The application of orthodontic bone stretching for correcting malpositioned dental implants.

BACKGROUND: Dental implants are sometimes initially placed in a wrong position leading to esthetic damage, which is difficult to solve with prosthetics. Moreover, implants placed in the anterior sector, like ankylosed teeth, are frequently found in a wrong position over time with infraocclusion because of continuous anterior alveolar growth. Different treatments have been proposed to manage the consequences of malpositioned dental implants. CASE PRESENTATION: This paper describes a surgical and orthodontic new procedure that can be used to relocate an implant in a wrong position: the Orthodontic Bone Stretching technique (OBS), which involves deep partial osteotomies combined with heavy orthodontic forces. The applied force facilitates esthetic rehabilitation with a movement towards the occlusal plane and can modify the implant axis and the gingival line alignment. This relocation is made possible thanks to a bone stretching phenomenon in the surgical area without immediate mobilization or repositioning of an alveolar segment. Three cases with the need for implant repositioning are presented here and were treated with the OBS technique. CONCLUSION: In the three cases presented, implant relocation was successfully performed with the OBS technique and the prosthetic crown was modified to improve esthetic results.

Orthodontic treatment of children with class II division 1 with severe MIH involving first permanent molars extractions: A case report.

BACKGROUND: Class II division 1 is the most common malocclusion in Europe. When the overjet is severe, the risk of trauma on anterior maxillary teeth as well as the risk of being bullied at school is increased. From this point of view, early treatment reduces the risk of dental fracture and increases patient self-esteem. In another hand, MIH is frequent with a prevalence of around 15% in children with country specificity, and molars in particular are difficult to treat endodontically with good long-term results when the MIH is severe. In many cases when the third molars are present, the extraction of the affected teeth followed by an orthodontic treatment remains the best solution but requires adequate orthodontic mechanics. OBJECTIVE: The purpose of this article is to display one case of class II division1 with MIH treated by orthopaedic therapy and followed by molar extractions and fixed appliance.

Incorrect measurements and misleading conclusions in the article "Comparison of the efficacy of tooth alignment among lingual and labial brackets: an in vitro study".

BACKGROUND/OBJECTIVE: To reproduce the methods and results of the study by Alobeid et al. (2018) in which the efficacy of tooth alignment using conventional labial and lingual orthodontic bracket systems was assessed. MATERIALS/METHODS: We used the identical experimental protocol and tested (i) regular twin bracket (GAC-Twin [Dentsply]) and lingual twin bracket systems (Incognito [3M]), (ii) together with NiTi 0.014" wires (RMO), and (iii) a simulated malocclusion with a displaced maxillary central incisor in the x-axis (2 mm gingivally) and in the z-axis (2 mm labially). RESULTS: The method described by Alobeid et al. (2018) is not reproducible, and cannot be used to assess the efficacy of tooth alignment in labial or lingual orthodontic treatment. Major flaws concern the anteroposterior return of the Thermaloy-NiTi wire ligated with stainless steel ligatures. The reproduced experimental setting showed that a deflected Thermaloy-NiTi wire DOES NOT move back at all to its initial stage (= 0 per cent correction) because of friction and binding (see supplemented video), neither with the tested labial nor with the lingual brackets. Furthermore, an overcorrection of up to 138 per cent, which the authors indicate for some labial bracket-wire combinations and which deserves the characterization "irreal", stresses the inappropriateness of the method of measurement.Further flaws include: a) incorrect interpretation of the measurement results, where a tooth tripping around (overcorrection) is interpreted as a better outcome than a perfect 100 per cent correction; b) using a statistical test in an inappropriate and misleading way; c) uncritical copying of text passages from older publications to describe the method, which do not correspond to this experimental protocol and lead to calculation errors; d) wrong citations; e)differences in table and bar graph values of the same variable; f) using a lingual mushroom shaped 0.013" Thermaloy-NiTi wire which does not exist; g) drawing uncritical conclusions of so called "clinical relevance" from a very limited in vitro testing. CONCLUSIONS: Clinical recommendations based on in vitro measurements using the Orthodontic Measurement and Simulation System (OMSS) should be read with caution.

Effectiveness of anchorage with temporary anchorage devices during anterior maxillary tooth retraction: A randomized clinical trial.

OBJECTIVE: This study evaluated the efficiency of anchorage provided by temporary anchorage devices (TADs) in maxillary bicuspid extraction cases during retraction of the anterior teeth using a fixed appliance. METHODS: Patients aged 12 to 50 years with malocclusion for which bilateral first or second maxillary bicuspid extractions were indicated were included in the study and randomly allocated to the TAD or control groups. Retraction of the anterior teeth was achieved using skeletal anchorage in the TAD group and conventional dental anchorage in the control group. A computed tomography (CT) scan was performed after alignment of teeth, and a second CT scan was performed at the end of extraction space closure in both groups. A three-dimensional superimposition was performed to visualize and quantify the maxillary first molar movement during the retraction phase, which was the primary outcome, and the stability of TAD movement, which served as the secondary outcome. RESULTS: Thirty-four patients (17 in each group) underwent the final analysis. The two groups showed a significant difference in the movement of the first maxillary molars, with less significant anchorage loss in the TAD group than that in the control group. In addition, TAD movement showed only a slight mesial movement on the labial side. On the palatal side, the mesial TAD movement was greater. CONCLUSIONS: In comparison with conventional dental anchorage, TADs can be considered an efficient source of anchorage during retraction of maxillary anterior teeth. TADs remain stable when correctly placed in the bone during the anterior tooth retraction phase.

Shear bond strength of two 2-step etch-and-rinse adhesives when bonding ceramic brackets to bovine enamel.

AIM: The present study assessed a fracture analysis and compared the shear bond strength (SBS) of two 2-step etch-and-rinse (E&R) adhesives when bonding ceramic orthodontic brackets to bovine enamel. MATERIALS AND METHODS: Thirty healthy bovine mandibular incisors were selected and were equally and randomly assigned to 2 experimental groups. Ceramic brackets (FLI Signature Clear®, RMO) were bonded onto bovine enamel using an adhesive system. In group 1 (n=15), the conventional E&R adhesive (OrthoSolo®+Enlight®, Ormco) was used, and in group 2 (n=15), the new E&R adhesive limited to ceramic bracket bonding (FLI ceramic adhesive®: FLI sealant resin®+FLI adhesive paste®, RMO) was used. In order to obtain appropriate enamel surfaces, the vestibular surfaces of mandibular bovine incisors were flat ground. After bonding, all the samples were stored in distilled water at room temperature for 21 days and subsequently tested for SBS, using the Instron® universal testing machine. The Adhesive Remnant Index (ARI) scores were evaluated. Failure modes were assessed using optical microscopy at magnification ×40. A statistic data analysis was performed using the Mann-Whitney U-test (P<0.05). RESULTS: The test showed a significant difference (P=0.00155) between the two groups for the SBS values. Group 1 had significantly higher SBS values (9.79 to 20.83MPa) than group 2 (8.45 to 13.94MPa). Analysis of the ARI scores revealed that most of the failures occurred at the enamel/adhesive interface. A statistically significant difference was found for the ARI scores between the two groups (P=0.00996). Only two fractured brackets, which remained bonded onto the bovine enamel, were reported. Both occurred in group 1. CONCLUSION: When bonded to ceramic brackets, FLI ceramic adhesive® (RMO) was demonstrated to be very predictable and safe for clinical application in enamel bonding, whereas the results obtained with the conventional adhesive system (OrthoSolo®+Enlight®, Ormco) were less reproducible and revealed slightly excessive shear bond strength values.

Prevalence of the use of anchorage miniscrews among French orthodontists.

Since always, anchorage has raised frequent problems for orthodontists. Since the early 2000s, the use of anchorage miniscrews has spread on a vast scale among practitioners. For the first time, a broad epidemiological survey (733 exploitable responses) has looked into the habits of French orthodontists regarding the use of anchorage miniscrews. The survey reveals that the majority of French practitioners have adopted miniscrews in their daily practice (66%), particularly among those using the lingual technique. However, the number of patients concerned still remains small for most practitioners (fewer than 10 patients for 65% of users). Seventy-four percent of users are satisfied with their experience with miniscrews although a majority uses them exclusively in adults (64%). The movements most sought by miniscrew users are mesialization/distalization and intrusion/extrusion. Among non-users, 60% have never placed an anchorage miniscrew but are thinking about doing so, whereas 20% of practitioners have used them but have since abandoned them. Finally, 20% of non-users have never used anchorage miniscrews and do not intend to do so.

Components of overbite correction in lingual orthodontics: molar extrusion or incisor intrusion?

OBJECTIVE: The aim of this study was to evaluate the components of overbite correction with the lingual Incognito(®) technique. MATERIALS AND METHODS: The study was based on 45 files of patients with overbite treated with the Incognito(®) technique. The evaluation of overbite correction is assessed by comparing lateral cephalograms before and after treatment using QuickCeph 2000(®) software. All the statistical calculations were performed using Statview II software for Mac(®). RESULTS: The results revealed the efficiency of the Incognito(®) technique in overbite correction despite the absence of bite planes in the majority of cases. The components of this correction are, in order: intrusion of mandibular incisors, extrusion of mandibular molars, weak extrusion of maxillary molars and stability of the maxillary incisors. These were the results commonly found in previous studies on small samples. The study also demonstrated an increase of lower face height in extraction and non-extraction cases. CONCLUSION: The Incognito(®) technique is very efficient in overbite correction. As the main component of overbite correction is mandibular incisor intrusion, it seems crucial from the esthetic point of view to evaluate the smile line when overbite correction is needed.

Can extraction sites affect the profile?

Tooth extractions, apart from the third molars, which it seems is normal to extract today, have always given rise to controversy among orthodontists with both supporters and opponents. It is legitimate to raise the question regarding the need for extractions in our treatment plan and to opt for the first or second premolars as the extraction site, or even the first molars when the latter are decayed and the germs of the third molars are in place. Facial esthetic guides us in our treatment decisions but we must free ourselves from the so-called esthetic lines drawn up many years ago and, for the most part, on the basis of lateral headfilms and small study samples. Particular ethnic features are another major factor to be borne in mind, given that the vast majority of cephalometric standards were based on Caucasian populations. In this article, we will draw on clinical studies to illustrate the thinking behind the need for extractions and the choice of extraction sites.

Mechanical forces-induced human osteoblasts differentiation involves MMP-2/MMP-13/MT1-MMP proteolytic cascade.

Matrix metalloproteinase (MMP) family proteins play diverse roles in many aspects of cellular processes such as osteoblastic differentiation. Besides, mechanical forces that occur in 3D collagen gel promote the osteoblastic phenotype and accelerate matrix mineralization. Although MMPs have been involved in bone differentiation, the proteolytic cascades triggered by mechanical forces are still not well characterized. In this study, we have investigated the contribution of both proteolytic cascades, MMP-3/MMP-1 and MMP-2/MMP-13/MT1-MMP in the differentiation of human osteoblasts cultured in a floating type I collagen lattice (FL) versus an attached collagen lattice (AL). Compared to AL, contraction of human osteoblasts-populated FL led to a fast (1 day) induction of alkaline phosphatase (ALP), bone sialoprotein (BSP), osteoprotegerin (OPG), and Runx-2 expression. At day 4, osteocalcin (OC) overexpression preceded the formation of calcium-containing nodule formation as assessed by X-ray analyses. MMP-1 and MMP-3 were produced to similar extent by cells cultured in FL and AL, whereas contraction of collagen lattices triggered both mRNA overexpression of MMP-2, MMP-13, and MT1-MMP (i.e., MMP-14), and their activation as evidenced by Western blotting or zymographic analyses. Down-regulating MT1-MMP expression or activity either by siRNA transfection or supplementation of culture medium with TIMP-1 or TIMP-2 highlighted the contribution of that enzyme in OC, ALP, and OPG expression. MMP-2 and MMP-13 were more directly involved in BSP expression. So, these results suggest that the main proteolytic cascade, MMP-2/MMP-13/MT1-MMP, and more particularly, its initial regulator MT1-MMP is involved in osteoblast differentiation through mechanical forces.

Anticipating root displacements: unlocking new prospects.

OBJECTIVE: The aim of this study was to visualize and quantify root displacements in the bone base of a patient before orthodontic treatment and obtain an optimal set-up that would include information on both coronal and root movements. MATERIAL AND METHOD: Data from a patient's scan records, the initial plaster model and scanned set-up are migrated into the Amira® software for advanced mesh and surface analysis. Using this software, each tooth of the initial 3D-reconstruction scan is isolated then superimposed over that of the initial model. The set-up is then positioned onto the initial model at second molar level and dragged onto the initial 3D reconstruction. Lastly, the roots are repositioned on the crowns on the set-up. RESULTS: This study enabled the visualization and quantification of dental displacements (crowns and roots) from initial to expected final position in a three-dimensional space reconstruction. DISCUSSION-CONCLUSION: This technique, carried out routinely thanks to the advent of cone beam tomography, can help optimize orthodontic treatments, notably by anticipating root proximity issues during set-up preparation.

Towards slide enhancement with the titanium-molybdenum wire?

This study aims to improve the tribological properties of titanium-molybdenum wire. Following an analysis of the wire/bracket/ligation friction parameters and an overview of the technological research into means of reducing such friction,we set up several types of surface treatment in the laboratory by physical deposition in the vapor phase and using cold plasma technology. The specimens obtained underwent two types of tribological tests and were then subjected to traction and bending tests in order to determine the variations in their mechanical properties induced by the different types of treatment. For purposes of comparison, all the tests were conducted on untreated wire, TMA® Low-friction® wire and stainless steel wire and with two types of elastomeric ties. We were able to demonstrate some remarkable slide performances obtained using cold plasma nitriding while preserving the mechanical properties. A significant difference was observed relative to the other surface treatments.