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Biomaterial, Host, and Microbial Interactions
Published in Mary Anne S. Melo, Designing Bioactive Polymeric Materials for Restorative Dentistry, 2020
The total-etch adhesive system involves separate acid-etching and priming/bonding steps (Liu et al. 2011) and can be applied in either a two- or three-step technique, depending on whether the primer and adhesive resin are combined or not (Figures 5.2a and 5.3a) (Delaviz et al. 2014). Acid conditioning is the first step of the etch and rinse technique. In many systems, 37% phosphoric acid is applied to the tooth for 15–30 s in order to demineralize and remove the smear layer. The smear layer is a thin film left on the superficial dentin surface following dental instrumentation that consists of microcrystalline and organic particles and debris (Figure 5.4) (Bortolotto et al. 2009; Delaviz et al. 2014). This is followed by rinsing the acid with water, priming with hydrophilic methacrylate monomers that can prevent collagen collapse by rewetting the dentin, and application of a more hydrophobic methacrylate bonding agent (Delaviz et al. 2014). It was suggested that this process creates a stable resin-tooth interface because the more hydrophobic adhesive resin is able to penetrate and mechanically interlock with the created micropores on the enamel and dentin surface (Nakabayashi et al. 1991).
Influence of the Er,Cr:YSGG laser and radial firing tips on the push-out bond strength of glass fiber posts
Published in J. Belinha, R.M. Natal Jorge, J.C. Reis Campos, Mário A.P. Vaz, João Manuel, R.S. Tavares, Biodental Engineering V, 2019
A.I. Araújo, M. Martins, J.C. Reis Campos, A. Barros, A. Azevedo, T. Oliveira
Moreover, the mechanisms and effectiveness of this wavelength in removing debris and smear layer through cavitational effects (De Moor et al., 2009, De Moor et al., 2010) are consistent with observed morphologic modifications that increased dentinal permeability (Silva et al., 2010). As consequence, it was demonstrated that higher dentinal permeability created by Er,Cr:YSGG laser irradiation could positively influence adhesion of glass ionomer cements (Garbui et al., 2013).
Tooth Whitening Materials
Published in Linda Greenwall, Tooth Whitening Techniques, 2017
Dentin bonding may be altered after whitening (Della Bona et al. 1992) and the smear layer may be removed (Hunsaker et al. 1990). The bonding between glass ionomer and dentin may also be affected (Titley et al. 1991). This may be a result of the precipitate of hydrogen peroxide and collagen that forms on the cut dentin surface after tooth whitening. It is suggested that adhesive dentistry be delayed for 2 weeks after whitening (Powell and Bales, 1991). (See further discussion later.)
The effects of various irrigation protocols on root canal wall adaptation and apical microleakage in primary teeth
Published in Acta Odontologica Scandinavica, 2020
Burcu Nihan Yüksel, Akif Demirel, Meryem Ziya, Kevser Kolçakoğlu, Salih Doğan, Şaziye Sarı
Successful root canal treatment requires complete obturation of the root canal system. Three-dimensional obturation should be provided by the penetration of root canal filling material throughout all the dentinal surfaces of the root canal system [1]. The smear layer which could act as a barrier between the filling material and the canal walls is a layer in the amorphous structure formed due to the mechanical preparation of root canals, composed of inorganic and organic contents [1–4]. Besides the ideal wall adaptation, a tight apical seal is also necessary to obtain successful root canal treatment. In the absence of apical sealing, the bacteria and their by-products that remain persistent in the root canal system may cause reinfection of the root canal system. Many researchers reported the relationship between the presence of the smear layer and the apical microleakage. In the presence of this layer, the penetration of the root canal filling materials to the dentine tubules is limited and an adaptation deficiency between the canal wall and the filling material [1–6]. Therefore, the removal of the smear layer is recommended to reach better clinical results in root canal treatment in primary teeth [1,4,7,8].
The effect of different irrigation protocols on smear layer removal in root canals of primary teeth: a SEM study
Published in Acta Odontologica Scandinavica, 2019
Akif Demirel, Burcu Nihan Yüksel, Meryem Ziya, Hüsniye Gümüş, Salih Doğan, Şaziye Sari
The remaining surface area without instrumentation is significant due to the complex anatomical structure, morphological variations, accessory canals, and ramifications of the root canals of primary molar teeth [2,3]. In addition, the difficulty of hermetic sealing as a result of enlarged apical opening due to physiological root resorption, lack of lateral condensation due to the necessity of using soluble bases because of physiological resorption, and the inability to use pressure-based methods to avoid extension of sealer from the apical foramen lead to additional disadvantages in long-term outcome of root canal treatments [9–11]. Because of these adverse features, although there is no consensus in the literature, the opinion that removal of the smear layer is necessary for the success of endodontic treatment is more common [5].
Evaluation of final irrigation regimens with maleic acid for smear layer removal and wettability of root canal sealer
Published in Acta Odontologica Scandinavica, 2018
Nidambur Vasudev Ballal, Carmen Maria Ferrer-Luque, Mrunali Sona, K. Narayan Prabhu, Teresa Arias-Moliz, Pilar Baca
The present study compared the efficacy of three different final irrigation regimens with MA in removal of canal wall smear layer and their effect on the wettability of epoxy resin-based sealer on root canal dentin surface. Even though previous have demonstrated that the addition of surfactants (CTR) and antiseptics (CHX) to MA increases its antimicrobial efficacy against E. faecalis biofilm [15–17], the results of the present study revealed that, MA alone or MA combined with CTR had better canal wall smear layer removal ability and also reduced the contact angle of AH Plus sealer when compared to MA + CTR + CHX combination. Hence, both the null hypothesis has to be rejected. The poor performance of CHX, when combined with MA and CTR in removal of smear layer and reduction in the contact angle of AH plus sealer may be attributed to the reduced efficacy of CHX to remove the smear layer and decalcify root canal dentin [25,26]. When the smear layer is removed the surface roughness increases due to the opening of the dentinal tubules. Wenzel [27] examined the effect of surface roughness on wetting behaviour and concluded that, the contact angle decreases with the increase of surface roughness. This may be the reason why, MA alone or MA in combination with CTR demonstrated a better smear layer removal and decreased contact angle of AH plus sealer. These results are in accordance with the previous studies which have demonstrated that, irrigation with 7% MA removed canal wall smear layer effectively and increased the surface roughness of root canal dentin [9,28].