Cysteine challenge test as a novel diagnostic tool to distinguish oral halitosis

• Published in: Australian dental journal Vol. 67; no. 1; pp. 69 - 75
• Main Authors: Aydin, Murat, Gunay, Ismail
• Format: Journal Article
• Language: English
• Published: Australia 01.03.2022
• Subjects: Bad breath; Cysteine; differential diagnosis; halitosis; Halitosis - diagnosis; Humans; hydrogen sulphide; Mouth; oral malodor; Retrospective Studies; Bad breath; differential diagnosis; hydrogen sulphide; oral malodor; halitosis
• ISSN: 0045-0421; 1834-7819
• DOI: 10.1111/adj.12884

Background The cysteine challenge test is often used to check the H2S production capacity of the mouth. Patients with oral halitosis group (n = 305) or non‐oral halitosis group (n = 191) and healthy individuals (control group, n = 102) were compared with each other to identify any possible relationship between initial and cysteine‐induced oral H2S concentrations. Subjects and Method The medical records of 598 participants were reviewed retrospectively. Oral H2S concentrations before (pre‐CR) and after cysteine rinse (post‐CR) with 5 mL of 20 mmol L‐cysteine solution for 30 s were compared. Results Pre‐CR H2S concentrations were >0.8 ppm in 75.1% of oral group patients but less than <0.8 ppm in 87.3% of the non‐oral group and 86.9% of controls. After cysteine rinse, oral H2S concentrations exceeded 12 ppm in 72% of the oral halitosis patients but were lower in 88% of non‐oral group and 99% of controls. Whilst post‐CR/pre‐CR ratio was >12 in 74.5% of the oral group, it was <12 in 81.7% of the non‐oral group and 83.4% of controls. Conclusion Cysteine challenge test can be used as a diagnostic tool to identify an individual's tendency to produce oral malodor, not only to quantify momentary halitosis level.