Determining the efficacy of potassium oxalate containing strips to reduce dentinal fluid flow in situ

Abstract

The consensus stands that dentine hypersensitivity is caused by stimulus applied to exposed dentinal tubules inducing movement of fluid through the tubules and subsequent activation of mechanoreceptors and correlated pain sensation. The study aims were to test the ability of three solutions to remove any smear layer and leave patent dentine tubules following sectioning. To establish a standard sample brushing protocol for stabilising hydraulic conductance of dentine. To develop a flow cell model to measure the efficacy of a gel strip containing 3.14% potassium oxalate to occlude dentinal tubules as well as adapting the model to include an in situ phase. Finally, to corroborate any findings with dentine micrographs. Hydrodynamic flow rates were measured at baseline and post 10 minute treatment, some discs were left untreated. One treated and one un-treated disc were housed in palatal appliances worn by 20 participants for consecutive 14 days. Following the in situ phase, flow rates were re-measured and dentine discs were imaged using FIB-SEM and EDX before being fractured and imaged with SEM. Treated discs showed a reduction in flow rate from 90.3µl/min at baseline to 36.7µl/min following treatment, which was highly significant (p<0.0001). Following oral housing the flow rate was further reduced to 9.6µl/min. The flow rate of the non-treated discs reduced from 123.8µl/min at baseline to 40.0µl/min after oral housing, also highly significant (p<0.0001). Flow rate comparisons between treated and non-treated discs following housing in the oral environment showed that treated discs provided a significantly greater reduction in flow rate compared to non-treated discs (p=0.0038). Micrographs allowed identification of crystalline blockages within the dentine tubules of treated samples, supporting the results from the flow cell. This model was effective in showing the immediate occluding potential of the treatment whilst also showing its resilience following 14 days exposure to the oral environment.

Date of Award	1 Oct 2019
Original language	English
Awarding Institution	University of Bristol
Supervisor	Sian B Porter (Supervisor) & Nicola X West (Supervisor)