Microhardness Evaluation of Human or Bovine Enamel or Dentine Supporting Oral Care Product Testing

In vitro surface microhardness evaluation of human or bovine enamel or dentine supporting oral care dentifrice product development, testing and marketing claims

The evaluation of surface microhardness (SMH) of human or bovine enamel or dentine is a fundamental element in evaluating the integrity of dental hard tissue. It is often used as a surrogate measure of the ‘healthiness’ of the enamel or dentine surface. Acid-challenged or demineralized tissue tends to be softer whereas healthy or remineralised tissue is harder. SMH testing is routinely used as the principle measure during in vitro pH cycling testing where the remineralisation potential of different dentifrices - often containing fluoride - can be compared in the laboratory. It is also used to test the integrity of enamel during in situ remineralisation/demineralization clinical testing.

Oral care dentifrices regularly undergo re-formulation in order to improve some aspect of dental care whether it be cosmetic (whitening, sensory feel, freshness) or therapeutic (plaque/gingivitis prevention, enamel care). The ability of fluoride dentifrices to protect or repair enamel is a core attribute which requires periodic testing in order to support product claims or satisfy Regulatory bodies. In vitro and clinical in situ studies are often used to provide such support and SMH measurement is a key aspect of the testing.

Our in vitro laboratory team has several surface microhardness machines available with which to probe the integrity of enamel and dentine, all run with the latest software packages. Using using artificially demineralized enamel tissue as test substrates, we can provide you with data derived from Knoop or Vickers indenters and can help you with the design of the study itself, depending on your specific aims. All our analysts are fully trained and cross-calibrated. 

Measurement of SMH generally involves placing 5-10 indents per sample and calculating the mean indent length or hardness value. In situ remineralisation studies involve prior surface softening of the enamel with fruit juices or citric acid solutions or gels. 

We are also happy to tailor in vitro pH cycling demineralisation / remineralisation studies to your particular needs and can work with you to develop the best possible test protocol.

For over 20 years our Clinical Research Services group has been a trusted partner for developers and manufacturers of oral care products. We provide a Total Quality Assured one source solution for in vitro studies providing robust data to support the performance, efficacy and safety of novel oral care products.