Abstract:
Background: The aim of this study was to evaluate the effect of combining fractional CO2 LASER and nanohy-
droxy apatite on surface microhardness and color of enamel with initial defects.
Material and Methods: Two types of nano hydroxylapatite (nHAP) was prepared; Pure hydroxyapatite (nHA) and
Fluoro hydroxyapatite (nFHA), Sixty extracted premolar teeth without visible caries or structural defects on enamel
surface were used, immersed in 10 ml of a demineralizing solution for 2 weeks to create artificial white spot lesions,
they were randomly allocated into two groups; Group 1: nHA, Group 2: nFHA, each group is then subdivided into
2 subgroups (A and B) where two different in vitro remineralization procedures have been performed, the first
procedure utilizes a 10wt% nHA aqueous slurries only, the second was first exposed to irradiation from a fractional
CO2
laser then (nHAP) was applied. Microhardness and color were measured using a micro-Vickers hardness tester
and spectrophotometer respectively.
Results: Laser treated teeth in both groups showed the highest mean hardness and lowest color difference where
ΔE was less than 3.3 units, in both tests the pure type of nanohydroxyapatite gave better results than the nanoflu-
roapatite type.
Conclusions: Nano-hydroxyapatite has remarkable remineralizing effects on initial lesions of enamel, certainly
higher when combined with laser application.
