This document provides an overview of biofilms in dentistry. It defines biofilms and discusses their importance, describing the basic structure and characteristics of biofilms including the extracellular polymeric substance matrix, microcolonies, and fluid channels. The document outlines the stages of biofilm development and characteristics such as resistance to antimicrobials. It discusses the role of biofilms in dental diseases like caries and endodontic infections. It also reviews current hypotheses around the role of biofilms in caries development and prevention strategies.
Biofilms on the teeth are the root cause of inflammation on the gums and periodontium. Understanding the formation of biofilms will make improve our treatment modalities towards disruption of biofilms hence provide better periodontal health to our patients at large.
Diseases of the pulp:Part 1- Development, Physiology, Histology of Dental PulpDeepthi P Ramachandran
The development, physiology, histology of the dental pulp is briefly discussed. The features of the pulp as a connective tissue, its cells,fibers, innervation, vascularity are dealt with
Biofilms on the teeth are the root cause of inflammation on the gums and periodontium. Understanding the formation of biofilms will make improve our treatment modalities towards disruption of biofilms hence provide better periodontal health to our patients at large.
Diseases of the pulp:Part 1- Development, Physiology, Histology of Dental PulpDeepthi P Ramachandran
The development, physiology, histology of the dental pulp is briefly discussed. The features of the pulp as a connective tissue, its cells,fibers, innervation, vascularity are dealt with
Introduction……
Uterus……..Sterile
After birth……… few facultative & aerobic microorganisms
Second day……... anaerobic
2 weeks …….. Nearly mature microbiota
> 2 years …….. 400 different spp (10 14 )
After tooth eruption …… > 500 spp.
Any individual contains ≥150 spp.
6 Ecological niches
Or
Microbial habitats within the mouth
EARLYCOLONIZERS
Dental plaque
Formation
2. Specific Plaque Hypothesis
Only certain plaque is pathogenic, and its pathogenicity depends on the presence of or increase in specific microorganisms.
This concept predicts that plaque harboring specific bacterial pathogens results in periodontal disease because these organisms produce substances that mediate the destruction of host tissues.
3. Ecological plaque hypothesis
In 1990, PD Marsh et al developed the ecologic plaque hypothesis
According to this, both the total no. of dental plaque and the specific microbial composition of plaque may contribute to the transition from health to disease.
A change in the nutrient status of a pocket or chemical and physical changes to the habitat are thus considered the primary cause for overgrowth by pathogens.
The mouth, like all external surfaces of the body and the gut,
has a substantial microflora living in symbiosis with a healthy
host.
• The microflora of the mouth contains hundreds of species of
aerobic and anaerobic bacteria.
• Cultural studies indicate that more than 500 distinct microbial
species can be found in dental plaque.
5
• Although bacteria are necessary for periodontal disease to
take place, a susceptible host is also needed.
• The immune-inflammatory response that develops in the
gingival and periodontal tissues in response to the chronic
presence of plaque bacteria results in destruction of
structural components of the periodontium leading,
ultimately, to clinical signs of periodontitis.
6
• The host response is essentially protective, but both
hyporesponsiveness and hyper-responsiveness of certain
pathways can result in enhanced tissue destruction (Bruce
Pihlstrom 2005 ).
• Closer investigations of the destructive pathway of periodontal
disease began to focus on the relation-ship between bacteria
and the host response in the initiation and progression of
periodontal disease.
7
• This shift in etiological theory produced a paradigm that
called attention to the fact that although microorganisms are
the cause of periodontitis, the clinical expression of the disease
depends on how the host responds to the extent and virulence
of the microbial burden.
• It was found that degradation of host tissue results from this
bacterial-host interaction.
Bioactive materials are revolutionizing oral health care and the quest for newer materials is never ending especially in the field of dental science. Research on biomaterials intensely involves interdisciplinary contributions from several major areas and requires extensive knowledge of medical science, materials science, biochemistry, biomedical engineering and clinical science. They are broadly used in the field of conservative dentistry and periodontics for regeneration, repair and reconstruction by acting directly on the vital tissue inducing its healing and repair through induction of various growth factors and different cells. This article reviews on the properties and clinical application of newer bioactive materials in endodontics, with a primary focus on the biocompatibility and tissue response to these materials.
Antimicrobial Defense System in Saliva, Antioxidant Role of Saliva, Maintenance of pH, Maintenance of Mucous Membrane Integrity, Maintenance of Ecological Balance, Maintenance of Tooth Integrity, Debridement & Lavage, Soft Tissue Repair, Saliva & Dental Caries, As Diagnostic Marker.
,
Introduction……
Uterus……..Sterile
After birth……… few facultative & aerobic microorganisms
Second day……... anaerobic
2 weeks …….. Nearly mature microbiota
> 2 years …….. 400 different spp (10 14 )
After tooth eruption …… > 500 spp.
Any individual contains ≥150 spp.
6 Ecological niches
Or
Microbial habitats within the mouth
EARLYCOLONIZERS
Dental plaque
Formation
2. Specific Plaque Hypothesis
Only certain plaque is pathogenic, and its pathogenicity depends on the presence of or increase in specific microorganisms.
This concept predicts that plaque harboring specific bacterial pathogens results in periodontal disease because these organisms produce substances that mediate the destruction of host tissues.
3. Ecological plaque hypothesis
In 1990, PD Marsh et al developed the ecologic plaque hypothesis
According to this, both the total no. of dental plaque and the specific microbial composition of plaque may contribute to the transition from health to disease.
A change in the nutrient status of a pocket or chemical and physical changes to the habitat are thus considered the primary cause for overgrowth by pathogens.
The mouth, like all external surfaces of the body and the gut,
has a substantial microflora living in symbiosis with a healthy
host.
• The microflora of the mouth contains hundreds of species of
aerobic and anaerobic bacteria.
• Cultural studies indicate that more than 500 distinct microbial
species can be found in dental plaque.
5
• Although bacteria are necessary for periodontal disease to
take place, a susceptible host is also needed.
• The immune-inflammatory response that develops in the
gingival and periodontal tissues in response to the chronic
presence of plaque bacteria results in destruction of
structural components of the periodontium leading,
ultimately, to clinical signs of periodontitis.
6
• The host response is essentially protective, but both
hyporesponsiveness and hyper-responsiveness of certain
pathways can result in enhanced tissue destruction (Bruce
Pihlstrom 2005 ).
• Closer investigations of the destructive pathway of periodontal
disease began to focus on the relation-ship between bacteria
and the host response in the initiation and progression of
periodontal disease.
7
• This shift in etiological theory produced a paradigm that
called attention to the fact that although microorganisms are
the cause of periodontitis, the clinical expression of the disease
depends on how the host responds to the extent and virulence
of the microbial burden.
• It was found that degradation of host tissue results from this
bacterial-host interaction.
Bioactive materials are revolutionizing oral health care and the quest for newer materials is never ending especially in the field of dental science. Research on biomaterials intensely involves interdisciplinary contributions from several major areas and requires extensive knowledge of medical science, materials science, biochemistry, biomedical engineering and clinical science. They are broadly used in the field of conservative dentistry and periodontics for regeneration, repair and reconstruction by acting directly on the vital tissue inducing its healing and repair through induction of various growth factors and different cells. This article reviews on the properties and clinical application of newer bioactive materials in endodontics, with a primary focus on the biocompatibility and tissue response to these materials.
Antimicrobial Defense System in Saliva, Antioxidant Role of Saliva, Maintenance of pH, Maintenance of Mucous Membrane Integrity, Maintenance of Ecological Balance, Maintenance of Tooth Integrity, Debridement & Lavage, Soft Tissue Repair, Saliva & Dental Caries, As Diagnostic Marker.
,
Introduction to biofilm
Examples of biofilm
Form of biofilm
Discovery of biofilm
Properties of biofilm
Composition of biofilm
Formation of biofilm
Bacterial biofilm
Impact of biofilm
Problem caused by biofilm
Uses of biofilm
Antibiotic Tolerance/Resistance Of Bacterial Biofilms
Antibiofilm approach
Control strategies of Biofilm
The immobilization of whole cells can be defined as “the physical confinement or localization of intact cells to a certain region of space, without loss of desired biological activity.”
In other words, cell immobilization means to freeze an entire cell in a state of suspended animation, such that its metabolism stops and hence does not die.
Biological films are the multilayer growth of cells on solid support surfaces ; community of micro-organisms enclosed in a polymeric matrix and adhered on inert or living surface
These attached cells are embedded in a self-produced exopolysaccharide matrix, and exhibit different growth and bioactivity compared with suspended cells.
Biofilm consists of three components:
microorganism, extracellular polymeric substances (EPS),
surface for attachment.
The excreted polymeric substances hold the biofilm together and cement it to a surface.
The thickness of a biofilm is an important factor affecting the performance of the biotic phase.
Thin biofilms - low rates of conversion due to low biomass concentration.
Thick biofilms - may experience diffusionally limited growth, which may or may not be beneficial depending on the cellular system and objectives
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
The presentation covers the whole aspect of Endodontic biofilm and its management in a clinical practice.
Right from definition to formation to its classification and its removal using various irrigants and techniques. Its microscopic structure. And role of E. Fecalis in biolfilm. Its also explains qurorom sensing very well
Biofilms are common in the natural world.
Biofilms are a collective of one or more types of microorganisms that can grow on many different surfaces.
The vast majority of the earth’s microorganisms (99 %) live in biofilms.
Microorganisms that form biofilms include bacteria, fungi, algae and some enteric viruses.
The biofilm matrix is an important part of the biofilm containing the microbial cells, exopolysaccharides, and water.
Usually, the microbial cells in a biofilm are embedded in the extracellular polymeric substances (EPS) Produced by themselves which is also called Slime.
EPS contains extracellular DNA, proteins, and polysaccharides which form slime.
Microbial cells in the biofilm are different from the planktonic cells that are single cells and can float on a liquid medium.
Microorganisms cause virtually all pathoses of the pulp and periapical tissues.
Once bacterial invasion of pulp tissues has taken place, both non-specific inflammation and specific immunologic response of the host have a profound effect on the progress of the disease.
Endodontic infection develops in root canals devoid of host defenses,
pulp necrosis (as a sequel to caries, trauma, periodontal disease,or iatrogenic operative procedures)
or pulp removal for treatment.
Biofilm-induced oral diseases.
ROUTES OF ROOT CANAL INFECTION
Caries
• Trauma-induced fractures
• Cracks
• Restorative procedures
• Scaling and root planing
• Attrition
• Abrasion
• Gaps in the cementoenamel junction
at the cervical root surface
• Dentinal tubules
• Direct pulp exposure
• Periodontal disease
• Anachoresis
Mechanisms of Microbial Pathogenicity and Virulence Factors
Pathogenicity : The ability of a microorganism to cause disease.
Virulence: Degree of pathogenicity of a microorganism.
Some microorganisms routinely cause disease in a given host and are called primary pathogens.
Other microorganisms cause disease only when host defenses are impaired and are called opportunistic pathogens by changing the balance of the host–bacteria relationship.
Bacterial strategies that contribute to pathogenicity include the ability to coaggregate and form biofilms.
In the pathogenesis of primary apical periodontitis
Bacteria in caries lesions form authentic biofilms adhered to dentin.
Diffusion of bacterial products through dentinal tubules induces pulpal inflammation
After pulp exposure, the exposed pulp tissue is in direct contact with bacteria and their products
and responds with severe inflammation. Some tissue invasion by bacteria may also occur.
Bacteria in the battlefront have to survive the attack from the host defenses and at the same time acquire nutrients to keep themselves alive.
In this bacteria–pulp clash, the latter invariably is “defeated” and becomes necrotic, so bacteria move forward and “occupy the territory”—that is, they colonize the necrotic tissue.
These events advance through tissue compartments, coalesce, and move toward the apical part of the canal until virtually the entire root canal is necrotic and infected.
At this stage, involved bacteria can be regarded as the early root canal colonizers or pioneer species (play an important role in the initiation of the apical periodontitis disease process, modify the environment, making it conducive to the establishment of other bacterial groups)
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
Andreas Schleicher presents at the OECD webinar ‘Digital devices in schools: detrimental distraction or secret to success?’ on 27 May 2024. The presentation was based on findings from PISA 2022 results and the webinar helped launch the PISA in Focus ‘Managing screen time: How to protect and equip students against distraction’ https://www.oecd-ilibrary.org/education/managing-screen-time_7c225af4-en and the OECD Education Policy Perspective ‘Students, digital devices and success’ can be found here - https://oe.cd/il/5yV
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
2. Contents
• Biofilm - Definition
• Introduction
• Ultrastructure of Biofilm
• Development of Biofilm
• Characteristics of Biofilm
• Significance of Biofilms
• Cariogenic biofilms
• Ultrastructural changes in enamel related to the biofilm
• Current hypotheses to explain the role of plaque bacteria in the etiology of dental caries
• Endodontic biofilms
• Types of Endodontic Biofilms
• Biofilms in Dental-Unit Waterlines
• Methods to eradicate biofilms
• Journal Review
• Conclusion
4. • The vast majority of micro organisms in nature
invariably grow and function as members of
metabolically integrated communities , or biofilms.
• Biofilm infections account for 65-80% of bacterial
infections affecting humans in the developing world.
• Given its importance, there has been a high level of
interest in the study of biofilm properties, not only in
medical microbiology, but also in different sectors of
industrial and environmental microbiology.
5. • HISTORY
1684- Antony van leewenhoek remarked on vast accumulation of
microorganisms in dental plaque.
1940- Claude zobel described many fundamental characters of
attatched microbial communities.
1977- Earliest use of term “biofilm” in swedish journal “vatten”.
1990- US national science foundation funded centre for biofilm
engineering at montana state university
Since that time, the field of biofilm research has exploded. Several
countries other than US also study biofilms namely Denmark,
england, germany, australia and singapore.
6. It is a mode of microbial growth where dynamic communities of
interacting sessile cells are irreversibly attached to a solid
substratum, as well as each other, and are embedded in a self made
matrix of extra cellular polymeric substances.
(Ingle’s Endodontics, 6th edn)
Defined as a community of microcolonies of microoorganisms in an
acqueos solution that is surrounded by a matrix made of glycocalyx,
which also attatches the bacterial cells to a solid
substratum.(grossman’s endodontic practice , 12th edn)
Biofilm
7. Basic criteria for biofilm formation
Microbial biofilm is considered a community and
the microorganisms living in the community must
possess :-
Ability to self organize ( autopoeisis)
Resist environmental perturbations (homeostasis)
Must be more effective in association than in isolation
(synergy)
Respond to environmental changes as a unit rather than
single individuals (communality)
8. Significance of biofilms
• It is one of the basic survival strategy employed by microorganisms
in all natural and industrial ecosystems in response to starvation.
• The sessile microbial cells in a biofilm state differ greatly from their
planktonic counterparts.
• Inside a biofilm, the bacterial cells exhibit altered phenotypic
properties and are protected from antimicrobial environmental
stresses, bacteriophage and phagocytic amoebe.
• Responsible for most of the chronic infections and almost all
recalcitrant infections in human beings, as bacteria in biofilm are
resistant to both antimicrobials and host defense mechanisms.
9.
10. Ultrastructure of biofilm
A fully developed biofilm is described as a heterogenous
arrangement of microbial cells on a solid surface.
Basic structural unit
• microcolonies or cell clusters formed by surface adherent
bacterial cells.
• Microcolonies are discrete units of densely packed
bacterial cells aggregates.
Structure of biofilm
12. • A fresh biofilm is made up of biopolymers such as
polysaccharides, proteins, nucleic acids and salts
Matrix material 85% vol.+ 15% microcolonies
• Glycocalyx matrix
Made up of EPS
Surrounds the microcolonies
Anchors the bacterial cells to the substrate.
Composition of biofilm
13. Importance of matrix
• Part of scaffold that determine biofilm structure.
• Biologically active-retains nutrients, water and
essential enzymes within the biofilm
• Can protect biofilm community from exogenous
threats.
• Participate in adherence to the surface.
14. Shape of biofilm
• Typically, a viable fully hydrated biofilm appears as
“tower” or “mushroom shaped structure”.
• The overall shape of biofilm structure is determined
by the shear forces generated by flushing of fluid
media.
15. The water filled channels
• Primitive circulatory system
• Intersect the structure of biofilm
• Establish connections between the
microbial colonies.
• Facilitates efficient exchange of
materials between bacterial cells and
bulk fluid.
• Coordinate functions in a biofilm
community.
16. Microcolonies
• Arise from surface colonization by planktonic
bacterial cells.
• During early stages, bacteria bind to many host
proteins and coaggregate with other bacteria.
• These interactions lead to changes in growth rate,
gene expression , and protein production.
17. Microorganisms can form biofilm on any surface that is bathed in
nutrient containing fluid.
Stages in the development of biofilm:
• Formation of the conditioning layer
• Adhesion of microbial cells to this layer
Development of biofilm
•pH
• temperature
• surface energy of substrate
• nutrient availability
•length of the time the bacteria is in
contact with the surface
• bacterial cell surface charge
•bacterial surface structure s
• surface hydrophobicity
18. • Adhesion -3 phases:-
• Transport of the microbe to substrate surface and its
attachment. Adherence factors includes :-
fimbriae, pili, flagella, EPS(glycocalyx).
• Microbial and substrate adherence phase to form bridge.
These bridges which are formed in a combination of
electrostatic attraction, covalent and hydrogen bonding
,dipole interaction and hydrophobic interaction.
• specific microbial –substrate adherence phase which
involves bonding of adhesin or ligand on the bacterial cell
surface
19. • Formation of bridges between the bacteria and conditioning layer
• Combination of electrostatic attractions, covalent and hydrogen
bonding and dipole interaction
Weak bond
Irreversible bond
A specific bacterial adhesion with a substrate
(polysaccharide adhesion)
20. Bacterial growth and biofilm expansion
• the monolayer of microbes attracts secondary colonizers
forming microcolonies, collectively forming the final structure
of biofilm.
• A mature biofilm will be metabolically active community of
microorganisms where individuals share duties and benefits.
21. Detachment of microcolonies
Two types of Detachment
Erosion
Sloughing
Erosion : continual detachment of single cell and small
portions of biofilm
Sloughing: rapid massive loss of biofilm
• Has important role in shaping the morphological
characteristics.
• “active dispersal mechanism” ( “Seeding dispersal”)
22.
23.
24. The bacterial cells in a biofilm will exhibit considerable variation in its
genetic and biochemical constitutions compared to its planktonic
counterparts.
25. • Coadhesion: process of recognition between a suspended cell
and a cell already attached to substrate
• Coaggregation: process where genetic distinct cells in
suspension recognize each other and clump together.
Microbial interactions in a biofilm
26. • Bacteria in a biofilm shows distinct capacity to survive tough
growth and environmental conditions.
• This unique capacity of bacteria in biofilm is due to following
features:
Biofilm structure protects the residing bacteria from
environmental threats.
Structure of biofilm permit trapping of nutrients and
metabolic co- operativity between resident cells of same
species and different species.
Biofilm structure display organized internal
compartmentalization
Bacterial cells in biofilm may communicate and
exchange genetic materials to acquire new traits.
Characteristics of biofilm
27. Protection of biofilm bacteria from environmental threats:
• protection and homeostasis
• capable of producing polysaccharides either as a cell surface
structure (capsules) or as extracellular excretions(EPS)
EPS
↓
covers biofilm communities
↓
Microniche
↓
Long term survival and functioning of bacterial communities
↓
Protects biofilm bacteria from environmental threat
(uv radiation, pH shift, osmotic shock and desiccation)
28. Nutrient trapping and establishment of metabolic
co-operativity in a biofilm
• Ability to concentrate trace elements and nutrients by physical
trapping or by electrostatic interaction.
• Outer fluid → water channels → interior of biofilm
↓
Nutrient availability to microbial communities
• For eg. Cells located near the center of a microcolony are more
likely to experience low oxygen tensions compared to cells located
near the surface. Moreover, due to juxtapostioning of different
cells, cross feeding and metabolic co-operativity between different
species of microorganisms are seen in a biofilm.
29. Organized internal compartmentalization
• Environmental niches that support the physiological
requirements of different species are available in a
biofilm.
• A mature biofilm displays gradients in the
distribution of nutrients, pH, oxygen, metabolic
products and signaling molecules within a biofilm.
• These gradients are influenced by types of nutrients
and physiological requirements of the resting
microorganisms.
• In a multispecies biofilm- both aerobic and anaerobic
microorganisms exists.
• Oxygen is consumed by aerobic and facultative
anaerobic bacteria and creates environment rich in
CO2 which supports the obligatory anaerobic species.
30. Bacterial cells residing in a biofilm communicate and
exchange genetic materials and acquire new traits
“Quorum Sensing”
• Communication through signaling molecules
• Mediated by low molecular wt molecules
• In sufficient concentration, can alter the
metabolic activity of neighboring cells
• Coordinate the function of resident bacterial
cells within a biofilm.
• Cross the cell membranes and trigger changes
• Helps in exchange of genetic materials
• Evolution of microbial communities with
different traits.
31. Resistance to microbes in biofilm to antimicrobials:
• Nature and physiological characterstics of biofilm provides
inherent resistance to antimicrobial agents –antibiotics,
disinfectants and germicides.
• Resistance amplify more than 1000 times for microbes in a
biofilm compared to planktonic cells.
• mechanisms responsible:-
Resistance associated with extracellular polymeric substance
Growth rate and nutrient availability
Adoption of resistant phenotype (metabolic alterations and
genetic alterations).
32. Resistance associated with EPS
• Inactivation of antimicrobials by EPS- observed
antimicrobial resistance in a biofilm.
• EPS forms the biofilm matrix- modify the response of
biofilm bacteria to antimicrobial treatment through its
actons as a diffusion barrier and reactor sink(neutralizer).
• highly charged and interwoven structure deters the
penetration of antimicrobials by ionic or electrostatic
interactions.
• constituents of biofilm matrix polymers may react
chemically and directly neutralize antimicrobials such as
iodine, chlorine and peroxides.
33. Resistance associated with growth rate and
nutrient availability
• Localized high cell density within a biofilm exposes
the deep lying cells to less nutrients and redox
potential.
• resistance to antimicrobials increase in thicker and
matured biofilms due to limited oxygen.
34. Resistance associated with adoption of
resistant phenotypes
• Long term survival of biofilm communities results in the
adoption or clonal expansions of a more resistant
phenotypes
• Nutrient limitation cause diminished growth, increased
expression of stress response gene, increased production
of shock proteins and activation of multi drug efflux
pump.
• Biofilm –enriched with Persistor cells-specialized survivor
cells which survive treatment procedures and proliferate
in the post-treatment phase.
35. • A community of organisms is formed rather than a haphazard collection of
bacteria.
• The bacteria in the biofilm are always metabolically active, causing
fluctuations in pH.
• These fluctuations may cause a loss of mineral from the tooth when the
pH is dropping or a gain of mineral when the pH is increasing (Manji et al.,
1991).
• The cumulative result - a net loss of mineral, leading to dissolution of the
dental hard tissues and the formation of a caries lesion.
• The biofilm tends to form and mature in certain locations on the tooth-
occlusal surface, approximal surface cervical to contact, gingival margin.
• these are the sites where caries lesions may become visible.
Caries and biofilms
36. After one week
• Clinically : no changes in the enamel.
• Ultrastructural level: signs of direct dissolution of the outer enamel
surface. This was seen as an enlargement of the intercrystalline spaces due
to partial dissolution of the individual crystal peripheries.
After two weeks
• Clinically "white spot" lesion
After three and four weeks :
• Clinically :white spot lesion :opaque with a matte surface.
• Ultrastructurally : complete dissolution of the thin perikymata
overlappings; marked dissolution corresponding to developmental
irregularities such as tomes' processes, pits, and focal holes; and
continued enlargement of the intercrystalline spaces.
Ultrastructural changes in enamel
related to the biofolm
37. Specific Plaque Hypothesis
• The "Specific Plaque Hypothesis" proposed that, out of the
diverse collection of organisms comprising the resident plaque
microflora, only a few species are actively involved in disease.
This proposal focused on controlling disease by targeting
preventive measures and treatment against a limited number
of organisms.
• "Non-Specific Plaque Hypothesis" considered that disease is
the outcome of the overall activity of the total plaque
microflora. In this way, a heterogeneous mixture of
microorganisms could play a role in disease.
Current hypotheses to explain the role of plaque
bacteria in the etiology of dental caries:
38. • More recently, an alternative hypothesis has been
proposed (the "Ecological Plaque Hypothesis") that
reconciles the key elements of the earlier two
hypotheses.
• Any environmental change that favours increasing
colonization by potential pathogenic bacteria would
cause disease.
39. Key features of this hypothesis
(a) the selection of "pathogenic" bacteria is directly coupled to
changes in the environment and
(b) diseases need not have a specific etiology; any species with
relevant traits can contribute to the disease process.
40. • A key element of the ecological plaque hypothesis is that
disease can be prevented not only by targeting the
putative pathogens directly, e.g. by antimicrobial or anti-
adhesive strategies, but also by interfering with the
selection pressures responsible for their enrichment.
• In dental caries, regular conditions of sugar/low pH or
reduction in saliva flow appear to be primary
mechanisms that disrupt microbial homeostasis.
41. Strategies that are consistent with the prevention of disease via the principles of the
ecological plaque hypothesis include the following:
(a) Inhibition of plaque acid production, e.g. by fluoride-containing products or other
metabolic inhibitors. Fluoride not only improves enamel chemistry but also inhibits
several key enzymes, especially those involved in glycolysis and in maintaining
intracellular pH.
• Fluoride can reduce the pH fall following sugar metabolism in plaque biofilms,
and in so doing, prevent the establishment of conditions that favor growth of acid-
tolerating cariogenic species.
(b) avoidance between main meals of foods and drinks containing fermentable sugars
and/or the consumption of foods/drinks that contain non-fermentable sugar
substitutes such as aspartame or polyols, thereby reducing repeated conditions of
low pH in plaque.
(c) the stimulation of saliva flow after main meals, e.g. by sugar-free gum. Saliva will
introduce components of the host response, increase buffering capacity, remove
fermentable substrates, promote re-mineralization, and more quickly return the
pH of plaque to resting levels.
43. • less diverse compared to oral microbiota.
• This transition in the microbial population is more
conspicuous with the progression of infections.
Progression of infection
↓ alters
Nutritional and environmental status within the root canal
↓
Root canal environment apparently becomes more anaerobic
and nutrient level will be depleted
↓
Tough ecological niche for the surviving microorganisms
Endodontic microbiota
44. • complete disinfection of the root canal system is very
difficult to achieve
root canal system complexities-deltas, isthumuses ,
lateral canals in apical portions .
Advantages of biofilm mode of microbial growth
45. Endodontic biofilms are of four types:
– intracanal biofilm
– extraradicular biofilm
– Periapical biofilm
– biomaterial centerd biofilms
46. • Microbial biofilms that are formed on root canal dentine of
an endodontically infected teeth.
• Exist as both loose microbial cells and biofilm structures,
• Made up of cocci, rods, and filamentous bacteria.
• It is monolayered or multilayered in structure.
Intracanal biofilms :
47. • Studies have revealed the ability of E. faecalis to resist
starvation and develop biofilms under different
environmental and nutrient conditions ( aerobic,
anaerobic, nutrient rich and nutrient deprived
conditions)
• A recent investigation has highlighted the ability of
E.faecalis to coaggregate with F.nucleatum.
• The coaggregation provides the ability of these
microorganisms to coexist in microbial community and
contribute to endodontic infection.
• Resistance to bactericidal action
• ability to form biofilm under tough environmental
conditions & nutritional conditions
48.
49. Stages in the development of E.faecalis
• Stage I: E.faecalis adhered and formed microcolonies
on dentin surface
• Stage II: E.faecalis induces bacterial mediated
dissolution of mineral fraction from dentin substrate-
increases calcium and phosphates ions and promote
calcifications of E.faecalis biofilms.(stage III)
50. • These biofilms are also known as “ root surface
biofilms”
• These biofilms are microbial films formed on the root
(cementum)surface adjacent to root apex of
endodontically infected teeth.
Extraradicular biofilms
51. • These types of biofilms are reported in teeth with
asymptomatic periapical periodontitis and teeth with
chronic apical abscess associated with sinus tracts.
• They consist of cocci and rods and filamentous
species, with cocci attached to tooth substrate.
• Mostly multi-species in nature, contained varying
degrees of extracellular matrix materials(Tronstad et
al)
52. Periapical microbial biofilms
• These are isolated biofilms found in periapical region of an
endodontically infected teeth.
• The microbiota in majority of teeth associated with apical
periodontitis is restricted to root canal as most of the
microbial species that infect the root canal are opportunistic
pathogens that don’t have the ability to survive the host
defense mechanisms in periapical tissues.
• Rarely, microbial species or even strains within species may
possess strategies to survive and thus infect periapical tissues.
53.
54. • The members of genus Actinomyces and
P.propionicum have been demonstrated in
asymptomatic periapical lesions refractory to
endodontic treatment.
• These microorganisms have the ability to overcome
host defense mechanisms, thrived in inflamed
periapical tissue and subsequently induce a
periapical infection
55. Biomaterial centered biofilm
• It is caused when microorganisms adheres to an
artificial biomaterial surface and forms biofilms
structures.
• Presence of biomaterials in close proximity to host
immune systems can increase the susceptibility to
Biomaterial centered infections
• Biomaterial centered infection is one of the major
complications associated with prosthesis and or
implant related infections
56. • Furthermore, biofilms are extremely resistant to host
defense mechanisms and antibiotic treatment, BCI
are rarely resolved and often the only solution to an
infected biomaterial is the surgical removal.
• species like Staphylococcus aureus, Enterococcus
fecalis, streptococci and Pseudomonas aeruginosa
and fungi ( Candida albicans) are most commonly
isolated species.
57. • Biomaterial centered biofilms would form on root
canal obturating materials and can be intraradicular
or extraradicular.
Biofilm on extruded gutta percha
58. • presence of biofilms in dental-unit waterlines -known
since 1963.
• discovery that biofilms contribute to the microbial
contamination of dentalunit waterlines has made the
need for cleansing systems apparent, to minimize the
potential danger of infection and cross contamination.
• In dental-unit waterlines, biofilms measured to be
30-to-50 micrometers thick.
BIOFILMS IN DENTAL- UNIT WATER LINES
59. • Microbial populations found in dental-unit waterlines - most
common opportunistic pathogens linked to hospital-related
waterborne infections; e.g., Pseudomonas, Legionella, and
non-tuberculous Mycobacterium.
• -Predominant early colonizers - Pseudomonas spp.,
Pasteurella, Moraxella, Ochrobactrum, with Aeromonas spp.,
Flavobacterium, and Acinetobacter spp. being observed later.
Many of these organisms are opportunistic pathogens.
60. • American Dental Association and the Centers for Disease
Control and Prevention endorse flushing water lines for
several minutes prior to the first patient visit and for 20 to 30
seconds between patients.
• Flushing between patients will most likely reduce levels of oral
flora, which do not typically colonize upstream tubing.
• quality of dental-unit water is of considerable importance
since patients and dental staff are regularly exposed to water
and aerosols generated from the dental-unit.
61. • Average living microbial counts in water from handpieces and
air-water syringes are in the range of 300,000 to 400,000 CFU
per ml .
• Most plastic dental tubing has an inside diameter of 1/16-to-
1/8 inch and thus has a very large surface area to volume
ratio.
• hydrophobic surface of waterline plastics promotes the
attachment and colonization of biofilm organisms.
• The layered structure of biofilms (limiting diffusion) combined
with the low flow conditions renders these microbial colonies
intrinsically resistant to many biocides and cleansing schemes
62. • Schemes to reduce microbial counts in dental treatment
water fall into four broad categories:
• (i) use of water systems that are independent of public
systems, including those designed to deliver sterile water
• (ii) chemical treatments that are provided either
continuously or intermittently;
• (iii) filters placed inline just before the point of use (i.e.
handpiece, three-way syringe, ultrasonic scaler);
• (iv) devices to create turbulent and/or high energy flow
conditions to cleanse fine tubing.
64. Methods to eradicate biofilms
• Sodium hypochlorite -effective irrigant to destroy
all forms of Enterococcus faecalis including its biofilm
forms.
• Chlorhexidine 2% gel or liquid form- effective to
eliminate Enterococcus faecalis from the superficial
layers of dentinal tubules up to 100 micrometer.
• New techniques- ultrasonic irrigation, ozone, plasma
dental probe, photoactivated disinfection with low-
energy laser.
65.
66. • 1-minute use of ultrasonically activated irrigation,
followed by root canal cleaning and shaping -shown
to improve canal and isthmus cleanliness in terms of
necrotic debris/biofilm removal.
• High concentrated gaseous and aqueous ozone is
strain, dose and time dependently effective against
the tested microorganisms in suspension and biofilm
test model.
67. Plasma dental probe
• effective for tooth disinfection.
• SEM shows complete destruction of endodontic biofilms for a
depth of 1 mm inside a root canal after plasma treatment for 5 min.
Er:YAG laser
• produced excellent results due to its capacity for ablating hard
tissue with very less thermal effects.
• considered to be effective tool for the removal of apical biofilm.
68. Photodynamic therapy/ Light Activated Therapy
• latest method used to destruct endodontic biofilm.
• involves the killing of microorganisms when a photo
sensitizer selectively accumulated in the target is
activated by a visible light of appropriate wavelength.
PAD is a unique combination of a photosensitizer solution
and low-power laser light. The photosensitizer, which is
mostly colored, adheres to or gets absorbed by microbial
cells. The low-power laser will destruct the target area
and inactivate the microbial invaders
69. CONCLUSION
Biofilm biology has become an expanding field of research in
human, industrial and environmental ecosystems. The
knowledge accumulated suggests that organisms growing in
biofilms develop properties different to those dwelling in the
planktonic state.
When assessing treatment options, an appreciation of the
ecology of the oral cavity will enable the enlightened clinician
to take a more holistic approach and consider the nutrition,
physiology, host defenses, and general well-being of the
patient, as these will affect the balance and activity of the
resident oral microflora.
Identification of such critical control points can lead to the
selection of appropriate preventive strategies that are
tailored to the needs of individual patients.
70. Screening, characterisation , in vitro biofilm
formation and antifungal resistance of candida
species
• Vinodini, latha et al :King saudi university journal of
dental sciences, july 2013
Aim:-This study determined the presence of Candida spp. in dental plaques of
both males and females. Pooled samples of dental plaque were collected
from 25 males and 55 females aged between 25 and 50 years.
Methods:-Colony growth was verified and 30 Candida isolates were chosen
for the screening. The identification of biofilm forming Candida was
confirmed by performing several screening techniques (Microtiter plate
method, Test tube method.
71. • The biofilm formation ofCandida spp. on catheter was evaluated using
scanning electron microscopic analysis. The extra cellular polysaccharide
(EPS) quantity was measured with the effect of different carbon sources,
adherence time and biofilm forming time. The above isolates were
screened for antifungal resistance against six clinically important
antifungal agents such as Amphotericin B, Ketaconazole, Fluconazole,
Itraconazole, Nystatin and Clotrimazole (10 μg/ml)
• Results:-The biofilm forming isolates were significantly resistant to the
antifungal drugs in comparison with non-biofilm forming Candida isolates.
The present study reveals the presence of Candida biofilm on human
dental surface and indicates the magnitude of antibiotic resistance.
72. Difference in initial biofilm accumulation during
night and day, Trene dige, sebastian et
al,Scandinavian dental journal..dec 2012
• Objective. The study of initial microbial colonization on dental surfaces is a
field of intensive research because of the aetiological role of biofilms in
oral diseases. Most previous studies of de novo accumulation and
composition of dental biofilms in vivo do not differentiate between
biofilms formed during day and night. This study hypothesized that there is
a diurnal variation in the rate of accumulation of bacteria on solid surfaces
in the oral cavity.
• Materials and methods. In situ biofilm from healthy individuals was
collected for 12 h during day and night, respectively, subjected to
fluorescent in situ hybridization and visualized using confocal laser
scanning microscopy
73. • Results. Analysis of the biofilms using stereological methods and digital
image analysis revealed a consistent statistically significant difference
between both the total number of bacteria and the biovolume with the
highest accumulation of bacteria during daytime .
• Conclusion. The data provide firm evidence that initial biofilm formation
decreases during the night, which may reflect differences in the availability
of salivary nutrients. This finding is of significant importance when
studying population dynamics during experimental dental biofilm
formation
74. Anti-biofilm dentin primer with quaternary
ammonium and silver nanoparticles
• Cheng L, Zhang K, Melo MA, j Dental research june
2012
• The objectives of this study were to develop novel antibacterial dentin
primers containing quaternary ammonium dimethacrylate (QADM) and
nanoparticles of silver (NAg), and to investigate the effects on dentin bond
strength and dental plaque microcosm biofilms for the first time.
• Methods:- Scotchbond Multi-Purpose ("SBMP") bonding agent was used.
QADM and NAg were incorporated into SBMP primer, yielding 4 primers:
SBMP primer (control), control + 10% QADM (mass), control + 0.05% NAg,
and control + 10% QADM + 0.05% NAg. Human saliva was collected to
grow microcosm biofilms.
75. • Results:-QADM-NAg-containing primer increased the bacteria inhibition
zone by 9-fold, compared with control primer (p < 0.05). QADM-NAg-
containing primer reduced lactic acid production and colony-forming units
of total micro-organisms, total streptococci, and mutans streptococci by an
order of magnitude. In conclusion, novel QADM-NAg-containing primers
were strongly antibacterial without compromising dentin bond strength,
and hence are promising to inhibit biofilms and secondary caries
76. Antimicrobial efficacy of non-thermal plasma in comparison to
chlorhexidine against dental biofilms on titanium discs in vitro
• Koban I, Holtfreter B, Hübner NO, archives of oral
biology ,Aug 2012
• AIM:
In this study, the effect of three different plasma devices on the reduction
of Streptococcus mutans (S. mutans) and multispecies human saliva
biofilms was evaluated.
• MATERIAL AND METHODS:
• assessed the efficacy of three different non-thermal atmospheric pressure
plasma devices against biofilms of S. mutans and saliva multispecies grown
on titanium discs in vitro in comparison with a chlorhexidine digluconate
(CHX) rinse. Efficacy of plasma treatment was determined by the number
of colony forming units (CFU) and by scanning electron microscopy. The
results were reported as reduction of CFU (CFU(untreated) -CFU(treated) ).
77. • The application of plasma was much more effective than CHX against
biofilms. The maximum reduction of CHX was 3.36 for S. mutans biofilm
and 1.50 for saliva biofilm, whereas the colony forming units (CFU)
reduction of the volume dielectric barrier discharge argon plasma was
5.38 for S. mutans biofilm and 5.67 for saliva biofilm.
• CONCLUSIONS:
• Treatment of single- and multispecies dental biofilms on titanium discs
with non-thermal atmospheric pressure plasma was more efficient than
CHX application in vitro.
78. REFERENCES
• INGLE’S ENDODONTICS-6TH EDITION
• COHEN’S PATHWAYS OF THE PULP-10TH EDITION
• GROSSMAN’s Endodontic practice, 12TH EDITION
• Biofilm in endodontics- Review by Usha H.L,
Anjali Kaiwar, Deepak Mehta.
Editor's Notes
First step is the adsorption of inorganic and organic molecules to solid surface creating
The structural feature of biofilm that has the highest impact in chronic bacterial infection is the tendency of to detach from the biofilm community
Detachment has been understood to play an important role in shaping the morphological characteristics.
It is also an “active dispersal mechanism” or “Seeding dispersal” where detached cells form resistance traits which is the source of persistent infections.
Complex architecture of biofilm-allow for metabolic co-operation..(w.recta produce hemin-p.gingivalis)
Biofilm provides a setting for communication
The biofilm tends to form and mature in certain locations on the tooth, notably the occlusal surface, especially during eruption, the approximal surface cervical to the contact point, and along the gingival margin. These areas are relatively protected from mechanical wear by tongue, cheeks, abrasive food, and toothbrushing.
Thus, the surface participates in the enamel reaction from the very beginning of lesion formation by direct dissolution of the outermost microsurface and enlargement of intercrystalline diffusion pathways.
This direct surface erosion is most likely partly responsible for the matte surface of the active lesion.
In some respects, the arguments about the relative merits of these hypotheses may be about semantics, since plaque-mediated diseases are essentially mixed culture (polymicrobial) infections, but in which only a limited (perhaps specific!) number of species are able to predominate.
microorganisms are found to persist in the root canal system complexities such as apical portions, deltas, isthmuses and lateral canals etc.
These anatomical complexities shelter the adhering bacteria in a biofilm from cleaning and shaping procedures