Background The influence of different biological agents on the rate of orthodontic tooth movement (OTM) has been extensively reviewed in animal studies with conflicting results. These findings cannot be extrapolated from animals to humans. Therefore, we aimed to systematically investigate the most up-to-date available evidence of human studies regarding the effect of the administration of different biological substances on the rate of orthodontic tooth movement. Methods A total of 8 databases were searched until the 16th of June 2020 without restrictions. Controlled randomized and non-randomized human clinical studies assessing the effect of biological substances on the rate of OTM were included. ROBINS-I and the Cochrane Risk of Bias tools were used. Reporting of this review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results A total of 11 studies (6 randomized clinical trials and 5 prospective clinical trials) were identified for inclusion. Local injections of prostaglandin E1 and vitamin C exerted a positive influence on the rate of OTM; vitamin D showed variable effects. The use of platelet-rich plasma and its derivatives showed inconsistent results, while the local use of human relaxin hormone showed no significant effects on the rate of OTM. Limitations The limited and variable observation periods after the administration of the biological substances, the high and medium risk of bias assessment for some included studies, the variable concentrations of the assessed biological agents, the different experimental designs and teeth evaluated, and the variety of measurement tools have hampered the quantitative assessment of the results as originally planned. Conclusions and implications Despite the methodological limitations of the included studies, this systematic review provides an important overview of the effects of a variety of biological agents on the rate of tooth movement and elucidates the deficiencies in the clinical studies that have been conducted so far to evaluate the effectiveness of these agents in humans, providing some guidelines for future robust research. Trial registration PROSPERO (CRD42020168481, www.crd.york.ac.uk/prospero)

Summary Objective The aim of this study was to evaluate and compare the amount of external apical root resorption (EARR) observed during the orthodontic treatment with pre-adjusted edgewise appliance (PEA) or clear aligner therapy (CAT) and with 2D or 3D radiographic methods of measuring the root resorption. Search strategy and selection criteria A search of PubMed MEDLINE, Scopus, Cochrane Central Register of Controlled Trials, LILACS, Web of Science, Dissertations & Theses Global, ClinicalTrials.gov registry, and the ISRCTN Registry was performed. Studies that have evaluated the amount of root resorption in non-extraction cases using CAT or PEA were selected for the systematic review. A meta-analysis was performed for the amount of root resorption of permanent maxillary incisors using PEA or CAT treatment modalities by either 2D or cone-beam computed tomography radiographic examination. Data collection and analysis Database research, elimination of duplicate studies, data extraction, and risk of bias were performed by authors independently and in duplication. A random-effect meta-analysis followed by subgroup comparisons were performed to evaluate EARR. Results A total of 16 studies (4 were prospective and 12 were retrospective) were identified for inclusion in the systematic review. The mean root resorption for the permanent maxillary incisors was in the range from 0.25 to 1.13 mm (overall: 0.49 mm; 95% confidence interval [CI] = 0.24 to 0.75 mm). The mean root resorption difference between CAT and PEA was statistically significant (P < 0.05) for 12 but not for 21, 11, or 22. Limitations One of the drawbacks is a lack of good quality prospective studies, specifically randomized clinical trials in the literature. Conclusions and implications Neither PEA or CAT technique leads to clinically significant root resorption (1 mm) of the maxillary incisors. The amount of EARR of maxillary incisors is not significant in comparing two treatment modalities (PEA and CAT), except for 12, where the PEA group has significantly more EARR when compared to CAT. Registration The protocol for this systematic review was based on the Cochrane Handbook for Systematic Reviews of Interventions 5.1.0 and was registered at PROSPERO database (https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42018113051). This systematic review is reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement.

Objectives The primary objective was to compare the success and survival rates of palatal and buccal mini-implants for different locations and treatment requirements. The secondary objective was to evaluate risk factors influencing the survival of mini-implants. Materials and Methods In this retrospective cohort, records of 127 orthodontic patients with 257 mini-implants were included after imposing inclusion/exclusion criteria. Along with the implant failure data, factors such as age, sex, transverse location, anteroposterior location, and purpose of mini-implants were recorded. Kaplan–Meier survival analysis was used to draw the curves and a Nathan Mantel-David Cox test to compare variables. Results The failure rate of palatal mini-implants was 8.5%, whereas the failure rate for buccal shelf mini-implants was 68.7% (P < .0001). A significant difference was that the survival rates of palatal mini-implants were dependent on the purpose of the mini-implants and, for the buccal mini-implants, they were dependent on the skeletal malocclusion and location type of mini-implants (P < .05). Conclusions The overall survival rate of palatal mini-implants was high, at 91.5%. Of the buccal mini-implants, inter-radicular mini-implants had the highest survival rate for 12 (75.5%) and 24 (71.9%) months, while buccal shelf mini-implants had the lowest success and survival rates for 12 (31.3%) and 24 (20.8%) months. Class III malocclusion had the lowest survival rate for the buccal mini-implants (65.3% and 54.2%) for 12 and 24 months.

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Objectives To evaluate the long-term effects of mini-screw–assisted rapid palatal expansion (MARPE), rapid palatal expansion (RPE), and controls on the nasal cavity with cone-beam computed tomography (CBCT). Materials and Methods A total of 180 CBCT scans that were part of a previous randomized trial were evaluated retrospectively for 60 patients at pretreatment (T1), postexpansion (T2), and posttreatment (T3). Patients were randomly assigned into 3 groups: MARPE, RPE, and controls (time period T1 to T3; MARPE: 2 years 8 months; RPE: 2 years 9 months; control: 2 years 7 months). Nasal height, nasal length, nasion–ANS height, ANS–PNS length, pyriform height, and nasal septal deviation angle were measured. The changes in alar width, alar base width, anterior nasal cavity width, posterior nasal cavity width, maxillary intermolar width, and maxillary intercanine width were also evaluated. Results The alar base width, posterior nasal cavity width, anterior nasal cavity width, maxillary intercanine width, and maxillary intermolar width significantly increased (P < .05), and the nasal septal deviation angle significantly decreased (P < .05) in both the MARPE and RPE groups as compared with controls in the short term. In the long term, the nasal septal deviation angle was significantly decreased (P < .05) in the MARPE and RPE groups as compared with controls, and the posterior nasal cavity width was significantly increased (P < .05) in the MARPE group compared with the RPE group and controls. Conclusions MARPE and RPE led to a significant increase in the nasal cavity and alar base width compared with controls in the short term. In the long term, a significant increase was observed only in the posterior nasal cavity width with MARPE. Both MARPE and RPE led to a minimal decrease in nasal septal deviation angle in comparison with controls.

BackgroundThe objectives of this study were to check the reliability of the five angular and two linear parameters for sagittal maxillo-mandibular discrepancy and to compare and correlate angular parameters with the ANB angle, and the linear parameter with Wits analysis.MethodsThe pre-treatment and post-functional lateral cephalograms of 25 subjects (17 males, 8 females) with class II division 1 malocclusion treated with twin block functional appliance were selected. Five angular (ANB, β angle, APDI, YEN angle, W angle) and two linear (Wits analysis, App-Bpp) parameters were traced on both sets of cephalograms. Paired Student’s t-test, one-way ANOVA, post hoc test, and Karl Pearson correlation statistical analysis were performed.ResultsAll the parameters considered in our study showed highly significant difference in pre-treatment and post-functional values, suggesting their reliability (p < 0.0001). When ANB angle was compared with the other angular parameters, a highly significant change in the mean value of the difference in pre-treatment (T1) and post-functional (T2) values was noted (p < 0.001). No significant change was seen when comparing the mean value of the difference in T1 and T2 between linear parameters (p = 0.949).ConclusionsAll the parameters used in the study can be reliably used to assess anteroposterior skeletal discrepancy. Whenever limitations of the ANB angle and Wits analysis are foreseen, the W angle and App-Bpp, respectively, can be reliably used. The YEN angle may reliably predict the post-functional change with the use of twin block appliance.

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