Electromyographic assessment of jaw muscles in patients with All‐on‐Four fixed implant‐supported prostheses

Abstract

This study evaluated the electromyographic (EMG) characteristics of masticatory muscles in patients with fixed implant-supported prostheses according to All-on-Four(®) principles and in control healthy dentate subjects. Twenty-six subjects aged 50-74 years were examined. Eighteen were edentulous and had been successfully rehabilitated with (i) mandibular All-on-Four(®) implant-supported fixed prostheses and maxillary complete dentures (10 patients) and (ii) mandibular and maxillary All-on-Four(®) implant-supported fixed prostheses (eight patients). Eight reference subjects had natural dentition. Surface EMG recordings of the masseter and temporalis muscles were performed during maximum voluntary teeth clenching and during unilateral gum chewing. All values were standardised as percentage of a maximum clenching on cotton rolls. During clenching, a good global neuromuscular equilibrium was found in all participants. During chewing, all groups had similar values of working-side muscle activities and of chewing frequency. No significant differences in the analysed EMG parameters were found between the patients with mandibular and maxillary All-on-Four(®) implant-supported prostheses and the reference subjects. In contrast, standardised pooled muscle activities and standardised muscular activities per cycle were larger in patients with a maxillary removable prosthesis than in control subjects (Kruskal-Wallis test, P < 0·01). Also, patients wearing a complete maxillary denture showed a poor neuromuscular coordination with altered muscular pattern and lower values of the index of masticatory symmetry than dentate control subjects (P < 0·01). EMG outcomes suggest that All-on-Four(®) implant-supported prostheses may be considered a functionally efficient treatment option for the rehabilitation of edentulous patients with reduced residual bone volume.

Medium‐ and Long‐Term Complications in Full‐Arch Rehabilitations Supported by Upright and Tilted Implants

“…However, it has been demonstrated that patients wearing implant-supported prostheses positioned following the All-on-Four protocol do not show modifications in neuromuscular equilibrium as compared with patients with natural dentition or wearing one fixed prosthesis and one removable one. 29 The same was also observed in studies evaluating other types of implant-supported rehabilitations. 30 Interestingly, the present investigation did not report any fracture of the framework or the abutments, suggesting that these types of complications, which can be solved only through complete substitution of the prosthesis, can be avoided using an adequate prosthetic protocol.…”

“…The cause of these complications should be sought in parafunctional habits. However, it has been demonstrated that patients wearing implant‐supported prostheses positioned following the All‐on‐Four protocol do not show modifications in neuromuscular equilibrium as compared with patients with natural dentition or wearing one fixed prosthesis and one removable one . The same was also observed in studies evaluating other types of implant‐supported rehabilitations …”

Electromyographic analysis of the oral phase of swallowing in subjects with and without atypical swallowing: A case‐control study

“…ssEMG is considered a helpful tool in the analysis of masticatory muscle function and its use in measuring the activity of MM, TA and SM during clenching has been widely studied. 31,32,34,37,39 In contrast, only a few studies have been performed regarding muscular behaviour during swallowing by means of ssEMG 32,35 and the recruitment of masticatory and submental muscles during this function is still unclear.…”

Preliminary approach for the surface electromyographical evaluation of the oral phase of swallowing

“…Standardised surface electromyographical protocols during clenching and chewing have been studied and accepted by the scientific literature as a useful tool to evaluate the superficial jaw closing and opening muscles (TA, MM, SM) activity, and therefore, they have entered daily clinical practice . On the contrary, the ssEMG assessment of swallowing is still an open field of research and further scientific approval is needed before clinical applications…”

“…Among jaw closing and opening muscles, the MM, the TA and the SM activities have been largely electromyographically studied in maximal voluntary clenching (MVC) and during mastication . The repeatability of standardised protocols for both tasks has been tested and clinical studies have been proposed .…”