Bonded versus banded rapid palatal expander followed by facial mask therapy: analysis on digital dental casts.

OBJECTIVES: To compare the dental effects produced by a bonded versus a banded expander combined with facial mask (FM) in patients with Class III malocclusion by means of digital dental casts. MATERIALS AND METHODS: Two groups of patients with Class III malocclusion and maxillary transverse deficiency in the deciduous or early mixed dentition were selected. The first group consisted of 25 subjects (12 females; 13 males) with a mean age of 7.4 years (SD 1.2 years) treated with a bonded expander and FM. The second group consisted of 25 subjects (13 females; 12 males) with a mean age of 8.1 years (SD 1.3 years) treated with a banded expander and FM. For each subject of the two groups, initial (pre-treatment, T1) and final (post-treatment, T2) dental casts were taken and scanned. Maxillary digital models of T1 and T2 were superimposed on the palatal rugae in order to analyse the maxillary anchorage loss. Significant between-group differences were tested with independent sample t-test (P < 0.05). RESULTS: No statistical differences were found for any of the variables observed. CONCLUSION: Orthopaedic treatment of Class III malocclusion with either a bonded or a banded expander and FM during the deciduous or early mixed dentition induced a significant expansion of the maxillary arch and a slight mesialization of the posterior anchoring teeth with no difference between the two intraoral appliance designs.

Palatal surface and volume in mouth-breathing subjects evaluated with three-dimensional analysis of digital dental casts-a controlled study.

OBJECTIVE: To compare the anatomical characteristics of the maxillary arch, identified as palatal surface area and volume, between mouth-breathing and nose-breathing subjects using a three-dimensional (3D) analysis of digital dental casts. METHODS: Twenty-one Caucasian subjects (14 females and 7 males) with a mean age of 8.5 years [standard deviation (SD) 1.6 years] were selected according to the following criteria: mouth-breathing pattern due to allergic rhinitis, early mixed dentition, skeletal Class I relationship, and pre-pubertal stage of cervical vertebral maturation. This study group (SG) was compared with a control group (CG) of 17 nose-breathing subjects (9 females and 8 males, mean age: 8.5 years; SD: 1.7 years). For each subject, initial dental casts were taken and the upper arch was scanned using a 3D laser scanner. On each digital model, 3D measurements were performed to analyse maxillary arch morphology. Between-group differences were tested with the independent sample Student's t-test (P < 0.05). RESULTS: In mouth-breathing subjects, changes in physiological function of the upper respiratory tract resulted in skeletal adaptations of the maxillary arch. In the SG, both palatal surface area and volume were significantly smaller when compared with values of the CG. In particular, the palatal surface area and palatal volume were, respectively, 13.5 and 27.1 per cent smaller in the SG when compared to the CG. CONCLUSIONS: Subjects with prolonged mouth breathing showed a significant reduction of the palatal surface area and volume leading to a different development of the palatal morphology when compared with subjects with normal breathing pattern.

Functional factors associated with continuous eruption of maxillary incisors in adulthood: A 10-year prospective cohort study.

PURPOSE: To investigate whether functional factors estimated by the masseter muscle thickness (MMT) and the maximum occlusal force (MOF), were associated with the amount of continuous eruption of maxillary incisors in adults. MATERIALS AND METHODS: Dental casts were taken twice in 24 adult female patients during a 10-year prospective cohort study. At the first appointment, ultrasonographic measures of the MMT and MOF were recorded. The casts were scanned into a digital model and measurements of the eruption and clinical crown lengthening (CL) of the maxillary incisors were calculated after superimpositions on the palatal region. Univariate and multivariate mixed effect regression models were used to assess the single and joint role of functional factors, with presence or absence of occlusal contacts and CL on incisor eruption. RESULTS: By using the linear mixed effects regression model, we observed that both the MMT and MOF were correlated with the maxillary incisor eruption. In particular, the thicker the masseter or the stronger the occlusal force, the lower the amount of eruption. Using a backward multivariable mixed effects model, the incisor eruption was correlated with the MMT combined with presence or absence of contacts and clinical CL. The amount of tooth eruption (0.32 mm on average) was positively associated with CL (0.29 mm on average); therefore, the greater the CL (gingival recession), the greater the amount of tooth eruption. The presence of occlusion contact between the maxillary incisors and their mandibular antagonists was found as an inhibitor of eruption in the multivariate model. CONCLUSIONS: The functional capacity of masticatory muscles, as estimated by the MMT, plays a role in the amount of maxillary incisor eruption. The stronger the masticatory muscles, the lower the amount of eruption.

Upper molar distalization on palatal miniscrews: an easy to manage palatal appliance.

Upper molar distalization supported by miniscrews has become increasingly popular in the last years. A detailed clinical and lab procedure for the realization of a distalization appliance (fast back or distal jet) connected to miniscrews inserted in the anterior region of the palate is presented. A case report illustrates the use of a fast back appliance supported by miniscrews to correct the mesial shift of the molars and of the premolars as a consequence of an early loss of the maxillary deciduous canines.