BackgroundThe aim of this study was to evaluate the predictability of F22 aligners (Sweden & Martina, Due Carrare, Italy) in guiding teeth into the positions planned using digital orthodontic setup.MethodsSixteen adult patients (6 males and 10 females, mean age 28 years 7 months) were selected, and a total of 345 teeth were analysed. Pre-treatment, ideal post-treatment—as planned on digital setup—and real post-treatment models were analysed using VAM software (Vectra, Canfield Scientific, Fairfield, NJ, USA). Prescribed and real rotation, mesiodistal tip and vestibulolingual tip were calculated for each tooth and, subsequently, analysed by tooth type (right and left upper and lower incisors, canines, premolars and molars) to identify the mean error and accuracy of each type of movement achieved with the aligner with respect to those planned using the setup.ResultsThe mean predictability of movements achieved using F22 aligners was 73.6%. Mesiodistal tipping showed the most predictability, at 82.5% with respect to the ideal; this was followed by vestibulolingual tipping (72.9%) and finally rotation (66.8%). In particular, mesiodistal tip on the upper molars and lower premolars were achieved with the most predictability (93.4 and 96.7%, respectively), while rotation on the lower canines was the least efficaciously achieved (54.2%).ConclusionsWithout the use of auxiliaries, orthodontic aligners are unable to achieve programmed movement with 100% predictability. In particular, although tipping movements were efficaciously achieved, especially at the molars and premolars, rotation of the lower canines was an extremely unpredictable movement.

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Objective The stability of the transverse expansion in passive self-ligating bracket treatments is a debated topic in orthodontics. However, to date, only 3 reports are available in the literature, with the maximum follow-up of 3 years after the end of therapy. The present study aims to evaluate the stability of orthodontic treatment with self-ligating brackets in a 6-year follow-up period of time. Materials and methods A sample of 56 non-extractive cases (of whom 33 females, mean age 16.9, SD = 9.0 years) consecutively treated with Damon® system was retrospectively selected. All patients received fixed retainers from canine to canine in both arches at the end of treatment, and no removable retainers were provided. The mean values of the transverse intercusp, transverse centroid and transverse lingual distances were evaluated for all teeth from canines to second molars in both arches. Each measure was calculated at four timepoints: before treatment (T0), at the end of treatment (T1), one year after treatment (T2) and six years after treatment (T3). Transverse diameters were measured for all teeth, starting from the canines to the second molars, for a total of 1680 observations, and subsequently compared in order to evaluate intra-treatment and post-treatment modifications. Results There were increases in all transverse dental measurements during active treatment. A statistically significant (p < .05) reduction of the transverse diameter was found, for upper and lower premolars, from T1 to T3. Conclusion The 6-year follow-up analysis detected that the initial transverse expansion showed a statistically significant relapse in premolars. No relapse was detected at the level of canines, due to the presence of fixed retainers, and minimal at first molars.

Objectives: The purpose of this study was to evaluate whether there is a relationship between the alignment or misalignment of the marginal ridges of posterior teeth and the degree of resorption of interproximal alveolar bone. Material and Methods: Intraoral scans and bitewing radiographs were performed on 50 subjects. The bitewing radiographs were analyzed using the VixWinTM Platinum software, measuring the distance between the cementitious junction and the alveolar ridge at the interproximal level for 32 sites for each patient, defined as bitewing scores. The digital models have been oriented in the three dimensions using the Rhinoceros 3D and the linear distance between two contiguous marginal ridges was measured for each interproximal space. To estimate the entity of the correlation, a separate linear regression was performed on the bitewing score for each mouth quadrant. Using the t-test the significance of each estimated coefficient was determinate (P < 0.05). Results: In the general comparison including all the analyzed elements, the independent variables are partially correlated with each other. Apparently, the relationship between independent and dependent variables appears to be insignificant. Comparing groups of teeth, however, there seems to be a statistically significant correlation (P < 0.05) between canine and lower first premolar in the XZ and YZ planes and between lower first and second molars in the three dimensions. Conclusion: There seems to be a poor correlation at a general level between periodontal conditions of the alveolar bone and the degree of alignment of the marginal ridges.

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