Purpose to examine the electromyographic (EMG) activity of the masseter muscles in patients with conventional dentures and compare it to EMG activity of fixed prosthesis, and milled bar overdentures used to rehabilitate mandibular atrophied ridges according to the All‐on‐4 concept. Methods Eighteen edentulous subjects with atrophied mandibles received complete dentures (CD, control). After 3 months, four implants were installed between the mental foramina according to the “All‐on‐4” protocol and loaded immediately. After osseointegration, fixed prostheses (FPD) or milled bar overdentures (MBO) were given to the patients in random order. Primary (amplitude), and secondary (chewing rate, time of the masticatory cycle, time of masticatory burst, and masticatory time) outcomes were evaluated 3 months after using CD, FPD, and MBO. The evaluations were made during mastication of carrot (hard) and cake (soft) foods. Results FPD and MBO were associated with a significantly higher (amplitude, time of masticatory cycle, and time of masticatory burst), and significantly lower (chewing rate and masticatory time) compared with conventional dentures. Primary and secondary outcomes did not differ between FPD and MBO. Carrot had significantly higher amplitude, chewing rate, time of masticatory burst, and masticatory time than cake, while cake had a significantly higher time of masticatory cycle than carrot. Conclusions Within limitations of this study, milled bar overdentures for All‐on‐4 implant rehabilitation of atrophied mandible is not less efficient than fixed prostheses in terms of electromyographic activity of the masseter muscle. Both prostheses significantly improve muscle activity, chewing rate, time of masticatory cycle, time of masticatory burst, and masticatory time compared with conventional dentures.

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Objectives: This study aimed to investigate both the clinical and radiographic outcomes of metal and Poly ether-ether ketone (PEEK) framework reinforcement materials for maxillary palateless ball retained implant overdentures after one year follow-up period. Materials and methods: Eight edentulous patients with edentulous maxillary ridges and implant retained mandibular overdentures who complained from lack of retention of their maxillary dentures were classified into 2 groups; group 1 included 4 patients who received palateless maxillary overdentures with cobalt chromium metal reinforcement, group 2 (included 4 patients who received palateless maxillary overdentures with PEEK reinforcement. All patients received 4 implants in canine and second premolar areas of maxilla. After 6 months, overdentures were attached to the fixtures with O/ring attachments. Clinical outcomes included Plaque indices, bleeding indices, depth of probing and implant mobility) and radiographical evaluation included marginal bone resorption. All outcomes were evaluated at prosthesis delivery, 6 months and one year after prosthesis delivery. Results: The survival rate of the implants showed significant difference, as it was 83% and 100% for metal and PEEK groups respectively. Plaque and bleeding scores, as well as pocket depth increased significantly from base line to 12 months. Bone resorption progressed significantly from 6 months to 12 months in both groups. PEEK group showed significantly lower plaque scores, bleeding scores, probing depth and bone resorption than metal one. No significant differences in mobility of the implants in-between observation times or groups were noted. Conclusion: Within the scope of this study, PEEK reinforcement for maxillary palateless implant overdentures is recommended more than metal cobalt chromium reinforcements as it showed favourable clinic and radiographical responses after one year of overdenture insertion.

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