Contouring an abutment tooth to aid placement of a resin-bonded bridge

Resin-bonded bridges (RBBs) have been used for the restoration of edentulous regions since the 1970s,¹ with Howe and Denehy being the first to describe the use of a non-preparation adhesive bridge bonded to acid-etched enamel using composite.² RBBs are minimally invasive fixed prostheses that reduce the endodontic risk to abutment teeth compared to more traditional fixed–cantilever and fixed–fixed bridge designs. Placement of RBBs still enables the use of alternative restorative treatment options later on (ie an implant-supported prosthesis). Several factors affect the survival rates of RBBs.³ Survival rates at 5 and 10 years have been reported as 83.6% and 64.9%, respectively.³

The following clinical case demonstrates a useful technique for the provision of RBBs. A patient attended the practice complaining of an unretentive denture that had replaced his upper left central incisor (UL1) (Figure 1). The patient wanted to consider his treatment options for this space, preferably with a fixed prosthesis. The UL1 had been lost due to previous trauma, and his denture was an immediate replacement prosthesis.

A clinical examination was completed involving both extra-oral and intra-oral assessments. No issues were noted with the temporomandibular joint (TMJ). His dynamic occlusion involved bilateral canine guidance during lateral excursions, an absence of working/non-working side interferences, and posterior disclusion during anterior protrusive movements. The patient was manipulated into centric-relation using a Lucia jig, the first contact was reported around UL5 but no significant slide was noted between retruded contact and intercuspal positions. A Class II division 2 incisal relationship was recorded. A BPE of 212/121 was recorded. The UR1 tested positive to ethyl chloride, and no significant mobility was noted. A peri-apical radiograph indicated a healthy tooth. No further restorative treatment was needed and, therefore, treatment options for the UL1 were discussed as follows.

No treatment: accepting his current denture, which the patient did not accept as it was unretentive.

A new partial denture: which the patient was not keen on as it was removable.

Resin-bonded bridge: a cantilever bridge using UR1.

Fixed bridge: a cantilever bridge using UR1. The patient was not keen on this due to the invasiveness of preparing UR1 for a crown.

Implant-supported prosthesis: the patient was not keen on this because of the invasiveness of the procedure and the financial costs.

When discussing the UL1 RBB, it was noted that a potential black triangle was present between the UR1 UL1 (Figure 2) and that this could potentially lead to show through of the metal wing.

Therefore, the potential use of a composite resin restoration to recontour the mesial aspect of UR1 was discussed. The advantages of this approach were that it was additive in nature, minimally invasive and relatively inexpensive. The patient was happy to investigate this treatment protocol and a basic chairside diagnostic wax-up on the articulated study models was advised (Figure 3).

The patient was happy with this appearance and the definitive treatment plan consisted of a composite restoration UR1 and a metal ceramic RBB UR1 UL1. A defect was noted in the buccal plate and therefore, the need for pink porcelain apically on the pontic was also discussed and accepted.

All general periodontal cleaning was completed, alongside tailored oral hygiene instructions prior to completing the restorative treatment. The restoration of the UL1 space is documented in Figures 4–12. A palatal index was taken of the diagnostic wax-up (Figure 4), this was trimmed on the palatal aspect to aid placement. Rubber dam was placed and secured with floss ties and wedges (Figure 5). The UR1 was restored using etch, bond, Venus Pearl (Kulzer) composite using the putty index (Figure 6). The restoration was polished and contoured after rubber dam removal using discs and composite diamond polishing paste (Figure 7). A putty-wash impression was taken alongside an opposing arch alginate, facebow registration and a pre-contact centric relation registration record. The laboratory technician attended the practice for shade match and characterization of the UR1. The UL1 RBB was returned (Figure 8) and the thickness of the metal wing was checked to ensure it was at least 0.7 mm in thickness (Figure 9). The RBB was cemented under rubber dam using the Panavia F2.0 (Kuraray) protocol for Maryland bridges and the patient was shown how to clean around the RBB using SuperFloss (Oral-B) following fit (Figure 10). The occlusion was checked after fit, and was reported as slightly high; however, posterior contacts had re-established at a subsequent recall appointment. The patient was very happy with the aesthetics of the UL1 RBB (Figures 11, 12).

The above clinical case demonstrated the use of a direct, no-preparation resin composite restoration to recontour the mesial aspect of UR1 and, in doing so, reduce the size of the black triangle formed after restoring the UL1 space using a metal ceramic RBB.