The influence of sampling method on electrolyte concentrations, ph and buffer capacity of saliva in healthy individuals

Abstract

Introduction Saliva is a complex secretion, which plays an important role in maintenance of oral health. Analysis of saliva is fast, simple and non-invasive, and it is increasingly used as a biological sample for determination of various biochemical markers. The aim was to determine the influence of unstimulated saliva collection methods for measuring electrolytes concentration (sodium, potassium, calcium), pH and buffer capacity of saliva in healthy subjects. Material and methods 30 healthy subjects, males and females, aged 18 to 20 years, without oral and systemic diseases were included in the study. Unstimulated saliva samples were taken using a special tube (Salivette) and via direct spitting into the test tube. The concentrations of sodium and potassium were determined by flame emission photometry while spectrophotometry was used for calcium concentration. For the analysis of pH value of saliva pH-meter was used, while saliva buffer capacity was determined by titration with HCl (0.005 mol/L). Results The level of sodium in unstimulated saliva collected in test tubes was 8.43 ± 3.92 mmol/L and in special tubes 7.90 ± 4.33 mmol/L. Potassium level in unstimulated saliva collected in test tubes was 13.62 ± 0.99 mmol/L while in special tubes it was 13.54 ± 0.94 mmol/L. Mean values of sodium and potassium in unstimulated saliva didn't show statistically significant difference in their concentrations between the two methods of collecting saliva. In contrast to these electrolytes, calcium concentration was higher in the samples of saliva collected with special tubes (2.04 ± 1.05 mmol/L) compared to the samples taken by direct spitting into the test tube (1.38 ± 1.18 mmol/L) with statistically significant difference (p lt 0.05). By analyzing the pH of unstimulated saliva it was found that the average pH value of saliva collected with special tubes was 7.05 ± 0.32, and after direct spitting into test tubes it was 7.35 ± 0.41. Buffer capacity of saliva in healthy subjects was lower after taking with special tubes (5.18 ± 0.74) compared to test tubes (5.36 ± 0.85), but without statistical difference. Conclusion Unstimulated saliva collecting methods using cotton pads (salivette) and direct spitting in the test tube did not affect the value of pH, buffer capacity, the concentrations of sodium and potassium, but affected the concentration of calcium in saliva from healthy subjects.

Uvod Pljuvačka je složen sekret koji ima značajnu ulogu u održavanju oralnog zdravlja. Analiza pljuvačke je brza, jednostavna i neinvazivna, pa se sve češće koristi kao biološki uzorak za određivanje različitih biohemijskih markera. Cilj ovog rada bio je da se proceni uticaj metode sakupljanja nestimulisane pljuvačke na koncentraciju elektrolita (natrijuma, kalijuma, kalcijuma), pH i puferski kapacitet pljuvačke kod zdravih ispitanika. Materijal i metode rada U istraživanje je uključeno 30 zdravih ispitanika muškog i ženskog pola, starosti od 18 do 20 godina, bez oralnih i sistemskih oboljenja. Uzorci nestimulisane pljuvačke su uzimani pomoću specijalnih epruveta - saliveta, i direktnim ispljuvavanjem u epruvete. Koncentracije natrijuma i kalijuma u pljuvački određivane su metodom plamene emisione fotometrije, a koncentracija kalcijuma metodom spektrofotometrije. Za analizu pH pljuvačke korišćen je pH-metar, a puferski kapacitet pljuvačke je određivan titracijom sa HCl (0,005 mol/L). Rezultati Koncentracija natrijuma u nestimulisanoj pljuvački sakupljenoj epruvetama iznosila je 8,43 ± 3,92 mmol/L, a u salivetama 7,90 ± 4,33 mmol/L. Koncentracija kalijuma u nestimulisanoj pljuvački sakupljenoj epruvetama iznosila je 13,62 ± 0,99 mmol/L, a u salivetama 13,54 ± 0,94 mmol/L. Analiza natrijuma i kalijuma u nestimulisanoj pljuvački nije pokazala statistički značajnu razliku u njihovoj koncentraciji između dve metode sakupljanja pljuvačke. Za razliku od ovih elektrolita, koncentracija kalcijuma je bila veća u uzorku pljuvačke sakupljene salivetama (2,04 ± 1,05 mmol/L) u odnosu na uzorak koji je uzet direktnim ispljuvavanjem u epruvetu (1,38 ± 1,18 mmol/L), sa statistički značajnom razlikom (p lt 0,05). Analizom pH nestimulisane pljuvačke utvrđeno je da je srednja pH vrednost pljuvačke sakupljene salivetama 7,05 ± 0,32, a direktnim ispljuvavanjem u epruvete 7,35 ± 0,41. Puferski kapacitet pljuvačke zdravih ispitanika je bio niži nakon uzimanja salivetama (5,18 ± 0,74) nego epruvetama (5,36 ± 0,85), ali bez statistički značajne razlike. Zaključak Metode sakupljanja nestimulisane mešovite pljuvačke pomoću pamučnih uložaka (salivete) i direktnim ispljuvavanjem u epruvete ne utiču na vrednost pH, puferski kapacitet, koncentraciju natrijuma i kalijuma u pljuvački, ali utiču na koncentraciju kalcijuma u pljuvački zdravih ispitanika.