Uma entrevista com James A. McNamara Jr

Mandibular Behavior after Rapid Maxillary Expansion: A Clinical Study

Background:

Rapid Maxillary Expansion (RME) is a primary part of the contemporary orthodontic treatment plans. In addition to the maxilla, it is important to know its effect on the other dentofacial components. Some studies showed dentofacial changes after RME in the sagittal and vertical planes. The clinical importance of these changes is controversial.

Objective:

To investigate the mandibular changes after RME as the only treatment intervention in the sagittal and vertical planes.

Methods:

Twenty-eight growing patients aged 4-14 years were included in the current study. The bonded acrylic splint expander was used. Lateral cephalometric radiographs were taken at the beginning of the treatment (T1) and after a retention phase of six months (T2). The mandibular changes were assessed using vertical parameters (SN.MP, MMA, LAFH/TAFH, S.AR/AR.GO) and sagittal parameters (SNB, S.N.POG, N.A.POG). The changes between T1 and T2 were examined by paired samples T-test.

Results:

Two parameters showed a backward rotation in the vertical plane. The parameter S.AR/AR.GO showed a significant increase. The skeletal convexity increased with no clinical significance.

Conclusion:

There were statistically significant changes in the sagittal and vertical planes with no clinical importance. RME may affect the mandibular condyle position.

Complete Maxillary Crossbite Correction with a Rapid Palatal Expansion in Mixed Dentition Followed by a Corrective Orthodontic Treatment

This case report presents the interceptive orthodontic treatment of a boy, aged 8 years 4 months with a Class I malocclusion with severe transverse maxillary deficiency and complete maxillary crossbite and correction using Haas expansion and fixed appliance. The treatment goals were to correct the posterior crossbite and anterior crossbite and restore the normality of the dentition and occlusion. In phase I, the patient was treated with a modified Haas-type palatal expander, which provided a clinically significant palatal expansion and increased the maxillary arch perimeter with favorable conditions for orthodontic treatment with fixed appliances in phase II. The optimization of E-space and the use of intermaxillary Class III elastics helped to maintain the mandibular incisors upright. A removable wraparound type appliance and a bonded lingual canine-to-canine retainer were used as retention. Although the literature has reported a high rate of relapse after palatal expansion, after 2 years 9 months of posttreatment follow-up, the occlusal result was stable and no skeletal reversals could be detected.