Abstract

In terms of the choice of a keeper for a magnetic attachment, there is no choice but to choose a small attractive force type due to limitation of a root anatomy. As a countermeasure for it, arranging two small magnetic attachments in parallel along with the root surface morphology, however, there is no detailed report about position of the keepers.

The purpose of this study is to clarify how the distance between the each keepers affects its attractive force as they are arranged in parallel.

Abstract

The purpose of this study is to demonstrate the resistance force of magnetic attachments against external forces that displace it laterally along the mating face. The resistance and attractive forces during lateral displacement between a magnetic assembly or neodymium magnet and its keeper were measured. The maximum friction force of the Physio Magnet 5213 magnetic attachment was 1.78 N whereas that of neodymium keeper was 0.39 N. It was demonstrated that besides frictional force, the magnetic attraction force contributes towards the overall resistance against external forces that laterally displace the magnetic assembly from its keeper. The magnetic attachment had a smaller attraction force than the maximum static friction. Contrastingly, neodymium magnet combined with the same keeper, upon significant displacement, generated an attraction force that exceeded the maximum static friction force. This is because the magnet’s open circuit system generated an attraction force that restored the magnet to its keeper. Further understanding and utilization of this phenomenon, is significant for development of a new magnetic attachment with a stronger bracing function.

Abstract

The magnetic attachment is made of a neodymium magnet in the magnet assembly, and can demonstrate a small size but strong attractive force. The basic structure of magnetic attachments is the magnetic assembly, which is set on the mucosal surface of denture base, and the keeper, which is attracted to the magnetic assembly and is set in the root cap of the abutment tooth to form the retainer. In addition, the magnetic attachment is applied not only to the removable dentures, but also to maxillofacial prostheses and dental implants, therefore it is a highly versatile retainer. The most important advantage of the magnetic attachment is that it can be used in the root cap type or telescopic crown type according to the clinical conditions of the abutment tooth. As a result, it is possible to preserve abutment teeth with maximized support ability by using either type of them, which is considered to have great clinical advantage. This report is a case study of partial denture prostheses designed with magnetic attachments of the Magno Telescopic crown type for the maxilla and the root cap type for the mandible, which are followed in good condition for a long time.

Abstract

In this case report, a denture was repaired by applying a magnetic attachment after extracting the abutment tooth of a cone crown telescope. The patient was a 76-year-old female. She wore a denture with a cone crown telescope for three missing teeth: the left central incisor, the lateral incisor, and the canine. The second premolar on the left side of the maxilla, one of the abutment teeth, was extracted due to root fracture. Subsequently, a full metal crown with an extracoronal magnetic attachment was affixed to the maxillary left first molar behind the defect. Denture repair was performed by adding a magnetic attachment to the inner surface of the outer crown of the second premolar on the left side of the maxilla to match the keeper of the extracoronal magnetic attachment. The patient was satisfied with using the repaired denture. In addition, by adopting an extra-crown attachment, it was possible to reduce the burden on the abutment tooth.

Abstract

To reconstruct a harmonious craniofacial system, it is essential to maintain an appropriate occlusal vertical dimension(OVD). This clinical report describes the prognosis of a magnetic attachment denture that improved an immediate denture to maintain appropriate OVD and the optimum mandibular position.

As a definitive prosthesis, a removable maxillary overlay denture was fabricated and included a coping type of magnetic attachment, copings, and circumferential clasps.

Nine years after the denture setting, the definitive prosthesis has been used without serious problems, and the magnetic attachment has no clinically significant loss of retention.

Abstract

【Objective】

In recent years, digital dentistry based on computer-aided design and computer-aided manufacturing (CAD/CAM) has become increasingly popular, and the workflow for the fabrication of removable dentures has changed dramatically. This case was used CAD/CAM technology for maxillary conventional overdenture and mandibular implant overdenture (IOD) with magnetic attachments.

【Method】

CAD/CAM dentures were fabricated using DENTCA system (DENTCA Inc., Mitsui Chemical Inc.). On the initial visit, exclusive plastic trays (DENTCA tray, DENTCA Inc.) were used for making definitive impression, determination of vertical dimension, and recording of the centric relation with gothic-arch tracing. On the second visit, 3D printed try-in dentures were placed in the patient’s mouth, occlusion, retention, stability, and esthetics were checked and corrected. On the final visit, CAD/CAM dentures were delivered in the patient’s mouth.

【Results, Discussion】

For maxillary conventional overdenture and mandibular IOD with magnetic attachments using CAD/CAM technology can be fabricated high strength and accuracy prosthesis.