Effects of rapid maxillary expansion on the cranial and circummaxillary sutures

Abstract

Introduction: The aim of this study was to determine whether the orthopedic forces of rapid maxillary expansion cause significant quantitative changes in the cranial and the circummaxillary sutures.

Methods: Twenty patients (mean age, 12.3 ± 1.9 years) who required rapid maxillary expansion as a part of their comprehensive orthodontic treatment had preexpansion and postexpansion computed tomography scans. Ten cranial and circummaxillary sutures were located and measured on one of the axial, coronal, or sagittal sections of each patient's preexpansion and postexpansion computed tomography scans. Quantitative variables between the 2 measurements were compared by using the Wilcoxon signed rank test. A P value less than 0.05 was considered statistically significant.

Results: Rapid maxillary expansion produced significant width increases in the intermaxillary, internasal, maxillonasal, frontomaxillary, and frontonasal sutures, whereas the frontozygomatic, zygomaticomaxillary, zygomaticotemporal, and pterygomaxillary sutures showed nonsignificant changes. The greatest increase in width was recorded for the intermaxillary suture (1.7 ± 0.9 mm), followed by the internasal suture (0.6 ± 0.3 mm), and the maxillonasal suture (0.4 ± 0.2 mm). The midpalatal suture showed the greatest increase in width at the central incisor level (1.6 ± 0.8 mm) followed by the increases in width at the canine level (1.5 ± 0.8 mm) and the first molar level (1.2 ± 0.6 mm).

Conclusions: Forces elicited by rapid maxillary expansion affect primarily the anterior sutures (intermaxillary and maxillary frontal nasal interfaces) compared with the posterior (zygomatic interface) craniofacial structures.

Fig 1

Schematic representation of the sutures used in the study: A, frontal; B, lateral; C, axial views. 1, Frontonasal; 2, frontomaxillary; 3, frontozygomatic; 4, internasal; 5, nasomaxillary; 6, zygomaticomaxillary; 7, intermaxillary; 8, temporozygomatic; 9, pterygomaxillary; 10, midpalatal suture.

Fig 2

Coronal CT sections showing: A, the frontomaxillary suture before RME; B, the frontomaxillary suture after RME; C, the frontonasal suture before RME; D, the frontonasal suture after RME.

Fig 3

Coronal CT sections showing: A, the zygomaticomaxillary suture before RME; B, the zygomaticomaxillary suture after RME; C, the frontozygomatic suture before RME; D, the frontozygomatic suture after RME.

Fig 4

Coronal CT section rotated in a 45° clockwise direction showing: A, the internasal suture before RME; B, the internasal suture after RME; and coronal CT sections showing: C, the intermaxillary suture before RME; D, the intermaxillary suture after RME.

Fig 5

Sagittal CT sections showing: A, the pterygomaxillary suture before RME; B, the pterygomaxillary suture after RME; C, the nasomaxillary suture before RME; D, the nasomaxillary suture after RME.

Fig 6

Axial CT sections showing: A, the zygomaticotemporal suture before RME; B, the zygomaticotemporal suture after RME; C, the midpalatal suture before RME; D, the midpalatal suture after RME.

Fig 7

The rendering window of the software allows viewing of: A, 3-dimensional volume; B, sagittal, C, coronal, and D, axial sections. By adjusting the cursor over the point of interest, the corresponding images are updated.