This study evaluated the effect of chopped carbon dioxide (CO2) laser irradiation on caries prevention in deciduous enamel. 24 extracted deciduous molars were irradiated with chopped CO2 laser using different parameters and immersed in acid to produce lesions. Lesion depths were measured and compared to a control group. Chopped CO2 laser irradiation significantly increased caries resistance in deciduous enamel by up to 76%, with higher energy densities and longer pulse durations decreasing the level of caries inhibition. The results suggest that chopped CO2 laser irradiation enhances deciduous enamel resistance to caries and optimal parameters should be used.

1. Enhancement of Caries
Inhibition of the Deciduous
Enamel by Using Chopped
Carbon Dioxide Laser
Prof Muthenna Shaban Rajab
Tikrit University /College of Dentistry

2. Main problem
Dental caries
continues to be a
major dental
disease of human
beings.
Dental caries is the
most prevalent
chronic disease of
childhood.

3. • One of the main roles
of pediatric dentistry is
the prevention in
order to reduce the
incidence of dental
caries throughout
childhood.
• Fluoride is the most
powerful treatment to
prevent tooth caries.

4. • The idea and concept
of laser capability
was first
acknowledged in
1917.
• Maiman developed
the ruby laser in
1960

5. • lasers have been tested to
improve dental enamel
properties in order to
enhance its resistance to
demineralization.
• CO2 laser irradiation can
decrease permanent
enamel demineralization.
• The effect of laser on
deciduous enamel
resistance to caries was
seldom studied.
• It is the first time to use
chopped CO2 laser on
deciduous teeth.

6. Goals and Objectives
The aim of the current study is to evaluate
the potential of chopped CO2 laser for
caries prevention of deciduous enamel, and
to obtain the optimum laser parameters
which serving this purpose.

7. 24 extracted deciduous molars
stored in distilled water at
4ºC.
Painted with acid resistant
varnish leaving 2-4mm
windows buccaly and
lingually.
Materials and Methods

8. Table (1): Experimental groups and related chopped CO2 laser parameters.
Materials and Methods
The samples were
irradiated by using
chopped CO2 laser (BLITZ
50 SV, as a medical laser,
Vicenza, Italy) with 10.6
µm wavelength.

9. Experimental groups and related chopped CO2 laser parameters.

10. • samples were immersed in lactic
acid solution with 3.5 pH and
incubated at 37ºC for 21 days to
produce caries like lesion.
• cross sections were made through
the buccal and lingual windows,
and microscopical slides were
prepared to be examined under
polarizing microscope (Zeiss,
Germany).
• Lesion depths were measured and
caries inhibition percentages were
estimated.
Materials and Methods

11. Results
experimental lesion depth control lesion depth
P-value
Significance
(P> 0.05)
group mean SD mean SD
A1
171 9.0
592 9.8
1.48536E-06 s
A2
277 17.1 2.28723E-05 s
A3
420 21.2 0.000482098 s
B1
144 9.0 1.15882E-06 s
B2
348 22.9 0.000156513 s
B3
420 21.2 0.000482098 s
C1
189 17.1 8.58088E-06 s
C2 331 10.6 1.3932E-05 s
C3 420 21.2 0.000482098 s
Lesion depths of experimental groups in relation to control group.

12. Results
Figure (1): Polarizing microscopic images of the control group (a) and
group B1 (b).

13. Discussion
Chopped carbon dioxide laser irradiation
results in a significant increase in caries
resistance of deciduous enamel.

14. Inverse relationships were
observed between the
energy density of the laser
beam and the caries
inhibition percentages
In high energy density,
deciduous enamel showed
melting and fusion, and
formation of some cavities
with variable sizes.*
*MR De Souza 2009
Group Parameters CI %
Group A No. of Pulses ED (J/cm2)
A1 2 25.47 71
A2 4 50.93 53
A3 8 101.86 29
Group B Pulse Duration (s) ED (J/cm2)
B1 0.002 25.47 76
B2 0.004 50.93 41
B3 0.008 101.86 29
Group C Spot Diameter (mm) ED (J/cm2)
C1 4 25.47 68
C2 2.83 50.93 44
C3 2 101.86 29
Control ---- ---- 0
Discussion

15. In group A, number of
pulses affects the
caries inhibition
percentages inversely.
Group Parameters CI %
Group A No. of Pulses ED (J/cm2)
A1 2 25.47 71
A2 4 50.93 53
A3 8 101.86 29
Group B Pulse Duration (s) ED (J/cm2)
B1 0.002 25.47 76
B2 0.004 50.93 41
B3 0.008 101.86 29
Group C Spot Diameter (mm) ED (J/cm2)
C1 4 25.47 68
C2 2.83 50.93 44
C3 2 101.86 29
Control ---- ---- 0
Discussion

16. Increase the pulse
duration in group B
decreased the caries
inhibition percentages.
Group Parameters CI %
Group A No. of Pulses ED (J/cm2)
A1 2 25.47 71
A2 4 50.93 53
A3 8 101.86 29
Group B Pulse Duration (s) ED (J/cm2)
B1 0.002 25.47 76
B2 0.004 50.93 41
B3 0.008 101.86 29
Group C Spot Diameter (mm) ED (J/cm2)
C1 4 25.47 68
C2 2.83 50.93 44
C3 2 101.86 29
Control ---- ---- 0
Discussion

17. The spot diameter had
direct relationship
with caries inhibition
percentage in group C.
Group Parameters CI %
Group A No. of Pulses ED (J/cm2)
A1 2 25.47 71
A2 4 50.93 53
A3 8 101.86 29
Group B Pulse Duration (s) ED (J/cm2)
B1 0.002 25.47 76
B2 0.004 50.93 41
B3 0.008 101.86 29
Group C Spot Diameter (mm) ED (J/cm2)
C1 4 25.47 68
C2 2.83 50.93 44
C3 2 101.86 29
Control ---- ---- 0
Discussion

18. • Similar finding were found using argon,
Nd:YAG, and CW CO2 lasers on deciduous
enamel.
• Chopped CO2 laser found to produce similar
effects on permanent enamel.
• This is the first study used chopped CO2
laser on deciduous enamel.

19. Conclusion
• Chopped carbon dioxide laser irradiation results
in a significant increase in caries resistance of
deciduous enamel. This enhancement of
deciduous enamel reaches as high as 76%.
• Increasing the energy density leads to decrease
the caries inhibition percentage.
• Maximum caries inhibition percentage found to
be related to the shortest pulse duration of the
chopped carbon dioxide laser.

20. Good teeth means good smile