J Adv Prosthodont.  2017 Feb;9(1):14-21. 10.4047/jap.2017.9.1.14.

The influence of the number and the type of magnetic attachment on the retention of mandibular mini implant overdenture

• Lee E
• Shin SY

• KMID: 2368207
• DOI: http://doi.org/10.4047/jap.2017.9.1.14

Abstract

PURPOSE
The aim of this study was to compare the retention of mini implant overdenture by the number, the type of magnetic attachment, and the directions of applied dislodging force.
MATERIALS AND METHODS
The experimental groups were designed by the number and type of magnetic attachment. Twenty samples were tested with Magden implants. Each attachment was composed of the magnet assembly in overdenture sample and the abutment keeper in a mandibular model. Dislodging forces were applied to the overdenture samples (50.0 mm/min) in 3 directions. The loading was repeated 10 times in each direction. The values of dislodging force were analyzed statistically using SPSS at 95% level of confidence.
RESULTS
The retentive force of group 2 was greater than that of group 1 in both types of attachment in every direction (P < .05). Oblique retentive force of flat type magnetic attachment was higher than that of cushion type attachment in both groups (P < .05). In group 1, oblique retentive force showed the highest and anterior-posterior retentive force showed the lowest value in both attachment types (P < .05). In group 2, both types of attachment showed the lowest retentive force with anteriorposterior direction of dislodging force (P <.05).
CONCLUSION
Proper retentive properties for implant overdenture were obtained, regardless of the number and type of magnetic attachment. In both types of magnetic attachment, the greater retentive force was attained with more implants. Oblique retentive force of flat type magnetic attachment was greater than that of cushion type. Among all subgroups, anterior-posterior retentive force was the lowest among three different directions of dislodging force.

Keyword

Overdenture; Dental mini implants; Magnets; Precision attachment

MeSH Terms

Denture, Overlay*

Figure

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  Fig. 1 Two experimental models with two and four implants placed in the interforamen area of mandible. (A) group 1, (B) group 2.

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  Fig. 2 Magnetic attachment overdenture sample seated on a mandibular model with nuts and bolts securely fastened.

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  Fig. 3 Comparison of retentive force according to the number of implant.

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  Fig. 4 Comparison of retentive force according to the type of magnetic attachment.

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  Fig. 5 Comparison of retentive force according to vertical (V), oblique (O), anterior-posterior (AP) directions.

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