Anchorage effects of a palatal osseointegrated implant with different fixation: a finite element study
TL;DR: In this article, the anchorage effect of the osseointegrated implant with different fixation types using finite element analysis was compared using three different implant types: fixation type 1: implant neck in the oral-palatal cortical bone and implant tip in the cancellous bone; fixation type 2: implant head in the nasal-palsalateral bone; and fixation type 3: implant tip projecting into the nasal cavity.
Abstract: The purpose of this study was to compare the anchorage effect of the osseointegrated implant with different fixation types using finite element analysis. Three fixation types were investigated. fixation type 1: implant neck in the oral-palatal cortical bone and implant tip in the cancellous bone; fixation type 2: implant neck in the oral-palatal cortical bone and implant tip in the nasal-palatal cortical bone; fixation type 3: implant neck in the oral-palatal cortical bone and implant tip projecting into the nasal cavity. Three finite element models were constructed. Each consisted of two maxillary second premolars, their associated periodontal ligament (PDL), alveolar bones, palatal bone, palatal implant, and a transpalatal arch. Another model without an implant was used to compare with the previous models. The horizontal force (mesial five N, palatal one N) was loaded at the buccal bracket of each second premolar. The stress was calculated in the PDL and implant surrounding bone. The result showed that the palatal implant could significantly reduce von Mises stress (maximum von Mises stress was reduced 30%) and evenly distribute stress in the PDL. The stress magnitude and distribution in the PDL was almost the same in the three implant models. These results suggest that different implant fixation types have almost the same anchorage effects.
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TL;DR: The Ankylos implant based on the platform switching concept and subcrestal positioning demonstrated better stress-based performance and lower risk of bone overload than the other implant systems evaluated.
Abstract: Statement of problem Load transfer mechanisms and possible failure of osseointegrated implants are affected by implant shape, geometrical and mechanical properties of the site of placement, as well as crestal bone resorption. Suitable estimation of such effects allows for correct design of implant features. Purpose The purpose of this study was to analyze the influence of implant diameter and length on stress distribution and to analyze overload risk of clinically evidenced crestal bone loss at the implant neck in mandibular and maxillary molar periimplant regions. Material and methods Stress-based performances of 5 commercially available implants (2 ITI, 2 Nobel Biocare, and 1 Ankylos implant; diameters of 3.3 mm to 4.5 mm, bone-implant interface lengths of 7.5 mm to 12 mm) were analyzed by linearly elastic 3-dimensional finite element simulations, under a static load (lateral component: 100 N; vertical intrusive component: 250 N). Numerical models of maxillary and mandibular molar bone segments were generated from computed tomography images, and local stress measures were introduced to allow for the assessment of bone overload risk. Different crestal bone geometries were also modelled. Type II bone quality was approximated, and complete osseous integration was assumed. Results Maximum stress areas were numerically located at the implant neck, and possible overloading could occur in compression in compact bone (due to lateral components of the occlusal load) and in tension at the interface between cortical and trabecular bone (due to vertical intrusive loading components). Stress values and concentration areas decreased for cortical bone when implant diameter increased, whereas more effective stress distributions for cancellous bone were experienced with increasing implant length. For implants with comparable diameter and length, compressive stress values at cortical bone were reduced when low crestal bone loss was considered. Finally, dissimilar stress-based performances were exhibited for mandibular and maxillary placements, resulting in higher compressive stress in maxillary situations. Conclusions Implant designs, crestal bone geometry, and site of placement affect load transmission mechanisms. Due to the low crestal bone resorption documented by clinical evidence, the Ankylos implant based on the platform switching concept and subcrestal positioning demonstrated better stress-based performance and lower risk of bone overload than the other implant systems evaluated. (J Prosthet Dent 2008;100:422-431)
440 citations
TL;DR: Although all articles included in this meta-analysis reported success rates of greater than 80 per cent, the factors determining success rates were inconsistent between the studies analysed and this made conclusions difficult.
Abstract: Anchorage is one of the most important elements for successful orthodontic treatment. Traditionally, orthodontics employed teeth and extraoral or intraoral appliances for anchorage, often relying on the patient compliance for its effectiveness. Osseointegrated dental implants were introduced to strengthen anchorage (Wehrbein and Merz, 1998; Wehrbein et al ., 1999; Chen et al ., 2005; Wehrbein and Gollner, 2007), but these implants present with a number of disadvantages that limit routine use.
More recently, different types of skeletal anchorage devices have been introduced, offering potential advantages compared with osseointegrated implants, including: smaller size, which in turn allows more versatile use and reduces amount of surgical intervention necessary, resulting in less patient discomfort; the possibility of immediate loading; lower costs; and ease of removal.
Mini-implants are derived from endosseous implants. They have a conical shape with a head that emerges from the mucosa and that allows connection with orthodontic appliances; mini-implants also contain a smooth transmucosal neck and an endosseous threaded body that can be manufactured with different thread designs and body shapes. Length and diameter vary widely between makes, and the surface is generally smooth, which limits osseointegration.
Mini-plates that are used for orthodontic anchorage are very similar to maxillofacial plates, consisting of a base-plate and fixation screws made of titanium. The shape and size can differ, and the number of fixations can vary from two to five screws.
Mini-screws are made of titanium and are specifically designed for orthodontic anchorage. Their shape is similar to that of mini-implants, but mini-screws are usually smaller (less than 2mm in diameter) and sometimes more tapered. The thread can be self-drilling to allow direct insertion without the use of pre-drilling, which simplifies the insertion technique.
To encompass all of the above-mentioned devices in one definition, we decided to use the term …
69 citations
TL;DR: Investigation of biomechanical interaction between osseointegrated dental implants and bone is numerically investigated through 3D linearly elastic finite-element analyses, when static functional loads occur.
65 citations
TL;DR: The immediate 1-N load did not cause significant changes in the fixation of the mini-implants after 1 and 4 weeks of bone healing, but after 12 weeks, the loaded group had significantly lower RTT values than the unloaded group without compromising the stability of themini- Implants.
57 citations
TL;DR: Numerical simulations revealed that the optimal in-bone positioning depth results from the balance of 2 counteracting effects: cratering phenomena and bone apposition induced by platform-switching configuration, furnishing useful insights and indications for choosing and/or designing threaded osseointegrated implants.
Abstract: This study aimed to investigate the influence of implant design (in terms of diameter, length, and thread shape), in-bone positioning depth, and bone posthealing crestal morphology on load transfer mechanisms of osseointegrated dental implants based on platform-switching concept. In order to perform an effective multiparametric comparative analysis, 11 implants different in dimensions and in thread features were analyzed by a linearly elastic 3-dimensional finite element approach, under a static load. Implant models were integrated with the detailed model of a maxillary premolar bone segment. Different implant in-bone positioning levels were modeled, considering also different posthealing crestal bone morphologies. Bone overloading risk was quantified by introducing proper local stress measures, highlighting that implant diameter is a more effective design parameter than the implant length, as well as that thread shape and thread details can significantly affect stresses at peri-implant bone, especially for short implants. Numerical simulations revealed that the optimal in-bone positioning depth results from the balance of 2 counteracting effects: cratering phenomena and bone apposition induced by platform-switching configuration. Proposed results contribute to identify the mutual influence of a number of factors affecting the bone-implant loading transfer mechanisms, furnishing useful insights and indications for choosing and/or designing threaded osseointegrated implants.
53 citations
References
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Book•
01 May 1993
TL;DR: Contemporary Implant Dentistry, Contemporary Implant Dentistry, this paper, کتابخانه الکرونیک و دیجیتال - آذرسا
Abstract: Contemporary Implant Dentistry , Contemporary Implant Dentistry , کتابخانه الکترونیک و دیجیتال - آذرسا
788 citations
Journal Article•
TL;DR: The results of this study suggest that cancellous bone of higher rather than lower density might ensure a better biomechanical environment for implants, and longer screw-type implants could be a better choice in a jaw with cancellousBone of low density.
Abstract: Purpose A 3-dimensional finite element analysis was performed to evaluate the influence of implant type and length, as well as that of bone quality, on the stress/strain in bone and implant. Materials and methods Two types (screw and cylinder) and 4 lengths (9.2, 10.8, 12.4, and 14.0 mm) of titanium implants were buried in 4 types of bone modeled by varying the elastic modulus for cancellous bone. Axial and buccolingual forces were applied to the occlusal node at the center of the abutment. Results Regardless of load direction, maximum equivalent stress/strain in bone increased with a decrease in cancellous bone density. Under axial load, especially in the low-density bone models, maximum equivalent strain in cancellous bone was lower with the screw-type implant than with the cylinder-type implant. It was also lower with the longer implants than with the shorter implants. Under buccolingual load, equivalent stress/strain was influenced mainly by bone density. Discussion This study confirms the importance of bone quality and its presurgical diagnosis for implant long-term prognosis. Implant length and type can also influence bone strain, especially in low-density bone. Conclusions The results of this study suggest that cancellous bone of higher rather than lower density might ensure a better biomechanical environment for implants. Moreover, longer screw-type implants could be a better choice in a jaw with cancellous bone of low density.
343 citations
TL;DR: The Orthosystem may replace compliance dependent extraoral anchoring aids for orthodontics and makes a bonding of well aligned mandibular dentition and it's use with class II elastics unnecessary.
Abstract: This paper presents the Orthosystem (Institute Straumann, Waldenburg/ Switzerland), a new endosseous orthodontic implant anchor system for palatal anchorage. The Orthosystem may replace compliance dependent extraoral anchoring aids for orthodontics and makes a bonding of well aligned mandibular dentition and it's use with class II elastics unnecessary. The fixture is designed for a one-stage application. It consists of an implant of pure titanium with a surface-treated, screw-shaped endosseous part of 3.3 mm diameter and lengths of 4 and 6 mm. Above the polished transmucosal neck follows as abutment where transpalatal arches made of rigid orthodontic wires (0.032 x 0.032 inch) are fixed by means of a clamp-cap. 6 patients with an angle class II malocclusion were implanted with the 6 mm fixture in the proximal midsagittal region of the palate during a pilot study. The treatment goal was extraction of the first maxillary premolars with subsequent retraction of the frontal dentition under maximal anchorage of the lateral teeth. For the implantation a simple surgical procedure of 10 min length was required while no further invasive action are needed until explantation. This way the strain on the patients was reduced to a minimum. They are now at varying stages of active treatment and the most advanced case is demonstrated here. The clinical and radiological findings after 12 months of treatment comprising 3 months of healing revealed no implant mobility or dislocation, favourable periimplant soft tissue conditions, and no marked mesial movement of the implant supported teeth. The frontal dentition was retracted by 8 mm with space closure occurring in a relatively short treatment period.
246 citations
TL;DR: Bone loading patterns in the vicinity of the implant seem to be very sensitive to bone elastic properties, so finite element models should be integrated correctly in numerical models of in vivo behaviour of oral implants.
Abstract: Finite element models were created to study the stress and strain distribution around a solitary Branemark implant. The influence of a number of clinically relevant parameters was examined: bone-implant interface (fixed bond versus frictionless free contact), bone elastic properties, unicortical versus bicortical implant fixation and the presence of a lamina dura. Bone loading patterns in the vicinity of the implant seem to be very sensitive to these parameters. Hence they should be integrated correctly in numerical models of in vivo behaviour of oral implants. This necessitates the creation of patient-dependent finite element models.
231 citations
TL;DR: Endosseous implants in dogs are used successfully to apply orthodontic and orthopedic forces and not all experimental implants remained firm enough through the initial healing period to be used for anchorage.
Abstract: Endosseous implants in dogs are used successfully to apply orthodontic and orthopedic forces. Not all experimental implants remained firm enough through the initial healing period to be used for anchorage.
192 citations