Probiotics and dental caries risk

Dr. Hakan ÇolakDDS. PhD

Department of Restorative Dentistry

Introduction

• The Food and Agriculture Organization (FAO)/World Health Organization (WHO) have defined probiotics as “live micro-organisms, which when administered in adequate amounts, confer a health benefit to the host.”

Introduction

• Probiotics are used in the prevention and treatment of infectious diseases and allergies.

• In some countries probiotics are recommended for infants because of their long-term enhancement of the immune responses of children

Introduction

• Probiotics are mainly ingested orally, and the gastrointestinal tract is thus the primary target organ for probiotic microorganisms.

• However, when ingested in the form of, for example, tablets, chewing gums, cheese, and milk, the oral cavity is exposed to the probiotics.

Introduction

• The probiotic species most often investigated and widely used in foods are lactobacilli and bifidobacteria.

• This presentation focuses mainly on these genera even though other microorganisms are also used as probiotics

Introduction

Mechanisms of Action Of Oral Probiotics

DIRECT INTERACTIONS IN DENTAL PLAQUE

Disrupt binding of oral microorganisms to proteins

Interrupt bacteria-to-bacteria attachments

Compete with oral microorganisms and their substrates

Produce antimicrobial substances

INDIRECT PROBIOTIC ACTIONS IN THE ORAL CAVITY

Modulating systemic immune function

Effect on local immunity

Effect on non-immunologic defense mechanisms

Regulation of mucosal permeability

Colonization by less pathogenic species

PROBIOTICS

ORAL BIOFILM AND MICROFLORA

Caries-related mechanisms of probiotic activity

• Lactobacilli and bifidobacteria are both acidogenic and aciduric.

• Some lactobacilli and bifidobacteria, including L. Rhamnosus GG and B. lactisBB-12, do not ferment sucrose (Haukioja et al. 2008).

Caries-related mechanisms of probiotic activity

• The low pH generated by most probiotics is also crucial for their antimicrobial actions. – Several studies have demonstrated that probiotic

lactobacilli may inhibit caries-associated microorganisms via antimicrobial substances active at a low pH.

• The growth inhibition of S. mutans in vitro has been attributed to the generation of a low pH either via organic acid production and/or production of bacteriocins or metabolites active at a low pH (Simark-Mattsson et al., 2009)

Caries-related mechanisms of probiotic activity

• The adhesion capacity and persistence on the oral mucosa and teeth – an important property of probiotics from an oral

health point of view. – In vitro studies have demonstrated that probiotic

lactobacilli show varying degrees of adhesion to saliva-coated hydroxyapatite surfaces

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Caries-related mechanisms of probiotic activity

• interactions between oral microorganisms and probiotics– Probiotics may modify the protein composition of

the pellicle and specifically prevent adhesion of other bacteria

Probiotics and counts of mutans streptococci

• In adults, even high counts of MS in the plaque/saliva do not necessarily mean an increased caries risk. However, decreasing MS without affecting the “normal flora” should improve the microbiological composition of the plaque and make it less virulent

• In adults via straws, tablets, medical devices, milk, and chewing gums, all studies resulting in a decrease of MS counts

Probiotics and counts of mutans streptococci

• In some countries probiotics are recommended for infants. Thus, a major concern is the effect the administration may have on the colonization of erupting teeth and the future dental health of the child.

Probiotics and caries occurrence

• Probiotics, mostly lactobacilli or bifidobacteria, are aciduric and acidogenic microorganisms. Such bacteria are usually connected with caries occurrence, not its prevention.

• So far the few studies on probiotics and caries occurrence suggest that probiotics could rather promote dental health than be a hazard to it.

• In a Finnish study, 594 children ages 1 to 6 years old attending a day-care center, received L. rhamnosusGG-containing milk for 7 months. The milk use reduced the caries risk significantly in the 3- to 4-year-old children

• Swedish study, – 248 preschool children ages 1 to 5 years -old – received either a control milk or a test milk

supplemented with both fluoride and L. Rhamnosus LB21 for 21 months (Stecksen-Blicks et al. 2009).

– Caries occurrence decreased significantly in the test group