In vitro effects of an acidic by-product feed on bovine teeth.

ABSTRACT

OBJECTIVE: To evaluate in vitro erosive effects of sweet potato cannery waste (SPCW) on bovine incisor enamel. SAMPLE POPULATION 20 bovine mandibles. PROCEDURE Mandibles were collected and incisors were classified into 3 categories lacking observable wear, advanced normal wear, or abnormal wear associated with feeding SPCW. Intact mandibles were radiographed. Contralateral normal teeth from the same jaw were used to compare Ca2+ loss (etching) with SPCW, lactic acid (pH 3.2), or SPCW neutralized with NaOH to pH 5.0 or 5.5. Scanning electron microscopy was performed to compare etched and unetched specimens. Two abnormally worn teeth were evaluated histologically. Knoop hardness testing was conducted on unexposed areas of surface enamel and enamel exposed to SPCW. RESULTS: Radiography revealed large periapical abscesses in the mandibles exposed to SPCW. Nearly identical amounts of Ca2+ were removed by SPCW and lactic acid solution at the same pH. Scanning electron microscopy did not indicate consistent differences between etch patterns resulting from exposure to SPCW or lactic acid. Mean rate of calcium removal was 56% higher in deciduous than permanent teeth. Knoop hardness data suggested that softening occurred in enamel exposed to SPCW. Neutralizing SPCW to pH 5.5 eliminated calcium removal. Histologic examination of sections indicated that SPCW degraded and removed some dentin matrix proteins. CONCLUSIONS: Exposure to SPCW results in enamel erosion in vitro; low pH is the most likely cause of erosion. Neutralizing SPCW to pH 5.5 eliminated erosive effects. CLINICAL RELEVANCE Confirmation of SPCW's erosive effects on enamel in vitro supported the field diagnosis.