COMPARISON OF TWO DIZYGOTIC TWINS’ ORTHODONTIC ANOMALIES and TREATMENT RESULTS

There is a considerable evidence nowadays that genes play a dominant role in the aetiology of malocclusion. The aim of this case report was to compare the orthodontic anomalies of dizygotic twins and to evaluate their treatment results.

Method:

Our patients were 11-year-old dizygotic twins. One was male and the other one was female. The patients had straight profile and no asymmetry. Cephalometric analysis showed that maxilla and mandibula were in normal position with Class I skeletal and dental relationship. The inclination of upper and lower incisors were more protrusive in the male patient than in the female. Postero-anterior radiographs demonstreated the measurements were close to each other, but were more distinct in the male one.

In oral examination, both twins had midline diastema due to high-frenulum and the form of lateral incisors. Patients had formless left lateral incisors and it was spectacular that only the male’s right maxillary lateral incisors were congenitally missing. Therefore,  treatment plan was to open the lateral space in the female patient and to close the diastema in the male. After levelling phase, space opening was made on rectangular archwire in the female and diastema was closed with elastic chain in the male. Treatment time was 13 months in both patients.

Result:

At the end of the female treatment, enough space for the right maxillary incisor was obtained and Class I canin-molar relationship was provided; diastema was closed and canine-canine relationship was finished as Class II because of tooth-size discepancies in the male patient. Frenilectomy was applied in both twins to prevent recurrence.

Conclusion:

Although the dizygotic twins had similar skeletal structure, one of the twins had missing teeth while the other one had no missing teeth. Both twins were treated successfully and the female twin was prepared for prosthesis.