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1.
BMC Med Educ ; 21(1): 326, 2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-34098931

RESUMO

BACKGROUND: Wire-bending skills is commonly taught through live demonstrations (LD) though flipped classroom (FC) method has gained popularity. Continuous formative assessment promotes personalised learning via closely monitored progress, with the identification of students' strengths and weaknesses. This study aims to evaluate the effects of LD and FC teaching methods, supplemented with continuous formative assessment, on dental students' learning of wire-bending skills for six types of removable orthodontic appliance components. A deeper understanding of the relative effectiveness between LD and FC teaching methods can help identify the most appropriate method to achieve student learning objectives, which is especially important given the current Covid-19 pandemic. METHODS: Forty third-year undergraduate dental students were randomly assigned into FC (n = 20) or LD (n = 20) cohort. Each student attended six teaching sessions, each to teach students' competency in fabricating one type of wire component, for a total competency in fabricating six wire components over the course of six teaching sessions. Either LD or FC teaching methods were used. After each session, wire assignments had to be submitted. Wire assignments were then evaluated using a blinded wire-bending assessment protocol. As part of their formative assessment, the assessment results were distributed to students, lecturers, and technicians before the next session. After the first session (T0) and at the end of all six sessions (T1), students completed a self-reported questionnaire. RESULTS: The mean wire-bending scores for FC were significantly higher than LD for two of the six assignments, namely the Adams clasp (p < 0.01) and Z-spring (p = 0.03). Scores for both LD and FC increased significantly over time, which may be attributed to formative assessment. There was no statistically significant correlation between wire-bending scores and video usage. Students were satisfied with both teaching methods, according to T0 and T1 questionnaires. CONCLUSIONS: Both LD and FC are equally effective in transferring practical orthodontic wire-bending skills and well-received by students. Continuous formative assessment may have enhanced students' learning of orthodontic wire-bending skills. Further studies with control group are recommended to investigate the effect of formative assessment on teaching practical dental skills.


Assuntos
COVID-19 , Estudantes de Odontologia , Avaliação Educacional , Humanos , Fios Ortodônticos , Pandemias , Aprendizagem Baseada em Problemas , SARS-CoV-2 , Ensino
2.
Dental Press J Orthod ; 26(2): e211945, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34008740

RESUMO

OBJECTIVE: This paper aims to verify the thermodynamic, mechanical and chemical properties of CuNiTi 35ºC commercial wires. METHODS: Forty pre-contoured copper-nickel-titanium thermodynamic 0.017 x 0.025-in archwires with an Af temperature of 35°C were used. Eight wires from five different manufacturers (American Orthodontics® [G1], Eurodonto® [G2], Morelli® [G3], Ormco® [G4] and Orthometric® [G5]) underwent cross-sectional dimension measurements, tensile tests, SEM-EDS and differential scanning calorimetry (DSC) tests. Parametric tests (One-way ANOVA and Tukey post-test) were used, with a significance level of 5%, and Pearson's correlation coefficient test was performed between the Af and chemical elements of the wires. All sample tests and statistical analyses were double-blinded. RESULTS: All wires presented standard dimensions (0.017 x 0.025-in) and superelastic behavior, with mean plateau forces of: G1 = 36.49N; G2 = 27.34N; G3 = 19.24 N; G4 = 37.54 N; and G5 = 17.87N. The Af means were: G1 = 29.40°C, G2 = 29.13°C and G3 = 31.43°C, with p>0.05 relative to each other. G4 (32.77°C) and G5 (35.17°C) presented statistically significant differences between each other and among the other groups. All samples presented Ni, Ti, Cu and Al in different concentrations. CONCLUSIONS: The chemical concentration of the elements that compose the alloy significantly influenced the thermodynamic and mechanical properties.


Assuntos
Ligas Dentárias , Fios Ortodônticos , Estudos Transversais , Elasticidade , Teste de Materiais , Estresse Mecânico , Titânio
4.
J Contemp Dent Pract ; 22(1): 27-33, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34002705

RESUMO

AIM: To evaluate the precision of the orthodontic bracket slot dimensions of 0.022 inch and to compare them with those of the manufacturers' specifications. MATERIALS AND METHODS: The slots of upper-right central incisor brackets (n = 5) from 11 commercial bracket systems of three different manufacturers (3M Unitek: Victory Mini Metal, Clarity, SmartClip, Clarity SL; ORMCO/SYBRON: Mini Diamond Twin, Damon Q, Damon Clear; Dentsply/GAC: Ovation, Mystique, In-Ovation R, In-Ovation C) were measured. The orthodontic brackets were scanned using micro-computed tomography (micro-CT), and the bracket slots were measured using micro-CT images. The slot was measured at four different surfaces (occlusal, gingival, base, and face) for both mesial and distal sites. Data were subjected to ANOVA and unpaired t-tests. A p-value of ≤0.05 was considered statistically significant. RESULTS: All brackets had slot dimensions that were significantly larger (p < 0.05) than the stated 0.022 inch. 3M-victory were 11.99% larger (0.02509 inch) and the closest to the stated dimension and the ORM-Damon C were 24.07% larger (0.02948 inch) than the quoted slot size of 0.022 inch. Comparison between mesial and distal sides showed that 91% of the bracket slots were asymmetrical at their bases and 100% asymmetrical at their faces. All of the bracket system showed divergent walls from base to face with values ranging from 1.96 (3M-SmartClip) to 26.58% (ORM-Damon C). CONCLUSION: The actual measurements of 11 bracket systems from three different manufacturers were more substantial than the manufacturers' specifications, and the walls of the slots diverged from the bracket bases in all of the tested bracket system. CLINICAL SIGNIFICANCE: Orthodontic bracket slots vary significantly from that of the manufacturers' specification. The orthodontist should anticipate such shortcomings and be able to modify treatment mechanics through additional wire bending in three spatial planes.


Assuntos
Braquetes Ortodônticos , Análise do Estresse Dentário , Teste de Materiais , Desenho de Aparelho Ortodôntico , Fios Ortodônticos , Aço Inoxidável , Microtomografia por Raio-X
5.
Dental Press J Orthod ; 26(2): e2119378, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33950082

RESUMO

OBJECTIVE: To determine whether separating the alignment and leveling phases can reduce proclination of the mandibular incisors. METHODS: Eligibility criteria included Class I subjects with an irregularity index of 3-5 mm, 3-4 mm curve-of-Spee (COS), and non-extraction treatment. Thirty adults were randomly allocated into two groups: (1) Control group was leveled and aligned simultaneously with flat archwires progressively to 0.016x0.022-in stainless-steel; (2) Experimental group was aligned first with 0.014-in-superelastic NiTi with mild accentuated COS, then leveled using 0.016x0.022-in beta-titanium accentuated COS archwires and gradually reduced the curve until flat. Mandibular incisor position and inclination were evaluated by cephalometric analysis. COS and irregularity index were evaluated in study models. Assessment was conducted twice after 0.016-in NiTi and after 0.016x0.022-in stainless-steel archwire placements. Dental changes from cephalograms and models were compared within group using paired t-test and between groups using independent t-test. RESULTS: Control group: Round-wire-phase, mandibular incisors tipped labially (4.38° and 1 mm) with intrusion (-1.13 mm); Rectangular-wire-phase, mandibular incisors further intruded and proclined (-0.63 mm and 1.38°). Experimental group: During aligning with round accentuated COS archwires, mandibular incisors tipped very slightly labially (0.75° and 0.50 mm) with no significant intrusion; during leveling with rectangular archwires, incisors majorly intruded (1.75 mm) with slight proclination (1.81°). The experimental group had significant less incisor proclination (control: 5.76°, experimental: 2.56°) with more incisor intrusion (control: -1.75 mm, experimental: -2.13 mm). The COS in experimental group showed significant greater reduction (-2.88 mm) than that of the control group (-1.69 mm). CONCLUSION: In control group, mandibular incisor proclination was markedly observed in round archwires, with further proclination caused by rectangular archwires. In experimental group, minimal proclination was exhibited when accentuated COS round archwires were used for aligning. Leveling with rectangular archwires caused less proclination with more COS reduction.


Assuntos
Incisivo , Técnicas de Movimentação Dentária , Cefalometria , Mandíbula , Fios Ortodônticos , Aço Inoxidável
6.
Dental Press J Orthod ; 26(2): e212020, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33950083

RESUMO

INTRODUCTION: After debonding, white spot may appear on the area below the bracket, which is the early clinical sign of carious lesion. There is increased caries risk underneath and adjacent to orthodontic bands and brackets, which call for maximum use of caries preventive procedures using various fluoride application methods. OBJECTIVE: The aim of the study was to evaluate alterations in the mechanical properties (modulus of elasticity and yield strength) in loading and unloading phases for different orthodontic archwires (nickel-titanium [NiTi] and copper-nickel-titanium [CuNiTi]) when exposed routinely to fluoride prophylactic agents for a predetermined period of time. METHODS: Preformed rectangular NiTi and CuNiTi wires were immersed in fluoride solution and artificial saliva (control) for 90 minutes at 37ºC. After immersion, specimens were tested using a 3-point bend test on a universal testing machine. RESULTS: There is a significant reduction in the unloading yield strength when the NiTi and CuNiTi wires were exposed to APF gel. CONCLUSION: The result suggests that use of topical fluoride agents affect the mechanical properties of the wires, leading to increase in treatment duration. Fluoride prophylactic agents must be used with caution in patients undergoing orthodontic treatment. Injudicious use of these agents may cause corrosive effects on the orthodontic wire surfaces, with alteration in their mechanical properties.


Assuntos
Níquel , Fios Ortodônticos , Cobre , Ligas Dentárias , Fluoretos , Humanos , Teste de Materiais , Níquel/efeitos adversos , Propriedades de Superfície , Titânio
7.
Am J Orthod Dentofacial Orthop ; 159(5): 660-665, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33714568

RESUMO

INTRODUCTION: The objective of this study was to evaluate in vitro and in vivo bacterial endotoxin (LPS) adhesion in polyurethane and silicone esthetic elastomeric orthodontic ligatures. The null hypotheses tested were: (1) there is no LPS adhesion in esthetic elastomeric orthodontic ligatures; and (2) there is no difference in the LPS adhesion between different brands of these ligatures. METHODS: For the in vitro study, 4 types of esthetic elastomeric ligatures were used (Sani-Ties and Sili-Ties [Dentsply GAC, Islandia, NY;] and Mini Single Case Ligature Stick and Synergy low-friction ligatures [Rocky Mountain Orthodontics, Denver, Colo]), contaminated or not with endotoxin solution. Replicas of twisted wire and cast stainless steel ligatures were used as control. For the in vivo study, 10 male and 10 female patients, aged 15-30 years, received the same 4 types of ligatures, 1 of each inserted in the maxillary and mandibular canines, randomly. Twenty-one days later, the ligatures were removed, and endotoxin quantification was performed using the Limulus amebocyte lysate test. Data were analyzed (α = 0.05) using the Kruskal-Wallis test and Dunn's posttest or analysis of variance and Tukey's posttest. RESULTS: GAC silicone group had the lowest median contamination (1.15 endotoxin units/mL; P <0.0001) in vitro. In the in vivo study, the GAC silicone group had the lowest mean contamination (0.577 endotoxin units/mL; P <0.001). In both studies, the other groups did not present a significant difference when compared with each other (P >0.05). CONCLUSIONS: LPS exhibited an affinity for all the tested polyurethane and silicone elastomeric ligatures. GAC silicone ligatures presented with lower amounts of LPS attached to their surfaces. Thus, both null hypotheses were rejected.


Assuntos
Braquetes Ortodônticos , Adolescente , Adulto , Elastômeros , Endotoxinas , Estética Dentária , Feminino , Fricção , Humanos , Masculino , Teste de Materiais , Desenho de Aparelho Ortodôntico , Fios Ortodônticos , Aço Inoxidável , Adulto Jovem
8.
Medicina (Kaunas) ; 57(2)2021 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-33671217

RESUMO

Background and objectives: The aim of this study was to evaluate the influence of friction on design of the type of bracket, patients' perception of pain and the impact on their oral health-related quality of life. Materials and Methods: A randomized clinical trial was carried out with 90 patients (62.2% women and 37.8% men) with three kinds of fixed multi-bracket appliances: Conventional (GC), fixed multi-bracket low friction (GS) and self-ligating (GA). The VAS (Visual Analogue Scale) was used to determine pain during the first seven days of treatment at different points in time. The patients were also given the OHIP-14 (Oral Health Impact Profile) questionnaire to analyse their oral health-related quality of life (OHRQoL) after the first 30 days of treatment. The ANOVA test was used for the analysis of the variables and the post hoc Bonferroni test for the comparison between groups. Results: Maximum pain was observed between one and two days after the start of treatment. The GC group showed the greatest degree of pain, with maximum values (4.5 ± 2.0) at 24 h. The self-ligation brackets show lower impact on patients' oral health-related quality of life (0.8 ± 2.2, p < 0.01). Conclusions: Friction in the type of bracket influences pain and the Oral Health-Related Quality of Life of patients who use multi-bracket fixed orthodontics.


Assuntos
Braquetes Ortodônticos , Qualidade de Vida , Fricção , Humanos , Teste de Materiais , Desenho de Aparelho Ortodôntico , Fios Ortodônticos
9.
BMC Oral Health ; 21(1): 87, 2021 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-33632190

RESUMO

BACKGROUND: The aim of this study is to compare the biomechanical effects of the conventional 0.019 × 0.025-in stainless steel archwire with the dual-section archwire when en-masse retraction is performed with sliding mechanics and skeletal anchorage. METHODS: Models of maxillary dentition equipped with the 0.019 × 0.025-in archwire and the dual-section archwire, whose anterior portion is 0.021 × 0.025-in and posterior portion is 0.018 × 0.025-in were constructed. Then, long-term tooth movement during en-masse retraction was simulated using the finite element method. Power arms of 8, 10, 12 and 14 mm length were employed to control anterior torque, and retraction forces of 2 N were applied with a direct skeletal anchorage. RESULTS: For achieving bodily movement of the incisors, power arms longer than 14 mm were required for the 0.019 × 0.025-in archwire, while between 8 and 10 mm for the dual-section archwire. The longer the power arms, the greater the counter-clockwise rotation of the occlusal plane was produced. Frictional resistance generated between the archwire and brackets and tubes on the posterior teeth was smaller than 5% of the retraction force of 2 N. CONCLUSIONS: The use of dual-section archwire might bring some biomechanical advantages as it allows to apply retraction force at a considerable lower height, and with a reduced occlusal plane rotation, compared to the conventional archwire. Clinical studies are needed to confirm the present results.


Assuntos
Procedimentos de Ancoragem Ortodôntica , Fios Ortodônticos , Fenômenos Biomecânicos , Análise de Elementos Finitos , Humanos , Técnicas de Movimentação Dentária
10.
Biomed Res Int ; 2021: 6611979, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33575329

RESUMO

Objective: Gummetal is a novel multifunctional alloy which possesses distinctive properties with the potential to refine and amend the efficacy of orthodontic treatment. The objective of this critical literature review was to investigate scientific evidence concerning the mechanical and clinical features of this recently manufactured beta-titanium orthodontic wire. Materials and Methods: Electronic databases: PubMed, PMC, Google Scholar, Ovid, and Cochrane Library were searched. Studies investigating the properties of Gummetal orthodontic wire including in vitro and clinical studies were selected, validity was assessed, and data was extracted. The risk of bias was assessed by the Cochrane risk of bias Tool 2.0 in a randomized clinical trial. Results and Discussion. Among 322 papers, 13 papers were selected and divided into two groups: prospective double-blinded randomized clinical trial and in vitro studies. Conclusions: The results of this review should be interpreted with caution because of the heterogeneity of the studies. Only single clinical trial paper was found in the literature. The studies reported different characteristics obtained by various methods; thus, it was difficult to objectively compare the results. Low bending strength, low fatigue limit, and high resilience have been confirmed. Gummetal provides lower force than Nitinol and TMA but higher than Supercable wire. Plastic deformation of Gummetal questions its superelasticity. Friction of Gummetal wire is comparable to SS and CoCr wires. Because of its nontoxic chemical composition, Gummetal might be useful in the initial phase of orthodontic treatment for patients suffering from nickel allergy. Further studies are necessary to assess the usefulness of Gummetal in the clinical practice.


Assuntos
Ligas , Braquetes Ortodônticos , Fios Ortodônticos , Titânio , Módulo de Elasticidade , Humanos , Resistência à Tração
11.
J Mech Behav Biomed Mater ; 116: 104323, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33494019

RESUMO

This work aims to assess the influence of corrosion on fracture of nickel titanium (NiTi) superelastic wires in physiological solutions (9 g/l NaCl) with and without addition of 1 g/l NaF. The electrochemical cell was coupled to a Hounsfield Tensiometer tensile machine commonly used for corrosion investigation of alloys under stress and strain. Corrosion tests were performed on unstrained and strained conditions up to 4% total strain. This strain limit corresponds to 50% of the total elongation achieved into the superelastic stress plateau of the alloy. All wire specimens were analyzed after testing by scanning electron microscopy (SEM). The results showed that localized corrosion occurred for NiTi wires in solution containing fluoride, while no corrosion attack was detected in NaCl 9 g/l solution. There was no significant difference between the corrosion resistance of unstrained and strained wires. However, brittle like fracture occurred in NaCl + NaF solution within the superelastic domain of the material. The most relevant conclusion achieved is that the use of superelastically strained NiTi in oral environments in the presence of fluoride is followed by significant risk of corrosion induced fracture.


Assuntos
Ligas , Fios Ortodônticos , Corrosão , Ligas Dentárias , Teste de Materiais , Microscopia Eletrônica de Varredura , Propriedades de Superfície , Titânio
12.
Angle Orthod ; 90(5): 634-639, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-33378478

RESUMO

OBJECTIVES: To examine the effect of micro-osteoperforation (MOP) on the space closure rate using passive self-ligating or conventional brackets. MATERIALS AND METHODS: This was a two-arm parallel randomized controlled trial undertaken at the outpatient department of a dental college. There were 60 participants (30 women and 30 men) who fulfilled the inclusion criteria. Both the study and control groups were subjected to MOPs throughout the period of space closure. MOPs were repeated every 28 days. The experimental group (mean age 19.5 ± 1.66 years) was bonded with passive self-ligating brackets while the control group (mean age 19.9 ± 1.13 years) was bonded with conventional brackets. Both groups were examined and compared for rate of space closure. An evaluation was conducted for both groups until the entire extraction space was closed and confirmed by evaluation of a tight contact between the canine and the second premolar using a piece of dental floss. RESULTS: Before the initiation of retraction, all initial criteria were similar between the two groups (P > .05). No difference was observed between the two groups in the rate of space closure (P > .05). CONCLUSIONS: MOP in conjunction with passive self-ligation does not increase the rate of orthodontic space closure when compared with MOP used with conventional brackets.


Assuntos
Braquetes Ortodônticos , Fechamento de Espaço Ortodôntico , Adolescente , Adulto , Dente Pré-Molar/cirurgia , Feminino , Humanos , Masculino , Desenho de Aparelho Ortodôntico , Aparelhos Ortodônticos Fixos , Fios Ortodônticos , Técnicas de Movimentação Dentária , Adulto Jovem
13.
Angle Orthod ; 90(5): 688-694, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-33378485

RESUMO

OBJECTIVE: To compare the biomechanics of straight labial, straight lingual, and mushroom lingual archwire systems when used in posterior arch expansion. MATERIALS AND METHODS: An electro-mechanical orthodontic simulator allowing for buccal-lingual and vertical displacements of individual teeth and three-dimensional force/moment measurements was instrumented with anatomically shaped teeth for the maxillary arch. In-Ovation L brackets were bonded to lingual surfaces, and Carriere SLX brackets were bonded to labial surfaces to ensure consistency of slot dimensions. Titanium molybdenum archwires were bent to an ideal arch form, and the teeth on the orthodontic simulator were set to a passive position. Posterior teeth from the canine to second molar were moved lingually to replicate a constricted arch. From the constricted position, the posterior teeth were simultaneously moved until the expansive force decreased below 0.2 N. Initial force/moment systems and the amount of predicted expansion were compared for posterior teeth at a significance level of α = 0.05. RESULTS: Archwire type affected both the expected expansion and initial force/moment systems produced in the constricted position. In general, the lingual systems produced the most expansion. The archwire systems were not able to return the teeth to their ideal position, with the closest system reaching 41% of the intended expansion. CONCLUSIONS: In general, lingual systems were able to produce greater expansion in the posterior regions when compared with labial systems. However, less than half of the intended arch expansion was achieved with all systems tested.


Assuntos
Braquetes Ortodônticos , Fios Ortodônticos , Fenômenos Biomecânicos , Incisivo , Desenho de Aparelho Ortodôntico , Técnicas de Movimentação Dentária
14.
Angle Orthod ; 90(6): 801-810, 2020 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-33378514

RESUMO

OBJECTIVES: To assess the mechanical environment for three fixed appliances designed to retract the lower anterior segment. MATERIALS AND METHODS: A cone-beam computed tomography scan provided three-dimensional morphology to construct finite element models for three common methods of lower anterior retraction into first premolar extraction spaces: (1) canine retraction with a T-loop, (2) en-masse space closure with the power-arm on the canine bracket (PAB), and (3) power-arm directly attached to the archwire mesial to the canine (PAW). Half of the symmetric mandibular arch was modeled as a linear, isotropic composite material containing five teeth: central incisors (L1), lateral incisor (L2), canine (L3), second premolar (L4), and first molar (L5). Bonded brackets had 0.022-in slots. Archwire and power-arm components were 0.016 × 0.022 in. An initial retraction force of 125 cN was used for all three appliances. Displacements were calculated. Periodontal ligament (PDL) stresses and distributions were calculated for four invariants: maximum principal, minimum principal, von Mises, and dilatational stresses. RESULTS: The PDL stress distributions for the four invariants corresponded to the displacement patterns for each appliance. T-loop tipped the canine(s) and incisors distally. PAB rotated L3 distal in, intruded L2, and extruded L1. PAW distorted the archwire resulting in L3 extrusion as well as lingual tipping of L1 and L2. Maximum stress levels in the PDL were up to 5× greater for the PAW than the T-loop and PAB methods. CONCLUSIONS: T-loop of this type is more predictable because power-arms can have rotational and archwire distortion effects that result in undesirable paths of tooth movement.


Assuntos
Incisivo , Técnicas de Movimentação Dentária , Dente Pré-Molar , Fenômenos Biomecânicos , Dente Canino/diagnóstico por imagem , Análise de Elementos Finitos , Fios Ortodônticos , Estresse Mecânico
15.
Orthod Fr ; 91(4): 303-321, 2020 Dec 01.
Artigo em Francês | MEDLINE | ID: mdl-33355535

RESUMO

The aim of this systematic review and meta-analysis was to compare self-ligating brackets (SLBs) considered as a whole to conventional brackets (CBs). An electronic search was performed in three databases (PubMed, MEDLINE via Web of Science, Cochrane Library) from their origin up to June 2017. Additional articles were hand searched from January 2006 to June 2017. This meta-analysis was restricted to randomized controlled trials (RCTs) and split mouth design studies (SMDs). No distinction was made between active and passive SLBs. The following variables were investigated : treatment duration, number of visits, alignment rate, rate of space closure, perception of discomfort during the initial phase of treatment, pain experience during wire insertion or removal, bond failure rate, time to ligate in or to untie an archwire, periodontal indices, occlusal outcomes, transverse arch dimensional changes and root resorption. 25 RCTs and 9 SMDs were finally selected. It was more painful to insert or remove a 0.019× 0.025 SS archwire in/from SLBs. It was significantly quicker to insert or remove an archwire from SLBs. There was less bleeding on probing with SLBs 4 or 5 weeks after bonding. All other variables did not exhibit any significant difference between SLBs and CBs. Out of the 31 comparisons between self-ligating and conventional brackets, 9 only revealed statistically significant differences. This meta-analysis contradicts most of the promotional statements put forward by the distributors.


Assuntos
Braquetes Ortodônticos , Reabsorção da Raiz , Face , Humanos , Boca , Desenho de Aparelho Ortodôntico , Fios Ortodônticos
16.
J Clin Pediatr Dent ; 44(6): 451-458, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33378466

RESUMO

OBJECTIVE: The surface roughness of various orthodontic materials could affect biofilm formation and friction. The purpose of this study was to examine the surface roughness and chemical composition of the slots and wings of several ceramic self-ligating brackets. STUDY DESIGN: Four types of ceramic self-ligating brackets were separated into experimental groups (DC, EC, IC, and QK) while a metal self-ligating bracket (EM) was used as the control group. Atomic force microscopy and energy-dispersive x-ray spectroscope were used to examine the surface roughness and chemical composition of each bracket slot and wing. RESULTS: The control group was made of ferrum and chrome while all the experimental groups were comprised of aluminum and oxide. There was a statistically significant difference in the roughness average (Sa) among the various self-ligating brackets (p< 0.001 in slots and p<0.01 in the wing). The slots in the EC group had the lowest Sa, followed by the DC, IC, control, and QK groups. The wings in the IC group had the lowest Sa, followed by the EC, DC, control, and QK groups. CONCLUSIONS: There is a significant difference in the surface roughness of the slots and wings among several types of ceramic self-ligating brackets.


Assuntos
Braquetes Ortodônticos , Biofilmes , Cerâmica , Ligas Dentárias , Fricção , Humanos , Teste de Materiais , Desenho de Aparelho Ortodôntico , Fios Ortodônticos , Aço Inoxidável , Propriedades de Superfície
17.
Head Face Med ; 16(1): 32, 2020 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-33243257

RESUMO

BACKGROUND: The Multiloop Edgewise Archwire (MEAW) appliance is an orthodontic treatment method suitable for the therapy of severe types of malocclusions such as open bites or anterior crossbites. The cephalometric Denture Frame Analysis (DFA) provides a supportive diagnostic tool for patient-specific treatment planning concerning the rearrangement of occlusion within the "denture frame". The objective of this study is to give a comprehensive overview of the national and international scientific literature about MEAW and DFA regarding the general therapeutic effects, advantages and limitations. METHODS AND MATERIALS: A computerized literature search was performed using four principal medical databases (PubMed/Medline, Google Scholar, Web of Science and Cochrane Central Register of Controlled Trials) and supplemented by manual searching of the references listed in the retrieved articles. The results were screened and assessed following the PRISMA guidelines. RESULTS: Six hundred seventy-seven full articles were assessed for eligibility. A number of 134 articles went through qualitative analysis and 3 studies were finally involved in comparative synopsis. The findings reveal advantageous characteristics of the MEAW technique such as a high degree of three-dimensional individual tooth control and a comparatively low load deflection rate, causing mostly dentoalveolar changes without significantly influencing the skeletal structures. CONCLUSION: Based on current literature, the MEAW technique appears to have several therapeutic benefits and serves as a sufficient alternative treatment method for dentoalveolar compensation, when measures of orthognathic surgery are rejected. Concerning the deficient data basis of available literature and the low level of scientific evidence, further studies are required in order to expand on the knowledge in this subject area. Several aspects like the effectiveness or the long-term stability have to be evaluated more extensively. Moreover, the transferability of the DFA to ethnic groups other than the Asian ethnicity should be examined further.


Assuntos
Má Oclusão , Fios Ortodônticos , Cefalometria , Dentaduras , Humanos , Má Oclusão/terapia , Técnicas de Movimentação Dentária
18.
Orthod Fr ; 91(3): 249-262, 2020 10 01.
Artigo em Francês | MEDLINE | ID: mdl-33146619

RESUMO

The use of self-ligating brackets has largely developed in orthodontic practice thanks to numerous advantages, including the reduction of frictional forces during sliding orthodontic mechanic. Faced with scientific evidence, this advantage still seems to be debatable. Our objective was to evaluate in vivo the frictional force of self-ligating brackets by searching for micro-morphological and chemical effects on the active slot surface, after phase of alignment-leveling and after a period in the mouth. 16 brackets from four commercial brands were selected (Damon®, In-Ovation®, Smart-clip® and Carriere®). These brackets were visualized using a scanning electron microscope (SEM) and dispersive energy spectroscopy to study their surface and initial chemical composition. After a period in the mouth, these brackets were debonded and evaluated with SEM, to search topographic and chemical changes in relation to the frictional forces. After a period of three months used for dental alignment, all the brackets show considerable changes in topographic and chemical properties related to frictional forces, with deposit of organic debris whose importance is related to the initial surface different from one manufacturer to another.


Assuntos
Braquetes Ortodônticos , Fios Ortodônticos , Ligas Dentárias , Análise do Estresse Dentário , Fricção , Teste de Materiais , Desenho de Aparelho Ortodôntico , Aço Inoxidável , Propriedades de Superfície
19.
Dental Press J Orthod ; 25(4): 51-58, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32965387

RESUMO

OBJECTIVE: To investigate the effect of ZnO nanocoating on mechanical properties of NiTi orthodontic wires and antibacterial activity. METHODS: 0.016 x 0.022-in NiTi orthodontic wires were coated with ZnO nanoparticles using an electrochemical deposition method with three electrodes system in 0.1M Zn(NO3)2. Mechanical properties and frictional resistance of the coated wires were investigated using an universal testing machine. Antibacterial effect of ZnO coating was also investigated. RESULTS: A stable adhered ZnO nanocoating on NiTi wires was obtained. The coated wires have a significant antibacterial activity against S. aureus, S. pyogens and E. coli, and a reduction of frictional forces by 34%. CONCLUSION: ZnO nanocoating may improve the antibacterial effects of NiTi wires and reduce the frictional resistance. Coating may be implanted in orthodontic practice for faster and safer treatment.


Assuntos
Óxido de Zinco/farmacologia , Antibacterianos/farmacologia , Ligas Dentárias , Escherichia coli , Teste de Materiais , Níquel , Fios Ortodônticos , Staphylococcus aureus , Propriedades de Superfície , Titânio/farmacologia , Zinco
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