scholarly journals Fracture resistance and 3D finite element analysis of machined ceramic crowns bonded to endodontically treated molars with two planes versus flat occlusal preparation designs: an in vitro study

F1000Research ◽  
2021 ◽  
Vol 8 ◽  
pp. 1020
Author(s):  
Omnia Nabil ◽  
Carl Hany Halim ◽  
Ashraf Hassan Mokhtar
Keyword(s):  
Stress Distribution ◽  
Fracture Resistance ◽  
Element Analysis ◽  
3D Finite Element ◽  
Mean Values ◽  
Group I ◽  
Group Ii ◽  
The Impact ◽  
Preparation Design ◽  
Distribution Of Stresses

Background: The flat occlusal preparation design (FOD) of posterior teeth offers promising results of fracture resistance and stress distribution, but its application in vital teeth is limited as there may be a danger of pulp injury. Although this danger is omitted in endodontically treated teeth, there is no research work assessing the impact of FOD on the fracture resistance and distribution of stresses among these teeth. The aim of this study was to assess the impact of FOD of endodontically treated molars on the fracture resistance and distribution of stresses among a ceramic crown-molar structure when compared to the two planes occlusal preparation design (TOD). Methods: 20 human mandibular molars were endodontically treated and distributed equally to two groups: Group I (TOD) and Group II (FOD). Ceramic CAD/CAM milled lithium disilicate (IPS e.max CAD) crowns were produced for all preparations and adhered using self-adhesive resin cement. Using a universal testing machine, the fracture resistance test was performed. The fractured samples were examined using a stereomicroscope and scanning electron microscope to determine modes of failure. Stress distribution was evaluated by 3D finite element analysis, which was performed on digital models of endodontically treated mandibular molars (one model for each design). Results: Group II recorded statistically non-significant higher fracture resistance mean values (3107.2± 604.9 N) than Group I mean values (2962.6 ±524.27 N) as indicated by Student’s t-test (t=0.55, p= 0.57). Also, Group II resulted in more favorable failure mode as compared to Group I. Both preparation designs yielded low von-Mises stresses within the factor of safety. However, the stress distribution among different layers of the model differed. Conclusions: FOD having comparable fracture strength to TOD and a more favorable fracture behavior can be used for the preparation of endodontically treated molars.

scholarly journals Fracture resistance and 3D finite element analysis of machined ceramic crowns bonded to endodontically treated molars with two planes versus flat occlusal preparation designs: an in vitro study

F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 1020 ◽  
Author(s):  
Omnia Nabil ◽  
Carl Hany Halim ◽  
Ashraf Hassan Mokhtar
Keyword(s):  
Stress Distribution ◽  
Fracture Resistance ◽  
Element Analysis ◽  
3D Finite Element ◽  
Mean Values ◽  
Group I ◽  
Group Ii ◽  
The Impact ◽  
Preparation Design ◽  
Distribution Of Stresses

Background:The flat occlusal preparation design (FOD) of posterior teeth offers promising results of fracture resistance and stress distribution, but its application in vital teeth is limited as there may be a danger of pulp injury. Although this danger is omitted in endodontically treated teeth, there is no research work assessing the impact of FOD on the fracture resistance and distribution of stresses among these teeth. The aim of this study was to assess the impact of FOD of endodontically treated molars on the fracture resistance and distribution of stresses among a ceramic crown-molar structure when compared to the two planes occlusal preparation design (TOD).Methods:20 human mandibular molars were endodontically treated and distributed equally to two groups: Group I (TOD) and Group II (FOD). Ceramic CAD/CAM milled lithium disilicate (IPS e.max CAD) crowns were produced for all preparations and adhered using self-adhesive resin cement. Using a universal testing machine, the fracture resistance test was performed. The fractured samples were examined using a stereomicroscope and scanning electron microscope to determine modes of failure. Stress distribution was evaluated by 3D finite element analysis, which was performed on digital models of endodontically treated mandibular molars (one model for each design).Results:Group II recorded statistically non-significant higher fracture resistance mean values (3107.2± 604.9 N) than Group I mean values (2962.6 ±524.27 N) as indicated by Student’s t-test (t=0.55, p= 0.57). Also, Group II resulted in more favorable failure mode as compared to Group I. Both preparation designs yielded low von-Mises stresses within the factor of safety. However, the stress distribution among different layers of the model differed.Conclusions:FOD having comparable fracture strength to TOD and a more favorable fracture behavior can be used for the preparation of endodontically treated molars.

scholarly journals Fatigue resistance and 3D finite element analysis of machine-milled ceramic occlusal veneers with new preparation designs versus conventional design: an in vitro study

F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 1038 ◽  
Author(s):  
Samaa Kotb ◽  
Atef Shaker ◽  
Carl Halim
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Resistance ◽  
Element Analysis ◽  
3D Finite Element ◽  
Group Iii ◽  
Conventional Design ◽  
Group I ◽  
Group Ii ◽  
Preparation Design

Background: Treatment of patients with severe tooth wear is complex. Treatments involving more tooth structure removal may be inappropriate for patients who have already lost a significant amount of dental tissue due to erosion. The aim of this study was to evaluate the effect of two modified occlusal veneer preparations on the fatigue resistance and stress distribution of bonded occlusal veneers, in comparison to the conventional preparation design. Methods: A total of 54 human mandibular molars were distributed into three equal groups of n=18 teeth each, according to the occlusal veneer preparation design, where group I (conventional design) received Planar occlusal veneer preparation, group II (occlusal veneer with circumferential finish line) and group III (occlusal veneer with intracoronal cavity extension). For the manufacture of all the veneers using machinable zirconium lithium silicate glass ceramic blocks, a computer aided design/manufacturing system was used. A dual cure, adhesive resin cement was used to bond all occlusal veneers to corresponding prepared teeth. After storage in water for one week, step-stress (accelerated life testing was performed for all samples. Finite element analysis was carried out as well to evaluate the distribution of stresses. Results: The highest values (mean±SD) were recorded for group II (890.57±211.53 N) followed by Group I values (883.54±135.91 N), while the lowest values were recorded for Group III (875.57±143.52 N). The difference between groups was statistically non-significant as indicated by ANOVA (P=0.9814>0.05). The stress values were generally found to be low and their distribution differed among groups. Conclusion: Group I and II showed comparable fatigue resistance and more favourable failure behaviour when compared to Group III based on the fractographic and 3D finite element analyses.

scholarly journals Impact of hemodialysis on the wellbeing of chronic kidney diseases patients: a pre-post analysis

2020 ◽  
Vol 27 (1) ◽  
Author(s):  
Um-e-Kalsoom ◽  
Sabiha Khan ◽  
Israr Ahmad
Keyword(s):  
Quality Of Life ◽  
Social Support ◽  
Perceived Social Support ◽  
Kidney Diseases ◽  
Chronic Kidney Diseases ◽  
Group I ◽  
Significant Difference ◽  
Group Ii ◽  
The Impact

Abstract Background Hemodialysis may have serious psychological impact upon patients suffering from chronic kidney diseases. The aim of the present study is to investigate the impact of hemodialysis on the wellbeing of individuals with chronic kidney diseases (CKD). Result A sample consists of (N = 100) CKD patients referred from neurology ward of Leady Reading Hospital Peshawar. Data was collected from both male (50%) and female (50%) in 2017. Participants were divided into two groups on the basis of pre-set criteria. In group I, individuals with 4–5 stage of CKD referred first time for dialysis treatment were recruited. Group II comprised of CKD patients with 1–3 stage. Demographic data sheet, Pakistan Anxiety and Depression, WHO Quality of Life scale, and Perceived Social support scale (PSS) were used to test the hypotheses. Paired sample t test was use to see the difference between pre- and post-analysis of depression, anxiety, QOL, and PSS in group I (experimental group). Results suggests significant difference on depression (p > .001), anxiety (p > .001), and QOL (p > .001), while no significant difference was reported on perceived social support (p <.673). Findings also indicate no significant difference between group I and group II on QOL depression, anxiety, and PSS. Conclusion The findings concluded that patients under hemodialysis treatment suffered from depression, anxiety, and poor quality of life.

scholarly journals The impact of ureteral Double-J stent insertion following ureterorenoscopy in patients with ureteral stones accompanied by perirenal fat stranding

2018 ◽  
Vol 90 (1) ◽  
pp. 15
Author(s):  
Ercan Ogreden ◽  
Ural Oguz ◽  
Erhan Demirelli ◽  
Erdal Benli ◽  
Özkan Özen
Keyword(s):  
Ureteral Stone ◽  
Ureteral Stones ◽  
Stent Insertion ◽  
Female Ratio ◽  
Group I ◽  
Dj Stent ◽  
Group Ii ◽  
Fat Stranding ◽  
The Impact ◽  
Perirenal Fat

Objective: To evaluate the impact of ureteral stent insertion following semirigid ureterorenoscopy (URS) in patients with perirenal fat stranding (PFS) due to ureteral stones. Material and methods: Data of 600 patients who underwent URS were analyzed retrospectively. Seventy-two patients detected to have PFS accompanying ureteral stone were included. Patients who did not undergo double J (DJ) stent insertion following semirigid URS were classified as Group I (n: 52), while those who underwent stent insertion were classified as Group II (n: 20). Side distribution; localization of the stones, stone size, presence of fever, urinary tract infection (UTIs) and urosepsis rates were compared in the two groups. Results: The average age of the patients was 44.4 (20-71) years. Male/female ratio and side of the stone location showed similar distribution in both groups (p > 0.05). Fever occurred in 23 cases (44.2%) in Group I and in 15 cases (75%) in Group II (p = 0.038). UTIs occurred in 15 cases (28.9%) in Group I and in 12 cases (60%) in Group II (p = 0.03). Urosepsis presented in 3 (5.8%) and 5 (25%) of the patients in Group I and II, respectively (p = 0.033). Conclusions: According to our results, ureteral DJ stent insertion following URS in patients with PFS due to ureteral stone caused an increase on postoperative infection related complications.

Psychosocial profile of encopretic children and their caregivers in relation to parenting style

2016 ◽  
Vol 33 (S1) ◽  
pp. S362-S362 ◽  
Author(s):  
E. Zaky ◽  
M. Rashad ◽  
H. Elsafoury ◽  
E. Ismail
Keyword(s):  
Parenting Style ◽  
Parenting Styles ◽  
Healthy Controls ◽  
Psychosocial Profile ◽  
Group I ◽  
Egyptian Children ◽  
Paternal Anxiety ◽  
Group Ii ◽  
Anxiety Depression ◽  
The Impact

BackgroundThe role of psychological factors in the development and maintenance of encopresis is controversial.ObjectivesAssessment of the psychosocial profile of encopretic children and their caregivers in relation to parenting style compared to controls.MethodologyThe current cross sectional study comprised 90 Egyptian children classified into three groups: group I (encopresis without constipation and overflow incontinence), group II (encopresis with constipation and overflow incontinence), and group III (clinically healthy controls); each group included 30 children. Thorough clinical evaluation and psychometric assessment were carried out for all enrolled children while caregivers were evaluated for their parenting styles, anxiety, depression, and introversion scores.ResultsHardness, undue blaming, and indecisive parenting styles were significantly more prevalent among caregivers of group I. Encopretic children of group I & II had poorer self-esteem and higher prevalence of clinically manifest depression compared to healthy controls. Furthermore, there was a higher prevalence of clinically manifest paternal anxiety, depression, and introversion and maternal depression among caregivers of group II and higher prevalence of clinically manifest paternal anxiety and depression among fathers of group I.ConclusionThe approach of toilet training, not the time of its initiation, seems to be the factor that really matters in predisposing to and perpetuating encopresis. Further exploration is needed to determine if the documented association of psychological disorders of enrolled encopretic children and their caregivers was causal or being just the impact of the child's encopresis.Disclosure of interestThe authors have not supplied their declaration of competing interest.

scholarly journals Fracture Strength and Stress Distribution in Premolars Restored with Cast Post-and-Cores or Glass-Fiber Posts Considering the Influence of Ferule

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Atais Bacchi ◽  
Ricardo Armini Caldas ◽  
Daniel Schmidt ◽  
Mauricio Detoni ◽  
Matheus Albino Souza ◽  
...  
Keyword(s):  
Stress Distribution ◽  
Glass Fiber ◽  
Fracture Strength ◽  
Lower Percentage ◽  
Element Analysis ◽  
Mean Values ◽  
Failure Patterns ◽  
Fiber Posts ◽  
Glass Fiber Posts ◽  
Post And Core

Objectives. The aim of this study was to evaluate the influence of ferule and the post type on the fracture strength and stress distribution in premolars. Materials and Methods. Forty human mandibular premolars were decoronated, allocated in four groups, and restored as follows: CPC-NF: cast post-and-core and absence of ferule; CPC-F: cast post-and-core and presence of ferule; FPC-NF: glass-fiber posts and absence of ferule; FPC-F: glass-fiber posts and presence of ferule. The fracture strength (FS) and failure patterns were evaluated. Finite element analysis (FEA) evaluated the stress distribution. Results. FS did not differ between CPCs and FPC either in presence or in absence of ferule. The presence of ferule increased FS with both post types. Mean values of FS for ferule groups were higher than functional or parafunctional loads reported in literature, which was not the case for FPC-NF when compared to parafunctional loads. FEA with a functional load showed slightly higher compressive stresses in dentin in the group CPC-NF, which was much lower than the compressive strength of dentin. Lower percentage of catastrophic failures was observed in nonferule groups irrespective of post type, which was explained by the stress concentration in the cervical root region when FEA with the FS load was simulated. Conclusion. Ferule effect was shown to be more important than post type in the analysis. Both posts showed potential to withstand functional loads irrespective of presence of ferule. However, the mean FS was lower than parafunctional loads for FPC in the absence of ferule.

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