Notes

Outline

DENTAL CARIES

Jim M 25 yo WM Tx 6 mo previously for extensive caries Left office with no caries evident and no periodontal problems He comes in today for his 6 month checkup

"Severe gingival recession" Severe gingival recession Extensive caries on roots of almost all teeth

Exam No obvious job related cause He brushed his teeth every day There was no change in diet He rarely ate candy and didn’t drink soda pop He did ask for a glass of water several times

"So" So  what else do we ask this man?

"Caries can affect any and..." Caries can affect any and all surfaces of a tooth

INTRODUCTION Dental caries is a slow decomposition of teeth resulting from the loss of hydroxyapatite crystals due to lactic acid produced by the bacteria residing in the plaque that is attached to the surface of the tooth

"These bacteria must," These bacteria must, therefore, be Acidogenic Aciduric

"Caries is the result of..." Caries is the result of the interaction of microorganisms with the host, in this case the teeth, in an environment that supplies a fermentable substrate (sugar) over a period of time All four of these factors must be present in order for caries to develop

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"Approximately 500 species of bacteria..." Approximately 500 species of bacteria have been identified in the plaque The ones causing tooth decay are not known for certain But we do have circumstantial evidence for some organisms

HISTORY

Prior to Identification of Specific Organisms Prior to 1890 it was believed that mineral acids that formed from food residues were responsible for tooth decay There was no connection with bacteria

"1890 - W.D." 1890 - W.D. Miller formed the chemoparasitic theory of caries Microorganisms attach to the tooth and produce organic acids which dissolve the enamel

34 years later 1924 - Clarke isolated a strep from approx. 72% of carious lesions Formed rods in old cultures and therefore he called it S. mutans, but it's not a mutation (genetic change) It is a phenotypic reaction to the conditions in the old culture medium

9 years later 1933 - Tomato juice agar was used to count oral lactobacilli Higher numbers were found in mouths with caries Similar results with other media selective for the lactobacilli gave rise to the belief that lactobacilli were THE cause of tooth decay

23 years later 1955 A diet that could produce caries in normal animals couldn't cause caries in germfree animals Therefore caries was proven to be caused by bacteria

"Also" Also Germ-free animals, when inoculated with enterococci, could get caries Therefore, not just lactobacilli

5 years later 1960 - Fitzgerald & Keyes Isolated a strep from human caries that was cariogenic in hamsters

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"Therefore caries was shown to..." Therefore caries was shown to be a communicable disease, at least in hamsters

2&3 years later 1967 & 1968 - Carlsson & Edwardson worked on the taxonomy of the various cariogenic streptococci

"They found that the strains..." They found that the strains resembled the previously described S. mutans of Clarke and officially named the cariogenic streptococci "Streptococcus mutans”

"They also found that characteristics..." They also found that characteristics which distinguished the S. mutans from all other strep were their ability to ferment mannitol and sorbitol produce insoluble glucan from sucrose

After Identification of Specific Organisms 1970 & 1972 – two people worked with S. mutans isolates Bratthall identified 4 groups based on serology Coykendall identified 4 groups based on DNA base content

"Cultures identified by the 2..." Cultures identified by the 2 methods correlated perfectly and gave rise to 4 subspecies of S. mutans which have now been elevated to species status

Present day human species of  the former Streptococcus mutans Species Serogroup Mannitol Sorbitol S. Mutans c e f + + S. Sobrinus d g + + S. Rattus b + + S. cricetus a b + +

Present day human species of  the former Streptococcus mutans Species Serogroup Mannitol Sorbitol S. mutans S. sobrinus S. rattus S. cricetus

"In the 1970s," In the 1970s, Irving Sklair in Great Lakes, Illinois Naval Training Center studied S. mutans-free and caries-free individuals Found they could become infected Therefore caries was shown to be a communicable disease for humans

TYPES OF CARIES

We can identify 7 different types of dental caries 1) Normal Buccal-Lingual Smooth Surface Enamel Caries - the tooth decay on the sides of the tooth next to the tongue and cheek

"2)" 2) Normal Interproximal Smooth Surface Enamel Caries - the tooth decay on the enamel surfaces between the teeth

"3)" 3) Rampant Smooth Surface Enamel Caries - similar to normal smooth surface enamel caries except It occurs VERY quickly Often leaves the teeth severely damaged in a few months

"4)" 4) Pit & Fissure enamel caries - the caries occurring on the molar teeth where they contact the other molars

"5)" 5) Normal Cementum Caries - caries that occurs on the cemental surface of the tooth that is normally located below the gum line

"Cementum only becomes involved after..." Cementum only becomes involved after it is exposed Usually during older age Can be exposed if someone brushes their teeth too hard by using a hard bristled brush

"6)" 6) Rampant Cementum Caries - similar to Rampant Smooth Surface Enamel Caries It occurs VERY quickly Often leaves the teeth severely damaged in a few months

"7)" 7) Dentin Caries - the caries that occurs after the enamel or cementum is lost due to decay or other means We know least about this stage / type of dental caries

Caries type Enamel Smooth Surface Normal Buccal-Lingual   Normal Interproximal Rampant Pit & Fissure Cementum Normal Rampant Dentin

ORGANISMS INVOLVED

3 Genera We have a lot of circumstantial evidence for organisms in three genera as the initiators of caries: Streptococcus Lactobacillus Actinomyces

Species Most evidence indicates that the various forms of enamel and cemental caries are caused by 4 streptococci: S. mutans S. sobrinus S. rattus S. cricetus

"These 4 Streptococci," These 4 Streptococci, once all classified as S. mutans, then reclassified as separate species Are now often all referred to as “S. mutans” or “the S. mutans group”

"Enamel and cemental caries are..." Enamel and cemental caries are also caused by 4 lactobacilli: L. casei L. fermentum L. plantarum L. acidophilus and 3 actinomyces: A. viscosus A. naeslundii A. odontolyticus

"The organisms involved in dentinal..." The organisms involved in dentinal caries have only recently been examined and conclusions are tentative at this point

TYPES OF CARIES Smooth Surface Pit & Fissure Cemental (Root) Dentinal Each type of caries appears to have its own etiologic flora

Smooth Surface Normal Buccal-Lingual smooth surface caries = S. mutans group Normal Interproximal Smooth Surface caries is = S. mutans and lactobacilli Rampant Smooth Surface caries = S. mutans group

Pit & Fissure Pit & Fissure caries = S. mutans group and Lactobacillus spp.

Cemental (Root) Cemental or root caries = A. viscosus; A. naeslundii, A. odontolyticus, Filamentous rods; and the S. mutans group

Dentinal Dentinal caries occurs after enamel or cemental caries exposes the dentin Here we find a new set of organisms - mostly Gram-positive rods

"Most often linked to dentinal..." Most often linked to dentinal caries = Lactobacillus spp. A. viscosus A. naeslundii Eubacterium spp. Arachnia spp. Bifidobacterium spp. Propionibacterium spp. Filamentous rods

"Organisms of the S." Organisms of the S. mutans group have also been isolated but in low numbers when present

HOW ORGANISMS PRODUCE ACID AND PLAQUE

"How do these organisms produce" How do these organisms produce the  plaque that binds the organisms to the teeth the acid that dissolves the enamel

Naming of Sugars SUGAR POLYMER

"Sucrose = Glucose + Fructose" Sucrose = Glucose + Fructose

Streptococcus

S. mutans Metabolism of Sugars Glucose à (Glucosyl Transferase) à Glucans/Dextrans (Insoluble) Glucose à Acid - Rapid production, pH <5.5 Fructose à (Fructosyl Transferase) à Fructans/Levans (soluble) Fructose à Acid - Rapid production, pH < 5.5 pH 5.5 = pH at which enamel dissolves

S. mutans Metabolism of Sugars Glucose à (Glucosyl Transferase) à Glucans/Dextrans (Insoluble) Glucose à Acid - Rapid production, pH <5.5 Fructose à (Fructosyl Transferase) à Fructans/Levans (soluble) Fructose à Acid - Rapid production, pH < 5.5 pH 5.5 = pH at which enamel dissolves

"Sucrose à Acid - Rapid..." Sucrose à Acid - Rapid production, pH <5.5 à Plaque Glucose à Acid - Rapid production, pH <5.5 Fructose à Acid - Rapid production, pH <5.5 Others à Acid - Rapid production, pH <5.5

S. mutans Only sucrose results in an insoluble glucose polymer (plaque) The energy in the bond between the glucose and fructose is needed for the polymerization Thus, glucose or fructose or a mixture of the two will not result in plaque formation

"Small amounts of sucrose favor..." Small amounts of sucrose favor acid production over polymer production Large amounts of sucrose favor glucan synthesis, plaque, and caries

"The glucan made by S" The glucan made by S. mutans has been named “mutan”, although that name is rarely used Originally it was thought to be and was called “dextran”, but dextran has a slightly different chemical structure

"Whatever amount of sucrose or..." Whatever amount of sucrose or other sugar is ingested, acid is produced very rapidly and the pH goes down to about 4 or 5, which is low enough for enamel to demineralize (<5.5)

"The rate of acid formation..." The rate of acid formation is significant because the buffering action of the saliva will neutralize the acid if it is only produced slowly

"This ability to produce plaque..." This ability to produce plaque and a low pH gives S. mutans the ability to INITIATE caries on smooth surfaces, pits and fissures, and on root surfaces

"Of the mutans strep," Of the mutans strep, S. sobrinus and S. mutans are most often involved in human caries Of these 2 streptococci, studies have found a greater amount of decay in people infected with S. sobrinus than with S. mutans

Lactobacillus

Cariogenic lactobacilli L. casei L. fermentum L. plantarium L. acidophilus L. salivarius L. oris L. grasseri L. brevis

Lactobacillus Metabolism of Sugars Sucrose à Acid - Rapid production, pH <5.5 Glucose à Acid - Rapid production, pH <5.5 Others à Acid - Rapid production, pH <5.5

"Because the lactobacilli don't produce..." Because the lactobacilli don't produce any significant polymer, they must be mechanically retained  (Not a plaque former)

"They can initiate Pit &..." They can initiate Pit & Fissure caries in germ free animals but can't initiate smooth surface caries in the absence of a retention area such as braces provide They can participate once the initial caries lesion is formed by S. mutans

"As with the streptococci," As with the streptococci, whatever amount of sucrose or other sugar is ingested, acid is produced vary rapidly and the pH goes down enough to demineralize the enamel

"But," But, because they don't form plaque, they CAN’T INITIATE smooth surface caries But they can PARTICIPATE in smooth surface and root surface lesions, once formed They CAN INITIATE pit and fissure caries and interproximal caries

Actinomyces

Actinomyces 3 cariogenic Actinomyces species A. viscosus A. naeslundii A. odontolyticus These organisms produce levans from sugars

Actinomyces Metabolism Of Sugars Sucrose à levans (soluble) à Acid - Slow production, pH >5.5 Others  à Acid - Slow production, pH >5.5

"The actinomycetes are able to..." The actinomycetes are able to form a small amount of plaque in the absence of sugars These organisms don't produce enough acid fast enough to initiate enamel caries but it is sufficient to lower the pH enough to cause cemental or root caries

"By age 7," By age 7, 70% of children are colonized with the Actinomyces organisms which selectively localize at the gingival margin Cemental, or root caries usually occurs during later life, when the gingivae recede due to periodontal disease and expose the cementum

"So this isn't a disease..." So this isn't a disease caused by an infection with a newly acquired organism The organisms have been there since early childhood

Other Organisms

"Are there other organisms that..." Are there other organisms that can cause caries

"The organisms in the next..." The organisms in the next table were isolated from the oral cavity Extracted, sterile teeth were suspended in test tubes of broth containing sucrose, glucose, and fructose The broths were then inoculated with these organisms with the results shown in the table

Plaque production and demineralization Organism Plaque Demineralize Neisseria + – C. albicans + – Corynebacterium + – Nocardia + – Leptotrichia dentium (+) – S. mitis – + L. casei – + S. salivarius + + S. mutans + + E. faecalis + + S. aureus + + S. epidermidis + +

"This experiment showed that a..." This experiment showed that a number of oral organisms can either form plaque, demineralize teeth, or do both

Rampant Caries

"Rampant Caries can occur on..." Rampant Caries can occur on any tooth surface It is characterized by a rapid dissolution of the tooth It is not due to different organisms It is due to the S. mutans group and probably also the Lactobacilli

"The rapid progression is due..." The rapid progression is due to the frequency of ingestion of sucrose or other fermentable sugar

"Rampant caries is called baby..." Rampant caries is called baby bottle syndrome when it occurs in babies Characteristically the parents leave the baby bottle in the crib for a long time Most severe when the bottle is filled with a sucrose solution such as Koolaid

"Can occur at any age..." Can occur at any age but most typically occurs in bottle-fed babies and is called baby bottle syndrome or baby bottle caries for that reason In a child it may be due to eating a lot of candy or other sweets

Further Associations of Organisms with Location of Lesion

Enamel S. mutans and lactobacilli appear to be the main organisms involved in enamel caries

Root Surface Syed and Loesche studied the bacteria present in root caries.  They found 2 kinds of plaque 1. S. mutans = 30% of the total flora A. viscosus = 47%. 2. S. mutans = not detected A. viscosus = 41% S. sanguis = 48%

"The conclusion:" The conclusion: root caries may be caused by A. viscosus alone or together with S. mutans

Dentinal We know that S. mutans can cause complete carious breakdown of the teeth, including the dentin, in animals But what is happening in human teeth? Does the S. mutans just continue burrowing its way inward?

The predominant cultivable organisms in the advancing front of caries in dentin Organisms Mean % Gram + AnO2 rods 44 Arachnia species 12 Bifidobacterium species   9 Eubacterium species 11 Propionibacterium species 11

"Organisms" Organisms Mean % Gram + Facultative  rods 38    Actinomyces species 5    Lactobacillus species 33 Gram + AnO2 cocci   7    Peptostreptococcus species 7 Gram + Facultative cocci   6    Streptococcus species 6

"Here we can see that..." Here we can see that some of the standard organisms are involved but others may also be involved As soon as we get past the surface of the enamel lesion, things get more complex Here Gram-positive anaerobic rods and cocci outnumber the facultative rods and cocci

"It would appear that we..." It would appear that we have a good deal of knowledge regarding the initiation of enamel caries but we have a long way to go in our understanding of the progression of the total carious process

Infectivity of S. mutans or its Communicability

"Naval Training Base at Great..." Naval Training Base at Great Lakes, IL Initial dental exams revealed a small percentage of newly arrived recruits/enlistees were caries-free

"The big question was:" The big question was: Were these men immune to caries Dr. Irving Sklair, a microbiologist at the base, sought to answer that question

"Studies of S." Studies of S. mutans colonization showed that if >108 S. mutans were introduced into the mouths of volunteers with normal diets, there was no colonization But if the volunteers sucked a sugar cube each hour of the first day or so, colonization occurred

"When S." When S. mutans was implanted in one quadrant using dental floss and sucrose It was rarely found on the other side of the mouth or even on adjacent teeth

"Initially caries free," Initially caries free, S. mutans free naval recruits usually acquired S. mutans and carious lesions, though this didn't always occur It was concluded that all these recruits weren't immune to S. mutans, - they just didn't have S. mutans in their mouths or weren’t eating a cariogenic diet

"Additional studies by others have..." Additional studies by others have shown Babies get the same strain of S. mutans as their mothers Therefore, in humans, caries is communicable

"In still another study it..." In still another study it was found that caries-free people could detect sucrose at a lower concentration than caries active people This may well be a conditioning rather than a genetic trait

Acid vs Proteolysis vs Enzymes in Cariogenesis Theories of caries formation

Acidogenic theory This is the most popular theory today The cariogenic bacteria can cause the plaque pH to drop below pH 5.5, which is the critical pH for dissolution of enamel (apatite)

Proteolytic theory This theory assumes that caries is initiated by plaque proteolytic enzymes that destroy the inter-rod organic material and destabilize the apatite crystals There is not much support for this theory

Proteolysis-Chelation theory This theory is based on the concept that enamel demineralization can occur without acid if complexing agents, such as lactate, decrease calcium ions surrounding the enamel crystal  and shift the equilibrium toward dissolution

Proteolysis-Chelation theory There is not much support for this theory

Enzymatic theory This theory is based  on the fact that plaque bacteria produce enzymes

Enzymatic theory Enzymes involved may include: Phosphatase - dissolves apatite Chondroitin sulfatase - dissolves dentinal chondroitin sulfate Hyaluronidase - dissolves dentinal hyaluronic acid Proteases - dissolve dentinal collagen

"All these enzymes are produced..." All these enzymes are produced by plaque bacteria There is little support for this theory as the only cause of caries but by combining it with the Acidogenic theory you get the

Acid-Enzyme theory This theory is a combination of the acidogenic and the enzyme theories Acid is most  likely the major factor in enamel dissolution Enzymes probably play a greater role in dentinal dissolution

Caries Control

Mechanical Brush and Floss at least 2 times per day

Diet Limit Sucrose Intake - Most Important of all measures

Chemical Xylitol - S. mutans doesn’t metabolize xylitol Consumption of a xylitol containing diet reduced the caries incidence in humans by 90%

Chemical Xylitol Just last year it was shown that mothers that chewed xylitol containing chewing gum reduced the transmission of S. mutans to their children

"Aspartame - not cariogenic" Aspartame - not cariogenic Inhibited caries in animals when added to a cariogenic diet

"Fluorides - best if in..." Fluorides - best if in drinking water Gels, toothpaste, and mouthwashes are also good They become incorporated into apatite of enamel and make it more resistant to acid breakdown

"Peridex - chlorhexidine gluconate" Peridex - chlorhexidine gluconate Excellent plaque preventive Attaches to apatite and therefor is most effective if applied after a prophy (tooth cleaning) Requires daily application May stain pellicle

"Antimicrobic varnishes (Pit &..." Antimicrobic varnishes (Pit & Fissure sealants) - have successfully eliminated S. mutans They need periodic replacement

"Antibiotic Gels - Vancomycin and..." Antibiotic Gels - Vancomycin and Kanamycin in a gel have had some success in eliminating S. mutans

Biological Bacteriocins - inhibited caries in an animal model using S. mutans

"Ecological Immunization-using non-pathogenic..." Ecological Immunization-using non-pathogenic S. mutans-one that can’t convert pyruvic acid to lactic acid In a limited trial in humans it was implanted and it inhibited implantation of a cariogenic strain

"Normal Immunization" Normal Immunization Is complicated by there being several species and serological types IV and SubQ don't produce effective immunity

"Injection in the submandibular region..." Injection in the submandibular region with whole, killed S. mutans resulted in SIgA vs. S. mutans and, in monoinfected animals, resulted in lower mean caries scores But this didn't totally prevent caries Similar results were produced by oral immunization with S. sobrinus (mutans) glucosyltransferase

"Immunization with whole cells of..." Immunization with whole cells of S. mutans has produced an antibody reaction to heart tissue in animals This greatly inhibited research in this area but newer methods using purified cell components do not have this effect

"Immunization against other potential etiologic..." Immunization against other potential etiologic agents hasn't been tried

Summary

Bacteria Associated with Caries Types Smooth Surface Streptococcus mutans (group) Pit & Fissure Streptococcus mutans Lactobacillus spp. Root Actinomyces viscosus Filamentous rods Actinomyces naeslundii Streptococcus mutans Actinomyces odontolyticus Dentinal Lactobacillus spp. Arachnia spp. Actinomyces viscosus Bifidobacterium spp. Actinomyces naeslundii Propionibacterium spp. Filamentous rods Streptococcus mutans Eubacterium spp.

"The streptococci and lactobacilli can..." The streptococci and lactobacilli can initiate caries when supplied with an abundance of a fermentable sugar, especially sucrose They produce a lot of acid and can dissolve the tooth enamel rather quickly In addition, the mutans streptococci produce plaque, making the situation even worse

"The actinomyces," The actinomyces, on the other hand, plod along slowly, producing small amounts of acid from almost any sugar They are able to initiate lesions only on the softer cementum below the gum line but are able to slowly decay the dentin of a tooth if it is first exposed by some trauma or other bacteria

Jim M Has rampant root caries Organism: S. mutans Why gingival recession? Why caries in the absence of candy and soda pop?

Jim M Gingival recession: Due to brushing with hard bristled brush 3x / day Caries: Diet included sweet rolls and pie Bottomless cup of coffee with 3 spoonfuls of sugar

Jim M Could have been prevented with Diet counseling Proper oral hygiene instruction

Jim M Why did Jim M need/desire several cups of water during the exam? He had a cold Was taking an antihistamine cold medication which dried his sinuses, and dried out his mouth

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