ORAL MICROBIAL FLORA
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

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contents
Introduction and history
Morphology of bacteria/viruses/fungi
General concepts of pathology
Host-parasite interac...
The principal microorganisms of the mouth
Dental plaque
Dental caries and periodontal disease
Bacterial/ viral/fungal infe...
The Normal Flora
Our bodies are like mobile warmblooded coral reefs, rich in
microbial biodiversity and home to
vast numbe...
Disease can come about in several overlapping ways
1. Some bacteria are entirely adapted to the pathogenic way of life in
...
What are bacteria?

Bacteria are single cell organisms that are found living throughout our
world. Bacteria eat everything...
Typical Bacteria Structure

Flagellalocomotion, flagellin(protein
)
Fimbriae- helps in
adhesion
Calpsule-mucoid
envelope, ...
Types of Bacteria

Microbiologists classify bacteria according to their

shape: spherical, rod-shaped, and spiral-shaped.
...
Bacteria may be further classified according to
whether they require oxygen (aerobic) or no
oxygen (anaerobic)

Bacillus a...
Morphology of viruses
Viruses are obligate intracellular parasites
Do not fall strictly into the category of unicellular
m...
Morphology of fungi
Unicellular with oval/spherical cells 2-5 micro mt
Produce a pseudomycelial form comprising of a netwo...
Normal Microbiota
Animals are generally free from microbes in utero.
After birth, microbial populations rapidly establish
...
Most complex and diverse…….
Oral cavity provides ideal enviornment…

Why care about the normal flora?
colonization resista...
Why care about the normal flora?

commensal bacteria may cause disease at their site of
carriage or nearby, e.g.
Streptoco...
Interaction Between the Normal Microbiota
and the Host
SYMBIOSIS: “Living together”.
1. Commensalism: One organism benefit...
Opportunistic Pathogens
The nature of symbiotic relationships can change.
Opportunistic Pathogens: Organisms that normally...
Etiology of Infectious Diseases
Diseases can be caused by many factors: infection,
genetics, degeneration, and others.
Koc...
Koch’s Postulates for Infectious Diseases

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Exceptions to Koch’s Postulates
Koch’s principles do not apply to all diseases.
1. Some microbes cannot be cultured in art...
Transmission of Disease
I. Contact Transmission: Spread by direct contact,
indirect contact, or droplet transmission.
A. D...
Transmission of Disease (Continued)
II. Vehicle Transmission: Transmission of disease via
medium such as water, food, air,...
CHAIN OF INFECTION
All links must be connected for infection to take place

Pathogen

(sufficient virulence
& adequate num...
Nosocomial (Hospital Acquired) Infections
“Nosocomial” Greek word for hospital.
Infections acquired at a health care facil...
Important Nosocomial Pathogens
Normal microbiota: Many are opportunistic pathogens
Antibiotic resistance: Very high due to...
Control of Nosocomial Infections
Aseptic techniques to avoid contamination
Careful handling and disposal of contaminated m...
Development of Disease
1. Incubation Period: Time between initial infection and
appearance of signs and symptoms
2. Prodro...
Immunity in the oral cavity
Non specific immunity
-intact mucosal barrier
-dental arches position
-saliva
-lysozyme
-perox...
Development of the oral flora
Birth – sterile…..
- strep.salivarius, Nesseria, veillonella
- occasionally C.albicans…..

I...
Development of oral flora contd
Adolescence
increase in no. of organisms occurs when permanent
teeth erupt
They have deep ...
Development of oral flora contd
Adulthood
complexity is its characteristic
-Varying amounts of dp,chronic pdl disease, gov...
Factors affecting the development of the oral
flora
Be introduced
Be retained
Be able to multiply in the conditions presen...
Factors affecting the development of the oral
flora contd..
Introduction
- although from birth a wide variety of microorga...
Multiplication
Factors governing are
- availability of substrates
* increased carbohydrate in the diet, increases the no. ...
Multiplication contd
Microbial interactions
Some of the interactions are nutritional such as
provision of PABA by strep.sa...
The normal microbial flora of different sites of the mouth
Lips
staph.albus and skin micro-cocci predominate with large no...
The normal microbial flora of different sites of the mouth contd
Gingival crevices
-most numerous of any site in the mouth...
Dentures and other intra oral appliances

Any appliance worn for considerable period, become colonized
with microorganisms...
The principal microorganisms of the mouth
Cocci
Gr+ve
strep.sanguis
strep.mutans
strep.mitior
strep.salivarius
strep.mille...
The principal microorganisms of the mouth
contd
Anaerobic bacteria- spirochaetes
Yeasts- C.albicans, tropicalis, krusei
My...
Dental plaque
Dental plaque is defined as soft deposits that form the biofilm
adhering to the tooth surface or other hard ...
Microbial interactions in DP
Benificial or detrimental
Strep.mutans, sanguis & lactobacilli lowers the
ph by the fermentat...
calculus
Produced by calcification of supra & subgingival dental
plaque
Hardness varies as the deposition of calcium phosp...
Control of dental plaque
Diet
Physical removal
Ultrasonic scaling devices
Antiseptics
Antibiotics

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Dental Caries
Odontopathic
Bacteria

Mutans group
of Streptococci
Initiator of Caries

Lactobacillus
(acid-loving bacteria...
CARIOGENIC DENTAL PLAQUE
Bacteria produce a strong acid - Lactic Acid
Bacteria produce surface molecules which seal the
ac...
LACTOBACILLUS
Acidophilic (acid-loving) environments
(Inside Deep Carious Lesions)

{

pH =

5.3
4.5

pH = 4.5
3.7

{

LAC...
Dental caries
Microbiological aspect of caries prevention
diet
plaque control
immunisation against dental caries
based on ...
Periodontal disease
Acute
ANUG
periodontal abscess
Chronic
gingivitis
periodontitis
juvenile periodontitis

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Periodontal disease contd
ANUG
Characterized by the destruction of interdental papillae and often
gingival margin
Isolated...
Periodontal disease contd
Gingivitis
Inflammation of gingivae appears to be caused by bacteria and
their products in denta...
Periodontal disease contd
chronic periodontitis
Gingivitis if not controlled leads to periodontitis
Attachment of junction...
Juvenile periodontitis

Some young patients develop a degree of pdl destruction well in advance of
that expected for their...
Bacterial infections of oral cavity

Syphilis
Actinomycoses
Tuberculosis
Diphteria
Scarlet fever
Leprosy
Tetanus

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Candidiasis (oral thrush)
Caused by candida albicans
Common inhabitant of oral cavity
Most opportunistic infection in worl...
Types of Candidiasis
Pseudomembranous
candidiasis Thrush
Hyperplastic candidiasis
Atrophic candidiasis

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Viral infections of oral soft tissues
HSV-1 and/or HSV-2
Primary Infection
Secondary Infection
Varicella zoster virus (HHV...
Herpesvirus Infection
Secondary Infection
Reactivation of latent virus
Not associated with
systemic symptoms
Small vesicle...
Herpangina
NOT caused by Herpesvirus
Coxsackie A virus
Children < 10 years of age
Common in summer and fall
Often subclini...
Why Is Infection Control Important
in Dentistry?
Both patients and dental health care personnel (DHCP)
can be exposed to p...
Modes of Transmission
Direct contact with blood or body fluids
Indirect contact with a contaminated
instrument or surface
...
Standard Precautions
Apply to all patients
•Elements of Standard Precautions
Handwashing
Use of gloves, masks, eye
protect...
Personal Protective Equipment
,

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Sterilization and Disinfection
of Patient Care Items

Critical
Instruments

Penetrate mucous membranes or contact bone, th...
Noncritical Instruments and Devices
Contact intact skin
Clean and disinfect using a low to intermediate level disinfectant...
Preprocedural Mouth Rinses
Antimicrobial mouth rinses prior to a dental
procedure

Reduce number of microorganisms in
aer...
Extracted Teeth
Considered regulated medical waste
Do not incinerate extracted teeth containing amalgam
Clean and disinfec...
Automated Cleaning
Ultrasonic cleaner
Instrument washer
Washer-disinfector

Manual Cleaning
Soak until ready to clean
Wear...
Heat-Based Sterilization

Steam under pressure (autoclaving)
Dry heat
Unsaturated chemical vapor

Liquid Chemical
Sterilan...
Disinfectants
Disinfectants are chemicals that destroy or inactivate most
species of pathogenic (disease-causing) microorg...
Environmental Surfaces
May become contaminated
Not directly involved in infectious disease transmission
Do not require as ...
Clinical Contact Surfaces

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Housekeeping Surfaces

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Cleaning Clinical Contact Surfaces
Risk of transmitting infections greater than for
housekeeping surfaces
Surface barriers...
Infection control in dental laboratory
Potential for disease transmission in the dental lab
is well documented
Potential p...
MASK/PROTECTIVE
EYEWEAR/CLOTHING
Must be used when there is potential for
splashes, spray, spatter, or aerosols
Examples: ...
IMPRESSIONS
Many studies have been performed to evaluate
effects of various disinfectants on different types
of impression...
IMPRESSIONS
Many variables can affect impression materials
Composition and concentration of disinfectants
Exposure time an...
DISINFECTING IMPRESSIONS
Methods
Spraying, immersing

Exposure time should be that recommended by the
manufacturer of disi...
DISINFECTING IMPRESSIONS
Polyether materials cannot be immersed in disinfectants due to
potential for absorption and disto...
DENTAL CASTS

Very difficult to disinfect
It Is preferable to disinfect impression
If casts must be disinfected:
Place cas...
ORALLY SOILED PROSTHESES
Scrub with brush and antimicrobial soap to
remove debris and contamination
Can be accomplished in...
LATHE
Ways to reduce risk of injury from aerosols, spatter, and macroscopic particles
Use protective eyewear
Ensure plexig...
IMPRESSION TRAYS
Precleaning removes bioburden and any
adherent impression material
Ultrasonic cleaning can aid in removin...
DISINFECTION
Prosthodontic items contaminated by handling should be disinfected (by spray
or immersion technique based on ...
PERSONAL HYGIENE
Refrain from the following activities while in the
lab where there is potential for occupational
exposure...
conclusion
Very few microbes are
always pathogenic

Many microbes are
potentially pathogenic

Most microbes are
never path...
References

Text book of microbiology; 5th edition: ananthnarayan
Medical bacteriology; key and key
Oral microbiology & im...
Thank you
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Oral microbial flora /certified fixed orthodontic courses by Indian dental academy

  1. 1. ORAL MICROBIAL FLORA INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. contents Introduction and history Morphology of bacteria/viruses/fungi General concepts of pathology Host-parasite interaction Immunity in the oral cavity Development of oral flora Factors affecting development of oral flora The normal microbial flora of different sites of the mouth www.indiandentalacademy.com
  3. 3. The principal microorganisms of the mouth Dental plaque Dental caries and periodontal disease Bacterial/ viral/fungal infection of oral soft tissues Prosthodontic considerations Infection control in dental laboratory and dental clinics Conclusion References www.indiandentalacademy.com
  4. 4. The Normal Flora Our bodies are like mobile warmblooded coral reefs, rich in microbial biodiversity and home to vast numbers of bacterial cells there are more bacterial cells (1014) associated with the human body than there are human ones (only 1013)! composition of normal flora varies from individual to individual some bacterial species carried only transiently most fairly permanent www.indiandentalacademy.com
  5. 5. Disease can come about in several overlapping ways 1. Some bacteria are entirely adapted to the pathogenic way of life in humans. They are never part of the normal flora but may cause subclinical infection, e.g. M . tuberculosis 2. Some bacteria which are part of the normal flora acquire extra virulence factors making them pathogenic, e.g. E. coli 3. Some bacteria which are part of the normal flora can cause disease if they gain access to deep tissues by trauma, surgery, lines, e.g. S. epidermidis 4. In immunocompromised patients many free-living bacteria and components of the normal flora can cause disease, especially if introduced into deep tissues, e.g. Acinetobacter www.indiandentalacademy.com
  6. 6. What are bacteria? Bacteria are single cell organisms that are found living throughout our world. Bacteria eat everything from sugar, starch, sulfur and iron. There's even a species of bacteria—Deinococcus radiodurans—that can withstand blasts of radiation 1,000 times greater than a human being could survive! www.indiandentalacademy.com
  7. 7. Typical Bacteria Structure Flagellalocomotion, flagellin(protein ) Fimbriae- helps in adhesion Calpsule-mucoid envelope, resists phagocytosis, forms hapten Cellwall-outermost layer Cytoplasmic membrane cytoplasm www.indiandentalacademy.com
  8. 8. Types of Bacteria Microbiologists classify bacteria according to their shape: spherical, rod-shaped, and spiral-shaped. Coccus Bacillus www.indiandentalacademy.com Spirillum
  9. 9. Bacteria may be further classified according to whether they require oxygen (aerobic) or no oxygen (anaerobic) Bacillus anthracis Peptostreptococcus Aerobic bacteria Anaerobic bacteria www.indiandentalacademy.com
  10. 10. Morphology of viruses Viruses are obligate intracellular parasites Do not fall strictly into the category of unicellular microorganisms as they do not possess a cellular organisation They contain only one type of nucleic acid either DNA/RNA but never both Much smaller than bacteria Largest abt 300nm, poxviruses Smallest abt 20nm,parvoviruses Nucleicacid core surrounded by a protein coat, the capsid Capsid functions to introduce viral genome into host cells by adsorbing readily to cell surfaces DNA VIRUSES- poxvirus,herpes virus, adeno virus, papova virus RNA VIRUSES- picorna virus, orthomyxo virus, paramyxo virus, retro virus, toga virus www.indiandentalacademy.com
  11. 11. Morphology of fungi Unicellular with oval/spherical cells 2-5 micro mt Produce a pseudomycelial form comprising of a network of interlacing filaments www.indiandentalacademy.com
  12. 12. Normal Microbiota Animals are generally free from microbes in utero. After birth, microbial populations rapidly establish themselves in the newborn’s body. Feeding and breathing introduce many more microbes.   E. coli and other bacteria colonize large intestine. Candida albicans colonizes mucous membranes. Normal Microbiota or Flora: Microorganisms that remain throughout an individual’s life. Transient Microbiota: Microorganisms that are present for a certain time period and then disappear. Cells in human body: 1 x 1013 Microbes associated with human body: 1 x 1014 There are ~10 microorganisms/human body cell. www.indiandentalacademy.com
  13. 13. Most complex and diverse……. Oral cavity provides ideal enviornment… Why care about the normal flora? colonization resistance: competition for space and nutrients with pathogens release of bacteriocins and colicins (antibacterial substances) to prevent pathogen growth vitamin K production in gut continued antigenic stimulation from commensals cross-reacting protective immunity against pathogens commensal neisseriaceae and Neisseria meningitidis www.indiandentalacademy.com
  14. 14. Why care about the normal flora? commensal bacteria may cause disease at their site of carriage or nearby, e.g. Streptococcus mutans (mouth)  causes dental caries Streptococcus pneumoniae (upper airways)  causes otitis media, sinusitis Some members of the normal flora can become pathogenic if they acquire additional virulence factors (e.g. E. coli) or are introduced into normally sterile sites (e. g. Staphylococcus aureus) www.indiandentalacademy.com
  15. 15. Interaction Between the Normal Microbiota and the Host SYMBIOSIS: “Living together”. 1. Commensalism: One organism benefits, the other is not affected (+/0).  Many microbes live off secretions and dead cells and do not benefit or harm host. 2. Mutualism: Both organisms benefit from living together (+/+).  E. coli synthesizes vitamin K and some B vitamins. 3. Parasitism: One organism benefits, the other is harmed (+/-).  Most disease causing bacteria. www.indiandentalacademy.com
  16. 16. Opportunistic Pathogens The nature of symbiotic relationships can change. Opportunistic Pathogens: Organisms that normally do not cause disease in their natural habitat in a healthy person. They may cause disease if the host is weakened or if they enter a different part of the body. Pneumocystis carinii pneumonia in AIDS patients. Tooth decay and gum disease caused by mouth flora. Neisseria meningitidis is usually harmless in respiratory tract, but can cause meningitis. www.indiandentalacademy.com
  17. 17. Etiology of Infectious Diseases Diseases can be caused by many factors: infection, genetics, degeneration, and others. Koch’s Postulates Developed by Robert Koch in 1877 to establish cause of infectious diseases: anthrax and TB. 1. Same pathogen must be present in every case of the disease. 2. Pathogen must be isolated from diseased host and grown in pure culture. 3. Pathogen from pure culture must cause disease when inoculated in healthy, susceptible laboratory animal. 4. Pathogen must be isolated from inoculated animal and shown to be the original organism. www.indiandentalacademy.com
  18. 18. Koch’s Postulates for Infectious Diseases www.indiandentalacademy.com
  19. 19. Exceptions to Koch’s Postulates Koch’s principles do not apply to all diseases. 1. Some microbes cannot be cultured in artificial media.  Treponema pallidum (syphillis)  Mycobacterium leprae (leprosy)  Ricketsias, chlamydias, and viruses only multiply within cells. 2. One disease may involve several different pathogens.  Diarrhea  Pneumonia  Meningitis  Nephritis 3. Some pathogens may cause several different diseases.  Streptococcus pyogenes: Scarlet fever, sore throat, skin infections, bone infections, etc.. www.indiandentalacademy.com
  20. 20. Transmission of Disease I. Contact Transmission: Spread by direct contact, indirect contact, or droplet transmission. A. Direct Contact Transmission: Person-to-person transmission. No intermediate object is involved. Examples: Touching, kissing, sexual intercourse. B. Indirect Contact Transmission: Agent is transferred via a nonliving object (fomite). Examples: Towels, eating utensils, thermometers, stethoscopes, bedding, clothes, money, and syringes. C. Droplet Transmission: Microbes are spread in mucus droplets that travel short distances (less than 1 meter). Examples: Sneezing, coughing, talking, and laughing. www.indiandentalacademy.com
  21. 21. Transmission of Disease (Continued) II. Vehicle Transmission: Transmission of disease via medium such as water, food, air, blood, body fluids, and intravenous fluids.   Waterborne Transmission: Usually caused by water contaminated with sewage. Airborne Transmission: Spread of agents by droplets in dust that travel more than 1 m to host. III. Vectors: Animals that carry disease from one host to another. Arthropods (insects) are most important animal vectors.   Mechanical Transmission: Passive transport of pathogens on insect’s body. Biological Transmission: Pathogen spends part of its life cycle in the vector. www.indiandentalacademy.com
  22. 22. CHAIN OF INFECTION All links must be connected for infection to take place Pathogen (sufficient virulence & adequate numbers) Susceptible Host (allows pathogen to survive & multiply) (i.e., one that is not immune) Entry Source Mode (of transmission from source to host) (portal that the pathogen can enter thewww.indiandentalacademy.com host)
  23. 23. Nosocomial (Hospital Acquired) Infections “Nosocomial” Greek word for hospital. Infections acquired at a health care facility. According to Center for Disease Control (CDC), 5-15% of all hospital patients acquire N.I.s. Predisposing Factors:    Wide variety of microbes in hospital environment Weakened or immunocompromised patients Chain of transmission: Mainly through direct or indirect contact. • • • • From health care workers to patient From patient to patient Fomites: Catheters, needles, dressings, beds, wheelchairs Airborne transmission www.indiandentalacademy.com
  24. 24. Important Nosocomial Pathogens Normal microbiota: Many are opportunistic pathogens Antibiotic resistance: Very high due to the use of antimicrobials in health care facilities. Principle microorganisms: Used to be gram-positive microbes. Today most are gram-negative bacteria.      Enterobacteria: Over 40% of all infections. E. coli, Klebsiella spp., Proteus spp., Enterobacter spp., and Serratia marcescens. Staphylococcus aureus (11%) Fungi: (10%) C. albicans and others Enterococcus (10%) Pseudomonas aeruginosa (9%) www.indiandentalacademy.com
  25. 25. Control of Nosocomial Infections Aseptic techniques to avoid contamination Careful handling and disposal of contaminated material Frequent and adequate hand washing Proper infection control training of staff Isolation wards and rooms Avoid unnecessary antibiotic prescriptions Avoid unnecessary invasive procedures Regular disinfection of respirators and humidifiers and maintenance of autoclaves Use disposable and/or sterile supplies Infection control committee www.indiandentalacademy.com
  26. 26. Development of Disease 1. Incubation Period: Time between initial infection and appearance of signs and symptoms 2. Prodromal Period: Early, mild symptoms of disease. 3. Illness Period: Disease is most acute. Overt signs and symptoms. Patient immune system actively fights off infection. If not successful may die at this stage. 4. Decline Period: Signs and symptoms subside. Patient is vulnerable to secondary infections. 5. Convalescence Period: Recovery. Body returns to predisease state. www.indiandentalacademy.com
  27. 27. Immunity in the oral cavity Non specific immunity -intact mucosal barrier -dental arches position -saliva -lysozyme -peroxidase -lactoferrin Specific immune response -tissues -immunoglobulins and other soluble mediators www.indiandentalacademy.com
  28. 28. Development of the oral flora Birth – sterile….. - strep.salivarius, Nesseria, veillonella - occasionally C.albicans….. Infancy & early childhood eruption of deciduous teeth appearance of strep. Sanguis & mutans Increasing no. of teeth and changes in diet….. Few anaerobic become established……. www.indiandentalacademy.com
  29. 29. Development of oral flora contd Adolescence increase in no. of organisms occurs when permanent teeth erupt They have deep fissures, interproximal surfaces are larger, gingival crevice is deeper---- increase in anaerobic organisms Bacteroides, leptotrichia, fusobacterium, spirochaetes are found regularly Lesions of dental caries……….. www.indiandentalacademy.com
  30. 30. Development of oral flora contd Adulthood complexity is its characteristic -Varying amounts of dp,chronic pdl disease, govern the no. and type of organisms… carious lesions, unsatisfactory restorations provides environments for accumalations of bacteria -Increase in bacteriodes and spirochaetes -As teeth are lost…….. -Edentulous pts. harbour few spirochaetes or bacteroides. Carriage of yeasts increases -Dentures provide a protected environment in which yeasts multiply… www.indiandentalacademy.com
  31. 31. Factors affecting the development of the oral flora Be introduced Be retained Be able to multiply in the conditions present in the mouth www.indiandentalacademy.com
  32. 32. Factors affecting the development of the oral flora contd.. Introduction - although from birth a wide variety of microorganisms are introduced into mouth, only certain species are able to become established Retention - adherence eg.strep.salivarius - protected sites Sticky matrix of dental plaque and gingival crevices bact.melaninogenicus and spirochates www.indiandentalacademy.com
  33. 33. Multiplication Factors governing are - availability of substrates * increased carbohydrate in the diet, increases the no. of oral bacteria - ph * bact. Melaninogenicus, veillonella are intolerent of ph below 5.5 * lactobacillus and C.albicans can tolerate very low ph values - oxidation/reduction of the surroundings * anaerobic organisms such as bacteroides, fusobacterium, spirochaetes, actinomyces only multiply in reduced surroundings. * gingival crevice and deeper layer of dental plaque are the areas with low oxidation/reduction potential www.indiandentalacademy.com
  34. 34. Multiplication contd Microbial interactions Some of the interactions are nutritional such as provision of PABA by strep.sanguis for strep.mutans in reduced conditions. The provision of vitamin k by several microorganisms for bact.melaninogenicus Some of the interactions are detrimental rather than beneficial to a second species eg. Production of H2 O2 by strep.sanguis inhibit many other streptococci and anaerobes www.indiandentalacademy.com
  35. 35. The normal microbial flora of different sites of the mouth Lips staph.albus and skin micro-cocci predominate with large no. of streptococci typical of mouth Cheeks predominant bacterium is strep.mitior with strep.sanguis and salivarius yeasts may isolated from carriers Palate streptococcal flora resembling cheek haemophili, lactobacilli are common yeasts and lactobacilli in denture wearers because of protected enviornment Tongue dorsal surface of the tongue is the ideal surface for retention of microorganisms predominant organisms- strep.salivarius, strep.mitior, haemophilus, small no. of C.albicans micrococcus mucilageneous…….. www.indiandentalacademy.com
  36. 36. The normal microbial flora of different sites of the mouth contd Gingival crevices -most numerous of any site in the mouth. -1010- 1011 organisms per gr. Wet wt. Of gingival debris -well protected from forces that dislodge bacteria -facultative gr+ve cocci 27, anaerobic gr+ve & gr-ve rods/filaments 40% Teeth # organisms attach through dental plaque # build up as follows - occlusal fissures and pits - in enamel defects - in interproximal spaces - close to gingival margins Saliva # microbial count of saliva 107- 108 org/ml # for many years regarded as representative of oral flora…. www.indiandentalacademy.com
  37. 37. Dentures and other intra oral appliances Any appliance worn for considerable period, become colonized with microorganisms and may alter the flora Fixed appliances supports supra gingival plaque if poorly constructed Removable appliances have advantage of being able to be cleansed properly… Yeasts & lactobacilli multiply on any mucosal surface protected from the flow of saliva Acrylic appliances retain a denser flora than metal…. large no. of C.albicans can be cultured from the fitting surfaces of the acrylic dentures. www.indiandentalacademy.com
  38. 38. The principal microorganisms of the mouth Cocci Gr+ve strep.sanguis strep.mutans strep.mitior strep.salivarius strep.milleri Gr-ve neisseria veillonella Rods/filaments Gr+ve lactobacillus corynebacterium actinomyces eubacterium arachnia propionibacterium Gr-ve haemophilus eikenella campylobacter bacteroides fusobacterium actinobacillus capnocytophaga wolinella www.indiandentalacademy.com
  39. 39. The principal microorganisms of the mouth contd Anaerobic bacteria- spirochaetes Yeasts- C.albicans, tropicalis, krusei Mycoplasma- M.orale, salivarium, faucium, buccale Protozoa- Entamoeba gingivalis, trichomonas tenax viruses www.indiandentalacademy.com
  40. 40. Dental plaque Dental plaque is defined as soft deposits that form the biofilm adhering to the tooth surface or other hard surfaces in the oral cavity, including removable and fixed restoration Dp is composed primarily of microorganisms 1gm plaque(wet wt) contains 2*1011 bacteria Meteria alba.. Plaque formation -formation of pellicle coating -initial colonization by bacteria Gr+ bacteria, act.viscous. Strep.sanguis & other streptoocci,vellonella,corynebacterium -secondary colonization and plaque maturation Grbacteria, P.intermedia, P.loscheii, capnocytophaga, fusobacteriu www.indiandentalacademy.com
  41. 41. Microbial interactions in DP Benificial or detrimental Strep.mutans, sanguis & lactobacilli lowers the ph by the fermentation of the carbohydrates to produce an environment unsuitable for other organisms like veillonella, bacteriodes Hydrogen peroxide produced by strep.mutans inhibits actinomcetes & a wide range of other microorganisms Vitamin k produced by corynebacterium stimulate the growth of bact.melaninogenicus www.indiandentalacademy.com
  42. 42. calculus Produced by calcification of supra & subgingival dental plaque Hardness varies as the deposition of calcium phosphate occurs in patches Local ph changes, saliva with super saturated solution of calcium and phosphate provides enviornment for plaque calcification Bacterionema matruchoti along with veillonella, nesseria, Haemophilus & bacteroides plays imp role……. www.indiandentalacademy.com
  43. 43. Control of dental plaque Diet Physical removal Ultrasonic scaling devices Antiseptics Antibiotics www.indiandentalacademy.com
  44. 44. Dental Caries Odontopathic Bacteria Mutans group of Streptococci Initiator of Caries Lactobacillus (acid-loving bacteria) Secondary invader www.indiandentalacademy.com
  45. 45. CARIOGENIC DENTAL PLAQUE Bacteria produce a strong acid - Lactic Acid Bacteria produce surface molecules which seal the acid against the tooth and keep the saliva from buffering the Lactic Acid Bacteria are capable of continually producing the Lactic Acid due to stores of glycogen within the bacterial cells Streptococcus mutans Early colonizer of the tooth Strong Protease Producer Removes the salivary coat from its surface Binds to Salivary coated tooth surfaces (only after removing the coat of saliva on its surface) www.indiandentalacademy.com
  46. 46. LACTOBACILLUS Acidophilic (acid-loving) environments (Inside Deep Carious Lesions) { pH = 5.3 4.5 pH = 4.5 3.7 { LACTOBACILLU S www.indiandentalacademy.com
  47. 47. Dental caries Microbiological aspect of caries prevention diet plaque control immunisation against dental caries based on belief that most carious lesions are initiated by strep.mutans vaccine to stimulate production of antibodies to organism, which can then reach the site where caries is likely to develop and so exert a protective effect www.indiandentalacademy.com
  48. 48. Periodontal disease Acute ANUG periodontal abscess Chronic gingivitis periodontitis juvenile periodontitis www.indiandentalacademy.com
  49. 49. Periodontal disease contd ANUG Characterized by the destruction of interdental papillae and often gingival margin Isolated organisms are Borrella vincenti fusobacterium fusiforme bact.melaninogenicus Treatment careful oral hygiene measures metronidazole Periodontal abscess organisms isolated Bact.gingivalis Anaerobic cocci, Facultative cocci, actinomyces www.indiandentalacademy.com
  50. 50. Periodontal disease contd Gingivitis Inflammation of gingivae appears to be caused by bacteria and their products in dental plaque to gingival margin Acute inflammatory response with dilatation of gingival capillaries and exudaation of fluid containing IgG, complement,and PMN’s No particular organism have been implicated…. Removal of dp… Act.viscosus/naeslundi www.indiandentalacademy.com
  51. 51. Periodontal disease contd chronic periodontitis Gingivitis if not controlled leads to periodontitis Attachment of junctional epithelium to the tooth migrates apically and gingival pocket forms This deepened pocket is colonised by dp bacteria and so a progressive deepening of the pocket ensues In the advance lesion the chronic inflammatory response leads to destruction of collagen ane bone supporting the tooth. Organisms isolated anaerobic especially bact.gingivalis, eikenella corrodens,spirochaetes, bact.melaninogenicus, act.viscous/naeslundi, act.israell i, veillonella Treatment control of plaque elimination of pockets that cannot be kept clean antibiotics have no role www.indiandentalacademy.com
  52. 52. Juvenile periodontitis Some young patients develop a degree of pdl destruction well in advance of that expected for their age Two organisms predominate -actinobacillus actinomycetem comitans -capnocytophaga Both organisms appear to promote the destruction of fibroblasts and activity of osteoclasts www.indiandentalacademy.com
  53. 53. Bacterial infections of oral cavity Syphilis Actinomycoses Tuberculosis Diphteria Scarlet fever Leprosy Tetanus www.indiandentalacademy.com
  54. 54. Candidiasis (oral thrush) Caused by candida albicans Common inhabitant of oral cavity Most opportunistic infection in world Causes- inadverent use of antibiotics, immunosupressive drugs Eg. Corticosteroids, cytotoxic drugs C/F – soft, white, slightly elavated plaque on buccal mucosa, tongue. plaque can be wiped away with gauze leaving erythematous area AIDS patients suffer andrugs nystatin, chlortrimazoles, amphotericin Rx – antifungal intractable form of oral thrush, caused by a newlydescribed species, Candida dubliniensis. This organism is more resistant to B, Iconozole antifungal therapy than Candida albicans. AIDS patients may also present with Kaposi sarcoma tumours in the oral cavity. www.indiandentalacademy.com
  55. 55. Types of Candidiasis Pseudomembranous candidiasis Thrush Hyperplastic candidiasis Atrophic candidiasis www.indiandentalacademy.com
  56. 56. Viral infections of oral soft tissues HSV-1 and/or HSV-2 Primary Infection Secondary Infection Varicella zoster virus (HHV-3) Herpesvirus Infection Primary Infection Herpetic gingivostomatitis Younger patients Often asymptomatic May be associated with fever, chills, malaise Vesicles-ulcers-crusting Anywhere in the oral cavity www.indiandentalacademy.com
  57. 57. Herpesvirus Infection Secondary Infection Reactivation of latent virus Not associated with systemic symptoms Small vesicles Occur only on the hard palate and gingiva Prodromal signs Varicella zoster virus www.indiandentalacademy.com
  58. 58. Herpangina NOT caused by Herpesvirus Coxsackie A virus Children < 10 years of age Common in summer and fall Often subclinical presentation Headache/Abdominal pain 48hrs prior to papulovesicular lesions on tonsils and uvula. Sore throat www.indiandentalacademy.com
  59. 59. Why Is Infection Control Important in Dentistry? Both patients and dental health care personnel (DHCP) can be exposed to pathogens Contact with blood, oral and respiratory secretions, and contaminated equipment occurs Proper procedures can prevent transmission of infections among patients and DHCP www.indiandentalacademy.com
  60. 60. Modes of Transmission Direct contact with blood or body fluids Indirect contact with a contaminated instrument or surface Contact of mucosa of the eyes, nose, or mouth with droplets or spatter Inhalation of airborne microorganisms www.indiandentalacademy.com
  61. 61. Standard Precautions Apply to all patients •Elements of Standard Precautions Handwashing Use of gloves, masks, eye protection, and gowns Patient care equipment Environmental surfaces Injury prevention www.indiandentalacademy.com
  62. 62. Personal Protective Equipment , www.indiandentalacademy.com
  63. 63. Sterilization and Disinfection of Patient Care Items Critical Instruments Penetrate mucous membranes or contact bone, the bloodstream, or other normally sterile tissues (of the mouth) Heat sterilize between uses or use sterile single-use, disposable devices Examples include surgical instruments, scalpel blades, periodontal scalers, and surgical dental burs •Semi-critical Instruments Contact mucous membranes but do not penetrate soft tissue Heat sterilize or high-level disinfect Examples: Dental mouth mirrors, amalgam condensers, and dental handpieces www.indiandentalacademy.com
  64. 64. Noncritical Instruments and Devices Contact intact skin Clean and disinfect using a low to intermediate level disinfectant Examples: X-ray heads, facebows, pulse oximeter, blood pressure cuff •Saliva Ejectors Previously suctioned fluids might be retracted into the patient’s mouth when a seal is created Do not advise patients to close their lips tightly around the tip of the saliva ejector www.indiandentalacademy.com
  65. 65. Preprocedural Mouth Rinses Antimicrobial mouth rinses prior to a dental procedure Reduce number of microorganisms in aerosols/spatter Decrease the number of microorganisms introduced into the bloodstream Oral Surgical Procedures Present a risk for microorganisms to enter the body Involve the incision, excision, or reflection of tissue that exposes normally sterile areas of the oral cavity Examples include biopsy, periodontal surgery, implant surgery, apical surgery, and surgical extractions of teeth www.indiandentalacademy.com
  66. 66. Extracted Teeth Considered regulated medical waste Do not incinerate extracted teeth containing amalgam Clean and disinfect before sending to lab for shade comparison Can be given back to patient Handling Extracted Teeth in Educational Settings Remove visible blood and debris Maintain hydration Autoclave (teeth with no amalgam) www.indiandentalacademy.com
  67. 67. Automated Cleaning Ultrasonic cleaner Instrument washer Washer-disinfector Manual Cleaning Soak until ready to clean Wear heavy-duty utility gloves, mask, eyewear, and protective clothing www.indiandentalacademy.com
  68. 68. Heat-Based Sterilization Steam under pressure (autoclaving) Dry heat Unsaturated chemical vapor Liquid Chemical Sterilant/Disinfectants Only for heat-sensitive instruments Powerful, concerns toxic chemicals raise safety Heat tolerant or disposable alternatives are available www.indiandentalacademy.com
  69. 69. Disinfectants Disinfectants are chemicals that destroy or inactivate most species of pathogenic (disease-causing) microorganisms. In dentistry, only those products that are Environmental Protection Agency (EPA)-registered hospital disinfectants with tuberculocidal claims (kills the tuberculosis bacteria) should be used to disinfect dental treatment areas. The Mycobacterium tuberculosis is highly resistant to disinfectants, and if a disinfectant will inactivate the M. tuberculosis, it will most certainly inactivate the less resistant microbial families (such as bacteria, viruses, and most fungi) on the treated surface. www.indiandentalacademy.com
  70. 70. Environmental Surfaces May become contaminated Not directly involved in infectious disease transmission Do not require as stringent decontamination procedures Clinical contact surfaces High potential for direct contamination from spray or spatter or by contact with DHCP’s gloved hand Housekeeping surfaces Do not come into contact with patients or devices Limited risk of disease transmission www.indiandentalacademy.com
  71. 71. Clinical Contact Surfaces www.indiandentalacademy.com
  72. 72. Housekeeping Surfaces www.indiandentalacademy.com
  73. 73. Cleaning Clinical Contact Surfaces Risk of transmitting infections greater than for housekeeping surfaces Surface barriers can be used and changed between patients OR Clean then disinfect using an low- (HIV/HBV claim) to intermediate-level (tuberculocidal claim) hospital disinfectant Cleaning Housekeeping Surfaces Routinely clean with soap and water or an detergent/hospital disinfectant routinely Clean mops and cloths and allow to dry thoroughly before re-using Prepare fresh cleaning and disinfecting solutions daily and per manufacturer recommendations www.indiandentalacademy.com
  74. 74. Infection control in dental laboratory Potential for disease transmission in the dental lab is well documented Potential pathogens can be transported to lab via orally soiled impressions, dental prostheses/appliances Microorganisms can be transferred from contaminated impressions to dental casts Oral bacteria can remain viable in set gypsum for up to 7 days BASICS OF LABORATORY IC Need coordination between dental office and lab Use of proper methods/materials for handling and decontaminating soiled incoming items All contaminated incoming items should be cleaned and disinfected before being handled by lab personnel, and before being returned to the patient www.indiandentalacademy.com
  75. 75. MASK/PROTECTIVE EYEWEAR/CLOTHING Must be used when there is potential for splashes, spray, spatter, or aerosols Examples: when operating lathes, model trimmers, and other rotary equipment Lab coat/jacket should be worn at all times during fabrication process Change daily Do not wear outside of the lab Launder appropriately www.indiandentalacademy.com
  76. 76. IMPRESSIONS Many studies have been performed to evaluate effects of various disinfectants on different types of impression materials Research findings have been contradictory No single disinfectant is compatible with all impression materials The least distortion is associated with products having the shortest contact times www.indiandentalacademy.com
  77. 77. IMPRESSIONS Many variables can affect impression materials Composition and concentration of disinfectants Exposure time and compatibility of various disinfectants with specific impression materials Physical/chemical properties can vary in a given category of material or disinfectant Consult dental materials’ manufacturers regarding their compatibility with disinfectants www.indiandentalacademy.com
  78. 78. DISINFECTING IMPRESSIONS Methods Spraying, immersing Exposure time should be that recommended by the manufacturer of disinfectant for tuberculocidal disinfection Iodophors, sodium hypochlorite (1:10 concentration), chlorine dioxide, phenols, and other approved products are all acceptable www.indiandentalacademy.com
  79. 79. DISINFECTING IMPRESSIONS Polyether materials cannot be immersed in disinfectants due to potential for absorption and distortion Immersion disinfectants can only be used once before discarding (except for glutaraldehydes) Most reports indicate dimensional stability is not significantly affected by immersion technique Clean and rinse impression in dental operatory Cleaning efficiency can be improved by gently scrubbing impression with camel’s hair brush and antimicrobial detergent  Sprinkle dental stone into impression before rinsing to aid in cleaning Cleaning and rinsing  Reduces bioburden present  Lessens overall microbiologic challenge to disinfectant www.indiandentalacademy.com
  80. 80. DENTAL CASTS Very difficult to disinfect It Is preferable to disinfect impression If casts must be disinfected: Place casts on end to facilitate drainage Spray with iodophor or chlorine product, then rinse Another option Soak casts for 30 minutes in 0.5% concentration of sodium hypochlorite and saturated calcium dihydrate solution (SDS) SDS is produced by placing uncontaminated, set gypsum (i.e. stone) in a container of water www.indiandentalacademy.com
  81. 81. ORALLY SOILED PROSTHESES Scrub with brush and antimicrobial soap to remove debris and contamination Can be accomplished in operatory or professional work area Sterilize brush or store in approved disinfectant Place prosthesis in sealable plastic bag or beaker filled with ultrasonic cleaning solution or calculus remover Place in ultrasonic cleaner for required time as specified by manufacturer of ultrasonic cleaner Place cover on ultrasonic cleaner to reduce spatter potential Remove and rinse under running tap water, dry, and accomplish required work www.indiandentalacademy.com
  82. 82. LATHE Ways to reduce risk of injury from aerosols, spatter, and macroscopic particles Use protective eyewear Ensure plexiglass shield is in position Machine should be cleaned and disinfected daily No need for separate pans for new and existing prostheses if isolated properly At a minimum clean and disinfect pumice brushes and rag wheels daily. Daily heat sterilization is preferable. Change pumice daily www.indiandentalacademy.com
  83. 83. IMPRESSION TRAYS Precleaning removes bioburden and any adherent impression material Ultrasonic cleaning can aid in removing residual set gypsum Chrome-plated or aluminum trays Clean, package, heat sterilize Single-use trays Discard after one use Custom acrylic trays Can be disinfected (by spray or immersion), then rinsed (if to be used for second appointment) www.indiandentalacademy.com
  84. 84. DISINFECTION Prosthodontic items contaminated by handling should be disinfected (by spray or immersion technique based on type of item) after each use Examples: alcohol torch, facebow, articulator, mixing spatula, mixing bowl, lab knife, shade/mold guide WAX BITES/RIMS, BITE REGISTRATIONS Immersion disinfection may cause distortion to some items  Use spray disinfection Heavy-body bite registration materials Usually not susceptible to distortion and can be disinfected in same manner as an impression of the same material  www.indiandentalacademy.com
  85. 85. PERSONAL HYGIENE Refrain from the following activities while in the lab where there is potential for occupational exposure: Eating Drinking Smoking Applying cosmetics or lip balm Handling contact lenses www.indiandentalacademy.com
  86. 86. conclusion Very few microbes are always pathogenic Many microbes are potentially pathogenic Most microbes are never pathogenic www.indiandentalacademy.com
  87. 87. References Text book of microbiology; 5th edition: ananthnarayan Medical bacteriology; key and key Oral microbiology & immunology; Micheal G Newmann Microbiology in clinical dentistry; Frank J Orland Clinical & oral microbiology; PW Ross Clinical periodontology- Carranza J periodontology 1971;42:485-94 Oral pathology: Shafer Control of infection guidelines; 2 nd edition:NHS www.indiandentalacademy.com
  88. 88. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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