Читать книгу Endodontic Materials in Clinical Practice - Группа авторов - Страница 45

Crown discolouration as a result of VPT does not constitute a biological failure of the procedure [219]; however, from the patient’s perspective, it may be of genuine concern. Initially, commercial MTA was available as ProRoot in a grey formulation, which was later superseded by a white product, marketed as being superior in aesthetic areas. For many endodontic applications such as apexification and perforation repair, the discolouration risk of MTA is not critical; however, this is not the case for applications in which the cement in placed in contact with pulp cells in the coronal aspect of the tooth (Figure 2.9). Notably, white ProRoot MTA has also been demonstrated to discolour teeth [135] – a process accentuated in the presence of irrigants such as sodium hypochlorite [223] and fluids like blood [224]. This discolouration has been attributed to the radiopacifier bismuth oxide, which forms a precipitate in the presence of collagen and sodium hypochlorite creating stains [225]. Other hydraulic calcium silicate materials contain other radiopacifiers, including zirconium oxide, which has been linked to a reduced colour change in Biodentine‐treated teeth [226–228]. Tooth discolouration is possible with all HCSCs, particularly in the presence of blood products, but next‐generation materials induce significantly less staining than ProRoot MTA [229], perhaps due to the removal of bismuth oxide. However, radiopacity is often reduced as a result. Interestingly, Biodentine’s radiopacity is consistently reported as being below ISO standards [230, 231], and indeed operators cannot clearly visualize it as distinct to dentine.

Figure 2.9 Discoloured maxillary left lateral incisor one year after a partial pulpotomy procedure using a hydraulic calcium silicate material containing bismuth oxide.

Source: Henry F. Duncan.