No abstract

This paper reports a fully implantable, MEMS-based, low-power, energy harvesting, next generation cochlear implant (CI). The implant includes multi-frequency piezoelectric transducers for sound detection and energy harvesting, rectification and signal conditioning electronics, and RF coil for fitting and external powering. These units have outstanding performances: multi-channel transducer can generate 50.7 mVpp (under 100 dB SPL) and recover the daily sound speech signals; signal conditioning IC consumes outstandingly low power (<500 µW) while converting outputs signals of the transducer to biphasic pulses; piezoelectric energy harvester has the highest power density (1.5 × 10 −3 W/cm 3 ) with generated 16.25 µW under 120 dB-A sound input; energy harvester IC, provides up to 500% more power compared to an ideal fullbridge rectifier.

The aim of this in vitro study was to evaluate the adhesion strength of two new fiber post systems (FiberSite™ Post and Cytec™ Blanco Post) cemented with two different adhesive resin cements (Panavia™ SA and Maxcem™ Elite). Root canals of sixty extracted human mandibular premolars were prepared using ProTaper Universal™ rotary files (Dentsply Sirona Endodontics, York, PA, USA). The root canals were irrigated with 5.25% sodium hypochlorite (NaOCl) during instrumentation. After root canal preparation, the canals were irrigated with 2 mL of 17% EDTA (1 min), followed by 2 mL of 5.25% (5 min) NaOCI, and 2 mL saline. The root canals were dried with paper points and divided randomly into two study groups (n = 30) according to the type of post system: Group 1, FiberSite™ Post (MegaDental, Partanna, Italy); and group 2, Cytec™ Blanco Post (Hahnenkratt, Königsbach-Stein, Germany), with one of the two adhesive resin cements: Subgroup A, Panavia™ SA Cement Plus Automix (Kuraray, Osaka, Japan); subgroup B, Maxcem™ Elite (Kerr, Orange, CA, USA). Following thermocycling, the adhesion strength was evaluated using the push-out adhesion (bond) strength test. Fractographic analysis was performed using stereomicroscope. The data were analyzed using two-way analysis of variance (p = 0.05). The adhesion strength values of both the posts were significantly higher when cemented with subgroup B (Maxcem™ Elite). The highest adhesion strength value was demonstrated by group 1B (FiberSite™ post cemented with Maxcem™ Elite cement). The type of post did not have a significant impact on the bond strength values for either cement material.

The aim of this study was to evaluate buccal bone thickness by cone beam computed tomography (CBCT) in patients in both genders and in different age groups. Materials and Methods: Our study included 186 anterior teeth and 62 patients with CBCT images. Buccal bone thickness was measured at the crest level, and at a distance 1 and 2 mm apical to the crest level. The t-test and ANOVA test were used in analyzing data. Results: It was found out that age and gender were not significantly associated with the buccal bone thickness of anterior teeth (p>0.05). The mean buccal bone thickness was the highest as 1.91 mm around the right canines and it was the lowest as 0.35 mm surrounding the right lateral incisor. Conclusions: Our study demonstrated that the mean buccal bone thickness increased towards the apical region for all three teeth types. CBCT precisely measures the maxillary bone thickness and may facilitate the planning process for placing implants and scheduling other types of surgeries correctly.

Background:The aim of this study was to compare the trabecular bone microstructure of the mandibular condyle in edentulous, unilateral edentulous (Kennedy Class II), and fully dentate patients. Materials and methods:The study used the cone-beam computed tomography (CBCT) images of 17 fully dentate (34 condyles), 16 edentulous (32 condyles), and 17 unilateral edentulous patients (34 condyles) aged 19 to 80 years. The trabecular bone microstructure of the mandibular condyle was evaluated on eight consecutive crosssectional images of these patients. In the microstructure analysis, structural model index (SMI), ellipsoid factor (EF), bone volume fraction (BV/TV), trabecular thickness (Tb.Th) and trabecular seperation (Tb.Sp) were measured. Results:There was no significant difference between the mean SMI, BV/TV, EF andTb.Th microstructure values of each group (p = 0.243, p = 0.095, p = 0.962, p = 0.095, respectively). However, there was significant difference in terms of mean Tb.Sp between the groups (p =0.021). The trabecular structure in all three groups was more rod-shaped. No correlation was found between age factor and microstructure values. Conclusions:Considering the in vivo microstructure analysis of CBCT images, it can be said that teeth loss does not have a significant effect on the microstructure parameters excluding Tb.sp of mandible condyles and does not affect mandibular condyle trabecular endurance.