Objective: To determine if density measurements of several maxillary regions in Hounsfield Units (HU) and outcomes of rapid maxillary expansion (RME) are correlated. Is correlation powerful enough to give us direct information about maxillary resistance to RME? Materials and Methods: Twenty-two computed tomographic (CT) scans (14 years) are used in this archive study. Two CT records were collected, one before RME (T 1 ) and one after 3 months of retention period (T 2 ). Maxillary measurements were made using dental and skeletal landmarks in first molar and first premolar slides to measure the effects of RME. Density of midpalatal suture (MPSD) and segments of maxillary bone is measured in HU at T 1 . Correlation analysis was conducted between density measurements and maxillary variables. Regression analysis was then performed for variables that showed positive correlation. Results: There was no correlation between density and skeletal measurements. Intermolar angle (ImA) in molar slice showed statistically significant correlation with density measurements. The ImA variable showed the highest correlation with MPSD in frontal section (r 5 0.669, P , .01). Conclusions: There is correlation of 32.1-43.3% between density measurements and ImA increase. Our density measurements explain a certain percentage of ImA increase, but density is not the only and definitive indicator of changes after RME. (Angle Orthod. 2015;85:109-116.)
This article describes a new method that enables vector control during alveolar distraction osteogenesis in the treatment of a cleft palate patient. The patient presented with unilateral complete cleft lip and palate, and the alveolar part of the defect was covered by a mobile buccal flap. The distraction was performed by sliding the surgically released tooth segment with the help of an intraoral distractor over 1.5-mm stainless steel archwires held by metal crowns. This vector-controlled method enabled new bone and attached gingiva formation in harmony with the proper alveolar shape.
The interaction between form and function in the craniofacial region is a well-accepted fact in orthodontics. The aim of the present study is to objectively evaluate if mandibular sagittal symphyseal distraction causes an increase in the retroglossal airway size and hyoid position in a retrospective clinical study. The pretreatment (T0) and 3 months post-distraction (T1) cone-beam computed tomography images of 12 patients (mean age 17.1 years) were retrieved. The retroglossal airway volume and hyoid-mandibular plane distance, hyoid-C3 distance, sella-nasion-B point angle angle, lower incisor to mandibular plane, and Mandibular plane angles were measured using 3D medical imaging software. The average amount of distraction at the superior border of the bony transport segment was 6.2 mm and 4.4 mm at the inferior border. The changes in retroglossal airway volume (2943.2 mm3), incisor to mandibular plane (6.5°), and mandibular plane (2.1°) were significant. The changes in hyoid-mandibular plane distance and hyoid-C3 distances were not significant. However, a downward repositioning in Hyoid position was observed along with the mandibular clockwise rotation. This study showed that symphyseal dentoalveolar distraction osteogenesis, as a complementary to orthodontic therapy, can affect the form and size of the pharynx. Therefore, the airway size should be one of the diagnostic and decisive factors for an ideal treatment planning.
Anchorage is the most important concept in biomechanics of orthodontics. The well-known quotation from Greek Philosopher, Archimedes "give me a place to stand and I will move the Earth" explains the importance of anchorage perfectly. Anchorage protocol has to be realistic and at the same time enough to
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