Comparison of chairside microbiological screening systems and conventional selective media in children with and without visible dental caries.

PURPOSE: The purpose of this study was to compare the results of commercial chairside microbial tests (CT) and conventional selective media (GS, gold standards) for mutans streptococci (MS) and lactobacilli (LB) using oral specimens from young children with and without visible dental caries. METHODS: Using cotton swabs to collect oral microbial specimens from children 10 to 36 months old, microbial counts of CT and GS were compared with caries experience of the subjects. Contamination levels by non-MS or non-LB isolates on CT and GS were also determined. The CT employed were: (1) CRT bacteria for MS and LB; (2) CarioCheck Plus for MS and LB; and (3) Dentocult SM and Mucount for MS. RESULTS: All CT and GS for MS represented caries status of the participants (P<.001, Fisher exact test; P<.015 linear regression), whereas only GS for LB showed significant association with caries status (P<.001, Fisher exact test; P<.001, linear regression). Non-MS or non-LB isolates were observed on most media, and CT usually exhibited higher contaminant levels than GS. Dentocult SM and Mucount did not harbor contaminants. CONCLUSIONS: Despite contamination, CT and GS for MS and GS for LB exhibited satisfactory outcomes based on cross-sectional caries experience of infants and toddlers.

Evaluation of microbiological screening systems using dental plaque specimens from young children aged 6-36 months.

Using cotton swab specimens of dental plaque from children aged 6-36 months, four commercial chairside tests for oral bacteria were evaluated by comparison with conventional selective culture: mitis salivarius kanamycin bacitracin agar for mutans streptococci and Rogosa SL agar for lactobacilli. Representative colonies of all isolates were identified by commercial identification kits. According to qualitative evaluations, all chairside tests for mutans streptococci were effective in our population. Those for lactobacilli were not as effective, due mainly to a high recovery of yeast contaminants.

Microbiological screening for cariogenic bacteria in children 9 to 36 months of age.

PURPOSE: The objective of this study was to evaluate sampling methods for recovery of mutans streptococci (MS) and lactobacilli (LB) in children 9 to 36 months of age. METHODS: Tongue and plaque specimens collected on cotton swabs and stimulated saliva were diluted and plated on selective and nonselective media. Tongue specimens on a swab and mouth mirror were inoculated directly on selective agar media (MS only). Sampling methods were compared by frequency of recovery of MS or LB, correlation of microbial counts with dmfs scores, and potential of specific microbial counts to predict caries presence or absence. RESULTS: The mean dmfs score of 87 subjects was 6.3; 48 subjects were caries free. Levels of MS and LB were consistently higher in plaque than in other sampling techniques (P<.001), and frequencies of recovery of MS were highest in plaque (P<.041) and tongue (P<.006). Frequency of LB recovery did not differ significantly between sampling methods. Counts of MS or LB in total subjects and subjects aged 9 to 24 months correlated positively with dmfs scores (P<.028). Threshold levels of MS which were predictive of presence of caries were: (1) plaque=>2x10(5); (2) tongue=>10(4); (3) saliva=>10(5); (4) mirror=>50; and (5) swab=>50. Comparable levels of LB were: plaque, >10(3); tongue, >10(2) and saliva, >10(3). Specificities associated with these predictions were higher than sensitivities for all sampling methods. CONCLUSIONS: (1) All sampling methods were adequate for microbial risk assessment tests in children under 3 years of age; (2) MS was a stronger indicator of caries status than LB.

Candida albicans colonization of surface-sealed interim soft liners.

PURPOSE: This in-vivo investigation evaluated the effect of 2 denture sealer agents on the microbial colonization of a newly placed soft interim denture liner during a period of 14 days. MATERIALS AND METHODS: An interim soft denture liner (Coe-Soft; GC America, Alsip, IL) was coated with 2 different denture surface sealants (Palaseal [Heraeus Kulzer, Irvine, CA] and Mono-Poly [Plastodent, New York, NY]). Three rectangular wells of 1 cm wide x 2 cm long x 2 mm deep were placed in the intaglio of 10 maxillary complete dentures and filled with the soft liner material. The soft liner surface was treated with Palaseal (first well) and Mono-Poly (second well), and the unsealed (third well) was used as a control. These were exposed to the oral cavity for 14 days. The effect the sealant had in the prevention of Candidal colonization in vivo of the soft liner material was evaluated. Microbiological specimens were recovered from all samples and cultivated. Microbiological data from the control and 2-test samples in each denture were tabulated, and statistical analyses were performed. RESULTS: This investigation showed clear differences (p <.001) between the sealed and unsealed soft liners. The sealed material showed significantly less colonization by yeast and bacteria. Intercomparison of the surface denture sealers, Palaseal versus Mono-Poly, showed no statistically significant differences (p < .005) in total yeast or bacterial colonization. CONCLUSION: Coating of Coe-Soft denture liner with either Palaseal or Mono-Poly significantly decreased yeast and bacterial colonization. .

Oral malodor in children and volatile sulfur compound-producing bacteria in saliva: preliminary microbiological investigation.

PURPOSE: This study examined and compared levels of salivary bacteria which produced volatile sulfur compounds (VSC) in young children with and without oral malodor. METHODS: Clinic populations of children aged two to seven years, whose parents presented with an unsolicited major complaint of oral malodor in their child (OM+), or aged-matched controls in whom oral malodor was not detected by parents (OM-), were investigated. Saliva specimens were cultured anaerobically on media that differentiated VSC+ bacteria. These were quantified and identified. Levels in OM+ and OM- children were compared and statistically analyzed. RESULTS: OM+ children harbored significantly higher levels of VSC+ isolates in saliva than OM- children (OM+ = 44% of total viable counts, TVC; OM- = 24% of TVC; P = 0.0083). Types of recovered bacterial species did not differ in the two groups, but levels of Prevotella oralis were significantly higher in OM+ children (P = 0.0001). Veillonella species followed by P. oralis were the predominant VSC+ isolates recovered in both populations. CONCLUSIONS: VSC+ salivary bacteria may differ both in type and quantity in young children with and without parent-perceived oral malodor.

Subtraction radiography of dentinal caries-like lesions induced in vitro by cariogenic bacteria.

PURPOSE: The objective of this project was to develop an in vitro model system for investigations of dentinal caries. METHODS: Five extracted primary molar teeth with circular cavity preparations to the depth of the dentinoenamel junction were mounted individually in cold-cure acrylic bases constructed to fit a positioning jig in a Schick-Technologies digital radiographic imaging apparatus. The mounted teeth (MT) were incubated with pure cultures of Streptococcus mutans for 7 days and Lactobacillus casei for 38 days. At baseline and on day 23 and 45, four digital radiographs of each MT were made. Subtraction radiography was performed and analyzed using custom interactive software. RESULTS: Lesions progressed roughly halfway through the dentin in all teeth at 23 days and approximated the pulp chambers at 45 days of incubation. Images resulting from subtraction procedures clearly revealed incremental caries progression which could be quantitated. CONCLUSION: The model may be useful for screening cariostatic dental materials or treatments and investigating microbial mechanisms in dentinal caries.

Inhibition of pure cultures of oral bacteria by root canal filling materials.

This study compared the antimicrobial effectiveness of nine dental materials and a negative control agent against 21 strains or species of bacteria using an agar diffusion assay. The materials were: 1. Camphorated parachlorophenol mixed with calcium hydroxide (CPC + Ca(OH)2). 2. CPC mixed with zinc oxide (CPC + ZnO). 3. Formocresol mixed with zinc oxide and eugenol (FC + ZOE). 4. Chlorhexidine mixed with ZOE (CHX + ZOE). 5. Kri paste. 6. ZOE. 7. Zinc oxide mixed with sterile water (ZnO + H2O). 8. Calcium hydroxide mixed with sterile water (Ca(OH)2 + H2O). 9. Vitapex. 10. Vaseline (control). The test bacteria represented species commonly isolated from nonvital primary and permanent tooth root canals. The antimicrobial effectiveness of the materials was divided into five groups based on the diameters of the zones of inhibition against all test bacteria and distribution of the data. All materials except Vaseline showed antimicrobial activity against some of the 21 organisms. Generally, all materials inhibited gram-negative anaerobic bacteria more effectively than aerotolerant gram-negative or gram-positive bacteria. Materials containing CPC or FC (except Kri paste) produced strong or medium strong inhibition against most bacteria. CHX + ZOE, Kri paste, ZnO + H2O, and ZOE inhibited all or most bacteria, but to lesser extent than CPC + Ca(OH)2, CPC + ZnO, or FC + ZOE. Ca(OH)2 + H2O, Vitapex, and Vaseline generally were nonihibitory. The findings should allow a comparative evaluation of antimicrobial effectiveness to be made of materials commonly used in pulpectomy procedures with primary teeth.

Development and evaluation of a selective and differential medium for the primary isolation of Peptostreptococcus micros.

Peptostreptococcus micros, an anaerobic gram-positive coccus, has been associated with periodontal and endodontic lesions, including those refractory to treatment, as well as many human polymicrobial infections in other body locations. A selective and differential medium for the primary isolation of P. micros was developed and evaluated. Columbia CNA agar, a selective medium for gram-positive cocci, was supplemented with glutathione and lead acetate (P. micros medium: PMM). P. micros has a characteristic of rapidly utilizing the reduced form of glutathione to form hydrogen sulfide, which reacts with lead acetate producing a black precipitate in the medium. When grown on PMM, P. micros can be easily identified by its typical colonial morphology and the presence of a black precipitate directly under the colony. PMM was compared for the growth of P. micros with phenylethyl alcohol agar (PEA) and Columbia base medium (CBM) with 80 strains of P. micros and 30 strains of other gram-positive cocci. All P. micros isolates tested grew and showed the typical morphology of P. micros on PMM. Using colony counts on CBM as controls, there was an average 81.8% recovery in the number of P. micros colonies on PMM, in contrast to an average 6.1% recovery on PEA. Subgingival plaque and tongue samples from 12 adult periodontitis and 6 early-onset periodontitis patients were cultured onto PMM for the isolation of P. micros. P. micros was isolated on PMM and identified biochemically and enzymatically from both adult periodontitis and early-onset periodontitis patients with higher percentages isolated from the diseased periodontal pockets of adult periodontitis patients; furthermore, this is the first isolation of P. micros from tongue samples taken from periodontally diseased patients. This medium in cultural studies will further our understanding and assist future investigations of P. micros involved in disease processes.

Effect of an antiseptic mouthrinse on salivary microbiota.

PURPOSE: To evaluate the effect of rinsing with original formulation Listerine Antiseptic (LA) on the level of viable salivary bacteria for periods up to 1 hour. MATERIALS AND METHODS: In this double-blind, controlled, cross-over study, unstimulated saliva was collected from 25 subjects, serially diluted, and cultured on selective and non-selective media under aerobic and anaerobic conditions. Streptococci, Veillonella sp., and total aerobic and anaerobic flora were enumerated just prior to and 2, 15, 30, and 60 minutes after rinsing for 30 seconds with either 20 ml of LA or a 5% hydroalcohol control rinse. RESULTS: After the control rinse, total flora cultivated on MM10 agar exhibited a non-significant (P > 0.05) 10%-20% decrease relative to baseline. In contrast, rinsing with LA resulted in a significant (P < 0.05) 60%-65% decrease from baseline in all four microbial groups at 2 minutes; except in the case of Veillonella, the significant decreases were sustained up to 60 minutes. Total Listerine group aerobic, anaerobic and streptococcal counts were significantly lower than placebo (P < 0.05). The significant reduction in salivary bacterial levels seen in the Listerine group for up to 60 minutes suggests that this antiseptic mouthrinse may have use clinically as a pre-procedural rinse to decrease the level of viable microorganisms in aerosols generated during dental procedures.

In vitro inhibition of bacteria from root canals of primary teeth by various dental materials.

The primary tooth pulpectomy is a common clinical procedure. The choice of filling material is important to the success rate, but antibacterial properties of such materials against organisms known to inhabit infected primary root canals have not been well documented. This study compared the antibacterial effectiveness of 10 materials: 1. Calcium hydroxide mixed with camphorated parachlorophenol (Ca(OH)2+CPC) 2. Calcium hydroxide mixed with sterile water (Ca(OH)2+H2O) 3. Zinc oxide mixed with CPC (ZnO+CPC) 4. Zinc oxide mixed with eugenol (ZOE) 5. ZOE mixed with formocresol (ZOE+FC) 6. Zinc oxide mixed with sterile water (ZnO+H2O) 7. ZOE mixed with chlorhexidine dihydrochloride (ZOE+CHX) 8. Kri paste 9. Vitapex paste 10. Vaseline (control) These materials were compared against microbial specimens obtained from 13 infected primary teeth by using an agar diffusion assay. The results suggest that the materials could be divided into three categories. Category I, with the strongest antibacterial effect included ZnO+CPC, Ca(OH)2+CPC, and ZOE+FC. Category II, with a medium antibacterial effect included ZOE+CHX, Kri, ZOE, and ZnO+H2O. Category III, with no or minimal antibacterial effect included Vitapex, Ca(OH)2+H2O, and Vaseline. There were no significant differences within each category, but there were significant differences between the categories. The one exception was the antibacterial effect of ZOE+FC which was not significantly different from ZOE+CHX, Kri, or ZOE.

Use of the Syrian golden hamster for the induction of intraoral abscesses by sutures contaminated with human subgingival plaque.

Analysis of normal oral flora in 150 cheek pouches of hamsters (Mesocricetus auratus) defined the microbial working environment and demonstrated the absence of human oral black-pigmented bacteria. Silk sutures saturated with Porphyromonas gingivalis, Prevotella intermedia or subgingival plaque were used to close wounds made in hamster's cheek pouches. Abscesses were formed when sutures had solitary P. gingivalis or other bacteria mixed with P. gingivalis or when P. intermedia was mixed with other bacteria besides P. gingivalis. A concentration of black-pigmented bacteria emanating from 3 x 10(5) colony-forming units/inoculum was required for abscess formation. Six abscesses (14.3%) were developed in association with the presence of other odontopathic bacteria, primarily Fusobacterium nucleatum and Actinomyces viscosus. The hamster cheek pouch with iatrogenic wounds closed with plaque-impregnated sutures is a novel and effective model to study the pathology of wound infections and virulence of human subgingival organisms.

Correlation between thermal sensitivity and microorganisms isolated from deep carious dentin.

The correlation between thermal sensitivity and the microorganisms present in 29 deep carious lesions was studied. The numbers of lactobacilli and total Gram-positive rods in the carious lesions were found to be negatively related to the length of pain triggered by cold and heat stimulants. The presence of Gram-positive cocci and non-black-pigmented Bacteroides were positively associated with both cold and heat sensitivities. Black-pigmented Bacteroides, Streptococcus mutans, and total anaerobic colony counts were positively related to the heat sensitivity. Recovery of Fusobacterium nucleatum, Actinomyces viscosus, and enterics on the selective plates was associated with cold sensitivity. Total counts of Gram-positive cocci and Gram-negative rods on the anaerobic nonselective medium were positively related to the cold sensitivity. It appeared that teeth with low numbers of lactobacilli in the carious lesions usually responded to thermal tests with longer duration of pain. Conversely, teeth with high numbers of lactobacilli in the carious lesions usually responded with shorter duration of pain.

Clinical effects of simultaneous ultrasonic scaling and subgingival irrigation with chlorhexidine. Mediating influence of periodontal probing depth.

The clinical and microbial effects of a single episode of simultaneous ultrasonic scaling and subgingival irrigation with chlorhexidine (CHX) were studied as a function of clinical probing depth in patients with adult periodontitis. 60 patients were randomly assigned to receive subgingival irrigation under cavitation with either sterile water or 0.12% CHX delivered through the tip of an ultrasonically activated scaler as part of initial periodontal therapy in a double-blind study design. 3 periodontal sites were randomly selected for examination from each patient on the basis of clinical probing depth, with 1 site being selected within each of the following ranges: 1-3 mm, 4-6 mm, and 7-9 mm. Pretreatment and post-treatment (days 14 and 28) clinical assessments included a plaque index (PI), gingival index (GI), and clinical probing depth (CPD). Subgingival specimens also were collected from 1-3 mm and 4-6 mm sites on a random subset of patients (15 per group). Plaque counts of spirochetes and motile organisms were made by darkfield microscopy. Significant reductions in PI, GI, and CPD were observed among all sites within both treatment groups at 14 and 28 days post-treatment. CHX irrigation resulted in a significantly greater reduction in CPD than did water among sites initially probing 4-6 mm at both 14 and 28 days post-treatment (25% versus 13% and 31% versus 18%, respectively). Spirochete counts were modestly but nonsignificantly reduced at 14 days post-treatment among sites 4-6 mm within both treatment groups. These results suggest that subgingival irrigation with CHX during ultrasonic scaling provides differential clinical benefits that are site-dependent.

Microbiological evaluation of periapical infections in Egypt.

This study identifies and correlates proportions of bacteria in periapically involved anterior teeth of 85 adult Egyptian patients. Affected sites were free from caries and periodontal disease but had a history of trauma. The mean number of component bacterial species per specimen was 3.1. Anaerobic bacteria were the dominant flora present in specimen cultures, comprising 73% (190/259) of cultivable bacteria. The most frequently isolated organisms were Eubacterium species (68%), black-pigmented Bacteroides (56%), Streptococcus morbillorum (47%) and non-pigmented Bacteroides (37%). These organisms also showed the highest proportional values relative to total cultivable bacteria. The mean percentages of total viable counts of these isolates were 19.0%, 14.1%, 18.0% and 15.5%, respectively. Statistical analysis of data revealed a significant negative correlation between S. morbillorum and Bacteroides species.

Microbiological studies of carious dentine from human teeth with irreversible pulpitis.

Aerobic and anaerobic cultures were made from 29 extracted teeth with irreversible pulpitis to identify the predominant flora in different parts of deep carious lesions. Most isolates were Gram-positive rods, in which lactobacilli were the most frequent organisms, then other Gram-positive, non-branching rods. Gram-positive cocci were the next most common; only a low number of Streptococcus mutans was recovered. Two types of carious lesions were found, one with high numbers of lactobacilli, the other with low. In the 15 lesions with high numbers, lactobacilli constituted 91.9% of the total flora at the pulpal site and gradually decreased in number as the sampling moved away from the pulp. Strep. mutans and alpha-haemolytic streptococci were not recovered from pulpal or deep carious sites in this group. In the 14 lesions with low numbers of lactobacilli, the flora was diverse. Gram-positive cocci, anaerobic Gram-positive non-branching rods, branching rods and/or Bacteroides were the main isolates in a few of this group.

Coaggregation of oral Candida isolates with bacteria from bone marrow transplant recipients.

In vitro coaggregation between Candida species isolated from immunosuppressed bone marrow transplant recipients and oral bacteria was investigated. Each Candida strain showed a different pattern of coaggregation with the 22 bacterial strains studied. Two strains of Lactobacillus amylovorus isolated from separate bone marrow transplant patients and Fusobacterium nucleatum (VPI 10197) coaggregated with all Candida strains. Ten bacterial strains showed no coaggregation with the Candida strains. A variety of inhibition patterns were observed when coaggregating strains were first incubated with various sugars or subjected to heat treatment. Positive and negative results were generally consistent with all Candida strains. On the basis of the culture characteristics of the oral rinse specimens, relationships between the colonization of bacteria and yeasts and in vitro coaggregation were suggested.

Effect of granulocytopenia on oral microbial relationships in patients with acute leukemia.

Risk for acute infection increases as granulocyte levels decrease secondary to myelosuppressive chemotherapy in patients with acute nonlymphocytic leukemia (ANLL). Acute exacerbations of concomitant inflammatory periodontal diseases can result in systemic infections in these patients. However, host-oral bacterial relationships in the periodontium in patients with ANLL are not well understood. Twenty-one adult patients with ANLL with periodontal disease ranging from gingivitis to severe periodontitis were studied. Supragingival and subgingival plaque specimens were collected before chemotherapy (prechemotherapy), and at a defined midpoint of myelosuppression (midchemotherapy; day 14). All specimens were extensively cultured both aerobically and anaerobically. Data were submitted to a partial correlational analysis, controlling for covariation relation to oral hygiene intervention and antibiotic administration. Levels of total yeast exhibited a significant association with Staphylococcus sp. at supragingival sites midchemotherapy (r = 0.68, p less than or equal to 0.05). Levels of total yeast also correlated positively with Pseudomonas aeruginosa at subgingival sites both prechemotherapy (r = 0.70, p less than or equal to 0.01) and midchemotherapy (r = 0.61, p less than or equal to 0.05). Significant correlations of levels of Veillonella sp. with Neisseria sp. and gram-negative enteric bacilli were observed in both supragingival (r = 0.95, 0.77, p values less than or equal to 0.01) and subgingival (r = 0.69, 0.61, p values less than or equal to 0.05) plaque specimens midchemotherapy but not prechemotherapy. These data suggest that potentially pathogenic bacteria occur in plaque simultaneous with granulocytopenia in these patients. Multiple mechanisms, including intergeneric coaggregation and other symbiotic relationships, may influence infectivity of the mixed plaque flora and thus contribute to the oral ecology observed in these patients.

Comparative effects of 2 chemotherapeutic mouthrinses on the development of supragingival dental plaque and gingivitis.

A 6-month double-blind, controlled clinical study was completed with 124 healthy adult subjects to determine the efficacy of 2 mouthrinses, Listerine (LA) and Peridex (PX), used as supplements to regular oral hygiene measures in reducing supragingival dental plaque and gingivitis. Following screening examinations for entry levels of existing gingivitis and plaque, baseline gingival and plaque area indices, extrinsic tooth stain, supragingival calculus, bleeding and soft tissue condition were recorded. All subjects then received a complete dental prophylaxis to remove plaque, calculus and extrinsic stain. Subjects were randomly assigned to 1 of 3 groups and performed supervised rinses twice daily for 30 s in addition to their normal oral hygiene, for 6 months. All indices were again evaluated at 3 and 6 months. After 6 months, LA and PX significantly (p less than 0.001) inhibited development of plaque by 36.1% and 50.3%, respectively, and the development of gingivitis by 35.9% and 30.5%, respectively, compared to a hydroalcohol control. PX was more effective in inhibiting plaque and both mouthrinses appeared to be equally effective in inhibiting gingivitis. LA patients did not develop significant levels of stain or supragingival calculus at 6 months, compared to baseline or control. PX patients developed significant levels of extrinsic stain and supragingival calculus compared to baseline and control. Though PX was more effective than LA in the control of plaque, this study indicates that both LA and PX were effective agents in a regimen for the control of plaque and gingivitis.

Clinical and microbial evaluation of treatment regimens to reduce denture stomatitis.

This study evaluated the effect of an antimicrobial mouthrinse, denture soft relines, and a placebo rinse on the clinical findings and microbial flora of 78 patients with denture stomatitis. For 28 days the study and control groups performed oral rinses and denture soaks. Reline group patients had maxillary denture soft relines that were changed every 7 days. At the end of the study, the mean severity of denture stomatitis was significantly less in the groups that used the study rinse (P less than 0.01) and received denture relines (P less than 0.05) compared to the control. Analysis of variance revealed significant differences in ranked adjusted percentage counts in two out of 13 denture plaque organisms investigated (Fusobacterium nucleatum [P less than 0.05] and total Bacteroides [P less than 0.05]), with the antiseptic rinse producing the lowest count. Yeast populations were reduced, but not significantly (P = 0.07). In the absence of other mechanical denture hygiene procedures, the antiseptic rinse and relines were equally effective in reducing denture stomatitis and potential pathogens of denture plaque flora.

Comparative microbiological and immunological studies of subgingival dental plaque from man and baboons.

Baboons may be useful as animal models for the study of human oral diseases and infections. They are closely related to man anatomically, physiologically, and phylogenetically. Plaque and gingival indices were relatively low in 18 baboons (Papio anubis). The mean scores ranged between 0.62 +/- 0.29 and 0.37 +/- 0.20, respectively. Gram-positive and Gram-negative cocci comprised 27.0 +/- 32.4 and 3.1 +/- 7.5% of the total viable counts in the dental plaque samples. Black-pigmented Bacteroides formed about 1.9 +/- 5.9% of the bacterial population in the samples. Anaerobic Gram-negative bacilli were found in 73.2% of the samples and averaged 19.2 +/- 26.3% of the total recovered flora. Species of the oral Actinomyces and other Gram-positive rods found in humans were not isolated. The composition of the oral flora in baboons appeared to be significantly different from that of man. Isolates of F. nucleatum, L. buccalis, and B. intermedius from the two mammals were biochemically similar, but were distinguishable by analysis with antibody, both by precipitin lines and/or differences between homologous and heterologous titers.