scholarly journals Evaluation of enamel roughness after the removal of brackets bonded with different materials: In vivo study

2021 ◽  
Vol 32 (5) ◽  
pp. 34-40
Author(s):  
Rodrigo Vieira Caixeta ◽  
Sandrine Bittencourt Berger ◽  
Murilo Baena Lopes ◽  
Eloisa Aparecida Carlesse Paloco ◽  
Élcio Mário Faria-Júnior ◽  
...  

Abstract The aims of this in vivo study were to evaluate the effect of bonding with resin-modified glass ionomer cement (RMGIC) and to assess enamel surface roughness before and after the removal of brackets bonded with composite or RMGIC from the maxillary central incisors. Fifteen orthodontic patients were selected for the study. For each patient, the teeth were rinsed and dried, and brackets were bonded with composite (Transbond XT) and RMGIC (Vitremer Core Buildup/Restorative). At the conclusion of orthodontic treatment, their brackets were removed. Dental replicas were made of epoxy resin in initial conditions (before bonded) and after polishing with an aluminum oxide disc system. Adhesive remnant index (ARI) and surface roughness was measured on the dental replicas and data were evaluated statistically by Mann-Whitney and paired t-test, respectively. No bracket debonding occurred during patients’ treatment periods. It was verified that the ARI values of the two maxillary central incisors were similar (p = 0.665). For both bonding materials, the ARI value of 3 was predominant. After polishing, surface roughness was similar in the composite and RMGIC groups (0.245 μm and 0.248 μm, respectively; p = 0.07). In both groups, enamel surface roughness values were significantly lower after polishing compared with the initial condition (p < 0.001). RMGIC promoted efficiency in cementing brackets without fail during treatment; the choice of composite or RMGIC materials was not a factor that influenced the roughness of the enamel surface, however, polishing led to smoother surfaces than those found at the beginning of the treatment.

2019 ◽  
Vol 22 (1) ◽  
pp. 12-14
Author(s):  
Astrid Yudhit ◽  
Kholidina Imanda Harahap ◽  
Yuli Ratna Dewi

Resin modified glass ionomer cement as restorative material used in dentistry especially in primary teeth. Fresh milk is often consumed by children as daily drink and it contains lactic acid. The aim of this study was to evaluate surface roughness of resin modified glass ionomer cement after immersed in fresh milk for 2, 4, and 6 hours. Samples were disc shape resin modified glass ionomer cement with size 5 mm in diameter and 2 mm in thickness. Totally 24 samples were divided into 3 groups (n=8), group immersed for 2 hours, group immersed for 4 hours, and group immersed for 6 hours. Fresh milk was pure cow’s milk that harvest in the morning by the farmer. Surface roughness measurements was done before and after immersed using a profilometer (Surfcorder SE-300, Laboratory Ltd, Japan). Results showed surface roughness change were 0.0217 ± 0.005 μm for groups A, 0.0366 ± 0.006 μm for groups B, and 0.0555 ± 0.004μm for groups of 6 hours. One Way Anova test showed significant differences between groups (p <0.05). It can be concluded that there was significant increased on surface roughness of modified resin ionomer cement after immersed in fresh milk for 2, 4 and 6 hours.    


2018 ◽  
Vol 43 (1) ◽  
pp. 51-59 ◽  
Author(s):  
I Wongpraparatana ◽  
O Matangkasombut ◽  
P Thanyasrisung ◽  
M Panich

SUMMARY Objective: To compare the effect of simulated bleaching with a 10% carbamide peroxide (CP) or a 40% hydrogen peroxide (HP) system on surface roughness of resin composite and resin-modified glass ionomer cement (RMGI) and streptococcal biofilm formation on these surfaces. Methods and Materials: Streptococcus mutans , Streptococcus sanguinis , and trypticase soy broth control for 24 hours. Biofilm formation was quantified by crystal violet staining, and the structure was visualized by scanning electron microscopy. The differences between the mean changes in Ra between the 10% CP and 40% HP groups of each material were evaluated with an independent t -test. The quantity of biofilm formation on each material was analyzed with one-way analysis of variance with the post hoc Tukey test ( α =0.05).Specimens of nanofilled resin composite and RMGI (n=108 each) were randomly divided into three groups (n=36 each): no treatment control, 10% CP, and 40% HP. The surface roughness values (Ra) were measured before and after treatments. The specimens in each group were randomly divided into three subgroups (n=12) and incubated with Results: S. mutans biofilm formation, bleaching with 10% CP and 40% HP increased biofilm on both materials compared to controls. However, S. sanguinis biofilm formation was significantly higher on bleached resin composite but not on RMGI specimens.Surface roughness significantly increased after bleaching in all groups. There was no significant difference between the 10% CP and 40% HP groups of each material. For Conclusions: S. sanguinis biofilm on RMGI.Simulated bleaching with 10% CP or 40% HP increased both surface roughness and biofilm formation on resin composite and RMGI, except for


2018 ◽  
Vol 6 (6) ◽  
pp. 922-931
Author(s):  
Hina Desai ◽  
Pooja Yadav ◽  
Sarvesh Agrawal ◽  
Kalpesh Patel ◽  
Malhar Oza ◽  
...  

2020 ◽  
Author(s):  
Stefano Mandija ◽  
Petar I. Petrov ◽  
Jord J. T. Vink ◽  
Sebastian F. W. Neggers ◽  
Cornelis A. T. van den Berg

AbstractFirst in vivo brain conductivity reconstructions using Helmholtz MR-Electrical Properties Tomography (MR-EPT) have been published. However, a large variation in the reconstructed conductivity values is reported and these values differ from ex vivo conductivity measurements. Given this lack of agreement, we performed an in vivo study on eight healthy subjects to provide reference in vivo brain conductivity values. MR-EPT reconstructions were performed at 3 T for eight healthy subjects. Mean conductivity and standard deviation values in the white matter, gray matter and cerebrospinal fluid (σWM, σGM, and σCSF) were computed for each subject before and after erosion of regions at tissue boundaries, which are affected by typical MR-EPT reconstruction errors. The obtained values were compared to the reported ex vivo literature values. To benchmark the accuracy of in vivo conductivity reconstructions, the same pipeline was applied to simulated data, which allow knowledge of ground truth conductivity. Provided sufficient boundary erosion, the in vivo σWM and σGM values obtained in this study agree for the first time with literature values measured ex vivo. This could not be verified for the CSF due to its limited spatial extension. Conductivity reconstructions from simulated data verified conductivity reconstructions from in vivo data and demonstrated the importance of discarding voxels at tissue boundaries. The presented σWM and σGM values can therefore be used for comparison in future studies employing different MR-EPT techniques.


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