Abstract
Dental erosion is the loss of tooth structure by dissolution with acid that is not bacterial in origin. The acid that causes dental erosion can originate from the food and drink consumed, or it may be stomach acid that is regurgitated into the mouth. The loss of tooth structure is permanent and frequently results in increased sensitivity, loss of vertical dimension, the need to restore teeth and/or loss of tooth vitality. Children who present with erosion in the primary or early mixed dentition represent a critical age group. As the permanent teeth are erupting they will be more susceptible to erosion because of the immaturity of the enamel. Currently, the diagnosis of dental erosion depends on the history, diet questionnaires and records to illicit the source of acid. It would be ideal to be able to measure changing pH in the mouth during normal daily activity. Therefore, the purpose of the current research project was to develop a wireless pH-monitoring device that could be placed in an appliance and worn in the mouth of a child to record intraoral pH over the course of 24 hours.
A battery-operated pH telemetry system that incorporated a commercially available antimony pH electrode was developed. The system recorded pH readings every 4 seconds and stored the data to a flash memory chip that was later downloaded to a PC for analysis. Following calibration of the pH data, it was displayed in a graph of pH vs time to highlight the timing of the pH changes that occurred and relate the readings to the recorded ingestion of foods and drinks.
Laboratory experiments were carried out to determine the accuracy of the wireless pH telemetry system in conditions similar to those in the mouth. The pH readings it recorded were compared with readings taken by an antimony-based esophageal pH monitoring system used for the detection of acid reflux, and a laboratory glass pH electrode. The wireless pH telemetry system recorded results that were closest to those of the glass pH probe, and similar to those of the esophageal pH monitoring system.
Different methods of sealing the electrical components of the wireless pH telemetry system were tested to prevent leakage when inside the mouth. A series of intraoral trials were conducted using modifications to the appliance to hold the wireless pH telemetry system in a stable and comfortable position against the palate in the mouth. All of the intraoral trials recorded telemetric data for differing periods before moisture contamination caused corruption of the data. The later two intraoral trials resulted in recorded pH telemetric data for longer than 18 hours. In both cases the pattern of pH changes over time showed changes in pH that correlated to acid events recorded in the diet record. No decreases in pH were detected during sleep in these two trials. The final design of the intraoral appliance with the telemetry components is similar in size and shape to that of a rapid palatal expansion orthodontic appliance, which is used routinely in children.
The wireless pH telemetric system developed during this research has the potential to be used successfully in children. Future research with the wireless pH telemetry system should include collecting intraoral pH telemetric data from children with, and without signs of dental erosion to compare pH profiles and the timing and duration of acid conditions in their mouths. Confirmation of the wireless pH telemetry system’s capability to identify the source of acid, the timing and the duration of the pH drop should allow it to be used clinically as a diagnostic tool.