ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

insertion of provisional restorations during the osseointegration phase of conventional
standard (larger diameter) endosseus implants [2]. The assumption was that mini implants
are unable to provide functional load of implant-supported prostheses [1]. In the
course of time, it was observed that those implants osseointegrated very well clinically
[3]. It became clear that, in combination with a minimally invasive implant insertion
protocol for the mini implants, they could provide a satisfactory prosthodontic rehabilitation
effect [3].
A lot varying mini implant designs are available in the market for the clinical applications.
Depending on the manufacturer, the implants are available in different geometries,
thread configurations (if any) and thread depth.
Hence, it was the purpose of the present study to analyse numerically and experimentally
the biomechanical characteristics of the commercially available mini implants. An
almost complete market overview was intended. Implants’ micromotion as well as the
magnitude and distribution of stresses and strains in the alveolar bone around the implants
were investigated.
3. MATERIALS AND METHODS
3.1 Numerical Analysis
A total of thirteen three-dimensional finite element (FE) models
were developed for the selected commercial mini implants: MDI
Hybrid TM (1.8x10 mm, 1.8x13 mm, 2.1x10 mm, 2.1x13 mm,
2.4x10 mm, 2.4x13 mm, 2.9x10 mm, 2.9x13 mm), Komet MicroPlant
(2.5x15 mm), Sybron Bicortical ® (2.5x13 mm, 2.5x16
mm), K.S.I.-Bauer Schraube (3.0x15 mm, 3.0x18.5 mm). The
geometries of the implants were reconstructed based on µCT
data (SkyScan 1174, SKYSCAN, Belgium) using the selfdeveloped
software ADOR-3D [4]. Following reconstruction of
implant geometries, the data were imported into the FE package
Marc Mentat 2007 (MSC.Software, Santa Ana, CA, USA).
According to their clinical applications, an immediate loading
condition was considered for the numerical analysis of the mini
implant models. Young’s moduli of the different structures were
chosen as follows: 110 GPa for the implants, 20 GPa for cortical
bone, and 1,000 MPa for the cancellous bone. Typically, mini
implants are inserted into the anterior mandibular jaw region,
thus the cortical layers had a thickness of 1.2 mm (Figure 1).
3.2 Experimental Investigations and Measurement Set-up
150 N
30°
Figure 1: Loading direction
and point of force application
of the numerical models.
In this study porcine lower jaw segments (from the jaw angle region) were used as implant
bed. Two specimens were considered for each implant, i.e. totally 26 specimens
were measured. Porcine jaw segments were sawed with continuous lubrication to avoid
excessive heating during the cutting procedure.
Later on, the implants were inserted according to the surgical protocol of the individual
manufacturers. The stability of the specimens within the holder was achieved by em-