Connective tissue responses to calcium hydroxide-based root canal medicaments

Aim The objective of the present study was to evaluate the tissue inflammat ory response induced by calcium hydroxide pastes, with or without paramonoc hlorophenol and camphor. Methodology Isogenic BALB/c mice were inoculated into the subcutaneous tiss ue with either 0.1 mL of a suspension of Calen, Calen with camphorated para monochlorophenol, Calen with paramonochlorophenol, Calasept paste or phosph ate-buffered saline (control). After 6, 12 and 24 h and 2, 3, 5, 7 and 15 d ays, three animals in each group were sacrificed and the excised lesions pr ocessed for histopathological evaluation of the inflammatory response. Even ts monitored and graded included the assessment of vascular congestion, oed ema, haemorrhage, inflammatory infiltrate, necrosis and tissue repair. Results The pastes induced an inflammatory response at every observation pe riod, although the intensity, duration and extension of inflammation varied . Calen paste always produced an initial shortterm inflammatory response wh ilst the other pastes produced extended reactions. All pastes allowed repai r to take place by the end of the experimental period, although the speed o f this process varied between the materials. Calen presented the best bioco mpatibility; the phenolic compound caused greater tissue response, which wa s even more severe in the absence of camphor. Calasept paste was damaging a nd the repair process slower. Conclusions All calcium hydroxide formulations caused an inflammatory respo nse. The severity and longevity of the responses varied between pastes as a result of the various antiseptic agents. Although irritating, repair was a pparent with all formulations.