Z Tavakolinejad, Hr Razeghi, M Sadeghi,
Volume 6, Issue 1 (3-2021)
Abstract
Background and Aim: Orthodontic patients are at an increased risk of caries due to difficulty in plaque control. Antimicrobial agents, such as fluoride and chlorhexidine, can be useful in preventing tooth demineralization. The present study aimed to determine the effect of fluoride and chlorhexidine gels and their mixture on the shear bond strength (SBS) of orthodontic brackets.
Materials and Methods: In this ex-vivo study, 70 premolars were divided into seven groups. The first group was considered as the control. The second, third, and fourth groups were first etched with 37% phosphoric acid and then pretreated with chlorhexidine, fluoride, and fluoride-chlorhexidine gels, respectively. The brackets were then bonded. In the fifth, sixth, and seventh groups, the enamel surface was etched after pretreatment, and then, the brackets were bonded. After mounting the teeth, SBS was measured using the Instron machine. Data were analyzed using one-way analysis of variance (ANOVA) and Tamhane's T2 test (α≤0.05).
Results: The mean SBS was 19.7 MPa in the control, 11.1±2.5 MPa in the second, 11.8±3.6 MPa in the third, 21±7.5 MPa in the fourth, 19.4±9 MPa in the sixth, and 14.1±6.7 MPa in the seventh group with no statistically significant differences. However, there was a statistically significant decrease in the mean SBS (8±5.2 MPa) of the fifth group (chlorhexidine before etching) compared to the control group (P=0.04).
Conclusion: The use of fluoride and chlorhexidine can be recommended to orthodontic patients because of antibacterial and anticaries properties and no significant decrease in the SBS of orthodontic brackets (except when chlorhexidine is used before etching).
A Aminian, Z Tavakolinejad, H Ebrahimnejad, N Azami,
Volume 6, Issue 3 (6-2021)
Abstract
Background and Aim: This study compares a new technique for teeth alignment to the conventional method. The teeth were aligned using an open-coil spring, i.e. simultaneous space opening and alignment, on round nickel-titanium (NiTi) archwires. The purpose of this 2-arm parallel trial (1:1 allocation ratio) was to evaluate the alignment efficiency of conventional and open-coil spring techniques in anterior crowding treatment.
Materials and Methods: In this clinical trial study, sixty-two non-extraction patients (70 dental arches: 24 upper arches and 46 lower arches) with ≥3mm of Little’s Irregularity Index (LII) were recruited in two groups based on the minimization method. Blinding was applicable for outcome assessment only. In one group, the teeth were aligned using an open-coil spring, whereas the alignment in the other group was done conventionally, (space opening on steel wires followed by alignment with an auxiliary NiTi wire). The alignment duration was the primary outcome that was investigated for survival analysis and alignment rate ratios, and levels of crowding were calculated with Cox proportional hazard regression. The pre- and post-treatment intercanine widths were also recorded as the secondary outcome. The chi-square and t-test were used to compare other variables between the groups. The level of statistical significance was set at P<0.05.
Results: There was no significant difference in the alignment duration between the conventional (185.48±74.82 days) and open-coil (179.19±64.15 days) groups (P=0.725). No harm was detected using the mentioned methods.
Conclusion: The use of open-coil spring over brackets on NiTi or steel wires does not seem to affect anterior crowding treatment time.
Zahra Tavakolinejad, Mahmood Sheikh Fathollahi, Farzaneh Mirzaei, Farzaneh Mirzaei, Elham Mirzaei,
Volume 8, Issue 4 (11-2023)
Abstract
Background and Aim: Formation of white spot lesions, due to plaque accumulation and bacterial biofilm growth, is a common complication in orthodontic treatment. The present study aimed to compare the antibacterial properties of an orthodontic composite containing silver (Ag) and amorphous tricalcium phosphate (ATCP) nanoparticles against Streptococcus mutans (S. mutans).
Materials and Methods: In this in vitro study, 0.3% w/w Ag nanoparticles and 3% w/w ATCP nanoparticles were added to Transbond XT orthodontic composite. Totally, 48 composite discs were fabricated in three groups) n=16). The experimental groups included composite specimens containing nanoparticles and the control group included composite specimens without nanoparticles. The antibacterial effects of composite discs with and without nanoparticles against S. mutans (ATCC 35668) in the three groups were assessed by the direct contact test after 24 hours and 30 days. The number of bacterial colonies was visually counted in the three groups and compared. Data were analyzed by one-way ANOVA and Duncan's multiple comparisons test. P-values under 0.05 were considered significant.
Results: The antibacterial properties of nano-composites significantly increased in both experimental groups of composites containing Ag and ATCP nanoparticles, compared to the control group (P<0.001). The highest antibacterial activity was observed in the orthodontic composite containing ATCP nanoparticles.
Conclusion: Addition of Ag and ATCP nanoparticles to orthodontic light-cure composite increases its antibacterial activity against S. mutans. |
