Page 16 - SPEMD_60-3

Revista Portuguesa de Estomatologia,
Medicina Dentária e Cirurgia Maxilofacial

rev port estomatol med dent cir maxilofac. 2019;60(3):104-110

Original research

Microhardness and flexural strength after chemical
aging of chlorhexidine delivery systems based

on acrylic resin

b
b,
Cristina Bettencourt Neves , Joana Costa *, Luís Nepomuceno , Ana Madeira ,
a
b
a
Jaime Portugal , Ana Bettencourt c
a Oral and Biomedical Sciences Research Unit (UICOB), Faculdade de Medicina Dentária, Universidade de Lisboa, Lisbon, Portugal
b Faculdade de Medicina Dentária, Universidade de Lisboa, Lisbon, Portugal
c Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Lisbon, Portugal

a r t i c l e i n f o a b s t r a c t

Article history: Objectives: To evaluate the effect of chlorhexidine incorporation on the microhardness and
Received 9 August 2019 flexural strength of three reline acrylic resins, after a 28-day chemical aging process.
Accepted 30 September 2019 Methods: Forty-eight specimens were fabricated according to the several possible combinations
Available online 22 October 2019 of acrylic reline resin and concentrations of incorporated chlorhexidine (Kooliner – 0% vs. 2.5%;
Ufi Gel Hard – 0% vs. 5%; and Probase Cold – 0% vs. 5%), to set 6 experimental groups (n=8).
Keywords: After a 4-week chemical aging process (pH fluctuation in artificial saliva, with cycles of 6 hours
Acrylic resins at pH=3 and 18 hours at pH=7), the Knoop microhardness (98.12 mN, 30 seconds) and flexural
Chlorhexidine strength (1 kN, 5 mm/min) of all specimens were evaluated. Data were submitted to non-par-
Denture relining ametric statistical tests, according to Kruskal-Wallis and Mann-Whitney (α=0.05).
Denture stomatitis Results: Chlorhexidine incorporation did not significantly affect the microhardness of the
Hardness three tested resins (Kooliner – p=0.798; Ufi Gel Hard – p=0.798; and Probase Cold – p=0.195).
Flexural strength Although chlorhexidine incorporation did not influence the flexural strength of Kooliner
(p=0.959) and Ufi Gel Hard (p=0.645), the incorporation of 5% chlorhexidine in Probase Cold led
to a statistically lower flexural strength than that obtained without incorporation (p=0.021).
Conclusion: After chemical aging, the microhardness of chlorhexidine-incorporated acrylic res-
ins is not affected. However, the incorporation of 5% chlorhexidine into Probase Cold negative-
ly affects its flexural strength. (Rev Port Estomatol Med Dent Cir Maxilofac. 2019;60(3):104-110)
© 2019 Sociedade Portuguesa de Estomatologia e Medicina Dentária.
Published by SPEMD. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/).

* Corresponding author.
E-mail address: cristina.neves@fmd.ulisboa.pt (Cristina Bettencourt Neves).
http://doi.org/10.24873/j.rpemd.2019.10.458
1646-2890/© 2019 Sociedade Portuguesa de Estomatologia e Medicina Dentária. Published by SPEMD.
This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).