The aim of the present study was to compare skeletal and dental changes after rapid maxillary expansion (RME) and slow maxillary expansion (SME) performed by a Leaf Expander (LE) with upper deciduous teeth as anchorage and using 3D CBCT (Cone Beam Computed Tomography) analysis. Mixed dentition patients were randomly divided in two groups, according to the different expansion used anchored on maxillary primary second molars: the RME group (n = 16) was treated with a Hyrax type expander, whereas the SME group (n = 16) was treated with an LE expander. CBCT scans were performed before (T1) and after treatment (T2) and analyzed with a custom landmarks system. A paired t-test was used for intragroup analysis between T1 and T2, and a Student t-test was used for intergroup analysis; statistical significance was set at 0.05. Both RME and SME groups showed a statistically significant increase in dental and skeletal diameters. Group comparisons between T1 and T2 showed a significant expansion rate in the RME group for upper permanent molars (p = 0.025) but not for deciduous molars (p = 0.790). Moreover, RME showed higher increases for skeletal expansion evaluated at nasal walls (p = 0.041), whereas at pterygoid plates did not show any significant differences compared with the SME group (p = 0.849). A significant transverse expansion could be achieved with the expander anchored on deciduous teeth. RME and SME produced effective both skeletal and dentoalveolar transverse expansion; RME produced more anterior expansion than SME but less control regarding the permanent molar decompensation. SME by LE therefore could be an efficient and helpful alternative in the treatment of transverse maxillary deficiency in growing patients.

The aim of the present retrospective study was evaluating skeletal, dental and soft tissue changes of two groups of Class II patients orthodontically treated with extractions of upper first premolars (U4 group) and upper first molars (U6 group). In total, 21 patient records (9M and 12F; mean age 12.5 ± 1.2 years) were selected for the U4 group, and 38 patient records (17M and 21F; mean age 13.2 ± 1.3 years) were recruited for the U6 group. Twenty cephalometric variables were analysed on standardised lateral cephalograms at baseline (T0) and at the end of orthodontic treatment (T1). Means and standard deviations (SDs) were calculated for both groups and increments were calculated. After revealing the normal distribution of data with the Shapiro–Wilk test, Student’s t-test was used to compare variables at T0 between groups. A paired t-test was used to analyse changes between time points within each group, and Student’s t-test to compare differences between groups at T1. Both groups showed a significant increase in the distance among upper second molars and the vertical pterygoid line (PTV-maxillary second molar centroid U6 group: 6.66 ± 5.00 mm; U4 group: 3.66 ± 2.20 mm). Moreover, the distance of upper incisors to the palatal plane significantly increased (PP-maxillary incisor tip U6 group: 1.09 ± 1.52 mm; U4 group: 0.20 ± 2.00 mm; p = 0.061). Significant changes were found for overjet (U6 group: −4.86 ± 1.62 mm; U4 group: −3.27 ± 1.90 mm; p = 0.001). The distance between upper lip and esthetic plane showed a significantly reduction in both groups (ULip-E Plane U6 group: −2.98 ± 1.65 mm; U4 group: −1.93 ± 1.57 mm). No statistically significant changes were found in sagittal or vertical skeletal values. The significantly larger reduction of upper lip protrusion and overjet in the U6 group compared to the U4 group suggests preferring molar extraction treatment for severe Class II with protrusive soft tissues’ profile and increased overjet. Since no differences on vertical values were found, an increased SN^GoGn angle should not be considered a discriminating factor for choosing molar extraction treatment.

The present study was carried out to evaluate the benefits from one-phase Class II Early Treatment (ET) using extraoral forces and functional appliances but without intermaxillary forces and eventual lower leeway space preservation compared to two-phase Class II Late Treatment (LT) with the need for extractions and full fixed appliances as well as lower incisor proclination. The ET group (n = 239, 115 M, 124 F, mean age 10.6 ± 1.2 years), with first premolars not in contact and the second deciduous lower molars preserved, was compared to the LT group (n = 288, 137 M, 151 F, mean age 12.4 ± 1.5 years). The ET group was first treated with headgears, growth guide appliances, or Teuscher activators and, in borderline crowding cases, with lower space maintenance by a lingual arch, lip bumper, or fixed utility arch. The LT group and the second phase of ET were treated with full fixed appliances including intermaxillary forces such as Class II elastics or noncompliance devices; headgear and a growth guide appliance were also used. Cephalograms and plaster models were taken before (T1) and after treatment (T2) to calculate cephalometric changes and space balance discrepancies. The differences between T1 and T2 were analyzed by a t-test for normally distributed data and by the Mann–Whitney Test for nonnormally distributed data at a level of p < 0.05. The groups were defined as statistically homogeneous at T1. A statistical analysis showed that the ET group (mean treatment time 35.3 ± 13.3 months) was significantly associated with a 22.2% lower extraction rate, 15.9% less need for a full fixed appliance, and more than 5° less incisor proclination in the nonextraction cases compared to the LT group (mean treatment time 25.9 ± 8.1 months); treatment time significantly increased in the ET group compared to the LT group. Early Class II treatment resulted in a significant treatment effort reduction in more than one third of the patients and less lower incisor proclination, even if it clinically increased treatment time.

The aim of this study was to compare the three-dimensional dentoskeletal effects of Haas-type and Hyrax-type expanders using primary teeth as anchorage for rapid palatal expansion (RPE). Thirty-four subjects in mixed dentition were divided according to their expander’s type: Hyrax (n = 16; 6F, 10M; mean age 8 ± 3 years) or Haas (n = 18; 14F, 4M; mean age 8 ± 2 years). Each patient underwent CBCTs before (T0) and after RPE (T1). Dentoskeletal changes were collected. A paired sample t-test and independent t-test were used to compare each variable within the same group and between groups, respectively, with a 5% significance. The Hyrax group showed an increase in all dentoskeletal parameters; skeletal expansion was significantly increased anteriorly (1.76 mm) and posteriorly (1.93 mm). The greatest dental expansion was observed in the anchorage unit (6.47 mm), about twice as much as permanent molars (3.42 mm). The same statistical significance of Haas group measurements was observed; anteriorly skeletal expansion (2.97 mm) was greater than posteriorly (1.93 mm) and dental expansion was greater on anchored teeth (6.80 mm) than non-anchored teeth (4.57 mm). No statistical significance was observed between Hyrax and Hass groups. CBCT analysis showed that, in RPE, the dental expansion was greater than skeletal expansion. No significant or clinical changes were observed between Hyrax and Haas appliances anchored to primary teeth.

Background: Panoramic radiography creates distortion in teeth position and inclination especially in lateral areas of the arches due to acquisition and curved shape of dental arch. The aim of this study was to evaluate panoramic distortion compared to cone-beam computed tomography. Methods: Mesiodistal angulations were measured on panoramic radiography. Mesiodistal angulations and buccolingual inclinations of the teeth were determined on cone-beam computed tomography scans. The previous measurements were then compared through Pearson correlation coefficient. Results: The results showed higher correlation between mesiodistal 2D angulation and buccolingual 3D inclination, especially for first premolars, rather than between mesiodistal angulations measured in 2D and 3D. Conclusion: Especially for the lateral areas of the dental arches, root mesiodistal angulation measured on panoramic radiography is not reliable; in fact, it is greatly influenced by buccolingual inclination. Therefore, clinical evaluation is highly recommended with panoramic radiography to provide correct diagnosis and the most satisfactory results.

(1) Background: To investigate condylar position in subjects with functional posterior crossbite comparing findings before and after rapid maxillary expansion (RME) treatment through 3D analysis; (2) Methods: Thirty-two Caucasian patients (14 males, mean age 8 y 8 m ± 1 y 2 m; 18 females mean age 8 y 2 m ± 1 y 4 m) with functional posterior crossbite (FPXB) diagnosis underwent rapid palatal expansion with a Haas appliance banded on second deciduous upper molars. Patients’ underwent CBCT scans before rapid palatal expansion (T0) and after 12 months (T1). The images were processed through 3D slicer software; (3) Results: The condylar position changes between T1 and T0 among the crossbite and non-crossbite sides were not statistically significant, except for the transversal axis. At T1, the condyles moved forward (y axis) and laterally (x axis), they also moved downward (z axis) but not significantly; (4) Conclusions: Condilar position in growing patients with functional posterior crossbite did not change significantly after rapid maxillary expansion.