Decision-making process for esthetic treatment of gummy smile: A surgical perspective.

Gummy smile is a quite frequently found esthetic alteration characterized by excessive display of gingiva during smiling. Several causes have been implicated in the literature, but a dearth of clinical decision-making process has been found in the surgical treatment of excessive gingival display. An external bevel gingivectomy with osseous correction was performed in anterior maxillary region in accordance with the proposed decision-making process. The clinical observation at 1 month postoperatively revealed restoration of natural smile with 1-2 mm of facial gingival display. The outcome seems to suggest that this proposed decision-making process can provide valid treatment options for gummy smile cases. Copyright:

INTRODUCTION

Smile is considered to be unesthetic when excessive amount of gingiva is visible. According to a classification when exposure of facial gingiva is >3 mm, it is considered as gummy smile (type 2).[1] Its prevalence has been estimated to be 10% in 20–30-year-old subjects, and it is more common in women (14%) than in men (7%).[2] Multiple clinical situations where gummy smile can occur include gingival overgrowth, altered passive eruption (APE), altered active eruption (AAE), short or hyperactive upper lip, and vertical maxillary excess. The aim of this article is to propose a comprehensive decision-making process of various treatment modalities for excessive gingival display through a surgical case scenario.

CASE REPORT

A 22-year-old fe male patient with no significant medical history reported excessive gingival display [Figure 1]. The smile of the patient was classified as type 2 as there was >3 mm of facial gingival exposure.[1] The authors proposed few points for preoperative examination of excessive gingival display which are as below:

Figure 1

Preoperative view showing gummy smile

Age of the patient

Facial symmetry and face height

Height of upper lip at rest, lip mobility, and lip symmetry

Width/length ratio of maxillary anteriors

Position of mucogingival junction (MGJ)

Sulcus depth

Measurement of width of supracrestal tissue attachment (SCA) through transgingival probing

Measurement of width of keratinized gingiva (KG) between gingival margin and MGJ

Relationship between cementoenamel junction (CEJ) and alveolar crest through radiograph

Crown–root ratio.

Extraoral clinical examination revealed symmetric facial features. Facial height measurements revealed no evidence of vertical maxillary excess. The length of the upper lip was 21 mm as measured from subnasale to the most inferior portion of upper lip at rest (normal length: 22–24 mm in males and 20–22 mm in females).[3] Intraoral examination revealed gingival margin excess to CEJ. Transgingival probing was done mid-facially on each anterior tooth to measure the width of SCA and sulcus depth. The position of MGJ was found to be apical to both CEJ and alveolar crest. The clinical parameters of all the involved teeth are depicted in Table 1. After clinical examination and radiographic analysis, the case was diagnosed as APE type 1.[4] APE is characterized by the cessation of passive eruption process after Phase II. Usually, the value of SCA of Phase II is approximately 0.5 mm greater than that of SCA of Phase III.[5] In the treatment of APE, we have to achieve the value of sulcus depth and SCA of Phase III of passive eruption postoperatively. For better understanding, we shall be denoting the SCA of Phase II and III as SCA-II and SCA-III, respectively.

Table 1

Clinical parameters of all involved teeth

	Tooth number
	11	12	13	14	21	22	23	24
Sulcus depth (mm)	2	2	3	3	2	3	2	2
Total KG (mm)	12	12	9	8	10	12	7	8
Preoperative transgingival probing (mm)	4	5	4	5	4	5	4	4
SCA-II (mm)	2	3	1	2	2	2	2	2

KG – Keratinized Gingival; SCA – Supracrestal tissue attachment

Alginate impression of upper arch had been taken and mock-up was done on the prepared model in accordance with the available data of sulcus depth and transgingival probing depth of all teeth and radiographic analysis. The gingival margin on the mock-up model was placed according to the required amount of gingival tissue to be excised guided by golden proportion for each concerned tooth.[6] Next, a silicon surgical guide was prepared on the model [Figure 2].

Figure 2

Silicon guide on mock-up model

The authors proposed a decision-making chart for treatment planning of excessive gingival display [Chart 1]. According to the chart, the present case falls under the third clinical situation where gingival margin is excess to CEJ, MGJ is located apical to CEJ, and the width of KG is >3 mm. However, surgical crown lengthening that includes external bevel gingivectomy with selective osseous correction was planned. The entire treatment plan was explained to the patient. Presurgical oral prophylaxis was done, and written informed consent was taken from the patient before surgery.

Chart 1

Treatment planning, CEJ - Cementoenamel junction; MGJ - Mucogingival junction; KG - Keratinized gingiva; ARF - Apically repositioned flap

Following injection of local anesthetic (lignocaine hydrochloride with 2% epinephrine 1:200,000), silicon surgical guide was placed over the teeth and external bevel incision was given on the gingiva following the marginal contour of the surgical guide [Figures 3 and 4]. This was followed by crevicular incision. Then, interdental incision was given on each interdental region of involved teeth by keeping the blade perpendicular to the long axis of the tooth. The excess gingival tissues were removed with the help of a universal curette [Figure 5]. Transgingival probing was performed again on each tooth to measure the distance between peroperative gingival margin and alveolar crest. The residual sulcus depth of all teeth was 0 mm. As the values of peroperative transgingival probing of all teeth were less than width of SCA-III + preoperative sulcus depth, selective osseous resection was planned. Subsequently, a full-thickness envelop flap was raised and extended up to 3–5 mm beyond the alveolar crest [Figure 6]. Now, the difference between the width of SCA-III + preoperative sulcus depth and peroperative transgingival probing value was measured. For example, in tooth no. 22, the width of SCA-III, preoperative sulcus depth, and peroperative transgingival probing were 1.5 mm (SCA-II [2 mm] −0.5 mm = 1.5 mm), 3 mm, and 2 mm, respectively. Hence, 2.5 mm of osseous resection is required on #22. However, point of caution to be exercised here that the osseous resection must not jeopardize post-operative crown-root ratio. CEJ was taken as the reference for bone reduction. The flap was then secured with interrupted sling suture (4-0 black silk) [Figure 7].

Figure 3

Placement of external bevel incision following the margins of surgical guide

Figure 4

Peroperative view showing line of external bevel incision

Figure 5

Excision of excess gingival tissue

Figure 6

Elevation of full-thickness flap followed by selective osseous correction

Figure 7

Periodontal flap secured with 4-0 silk interrupted sling suture

The following postoperative instructions were advised:

The patient was advised to take antibiotics (amoxicillin 500 mg TDS) for 5 days postoperatively

Nonsteroidal anti-inflammatory drug (paracetamol 650 mg BDPC) for 5 days postoperatively

Use of a chlorhexidine gluconate 0.2% oral rinse was advised twice daily

Lukewarm or cold semi-fluid diet on the day of procedure, along with easy to chew soft food with no sharp edges for 2 weeks, was also advised.

One-week postoperative follow-up showed satisfactory primary healing without any significant postoperative complication. Four-week postoperative follow-up showed complete soft-tissue healing with desired esthetic outcome [Figure 8]. The amount of facial gingival display on natural smile was 1–2 mm.

Figure 8

Four-week postoperative view

DISCUSSION

Treatment modality of gummy smile depends on the underlying causes. According to the proposed decision-making process, clinical examination should start with the assessment of patient's age as passive eruption process continues till 18–20 years.[4] Then, facial symmetry and face height should be analyzed. Skeletal analysis through radiograph should be done next to rule out vertical maxillary excess which can be treated with orthodontic treatment or orthognathic surgery (LeFort 1 osteotomy)[7] or a combination of both. This should be followed by upper lip length at rest and at mobility. Short or hyperactive upper lip can be treated by lip-repositioning surgery with or without botulinum toxin therapy.[8] After ruling out short or hyperactive upper lip and vertical maxillary excess, intraoral clinical examination should be carried out focusing primarily on periodontal parameters. Width of KG, position of MGJ with respect to CEJ, sulcus depth, and relationship between CEJ and alveolar crest should be assessed.

Among the various causative factors of gummy smile, APE and AAE are comparatively tricky clinical situations that involve periodontal tissues. In type 1 APE, the MGJ is situated apical to both CEJ and alveolar crest, whereas in type 2, MGJ is situated at the level or coronal to CEJ.[4] The AAE is premature achievement of occlusal relationship with opposite teeth characterized by position of osseous crest close to CEJ.

The treatment of choice for APE is surgical crown lengthening which includes gingivectomy and/or apically repositioned flap (ARF) with selective osseous correction. The proposed decision-making process guides the clinician to select between gingivectomy and/or ARF through preoperative measurement of width of KG and position of MGJ in relation to CEJ. In case of type 1 APE, preoperative estimation of remaining KG after demarcation of amount of gingival tissue to be removed will guide the clinician to choose between gingivectomy and/or ARF. In an attempt to preserve at least 2 mm of KG postsurgically, a threshold level of 3 mm has been considered. In type 2 APE (where KG >3 mm), if KG of involved tooth is greater than KG of adjacent/contralateral/opposite normal tooth, then the amount of KG that is excess in involved tooth has to be excised through gingivectomy and it is followed by ARF. Whereas, only ARF is indicated when KG is ≤3 mm.

Apart from abovementioned clinical situations, gummy smile due to dentoalveolar abnormalities such as deep bite and retroclined incisors can be treated by orthodontic intrusion/orthognathic surgery.

Regarding osseous resection, several authors have various perceptions. The suggested distance between the bone crest and CEJ or gingival margin to re-establish biological width varies between 1 mm and 3 mm.[9] In the proposed decision-making process, the authors considered the preoperative value of sulcus depth and width of SCA of each individual tooth to evaluate the amount of bone to be removed in each tooth. Vacek et al. reported a wide range of dimension of the biologic width from 0.75 mm to 4.3 mm through a cadaver study.[10] Hence, it would be a wise approach to consider the specific width of SCA of each tooth for the amount of osseous resection required. Gargiulo et al. in 1961 demonstrated that the mean average value of connective tissue attachment and sulcus depth of all examined teeth remained constant in all phases of passive eruption process, but the mean average value of epithelial attachment decreased approximately by 0.5 mm from Phase II to Phase III of passive eruption process.[5] Hence, roughly we can say that the transgingival probing value in Phase III of passive eruption would be approximately 0.5 mm less than that of Phase II. In an attempt to simulate the clinical picture of dentogingival unit similar to Phase III of passive eruption, osseous resection should be done to maintain a distance equal to the width of SCA-III + preoperative sulcus depth, between gingival margin and alveolar crest. Osteoplasty is usually indicated in order to ensure a physiologic morphology of the alveolar bone. If, in any situation, the preoperative sulcus depth is >3 mm, then the value of sulcus depth should be considered as 3 mm only to avoid excessive osseous resection (for example, pseudopocket).

The result of the present surgical crown-lengthening procedure seems to suggest that this proposed decision-making process can be used for diagnosis and treatment planning for gummy smile cases with desired esthetic and biological needs. The proposed flowchart provides a comprehensive, clinical-oriented, and simplified algorithmic preoperative examination and treatment plan. It also stresses the fact that the value of preoperative transgingival probing and crown–root ratio strictly guides osseous correction.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.