Bite alteration to reduce gummy smiles

This process requires a six- to eight-week healing process, which is not only painful¹, but esthetically displeasing during that period. Another method, which involves repositioning the lip after cutting into the vestibule, is equally invasive with an excessively long period of healing.²

Today, cosmetic dentists often perform a gingivectomy utilizing a scalpel, electrosurge or diode laser in order to correct an overly gummy smile. However, these methods are contingent upon the amount of biological width available in each individual patient.³ Two to three millimeters of gum tissue must remain over the bone after the tissue has been removed. This biological width limitation usually creates one of two options.

Either the patient must be subjected to invasive surgical gum flaps accompanied by bone removal or the patient must be satisfied with very little change in the gum-to-teeth ratio. If the patient presents with a significantly short vertical index (measured from the CEJ of tooth No. 8 or No. 9 to the CEJ of tooth No. 24 or No. 25), the gummy smile condition may not be satisfactorily corrected when only a gingivectomy is performed.

Cosmetic dentists train regularly to adjust horizontal smile abnormalities such as over-crowding and large gaps. The idea of changing the vertical dimension of occlusion as part of improving dentofacial esthetics is not new.⁴ While occlusal philosophies may differ, most will agree that the occlusion must be given careful consideration when changing its vertical dimension, both as part of the diagnostic process and to avoid possible iatrogenic results.

When the patient presents with a significant difference between the mandibular position at habitual occlusion relative to an optimized occlusal position, increasing vertical dimension can have dramatic cosmetic effects on a patient by increasing the crown-to-gum ratio and effectively decreasing the gummy smile.

The cases presented here illustrate that vertical abnormalities such as gummy smiles may sometimes be further enhanced and the need for surgical intervention minimized if the vertical dimension of the bite is altered.

In adjusting the vertical dimension, care must be taken to insure a functional occlusion in the finished case. Jankelson described the method for muscle relaxation to determine mandibular position at true physiologic rest.⁵ Application of transcutaneous electrical nerve stimulation (TENS) (J5 Myomonitor*) for a period of 30–40 minutes allows the muscles of mastication innervated by cranial nerves 5 and 7 to relax.

While there is no universal agreement among dentists on occlusal philosophy, the author has found the Jankelson method of establishing a true mandibular physiologic rest position (PRP) to be highly effective. PRP is objectively verified with surface electromyography and computerized jaw tracking (K7 Evaluation System).

The K7 System provides calculations that show when the patient is at physiological rest as compared to habitual rest. These calculations indicate how much vertical index can be increased or how much freeway space can be decreased without interrupting the patient’s true physiological rest position.

Concerns about changing the entire arch to effect anterior defects are unfounded for two reasons. First, the newly diagnosed mandibular position is verified as correct by using an orthotic before anything is done to the natural teeth. Secondly, this technique of treating a gummy smile is based upon opening the bite.

Therefore, when porcelain is added to the full arch to increase vertical dimension, it involves little to no destruction of the natural dentition because the restorations are placed over the occlusal surface.

In the author’s experience and as illustrated in these cases, once PRP of the mandible is established, the increased teeth-to-gum ratio is significant prior to the removal of any gum tissue. It is prudent to mention here that if the patient’s PRP does not differ significantly from habitual after TENS relaxation, very little change in vertical dimension would be available for this procedure.

Use of the Golden Proportion to establish a pleasing esthetic effect has been seen in art, architecture and various scientific fields for centuries and used in dentistry for at least 25 years.⁶

Like occlusal philosophy, some question its validity.^7,8 However, it is used by many today in plastic surgery, orthodontics and esthetic dentistry as an element of treatment planning of facial esthetics and, in the author’s experience, patients are highly pleased with the outcome.
Calculations utilizing the Golden Proportion equation can also be applied to tooth shape and will show whether the “golden” vertical index can be reached through a combination of bite correction and gingivectomy. These simple calculations indicate whether the vertical length of the patient’s smile will be more esthetically pleasing after the corrections have been made.

(Width of central incisor) ÷ 1.618 = golden length of central incisor

(Length of central incisor) x 1.618 = golden vertical index

Based on these two calculations, an orthotic in the optimal bite position for both esthetics and function can be fitted for the patient’s upper teeth.

The orthotic is worn for a period of approximately one month to be certain that no headaches, neck pain, grinding or chewing issues ensue. This period also provides the patient with time to become psychologically accustomed to the additional tooth length that shows prior to the gingivectomy and application of veneers. If the patient is dissatisfied with the length-to-width ratio of the teeth in the orthotic, adjustments can be made to the orthotic before beginning the procedure.

Correcting the bite before performing a gingivectomy can offer a greater esthetic result, significantly reducing the amount of gum tissue that shows before a gingivectomy is performed. It should be noted that placement of porcelain on the molar teeth to increase vertical height is extremely conservative because the porcelain is lying on top of the existing teeth.

Even if the available biological width is significant, correcting the bite allows the dentist to remove less gum tissue during the gingivectomy. A frenectomy can also be performed, when appropriate, to remove a small portion of the lip frenulum with a diode laser. This allows the lip to move down slightly over the previously exposed gums and can additionally reduce the amount of gum tissue that must be removed during the gingivectomy.

Case No. 1

A 27-year-old female presented with 13 mm vertical index (VI) requesting that her “gummy smile” be corrected or reduced. The average VI is 17–21 mm. Therefore, her VI would be esthetically pleasing if increased by a minimum of 4 mm, reducing the gum-to-teeth ratio.

 
The patient’s teeth were out of proportion, with the length to width ratio of the central incisors almost identical rather than the esthetically pleasing ratio of 75 to 80 percent width to length. Her gums were inflamed and in poor condition. Therefore, she was first referred to a hygienist for cleaning, root planing, deep scaling and debriding. (Fig. 1)

At physiological rest, the K7 Evaluation System showed that the patient’s VI increased to 17 mm before any gum tissue was removed. The tooth-to-gum ratio had already been increased significantly. The Golden Proportion equations were also utilized. The patient’s golden vertical index calculated at 16.7 mm, and the orthotic gave her a VI of 17 mm (Fig. 2).

It was determined that the patient would have an even greater esthetic result by further increasing the tooth-to-gum ratio. Sounding determined that 2 mm of gum tissue could be removed safely, an additional 2 mm was burned away utilizing a diode laser.

The diode laser immediately cauterizes the tissue and causes less bleeding and less postoperative stress for the patient than other gingivectomy methods.

In the image (Fig. 3), gum tissue has been removed from three teeth, showing the additional vertical length compared to the remaining teeth. The healing process following the diode laser gingivectomy is approximately two weeks.

Sounding indicated that a gingivectomy alone would have allowed for the removal of no more than 2 mm of gum tissue. In this case, the patient’s VI would have increased only to 15 mm, leaving her with a gummy smile even after the procedure was complete (Fig. 4).

After administering a local anesthetic, a frenectomy was performed on the patient to further release the upper lip and reduce the gum-to-tooth ratio (Fig. 5).

The bite was checked again and the temporaries were applied. The final VI increase for the patient following the bite correction, frenectomy and gingivectomy was 6 mm, increasing the VI from 13 to 19 mm. While the increase could have remained at 17, the additional 2 mm was an esthetic improvement (Fig. 6).

After the veneers were applied and the gums had healed, the patient showed an exceptional reduction in her gummy smile, as well as increased gum health with proper stippling (Figs. 7a & b).

Case No. 2

A 37-year-old female patient presented with a 12 mm vertical index and complaints of an overly gummy smile. Although her gums were healthy, she was referred to a hygienist for a thorough cleaning prior to her procedures.

The patient’s central incisors were 9 mm wide, while the Golden Proportion is 11.6 mm. The patient’s golden vertical index, therefore, was 18.8 mm, which was an increase of 6.8 mm from her current VI (Fig. 8).

Measurements of the patient’s teeth showed that the width-to-length ratio was almost identical (Fig. 9).

The Myomonitor and K7 Bite Evaluation System determined that the patient’s bite could be opened to a VI of 17 mm, which was a significant increase of 5 mm from her original VI. The patient wore an orthotic for a period of one month, after which her bite was rechecked and temporary teeth applied (Fig. 10).

Sounding determined that 2 mm of gum tissue could safely be removed. After a frenectomy and gingivectomy utilizing the diode laser, 2 mm of tissue was removed, further increasing the patient’s VI to 19 mm, allowing for an exceptional correction to the gummy smile condition of 7 mm from the original 12 mm VI (Figs. 11a & b).

 

* Myotronics, Seattle, WA, USA

Editorial note: A list of references is available from the publisher.

 

Contact info

Dr David S. Frey may be contacted at drfrey@drfreydds.com.