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The Angle Orthodontist Sep 2017To biomechanically test a new elastic slot system and V-wire mechanics.
OBJECTIVE
To biomechanically test a new elastic slot system and V-wire mechanics.
MATERIALS AND METHODS
Conventional twin and self-ligating brackets and the new elastodynamic bracket were biomechanically tested. The conventional brackets had a rectangular 0.022'' slot and the new elastodynamic bracket had a V-slot, a new slot geometry. Torque measurements were performed with 0.018'' × 0.025'' and 0.019'' × 0.025'' stainless steel (ss) archwires. A nickel-titanium V wire was used for the biomechanical measurements on the elastodynamic bracket. The measurements were done with the aid of a six-component measuring sensor.
RESULTS
The results of the biomechanical testing revealed play in the brackets with rectangular slot geometry. The V slot in the elastodynamic bracket assured that the wire fit perfectly in the slot. Dynamic moments of 5 to 10 Nmm were transmitted without any play. No permanent deformation of the slot occurred in the new elastodynamic bracket because of the elastic slot.
CONCLUSION
Control of torque for three-dimensional positioning of the teeth in the dental arch with rectangular slot geometry as used in straight-wire therapy is difficult. If torque is bent into the wire, because of the play there is a high risk that either too much, too little, or no moment is transmitted to the teeth. The V-slot archwire/bracket geometry in conjunction with nickel titanium composition has no play and allows a reduction of forces and moments with direct and continuous transmission of torque in the bracket. Because of the elasticity of the bracket, there is an upper limit to the moment possible.
Topics: Biomechanical Phenomena; Dental Alloys; Dental Stress Analysis; Elasticity; Humans; Materials Testing; Nickel; Orthodontic Appliance Design; Orthodontic Brackets; Orthodontic Wires; Rotation; Stainless Steel; Stress, Mechanical; Surface Properties; Titanium; Torque
PubMed: 28530449
DOI: 10.2319/121516-899 -
The Angle Orthodontist May 2016To elicit the magnitude, directional bias, and frequency of bracket positioning errors caused by the transfer of brackets from a dental cast to the patient's dentition...
OBJECTIVE
To elicit the magnitude, directional bias, and frequency of bracket positioning errors caused by the transfer of brackets from a dental cast to the patient's dentition in a clinical setting.
MATERIALS AND METHODS
A total of 136 brackets were evaluated. The brackets were placed on dental casts and scanned using cone beam computed tomography (CBCT) to capture 3-D positioning data. The brackets were then transferred to the patient's dentition with an indirect bonding method using vinyl polysiloxane (VPS) trays and later scanned using CBCT to capture the final bracket positioning on the teeth. Virtual models were constructed from the two sets of scan data and digitally superimposed utilizing best-fit, surface-based registration. Individual bracket positioning differences were quantified using customized software. One-tailed t tests were used to determine whether bracket positioning was within limits of 0.5 mm in the mesiodistal, buccolingual, and vertical dimensions, and 2° for torque, tip, and rotation.
RESULTS
Individual bracket positioning differences were not statistically significant, indicating, in general, final bracket positions within the selected limits. Transfer accuracy was lowest for torque (80.15%) and highest for mesiodistal and buccolingual bracket placement (both 98.53%). There was a modest directional bias toward the buccal and gingival.
CONCLUSION
Indirect bonding using VPS trays transfers the planned bracket position from the dental cast to the patient's dentition with generally high positional accuracy.
Topics: Dental Bonding; Humans; Models, Dental; Orthodontic Brackets; Polyvinyls; Siloxanes
PubMed: 26355994
DOI: 10.2319/042415-279.1 -
Dental Materials Journal Sep 2021The purpose of this study was to determine whether a system using a resin coating material (PRG Barrier Coat) with anticariogenic ability can effectively bond...
The purpose of this study was to determine whether a system using a resin coating material (PRG Barrier Coat) with anticariogenic ability can effectively bond orthodontic brackets to human teeth. Resin-modified glass-ionomer cement system (Fuji Ortho LC, group 1) and resin composite cement systems (BeautyOrtho Bond) combined with a self-etching primer (group 2), with the resin coating material (group 3), and with the resin coating material after an organic acid etching agent (group 4) were used for bracket bonding. The mean shear bond strength (SBS) was significantly higher in group 1 than in groups 2, 3 and 4. Groups 2 and 4 exhibited a significantly higher mean SBS than group 3. The resin composite cement system combined with the resin coating material after the organic acid etching agent can serve as an alternative for orthodontic bracket bonding.
Topics: Acid Etching, Dental; Dental Bonding; Humans; Materials Testing; Orthodontic Brackets; Shear Strength
PubMed: 34193724
DOI: 10.4012/dmj.2020-249 -
Progress in Orthodontics Sep 2022When the indirect bonding technique was developed in 1972 by Silverman and Cohen, many authors wondered whether this technique would improve bracket positioning accuracy...
BACKGROUND/OBJECTIVES
When the indirect bonding technique was developed in 1972 by Silverman and Cohen, many authors wondered whether this technique would improve bracket positioning accuracy compared to the direct bonding technique. Studies have found little to no difference between them regarding positioning accuracy. Recently, technological advances have improved the indirect method by allowing the user to position the brackets virtually using software applications such as OrthoAnalyzer™. To the best of our knowledge, no studies have compared direct positioning to this new digital indirect technique. Thus, the aim of this study was to compare the accuracy of placement between the two techniques in the maxillary arch using two different bracket types: conventional twin brackets and self-ligating brackets. A secondary objective was to evaluate whether bracket type affected positioning accuracy.
METHODS
A maxillary arch of a patient was scanned by digital impression. Forty resin duplicates of this model were printed and then mounted on a mannequin head, on which 20 practitioners performed direct bonding using the aforementioned brackets. Later on, they performed a virtual indirect bonding of the same case virtually, with the digital impression superimposed to the patient's CBCT (cone-beam computed tomography). Afterwards, the direct bonded models were unmounted, scanned, and then superimposed to the indirect models. Differences in height, angulation and mesio-distal position of the brackets were evaluated.
RESULTS
Regarding height, the differences between direct and indirect methods were not significant. Height difference was significantly greater for self-ligating brackets compared to conventional brackets. Regarding mesio-distal positioning, significant differences were noted for teeth 13 and 15 with self-ligating brackets (p-value = 0.019 and p-value = 0.043, respectively). The deviation was also greater for these brackets. Regarding angulation, the difference was significant on tooth 12 when using conventional brackets (p-value = 0.04) and on 12 and 22 when using self-ligating brackets (p-value = 0.09).
CONCLUSION/IMPLICATIONS
There were no major significant differences between direct and indirect bonding. Differences were significant only on the laterals for of angulation, and on teeth 13 and 15 for mesio-distal centering. The bracket type seems to influence positioning accuracy, since self-ligating brackets had a larger deviation range than conventional brackets.
Topics: Bicuspid; Dental Bonding; Humans; Maxilla; Models, Dental; Orthodontic Brackets
PubMed: 36058991
DOI: 10.1186/s40510-022-00426-3 -
The Angle Orthodontist Jan 2021The need for intraoral scanning in the presence of brackets has increased for monitoring tooth movement during orthodontic treatment. The purpose of this study was to...
OBJECTIVES
The need for intraoral scanning in the presence of brackets has increased for monitoring tooth movement during orthodontic treatment. The purpose of this study was to evaluate the effect of orthodontic brackets bonded to tooth surfaces on intraoral scans.
MATERIALS AND METHODS
Intraoral scans were performed in 30 patients using both iTero and Trios scanners before and after bonding of the brackets. The two sets of intraoral scans of each patient and intraoral scans with and without brackets were superimposed using a best-fit algorithm, and three-dimensional (3D) surface analysis was performed. In each superimposition, discrepancies in the 3D axes and arch-width measurements in the incisor and molar regions were compared. In addition, the range of distortion around the brackets was evaluated on the cross sections of each superimposition.
RESULTS
The overall discrepancies between the intraoral scans with and without brackets were within 0.30 mm. The arch-width discrepancies in the molar region were greater than those in the incisor region, but the differences were not statistically significant (P = .972 for iTero; P = .960 for Trios). The cross sections of the superimposed intraoral scans with and without brackets showed that the deviations were within 0.40 mm in the horizontal section and within 0.35 mm in the vertical section around the brackets.
CONCLUSIONS
The results of this study indicate that the accuracy of intraoral scans, even in the presence of brackets, is clinically acceptable, and the regions beyond 0.50 mm around the brackets should be used for superimposition on images without brackets.
Topics: Computer-Aided Design; Dental Impression Technique; Humans; Imaging, Three-Dimensional; Models, Dental; Molar; Orthodontic Brackets; Tooth Movement Techniques
PubMed: 33289796
DOI: 10.2319/040420-254.1 -
Materials (Basel, Switzerland) Sep 2020Based on the development of many adhesive systems and bonding techniques, bonding strength of orthodontic brackets has become even more important in modern clinical...
Based on the development of many adhesive systems and bonding techniques, bonding strength of orthodontic brackets has become even more important in modern clinical orthodontics. The aim of this study was to determine mean shearing stroke frequency of different orthodontic bracket types and bonding agents under cycling loading. Therefore, 10 different types of orthodontic bracket from 4 different brands were divided into 2 groups. Two different adhesives, namely Transbond™ XT etch-and-rinse for and Transbond™ Plus self-etching-primer adhesive for were considered. The brackets were tested under cycling loading force of 10-N and a crosshead speed of 300 mm/min and 40 cycle/min. The frequency of strokes that the brackets failed were determined and these data were analyzed by statistical analysis using an independent sample -test and one-way analysis of variance (ANOVA). The level of significance was set at < 0.05. Generally, differences between the frequency of shearing strokes of the bracket failures were found to be statistically significant depending on the type of adhesives and brackets ( < 0.05). The bonding technique for Group 1 was found to have a significantly higher shear bonding strength than Group 2. It is also seen that different types of bracket belonging to the same or different brands had different shear bonding strength. It may be concluded that: (i) all bracket types used in this study can be applied with both bonding techniques, (ii) in order to minimize the risk of hard tissue damage, ceramic brackets should be carefully bonded using the self-etching primary adhesive technique.
PubMed: 32992817
DOI: 10.3390/ma13194280 -
Head & Face Medicine Aug 2020This study aimed at comparing bracket placement and excess bonding adhesive depending on different indirect bonding (IDB) techniques and bracket geometries.
BACKGROUND
This study aimed at comparing bracket placement and excess bonding adhesive depending on different indirect bonding (IDB) techniques and bracket geometries.
METHODS
Four hundred eighty brackets without hook (WOH) and 360 with hook (WH) were placed on 60 plaster models. Three IDB techniques were tested: polyvinyl-siloxane vacuum-form (PVS-VF), polyvinyl-siloxane putty (PVS-putty), and translucence double-polyvinyl-siloxane (double-PVS). PVS-VF and PVS-putty were combined with chemically, and double-PVS was combined with light cured bonding adhesive. Virtual images of models before and after bracket transfer were generated, and computerized images were compared. Linear, angular deviations, and excess bonding adhesive were measured.
RESULTS
Linear differences between the three groups were obtained for PVS-VF (WH: 1.08, SD 0.50 mm; WOH: 0.86, SD 0.25 mm), PVS-putty (WH: 0.73, SD 0.51 mm; WOH: 0.58, SD 0.28 mm), and double-PVS (WH: 0.65, SD 0.45 mm; WOH: 0.59, SD 0.33 mm) (P < 0.001). Hooks affected bracket placement accuracy in PVS-VF (P < 0.001) and PVS-putty (P = 0.029). Angular differences were observed for brackets WOH between the PVS-VF (0.64, SD 0.48°) and double-PVS group (0.92, SD 0.76°) (P < 0.001) and within double-PVS group (WH: 0.66, SD 0.51° vs. WOH: 0.92, SD 0.76°, P < 0.001). Highest amount of excess adhesive was obtained for PVS-putty group (WH: 6.54, SD 5.31 mm ).
CONCLUSIONS
The double-PVS group revealed promising results with respect to transfer accuracy, whereas the PVS-VF group provided least excess bonding adhesive. Basically, hooks lead to lower precision and higher excess bonding adhesive. PVS trays for IDB generate high bracket placement accuracy. PVS-putty is the easiest to handle with and also the cheapest, but leads to large excess bonding adhesive, especially in combination with hooked brackets or tubes.
Topics: Dental Bonding; Dental Cements; Orthodontic Brackets
PubMed: 32741369
DOI: 10.1186/s13005-020-00231-5 -
Dental Press Journal of Orthodontics 2016The objective of this present study was to understand how children and adolescents perceive esthetic attractiveness of a variety of orthodontic appliances. It also...
OBJECTIVE:
The objective of this present study was to understand how children and adolescents perceive esthetic attractiveness of a variety of orthodontic appliances. It also analyzed preferences according to patients' age, sex and socioeconomic status.
METHODS:
A photograph album consisting of eight photographs of different orthodontic appliances and clear tray aligners placed in a consenting adult with pleasing smile was used. A sample of children or adolescents aged between 8 and 17 years old (n = 276) was asked to rate each image for its attractiveness on a visual analog scale. Comparisons between the appliances attractiveness were performed by means of nonparametric statistics with Friedman's test followed by Dunn's multiple comparison post-hoc test. Correlation between appliances and individuals' socioeconomic status, age, sex, and esthetic perception was assessed by means of Spearman's correlation analysis.
RESULTS:
Attractiveness ratings of orthodontic appliances varied nonsignificantly for children in the following hierarchy: traditional metallic brackets with green elastomeric ligatures > traditional metallic brackets with gray elastomeric ligatures > sapphire esthetic brackets; and for adolescents, as follows: sapphire esthetic brackets > clear aligner without attachments > traditional metallic brackets with green elastomeric ligatures. The correlation between individuals' socioeconomic status and esthetic perception of a given appliance was negative and statistically significant for appliances such as the golden orthodontic brackets and traditional metallic brackets with green elastomeric ligatures.
CONCLUSION:
Metal appliances were considered very attractive, whereas aligners were classified as less attractive by children and adolescents. The correlation between esthetic perception and socioeconomic status revealed that individuals with a higher socioeconomic level judged esthetics as the most attractive attribute. For those with higher economic status, golden orthodontic brackets and traditional metallic brackets with green elastomeric ligatures were assessed as the worst esthetic option.
Topics: Adolescent; Brazil; Child; Color; Esthetics; Esthetics, Dental; Female; Humans; Male; Orthodontic Appliance Design; Orthodontic Brackets; Social Class
PubMed: 27901230
DOI: 10.1590/2177-6709.21.5.058-066.oar -
European Journal of Orthodontics Jan 2020Although ceramic brackets have been extensively used for decades in orthodontics there is not till today any study focusing on the possible deterioration of mechanical...
BACKGROUND
Although ceramic brackets have been extensively used for decades in orthodontics there is not till today any study focusing on the possible deterioration of mechanical properties after in vivo ageing.
OBJECTIVES
To determine whether the mechanical properties of alumina orthodontic brackets change after intraoral ageing thereby assessing the validity of a theoretical model established for the performance of ceramics in wet environments.
MATERIALS AND METHODS
Two alumina brackets, one single crystal (Radiance, American Orthodontics, Sheboygan, WI) and one polycrystalline (Clarity, 3M, St. Paul, MN) were included in this study. Ten brackets for each group were collected from different patients after a minimum of 3-month intraoral exposure, whereas as-received brackets of the same manufacturers were used as controls. The specimens were subjected to Raman spectroscopy and were then embedded in epoxy resin and metallographic ground and polished. The mechanical properties of four groups (radiance control: RAC, radiance-retrieved RAR, clarity control: CLC and clarity-retrieved CLR) were determined using instrumented indentation testing according to ISO 14577-2002. The mechanical properties tested were Martens hardness (HM), indentation modulus (EIT), the ratio of elastic to total work, commonly known as elastic index (ηIT), and fracture toughness (KIC). The numerical results were statistically analysed employing two-way analysis of variance (ANOVA) and Tukey multiple comparison test at a = 0.05.
RESULTS
Raman analysis revealed that both brackets are made of a-Al2O3 (corundum). No statistically significant differences were found for HM (N/mm2): RAC = 7249 (1507), RAR = 6926 (1144), CLC = 8052 (1360), CLR = 7390 (2393), or for EIT (GPa): RAC = 141 (27), RAR = 139 (23), CLC = 139 (28), CLR = 131 (47). However, significant differences were identified between the two alumina brackets tested for ηIT (%): RAC = 55.7 (4.2), RAR = 54.0 (3.5), CLC = 62.5 (4.4), CLR = 61.8 (4.7), while KIC was measured only for the polycrystalline bracket (Clarity) because of the complicated fractured pattern of the single-crystal bracket. Both brackets share equal HM and EIT before and after orthodontic intraoral ageing.
LIMITATIONS
Whereas the study assessed the changes after intraoral exposure per theoretical model, which describes the reduction of critical stress to induce fracture after wetting, long-term intraoral ageing could have induced more pronounced effects.
CONCLUSIONS/IMPLICATIONS
The results of this study indicate that 3 months of intraoral ageing do not change the mechanical properties of single-crystal and polycrystalline orthodontic brackets tested, thus indicating that the Griffith theory may not be applied to the case of manufactured ceramic brackets owing possibly to internal defects.
Topics: Ceramics; Hardness; Humans; Materials Testing; Orthodontic Brackets; Stress, Mechanical; Surface Properties; Time Factors
PubMed: 31009950
DOI: 10.1093/ejo/cjz024 -
International Journal of Oral Science Mar 2017White spot lesions (WSLs), due to enamel demineralization, occur frequently in orthodontic treatment. We recently developed a novel rechargeable dental composite...
White spot lesions (WSLs), due to enamel demineralization, occur frequently in orthodontic treatment. We recently developed a novel rechargeable dental composite containing nanoparticles of amorphous calcium phosphate (NACP) with long-term calcium (Ca) and phosphate (P) ion release and caries-inhibiting capability. The objectives of this study were to develop the first NACP-rechargeable orthodontic cement and investigate the effects of recharge duration and frequency on the efficacy of ion re-release. The rechargeable cement consisted of pyromellitic glycerol dimethacrylate (PMGDM) and ethoxylated bisphenol A dimethacrylate (EBPADMA). NACP was mixed into the resin at 40% by mass. Specimens were tested for orthodontic bracket shear bond strength (SBS) to enamel, Ca and P ion initial release, recharge and re-release. The new orthodontic cement exhibited an SBS similar to commercial orthodontic cement without CaP release (P>0.1). Specimens after one recharge treatment (e.g., 1 min immersion in recharge solution repeating three times in one day, referred to as "1 min 3 times") exhibited a substantial and continuous re-release of Ca and P ions for 14 days without further recharge. The ion re-release did not decrease with increasing the number of recharge/re-release cycles (P>0.1). The ion re-release concentrations at 14 days versus various recharge treatments were as follows: 1 min 3 times>3 min 2 times>1 min 2 times>6 min 1 time>3 min 1 time>1 min 1 time. In conclusion, although previous studies have shown that NACP nanocomposite remineralized tooth lesions and inhibited caries, the present study developed the first orthodontic cement with Ca and P ion recharge and long-term release capability. This NACP-rechargeable orthodontic cement is a promising therapy to inhibit enamel demineralization and WSLs around orthodontic brackets.
Topics: Benzoates; Bisphenol A-Glycidyl Methacrylate; Calcium Phosphates; Dental Cements; Humans; In Vitro Techniques; Materials Testing; Methacrylates; Nanoparticles; Orthodontic Brackets; Shear Strength; Tooth Remineralization
PubMed: 27811847
DOI: 10.1038/ijos.2016.40