Comparison between different surface treatment methods on shear bond strength of zirconia (in vitro study)

To compare the effect of Er:YAG Laser and Air particle abrasion (APA) surface treatments on shear bond strength of Y-TZP to composite resin cuboids in the presence and absence of primer application and salivary contamination. Seventy-two cuboidal shaped specimens 7x7x3 were prepared from Y-TZP using CADCAM, cleaned and sintered. Specimens were divided into 2 main groups (n=36) according to surface treatment method; Air particle abrasion (A) and laser (L). Each group was subdivided into 2 subgroups (N = 18) according to surface modification using primer; each subgroup was further divided into 2 subdivisions (N=9) according to the presence of salivary contamination; APC (Air particle abrasion, primer, contamination), AP (Air particle abrasion, primer), AC (Air particle abrasion, contamination), A (Air particle abrasion), LPC (Laser, primer, contamination), LP (Laser, primer), LC (Laser, contamination), L (Laser). Composite cuboids having dimensions of 6x6x3 were also fabricated using custom made plexi plates. Composite cuboids were cemented centrally to zirconia cuboids and light cured under 5 kg weight for 6 mins. Shear bond strength of specimens was measured utilizing universal testing machine at a crosshead speed of 0.5 mm/min. Failure loads were recorded in Newton. SBS was calculated according to equation: SBS (MPa) = load (N)/area(mm2). Viewing shear bond strength between studied groups, group APNC (484.02±85.02) showed higher mean value compared to ANPNC (122.09±55.80), also LNPNC (120.87±65.10) showed higher mean value in comparison to LPNC (170.78±53.22). APNC (484.02±85.02) and APC (592.22±189.65) showed higher mean values than LPNC (170.78±53.22) and LPC (3227.66±108.28) in sequence. APA showed higher SBS values than Er:YAG surface treatment. Primer showed better results than no primer coating. Artificial saliva contamination did not affect the SBS of zirconia compared with no contamination results

The Trembling Hand Approach to Automata in Iterated Games

We consider two state automata playing infinitely iterated two players, two strategies game, where each move can be mis-implemented (or mis-perceived) with a small error probability, and compute the payoff matrix by means of a perturbation approach. Keywords: Alternating Prisoner's Dilemma, Perturbed Payoff, Repeated Games, Simultaneous Prisoner's Dilemma

SHARM: Segmented Head Anatomical Reference Models

Reliable segmentation of anatomical tissues of human head is a major step in several clinical applications such as brain mapping, surgery planning and associated computational simulation studies. Segmentation is based on identifying different anatomical structures through labeling different tissues through medical imaging modalities. The segmentation of brain structures is commonly feasible with several remarkable contributions mainly for medical perspective; however, non-brain tissues are of less interest due to anatomical complexity and difficulties to be observed using standard medical imaging protocols. The lack of whole head segmentation methods and unavailability of large human head segmented datasets limiting the variability studies, especially in the computational evaluation of electrical brain stimulation (neuromodulation), human protection from electromagnetic field, and electroencephalography where non-brain tissues are of great importance. To fill this gap, this study provides an open-access Segmented Head Anatomical Reference Models (SHARM) that consists of 196 subjects. These models are segmented into 15 different tissues; skin, fat, muscle, skull cancellous bone, skull cortical bone, brain white matter, brain gray matter, cerebellum white matter, cerebellum gray matter, cerebrospinal fluid, dura, vitreous humor, lens, mucous tissue and blood vessels. The segmented head models are generated using open-access IXI MRI dataset through convolutional neural network structure named ForkNet+. Results indicate a high consistency in statistical characteristics of different tissue distribution in age scale with real measurements. SHARM is expected to be a useful benchmark not only for electromagnetic dosimetry studies but also for different human head segmentation applications

A COMPARISON BETWEEN THE EFFECT OF DIFFERENT PRESSURES OF AIR PARTICLE ABRASION BEFORE AND AFTER SINTERING WITH AND WITHOUT ZIRCONIA LINER ON BOND STRENGTH OF RESIN TO ZIRCONIA SURFACE

This study aimed to compare the effect of different pressures of air particle abrasion 2 and 4 bars before and after sintering with and without zirconia liner on SBS of resin to zirconia Surface. Materials and Methods: 54 zirconia cuboids 8×8×3 mm were milled and divided into 6 equal groups (N=9) according to surface treatment; sintered with ceramic liner application and 2 bars pressure (SL2) and with 4 bars pressure (SL4), sintered with no ceramic liner and 2 bars pressure (SN2) and 4 bars pressure (SN4), unsintered with no ceramic liner and 2 bars pressure (UN2) and 4 bars pressure (UN4). Specimens underwent thermocycling (1000 cycles) between 5 ̊ and 55 ̊ Celsius with dwell time of 10 seconds, and submitted to SBS test. Data was statistically analysed. Results: All 4 bars APA groups showed higher SBS than 2 bars groups with significant difference between SL4 group (4.7±2.07) and SL2 group (2.58±1.94). Groups with APA before sintering (12.42±2.56) showed significantly higher SBS than APA after sintering (6.35±3.7). SL2 group showed least SBS with significant difference (2.58±1.94) compared to UN2 (11.83±3.35) and SN2 (7.87±2.12). SL4 group (4.7±2.07) showed the least SBS compared to the UN4 (13±1.38), and SN4 (10.24±2.94) groups. Conclusion: It was found that APA of zirconia surface before sintering yielded superior performance than APA after sintering, also 4 bars APA pressure application showed higher SBS than 2 bars pressure, application and firing of ceramic liner onto zirconia surface didn’t enhance SBS

Influence of resin cement shade on the color and translucency of zirconia crowns

Zirconia crowns are highly attractive for clinicians, although have poor translucency when used as single restorations, in addition to unknown effect of resin cement shade on final cemented crown shade. This study aimed to assess effect of resin cement opacity on color replication potential of different zirconia frameworks with target tooth color, in addition to different zirconia crowns translucency evaluation. Twenty-four zirconia crown restorations were fabricated to restore single central maxillary incisor for 8 patients, divided into 3 groups according to color and type of zirconia used (white Zr core, colored Zr core and monolithic HT Zrcowns). Each group was further subdivided into 2 subgroups according to resin cement shade. Using Easyshade spectrophotometer, Delta E color difference was calculated between each crown parameters using 2 different resin luting cement shades and adjacent target tooth. Translucency parameters (TP) were tested for finished crowns. ?Es obtained were assessed based on ?Eof 1.6 which represented color difference that could not be detected by human eye and considered clinically acceptable. No statistically significant values were found between subgroups related to different resin cement shade. Translucency parameters showed statistically significant different values. Monolithic crowns showed highest translucency parameters followed by Zr crowns on white cores then Zr crowns on colored cores. Resin cement shade didn?t affect final color perception. Monolithic high translucency crowns usage gained advantages of high translucency and delamination prevention. Zirconia crowns could be cemented by opaque or transparent cement without affecting final color

Influence of core color on final shade reproduction of zirconia crown in single central incisor situation ? An in vivo study

A lot of shaded zirconia blocks are being introduced into the market. Their effect on the final shade of the restoration is yet uncertain. Twenty-four zirconia crowns were fabricated for 8 patients who needed to restore a single maxillary central incisor, and divided into 3 groups according to the color and type of the zirconia (Zr) used (white Zr core, colored Zr core, and monolithic high translucency (ht) Zr crowns). Using Easyshade spectrophotometer, delta E color difference was calculated between fabricated crown and adjacent tooth. The ?Es obtained were assessed based on 1.6 ?E which represented the color difference that could not be detected by the human eye and considered clinically acceptable. No statistically significant values were found between the 3 groups related to different Zr color and type. Within the limitations of this study, it could be concluded that the shade of the zirconia blank had no significant effect on the final color of the crown. This raises reasonable doubt about the necessity to use colored zirconia blanks or use of dip-in solutions. The clinical implications were that, there was no need to use colored zirconia cores to get more esthetically pleasing restorations with respect to color perception. The use of monolithic high translucent zirconia crowns gained the advantages of high translucency and color reproduction

Detection ofH.pyloricagAgene in patient's with gastroduodenal disease

Helicobacter pylori infection is common in the developing countries. The cagAgene is a marker of pathogenicity island (PAI) in H. pylori. The aim of this study was to determine the prevalence of cagAamong gastroduodenal disease (peptic ulcer and non-ulcer dyspepsia) in patients of Ramadi-city. A total of 81 gastric biopsy samples, gastric ulcer 10 (12.30% ) ,duodenal ulcer 18 (22.20% ) and non-ulcer dyspepsia 53 (65.40% ) by endoscopic examination . cagAgene of H. pylori was assessed using polymerase chain reaction (PCR). The cagAgene was detected by PCR technique in 3 from 10 biopsy specimens culture positive, urease test was showed 7(8.64%) patients, 2(2.5%) patients and 48(59.26%)patients after (2 hr, 6hr and 20 hr) respectively, ELISA positive result was showed 12(14.8%) patients.Urease test is easy test , inexpensive and can be use in endoscopy unit, but non-specific, culture is gold stander for detection of H.pylori, ELISA technique use for detection of anti-H.pyloriIgG , ELISA technique widly used for epidemiology studies. PCR assay used for detection of cagA gene.Using PCR to detect cagAgene from culture colony.The potential advantages of PCR include high specificity, quick results and the ability to type bacteria without the requirement for special transport conditions.

Optimizing Performance in Wireless Sensor Networks through a Multi-Objective Rendezvous Points Selection Algorithm

Wireless sensor networks (WSNs) play a vital role in modern research and applications due to their potential to gather data from various environments. Because sensor nodes (SNs) within WSNs have limited battery life, those in close proximity to the sink often experience rapid power depletion, leading to the emergence of hotspot issues. To address this, the concept of a mobile sink (MS) has emerged as a potential solution, effectively mitigating power usage in SNs and thereby extending the network’s overall lifespan. Furthermore, many sensor-based applications necessitate specific data collection timeframes, underscoring the necessity of effective strategies. Leveraging rendezvous points (RPs) to enhance network efficiency becomes imperative in enabling the MS to efficiently collect data from all SNs within designated time periods. A sophisticated cost function is employed to strategically determine RPs, considering multiple factors that influence the efficacy of each RP. This process culminates in the selection of RPs, optimizing for the longest path with minimal delays. Through the proposed hybrid mobile vehicle (HMV) method, compared against the prevailing MOOVor method, significant enhancements are observed in terms of sensor coverage and reduced hop count within the network