The treatment of severe class II division 2 patients with deep overbites and gummy smiles using lingual appliances: a case series

A 30-year-old female patient presented with a request to have her palatally inclined upper incisors, deep bite, and gummy smile corrected using an aesthetic appliance. Her medical and dental histories were non-contributory.

From the frontal view, the patient exhibited a short lower facial third with a slight chin deviation to the right. The lateral view revealed a mildly convex profile with a normal nasolabial angle and a protrusive maxilla (Figure 1). During posed smiling, a gingival exposure of 3 mm was evident. No signs of a temporomandibular joint disorder were noted.

Figure 1.

On intraoral examination, the patient had full-cusp Class II canine and molar relationships on the right side and Class I canine and molar relationships on the left side. The transverse upper and lower arch widths were within the normal range. There was mild crowding of 1 mm in the lower arch and a 1 mm space between the upper central incisors. The lower curve of Spee was accentuated and the upper occlusal curve was reversed due to lingually inclined and extruded upper incisors. The upper dental midline was co-incident with the facial midline, but the lower dental midline deviated 2 mm to the right.

The lateral cephalometric analysis revealed a skeletal Class II relationship with a normally positioned mandible and a protruded maxilla (SNA: 85.7°, SNB: 79.6°, ANB: 6.1°). The vertical skeletal pattern was hypodivergent (FMA: 20.0°). The upper incisors were severely retroclined (U1/SN: 80.3°) while the lower incisors were slightly proclined (IMPA: 94.2°). The upper incisal display was large (5.8 mm). The upper and lower lips were normally placed (upper lip to E-line, -0.7 mm; lower lip to E-line, -1.2 mm) (Table I). The panoramic radiograph showed the presence of all teeth except the mandibular right third molar (Figure 2).

Figure 2.

The following treatment objectives were established: (1) to align the teeth and level the curve of Spee in both arches; (2) to correct the Class II molar and canine relationships on the right side to Class I; (3) to achieve a normal overjet and overbite; (4) to recover the upper incisors’ torque and preserve the lower incisors’ inclination; (5) to intrude the upper incisors and (6) to correct the lower dental midline deviation.

The ideal treatment option was orthodontic decompensation of the upper incisors followed by orthognathic surgery to correct the skeletal Class II relationship; however, the patient rejected surgical treatment. Hence, a non-extraction treatment option was selected considering the patient’s hypodivergent facial pattern and her lip positions in relation to the E-line. The Class II relationship and increased overjet after torque recovery and arch levelling would be corrected by entire upper arch distalisation using mini-screw anchorage combined with Class II elastics.

Treatment was initiated by bonding all teeth with 0.018” × 0.025” double-slotted lingual brackets (ADB, Medico, Korea) except the lower second molars to reduce the patient’s discomfort. The initial alignment and levelling stage utilised 0.014”, 0.016”, and 0.016” × 0.022” nickel-titanium and 0.016” × 0.022” stainless steel arch wires. The torque of the upper incisors and the overjet were gradually increased using the stiffer arch wires. After six months of treatment, a 15° pre- torqued 0.016” × 0.022” stainless steel arch wire was inserted in the upper arch. Two mini-screws (diameter, 1.6 mm; length 10 mm; Medico, Korea) were inserted into the palatal alveolar bone between the upper first and second molars. Entire upper arch distalisation was performed by applying a retraction force of 250 g on each side from the mini-screws to crimpable hooks on the main arch wire via closed coil springs (Figure 3). Additionally, Class II elastics (3/16-inch, 3.5 oz) were applied on both sides.

Figure 3.

After four months of distalisation, the overjet was normalised while the dental Class II relationship, retroclined upper incisors, and deep overbite remained. A decision was made to further increase the upper incisor torque via a 20° pre-torqued 0.017” × 0.025” stainless steel arch wire. Additionally, two mini-screws (diameter, 1.4 mm; length 8 mm) were inserted into the labial alveolar bone between the upper central and lateral incisors to apply intrusion forces of 20 g per side to these teeth. The intrusion forces were maintained for 10 months followed by the removal of the mini-screws when a normal overbite was obtained.

After 21 months of treatment, a dental Class I relationship with a normal overbite and overjet was achieved (Figure 4). During the finishing stage, some labial brackets were bonded to improve tooth alignment (cross-over technique).² Interproximal stripping was performed on the upper and lower incisors to reduce the gingival black triangles. The total treatment time was 27 months. After lingual appliance removal, fixed retainers were placed in both arches along with Essix retainers for nighttime wear.

Figure 4.

Post-treatment records show satisfactory results with a well-aligned dentition and improved smile aesthetics (Figure 5). Solid Class I canine and molar relationships were obtained on both sides along with a normal overbite and overjet. The upper anterior torque was improved and the curve of Spee was levelled. The excessive gingival exposure when smiling was eliminated. The two-year post-retention records showed the stability of the treatment results without signs of relapse (Figure 6).

Figure 5.

Figure 6.

Radiographs were not taken at the time of bracket removal due to the patient’s pregnancy but were obtained on the two-year follow-up. A lateral cephalometric analysis showed an improvement in the skeletal Class II relationship (ANB: 4.7°) (Figure 7). The upper incisors’ proclination significantly increased (U1/SN: 92.4°), while the lower incisors’ proclination increased only slightly (IMPA: 92.1°) despite the levelled curve of Spee and Class II elastic application. The panoramic radiograph confirmed adequate root parallelism without signs of root resorption. Cephalometric superimpositions showed the palatal root torque and intrusion of the upper incisors, the intrusion of the lower incisors, the distalisation of the upper molars, and the mesialisation of the lower molars (Figure 8).

Figure 7.

Figure 8.

A 25-year-old female patient presented with the chief complaints of a deep bite, retroclined upper central incisors, and an excessive gingival display when smiling. She strongly desired an invisible treatment appliance.

From the frontal view, the patient exhibited well- balanced facial proportions and her mandible deviated to the left (Figure 9). The lateral view showed a convex profile with a normal nasolabial angle and protruded maxilla. The posed smile revealed an excessive gingival exposure of 2 mm. No signs of a temporomandibular disorder were detected.

Figure 9.

On intraoral examination, the patient presented full-cusp Class II molar and canine relationships on the left side and end-on Class II canine and Class I molar relationships on the right side. The transverse dimensions of both the upper and lower arches fell within the normal range. There was moderate crowding of 4.5 mm and 4.0 mm in the upper and lower arch, respectively. The lower curve of Spee was accentuated and the upper occlusal curve was reversed with retroclined and extruded upper central incisors and labially displaced upper lateral incisors. The upper and lower left second molars were in a scissor bite. The upper dental midline was centered with the facial midline, but the lower dental midline deviated 1.5 mm to the left.

The cephalometric analysis showed a skeletal Class II relationship with a slightly retruded mandible and a protruded maxilla (SNA: 85.5°, SNB: 75.8°, ANB: 9.7°). The vertical skeletal pattern indicated a slight hypodivergence (FMA: 21.4°). The upper incisors were excessively retroclined (U1/SN: 73.9°) while the lower incisors were proclined (IMPA: 103.4°). The upper incisal display was slightly increased (3.7 mm). The upper lip was slightly protruded but the lower lip was normally placed (upper lip to E-line, 1.9 mm; lower lip to E-line, 0.2 mm) (Table II). The panoramic radiograph indicated the presence of all teeth, excluding the mandibular left third molar (Figure 10).

Figure 10.

The following treatment objectives were established: (1) to align the teeth and level the curve of Spee in both arches; (2) to correct the Class II molar and canine relationships on the left side and the Class II canine relationship on the right side to a Class I; (3) to obtain a normal overjet and overbite; (4) to regain the upper incisors’ torque and minimise the lower incisors’ proclination; (5) to intrude the upper central incisors; (6) to correct the scissor bite and (7) to centre the lower dental midline.

The optimal treatment approach involved first levelling and torquing the upper incisors, followed by orthognathic surgery to address the skeletal Class II relationship. However, the patient declined surgical intervention. Consequently, a non-extraction treatment plan was chosen, taking into account the patient’s hypodivergent facial pattern and the relationship of her lip positions to the E-line. The correction of the Class II relationship and increased overjet would be achieved through complete distalisation of the upper arch, utilising mini-screw anchorage in conjunction with unilateral Class II elastics after torque recovery and arch levelling.

Treatment commenced by bonding all teeth with 0.018” × 0.025” double-slotted lingual brackets (ADB, Medico, Korea), excluding the upper second molars and lower molars to reduce the patient’s discomfort and avoid strong occlusal contact with the upper left second molar bracket. The arch wire sequences were similar to the first case; however, the bite opening and upper central incisor torque recovery were more favourable in this case as the lateral incisors were labially displaced. The entire upper arch distalisation was performed using a 15° pre-torqued 0.016” × 0.022” stainless steel arch wire, along with two mini- screws (diameter, 1.6 mm; length 10 mm) inserted in the palatal alveolar bone between the upper first and second molars. Crimpable hooks and power chains, applying approximately 250 g per side, were employed during the retraction process (Figure 11).

Figure 11.

After eight months of distalisation, the upper second molar brackets were bonded and a re-levelling phase was initiated using a 0.016” × 0.022” nickel-titanium arch wire. During this phase, light retraction forces of 50 g per side from the mini-screws were maintained to avoid relapse (Figure 12). Additionally, cross elastics were applied from the lower left second molar lingual bracket to the labial upper left second molar bracket to address the scissor bite, along with Class II elastics (3/16-inch, 3.5 oz) on the left side. The entire upper arch distalisation continued for two months after engaging another 15° pre-torqued 0.016” × 0.022” stainless steel arch wire.

Figure 12.

During the finishing stage, interproximal stripping was suggested to improve gingival black triangles and the lower incisors’ procliation but denied by the patient. The total treatment time was 29 months. After removing the lingual appliances, fixed retainers were bonded in both arches combined with Essix retainers for nighttime wear.

The post-treatment records showed a favourable outcome with solid Class I canine and molar relationships bilaterally along with a normal overbite and overjet (Figure 13). The curve of Spee was levelled in both arches and the upper central incisor torque was normalised. The left second molar scissor bite and excessive gingival exposure when smiling, were addressed.

Figure 13.

A cephalometric analysis showed that the skeletal Class II relationship was reduced (ANB: 8.0°) (Figure 14). The upper incisor torque significantly improved (U1/SN: 94.1°), while the lower incisors were proclined (IMPA: 106°). The panoramic radiograph confirmed acceptable root parallelism without root resorption. Cephalometric superimpositions showed the palatal root torque and intrusion of the upper incisors, the intrusion and proclination of the lower incisors, the distalisation of the upper molars, and the slight uprighting of the lower molars (Figure 15).

Figure 14.

Figure 15.

The one-year post-retention records showed that the treatment results were stable without signs of relapse (Figure 16).

Figure 16.