Clinical Evaluation of a New Electronic Periodontal Probe: A Randomized Controlled Clinical Trial

Precise measurements of periodontal parameters (such as pocket depths: PPD, gingival margins: GM) are important for diagnosis of periodontal disease and its treatment. Most examiners use manual millimeter-scaled probes, dependent on adequate pressure and correct readouts. Electronic probes aim to objectify and facilitate the diagnostic process. This randomized controlled trial compared measurements of a standard manual (MP) with those of an electronic pressure-sensitive periodontal probe (EP) and its influence on patients’ acceptance and practicability. In 20 patients (2436 measuring points) PPD and GM were measured either with MP or EP by professionals with different levels of experience: dentist (10 patients), 7th and 10th semester dental students (5 patients each). Time needed was measured in minutes and patients’ subjective pain was evaluated by visual analogue scale. Differences were analyzed using the generalized estimating equations approach (GEE) and paired Wilcoxon tests. Mean PPD varied with ΔPPD 0.38 mm between both probes, which was significant (p < 0.001), but GM did not (ΔREC 0.07 mm, p = 0.197). There was a statistically significant correlation of both probes (Spearman’s rho correlation coefficient GM: 0.674, PPD: 0.685). Differences can be considered robust (no deviation in either direction). The comparison of time needed and pain sensitivity did not result in statistically significant differences (p > 0.05).

EVALUATION OF AN ELECTRONIC PERIODONTAL PROBE VERSUS A MANUAL PROBE IN THE PERIODONTAL DIAGNOSIS OF CHILDREN AGED 12-14 YEARS

Objective: The purpose of the trial is to comparatively analyze an electronic, pressure-calibrated probe third generation Parometer (Orange) and a standard, manual measurement probe WHO 621 (C type) in the context of taking periodontal variables when assessing periodontal status in childhood. Materials and methods: The subject of the study were 28 children aged between 12 and 14 years (12 boys and 16 girls). All patients were clinically examined, and the data were recorded on a specially prepared card. The recorded clinical variables contain: Assessment of oral hygiene habits (type of toothbrush, frequency of brushing); OHI as per Green Vermillion; Registration of dental status; Depth of gingival sulcus (on all teeth) with both types of probes; BOP (bleeding on probing), percentage of bleeding units with both types of probes; Taking into account the complete time needed to take the findings and the sensation of pain experienced by a digital rank scale during probing. Results and conclusion: The average depth of gingival sulcus measured with a mechanical periodontal probe was 1.62 mm, and with an electronic one - 1.38 mm (p <0.05). Values ​​for BOP with both types of probes showed an average of 0.30 ± 0.29, which is 30% of all bleeding units examined (p> 0.05). The time for recording the periodontal indices with both probes is, on average, 10 minutes. In both probes, the discomfort of about grade 4 was observed according to the ranking scale used to read sensitivity (p <0.05). There is a more pronounced sensitivity when using an electronic periodontal probe.

STABILITY OF ALFVEN WINGS IN HMHD

A conducting source moving uniformly through a magnetized plasma generates, among a variety of perturbations,Alfvén waves. Alfvén waves can build up structures in the plasma called Alfvén wings. The wings have been detec-ted and measured in many solar system bodies, and their existence have been theoretically proved also. Under certainconditions, Hall and electronic pressure must be taken into account in the Ohm’s law and so one gets Hall Magne-tohydrodynamics (HMHD). In spite of Sallago and Platzeck have shown the existence of Alfvén wings in HMHD, theirstability under such conditions remains to be studied. The aim of this paper is to analyze the stability of an Alfvén wing,in the presence of an incompressible perturbation that has the same symmetry than the structure and polarization, inHMHD. Palumbo has developed an analytical method for the study of the stability of static structures with a symmetryin magnetized plasmas, in the presence of incompressible perturbations with the same symmetry than the structure.Since Alfvén wings are stationary structures, Sallago and Platzeck have shown the stability of such Alfvén wings in MHD conditions by extending Palumbo’s method. In the present paper this method is extended for Alfvén wings in HMHD conditions, and one concludes that in the presence of this kind of perturbations they are stable.

Effect of posterior cruciate ligament recession on knee joint pressure and joint space measured by an electronic pressure sensor during total knee arthroplasty

Purpose: The purpose of this study was to evaluate the change in posterior cruciate ligament (PCL) tension by directly measuring the pressure changes in the knee joint when the ligament was released or resected during total knee arthroplasty (TKA).Methods: We prospectively analysed 22 patients who underwent primary TKA (28 knees) between October 2019 and January 2020. The pressure changes in the medial and lateral compartment were measured with an electronic pressure sensor with PCL retention (at 0°, 45°, 90° and 120° of flexion), tibial recession and PCL resection, and changes in the knee joint space were measured.Results: At 0°, 45°, 90° and 120° of flexion, the total pressure in the knee joint after tibial recession of the PCL was significantly higher than with PCL resection, and higher than PCL recession, but only at 120°. Recession or resection of the PCL affected knee joint extension, and the medial/lateral pressure in the knee joint decreased. Pressure in the lateral compartment showed no significant change, while pressure in the medial compartment decreased significantly during knee flexion, which also led to a change in the ratios of the medial and lateral pressures in the knee joint. After resecting the PCL, the mean flexion and extension gaps increased by 0.64 mm and 0.46 mm, respectively.Conclusion: Tibial recession of the PCL can release the PCL while retaining some PCL function. PCL release affects both the flexion and extension gaps, and more cases will increase the flexion gap.

Variations of quantum electronic pressure under the external compression in crystals with halogen bonds assembled in Cl3-, Br3-, I3-synthons

The inner-crystal quantum electronic pressure was estimated for unstrained C6Cl6, C6Br6, and C6I6 crystals and for those under external compression simulated from 1 to 20 GPa. The changes in its distribution were analyzed for the main structural elements in considered crystals: for triangles of the typical halogen bonds assembled in Hal3-synthons, where Hal = Cl, Br, I; for Hal...Hal stacking interactions, as well as for covalent bonds. Under simulated external compression, the quantum electronic pressure in the intermolecular space reduces as the electron density increases, indicating spatial areas of relatively less crystal resistance to external compression. The most compliant C6Cl6 crystal shows the largest changes of quantum electronic pressure in the centre of Cl3-synthon while the deformation of rigid I3-synthon under external compression depends only on the features of I...I halogen bonds.

Antarctic subglacial drill rig. Part II: Ice and Bedrock Electromechanical Drill (IBED)

A new, modified version of the cable-suspended Ice and Bedrock Electromechanical Drill (IBED) was designed for drilling in firn, ice, debris-rich ice and rock. The upper part of the drill is almost the same for all drill variants and comprises four sections: cable termination, a slip-ring section, an antitorque system and an electronic pressure chamber. The lower part of the IBED comprises an auger core barrel, reamers, a core barrel for ice/debris-ice drilling and a conventional geological single-tube core barrel or custom-made double-tube core barrel. First, the short and full-scale field versions of the IBED were tested at an outdoor testing stand and a testing facility with a 12.5 m-deep ice well. Then, in the 2018–2019 summer season, the IBED was tested in the field at a site ~12 km south of Zhongshan Station, East Antarctica, and a ~6 cm bedrock core was recovered from a 198 m-deep borehole. A total of 18 d was required to penetrate the ice sheet. The retrieved core samples of blue ice, basal ice and bedrock provided valuable information regarding the Earth's paleo-environment.