title: Thermal effects and morphological aspects of varying Er:YAG laser energy on demineralized dentin removal: an in vitro study.
abstract: The aim of this study was to evaluate thermal changes, dentin ablation removal capacity, and morphological aspects of sound and demineralized human dentin surface irradiated with different output energies of an erbium: yttrium-aluminium-garnet (Er:YAG) laser. Eighty sound human tooth specimens were assigned into two groups: demineralized dentin and sound dentin (control group). The dentin groups were subdivided into four subgroups (n = 10) according to the irradiation energy used (120, 160, 200, or 250 mJ) at a constant frequency level of 6 Hz, in focused mode, and under refrigeration. Quantitative analysis of the sound and carious dentin ablation was performed using light microscopy (LM) by measuring (mm) the remaining demineralized tissue with the Axion Vision™ software. Qualitative analysis was performed using the images obtained with a scanning electron microscope (SEM), and the temperature increase was recorded with an infrared digital thermometer. The Er:YAG laser promoted a gradual increase in temperature for all groups, and no difference was observed between the sound and demineralized dentin. The groups of 200 and 250 mJ showed the highest values, yet a variation in temperature did not exceed 5 °C. The energy output of 120 mJ selectively removed demineralized tissue when compared to 250 mJ, while also providing more regular surfaces in the cavity preparation. It was concluded that the temperature increase during sound and demineralized dentin removal had a strong positive correlation with the Er:YAG laser energy level output. However, the higher energies used did not present selectivity to the demineralized tissue, and the parameters used did not cause an increase in temperature over 5 °C.
authors.affiliation: School of Dentistry, University of Ribeirão Preto-UNAERP, Avenida Constábile Romano, Ribeirão Preto, SP, CEP 14096-900, Brazil.
authors.forename: Walter
authors.initials: W
authors.lastname: Raucci-Neto
authors.forename: Carla
authors.initials: C
authors.lastname: Raquel Dos Santos
authors.forename: Fabrício
authors.initials: F
authors.lastname: Augusto de Lima
authors.forename: Jesus Djalma
authors.initials: JD
authors.lastname: Pécora
authors.forename: Luciano
authors.initials: L
authors.lastname: Bachmann
authors.forename: Regina Guenka
authors.initials: RG
authors.lastname: Palma-Dibb
mesh_terms: D003731:Dental Caries / Q000473:pathology / Q000601:surgery; D003737:Dental Cavity Preparation / Q000379:methods*; D003804:Dentin / Q000528:radiation effects; D006358:Hot Temperature; D006801:Humans; D053685:Laser Therapy; D053844:Lasers, Solid-State
references.citation: Microsc Res Tech. 2012 Oct;75(10):1370-5
references.pmid: 22648790
references.citation: Br Dent J. 2008 Jul 12;205(1):E1; discussion 28-9
references.pmid: 18535534
references.citation: Photomed Laser Surg. 2013 May;31(5):201-5
references.pmid: 23480272
references.citation: Lasers Surg Med. 2003;32(1):25-31
references.pmid: 12516067
references.citation: Aust Dent J. 2006 Jun;51(2):162-9
references.pmid: 16848265
references.citation: Microsc Res Tech. 2011 Mar;74(3):281-6
references.pmid: 20623778
references.citation: Lasers Surg Med. 2004;34(3):254-9
references.pmid: 15022253
references.citation: Lasers Surg Med. 2008 Jul;40(5):350-7
references.pmid: 18563782
references.citation: Dent Clin North Am. 2000 Oct;44(4):931-53, viii
references.pmid: 11048281
references.citation: J Endod. 2000 Mar;26(3):138-41
references.pmid: 11199705
references.citation: Quintessence Int. 1992 Feb;23(2):143-7
references.pmid: 1641453
references.citation: J Clin Laser Med Surg. 1999 Jun;17(3):105-9
references.pmid: 11199828
references.citation: J Dent Res. 1977 Oct;56(10):1233-7
references.pmid: 272387
references.citation: Photomed Laser Surg. 2005 Apr;23(2):182-6
references.pmid: 15910183
references.citation: Lasers Med Sci. 2010 May;25(3):317-24
references.pmid: 18982403
references.citation: J Clin Laser Med Surg. 1998 Oct;16(5):273-82
references.pmid: 9893509
references.citation: J Contemp Dent Pract. 2012 Jan 01;13(1):40-7
references.pmid: 22430692
references.citation: J Dent. 2004 Jan;32(1):35-40
references.pmid: 14659716
references.citation: Photomed Laser Surg. 2013 Mar;31(3):116-24
references.pmid: 23421630
references.citation: Photomed Laser Surg. 2008 Jun;26(3):189-95
references.pmid: 18588434
references.citation: Photomed Laser Surg. 2007 Aug;25(4):281-6
references.pmid: 17803385
references.citation: Lasers Med Sci. 2008 Oct;23(4):435-41
references.pmid: 17963019
references.citation: Scanning Microsc. 1993 Sep;7(3):989-97
references.pmid: 8146625
references.citation: Caries Res. 2006;40(2):117-23
references.pmid: 16508268
references.citation: Lasers Med Sci. 2012 Jan;27(1):1-5
references.pmid: 20737181
references.citation: Caries Res. 1982;16(3):201-10
references.pmid: 6953998
references.citation: Compend Contin Educ Dent. 2003 Nov;24(11):837-8, 841, 843 passim; quiz 848
references.pmid: 18624131
references.citation: J Clin Laser Med Surg. 2003 Jun;21(3):139-44
references.pmid: 12828848