pôster escola biofotônica valter
TRANSCRIPT
HEAT TRANSMISSION ON DENTIN IRRADIATED BY
Er,Cr:YSGG LASER FOR CARIES PREVENTION
Valter Valentim Lula Júnior1, Profa. Dra. Denise Maria Zezell2, Profa. Dra. Patrícia Aparecida da Ana1 1Universidade Federal do ABC (UFABC) - Av. dos Estados, 5001, Santo André, SP
2Instituto de Pesquisas Energéticas e Nucleares (IPEN) - Av. Lineu Prestes 2242, Cidade Universitária, São Paulo, SP [email protected], [email protected], [email protected]
Advanced School On Modern Trends Of Biophotonics For Diagnosis And Treatment Of Cancer And Microbial Control, April 11 to 19, 2013
Abstract. The temperature changes on root dentin surface and pulp chamber of uniradicular teeth were analysed during Er,Cr:YSGG laser irradiation at low fluences, aiming to determine a promissory parameter for future clinical application for caries prevention in dentin.
Keywords: Er,Cr:YSGG laser, temperature, caries prevention.
INTRODUCTION
Dentin exposure by gingival recession makes teeth more sensible to pain and more
susceptible to caries lesions (Fig. 1).
MATERIAL AND METHODS
Fig. 1 A) Healthy gingiva showing knife-edge border of the free gingiva that is scalloped in shape; B) Gingival recession, with dental root exposure due to gingival margin
migration apical to the cemento-enamel junction (SCHEID and WEISS, 2012).
RESULTS
CONCLUSION
According to the obtained results, the fluence of 2.8 J/cm² can be a promissory parameter
for caries prevention on root dentin.
ACKNOWLEDGMENTS
To IPEN for the laboratorial and CEPOF for the accomodation support.
REFERENCES
ANA, P. A. Estudo in vitro da resistência à desmineralização e da retenção de flúor em esmalte dental irradiado
com laser de Er,Cr:YSGG. 2007. Tese (Doutorado) Instituto de Pesquisas Energéticas e Nucleares, São Paulo.
SCHEID, R. C.; WEISS, G. Woelfel's Dental Anatomy. 8. ed. Philadelphia: LWW, 2012.
ZACH, L.; COHEN, G. Pulp response to externally applied heat. Oral Surg., v. 19, n. 4, p. 515-30, 1965
Gingival recession Root and dentinal tubules exposure
Severe root caries and hypersensitivity
Hi-power laser heating
(Fig. 2)
Chemical changes in dentin (Fig. 3)
Risk of pulpal damage
Dentin surface and pulpar chamber heating analysis
Safe and effective parameters for
caries prevention X
Fig. 2 Absorbance spectrum of the main componentes of biological tissues, related to the main laser wavelenghts used in dentistry.
(ANA, 2007).
Fig. 3 Chemical changes in dental hard tissues after laser heating. According to the temperature, it is possible to note changes in water, carbonate and organical material content, as well as the transformation of phosphate in pirophosphate, increase of
hydroxyl and formation of new crystallographic phases, which leads to decrease of acid solubility (ANA, 2007).
20 incisor human teeth
Pulp removal
Opening of teeth lingual surfaces
Placing of thermocouple (Fig. 4)
10 teeth in group A
10 teeth in group B
Group A: 2,8 J/cm2
Group B: 5,6 J/cm2
Er,Cr:YSGG pulsed laser irradiation for
20s
Thermocouple and thermographic camera heat analysis (Fig. 5)
Statistical analysis (Table 1)
Fig. 4 Thermocouple placing.
Fig. 5 Root dentin irradiation.
Fig. 5 Infrared images during radicular dentin irradiation; a) at beginning, b) during irradiation; c) imediatelly after irradiation; d) during tooth cooling.
Fig. 6 Surface temperature changes during Er,Cr:YSGG laser irradiation at
2.8 J/cm2.
Fig. 7 Pulpal temperature changes during laser irradiation detected with
thermocouple
Dentin surface temperature data evidences
Er,Cr:YSGG laser potential on trigger chemical
changes in dentin when irradiated with 5.6
J/cm² fluence, due to temperature raises
above 100°C. Nevertheless, even with less
chemical changes due to lower temperature
raises, 2.8 J/cm² fluence suggests to be more
indicated because it was not induced
intrapulpal temperature raises higher than
5.5°C, without pulpal damage risk (ZACH and
COHEN, 1965).
Laser
Thermocouple
Thermographic camera
Tooth
Dental wax
0 20 40 60 80 100
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
T
(o C
)
Time (s)
2.8 J/cm2
5.6 J/cm2
0 20 40 60 80
20
30
40
50
60
70
Te
mp
era
ture
(o C
)
Time (s)
2.8 J/cm2