Investigating the Poor Match among Different Precessing Gravitational Waveforms

The sixfold direct detection of gravitational waves opened the era of gravitational wave astronomy. All of these gravitational waves were emitted by black hole or neutron star binaries. The determination of the parameters characterizing compact binaries requires the accurate knowledge of waveforms. Three different waveforms (Spin Dominated, SpinTaylorT4 and Spinning Effective One Body fitted to Numerical Relativity, SEOBNR) are considered in the spin-aligned and precessing cases, in the parameter ranges where the larger spin dominates over the orbital angular momentum. The degeneracy in the parameter space of each waveform is analyzed, then the matches among the waveforms are investigated. Our results show that in the spin-aligned case only the inspiral Spin-dominated and SpinTaylorT4 waveforms agree well with each other. The highest matches of these with SEOBNR are at different parameters as compared to where SEOBNR shows the best match with itself, reflecting SEOBNR being full inspiral-merger-ringdown waveform, with coefficients fitted to numerical relativity, rather than arising from post-Newtonian (PN) calculations. In the precessing case, the matches between the pairs of all waveforms are significantly lower. We identify possible causes of this in (1) the implementation of the angular dynamics carried out at different levels of accuracy for different waveforms; (2) differences in the inclusiveness of the merger process and in the PN coefficients of the inspiral waveforms (Spin-Dominated, SpinTaylorT4) and the full SEOBNR waveform

Analog and digital modeling of sound and impaired periodontal supporting tissues during mechanical testing

Periodontitis is one of the most common conditions affecting oral health among adults, posing a great challenge for both patients and also for dentists aiming to treat this disease. In severe stages such deterioration of the supporting tissues, namely the periodontal ligaments and the bone, can occur, which will affect the biomechanical behavior and therefore the longevity and survival of the affected teeth. In order to be able to plan both periodontal and subsequent restorative treatment properly, valid modelling of the current clinical situation is advised. The aim of the present article is to comprehensively discuss possible analog and digital modeling methods of periodontally affected teeth and the periodontal structures surrounding them. Modelling possibilities can serve later as the basis of mechanical load, digital finite element studies, and also aid clinical treatment planning

Analog and digital modeling of sound and impaired periodontal supporting tissues during mechanical testing

Periodontitis is one of the most common conditions affecting oral health among adults, posing a great challenge for both patients and also for dentists aiming to treat this disease. In severe stages such deterioration of the supporting tissues, namely the periodontal ligaments and the bone, can occur, which will affect the biomechanical behavior and therefore the longevity and survival of the affected teeth. In order to be able to plan both periodontal and subsequent restorative treatment properly, valid modelling of the current clinical situation is advised. The aim of the present article is to comprehensively discuss possible analog and digital modeling methods of periodontally affected teeth and the periodontal structures surrounding them. Modelling possibilities can serve later as the basis of mechanical load, digital finite element studies, and also aid clinical treatment planning

Static and dynamic compression load tests of conically connected, screw fixed dental abutment: Implant assemblies

The basis of the long-term success of dental implants is the mechanical stability of the implant and the superstructure anchored in it. In order to investigate the mechanical behaviour of the conical connection in implant-abutment units, static and dynamic load tests were performed with different conical angles and various Grade 4-5 titanium implant materials. The assembled units were mounted in self-developed loading machine and in an Instron ElectroPuls E3000 fatigue machine. For static loading, the samples were loaded with a force from 0 N to 500 N in steps of 100 N. For dynamic loading, the samples were loaded for 30,000 cycles with a force of 250 ± 150 N. In case of static testing, the compression caused by the load was measured in both horizontal and vertical directions, while in the case of dynamic fatigue, only horizontal deformation was defined. In both cases, the drive-out (reverse) torque values of the fixing screws were determined after loading. No significant differences were found between the tested materials in the reverse torque after the static load, however, significant differences were shown with regards to the alterations in cone angle (p < 0.001). After dynamic loading, significant differences (p < 0.001) were also observed between the reverse torques of the fixing screw in different angles. The static and dynamic test results showed the same tendency: under the same load conditions, the conical angle value of the implant-abutment connection revealed significant differences in the loosening of the fixing screw. In summary, it is recommended to use higher conical angle connection to avoid larger deformations in lengths and diameters of the implant at the connection and essential torque reduction of the fixing screw. Our results may contribute to the understanding of the long-term success of dental implants

Static and dynamic compression load tests of conically connected, screw fixed dental abutment

The basis of the long-term success of dental implants is the mechanical stability of the implant and the superstructure anchored in it. In order to investigate the mechanical behaviour of the conical connection in implant-abutment units, static and dynamic load tests were performed with different conical angles and various Grade 4-5 titanium implant materials. The assembled units were mounted in self-developed loading machine and in an Instron ElectroPuls E3000 fatigue machine. For static loading, the samples were loaded with a force from 0 N to 500 N in steps of 100 N. For dynamic loading, the samples were loaded for 30,000 cycles with a force of 250 ± 150 N. In case of static testing, the compression caused by the load was measured in both horizontal and vertical directions, while in the case of dynamic fatigue, only horizontal deformation was defined. In both cases, the drive-out (reverse) torque values of the fixing screws were determined after loading. No significant differences were found between the tested materials in the reverse torque after the static load, however, significant differences were shown with regards to the alterations in cone angle (p < 0.001). After dynamic loading, significant differences (p < 0.001) were also observed between the reverse torques of the fixing screw in different angles. The static and dynamic test results showed the same tendency: under the same load conditions, the conical angle value of the implant-abutment connection revealed significant differences in the loosening of the fixing screw. In summary, it is recommended to use higher conical angle connection to avoid larger deformations in lengths and diameters of the implant at the connection and essential torque reduction of the fixing screw. Our results may contribute to the understanding of the long-term success of dental implants

Analog and digital modeling of sound and impaired periodontal supporting tissues during mechanical testing

Periodontitis is one of the most common conditions affecting oral health among adults, posing a great challenge for both patients and also for dentists aiming to treat this disease. In severe stages such deterioration of the supporting tissues, namely the periodontal ligaments and the bone, can occur, which will affect the biomechanical behavior and therefore the longevity and survival of the affected teeth. In order to be able to plan both periodontal and subsequent restorative treatment properly, valid modelling of the current clinical situation is advised. The aim of the present article is to comprehensively discuss possible analog and digital modeling methods of periodontally affected teeth and the periodontal structures surrounding them. Modelling possibilities can serve later as the basis of mechanical load, digital finite element studies, and also aid clinical treatment planning