Relation between buccal protozoa and pH and salivary IgA in patients with dental prothesis

Patricia PONCE DE LEÓN María ZDERO María D. VASCONI Isabel NOCITO Ada LUCCA Beatriz PEREZ About the authors




Entamoeba gingivalis and Trichomonas tenax are human buccal protozoa. They live in dental tartar, in the necrotic mucosa of the cells and the gingival fringes of the gums6.

The complexity of the oral environment and the multifactorial nature of the caries lesion, with the consequent loss of dental pieces, requires the cooperation of other disciplines such as Microbiology, Chemistry and Dietetics. Both partial and total loss of dental pieces produce modifications in buccal biotic conditions1.

Some investigators think that E. gingivalis is an agent which causes periodontitis7, while others consider it an opportunist capable of survive in the medium induced by periodontal disease5.

T. tenax, in spite of being considered as a commensal might take part in the first phases of the process of destruction of periodontal tissues6 owing to the finding of an acid phosphatase3, a surface protein similar to fibronectine6 and an important collagenolytic activity6.

The objetive was to determine the frequency of these two protozoa and their relation with salivary IgA and with salivary pH in patients with dental prothesis.

Fifty adult patients with either fixed or mobile prothesis were selected. Tartar and/or dental plaque samples of the 4 inferior incisors were obtained by means of a scaler, as well as a saliva sample was taken from each of the patients. Both were collected in the morning with no previous brushing or, in other cases, after a period of at last three or four hours after the last buccal hygiene.

Tartar, as well as dental plaque were diluted with sterile physiologic solution and was observed through an optical microscope (100x and 400x).

There was a previous microscopic observation of saliva followed by another observation after 2000 r.p.m. centrifugation during 5 minutes (100x and 400x) to identify protozoa.

Both samples were coloured with Gomori trichromic stain11 and cultured at 37 °C in the following specific media: Bacto Endamoeba Medium for E. gingivalis and Diamond medium4 for T. tenax. Cultures were daily observed for 72 hours.

In saliva samples, pH was determined by means of strips of indicant paper (V.N.: 6/0-7/5), and secretory IgA concentration was determined by the radial immunodiffusion method10 (V.N.: 20-40 mg/dl).

The statistical analysis was performed by the c2 test (signification level 0/05) so as to study the association between pH and IgA with the presence of parasite2.

Out of the 50 examined patients, 36 (72%) presented parasites, 29 were monoparasitized, 26 presented E. gingivalis and 3 presented T. tenax; the other 7 presented both protozoa.

The frequency of E. gingivalis in the population studied was 66% and 20% for T. tenax. Both protozoa were predominant in the tartar sample, and/or the dental plaque.

The cultures performed for the search of T. tenax increased significantly the diagnostic sensitivity, since out of the 10 positive patients, 5 were diagnosed only through the culture. However, for E. gingivalis, neither the culture nor the trichromic coloration increased sensitivity.

Out of the 36 parasitized patients, 26 presented normal value of secretory IgA, 6 showed values higher than normal and 4 were lower then normal values.

The pH salivary ranges in these patients were the following: 2 individuals with pH 5/0-5/5; 11 with pH 6/0–6/5; 17 with pH 7/0–7/5; 4 with pH 8/0–8/5 and 2 with pH 9/0–9/5.

The statistical study revealed that there might be no association between the presence of parasite and the two variables studied, IgA (p = 0/332 ) and pH ( p = 0/656).

The flora present in the microbiological plaque of dental protheses may be the cause of infection, not only at local level but also of other systemic infections owing to the co-existence of predisposition factors in the host.

At present, various investigators are relating dental protheses with high predisposition to caries as well as to the progression of periodontal disease.

This study shows high frequency of buccal parasites in patients with dental prothesis (72%). The frequency of oral parasites is higher than what has been communicated by some authors for a population with healthy mouths (50%)12 and similar to the values found in patients with the buccal pathology (78%)13.

The frequency of E. gingivalis was higher than that of T. tenax, as it occurred with both mentioned populations above12,13.

Statistical studies demonstrated that IgA and pH are independent of the presence of these buccal parasites, coinciding with previous investigations8,13.

Bioq. Patricia PONCE DE LEÓN

Dra. María ZDERO

Bioq. María D. VASCONI

Bioq. Isabel NOCITO

Dra. Ada LUCCA

Est. Beatriz PEREZ

Dpto de Microbiología. Area Parasitología

Facultad de Cs. Bioquímicas y Farmacéuticas

Suipacha 531. 2000 Rosario, Argentina



We thank Mrs Prof Aurelia Vicens de Robson for her reading and correction of the manuscript.


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8. PONCE de LEÓN, P.; ZDERO, M.; VASCONI, M.D. et al. - Protozoarios buccales en pacientes inmunocomprometidos y su relación con el pH y las inmunoglobulinas. Arch. Odonto Estomat., 16 : 371-375, 2000.

9. RIBAUX, C.L. - Étude du protozoaire Trichomonas tenax en microscopie électronique á balayage et en transmission. J. Biol. buccale, 7: 157- 168, 1979.

10. ROITT, I. - Inmunología esencial. 6 ed. Barcelona, Ed. Jims, 1988. p. 40-41, 69-75.

11. SHORE GARCIA, L. & ASH, L. - Diagnóstico parasitológico. Buenos Aires, Ed. Americana, 1983.

12. ZDERO, M.; PONCE de LEÓN, P.; VASCONI, M.D. & NOCITO, I. - Parásitos bucales: hallazgos de Entamoeba gingivalis y Trichomonas tenax. Acta bioquím. clín. lat.-amer., 30: 245-250, 1996.

13. ZDERO, M.; PONCE de LEÓN, P.; VASCONI, M.D.; NOCITO, I. & LUCCA, A. - Entamoeba gingivalis y Trichomonas tenax: hallazgo en poblaciones humanas con y sin patología bucal. Acta bioquím. clín. lat.-amer., 30: 359- 365, 1999.

Received: 08 January 2001

Accepted: 20 February 2001

Publication Dates

  • Publication in this collection
    06 Sept 2001
  • Date of issue
    Aug 2001
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