Present status and future directions: The restoration of root filled teeth

Abstract

This narrative review will focus on a number of contemporary considerations relating to the restoration of root filled teeth and future directions for research. Clinicians are now more than ever, aware of the interdependence of the endodontic and restorative aspects of managing root filled teeth, and how these aspects of treatment are fundamental to obtaining the best long-term survival. To obtain the optimal outcomes for patients, clinicians carrying out endodontic treatment should have a vested interest in the restorative phase of the treatment process, as well as an appreciation for the structural and biomechanical effects of endodontic-restorative procedures on restoration and tooth longevity. Furthermore, the currently available research, largely lacks appreciation of occlusal factors in the longevity of root filled teeth, despite surrogate outcomes demonstrating the considerable influence this variable has. Controversies regarding the clinical relevance of minimally invasive endodontic and restorative concepts are largely unanswered with respect to clinical data, and it is therefore, all too easy to dismiss these ideas due to the lack of scientific evidence. However, conceptually, minimally invasive endodontic-restorative philosophies appear to be valid, and therefore, in the pursuit of improved clinical outcomes, it is important that the efficacies of these treatment protocols are determined. Alongside an increased awareness of the preservation of tooth structure, developments in adhesive bonding, ceramic materials and the inevitable integration of digital dentistry, there is also a need to evaluate the efficacy of new treatment philosophies and techniques with well-designed prospective clinical studies.

Keywords: crown; dentine bonding; endocrowns; onlay; post; root filled teeth.

FIGURE 1

Pulp chamber preparation following completion of the endodontic treatment and prior to placement of composite resin core. The dentine surface has been cleaned with ultrasonics, after which alcohol has been used to sequester residual eugenol from the pulp chamber. Air‐abrasion in combination with aluminium oxide or bioactive glasses may also be used.

FIGURE 2

The placement of core materials in minimally invasive access cavities presents a challenge (a–d) preoperative periapical radiograph, intra‐operative images and post‐treatment radiograph of minimally invasive root canal treatment of 21. Predictable light transmission for use of conventional composite resin was not possible during core placement so a dual‐cure material was used in this case (e, f) ‘restoratively‐driven’ access during root canal treatment of 16. The diligent use of magnification, an elongated delivery tube to place the composite resin (e.g., Accudose; Centrix) permitted placement of the restoration without void formation.

FIGURE 3

Dye‐assisted confocal microscopy of resin‐dentine interfaces created using different bonding and restorative procedures performed in class 1 cavities subsequent root canal treatment in vitro. (a) Single‐projection images of the resin‐dentine interface created by the application of a bulk‐fill composite (Filtek One Bulk‐Fill; 3M ESPE AG) following the use of a universal adhesive (Scotchbond Universal; 3M ESPE AG) in self‐etching (SE) mode. It is possible to see a clear gap between the dentine (d) and the adhesive/composite (Ad/C) most likely due to polymerization shrinkage, which has caused the debonding in adhesive mode (b). (c) Further images of resin‐dentine interface, following conventional composite (Filtek Supreme XTE; 3M ESPE AG) placement with the use of a universal adhesive in SE mode. Once, again it is possible to see a clear gap between the dentine (d) and the adhesive/composite (Ad/C) due to polymerization shrinkage. (d) Single‐projection images of resin‐dentine interface created by the application of a flowable ‘bioactive’ restorative composite (ACTIVA Restorative; Pulpdent) following the use of a universal adhesive in SE mode. In this case, gap formation between the dentine (d) and the adhesive/composite (Ad/C) is much less evident. This may be due to the mechanical and compositional characteristics of the material (i.e., resin‐modified glass ionomer cement containing modified calcium phosphates), which are proposed to create less stress on the bonding interface, particularly when left undisturbed for a couple of minutes prior to light‐curing.

FIGURE 4

Dye‐assisted confocal microscopy of resin‐dentine interfaces created using an experimental self‐etching adhesive applied on dentine previously air‐abraded with bioactive zinc‐doped bioglass powder after 3 months of storage in artificial saliva. (a): Single‐projection images of resin‐dentine interface that was immersed in 0.5 wt% calcium‐chelating dye solution 26 (Xylenol Orange; Sigma–Aldrich) after maintaining the specimens for 3 months in artificial saliva (AS). It is possible to observe, especially at higher magnification (b), the presence of a clear calcium‐based mineral deposition within the resin‐dentine interface and inside the dentine tubules induced by the bioactive glass.

FIGURE 5

Lithium disilicate ceramic onlay (IPS e.max, Ivoclar Vivadent) placement following root canal retreatment of 36 (a, b) preoperative occlusal view and long‐cone periapical radiograph (c) cleaned and prepared dentine surface prior to deep margin elevation and core placement (d) completed core and onlay preparation (e, f) post‐treatment occlusal view and postoperative periapical radiograph.

FIGURE 6

Zirconia crown (Lava; 3M ESPE AG) replacement 25 and crown placement 24 following root canal retreatment (a, b) preoperative occlusal view and long‐cone periapical radiograph (c) completed root canal retreatment and dentine surface preparation (d, e) pre‐endodontic build up, fibre post and core placement (f) completed full‐coverage crown preparations (g) crowns prior to cementation (h, i) finished restorations with postoperative occlusal and buccal views (j) follow‐up periapical radiograph at 10 years.

FIGURE 7

Lithium disilicate onlay (IPS e.max CAD) placement following root canal treatment of symptomatic 38 (a, b) preoperative occlusal view and long‐cone periapical radiograph (c) completed root canal treatment and dentine surface preparation (d) completed core and onlay preparation (e–g) the onlay is fabricated using computer‐assisted design and manufacturing (CAD‐CAM) (h, i) finished restoration with postoperative occlusal view and follow‐up periapical radiograph (j).

FIGURE 8

Zirconia crown (Lava; 3M ESPE AG) replacement following root canal retreatment 21 (a–c) preoperative buccal views and long‐cone periapical radiograph (d–f) removal of cast post and root canal retreatment (h–j) internal bleaching followed by fibre post, composite core placement and thereafter, crown preparation (k) completed crown cementation (l) radiographic follow‐up at 3 years.

FIGURE 9

Lithium disilicate onlay (IPS e.max CAD) placement following root canal retreatment of 25 (a, b) preoperative occlusal view and long‐cone periapical radiograph (c) fibre post prior to cementation and core placement (d) completed core and onlay preparation with distal deep margin elevation (e, f) final CAD‐CAM restoration with postoperative occlusal view and follow‐up periapical radiograph.