Controllability of Social Networks and the Strategic Use of Random Information

This work is aimed at studying realistic social control strategies for social networks based on the introduction of random information into the state of selected driver agents. Deliberately exposing selected agents to random information is a technique already experimented in recommender systems or search engines, and represents one of the few options for influencing the behavior of a social context that could be accepted as ethical, could be fully disclosed to members, and does not involve the use of force or of deception. Our research is based on a model of knowledge diffusion applied to a time-varying adaptive network, and considers two well-known strategies for influencing social contexts. One is the selection of few influencers for manipulating their actions in order to drive the whole network to a certain behavior; the other, instead, drives the network behavior acting on the state of a large subset of ordinary, scarcely influencing users. The two approaches have been studied in terms of network and diffusion effects. The network effect is analyzed through the changes induced on network average degree and clustering coefficient, while the diffusion effect is based on two ad-hoc metrics defined to measure the degree of knowledge diffusion and skill level, as well as the polarization of agent interests. The results, obtained through simulations on synthetic networks, show a rich dynamics and strong effects on the communication structure and on the distribution of knowledge and skills, supporting our hypothesis that the strategic use of random information could represent a realistic approach to social network controllability, and that with both strategies, in principle, the control effect could be remarkable

Class I and Class II Patients Treated with Damon System: A Study of Transversal, Sagittal and Torque Values Variations

Objective: To analyze the transversal and anterior-posterior changes obtained in patients treated only with the Damon system. Material and Methods: 51 patients with either class I or class II division 1 sagittal relationship treated with the Damon system and the same archwire sequence were retrospectively selected. Dental casts of each patient before (T0) and after treatment (T1) were scanned and analyzed using NEMOCAST 3D software. Inter-molar, inter first-premolar, inter-second premolar and inter-canine distances were measured in both upper and lower arches. Initial and final lateral cephalograms were traced using the OrisCeph program. Pre and post-treatment measurements were compared using the t-test for repeated measurements. The Pearson Correlation Index and Linear Regression Analysis were used to determine the dependence between continuous variables. The significance level was set at 0.05. Results: Transversal diameters in the upper arch increase statistically significantly, especially in the bicuspid area. Initial intra-arch diameter was the only statistically significant variable correlated with the final expansion obtained. A linear negative correlation between the initial latero-posterior torque and the final expansion was observed in both arches. Conclusion: Using identical arches in patients with very different initial characteristics, the changes in bicuspids’ diameters remain the most predominant. Patients with initial more negative torque in the posterior region had a higher expansion amount

Comparative Analysis of Stiffness of Lingual Appliances: An in Vitro Study

Objective: To analyze and compare the stiffness of different lingual appliances with different archwires. Material and Methods: The three-point bending test was used to analyze the stiffness of the lingual archwires for the different lingual systems: eBrace, Harmony, Incognito, and STb. The deflection load curve of each archwire was obtained to evaluate how the section, the material and the manufacturer affect the elasticity and stiffness characteristics of the wires. The comparison of the stiffness between different systems was carried out through a factor variance analysis with three factors (manufacturer, cross-section, and material), followed by the post-hoc Tuckey test. Results: An increase in the system's rigidity was reported as the wire section increases, regardless of the manufacturer. The stainless steel archwires have ever higher stiffness values than NiTi and TMA. The STb wires of CuNiTi material, by virtue of the characteristics of the thermal wires, have flatter and lower load-deflection curves than the NiTi wires of other manufacturers. Conclusion: Archwires section and material showed a significant influence on the stiffness of the lingual systems. Archwires of the same section and material but different manufacturers show different load-deflection curves of stiffness

Direct and Indirect Bonding Techniques: A Systematic Review

Objective: To assess the scientific evidence on direct and indirect bonding techniques to analyse the differences related to treatment time, number of appointments and number of bracket detachments. Material and Methods: The MEDLINE and Cochrane Library databases were searched through to March 2021. Reference lists from the retrieved publications were also examined. The following article types that described data on the different types of direct and indirect bonding techniques in orthodontics were included: prospective and retrospective cohort studies, case-control studies and randomized controlled clinical trials (RCCTs). Two review authors independently assessed eligibility, extracted data, and ascertained the quality of the studies. Results: The search strategy initially resulted in 824 articles, and after a careful selection comprising the inclusion criteria, 12 articles were picked for the final review, specifically 2 cohort studies, 4 case-control studies and 6 RCCTs. The methodological quality was low in 4 studies, medium in 2, and high in 6 articles. Conclusion: The evidence currently available suggests that the use of computer-aided bonding is related to a reduction in treatment time and the number of appointments compared to direct and manual indirect bonding. However, the total bonding time for computer-aided bonding technique, including digital bracket placement, was longer than for direct bonding. Further high-quality RCTs on the differences between direct and indirect bonding are necessary to determine more precise data, as well as additional advantages and disadvantages

Dentoalveolar Effects Following Maxillary Expansion: Comparison Between Dental and Skeletal Anchorage

Objective: To compare the dento-alveolar effects between dental and skeletal anchored expansion devices to achieve maxillary expansion in different groups of patients: pure dental anchorage was used in growing patients and skeletal anchorage in adult patients. Linear, angular and volumetric parameters have been analysed. Material and Methods: 22 patients has been selected from the total archive of patients treated in the Orthodontics Department of the University of Ferrara, Italy, divided into 3 groups according to the appliance used to obtain the transversal maxillary correction. Digital files of the upper arch were obtained from scans performed using an intro-oral scanner before treatment (T0) and at the end of expansion (T1). Therefore, linear, angular and volumetric measurements have been performed. Results: There is a highly significant statistic variation of the 3-3, 4-4 and 6-6 diameter as a function of time. There was a statistically significant variation of the palatal vault angle and of the 6-6 distance at the cusp level as a function of time. Moreover, it appears that these parameters are reduced in the group with skeletal anchored expander. No tooth considered have encountered a statistically significant change in tip and torque values, no matter the type of RPE and the treatment time. For all patients, we have recorded the superimposition of the maxillary dental cast before and after treatment. Conclusion: In all patients, we obtained a resolution of the maxillary transverse deficit. Patients treated by pure skeletal anchored devices have recorded a less variations of palatal vault angle and the distance between first molar cusps, as if the expansion was gained more parallel. The expansion obtained showed reduced dental side effects, as tip and torque values haven’t changed in a statistically significant way

Comparison of Bracket Position Accuracy with Different CAD/CAM Indirect Bonding Systems

Objective: To evaluate the accuracy of three different digital bracket positioning systems, comparing vertical, mesiodistal and buccolingual accuracy. Material and Methods:  The same case was sent to Orapix, Insignia, and Orthocad systems and the brackets were bonded to the malocclusion models. Damon 3 MX brackets were used with all systems and the brackets were bonded to the models with the same bonding protocol and materials. The comparison of the position of each single bracket was made with digital photography, and ImageJ software was used to find the length in pixels and then convert it to hundredths of a mm for vertical, mesiodistal and buccolingual displacement, compared to the setup. Results: Insignia System reported the average higher vertical displacement (0.28 mm), compared with the other two appliances (0.22-0.23 mm), and showed the lowest average displacement for the mesiodistal and buccolingual positioning (0.14 and 0.07 mm, respectively). However, these slight bracket positioning variations between these bonding systems were not statistically different (p>0.05). Conclusion:  The three systems analyzed were shown to be accurate in positioning the brackets, and none of them was statistically better

In Vitro Study of Tooth Surfaces After Interproximal Enamel Reduction: Extraoral Scanner and SEM Analysis

Objective: To perform a morphological evaluation concerning the extent of interproximal enamel reduction (IPR) with different manual instruments in different types of teeth and a qualitative analysis of enamel surface characteristics at the contact point before and after IPR. Material and Methods: 40 freshly extracted, caries-free, and intact human teeth were used for the study (20 bicuspids and 20 incisors) and performed IPR just on the mesial surface. The morphological variation of contact point was evaluated by superimposed the stl file, obtained thanks to an extraoral scanner, at T0 and T1 for each tooth. Two types of strip were used, Intensiv Manual Ortho Strips Coarse/Medium and Steelcarbo Horico Strips. Teeth were then cut lengthwise, removed the most apical root portion and the mesial and distal halves were gilded and observed at different magnifications. Results: The morphological variation following stripping mainly depends on the extent of the stripping, while the diameter, the type of strip and the shape of the tooth itself do not appear to be relevant. The 500X and 1500X magnifications allowed to appreciate better the characteristics of the surface of the stripped enamel and the differences with the intact enamel. All teeth treated, independently from the kind of strip used, shows deep marks and grooves in the direction of stripping. In both cases, the enamel appears significantly damaged at great magnifications . Conclusion: Stripping always and inevitably leads to a change in the shape of the contact point and is directly correlated to the amount of stripping performed. The use of polishing after the removal of enamel interproximal is necessary in all cases

In Vitro Study of Tooth Surfaces After Interproximal Enamel Reduction: Extraoral Scanner and SEM Analysis

Objective: To perform a morphological evaluation concerning the extent of interproximal enamel reduction (IPR) with different manual instruments in different types of teeth and a qualitative analysis of enamel surface characteristics at the contact point before and after IPR. Material and Methods: 40 freshly extracted, caries-free, and intact human teeth were used for the study (20 bicuspids and 20 incisors) and performed IPR just on the mesial surface. The morphological variation of contact point was evaluated by superimposed the stl file, obtained thanks to an extraoral scanner, at T0 and T1 for each tooth. Two types of strip were used, Intensiv Manual Ortho Strips Coarse/Medium and Steelcarbo Horico Strips. Teeth were then cut lengthwise, removed the most apical root portion and the mesial and distal halves were gilded and observed at different magnifications. Results: The morphological variation following stripping mainly depends on the extent of the stripping, while the diameter, the type of strip and the shape of the tooth itself do not appear to be relevant. The 500X and 1500X magnifications allowed to appreciate better the characteristics of the surface of the stripped enamel and the differences with the intact enamel. All teeth treated, independently from the kind of strip used, shows deep marks and grooves in the direction of stripping. In both cases, the enamel appears significantly damaged at great magnifications . Conclusion: Stripping always and inevitably leads to a change in the shape of the contact point and is directly correlated to the amount of stripping performed. The use of polishing after the removal of enamel interproximal is necessary in all cases

Phonetic Alterations Caused by Different Lingual Appliances

Objective: To evaluate the differences in phonetic alterations caused by three different lingual appliances, all bonded in sequence on the same patients. Material and Methods: Lingual brackets (STb, Incognito and Harmony) were bonded from 1.3 to 2.3 with a 0.013 CuNiTi archwire. The text was formulated to evaluate the phonetic variations in a controlled context (logatomi) and more casual sentences. The recording of the text was performed at time t0 (before positioning the brackets), t1 (after positioning the brackets) and t2 (60 minutes after positioning the brackets). An ANOVA-type analysis was performed. Results: A significant correlation was confirmed between the effects of all the linguistic methods used compared to the absence of the same. The most influenced acoustic variables were the center of gravity of the acoustic spectrum of the analyzed sounds (CoG) and the number of zero crossings of the instantaneous amplitude curve of the considered signal. Conclusion: The effects deriving from the positioning of the various brackets were relatively contained: in some cases, for some subjects, for some consonants and in specific contexts, some brackets may occasionally be less invasive than others. However, no lingual system was systematically better than others regarding phonetic alterations

3D Assessment of the Correlation between Neonatal Morphology and Occlusal Outcomes in 5-Year-Old Patients with Complete Unilateral Cleft Lip and Palate

Objective: To exploit 3D measurement technology to determine any correlation between neonatal palate morphology and occlusal outcomes at five years in patients receiving surgery for unilateral cleft lip and palate (CLP). Material and Methods: Twenty-nine neonatal and 5-year models treated by the same surgeon using the same protocol for CLP correction were scanned using a high-resolution structured-light scanner and stored in stl format. Dedicated software was used to make linear and surface area measurements on the neonatal models, and each digitized 5-year model was assigned a Five-Year-Old (5YO) index score on three separate occasions by the same investigator. Results: Minimum, maximum, mean, standard deviation and standard error were calculated for each variable considered, and the Pearson coefficient was used to identify any correlations between neonatal variables and 5YO scores. Linear regression analysis showed that the only variable to approach significance was the posterior width of the cleft, which showed an R2 equal to 0.111, indicating that it accounts for 11% of the variability of the 5YO index. There was no other appreciable correlation between linear measurements, surface areas, or their inter-relationships. Conclusion: There is no correlation between neonatal morphological characteristics and occlusal outcomes at 5 years in CLP patients treated via the surgical protocol considered