Using mid infrared technology as new method for the determination of the dwell time of salivary substitutes on three dimensional gingiva models

Abstract

Background: Many people suffer from dry mouth (xerostomia) due to radiotherapy treatment of head and neck cancer, diseases like Sjogren's syndrome or as adverse effects to prescribed medications. Salivary substitute products like gels or sprays are often used for treatment. Efficacy of those oral care products are regularly assessed by validated or even not validated questionnaires. To determine the adhesion effect over time more objectively a new and sensitive method was established. The following study was designed to assess the dwell time of different oral care products in vitro.

Method: Two different types of surfaces were covered with oral care products and washed using a definite protocol with artificial saliva salt solution. First, oral care gels or oral care sprays were spread to a polystyrene surface of 2.25 cm(2), then onto cell based three-dimensional gingiva models. The surfaces were washed ten times with artificial saliva salt solution. The resulting washing solutions were examined using mid infrared spectroscopy in order to detect ingredients of the oral care products.

Results: All assessed oral care gels or oral care sprays and their components were detected very sensitive. Even traces of the products were detected in the eluent and thus enabled to differentiate the dwell times of the different products. In general, the dwell time of oral care gels on polystyrene or gingiva models was longer than that of oral care sprays. The use of gingiva models improved the differentiation between different products.

Conclusions: MIR spectroscopy turned out to be a sensitive method to detect salivary substitutes. Differences between single components and different products can be detected. The described method is a simple, reliable and easy process to evaluate the dwell time of oral care products in vitro and thus a useful tool to design optimised salivary substitute products.

Ethics: This is an in vitro study. No ethics or consent was required for this study.

Keywords: Dry mouth; Dwell time; Gingiva; Mid infrared spectroscopy; New method; Oral care; Salivary substitutes; Sjorgren’s syndrome; Xerostomia.

Fig. 1

Sensitivity of the analysis method. Absorption spectrum of aldiamed gel in five dilutions (C1 = 1:25; C2 = 1:50; C3 = 1:100; C4 = 1:250; C5 = 1:500)

Fig. 2

Dwell time of the different salivary substitute products on polystyrene and cellular gingival model (n = 3, mean ± SD)

Fig. 3

Absorption spectra of the solutions after the single rinsing steps (P01-P10) after application of aldiamed gel on polystyrene (a, c, e) and cellular gingival model (b, d, f)

Fig. 4

PCA analysis of the four main components of aldiamed gel in the washing steps 1–10 and pure washing solution (LM)