Biomechanical changes of freezer-storaged and decellularized pig tracheal scaffoldings

Background As an excellent xenotransplant, the pig trachea can be decellularized and cryopreserved to reduce its immunogenicity. However, few reports are found on the changes of its mechanical properties after cryopreservation and decellularization. Objective To evaluate the structure and biomechanical properties in pig tracheal scaffolds resulting from decellularized and cryopreserved. Material and methods Twenty-five pig tracheal segments were separated into five groups: untreated (group A), only decellularized (group B), only cryopreserved (group C), decellularized after cryopreserved (group D) and cryopreserved after decellularized (group E). Tracheal segments were subjected to uniaxial tension or compression using a universal testing machine to determine structural biomechanical changes. Results It showed that there was no statistically significant difference in the tensile strength of the trachea in each group. The compressive strength of group B, C and D were same as the group A ( P > 0.05), while the group E was lower than that of the group A ( P < 0.05). Conclusions and significance: The histological examination of the decellularization after cryopreservation shows that the removal of epithelial cells and submucosal cells is more thorough, and the biomechanical structure of the trachea is better preserved. This proved to be a new method to prepare xenotransplantation of trachea graft.

Download Full-text

Evaluation of crosshead speed influence on shear bond strength test

Brazilian Dental Science ◽

10.14295/bds.2014.v17i3.1003 ◽

2014 ◽

Vol 17 (3) ◽

pp. 50

Author(s):

Celina Wanderley de Abreu ◽

Gilberto Duarte Filho ◽

Alberto Noriyuki Kojima ◽

Renato Morales Jóias ◽

Alfredo Mikail Melo Mesquita

Keyword(s):

Bond Strength ◽

Shear Bond Strength ◽

Testing Machine ◽

Font Size ◽

Universal Testing ◽

Significant Difference ◽

Group A ◽

The Mean ◽

Group B ◽

Group D

The objective of this study was to evaluate the influence of different speeds using the piston device in the shear bond strength. 48 cylinders of composed resin had been confectioned (Solidex),and were divided randomly in four groups (n=12). The specimens were adapted to the device for the shear bond strenth test and were taken to an universal testing machine with a load cell of 1000Kg. The test were carried through with four different speeds: group A: 0,5; group B: 1,0; group C: 1,5 and group D: 2,0mm/min. The mean and standard deviations, in Kgf, were: A - 66,31(10,24); B - 64,53 (20,40); C - 75,23 (11,84) and D - 66,62 (13,81). The data were submitted to ANOVA (p=0,13). The results indicated that it did not have statistical significant difference between the groups A, B, C and D concluding that the speed in this type of test, with this device, can be varied without modify results.

Download Full-text

Load-to-fracture Value of Different All-ceramic Crown Systems

The Journal of Contemporary Dental Practice ◽

10.5005/jcdp-6-4-54 ◽

2005 ◽

Vol 6 (4) ◽

pp. 54-63 ◽

Cited By ~ 14

Author(s):

Mark David Snyder ◽

Kyle Douglas Hogg

Keyword(s):

Static Load ◽

Testing Machine ◽

P Value ◽

Universal Testing ◽

All Ceramic ◽

Group A ◽

Group B ◽

Ceramic Crown ◽

Group D ◽

Adhesive Cement

Abstract Objectives The purpose was to investigate the potential difference in the load-to-fracture values of several all-ceramic crown systems. Five different coping-reinforced all-ceramic crown systems were selected. Ten crowns from each system were fabricated and luted to standardized titanium dies. Methods The study consisted of five groups of ten samples each, all luted using G.C. Link Max resin adhesive cement. Group A: IPS Eris®, Group B: Cerac® In-lab Alumina coping, Group C: Cerac® In- lab Zirconia coping, Group D: Procera® AllCeram Alumina coping, and Group E: Procera® Zirconia coping. Following cementation, the samples were placed under a 5 Kg static load for 10 minutes insuring proper seating and stored in 100% humidity for one week. All samples were visually inspected prior to testing and were loaded to fracture at the rate of 0.5 mm/min using a universal-testing machine. Results Group A = 321.49 KgF ± 113.69 (S.D.), Group B = 288.63 ± 102.82 (S.D.), Group C = 266.58 ± 69.17 (S.D.), Group D = 295.49 ± 80.54 (S.D.), and Group E = 420.37 ± 82.45 (S.D.). The data were analyzed using an unpaired t-test; this indicated a statistical difference between group E and all of the others (P-value ≤0.039). Conclusions We concluded under these conditions, the Procera® Zirconia crown system has significant higher load-to-fracture value than several other all-ceramic crown systems. Citation Snyder MD, Hogg KD. Load-to-fracture Value of Different All-ceramic Crown Systems. J Contemp Dent Pract 2005 November;(6)4:054-063.

Download Full-text

Assessing Fracture Resistance of Restored Premolars with Novel Composite Materials: An In Vitro Study

International Journal of Dentistry ◽

10.1155/2021/5512708 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Zahraa Abdulaali Al-Ibraheemi ◽

Huda Abbas Abdullah ◽

Nada Abdlameer Jawad ◽

Julfikar Haider

Keyword(s):

Fracture Resistance ◽

Testing Machine ◽

In Vitro Study ◽

Vitro Study ◽

Resistance Testing ◽

Significant Difference ◽

Group A ◽

Group B ◽

Group D

During restorative treatment, premolars restored with resin filling materials using the conventional incremental-fill technique take longer restoration time and undermine the integrity of the tooth. The aim of this study was to assess fracture resistance of premolars restored by various types of novel bulk-fill composite resin materials. Forty-eight (n = 48) freshly extracted sound maxillary first premolars were used in this in vitro study. The teeth were divided into six groups, each having 8 specimens. Group A (positive control) was allocated for the intact teeth. For specimens in Groups B to F, a large cavity (Class-II MOD) was prepared with a standardized dimension of cavity (3 mm depth on the pulpal floor, 4 mm at the gingival seat, and 3 mm cavity width). Group B represented prepared teeth without any restoration. Group C, Group D, Group E, and Group F were restored with Tetric EvoCeram® incremental-fill (conventional), Beautifil bulk-fill, Filtek posterior bulk-fill, and SonicFill 2 bulk-fill restorative materials, respectively. All samples were finished and polished with an enhanced finishing kit and stored in distilled water for a month before the fracture resistance testing. All the samples were exposed to the axial loading (the speed of crosshead was 1 mm/min) in a computer-controlled universal testing machine (LARYEE, China) via a steel bar (6 mm in diameter) and the maximum applied force in Newton was recorded as the fracture resistance. One-way analysis of variance (SPSS 21) was used to compare the fracture resistance within the groups, and Tukey’s post hoc test was used to determine the difference between the groups. The lowest value of fracture resistance was recorded for Group B, and the highest value was recorded for Group A followed by the values of Group D, Group C, Group F, and Group E. One-way ANOVA revealed a statistically significant difference between the groups ( P < 0.05 ). Nonsignificant difference was found between the premolars restored by bulk-fill and conventional composites. Among the bulk-fill restored specimens, Beautifil restorative demonstrated significantly higher fracture resistance in comparison with the other two bulk-fill restored specimen groups (SonicFill 2 and Filtek). Bulk-fill composite such as Beautifil could be an alternative option to conventional incremental-fill composite for premolar restoration.

Download Full-text

The Role of Obesity in Predicting the Clinical Outcomes of COVID-19

Obesity Facts ◽

10.1159/000517180 ◽

2021 ◽

pp. 1-9

Author(s):

Serdar Sahin ◽

Havva Sezer ◽

Ebru Cicek ◽

Yeliz Yagız Ozogul ◽

Murat Yildirim ◽

...

Keyword(s):

Clinical Outcomes ◽

Health Care Providers ◽

Study Groups ◽

Normal Weight ◽

Overweight And Obesity ◽

Care Providers ◽

Significant Difference ◽

Group A ◽

Group B ◽

Group D

Introduction: The aim of this was to describe the predictors of mortality related to COVID-19 infection and to evaluate the association between overweight, obesity, and clinical outcomes of COVID-19. Methods: We included the patients >18 years of age, with at least one positive SARS-CoV-2 reverse transcriptase-polymerase chain reaction. Patients were grouped according to body mass index values as normal weight <25 kg/m2 (Group A), overweight from 25 to <30 kg/m2 (Group B), Class I obesity 30 to <35 kg/m2 (Group C), and ≥35 kg/m2 (Group D). Mortality, clinical outcomes, laboratory parameters, and comorbidities were compared among 4 groups. Results: There was no significant difference among study groups in terms of mortality. Noninvasive mechanical ventilation requirement was higher in group B and D than group A, while it was higher in Group D than Group C (Group B vs. Group A [p = 0.017], Group D vs. Group A [p = 0.001], and Group D vs. Group C [p = 0.016]). Lung involvement was less common in Group A, and presence of hypoxia was more common in Group D (Group B vs. Group A [p = 0.025], Group D vs. Group A [p < 0.001], Group D vs. Group B [p = 0.006], and Group D vs. Group C [p = 0.014]). The hospitalization rate was lower in Group A than in the other groups; in addition, patients in Group D have the highest rate of hospitalization (Group B vs. Group A [p < 0.001], Group C vs. Group A [p < 0.001], Group D vs. Group A [p < 0.001], Group D vs. Group B [p < 0.001], and Group D vs. Group C [p = 0.010]). Conclusion: COVID-19 patients with overweight and obesity presented with more severe clinical findings. Health-care providers should take into account that people living with overweight and obesity are at higher risk for COVID-19 and its complications.

Download Full-text

Prophylactic temporary abdominal aortic balloon occlusion for patients with pernicious placenta previa: a retrospective study

BMC Anesthesiology ◽

10.1186/s12871-021-01354-1 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Fei Huo ◽

Hansheng Liang ◽

Yi Feng

Keyword(s):

Placenta Previa ◽

Balloon Occlusion ◽

Artery Embolism ◽

Abdominal Aortic ◽

Significant Difference ◽

Group A ◽

Group B ◽

Clinical Records ◽

Group D ◽

Central Placenta Previa

Abstract Background Pernicious placenta previa (PPP) can increase the risk of perioperative complications. During caesarean section in patients with adherent placenta, intraoperative blood loss, hysterectomy rate and transfusion could be reduced by interventional methods. Our study aimed to investigate the influence of maternal hemodynamics control and neonatal outcomes of prophylactic temporary abdominal aortic balloon (PTAAB) occlusion for patients with pernicious placenta previa. Methods This was a retrospective study using data from the Peking University People’s Hospital from January 2014 through January 2020. Clinical records of pregnant women undergoing cesarean section were collected. Patients were divided into two groups: treatment with PTAAB placement (group A) and no balloon placement (group B). Group A was further broken down into two groups: prophylactic placement (Group C) and balloon occlusion (group D). Results Clinical records of 33 cases from 5205 pregnant women underwent cesarean section were collected. The number of groups A, B, C, and D were 17, 16, 5 and 12.We found that a significant difference in the post-operative uterine artery embolism rates between group A and group B (0% vs.31.3%, p = 0.018). There was a significant difference in the Apgar scores at first minute between group A and group B (8.94 ± 1.43 vs 9.81 ± 0.75,p = 0.037),and the same significant difference between two groups in the pre-operative central placenta previa (29.4% vs. 0%,p = 0.044), complete placenta previa (58.8% vs 18.8%, p = 0.032),placenta implantation (76.5% vs 31.3%, p = 0.015). We could also observe the significant difference in the amount of blood cell (2.80 ± 2.68vs.10.66 ± 11.97, p = 0.038) and blood plasma transfusion (280.00 ± 268.32 vs. 1033.33 ± 1098.20, p = 0.044) between group C and group D. The significant differences in the preoperative vaginal bleeding conditions (0% vs 75%, p = 0.009), the intraoperative application rates of vasopressors (0% vs. 58.3%, p = 0.044) and the postoperative ICU (intensive care unit) admission rates (0% vs. 58.3%, p = 0.044) were also kept. Conclusions PTAAB occlusion could be useful in reducing the rate of post-operative uterine artery embolism and the amount of transfusion, and be useful in coping with patients with preoperative vaginal bleeding conditions, so as to reduce the rate of intraoperative applications of vasopressors and the postoperative ICU (intensive care unit) admission. In PPP patients with placenta implantation, central placenta previa and complete placenta previa, we advocate the utilization of prophylactic temporary abdominal aortic balloon placement.

Download Full-text

Frictional Characteristics of the Newer Low-friction Elastomeric Ligatures

Journal of Contemporary Dentistry ◽

10.5005/jp-journals-10031-1137 ◽

2016 ◽

Vol 6 (1) ◽

pp. 19-23

Author(s):

Amol Mhatre ◽

VK Ravindranath ◽

Sachin Doshi ◽

Girish Karandikar ◽

PS Vivek

Keyword(s):

Testing Machine ◽

Frictional Resistance ◽

Minimal Amount ◽

New Delhi ◽

Low Friction ◽

Significant Difference ◽

Group A ◽

Group B ◽

New Generation

ABSTRACT Aim The aim of this in vitro study was to investigate the efficiency of the new generation of elastomeric ligatures with innovative designs (SlideTM and AlastiKTM Easy-to-Tie) in reducing frictional resistance (FR) during sliding mechanics as compared with conventional ligatures. Materials and Methods Sixty ligature samples divided into four groups were used for the study. Group A: QuiK-StiK™ (3M Unitek, Monrovia, CA, USA), Group B: AlastiK™ Easy-to-Tie (3M Unitek, Monrovia, CA, USA), Group C: Slide™ (Leone, Firenze, Italy), and Group D: SS ligatures 0.010” (Libral Traders, New Delhi, India). Universal Testing Machine, Instron was used for measuring FR at the bracket-wire interface. Results There was statistically significant difference in FR among all the four groups of ligatures tested (p < 0.001). Slide ligatures produced the least amount of FR followed by SS ligatures, Easy-to-Tie, and QuiK-StiK in the increasing order of the FR values registered. Conclusion SlideTM ligatures may represent a valid alternative to passive self-ligating brackets when minimal amount of friction is desired. Angulation introduced into the elastomeric ligatures reduces the friction in comparison to conventional elastomeric ligatures. How to cite this article Vivek PS, Ravindranath VK, Karandikar G, Doshi S, Mhatre A, Sonawane M. Frictional Characteristics of the Newer Low-friction Elastomeric Ligatures. J Contemp Dent 2016;6(1):19-23.

Download Full-text

Effect of Delayed Light-Curing Through a Zirconia Disc on Microhardness and Fracture Toughness of Two Types of Dual-Cure Cement

Journal of Dentistry of Tehran University of Medical Sciences ◽

10.18502/jdt.v15i6.326 ◽

2019 ◽

Author(s):

Pouran Samimi ◽

Sara Kaveh ◽

Maryam Khoroushi

Keyword(s):

Fracture Toughness ◽

Delay Group ◽

Fracture Toughness Test ◽

Irradiation Group ◽

Significant Difference ◽

Group A ◽

Light Curing ◽

Group B ◽

Post Hoc ◽

Group D

Objectives: Photopolymerization immediately sets dual-cure cements and prevents the continuation of chemical polymerization. Delayed light-curing allows the chemical process to continue up to the point before starting irradiation; however, there is a controversy in this respect. The present study evaluates the effect of delayed light-curing through a zirconia disc on the microhardness and fracture toughness (KIC) of two types of dual-cure cement. Materials and Methods: Samples measuring 25×5×3 mm3 were prepared for fracture toughness test, and discs measuring 5 mm in diameter and 3 mm in thickness were prepared for microhardness test using Bifix and BisCem cements. Light-curing protocols were as follows: immediate light-curing (group A), a 2-minute delay (group B), a 5-minute delay (group C), direct irradiation (group D), and no irradiation (group E). In groups A to C, light-curing was carried out through a zirconia disc. Data were analyzed by two-way and one-way analysis of variance (ANOVA), post-hoc Tukey's test, and Kruskal-Wallis test at 95% confidence interval. Results: There was a significant difference in the microhardness of the cements (P=0.00). Delayed light-curing had no effect on microhardness (P=0.080). The microhardness of BisCem in group E was significantly lower than that in group D (P=0.015). The fracture toughness of Bifix in groups B and C was significantly different than that in group E and BisCem groups. Conclusions: Under the limitations of our study, delayed light-curing had different effects on microhardness and fracture toughness. Differences in light-curing protocols resulted in different effects based on the cement type. Light-curing is recommended to achieve optimal mechanical properties.

Download Full-text

The Efficacy and Safety of Nabufen and Sufentanil in the Prevention of Visceral Pain After Gynecological Laparoscopic Surgery: A Randomised Controlled Trial

10.21203/rs.3.rs-125287/v1 ◽

2020 ◽

Author(s):

Xiaoxia Gu ◽

Jingjing Wang ◽

Huihua Liao ◽

Jian Mo ◽

Weiming Huang ◽

...

Keyword(s):

Laparoscopic Surgery ◽

Adverse Reactions ◽

Visceral Pain ◽

Sedation Score ◽

Efficacy And Safety ◽

Significant Difference ◽

Group A ◽

Group B ◽

Group D ◽

Ramsay Sedation Score

Abstract Background: To compare the efficacy and safety of different compatibility schemes in the prevention of visceral pain after gynecological laparoscopic surgery. Methods: from April 2019 to April 2020, patients undergoing elective gynecological laparoscopic surgery in our hospital were randomly divided into four groups: group A: sufentanil 3 μ g / kg; group B: low-dose nalbuphine group: 0.1 mg / kg of nabufen + 3 μ g / kg of sufentanil; group C: medium dose of nabufen group: 1 mg / kg of nabufen + 2 μ g / kg of sufentanil; group D: high-dose nabufen 2 There were 30 cases in each group. The degree of pain and the number of adverse reactions at 2, 4, 8, 12, 24 and 48 hours after operation were observed and recorded. The number and dosage of morphine used as a remedial analgesic were recorded. The pain degree was assessed by visual analogue scale (VAS). The total amount of analgesic pump used, the total number of times of pressing and the effective times of pressing were recorded. The adverse reactions included respiratory depression, nausea and vomiting, drowsiness, restlessness and skin The skin itches. Results: the analgesic effect of group B was similar to that of group A, and there was no significant difference in the number of invalid pressing, total pressing times and rescue analgesia rate (P > 0.05), while the invalid pressing times, total pressing times and remedial analgesia rate of group C and group D were significantly lower than those of group A (P < 0.05). There was no significant difference between group C and group D in the number of invalid compressions, the total number of compressions and the rate of remedial analgesia (P > 0.05), suggesting that increasing the dose of nalbuphine could not significantly increase the analgesic effect. The incidence of postoperative nausea and vomiting, skin pruritus, lethargy and Ramsay Sedation score in group B and group C were significantly lower than those in group A (P < 0.05). Ramsay Sedation score and incidence of drowsiness were lower than those in group D, which indicated that the incidence of adverse reactions was higher in group D than group B and group C.Conclusion: the combination of 1 mg / kg nabufen and 2 μ g / kg sufentanil is a safe and effective combination scheme for the prevention of visceral pain after gynecological laparoscopic surgery with small adverse reactions.Trial registration: http://www.chictr.org.cn/showproj.aspx?proj=40635Registration number：ChiCTR1900025076 . Prospectively registered on 10 August 2019.

Download Full-text

Fracture Resistance in Non-Vital Teeth: Absence of Interproximal Ferrule and Influence of Preparation Depth in CAD/CAM Endocrown Overlays—An In Vitro Study

Materials ◽

10.3390/ma15020436 ◽

2022 ◽

Vol 15 (2) ◽

pp. 436

Author(s):

Lucía Barallat ◽

María Arregui ◽

Sandra Fernandez-Villar ◽

Blanca Paniagua ◽

Andrés Pascual-La Rocca

Keyword(s):

Fracture Strength ◽

Fracture Resistance ◽

Testing Machine ◽

Compressive Force ◽

Ample Evidence ◽

Alveolar Crest ◽

Cad Cam ◽

Group A ◽

Group B ◽

Group D

There is ample evidence to support the use of endocrowns to restore endodontic teeth. However, the influence of the position of the interproximal margins on fracture strength has not yet been studied. The aim was to determine the relationship between the apicocoronal position of the interproximal restorative margins and fracture resistance in nonvital teeth restored with CAD/CAM endocrown overlays. Forty extracted human maxillary premolars were prepared for endocrown overlay restorations without ferrule on the interproximal aspects and classified according to the position of the interproximal restoration margins in relation to the alveolar crest: 2 mm (group A), 1 mm (group B), 0.5 mm (group C), and 0 mm (group D). Fracture strength was measured using a universal testing machine applying a compressive force to the longitudinal tooth axis. Group A had a mean fracture resistance of 859.61 (±267.951) N, group B 1053.9 (±333.985) N, group C 1124.6 (±291.172) N, and group D 780.67 (±183.269) N, with statistical differences between groups. Group C had the highest values for fracture strength compared to the other groups (p < 0.05). The location of the interproximal margins appears to influence the fracture resistance of CAD/CAM endocrown overlays. A distance of 0.5 mm between the interproximal margin and the alveolar crest was associated with increased fracture resistance.

Download Full-text

The Clinical Outcome in Patients with Peritoneal Metastasis

10.47363/jcbr/2020(2)113 ◽

2020 ◽

pp. 1-3

Author(s):

Spiliotis J ◽

◽

Farmakis D ◽

Raptis A ◽

Kopanakis N ◽

...

Keyword(s):

Systemic Chemotherapy ◽

Treatment Options ◽

Survival Rates ◽

Peritoneal Metastases ◽

Mortality And Morbidity ◽

Chemotherapy Group ◽

Significant Difference ◽

Group A ◽

Group B ◽

Group D

Cytroreductive surgery (CRS) and HIPEC are controversial effective treatment options for selected patients with peritoneal metastases. We retrospectively examined 4.500 patients with peritoneal metastases from different tumors from 2005 to 2020. Patients were divided in 4 groups, surgery plus HIPEC and then systemic chemotherapy: Group A n=730, Group B n=700, R0 surgery plus systemic chemotherapy, Group C n=870, palliative surgery plus systemic chemotherapy and Group D n=2.200, palliative care and best support. The postoperative outcomes, morbidity, mortality were compared between the 4 groups. The mean survival rates Group A=24,4+10,2m, Group B= 18,4+6,3m, Group C=12,3+5,7m, Group D=5,8+2,3m (p<0.05 between Gr A vr Gr B). There was no statistically significant difference in the 30-day mortality and morbidity. In conclusion CRS + HIPEC are feasible in 16% of our patients with peritoneal metastases and are associated with pro-longed survival.

Download Full-text