the biofilm architecture and environment; gingivitis is evident clinically
days 14-21
supragingival flora is predominately what organisms?
gram positive aerobes
what species populate early “healthy” supragingival biofilm
streptococcus and actinomyces species closely aligned with lactobacillus and candida species as flora matures
subgingival flora is predominantly what organisms?
gram negative anaerobes and motile organisms of periodontal disease
what organisms are found in subgingival biofilm
actinomyces, tanneralla forsythia, fusobacterium nucleatum and cluster of B-cytophagflavo bacterium-bacterodes
a disease of the dental calcified structures(enamel, dentin, and cementum) characterized by demineralization of the mineral components and dissolution of the organic matrix
dental caries
which organisms are cariogenic?
strep mutans and streptococcus sobrinus and lactobacilli
which organism initiates and the caries process and which contributes to the progression of a carious lesion
mutans
lactobacilli
how long does it take to get pH back to normal?
1-2 hours
what is biofilm pH before eating?
6.2-7.0; pH is lower is the caries susceptible person and higher in caries resistant person
what is the critical pH for enamel demineralization
4.5-5.5
what is the critical pH for root surface demineralization is
6.0-6.7; especially relevant for patients with multiple areas of recession and xerostomia
what makes materia alba different from biofilm?
materia alba is unorganized, biofilm is organized
dental biofilm mineralized by crystals of calcium phosphate mineral salts between previously living microorganisms
calculus
on clinical crowns coronal to the margin of the gingiva; on implants, complete and partial dentures(calculus)
supragingival calculus
most frequent site of supragingival calculus
lingual surfaces of mandibular anterior teeth and facial surfaces of maxillary first and second molars, opposite the openings of the ducts of the submandibular and parotid salivary glands,and on crowns of teeth out of occlusion, nonfunctioning teeth, teeth neglected during daily biofilm removal, dentures, prostheses and tongue piercings
on the clinical crown apical to the margin of the gingiva and extending nearly to the clinical attachment on the root surface and on dental implants, (calculus)
subgingival calculus
sources of minerals for supragingival calculus
saliva
sources of minerals for supragingival calculus
gingival crevicular fluid and inflammatory exudate supply the minerals for the subgingival deposits
biofilm accumulates on _____ anterior mandibular teeth
crowded
biofilm develops more rapidly on rough or smooth tooth surfaces?
rough; attach easier on calculus, poorly contoured restorations, and removable appliances
deposits of biofilm may extend over an entire crown of a tooth that is ______, out of occlusion, or not actively used during mastication
unopposed
which inorganic elements are common in biofilm
calcium, phosphorus, magnesium are more concentrated in biofilm than in saliva and also fluoride
what organic elements are common in biofilm?
carbohydrates and proteins
coronal to the gingival margin, what kind of biofilm is that?
supragingival biofilm
forms on the external surfaces of the oral epithelium and attached gingiva, what kind of biofilm is that?
gingival biofilm
located between the epithelial attachment and the gingival margin, within the sulcus or pocket, what location of biofilm is that?
subgingival biofilm
what kind of biofilm develops in pits and fissures of the teeth?
fissure biofilm
the major inorganic components of calculus are:
calcium, phosphorus, carbonate, sodium, magnesium, and potassium
about 2/3 of the inorganic content of calculus is made up of
crystals, hydroxyapatite, it also contains various amounts of bryshite, whitelockite, and octacalcium phosphate
what is the most highly mineralized tissue in the body; contains 95-97% inorganic salts
dental enamel
what percentage of inorganic salts does dentin have
65%
what percentage of inorganic salts does cementum have
45-70%
mature calculus has app. how much inorganic content
70-80%
