Efficacy of an innovative Herbst appliance with TADs for patients with hyperdivergent class II malocclusion: study protocol for a randomised controlled trial.

INTRODUCTION: Class II treatment with mandibular retrusion often involves the Herbst appliance due to its efficiency and low requirement of cooperation. Despite its advantages, it causes side effects concerning the occlusal plane and pogonion in terms of clockwise rotation that hinder the desired mandibular advancement for hyperdivergent patients. In this study, we will use a newly designed Herbst appliance, and a protocol that is accompanied by TADs for vertical control to avoid maxillary clockwise rotation. We hypothesise that the effect of the Herbst appliance with the vertical control approach will be beneficial for maintaining or even decreasing the skeletal divergence in hyperdivergent class II patients compared with conventional Herbst treatment. METHODS AND ANALYSIS: This study is a randomised, parallel, prospective controlled trial that will study the efficacy of Herbst with or without vertical control in children with hyperdivergent skeletal class II malocclusion. A total of 44 patients will be enrolled and randomised in a ratio of 1:1 to either Herbst treatment or Herbst treatment with vertical control. Participants will be recruited at the Shanghai Stomatological Hospital, Shanghai, China. The primary endpoint is the change in the angle indicating the occlusal plane and Sella-Nasion plane from baseline (T0) to the primary endpoint (T2) on cephalometric measurements by lateral X-ray examination. Important secondary outcomes include the root length of the anterior teeth, and the assessment score of the Visual Analogue Scale Questionnaire, etc. Safety endpoints will also be evaluated. ETHICS AND DISSEMINATION: This study has been approved by the ethics committee of the Shanghai Stomatological Hospital (Approval No. (2021) 012). Before enrolment, a qualified clinical research assistant will obtain written informed consent from both the participants and their guardians after full explanation of this study. The results will be presented at national or international conferences and published in peer-reviewed journals. TRIAL REGISTRATION NUMBER: ChiCTR2100049860, Chinese Clinical Trial Registry.

Tomographic evaluation of mandibular buccal shelf in patients with different vertical growth pattern / Evaluación de la placa ósea mandibular en pacientes con diferente patrón de crecimiento vertical

The purpose of this research was the tomographic evaluation of the Mandibular Buccal Shelf (MBS) in orthodontic patients with different vertical growth pattern. An observational, descriptive, cross-sectional and retrospective study was conducted. Tomographic images of patients aged 14 to 40 years were observed and a database was formed with those that met the inclusion criteria. The sample size was 10 for each group according to vertical growth pattern (hypodivergent, normodivergent and hyperdivergent). Then four zones of frequent insertion of extralveolar mini-screws were selected in the MBS, taking as a reference the mesial and distal roots of the first and second mandibular molar. When comparing the characteristics of MBS between vertical growth patterns, between sexes and hemiarchs, no statistically significant differences were found. However, when the characteristics of MBS were compared according to the reference root, it was found that there were statistically significant differences. The vestibular area to the distal root of the second mandibular molar presented the highest values in terms of angulation, height and thickness. There are no significant differences in the bone characteristics of MBS according to vertical growth patterns, sexes or hemiarchs. Angulation, height and thickness progressively increase from the vestibular bone of the mesial root of the first mandibular molar to the distal root of the second molar.

El propósito de esta investigación fue la evaluación tomográfica de la placa ósea mandibular (POM) en pacientes de ortodoncia con diferente patrón de crecimiento vertical. Se realizó un estudio de tipo observacional, descriptivo, transversal y retrospectivo. Se observó imágenes tomográficas de pacientes de 14 a 40 años de edad y se formó una base de datos con las que cumplían los criterios de selección. El tamaño de muestra fue de 10 para cada grupo según patrón de crecimiento vertical (hipodivergentes, normodivergentes e hiperdivergentes). Luego se seleccionaron cuatro zonas de inserción frecuente de minitornillos extralveolares en la POM, tomando como referencia las raíces mesial y distal del primer y segundo molar mandibular. Al realizar la comparación de las características de la POM entre patrones de crecimiento vertical, entre sexos y hemiarcadas no se encontraron diferencias estadísticamente significativas. Sin embargo, cuando se comparó las características de la POM según la raíz de referencia se encontró que había diferencias estadísticamente significativas. La zona vestibular a la raíz distal de la segunda molar mandibular presento los mayores valores en cuanto angulación, altura y grosor. No existen diferencias significativas en las características óseas de la POM según patrones de crecimiento vertical, sexos o hemiarcadas. La angulación, la altura y el grosor aumenta progresivamente desde el hueso vestibular de la raíz mesial del primer molar mandibular hacia la raíz distal del segundo molar.

Mechanical Properties of Mini-Implants Used in Extra-Radicular Anchorage

ABSTRACT Objective: To evaluate the mechanical properties of mini-implants (MIs) manufactured from stainless steel and compare them with conventional titanium-aluminum-vanadium alloy MIs. Material and Methods: The following groups were formed: G1 (n=24), 8×1.5 mm steel MIs; G2 (n=24), 12×2.0 mm steel MIs; and G3 (n=24), 10×1.5 mm titanium MIs. The 72 MIs were inserted in the infra zygomatic crest region of the maxilla and retromolar trigone in the jaw of 10 pigs. Pull-out, insertion torque, fracture and percussion tests were performed in order to measure the tensile strength, primary stability and fracture strength of MIs. A digital torque gauge was used to measure insertion and fracture torque, a universal mechanical testing machine was used for pull-out testing and a periotest device was used to measure the micromovement of MIs. For morphological and MI component evaluation, scanning electron microscopy (SEM) was performed. D'Agostino & Pearson, Kruskal-Wallis, and Dunn post-hoc and normality tests were used. Results: G2 insertion and fracture torques were significantly higher than G1 and G3 insertion and fracture torques (p<0.05). The pull-out and percussion tests presented similar values among the groups. SEM revealed that the fracture point was predominantly on the fourth thread for steel MIs (G1 and G2) and on the seventh thread for titanium-aluminum-vanadium MIs (G3). Conclusion: The mechanical properties of stainless steel MIs are superior to those of titanium-aluminum-vanadium alloy MIs.

Effects of Skeletally Supported Anterior en Masse Retraction with Varied Lever Arm Lengths and Locations in Lingual Orthodontic Treatment: A 3D Finite Element Study.

OBJECTIVE: This study is aimed at analyzing different points of force application during miniscrew supported en masse retraction of the anterior maxillary teeth to identify the best line of action of force in lingual orthodontic treatment. MATERIALS AND METHODS: Three-dimensional (3D) finite element models were created to stimulate en masse retraction with different heights and positions of the miniscrew and lever arm to change the force application points; a 150 g retraction force was applied from the miniscrew to the lever arms, and the initial tooth displacements were analyzed. RESULTS: Lingual crown tipping and occlusal crown extrusion were seen at all heights and positions of the miniscrew and lever arm, but when the miniscrew height was at 8 mm and the power arm was located between the lateral incisors and canines, these tipping patterns were less than those obtained with a 4.5 mm high miniscrew and a lever arm located distal to the canines. CONCLUSION: All miniscrew heights and lever arm positions showed initial lingual crown tipping and labial root tipping with occlusal crown extrusion. However, the 8 mm miniscrew height and the lever arm located between the lateral incisor and canine showed fewer amounts of these tipping patterns than a 4.5 mm miniscrew height and lever arm located distal to the canines. Therefore, this could be the preferred point of force application during en masse retraction in lingual treatment with additional torque control methods.

Consecutive use of mini-implants in the palate to treat skeletal maxillary constriction and Class II malocclusion in an adult case.

This report describes the successful use of two multifunctional mini-implants that were inserted into the palate in the treatment of an 18-year-old woman in whom the maxilla was skeletally narrowed and the molars have migrated mesially on both sides. Three different appliances were used in sequence in the course of treatment: first, an appliance supported by bone and teeth (hybrid hyrax) for surgically-assisted rapid maxillary expansion (SARME); second, a distalization device supported by mini-implants to achieve molar distalization; and third, a transpalatal arch (TPA) stabilized by mini-implants to allow indirect anchorage during retraction of the incisors. The mini-implants in the palate led to a reduction in the adverse effects of the SARME procedure and made treatment with cervical headgear unnecessary. TPA stabilized by the mini-implant was also used to retract the anterior teeth en masse, with no need for alterations in the treatment mechanism and using routine orthodontic methods.

Assessment of stiffness and load deflection of orthodontic miniscrews used for palatal anchorage: An in vitro biomechanical study.

OBJECTIVE: The purpose of this study was to evaluate the biomechanical properties of miniscrews of 5 different lengths, 2 different diameters, and different combinations of insertion used for palatal skeletal anchorage. MATERIALS AND METHODS: Twenty-four different combinations of a total of 120 miniscrews of two different diameters (2.0mm and 2.3mm) and five different lengths (9mm, 11mm, 13mm and 15mm) were tested at different angles of insertion (90° and 45°) and distances from a synthetic bone block (3mm, 5mm, 7mm). Samples were fixed in an Instron Universal Testing Machine and a load was applied in single cantilever mode to the neck of each miniscrew. The stiffness and maximum load before permanent deformation were recorded. Model-based recursive partitioning testing (CART) was used to evaluate differences between groups. RESULTS: Significantly higher forces were necessary to deform miniscrews of diameter 2.3mm than those of 2.0mm, those inserted at an angle of 45° with respect to 90°, and at smaller distances between the miniscrew neck and block; in addition, the maximum load and stiffness increased with increasing screw length. CONCLUSION: This in vitro experimental study showed strong correlations between deformation load and miniscrew geometry, insertion angle and distance from the synthetic block, results that should be considered when planning miniscrew insertion in order to reduce the risk of unwanted fracture.

Simulation of miniscrew-root distance available for molar distalization depending on the miniscrew insertion angle and vertical facial type.

OBJECTIVE: The purpose of this study was to evaluate the effects of miniscrew insertion angle and vertical facial type on the interradicular miniscrew-root distance available for molar distalization. MATERIALS AND METHODS: Cone-beam computed tomography images of 60 adults with skeletal Class I occlusion exhibiting hyperdivergent (n = 20), normodivergent (n = 20), and hypodivergent (n = 20) facial types were used. Placement of a 6-mm long, 1.5-mm diameter, tapered miniscrew was simulated at a site 4 mm apical to the cementoenamel junction, with insertion angles of 0°, 30°, 45°, and 60° relative to the transverse occlusal plane. The shortest linear distance between the miniscrew and anterior root at four interradicular sites was measured: maxillary second premolar and first molar (Mx 5-6), maxillary first and second molars (Mx 6-7), mandibular second premolar and first molar (Mn 5-6), and mandibular first and second molars (Mn 6-7). RESULTS: Miniscrew-root distance significantly increased as the insertion angle increased from 0° to 60°. In the mandible, the distances significantly differed among vertical facial types, increasing in the following order: hyperdivergent, normodivergent, and hypodivergent. The minimum mean distance was found in the Mx 6-7 (30°; 0.86±0.35 mm), and the maximum mean distance was found in the Mn 5-6 (60°; 2.64±0.56 mm). The rates of miniscrews located buccally outside the root distalization path were up to 70% and 55% when the miniscrews were placed at 60° insertion angles in the Mx 5-6 and Mn 5-6 regions, respectively. CONCLUSIONS: Miniscrew-root distance increased significantly with the increased insertion angle, and the amount of increase was affected by the miniscrew placement site and vertical facial type. To ensure adequate distalization of the posterior segment, the miniscrew should be inserted at an angle in the interradicular area between the second premolar and first molar.

Anatomical consideration for optimal position of orthodontic miniscrews in the maxilla: a CBCT appraisal.

BACKGROUND: Orthodontic miniscrews are commonly used as temporary anchorage devices. Bone thickness and bone depth are important factors when placing miniscrews. There are no studies to assess the maxillary bone thickness for optimum miniscrew placement in a Saudi population. OBJECTIVE: Assess the proximity of the maxillary sinus and nasal cavity in areas where miniscrews are usually inserted using cone beam computed tomography (CBCT). DESIGN: Retrospective, cross-sectional. SETTING: Department of maxillofacial radiology in a Saudi dental school. PATIENTS AND METHODS: Using CBCT images, we measured the distance between the maxillary sinus and nasal cavity to the palatal bone, buccal intra-radicular and infrazygomatic crest areas. Mean values (SD) were compared at various locations, including by gender, and correlation with age was calculated. MAIN OUTCOME MEASURE: Mean bone thickness at commonly used sites for orthodontic miniscrew placements in the maxilla. Secondary outcome was the insertion angle in the infrazygomatic crest area. SAMPLE SIZE: CBCT images of 100 patients (50 males and 50 females). RESULTS: The mean (standard deviation) age for the sample was 25.4 (6.5) years with no significant difference between males and females. In the palate, the distance to the nasal cavity and maxillary sinus was greater anteriorly and decreased significantly posteriorly (P<.001). Buccally, the interdental bone depth was significantly greater between the second premolar and first molar (11.96 mm) compared to between the central and lateral incisors (7.53 mm, P<.001). The mean bone thickness of the infrazygomatic crest area at a 45° insertion angle was 4.94 mm compared to 3.90 at a 70° insertion angle (P<.001). No correlation was found between age and bone thickness. CONCLUSION: The distance to the nasal cavity and maxillary sinus was greater in the anterior than posterior areas. There is minimal risk of injuring the maxillary sinus or nasal cavity using the buccal approach. Caution is needed when placing miniscrews in the infrazygomatic crest area. LIMITATIONS: Cross-sectional study from one center; hence, findings cannot be generalized to other populations. CONFLICT OF INTEREST: None.

Different approaches for management of Class III siblings: A long-term follow-up of two case reports.

Class III malocclusion can be varied in presentation and progression. This report describes the presentation, course of treatment and long-term follow-up of two siblings with Class III malocclusion. Two cases discussed in this report were different in their presentation. Sibling 1, a 19-year-old male patient had developed skeletal Class III malocclusion with severe maxillomandibular discrepancy, showing both components of maxillary hypoplasia and mandibular prognathism & asymmetry with average growth pattern. Sibling 2, a 13-year-old male patient had developed a Class III malocclusion with maxillary retrognathism with vertical growth pattern. An insight into the similarities and dissimilarities in the presentation, course of treatment and long-term follow-up of the two cases is provided. The two cases were successfully managed with entirely different treatment approaches. Sibling 1 underwent maxillary advancement with Le Fort I surgery and mandibular set back and rotation with bilateral sagittal split osteotomy which was preceded by pre-surgical orthodontic treatment with extraction of upper first premolars for orthodontic decompensation. Sibling 2 was treated with skeletally anchored facemask therapy followed by fixed mechanotherapy. Acceptable clinical outcome with long-term stability of the treatment results was observed in the two siblings. Orthognathic surgery may be completely avoided later if early orthopaedic treatment to advance the maxilla is initiated at an appropriate age.

Evaluation of insertion torque and surface integrity of zirconia-coated titanium mini screw implants.

INTRODUCTION: The aim of this study was to devise a modification of a temporary anchorage device (TAD) by coating titanium mini screw implants with yttrium stabilized zirconia and to evaluate the insertion torque and surface integrity of it. METHOD: Five titanium implants (Absoanchor, Dentos, South Korea) from each of the four groups comprising of 6 SH 13-08, 6 SH 13 -10 cylindrical and 6 SH 1312-08, 6 SH 1312-10 tapered mini screw implants were selected to be in the experimental group (Zr Ti) of implants, wherein they were coated with yttrium stabilised zirconia using a RF/DC magnetron sputtering unit. One mini screw implant from each of the four groups remained without coating to serve as control (Ti). After the coating of the titanium mini screw implants, scanning electron microscope (SEM) study was performed to evaluate the thickness and uniformity of the coating obtained. The insertion torque of all implants were evaluated by inserting the implant into bone sample using a manual torque wrench (ADIN). The implants were retrieved from the bone sample and a post insertion SEM study was performed to evaluate any changes in the surface of the Zr-Ti and Ti implants. X-ray diffraction (XRD) analysis was done to confirm the presence of Zirconia in the implants from the experimental group. RESULTS: There was no statistically significant difference between the insertion torque for the zirconia coated mini screw implants and the titanium mini screw implants, where the P value < 0.05 was considered as statistically significant. The values for insertion torque for Zr Ti cylindrical group of 8 mm length ranged from 19-20 N-cm and that for the tapered group of 8 mm length ranged from 15-17 N-cm. The insertion torque for the Zr Ti tapered group of 8 mm ranged from 21-22 N-cm and that of the tapered group ranged from 16-18 N-cm.The insertion torque values for the Ti cylindrical implant for length of 8 mm was 20 N-cm and 21 N-cm for length of 10 mm. The insertion torque values for the Ti tapered implant was 15N-cm for 8 mm length and 16N-cm for 10 mm length. CONCLUSION: The Zirconia coating on the Titanium mini screw implants was of 2.6 µm in thickness. There was no statistically significant difference in the insertion torque of the Zirconia coated mini screw implants and the non-coated titanium mini screw implants which retained their structural integrity.

Class II malocclusion and ectopic canine treated with Pendulum appliance and TADs in a high-relapse potential Ehlers-Danlos patient: A case report.

The aim of this case report is to present the treatment plan, progress, and retention difficulty of an adolescent with a skeletal Class II malocclusion and ectopic canine eruption using a Pendulum appliance and skeletal anchorage. The patient was diagnosed with benign hypermobile EDS towards the end of treatment. This patient went through frequent relapses in a short period, which should be considered while treating patients with similar condition. This report emphasizes that forces applied in patients with Ehlers Danlos Syndrome will accelerate tooth movement but the clinicians should be cautious enough to avoid potential periodontal breakdown due to disturbaces in collagen remodeling.

Early class III treatment with hybrid rapid palatal expander combined with facemask.

BACKGROUND: Class III patients are characterized by a deficiency of the maxilla and/or a prognathism of the mandible and require early treatment. DIAGNOSIS: This case report describes the treatment of a 5-year-old patient with a skeletal class III relationship, a significant mandibular symphysis deviation towards the right side and a different height of the mandibular angles. MANAGEMENT AND OUTCOME: The patient was treated with rapid maxillary expander combined with miniscrew, facemask and aligners. A functional and aesthetic occlusion in an improved facial profile was established at the end of the orthodontic treatment. Pre-treatment, post-treatment and one year retention records for the patient are presented. DISCUSSION: Class III patients require early treatment in order to optimize the traditional expander effects; subsequently hybrid anchorage allowed to maximize skeletal advancement. In addition, loss of space for the erupting teeth and dento-alveolar tipping were avoided. The good results of the phase I treatment and of the active retainer meant that a complex case would become relatively simple at the phase II treatment.

Class II malocclusion treatment changes with the Jones jig, Distal jet and First Class appliances.

Objective Maxillary molar distalization with intraoral distalizer appliances is a non-extraction orthodontic treatment used to correct molar relationship in patients with Class II malocclusion presenting maxillary dentoalveolar protrusion and minor skeletal discrepancies. This study compares the changes caused by three distalizers with different force systems. Methodology 71 patients, divided into three groups, were included. The Jones jig group (JJG, n=30; 16 male, 14 female, 13.17 years mean age) was treated with the Jones jig for 0.8 years. The Distal jet group (DJG, n=25; 8 male, 17 female, 12.57 years mean age) was treated with the Distal jet for 1.06 years. The First Class group (FCG, n=16; 6 male, 10 female, 12.84 years mean age) was treated with the First Class for 0.69 years. Intergroup treatment changes were compared using one-way ANOVA, followed by post-hoc Tukey's tests. Results Intergroup comparisons showed significantly greater maxillary incisor protrusion in DJG than in FCG (2.56±2.24 mm vs. 0.74±1.39mm, p=0.015). The maxillary first premolars showed progressive and significantly smaller mesial angulation in JJG, FCG and DJG, respectively (14.65±6.31º, 8.43±3.99º, 0.97±3.16º; p<0.001). They also showed greater mesialization in JJG than FCG (3.76±1.46 mm vs. 2.27±1.47 mm, p=0.010), and greater extrusion in DJG compared to JJG (0.90±0.77 mm vs 0.11±0.60 mm, p=0.004). The maxillary second premolars showed progressive and significantly smaller mesial angulation and mesialization in JJG, FCG and DJG, respectively (12.77±5.78º, 3.20±3.94º, -2.12±3.71º and 3.87±1.34 mm, 2.25±1.40 mm, 1.24±1.26 mm, respectively; p<0.001). DJG showed smaller distal angulation of maxillary first molars (-2.14±5.09º vs. -7.73±4.28º and -6.05±3.76º, for the JJG and FCG, respectively; p<0.001) and greater maxillary second molars extrusion (1.17±1.41 mm vs -0.02±1.16 mm and 0.16±1.40 mm, for the JJG and FCG, respectively; p=0.003). Overjet change was significantly larger in DJG compared to FCG (1.79±1.67 mm vs 0.68±0.84; p=0.046). Treatment time was smaller in FCG (0.69±0.22 years vs 0.81±0.33 years and 1.06±0.42 years, comparing it with the JJG and DJG, respectively; p=0.005). Conclusion The three appliances corrected the Class II molar relationship by dentoalveolar changes. The Distal jet produced smaller molar distal angulation than the Jones jig and First Class. The First Class appliance showed less anchorage loss, greater percentage of distalization and shorter treatment time than the Jones jig and Distal jet.

Increased tooth mobility after fixed orthodontic appliance treatment can be selectively utilized for case refinement via positioner therapy - a pilot study.

BACKGROUND: Increased tooth mobility persists after fixed orthodontic appliance removal, which is therapeutically utilized for post-treatment finishing with positioners. As such a fine adjustment is only required for selected teeth, the aim of this pilot study was to investigate tooth mobility in vivo on corrected and uncorrected subgroups under positioner therapy. METHODS: Mobility was measured on upper teeth of 10 patients (mean age 16.8) by applying loadings for 0.1, 1.0 and 10.0 s with a novel device directly after multibracket appliance debonding as much as 2d, 1, 2 and 6 weeks later. Positioners were inserted at day 2. Specimens were divided into Group C (teeth corrected via positioner), Group N (uncorrected teeth adjacent to teeth from group C), and Group U (uncorrected teeth in an anchorage block). Untreated individuals served as controls (n = 10, mean age 22.4). Statistics were performed via Kolmogorov-Smirnov test and Welch's unequal variances t-test for comparisons between groups. P < 0.05 was considered statistically significant. RESULTS: After 1 week, tooth mobility in Group U almost resembled controls (13.0-15.7 N), and reached physiological values after 6 weeks (17.4 N vs. 17.3 N in controls). Group C (9.0-13.4 N) and Group N (9.2-14.7 N) maintained increased mobility after 6 weeks. Tooth mobility was generally higher by reason of long loading durations (10.0 s). CONCLUSIONS: Positioner therapy can selectively utilized increased tooth mobility upon orthodontic fixed appliance treatment for case refinements. Here, uncorrected teeth in anchorage blocks are not entailed by unwanted side effects and recover after 6 weeks post treatment. Corrected teeth and their neighbors exhibit enhanced mobility even after 6 weeks, which represents a necessity for the proper correction of tooth position, and concurrently arouses the requirement for an adequate retention protocol.

Long term skeletal and dental changes between tooth-anchored versus Dresden bone-anchored rapid maxillary expansion using CBCT images in adolescents: Randomized clinical trial.

OBJECTIVE: The aim of this study was to determine long-term skeletal and dental changes in tooth-anchored versus Dresden bone-anchored rapid maxillary expansion using CBCT images in adolescents. MATERIALS AND METHODS: In all, 29 adolescent patients (11-17 years of age) needing skeletal expansion were randomly allocated to two different groups treated by either a Dresden bone-anchored expander or a conventional hyrax expander. Patients included did not have previous orthodontic treatment, were non-syndromic and had all teeth present in mouth. CBCT images were taken before expansion and two or more years after expansion. An independent T-test was used to determine the statistical significance between treatment groups and paired T-test was used to compare the results before and after expansion in each group. RESULTS: Neither treatment group showed overall long-term different skeletal and dental changes in the transverse, anterior-posterior and vertical planes (P<0.05). Both treatment groups showed mild asymmetric skeletal expansion, but these were clinically insignificant. CONCLUSIONS: Both expanders had similar skeletal and dental results. The greatest changes were in the transverse plane. Changes in vertical and anterior-posterior were negligible.

Risk factors for orthodontic mini-implants in skeletal anchorage biological stability: a systematic literature review and meta-analysis.

The reason of the biological stability loss of mini-implants is still a matter of discussion between dentistry professionals. The main objective of this systematic literature review and meta-analysis was to analyze the risk factors that prejudice this loss. A search was made in the electronic databases Pubmed, Scopus, Embase and Cochrane, in addition a manual search was made too in Grey Literature (Opengrey). No limits were set on the year of publication or language. The inclusion criteria were: studies in humans treated with fixed appliances with mini-implants, where the risk factors for secondary stability were evaluated for a minimum of 8 weeks. After eliminating duplicate studies and assessing which ones achieve the inclusion criteria, a total of 26 studies were selected for the qualitative synthesis, 18 of them were included in the quantitative synthesis. Common risk variables were compared in all of them. Analyzing the forest and funnel plots, statistically significant differences were obtained only for location, the upper maxilla having lower risk than the mandible with an odds ratio of 0.56 and confidence interval of 0.39 to 0.80. Prospective studies under controlled conditions should be required in order to obtain a correct assessment of the variables analyzed.

Una Descripción General y Actualizada de Miniplacas y Minitornillos. Efectos Dentoalveolares y Esqueléticos / A General and Updated Description of Miniplates and Miniscrews. Dentoalveolar and Skeletal Effects

RESUMEN: En ortodoncia, las miniplacas se utilizan como dispositivo de anclaje temporal (TAD) para la realización de movimientos dentales que permiten el uso de fuerzas ortopédicas en ellos. En comparación con los mini tornillos, las miniplacas tienen la ventaja de una tasa de falla muy baja, pero la desventaja es que para la extracción se necesita el mismo acto quirúrgico que se realizó para la instalación. El objetivo de este estudio es realizar una revisión bibliográfica de las indicaciones de miniplacas en pacientes con mordidas abiertas, clase II y anomalías de clase III, y buscar cómo las miniplacas han mejorado los tratamientos de ortodoncia. La información principal se reunió buscando en PubMed con las palabras clave enumeradas a continuación. Afirmamos que las miniplacas están indicadas para la retracción en masa de la arcada, donde se observó que la fuerza de 150 g aplicada en los molares superiores es suficiente no solo para empujar los molares hacia atrás en una clase I corregida, sino también para iniciar la retracción de premolares, caninos e incisivos. En pacientes con mordida abierta, las miniplacas se definen como un método seguro, una alternativa rápida y menos costosa a la cirugía ortognática. Y en pacientes de las clases II y III se utilizan sin producir efectos dentoalveolares que sustituyan a los dispositivos extraorales como máscaras, con dispositivos intraorales y elásticos (BAMP).

ABSTRACT: In orthodontics, miniplates are used as a Temporary Anchoring Device (TAD) for the purpose dental movements, allowing the use of orthopedic forces. In comparison with mini-screws, miniplates have the advantage of a very low rate of failure. Nonetheless, their removal requires the same surgical procedure as during installation, which is an obvious disadvantage. The aim of this study is to review the indications of miniplates in patients with open bite, class II and class III anomalies, and review how miniplates improved orthodontics treatments. Information was obtained by a search in PubMed with the keywords listed below. Miniplates are indicated for retraction in mass of the arcade, where it was seen that the force of 150 g applied on maxillary molars, is sufficient not only to push the molars back into a corrected class I, but also to initiate retraction of premolars, canines, and incisors. In open-bite patients, mini plates, are achieved as a safe method, that is quick and a less expensive alternative to orthognathic surgery. Further, in class II and III patients they are used without producing dentoalveolar effects replacing extraoral devices as facemasks, with intraoral devices and elastics. (BAMP).

Transverse, vertical, and anterior-posterior changes between tooth-anchored versus Dresden bone-anchored rapid maxillary expansion 6 months post-expansion: A CBCT randomized controlled clinical trial.

OBJECTIVE: The main aim of this randomized clinical trial was to determine 3 dimensional skeletal and dental changes six months after the use of bone-anchored versus tooth-anchored rapid maxillary expanders in adolescents. The secondary aim was to determine the symmetrical or asymmetrical expansion pattern between both appliances. MATERIALS AND METHODS: Fifty adolescents with skeletally constricted maxilla (mean age 13-14 years) were randomly assigned into: Dresden B-RME, Hyrax T-RME, or untreated control groups. CBCT scans were taken at initial and expander removal (6 months). Three-dimensional references and treatment landmarks were identified. Orthogonal distances were calculated from those landmarks. The main outcome was to compare skeletal and dental changes in each group and the secondary outcome was to verify if these changes were symmetric or not. Data was analysed using descriptive statistics and repeated measure MANCOVA and MANOVA. RESULTS: Both treatment groups showed significant skeletal and dental expansion compared to controls. T-RME group had greater mean inter-molar crown expansion (5.66mm) than the B-RME group (4.17mm). Both T-RME and B-RME groups showed significant skeletal maxillary expansion compared to controls (mean 1.27mm and 1.31mm respectively, both p<0.01), although no significant difference was found between both appliances. B-RME group showed a lower ratio of dental to skeletal expansion than T-RME group. T-RME showed a symmetrical expansion pattern, whereas the B-RME showed an asymmetrical pattern relative to mid-sagittal plane. The extent of molar crown expansion was 1.84mm greater on the TAD-side compared to the Implant-side. T-RME group showed significant anterior movement of the maxillary first premolar and molar (1.5mm, p<0.05), and vertical dental extrusion (1.8mm). No significant dental vertical or anterior-posterior changes were noted in the B-RME group. CONCLUSIONS: T-RME and B-RME produced similar amounts of skeletal expansion. B-RME group produced a lower component of dental expansion. Due to the Dresden B-RME configuration, asymmetrical expansion was noted.

Maxillary molar distalization in treatment of angle class II malocclusion growing patients: Uncontrolled clinical trial.

OBJECTIVE: This study was conducted to evaluate the clinical effectiveness treatment effects of a simple buccal technique for maxillary molar distalization using direct buccal skeletal anchorage. MATERIALS AND METHODS: After sample size calculation, fourteen female patients with bilateral Class II molar relationship (age 11-14 years) were selected from the clinic of the Department of Orthodontics, Faculty of Dentistry, Mansoura University, Egypt. After the application of the eligibility criteria, only eleven patients remained to final evaluation. The criteria included: erupted second maxillary molars, mild to moderate maxillary crowding not exceeding 6mm with/without increased overjet and non-extraction treatment in the lower arch. After alignment and levelling, a miniscrew (1. 8mm diameter - 0. 8mm long) was placed buccally between the maxillary second premolar and the first molar in each side. The maxillary molar distalization was done using 250 grams of force produced from NiTi closed coil spring stretched to a buccal miniscrew. Records including cephalometric x-rays and study casts were taken for all patients before and after molar distalization. Statistical evaluation was performed for the data obtained from analysis of cephalometric tracing and cast photocopies. RESULTS: The maxillary first molars were distalized with a rate of 0. 89±0. 30mm (95% CI 0.76-1.02) (P<0.001) and distalization amount of 4.09±0. 92mm (CI 3.68-4.50) (P<0.001). They were distally tipped by 2.48°±6. 16 (CI -0.26-5.21) (P=0.073) and rotated distopalatally by 11.89°±5.86 with negligible change in their vertical position about 0.11±0.63mm (CI -0.40-0.17) (P=0.411). There was no anchorage loss evident by the distal movement of all the maxillary teeth (P<0.001). Overjet significantly reduced by 0. 86±0. 50 (CI 0.52-1.20) (P=0.004). CONCLUSIONS: Maxillary molar distalization using a closed coil and buccal miniscrew is an effective and non-compliance dependent technique in a relatively short time.

Comparison of bone thickness in infrazygomatic crest area at various miniscrew insertion angles in Dravidian population - A cone beam computed tomography study.

INTRODUCTION: Infrazygomatic crest miniscrews are an important advancement in the field of orthodontics for anchorage reinforcement. The size of the miniscrews and the site of placement depend on the bone thickness in the infazygomatic crest area. The bone morphology and the thickness vary among different ethnicities of population. OBJECTIVES: To assess the bone thickness in the infrazygomatic crest area around the distobuccal root of the maxillary first molar using cone beam computed tomography and determine the best possible site and angulation for the placement of the miniscrew. Therefore, to determine the size of the implant that will suit the Dravidian population. METHODS: The infrazygomatic crest bone thickness was evaluated on 10 patients using cone beam computed tomography. The measurements were made along the distobuccal root of maxillary first molar at different angulations ranging from 75° to 40° to the occlusal surface of the molar. RESULTS: The infrazygomatic crest bone thickness was of 4.5mm to 9mm for the Dravidian population, when measured at an angle of 40° to 75° to the maxillary first molar occlusal plane and of 11 to 17mm above the occlusal plane. Student t-test (confidence interval 95%) was done to determine gender variation and compare the bone thickness of right and left side. ANOVA and post-hoc test were done to find the statistical difference between the bone thickness measured at different insertion angles. CONCLUSIONS: The best possible site for miniscrew insertion is 12 to 17mm above the occlusal plane at an angle of 65° to 70°, with no injury to the adjacent anatomical structures, no mucosal irritation and adequate stability for the miniscrew. The ideal infrazygomatic crest screw length for Dravidian population is 9 to 11mm.