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Scientific Reports Nov 2023This in vitro study evaluated comprehensively the performances of zirconia brackets with varying yttria proportions in manufacturing advanced orthodontic brackets. Three...
This in vitro study evaluated comprehensively the performances of zirconia brackets with varying yttria proportions in manufacturing advanced orthodontic brackets. Three experimental groups of zirconia brackets were fabricated using yttria-stabilized zirconia (YSZ) materials with different yttria proportions-3 mol% yttria (3Y-YSZ), 4 mol% yttria (4Y-YSZ), and 5 mol% yttria (5Y-YSZ) (Tosoh Ceramic, Japan). A polycrystalline alumina ceramic bracket (3M™ Clarity™ Advanced, MBT 0.022-in. slot) was employed as the control group. Morphological properties, including slot surface structure and dimensions, were examined using scanning electron microscopy and surface profiler analysis. Manufacturing accuracy was assessed with root mean square calculations of trueness and precision. Mechanical properties were tested, encompassing static and kinetic frictional resistance (FR) and fracture strength. Optical stability was evaluated through 20,000 cycles of thermocycling and a 7-day immersion in various coloring agents. Within the limitations of this study, zirconia brackets containing 3 to 5 mol% YSZ presented enhanced reliability in terms of dimensional accuracy and demonstrated favorable optical stability. Notably, owing to its advantageous mechanical properties, the 3Y-YSZ variant showed remarkable potential as an advanced material for fabricating orthodontic brackets.
PubMed: 37990080
DOI: 10.1038/s41598-023-47827-w -
Materials (Basel, Switzerland) Jul 2023The aim of this study was to evaluate the effect of different surface treatments on the shear bond strength (SBS) between metal orthodontic brackets and monolithic...
The aim of this study was to evaluate the effect of different surface treatments on the shear bond strength (SBS) between metal orthodontic brackets and monolithic zirconia surfaces bonded with resin composite. Fifty monolithic zirconia (4Y-TZP) disks were sintered and glazed. Specimens were divided into five groups ( = 10) for different surface treatments: control, nano second fiber laser, sandblasting, grinding and tribochemical coating (CoJet Sand 30-μm). Metal orthodontic brackets were bonded to monolithic zirconia surface by two-component orthodontic adhesive. After 500 cycles of thermocycling, shear bond strength values were measured by a universal testing machine at a cross head speed of 0.5 mm/min. The data was recorded as MPa and statistically analyzed with One-way ANOVA, Levene's LSD tests with Bonferroni corrections. The significance level was α = 0.05. The surface topography of one specimen of each group was evaluated by scanning electron microscopy (SEM). Statistically significant difference was observed among study groups ( = 0.018). The lowest shear bond strength was observed in the control group (3.92 ± 1.9). Tribochemical coating showed the highest bond strength (7.44 ± 2.9), which was statistically different from the control and nano second laser (4.3 ± 1.4) groups but not statistically different from grinding (6.15 ± 3.1) or sandblasting (6.47 ± 3.3). SEM images showed comprehensive results of each surface treatment on monolithic zirconia. All failure modes were recorded as adhesive between the composite resin and monolithic zirconia. Based on the findings of this study, it can be concluded that grinding, sandblasting and tribochemical coating techniques showed clinically acceptable bond strength within the range of 6-8 MPa. These surface treatments can be considered suitable for achieving a durable bond between metal orthodontic brackets and monolithic 4Y-TZP ceramic surfaces.
PubMed: 37512447
DOI: 10.3390/ma16145173 -
Clinical Oral Investigations May 2024White spot lesions are the most common iatrogenic effect observed during orthodontic treatment. This study aimed to compare the surface characteristics and antibacterial... (Comparative Study)
Comparative Study
Evaluation of the surface characteristics and antibacterial properties of Titanium dioxide nanotube and methacryloyloxyethylphosphorylcholine (MPC) coated orthodontic brackets-a comparative invitro study.
OBJECTIVES
White spot lesions are the most common iatrogenic effect observed during orthodontic treatment. This study aimed to compare the surface characteristics and antibacterial action of uncoated and coated orthodontic brackets.
MATERIALS AND METHODS
Sixty commercially available stainless steel brackets were coated with TiO nanotubes and methacryloyloxyethylphosphorylcholine. The sample was divided into Group 1: uncoated orthodontic brackets, Group 2: Stainless steel brackets with TiO nanotubes coating, Group 3: Stainless steel brackets with methacryloyloxyethylphosphorylcholine coating, and Group 4: Stainless steel brackets with TiO nanotubes combined with methacryloyloxyethylphosphorylcholine coating. Surface characterization was assessed using atomic force microscopy and scanning electron microscopy. Streptococcus mutans was selected to test the antibacterial ability of the orthodontic brackets, total bacterial adhesion and bacterial viability were assessed. The brackets were subjected to scanning electron microscopy to detect the presence of biofilm.
RESULTS
The surface roughness was the greatest in Group 1 and least in Group 2 followed by Group 4 and Group 3 coated brackets. The optical density values were highest in Group 1 and lowest in Group 4. Comparison of colony counts revealed high counts in Group 1 and low counts in Group 4. A positive correlation between surface roughness and colony counts was obtained, however, was not statistically significant.
CONCLUSIONS
The coated orthodontic brackets exhibited less surface roughness than the uncoated orthodontic brackets. Group 4 coated orthodontic brackets showed the best antibacterial properties.
CLINICAL RELEVANCE
Coated orthodontic brackets prevent adhesion of streptococcus mutans and reduces plaque accumulation around the brackets thereby preventing formation of white spot lesions during orthodontic treatment.
Topics: Titanium; Orthodontic Brackets; Phosphorylcholine; Surface Properties; Streptococcus mutans; Anti-Bacterial Agents; Microscopy, Electron, Scanning; Nanotubes; Bacterial Adhesion; Microscopy, Atomic Force; Materials Testing; Stainless Steel; Methacrylates; Biofilms; Coated Materials, Biocompatible
PubMed: 38761310
DOI: 10.1007/s00784-024-05655-w -
American Journal of Orthodontics and... Sep 2023The aim was to elucidate the magnitude of alterations in systemic blood counts in healthy patients during the first 14 days after fixed orthodontic appliance placement.
INTRODUCTION
The aim was to elucidate the magnitude of alterations in systemic blood counts in healthy patients during the first 14 days after fixed orthodontic appliance placement.
METHODS
This prospective cohort study consecutively included 35 White Caucasian patients starting orthodontic treatment with fixed appliances. The mean age was 24.48 ± 6.68 years. All patients were physically and periodontally healthy. Blood samples were collected at 3 time points: (1) baseline (exactly before the placement of appliances), (2) 5 days after bonding, and (3) 14 days after baseline. Whole blood and erythrocyte sedimentation rates were analyzed in automated hematology and erythrocyte sedimentation rate analyzer. Serum high-sensitivity C-reactive protein levels were measured by the nephelometric method. Standardized sample handling and patient preparation procedures were adopted to reduce preanalytical variability.
RESULTS
A total of 105 samples were analyzed. All clinical and orthodontic procedures were performed without complications or side effects during the study period. All laboratory procedures were performed per protocol. Significantly lower white blood cell counts were detected 5 days after bracket bonding, compared with baseline (P <0.05). Hemoglobin levels were lower at 14 days than baseline (P <0.05). No other significant shifts or alteration patterns were observed over time.
CONCLUSIONS
Orthodontic fixed appliances led to a limited and transient change in white blood cell counts and hemoglobin levels during the first days after bracket placement. The fluctuation of high-sensitivity C-reactive protein levels was not significant, demonstrating a lack of association between systemic inflammation and orthodontic treatment.
Topics: Humans; Adolescent; Young Adult; Adult; C-Reactive Protein; Prospective Studies; Saliva; Orthodontic Appliances, Fixed; Orthodontic Appliances; Hemoglobins
PubMed: 36941188
DOI: 10.1016/j.ajodo.2023.01.016 -
Scientific Reports Nov 2023The objective of this study was to compare and evaluate the changes in periodontal pathogens and periodontal status within 6 months of wearing three orthodontic...
The objective of this study was to compare and evaluate the changes in periodontal pathogens and periodontal status within 6 months of wearing three orthodontic retainers, namely, vacuum-formed retainer (VFR), Hawley retainer (HR), and lingual fixed retainer (LR). In total, 48 patients who underwent orthodontic treatment with ordinary metal brackets were divided into VFR, HR, and LR groups (n = 16 per group). Saliva samples were collected at the time of debonding (T0) and after 1 month (T1), 3 months (T2), and 6 months (T3). Porphyromonas gingivalis (Pg) and Aggregatibacter actinomycetemcomitans (Aa) were quantitatively analyzed using real-time PCR. Gingival index (GI), plaque index (PLI), and probing depth (PD) were measured at the four time points to evaluate changes in periodontal state. SPSS20.0 software was used to analyze the data, and P < 0.05 was considered statistically significant. The trial was registered at the Chinese Clinical Trial Registry (ChiCTR2300073704), the registration was retrospective. Compared to baseline (T0) values, Pg, Aa, GI, PLI, and PD were significantly decreased in all three groups 1 month after wearing the retainer (p < 0.05). Significant differences were observed in Aa at T3 among the three groups, whereby the HR group exhibited significantly better results compared to the VFR and LR groups (p < 0.05). Differences were found among the three groups' Porphyromonas gingivalis at T3, and the HR group was significantly better than the VFR and LR groups (P < 0.05). From T1 to T2, GI, PLI, and PD of the three groups tended to be stable, however differences were observed at T3, with the PLI and PD of the HR group being the lowest among the three groups (p < 0.05). Regardless of the type of retainer used, the periodontal condition of patients was significantly improved after removal of the metal brackets. After 6 months of retainer use, the Hawley retainer was superior to vacuum-formed retainer and lingual fixed retainer with regard to Pg, Aa, and periodontal clinical parameters.
Topics: Humans; Orthodontic Retainers; Retrospective Studies; Porphyromonas gingivalis; Orthodontic Appliances, Fixed; Gingival Diseases
PubMed: 38001102
DOI: 10.1038/s41598-023-46922-2 -
Heliyon Sep 2023This study aimed to develop an ultraminiature pressure sensor array to measure the force exerted on teeth. Orthodontic force plays an important role in effective, rapid,...
This study aimed to develop an ultraminiature pressure sensor array to measure the force exerted on teeth. Orthodontic force plays an important role in effective, rapid, and safe tooth movement. However, owing to the lack of an adequate tool to measure the orthodontic force in vivo, it remains challenging to determine the best orthodontic loading in clinical and basic research. In this study, a three-dimensional (3D) orthodontic force detection system based on piezoresistive absolute pressure sensors was designed. The 3D force sensing array was constructed using five pressure sensors on a single chip. The size of the sensor array was only 4.1 × 2.6 mm, which can be placed within the bracket base area. Based on the barometric calibration, conversion formulas for the output voltage and pressure of the five channels were constructed. Subsequently, a 3D linear mechanical simulation model of the voltage and stress distribution was established using 312 tests of the applied force in 13 operating modes. Finally, the output voltage was first converted to pressure and then to the resultant force. The 3D force-detection chip was then tested to verify the accuracy of force measurement on the teeth. Based on the test results, the average output force error was only 0.0025 N (0.7169%) (p = 0.958), and the average spatial positioning error was only 0.058 mm (p = 0.872) on the X-axis and 0.050 mm (p = 0.837) on the Y-axis. The simulation results were highly consistent with the actual force applied (intraclass correlation efficient (ICC): 0.997-1.000; p < 0.001). Furthermore, through in vivo measurements and a finite element analysis, the movement trends generated when the measured orthodontic forces that acted on the teeth were simulated. The results revealed that the device can accurately measure the orthodontic force, representing the first clinical test of an orthodontic-force monitoring system. Our study provides a hardware basis for clinical research on efficient, safe, and optimal orthodontic forces, and has considerable potential for application in monitoring the biomechanics of tooth movement.
PubMed: 37809553
DOI: 10.1016/j.heliyon.2023.e19852 -
Orthodontics & Craniofacial Research Dec 2023To investigate the effect of printing material and air abrasion of bracket pads on the shear bond strength of 3D-printed plastic orthodontic brackets when bonded to the...
OBJECTIVE
To investigate the effect of printing material and air abrasion of bracket pads on the shear bond strength of 3D-printed plastic orthodontic brackets when bonded to the enamel of extracted human teeth.
MATERIALS AND METHODS
Premolar brackets were 3D-printed using the design of a commercially available plastic bracket in two biocompatible resins: Dental LT Resin and Dental SG Resin (n = 40/material). 3D-printed brackets and commercially manufactured plastic brackets were divided into two groups (n = 20/group), one of which was air abraded. All brackets were bonded to extracted human premolars, and shear bond strength tests were performed. The failure types of each sample were classified using a 5-category modified adhesive remnant index (ARI) scoring system.
RESULTS
Bracket material and bracket pad surface treatment presented statistically significant effects for shear bond strengths, and a significant interaction effect between bracket material and bracket pad surface treatment was observed. The non-air abraded (NAA) SG group (8.87 ± 0.64 MPa) had a statistically significantly lower shear bond strength than the air abraded (AA) SG group (12.09 ± 1.23 MPa). In the manufactured brackets and LT Resin groups, the NAA and AA groups were not statistically significantly different within each resin. A significant effect of bracket material and bracket pad surface treatment on ARI score was observed, but no significant interaction effect between bracket material and pad treatment was found.
CONCLUSION
3D-printed orthodontic brackets presented clinically sufficient shear bond strengths both with and without AA prior to bonding. The effect of bracket pad AA on shear bond strength depends on the bracket material.
Topics: Humans; Surface Properties; Dental Bonding; Orthodontic Brackets; Air Abrasion, Dental; Shear Strength; Printing, Three-Dimensional; Materials Testing; Resin Cements; Dental Stress Analysis
PubMed: 37102401
DOI: 10.1111/ocr.12667 -
European Journal of Dentistry Feb 2024To evaluate and compare the friction of different ligature modes used in orthodontics, and to propose a new ligature model for conventional brackets ("H low-friction...
OBJECTIVE
To evaluate and compare the friction of different ligature modes used in orthodontics, and to propose a new ligature model for conventional brackets ("H low-friction orthodontic ligature).
MATERIALS AND METHODS
Samples were randomly divided into seven experimental groups: (1) resin H ligature (H3D), designed by the authors of this study and produced in a 3D printer, with conventional bracket; (2) metal H ligature (HFM), with conventional bracket; (3) passive self-ligating bracket (SLP); (4) "8" low-friction unconventional elastic (LT8), with conventional bracket; (5) loose conventional metal ligature (MLS), with conventional bracket; (6) conventional metal ligature fully tightened (MLT), with conventional bracket; (7) conventional elastic ligature (CEL), with conventional bracket-control. All samples were subjected to mechanical static friction testing using the EMIC DL 2000 universal testing machine.
STATISTICAL ANALYSIS
To assess the normality requirement, the Shapiro-Wilk test was used, which showed a non-normal distribution for the means of the groups ( < 0.05). Therefore, statistical tests were performed to assess the existence of statistically significant differences between the groups through the Kruskal-Wallis, followed by Dunn's test, pairwise comparison, < 0.05.
RESULTS
The results obtained showed lower friction values for HFM (0.002 kgf), SLP (0.003 kgf), and LT8 (0.004 kgf)-these did not differ statistically from each other. These were followed by H3D (0.020 kgf), MLS (0.049 kgf), CEL (0.12 kgf), and, finally, MLT (0.21 kgf).
CONCLUSION
The lowest friction value was found for the metal H ligature, similar to the self-ligating bracket and the "8" low-friction unconventional elastic. The resin H ligature presented intermediate friction values and the highest friction force was found for the MLT group.
PubMed: 37311551
DOI: 10.1055/s-0043-1768471 -
European Journal of Orthodontics Sep 2023To evaluate the effect of high-fluoride mouth rinse and high-fluoride toothpaste on the development of demineralized lesions (DLs) during orthodontic treatment. (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVE
To evaluate the effect of high-fluoride mouth rinse and high-fluoride toothpaste on the development of demineralized lesions (DLs) during orthodontic treatment.
TRIAL DESIGN
Three-armed parallel-group randomized controlled trial.
METHODS
The trial was performed with 270 adolescent orthodontic patients. Randomization was performed in blocks of 30, enrolling the patients into one of the following groups: the fluoride mouth rinse (FMR) group receiving 0.2% sodium fluoride (NaF) mouth rinse plus 1450 ppm fluoride (F) toothpaste; high-fluoride toothpaste (HFT) group receiving 5000 ppm F toothpaste; and the Control (CTR) group receiving 1450 ppm F toothpaste. Inclusion criteria were patients scheduled for treatment in both arches with fixed appliances and age between 12 and 20 years. The primary outcome variable was the proportion of participants with at least one new demineralized lesion as assessed on digital photos taken before and after treatment, analysed by a blinded clinician. The analysis included all teeth or teeth in the aesthetic zone, i.e. all central incisors, lateral incisors, and canines. A random sample of 30 participants was assessed to check intra- and inter-reliability. For pairwise comparison between groups, Fisher's non-parametric permutation test was used for continuous variables. Blinding was employed during the caries registration and data analysis.
RECRUITMENT
October 2010 to December 2012.
RESULTS
In total, 270 patients were randomized, of which 22 were excluded during treatment. Therefore, 248 participants were included in the study. The number of patients with an increase of ≥1 DL, including only central- and lateral incisors and canines, during orthodontic treatment, was significantly lower in the HFT group, 51/85 60%, compared to the CTR group, 64/82 78%, RR 0.77 (CI 0.62; 0.95), P = .01 and in the FMR group, 47/81 58%, compared to the CTR group, RR 0.74 (CI 0.60; 0.92), P < .01.
CONCLUSIONS
To prevent demineralized lesions in the aesthetic zone, high-fluoride mouth rinse and high-fluoride toothpaste may be recommended.
LIMITATIONS
The protocol was not registered, and the present study did not use a double-blinded design.
Topics: Adolescent; Humans; Child; Young Adult; Adult; Fluorides; Toothpastes; Mouthwashes; Reproducibility of Results; Esthetics, Dental; Dental Caries; Sodium Fluoride; Cariostatic Agents
PubMed: 37524332
DOI: 10.1093/ejo/cjad044 -
The Saudi Dental Journal Sep 2023This study aimed to evaluate enamel surface roughness and microhardness following the use of different bracket materials (metal or ceramic), etchants (total- and...
BACKGROUND
This study aimed to evaluate enamel surface roughness and microhardness following the use of different bracket materials (metal or ceramic), etchants (total- and self-etchants), and adhesive systems (precoated or flash-free).
METHOD
A total of 99 extracted human premolars were selected for the analysis. The surface roughness was first assessed (roughness control). One specimen from each subgroup was examined using a scanning electron microscope to illustrate the surface topography. Eighty-eight teeth were prepared using total- or self-etchants and bonded to precoated or flash-free adhesive metal or ceramic brackets. The remaining 11 specimens were not bonded to brackets (microhardness controls). The brackets were debonded after immersion in distilled water for 24 h. The specimens were again scanned for surface roughness and topography imaging. Finally, the microhardness was assessed using a micro-Vickers hardness test at a force of 200 g for 10 s.
RESULT
An overall statistically significant increase in surface roughness and reduced surface microhardness were observed in all experimental groups when compared with those in the control groups. The etchant type was the only variable found to contribute to the measured surface properties, with increased roughness and reduced microhardness introduced by total-etching compared to those by self-etching.
CONCLUSION
Orthodontic brackets introduced a significant increase in enamel surface roughness and reduce microhardness compared with untreated enamel, regardless of the bracket material, etchant type, and adhesive system. The etchant type was the only variable contributing to these changes, with total etching having a more pronounced effect.
PubMed: 37817787
DOI: 10.1016/j.sdentj.2023.05.015