Maxillary orthodontic expansion assisted by unilateral alveolar corticotomy and low-level laser therapy: a novel approach for correction of posterior unilateral cross-bite in adults

Introduction: The treatment of a true unilateral posterior crossbite often requires asymmetric maxillary expansion; however, this is challenging to achieve with conventional expansion methods because of several biomechanical limitations. In this paper, we introduce a new protocol for the treatment of a unilateral posterior crossbite in adults based on maxillary orthodontic expansion assisted by corticotomy and low-level laser therapy (LLLT) performed on the crossbite side. Methods: The study sample included 15 adults (8 females, 7 males) affected by a true unilateral posterior crossbite, with a mean age of 21.6 ± 3.1 years at the at the beginning of treatment. After the application of orthodontic appliances (palatal expander and self-ligating brackets), corticomy was performed at the buccal aspect of the crossbite side while LLLT was monthly administered up to the correction of the crossbite. The efficacy of the technique was evaluated through measurements performed on maxillary digital models. Results: All subjects reported successful correction of the posterior unilateral crossbite, and functional occlusion was achieved as well. The average expansion was greater at the crossbite side compared to the unaffected side and such difference was significant at the levels of first premolars (P < 0.05), second premolars (P < 0.05) and first molars (P < 0.05). Conclusion: Orthodontic maxillary expansion assisted by unilateral corticotomy and LLLT was effective in the treatment of the true unilateral crossbite

An immunohistochemical study of the human periodontal ligament during sperimental orthodontic movement

Orthodontic tooth movement is characterized by remodeling changes in dental and paradental tissues, including dental pulp, periodontal ligament (PDL), alveolar bone, and gingiva. These tissues, when exposed to varying degrees of magnitude, frequency, and duration of mechanical loading, express macroscopic and microscopic changes. The different modification of periodontal ligament during load deformation can be monitored by analysis of the expression of different collagen types, fibronectin and vascular endothelial growth factor. The aim of this study was to evalue PDL collagen types I and IV, fibronectin and vascular endothelial growth factor (VEGF) modification induced by application of a precalibrated and constant orthodontic strength at different stages of treatment. For the study we utilized a coilspring NiTi 50 gr. and in vivo samples of 20 maxillaries and mandibular premolars of patients aged from 13 to 18 years subject to orthodontic treatment. These teeth was extracted at 1, 7, 14, 21 and 28 days from application of force respectively. The extraction of the PDL was effectuated scarifying the radicular surface on the pressure and tension side. The results were compared with periodontal ligament samples of the normal homologous teeth (control). The periodontal ligament samples were fixed in 3% paraformaldehyde in a 0,2M phosphate buffer at pH 7,4. The following primary antibodies were used: anti collagen I, anti collagen IV, anti fibronectin and mouse monoclonal anti-VEGF. Section were then observed and photographed using Zeiss LSM 510 confocal microscope. Were analyzed fluorescence intensity and compared with the control side. The signal of type I collagen is negative in tension and pressure side after 1 day, showed an increased respect to control, in the tension and pressure side, until 7, 14 and 21 days. After this stage in both sides maintained the same values of the control. The immunofluorescence of type IV collagen is negative, in both sides, after 1 and 7 days. At 14, 21 and 28 days from treatment, increased gradually in pressure side and manteined the same values of the control in tension side. The observation of fibronectin showed strongly immunofluorescence at all stages of treatment. After 1, 7 and 14 days the immunofluorescence of VEGF is negative in pressure side, and positive in tension side. In the last observation periods at 21 and 28 days, VEGF signal showing, in both sides, significant increase when compared with the control group. These findings suggest that: the increase of collagen type I and fibronectin could indicate that the solicitation by orthodontic force could determinate an increase of metabolic activity in the periodontal ligament. The rapid modification after the start of tooth movement, suggest that VEGF may be involved in the early stages of periodontal remodeling during orthodontic tooth movement, when occur rapid changes in local blood circulation. The initial decrease of collagen type IV, indicate a loss of vascular component in the early stages of movement infact this protein is localized in perivessel zones

Does Low-Taper Root Canal Shaping Decrease the Risk of Root Fracture? A Systematic Review

Minimal root-canal preparation has been suggested to reduce the risk of root fracture, but as a result, satisfactory cleaning and shaping do not take place. Large-scale taper instrumentation can contribute to removing infected tissue; however, it may weaken the tooth structure. The aim of this systematic review is to evaluate whether root-canal shaping with low-taper instruments decreases the risk of root fracture, compared to high-conicity shaping. A search was performed on Ovid MEDLINE, PubMed, and the Web of Science. The inclusion criteria were: studies comparing the root fracture resistance of endodontically treated teeth, shaped with low- and high-conicity taper instruments, in human trials, and via in vitro study. The review includes all types of endodontically treated teeth, with various instrument tapers. The scientific search engines produced 328 results. Only 20 of the results were evaluated after screening. Based on the articles analyzed, it is not clear whether a taper difference can determine differences in root fracture resistance. No randomized controlled trial (RCTs) with long follow-ups have been published to date. It must also be taken into account that the in vitro studies do not consider the numerous differences that there are between in vitro and clinical evaluation. The review was registered on the PROSPERO website, with the protocol number CRD42020151451

Effects of Composite Attachments on Orthodontic Clear Aligners Therapy: A Systematic Review

This systematic review aims to highlight the differences between different clear aligner therapies that differ in the presence of attachments or in attachment configuration. Eight electronic databases were searched up to March 2020. Two authors independently proceeded to study selection, data extraction, and risk of bias assessment. The analysis of the results was carried out examining six groups of movements (mesio-distal tipping/bodily movement; anterior bucco-lingual tipping/root torque; posterior bucco-lingual tipping/expansion; intrusion; extrusion; rotation). Five clinical trials were selected and all of them showed a medium risk of bias. Literature showed that attachments mostly increase the effectiveness of orthodontic treatment with clear aligners, improving anterior root torque, rotation, and mesio-distal (M-D) movement; they are also important to increase posterior anchorage. However, some articles showed contradictory or not statistically significant results. Attachments also seem to improve intrusion, but the evidence about this movement, as well as extrusion, is lacking. No studies evaluated posterior bucco-lingual tipping/expansion. Further clinical trials are strongly suggested to clarify the influence of attachments and their number, size, shape, and position on each orthodontic movement

Midpalatal Suture Density Evaluation after Rapid and Slow Maxillary Expansion with a Low-Dose CT Protocol: A Retrospective Study

Background and objectives: The aim of the present paper is to use low-dose computed tomography (CT) to evaluate the changes in the midpalatal suture density in patients treated with rapid maxillary expansion (RME) and slow maxillary expansion (SME). Materials and Methods: Thirty patients (mean age 10.2 ± 1.2 years) were retrospectively selected from the existing sample of a previous study. For each patient, a low-dose computed tomography examination was performed before appliance placement (T0) and at the end of retention (T1), seven months later. Using the collected images, the midpalatal suture density was evaluated in six regions of interest. Results: No significant differences were found between the timepoints in the rapid maxillary expansion group. Three out of six regions of interest showed significant decreases between the timepoints in the slow maxillary expansion group. No significant differences were found in comparisons between the two groups. Conclusions: The midpalatal suture density showed no significant differences when rapid maxillary expansion groups were compared to slow maxillary expansion groups, suggesting that a similar rate of suture reorganization occurs despite different expansion protocols

Correlation between Mesio-Distal Angulation and Bucco.-Lingual Inclination of First and Second Maxillary Premolars Evaluated with Panoramic Radiography and Cone-Beam Computed Tomography

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

Skeletal and Dental Effectiveness of Treatment of Class II Malocclusion With Headgear: A Systematic Review and Meta-analysis

Objective: To evaluate the skeletal and dental effects of headgear treatment by systematically reviewing the best available scientific evidence. Materials and Methods: A survey of articles published up to February 2017 investigating the effects of headgear in the treatment of patients with class II malocclusion was performed using 19 electronic databases. Only randomized clinical trials and prospective controlled clinical trials investigating growing patients with class II malocclusion treated with headgear were included. Two authors performed independently study selection, data extraction, and risk of bias assessment. All pooled data analyses were performed using the random-effect model. Statistical heterogeneity was evaluated. Results: In total, 6 trials were included (4 randomized clinical trials and 2 prospective controlled clinical trials), grouping data from 337 patients (170 treated patients and 167 untreated controls). The ages of the patients varied across the studies, but the majority of the trials had a sample with an age range between 8 and 9 years. The times of daily wear of the appliance varied across studies from 8 to 14 h/d. The significant mean differences in treatment effects compared with the untreated controls were 121.41\ub0 per year for SNA angle cephalometric parameter (95% confidence interval [CI]: 122.25\ub0 to 120.56\ub0), 120.57 mm/y for anterior maxillary displacement (95% CI: 120.75 to 120.40 mm), 121.42\ub0 per year for ANB angle cephalometric parameter (95% CI: 122.12\ub0 to 120.72\ub0), and 121.31 mm/y for the overjet cephalometric parameter (95% CI: 122.34 to 120.29 mm). Conclusion: Headgear treatment is effective in restricting sagittal maxillary growth and reducing the overjet in the short term

Correlation between Oral Hygiene and IL-6 in Children

The aim of this study was to evaluate the correlation between marginal gingivitis, oral hygiene parameters, and interleukin-6 (IL-6) levels in gingival crevicular fluid of 40 children. The marginal periodontal pathology was evaluated by gingival index (GI). The status of oral hygiene was estimated by using patient hygiene performance (PHP), brushing frequency (BF), and plaque index (PI). IL-6 levels in gingival crevicular fluid were measured to evaluate the inflammation in marginal gingiva. PHP score showed a significant correlation with GI, BF, and PI. The groups based on PHP ranges were significantly related to IL-6 concentration in crevicular fluid

Walking on the Moon: A randomized clinical trial on the role of lower body positive pressure treadmill training in post-stroke gait impairment

: Body weight-supported treadmill training (BWSTT) can be usefully employed to facilitate gait recovery in patients with neurological injuries. Specifically, lower body positive pressure support system (LBPPSS) decreases weight-bearing and ground reaction forces with potentially positive effects on qualitative gait indices. However, which gait features are being shaped by LBPPSS in post-stroke patients is yet poorly predictable. A pilot study on the effects of LBPPSS on qualitative and quantitative gait indices was carried out in patients with hemiparesis due to stroke in the chronic phase. Fifty patients, who suffered from a first, single, ischemic, supra-tentorial stroke that occurred at least 6 months before study inclusion, were enrolled in the study. They were provided with 24 daily sessions of gait training using either the AlterG device or conventional treadmill gait training (TGT). These patients were compared with 25 age-matched healthy controls (HC), who were provided with the same amount of AlterG. Qualitative and quantitative gait features, including Functional Ambulation Categories, gait cycle features, and muscle activation patterns were analyzed before and after the training. It was found that AlterG provided the patients with higher quantitative but not qualitative gait features, as compared to TGT. In particular, AlterG specifically shaped muscle activation phases and gait cycle features in patients, whereas it increased only overall muscle activation in HC. These data suggest that treadmill gait training equipped with LBPPSS specifically targets the gait features that are abnormal in chronic post-stroke patients. It is hypothesizable that the specificity of AlterG effects may depend on a selective reshape of gait rhythmogenesis elaborated by the locomotor spinal circuits receiving a deteriorated corticospinal drive. Even though further studies are warranted to clarify the role of treadmills equipped with LBPPSS in gait training of chronic post-stroke patients, the knowledge of the exact gait pattern during weight-relief is potentially useful to plan patient-tailored locomotor training