Parekh Chandani1, Vandekar Meghna2, Vaid Nikhilesh3
1. Former Resident,YMT Dental College & Hospital,Navi Mumbai,India
2. Professor & Chair, YMT Dental College & Hospital,Navi Mumbai,India.
3. Visiting Professor, European University, DHCC, Dubai,UAE.
Excessive gingival display during smiling, or gummy smile, is an aesthetic problem for some patients. It may result from a variety of etiological factors ; therefore, proper diagnosis is critical before beginning the treatment.
In adults, when the gummy smile is caused by overgrowth of anterior vertical maxillary excess, the outcome may not always be successful by conventional orthodontic therapy alone. In such cases, surgical therapy, such as Le Fort impaction or maxillary gingivectomies, are often indicated to achieve a good smile. However, if patients are unwilling to undergo surgical treatment, an alternative method must be considered to treat the gummy smile.
Some investigators have shown successful intrusion of teeth with mini-implants as anchorage. Temporary anchorage devices (TADs) have changed the conventional conception of anchorage control and biomechanics in orthodontics. They have replaced many traditional types of mechanics and simplified orthodontic treatment. Lin et al. (1) demonstrated successful treatment of gummy smile patients using that skeletal anchorage.
The present clinical case describes the treatment of an adult patient with gummy smile using miniscrew anchorage
Diagnosis and etiology
An 18-year-old male patient presented with the chief complaint of gummy smile. The facial photographs showed excessive gingival display on smiling, slightly convex profile, and incompetent lip. When the patient smiled, he showed more than 4 mm of gingival exposure in the incisor region and more than 6 mm in the posterior region (Fig. 1).
The intraoral examination revealed Class I molar relationship on the left side and Class II relationship on the right side, mild mandibular arch crowding, 4-mm overjet, and moderately deep over bite, and the maxillary midline was deviated 3 mm to the right.
Fig. 1. Pre-treatment facial and intraoral photographs.
Cephalometric analysis showed a skeletal Class II relationship with an A point, nasion, B point angle (ANB) of 80 and an excess of dentoalveolar height on the molars and incisors. The McNamara analysis evidenced maxillary excess (A to nasion perpendicular [A- NPerp] 2 mm). Despite the dentoalveolar maxillary excess, the nasolabial angle was obtuse (nasolabial angle 940 ). The mandible presented excessive length (condylion to the anatomic point Gnathion [Co-Gn] 120 mm, maxillomandibular difference of 23 mm) and was protruded in relation to the cranial base (from the pogonion to the nasion perpendicular [Pog-NPerp] 6 mm). However, this was masked by the LAFH, which was also very increased (Lower Anterior Facial Height [LAFH] 70 ), thus contributing to the vertical pattern. The maxillary and mandibular incisors were buccally tipped and protruded (distance between the upper incisor tip and the nasion point A line [1-NA] = 7 , the angle between the upper incisor and nasion point A line [1:NA] 330 , distance between the lower incisor tip and the nasion point B line [1-NB] = 10 , the angle between the lower incisor and nasion point B line [1:NB] 350 , and Incisor Mandibular Plane Angle [IMPA] = 1050 ). The radiographic image is presented in Figure 2 and the cephalometric measurements in Table 1.
Fig. 2. Initial lateral cephalometric radiograph
| ARAMETERS | PRE TREATMENT |
|---|---|
| SNA | 82ø |
| N Pr. To A (mm) | -2 mm |
| Eff. Mx. Length (mm) | 89mm |
| SNB | 74ø |
| N Pr. To Pog (mm) | -16 mm |
| Eff. Mn Length (mm) | 112 mm |
| ANB | 8ø |
| Mx ? Mn diff (mm) | 23mm |
| Betaÿ angle | 24ø |
| Jarabak?s Ratio (%) | 68.90% |
| LAFH | 70 mm |
| U. Incisor to NA (deg/mm) | 33ø/7 mm |
| L. Incisor to NB (deg/mm ) | 35ø/10 mm |
| L. Incisor to mandibular plane | 105ø |
Table 1 : Cephalometric summary
ANB, A point, nasion, B point angle; A-NPerp, A to nasion perpendicular; Co, Condylion; LAFH, Lower Anterior Facial Height; FH, Frankfort horizontal plane; FMA, Frankfort mandibular plane angle; FMIA, Frankfort Mandibular Incisor Angle; Gn, gnathian; Go, gonial; IMPA, incisor to mandibular plane angle; LI, lower lip; LS, upper lip; NA, nasion point A; NB, nasion point B;; Pog, pogonion; SNA, sella nasion point A; SNB, sella nasion point B
Treatment objectives
The treatment objectives were
1) to reduce the gummy smile and protruded profile, and
2) to additionally distalize the maxillary right teeth, which was needed to correct the maxillary midline and obtain a good functional Class I molar and canine relationship.
Treatment alternatives
Two alternatives were presented to the patient to eliminate the gummy smile:
1) extract the left first premolar to achieve a canine Class I relationship and correct the dental midline, followed by maxillary impaction orthognathic surgery to eliminate the gummy smile and improve the profile; or
2) extract the maxillary first premolars and the mandibular second premolars, and use mini-implants as anchorage for retraction and intrusion.
After a review of the risks and benefits of the two options, the patient chose the more conservative method. The second alternative was elected because of some advantages of being less invasive and requiring a shorter treatment time.
Treatment progress
Maxillary first molars were banded with buccal tubes and lingual convertible tubes for a removable transpalatal arch. Transpalatal and lingual arches were placed to counteract buccal crown tipping toward the mini-implants. Mandibular first molars were banded and fixed; preadjusted edgewise appliances with 0.022 x 0.028-inch slot brackets were bonded in the remaining teeth.
Both arches were then aligned and leveled beginning with 0.012-inch nickel-titanium archwires up to 0.019 x 0.025-inch stainless steel archwires. At that time, the maxillary arch was changed for a 0.021 x 0.025-inch stainless steel wire and the transpalatal arch was adjusted in place ( Figure 3 and 4).
Fig. 3. Post Levelling and Aligning facial and intraoral photographs.
Fig. 4. Post Space Closure facial and intraoral photographs.
Then, two mini-implants were placed between the maxillary central and lateral incisors and two between the maxillary first molar and second premolars (1.8 mm in diameter and 6 mm in length (Fig. 5). An intrusive force of 100g in the anterior region and 150g (2) in the posterior region was applied by E- chain from the mini-implants to the maxillary archwire. Also, active modules were tied to the archwire straight were tied with a posterior vector of force to intrude and distalize the teeth.
Fig. 5. Mechanics For Maxillary Impaction And Distalization Using Microimplants.
The objective of the full slot maxillary archwire in conjunction with the transpalatal arch was to control the tendency of maxillary teeth to incline in the buccal direction due to the force of coil springs from the mini-implants. The transpalatal arch was contracted and reinserted in the palatal tubes to annul the buccal moment generated by the force of the coils. The transpalatal arch was also adjusted to allow posterior movement of the left teeth. After adequate intrusion to eliminate the gummy smile after 12 months, the right side Class II was nearly corrected and Class II elastics were necessary to conclude the anteroposterior correction on that side. Intermaxillary elastics were applied with 0.018-inch stainless steel wires in the brackets for better interdigitation of occlusion. The mini-implants remained stable during treatment and were removed under topical anesthesia.
After debonding and debanding, a removable Begg wrap around retainer was placed. The total active treatment time was 32 months (Figs. 6 and 7).
Fig. 6 Post Treatment facial and intraoral photographs
Fig. 7: Begg’s Wrap around retainer for both maxillary and mandibular arch
Treatment results
The gummy smile was nearly corrected, and in full smile view, the patient showed no more than 1 to 2 mm of gingiva. The post- treatment photographs and dental casts demonstrated Class I canine and molar relationships with normal over bite and overjet, and the dental midlines were coincident to each other and with the facial midline . The cephalometric analysis and superimposition showed intrusion and distalization of maxillary molars, which caused self-rotation of the mandible. The maxillary incisors were intruded and retracted. The maxillary anterior alveolar bone and gingiva were moved lingually and upward by tooth movement ( Fig 9). The post-treatment cephalogram (Fig. 8) evidenced acceptable parameters compatible with the extent of movement.
Fig. 8. Final lateral cephalometric radiograph
Fig. 9. Superimposition
Discussion
In this case, the mini-implants remained stable during the time of intrusive force application (12 months) (Fig. 5). The treatment time (32 months) was a little longer because of one-half Class II correction on the right side. The molar was distalized to correct the one-half Class II and intruded (Fig. 9). The mandible presented counter clockwise rotation during treatment, as observed on the tracing at treatment completion (red line). The protruded profile was straightened with this movement (Fig. 9). In an ideal situation, about 1 to 2 mm of gingiva will be apparent when the patient smiles (Fig. 6).
Excessive gingival display can be divided into several categories according to etiologic factors (3-4). The patient presented lip incompetence at treatment onset (Fig. 1). Many factors are involved in lip protrusion, and it is obvious that the amount of protrusion can be controlled by various orthodontic and surgical procedures. Retracting or protracting the incisors surgically or orthodontically can achieve concordant lip position. Superimpositions of pre-treatment and post-treatment cephalometric tracings showed significant improvement in teeth inclinations and angulations
When gummy smile is found in adults with long-face syndrome, caused by excessive vertical maxillary growth, orthognathic surgery is generally required to intrude the maxilla and eliminate the excessive gingival display. The increase in vertical facial height may be confirmed by cephalometric analysis. Specifically in this patient, the LAFH was 70 at treatment onset. Potential risks of jaw surgery include excessive hemorrhage, infection, loss of tooth vitality, and periodontal loss, as well as risks inherent to anesthesia. Because the risks and treatment costs could be high, our patient was reluctant to undergo surgery. He was willing to accept a compromised result.
This case report demonstrated that the use of miniscrew anchorage for maxillary intrusion is a viable alternative to orthognathic surgery for some patients who present with the chief complaint of gummy smile and who refuse surgery. Minimal patient cooperation (5) was required except for good oral hygiene. The mini-implants remained stable during all the active treatment time and were demonstrated to be an adequate anchorage option for the orthodontic treatment of an adult patient with gummy smile.
Conclusions
The maxillary molars were intruded and distalized to correct the maxillary midline and obtain a good functional Class I molar and canine relationship. The maxillary incisors were intruded and retracted, allowing the alveolar bone and gingiva to move lingually and upward by tooth movement.
The treatment objectives were achieved with reduction of the gummy smile and protruded profile. Individualized diagnosis and treatment planning are essential to appropriately address each patient’s needs and goals.
Each patient should be individually evaluated to determine if a nonsurgical approach may provide acceptable correction. The orthodontic treatment with skeletal anchorage cannot replace orthognathic surgery; however, considering the costs and risks of surgery, it may be used as an alternative for selected cases and if a patient refuses surgery, as demonstrated in this successful case of correction.
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- Panossian AJ, Block MS. Evaluation of the smile: facial and dental consider- ations. J Oral Maxillofac Surg 2010;68:547e54.
- Kaku M, Kojima S, Sumi H, et al. Gummy smile and facial profile correction using miniscrew anchorage. Angle Orthod 2012;82:170e7.
- Erverdi N, Keles A, Nanda R. The use of skeletal anchorage in open bite treatment: a cephalometric evaluation. Angle Orthod 2004;74: 381e90.
