Effect of Composite Insertion Technique on Cuspal Deflection Using an In Vitro Simulation Model

2012 ◽  
Vol 37 (3) ◽  
pp. 299-305 ◽  
Author(s):  
S Jafarpour ◽  
W El-Badrawy ◽  
HS Jazi ◽  
D McComb
Keyword(s):  
Insertion Technique ◽  
Adhesive Resin ◽  
Group A ◽  
In Vitro Simulation ◽  
Maxillary Premolars ◽  
Insertion Techniques ◽  
Group B ◽  
Artificial Teeth ◽  
Bulk Insertion

SUMMARY Objective The objective of this study was to investigate, by simulation, the effect of conventional composite resin insertion techniques on cuspal deflection using bonded typodont artificial teeth. The deflection produced by a new low-shrinkage composite was also determined. Materials and Methods Sixty standardized MOD preparations on ivorine maxillary premolars were prepared: group A at 4 mm depth and group B at 6 mm depth. Each group was further subdivided according to composite insertion technique (n=6), as follows: 1) bulk insertion, 2) horizontal increments, 3) tangential increments, and 4) a modified tangential technique. Preparations were microetched, acid-cleaned, and bonded with adhesive resin to provide micromechanical attachment before restoration with a conventional composite (Spectrum TPH3, Dentsply). Two additional subgroups at 4 mm and 6 mm depth (n=6) were restored in bulk using low-shrinkage composite (Filtek LS, 3M/ESPE). All groups received the same total photo-polymerization time. Cuspal deflection was measured during the restorative procedure using two Linear Variable Differential Transformers attached to a data acquisition system. Results The average cuspal deflections for group A were 1) 40.17 ± 1.18 μm, 2) 25.80 ± 4.98 μm, 3) 28.27 ± 5.12 μm, and 4) 27.33 ± 2.42 μm. The deflections in group B were 1) 38.82 ± 3.64 μm, 2) 50.39 ± 9.17 μm, 3) 55.62 ± 8.16 μm, and 4) 49.61 ± 8.01 μm. Cuspal flexure for the low-shrinkage composite was 11.14 ± 1.67 μm (group A: 4 mm depth) and 16.53 ± 2.79 μm (group B: 6 mm depth). Conclusions All insertion techniques using conventional composite caused cuspal deformation. In general, deeper preparations showed increased cuspal deflection—except in the case of bulk insertion, which was likely affected by decreased depth of cure. Cuspal movement using low-shrinkage composite was significantly reduced.

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

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
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.

Factor II Related Antigen and Antithrombin III Levels as Indicators of Liver Failure in Consumption Coagulopathy

1982 ◽  
Vol 47 (03) ◽  
pp. 218-220 ◽  
Author(s):  
P Sié ◽  
E Letrenne ◽  
C Caranobe ◽  
M Genestal ◽  
B Cathala ◽  
...  
Keyword(s):  
Liver Failure ◽  
Antithrombin Iii ◽  
Coagulation Factors ◽  
Consumption Coagulopathy ◽  
Blood Coagulation Factors ◽  
Factor Ii ◽  
At Iii ◽  
Group A ◽  
Group B

SummaryIn order to detect impaired synthesis of blood coagulation factors associated to consumption coagulopathy, a simultaneous evaluation of factor II-related antigen (II rAg) and of antithrombin III (AT III) was carried out in 16 patients affected with severe defibrination. An in vitro preliminary study on plasma and serum demonstrated that the levels of II rAg and of AT III, assessed by the Laurell technique with Behring antisera, were not reduced by the coagulation process. The patients were, a posteriori, classified into two groups according to the absence (group A) or the presence (group B) of factors predisposing to liver failure such as metastasis, cirrhosis, and prolonged shock. II rAg and AT III levels are significantly correlated; they are in the normal range in group A but reduced in group B. Thus II rAg or AT III level determinations are useful markers in the detection of liver failure associated to the consumption phenomenon. These results also suggest that part of the decreased AT III levels reported in severe cases of disseminated intravascular coagulation may be the consequence of an associated liver failure.

scholarly journals The Impact of Left Atrial Size in Catheter Ablation of Atrial Fibrillation Using Remote Magnetic Navigation

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Xiao-yu Liu ◽  
Hai-feng Shi ◽  
Jie Zheng ◽  
Ku-lin Li ◽  
Xiao-xi Zhao ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Catheter Ablation ◽  
Left Atrial ◽  
Magnetic Navigation ◽  
Remote Magnetic Navigation ◽  
X Ray ◽  
Group A ◽  
Group B ◽  
The Impact

Objective. The objective of this study was to investigate the impact of left atrial (LA) size for the ablation of atrial fibrillation (AF) using remote magnetic navigation (RMN). Methods. A total of 165 patients with AF who underwent catheter ablation using RMN were included. The patients were divided into two groups based on LA diameter. Eighty-three patients had small LA (diameter <40 mm; Group A), and 82 patients had a large LA (diameter ≥40 mm; Group B). Results. During mapping and ablation, X-ray time (37.0 (99.0) s vs. 12 (30.1) s, P<0.001) and X-ray dose (1.4 (2.7) gy·cm2 vs. 0.7 (2.1) gy·cm2, P=0.013) were significantly higher in Group A. No serious complications occurred in any of the patients. There was no statistical difference in the rate of first anatomical attempt of pulmonary vein isolation between the two groups (71.1% vs. 57.3%, P=0.065). However, compared with Group B, the rate of sinus rhythm was higher (77.1% vs. 58.5%, P<0.001) during the follow-up period. More patients in Group A required a sheath adjustment (47/83 vs. 21/82, P<0.001), presumably due to less magnets positioned outside of the sheath. In vitro experiments with the RMN catheter demonstrated that only one magnet exposed created the sheath affects which influenced the flexibility of the catheter. Conclusions. AF ablation using RMN is safe and effective in both small and large LA patients. Patients with small LA may pose a greater difficulty when using RMN which may be attributed to the fewer magnets beyond the sheath. As a result, the exposure of radiation was increased. This study found that having at least two magnets of the catheter positioned outside of the sheath can ensure an appropriate flexibility of the catheter.

Salivary oestradiol and progesterone after in vitro fertilization and embryo transfer using different luteal support regimens

1990 ◽  
Vol 2 (4) ◽  
pp. 351 ◽  
Author(s):  
YF Wong ◽  
EP Loong ◽  
KR Mao ◽  
PP Tam ◽  
NS Panesar ◽  
...  
Keyword(s):  
In Vitro Fertilization ◽  
Embryo Transfer ◽  
Luteal Phase ◽  
Biologically Active ◽  
Luteal Support ◽  
Vitro Fertilization ◽  
Group A ◽  
Group B ◽  
Ivf Et

Salivary oestradiol (E2) and progesterone (P) levels have been shown to reflect the biologically active fractions in the serum. The luteal-phase status of stimulated cycles was investigated after in vitro fertilization and embryo transfer (IVF-ET). Thirty patients were randomly allocated to one of three luteal therapy groups: group A had no support, group B had intramuscular P and group C had intramuscular P and human chorionic gonadotrophin (hCG). One pregnancy was achieved in group A, two in group B and three in group C. Significant correlations between salivary and serum levels of E2 and of P in matched samples during luteal phase were found. Salivary E2 levels from luteal day 8 through day 14 and P levels from day 3 through day 14 were significantly higher in the pregnant than in the nonpregnant cycles. Among the nonpregnant cycles, salivary E2 and P levels were significantly higher in group C than in group A or B. These findings suggest that, in stimulated cycles for IVF-ET, determination of salivary E2 and P levels may be used as reliable alternatives to serum concentrations for assessing the luteal phase. Also, the additional hCG has an enhanced luteotrophic effect, as reflected by the higher salivary E2 and P levels, which may lead to a better pregnancy rate.

Effects of Mechanical Stimulation on MMP-2 and TIMP-2 Expression of Scleral Fibroblasts after Posterior Sclera Reinforcement

2014 ◽  
Vol 490-491 ◽  
pp. 867-871
Author(s):  
Guo Hui Wang ◽  
Wei Yi Chen
Keyword(s):  
Mechanical Stimulation ◽  
Sine Wave ◽  
Posterior Pole ◽  
Cyclic Stretch ◽  
Elisa Method ◽  
Band Group ◽  
Group A ◽  
Operation Group ◽  
Group B

To understand the effect of mechanical stimulation on posterior sclera reinforcement (PSR), the rabbit scleral fibroblasts after PSR were subjected to stretch in vitro and MMP-2 and TIMP-2 expression of scleral fibroblasts were evaluated. Three-week-old rabbits were monocularly performed by eyelid suturation randomly to prepare experimental myopia eye. After 60 days, the experimental myopia eyes were treated by PSR. After 6 months, the posterior pole scleral fibroblasts (normal sclera - group A, sclera after operation - group B and fusion region of sclera and reinforcing band group C) were isolated and cultured in vitro. The cells were subjected to cyclic stretch regimens (sine wave, 3% and 6% elongation amplitude, 0.1Hz, 48h duration) by FX-4000 Tension System. The MMP-2 and TIMP-2 expression of scleral fibroblasts were evaluated by ELISA method. The results show that after cyclic stretch to the scleral fibroblasts of the normal sclera and the sclera after operation, the MMP-2 expression was significantly reduced and the TIMP-2 expression was significantly increased, the MMP-2 and TIMP-2 expression of the scleral fibroblasts of the fusion region after operation was no changed. It was indicated that the mechanical stimulation could regulate the MMP-2 and TIMP-2 expression of scleral fibroblasts and play an important role in the process of treating high myopia with PSR surgery.

scholarly journals Photopolymerizable Injectable Cartilage Mimetic Hydrogel for the Treatment of Focal Chondral Lesions: A Proof of Concept Study in a Rabbit Animal Model

2018 ◽  
Vol 47 (1) ◽  
pp. 212-221 ◽  
Author(s):  
Cecilia Pascual-Garrido ◽  
Elizabeth A. Aisenbrey ◽  
Francisco Rodriguez-Fontan ◽  
Karin A. Payne ◽  
Stephanie J. Bryant ◽  
...  
Keyword(s):  
Animal Model ◽  
Chondrogenic Differentiation ◽  
Osteochondral Lesions ◽  
Chondral Defect ◽  
Group A ◽  
Group B ◽  
Safranin O

Background: In this study, we investigate the in vitro and in vivo chondrogenic capacity of a novel photopolymerizable cartilage mimetic hydrogel, enhanced with extracellular matrix analogs, for cartilage regeneration. Purpose: To (1) determine whether mesenchymal stem cells (MSCs) embedded in a novel cartilage mimetic hydrogel support in vitro chondrogenesis, (2) demonstrate that the proposed hydrogel can be delivered in situ in a critical chondral defect in a rabbit model, and (3) determine whether the hydrogel with or without MSCs supports in vivo chondrogenesis in a critical chondral defect. Study Design: Controlled laboratory study. Methods: Rabbit bone marrow–derived MSCs were isolated, expanded, encapsulated in the hydrogel, and cultured in chondrogenic differentiation medium for 9 weeks. Compressive modulus was evaluated at day 1 and at weeks 3, 6, and 9. Chondrogenic differentiation was investigated via quantitative polymerase reaction, safranin-O staining, and immunofluorescence. In vivo, a 3 mm–wide × 2-mm-deep chondral defect was created bilaterally on the knee trochlea of 10 rabbits. Each animal had 1 defect randomly assigned to be treated with hydrogel with or without MSCs, and the contralateral knee was left untreated. Hence, each rabbit served as its own matched control. Three groups were established: group A, hydrogel (n = 5); group B, hydrogel with MSCs (n = 5); and group C, control (n = 10). Repair tissue was evaluated at 6 months after intervention. Results: In vitro, chondrogenesis and the degradable behavior of the hydrogel by MSCs were confirmed. In vivo, the hydrogel could be delivered intraoperatively in a sterile manner. Overall, the hydrogel group had the highest scores on the modified O’Driscoll scoring system (group A, 17.4 ± 4.7; group B, 13 ± 3; group C, 16.7 ± 2.9) ( P = .11) and showed higher safranin-O staining (group A, 49.4% ± 20%; group B, 25.8% ± 16.4%; group C, 36.9% ± 25.2%) ( P = .27), although significance was not detected for either parameter. Conclusion: This study provides the first evidence of the ability to photopolymerize this novel hydrogel in situ and assess its ability to provide chondrogenic cues for cartilage repair in a small animal model. In vitro chondrogenesis was evident when MSCs were encapsulated in the hydrogel. Clinical Relevance: Cartilage mimetic hydrogel may offer a tissue engineering approach for the treatment of osteochondral lesions.

scholarly journals In vitro Comparison of Apically Extruded Debris during Root Canal Retreatment with Rotary and Reciprocating Systems

2019 ◽  
Vol 13 (1) ◽  
pp. 488-492
Author(s):  
María J. Burbano Balseca ◽  
Silvana B. Terán Ayala ◽  
Fábio D. da Costa Aznar ◽  
Adriana R. de Freitas-Aznar ◽  
Guillermo M. Aguirre Balseca ◽  
...  
Keyword(s):  
Similar Amount ◽  
Hybrid Technique ◽  
Significance Level ◽  
Sealing Material ◽  
Apical Extrusion ◽  
Root Canal Retreatment ◽  
Group A ◽  
Group B ◽  
Reciprocating Systems

Introduction: The extrusion of apical detritus during the retracting procedure is very important, as, besides eliminating materials of radicular obturation, aggressive agents and products such as the remains of dentin taken out, and microorganisms are generally located in tissue around the roots, producing undesired effects, such as inflammation, acute pain, post-operatory pain and delays in the periapical treatment. Objective: To determine the amount of apically extruded detritus using rotary and reciprocating retreatment systems. Methodology: An experimental comparative study as conducted in which 40 single-rooted human first premolars were analyzed. The instruments used were ProTaper Universal files up to F3 and sodium hypochlorite, and the sealing was made through the hybrid technique Tager. They were then kept at 37ºC and 100% of humidity for 15 days so that the sealing material would seal. For the retracting procedure, experimental tubes previously weighted were used. The sample was divided randomly into two groups of 20 pieces. Group A: ProTaper R, and group B: Reciproc. Then, the irrigating material (distilled water) was evaporated from the tubes for 12 hours in a stove at 105ºC, and the experimental tubes were weighted in an analytical precision weighing scale 10-5g. The data was analyzed through the T Student with a significance level of 5%. Results: Results indicated that groups A and B, retreatment with rotational ProTaper R and reciprocating retreatment system (Reciproc) showed a similar difference of initial and final weights, indicating similar apical extrusion of detritus. Conclusion: Both systems extruded a similar amount of detritus during the retreatment procedures.

scholarly journals Frictional Characteristics of the Newer Low-friction Elastomeric Ligatures

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.

scholarly journals Laser versus LED polymerization: Comparison of in vitro preventive sealing procedures

2019 ◽  
Vol 17 (1) ◽  
pp. 228080001881601
Author(s):  
Filiberto Mastrangelo ◽  
Isabella Perraro ◽  
Sabrina Mattia ◽  
Giuseppe Troiano ◽  
Khrystyna Zhurakivska ◽  
...  
Keyword(s):  
Laser Diode ◽  
Tooth Enamel ◽  
In Vitro Study ◽  
Third Molars ◽  
Fissure Sealant ◽  
Microscopic Evaluation ◽  
Group A ◽  
Group B ◽  
Metallization Process

Introduction: The technique of sealing is a widely accepted procedure for prevention of caries. The aim of our in vitro study was to compare the effect of two different curing units (traditional LED source and innovative laser diode lamp) on the integrity of fissure sealant material and its interface with tooth enamel. Materials and methods: Sixty healthy third molars were randomly assigned to two groups. In group A were teeth intended for polymerization by LED B lamp, and group B comprised teeth to be polymerized by an innovative laser diode. Both groups were treated with the traditional sealing technique, subjected to a metallization process, and analyzed by scanning electron microscope. Results: Micro-gaps between the sealant and the enamel were found in specimens in both A (43%) and B (40%) groups ( p=0.793), and sealant shrinkage was seen. Significant differences between the groups emerged in the percentage of perimetric micro-erosion sites (80% vs. 100%, p=0.010) and the presence of holes and micro-bubbles on the sealant surface (21% vs. 63%, p=0.001). Conclusions: Although macroscopic clinical polymerization occurred with both instruments, the microscopic evaluation showed significant differences between the studied groups in terms of perimetric micro-erosion sites and micro-bubbles, which were higher in laser-cured samples.

scholarly journals Deformation of the Internal Connection of Narrow Implants after Insertion in Dense Bone: An in Vitro Study

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1833 ◽  
Author(s):  
Rafael Delgado-Ruiz ◽  
Ana Nicolas Silvente ◽  
Georgios Romanos
Keyword(s):  
In Vitro Study ◽  
Surface Damage ◽  
Insertion Torque ◽  
Type Ii ◽  
Before And After ◽  
Post Test ◽  
Group A ◽  
Group B ◽  
Connection Length

Implant connections must resist surgical and prosthetic procedures without deformation. This study evaluated the deformation of different internal connections (IC) of narrow dental implants (NDI) after their insertion in artificial dense bone. Thirty NDI, with different IC geometries, Group A (internal hexagon), Group B (tri-channeled), and Group C (four-channeled), with the same length and similar narrow diameters, were inserted in type II density bone blocks. Drilling protocols for dense bone from each implant manufacturer were followed. The Insertion torque (IT), connection length, vertex angles, and wall deformations were analyzed before and after the insertion of the implants. ANOVA (Analysis of Variance) and Tukey post-test were used for statistical comparisons. IT values were higher for Group A, surface damage, and titanium particles were observed in the IC in all the groups. Angle deformations between 5 and 70 degrees were present in all the groups, and the walls of Group B connection were the most affected by deformations (p < 0.05). Within the limitations of this experiment, it can be concluded that narrow diameter implants will suffer deformation of the implant connection and will also experience surface damage and titanium particle release when inserted in type II bone density.

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