Implant supported removable dental prosthesis with magnetic attachment in crossed occlusion: A case report / 대한치과보철학회지

When attempting to restore the oral function of a partially edentulous patient, there are a number of prosthetic treatment options available, depending on the structure of remaining teeth. For example, when only one set of maxillary and mandibular teeth are diagonally in place across from each other, it is difficult to gain stable occlusion. In this case, implants can be put in place at the corresponding edentulous area to achieve balance. By doing so, a stable occlusion can be achieved. For this case report, a patient with crossed occlusion after extraction was treated with maxillary RDP (removable dental prosthesis) and mandibular implant-supported RDP (removable dental prosthesis). Moreover, an implant fixture was placed under the posterior molar of the distal extension base diagonally across from the remaining maxillary teeth. Then, magnetic attachment was implemented. According to the patient who received the treatment, the result was functionally and aesthetically satisfactory.

Study on electrical measurement stress analysis of root attachment overdenture of three different mechanisams / 口腔疾病防治

Objective@#To analyze the stress difference of alveolar bone around the abutment and alveolar ridge of edentulous of three different kinds of root-attachment-supported overdenture under different load conditions, in order to provide a reference for the choice of clinical root attachment. @*Methods @#The occlusal force of overdenture was simulated by electrical resistance strain measurement in vitro. The stress of the alveolar bone, the central part of the mandibular arch and the first molar correspond to the alveolar ridge were measured. The stress difference of 3 kinds of attachment overdenture under different loading conditions were compared and analyzed.@*Results@#Under the same loading condition, all three kinds of overdentures had a certain degree of slip of the denture (magnetic attachment denture) or rotation (3 kinds of attachment dentures). The abutment neck in different parts of the dental arch and alveolar bone, anterior free end edentulous alveolar ridge stress distribution was significantly different. @*Conclusion@# ERA attachment overdenture was the most preferable, followed by the magnetic attachment overdenture. Suitable attachment should be selected based on specific clinical cases.

A study on the changes in attractive force of magnetic attachments for overdenture

PURPOSE: Although magnetic attachment is used frequently for overdenture, it is reported that attractive force can be decreased by abrasion and corrosion. The purpose of this study was to establish the clinical basis about considerations and long term prognosis of overdenture using magnetic attachments by investigating the change in attractive force of magnetic attachment applied to the patients. MATERIALS AND METHODS: Among the patients treated with overdenture using magnetic attachments in Dankook University Dental Hospital, attractive force records of 61 magnetic attachments of 20 subjects who re-visited from July 2013 to June 2014 were analyzed. Dental magnet tester (Aichi Micro Intelligent Co., Aichi, Japan) was used for measurement. The magnetic attachments used in this study were Magfit IP-B Flat, Magfit DX400, Magfit DX600 and Magfit DX800 (Aichi Steel Co., Aichi, Japan) filled with Neodymium (NdFeB), a rare-earth magnet. RESULTS: Reduction ratio of attractive force had no significant correlation with conditional variables to which attachments were applied, and was higher when the maintenance period was longer (P<.05, r=.361). Reduction ratio of attractive force was significantly higher in the subject group in which attachments were used over 9 years than within 9 years (P<.05). Furthermore, 16.39% of total magnetic attachments showed detachment of keeper or assembly. CONCLUSION: Attractive force of magnetic attachment is maintained regardless of conditional variables and reduction ratio increased as the maintenance period became longer. Further study on adhesive material, attachment method and design improvement to prevent detachment of magnetic attachment is needed.

Overdenture with magnetic attachments for a patient with Parkinson's disease: a case report

It is very hard for edentulous patients to satisfy retention and stability with their complete denture. Especially, for patients with systemic diseases such as Parkinson's disease causing involuntary and limited movements, fabricating complete dentures may be challenging to both dentists and patients due to functional limitations. To overcome this problem, overdentures can be used through conserving retained roots. In this case, a 45-year-old male patient had to extract numerous teeth due to dental caries, and at the time of visit he was taking drugs for diabetes and Parkinson's disease for a period of long time. A complete denture was applied to maxilla, and for mandible, an overdenture on two preserved retained roots was applied where its retention and stability were obtained by magnetic attachments. This case reports that overdenture with retained roots improved overall functional limitations.

Clinical application of magnetic attachment in the treatment for dentition defect / 安徽医科大学学报

38 patients with dentition defect in our hospital for magnetic attachment dental treatment were analyzed. At the same time,34 cases of patients with dentition defects were ,being treated with conventional prosthodontics, selected to compare the stability of overdentures and masticatory function with magnetic attachment. The stability of overdentures and masticatory function after restored with magnetic attachment was significantly higher than before(P< 0. 01),while there was no difference after 4 weeks. Cementation language,comfort and appearance satisfaction after 4 weeks were significantly higher than before(P < 0. 05). The stability of overdentures,masticatory function, cementation language,comfort and appearance satisfaction after restored with magnetic attachment was significantly higher than conventional prosthodontics(P < 0. 05). It finally indicated that magnetic attachment had the advanta-ges of comfort,convenience and good effect. The stability of overdentures,masticatory function and application sat-isfaction was superior to conventional prosthodontics,and it had an application prospect.

Stress analysis of magnetic attachment in mandibular complete overdenture supported by nature roots and implants / 吉林大学学报(医学版)

Objective To analyze the stress state of magnetic attachment in mandibular complete overdenture supported by nature roots and implant, and to provide neference for designing of clinical prosthodentics. Methods Three-dimensional finite models (model,Ⅱ,Ⅲ)of three groups of mandibular overdentures depending on the different location of the implant and natural tooth root, placing three pairs of magnetic attachment, were constructed by application of CT scanning,computer photo processing system,and Solidworks finite element model building software.The natural teeth and implant neck bone stress of the models in three groups under different stress were calculated and compared.Results The stress of the bone around the implant in the area of molar teeth in model with both sides of the implants under oblique load (Model Ⅱ)was significantly increased compared with the model with one side of the implant (Model Ⅲ). The supporting bone stress of oblique load was increased compared with the vertical load;among them under the oblique load at one side’ s molar teeth, the stress of the bone around the implant in the area of molar teeth in modelⅠ,modelⅡ and model Ⅲ was increased about 30%, 43%,and 55%.Conclusion When there only one nature teeth remain,two implants should be at least added, one in the area of opposite cuspid, and the other in the area of molar teeth of the same side. The magnetic attachment is better than other kinds of attachment in preventing the damage of abutment when it suffers inclined load.

Case Reports On The Magnetic Retained Overdentures / 대한치과보철학회지

The purpose of this study was to evaluate a cases which was treated with magnetic attachments on the patients in edentulous mandible and maxilla.Author made magnetic overdenture for two patients and then clinical examination were used for evaluation of the function and change in retention during 30months.Patients showed difficulty in oral hygiene care at the beginning but they go used to it soon. It was effective in promotion of denture retention and stability and also gave patient emotionally uplifting psychologic state.This study suggest that magnetic attachment was effective for the treatment of patients presenting a few remaining teeth or teeth under severe caries or mobility.

Corrosion Phenomena Of Magnetic Attachment Used In Oral Environment / 대한치과보철학회지

The purpose of this study was to investigate further the mechanics of failure of magnets used for denture retention. Dyna magnets were retrived from denture that had failed after 34 months of clinical use. The magnets were observed and sectioned in order to analyse with high resolution scanning electron microscope. From this study, corrosion behaviors of used magnetic attachment were analysed. The results were as follows: 1. In Nd-Fe-B based magnetic materials, the erosion-corrosion was started at ununiformed part of stainless steel cover. 2. Corrosion was initiated at weared stainless steel surface and then magnetic materials were spalled by corrosive solution. 3. Spalling was occurred in Nd-Fe-B magnet materials due to corrosion products and then corrosion rate was increased drastically. 4. Corrosion started from ununiformed stainless steel surface as well as welded zone. In conclusion, the failure of magnets may occur by either breakdown of the welding or breakdown of the encapsulating material. So, it is considered that the corrosion problem of dental magnetic materials could be solved to some extent with surface treatment of dental magnetic materials.

Comparison of properties of laser-welded coping keepers and cast coping keepers / 实用口腔医学杂志

objective: To study the properties of keepers treated with different methods. Methods: Eighteen Z 3 magnetic attachments were divided into three groups at random. Cobalt chromium alloy was used for root cap. The keepers in the first group were cast to the caps, those in the second group were welded to the caps by Nd:YAG laser welding apparatus. Keepers in the third group were untreated. Universal testing machine was adopted to measure the breakaway retention of the attachments. The roughness of keeper surfaces was measured by roughness tester. Results: No statistical difference was observed as to the breakaway retention between magnetic attachments and laser welded coping keeper or between those and cast coping keepers. But retention of the keepers in the two groups was slightly lower than that of untreated keepers. Defects of pits were found on the surfaces of the cast coping keepers. The surface smoothness of the cast coping keepers was inferior to that of the laser welded coping keepers. Conclusion: Laser welded keepers and cast coping keepers can meet clinical demands for the use of magnetic attachments.

Development of titanium-posted keeper-removable magnetic attachment and its effect on magnetic resonance imaging / 实用口腔医学杂志

Objective: To develop titanium posted keeper removable magnetic attachment and to decrease its influence on magnetic resonance imaging(MRI). Methods: Pre fabricated soft magnetic alloy pin cap keeper(PSAPK), casting non precious alloycoping keeper(CNPAK), casting precious alloy coping keeper(CPACK), titanium post keeper(TPK) and titanium post(TP) were prepared and applied on the maxilla of a volunteer, MRI was taken and measured. Results: ①The attachments producing artifacts in MRI from the biggest to the smallest were listed in following rank: PSAPK, CNPAK, CPACK, TPK and TP. ②After removing the keeper from titanium post keeper, the post had no artifact on MRI. ③The artifact was the smallest taken with SE sequence. Conclusion: Titanium post keeper is an effective way to solve the artifact problem and will bring benefits to the patients who need MRI examination of head.

Stress distribution of implanted complete overdentures retained with two types magnetic attachment / 实用口腔医学杂志

Objective:To study the stress distribution of Magsoft (cushion type) and Magnedisk magnetic attachment. Methods: 2 overdentures were prepared on each of 5 edentulous jaw models. The overdentures were pared and retained with Magnedisk and Magsoft magnetic attachments respectively.Photoelastic analysis was used to study the stress distribution for the implanted complete overdentures. Results: Under the same load, around the implants, the stress under the overdentures retained with Magsoft was lower than that with Magnedisk. Compared with Magnedisk, the stress around the abutments under the overdenture retained with Magsoft were distributed in a more even manner. Conclusion: Magsoft magnetic attachment has better biomechanical characteristic than Magnedisk and can distribute stress more evenly throughout the whole supporting structure for its special cushioned design.

Fatigue test of retention force of magnetic attachment and stud-type attachment / 实用口腔医学杂志

Objective:To study retention force durability of root-type attachments.Methods:Five magnetic attachments(Magfit EX-600),semi-precise stud-type attachments(Bedent) and precise stud-type attachments(Dalbo-classic) were fixed on a thermal-cycling and mechanical-loading machine respectively.The retention force of each attachment was measured at the baseline and after every 1,000 cycles of seating-removing.Results:The average retention force of magnetic attachments was(3.85?0.107) N at the baseline which attenuated for 3.38% after 10,000 cycles;The retention force of semi-precise group was(14.10?0.144) N originally and decreased 90.06% of the original force after 10,000 cycles.The primary force of the precise group was 33.14 N and was adjusted to(11.95?0.082) N as baseline attenuating for 74.56%.Conclusion: The retention force of magnetic attachments is lower than the stud attachments but is stable for 10 years.The retention force of stud-type attachments is larger at the baseline but reduced rapidly.

The study of galvanic corrosion between soft magnetic alloy and 4 types of dental alloys in common dental application / 实用口腔医学杂志

0.05).Conclusion: Feasibility of galvanic corrosion between Fe-16Cr-2Mo soft magnetic alloy and dental alloys used in clinic application can be omitted.

A STUDY ON THE PHYSICAL PROPERTIES AND BIOLOGICAL CHARACTERISTICS OF DENTAL MAGNETIC ATTACHMENTS / 대한치과보철학회지

In order to investigate various physical and biological properties of dental magnetic attachments studies on retentive characteristics, corrosion properties, cytotoxicity of different magnetic systems for dental applications were done. For the study of retentive characteristics changes of retentive force by increasing air gap, wear properties of various attachment systems and loss of magnetic force by heat treatment were measured. For the study of corrosion property of magnet covering metal electrochemical corrosion was done in artificial saliva and 0.9% NaCl solution between -1,000 mVSCE and +1,000 mVSCE. Anodic polarization curves are obtained about 6 types of samples and 2 types of solution. Corroded surfaces were examined with metallurgical microscope, scanning electron microscope and surface profilometer. For the study of cytotoxicity of magnetic attachment and its field cell growth and agar overlay test were done. The results of this study were as follows. 1.In Magnetic attachments using closed circuit retentive force at zero air gap was greater than magnets using open circuit, but decrease of retentive force by increasing air gap was also greater than open systems. 2.After 40,000 cycles of wear test all mechanical attachment resulted in varing degree of retention loss but in magnetic attachments no loss of retentive force was observed. 3.The magnetic attachment using Neodymium magnet showed early loss of retentive force about 200degrees C but attachment using Samarium magnet showed some resistance to heat treatment and complete retention loss was observed about 500degrees C. The keeper was not influenced by heat treatment in retention. 4.In electrochemical corrosion test Dyna magnetic attachment covering metal showed the highiest corrosion resistance and Shiner magnet covering metal showed the least corrosion resistance and examination of corroded surface with metallurgical microscope, scanning electron microscope and surface profilometer also showed same results with anodic polarization curves. 5.The result of cell culture tests on the magnet covered with metal showed least recognizable cytotoxicity.