Comparison of the Effectiveness of Chemo-mechanical and Traditional Caries Removal Methods in Primary Teeth Using Micro-Computed Tomography

Purpose: The purpose of this study was to evaluate dentin mineral density before and after caries removal with the traditional caries removal technique and chemo-mechanical method, with or without the use of caries detection dye. Our null hypothesis was that the chemo-mechanical method with minimally invasive treatment would achieve an effect similar to that of conservative pediatric dentistry treatment. Materials & Methods: Forty-eight medium-sized, interfacial decayed primary molar teeth without pulpal perforation were selected. Two groups were formed by Papacarie Duo and conventional method; then four sub-groups were formed by two caries detection dye applied or not applied groups, twelve teeth were randomly divided into each group. The teeth were then treated with chemo mechanical and traditional caries removal approach. Teeth were scanned with the same voxel sizes using micro-computed tomography images to figure out the difference dentin mineral density and to calculate the removed dentinal volume after chemo-mechanical or traditional method application. Results: The results showed increase of cavity volume in the chemo-mechanical and traditional method groups. No significant difference was found for cavity volume and dentinal carious volume in both groups (p>0.05). The mineral density values of demineralized dentin were between 0.52-0.66 g/cm3 before caries removal, and 1.39-1.59 g/cm3 after removing caries. These values were found to be within the range of healthy dentin mineral density values again without any significant difference between groups (p>0.05). Conclusion: In conclusion, chemo-mechanical methods can be used effectively for removing the caries in the primary molar teeth similar to conservative treatments.

ELASTİK MODÜL YAKLAŞIMI İLE SES HIZLARININ HESAPLANARAK TUNGSTENİN AKUSTİK EMPEDANS ÜZERİNDEKİ ETKİLERİNİN ARAŞTIRILMASI

Some metal filler powders, such as tungsten, are available as support materials in the bodies of ultrasonic transducers. The backing materials consist of two types of epoxy material, mainly hardener and adhesive, and filler powders. One of the reasons why these filler powders are incorporated into epoxy materials is the desire to achieve high acoustic impedance in ultrasonic probes. In this context, samples with different epoxy mixing ratios of tungsten added in amounts of 1, 2, 5 and 10 grams were prepared for the measurement, and the sound velocities used in the calculation of acoustic impedance were calculated over elastic modulus and densities measured by mechanical method. Thus, the effects of tungsten used in the support material in the probes of ultrasound devices were investigated. As a result, the increasing effect of tungsten on acoustic impedance was also determined with the calculations made by mechanical method.

Accurate Prediction of Absorption Spectral Shifts of Proteorhodopsin Using a Fragment-Based Quantum Mechanical Method

Many experiments have been carried out to display different colors of Proteorhodopsin (PR) and its mutants, but the mechanism of color tuning of PR was not fully elucidated. In this study, we applied the Electrostatically Embedded Generalized Molecular Fractionation with Conjugate Caps (EE-GMFCC) method to the prediction of excitation energies of PRs. Excitation energies of 10 variants of Blue Proteorhodopsin (BPR-PR105Q) in residue 105GLN were calculated with the EE-GMFCC method at the TD-B3LYP/6-31G* level. The calculated results show good correlation with the experimental values of absorption wavelengths, although the experimental wavelength range among these systems is less than 50 nm. The ensemble-averaged electric fields along the polyene chain of retinal correlated well with EE-GMFCC calculated excitation energies for these 10 PRs, suggesting that electrostatic interactions from nearby residues are responsible for the color tuning. We also utilized the GMFCC method to decompose the excitation energy contribution per residue surrounding the chromophore. Our results show that residues ASP97 and ASP227 have the largest contribution to the absorption spectral shift of PR among the nearby residues of retinal. This work demonstrates that the EE-GMFCC method can be applied to accurately predict the absorption spectral shifts for biomacromolecules.