Factual observations of dynamic bone crushing.

Dynamic bone-crushing, exemplified by the pig bone rib, is characterized thermo-mechanically in relation to the bone's microstructural characteristics. The cortical bone's dominant role consists of shielding the trabecular component by resisting deformation, sustaining high load levels, and ultimately cracking. Here we present a qualitative factual study to show that this behavior is the absolute opposite of its quasi-static counterpart in which the trabecular bone was found to play the dominant role.

Investigating the etiology of non-carious cervical lesions: Novel µCT analysis.

Objectives: The etiology of non-carious cervical lesions (NCCLs) is not fully understood, limiting treatment and prevention. Our aim was to evaluate the effect of mechanical loading and acid exposure on the cervical tooth region using a random spectrum loading model that simulates the nature of oral mastication.

Methods: Thirty extracted human premolars were divided into three experimental groups: 1) unloaded teeth immersed in acid (erosion group: Er), 2) loaded teeth immersed in acid (erosion with spectrum loading group: Er-SL), and 3) loaded teeth immersed in distilled water (spectrum loading group: SL).

Modelling the resonant frequency associated with the spatio-temporal evolution of the bone-dental implant interface.

Dental implant stability is greatly affected by the mechanical properties of the bone-implant interface (BII), and it is key to long-term successful osseointegration. Implant stability is often evaluated using the Resonant Frequency Analysis (RFA) method, and also by the quality of this interface, namely the bone-implant contact (BIC). True to this day, there is a scarcity of models tying BIC, RFA and a spatially and mechanically evolving BII.

Hyperelastic modeling of solid methyl cellulose hydrogel under quasi-static compression.

Constitutive modeling of solid methyl cellulose (MC) hydrogels under quasi-static uniaxial compression is presented for a variety of compositions and test temperatures. Five constitutive models of varying complexity are examined, with the aim to identify the simplest accurate material representation. Due to the viscosity of the gel, the models were calibrated using compression tests only, with restrictions that ensure stability for other loading modes.

A stochastic micro to macro mechanical model for the evolution of bone-implant interface stiffness.

Upon placement of an implant into living bone, an interface is formed through which various biochemical, biological, physical, and mechanical interactions take place. This interface evolves over time as the mechanical properties of peri-implant bone increase. Owing to the multifactorial nature of interfacial processes, it is challenging to devise a comprehensive model for predicting the mechanical behavior of the bone-implant interface.

Design principles of biologically fabricated avian nests.

Materials and construction methods of nests vary between bird species and at present, very little is known about the relationships between architecture and function in these structures. This study combines computational and experimental techniques to study the structural biology of nests fabricated by the edible nest swiftlet Aerodramus fuciphagus on vertical rock walls using threaded saliva. Utilizing its own saliva as a construction material allows the swiftlets full control over the structural features at a very high resolution in a process similar to additive manufacturing.

Impact-induced gelation in aqueous methylcellulose solutions.

Aqueous methylcellulose is an "abnormal" inverse-freezing fluid, which gelates when heated. We ventured to stimulate this phase-transition by mechanical impact, whose resulting shockwaves and local heat could be uptaken by the endothermic gelation. High-speed photography was used to observe this transition in microsecond timescales.

Modeling the effect of osseointegration on dental implant pullout and torque removal tests.

Background: Osseointegration of dental implants is a key factor for their success. It can be assessed either by destructive (eg, pullout or torque extraction), or nondestructive methods (eg, resonant frequency analysis). However, as of today there is a scarcity of models that can relate the outcome of destructive tests to the level of osseointegration.

On stress/strain shielding and the material stiffness paradigm for dental implants.

Background: Stress shielding considerations suggest that the dental implant material's compliance should be matched to that of the host bone. However, this belief has not been confirmed from a general perspective, either clinically or numerically.

Purpose: To characterize the influence of the implant stiffness on its functionality using the failure envelope concept that examines all possible combinations of mechanical load and application angle for selected stress, strain and displacement-based bone failure criteria.

Fatigue of Dental Implants: Facts and Fallacies.

Dental implants experience rare yet problematic mechanical failures such as fracture that are caused, most often, by (time-dependent) metal fatigue. This paper surveys basic evidence about fatigue failure, its identification and the implant's fatigue performance during service. We first discuss the concept of dental implant fatigue, starting with a review of basic concepts related to this failure mechanism.

An Overview of the Mechanical Integrity of Dental Implants.

With the growing use of dental implants, the incidence of implants' failures grows. Late treatment complications, after reaching full osseointegration and functionality, include mechanical failures, such as fracture of the implant and its components. Those complications are deemed severe in dentistry, albeit being usually considered as rare, and therefore seldom addressed in the clinical literature.

The effect of oral-like environment on dental implants' fatigue performance.

Aim And Objectives: The aim of this study was to evaluate the influence of fluid environment mimicking intra-oral conditions on fatigue performance of standard diameter, 3.75-mm implants. Dental implants placed intra-orally are repeatedly submitted to mastication loads in the oral environment, which differ substantially from room-air standard laboratory conditions.

Effect of dental implant diameter on fatigue performance. Part I: mechanical behavior.

Aim: The purpose of this study was to evaluate the effect of the implants' diameter on the mechanical function and load-fatigue performance of dental implants.

Materials And Methods: Three groups of implants with different diameters (3.3 mm, 3.

Effect of dental implant diameter on fatigue performance. Part II: failure analysis.

Purpose: The purpose of this study was to perform fracture mode analysis for in vitro failed implants in order to evaluate the relation between the fracture mode obtained and the implants' fatigue behavior.

Materials And Methods: Eighty fractured dental implants were analyzed after being tested for fatigue performance. A macroscopic failure analysis was performed, which evaluated and located the fracture modes obtained, followed by a microscopic failure analysis comprising a detailed scanning electron microscopy (SEM) fractographic analysis.