Rehabilitation of edentulous patients with overdentures helps to improve their oral health-related quality of life. A conventional implant provides retention and stability to an overdenture, influencing the long-term success of the overall treatment and patient satisfaction. However, such treatment may require favourable anatomical and financial factors which may limit conventional implant placement in atrophic residual ridges. Investigation of the anterior alveolar bone morphology using lateral cephalometric radiographs of 154 edentulous patients who fail to tolerate conventional dentures aids in the positioning of dental implants in residual ridges. Although there may be adequate bone stock for implant placement in these cases, residual ridge configuration can limit the use of conventional implants. There are few conservative and cost-effective treatment options for these patients, one may be mini dental implant overdentures. Currently, mini dental implant overdentures are an acceptable treatment alternative to restore residual ridges. However, several dentists still perceive mini dental implants as inferior due to their small diameter and limited success data. The emergence of new mini dental implants with improved design features may enhance their performance. There is a gap in knowledge regarding the strength of mini dental implants and the effect of different designs on their resistance to mechanical failure. This thesis showed that their length did not affect their resistance to failure by overloading. However, higher resistance to failure was found with straight mini dental implants than with angled ones. The resistance to failure was also affected by the angled mini dental implant orientation towards the load. All 36 implants were tested under high loading conditions, according to International Organization for Standardization 14801:2016 test, and showed resistance to failure values between 292 N â 329 N. Such results were promising compared to data obtained from the literature regarding the maximum biting force of patients treated with previous designs of mini dental implant overdentures. Nevertheless, there is a dearth of scientific guidance in the current literature pertaining to the mini dental implants required to provide predictable retention and stability to overdentures. Therefore, a range of directional tensile and compressive forces were simulated on mini dental implant overdentures to evaluate the implant number and distribution effect upon overdenture retention and stability. The resistance to axial and para-axial dislodgement and base movements of mini dental implant overdentures improved with increasing the number of implants from 2 to 4. Careful planning of their distribution within the arch showed that widely spaced mini dental implants provided better retention and stability for the overdenture. The results suggested that the mini dental implant attachments provide acceptable retention for overdentures within their expected service of 12 months. However, the number or distribution did not affect their wear and retention loss. Consequently, annual replacement of worn-out nylon attachment inserts tested was needed to maintain the overdenture retentiveness.
Mini Dental Implants Resistance to Failure and the Effect of their Number and Distribution on the Mandibular Overdentures Retention and Stability
Alshenaiber, R. (Author). 31 Dec 2022
Student thesis: Phd