Association effect of in-office and nightguard vital bleaching on dental enamel microhardness


  • J.A. Rodrigues State University of Campinas (UNICAMP)
  • Maria Carolina Guilherme Erhardt State University of Campinas (UNICAMP)
  • Giselle Maria Marchi State University of Campinas (UNICAMP)
  • L.A.F. Pimenta State University of Campinas (UNICAMP)
  • Gláucia Maria Bovi Ambrosano State University of Campinas (UNICAMP)



Enamel. Microhardness. Carbamide peroxide. Nightguard vital beaching. In-office bleaching


The aim of this study was to evaluate “in vitro” the microhardness of dental enamel subjected to in-office and nightguard vital bleaching agents: 37% carbamide peroxide-CP37 (Whiteness Super-FGM) and 10% carbamide peroxide-CP10 (Whiteness Perfect-FGM). Enamel fragments measuring 3 x 3mm (n=18) were embedded in polystyrene resin and polished. They were treated 1h once a week with the CP37 and 8h every day with CP10 for 21 days. The remainder of the time they were stored in remineralization solution. Microhardness measurements were completed with a Knoop diamond in a microhardness tester with 50g static load prior to the exposure to bleaching agents and 7, 14, 21, 28, and 35 days after that Split Plot ANOVA followed by Tukey’s test were performed. The test showed no significant differences in the enamel microhardness before, during, or after bleaching treatment. Conclusions: It can be concluded that the combination of in-office and nightguard vital bleaching agents do not alter the enamel microhardness “in vitro”


Download data is not yet available.


Metrics Loading ...

Author Biographies

Maria Carolina Guilherme Erhardt, State University of Campinas (UNICAMP)

Dr. Erhardt has graduated in Dentistry at Universidade Estadual de Campinas - Brazil (1999), got her Master's degree in Dental Clinics - Operative Dentistry at Universidade Estadual de Campinas - Brazil (2003) and her PHd in Dental Clinics - Operative Dentistry at Universidade Estadual de Campinas (2005). Afterwards, was a Postdoctoral fellow at the Universidad de Granada - Spain (2008), focusing her researches in biomaterials in dentistry. Has experience in Dentistry, acting on the following subjects: dentin, bond strength, dental adhesives, microtensile test and microscopic evaluations.

Giselle Maria Marchi, State University of Campinas (UNICAMP)

Possui graduação em Odontologia pela Universidade Estadual de Campinas(1993), mestrado em Clínica Odontológica pela Universidade Estadual de Campinas(1997) e doutorado em Clínica Odontológica pela Universidade Estadual de Campinas(1998).

Gláucia Maria Bovi Ambrosano, State University of Campinas (UNICAMP)

Possui graduação em Engenharia Agronômica pela Universidade de São Paulo (1983), mestrado em Ciências pela Universidade de São Paulo (1987) e doutorado em Ciências pela Universidade de São Paulo (1994).


Haywood VB, Heymann HO. Nightguard vital bleaching. Quintessence Int 1989; 20: 173-6.

Broome JC. At-home use of 35% carbamide peroxide bleaching gel: A case report. Compendium. 1998; 19: 824-8.

Clark DM, Hintz J. Case report; In-office tooth whitening procedure with 35% carbamide peroxide evaluated by the minolta CR-321 chroma meter. J Esthet Dent. 1998; 10: 37-42 4. Kurgel G, Perry RD, Hoang E, Scherer W. Effective tooth bleaching in five days: Using a combined in-office and athome bleaching system. Compendium 1997; 18: 387-83.

Leonard Jr RH, Sharma A, Haywood VB. Use of different concentrations of carbamide peroxide for bleaching teeth: An in vitro study. Quintessence Int. 1998; 29: 503-7.

Bitter NC. A scanning electron microscopy study of the effect of bleaching agents on enamel: A preliminary report. J Prosthet Dent. 1992; 67: 852-5.

Lee CQ, Cobb CM, Zargartalebi BS, Hu N. Effect of bleaching on microhardness, morfology, and color of enamel. Gen Dent. 1995; 158-62.

Mcguckin RS, Babin JF, Meyer BF. Alterations in human enamel surface morphology following vital bleaching. J Prosthet Dent. 1992; 68: 754-60.

Potocnik I, Kosec L, Gaspersic D. Effect of 10% carbamide peroxide bleaching gel on enamel microhardness, microstructure, and mineral content. J Endod. 2000; 26: 203-06.

Seghi RR, Denri I. Effects of internal bleaching on indentation and abrasion characteristics of human enamel in vitro. J Dent Res. 1992; 71: 1340-4.

Rodrigues JA, Basting RT, Serra MC, Rodrigues Jr AL. Effects of 10 percent carbamide peroxide on enamel microhardness at different bleaching times. Am J Dent. 2001; 14: 67-71.

Shanon H. Characterization of enamel exposed to 10% carbamide peroxide bleaching agents. Quintessence Int 1993; 24: 39-44.

Lewinstein I, Hirschfeld Z, Stabholz A, Rotstein I. Effect of hydrogen peroxide and sodium perborate on the microhardness of human enamel and dentin. J Endod. 1994; 20: 61-3.

Lopes GM, Bonissoni L, Baratieri LN, Vieira LCC, Monteiro Jr S. Effect of bleaching agents on the hardness and morphology of enamel. J Esthet Restor Dent. 2002; 14: 24-30.

Featherstone JDB, Ten Cate JM, Shariati M and Arends J. Comparison of artificial caries-like lesions by quantitative microradiography and microhardness profiles. Caries Res. 1983; 17: 385-91.

McCracken M, Haywood VB. Effects of 10% carbamide peroxide on subsurface hardness on enamel. Quintessence int. 1995; 26: 21-4.

Leonard Jr, RH, Austin SM, Haywood, VB, Bentley CD. Change in pH of plaque and 10% carbamide peroxide solution during nightguard vital bleaching treatment. Quintessence Int. 1994; 25: 819-23.

Basting RT, Rodrigues Jr AL, Serra MC. The effect of 10% carbamide peroxide bleaching material on microhardness of sound and demineralized enamel and dentin in situ. Oper Dent, 2001; 26, 531-9.

Attin T, Kielbassa AM, Schwanenberg M, Hellwig E. Effect of fluoride treatment on remineralization of bleached enamel. J Oral Rehab. 1997; 24: 282-6.

Akal N, Over H, Olmez A, Bodur H. Effects of carbamide peroxide containing bleaching agents on the morphology and subsurface hardness of enamel. J Clin Pediatrict Dentistry. 2001; 25(4): 293-6.




How to Cite

Rodrigues J, Erhardt MCG, Marchi GM, Pimenta L, Ambrosano GMB. Association effect of in-office and nightguard vital bleaching on dental enamel microhardness. Braz. J. Oral Sci. [Internet]. 2015 Nov. 12 [cited 2022 Sep. 30];2(7):365-9. Available from:




Most read articles by the same author(s)

1 2 3 > >>