scholarly journals Short-term immunosuppressive therapy does not affect the density of the pre-existing bone around titanium implants placed in rabbits

2003 ◽  
Vol 17 (4) ◽  
pp. 362-366 ◽  
Author(s):  
Poliana Mendes Duarte ◽  
Getúlio Rocha Nogueira Filho ◽  
Enilson Antônio Sallum ◽  
Antonio Wilson Sallum ◽  
Francisco Humberto Nociti Júnior
Keyword(s):  
Bone Density ◽  
Immunosuppressive Therapy ◽  
Negative Influence ◽  
Titanium Implants ◽  
Short Term ◽  
Implant Surface ◽  
Subcutaneous Injections ◽  
Significant Difference ◽  
Wide Zone ◽  
Lateral Area

The aim of this study was to evaluate the influence of the administration and withdrawal of cyclosporin A/nifedipine on the bone density in a lateral area adjacent to implants placed in rabbits. Two screw-type titanium implants were placed bilaterally in twenty-eight New Zealand rabbits. The animals were assigned to one of the following groups and received daily subcutaneous injections for 14 days: Groups A and C: vehicle (dimethyl sulfoxide); Groups B and D: CsA (10 mg/kg) plus nifedipine (50 mg/kg). The animals in Groups A and B were sacrificed 14 days postoperatively and, in Groups C and D, 42 days postoperatively. After sacrifice, the tibiae were removed and undecalcified sections were obtained. Bone density was obtained in a 500 mm-wide zone lateral to the implant surface. Intergroup analysis showed no significant difference (p > 0.05) in the degree of bone density between control and test groups either on day 14 or on day 42. Thus, it appears that a short-term immunosuppressive therapy may not present a negative influence on the density of the pre-existing bone around titanium implants placed in rabbits.

The red packet interaction and brand attitude in the brand communities on WeChat

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Guowei Zhu ◽  
Yaru Liu ◽  
Li Zhou
Keyword(s):  
Social Networking Sites ◽  
Time Frame ◽  
Negative Influence ◽  
Brand Attitude ◽  
Short Term ◽  
Content Type ◽  
Brand Communities ◽  
Significant Difference ◽  
Community Pressure

Purpose Monetary incentives have been widely adopted by brands to promote consumer engagement in their brand communities on social networking sites. This paper aims to explore how the interactions triggered by an emerging monetary incentive, red packets, affect consumers’ brand attitude in the context of WeChat brand groups (WCBGs). Design/methodology/approach According to whether brands ask for commercial returns from consumers, two types of interactions were identified, namely, exchange red packet interaction (ERPI) and communal red packet interaction (CRPI). The corresponding influences on brand attitude were examined in three experiments. Findings Compared to CRPIs, ERPIs elicit greater normative community pressure, inducing a less favorable brand attitude. Moreover, this impact is moderated by the time frame of brand communities. In the long-term WCBGs, a significant difference exists between ERPIs and CRPIs, while such difference attenuates or even disappears in short-term WCBGs. Practical implications When using red packets as an engagement strategy, brand managers should be alert to their potential negative influence. Specifically, in short-term brand communities, ERPIs enable managers to acquire commercial returns without hurting brand attitude. In long-term brand communities, managers are advised to implement CRPIs to foster a positive brand attitude. Originality/value This study investigates red packet interactions in brand communities, which have been widespread but unexplored. The results expand the literature by addressing the undermining effect of ERPI and the moderating effect of the time frame.

scholarly journals QCM Analysis for Two-Step Adsorption of Albumin and Fibronectin on Zirconia Surface

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Masatsugu Hirota ◽  
Tohru Hayakawa
Keyword(s):  
Protein Adsorption ◽  
Titanium Implants ◽  
Second Step ◽  
Material Surface ◽  
Clear Correlation ◽  
Attractive Alternative ◽  
Implant Surface ◽  
Living Body ◽  
Dental Implant Surface ◽  
Significant Difference

The adsorption of proteins on the dental implant surface is the first step in the key role of osseointegration. Many types of proteins exist in the living body and compete for adsorption on the material surface. As an implant material, partially stabilized zirconia (ZrO2) is currently an attractive alternative to titanium to overcome the shortcomings of titanium implants. In this study, we investigated the two-step adsorption of fibronectin (Fn) and bovine serum albumin (Alb) on the ZrO2 surface using a 27-MHz quartz crystal microbalance (QCM) method. A ZrO2 sensor was employed for the QCM measurements. Two-step adsorptions were performed as follows. (1) Fn-Alb series: first, the Fn solution was injected into the phosphate-buffered saline (PBS) solution, followed by the Alb solution. (2) Alb-Fn series: first, the Alb solution was injected, followed by the Fn solution. The decrease in frequency was monitored for 60 minutes after each protein injection. The adsorbed amounts of Fn or Alb were calculated by observing the decrease in frequency, and the apparent reaction rate, kobs, was obtained through the curve fitting of frequency shift against the adsorption time. No significant difference was observed in the adsorbed amounts of Fn and Alb between the Fn-Alb and Alb-Fn series ( P > 0.05 ). The kobs, rate of protein adsorption, in the second step was significantly slower than that in the first step for both Fn and Alb adsorption ( P < 0.05 ). There was no clear correlation between the amount of protein adsorbed on the ZrO2 sensor and the surface topography. It was concluded that the amount of protein adsorbed on the ZrO2 surface was not influenced by the two-step adsorption series, but the adsorption rate of proteins in the second step was affected by the first-step protein adsorption.

Influence of Surface Nano-Roughness on Osseointegration of Zirconia Implants in Rabbit Femur Heads Using Selective Infiltration Etching Technique

2013 ◽  
Vol 39 (5) ◽  
pp. 583-590 ◽  
Author(s):  
Moustafa N. Aboushelib ◽  
Noha A. Salem ◽  
Ahmed L. Abo Taleb ◽  
Naglaa M. Abd El Moniem
Keyword(s):  
Bone Density ◽  
White Male ◽  
Titanium Implants ◽  
Implant Surface ◽  
Etching Technique ◽  
Bone Implant ◽  
Bone Implant Contact ◽  
Zirconia Implants ◽  
Rabbit Femur ◽  
Zirconia Implant

This study evaluates osseous healing of selective infiltration-etched (SIE) zirconia implants compared to as-sintered zirconia and titanium implants. Twenty implants of each group were inserted in 40 adult New Zealand white male rabbits. After 4 and 6 weeks, bone blocks containing the implants were retrieved, sectioned, and processed to evaluate bone-implant contact (BIC) and peri-implant bone density. SIE zirconia implants had significantly higher BIC and marginally higher bone density. The results suggest that selective infiltration-etched zirconia implant surface may improve implant osseointegration.

scholarly journals Titanium Implants Coated with a Bifunctional Molecule with Antimicrobic Activity: A Rabbit Study

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3613 ◽  
Author(s):  
Antonio Scarano ◽  
Francesco Carinci ◽  
Tiziana Orsini ◽  
Luca Valbonetti ◽  
Erda Qorri ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Titanium Dioxide Nanoparticles ◽  
Titanium Implants ◽  
P Value ◽  
Implant Surface ◽  
Bone Implant ◽  
Bifunctional Molecule ◽  
Significant Difference ◽  
Bone Implant Contact ◽  
Antimicrobic Activity

Background: Various surface treatments have been tested for titanium implants aiming at increasing their surface biocompatibility and their biological characteristics, but also the efficiency of the implant surface will have to be improved to drastically decrease peri-implantite and mucosite. In fact, the peri-implantitis and peri-implant mucositis have a high incidence in clinical practice. The nanofabrication techniques that offer the possibility to achieve the implant surface that reduces bacterial colonization could influence the osteointegration. The aim of this research was to evaluate the bone response to titanium implants coated with a bifunctional molecule with antimicrobic activity consisting of a combination of silver ions covalently bound to titanium dioxide nanoparticles. Methods: A total of 36 implants were inserted into 18 older New Zealand white male rabbits. They had two different surfaces. The implants Control group was characterized by an acid-etched and sandblasted surface treatment, and the Test implants had an acid-etched and sandblasted surface coated with a silver ion covalently bound to titanium dioxide nanoparticles in the solution. Results: No statistically significant difference of the bone density was evidenced between Control and Test implants at two weeks (p-value = 0.623), four weeks (p-value = 0.339), and eight weeks (p-value = 0.461). Moreover, no statistically significant difference of the bone-implant contact percentage was evidenced between Control and Test implants at two weeks (p-value = 0.938), four weeks (p-value = 0.307), and eight weeks (p-value = 0.294). The effectiveness of the present investigation demonstrated no adverse effects on osseointegration, and no statistically significant differences were observed in the bone density and percentage of bone-implant contact between Test and Control implants at all the experimental time points (two, four, and eight weeks). Conclusions: Titanium implants coated with the silver-anatase solution bind very well to the bone and did not have an adverse effect on the bone tissue in a rabbit model. These facts suggest possible clinical applications for the silver composition.

scholarly journals Effect of Plasma of Argon Treated Implants on Bone Density: A Randomized, Controlled, Histomorphometric Study in Dogs

2018 ◽  
Vol 12 (1) ◽  
pp. 937-945
Author(s):  
Kazushige Tanaka ◽  
Erick Ricardo Silva ◽  
Shunsuke Kawakami ◽  
Luigi Canullo ◽  
Daniele Botticelli ◽  
...  
Keyword(s):  
Bone Density ◽  
Argon Plasma ◽  
Surface Characteristics ◽  
Titanium Implants ◽  
Treatment Control ◽  
Implant Surface ◽  
Randomized Controlled ◽  
Histomorphometric Study ◽  
Short Time ◽  
And Control

Background: Altering surface characteristics by increasing its energy and hydrophilicity will accelerate the interaction between cells and implant surface. Energy and hydrophilicity tend to disappear over a short time. The implant surface may be reactivated by the use of argon plasma Objective: To assess bone density at cleaned and activated titanium implants using argon plasma. Methods: Mandibular premolars and first molars were extracted bilaterally in eight Beagle dogs. After three months, four implants, two treated with argon plasma (test; plasma) and two left without treatment (control), were randomly installed in one side of the mandible. Abutments were applied on the implants and a non-submerged healing was allowed. After one month, the same surgical procedures were adopted on the opposite side of the mandible. The animals were euthanized after one month and ground sections representing the healing after 1 and 2 months were obtained for histological examination. Results: No statistically significant differences were found between test and control sites (p < 0.05). After 1 month of healing, new bone was 32.5 ± 12.2% and 33.8 ± 8.8% at the plasma and control sites, respectively. After 2 months, the respective values were 50.8 ± 21.5% and 47.6 ± 15.6%. Conclusion: The treatment of the implant surface with argon plasma did not have a significant effect on bone density around implants.

Bone Ingrowth Processes on Porous Metalic Implants

2009 ◽  
Vol 147-149 ◽  
pp. 776-781 ◽  
Author(s):  
Jarosław Sidun ◽  
Jan Ryszard Dąbrowski
Keyword(s):  
Bone Growth ◽  
Bone Ingrowth ◽  
Callus Formation ◽  
Tissue Growth ◽  
Titanium Implants ◽  
Osseous Tissue ◽  
Implant Surface ◽  
Growth Intensity ◽  
Significant Difference ◽  
Endosseous Implant

The surface of an endosseous implant has fundamental importance in forming mechanical and chemical connection with osseous tissue. One of the methods of enlarging area is using technology of powder metallurgy. The paper presents research regarding osteointegration of porous materials for implants made for Co-Cr-Mo and titanium with Bioglass type-S2. The research was made on the castrated goats averaging one year of age, from this oneself herds. Bone growth process on surfaces of implants made with additional bioglass was significantly intense. The amount of osseous tissue and the number of connection points are significantly increased. On surfaces of titanium implants few areas of stochastic callus formation were observed. In that case areas of preferential bone integration have uneven surface due to technological process. A significant difference appears in osseous tissue growth morphology on implant surface. In porous implants bone grows around the pores of an implant. The obtained results showed that porosity influences callus growth intensity beneficially on the implant structure. Use of bioglass increases bone growth intensity on implant surface.

Extrakorporális és intrakorporális anasztomózis rövid távú eredményeinek összehasonlítása malignus daganat miatt végzett laparoszkópos jobb oldali hemikolektómia esetén

2020 ◽  
Vol 73 (4) ◽  
pp. 148-152
Author(s):  
Kornél Vajda ◽  
László Sikorszki
Keyword(s):  
Length Of Stay ◽  
Gold Standard ◽  
Average Length ◽  
Colon Surgery ◽  
Right Hemicolectomy ◽  
Malignant Tumours ◽  
Short Term ◽  
Significant Difference ◽  
Laparoscopic Assisted ◽  
Laparoscopic Hemicolectomy

Összefoglaló. Bevezetés: A laparoszkópia térhódítása a jobb oldali colon műtéteknél is nyilvánvaló. Ma legtöbb helyen a laparoszkóposan asszisztált jobb oldali hemikolektómia extrakorporális anasztomózissal a gold standard. A morbiditás randomizált vizsgálatok alapján még 30% körüli. A technikai fejlődés lehetővé tette az intrakorporális anasztomózist. Célkitűzés: Retrospektív módon elemezni rosszindulatú jobb oldali vastagbéldaganat miatt végzett laparoszkópos hemikolektómiák rövid távú eredményeit a két módszer összehasonlításával. Eredmények: 2018. 01. 01. – 2019. 12. 31. között 184 jobb oldali hemikolektómiát végeztünk, ezek közül 122 történt malignus betegség miatt. 51 esetben nyitott és 71 esetben laparoszkópos műtét történt. 37 férfi (átlagéletkor: 70,59 év) és 34 nő (átlagéletkor: 72,14 év) volt. 50 esetben extrakorporális (EA) és 21 esetben pedig intrakorporális anasztomózist (IA) végeztünk. Az EA csoportban 18, míg az IA csoportban 3 szövődmény alakult ki 30 napon belül (p = 0,067). Az EA csoportból 3, az IA csoportból 1 beteget veszítettünk el 30 napon belül (p = 0,66). Az átlagos ápolási idő az EA csoportban 9,48 (5–32) nap, míg az IA csoportban 6,52 (4–19) nap volt (p = 0,001) a szövődményes esetekkel együtt. A szövődményes esetek nélkül az EA csoportban 6,35 (5–10) nap, az IA csoportban pedig 5,55 (4–8) napnak bizonyult (p = 0,09). A műtéti idő pedig az EA csoportban 147 (90–240) perc, az IA csoportban pedig 146,47 (90–265) perc volt (p = 0,11). Konklúzió: Az irodalommal összhangban azt találtuk, hogy IA esetén kevesebb a szövődmény, ezzel is összefüggésben rövidebb az átlagos ápolási idő, és a műtéti időt tekintve nincs szignifikáns különbség. Ezeket figyelembe véve az intrakorporális anasztomózis javasolható jobb oldali laparoszkópos hemikolektómia esetén. Summary. Introduction: Laparoscopy became evident for right-sided colon surgery too. Today the laparoscopic-assisted right-hemicolectomy is the gold standard with extracorporeal anastomosis. Morbidity according to randomized trials is still approximately 30%. The development of the surgical technique resulted in the creation of intracorporeal anastomosis. Our aim was to compare the short-term results of the two methods. Aim: To analyse the short-term results of right-sided hemicolectomy that were performed due to malignant tumours with the comparison of the two methods. Results: A cohort of 184 right-sided hemicolectomy were performed from 01.01.2018 to 31.12.2019 from which 122 were operated on because of a malignant disease. 51 open and 71 laparoscopic operations were performed. The average age of 37 men and 34 women were 70.59 and 72.14 years, respectively. 50 patients underwent extracorporeal (EA) anastomosis and 21 intracorporeal (IA) anastomosis. Within 30 days the number of complications were 18 in the EA group and 3 in the IA group (p = 0.067). 3 from the EA group and 1 from IA group died within 30 days (p = 0.66). The average length of stay were 9.48 days in the EA group and 6.52 days in the IA group together with the complicated cases (p = 0.001) while 6.35 days and 5.55 days without the complicated cases (p = 0.09). The average duration of operation was 147 minutes in the EA and 146.47 minutes in the IA group (p = 0.11). Conclusion: We found concordance with the literature that there are fewer complications in case of IA which might be related to shorter length of stay. There is no significant difference between the surgical times. Bearing these facts in mind, IA might be suggested for right- sided laparoscopic hemicolectomy.

Effect of short-term use of oral contraceptive pills on intraocular pressure

2020 ◽  
Vol 35 (3) ◽  
Author(s):  
Tayyaba Gul Malik ◽  
Hina Nadeem ◽  
Eiman Ayesha ◽  
Rabail Alam
Keyword(s):  
Oral Contraceptive ◽  
Childbearing Age ◽  
Short Term ◽  
Oral Contraceptive Pills ◽  
Contraceptive Pills ◽  
Time Period ◽  
Significant Difference ◽  
Group A ◽  
Group B ◽  
Short Time

Objective: To study the effect of short-term use of oral contraceptive pills on intra-ocular pressures of women of childbearing age.   Methods: It was a comparative observational study, conducted at Arif memorial teaching hospital and Allied hospital Faisalabad for a period of six months. Hundred female subjects were divided into two groups of 50 each. Group A, included females, who had been taking oral contraceptive pills (OCP) for more than 6 months and less than 36 months. Group B, included 50 age-matched controls, who had never used OCP. Ophthalmic and systemic history was taken. Careful Slit lamp examination was performed and intraocular pressures (IOP) were measured using Goldman Applanation tonometer. Fundus examination was done to rule out any posterior segment disease. After collection of data, we analyzed and compared the intra ocular pressures between the two groups by using ANOVA in SPSS version 21.   Results: Average duration of using OCP was 14.9 months. There was no significant difference of Cup to Disc ratios between the two groups (p= 0.109). However, significant difference was noted between the IOP of OCP group and controls. (p=0.000). Conclusion: OCP significantly increase IOP even when used for short time period.

T1 Relaxation Time of Achilles Tendon at 3 Tesla with Special Reference to Relevant Clinical Score: A Preliminary Study

2020 ◽  
Vol 16 (2) ◽  
pp. 164-173
Author(s):  
Zeineb Tbini ◽  
Mokhtar Mars ◽  
Mouna Bouaziz
Keyword(s):  
Relaxation Time ◽  
Achilles Tendon ◽  
Clinical Score ◽  
3 Tesla ◽  
Acquisition Time ◽  
Short Term ◽  
T1 Relaxation Time ◽  
T1 Relaxation ◽  
Spin Echo Sequence ◽  
Significant Difference

Purpose: The purpose of this study was to investigate T1 relaxation time of the human Achilles tendon, to test its short-term repeatability as well as the minimal detectable change, and to assess the extent that correlate with clinical symptoms. Methods: Twenty asymptomatic volunteers and eighteen patients with clinically and sonographically confirmed tendinopathy were scanned for ankle using a 3 Tesla (T) MR scanner. T1 maps were calculated from a variable flip angle gradient echo Ultra-short echo time sequence (VFA-GE UTE) and inversion recovery spin echo sequence (IR-SE) using a self-developed matlab algorithm in three regions of interest of Achilles Tendon (AT). Signal to Noise Ratio (SNR) between the two sequences was evaluated. INTRA-class Correlation Coefficient (ICC), Coefficient of Variation (CV) and the Least Significant Change (LSC) were calculated, to test short-term repeatability of T1. Subjects were assessed by the VISA-A clinical score. P values less than 0.005 were considered statistically significant. Results: Mean T1 values were 427.09 ± 53.37 ms and 528.70 ± 103.50 ms using IR-SE sequence and 575.43 ± 110.60 ms and 875.81 ± 425.77 ms with VFA-GE UTE sequence in the whole AT for volunteers and patients, respectively. : T1 values showed a significant difference between volunteers and patients (P=0.001). Regional variation of T1 in healthy and tendinopathic AT were greater for VFA-GE UTE sequence than for IR-SE sequence. VFA-GE UTE sequence showed clearly higher SNR compared to IR-SE sequence. Short-term repeatability of T1 values for volunteers showed an LSC of 22% and 14% for IR-SE sequence and VFA-GE UTE sequence, respectively. For patients, LSC was 14% and 5% for IR-SE sequence and VFA-GE UTE sequence, respectively. There was no correlation between T1 and VISA-A clinical score (p>0.005). Conclusion: VFA-GE UTE sequence used for T1 mapping calculation demonstrated short acquisition time and clearly high SNR. Results revealed that T1 relaxation time can be used as a biomarker to differentiate between healthy and pathologic Achilles tendon. However, T1 showed no correlation with the VISA-A clinical score.

scholarly journals Optimizing Manufacturing and Osseointegration of Ti6Al4V Implants through Precision Casting and Calcium and Phosphorus Ion Implantation? In Vivo Results of a Large-Scale Animal Trial

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1670 ◽  
Author(s):  
Wölfle-Roos JV ◽  
Katmer Amet B ◽  
Fiedler J ◽  
Michels H ◽  
Kappelt G ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Large Scale ◽  
In Vivo Studies ◽  
Control Group ◽  
Implant Surface ◽  
Precision Casting ◽  
Pull Out ◽  
Significant Difference ◽  
Calcium And Phosphorus

Background: Uncemented implants are still associated with several major challenges, especially with regard to their manufacturing and their osseointegration. In this study, a novel manufacturing technique—an optimized form of precision casting—and a novel surface modification to promote osseointegration—calcium and phosphorus ion implantation into the implant surface—were tested in vivo. Methods: Cylindrical Ti6Al4V implants were inserted bilaterally into the tibia of 110 rats. We compared two generations of cast Ti6Al4V implants (CAST 1st GEN, n = 22, and CAST 2nd GEN, n = 22) as well as cast 2nd GEN Ti6Al4V implants with calcium (CAST + CA, n = 22) and phosphorus (CAST + P, n = 22) ion implantation to standard machined Ti6Al4V implants (control, n = 22). After 4 and 12 weeks, maximal pull-out force and bone-to-implant contact rate (BIC) were measured and compared between all five groups. Results: There was no significant difference between all five groups after 4 weeks or 12 weeks with regard to pull-out force (p > 0.05, Kruskal Wallis test). Histomorphometric analysis showed no significant difference of BIC after 4 weeks (p > 0.05, Kruskal–Wallis test), whereas there was a trend towards a higher BIC in the CAST + P group (54.8% ± 15.2%), especially compared to the control group (38.6% ± 12.8%) after 12 weeks (p = 0.053, Kruskal–Wallis test). Conclusion: In this study, we found no indication of inferiority of Ti6Al4V implants cast with the optimized centrifugal precision casting technique of the second generation compared to standard Ti6Al4V implants. As the employed manufacturing process holds considerable economic potential, mainly due to a significantly decreased material demand per implant by casting near net-shape instead of milling away most of the starting ingot, its application in manufacturing uncemented implants seems promising. However, no significant advantages of calcium or phosphorus ion implantation could be observed in this study. Due to the promising results of ion implantation in previous in vitro and in vivo studies, further in vivo studies with different ion implantation conditions should be considered.

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