The effect of nano‑hydroxyapatite and casein phosphopeptide‑amorphous calcium phosphate with and without laser irradiation on the microhardness and surface morphology of demineralized primary enamel: An in vitro experimental study

Abstract

Background: Various topical gels, varnishes, and fluoride gels are being used by dentists
for the treatment of White spot lesions (WSLs). The remineralizing effect of casein
phosphopeptide‑amorphous calcium phosphate (CPP‑ACP), nano‑hydroxyapatite (nHAp), and lasers
has been proven earlier. This study was designed to evaluate the remineralizing effect of nHAp and
CPP‑ACP with and without erbium‑doped yttrium aluminum garnet (Er: YAG) laser irradiation on
demineralized primary enamel.
 The aim of this study was to evaluate the effect of CPP‑ACP and nHAp with and without
Er:YAG laser irradiation on the microhardness and surface morphology of demineralized primary
enamel.
Materials and Methods: The present study is an experimental in vitro study. Fifty extracted primary
incisors were selected for the study. Following cleaning and sectioning, teeth were embedded
in acrylic. The tooth models were divided into four groups randomly – Group 1 (CPP‑ACP),
Group 2 (nHAp), Group 3 (CPP‑ACP + laser), and Group 4 (nHAp + laser). The baseline,
postdemineralization, and postremineralization Vickers hardness testing was performed. One
sample from each group was analyzed by scanning electron microscopy. Descriptive statistics such
as frequencies and percentages for categorical data, mean and standard deviation for numerical
data were depicted. The normality of numerical data was checked using the Shapiro–Wilk test. The
level of significance was kept at 5%. Intergroup comparison (>2 groups) was done using one‑way
analysis of variance followed by pair‑wise comparison using the post hoc test.
Results: There was a statistically significant increase in surface microhardness in each group after
remineralization. The highest increase in microhardness value was seen in Group 4 (nHAp + laser)
followed by Group 3 (CPP‑ACP + laser) and the least in Group 1 (CPP‑ACP). Similar observations
were made in scanning electron microscopic images. This indicated that nHAp has a comparable,

if not better ability for remineralization than CPP‑ACP. The remineralizing capacity of both the
remineralizing agents was seen to be improved in this study when simultaneous laser application
was employed.
Conclusion: Currently, the evidence supporting the efficacy of nHAp dentifrices and laser in
primary teeth is limited. Additional long‑term in vivo studies employing standardized protocols
and large sample sizes are necessary to draw definitive findings about the effect of remineralizing
agents and lasers on primary enamel.
Key Words: Deciduous teeth, hydroxyapatite, laser, tooth remineralization

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 Anil Tanaji Patil: Pubmed,Google Scholar