Effects of Cusp Inclination and Occlusal Table Dimensions on the Loading on Implant Systems and Simulated Bone

Occlusal surface design is an important factor for controlling force magnitude and direction on implant components and supporting bone. It has been recommended that reducing cuspal inclination and occlusal table dimension is beneficial to the long-term success of the implants and bone. The appropriate superstructure design, including the occlusal surface design of cuspal inclination and the occlusal table dimensions in single-implant restorations, needs to be investigated in an attempt to understand this influence on occlusal load and bone. This study demonstrates a method to apply quantified axial forces to the four different occlusal design models – model one (30-degree cusp inclination with 6-mm occlusal table dimension), model two (30-degree cusp inclination with 3- mm occlusal table dimension), model three (10-degree cusp inclination with 6- mm occlusal table dimension), and model four (10-degree cusp inclination with 3-mm occlusal table dimension) by using an Instron universal testing system to simulate implant-supported single crowns and the supporting bone. Static loads from 50 N to 250 N were applied for 15 seconds and recorded. The applied forces were loaded on two loading sites; the central area and 2 mm buccally of the occlusal inclined plane. Data were analysed to compare the maximum principal strains (microstrains) registered by strain gauges in the buccal and lingual areas of the bone simulated model. This study has shown that there are differences between the four occlusal design models. Loading on the central area of the occlusal specimens caused a significant difference in mean maximum principal strains compared with the 2-mm buccal loading of the occlusal specimens. Under loading applied at 2 mm, the highest mean maximum principal strain was seen in the model one, followed by model three and two. The lowest was presented in model four. Univariate Analysis of Variance (ANOVA) with post hoc test comparing the maximum principal strains (microstrains) for four different occlusal design specimens indicated a significant difference of the maximum principal strains (microstrains) between model one, two, three, and four, when an applied axial loading at 2 mm buccal on the inclined plane with strain gauges attached on the bone simulated model (p = 0.000). The results from this study suggest that cusp inclination and occlusal table dimension significantly affect the magnitude of forces transmitted to implant supported prostheses, which would have an effect on surrounding bone strains of dental implants when occlusal loads are applied in the clinical situations. The occlusal table dimension seems to play a more important role than cusp inclination, although the cusp inclination is still a factor to be considered. Moreover, combination of the two factors, cusp inclination and occlusal table dimension, significantly affects the magnitude of forces transmitted to implant supported prostheses

Biomaterial based modulation of macrophage polarization: a review and suggested design principles

Macrophages have long been known for their phagocytic capabilities and immune defence; however, their role in healing is being increasingly recognized in recent years due to their ability to polarize into pro-inflammatory and anti-inflammatory phenotypes. Historically, biomaterials were designed to be inert to minimize the host response. More recently, the emergence of tissue engineering and regenerative medicine has led to the design of biomaterials that interact with the host through tailored mechanical, chemical and temporal characteristics. Due to such advances in biomaterial functionality and an improved understanding of macrophage responses to implanted materials, it is now possible to identify biomaterial design characteristics that dictate the host response and contribute to successful tissue integration. Herein, we begin by briefly reviewing macrophage cell origin and the key cytokine/chemokine markers of macrophage polarization and then describe which responses are favorable for both replacement and regenerative biomaterials. The body of the review focuses on macrophage polarization in response to inherent cues directly provided by biomaterials and the consequent cuesthat result from events related to biomaterial implantation. To conclude, a section on potential design principles for both replacement and regenerative biomaterials is presented. An in depth understanding of biomaterial cues to selectively polarize macrophages may prove beneficial in the design of a new generation of ‘immuno-informed’ biomaterials that can positively interact with the immune system to dictate a favorable macrophage response following implantation

Effect of the Location of Dental Mini-Implants on Strain Distribution under Mandibular Kennedy Class I Implant-Retained Removable Partial Dentures

Purpose. To investigate the effect of minidental implant location on strain distributions transmitted to tooth abutments and dental minidental implants under mandibular distal extension removable partial denture. Materials and Methods. A mandibular Kennedy Class I distal extension model missing teeth 35–37 and 45–47 was constructed. Six dental mini-implants were placed at positions A, B, and C, where position A was 6.5 mm distal to the abutment teeth with 5 mm between each position. Fourteen uniaxial strain gauges were bonded on the model at the region of dental mini-implant and abutment (first premolar). Four groups were designated according to the location of the mini-implants. A load of 150 N and 200 N was applied using an Instron testing machine. Loadings consisted of bilateral and unilateral loading. Comparisons of the mean microstrains among all strain gauges in all situations were analyzed. Results. Variation in mini-implant locations induced local strains in different areas. Strains at the tooth abutment were significantly decreased in the group in which implants were placed mesially. Strains around the mini-implants showed different patterns when loaded with different loading conditions. The group in which implants were placed distally showed the lowest strains compared to other groups. Conclusion. Mesially placed mini-implants showed the lowest strain around abutment teeth, while a distally-placed mini-implants presented the lowest strain around mini-implants themselves. Under favorable biting force, mini-implant is an option to assist mandibular distal extension removable partial denture. Mesially placed mini-implants are recommended when the abutment has periodontally compromised conditions and a distally placed mini-implant when periodontal conditions are stable

Loading of a single implant in simulated bone

This study investigated the effect of occlusal design on the strain developed in simulated bone of implant-supported single crown models. Triaxial strain gauges were attached at the cervical area of each model. Occlusal design, load location, and magnitude were examined to determine the maximum axial principal strains (με) of four occlusal designs: 30-degree cusp inclination with 4- and 6-mm occlusal table dimensions and a 10-degree cusp inclination with 4- and 6-mm occlusal table dimensions. Statistical differences were found for peak average maximum principal strains between each occlusal design when the applied load was directed along the central fossa and 2 mm buccal to the central fossa along the inclined plane, with strain gauges attached at the cervicobuccal (P < .001) and cervicolingual (P ≤ .001) aspects. In all loading conditions, the 30-degree cusp inclination and 6-mm occlusal table dimension consistently presented the largest strains compared with the other occlusal designs. A reduced cusp inclination and occlusal table dimension effectively reduced experimental bone strain on implant-supported single crowns. The occlusal table dimension appeared to have a relatively more important role than cusp inclination.4 page(s

Effect of particle size of fully porous-coated (FPC) implants on osseointegration

This paper aims at providing a preliminary understanding in biomechanics with respect to the effect of the particle size of Fully Porous-Coated (FPC) dental implant on osseointegration. 2D multiscale finite element models are created for a typical dental implantation setting. Under a certain mastication force (<200N), a global response is first obtained from a macro-scale model (without considering morphological details on the coated surface), and then it is transferred to micro-scale models (with coated surface morphology details in three different particle sizes). An equivalent strain is analyzed to investigate the effect of particle size of the FPC materials on osseointegration and initiation of bone remodelling. The result reveals that increasing particle sizes has a significant effect on biomechanical and bone remodelling responses.4 page(s

PEEK Biomaterial in Long-Term Provisional Implant Restorations: A Review

Polyetheretherketone (PEEK) has become a useful polymeric biomaterial due to its superior properties and has been increasingly used in dentistry, especially in prosthetic dentistry and dental implantology. Promising applications of PEEK in dentistry are dental implants, temporary abutment, implant-supported provisional crowns, fixed prosthesis, removable denture framework, and finger prosthesis. PEEK as a long-term provisional implant restoration has not been studied much. Hence, this review article aims to review PEEK as a long-term provisional implant restoration for applications focusing on implant dentistry. Articles published in English on PEEK biomaterial for long-term provisional implant restoration were searched in Google Scholar, ScienceDirect, PubMed/MEDLINE, and Scopus. Then, relevant articles were selected and included in this literature review. PEEK presents suitable properties for various implant components in implant dentistry, including temporary and long-term provisional restorations. The modifications of PEEK result in wider applications in clinical dentistry. The PEEK reinforced by 30–50% carbon fibers can be a suitable material for the various implant components in dentistry

Effect of fully porous-coated (FPC) technique on osseointegration of dental implants

This paper provides a preliminary understanding in biomechanics with respect to a fully-porous-coated (FPC) dental implant. A 2D multiscale finite element model is created for a typical dental implantation setting. Under a certain mastication force (<200N), a global response is first obtained from a macro-scale model (without coated surface morphology details), and then it is transferred to a micro-scale model (with coated surface morphology details), which allows determining a local biomechanical field. To facilitate the study in bone remodelling, strain energy density and equivalent strain are analysed respectively. Different porosities of coating are taken into account in this study to investigate the effect of FPC materials on these typical remodelling stimuli. The results evidently reflect the osseointegrative benefits generated from surface coating. The result reveals that increasing in particle sizes has significant effect on biomechanical response.4 page(s

Finite element based bone remodeling and resonance frequency analysis for osseointegration assessment of dental implants

Finite Element Analysis (FEA) has been extensively used in design of new prostheses for characterizing biomechanical responses induced in human body. Dental implant, as one of such typical devices, has undergone a rapid development and clinical applications over the last two decades, where FEA has played an important role. One challenge faced by dental profession, however, is the way to assess the oral bone&#039;s osseointegration and remodeling in peri-implant region post surgery. Biomechanically, implantation largely changes local oral environment, subsequently resulting in bone apposition or resorption to adapt such a mechanical change. It is thus of significant interest to relate the bone remodeling to biomechanical responses in a non-invasive way. In this paper, we assess the change in the resonance frequency (or namely natural frequency) in line with the remodeling results from a time-dependent three-dimensional finite element simulation. A quantitative comparison was made against the resonance frequencies measured from the clinical follow-ups. The comparison demonstrated a satisfactory agreement between the developed bone remodeling simulation and clinical data, thus validating the computational prediction