Evaluation of Oral Dryness and the Salivary-flow Rate in Patients with Oral Lichen Planus

Varisa Assapattarapun1, Sineepat Talungchit1, Pimporn Jirawechwongsakul1, Patrayu Taebunpakul1, *
1 Department of Oral Surgery and Oral Medicine, Faculty of Dentistry, Srinakharinwirot University, Bangkok, Thailand

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© 2022 Assapattarapun et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Department of Oral Surgery and Oral Medicine, Faculty of Dentistry, Srinakharinwirot University, 114, Sukhumvit 23, Wattana, Bangkok, 10110, Thailand; E-mail:


Background and Objectives:

Oral lichen planus (OLP) is a common T-cell-mediated inflammatory oral mucosal disease. One of the complaints among OLP patients is xerostomia. However, the relationship between oral dryness and a decreased salivary-flow rate in these patients is not yet conclusive. So, we investigated oral dryness and the salivary-flow rate in OLP patients using various measurements.

Material and Methods:

Thirty OLP patients and 30 controls were included. The oral-dryness symptoms were collected using the Xerostomia Inventory (XI) and Bother Index (BI). The salivary-flow rate was measured using a Modified Schirmer Test (MST) and the spitting method. The clinical signs of dry mouth were determined by the clinical oral-dryness score (CODS). The Thongprasom score was used to evaluate the severity of OLP. The data were analyzed using the Mann-Whitney U test and Spearman’s rank correlation coefficient.


The XI score and BI score in the OLP group were significantly higher than in the control group. However, CODS, MST, the unstimulated salivary-flow rate, and the stimulated salivary-flow rate were not significantly different between the two groups. There was no correlation between oral dryness and the salivary-flow rate in OLP patients. The severity of OLP was also not correlated to oral dryness and the salivary-flow rate.


OLP patients had more complaints about mouth dryness than the controls. However, the salivary-flow rates between the two groups were not different. Additionally, the severity of OLP was not related to dry mouth or the salivary-flow rate. The possible reasons for oral dryness among people with OLP require further investigation.

Keywords: Modified schirmer test, Clinical oral dryness score, Oral dryness, Oral lichen planus, Salivary flow rate, Xerostomia.