1. Biology of Dental Plaque I Flashcards
The Founding Father of Oral Microbiology
Antony van Leeuwenhoek
Stains
Pigmented deposits found on or within structures of the teeth.
- Intrinsic stains: ____
- Extrinsic stains: ____
Intrinsic stains > pigmented deposits found within the teeth itself > tetracycline staining (antibiotic that has an affinity for ____); if exposed to tetracycline during development, it will bind to calcium and you will see a ____ deposition along the teeth (acts like a “tree”, can see when at what point an individual was exposed); can place veneers to fix, cannot ____
Extrinsic stains > deposits accumulate on teeth > chlorhexidine (antibacterial rinse used in periodontics when patient not asked to clean teeth for week to two) > completely ____ response from patient to patient > chlorihexidine kills plaque bacteria and causes them to release their ____ (it’s not due to the drug, it’s due to the presence of ____); smoking, excessive coffee, red wine, pop, etc.
Removed very easily ____, while the intrinsic stains cannot
tetracycline
chlorhexidine
calcium
linear
bleach
heterogenous
pigments
bacteria
(chlorhexidine)
Materia Alba
Unstructured accumulation of bacteria, host cells and food debris that is ____ attached to the teeth and is thus easily removed with a blast from an ____ syringe
Represents patient’s last two or three ____
loosley
air-water
meals
Dental Plaque
A highly ____ accumulation of bacteria and their extracellular products ____ attached to the surfaces of teeth, dental restorations and soft tissue that can only be removed ____
Difference between this and materia alba: has to be ____ removed (not simply by air-water syringe)
On surface of ____ > find dental plaque; exists at gingival margin and extends down further into the gingival environment
structured
tighlty
mechnically
mechnically
calculus/tartar
Calculus (Tartar)
Calcified dental plaque that is usually covered by a layer of ____
Dental plaque = ____
uncalcified plaque
uncalcified
Color depends on the ____; and on whether they smoke > smoker’s have ____ types of calculus
diet
darker
No ____ present between relative amount, location and color of plaque/calculus to extent of caries and/or attachment loss
correlation
Dental Plaque
Supragingival > forms on surfaces of teeth that seat above ____; no ____ disease > sitting on enamel over crown; if you have recession > forms on cementum covering root surfaces
Subgingival > gingival crevice, or ____
The compositions of these two types of plaque are very ____ from one another
gingival margin
periodontal
periodontal pocket
different
Characteristics of Dental Plaque
- Tenacious microbial deposits that form on teeth, dental restorations and soft tissues of the oral cavity
- Composed of mainly ____ and their products and to a lesser extent, entities derived from the the host (mostly ____ molecules).
- Highly ____ structure and formed via a very ____ process.
- You can find dead host cells and substances released by host cells, but predominantly it is of ____l in origin
bacteria
salivary
organized
orderly
Characteristics of Dental Plaque
- The microbial composition of plaque can ____ between individuals, different ____ of the same individual and even different sites on the same tooth.
- There is variability in the ____ of distinct types of plaque. Certain are well tolerated by the host while others can cause caries and/or periodontal disease.
- Plaque is a bacterial ____.
- ____ > well tolerated by the host, may cause gingivitis and dental caries; ____ > important in induction of periodontal disease; has to do with different types of bacteria found within these types of plaque
- Looking at plaque as biofilm has changed philosophies in treatment
vary
teeth
pathogenicity
biofilm
supragingival
subgingival
Characteristics of Dental Plaque
- A key component to successful dental therapy is getting patients to carry out ideal ____!
plaque control
The History of Oral Microbiology
A lot of what we know upon dental plaque is based upon the evolution of technology
Started with von Leewonhoek > 1890’s: ____ microscopes (more advanced) and found more types of bacteria > dark field microscopy in 1960 > major advance: late 70’s up to mid-80’s, culturing ____ bacterium (organisms in dental plaque are facultative or pure anaerobic bacteria) > integration of molecular technology into oral biology ____ but most dramatic was the ____ sequencing technology and ____ > confirmed the complexity of oral bacteria
light anaerobic (PCR) 16S rRNA next generation sequencing
Plaque Bacteria: Members of the Human Microbiome
A microbiome is “the ____ of commensal, symbiotic and pathogenic microorganisms that literally share our body space”. - Joshua Lederberg
The human microbiome:
- the “normal flora”
- microbial cells outnumber human cells by ____
- variability in composition ____ and ____ individuals
- many are ____, others potentially ____
Does appear to be a ____ that we all share (same may be true in oral cavity)
ecological community 10:1 between within beneficial pathogenic
core microbiome
The Oral Microbiome
The oral microbiome is defined as “all of the microorganisms that are found on or in the ____ and it’s contiguous extensions (stopping at the ____)”.
This includes the teeth, gingival sulci, attached gingiva, tongue, cheeks, inner aspect of the lip, hard palate, soft palate, tonsils, pharynx, trachea, Eustachian tube, middle ear, lungs, nasal passages, sinuses and proximal esophagus.
Context of oral microbiome applies to all these structures (including the odd ones: ____ tubes, ____, etc.)
oral cavity
distal esophagus
eustachian
middle ear
The Oral Microbiome
Microbiome of the oral cavity:
- Contains viruses, protozoa, fungi, Archae and bacteria
- Saliva contains on the order of ____ bacteria/ml; we swallow approximately ____ grams of bacteria/day
- Approximately ____ species of bacteria have been cultured from the human oral cavity.
- Data coming from studies utilizing high-throughput next generation DNA sequencing indicate that between ____ species of bacteria inhabit the human oral cavity
- Only the microbiome of the ____ appears to exhibit more complexity relative to that of the oral cavity.
- The oral microbiome of each person contains ____ organisms
- There is variability in the composition of the microbiome between individuals but there does appear to be a ____ common to most individuals
10^0 5 350 600-1000 colon 100-200 core microbiome
Acquisition of the Oral Microbiome
- Oral colonization may begin in ____ but clearly starts in the ____.
- A few hours after birth, organisms from the mother’s ____ and possibly the external environment are establish within the newborn’s mouth.
- Within 24 hours the “pioneering” microorganisms (____) are established by binding to mucosal surfaces.
- By approximately the ____ month after birth, the composition of the infant’s oral microbiome may be distinct from that of the mother’s due to acquisition of bacteria from external sources via ____ and contact with other ____ (and ____).
Oral colonization begins as passes through birth canal (____)
This process happens very quickly
Household with pets may contribute to the microbiome of a newborn
utero birth canal mouth gram-positive, facultative fifth feeding humans pets
non-sterile
Development of the Oral Microbiome
- The next major event is the eruption of teeth that provide a non-shedding surface for bacterial colonization.
- The teeth serve as a novel niche for organisms that prefer to colonize ____ tissues.
- Formation of the gingival crevice yields a niche that favors colonization by organisms preferring an ____environment
- At three years of age, the salivary microbiome is complex but continues to mature until ____
- During puberty, ____ changes affect the composition of the microbiome inducing a transition to an “adult” microflora
hard
anaerobic
adulthood
hormonal
Development of the Oral Microbiome
- Over time, the oral microbiome continues to diversify until it becomes a stable ____ community.
- This represents a state of equilibrium between the ____ microflora and ____ conditions
- The composition of the oral flora then tends to be relatively stable but can be influenced by ____, hormonal fluctuations, ____ and transmission of microorganisms between individuals
- There appear to be specific changes in the composition of the oral microbiome of ____ individuals. However, this needs to be verified by further research.
climax resident local environmental diet oral hygiene dentate elderly individuals
Development of the Oral Microbiome
- Total edentulism results in a microflora similar to that of ____.
- Insertion of ____ provide non-shedding surfaces that result in reestablishment of a ____ microflora and the accumulation of ____ (____ species in particular).
- Implant-supported prostheses result in the reestablishment of both a ____ and ____ microflora.
infants dentures supragingival yeast Candida
supra-
subgingival
Development of the Oral Microbiome
Left: demonstrates acquisition of microbiome in infant and older child > and gives rise to a core human microbiome; authors looked at microbiome of 20 healthy individuals, and used sequencing > organisms present in large proportion: bold is 80%, and 10% of sequence, the others found in 75% of samples and 1% of sequences obtained; each different structure in oral cavity harbor different types of organisms (some are shared, but definitely unique organisms that associate within oral cavity)
LOOK OVER THE CHART
Connection of the Oral Microbiome with Systemic Disease
and others:
- ____ pregnancies
- Systemic AID
- ____ diseases
- Oral cancer
- ____ cancer
- Pancreatic cancer
- ____
What happens in mouth has systemic implications that can explain how bacteria/bacterial products enters the bloodstream and affects the host
All components of host immune response have effects on part of body
Association between phenomena in oral cavity to those listed in list and on chart
pre-term low birthweight
respiratory
colon
erectile dysfunction
Bacterial Biofilms
“Matrix-enclosed bacterial populations that are ____ to each other and/or to surfaces or substrates.”
This is in contrast to when bacteria are found as single cells that may float or swim in some type of fluid (i.e., saliva) and living in what is referred to as their ____ state.
adherent
planktonic
Bacterial Biofilms
Bacterial organisms naturally found within a biofilm behave ____ relative to when grown as a laboratory isolate!
Behavior of laboratory isolate may not correspond to the way the organism behaves in its natural biofilm (may be artifactual)
Examine how organisms act in ____ in a biofilm (naturally)
differently
vitro
Characteristics of Bacterial Biofilms
- May contain a ____ or ____ bacterial species.
- Composed of multiple ____.
- Numerous distinct ____ exist within a biofilm each with radically different pHs, oxygen concentrations, temperatures and electrical potentials.
- These are related directly to the ____ concentrations
Bacterial biofilms do not only contain bacteria, also contain ____ and ____ organisms (but bacteria are predominant)
single
multiple
“micro” communities
microenvironments
oxygen
viruses
fungal
Characteristics of Bacterial Biofilms
- Biofilms exhibit primitive ____.
- Biofilm bacteria exhibit metabolic ____ and/or ____
- Bacteria living within a biofilm are relatively resistant to typical host ____ mechanisms.
- Bacteria living within a biofilm are relatively resistant to ____-and ____-delivered antimicrobial agents
"circulatory systems" cooperativity antagonism defense systemically locally
Microbial Ecology
The study of the interrelationships between microorganisms and the world around them including:
- interactions between ____
- interactions between microbes and their ____
- interactions between microbes and their ____
How come normal flora isn’t eliminated by immune system? Why doesn’t our body react against them? > the responses against bacteria and can change the local environment and change the composition of the microflora (current concept of how bacterial plaque is involved in the induction of periodontal disease)
microbes
environment
host
Microbial Ecology
Symbiotic Relationships
Two dissimilar organisms (micro and or macro) living together in more or less intimate association or close union. Organisms living in a ____.
Symbiotic > describes situation in which two species of bacteria live in close proximity with one another; the below are all types of symbiotic relationships:
____ > neither one benefits from the other, doesn’t need the other whatsoever
____ > one benefits, but the other is completely unaffected
____ > both benefit (need presence of other in order to thrive) > utilization of same nutrient source, or metabolic byproduct that benefits one, and byproduct that supports anaerobic organism, etc.
____ > kills or harms the other, the killer is not affected (not the same as ____)
____ > can have significant effects on host (the biology) within the oral cavity
symbiont
synergism commensalism mutualism antagonism parasitism
commensalism/mutualism
The Oral Ecosystem
The oral cavity is composed of a number of potential habitats that due to unique environment factors support the growth of distinct groups of microbes
These include:
- ____ mucosal surfaces
- ____ of the tongue
- gingiva (including ____ mucosa)
- teeth
- ____ crevice
- dental restorations
- ____ appliances
All of the environments differ with temp, pH, nutrient availability, redox potential, etc. > determine which ____ grow in a site
buccal and alveolar dorsum palatal gingival orthodontic
bacteria
The Oral Ecosystem
Top left: talks about bacteria relative to periodontal disease
Bottom left: talks about bacteria relevance to caries > bacteria that are found on each different surface differs > the decay in different areas you see differs in ____, how they progress, whether they progress (both supra- and subgingivally) > manifestation of different environmental conditions
Right > saliva, teeth (fissure plaque vs smooth surface), tongue, gingiva, dental material > different ____ found in each niche
rate
organisms
Relevance of Biofilms to Medicine and Dentistry
Conditions related to biofilms > bacterial ____ (colonize valves of heart, derived from oral microflora), ____ (lungs), chronic wounds, infections of ____ device (catheters, or central lines), and biggest problem with ____ devices are infections that develop secondary to placement of device (grow as biofilms)
Worm-like structures > biofilms > lines of ____ units
endocartitis cystic fibrosis medical orthopedic dental
Characteristics of Bacterial Biofilms
- May contain a ____ or ____ bacterial species.
- Composed of multiple ecological ____.
- Numerous distinct ____ exist within a biofilm each with radically different pHs, [oxygen], temperatures and electrical potentials.
- Biofilms exhibit primitive ____
- Biofilm bacteria exhibit ____ cooperativity.
- Bacteria living within a biofilm are relatively resistant to typical host ____ mechanisms.
- Bacteria living within a biofilm are relatively resistant to systemically
locally-and-delivered ____ agents.
single multiple "micro" communities microenvironments "circulatory systems" metabolic defense antimicrobial
Multispecies Bacterial Biofilms
Dental plaque is a very unique type of multispecies biofilm in that it forms on a ____ surface, a tooth (or dental restoration).
Biofilm formation is a ____ and ____ process that requires ____ of the surface onto which the bacteria will attach.
Non-shedding makes it unique compared to other biofilm formation
A > conditioning of substrate; B > initiation; C > maturation; D > mature, where organisms detach from matrix and enter nearby fluid and disseminate
Biofilm = ____
highly organized
dynamic
conditioning
multispecies
Numerous Distinct Microenvironments Within Biofilms
The local environments in biofilms have unique characteristics that select for the growth of distinct bacterial species. Key factors include:
- ____
- ____ potential (anaerobiosis)
- ____
- ____ sources
Host and bacterial processes affect the characteristics of the microenvironment and in doing so can induce alterations in the microbial composition of the biofilm.
Tooth > surface of enamel; the environmental conditions are very different from the ones located further out > due to the ones in the list (redox potential is an ____ measure of the presence/absence of ____)
Formation of oxygen gradient > more oxygen present at the surface of the plaque, and the ones located outward have greater accessibility, bacteria located internally will be much different based on their ____
temperature
redox
pH
nutrients
indirect
oxygen
growth pattern
