The paper deals with fundamental property
of magnetic line of force and operation principles
of Magnetic sensors and eddy current sensors
which are acted by the magnetic line of force.
Mechanical models of tooth movement are analyzed
based on the past research results.
Useful magnetic sensors and eddy current sensors in the magnetic application in dentistry are surveyed. The paper explains each measuring range, resolution, size and production companies or small-sized SQUID, magneto impedance sensor and Hall-sensor. It is listed up the principle or measurement and the characteristics of displacement sensors, velocity sensors, acceleration sensors and pressure sensors. The paper also suggests relationship between the saliva and the permanent magnet or the magnetic attachment. Present research results of "new tracking systems of jaw movement" by two research groups are Introduced. It is classified five Japanese Patents related the chewing counters in 1993-2000, the key Point of the chewing counter development also describes in the paper.
A magnetic attachment is an excellent retaining device with various benefits. Due to the unique retaining mechanism using "magnetic energy", however, its maximum potential cannot be attained if used based solely on prosthetic concepts proven for conventional flexible and rigid support restorations. For this reason, a design guideline has been developed by classifying the functional roles of magnetic attachments into Type R for retention only, Type SR for support and retention and Type BSR for bracing, retention and support. Further, the practical design chart we have developed, focusing on implant-supported overdentures, based on the guideline has led us to successful treatment outcomes. The guideline and the design chart have demonstrated their effectiveness in prosthetic restoration using the MACS System (Magnetic Attachments of a Cap Shape), a magnetic attachment system having high compatibility with the classification mentioned above. "Universal Support" is the new prosthetic policy we proposed, in which the highest priority is placed on freeing the patients from feelings of inadequacy due to tooth loss. Magnetic attachments have been indicated to be the optimal retaining device for Universal Support restorations.
The property of magnets incorporated in magnetic
assemblies are affected by surrounding environments
i.e. airgap. The purpose of this sturdy was
lo evaluate the effect of the airgap (with
or without keepers) on the attractive force
or magnetic attachments after heating procedures.
5difrerent sized HICOREX SLIM (Hitachi Metals
Ltd), which consisted or the Nd-Fe-B magnet
were used in this study. The results were
1.Magnetic assemblies heated with keeper. Attachments forces remained stable until they were heated at 190 degrees C. The difference of their sizes did not affect their heat-stabilities.
2. Magnetic assemblies heated without keepers. Attractive forces remained stable until they were heated at 120 degrees C. (HICOREX SLIM 4513,4013), 130 degrees C. (HICOREX SLIM 3513), 150 degrees C. (HICOREX SLIM 3013,2513). Magnetic attachments became wider in size, their heat-stabilities dropped.
Several different types of magnetic attachment
have being used together for retention of
the oberdenture in ordinary clinical practice.
Evaluating the retention characteristics
of such magnetic attachments may be very
complex. For analysis of magnetic retention
, it is convenient to represent the retention
characteristics by a simple expression. The
expression is derived here and applied to
each magnetic attachment. Functional efficiency
of various magnetic attachments is also compared
With each other.
Tomokazu Hirano, Kouichi Sugiyama, Yukihiro Mizuno, Fujio Tsuchida* Michio Motonaga* Toshio Hosoi*
Dental laboratory techniques for direct bonding
method, which will solve some of the problems
associated with casting and make full use
of the attachment magnetic property were
investigated in this study. The following
results were obtained using an ultra-precision
finishing film and cover glass cementing
1. Adhesive resin cement can be light-cured through the cover glass.
2. It is possible to obtain a same finish plane between the surface of the adhesive resin cement and the keeper.
3. The smooth surface of the cover glass is transferred to the surface of the adhesive resin cement.
4. The keeper surface can be fabricated without overflow resin cement and scratch.