Moschos A. Papadopoulos

Failure rates and associated risk factors of orthodontic miniscrew implants: a meta-analysis.

INTRODUCTION Risk factors concerning orthodontic miniscrew implants have not been adequately assessed. In this systematic review, we summarize the knowledge from published clinical trials regarding the failure rates of miniscrew implants used for orthodontic anchorage purposes and identify the factors that possibly affect them. METHODS Nineteen electronic databases and reference lists of included studies were searched up to February 2011, with no restrictions. Only randomized controlled trials, prospective controlled trials, and prospective cohort studies were included. Study selection and data extraction were performed twice. Failure event rates, relative risks, and the corresponding 95% confidence intervals were calculated. The random-effects model was used to assess each factors impact. Subgroup and meta-regression analyses were also implemented. RESULTS Fifty-two studies were included for the overall miniscrew implant failure rate and 30 studies for the investigation of risk factors. From the 4987 miniscrew implants used in 2281 patients, the overall failure rate was 13.5% (95% confidence interval, 11.5-15.8). Failures of miniscrew implants were not associated with patient sex or age and miniscrew implant insertion side, whereas they were significantly associated with jaw of insertion. Certain trends were identified through exploratory analysis; however, because of the small number of original studies, no definite conclusions could be drawn. CONCLUSIONS Orthodontic miniscrew implants have a modest small mean failure rate, indicating their usefulness in clinical practice. Although many factors seem to affect their failure rates, the majority of them still need additional evidence to support any possible associations.

Clinical Effectiveness of Orthodontic Miniscrew Implants: a Meta-analysis

The aim of this meta-analysis was to examine the clinical effectiveness of miniscrew implants (MI) used for anchorage reinforcement compared with that of conventional orthodontic means, as well as to assess the success rates of MIs and the possible risk factors affecting their clinical effectiveness. Literature searches were conducted, and, using specific inclusion and exclusion criteria, two independent investigators performed data extraction and analysis. Overall pooled estimates with 95% confidence intervals (CI) were obtained with the random-effects model. Eight out of 3183 original papers met the inclusion criteria. The mean difference of anchorage loss between the MI and conventional anchorage group was −2.4 mm (95% CI = −2.9 mm to −1.8 mm, p = 0). MIs significantly decreased or negated loss of anchorage. Anchorage loss seemed to be less in the mandible, when the MIs were inserted between the second premolar and the first molar, when 2 MIs were inserted per patient jaw, when they were directly connected, as well as when treatment lasted more than 12 months. MIs presented a success rate of 87.7%, with no significant differences between the various subgroups. However, the results of this meta-analysis should be interpreted with some caution because of the number, quality, and heterogeneity of the included studies.

Clinical characteristics and properties of ceramic brackets: A comprehensive review

The aim of this article is to provide the clinician with an up-to-date comprehensive literature review concerning the clinical characteristics and properties of ceramic brackets. The article critically presents and discusses the various aspects of ceramic brackets with regard to the types, physical properties, bond strength, frictional resistance, base surface characteristics, debonding techniques and enamel fracture risks, enamel abrasion and wear, bracket fracture, and bracket recycling. The article contains also guidelines and criteria concerning the specific applications and use of ceramic brackets.

Accuracy and precision of the three-dimensional assessment of the facial surface using a 3-D laser scanner

Three-dimensional (3-D) recording of the surface of the human body or anatomical areas has gained importance in many medical specialties. Thus, it is important to determine scanner precision and accuracy in defined medical applications and to establish standards for the recording procedure. Here we evaluated the precision and accuracy of 3-D assessment of the facial area with the Minolta Vivid 910 3D Laser Scanner. We also investigated the influence of factors related to the recording procedure and the processing of scanner data on final results. These factors include lighting, alignment of scanner and object, the examiner, and the software used to convert measurements into virtual images. To assess scanner accuracy, we compared scanner data to those obtained by manual measurements on a dummy. Less than 7% of all results with the scanner method were outside a range of error of 2 mm when compared to corresponding reference measurements. Accuracy, thus, proved to be good enough to satisfy requirements for numerous clinical applications. Moreover, the experiments completed with the dummy yielded valuable information for optimizing recording parameters for best results. Thus, under defined conditions, precision and accuracy of surface models of the human face recorded with the Minolta Vivid 910 3D Scanner presumably can also be enhanced. Future studies will involve verification of our findings using test persons. The current findings indicate that the Minolta Vivid 910 3D Scanner might be used with benefit in medicine when recording the 3-D surface structures of the face

Evaluation of methodology and quality characteristics of systematic reviews in orthodontics

Systematic reviews (SRs) are published with an increasing rate in many fields of biomedical literature, including orthodontics. Although SRs should consolidate the evidence-based characteristics of contemporary orthodontic practice, doubts on the validity of their conclusions have been frequently expressed. The aim of this study was to evaluate the methodology and quality characteristics of orthodontic SRs as well as to assess their quality of reporting during the last years. Electronic databases were searched for SRs (without any meta-analytical data synthesis) in the field of orthodontics, indexed up to the start of 2010. The Assessment of Multiple Systematic Reviews (AMSTAR) tool was used for quality assessment of the included articles. Data were analyzed with Students t-test, one-way ANOVA, and linear regression. Risk ratios (RR) with 95% confidence intervals were calculated to represent changes during the years in reporting of key items associated with quality. A total of 110 SRs were included in this evaluation. About half of the SRs (46.4%) were published in orthodontic journals, while few (5.5%) were updates of previously published reviews. Using the AMSTAR tool, thirty (27.3%) of the SRs were found to be of low quality, 63 (57.3%) of medium quality, and 17 (15.5%) of high quality. No significant trend for quality improvement was observed during the last years. The overall quality of orthodontic SRs may be considered as medium. Although the number of orthodontic SRs has increased over the last decade, their quality characteristics can be characterized as moderate.

Characterization of retrieved orthodontic miniscrew implants.

INTRODUCTION The purposes of this study were to characterize the morphologic, structural, and compositional alterations and to assess any hardness changes in used orthodontic miniscrew implants. METHODS Eleven miniscrew implants (Aarhus Anchorage System, Medicon eG, Tuttlingen, Germany) placed in 5 patients were retrieved after successful service of 3.5 to 17.5 months; none showed signs of mobility or failure. These implants, and brand-, type-, and size-matched specimens as controls, were subjected to multi-technique characterization. RESULTS Optical microscopy indicated loss of gloss with variable discoloration. Scanning electron microscopy and x-ray microanalysis showed morphologic alteration of the miniscrew implant surfaces with integuments formed on the surface. The materials precipitated on the surfaces were sodium, potassium, chlorine, iron, calcium, and phosphorus from the contact of the implant with biologic fluids such as blood and exudates, forming sodium chloride, potassium chloride, and calcium-phosphorus precipitates. The composition of the implant was similar to that of a titanium alloy. X-ray microtomography analysis showed no bulk structure alterations. Vickers microhardness testing showed no increased bulk or surface hardness of the retrieved specimens compared with the controls, excluding the possibility of strain-hardening phenomena as a result of self-tapping and self-drilling placement and related loading conditions. CONCLUSIONS Used titanium-alloy miniscrew implants have morphologic and surface structural alterations including adsorption of an integument that is calcified as a result of contact of the implants with biologic fluids. Randomly organized osseointegration islets on these smooth titanium-alloy miniscrew surfaces might be enhanced by the extended period of retention in alveolar bone in spite of the smooth surface and immediate loading pattern of these implants.

Efficiency of noncompliance simultaneous first and second upper molar distalization: a three-dimensional tooth movement analysis.

Objective of this prospective study was the three-dimensional (3D) analysis of tooth movements after the noncompliance simultaneous distalization of the first and second maxillary molars. Ten patients (five girls and five boys; mean age: 13.2 years) with bilateral Class II molar relationships were treated with a noncompliance, fixed intraoral appliance. Upper second molars had already erupted in all cases. Dental casts and lateral cephalometric radiographs were taken immediately before placement and after removal of the appliance. The casts were 3D digitized and superimposed on a predefined area in the palate. The resulting holograms, as well as the cephalometric radiographs, were digitized and analyzed by means of customized cephalometric software. The whole procedure was repeated after a two- to four-week interval to estimate the error of both methods. The cast assessment of 3D sagittal and vertical tooth movements was more reliable than the cephalometric record. The average maxillary first molar distal movement was 2.8 mm. Anchorage loss was expressed by a 1.9-mm proclination of the central incisors. A substantial variation among patients and among the right and left side in the same patient was observed. Noncompliance simultaneous distalization of the first and second maxillary molars can be an efficient treatment option for the correction of Class II molar relationship. However, anchorage loss and individual variation have to be seriously considered. Bilaterally symmetrical effectiveness should not be relied upon.

Treatment effects of removable functional appliances in patients with Class II malocclusion: a systematic review and meta-analysis

OBJECTIVE To assess the treatment effects of fixed functional appliances (FFAs) in treated versus untreated Class II patients by means of lateral cephalometric radiographs. SEARCH METHODS Unrestricted electronic search of 18 databases and additional manual searches up to October 2014. SELECTION CRITERIA Prospective randomized and non-randomized controlled trials reporting on cephalometric angular measurements of Class II patients treated with FFAs and their matched untreated controls. DATA COLLECTION AND ANALYSIS Skeletal, dental, and soft tissue cephalometric data were annualized and stratified according to the time of evaluation in effects. Following risk of bias evaluation, the mean differences (MDs) and 95 % confidence intervals (CIs) were calculated with random-effects models. Patient- and appliance-related subgroup analyses and sensitivity analyses were performed with mixed-effects models. RESULTS Nine studies were included (244 patients; mean age: 13.5 years and 174 untreated controls; mean age: 12.8 years) reporting on cephalometric effects directly after the removal of FFAs. FFAs were found to induce a small reduction of SNA angle (MD = -0.83 degree/year, 95 % CI: -1.17 to -0.48), a small increase of SNB angle (MD = 0.87 degree/year, 95 % CI: 0.30-1.43), and moderate decrease of ANB angle (MD = -1.74 degree/year, 95 % CI: -2.50 to -0.98) compared to untreated Class II patients. FFA treatment resulted in significant dentoalveolar and soft tissue changes. Several patient- or appliance-related factors seem to affect the treatment outcome. Long-term effectiveness of FFAs could not be assessed due to limited evidence. CONCLUSIONS According to existing evidence, FFAs seem to be effective in improving Class II malocclusion in the short term, although their effects seem to be mainly dentoalveolar rather than skeletal.

Orthodontic treatment of Class II malocclusion with miniscrew implants

INTRODUCTION Orthodontic treatment of patients with Class II malocclusion who show poor compliance with conventional treatment modalities such as extraoral headgear, functional orthopedic appliances, or conventional fixed appliances with intermaxillary elastics, can be challenging. Noncompliance approaches can be used, but they often pose anchorage problems. METHODS This article describes the orthodontic treatment of a girl, aged 11.5 years, with a Class II malocclusion, a deep bite, and increased overjet. Initially, an intraoral miniscrew implant supported distalization system (MISDS) was used to distalize the maxillary first molars. Temporary stationary anchorage was provided by 2 miniscrew implants that were placed paramedian in the anterior region of the palate. After distalization, the system was modified slightly by a chair-side procedure and then used to provide the desired stationary anchorage for subsequent anterior tooth retraction in conjunction with conventional full fixed orthodontic appliances. RESULTS After 18 months of treatment, a Class I molar relationship was achieved, and the deep bite, overjet, posterior intercuspation, and facial esthetics were improved. Biomechanical considerations, clinical efficacy, and the advantages and potential complications of MISDS treatment are discussed. CONCLUSIONS This case report illustrates the use of MISDS to distalize the maxillary molars and retract the anterior teeth, providing noncompliance, nonextraction, and efficient approach for the orthodontic treatment of patients with Class II malocclusion, which is initially invisible.

Nickel content of as-received and retrieved NiTi and stainless steel archwires: assessing the nickel release hypothesis.

This study assesses the nickel content of as-received and retrieved stainless steel and NiTi archwires alloys. New and used brand-matched, composition-matched, and cross section-matched archwires were subjected to scanning electron microscopy and energy-dispersive electron probe microanalysis. Elemental analysis was performed on three randomly selected areas, and the nickel content, expressed as ratios of Ni/Ti (in NiTi wires) or Ni/Fe (in stainless steel), was statistically analyzed with a t-test (alpha = .05). No changes were detected with respect to Ni content ratios between as-received and retrieved NiTi or stainless steel wires, suggesting an absence of nickel release. Wear and delamination phenomena on the wire surface and the formation of galvanic couple between the stainless steel wires and bracket brazing materials intraorally may modify the corrosion susceptibility of the wire alloys in clinical conditions.