Faculty Bibliography

We previously reported that a Streptococcus mutans enriched-glucosytransferase (E-GTF) preparation induces an immune response following intranasal, but not tonsillar, immunization of humans. In this study, we determined whether intranasal immunization of these subjects 2 years later resulted in augmented immune responses compared to those seen in control subjects. Subjects previously immunized via the intranasal (IN, n = 7) or tonsillar (IT, n = 7) route and control (n = 12) subjects were immunized via the intranasal route with E-GTF. Nasal wash, saliva, and serum were collected before immunization and then weekly for 3 months after immunization. Significant (P < 0.05) mucosal and serum immunoglobulin A (IgA) anti-E-GTF responses were observed in all three groups. Nasal and serum IgA anti-E-GTF responses were significantly higher (P < 0.05) in the IN group. The salivary responses in the three groups were, in general, similar. These results indicate that intranasal immunization primes the immune system for a localized secondary response to S. mutans antigens

PURPOSE: The purpose of this study was to investigate the relationship between: (1) children's caries score (dmft, DMFT) at the time of sealant placement; and (2) 'success' (measured as being caries-free) of that tooth at follow-up visits. METHODS: An existing database of over 38,000 sealants (10,038 children) placed between 1997 and 2002 by the Jefferson County Health Department's Community Based Sealant Program, Birmingham, Ala, was used in the analysis. Only children returning for followup visits after the initial placement of the sealants were included in this study, resulting in 6,452 sealants (2,097 children). Logistic regression analysis was performed to determine the differences in sealant success between children with a dmft score of 0 vs a dmft score of >0 at baseline, and a DMFT score of 0 vs a DMFT score of >0 at baseline. RESULTS: In the permanent and primary dentitions, those who had no caries at the time of sealant placement (dmft/DMFT=0) had a significantly higher success of sealants during years 1 to 5 compared to those with a caries score of greater than 0 (dmft/DMFT>0; P<.023, P<.002, respectively). CONCLUSION: Children with previous caries experience may be at a higher risk for sealant 'failure' (measured as caries on a tooth surface previously sealed) after 1 year and, therefore, may require more diligent sealant maintenance

AIM: To determine the incidence of ProFile nickel-titanium rotary instrument fracture in an endodontic laboratory simulation. METHODOLOGY: Three hundred and sixty dental students used 2880 ProFile nickel-titanium rotary instruments to prepare 1440 simulated root canals in 720 plastic teeth, and another 2880 ProFile nickel-titanium rotary instruments to prepare 1440 natural root canals in 720 extracted teeth. A standardized crown-down rotary instrumentation technique was used, which included measures to prevent fracture. Rotary instrument fracture was monitored during and after completion of the laboratory simulation exercises to determine the incidence of fracture. When fracture occurred, data were collected concerning the size of the instrument, the length of the instrument fragment, the location of the fragment in the canal and the curvature of the canal in which the instrument fractured. RESULTS: The incidence of instrument fracture was 0.41% in plastic simulated canals and 0.31% in natural root canals. The overall incidence of instrument fracture was 0.36%. Of the instruments that fractured 67% were size 25, 0.04 taper; and 81% of the fragments were located in the apical third of the canal. The mean, median and mode of the fragment lengths were all 3 mm. CONCLUSIONS: The low overall incidence of fracture in this study suggests that ProFile rotary instruments are safe for use by dental students in laboratory simulations and that if preventive measures are taken the incidence of instrument fracture can be minimized

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.

By definition, dental caries is an infectious and transmissible disease because it is caused by bacteria colonizing the tooth surfaces. Unlike most infectious diseases affecting humans, caries is the result of an imbalance of the indigenous oral biota rather than a nonindigenous, exogenous pathogen. The introduction of refined sugar into modern society's diet has tipped the balance from health to disease. New insight into the natural history of the leading cariogenic bacteria, the mutans streptococci, may contribute ways to control or prevent this infectious disease. Here, we use the host-parasite model as a platform for viewing the pathogenicity of the caries process in contrast to other infectious diseases.

S. mutans plays a key role in dental caries. The extent to which perinatal events influence the acquisition of S. mutans is unclear. We hypothesized that several maternal factors, including the mode of delivery, influence the initial acquisition of S. mutans in infants. A prospective cohort study was conducted in 156 mother-infant pairs. The study found that maternal gestational age (p = 0.04), S. mutans level (p = 0.02), caries score (p = 0.02), sexually transmitted disease (STD) infection experience (p = 0.01), and family income (p = 0.03) had significant effects on the acquisition of S. mutans. Among infants who became infected, those delivered by Caesarean section acquired S. mutans 11.7 mos earlier than did vaginally delivered infants (p = 0.038). C-section infants harbored a single genotype of S. mutans that was identical to that of their mothers (100% fidelity). Analysis of the data demonstrated the possible perinatal influences on infants' acquisition of a member of the cariogenic microbiota, and its potential effect on caries outcome.