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.
Comparative Study of Implant Supported Overdenture Retained with Two Types of Attachments
Objectives: This study was conducted to compare implant retained mandibular overdenture with two different attachments (ball and socket and locator). Subject and methods:7 edentulous patients were selected according to certain criteria. Each patient received two platform switched implants placed in the mandibular canine-premolar region bilaterally. GROUP I: Locator attachments were used to retain the implant-supported overdentures. Locator abutments were loaded after 2-3 months. All patients received conventional maxillary dentures. After follow up periods we removed the attachment with wash period 1month then we used ball and socket attachment GROUP II. The two groups were evaluated for retention, masticatory efficiency and EMG at 0, 3 and 6 months after loading of each attachment. Results: regarding the effect of time on retention of both groups in ball group there was a significant increase in retention at base line till 3 months and decrease from 3-6 months, while locator group there was increase of retention through all periods. Regarding the effect of time on both groups the masticatory efficiency of both ball and locator group have no significant difference through all periods. Comparing the two groups the masticatory efficiency has no significant difference except on chewing carrots the numbers of strokes till first swallow increase in ball group, and on chewing peanut after 6 months the ball group show higher time till first swallow than locator as well as the time to empty mouth. Regarding the effect of time on both groups the electromyographic activity of both masseter and temporalis muscles has no significant difference through all periods except in locator group decrease the activity of masseter after 3 months. Conclusions: the ball attachment at the beginning has a higher retention quality than locator attachment, by time ball attachment loss some of its retention rather than locator attachment. The electromyographic activities and the masticatory efficiency of temporalis and masseter muscles of both ball attachment and locator attachment were comparable. Codex : 06/1801 azhardentj@azhar.edu.eg http://adjg.journals.ekb.eg
The telescoped complete denture: a research report at the clinical level.
Abstract 1. The retention of a few natural teeth over which a complete denture may be telescoped provides better retention and stabilization than is possible with the usual complete dentures. 2. The reduction of the length of the crowns of the teeth being retained provides a more favorable crown-root proportion and frequently results in the elimination of periodontal disease. 3. Where lower natural anterior teeth exist, the retention of even two or three upper incisors provides the bony support in the anterior part of the upper ridge with protection against traumatic vertical and horizontal pressures from the lower teeth. Ridge resorption has become a national tragedy; any method of preventing it should be welcomed. 4. The retention of two or more lower natural teeth over which a full mandibular denture is telescoped provides a means of better retention and stabilization than is otherwise possible. 5. The psychologic impact of having all the teeth removed may be ameliorated and the patients may be conditioned to expect the eventual need for complete dentures. 6. Regardless of the theories stating that stabilization is all that is essential, both stabilization and retention are achieved in telescoped complete dentures. 7. The telescoped complete denture acts as a removable splinting device for the abutment teeth. 8. When individual teeth are joined together by a gold bar they provide greater stabilization and retention than if they were not splinted together, e.g., as with two lower cuspids. 9. With only a few lower teeth remaining to support a lower prosthesis, it is wise to consider the removal of the upper natural teeth in order to increase the longevity of the lower teeth. 10. While we advocate the use of metal secondary crowns in telescopes in fixed and removable partial dentures, acrylic resin seems more practical for use in telescoped full dentures. The exception occurs where there is no labial flange. In this situation gold telescoped veneer crowns are used. However, we consider these as removable partial dentures rather than telescoped complete dentures.