Article Publication about Cosmetic Dentistry

When To Increase Tooth Proportion Gingivally and When To Increase Tooth Proportion Incisally With Veneers


December 11, 2008

By Grecy R. Martinez, DDS

The lips, the teeth, and the gingiva are the three components of a smile. The lips frame the smile, and the design and volume of the lips have a great influence on the amount of gingiva and teeth exposed during rest, function, and smiling.

The incisal edge of the maxillary central incisors is the most important factor in the creation of a smile. It serves to determine the proper tooth proportion and gingival level. One of the most important factors in dental esthetics is the visibility of the teeth when the lips are at rest. Central incisors that are not visible when the lips are at rest give an older appearance to the dentition. In young people, when the mouth is slightly open, approximately 3.5 mm of the incisal portion of the maxillary teeth are visible.

We elongate the incisal edge to correct incisal wear, inadequate tooth display, or disproportion of the crown. The patient's age and gender as well as the length and curvature of the upper lip will determine the length of the incisal edge. Also, the length of the maxillary incisors is important in anterior guidance and phonetics. The length for maxillary central incisors ranges from 10.4 mm to 11.2 mm.

One condition that creates unpleasant esthetics is the "gummy" smile. It may occur through overgrowth of the maxilla, a high lip line, or altered passive eruption, causing the appearance of short clinical crowns and excessive gingival display.

Gummy smiles can be corrected by orthognathic surgery, orthodontics, or periodontal osseous surgery. The upper lip's relationship with maxillary anterior teeth display and with the gingiva should be evaluated before any restorative procedure.

The lip line is classified as high, medium, or low. A low lip line covers the gingiva and a portion of the anterior teeth. It is difficult to see the teeth when the lips are at rest. The treatment is lengthening the crown if the crown-root ratio and the occlusion permit it.

A medium lip line shows the teeth, gingival margin, and the papilla. A medium lip line produces the most attractive smile.

In a high lip line, more than 4 to 5 mm of the gingiva is exposed in a moderate smile.

I will now present two different cases. Both patients needed correction of tooth proportion and had spaces between teeth. The first patient presented a gummy smile, a microden in Tooth No. 10, and a large diastema (Figure 1a). The amount of tooth exposed at rest was about 3 mm (Figure 1b).

Figure 1a

Figure 1b

Because the patient showed an adequate amount of teeth in the incisal, the treatment of choice was to increase the tooth proportion gingivally. The treatment plan was to improve the tooth proportion by keeping the incisal edges, crown lengthening with the Waterlase to raise the gum tissue 2 mm (Figure 1c), and porcelain laminate veneers from Teeth Nos. 5 to 12 (Figure 1d). The patient also underwent one-hour bleaching in the lower teeth.

Figure 1c

Figure 1d

In Figure 1f, we can see before-and-after pictures.

Figure 1f &mdash before

Figure 1f &mdash after

The second patient presented with disproportionate teeth, an anterior open bite, multiple spaces between the teeth, and a high lip line (Figure 2a). When the lips were at rest, the amount of tooth exposed was less than 1 mm (Figure 2b).

Figure 2a

Figure 2b

Because the patient did not show teeth at rest and had an open bite, the treatment of choice was to improve tooth proportions by increasing the length at the incisal edges with porcelain laminate veneers from Teeth Nos. 4 to 13 (Figure 2c). This patient also had one-hour bleaching in the lower teeth.

Figure 2c

In Figure 2d, we can see before-and-after pictures.

Figure 2d — before

Figure 2d — after

NOTE: For the treatment to be successful, the most important thing is to understand the patients and provide them with smiles that match their hopes and personalities.


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