Faculty Bibliography

BACKGROUND: Gravida's poor periodontal health is emerging as a modifiable independent risk factor for preterm delivery and low birth weight. METHODS: To test the hypothesis that oral bacteria other than periodontal pathogens are also associated with pregnancy outcomes, specific oral bacterial levels measured during pregnancy were evaluated in relation to gestational age and birth weight while controlling for demographic, medical, and dental variables. The study population consisted of 297 predominantly African- American women who were pregnant for the first time. The salivary bacterial levels evaluated were Streptococcus mutans, Streptococcus sobrinus, Streptococcus sanguinus, Lactobacillus acidophilus, Lactobacillus casei, Actinomyces naeslundii genospecies (gsp) 1 and 2, total streptococci, and total cultivable organisms. RESULTS: For 1 unit increase in log(10) A. naeslundii gsp 2 levels, there was a 60 gm decrease in birth weight (beta = -59.7 g; SE = 29.1; P = 0.04), and a 0.17 week decrease in gestational age (beta = -0.17 wk; SE = 0.09; P = 0.05). In contrast, per 1 unit increase in log(10) L. casei levels, there was a 42 gm increase in birth weight (beta = 42.2 g; SE = 19.3; P = 0.03), and a 0.13 week increase in gestational age (beta = 0.13 week; SE = 0.06; P = 0.04). CONCLUSIONS: We conclude that other oral bacterial species can also be related to pregnancy outcomes in addition to previously reported periodontal pathogens. These organism levels may not only predict poor pregnancy outcomes, but also be used as modifiable risk factors in reducing prematurity and low birth weight.

The objective of the present study was to design a PCR-generated DNA probe and determine the specificity of the probe for the identification of clinical isolates of Streptococcus sanguinis. To do this, we examined over 200 arbitrarily primed PCR (AP-PCR) amplicon patterns obtained with DNA from clinical isolates of S. sanguinis. A 1.6-kb DNA amplicon that was common to all AP-PCR profiles was extracted from agarose gels and then cloned and sequenced. A search for a similar sequence in the GenBank database with the BLASTN program revealed that the 1.6-kb DNA fragment comprised an intergenic region between two housekeeping genes, uncC (proton-translocating ATPase) and murA (UDP-N-acetylglucosamine enolpyruvyl transferase). Three digoxigenin-labeled DNA probes were synthesized on the basis of the sequence of the 1.6-kb fragment: the sequence of probe SSA-1 contained the proton-translocating ATPase (uncC) and the entire intergenic region, the sequence of probe SSA-2 contained only the intergenic region, and the sequence of probe SSA-3 contained an internal region of the murA gene. Dot blot hybridization showed that the three probes displayed signals for hybridization to both S. sanguinis strain ATCC 10556 and the S. sanguinis clinical isolates. Probe SSA-1, however, hybridized to DNA from S. oralis and S. mitis. Probe SSA-3 hybridized to DNA from S. gordonii, S. mitis, S. oralis, S. parasanguinis, and S. vestibularis. The probe SSA-2-specific intergenic region appeared to be specific for S. sanguinis. The results from this study suggest that probe SSA-2 may serve as a species-specific DNA probe for the identification of clinical isolates of S. sanguinis.

In the current literature database, information on microbiological attributes to caries outcomes in African American populations is limited and scattered. Few reports have discussed MS infection and transmission from African American mothers to their children. During the past few years, the research group at the University of Alabama at Birmingham and the Jefferson County Pubic Health Department have done a series of extensive studies to systematically investigate the prevalence of MS colonization, the time of initial MS infection as defined as "the window of infectivity," the source of MS transmission as defined as "the fidelity of transmission, and the chemotherapeutic management of MS transmission and caries prevention. The objective of this report was to summarize the main significant findings generated during a period of 15 years of study. One limitation of the studies outlined in this article is that the research populations were predominately African American families. The inclusion of white and other minorities would make the conclusions more generalizable to the US population as a whole. Nevertheless, the information presented in this report can serve as baseline knowledge for future studies of caries etiology in African American and other ethnic populations.

Actinomyces naeslundii genospecies 2 (gsp-2) are members of the autochthonous oral flora. Chromosomal DNA fingerprinting (CDF) with SmaI revealed extensive genetic diversity among A. naeslundii gsp-2 strains within individual mothers and children. There was a low prevalence of genotype match among A. naeslundii gsp-2 strains between all mother and child pairs.

OBJECTIVE: To study whether the caries status of the primary dentition correlated with status of the permanent in the same cohort over an eight-year period. To determine whether the caries status of the primary dentition can be used to predict caries in the permanent dentition. METHODS: A total of 362 children, 3 - 4 years old in the baseline study in 1992 were re-examined in 2000 based on WHO criteria and methods. RESULTS: Statistically significant associations were observed between the caries prevalence in primary and permanent teeth (P < 0.01) and between DMFT(s) and dmft(s) (P < 0.01). Children who had caries in the primary teeth were nearly three times more likely to have caries in the permanent teeth (RR = 2.6,95% CI = 1.4 - 4.7, P < 0.001). The highest sensitivity (93.9%) for prediction caries in the permanent dentition was found in caries presence on any of the eight primary molars, for which the relative ratio was 3.3 (95% CI = 1.8 - 6.1, P < 0.001) and the positive prediction value was 85.4%. CONCLUSION: The study determinate clearly that caries status in the primary teeth can be used as a risk indicator for predicting caries in the permanent dentition

In a randomized clinical trial, we evaluated the effect of a 10% chlorhexidine varnish (Chlorzoin) on the mother-child transmission of Streptococcus mutans and on subsequent caries experience. Chlorhexidine (n = 38) or a placebo varnish (n = 37) was applied to the dentitions of 75 mothers at a time when their first babies were about 6 months old (approximate time of first tooth emergence). Three more applications at weekly intervals and subsequent applications at 6-month intervals followed the initial application. The mother-child pairs were followed up until the child's fourth birthday. Maternal salivary S. mutans levels in the treatment group remained significantly lower (p < 0.05) compared to the control group up to 12 months after the initial application. However, this intervention did not significantly alter the S. mutans colonization in children or the caries increment in either the mother or the child.