Estudio del efecto de la maltosa adicionada a un gel dental sobre el grado de infección por el streptococcus mutans en la saliva y sobre la higiene bucal: ensayo preliminar / Study of the effect of maltose added to a dental gel on degree of infection by streptococcus mutans in the saliva and oral hygiene: preliminary assay

Algunos autores han demostrado que la maltosa inhibe la formación de glucanos insolubles por el S. mutans, al interferir su mecanismo de adhesión. Esta investigación preliminar se realizó para conocer el efecto de la maltosa incorporada a un gel para el cepillado de los dientes, sobre el grado de infección por el S. mutans en la saliva y sobre la higiene bucal. En 8 participantes (personal estomatológico) se aplicó la técnica de Matsukubo (modificada) y se determinó la higiene bucal mediante los índices de Love y el IHB-S; se formaron 2 grupos y se utilizó una prueba cruzada en 2 etapas. Se halló que el cepillado con el gel-maltosa redujo el grado de infección por el S. mutans en el 50,5 % al compararse con el control, mientras que el efecto sobre los índices de higiene bucal no presentaron diferencias significativas. Se discuten los resultados y se concluye que se precisa valorar su efecto en la prevención de caries mediante un ensayo clínico de un año de duración

Biogenesis of methane in primate dental plaque.

Dental plaque samples collected from monkeys (Macaca mulatta) were found to contain a large amount of dissolved methane gas (0.6 nmol CH4/mg wet wt plaque). Enrichment cultures inoculated with dental plaque obtained from Macaca fascicularis produced methane when the medium contained ethanol, methanol, lactate, acetate or a hydrogen + CO2 atmosphere. Methane formation in the enrichments was inhibited by oxidation of the culture medium, autoclaving or the addition of 2-bromoethane sulfonic acid (BES). The methane producing enrichments were observed to contain fluorescent cocci occurring singly and in short chains. It was concluded that methane formation in the monkey dental plaque was the result of the presence of methanogenic bacteria.

Quantitative assessment of urea, glucose and ammonia changes in human dental plaque and saliva following rinsing with urea and glucose.

The rates of three processes associated with the rise and fall in plaque pH, that normally occur following a urea rinse, were determined: (i) disappearance of urea from plaque, (ii) disappearance of urea from saliva and (iii) formation and disappearance from plaque of the ammonia produced by the plaque bacteria from the urea. Also examined were two processes associated with the fall and rise in pH following a glucose rinse: the disappearance of glucose from plaque and from saliva. Entry into plaque of either urea or glucose during rinsing was immediate; the subsequent disappearance of both from the plaque was slow and followed first-order kinetics. The ammonia formation and urea-disappearance results suggested that clearance of urea from the plaque occurred mainly by bacterial degradation and not by diffusion out of the plaque. The rate constants for ammonia formation and for its subsequent disappearance from the plaque made it clear why a rapid rise and a slow subsequent fall in the pH occurs after urea rinsing. The rate constants enabled calculation of the ammonia produced as a percentage of the urea utilized. Only 16-26 per cent of the urea was recovered as ammonia and the remainder of the urea-N was stored probably as NH2 moieties of certain amino acids. Such storage may enable the plaque bacteria to maintain the pH at an elevated level for an extended period of time by bacterial production of ammonia from these stored compounds after the urea ceases to be available as a source of substrate.

Exposure time and the effect of hexylresorcinol on bacterial aggregates.

The bactericidal effect of hexylresorcinol was assessed using bacterial aggregates. Increased drug concentration resulted in decreased survival of bacteria when the aggregates were exposed to hexylresorcinol for at least eight hours. This indicates that this drug may be effective against dental plaque only when available for long periods of time.

Some effects of sugar-flavored acid beverages on the biochemistry of human whole saliva and dental plaque.

An investigation was made of the effects on some biochemical characteristics of human whole saliva and dental plaque resulting from the daily consumption of three commercial, acid-containing beverages. The beverages tested were a cola beverage ("Coca-Cola"), a carbonated orange drink ("Jaffa") and single strength orange juice. Each of the three test beverages as well as non-fluoridated tap water as a control, were consumed during four two-week periods. The test group consisted of 39 dental students. The mean consumption frequency lay in the range from 5.3 to 5.7 times per day. Orange juice was found to stimulate the salivary secretion rate most. All test drinks decreased the salivary pH immediately after consumption, but the pH did not generally drotase-like activity in oral fluid. Changes were observed in calcium, phosphate and fluoride concentrations in oral fluid samples, but these were due to variations in salivary secretion rate. A significant decrease in redox potentials of whole saliva was, however, observed after consumption of the drinks. The present results indicate that in healthy persons with normal saliva flow rate and buffer capacity the moderate consumption of acidic beverages failed to induce any remarkable caries-promoting changes in oral cavity. However, in persons with low salivary flow rate erosion may be a consequence of regular consumption.

The effect of chlorhexidine mouthrinse on healing after gingivectomy.

The purpose of this investigation was to evaluate the effect of 0.2% chlorhexidine gluconate mouthrinse following gingivectomy on plague under the dressing and on healing. Twenty-eight patients with indications for gingivectomy were selected. Coe-Pak was used as surgical dressing. In addition to unsual home care, the patients rinsed twice daily with chlorhexidine or placebo for 21 d after surgery. The study followed a cross-over double-blind design. Gingival exudate was assessed and Pl I and G I were registered at 7, 14, and 21 d postsurgically. The study indicated that chlorhexidine did not influence the amount of plaque under the dressing, and it was uncertain whether chlorhexidine had any effect on the healing process when the surgical area was covered by Coe-Pak. However, (1) after the surgical dressing was removed, the chlorhexidine maintained plaque scores at the same low level as under the dressing, (2) healing was was promoted when chlorhexidine was used, and (3) the presence of a dressing in one side of the mouth did not prevent the patient from maintaining good oral hygiene.