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.
biological and mechanical effect of different types of attachments on supporting structures in implant retained mandibular overdenture a Randomized clinical study
Objective: To compare between implant retained overdenture with two different attachments by measuring : Retention. Bone changes by radiographic evaluation. Subjects and Methods: Eight completely edentulous patients were selected from the Outpatient Clinic of the Prosthodontic Department; Faculty of Dental medicine, Al Azhar University and classified into two equal groups. Each patient in two groups received two implants placed in the mandibular canine-premolar region bilaterally. Group (1): four patients received two implants using equator attachments. Group (2): four patients received two implants with using magnet attachments. and the study was randomized controlled trial with Calculated samples. type of randomization in that study was Block randomization and The out comes was assessor blinded as the investigators didn’t know the type of the attachment before measuring retention or amount bone resorption Results: Results revealed that, there was no statistically significant difference in bone loss between equator and magnet during the follow up period, and there were no statistically significant mean retention values in the two groups at base line and after 3 months. But 6 months; Magnet attachment showed statistically significantly lower mean retention values than Equator attachment. By time there was a statistically significant decrease in mean retention values of magnet rather than locator attachment. Conclusion: The use of equator and magnet attachments with two implant supported mandibular overdentures leads the same effect on crestal bone resorption. At the beginning the two attachment have the same retention quality by time magnet attachment loss some of its retention rather than locator attachment
A 2-year longitudinal study of overdenture patients. Part I: incidence and control of caries on overdenture abutments.
1. The development of caries on overdenture abutments is a significant problem. In the patients examined, a high incidence of caries was noted at each recall. While few teeth were lost due to caries (none by first recall, none by second recall, and four by third recall), many teeth can eventually deteriorate and be lost (Fig. 7). 2. Caries can develop in a short period of time as shown by the results of the initial examination (caries present 2 to 8 months after insertion of the overdenture). 3. Some patients seem to be caries susceptible, as shown by the recurrence of caries, notwithstanding caries removal from the overdenture teeth at each recall. For example, a large percentage of patients with caries at the 1-year recall also had caries at the 2-year recall. 4. Patients who were placed on fluoride solution and/or had teeth treated with silver nitrate had a significant decrease in caries when compared to those who received no treatment or were placed on a placebo. 5. Fluoride caused some irritation or burning sensation in tissues of several patients. This was relieved in several patients by a decrease in the frequency of application from daily to 2 to 3 times a week.