Mother-child transmission of mutans streptococci

The window of infectivity for mutans streptococci

The earlier the mutans streptococci are colonized, the higher is the risk for caries

Transmission of mutans streptococci The mother (infecting person) has high salivary mutans streptococci counts Several daily saliva contacts between the child and the mother must take place

Methods to prevent the acquisition of mutans streptococci Information on mother-child transmission of ms, advice on diet and oral hygiene Chemical methods (chlorhexidine) Xylitol

Mother-child study Eva Söderling and Pauli Isokangas Institute of Dentistry, Turku Ylivieska Health Centre, Ylivieska

Subjects At baseline 195 mothers with high salivary mutans streptococci counts (60% of all mothers) 2-year examination: 169 mother-child pairs 6-year examination: 147 children

Study groups Xylitol group: xylitol chewing gum 4 times a day Fluoride (F; control) group: fluoride varnish (2.26%) treatments 2 times a year Chlorhexidine (CHX) group: CHX varnish (40%) treatments 2 times a year All interventions discontinued when the child was 2 years old

Xylitol chewing gum

Only the mothers used xylitol/were treated with varnish; no additional treatments to children

Results

Mutans streptococci of the mothers: High salivary mutans streptococci counts in all groups throughout the study No differences between the study groups Pregnancy0.512 Age o f c h ild (years) F CH X Xyl IogCF/ml

Mutans streptococci of the 2-year- old children (Söderling et al., JDR 2000) The child’s risk of having mutans streptococci colonization in the dentition was 5-fold in the F group and 3-fold in the CHX group as compared to the Xylitol group

Caries occurence in children At the age of 5 years the need of restorative treatment was 71-75% lower in the Xylitol group as compared to the F and CHX groups The occurence of caries and early mutans streptococci colonization were in agreement

Prevention of Maternal- Infant Transmission of Caries A Randomized Clinical Trial

Investigator Affiliation University of Washington Schools of Dentistry, Medicine and Public Health Departments of Dental Public Health Sciences, Pediatrics, Health Services, Pediatric Dentistry

Background Rates of early childhood caries 4.5 fold higher among Alaska Natives High rates of caries likely related to: –high load of oral bacteria that cause caries S. mutans, S. sobrinus early acquisition –decreased fluoride exposure – large amounts of refined sugar in diet –poor oral hygiene

Specific Aim To determine if the infants of pregnant mothers who use CHX mouth rinses for two weeks, followed by xylitol gum use for two years, experience less dental decay compared to infants of mothers who do not use these interventions

Methods: Design Randomized controlled trial 2 arms: intervention vs. control double-blinded

Yukon-Kuskokwim Delta

Subjects Enroll: Pregnant mothers at weeks of gestation Track outcomes: –Mothers –Liveborn children who are offspring of enrollees Exclude: infants born in Anchorage, infants with congenital anomalies

Intervention: Both Groups Dental hygiene and exam Restoration of caries and extractions as necessary Dental and dietary counseling/education Toothbrushes and toothpaste

Intervention Group Only Chlorhexidine rinses, twice a day for two weeks; starts at enrollment Xylitol gum 5.1 grams per day (3x/day) for two years

Outcome Assessment Outcomes of interest –caries among infants at 1 and 2 years of age all enrolled children deft –S. mutans counts for mothers and infants at same time intervals for subset (n=30) only

Data Collection Baseline: –maternal dental exam –maternal gingival culture (subset) –maternal oral health questionnaire T 1 (infant age= one year) –oral health questionnaire –infant dental exam –infant and maternal gingival cultures (subset)

Data Collection T 2 (infant age=2 years) –oral health questionnaire –infant dental exam –infant and maternal gingival cultures (subset)

Analysis Compare rates of caries between intervention and control groups –(unit of analysis: child or teeth) Compare S. mutans counts between groups Control for confounding factors, if present

Potential limitations Compliance with intervention Blinding Misclassification of exposure –e.g. control mom uses intervention –mother doesn’t rear child Intensification of exposure –e.g. whole family uses gum

Sample Size Estimates N=375 births/year –Exclude 25% born in Anchorage –Assume 10% refusal rate –Enroll approximately 125 in each group –Assume 80% follow-up at two years –Need about 200 at final follow-up About 90% power to detect a 50% reduction in the intervention group

Future studies…

Xylitol administration with a slow-release pacifier for AOM and ECC?

Diet and dental caries

Subsidizing toothpaste, introducing xylitol snacks

What is most impressive about xylitol is its safety

Effectively addressing caries will require new and better tools for public health

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