Dentin Microhardness and Sealer Bond Strength to Root Dentin are Affected by Using Bioactive Glasses as Intracanal Medication.

Renata Grazziotin-Soares,Meire Coelho Ferreira,Bruna Lais Lins Gonçalves,Letícia Gomes Dourado,Ceci Nunes Carvalho,José Bauer,Diego Machado Ardenghi

doi:10.3390/ma13030721

Renata Grazziotin-Soares, Meire Coelho Ferreira + Show 5 more

Open Access

https://doi.org/10.3390/ma13030721

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Abstract

This study investigated the human dentin microhardness (MH) and the MTA Fillapex® (Fillapex) and AH Plus®(AH) bond strength (BS) to dentin after using calcium hydroxide (Ca(OH)2) and bioactive glasses (45S5 and an experimental niobium phosphate bioactive glass (NbG)) as intracanal medications. For the MH test dentin slices were filled with medications and were submitted to Knoop MH (KHN) test (at day-0 (baseline data/without medication) and at day-15 (after using medication)). For the BS test, after medications had remained for 15 days in the roots, dentin slices were obtained and filled with the sealers. Seven days later, sealer BS to dentin was measured by push-out test (MPa). Data were statistically analyzed. Failure mode was visually assessed. The use of NbG, 45S5 for 15 days, increased the dentin MH and reduced the BS between AH sealer and dentin, but did not interfere with the Fillapex BS.

Highlights

In vitro studies have shown that using the intracanal medication calcium hydroxide (Ca(OH)2 )negatively affects dentin properties, for instance, the dentin microhardness [1,2], and the root fracture resistance of extracted teeth [3,4]
Considering the possibility to have an intracanal medication that acts in favor of mechanical properties of either dentin or root canal sealers, this present study focused on two different bioactive glasses used as intracanal medications: one commercially available (45S5) and the other an experimental composition (NbG)
niobium phosphate bioactive glass (NbG) and 45S5 induced an increase in the dentinal MH of 37.7% and

Summary

Introduction

Negatively affects dentin properties, for instance, the dentin microhardness [1,2], and the root fracture resistance of extracted teeth [3,4]. This weakening effect in dentin is associated with the reported. The presence of remaining particles of Ca(OH) attached to the canal walls might affect the sealer setting [6]. This would increase the likelihood of filling material dislodgment, microbial (re)contamination and percolation of fluids from the coronal and apical paths [7]. Bioactive glass has antimicrobial effects in closed systems [11] and differently than calcium hydroxide, the antibacterial efficacy of bioactive glass increases when it is Materials 2020, 13, 721; doi:10.3390/ma13030721 www.mdpi.com/journal/materials

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Discussion

Conclusion