The effect of dental bleaching on pulpal tissue response in a diabetic animal model.
OBJECTIVE
To evaluate pulpal tissue response after dental bleaching in normal and alloxan-induced diabetic rats.


METHODS
Twenty-eight rats were divided into two groups of normoglycaemic and diabetic rats (n = 14). Diabetes mellitus (DM) was induced with alloxan. After DM confirmation, all rats were anaesthetized and dental bleaching was performed with 35% hydrogen peroxide (H2O2) on the right maxillary molars for 30 min. Left molars were used as controls. Bleaching resulted in four hemimaxillae groups: normoglycaemic (N), N-bleached (NBle), diabetic (D) and D-bleached (DBle). After 2 or 30 days, the animals were euthanized and the hemimaxillae were removed, processed for histopathological analysis and stained with haematoxylin-eosin (HE), Masson's trichrome (MT) and picrosirius red (PSR). Results obtained within animals (normoglycaemic or diabetic rats) were submitted to Wilcoxon or paired t-tests, and between animal (normoglycaemic and diabetic rats), to Mann-Whitney test or t-tests.


RESULTS
At 2 days, the NBle group had a mild inflammatory infiltration in the pulpal tissue, whilst the DBle had severe inflammation or necrosis (P < 0.05). At 30 days, no inflammation was present. However, a significant difference in pulp chamber area reduction by reactionary dentine deposition was found between the NBle and DBle groups (P < 0.05). At 2 days, fewer immature collagen fibres and more mature collagen fibres were noted in the NBle, D and DBle groups; this was significantly different when compared to the N group (P < 0.05). At 30 days, significantly fewer immature collagen fibres and more mature collagen fibres were noted in NBle compared with DBle group (P < 0.05).


CONCLUSIONS
The inflammatory tissue response in rats' teeth after dental bleaching was greater in diabetic rats. Additionally, the increase in reactionary dentine deposition and mature collagen fibres observed in diabetic rats needs further evaluation to confirm the present results.
Departments of Endodontics, Araçatuba Dental School, Unesp - Univ Estadual Paulista, Araçatuba, SP, Brazil.
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http://orcid.org/0000-0003-2348-7846
LTA
Cintra
Departments of Endodontics, Araçatuba Dental School, Unesp - Univ Estadual Paulista, Araçatuba, SP, Brazil.
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Ferreira
Departments of Endodontics, Araçatuba Dental School, Unesp - Univ Estadual Paulista, Araçatuba, SP, Brazil.
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Benetti
Centro de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara, JAL, México.
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Gastélum
Departments of Endodontics, Araçatuba Dental School, Unesp - Univ Estadual Paulista, Araçatuba, SP, Brazil.
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Gomes-Filho
Department of Basic Science, Araçatuba Dental School, Unesp - Univ Estadual Paulista, Araçatuba, SP, Brazil.
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Ervolino
Department of Restorative Dentistry, Araçatuba Dental School, Unesp - Univ Estadual Paulista, Araçatuba, SP, Brazil.
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Briso
D000818:Animals; D003786:Dental Pulp Cavity / Q000473:pathology*; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D006861:Hydrogen Peroxide / Q000009:adverse effects*; D008297:Male; D009336:Necrosis / Q000139:chemically induced; D011671:Pulpitis / Q000139:chemically induced*; D017208:Rats, Wistar; D058205:Tooth Bleaching Agents / Q000009:adverse effects*
D058205:Tooth Bleaching Agents; D006861:Hydrogen Peroxide
collagen; dental bleaching; inflammatory response; reactionary dentine