Need for an Instrument to Measure pH in Localized Areas of the Mouth

The loss of tooth structure in the cervical (neck) region of the tooth may occur as a result of (1) dental caries (decay), (2) abrasion (mechanical), (3) erosion (chemical), or (4) combinations of (1), (2), and (3). This may lead to the condition known as "sensitive neck" of the tooth. Lost structure in the cervical area, just as in other parts of the tooth, must be replaced by means of fillings. Our problem is to prevent cervical tooth destruction and its subsequent unpleasant sequelae. The shallow, narrow gingival crevice around the neck of the tooth contains a fluid, the pH of which may or may not agree with that of the saliva. An acid fluid may decalcify the tooth structure with which it is in contact in the cervical region. Since the great majority of lesions occur on the side of the tooth next to the lip or cheek, does the fluid in the gingival crevice vary in pH locally in relation to a single tooth? The problem demands a much more sensitive indicator than the litmus papers which are in present use. The instrument must be capable of use directly in the oral cavity, and must require a minimum of fluid. The author has reviewed the literature concerning technics for measuring pH, and has discussed the subject with a number of investigators who are using such methods. Since these methods do not give promise of easy adaptability to the present problem, they are not discussed here.