Читать книгу Endodontic Materials in Clinical Practice - Группа авторов - Страница 28

Regardless of the many years spent researching the ideal restorative material, there is no such thing as a permanent restoration: all have a limited lifetime [73]. As soon as the integrity of a tooth is broken, it must be replaced, setting it on a ‘restorative cycle’ [74]. And each time a restoration is placed, the pulp is made vulnerable and put under threat.

Clinicians carrying out an operative procedure on a vitaI tooth should be mindful of the heat generated by dental handpieces, the potential damage caused by overdehydrating dentine, and the use of caustic agents in tooth restoration, all of which can result in unnecessary iatrogenic pulp damage. Often, prevention is better than cure, so care and attention should be taken when removing tooth tissue and selecting materials to prevent injury to the pulp. The most influential variables in terms of causing injury to the unexposed pulp are considered the cavity's RDT and preparation of the cavity in the absence of coolant [75]. This confirms the observation that excessive heat is the most injurious event to pulp tissue [76]. Other potential sources of pulp injury during restoration of a cavity include etching of the dentin [77] and the choice of restorative material [78].

Any therapeutic process for the benefit of pulp survival that is adopted during the restoration of a tooth with a deep cavity, but unexposed pulp is an indirect pulp cap. Classically, this procedure is carried out when dentine is lost due to caries, trauma, or a previous iatrogenic intervention, and when a cavity exists close to the pulp but dentine remains over the pulp tissue. Indirect pulp capping can be defined as an application of a material on to a thin layer of dentine located close to the pulp with the aim of producing a positive biological response so that the pulp can protect itself.