Influence of Different Diameters and Materials of Posts on the Fracture Resistance of Endodontically Treated Teeth

Objective: To evaluate the fracture resistance of endodontically treated teeth reinforced with cast titanium posts and prefabricated glass-fiber posts with different diameters. Materials and Methods: 50 recently extracted human maxillary central incisors were endodontically treated and randomly divided into 5 groups of 10 specimens each: Group A: 1.35mm diameter of cast titanium post; Group B: 1.5mm diameter of cast titanium post; Group C: 1.375mm diameter of prefabricated fiber post; Group D: 1.5mm diameter of prefabricated fiber post; Group E: resin restoration. All specimens were subjected to fracture resistance testing in a universal testing machine, statistical analysis was performed and the fracture modes were analyzed. Results: The mean fracture resistance of five groups as follows: 404.22±73.92N for group A, 488.17±78.68N for group B, 280.32±45.23N for group C, 317.53±50.87N for group D, 222.76±38.67N for group E. The fracture resistance of restored teeth between group C and group D had no significant difference (P>0.05). The fracture resistance of the rest pairwise group comparisons had significant difference (P<0.05). Most of cast post samples fractured at the root middle or apical portion, while most of the fiber post samples fractured at the root cervical or post fracture, which could be retreated. Conclusion: Human maxillary central incisors restored with cast posts could bear higher fracture load and fiber post could protect the root from fracture preferably.

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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.

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Fracture Resistance of Endodontically Treated Maxillary Premolars Restored by Various Direct Filling Materials: An In Vitro Study

International Journal of Biomaterials ◽

10.1155/2016/9138945 ◽

2016 ◽

Vol 2016 ◽

pp. 1-5 ◽

Cited By ~ 3

Author(s):

Jozef Mincik ◽

Daniel Urban ◽

Silvia Timkova ◽

Renata Urban

Keyword(s):

Fracture Resistance ◽

Endodontically Treated Teeth ◽

Mean Values ◽

Compression Load ◽

Significant Difference ◽

Group A ◽

Maxillary Premolars ◽

Group B ◽

Group D

The aim of this study is to compare the effect of various restorative materials on fracture resistance in maxillary premolars. Premolars (n=64) with no restorations or cracks were selected. MOD cavities were prepared considering the buccolingual width to be equal to half of the intercuspal distance. The specimens were randomly divided into 8 groups, 8 specimens each:group Aintact teeth,group Bunfilled cavity,group Ccomposite made by oblique layering technique,group Dcomposite with 2 mm cusp coverage,group Ebulk-filled posterior composite,group Fglass-ionomer,group Gamalgam, andgroup Hcomposite with proximal boxes. The specimens were subjected to an axial compression load with the mean values of fracture resistance in group A: 1289 N, group B: 181.75 N, group C: 445.38 N, group D: 645.88 N, group E: 355.13 N, group F: 352.00 N, group G: 191.38 N, and group H: 572.00 N. There was no significant difference between groups B and G, between C and D, E, and F, and between group D and H. All other measurements were statistically significant. We conclude that composite restoration with cusp coverage is the most ideal nonprosthetic solution for endodontically treated teeth. Cusp coverage increases the fracture resistance compared to the conventional cavity design.

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The Effect of Varying Ferrule Modes on Fracture Resistance of Canines Restored with One-Piece Milled Zirconia Post and Core

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.624.98 ◽

2012 ◽

Vol 624 ◽

pp. 98-102

Author(s):

Yao Kun Zhang ◽

Long Quan Shao ◽

Ruo Yu Liu ◽

Lin Lin Wang ◽

Jun Ai ◽

...

Keyword(s):

Fracture Resistance ◽

In Vitro Study ◽

Significant Difference ◽

Zirconia Crowns ◽

Group A ◽

Post And Core ◽

Resistance Decrease ◽

Group B ◽

Group D

The aim of this invitro study was to evaluate the fracture resistance of endodontically treated canines restored with one-piece milled zirconia post and core in the varying ferrule modes. Fifty recently extracted human maxillary canines were endodontically treated and randomly divided into 5 groups of 10 specimens each. According to the defect degree of ferrule, intact ferrule was classified as group A and served as control, 2 mm ferrule height without buccal ferrule was classified as group B, 2 mm ferrule height without mesial and buccal ferrule was classified as group C, 2 mm ferrule height without mesial, buccal and lingual ferrule was classified as group D, no ferrule preparation was classified as group E. All of the teeth were restored with one-piece milled zirconia post and core, and zirconia crowns. The teeth were prepared to standardized specifications. The restored teeth were loaded to fracture at a 135° angle to their long axis, at a cross-head speed 0.5 mm/min, and the load (N) at failure was recorded. Statistical analysis was performed by SNK pairwise multiple comparisons (α=0.05). The mean fracture resistance of five groups as follows: 1019.30±139.01N for group A, 861.20±105.67N for group B, 833.70±100.56N for group C, 733.20±96.91N for group D, 698.00±99.90N for group E. The fracture resistance of restored teeth between group B and group C, group D and group E had no statistically significant difference(P>0.05). The fracture resistance of the rest pairwise group comparisons had statistically significant difference(P<0.05). Increasing the absence degree of ferrule, it was found that the fracture resistance decrease. The buccal and lingual ferrule were more important than mesial ferrule for enhanced fracture resistance. This in vitro study supports evidence that reserving the buccal and lingual ferrule is a key point to increase the fracture resistance of canines restored with one-piece milled zirconia post and core.

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Base Materials’ Influence on Fracture Resistance of Molars with MOD Cavities

Materials ◽

10.3390/ma14185242 ◽

2021 ◽

Vol 14 (18) ◽

pp. 5242

Author(s):

Gabriela Ciavoi ◽

Ruxandra Mărgărit ◽

Liana Todor ◽

Dana Bodnar ◽

Magdalena Natalia Dina ◽

...

Keyword(s):

Fracture Resistance ◽

Glass Ionomer Cement ◽

Base Material ◽

Glass Ionomer ◽

Base Materials ◽

Significant Difference ◽

Group A ◽

Group B ◽

Group D ◽

Ionomer Cement

The aim of this study was to compare fracture resistance of teeth presenting medium-sized mesial-occlusal-distal (MOD) cavities using different base materials. Thirty-six extracted molars were immersed for 48 h in saline solution (0.1% thymol at 4 °C) and divided into six groups. In group A, the molars were untouched, and in group B, cavities were prepared, but not filled. In group C, we used zinc polycarboxylate cement, in group D—conventional glass ionomer cement, in group E—resin modified glass ionomer cement, and in group F—flow composite. Fracture resistance was tested using a universal loading machine (Lloyd Instruments) with a maximum force of 5 kN and a crosshead speed of 1.0 mm/min; we used NEXYGEN Data Analysis Software and ANOVA Method (p < 0.05). The smallest load that determined the sample failure was 2780 N for Group A, 865 N for Group B, 1210 N for Group C, 1340 N for Group D, 1630 N for Group E and 1742 N for Group F. The highest loads were 3050 N (A), 1040 N (B), 1430 N (C), 1500 N (D), 1790 N (E), and 3320 N (F), the mean values being 2902 ± 114 N (A), 972 ± 65 N (B), 1339 ± 84 N (C), 1415 ± 67 N (D), 1712 ± 62 N (E), and 2334 ± 662 N (F). A p = 0.000195 shows a statistically significant difference between groups C, D, E and F. For medium sized mesial-occlusal-distal (MOD) cavities, the best base material regarding fracture resistance was flow composite, followed by glass ionomer modified with resin, conventional glass ionomer cement and zinc polycarboxylate cement. It can be concluded that light-cured base materials are a better option for the analyzed use case, one of the possible reasons being their compatibility with the final restoration material, also light-cured.

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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.

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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.

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Comparative Evaluation of Fracture Resistance of Endodontically Treated Teeth Restored with Resin Fiber Post and Stainless Steel Post: An In Vitro Study

Dental Journal of Advance Studies ◽

10.1055/s-0038-1672019 ◽

2015 ◽

Vol 03 (02) ◽

pp. 080-084

Author(s):

Vijay Singh ◽

Poonam Bogra ◽

Saurabh Gupta ◽

Navneet Kukreja ◽

Neha Gupta

Keyword(s):

Stainless Steel ◽

Fracture Resistance ◽

Testing Machine ◽

Compressive Force ◽

Control Group ◽

Fiber Post ◽

Endodontically Treated Teeth ◽

Group I ◽

Significant Difference

AbstractFracture resistance of endodontically treated teeth restored with post. Aims: This study aims to compare the fracture resistance of endodontically treated teeth restored with resin fiber and stainless steel post. Commercially available prefabricated resin fiber post(Dentsply Maillefer Easy Post), prefabricated stainless steel post(Coltene/Whaledent Parapost) were used. Methods and Material: Forty five maxillary central incisors were obturated and divided into 3 groups: Control Group (Group I) without any post (n = 15), Resin Fiber Post Group (Group II) (n = 15) and Stainless Steel Post Group (Group III) (n = 15). In all Groups except control group, post space was prepared; a post was cemented, and a core build-up was provided. All the specimens were subjected to compressive force under a universal testing machine until fracture. Statistical analysis used: The results were analyzed using the variable analysis test (ANOVA). Results: One-way analysis of variance revealed significant difference among test groups. The control group demonstrated highest fracture resistance (925.2183 N), followed by the resin fiber post group (486.7265 N) and stainless steel post group (423.539N). Conclusions: Teeth restored with resin fiber post showed higher fracture resistance values than prefabricated stainless steel post.

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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.

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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.

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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.

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