Comparison of Salivary pH, Buffering Capacity and Alkaline Phosphatase in Smokers and Healthy Non-Smokers : Retrospective cohort study

Fatemeh Ahmadi-Motamayel, Parisa Falsafi, Mohammad T. Goodarzi, Jalal Poorolajal


Objectives: Saliva contains alkaline phosphatase (ALP)—a key intracellular enzyme related to destructive processes and cellular damage—and has buffering capacity (BC) against acids due to the presence of bicarbonate and phosphate ions. Smoking may have deleterious effects on the oral environment due to pH changes which can affect ALP activity. This study aimed to evaluate the salivary pH, BC and ALP activity of male smokers and healthy non-smokers. Methods: This retrospective cohort study took place between August 2012 and December 2013. A total of 251 healthy male non-smokers and 259 male smokers from Hamadan, Iran, were selected. Unstimulated whole saliva was collected from each participant and pH and BC were determined using a pH meter. Salivary enzymes were measured by spectrophotometric assay. Results: Mean salivary pH (7.42 ± 0.48 and 7.52 ± 0.43, respectively; P = 0.018) and BC (3.41 ± 0.54 and 4.17 ± 0.71; P = 0.001) was significantly lower in smokers compared to non-smokers. Mean ALP levels were 49.58 ± 23.33 IU/L among smokers and 55.11 ± 27.85 IU/L among non-smokers (P = 0.015). Conclusion: Significantly lower pH, BC and ALP levels were observed among smokers in comparison to a healthy control group. These salivary alterations could potentially be utilised as biochemical markers for the evaluation of oral tissue function and side-effects among smokers. Further longitudinal studies are recommended to evaluate the effects of smoking on salivary components.


Saliva; Alkaline Phosphatase; Acids; Buffers; Smoking.

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Sultan Qaboos University Medical Journal, College of Medicine and Health Sciences, Sultan Qaboos University, PO Box 35, Postal Code 123, Al-Khod, Muscat, Oman

ISSN (Print edition): 2075-051X ISSN (Internet edition): 2075-0528

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