Mandibular Overdenture Retained by Shiner Magnets
The components to augment the Shiner magnets are listed from left: keeper replica for mast cast; processing piece; impression piece; and metal o-ring spacer.
The Shiner mini magnets are on the left and the regular size are on the right. The mini size measures 2.4 mm vertically and '3.9 mm in diameter. The regular size is 3.4 mm in height and 5.5 mm in diameter.
The action between the actual magnet and the housing allows slight movement of the prosthesis. The magnet remains connected to the keeper, which eliminates air gaps and the "snap back" effect.
This graph illustrates how the loss of intimate contact between magnet and keeper diminishes available retention.
This test instrument indicates that the Shiner regular magnet can hold 1.5 Ibs of weight bars. The mini size has approximately 30% less retention.
The top portion of the diagram illustrates the complete armamentarium for the Core-Vent threaded stainless steel keeper system. The bottom half shows titanium stainless steel keepers for the Core-Vent cementable system.
Components and part numbers are shown for the titanium stainless steel keepers in the Core-Vent threaded system.
Healing abutments are secured to interim period.
The patient's existing denture is modified by removing acrylic from the tissue side to accept the five healing abutments. A soft liner material (Coe Super Soft, Coe Inc.) is used to refit the denture to the abutments.
A hex driver is secured to the titanium stainless steel combination keeper.
Keepers are screwed into fixtures with perio-pack around the perimeter to aid in tissue healing.
All keepers are secured to implant fixtures with the hex driver and checked clinically and radiographically for fit.
Impression pieces are secured to keepers using the center hole plug.
The outer rim of the keeper matches perfectly with the impression coping. The two components are held together with a pressure fit. The intimate fit between these two components is a check point for total accuracy
This master cast has the keeper replicas intact. All replicas must be cleaned and air dried for maximum retention of black processing males.
Black processing males are placed; teeth are selected (Bioform lPN, Dentsply Int.); and a full wax setup is completed. Usually the teeth in the areas of the magnets must be hollow ground.
After the wax try-in has been ver-ified, it is then flasked and boiled out in the usual manner.
After boil-out, the processing male at the top is seated down over the a-ring spacer to the keeper replica in the master cast. This metal spacer provides room for the clinician to adjust the position of the magnet as needed. The restoration is now packed with Lucitone 199.
This is a view of the finished and polished overdenture with the processing males intact. Note the appearance of the acrylic at the junction of the attachment.
This metal tool has a magnet hole configuration at one end and processing piece prongs at the other.
Only after the prosthesis is completely polished should the males be carefully backed out with the metal tool.
This schematic diagram shows the magnet driver, magnet, and matching void created by the processing pIece.
Magnets are carefully screwed into threaded sites. Do not force the magnet into the socket. If it does not screw in easily, it must be backed out and started again.
The finished magnet-retained overdenture with all components in place.
The intimate fit of the magnets to the keepers is imperative. Pressure indicator paste (Mizzy Inc.) is applied to the magnets and checked intraorally. Magnets can be adjusted to attain perfect magnet-to-keeper fit.
The finished and polished magnet-retained overdenture.