Many procedures can be done with a soft tissue laser, but the vast majority that orthodontists might perform fall into two categories: access gingivectomies¹ and esthetic procedures. Access gingivectomies involve exposing more tooth tissue for earlier or more ideal bracket or band placement. Esthetic procedures involve removing redundant gingival tissues to optimize gingival esthetics and improve appearance of completed orthodontic treatment. To perform these procedures most safely and efficiently, with the least discomfort for the patient, it is important to know what not to do. Three primary considerations should be kept in mind in performing soft tissue laser procedures: biologic width or zone, pocket depth, and keratinized tissue. For gingival esthetic procedures, several additional diagnostic considerations are of importance as well.

The concept of biologic width, or biologic zone, is important in restorative dentistry. When analyzing a series of gingivectomies, Garguilo et al.⁹ found that regardless of the amount of tissue removed, tissue regrowth resulted in an average connective tissue attachment (CTA) of 1.07 mm, a junctional epithelium (JE) thickness of 0.97 mm, and a sulcus depth of 0.69 mm. These workers suggested that the distance from the height of the crestal bone to the gingival margin should be approximately 2.5 mm. Cohen¹⁰ coined the phrase “biologic width” to refer to the combined JE and CTA: 0.97 + 1.07 = 2.04 mm.¹¹ Kois¹² extended this definition, adding all three—0.97 + 1.07 + 0.69 = 2.73 mm, with the result rounded to 3.0 mm—and termed this dimension the “biologic zone.” Restorative dentists found that placing margins within the biologic zone resulted in chronic inflammation, and Kois has suggested that a biologic zone of 3.0 mm or more is necessary for a healthy dentogingival complex.¹² When a restoration is to be placed within the patient’s biologic zone, the preferred solution would be to “sound the bone,” probing through the pocket to the bone, and then exposing and removing enough bone to restore the 2.5- to 3.0-mm biologic zone.

In general, orthodontists are neither equipped for nor interested in performing hard tissue procedures such as removal of bone. In nearly all cases, removing redundant gingival tissue and leaving a pocket depth of 1 mm will be all that is needed in a typical orthodontic procedure. Although an understanding of the importance of biologic zone is essential to aid in discussions with colleagues, a much more practical approach is to simply measure pocket depth and plan to leave a 1.0-mm pocket, with the recognition that in most cases, violating the biologic zone will result in relapse to a 1.0-mm pocket. If a proposed gingival procedure will leave a pocket of less than 1.0 mm, laser gingivectomy may not be recommended, and referral for osseous crown lengthening is the preferred method of management (Figure 12-1).

Keratinized tissue is the immovable, fibrous, coral pink tissue surrounding the neck of each tooth. It extends from the free gingival margin to the mucogingival junction. Keratinized tissue is resistant to recession from toothbrushing or eating. Unattached gingiva is the movable, darker pink tissue also known as alveolar mucosa and is not strong enough to resist recession from normal trauma. In planning a gingival procedure, care must be taken to maintain at least 2 mm of attached gingiva. If the planned gingivectomy violates this minimum, a laser procedure may be inappropriate, and referral for surgical creation of an apically positioned flap may be more appropriate. Although special dyes can be used to demarcate the mucogingival junction, it can easily be observed by having the patient move their lips and observing for corresponding movement of mucosa. In summary, the limiting factors to consider in planning most soft tissue procedures in an orthodontic office are to leave at least 1.0 mm of pocket depth and to preserve at least 2.0 mm of keratinized tissue.

When a tooth is slow to emerge or a bracket is difficult to position, removing excess tissue not only enhances esthetics but also speeds treatment and reduces required appointments. Figure 12-2 shows a partially erupted maxillary cuspid. In such a case, the following options can be considered:

When the tooth is visible just below the gingival surface but could take many months to emerge into the mouth (Figure 12-3A), the patient is often reluctant to visit the periodontist or primary care dentist for an exposure procedure, so orthodontic treatment is “on hold.” If sufficient keratinized tissue is present, laser exposure with immediate bracket placement is possible, thereby saving the patient’s months of waiting. In addition, the laser provides a clean, bloodless field, allowing a bracket to be bonded immediately after exposure (see Figure 12-3B, C). In the patient whose case is shown in Figure12-3, the tooth was rebonded 6 weeks later to improve bracket position and subsequently erupted to an ideal position. The initial window procedure was the only laser exposure performed. All additional tooth visibility was the result of eruption (see Figure 12-3D). The patient was thus spared months of treatment time and went on to attend school with an attractive smile and improved self-esteem.

A common approach to position brackets properly involves placing brackets in the center of the clinical crown. To do so accurately, the practitioner must be able to visualize the clinical crown, which can be difficult when gingiva obscures tooth anatomy. A simple gingivectomy exposes the entire clinical crown, allows more accurate bracket placement, and speeds completion of treatment. With this procedure, not only was the patient in Figure 12-4 spared months of treatment but the exposure also afforded better access for cleaning, thereby reducing the risk of gingival hypertrophy during continued orthodontic treatment.

Occasionally, a patient may have difficulty with oral hygiene, with consequent development of inflammatory gingival hyperplasia. With improved oral hygiene, the inflammation subsides, but the hypertrophy may not completely resolve. Figure 12-5 shows readiness for placement of full braces, but the gingival hypertrophy, partially erupted upper left cuspid, and unerupted upper right cuspid prevented ideal placement of brackets. A full-mouth gingivectomy was performed to remove excess tissue and expose the cuspids, allowing brackets to be placed properly and permitting the patient to maintain an improved level of hygiene during treatment.

In many patients, treatment cannot progress without banding or bonding second molars, but placement is hindered by an overlying operculum (Figure 12-6). Removing the excess tissue with immediate bonding allows treatment to progress. Operculectomy is one of the few procedures for which topical anesthesia may be insufficient, necessitating injection of local anesthetic.

Two important concepts of gingival architecture are gingival shape and gingival contour.² Gingival shape describes the gingival margin as seen in viewing a tooth “face on” (Figure 12-7). Several factors contribute to ideal gingival shape.^13–15 First, the gingival margins of the two central incisors should be at the same level and should form a smooth, sweeping curve; the apex of the curve should follow the contours of the cementoenamel junction (CEJ), with the height of contour inclined slightly to the distal. Second, the gingival margins of the canines should be at the same level as that of the central incisors. Third, the gingival margins of the lateral incisors should be 1.0 mm shorter than those of both the canines and the central incisors. Thus, when viewed from central incisor to cuspid, the gingival margin heights can be described as “high-low-high.”

Widths of central incisors average from 8.4 to 9.3 mm, and lengths from 10.4 to 13.0 mm.^11–15 The ideal ratio of width to length is in the range of 75% to 80%,^12,16–20 with greater than 80% resulting in too “square” a tooth and less than 75% resulting in too long an appearance.²¹ Using these ratios in concert with known dimensions of the tooth in question can help determine a more ideal treatment plan. These concepts are demonstrated in the clinical cases described in the following section.

Sometimes after completion of orthodontic treatment, the teeth are aligned, but gingival contours do not conform to acceptable norms. In patients with such esthetic issues, gingival recontouring can greatly enhance the smile.

In some situations, none of the anterior teeth exhibit ideal contours. Treatment planning involves evaluating the proportions of each tooth to determine ideal goals and designing the plan to ensure not only achievable goals but also sufficient time scheduled to complete the necessary procedures. First, measure the width of the central incisors. In Figure 12-11, for a patient who recently underwent debanding, the width of the central incisors is just over 9 mm (slightly wider than average). The estimated ideal width of a central usually is 80% of the length; so divide 9 by 0.8 for an estimated ideal length for the central of 11.25 mm. This becomes the initial goal for an ideal central incisor length.