Case report
Treatment in a patient with congenital loss of both mandibular lateral incisors and severely retroclined maxillary central incisors

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Highlights

  • •

    Loss of 2 mandibular incisors was treated by extraction of maxillary premolars.

  • •

    Torque of retroclined maxillary incisors was corrected by a 2-stage mechanic system.

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    Good intercuspation was achieved by adjusting the torque of maxillary incisors.

  • •

    Accurate 3-dimensional diagnosis and effective mechanic management were performed.

  • •

    A light force was used to achieve bodily movement of incisors.

This case report describes the treatment of a patient with congenital loss of both mandibular lateral incisors and severely retroclined maxillary incisors. The treatment included bilateral extraction of the maxillary first premolars, accurate 3-digital setup, a 2-stage torque control strategy, and intricate mechanic management. The dilemma of tooth-size discrepancy was solved by ideal torque control to avoid interproximal enamel reduction. An ideal Class I molar and canine relation, as well as canine guidance in the lateral excursion movement, was achieved with good stability.

Section snippets

Diagnosis and etiology

A motivated woman, aged 21 years, came to the dental clinic with the chief complaint of irregular maxillary incisors. In the frontal view, she displayed a symmetrical facial appearance with no excessive exposure of maxillary teeth. She had a straight profile with upper and lower lips behind the esthetic line, a normal mandible, and deep mentolabial sulcus. In addition, the patient showed a normal nasolabial angle (Fig 1).

Intraoral photographs and dental casts showed an Angle Class I canine and

Treatment objectives

The treatment objectives were to maintain the facial profile and the posterior bite. In addition, a satisfactory Class I canine and molar relationship with normal overbite and overjet needed to be achieved by careful mechanic control.

Treatment alternatives

Three treatment approaches were provided to the patient with severe TSD.

  • 1.

    Nonextraction: Because both mandibular lateral incisors were missing, deep overjet up to 9 mm would ensue after maxillary alignment. Thus, excessive overjet would lead to compromised incisal guidance and pose a great challenge to stability and retention.

  • 2.

    Space opening and prosthesis placement: Because excessive overjet would lead to a high risk of relapse, space opening for 2 incisors might reduce overjet and provide

Treatment progress

Interactive self-ligating brackets (Empower; American Orthodontics, Sheboygan, Wis) by 2-2 active and 3-5 passive self-ligating with MBT prescription were bonded in the maxillary arch. No extraction was conducted at the initial stage to recover the torque of the central incisors. After 2 months of alignment with 0.012-in nickel-titanium round wire, the maxillary arch was straightened. A cephalogram was taken at this stage, showing the inclination of maxillary incisors was 100° with an overjet

Treatment results

This patient's facial profile was maintained, with the lips in a satisfactory status at rest. Angle Class I canine and molar relationship on both sides were achieved, and canine guidance was retained with the mandibular first premolars contacting the maxillary canines during the lateral excursion. The posterior segment was in good intercuspation, whereas the overbite and overjet became normal (Figs 6 and 7). The patient was satisfied with her dental and facial appearance.

The panoramic

Discussion

Extraction of 1 mandibular incisor had been reported in literature.9, 10, 11, 12, 13, 14, 15, 16 However, the treatment of congenital loss or extraction of 2 mandibular incisors has seldom been reported. Curiel et al12 reported 1 case with the congenital loss of 1 mandibular incisor, severe crowding, and proclination in the maxillary arch; the patient was treated with extraction of 2 maxillary premolars and 1 mandibular incisor, IPR in the anterior segment of the mandibular arch.

The retroclined

Conclusions

An adult patient with Class I malocclusion, congenital loss of the mandibular lateral incisors, and deeply retroclined maxillary central incisors was successfully treated by 2-stage orthodontic treatment: buccal tipping of crown of incisors in the first stage and bodily retraction of 4 incisors in the second stage. Through delicate control of the interplay between archwires and brackets, satisfactory torque control avoided any IPR in the mandibular arch in a patient with TSD. The good and

Acknowledgments

This work was supported by the Natural Science Foundation of Jiangsu Province (No. BK20171122), Nanjing Health Youth Talent Project (QRX17081), and NanjingClinical Research Center for Oral Diseases (2019060009).

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