Summary of Lecture # 2 October 3, 2007 Abdullah S. Al-Swuailem BDS, MS, MPH, Dr PH.

Summary of Lecture Summary of Lecture # # 22

October 3, 2007October 3, 2007

Abdullah S. Al-Swuailem BDS, MS, MPH, Dr PHAbdullah S. Al-Swuailem BDS, MS, MPH, Dr PH

Bacterial PlaqueBacterial Plaque

- Biolfim bacteria behave differently from Planktonic Biolfim bacteria behave differently from Planktonic (liquid-phase) cells. Bacteria growing in biofilm are (liquid-phase) cells. Bacteria growing in biofilm are more resistant to host defence mechanisms and more resistant to host defence mechanisms and exogenous antimicrobial agents. Thus mechanical exogenous antimicrobial agents. Thus mechanical removal of bacterial biofilm is needed to have removal of bacterial biofilm is needed to have effective antimicrobial therapyeffective antimicrobial therapy

- subsurface pellicle vs. acquired pellicle - subsurface pellicle vs. acquired pellicle


Factors influencing the build-up of dental Factors influencing the build-up of dental plaque:plaque:

1.1. Mechanical displacement (chewing, tongue Mechanical displacement (chewing, tongue movement, oral hygiene aids)movement, oral hygiene aids)

2.2. Stagnation (colonization in sheltered Stagnation (colonization in sheltered environments, e.g. inter-proximal area)environments, e.g. inter-proximal area)

3.3. Availability of nutrientsAvailability of nutrients4.4. Interactions between the microbes and the Interactions between the microbes and the

host’s inflammatory immune system host’s inflammatory immune system


Plaque formation:Plaque formation:- Within 2 hours, initial plaque formation begins as a Within 2 hours, initial plaque formation begins as a

series of isolated bacterial colonies confined to tooth series of isolated bacterial colonies confined to tooth surface irregularitiessurface irregularities

- In about 2 days, the plaque double in mass and In about 2 days, the plaque double in mass and bacterial colonies coalesce bacterial colonies coalesce

- In the first 4-5 days of plaque formation, the number In the first 4-5 days of plaque formation, the number of bacteria increase significantlyof bacteria increase significantly

- After approximately 21 days, bacterial replication After approximately 21 days, bacterial replication slows so that plaque accumulation becomes relatively slows so that plaque accumulation becomes relatively stable. Bacteria in the deeper portion of the stable. Bacteria in the deeper portion of the developing plaque are either facultative or obligate developing plaque are either facultative or obligate anaerobesanaerobes


Dental calculus:Dental calculus:- Supra-gingival calculus: Supra-gingival calculus: - located coronal to gingival margin and frequently located coronal to gingival margin and frequently

develops opposite to duct orifices of major salivary glands. develops opposite to duct orifices of major salivary glands. 30% mineralized. Yellow to white chalky mass30% mineralized. Yellow to white chalky mass

- Sub-gingival calculus:Sub-gingival calculus:- Located below the gingival margin and derived its Located below the gingival margin and derived its

minerals from crevicular fluids within the gingival sulcus. minerals from crevicular fluids within the gingival sulcus. It is thinner and harder (60% mineralized) than supra-It is thinner and harder (60% mineralized) than supra-gingival calculus. Gray to black in color.gingival calculus. Gray to black in color.

- Calculus formation can be inhibited by using agents Calculus formation can be inhibited by using agents containing pyrophosphate or metal ions such as zinc containing pyrophosphate or metal ions such as zinc

Dental CariesDental Caries

Learning objectives:Learning objectives: - Be able to define the dental caries and know the different types of Be able to define the dental caries and know the different types of

dental caries and the process of disease initiation and progressiondental caries and the process of disease initiation and progression- Know the risk factors associated with root cariesKnow the risk factors associated with root caries- Explain how Stephan’s curve is plotted and its significanceExplain how Stephan’s curve is plotted and its significance- Recognize methods to prevent dental cariesRecognize methods to prevent dental caries- Know the difference between gingivitis and periodontitisKnow the difference between gingivitis and periodontitis- Understand how periodontal disease can be preventedUnderstand how periodontal disease can be prevented


Definition of tooth cavitation: localized , post-Definition of tooth cavitation: localized , post-eruptive pathological process involving bacterial eruptive pathological process involving bacterial acid demineralization of hard tooth tissue resulting acid demineralization of hard tooth tissue resulting in the formation of a cavity.in the formation of a cavity.

Theories of caries:Theories of caries:- Worm theoryWorm theory- Vital theory (1700s)Vital theory (1700s)- Chemo-parasitic theory (W.D Miller 1890)Chemo-parasitic theory (W.D Miller 1890)


Types of caries lesions:Types of caries lesions:

1.1. Pit and fissure cariesPit and fissure caries

2.2. Smooth surface cariesSmooth surface caries

3.3. Root surface cariesRoot surface caries

4.4. Secondary (recurrent) cariesSecondary (recurrent) caries


Mature enamel is composed of 95% inorganic Mature enamel is composed of 95% inorganic (minerals) and 5% organic material and water (minerals) and 5% organic material and water (Fig 3-5).(Fig 3-5).

Enamel of a newly erupted tooth is not fully Enamel of a newly erupted tooth is not fully mineralized. Therefore, newly erupted teeth are mineralized. Therefore, newly erupted teeth are more susceptible for caries than teeth that have more susceptible for caries than teeth that have been present in the mouth for some time. been present in the mouth for some time.


Stages of dental caries:Stages of dental caries:

1.1. Incipient lesionIncipient lesion

2.2. Lesion extending to or beyond DE junctionLesion extending to or beyond DE junction

3.3. FrankFrank lesion with cavitation lesion with cavitation In theory, caries extending to dentin with intact In theory, caries extending to dentin with intact

enamel surface can be slowly be remineralized enamel surface can be slowly be remineralized (ten Cate, 2001)(ten Cate, 2001)


Incipient lesionIncipient lesion

- - Characterized by white spot on the enamel Characterized by white spot on the enamel surface.surface.

- In fissure caries, usually occurs bilaterally on the In fissure caries, usually occurs bilaterally on the two surfaces at the orifice of the fissure and two surfaces at the orifice of the fissure and eventually coalesces at the baseeventually coalesces at the base

- The surface enamel is usually intact and lesion is The surface enamel is usually intact and lesion is located subsurfacelocated subsurface


Progression of caries depends onProgression of caries depends on

1.1. Ions concentrationIons concentration

2.2. pHpH

3.3. Salivary flowSalivary flow

4.4. Buffering actionBuffering action Plaque acids dissolve first the magnesium and Plaque acids dissolve first the magnesium and

carbonate ions and followed later by less soluble carbonate ions and followed later by less soluble ions such as calcium and phosphate ions. ions such as calcium and phosphate ions.


For caries to develop, acidogenic bacteria must be For caries to develop, acidogenic bacteria must be present and a means must exist to prevent the present and a means must exist to prevent the acid from being washed away.acid from being washed away.

Germ-free animals do not develop caries even Germ-free animals do not develop caries even when fed cariogenic diet (Orland et al 1954)when fed cariogenic diet (Orland et al 1954)

Mutans streptococci and lactobacilli are the two Mutans streptococci and lactobacilli are the two major acidogenic bacteriamajor acidogenic bacteria


Mutans streptococci:Mutans streptococci:1.1. Ability to adhere to tooth surfacesAbility to adhere to tooth surfaces2.2. Production of abundant insoluble extracellular Production of abundant insoluble extracellular

polysaccharides (glucan)polysaccharides (glucan)3.3. Production of intracellular polysaccharidesProduction of intracellular polysaccharides4.4. Rapid production of lactic acidRapid production of lactic acid5.5. Acid toleranceAcid tolerance Damage observed in carious lesion is due to lactic Damage observed in carious lesion is due to lactic

acid, although other acids are present within the acid, although other acids are present within the plaqueplaque


Lactobacilli:Lactobacilli:- LB does not play a major role in carious lesion LB does not play a major role in carious lesion

initiation, but important in the progression of initiation, but important in the progression of lesionlesion

- With established low pH, the number of LB With established low pH, the number of LB increases and the number of MS decreases.increases and the number of MS decreases.


Ecology of dental caries:Ecology of dental caries:- Before teeth eruption the number of MS is very Before teeth eruption the number of MS is very

lowlow- The source of infection of infant by MS is from The source of infection of infant by MS is from

caregiver (usually the mother) by mouth-to-caregiver (usually the mother) by mouth-to-mouth transmission via kissing or sharing spoon mouth transmission via kissing or sharing spoon during feedingduring feeding


Root Caries:Root Caries:- Individuals are living longer and therefore Individuals are living longer and therefore

retained teeth may develop root caries associated retained teeth may develop root caries associated with gingival recessionwith gingival recession

- Most seniors are consuming medications known Most seniors are consuming medications known to reduce the salivary flow and therefore increase to reduce the salivary flow and therefore increase the risk of root cariesthe risk of root caries

- Prevention of root caries can be achieved by Prevention of root caries can be achieved by preventing periodontal disease preventing periodontal disease


Stephan Curve:Stephan Curve:- Named after Dr. Robert StephanNamed after Dr. Robert Stephan- Showed the effect of eating or drinking different Showed the effect of eating or drinking different

foods and beverages on plaque pH (Fig 3-9)foods and beverages on plaque pH (Fig 3-9)


Demineralization and remineralization:Demineralization and remineralization:

- Long term exposure of teeth to low concentration of fluoride Long term exposure of teeth to low concentration of fluoride (as in fluoridated water) results in gradual incorporation of (as in fluoridated water) results in gradual incorporation of fluoride into existing hydroxyapatite (HAP) crystals to form fluoride into existing hydroxyapatite (HAP) crystals to form fluorhydroxyapatite (FHA) that is more resistant to acid fluorhydroxyapatite (FHA) that is more resistant to acid damage. This form is known to be firmly bound fluoridedamage. This form is known to be firmly bound fluoride

- Topical application of higher concentration of fluoride to the Topical application of higher concentration of fluoride to the tooth surface results in the formation of surface globules of tooth surface results in the formation of surface globules of calcium fluoride that is subsequently covered with phosphate calcium fluoride that is subsequently covered with phosphate and proteins from saliva rendering these globules more and proteins from saliva rendering these globules more insoluble. This form is known to be loosely bound fluorideinsoluble. This form is known to be loosely bound fluoride



- Following an attack by the plaque acids, the CaF2 dissolve Following an attack by the plaque acids, the CaF2 dissolve first followed by HAP and finally FHA.first followed by HAP and finally FHA.

- With the increase of ions concentration, the crystals With the increase of ions concentration, the crystals dissolution slows.dissolution slows.

- New HAP and FHA reform to fill the defect with most of New HAP and FHA reform to fill the defect with most of fluoride ions coming from CaF2 and newly adsorb CaF2fluoride ions coming from CaF2 and newly adsorb CaF2



- Use of fluoride varnish:Use of fluoride varnish:

Some studies have shown that biannual application of Some studies have shown that biannual application of fluoride varnish may stop the activity of 81% of active fluoride varnish may stop the activity of 81% of active enamel caries on primary teethenamel caries on primary teeth

Periodontal DiseasePeriodontal Disease

Definition: periodontal disease is a Definition: periodontal disease is a dental plaque-induced disease dental plaque-induced disease affecting the supporting tissue of affecting the supporting tissue of the tooth (periodontium). It ranges the tooth (periodontium). It ranges from mild reversible form from mild reversible form (gingivitis) to a more severe and (gingivitis) to a more severe and irreversible form (periodontitis). irreversible form (periodontitis).


Structures of periodontiumStructures of periodontium


Gingivitis: An inflammation process of the Gingivitis: An inflammation process of the gingiva in which the junctional epithelium, gingiva in which the junctional epithelium, although altered by the disease, remains although altered by the disease, remains attached to the tooth at its original level. attached to the tooth at its original level.

Periodontitis: An inflammation condition of the Periodontitis: An inflammation condition of the gingival tissues, characterized by loss of gingival tissues, characterized by loss of attachment of the periodontal ligament and the attachment of the periodontal ligament and the bony support of the toothbony support of the tooth


Factors affecting the PD:Factors affecting the PD:

1.1. Bacterial plaqueBacterial plaque

2.2. Patient’s medical conditionsPatient’s medical conditions

3.3. Patient’s environmental factorsPatient’s environmental factors

4.4. Patient’s genetic backgroundPatient’s genetic background


Development of gingivitisDevelopment of gingivitis- Gingivitis can be observed 9-21 days after cessation Gingivitis can be observed 9-21 days after cessation

of oral hygiene measures in a healthy mouthof oral hygiene measures in a healthy mouth

- The degree of gingival inflammation depends on the The degree of gingival inflammation depends on the amount of plaque accumulationamount of plaque accumulation


Development of gingivitisDevelopment of gingivitis

- Damaged caused by gingivitis can be reversed by Damaged caused by gingivitis can be reversed by practicing removing the cause of disease, i.e., dental practicing removing the cause of disease, i.e., dental plaque and calculus plaque and calculus

- Systemic conditions such as pregnancy or hormonal Systemic conditions such as pregnancy or hormonal imbalance may exaggerate gingival tissue response imbalance may exaggerate gingival tissue response to bacterial presence in the dental plaqueto bacterial presence in the dental plaque

- Similar reactions maybe also seen with certain Similar reactions maybe also seen with certain drugsdrugs


Development of gingivitisDevelopment of gingivitis

- Clinical changes observed with gingivitis:Clinical changes observed with gingivitis:

1.1. Alterations in color (pink red)Alterations in color (pink red)

2.2. Knife-edge margin of free gingiva rolledKnife-edge margin of free gingiva rolled

3.3. Gingiva firm consistency Spongy consistency Gingiva firm consistency Spongy consistency

4.4. Bleeding maybe observedBleeding maybe observed


Periodontal MicrofloraPeriodontal Microflora- Periodontal disease process is Periodontal disease process is

understood in the frame of two understood in the frame of two Hypotheses:Hypotheses:

1.1. Non-specific plaque HypothesisNon-specific plaque Hypothesis

2.2. Specific plaque HypothesisSpecific plaque Hypothesis


All periodontitis is preceded by gingivitis All periodontitis is preceded by gingivitis progresses, but not all untreated gingivitis progresses, but not all untreated gingivitis progresses to periodontitisprogresses to periodontitis

The development of periodontal pocket The development of periodontal pocket (pathological) implies that there is apical (pathological) implies that there is apical migration of junctional epitheliummigration of junctional epithelium


Prevention of periodontal diseasePrevention of periodontal disease1.1. Mechanical plaque control:Mechanical plaque control:- Regular toothbrushingRegular toothbrushing- Routine use of dental flossRoutine use of dental floss2.2. Chemical plaque control:Chemical plaque control:- Use of mouth rinses such as chlorhexidine Use of mouth rinses such as chlorhexidine - Topical fluoride maybe used to prevent root cariesTopical fluoride maybe used to prevent root caries3.3. Removal of local factors such as calculus (via Removal of local factors such as calculus (via

scaling) or restorations with defective margin (i.e. scaling) or restorations with defective margin (i.e. new restorations)new restorations)

Tooth-Brushes and Tooth Tooth-Brushes and Tooth Brushing MethodsBrushing Methods

Summary of Lecture # 2 October 3, 2007 Abdullah S. Al-Swuailem BDS, MS, MPH, Dr PH.

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Transcript of Summary of Lecture # 2 October 3, 2007 Abdullah S. Al-Swuailem BDS, MS, MPH, Dr PH.