Removing Carious Tissue: Why and How?

Caries is no longer seen as an infectious disease, and the aim of treating carious lesions is to control their activity, not to remove the lesion itself. Such control can be implemented by sealing off the lesion from the environment, with sealed bacteria being deprived from carbohydrates and thus inactivated. For cavitated lesions, controlling them usually involves the placement of restorations to rebuild the cleansability of the surface. In this case, dental practitioners have traditionally removed carious tissues prior to the restoration. This has historically been for a number of reasons, while today the main reason for restoring a cavity is to maximise restoration longevity. In shallow lesions, dental practitioners should aim to remove as much carious tissue as possible (to allow adequate depth for the restorative material) without unnecessarily removing sound or remineralisable dentine. This means removal to hard dentine around the periphery, to firm dentine centrally for optimising restoration longevity and allowing a tight cavity seal. For deep lesions in teeth with vital pulps (without irreversible pulpitis), maintaining pulp vitality is critical. Dental practitioners should aim to avoid pulp exposure, leaving soft or leathery dentine in pulpoproximal areas. Peripherally, hard tissue is left, again to ensure a tight seal and sufficient mechanical support of the restoration. As an alternative to the selective removal to soft dentine, stepwise removal can be used. With this approach, the soft dentine is temporarily rather than permanently sealed in, and removed in a second step after 6-12 months. Strategies where carious tissue in cavitated lesions is not removed at all, but sealed or managed non-restoratively, are currently restricted to primary teeth.