scholarly journals Healing Pattern Analysis for Dental Implants Using the Mechano-Regulatory Tissue Differentiation Model

2020 ◽  
Vol 21 (23) ◽  
pp. 9205
Author(s):  
Ming-Jun Li ◽  
Pei-Ching Kung ◽  
Yuan-Wei Chang ◽  
Nien-Ti Tsou
Keyword(s):  
Dental Implants ◽  
Soft Tissues ◽  
Bone Ingrowth ◽  
Element Model ◽  
Design Guidelines ◽  
Tissue Differentiation ◽  
Bone Implant ◽  
Crestal Bone Loss ◽  
History Of ◽  
Good Agreement

(1) Background: Our aim is to reveal the influence of the geometry designs on biophysical stimuli and healing patterns. The design guidelines for dental implants can then be provided. (2) Methods: A two-dimensional axisymmetric finite element model was developed based on mechano-regulatory algorithm. The history of tissue differentiation around eight selected implants can be predicted. The performance of the implants was evaluated by bone area (BA), bone-implant contact (BIC); (3) Results: The predicted healing patterns have very good agreement with the experimental observation. Many features observed in literature, such as soft tissues covering on the bone-implant interface; crestal bone loss; the location of bone resorption bumps, were reproduced by the model and explained by analyzing the solid and fluid biophysical stimuli and (4) Conclusions: The results suggested the suitable depth, the steeper slope of the upper flanks, and flat roots of healing chambers can improve the bone ingrowth and osseointegration. The mechanism related to solid and fluid biophysical stimuli were revealed. In addition, the model developed here is efficient, accurate and ready to extend to any geometry of dental implants. It has potential to be used as a clinical application for instant prediction/evaluation of the performance of dental implants.

scholarly journals EARLY CRESTAL BONE STABILITY AROUND SUPRACRESTALY PLACED DENTAL IMPLANTS. A CASE SERIES

2019 ◽  
Vol 29 (2) ◽  
pp. 61-64
Author(s):  
Saulius Žukauskas ◽  
Algirdas Puišys ◽  
Paulius Andrijauskas ◽  
Linas Zaleckas ◽  
Tomas Linkevičius
Keyword(s):  
Dental Implants ◽  
Soft Tissues ◽  
Bone Remodelling ◽  
Case Series ◽  
Lower Jaw ◽  
Crestal Bone Loss ◽  
Metal Ceramic ◽  
Key Factor ◽  
The Mean ◽  
Implant Treatment

Stability of crestal bone around dental implants is a major concern for oral surgeons and dentists. It is a key factor for success of dental implant treatment. Crestal bone is more prevented from resorption when surrounding tissues are thicker. Aim of the study – to find out the mean of crestal bone loss around supracrestally placed dental implants with matching platform in vertically thick soft tissues. The final patient sample included 34 patients (17 female and 17 male), who received 34 two piece dental implants in total. All 34 implants integrated successfully as evaluation under implant success criteria was applied. Implants were restored by single-unit crowns, using metal-ceramic prostheses. After 1 year thick soft tissues maintain stable crestal bone around dental implants in lower jaw. Minor bone resorption of 0.28 ± 0.36 mm mm could be seen during early bone remodelling phase.

Experimental and Finite Element Comparaison of Various Joint Fixation Designs

1999 ◽  
Author(s):  
O. Patenaude ◽  
A. Shirazi-Adl ◽  
M. Dammak
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Bone Ingrowth ◽  
Element Model ◽  
Bone Implant ◽  
Combined Loads ◽  
Pull Out ◽  
Initial Fixation ◽  
Fixation Stability ◽  
Friction Models

Abstract The short- and long-term success of tibial cementless implants depends on the initial fixation stability provided primarily by posts and screws. Excessive relative motions at the bone-implant interface are known to inhibit bone ingrowth and, hence, biologic fixation. In this work, the performance of a number of fixation configurations under static and fatigue combined loads (i.e., compression plus shear) is investigated both experimentally and numerically. These results will permit both to compare different fixation types and to serve to validate a 3D finite element model that incorporates the measured nonlinear bone-implant friction and posts/screws pull-out tests. Once validated, the finite element model is also used to study the effect of different bone-implant friction models for porous coated posts and plate and of loading order of application on predictions.

scholarly journals Development of Simulation Based p-Multipliers for Laterally Loaded Pile Groups in Granular Soil Using 3D Nonlinear Finite Element Model

2020 ◽  
Vol 11 (1) ◽  
pp. 26
Author(s):  
Muhammad Bilal Adeel ◽  
Muhammad Asad Jan ◽  
Muhammad Aaqib ◽  
Duhee Park
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Design Guidelines ◽  
American Petroleum Institute ◽  
Winkler Foundation ◽  
Group Effect ◽  
Pile Groups ◽  
Element Analysis ◽  
Laterally Loaded Pile ◽  
Laterally Loaded

The behavior of laterally loaded pile groups is usually accessed by beam-on-nonlinear-Winkler-foundation (BNWF) approach employing various forms of empirically derived p-y curves and p-multipliers. Averaged p-multiplier for a particular pile group is termed as the group effect parameter. In practice, the p-y curve presented by the American Petroleum Institute (API) is most often utilized for piles in granular soils, although its shortcomings are recognized. In this study, we performed 3D finite element analysis to develop p-multipliers and group effect parameters for 3 × 3 to 5 × 5 vertically squared pile groups. The effect of the ratio of spacing to pile diameter (S/D), number of group piles, varying friction angle (φ), and pile fixity conditions on p-multipliers and group effect parameters are evaluated and quantified. Based on the simulation outcomes, a new functional form to calculate p-multipliers is proposed for pile groups. Extensive comparisons with the experimental measurements reveal that the calculated p-multipliers and group effect parameters are within the recorded range. Comparisons with two design guidelines which do not account for the pile fixity condition demonstrate that they overestimate the p-multipliers for fixed-head condition.

scholarly journals Macrophagic Inflammatory Response Next to Dental Implants with Different Macro- and Micro-Structure: An In Vitro Study

2021 ◽  
Vol 11 (12) ◽  
pp. 5324
Author(s):  
Maria Menini ◽  
Francesca Delucchi ◽  
Domenico Baldi ◽  
Francesco Pera ◽  
Francesco Bagnasco ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
Dental Implants ◽  
In Vitro Study ◽  
Titanium Implants ◽  
Implant Surface ◽  
Bone Implant ◽  
Optimal Outcomes ◽  
Negative Controls ◽  
Inflammatory Effect

(1) Background: Intrinsic characteristics of the implant surface and the possible presence of endotoxins may affect the bone–implant interface and cause an inflammatory response. This study aims to evaluate the possible inflammatory response induced in vitro in macrophages in contact with five different commercially available dental implants. (2) Methods: one zirconia implant NobelPearl® (Nobel Biocare) and four titanium implants, Syra® (Sweden & Martina), Prama® (Sweden & Martina), 3iT3® (Biomet 3i) and Shard® (Mech & Human), were evaluated. After 4 h of contact of murine macrophage cells J774a.1 with the implants, the total RNA was extracted, transcribed to cDNA and the gene expression of the macrophages was evaluated by quantitative PCR (qPCR) in relation to the following genes: GAPDH, YWHAZ, IL1β, IL6, TNFα, NOS2, MMP-9, MMP-8 and TIMP3. The results were statistically analyzed and compared with negative controls. (3) Results: No implant triggered a significant inflammatory response in macrophages, although 3iT3 exhibited a slight pro-inflammatory effect compared to other samples. (4) Conclusions: All the samples showed optimal outcomes without any inflammatory stimulus on the examined macrophagic cells.

Osteoclast and osteoblast response to strontium-doped struvite coatings on titanium for improved bone integration

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Claus Moseke ◽  
Katharina Wimmer ◽  
Markus Meininger ◽  
Julia Zerweck ◽  
Cornelia Wolf-Brandstetter ◽  
...  
Keyword(s):  
Bone Ingrowth ◽  
Osteoclast Differentiation ◽  
Inhibitory Effect ◽  
Osteoclast Formation ◽  
Strontium Nitrate ◽  
Bone Implant ◽  
Electrochemically Deposited ◽  
Bone Integration ◽  
Titanium Substrates

AbstractTo develop implants with improved bone ingrowth, titanium substrates were coated with homogeneous and dense struvite (MgNH4PO4·6H2O) layers by means of electrochemically assisted deposition. Strontium nitrate was added to the coating electrolyte in various concentrations, in order to fabricate Sr-doped struvite coatings with Sr loading ranging from 10.6 to 115 μg/cm2. It was expected and observed that osteoclast activity surrounding the implant was inhibited. The cytocompatibility of the coatings and the effect of Sr-ions in different concentrations on osteoclast formation were analyzed in vitro. Osteoclast differentiation was elucidated on morphological, biochemical as well as on gene expression level. It could be shown that moderate concentrations of Sr2+ had an inhibitory effect on osteoclast formation, while the growth of osteoblastic cells was not negatively influenced compared to pure struvite surfaces. In summary, the electrochemically deposited Sr-doped struvite coatings are a promising approach to improve bone implant ingrowth.

scholarly journals Fatigue Modeling and Numerical Analysis of Re-Filling Probe Hole of Friction Stir Spot Welded Joints in Aluminum Alloys

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2171
Author(s):  
Armin Yousefi ◽  
Ahmad Serjouei ◽  
Reza Hedayati ◽  
Mahdi Bodaghi
Keyword(s):  
Experimental Data ◽  
Tensile Strength ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Fatigue Behavior ◽  
Element Model ◽  
Plastic Strain Amplitude ◽  
Friction Stir ◽  
Probe Hole ◽  
Good Agreement

In the present study, the fatigue behavior and tensile strength of A6061-T4 aluminum alloy, joined by friction stir spot welding (FSSW), are numerically investigated. The 3D finite element model (FEM) is used to analyze the FSSW joint by means of Abaqus software. The tensile strength is determined for FSSW joints with both a probe hole and a refilled probe hole. In order to calculate the fatigue life of FSSW joints, the hysteresis loop is first determined, and then the plastic strain amplitude is calculated. Finally, by using the Coffin-Manson equation, fatigue life is predicted. The results were verified against available experimental data from other literature, and a good agreement was observed between the FEM results and experimental data. The results showed that the joint’s tensile strength without a probe hole (refilled hole) is higher than the joint with a probe hole. Therefore, re-filling the probe hole is an effective method for structures jointed by FSSW subjected to a static load. The fatigue strength of the joint with a re-filled probe hole was nearly the same as the structure with a probe hole at low applied loads. Additionally, at a high applied load, the fatigue strength of joints with a refilled probe hole was slightly lower than the joint with a probe hole.

scholarly journals Titanium Wear of Dental Implants from Placement, under Loading and Maintenance Protocols

2021 ◽  
Vol 22 (3) ◽  
pp. 1067
Author(s):  
Georgios Romanos ◽  
Gerard Fischer ◽  
Rafael Delgado-Ruiz
Keyword(s):  
Adverse Effects ◽  
Inflammatory Response ◽  
Dental Implants ◽  
Soft Tissues ◽  
Loading Conditions ◽  
Material Change ◽  
Implant Placement ◽  
Implant Abutment ◽  
Hard Tissues ◽  
Titanium Nanoparticles

The objective of this review was to analyze the process of wear of implants leading to the shedding of titanium particles into the peri-implant hard and soft tissues. Titanium is considered highly biocompatible with low corrosion and toxicity, but recent studies indicate that this understanding may be misleading as the properties of the material change drastically when titanium nanoparticles (NPs) are shed from implant surfaces. These NPs are immunogenic and are associated with a macrophage-mediated inflammatory response by the host. The literature discussed in this review indicates that titanium NPs may be shed from implant surfaces at the time of implant placement, under loading conditions, and during implant maintenance procedures. We also discuss the significance of the micro-gap at the implant-abutment interface and the effect of size of the titanium particles on their toxicology. These findings are significant as the titanium particles can have adverse effects on local soft and hard tissues surrounding implants, implant health and prognosis, and even the health of systemic tissues and organs.

scholarly journals Ovarian epithelioid angiosarcoma complicating pregnancy: a case report and review of the literature

2021 ◽  
Vol 49 (5) ◽  
pp. 030006052110196
Author(s):  
Xiaotong Peng ◽  
Zhi Duan ◽  
Hongling Yin ◽  
Furong Dai ◽  
Huining Liu
Keyword(s):  
Adverse Events ◽  
Soft Tissues ◽  
Malignant Tumors ◽  
Cystic Teratoma ◽  
Abdominal Distension ◽  
Epithelioid Angiosarcoma ◽  
History Of ◽  
New Ideas ◽  
The Right ◽  
Clinical Awareness

Epithelioid angiosarcoma is a rare and highly aggressive soft tissue angiosarcoma most commonly arising in the deep soft tissues. Given that abundant vascular cavities anastomose with each other, most angiosarcomas prone to metastasis recur quickly, and the overall prognosis is poor. We report a 25-year-old woman at 24 weeks’ gestation who presented with a 1-month history of abdominal distension. Ultrasonography suggested a mass in the right adnexa, and she underwent two operations owing to uncontrolled intraperitoneal bleeding with progressive anemia. The right ovarian tumor and right adnexa were removed successively. Biopsy yielded a diagnosis of primary epithelioid angiosarcoma with mature cystic teratoma. The patient died from uncontrolled progressive bleeding 1 week after the second operation. This case revealed that epithelial angiosarcoma is a highly malignant endothelial cell tumor. The results of surgery and chemoradiotherapy tend to be poor, and the recurrence rate is high. The purpose of this study is to raise clinical awareness of epithelial angiosarcoma and its adverse events and to provide new ideas for the treatment of these adverse events. Immunohistochemical staining of pathological specimens can facilitate diagnosis. Pregnancy with malignant tumors may lead to rapid disease progression, extensive lesions, and a poor prognosis.

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