Influence of radiotherapy on the dentin properties and bond strength

Abstract

RT causes changes that contribute to increased risk of tooth decay. Restorative treatments can be performed using adhesive procedures, but it is preferable to be performed before of the irradiation protocol, to guarantee better adhesive properties to restoration.

Effect of carbodiimide and chlorhexidine on the bond strength longevity of resin cement to root dentine after radiation therapy

“…Radiotherapy has a semi‐selective character, and the surrounding tissues are not always preserved (Roś‐Mazurczyk et al ) causing side effects in the oral cavity, including radiation carious lesions (Lieshout & Bots , Gupta et al , Dobroś et al , Qing et al ), which can cause severe tooth destruction, leading these patients to seek functional and aesthetic restorations. Recent studies have shown that in these cases, the longevity of adhesive restorations is compromised (Naves et al , Rodrigues et al , Yamin et al ), confirming the importance of establishing clinical protocols that provide satisfactory dental treatments, thus improving the patient’s quality of life.…”

“…Radiotherapy X‐rays act in the presence of water through the formation of free radicals and hydrogen peroxide (Cole & Silver , Fisher et al ), capable of acting as a strong oxidant, causing the denaturation and fragmentation of the dentine collagen fibres network (Pioch et al , Aggarwal , Kochueva et al , Gonçalves et al , Qing et al ), besides activating metalloproteinases (Strup‐Perrot et al , Mcguire et al ). Thus, the degradation of the collagen fibre network is probably related to the lower bond strength values of the resin cement to root dentine observed in the irradiated teeth (Aggarwal , Rodrigues et al , Yamin et al ), as well as in the greater mismatch of the adhesive interface observed in SEM (Figs and ) (Gonçalves et al , Lieshout & Bots ), since the RelyX U200 resin cement bonding mechanism is promoted by acid monomers that, when interacting with the organic part of the resin cement and with the root dentine, demineralize and penetrate the dentine, creating micromechanical retention and chemical bonding to the hydroxyapatite. It does not depend on hybrid layer formation or presence of tags (Ferracane et al ), but rather of an ionization medium for the chemical reaction to occur (Mushashe et al ), which when altered by irradiation may have led to a lower number of chemical bonds between the cement and root dentine (Yamin et al ).…”

“…the degradation of the collagen fibre network is probably related to the lower bond strength values of the resin cement to root dentine observed in the irradiated teeth (Aggarwal 2009, Rodrigues et al 2018, Yamin et al 2018, as well as in the greater mismatch of the adhesive interface observed in SEM (Figs 2 and 3) (Gonc ßalves et al 2014, Lieshout & Bots 2014, since the RelyX U200 resin cement bonding mechanism is promoted by acid monomers that, when interacting with the organic part of the resin cement and with the root dentine, demineralize and penetrate the dentine, creating micromechanical retention and chemical bonding to the hydroxyapatite. It does not depend on hybrid layer formation or presence of tags (Ferracane et al 2011), but rather of an ionization medium for the chemical reaction to occur (Mushashe et al 2016), which when altered by irradiation may have led to a lower number of chemical bonds between the cement and root dentine (Yamin et al 2018).…”

“…It has been reported that radiotherapy of the head and neck region is associated with alterations in mineralized dental tissues such as: enamel and dentine disorganization (Gonc ßalves et al 2014, Rodrigues et al 2018, reduction of amelodentinal junction stability (Pioch et al 1992), changes in peptide chains and dehydration of collagen fibres (Kochueva et al 2012, Gonc ßalves et al 2014, increased expression of metalloproteinases (Mcguire et al 2014), obliteration of dentinal tubules due to the degeneration of odontoblastic processes (Gonc ßalves et al 2014), change in chemical composition (Qing et al 2016, Velo et al 2018, increased solubility (Markitziu et al 1986), as well as reduction of dentine microhardness (Gonc ßalves et al 2014, Qing et al 2016, Velo et al 2018. Head and neck cancer patients are routinely submitted to dental evaluation and treatments, such as tooth extraction, endodontic, restorative and periodontal therapies (Vissink et al 2003) However, the healthy teeth retained in the oral cavity, that do not have an initial risk of infection, can be affected by the alterations mentioned above which, associated with xerostomia and the difficulty of adequate oral hygiene (due to the development of mucositis and muscular rigidity), can result in the occurrence of radiation carious lesions.…”

Effect of the double application of universal adhesives on the dentine bond strength after radiotherapy

“…8 The changes to the organic portion of the dentine can also interfere with the bond strength of adhesive procedures. 9,[12][13][14][15][16][17] The negative effects of radiotherapy on the bond strength also be attributed to impairing the hybrid layer formation by denaturation of the organic components of dentine structures. 8,9,12,17,18 It is well-known that the hybrid layer plays an important role in the adhesion mechanism between the dentine and adhesive resin.…”