AIM:This study aimed to compare the stresses generated by using two or four root form dental implants supporting mandibular overdentures that were retained with ball and locator attachments.METHODS:Under ANSYS environment, four 3D finite element models were prepared. These models simulated complete overdentures supported by two or four implants with either ball or locator attachments as a connection mechanism. The models’ components were created by CAD/CAM package then were imported to ANSYS. Load of 100 N was applied at the right premolar/molar region vertically and at an oblique angle of 110° from lingual direction.RESULTS:Within the conditions of this research, in all cases, it was found that cortical and cancellous bone regions were the least to be stressed. Also, the ball attachment produced higher stresses.CONCLUSION:Caps deformation and stresses are negligible in cases of using locator attachment in comparison to ball attachments. This may indicate longer lifetime and less repair/maintenance operations in implant overdentures retained by locator attachments. Although the study revealed that bone was insensitive to a number of implants or attachment type, it may be recommended to use two implants in the canine region than using four, where the locator attachments were found to be better.

AIM: The aim of the study was to assess the difference between patient satisfaction and bone height changes of mini-implant supported overdentures in comparison with conventional implant after bone expansion technique. METHODS: This randomized clinical trial contains 36 edentulous participants with thin mandibular ridges randomly divided to receive 2 mini-implants, or 2 conventional implants after ridge splitting, both treatments were done in the inter-forminal area of the anterior mandible. Then, the patients received mandibular overdentures with ball and socket attachments. At base line, after 6 and 12 months of loading the implants, patients’ satisfaction was evaluated using visual analog scale, in addition to bone height changes using Soredex DIGORA Optime Classic software. RESULTS: There was statistically significant difference in the overall satisfaction between the mini-implants and the conventional implants group; the amount of bone height changes in the mini-implant group was statistically significant less than the conventional implant group at base line, 6 and 12 months. CONCLUSION: Treatment with two mini-implants provides high level of satisfaction and less bone height changes in a follow-up period of 12 months in comparison to conventional implants after ridge expansion.

Background: Implant-retained restorations offer numerous advantages over regular removable dentures. Basically, efficient retention and stability is easily achieved by constructing a fixed restoration or at least by using overdenture attachments instead of depending on the weak physical means used with regular dentures.Methods: A geometrical model demonstrating screw retained acrylic fixed restoration, mucosa, implants, abutment, screw, alveolar bones were generated to accomplish the assessments. The parameters presented in the computer model were cantilever extent and stresses with 50 and 100 N performed to mimic the occlusal stresses. geometrics with the peripheries of stress were gained and the extreme stress at each site was designed in diagrams for analysis.Results: Stresses clustered at the elements closest to the loading point. implant deformation shows a reduction with the increase of cantilever length. Conclusion:Alveolar bone received less stresses and deformation under more rigid restoration that it distributes the applied load in a good manner than lower rigidity one.

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Aim: This study aimed to evaluate the insertion torque and initial stability of single thread implants versus double and triple thread implants.Methods: Forty-two osteotomies were prepared in fresh bovine bone. The implants used in this study were 3 types according to the thread lead design: single thread implant, double and triple thread implants (n=14). Implants were inserted in bone blocks until reaching insertion torques (30 Ncm, 40Ncm and 50Ncm) then calibration of the part of implant inserted within bone was conducted. Osstell ISQ device was used for resonance frequency analysis to assess the primary stability. The removal torque of each implant is measured at torque 50N/cm. intergroup and intragroup comparisons were performed. The p value was set to p ≤ 0.05 for all tests.Results: Regarding, implant insertion torque the highest value was found in single thread group followed by double thread group, while the lowest value was found in triple thread group. Primary stability results and removal torque revealed that, the highest value was found in triple thread group, followed by double thread group, while the lowest value was found in single thread group and a significant difference was found between different groups (p<0.001) in all measured outcomes. Conclusions: When primary stability is a concern, as in low bone quality, double and triple threaded implants can provide greater primary stability and insertion torque. Double threaded implants combine optimum insertion speed and high primary stability and insertion torque in compromised situations.