Changes in nasal volume after surgically assisted bone-borne rapid maxillary expansion.

INTRODUCTION: The purposes of this study were to detect, locate, and examine the changes in transverse nasal width, area, and volume from bone-borne, surgically assisted rapid maxillary expansion (SARME) with the Dresden distractor by using computer tomography (CT). METHODS: Sixteen patients (average age, 28.7 years) underwent axial CT scanning before and 6 months after SARME. They also underwent CT fusion on specific bony structures. The nasal bone width was examined in the coronal plane. The cross-sectional images of the nasal cavity were taken of the area surrounding the apertura piriformis, the choanae, and in between. We calculated cross-sectional areas and nasal volume according to these data. RESULTS: All but 2 patients had an increase in nasal volume of at least 5.1% (SD, 4.6%). The largest value of 35.3% (SD, 45.8%) was measured anteriorly on the nasal floor, decreasing cranially and posteriorly. This correlated with the V-shaped opening of the sutura palatina. There was no significant correlation between increase in nasal volume and transversal expansion. CONCLUSIONS: Because most of the air we breathe passes over the lower nasal floor, SARME is likely to improve nasal breathing.

Skeletally-anchored rapid maxillary expansion using the Dresden Distractor.

INTRODUCTION: It was the aim of this study to carry out a 3-D analysis of the teeth, alveolar and skeletal structures during bone-borne, surgically-assisted rapid maxillary expansion (RME) with the Dresden Distractor (DD). We aimed to determine whether a translatory and skeletal movement of the segments would be possible while reducing the dento-alveolar side effects associated with tooth-borne RME. MATERIALS AND METHODS: Standardized axial computed tomography (CT) was performed on twelve patients averaging 25.3 years of age prior to and after RME with the DD. Reference planes and the triple-0-ELSA were defined bilaterally referring to the following anatomic points: the foramina spinosa, external auditory meati and the anterior margin of the foramen magnum. We measured the amount of movement that occurred before and after RME with the DD against ELSA. RESULTS: A screw activation of 6.0 mm led to a transverse expansion of 5.55 mm in the alveolar process in the premolar region, and of 4.87 mm in the molar region, with 8 degrees to 9.8 degrees of buccal tipping and an increase in width of 6.07 mm and 5.71 mm, respectively, occurred in conjunction with only slight buccal tipping of the premolars (3.1 degrees -4.6 degrees ) and molars (1,1 degrees -2.6 degrees ). These data signify, beyond the considerable skeletal efficacy, an uprighting of the teeth due to the multibracket appliance's torque effect, and a direct transfer of the expansion forces onto the bone. Autorotation of the mandible in forward and upward directions was possible due to the considerably less dental tipping resulting from RME with the DD in comparison to tooth-borne RME. This fact demonstrated that the DD is also well-suited for patients with vertical growth pattern. CONCLUSION: The bone-borne DD is an effective therapeutic method that spares the patient the negative side effects associated with tooth-borne RME such as root resorption, bone dehiscence, bite opening and excessive buccal tipping of the teeth. The prerequisites for stable occlusion are brought about by the fact that the expansion is skeletal in nature, with minimal dental tipping.