Smile Rehabilitation by Dr Heather Cowie

A comprehensive case study involving multiple indirect restorations in the conformative occlusal scheme

by Dr Heather Cowie

Introduction
This case demonstrates the use of tooth whitening and multiple indirect restorations using a combination of E.max veneers, a crown and a conventional cantilever bridge to rehabilitate a patient’s worn and discoloured dentition. The patient had previously received tooth whitening and bonding treatments that provided unsatisfactory short-term results, so she referred herself to the clinic and requested a long-lasting solution to rejuvenate and improve the aesthetics of her smile.

Case report
A 66-year-old patient attended the clinic as a new patient, seeking a ‘smile makeover’ to improve the appearance of her chipped, worn teeth.

Presenting complaint
The patient was primarily concerned about the discoloured and worn ‘see-through’ edges of her front teeth. She requested treatment to whiten her teeth and also wanted the ‘twisted’ UL2 to look straighter. However, the patient presented with problems from a crowned UR2 that was causing discomfort, and she mentioned that she also was unhappy with the colour of the crown, and wanted it replaced.

Medically, the patient was fit and well, with no medications or known allergies. A full history, clinical and radiographic examination were completed.

Extraoral
TMJs were normal with no dysfunction; no lymphadenopathy, facial swelling or tenderness was detected; lips were competent at rest.

Intraoral

• Incisal wear (NCTSL) affecting the upper incisor teeth.
• Mild rotation of UL2, LL4 and LL5.
• Localised anterior crowding (incisors).
• Generalised discolouration.
• Nonvital UR2 with failed crown and associated PA radiolucency.
• Bonded adhesive bridge (double-winged UL3 and UL6) with failing large amalgam restoration.
• Healthy soft tissues and periodontium.
• Medium gingival biotype.
• No active caries.
• Canine guidance.
• Posterior crossbite (LL4, LL5).

Smile analysis

• High lip line.
• Even gingival levels.
• Uneven incisal edges.
• Cant (which slopes up and posteriorly towards patient’s left).
• Inconsistent axial inclinations.
• Low embrasure point (UR1, UL1 open contact ‘black triangle’).
• Dental midline not coincident with facial midline (DM is left of FM).
• Wide smile (shows upper 5–5 when full smiling).

Treatment planning
UR2 was referred for root canal treatment, which was successfully undertaken by a colleague. Meanwhile, a diagnostic additive waxup of the proposed new smile was created and was shown to the patient. This enabled an indirect mockup to be done in the patient’s mouth and gave the patient a preview of her new smile, which she approved.

The following options were then presented and discussed with the patient:

1. Tooth whitening, upper and lower; replacement of crown UR2; bonding; and a new bridge or implant.
2. Tooth whitening, upper and lower; replacement of crown UR2; E.max veneers; and a new bridge or implant;.
3. Tooth whitening, upper and lower; orthodontics; replacement of crown UR2; E.max veneers; and a new bridge or implant.

The patient chose to have tooth whitening and E.max restorations because she wanted the best long-term aesthetic solution, which would be durable, long-lasting and easy to maintain. The patient opted for a new bridge instead of an implant to replace the existing metal-bonded bridge. A conventional bridge design with a full coverage retainer on the abutment (UL6) was decided upon, given that the amalgam which had to be replaced in UL6 was very large.

The treatment plan therefore consisted of in-office tooth whitening for both arches, followed by 2 weeks of ‘at-home’ whitening, and provision of seven E.max veneers, one crown, one conventional cantilever bridge and a protective acrylic nightguard.

The case took a total of 14 weeks to complete.

Treatment stages
Visit 1: Oral hygiene instruction and prophylaxis. A full-mouth scaling, debridement and prophylaxis was followed by in-office tooth whitening for 1 hour, using 6% hydrogen peroxide gel. Custom home-whitening trays were provided, along with instructions for wearing them overnight for 2 weeks, using 10% carbamide peroxide as per Haywood protocol.¹

Visit 2: Review. After 4 weeks, the patient returned for a whitening review; the diagnostic waxup verified and definitive restorative treatment plan finalised.

Visit 3: Preparations and prototype construction. Teeth were prepared according to the additive waxup, using the Galip Gurrel or ‘APR’ technique.^2,3 After local anaesthesia was administered, the crown on UR2 and the metal-bonded bridge were removed and new cores were placed in UR2 and UL6 using composite.

A preformed PVS stent made from the waxup was filled with Protemp bisacryl resin and placed onto the teeth. Teeth #11–13, #15, #21–23 and #26 were prepared through the waxup, to ensure the preparations are conservative and accurate for the planned final restorations. A facebow registration, PVS impression and shade analysis were undertaken. Prototypes were made using Telio shade BL3 (from the preformed PVS stent), and were spot-etched and bonded onto the teeth, polished and finished.

The occlusion was checked and the patient wore these for 6 weeks.

Visit 4: Shade verification and prototype review. The prototypes were reviewed to check for any functional or aesthetic changes and to confirm the shade choice. The patient requested a lighter shade—we agreed on BL2, and this was communicated to the laboratory.

A debond of the UR5 provisional was assessed and thought to have been caused by a minor occlusal interference, which was corrected. The provisional veneer was rebonded, and after reassessing the occlusion, an alginate impression was taken of the upper arch and sent to the lab for fabrication of the final E.max restorations.

Visit 5: Try-in and fit. The provisional restorations were removed and the E.max restorations were tried in using a neutral try-in paste. Shade, contacts, phonetics and occlusal checks were completed, and the patient was happy to proceed with cementation. 000 retraction cord, soaked in an aluminium chloride haemostatic solution, was placed to gently retract the gingiva.

The preparations were etched with 37% phosphoric acid, washed and dried thoroughly, then bonded using a fourth-generation bonding agent. The E.max fit surfaces were etched for 15 seconds with hydrofluoric acid, washed, rinsed and dried, and a coat of silane primer was painted and air-dried. The E.max restorations were bonded using dual-cured resin under split dam conditions, and light-cured into place. Adjacent teeth were isolated with PTFE tape; excess cement was removed, contacts were flossed and the occlusion was assessed. Cord was removed and oral hygiene instruction was given. The patient returned the next day for final refinements and received her acrylic night guard, which she was instructed to wear at to protect the porcelain from possible fracture.

Visit 6: Follow-up. At her review appointment, the patient said she was really pleased with the outcome, having felt that she had regained her confidence.

Discussion
This case demonstrates the importance of having a standardised protocol for smile design for patients who request smile make-overs. That protocol includes:

• An accurate diagnostic waxup.
• Presenting a mockup for the patient in his or her own mouth.
• Well-fitting prototypes during the provisionalisation phase (up to 6 weeks).

Rehabilitative smile design cases can be complex and costly for patients because they often involve more than one discipline in dentistry. These cases can sometimes take months to complete. It’s therefore necessary to clearly explain time frames and costs in detail, at the start of treatment and throughout the planning stages, so that patients can make an informed decision and give consent.

The importance of presenting an accurate diagnostic waxup for the patient is essential and this serves as a useful communication tool for patient and the clinician and technician alike.¹ The waxup allows accurate prototypes to be constructed and is helpful if any amendments to the design are required before construction of the final restorations.

Allowing the patient to wear well-fitting, comfortable and attractive prototypes that closely resemble the final restorations provided the patient with confidence and sufficient time to get used to the new appearance of their smile. Indeed, this method enables clinicians to make any necessary changes before the final restorations are fabricated. In this case, the patient decided to choose a lighter shade than what had been originally selected.

The other advantage of this method is that it reassures clinicians that there is good occlusal stability and if any debonds, fractures or aesthetic changes are required, these can easily be amended before providing the definitive restorations.⁴

Although this case was completed using a more traditional working approach; digital impressions and scanning techniques can also be used to improve patient comfort and reduce clinical and laboratory time.

References

1. Haywood, V.B., & Heymann, H.O., 1989. Nightguard vital bleaching. Quintessence Int, 20, 173-6.
2. Gurel, G., 2007. Porcelain laminate veneers: minimal tooth preparation by design. Dent Clin North Am, 51, 419-31, ix.
3. Magne, P. & Belser, U.C., 2004. Novel porcelain laminate preparation approach driven by a diagnostic mock-up. J Esthet Restor Dent, 16, 7-16; discussion 17-8.
4. Gurel, G., 2003. Predictable, precise, and repeatable tooth preparation for porcelain laminate veneers. Pract Proced