Bluetooth LE wireless monitor enables continuous oral health management

The Lura Health Oral pH monitoring system employs Nordic Semiconductor’s nRF52810 WL-CSP SoC to power wireless connectivity in ultra small tooth-worn acidity detector

Nordic Semiconductor today announces that Cambridge, MA-based health tech company Lura Health has employed Nordic’s Bluetooth® Low Energy (Bluetooth LE) nRF52810 Wafer Level Chip Scale Package (WL-CSP) System-on-Chip (SoC) in its ‘M1000’ tooth sensor. The sensor is part of the company’s ‘Lura Health Oral pH Monitoring System’ that enables both dentists and their patients to continuously monitor saliva pH levels and work together to create personalized oral health strategies.

pH sensor and temperature sensor

The M1000 sits on the patient’s tooth and features a pH sensor to monitor oral acidity, and a temperature sensor to compensate for temperature impacts on the pH sensor results. Hydroxyapatite—the primary component in tooth enamel—is dissolved out of the enamel in overly acidic environments. The device continually monitors oral pH levels throughout the day and transmits pH data to the patient's Bluetooth 4.0 (and later) smartphone at 15 minute intervals using Bluetooth LE wireless connectivity enabled by the Nordic SoC.

The Nordic SDK, along with all of the available testing applications were unexplainably helpful

Noah Hill, Lura Health

From the iOS and Android-compatible ‘Lura Health’ patient smartphone app, the user can view their current oral pH data and historical trends, as well as receive recommendations for products that can assist in managing oral health such as mouthwash, pH neutralizing sprays or other readily available pH neutralizing products. The data is also shared with the patient’s dentist via the Windows-, Linux- and MacOS-compatible Lura Health dentist web portal. The intuitive interface offers insights into the patient’s oral pH trends, letting the dentist view data for specific days and date ranges, and identify instances when pH levels are outside certain parameters. This lets the dentist keep track of potential issues with the patient’s oral pH levels over the six months between dental checkups, and manage oral health in a personalized, data-driven way.

Size as a critical variable

As the M1000 is designed to fit around a tooth continually for six months, the device’s size and battery life were crucial factors in its design. The nRF52810 WL-CSP reduced footprint of 2.4 by 2.4mm is approximately one sixth the size of the conventionally packaged nRF52810 SoC and the M1000 can operate for six months without recharging or replacing batteries. The nRF52810 has been engineered to minimize power consumption with features such as the 2.4GHz radio’s 4.6mA peak RX/TX currents and a fully-automatic power management system that reduces power consumption by up to 80 percent compared with Nordic’s nRF51 Series SoCs.

Nordic’s nRF52810 multiprotocol SoC combines a 64MHz, 32-bit Arm® Cortex® M4 processor, with a 2.4GHz multiprotocol radio (supporting Bluetooth 5.2, ANT™, and proprietary 2.4GHz RF protocol software) featuring reduced radio energy consumption, with 192kB Flash memory and 24kB RAM. The nRF52810 SoC is supplied with the latest version of Nordic’s S112 SoftDevice, Bluetooth 5-compliant RF protocol software. Nordic’s software architecture includes a clear separation between the RF protocol software and the customer’s application code. This simplifies development, and ensures the SoftDevice doesn’t get corrupted when developing, compiling, testing, and verifying application code.

“Since our device needs to fit around one tooth, size is one of the most critical variables for component selection and was the primary reason we began to evaluate the nRF52810,” says Noah Hill, COO and Co-Founder of Lura Health.

“The Nordic SDK, along with all of the available testing applications were unexplainably helpful. The Nordic DevZone forum has also been very useful, as I can receive incredibly detailed responses from Nordic engineers in often less than 24 hours, regardless of what problem I am facing.”

The Lura Health M1000 intraoral pH monitor is currently in development. The product is not available for sale or distribution in the United States.