Efficacy of XeCl-308 excimer laser in fusing hydroxyapatite to seal the root apex

Sealing the root apex during apical surgery is important for a successful outcome. The effect of XeCl-308 nm excimer laser irradiation on the fusion and seal of hydroxyapatite to the root apex was tested in extracted human teeth. Twenty-four roots of intact single-rooted premolars were instrumented to size 30 K-file at the apex leaving a patent apical foramen. The apex of each tooth was covered with a freshly prepared paste of hydroxyapatite powder mixed with saline. The samples were then divided into two groups. In 12 teeth, the apical area was irridiated with XeCl-308 nm excimer laser at a fluence of 0.7 J/cm2 for 5 s with pulse repetition rate of 25 Hz and a spot size of 0.13 cm2 immediately after the hydroxyapatite application. In the other 12 teeth, no laser treatment was performed after the hydroxyapatite application. The roots were mounted on a model for the detection of radicular leakage of hydrogen peroxide. The hydrogen peroxide leakage of each sample was measured and the difference between the test groups compared. The ability of the hydroxyapatite plug to prevent hydrogen peroxide leakage at the apex was also tested by applying compressed air from the triple syringe on the coronal access preparation for 2 min. Apical leakage was found in four teeth in the lased group and in eight teeth in the non-plased group. However, the difference between the groups was not statistically significant. Compressed air applied to the coronal access caused hydrogen peroxide leakage in all the teeth.(ABSTRACT TRUNCATED AT 250 WORDS)