Morphological and structural characteristics of orthodontic mini-implants

  • S. AlSamak
  • E. Bitsanis
  • M. Makou
  • G. Eliades
Original article



The purpose of this study was to investigate the geometric characteristics, composition, microstructure, and pullout strength of commercially available orthodontic mini-implants.

Material and methods

The mini-implants used were AbsoAnchor®, Dual-Top™ JA, Spider Screws® K1, and Vector-TAS™. The geometric features were measured by optical microscopy. Surface texture and elemental composition were examined by scanning electron microscopy and energy dispersive X-ray microanalysis. Surface 3D roughness was estimated by optical profilometry, and pullout strength measured in artificial bone blocks with two bone densities.


The AbsoAnchor® showed the highest intra-osseous surface area, followed by the Dual-Top™, Spider Screw®, and Vector-TAS™. The mini-implants were composed of a Ti6Al4V alloy. The Vector-TAS™ had the highest oxygen and phosphorus content with the most homogeneous surface texture. No significant differences were detected in amplitude surface roughness parameters (Sa, Sz) between the implants. However, differences existed in hybrid (Sdr, Sds) and functional (Sci) parameters. AbsoAnchor® achieved the highest pullout strength, followed by the Dual-Top™, Spider Screw®, and Vector-TAS™, with highest values in the high density group. The intra-osseous surface area of mini-implants showed a positive correlation with pullout strength, especially in the high density group.


All the mini-implants tested were made of Ti6Al4V alloy. Significant differences were found in the surface area of the threaded parts. The significant differences documented in 3D surface roughness parameters (hybrid and functional) and pullout strength may anticipate variations in their clinical performance.


Orthodontic mini-implants Orthodontic anchorage Composition Surface roughness Pullout strength 

Morphologische und strukturelle Merkmale kieferorthopädischer Mini-Implantate



Zweck der vorliegenden Studie war die Erforschung der geometrischen Merkmale, der Zusammensetzung, der Mikrostruktur und Ausreißfestigkeit von handelsüblichen kieferorthopädischen Mini-Implantaten.

Materialien und Methoden

Bei den verwendeten Mini-Implantaten handelte es sich um AbsoAnchor®, Dual-Top™ JA, Spider Screws® K1 und Vector-TAS™. Die Messung der geometrischen Merkmale erfolgte mittels optischer Mikroskopie. Die Untersuchung der Oberflächenbeschaffenheit und der elementaren Zusammensetzung erfolgte mittels Rasterelektronenmikroskopie und energiedispersiver Röntgen-Mikroanalyse. Die 3D-Rauheit der Oberfläche wurde mittels optischer Profilometrie geschätzt, und die Ausreißfestigkeit wurde in künstlichen Knochenblöcken mit zwei verschiedenen Knochendichten gemessen.


AbsoAnchor® zeigte die höchste intraossäre Oberfläche, gefolgt von Dual-Top™, Spider Screw® und Vector-TAS™. Die Mini-Implantate bestanden aus einer Titan-Aluminium-Legierung (Ti6Al4V). Vector-TAS™ wies den höchsten Sauerstoff- und Phosphorgehalt sowie die homogenste Oberflächenstruktur auf. Zwischen den Implantaten wurden keine signifikanten Unterschiede hinsichtlich der Amplituden der Parameter für die Oberflächenrauheit (Sa, Sz) festgestellt. Es bestanden jedoch Unterschiede zwischen den Hybridparametern (Sdr, Sds) und den funktionalen Parametern (Sci). AbsoAnchor® erreichte die höchsten Werte für die Ausreißfestigkeit, gefolgt von Dual-Top™, Spider Screw® und Vector-TAS™, sowie die höchsten Werte in der Versuchsgruppe mit der hohen Knochendichte. Die intraossären Oberflächen der Mini-Implantate waren insbesondere in der Gruppe mit hoher Knochendichte positiv mit der Ausreißfestigkeit korreliert.


Alle getesteten Mini-Implantate bestanden aus einer Ti6Al4V-Legierung. Hinsichtlich der Oberflächen der Gewindeteile wurden signifikante Unterschiede festgestellt. Die signifikanten Unterschiede, die sich hinsichtlich der Parameter für die 3D-Oberflächenrauheit (hybrid und funktional) sowie der Ausreißfestigkeit ergeben, könnten auf Unterschiede im Leistungsverhalten dieser Implantate bei der klinischen Anwendung verweisen.


Kieferorthopädische Mini-Implantate Kieferorthopädische Verankerung Zusammensetzung Oberflächenrauheit Ausreißfestigkeit 



This study was supported by a grant (Ref: 1088/2006–2007) from the Greek State Scholarships Foundation (IKY).


Die vorliegende Studie wurde durch ein Forschungsstipendium (Aktenzeichen: 1088/2006–2007) der griechischen staatlichen Studienstiftung (IKY) unterstützt.

Conflict of interest

The corresponding author states that there are no conflicts of interest.


Der korrespondierende Autor gibt an, dass kein Interessenkonflikt besteht.


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Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  1. 1.Department of OrthodonticsUniversity of Athens School of DentistryAthensGreece
  2. 2.Department of BiomaterialsUniversity of Athens School of DentistryAthensGreece

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