title: Masticatory muscle activity evaluation by electromyography in subjects with zygomatic implants.
abstract: BACKGROUND
  Zygomatic implants are an alternative treatment in the rehabilitation of atrophic maxilla to promote stability in the stomatognathic system. The aim of this study was to compare the electromyographic (EMG) activity of masseter and temporalis muscles in controls and in individuals with complete implant-supported dentures anchored in the zygomatic bone.
  
  
  METHODS
  Fifty-four volunteers of both genders (mean age 52.5 years) were selected and distributed into two groups: Individuals with zygomatic implant (ZIG; n=27) and fully dentate patients (CG; n=27). MyoSystem-BR1 was used to assess masseter and temporalis muscles EMG activity in different mandibular movements: protrusion, clenching, maximal voluntary contraction (MVC) with Parafilm M®, right and left laterality and chewing (peanuts and raisins). Data was processed, normalized (MVC) and analyzed using the SPSS 21.0. Student t-test (P ≤ 0.05) was used for group comparison.
  
  
  RESULTS
  The results were statistically significant (P ≤ 0.05) for protrusion, clenching, right and left laterality and raisin chewing. For the mandibular posture conditions, the ZIG obtained higher EMG activity patterns when compared to CG. For the masticatory performance during chewing of peanuts and raisins, the ZIG showed higher EMG mean values when compared to CG.
  
  
  CONCLUSIONS
  The zygomatic implant promoted an active response of the muscle fibers (hyperactivity) during both mandibular posture and chewing conditions, probably due to the absence of periodontal receptors, which play a significant role for preparing a bolus for swallowing.
authors.affiliation: Avenida do Café, s/n, School of Dentistry of Ribeirão Preto, University of São Paulo, 14040-904 Ribeirão Preto, São Paulo, Brazil, palinkas@usp.br.
authors.forename: M
authors.initials: M
authors.lastname: de Rossi
authors.forename: M
authors.initials: M
authors.lastname: Palinkas
authors.forename: B
authors.initials: B
authors.lastname: de Lima-Lucas
authors.forename: C-M
authors.initials: CM
authors.lastname: Santos
authors.forename: M
authors.initials: M
authors.lastname: Semprini
authors.forename: L-F
authors.initials: LF
authors.lastname: Oliveira
authors.forename: I
authors.initials: I
authors.lastname: Hallak-Regalo
authors.forename: E-O
authors.initials: EO
authors.lastname: Bersani
authors.forename: R
authors.initials: R
authors.lastname: Miglioranca
authors.forename: S
authors.initials: S
authors.lastname: Siéssere
authors.forename: S-C
authors.initials: SC
authors.lastname: Hallak-Regalo
mesh_terms: D000328:Adult; D000368:Aged; D019094:Dental Prosthesis, Implant-Supported; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008406:Masseter Muscle / Q000502:physiology*; D008875:Middle Aged; D013703:Temporal Muscle / Q000502:physiology*; D015050:Zygoma / Q000601:surgery*