Efficacy of Fluoride Varnish with Casein Phosphopeptide and Amorphous Calcium Phosphate vs Fluoride Varnish in Prevention of White Spots Lesion in fixed Orthodontic Patients: In Vivo Study

AIM

The aim of the study is to compare the in vivo efficiency of Michigan (MI) varnish containing casein phosphopeptide (CPP) and amorphous calcium phosphate (ACP) and Fluoritop containing sodium fluoride (5% NaF) in the prevention and remineralization of white spot lesions (WSLs) around orthodontic brackets at days 28 and 56 after bonding.

MATERIALS AND METHODS

A total of 30 patients were selected and divided into two groups I (MI varnish) II (Fluoritop varnish) of 15 patients in each group. All the patients were bonded and then varnish was applied around the brackets. Right-side upper and lower first premolar teeth were taken as the control group and left-side upper and lower first premolar teeth as the experimental group. Also, 14, 24 teeth were extracted on day 28 after bonding and 34, 44 teeth after day 56 of bonding. Samples were collected and sent to laboratory for evaluation of surface microhardness (SMH).

RESULTS

Based on the statistics results, there was a significant decrease in demineralization and an increase in remineralization of WSLs after the application of varnish. No statistical significance was found between the effectiveness of MI varnish and Fluoritop except in the cervical region.

CONCLUSION

Through our study, we concluded that no statistical significance was found between the effectiveness of MI varnish and Fluoritop except in the cervical region where MI varnish was found to be more effective than Fluoritop in preventing WSLs.

CLINICAL SIGNIFICANCE

The results from the above study concluded that CPP-ACP varnish can be an effective method in preventing WSLs in patients undergoing fixed orthodontic treatment.

Immediate and Delayed Effects of Diode Laser on Debonding of Ceramic Brackets: An in vitro Study

AIM

The aim of the study is to evaluate the immediate and delayed effects of diode laser on debonding of ceramic brackets.

MATERIALS AND METHODS

A total of 60 human extracted premolar teeth were randomly assigned to three different treatment groups. All teeth were bonded with adhesive precoated (APC) ceramic brackets (3M Unitek). A total of 20 teeth were debonded without lasing (group 1), 20 immediately after lasing (group 2), and 20 1 hour after lasing (group 3). For the lasing groups (groups 2 and 3), access cavity was prepared on the occlusal surface to a 2 mm diameter. A transbond plus self-etching primer (3M Unitek, Monrovia, CA, USA) and APC PLUS clarity advanced brackets (3M, Unitek, Monrovia, CA, USA) were used. The shear bond strength (SBS) and adhesive remnant index (ARI) were measured. The internal pulpal wall temperature was noted for the laser groups.

RESULTS

The mean SBS was 15.4, 11.57, and 11.79 MPa for groups 1 to 3 respectively. Post hoc test showed significant difference (p < 0.001) between the control group and the lased groups. For groups 2 and 3, the rise in temperature was at an average of 1.4 and 1.3°C respectively.

CONCLUSION

The SBS of APC brackets decreased by 33.3% on application of diode laser without increasing the internal pulp chamber wall temperature significantly. Shear bond strength remains more or less the same whether debonding is done immediately after lasing or 1 hour after lasing. Diode lasers increased the ARI scores and thus decreased the risk of enamel fracture.

An Accurate Methodology to detect Leaching of Nickel and Chromium Ions in the Initial Phase of Orthodontic Treatment: An in vivo Study

AIM

The aim of this study was to evaluate the release of nickel and chromium ions in human saliva during fixed orthodontic therapy.

MATERIALS AND METHODS

Ten patients with Angle's Class-I malocclusion with bimaxillary protrusion without any metal restorations or crowns and with all the permanent teeth were selected. Five male patients and five female patients in the age group range of 14 to 23 years were scheduled for orthodontic treatment with first premolar extraction. Saliva samples were collected in three stages: sample 1, before orthodontic treatment; sample 2, after 10 days of bonding sample; and sample 3, after 1 month of bonding. The samples were analyzed for the following metals nickel and chromium using inductively coupled plasma optical emission spectrometry (ICP-OES).

RESULTS

The levels of nickel and chromium were statistically significant, while nickel showed a gradual increase in the first 10 days and a decline thereafter. Chromium showed a gradual increase and was statistically significant on the 30th day.

CONCLUSION

There was greatest release of ions during the first 10 days and a gradual decline thereafter. Control group had traces of nickel and chromium. While comparing levels of nickel in saliva, there was a significant rise from baseline to 10th and 30th-day sample, which was statistically significant. While comparing 10th day to that of 30th day, there was no statistical significance. The levels of chromium ion in the saliva were more in 30th day, and when comparing 10th-day sample with 30th day, there was statistical significance.

CLINICAL SIGNIFICANCE

Nickel and chromium levels were well within the permissible levels. However, some hypersensitive individuals may be allergic to this minimal permissible level.

A hard tissue cephalometric comparative study between hand tracing and computerized tracing

Aims:

To analyze and compare the angular and linear hard tissue cephalometric measurements using hand-tracing and computerized tracings with Nemoceph and Dolphin software systems.

Subjects and Methods:

A total of 30 cephalograms were randomly chosen for study with the following criteria, cephalograms of patients with good contrast, no distortion, and minimal radiographic artifacts were considered using the digital method (Kodak 8000 C) with 12 angular and nine linear parameters selected for the study. Comparisons were determined by post-hoc test using Tukey HSD method. The N-Par tests were performed using Kruskal-Walli's method.

Statistical Analysis Used:

ANOVA and post-hoc.

Results:

The results of this study show that there is no significant difference in the angular and linear measurements recorded. The P values were significant at 0.05 levels for two parameters, Co-A and Co-Gn with the hand-tracing method. This was significant in ANOVA and post-hoc test by Tukey HSD method.

Conclusions:

This study of comparison provides support for transition from digital hand to computerized tracing methodology. In fact, digital computerized tracings were easier and less time consuming, with the same reliability irrespective of each method of tracing.

9-[4-(Azido-meth-yl)phen-yl]-9H-carbazole-3-carbo-nitrile

In the title compound C₂₀H₁₃N₅, the dihedral angle between the carbazole ring system (r.m.s. deviation = 0.027 Å) and the pendant benzene ring is 55.08 (6)°. One of the azide N atoms is disordered over two positions in a 0.65 (2):0.35 (2) ratio. In the crystal, aromatic π–π stacking is observed [minimum centroid–centroid separation = 3.6499 (13) Å] as well as inversion-dimers connected by pairs of weak C—H⋯π inter­actions.

1-[6-(1H-Indol-1-yl)pyridin-2-yl]-1H-indole-3-carbaldehyde

In the title compound, C₂₂H₁₅N₃O, the dihedral angle between the two indole units is 33.72 (3)°. The mol­ecular structure features a weak intra­molecular C—H⋯N inter­action. In the crystal, weak C—H⋯O and C—H⋯π inter­actions, forming a two-dimensional network parallel to the bc plane.

9-p-Tolyl-9H-carbazole-3-carbonitrile

In the title compound, C₂₀H₁₄N₂, the carbazole ring system is essentially planar (r.m.s. deviation = 0.187 Å) and is inclined at an angle of 54.33 (4) ° with respect to the benzene ring. The crystal packing is stabilized by weak C—H⋯N and C—H⋯π inter­actions.

(E)-1-[4-(Prop-2-yn-1-yl-oxy)phen-yl]-3-(3,4,5-trimeth-oxy-phen-yl)prop-2-en-1-one

The mol­ecule of the title chalcone derivative, C₂₁H₂₀O₅, consists of two substituted aromatic rings bridged by a prop-2-en-1-one group. The dihedral angle between the two benzene rings is 28.7 (7)°. In the crystal, mol­ecules are linked into C(10) chains running along the a axis by inter­molecular C—H⋯O hydrogen bonds, and the chains are cross-linked via C—H⋯π inter­actions.

Trauma from occlusion - An orthodontist′s perspective

Orthodontic therapy has a big role in the treatment and prevention of malpositions. The signs and symptoms experienced by patients with occlusal trauma are mobility of teeth, temperomandibular joint pain, pain on mastication and periodontal disease. Early diagnosis, proper treatment plan and correction of malocclusion can lead to a successful outcome. Lack of awareness of orthodontic treatment in patients with occlusal trauma can even lead to loss of tooth structure.

4,5-Bis(1H-imidazol-1-ylmeth-yl)acridine monohydrate

In the title compound, C(21)H(17)N(5)·H(2)O, the dihedral angles between the acridine ring system and the imidazole rings are 78.8 (1) and 71.2 (1)°. The crystal packing is stabilized by O-H⋯N, C-H⋯O, C-H⋯π and π-π inter-actions [centroid-centroid separations = 3.732 (1) and 3.569 (1) Å].

Evidence for intracellular down-regulation of the epidermal growth factor (EGF) receptor during adenovirus infection by an EGF-independent mechanism

We have reported previously that human group C adenoviruses down-regulate the epidermal growth factor (EGF) receptor (EGF-R) (C. R. Carlin, A. E. Tollefson, H. A. Brady, B. L. Hoffman, and W. S. M. Wold, Cell 57:135-144, 1989). Expression of a 13.7-kDa protein encoded by a gene in the E3 transcription unit is necessary and sufficient for this effect (Carlin et al., Cell, 1989; B. L. Hoffman, A. Ullrich, W. S. M. Wold, and C. R. Carlin, Mol. Cell. Biol. 10:5521-5524, 1990). We show here that EGF-R down-regulation is accelerated in cells which overexpress the receptor when these cells are infected with virus mutants that overproduce the 13.7-kDa protein compared with wild-type virus. This is in contrast to EGF stimulation, for which others have shown that high concentrations of ligand are associated with low rates of receptor internalization in EGF-R-overexpressing cells (D. Kuppuswamy and L. J. Pike, J. Biol. Chem. 264:3357-3363, 1989; H. S. Wiley, J. Cell Biol. 107:801-810, 1988). We also show that the E3 protein is not present in media conditioned by infected cells and that it does not induce secretion of an EGF-like autocrine factor. Moreover, while mature membrane-bound EGF-R is down-regulated, the precursor of the membrane-bound form is not. Adenovirus infection also does not affect receptor-related molecules expressed in the secretory pathway. Interestingly, adenovirus-induced down-regulation is not regulated by concentrations of EGF associated with a slow rate of internalization in A431 cells. This suggests that 13.7-kDa protein expression triggers receptor entry by a novel ligand-independent pathway or, alternatively, that it compensates for a cellular factor that may be rate limiting during EGF-mediated endocytosis.