Harmonizing the White and Pink

Written by Gregori M. Kurtzman, DDS
Frequently, when treating the aesthetic concerns of the patient, practitioners focus on the teeth (the white) and ignore the gingiva (the pink). Yet, both these aspects need to be addressed to provide the best aesthetic outcome and to correct what is either naturally present or the result of wear and tear over the years. It is not unusual to restore the anterior maxillary teeth with direct resin veneers, porcelain veneers, or full-coverage crowns, and end up with a patient who may not be completely satisfied with the result. This is often on a subconscious level, and the patient and practitioner cannot pinpoint what doesn’t look “right.”

The best analogy to explain this: even the most beautiful picture needs a frame to do it justice. If we took the Mona Lisa and placed it in a cheap plastic frame from a local thrift store, would it look as beautiful as if it were framed in an expensive and elegant frame? When restoring the maxillary anterior teeth, we need to regard the gingival tissue as the frame for the teeth to be restored. Adjusting the gingival margins to make the central incisors appear even, to get the zeniths of the anterior teeth in harmony, and to correct any slant to the gingival planes should all be considered before proceeding with the restoration of the teeth. It is not uncommon for the gingival margins of the central incisors to have one more coronal than the other. Another common problem is the gingival margin of the lateral incisors being positioned more apical than the central incisors and canines. This can result during eruption of the teeth, either from passive eruption of the central incisors or a more apical eruption of the lateral incisors, or a combination of these processes.
In the healthy gingiva, with the absence of periodontal disease, the osseous structure follows the scalloped parabolic contour of the cemento-enamel junction (CEJ); from facial to interproximal at an average distance of 2.0 to 3.0 mm.1 Additionally, the interproximal bone height is on average 3.0 mm coronal to the facial crest of bone.2 As the soft-tissue topography is typically determined by the underlying hard tissue, the osseous “scallop” results in a gingival scallop of 3.0 mm.3 Examination of the periapical or vertical bite-wing radiographs will permit the clinician to determine the position of the alveolar bone relative to the CEJ of the teeth to determine whether the crestal bone is 2.0 to 3.0 mm apical to the CEJ, thus allowing for biologic width.1,2

Clinically, when the crestal bone is positioned coronal to the CEJ, a condition results in a phenomenon referred to as altered passive eruption.4 In this situation, the gingival margin will usually be located 3.0 mm coronal to the level of the crest of bone, and this more coronal positioning on the tooth creates the appearance of a short clinical crown.5 These visual findings are confirmed with clinical information obtained by “bone sounding.” Bone sounding involves using a periodontal probe to locate the CEJ, and determining whether it can be felt within the gingival sulcus or only when the probe penetrates through the base of the sulcus.6 The periodontal probe is also used to feel for the crest of bone. Normally, the crest of bone is located 2.0 to 3.0 mm apical to the CEJ.7 When considering the display of the gingival margin on the facial aspect of the teeth (in a healthy periodontium with no bone loss), the interproximal papilla will appear between teeth approximately 4.5 mm coronal to the interproximal crest of bone.8 Clinical display of excessive gingiva with short teeth, where the width of the tooth equals the length, requires a thorough diagnosis and consideration in the treatment plan to provide a predictable aesthetic outcome.9-11 Excessive display of gingiva can affect the overall aesthetics of the smile, becoming the focus instead of the frame of the smile. This can be the result of passive eruption of the gingival complex as the teeth erupt.12,13

Delayed or altered passive eruption exists when the gingival complex remains positioned coronal to the CEJ, with the attachment on the enamel instead of the cementum of the root, giving the appearance of short clinical crowns.14 Passive eruption is a common occurrence, and is often not recognized or treated. When the patient presents with passive eruption of the maxillary anterior teeth and facial development is complete, then the gingival levels will require correction before restorative treatment is initiated, or the final aesthetic result can be compromised.1,15 This will ensure that the gingival margins of the maxillary anterior teeth will be at their correct level, and aesthetics can be maximized following restoration.2 Probing of the facial sulcus will help determine where the crestal bone lies in relation to the gingival margin, and will identify those cases of true passive eruption; from cases where an osseous component needs to be corrected to gain more length in the apical direction.

Evaluating the Incisal Edge
The incisal edge position may also contribute to the length-to-width proportion issues due to incisal wear. Some patients may present with incisal wear in combination with passive eruption, resulting from continuing eruption as the teeth wear incisally and continue to erupt to maintain occlusal contact. This is evident whenever no wear is observed posteriorly and wear is observed anteriorly, and the anterior teeth are in contact when in maximum occlusion; this results in a flattening of the occlusal plane and an aged smile. The practitioner will need to decide if the anterior teeth need to be lengthened in an incisal direction in relation to the occlusal plane to provide optimal aesthetics with a more youthful smile.

Correcting the Aesthetics
Once the central incisor proportions are determined, the practitioner should focus on the height of contour of the gingival margin (zenith) on the central incisors.16 The proper placement of the gingival zenith on the central incisors is to have it positioned slightly distal to the middle of the long axis of the tooth. This also holds true for the canine and premolar teeth as well. This provides the central incisors, canines, and premolars with a subtle distal root inclination which is associated with a beautiful smile. On the other hand, the lateral incisor has its zenith at the midline of the long axis of the tooth. Additionally, the height of the gingival crest for the lateral incisor should be positioned ideally 1.0 mm more coronal than the gingival margins of the central incisor and canine.

The resulting healed and healthy gingival margins should have a “knife-edge” gingival margin.17 The gingival tissue can be corrected by a variety of methods, including: a scalpel, periodontal knifes (Orban/Kirkland [Hu-Friedy]), monopolar electrosurgery, bipolar electrosurgery, and lasers (diode and CO2). Hemorrhage control during surgery, when a correction of the gingival tissue is done with a scalpel or periodontal knives, is a challenge associated with these techniques; this can create aesthetic issues with immediate-placed direct or indirect restorations such as discoloration at the margins. Frequently, this necessitates performing surgery and allowing a short healing period before the restorations can be performed directly. Monopolar electrosurgery also has its negatives due to the high wattage used to cut the tissue with lateral heat generation resulting at the incision. Monopolar electrosurgery requires a dry field during treatment, and this may increase tissue inflammation during the initial healing period and subsequent tissue shrinkage. “Charring” of the tissue margins at surgery has also been reported with monopolar electrosurgery and may be a result of the need for operating in a dry field. This may cause the gingival margin to move apically as healing occurs, compromising the final aesthetics. Bipolar electrosurgery uses less wattage and has been used extensively in neurosurgery with no reported tissue shrinkage or marginal charring. Lasers are showing increased frequency of use and also have reported stable gingival margins with a lack of shrinkage upon healing.

With regard to the case to be discussed in this article, we will concentrate on the bipolar electrosurgery approach. Bipolar electrosurgery was developed to overcome the obstacles associated with monopolar electrosurgery. The technology used today in dentistry is a crossover from neurosurgery, where delicate incisions are required in wet fields with no lateral heat generation. The bipolar electrosurgery technology used in the course of treatment described below (Bident Bipolar Intraoral Surgical Unit [Synergetics]) transfers those neurosurgical requirements to the dental environment, allowing intraoral soft-tissue surgery in wet fields with char-free, nonbleeding incision margins. This permits placement of immediate composite resin restorations without contamination of the resin by hematologic byproducts, thus eliminating discoloration of the resin due to hemorrhage.