INTRODUCTION
‘The complete dental solution is a holistic approach that recognizes as a significant factor the psychological well-being of the patient and provides a healthy appearance as well as functional restoration. Aesthetics is an inseparable part of today’s dental treatment.’ From a purely cosmetic standpoint, the value of the appearance of one’s teeth has taken on a greater importance in our society. The public places an increasing priority on a healthy and attractive smile. The dental profession’s traditional domain, centered around the eradication of disease, now finds itself on the threshold of uncharted territory: the enhancement of appearance. Yet, foundations of health, proper function, and sound scientific principles with consistency of results, reliability of treatment modalities and long-term prognosis also must prevail.
The essentials of an aesthetic smile involve the relationships between the teeth, the lip framework and the gingival scaffold.
THE LIPS
Garber and Salama stated that the lips form the frame of a smile and, as such, define the aesthetic zone. Liplines have classically been defined as being high, medium or low. In the typical low lipline, only a portion of the teeth is exposed below the inferior border of the upper lip. The high lipline shows a large expanse of gingiva extending from the inferior border of the upper lip to the free gingival margin. The medium lipline shows a nominal exposure of 1–3 mm of gingiva from the most apical extent of the free gingival margin to the inferior border of the upper lip. Thus, the teeth in their entirety are on display, as well as the interdental gingival tissue and the border of free gingiva around the cervical area of the tooth ( Fig. 15.1 ).
THE GINGIVAL CONTOUR
An irregular gingival arrangement, despite being healthy, may strike a discordant note, and it may become desirable to establish a certain harmony and continuity of form to the gingival margin. One significant feature of gingival morphology is the gingival line, which is defined as a line joining the tangents of the gingival zeniths of the central incisor and canine. The gingival zenith is the most apical aspect of the free gingival margin. It is commonly accepted that the gingival zenith of the two central incisors should be at the same level. The gingival zenith of the lateral incisors, however, should be slightly above (coronally) the central incisor’s zenith (<1 mm). The canines, in turn, would have the free gingival margin at the same level of the central incisors and matching one another ( Fig. 15.2, A ). Extending distally, the tissues on the premolars would be somewhat coronally positioned. However, a recent study observed, on analyzing maxillary casts of 103 young adults, that the gingival zenith is, in fact, apical to the gingival zenith of the incisors, and the gingival zenith of the lateral incisors is below (81.1%) or on (15%) the gingival line when the head is oriented in the axis orbital plane. Periodontic plastic procedures, such as the basic gingivectomy, soft tissue grafting or the apically positioned flap, may be used to change the silhouette form of teeth and their relative proportion.
THE TEETH
The dentist is concerned with the color, position and shape or silhouette form of teeth. The advent of adhesive dentistry has allowed a literally instantaneous change in the color, shape and position of teeth via bonding techniques such as porcelain-laminated veneers and direct composite bonding. It is possible to establish the appropriate height of the six maxillary anterior teeth, changing the aspect ratio of teeth for an improved aesthetic appearance. The tooth’s aspect ratio, or height-to-width contour, for the six maxillary anterior teeth is generally considered to be optimal when the tooth is 75% as wide as it is tall ( Fig. 15.2, B ).
GEOMETRIC PARAMETERS OF HARMONY
Elements of the aesthetically pleasing, well-balanced smile have been extensively reviewed. It is commonly accepted that the maxillary anterior teeth should be completely displayed during a full smile, with a maximum of 3 mm of gingiva revealed above the central incisors. According to Garber and Salama, within the confines of the lipline, the remaining two components of the smile, the gingival scaffold and teeth, need to be arranged in such a way as to develop a certain continuity of form, harmony and balance. Classically, the level of the gingival margins of the maxillary teeth parallels the form of the upper lip. The incisal edges of these maxillary teeth tend to follow the form of the lower lip. In a transverse dimension, the teeth should extend progressively posteriorly and laterally to fill the vestibule, extending to the corners of the smile ( Fig. 15.3 ).
Continuity of linear horizontal form between the gingival expanse, the teeth and the upper lip is critical. Any asymmetry in this parallelism disturbs the sense of balance in the composition, disturbing the flow, and results in an unaesthetic smile. By this definition, a high lipline in itself may not be unaesthetic if these basic rules are followed. However, in today’s mass media-influenced culture, many people consider even the slightest excessive display of gingival tissue, the ‘gummy smile,’ unattractive. The gummy smile or high lipline case with an expanse of soft tissue can result from two problems: (1) altered passive eruption and (2) vertical maxillary excess.
ALTERED PASSIVE ERUPTION
In a person with healthy dentition, each tooth and its alveolus actively emerges from its crypt. The teeth continue to erupt through the gingiva until they make occlusal contact with the teeth in the opposing arch. This stage is followed by passive eruption or the exposure of the teeth by apical migration of the gingiva. Altered or delayed passive eruption is the failure of the gingival tissue to adequately recede to the proper level to the tooth’s cementoenamel junction (CEJ). The consequence of this is short crowns and gingival excess. Coslet et al. classified altered passive eruption into two categories for differential diagnosis and appropriate treatment.
In type I, there is typically an excessive amount of gingiva, as measured from the free gingival margin to the mucogingival junction.
In type II, there is a normal dimension of gingiva when measured from the free gingival margin to the mucogingival junction. Although these might appear to be clinically similar in that there is tissue extended over the coronal portion of the tooth, therapeutically the diagnosis between the two types is essential to determine the appropriate treatment modality.
Type I can further be subdivided on an anatomical histological basis into subcategories A and B. This subclassification depends on the relationship of the osseous crest to the CEJ of the tooth.
In subcategory A, the dimension between the level of the CEJ and the osseous crest is greater than 1 mm, which is sufficient for the insertion of the connective tissue fibrous attachment component of the biological width.
In subcategory B, detected by the process of bone sounding via the sulcus, the osseous crest occurs in close proximity to the CEJ, thereby diminishing the space for the insertion of the connective tissue of the biological width.
The term ‘biological width’ refers to a length that includes:
- ⧫
the epithelial attachment, known as the junctional epithelium, which rests on the root’s cemental surface
- ⧫
the connective tissue fibers that insert on the root’s cemental surface and which are located below the junctional epithelium.
Based on necropsy studies conducted by Gargiulo et al., the average dimensions of the biological width were considered to be approximately 2.7 mm: about 1 mm for the junctional epithelium, 1 mm for the connective tissue attachment and 1 mm for the sulcus. In clinical practice, the authors have found this to be a more varied dimension, often exceeding the 3 mm average.
VERTICAL MAXILLARY EXCESS
According to Garber and Salama, the gummy smile frequently results from a skeletal dysplasia such as a hyperplastic growth of the maxillary skeletal base. This results in the teeth being positioned farther away from the skeletal maxillary base and a display of gingiva below the inferior border of the upper lip. Diagnosis in the high lipline case involving a vertical maxillary excess requires ruling out the case due to a superimposition of altered passive eruption in combination with maxillary hyperplasia. Garber and Salama proposed a classification for vertical maxillary excess. The classification was developed to help determine the most appropriate treatment modality. The diagnosis relative to the degree of severity is predicted on first treating the altered gingival display (removing the altered passive eruption component) to develop a normal tooth form (crown form). Degrees of severity I (2–4 mm of remaining gingival display), II (4–8 mm of remaining gingival display) and III (more than 8 mm of remaining gingival display) are then determined by the amount of gingival display. The treatment modalities range from orthodontic intrusion alone through complex treatments involving orthognathic surgery, orthodontics, restorative components and periodontal plastic procedures.
TREATMENTS FOR ALTERED PASSIVE ERUPTION AND VERTICAL MAXILLARY EXCESS: INDICATIONS AND CONTRAINDICATIONS
Treatment of Type I A Altered Passive Eruption
The typical case of altered passive eruption type I A exhibits short, square-looking teeth and an expanse of gingiva below the inferior border of the upper lip. A gingivectomy using scalpel, electrosurgery or carbon dioxide laser is indicated and will readily remove this tissue. This procedure will result in a revised silhouette form for the tooth that is more elliptical and attractive, and will resolve the unwarranted excessive display of gingiva apparent during smiling ( Table 15.1 ). When the amount of attached gingiva is normal or minimum (= 1.5–2.0 mm of attached gingiva), gingivectomy is contraindicated.
| Condition | Indications | Contraindications |
|---|---|---|
| Altered passive eruption type I A (>1.5–2.0 mm of attached gingiva) | Gingivectomy | Osseous resection |
| Altered passive eruption type I B (> 1.5–2.0 mm of attached gingiva) | Gingivectomy Apically positioned flap with osseous resection | – |
| Altered passive eruption type II A (≤ 1.5–2.0 mm of attached gingiva) | Apically positioned flap with osseous resection | Gingivectomy |
| Altered passive eruption type II B (≤ 1.5–2.0 mm of attached gingiva) | Apically positioned flap with osseous resection | Gingivectomy |
| Vertical maxillary excess – degree 1 | Orthodontics Orthodontics and periodontics Periodontics Periodontics and restorative dentistry Lip repositioning | Orthognathic surgery |
| Vertical maxillary excess – degree 2 | Periodontics and restorative dentistry Orthognathic surgery Lip repositioning | – |
| Vertical maxillary excess – degree 3 | Orthognathic surgery plus Periodontics and restorative dentistry where necessary | Lip repositioning |
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