The purpose of this study was to evaluate the effect of light intensity and curing cycle of quartz tungsten halogen (QTH) and plasma arc curing (PAC) lights on the microleakage of class V composite restorations.

A total of 60 freshly extracted human maxillary premolars were used for this study. Standardized class V cavities were prepared and restored with microhybrid resin composite. According to the curing protocol, the teeth were then divided into three groups (n = 20): QTH curing (standard and soft start mode) and PAC high intensity irradiation.

  The microleakage was evaluated by immersion of the samples in 50% silver nitrate solution. The samples were then sectioned, evaluated under a stereomicroscope and scored for microleakage.

Dye leakage scores were obtained, and analysis was done using Student's t-test.

Light curing with QTH light in the soft start mode, showed the least leakage in the composite restoration, which was highly significant when compared with the other groups (p < 0.01). Light curing with QTH light in the standard mode, showed moderate microleakage, which was statistically significant (p < 0.05), when compared with the PAC high intensity curing. Curing with PAC light in high intensity mode resulted in severe microleakage along the cavity margins.

Within the limitations of the study, it may be concluded that:

1. The high intensity PAC light resulted in maximum leakage, when compared to the other groups in the study.

2. The soft start polymerization mode offers a distinctive advantage over the standard curing protocol, in terms of microleakage, for the QTH curing lights.

In the clinical scenario, soft start curing regimen offers a distinctive advantage over the conventional mode of the QTH curing and the high intensity rapid curing offered by the PAC light.

Chandurkar AM, Metgud SS, Yakub SS, Kalburge VJ. Evaluation of Microleakage in Class V Composite Restoration using Different Techniques of Polymerization. Int J Prosthodont Restor Dent 2012;2(1): 10-15.