Perio

Crown Lengthening Surgery

Periodontal surgery is not limited to the treatment of periodontitis but includes procedures that can be part of a wider restorative plan.

Broadly speaking, we can encounter two different scenarios requiring crown lengthening techniques.

  1. Functional: in cases of subgingival caries, coronal perforations, fractures, cervical root resorption or tooth wear.
  2. Aesthetic: excessive gingival display and/or discrepant gingival margins or altered passive eruption.
    A correct clinical assessment and a tailored approach based on the patient’s morphotype and site characteristics are all fundamental for a successful outcome.

Where aesthetics are the primary outcome, a diagnostic wax up should be agreed with the patient. This also allows the fabrication of a surgical template to use as a guide during the procedure.

Irrespective of the desired outcome (aesthetics or functional) crown lengthening is performed in line with the guiding principles of the ‘biologic width’. This requires a distance of 4 mm from the osseous crest to the proposed restoration margin or the new gingival margin.

Biologic width. In the new classification (2017), ‘biologic width’ has been renamed the Supracrestal Tissue Attachment & is defined as the ‘cumulative apical–coronal dimensions of the junctional epithelium and supracrestal connective tissue attachment’

Contraindications of crown lengthening surgery include

  • Teeth with existing poor crown-root ratios or expected following surgery
  • Where removal of bone risks exposure of the furcation (Herrero et al 1995, Lanning et al 2003, Pontoriero & Carnevale 2001)
  • Teeth with poor periodontal, endodontic or restorative prognoses

Even though the end goal is the same, there are different ways to lengthen the crown

  • In cases when there is a wide band of keratinised gingiva, additional crown height can be achieved by gingivectomy with or without osseous surgery.
    – External bevel gingivectomy is indicated where osseous resection is not required. To note: in cases of gingival pigmentation, external bevel gingivectomy will produce pink gingival tissue upon initial healing. It is important to consider the patient’s desire to maintain or lessen the existing pigmentation when working in the aesthetic zone. Any alteration will need to match the contralateral gingival pigmentation.
    – Internal bevel gingivectomy. This is the most common method of crown lengthening surgery and includes resection of the excess gingival tissue and osseous reduction. It can be indicated for single tooth crown lengthening where uneven gingival contours exists or for multiple teeth.
  • Where inadequate remaining keratinised gingivae exits, apical repositioning of the soft tissues is completed with or without ostectomy. and is indicated on multiple teeth of the same quadrant or sextant. It is contraindicated in single tooth procedures.

In specific cases of altered passive eruption, two factors have to be considered for the appropriate approach, (Coslet et al 1977):

Orthodontics. An alternative non-surgical/orthodontic approach is forced tooth eruption. This is used also to level and align teeth to achieve aesthetic harmony. Forced tooth eruption with fiberotomy is indicated when the aim is to maintain the gingival margin of the adjacent teeth intact. The action of cutting the insertion fibres every 7-10 days prevents the gingival margin from following the tooth being extruded (Pontoriero et al 1987). This technique is contraindicated in the presence of intrabody defects.

Instrumentation. Bone removal can achieved with conventional surgical burs – tungsten carbide or diamond coated burs; piezoelectric tips or specific lasers. Skilled soft tissue handling using a minimally invasive approach aims to reduce post-operative discomfort and reduce healing time. In aesthetic cases, management of the papilla is critical to prevent post-surgical loss and the development of ‘black holes’

When to restore? Soft tissue rebound has been investigated in detail. In 33% of the cases, coronal shift of 1-3 mm occurred, while in others (29%), 1-4 mm of recession was observed, over a period of six weeks to six months (Brägger et al 1992). Thick phenotypes showed a higher tendency of rebound, up to 12 months after surgery (Pontoriero & Carnevale 2001).

The decision therefore to wait 3 months or 6 months to restore will be determined by the nature of the case – functional or aesthetic – and the thickness of the remaining attached gingivae.

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About the authors

 

Dr Ros O’Leary
Ros has been on the GDC specialist list since its inception in 1999, limiting her clinical practice to periodontics for over 20 years. She is highly experienced in the treatment of gum disease and understands that patient involvement in the process of periodontal care is the key to success.

 

 

Dr Estela Baz
Having received her Periodontics MClinDent from Eastman Dental Institute, Estela now works at the Perio & Implant DRC, limiting her scope of practice to Implants & Periodontics.

 

 

References

Brägger, U., Lauchenauer, D. and Lang, N.P. (1992), Surgical lengthening of the clinical crown. Journal of Clinical Periodontology, 19: 58-63. https://doi.org/10.1111/j.1600-051X.1992.tb01150.x

Coslet JG, Vanarsdall R, Weisgold A. (1977) Diagnosis and classification of delayed passive eruption of the dentogingival junction in the adult. Alpha Omegan. ;70(3):24-8. PMID: 276255.

Herrero F, Scott JB, Maropis PS, Yukna RA. (1995) Clinical comparison of desired versus actual amount of surgical crown lengthening. J Periodontol. ;66(7):568-71. doi: 10.1902/jop.1995.66.7.568. PMID: 7562348.

Lanning SK, Waldrop TC, Gunsolley JC, Maynard JG. (2003) Surgical crown lengthening: evaluation of the biological width. J Periodontol. 74(4):468-74. doi: 10.1902/jop.2003.74.4.468. PMID: 12747451.

Pontoriero R, Carnevale G. (2001) Surgical crown lengthening: a 12-month clinical wound healing study. J Periodontol. 72(7):841-8. doi: 10.1902/jop.2001.72.7.841. PMID: 11495130.

Pontoriero, R & FJ, Celenza & Ricci, G & Carnevale, Gianfranco. (1987). Rapid extrusion with fiber resection: a combined orthodontic-periodontic treatment modality. The International journal of periodontics & restorative dentistry. 7. 30-43

Regeneration: New lease of life for periodontally affected teeth

Modern microsurgical instruments, novel flap designs, site specific suturing techniques and the use of magnification, have all contributed to the concept of periodontal regeneration.

Whilst resective procedures remain a viable tool in the periodontist’s armamentarium, a more conservative approach reduces morbidity and improves aesthetic outcomes. Guided Tissue Regeneration (GTR) aims to restore damaged or lost tissues to their previous form and function. In periodontitis, GTR refers to the formation of new cementum, a functionally orientated periodontal ligament, alveolar bone and gingival attachment.

New attachment can only be formed if cells of the periodontal ligament colonise the root surface during cementogenesis (Melcher 1976). If epithelial cells migrate into that area, new attachment cannot occur. In the same way, if cells from the lamina propria migrate into the area immediately coronal to the bone crest, no coronal regeneration of the alveolar bone can be expected.

The proof-of-principle study demonstrated that true regeneration could be achieved using a Millipore filter. The space provided by the filter allowed new periodontal ligament regrowth as epithelial cells were prevented from repopulating the wound, thereby creating the initial principles of guided tissue regeneration (Nyman et al. 1982).

Advances

In the last two decades, flap designs have changed dramatically following the development of new biomaterials and instruments. Minimally invasive surgery (Harrel 1999, Harrel & Rees 1995 and Trombelli et al. 2012), papilla preservation techniques such as the modified or simplified papilla preservation (Takei et al. 1989, Cortellini et al. 1995, Cortellini et al. 1999) and microsurgical approaches (Cortellini & Tonetti 2001 and 2005) have been introduced to improve the outcomes of GTR.

Local factors that influence bone infill

The size of the bony defect and the number of walls (1-3 walls/circumferential defects), plays an important role in the regenerative potential of the site, providing wound stability and maintaining space.

In cases of unfavourable architecture, for example wide defects (>37 degrees) or one wall defects, the additional use of allogenic graft materials or synthetic bone biomaterials has been suggested to prevent collapse the barrier and maintain the necessary space (Polimeni et al. 2005, Cortellini & Tonetti 1999). Tooth mobility can also influence outcomes and peri–operative management.

New Materials

A number of growth factors and bone morphogenic proteins have also been used in an attempt to enhance the innate regenerative potential. Platelet-derived growth factors have demonstrated regenerative potential of the periodontal ligament cells and osteoblast enhancing regeneration of the periodontal attachment in in-vitro studies (Ojima et al. 2003) and multicentre randomised control trials (Nevins et al. 2005).

Enamel matrix derivatives have been widely tested offering positive results at one year follow up in a systematic review showing mean attachment gain and probing depth reduction of 1.1 mm and 0.9 mm respectively (Esposito et al. 2009).

Suturing

Irrespective of the materials used, the stability of the fibrin clot adhering to the root surface at the initial phase of healing is critical to the outcome. During early healing, the structural integrity of the wound relies principally on suture closure.

Passive adaptation and approximation of the wound margins require mattress-suture techniques to evenly distribute tensile forces and deflect plaque accumulation away from the incision line, favouring primary intention healing. The suture material itself should allow adequate tensile strength during the critical period of healing of the initial 7 to 10 days (Burkhard & Lang 2015).

Conclusions

Regeneration is the ultimate goal for periodontal therapy. However, GTR remains a challenging procedure and is highly technique sensitive.

Prudent case selection, clinical assessment of the defect site (depth and configuration of the defect, width and volume of keratinised gingiva) , the potential for regeneration and selecting the most appropriate techniques and materials are essential. Precise surgical management of the wound (i.e. flap design and manipulation, space provision, wound stability and primary intention healing), has a direct impact on healing and level of success.

GTR is a well-documented and established procedure to induce regeneration in infrabony defects and Class II furcation defects (Tonetti et al. 2002). Such periodontal sites with persistent pocketing following initial therapy should therefore be considered for GTR. In selected cases, GTR can improve the prognoses of teeth significantly, enhancing longevity and stability for teeth previously regarded as having ‘poor’ prognoses.

About the authors

 

Estela Baz:GDC Number: 208972, Lic Odont. With Special interest in Periodontology. Having received her Periodontics MCinDent from Eastman Dental Institute, Estela now works at the Perio & Implant DRC, limiting her scope of practice to Implants & Periodontics.

 

 

 

Chong Lim:GDC Number: 70007, BDS (National U. of Singapore), MSc in Periodontics (Eastman Dental Inst., UCL), MSc (Distinction) in Dental Implantology (U. of Bristol). Chong heads the Perio & Implant DRC near Richmond Bridge. He is also involved with providing post graduate education for the ITI, Eastman Dental Institute & University of Bristol.

 

 

 

References

  • Burkhardt, R. and Lang, N. P. (2015) Influence of suturing on wound healing. Periodontol 2000 68: 270-281. doi:
  • Cortellini, P., Prato, G.P., Tonetti, M.S. (1995) The modified papilla preservation technique. A new surgical approach for interproximal regenerative procedures. J Periodontol 66: 261–266.
  • Cortellini, P., Prato, G.P., Tonetti, M.S. (1999) The simplified papilla preservation flap. A novel surgical approach for the management of soft tissues in regenerative procedures. Int J Periodontics Restorative Dent 19: 589–599.
  • Cortellini P, Tonetti M. Radiographic defect angle influences the outcome of GTR therapy in intrabony defects. J Dent Res 1999: 78: 381.
  • Cortellini, P., Tonetti, M.S. (2001) Microsurgical approach to periodontal regeneration. Initial evaluation in a case cohort. J Periodontol 72: 559–569.
  • Cortellini, P., Tonetti, M.S. (2005) Clinical performance of a regenerative strategy for intrabony defects: scientific evidence and clinical experience. J Periodontol 76: 341–350.
  • Esposito, M., Grusovin, M.G., Papanikolaou, N., Coulthard, P., Worthington, H.V. (2009) Enamel matrix derivative (Emdogain) for periodontal tissue regeneration in intrabony defects. A Cochrane systematic review. Eur. J Oral Implantol 2: 247–266.
  • Harrel, S.K. (1999) A minimally invasive surgical approach for periodontal regeneration: surgical technique and observations. J Periodontol 70: 1547–1557.
  • Harrel, S.K., Rees, T.D. (1995) Granulation tissue removal in routine and minimally invasive procedures. Compend Contin Educ Dent 16: 960, 962, 964 passim.
  • Melcher, A.H. (1976) On the repair potential of periodontal tissues. J Periodontol 47:256-60.
  • Nevins, M., Giannobile, W.V., McGuire, M.K., Kao, R.T., Mellonig, J.T., Hinrichs, J.E., McAllister, B.S., Murphy, K.S., McClain, P.K., Nevins, M.L., Paquette, D.W., Han, T.J., Reddy, M.S., Lavin, P.T., Genco, B.L., Lynch, S.E. (2005) Platelet-derived growth factor stimulates bone fill and rate of attachment level gain: results of a large multicentre randomized controlled trial. J Periodontol. 76:2205-2215
  • Nyman, S., Lindhe, J., Karring, T., Rylander, H. (1982) New attachment following surgical
  • treatment of human periodontal disease. J Clin Periodontol 9: 290–296.
  • Nyman, S., Karring, T., Lindhe, J., Planten, S. (1980) Healing following implantation of periodontitis affected roots into gingival connective tissue. J Clinical Periodontol 7 : 394-401.
  • Ojima, Y., Mizuno, M, Kuboki, Y, Komori, T. (2003) In vitro effect of platelet-derived growth factor-B-B on collagen synthesis and proliferation of human periodontal ligament cells. Oral Dis. 9:144-151.
  • Polimeni, G., Albandar, J.M., Wikesjo, U.M.E. (2005) Prognostic factors for alveolar regeneration: effect of space provision. J Clin Periodontol 32: 951–954.
  • Takei, H., Yamada, H., Hau, T. (1989) Maxillary anterior aesthetics. Preservation of the interdental papilla. Dent Clin North Am 33: 263–273.
  • Tonetti, M.S, Lang, N.P, Cortellini, P., Suvan, J.E., Adriaens, P., Dubravec, D., Fonzar, A., Fourmousis, I., Mayfield, L., Rossi, R., Silvestri, M., Tiedeman, C., Topoli, H., Vangsted, T., Wallkamm, B. (2002) Enamel matrix proteins in the regenerative therapy of deep intrabony defects. J Clin Periodontol. 29:317-325.
  • Trombelli, L., Simonelli, A., Schincaglia, G.P., Cucchi, A., Farina, R. (2012) Single-flap approach for surgical debridement of deep intraosseous defects: a randomized controlled trial. J Periodontol 83: 27–35.