Industrial dental erosion: a cross-sectional, comparative study.

Occupational exposure to sulphuric acid mist (H2SO4) is a health hazard. The threshold limit value-time weighted average (TLV-TWA) of exposure to H2SO4 recommended by the American Conference of Governmental Industrial Hygienists (ACGIH, 1994-1996) is 1 mg/m3. This single-blind study conducted in an electro-winning facility in South Africa, compared dental erosion of anterior and premolar teeth of male workers exposed daily to H2SO4 in an exposed group (H2SO4 range: 0.3 mg/m3-1 mg/m3) and an unexposed group (H2SO4 range: 0.1 mg/m3-0.3 mg/m3). The exposed group comprised all workers at the facility exposed to the aforesaid range of H2SO4 (N = 103). A total of 102 unexposed subjects similar in composition with respect to age and length of service were randomly selected from the rest of the 700 workers at the facility. A questionnaire was administered to seek information on possible worker habits associated with dental erosion and to determine perceptions of oral function. Clinical examinations assessed prevalence and severity of dental erosion. The mean age of subjects was 31.4 years and mean length of service 4.2 years. In the exposed group 48% complained of pain and sensitivity on their teeth compared with the 31% of unexposed persons (P = 0.020). Dental erosion was present in exposed (96%) and unexposed (75%) subjects. Exposed subjects were more likely to develop erosion than unexposed subjects, the odds ratio being 5.531 within the confidence limits 2.167 < OR < 14.117. There was a significant difference in the severity of tooth surface loss between exposed and unexposed groups (P = 0.001). Dental erosion was most severe in the anterior teeth and occurred mostly on the labial and incisal surfaces.