The Impact of CO2 Laser and Hydroxyapatite Nano Particles on Dental

Abstract: Background: Laser technology holds great promise for medical and dental applications and carbon dioxide (CO2) laser is
still one of the most beneficial type. A laser beam is created from a substance known as an active medium, which when stimulated by
light or electricity produces photons of a specific wavelength. This beam results in an interaction between light and biological
constituents of tissues that are converted into heat; ending with structural and chemical changes in tissues. Dental caries is a dietary
carbohydrate-modified bacterial infectious disease. The basic mechanism of dental caries is demineralization through the acids attack.
Lasers are expected to be one of the most promising new technical modalities for the treatment of dental diseases. Nanotechnology is
“the manipulation of matter on the molecular and atomic levels. The developed interest for nanotechnology in many fields, is producing
interesting and imminent applications as tissue repair and replacement especially in bones and dental mineralized tissues. Aim of the
study: this study was conducted to test the impact of CO2
laser and Hydroxyapatite nanoparticles on the change in chemical composition
of enamel and the morphological changes in enamel ultra-structure. Materials and Methods: Teeth samples in this study consisted of 66
maxillary first premolars, divided into six groups: one control group and five study groups, each group consisted of 11 teeth; one tooth
for Scanning Electron Microscope examination (SEM), while other 10 teeth for Energy dispersive spectroscopy (EDS) analysis.A
position of circular window on the buccal surface of each tooth was standardized. To induce caries lesion on enamel surface, pH cycling
procedure was followed. Lasing was carried out using CO2 laser system at specific power, time and mode. Hydroxyapatite nanoparticles
used in the study was 20nm, the concentration was determined to be 10%. The weight percentages (wt%) of Calcium, Phosphorus,
Oxygen were determined using EDS analysis to evaluate the change in chemical composition of enamel; SEMwas used to demonstrate
the morphological changes in enamel ultra-structure. Results: For all groups, the data obtained by (EDS) analysis revealed that for both
Calcium (Ca) and Phosphorus (P), the mean atomic percentage was reduced after demineralization and after laser irradiation. An
increase in the atomic percentage for both elements after treatment with other agents was noticed, with the maximum value recorded for
the group treated with Laser + hydroxyapatite nanoparticles. For Oxygen (O), the result was opposite to that of (Ca) and (P). Statistical
analysis werehighly significant (p>0.01) for all of the three elements. Examination of enamel surface using SEM revealed an
ultrastructural change had occurred beginning with loss of enamel normal architecture after demineralization. After CO2 laser
irradiation, cracks and melted and recrystallized areas were noticed. After treatment with hydroxyapatite nanoparticles, hydroxyapatite
nanoparticles + CO2 laser and CO2 laser + hydroxyapatite nanoparticles most of micropores were occluded and surface defects were
reconstructed. Conclusion: Treatment of enamel surface with CO2 laser + hydroxyapatite nanoparticles gave the best result regarding
EDS analysis and SEM examination, so such treatment could be considered as a method of preventing demineralization and
encouraging remineralization of enamel.
Keywords: CO2 laser, hydroxyapatite nanoparticles, EDS analysis, SEM examination