[The biomechanics of dental implants and dentures] (original) (raw)
Related papers
Three-dimensional finite-element analysis of osseointegrated dental implants
2007
In this paper the biomechanical interaction between osseointegrated dental implants and bone is investigated by numerical simulations. The influence of some mechanical and geometrical parameters on bone stress distributions is highlighted and some risk‐measures relevant to critical overloading are furnished. Load transfer mechanisms of several dental implants are analyzed by means of linearly elastic finite‐element analyses, when static functional loads occur. For a given implant the variation of its performance with the placement is investigated, considering insertions both in mandibular and maxillary molar segments. The mechanical properties of the bone regions (cortical and cancellous) are approximated with those of a type II bone and the geometry of crestal bone loss after a healing period is modelled. Five commercially-available dental implants are analyzed, demonstrating as the optimal choice of an endosseous implant is strongly affected by a number of shape parameters as well...
Evaluation of design parameters of osseointegrated dental implants using finite element analysis
Journal of Oral Rehabilitation, 2002
Finite element analyses were performed for various shapes of dental implant to study effects on stress distribution generated in the surrounding jaw bone and to determine an optimal thread shape for even stress distribution. It was found that the square thread shape filleted with a small radius was more effective on stress distribution than other dental implants used in the analyses. Additional analyses were performed on the implant with the thread shape obtained from previous analyses for varying other design parameters, such as the width of thread end and height of thread for various load directions, to determine the optimal dimensions of the implant. Stress distribution was more effective in the case when the width of thread end and the height of thread were 0AE5p and 0AE46p, respectively, where p is the screw pitch. Then, using the optimal implant thread dimensions determined previously, stress analyses were performed with various screw pitches and implant lengths, to investigate effects on stress distribution and to find the way to reduce the maximum effective stress generated in the jaw bone. Results show that the maximum effective stress decreased not only as screw pitch decreased gradually but also as implant length increased.
2006
of the human mandible is analysed. The ultimate aim of this article is to advance the use of an innovative engineering approach in dental practices, especially in the process of dental implantation. Material and Methods: The FEM and analysis techniques are used to replicate and evaluate the stress profile created within the mandible during the implantation process. Results: The von Mises stress profiles in both cancellous and cortical bone are examined during implant insertion. The applied torque and the insertion stage are found to strongly influence the resulting stress profile within the surrounding jawbone. Conclusions: Through the combination of both dental and engineering expertise, a simplified and efficient modelling technique is developed. This improves the understanding of the biomechanical reaction that the jawbone exhibits due to the insertion of implant. The current research is a pilot study using the FEM to model and simulate the dental implantation process. The assump...
The objective of the present study was to assess the influence of various clinically relevant scenarios on the strain distribution in the biomechanical surrounding of five different dental implant macrogeometries. The biomechanical environment surrounding an implant, i.e., the cortical and trabecular bone, was modeled along with the implant. These models included two different values of the study parameters including loading conditions, trabecular bone elastic modulus, cortical/trabecular bone thickness ratio, and bone loss for five implant designs. Finite element analysis was conducted on the models and strain in the bones surrounding the implant was calculated. Bone volumes having strains in four different windows of 0 -200 , 200-1000 , 1000-3000 , and Ͼ3000 were measured and the effect of each biomechanical variable and their twoway interactions were statistically analyzed using the analysis of variance method. This study showed that all the parameters included in this study had an effect on the volume of bones in all strain windows, except the implant design, which affected only the 0 -200 and Ͼ3000 windows. The two-way interaction results showed that interactions existed between implant design and bone loss, and loading condition, bone loss in the 200-1000 window, and between implant design and loading condition in the 0 -200 window. Within the limitations of the present methodology, it can be concluded that although some unfavorable clinical scenarios demonstrated a higher volume of bone in deleterious strain levels, a tendency toward the biomechanical equilibrium was evidenced regardless of the implant design.
Prosthesis
Dental implant macro- and micro-shape should be designed to maximize the delivery of optimal favorable stresses in the surrounding bone region. The present study aimed to evaluate the stress distribution in cortical and cancellous bone surrounding two models of dental implants with the same diameter and length (4.0 × 11 mm) and different implant/neck design and thread patterns. Sample A was a standard cylindric implant with cylindric neck and V-shaped threads, and sample B was a new conical implant with reverse conical neck and with “nest shape” thread design, optimized for the favorable stress distribution in the peri-implant marginal bone region. Materials and methods: The three-dimensional model was composed of trabecular and cortical bone corresponding to the first premolar mandibular region. The response to static forces on the samples A and B were compared by finite element analysis (FEA) using an axial load of 100 N and an oblique load of 223.6 N (resulting from a vertical lo...
The Effect of Dental Implant Design on Bone Induced Stress Distribution and Implant Displacement
International Journal of Computer Applications, 2013
Dental implants have a great role in changing treatment concepts to edentulous ridges. This paper presents a finite element analysis evaluation of the effect of implant design on the stress distribution induced in bone surrounding the implant and on the micro displacement of the implant of a full arch screw retained cantilevered fixed mandibular restoration, in case of immediate loading. Twelve models were simulated, all composed of four identical interforaminal dental implants and a cantilever overdenture. Two design parameters (the implant diameter and taper) were tested while keeping all other parameters fixed. The simulated 12 implants have 3.2, 3.7, 4.7 and 6 mm diameter with 0, 2 and 5 degrees tapering respectively. Vertical and oblique loads were applied on the right premolar and first molar under model restrain. Results revealed that, increasing implant diameter leads to decreased bone induced stresses and also decreased implant micro displacement and so leading to better initial stability. On the contrary, increasing implant tapering increased bone induced stresses and also increased implant micro displacement.
Micro finite element analysis of dental implants under different loading conditions
Computers in Biology and Medicine, 2018
Osseointegration is paramount for the longevity of dental implants and is significantly influenced by biomechanical stimuli. The aim of the present study was to assess the micro-strain and displacement induced by loaded dental implants at different stages of osseointegration using finite element analysis (FEA). Computational models of two mandible segments with different trabecular densities were constructed using microCT data. Three different implant loading directions and two osseointegration stages were considered in the stress-strain analysis of the bone-implant assembly. The bony segments were analyzed using two approaches. The first approach was based on Mechanostat strain intervals and the second approach was based on tensile/compression yield strains. The results of this study revealed that bone surrounding dental implants is critically strained in cases when only a partial osseointegration is present and when an implant is loaded by buccolingual forces. In such cases, implants also encounter high stresses. Displacements of partially-osseointegrated implant are significantly larger than those of fully-osseointegrated implants. It can be concluded that the partial osseointegration is a potential risk in terms of implant longevity.
Biomechanical Behavior of the Dental Implant Macrodesign
The International journal of oral & maxillofacial implants
The aim of this study was to evaluate the influence of implant macrodesign when using different types of collar and thread designs on stress/strain distributions in a maxillary bone site. Six groups were obtained from the combination of two collar designs (smooth and microthread) and three thread shapes (square, trapezoidal, and triangular) in external hexagon implants (4 × 10 mm) supporting a single zirconia crown in the maxillary first molar region. A 200-N axial occlusal load was applied to the crown, and measurements were made of the von Mises stress (σvM) for the implant, and tensile stress (σmax), shear stress (τmax), and strain (εmax) for the surrounding bone using tridimensional finite element analysis. The main effects of each level of the two factors investigated (collar and thread designs) were evaluated by one-way analysis of variance (ANOVA) at a 5% significance level. Collar design was the main factor of influence on von Mises stress in the implant and stresses/strain ...
Biomechanical dental implants comparison by means of numerical models and nuclear medicine
Modelling in medicine and biology VII, 2007
It is well known that the success or the failure of implants interfaced with bone depends, taking into account a favourable biological reaction, on the structural condition of the biomechanical system constituted by the bone structure and the implant. Knowledge of the strain/stress pattern can allow one to establish if bone maintenance, resorption or addition is more likely to take place. In this work two different kinds of implant supports for overdenture retention were compared by means of FEM: they differed in the number of implants, their dimension, their location ...
Mechanical behaviour of dental implants
Procedia structural integrity, 2016
Dental implants are majority made of titanium, since this material promotes a stable and functional connection between the bone and the surface of the implant. Efforts produced during the chewing cycles may interfere with this union, affecting the process of osseointegration and eventually compromising the stability of the implant. Given the difficulty in working with bone in vivo, in the present study two implant systems were inserted in polymer samples, known as Sawbones, which simulate the structure of trabecular bone. On the experimental side, the performance of the implants was evaluated through fatigue tests. The qualitative analysis of the damage in the structure of the samples was performed using scanning electron microscope images. The study was complemented with the determination and comparison of stress fields and deformations at the Sawbone-implant interface using an analytical model of indentation and the finite element method. The experimental results showed that the performance of the Morse taper implant is greater than the external hexagonal implant when both are tested cyclically in samples of different densities. It was proven that the diameter, length, density and type of implantabutment interface are design variables that affect the behavior of the implants. The numerical results of indentation model are very similar to those obtained by the analytical model. The results of the penetration FEM model have the same tendency as the experimental values and the FEM models and analytical indentation with increasing density of the polymer foam. It can be concluded that, as in foams, the increase of the bone density will induce an increased stability to the implants