Resective plastic periodontal surgery

Introduction

In 1988, Preston D. Miller proposed that the term « mucogingival surgery » should be replaced by « plastic periodontal surgery ». This change in terminology was intended to take in to account the aesthetic element and henceforth includes a wide range of techniques.

The aesthetics of the smile is determined not only by the shape, colour and the position of the lips and teeth but also by their relationship with the gingival tissues. Plastic periodontal surgery can change the appearance and shape of the gingivae (^{Borghetti and Monnet-Corti, 2000}).

Plastic surgery is normally an adjunctive procedure but there are also indications for resective plastic surgery. The latter enables treatment of excess tissue that risks prejudicing aesthetics, in order to re-establish the harmony and continuity of the gingival margin (^{Johnson, 1990}). Whether or not it is possible to remove excess tissue by the surgery will depend on the potential for clinical crown lengthening. It is necessary to undertake a preliminary assessment of the position and line of the smile, the gingival contour and their aesthetics (^{Borghetti and Monnet-Corti, 2000}).

In this article, we analyse the correction of asymmetry of cervical margins, the « gummy » smile and ridge deformities by resective plastic surgery, to the exclusion of other treatments aimed at crown lengthening for aesthetic reasons.

The line of cervical margins

Asymmetry of the margins

In the maxilla, the level of the gingiva determines the line of cervical margins. Whilst smiling, it is considered to be pleasing ; when it follows the lower border of the upper lip, when the margins of the central incisors are symmetrical (be they at the same level or 1 mm apical to those of the lateral incisors), when those of the canines are at the same level or more apical than those of the central incisors and when those of the lateral incisors are never more apical than those of the canines. The highest points of the incisor and canine margins must be aligned tangential to what is known as the « aesthetic gingival line » (^{Borghetti and Monnet-Corti, 2000}).

An excessive asymmetry of the gingivae in the anterior segment is a factor that frequently prejudices aesthetics, especially when it affects the central incisors. This may be because of incomplete passive eruption, trauma during childhood that has affected the normal eruption of the teeth, malposition of the teeth or the presence of a defective restoration.

A smile may be asymmetric without it being unpleasing because the symmetry of the gingival contour depends not only on the alignment of the teeth but also of the occlusal plane (^{fig. 1}).

Alignment of the margins

Treatment may involve one tooth or the whole segment. It may be combined with orthodontics and/or restorations. It should be recalled that realignment of the margins may involve root coverage or resective surgery (crown lengthening), depending on the aetiology (^{fig. 2a}, ^2b and ^2c .

The « gummy » smile

A smile is said to be « gummy » when more than 3 mm of gingiva are visible. It is caused by an excessive vertical growth of the maxilla or incomplete passive eruption, often associated with an increased tonus and short upper lip. It may be encountered in patients with gingival enlargement. A gummy smile is unsightly when there is a disproportion between the amount of visible gingiva and the height of the teeth.

Incomplete passive eruption

Incomplete passive eruption is also referred to as altered or retarded eruption. It would appear to be a developmental anomaly as it takes place after active eruption and is an interruption of its normal progress. Clinically, the teeth appear short and squat due to the fact that the gingiva covers part of their buccal surfaces. ^{Coslet et al. (1977)} distinguish two types according to the amount of keratinised gingiva : Class I with increased height of keratinised tissue and Class II with a normal height of keratinised tissue. Probing distinguishes subgroups IA and IB. In the first of these, the distance between the level of the cement-enamel junction and the alveolar crest is greater than 1 mm, which is adequate for the connective tissue attachment and the biological space (^{Viargues and Meyer, 1995}). In the second (IB), the distance between the level of the cement-enamel junction and the alveolar crest is less than 1 mm which limits the connective tissue attachment. There is an increase in the bucco-palatal width of the alveolar bone that causes an angulation of the bone crest towards the periodontal ligament. However, cementum is available for the anchorage of connective tissue fibres. Probing only records the most coronal part of the bone (^{Coslet et al., 1977} ; ^{Evian et al., 1993} ; ^{Dolt and Robbins, 1997} ; ^{Levine and McGuire, 1997} ; ^{Borghetti and Monnet-Corti, 2000} ; ^{Moshrefi, 2000} ; ^{Weinberg and Eskow, 2000} ; ^{Rechter and Corsair, 2002}).

Excessive growth in the anterior maxilla

Excess growth in the anterior part of the maxilla is caused by a skeletal dysplasia. ^{Garber and Salama (1966)} described a classification of this condition, related to its severity :

- Class I : 2-4 mm of gingiva visible ;

- Class II : 4-8 mm of gingiva visible ;

- Class III : more than 8 mm of gingiva visible.

Excessive anterior maxillary growth may also be associated with incomplete passive eruption.

Resective plastic surgery can be used to treat Class I cases but Class II and Class III cases require a multi-disciplinary approach, combining resective plastic surgery with orthognathic surgery, orthodontics and restorative dentistry.

Gingival enlargement

Gingival enlargement is characterised by an increased volume of gingiva. It may be secondary to plaque accumulation, mouth breathing, the presence of an orthodontic appliance but above all, to the use of certain medicaments ; immunosuppressive agents prescribed following organ transplantation (cyclosporin), antiepileptics (phenytoin) and calcium channel blockers (nifedipine) (^{Liébart and Borghetti, 2000}). Gingival enlargement mainly affects the upper anterior teeth, commencing with the interdental papillae. The gingiva encroaches on the buccal tooth surfaces forming false pockets. Aesthetics is compromised so that in the more severe cases, resective plastic surgery becomes necessary.

Compensatory eruption following severe tooth wear

Resective plastic surgery may also be used to treat a gummy smile caused by compensatory eruption following tooth wear (^{Bensimon, 1999}).

Treatment of the « gummy » smile

When necessary, resective plastic periodontal surgery may be combined with orthodontic and prosthetic treatments in order to create a pleasing gingival contour. It may involve an internal bevel gingivectomy or apical repositioning of the existing tissue. The latter is often combined with bone resection. The choice of surgical technique depends on the results of the clinical examination ; probing to determine the position of the cement-enamel junction, the amount of keratinised gingiva and the depth of the sulcus. Resective plastic surgery alters the shape and the proportions of the teeth and restores the clinical crowns to a pleasing height (^{Allen, 1993} ; ^{Townsend, 1993} ; ^{Levine and McGuire, 1997} ; ^{Robbins, 1999} ; ^{Robbins, 2000} ; ^{Jorgensen and Nowzari, 2001}) (^{fig. 3a}, ^3b, ^3c, ^3d, ^3e, ^3f and ^3g .

Gingivectomy

Gingivectomy is the treatment of choice when there is a large quantity of keratinised gingiva. In cases with a medium amount of keratinised gingiva, it may be combined with an apically repositioned flap. It allows treatment of Class I passive eruption and gingival enlargement. A line drawn on the gingiva acts as a guide to the scalloped incision. A number 15 blade is used to make the internal bevelled incision down to hard tissue. The excess soft tissue is removed with a curette. Gingivoplasty may be used to reduce the thickness of the tissue and to improve the gingival contour. The procedure is simple, quick and painless.

In the case of Class IB passive eruption or when a ledge of bone is evident after the excision of the soft tissues, a full thickness flap must be raised to permit bone resection (^{Wolffe et al., 1994}).

Apically repositioned flap

An apically repositioned flap is indicated when the keratinised tissue is of low or medium height. It is carried out in the normal way for crown lengthening (^{Brägger et al., 1992} ; ^{Taieb et al., 1999}).

The enlarged edentulous ridge

The edentulous ridge may sometimes be enlarged due to an excess of hard or soft tissue. Resective surgery allows recontouring in order to attain sufficient height for a pleasingly-shaped pontic.

Following removal of an old bridge, there may be an enlargement of soft inflammatory tissue associated with inadequate plaque control and/or compression by the pontic. The aetiological factors should be removed and then there should be a delay for the tissues to return to health under a provisional bridge. Any excess residual tissue can then be corrected by gingivectomy-gingivoplasty.

After removal of an over-erupted tooth or after good healing with new bone formation (without resorption of the adjacent bony septa), the alveolar ridge may be located at a level that is too coronal. After lifting a full thickness flap, the excess hard tissue is remodelled (^{Garber and Rosenberg, 1981}) (^{fig. 4a}, ^4b, ^4c, ^4d, ^4e, ^4f, ^4g, ^4h and ⁴ⁱ .

Conclusion

Periodontal plastic surgery is most often adjunctive but in the situations described, it may be resective. The resection of soft and/or hard tissues can improve the aesthetics in the anterior region. However, resective plastic periodontal surgery must be undertaken prudently ; it must respect the well-known rules of aesthetics and take into account the visibility of the area concerned.

BIBLIOGRAPHIE

• Allen EP. Surgical crown lengthening for fonction and esthetics. Dent Clin North Am 1993;37:163-179.
• Bensimon GC. Allongement coronaire chirurgical : protocole à vocation esthétique. Parodont Rest Dent 1999;19:333-341.
• Borghetti A, Monnet-Corti V. Chirurgie plastique parodontale. Paris : Editions CdP, 2000.
• Brägger U, Lauchenauer D, Lang NP. Surgical lengthening of the clinical crown. J Clin Periodontol 1992;19:58-63.
• Coslet JG, Vanarsdall R, Weisgold A. Diagnosis and classification of delayed passive eruption of the gingival junction in adult. Alpha Omega 1977;70:24-28.
• Dolt AH, Robbins JW. Altered passive eruption : an etiology of short clinical crowns. Quintessence Int 1997;28:363-372.
• Evian CI, Cutler SA, Rosenberg ES, Shah RK. Altered passive eruption : the undiagnosed entity. J Am Dent Assoc 1993;124:107-110.
• Garber DA, Rosenberg ES. The edentulous ridge in fixed prosthodontics. Compend Contin Educ Dent 1981;2:212-223.
• Garber DA, Salama MA. The aesthetic smile : diagnosis and treatment. Periodontol 2000 1996;11:18-28.
• Johnson RH. Lengthening clinical crowns. J Am Dent Assoc 1990;121:473-476.
• Jorgensen T, Nowzari H. Aesthetic crown lengthening. Periodontol 2000 2001;27:47-58.
• Levine RA, McGuire M. The diagnosis and treatment of the gummy smile. Compend Contin Educ Dent 1997;18:757-762;764;766.
• Liébart MF, Borghetti A. L'accroissement gingival secondaire à la prise de médicaments. J Parodontol Implantol Orale 2000;19:385-396.
• Miller PD. Regenerative and reconstructive periodontal plastic surgery. Mucogingival surgery. Dent Clin North Am 1988;32:287-306.
• Moshrefi A. Altered passive eruption. J West Soc Periodontol Periodontal Abstr 2000;48:5-8.
• Rechter MJ, Corsair MA. Correction of an aesthetic problem related to excessive display of gingiva. Dent Today 2002;21:50-53.
• Robbins JW. Differential diagnosis and treatment of excess gingival display. Pract Periodontics Aesthet Dent 1999;11:265-273.
• Robbins JW. Esthetic gingival recontouring-a plea for honesty. Quintessence Int 2000;31:553-556.
• Taieb T, Gallois F, Danan M. Les élongations coronaires chirurgicales préprothétiques. Cahiers Prothèse 1999;105:7-17.
• Townsend CL. Resective surgery : an esthetic application. Quintessence Int 1993;24:535-542.
• Viargues P, Meyer J. L'espace biologique minimal. J Parodontol Implantol Orale 1995;14:269-274.
• Weinberg MA, Eskow RN. An overview of delayed passive eruption. Compend Contin Educ Dent 2000;21:511-514;518;522.
• Wolffe GN, van der Weidjen FA, Spanauf AJ, de Quincey GNT. Lengthening clinical crowns - a solution for specific periodontal, restorative, and esthetic problems. Quintessence Int 1994;25:81-88.