Functional crown lengthening in a patient with severe tooth surface loss

Functional Crown Lengthening… In the first of a new series on the perio-restorative interface, Azim Malik and Ashley Sim examine the challenges of crown lengthening

Crown lengthening is a highly underutilised modality of treatment. It is seldom considered as part of a multidisciplinary treatment plan particularly since the advancement in adhesive dentistry.

However, crown lengthening in conjunction with fixed prostheses can offer superior aesthetics and functional solutions in patients with tooth surface loss.

A 28-year-old male with clear medical history presented to the clinic with severely worn dentition particularly in the anterior region (UR2-UL2 and LR2-LL2). His social history revealed a cariogenic diet in the past and trauma to anterior dentition 15 years prior to his presentation at our clinic.

Clinical examination revealed localised periodontal pocket of 7mm with bleeding on probing on the mesial aspect of the UL2, which was associated with a buccal swelling. A separate fibrotic lesion towards the gingival margin was also noted. This fibrotic growth (histologically proven fibroepithelial polyp) was previously excised twice and had recurred.

His occlusal vertical dimension was reduced. There was adequate width of keratinised tissue (Figure 1).

A periapical radiograph of the UL2 showed 50% horizontal bone loss on the mesial aspect of the UL2 with no obvious apical pathology (Figure 2). The UL2 was positive to vitality testing.

Functional crown lengthening Diagnosis and treatment plan

The following diagnoses were therefore made:

1. Localised periodontitis stage III Grade C unstable
2. Tooth surface loss in the upper anterior and lower anterior region
3. Lateral periodontal abscess associated with the UL2
4. Fibro-epithelial polyp around the UL2
5. Reduced occlusal vertical dimension

After a detailed discussion with the patient the following treatment plan was constructed.

1. Oral hygiene instructions, diet analysis and plaque and bleeding indices
2. Non-surgical periodontal treatment including root surface debridement of the UL2
3. Wax up of the upper and lower anterior dentition.
4. Upper labial frenectomy
5. Crown lengthening surgery in the UR3-UL3 incorporating the fibro-epithelial polyp on the UL2
6. Increasing occlusal vertical dimension using the Dahl concept
7. Definitive restorations including lower anterior composites and upper zirconia crowns
8. Provision of a Michigan splint to wear long term Diet analysis of the patient revealed a highly cariogenic diet, which was modified.

Treatment phase

Following non-surgical periodontal therapy the UL2 pocket depth reduced to 3mm with complete resolution of the lateral periodontal abscess. Once periodontal stability was achieved a surgical crown lengthening procedure was performed, which included resection of soft tissue and ostectomy (bone removal). The fibrotic growth was incorporated as part of the soft tissue resection. Sutures were removed two weeks post-surgery. Following initial soft tissue healing the upper and lower incisal edges were built up to increase the occlusal vertical dimension using the Dahl concept (Hemmings et al, 2000) in centric relation for nine months.

A customer incisal guidance table was used and the upper anterior teeth were subsequently prepared for zirconia crowns and restored at the new occlusal vertical dimension nine months after crown lengthening to ensure stability of the gingival margin (Wise, 1985).

The two-year follow up of the case can be seen in Figure 6.

Conclusion

Crown lengthening surgery in conjunction with fixed prostheses can offer a long-term aesthetic solution for anterior tooth wear. Definitive restorations should be provided at least six months after surgical crown lengthening to ensure stability of gingival margins.

References

Hemmings KW, Darbar UR, Vaughan S (2000). Tooth wear treated with direct composite restorations at an increased vertical dimension: results at 30 months. J Prosthet Dent 83: 287-293 Wise MD (1985). Stability of gingival crest after surgery and before anterior crown placement. J Prosthet Dent 53: 20-23

About the authors

Dr Azim Malik BDS (Birm) MFDS RCSEd, DipPCD RCSI, DClinDent (Lond), MPerio RCSEd is a specialist periodontist and implant surgeon at Norton Implants, where he takes referrals for periodontal diseases, implants and soft and hard tissue grafting. He has a particular interest in the management of peri-implant diseases, failing implants and treatment of soft tissue defects. Azim is the co-founder of Edudent Academy which delivers hands-on courses in crown lengthening and soft tissue grafting amongst others. Visit www.edudent.co.uk for more information.

Dr Ashley Sim BSc (Hons), BDS (London), PGCert, MFDS RCS (Ed), MSc, PG Cert in Imp Dent MClinDent (Endo) is a restorative dentist and implant surgeon.