Oral clearance and acid production of dairy products during interaction with sweet foods.

UNLABELLED: Oral clearance and acid production were observed in 30 volunteers following the ingestion of sharp cheddar cheese (CC) and in 9 volunteers following the ingestion of milk chocolate (MC) and low-fat yogurt, and then when MC was eaten immediately after CC (CC/MC) and when CC was eaten following MC (MC/CC). After each test food or food combination had been ingested the volunteers were monitored at five different tooth sites. At each site, using an absorbent paper point, 4 oral fluid samples were collected at 30 min intervals. The five paper points from each sampling occasion were pooled, extracted with 1 ml of water and analyzed qualitatively and quantitatively for both carbohydrates and organic acids using HPLC. Data obtained for each food was averaged and subjected to statistical evaluation. With the CC, glucose clearance was prolonged, due to intermediate lactose degradation into galactose and glucose. The quantity of lactic acid produced during the four intervals was monitored for each of the test foods and their combinations. RESULTS: CC, MC, CC/MC, MC/CC 30 min after ingestion: 1.64, 3.47, 4.68, 2.97; after 60 min: 1.30, 1.24, 1.28, 1.43; after 90 min: 1.58, 1.02, 0.76, 0.43; after 120 min: 1.27, 0.90, 0.70, 0.42 mmol lactic acid/l oral fluid, respectively. The average total amount of lactic acid obtained during the two hour test period was (highest) CC/MC > MC > CC > MC/CC (lowest). The lowest amount of intra-oral lactic acid was observed (Student's t test, p < 0.05) when cheddar cheese (CC) was eaten immediately after the milk chocolate (MC). CLINICAL SIGNIFICANCE: Consumption of cheese (cheddar), immediately after a sweet meal, significantly reduces (approx. 30%) the amount of lactic acid produced in the oral cavity, when compared to the amount of acid obtained from the sweet food alone.

Effect of increasing sucrose concentrations on oral lactic acid production.

UNLABELLED: Oral lactic acid production was studied on 11 healthy dental student volunteers (5 males and 6 females) during clearance of five solutions containing 5, 10, 15, 20 and 30% of sucrose. Oral fluid samples were collected at times zero, immediately before taking the sucrose solutions ('baseline'), and 15 min following intake of the solutions. The samples were analyzed qualitatively and quantitatively for the presence of lactic acid and remaining sugars using high-performance liquid chromatography (HPLC). Results indicate that the amount of lactic acid in oral fluid significantly increased with increasing sucrose concentrations, up to 15% sucrose. With the higher sucrose concentrations (20 and 30%) equivalent or lower amounts of lactic acid were obtained. The threshold level for maximum lactic acid production was found to be between 10 and 15% sucrose. Statistical analysis of the data (Student's t test) indicated a significant difference in lactic acid production between the 5 and 10% sucrose solutions versus the 15, 20 and 30% sucrose solutions tested (p < 0.05). CLINICAL SIGNIFICANCE: Ingestion of solutions with higher sucrose concentrations (>15%) produced similar amounts or less of lactic acid during oral clearance than solutions containing lower sucrose concentrations (<15%).

Clearance and metabolism of starch foods in the oral cavity.

The presence of carbohydrates and organic acids was monitored in the oral cavity over a 3-hour period following the ingestion of six foods containing cooked starch (popcorn, potato chips, corn flakes, bread stick, hard pretzel and wheat cracker) and compared to a food containing sugar (chocolate-covered candy bar). Oral fluid samples were collected at 30-min intervals from five different tooth sites from 7 volunteers using absorbent paper points. Samples were analyzed for carbohydrates and organic acids using high-performance liquid chromatography. Analytical data for each food were pooled and compared to the results of the sugar food. The amount of lactic acid produced 30 min after ingestion was highest with the potato chips and lowest with the corn flakes. Potato starch contributed more readily to oral lactic acid production than wheat or corn starch. A direct linear relationship existed between lactic acid production and the presence of oral glucose produced from starch, which occurred via the metabolites maltotriose and maltose. Oral clearance of foods containing cooked starch proceeded significantly slower than that of the sugar food, thus contributing to a prolonged period of lactic acid production.

Intra-oral lactic acid production during clearance of different foods containing various carbohydrates.

Oral carbohydrate clearance and acid production were monitored over a two hour time period following the ingestion of six foods (chocolate bar, potato chip, oreo cookie, sugar cube, raisin and jelly bean). Each food was evaluated intra-orally in eight volunteers. Oral fluid samples were obtained from each volunteer at 30 min intervals at five different tooth sites using absorbent paper points. The oral fluid samples were analyzed qualitatively and quantitatively for carbohydrates and organic acids using high performance liquid chromatography. Data obtained for each food were averaged and subjected to statistical analysis. The quantity of lactic acid produced 30 min after ingestion was found to be in the following order: (highest) raisin > chocolate bar > sugar cube > jelly bean > oreo cookie > potato chip (least). Two hours after food intake the order had changed significantly: potato chip > jelly bean > sugar cube > chocolate bar > oreo cookie > raisin. A direct linear relationship existed between lactic acid production and the presence of glucose. In foods containing cooked starch prolonged clearance occurs via the intermediate metabolites maltotriose, maltose and glucose. Results indicated that the term 'stickiness', when used to label certain foods such as jelly bean and chocolate bar, should be used cautiously. Foods containing only cooked starch or cooked starch and sugars can be considered as 'sticky', since glucose arising from their intra-oral degradation contributed to acid production over prolonged periods of time.

Quantitation of catecholamines in uninflamed human dental pulp tissues by high-performance liquid chromatography.

The quantitation of catecholamines has yet to be reported in the human dental pulp. Various methods of chemical detection have shown the presence of catecholamines in pulpal tissue. Pulpal tissue was obtained from nonrestored, uninflamed teeth that needed to be extracted. The samples were collected, extracted, and analyzed by means of high-performance liquid chromatography with ultraviolet detection for levels of catecholamines (dopamine, epinephrine, and norepinephrine). As mediators of vasoconstriction, catecholamines play an important role in the control of intrapulpal pressure. This research describes a method for quantitation of catecholamines. Future studies investigating inflamed tissue can now be accomplished with the use of this analytic method. The results from this research indicate a baseline level of catecholamines in the uninflamed human dental pulp.

Synergistic growth studies of Entamoeba gingivalis using an Ecologen.

A unique multiple diffusion growth chamber, an Ecologen, designed for the study of interactions among microorganisms, was introduced as a means of growing xenic cultures of Entamoeba gingivalis with Crithidia sp. or Yersinia enterocolitica. Entamoeba gingivalis was grown in the central diffusion reservoir of the Ecologen connected to separate growth chambers inoculated with the microorganisms to be evaluated. Growth of the accompanying bacteria in the E. gingivalis compartment was almost completely eliminated, except for sparse Pseudomonas sp. growth. The most vital E. gingivalis cultures were observed when either Crithidia sp. or Y. enterocolitica were added to the Ecologen 48 h prior to the E. gingivalis inoculum. The medium which provided the best growth of the oral protozoan in this system was the new improved E. gingivalis medium containing antibiotics.

Quantitation of carbohydrate sweeteners and organic acids in human oral fluid using HPLC analysis.

A sensitive high performance liquid chromatography (HPLC) assay was developed for the qualitative and quantitative determination of carbohydrate sweeteners and organic acids in oral fluid. To separate these compounds, an ion-moderated partition resin HPLC column (Aminex HPX-87H) was used. All components of the HPLC system were interconnected using stainless steel capillary tubing. Isocratic elution with 0.01N sulfuric acid provided the profile of both compound classes. The compounds were detected using a refractive index detector. The method employed computerized data collection and integration (Omega-2 system) with a detection sensitivity of 0.1 micrograms compound per HPLC assay (80 microliters). This method is useful in caries research, because it detects minute amounts of sugars and organic acids in oral fluid during clearance studies of various foods in the mouth.

Tarnish of dental alloys by oral microorganisms.

Five dental alloys, on exposure to blood and chocolate media with and without inoculated microorganisms, showed varying degrees of tarnish. The results indicated a composition-dependent tarnish behavior of alloys in microorganism-inoculated media, indicating a potential role for the oral microorganisms in inducing clinically observed tarnish of dental alloys. Actinomyces viscosus and periodontal pocket specimens show a similarity in their activity to induce tarnish in base metal-containing dental alloys.

The challenge is in the handpiece.

Among the equipment recommended for today's dental office is a complete and easy-to-follow sterilization protocol. It may mean the difference between health and disease.

An antibiotic-free medium for the xenic cultivation of Entamoeba gingivalis.

Diamond's TYI-S-33 (Trypticase-Yeast Extract-Iron-Serum) medium was used as the basis for a new antibiotic-free medium for xenic growth of Entamoeba gingivalis. Nutritional requirements of the oral protozoan were determined in an effort to optimize growth. TYI-S-33 medium did not support E. gingivalis growth prior to modification. The changes included: (a) deletion of L-cysteine.HCl and thioctic acid, (b) substitution of glucose for dextran I (mol. wt 185,000) or rice starch, (c) reduction of concentrations of tryptone (2.5 g l-1), yeast extract (1.25 g l-1) and dextran I (1 g l-1), (d) increased concentration of ferric ammonium citrate (0.2 g l-1), and (e) addition of gastric mucin (2.4 g l-1). Dextran I was chosen as the major carbon source; its use in the medium limited growth of accompanying bacteria. This new antibiotic-free medium significantly increased E. gingivalis growth (16-20 E. gingivalis trophozoites observed per field) as compared to growth in Diamond's TYSGM-9 (Trypticase-Yeast Extract-Serum-Gastric Mucin) medium (six to 10 E. gingivalis trophozoites observed per field).

A new medium containing antibiotics for the xenic cultivation of Entamoeba gingivalis.

Diamond's trypticase-yeast extract-serum-gastric mucin (TYSGM-9) medium was studied for its suitability to support the xenic growth of the oral protozoan Entamoeba gingivalis. Amoebic growth was found to be best when the inoculum for transfer was 0.1 ml, the incubation temperature was 35 degrees C, and the interval between transfers was 48 h. These parameters were also useful for controlling the growth of accompanying bacteria. In addition, bacterial growth in xenic stock cultures, which had a direct effect on the activity of E. gingivalis trophozoites, was kept to a minimum by addition of the antibiotics piperacillin, erythromycin, neomycin, and penicillin. Varying substitutions and selected supplementations of TYSGM-9 medium led to the development of an improved medium for E. gingivalis. Supplements most beneficial for the growth of E. gingivalis trophozoites were ascorbic acid, ferric ammonium citrate, and special NCTC 107 vitamin mixture. As compared with TYSGM-9 medium (6-10 E. gingivalis trophozoites observed per field), the new E. gingivalis medium supported excellent growth (16-20 E. gingivalis trophozoites observed per field during optimal growth) of the oral protozoan. The medium is suitable for clinical isolation of E. gingivalis.

Isolation of acid producing sorbitol-adapted bacteria from dental plaque using selective agar media.

Acidogenic bacteria metabolizing sorbitol were isolated and identified from dental plaque of twenty nine volunteers, claiming to be users (sixteen) and non-users (thirteen) of sorbitol-containing chewing gum and candy. Sixty bacterial strains were isolated, using improved selective agar media. The taxonomy of twenty strains, all Gram-positive cocci, was determined employing a customized BBL MinitekR system and other biochemical reactions. The majority of these strains represented Streptococcus sanguis and Streptococcus acidominimus. Although sorbitol-metabolizing bacteria were found in plaque specimens of most persons tested, a larger number of acidogenic sorbitol degrading bacteria was detected in the plaque of the volunteer group claiming to use sorbitol-containing sweets. Bacteriological results indicate that frequent consumption of sorbitol-containing products will lead to a shift in oral ecology, numerically favouring sorbitol-metabolizing bacteria. These sorbitol adapted bacteria appear to be as acidogenic as Streptococcus mutans in the presence of ordinary sugars.

Growth studies on xenic cultures of Entamoeba gingivalis using established media.

Wantland's egg medium, modified Shaffer-Frye (MSF) medium and Tryptose-Trypticase-Yeast Extract-Serum-Blood (TTY-SB) medium were compared with variations of the latter two media for their ability to support xenic growth of Entamoeba gingivalis. Wantland's egg medium was unsuitable for growth of E. gingivalis. Accompanying bacteria became resistant to penicillin and streptomycin, overwhelming the amoeba culture. MSF medium was also unsuitable for the cultivation of E. gingivalis. Bacterial growth was heavy and protozoan growth sparse. MSF medium without mercaptosuccinic acid, but with rice starch, dextran or levan substituted for glucose and with Yersinia enterocolitica added, supported limited growth of the amoeba. Unmodified TTY-SB medium did not sustain growth of E. gingivalis. However, when rice starch suspension was substituted for glucose, L-cysteine HCl was deleted, and a Crithidia sp. was added to the E. gingivalis culture grown xenically, enhanced growth of the oral amoeba resulted in this modified TTY-SB medium. E. gingivalis is very sensitive to changes in incubation temperature. Optimum growth was found to be in the narrow range from 34.5 to 35 degrees C for all media tested.

Clinical survey of Entamoeba gingivalis by multiple sampling in patients with advanced periodontal disease.

A clinical survey of Entamoeba gingivalis was conducted in patients with advanced periodontal disease. A total of 100 specimens were taken from 10 patients (four females and six males) who were each sampled at 10 disto-facial random sites. The oral hygiene of the persons scored from good to fair to poor and very poor. The age of the test persons ranged from 20 to 68 years. All persons examined harbored E. gingivalis: the minimum prevalence was four sites positive out of 10 and the maximum prevalence was 10 sites positive out of 10 for the protozoan. It is recommended that for reliable testing of the presence of E. gingivalis at least five-10 different sites should be examined within the periodontium of each patient. Data reported earlier in the literature on the incidence of E. gingivalis--obtained after a single sampling per individual--are believed to be on average too low and, therefore, should be interpreted with caution.

Studies on the microflora associated with xenic cultures of Entamoeba gingivalis.

The microflora associated with xenic stock cultures (ATCC 30927) of Entamoeba gingivalis, the major protozoan of the human oral cavity, were isolated and identified as Citrobacter diversus, Yersinia enterocolitica, Acinetobacter anitratus and Pseudomonas maltophilia. In studies to determine whether the bacterial isolates were able to utilize rice starch as a sole carbon source, Y. enterocolitica exhibited excellent growth in rice starch minimal medium and TYSGM-9 medium (with rice starch), but growth was weak in TYSGM-9 medium (without rice starch). C. diversus, A. anitratus and P. maltophilia exhibited poor growth in rice starch minimal medium, but they produced excellent growth in TYSGM-9 medium with or without rice starch. In order to determine the effect of the rice starch hydrolysis on Entamoeba growth, the filtrate from each isolate grown in rice starch minimal medium was added to an E. gingivalis culture grown in TYSGM-9 medium. The filtrate from a Y. enterocolitica culture grown in rice starch minimal medium enhanced E. gingivalis growth, but the filtrates from cultures of C. diversus, A. anitratus and P. maltophilia suppressed E. gingivalis growth. This supported the concept that Y. enterocolitica is capable of metabolizing rice starch into intermediate products, which in turn can be utilized by the amoeba.

Effect of saccharin on growth and acid production of glucose-grown pathogenic and oral bacteria.

Growth and acid production of glucose-grown Gram-positive and Gram-negative rods as well as cocci from the human oral cavity were studied in the presence of 0.02 to 20.00 mg/ml sodium saccharin. All Gram-positive rods, i.e. Actinomyces viscosus, Lactobacillus acidophilus, Bacillus subtilis and Corynebacterium diphtheriae, and Gram-positive cocci, i.e. Streptococcus spp, Staphylococcus aureus and Micrococcus luteus, were significantly inhibited by saccharin, especially at the higher concentrations. While Gram-negative cocci, i.e. Veillonella sp and Neisseria sicca were strongly inhibited by all tested saccharin concentrations, Gram-negative rods, i.e. the enterics and Acinetobacter sp, exhibited little if any inhibition. Saccharin caused a significant reduction in fermentative acid production congruent with observed growth.