The influence of pH cycling period on the formation of white spot lesions and microleakage

ABSTRACT

The objective of this study was to assess the influence of pH cycling on the formation of white spot lesions (WSL) and on microleakage (ML). Standart preparations were made in 54 bovine teeth (B). Next B was divided into 3 groups (G) G1 - TPH; G2 - Vitremer; G3 - Freedom. Half a sample from each Group G (n = 9) was analyzed after 7 days of pH cycling (T1), and the other half after 14 days (T2). The formation of WSL was assessed according to the scale 0 - Absence WSL, 1 - WSL < 50%, 2 - 50% < WSL < 100%, 3 - WSL = 100%. ML was assessed considering 0 - Absence, 1 - ML > 1/2 of gingival wall, 2 - ML > 1/2 of gingival wall without reaching the axial wall, 3 - ML involving axial wall. Regarding WSL, G3 > G1 > G2 was observed both in T1 and T2 (p < 0.01). With regard to ML, T1 G1 > G3 > G2 (p < 0.01) and T2 G1 > G2 > G3 (p < 0.01) were found. The periods of time in which the teeth were submitted to pH cycling was also a factor which influenced the formation of WSL and ML.