Electromyographic analysis of masticatory and neck muscles in subjects with natural dentition, teeth-supported and implant-supported prostheses.
OBJECTIVE
To compare the electromyographic (EMG) characteristics of masticatory and neck muscles in patients with natural dentition, teeth-supported prostheses and implant-supported prostheses.


METHODS
Twenty-five subjects aged 40-80 years were examined. Five patients had maxillary and mandibular implant-supported fixed prostheses; five patients had mandibular implant-supported fixed prosthesis and maxillary removable complete denture; seven patients had implant-supported fixed prosthesis (one arch) and natural dentition or full-arch tooth-fixed prosthesis (one arch); and eight control subjects had natural dentition or single tooth-fixed prostheses. Surface EMG of masseter, temporal and sternocleidomastoid muscles was performed during maximum teeth clenching and unilateral gum chewing. Interarch dental contacts were assessed with shim stocks.


RESULTS
All groups had similar interarch dental contacts (P>0.05). During clenching, patients with maxillary and mandibular implant-supported fixed prostheses had unbalanced standardized masseter and temporalis anterior activities (74%), with significantly larger values found in the other patients and control subjects (all mean values larger than 86%, P=0.017). All patients chewed with significantly larger muscular potentials than control subjects (on average, 1434-2100 microV s vs. 980 microV s, P=0.04), and had altered muscular patterns (left side, P=0.021). The patients with one arch with natural dentition/tooth fixed prostheses had chewing muscular patterns similar to the control subjects.


CONCLUSIONS
Clenching with the analyzed prostheses was performed with a relative increment of temporalis activity. Neuromuscular coordination during chewing was larger in patients who maintained their teeth or dental roots, independently from the number of dental contacts.
Tartaglia
Gianluca M
GM
Dipartimento di Morfologia Umana, Functional Anatomy Research Cente, Facoltà di Medicina e Chirurgia, Laboratorio di Anatomia Funzionale dell'Apparato Stomatognatiotaco, Università degli Studi di Milano, Milano, Italy.
Testori
Tiziano
T
Pallavera
Andrea
A
Marelli
Bruno
B
Sforza
Chiarella
C
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002638:Chewing Gum; D003442:Crowns; D000044:Dental Abutments; D003766:Dental Occlusion; D017266:Dental Prosthesis; D019094:Dental Prosthesis, Implant-Supported; D003817:Dentition; D003779:Denture Design; D003827:Denture, Complete, Upper; D004576:Electromyography; D005260:Female; D019416:Head Movements / Q000502:physiology; D006801:Humans; D007574:Jaw Relation Record; D008297:Male; D008406:Masseter Muscle / Q000502:physiology; D008409:Mastication / Q000502:physiology; D008410:Masticatory Muscles / Q000502:physiology*; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology; D009334:Neck Muscles / Q000502:physiology*; D011187:Posture / Q000502:physiology; D013703:Temporal Muscle / Q000502:physiology
D002638:Chewing Gum