18 research outputs found
Comparison of the High Cycle Fatigue Behavior of the Orthodontic NiTi Wires: An in Vitro Study
Objective: To compare the high-cycle fatigue behavior of four commercially available NiTi orthodontic wires. Material and Methods: Twelve NiTi orthodontic wires, round, 0.016-in, three per brand, were selected and divided into four groups: G1 - Heat-activated NiTi, G2 - Superelastic NiTi, G3 - Therma-Ti, and G4 - CopperNiTi. The atomic absorption spectrometry method was used to determine the chemical composition of investigated NiTi wires. We also performed a fatigue test at three-point bending using a universal testing machine for 1000 cycles in a 35 °C water bath. For the first and thousandth cycle, the average plateau load and the plateau length were determined in the unloading area of the force versus displacement diagram. In addition, we calculated the difference between the average plateau load of the first and thousandth cycle (∆F), as well as the difference between the plateau length of both cases (∆L). Results: According to our results, there were no significant differences between the average plateau load of the first and thousandth cycles of each group (p>0.05) and in the plateau length of the first and thousandth cycles of the groups (p>0.05). Conclusion: There were no significant differences between the groups changing the superelasticity property after high-cycle fatigue
Combined chlorhexidine-sodiumfluoride mouthrinse for orthodontic patients: clinical and microbiological study
Background: Orthodontic appliances impede good dental plaque control by brushing. Antimicrobial mouth rinses
were suggested to improve this performance. We therefore aimed to investigate the effects of combined mouthrinse
containing chlorhexidine (CHX) and sodium fluoride (NaF) on clinical oral hygiene parameters,and plaque bacterial level.
Material and Methods: In this double-blind clinical study, 60 fixed orthodontic patients aged 14-25 years were
randomly assigned to one of four mouthrinses groups: 1- combined CHX /NaF 2- CHX 0.06% 3- NaF0.05%
4-placebo. Following baseline examination patients were instructed to use the assigned mouthrinse twice daily for
21 days. Bleeding index (BI), modified gingival index (MGI) and plaque index (PI) were determined at the baselineand after three weeks of rinsing. Samples from supragingival plaque were obtained for the assessment of total
bacterial,
Streptococcus mutans
and
Lactobacilli
colony counts. Data were analyzed by Wilcoxon, Kruskal-Wallis,
and Mann-Whitney tests.
Results: Clinical parameters; All three active mouth rinses induced significant improvements of BI, MGI, and PI
(
P
<0.05). Results of CHX/NaF were slightly, but not significantly, better than CHX. CHX/NaF and CHX induced
significantly more changes than NaF and placebo. Microbiological measurements; Except placebo, other mouthrinses reduced total bacterial,
Streptococcus mutans
, and
Lactobacilli
counts significantly (
P
<0.05). CHX/NaF acted
against
Lactobacilli
significantly more than others.
Conclusions: Adding CHX0.06%/NaF0.05% combined mouth rinse to daily oral hygiene regimen of orthodontic
patients significantly improved oral hygiene status. Effect of this combined mouth rinse on dental plaque
Lactobacilli
was remarkable. However, large controlled trials could provide more definitive evidence
Introducing a User-Friendly Technique for Treatment of Palatally-Impacted Canines with the Aid of Temporary Anchorage Devices
Treatment of impacted canine teeth is a challenge for most clinicians, especially in adult patients with high risk of ankylosis. Conventionally, leveling and alignment of the teeth are first performed and after heavy arch wire placement in slot of brackets, de-impaction force is applied. However, this method has some disadvantages, such as inability to detect ankylosis of the impacted tooth until load application, risk of root resorption of incisors or necrosis of them, distortion of dental arch form, the need for early extraction of primary canines, which is esthetically unfavorable for patients, and long-term presence of fixed orthodontic appliances in the oral cavity. This study aims to introduce approach that can be easily used by busy clinicians to guide palatally impacted canines into the dental arch using a cantilever spring supported by two palatal miniscrews prior to the initiation of fixed orthodontic treatment, and report some cases treated with this technique. This technique does not have the shortcomings of the conventional technique. In addition, the total duration of treatment, and duration of presence of orthodontic appliances in the oral cavity are shorter than the conventional technique. In addition, is less technique sensitive and do not need time complex and time consuming wire bending
Effect of ibuprofen and low-intensity pulsed ultrasound on the reduction of pain after initial archwire placement: a double-blind randomized clinical trial
Objective: This study aimed to compare the effect of ibuprofen and low-intensity pulsed ultrasound (LIPUS) on the reduction of pain after the placement of initial archwire in orthodontic patients.
Material and Methods: This double-blind clinical trial study was carried out on 60 female candidates for fixed orthodontic treatment referring to the Orthodontic Department of School of Dentistry in Mashhad University of Medical Sciences, Mashhad, Iran, during 2015-2016. The subjects were divided into four groups of ibuprofen, LIPUS, placebo, and mock LIPUS. A questionnaire and a rectangular and flexible cubic silicone were given to each patient to record the severity of pain based on the visual analog scale at specified time points (i.e., 2 h, 6 h, at bedtime, 2nd, 3rd, and 7th days after archwire placement) when biting the silicone block with the anterior and posterior teeth and without biting at all. Repeated measures analysis of variance was used in order to compare the pain severity at different time points.
Results: The comparison of pain severity at various time points showed that the highest and lowest mean scores of pain were reported at bedtime and seven days after the intervention (p0.05).
Conclusion: In conclusion, LIPUS (with a frequency of 1 MHz and an intensity of 100 mW) and ibuprofen have no significant effects on reduction of the pain severity at different time points and various conditions in orthodontic patients
The effect of low level laser on condylar growth during mandibular advancement in rabbits
<p>Abstract</p> <p>Introduction</p> <p>It has been shown that Low Level Laser (LLL) has a positive effect on bone formation. The aim of this study was to evaluate the effect of low level laser on condylar growth during mandibular advancement in rabbits.</p> <p>Materials and methods</p> <p>Continuous forward mandibular advancement was performed in fourteen male Albino rabbits with the mean age of 8 weeks and the mean weight of 1.5 ± 0.5 kg, with acrylic inclined planes. The rabbits were randomly assigned into two groups after 4 weeks. LLL (KLO3: wave length 630 nm) was irradiated at 3 points around the TMJ, through the skin in the first group. The exposure was performed for 3 minutes at each point (a total of 9 minutes) once a day for 3 weeks. The control group was not exposed to any irradiation. The rabbits in both groups were sacrificed after two months and the histological evaluation of TMJ was performed to compare fibrous tissue, cartilage, and new bone formation in condylar region in both groups. Disc displacement was also detected in both groups. Student's t-test, Exact Fisher and Chi square tests were used for the statistical analysis.</p> <p>Results</p> <p>The formation of fibrous tissue was significantly lower, while bone formation was significantly greater in lased group as compared with control group. The thickness of cartilage did not differ significantly between two groups.</p> <p>Conclusion</p> <p>Irradiation of LLL (KLO3) during mandibular advancement in rabbits, increases bone formation in condylar region, while neither increase in the cartilage thickness nor fibrous tissues was observed.</p
Molar Uprighting Using Mini-Screws after Distalization by the Pendulum Appliance: A Case Report
A 16-year-old Class II female patient was treated without tooth extraction. The upper first molars were distalized by the Pendulum appliance. After six months, the molars tipped significantly to the distal. To correct this side effect, we decided to upright the molars using skeletal anchorage. On each side, a mini-screw was inserted between first and second premolars in the buccal cortical plate. An auxiliary spring was placed between the mini-screw head and the molar buccal tube. The resultant moment made the first molar upright. In addition, the side effects of this mechanic, i.e. molar intrusion and molar buccal tipping, counteract the extrusion and medial movement caused by the Pendulum Appliance. The aim of this case report was to present an innovative method for molar uprighting using skeletal anchorage
How Is the Enamel Affected by Different Orthodontic Bonding Agents and Polishing Techniques?
Objectives: The objective of this study was to assess the effect of new bonding techniques on enamel surface.
Materials and Methods: Sixty upper central incisors were randomly divided into two equal groups. In the first group, metal brackets were bonded using Trans- bondXT and, in the second group, the same brackets were bonded with MaxcemElite. The shear bond strength (SBS) of both agents to enamel was measured and the number and length of enamel cracks before bonding, after debonding and after polishing were compared. The number of visible cracks and the adhesive remnant index (ARI) scores in each group were also measured.
Results: There were significantly more enamel cracks in the Transbond XT group after debonding and polishing compared to the Maxcem Elite group. There was no significant difference in the length of enamel cracks between the two groups; but, in each group, a significant increase in the length of enamel cracks was noticeable after debonding. Polishing did not cause any statistically significant change in crack length. The SBS of Maxcem Elite was significantly lower than that of Transbond XT (95% confidence interval).
Conclusion: Maxcem Elite offers clinically acceptable bond strength and can thus be used as a routine adhesive for orthodontic purposes since it is less likely todamage the enamel
Comparison of esthetics perception and satisfaction of facial profile among male adolescents and adults with different profiles
Objective: To evaluate esthetics perception and satisfaction of the facial profile among Iranian male adolescents and adults.
Materials and Methods: In this cross-sectional study, male subjects referred to Orthodontic Department of Mashhad Dental School were enrolled (n = 84) and were divided into two groups: Adolescents (n = 39), and adults (n = 45). They were also assigned to straight, convex, or concave profile groups based on the facial profile angle (G-Sn-Pog′). An ideal silhouette of the lower facial profile was designed in Adobe® Photoshop® CS2 software (Kansas, USA). Then, eight other silhouettes representing different relations of the maxilla and mandible were constructed. Patients were asked to use numbers 1-10 to rank the facial profiles in the order of the attractiveness, and choose a silhouette that best closely resembled their own profile. Moreover, using a questionnaire patients were asked to rank their satisfaction with their profile, and asked to assign a number (1-5) to each question as follows; one represented the least satisfaction, while five reflected the highest satisfaction.
Results: Adult and adolescent subjects with straight (adults: 12.0 ± 1.9, adolescents: 12.8 ± 1.05) and concave (adults: 10.0 ± 2.14, adolescents: 10.0 ± 2.08) profile showed the highest and the least satisfaction with their own profile, respectively. Both adult and adolescent group selected "retrognathic maxilla, prognathic mandible" as the least attractive profile. Overall, "straight" and "bimaxillary dentoalveolar retrusion" were chosen as the most attractive silhouettes in adolescent and adults, respectively. In comparison to a professional opinion (clinician ranking), 42.9% of adolescents and 22% of adults were able to correctly diagnose their own profiles type.
Conclusion: Most of the male adolescents and especially adults diagnosis of their own profile differed with a professional assessment
Effects of Magnesium Oxide Nanoparticles Incorporation on Shear Bond Strength and Antibacterial Activity of an Orthodontic Composite: An In Vitro Study
This study aimed to evaluate the effects of magnesium oxide (MgO) nanoparticle (NP) incorporation on shear bond strength (SBS) and antibacterial property of orthodontic composites. A total of 100 mounted premolar teeth were randomly divided into five groups. In group 1 (control), the brackets were bonded to the teeth using the GC Ortho Connect orthodontic composite, while the brackets of groups 2 to 5 were bonded by the GC Ortho Connect orthodontic composite that contained 0.5%, 1%, 2%, and 4% weight percentages (w/w) of MgO NPs, respectively and then the SBS was measured. In the following, we evaluated the antibacterial properties of the MgO NP-containing composite on Streptococcus mutans (S. mutans) bacteria by the direct contact test method. According to results, there were no significant changes in the SBS as the MgO NP concentration was increased up to 1%, while the SBSs of the 2% and 4% MgO NPs were decreased when compared to the other three groups. The outcomes of the direct contact test indicated the case of 1% as being the minimum ratio of MgO NPs, which almost caused the entire annihilation of the S. mutans bacteria. In conclusion, the orthodontic composite containing 1% MgO NPs can display a significant antibacterial effect against S. mutans bacteria without inducing any negative effect on the SBS
Comparison of three different sterilization and disinfection methods on orthodontic markers
Background: Marking pencils which are frequently used in orthodontics may cause microbial contamination. The purpose of this study was to evaluate and compare the effectiveness of three disinfection and sterilization methods (autoclave, glutaraldehyde solution, and Deconex spray) on orthodontic markers.
Materials and Methods: One hundred and twenty orthodontic markers were divided into four groups each 30 pencils: One control group and three groups for three different disinfection/sterilization methods. To evaluate the effectiveness of these methods, pencils were initially contaminated by common pathogen by immersing the pencils in a suspension containing 1.5 × 10 8 CFU/ml organisms. Then, the pencils were subjected to corresponding disinfection/sterilization methods, and the number of remaining microorganisms was calculated and compared with control group.
Results: In the control group, the mean number of Escherichia coli was significantly higher than the other two microorganisms (P = 0.01, P = 0.031). However, the mean numbers of Staphylococcus aureus and Candida albicans were not significantly different (P = 0.1). After sterilization with autoclave and glutaraldehyde, no microbial growth was observed, whereas after disinfection with Deconx spray some colonies of microorganisms still could be observed.
Conclusion: Autoclaving and glutaraldehyde solution are the best methods for disinfecting orthodontic markers