Masticatory muscle activity evaluation by electromyography in subjects with zygomatic implants

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. 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. 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. 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

Using fixed prosthesis on Implants Branemark Protocol: the effects over the masticatory musculatures electromyographic activity

Historicamente a total perda da dentição prejudica o desempenho funcional da população. Preocupada com esta realidade a Odontologia criou métodos de reabilitação destes indivíduos desdentados. Entre eles, destacam-se as Próteses Totais Removíveis, que apesar de amplamente utilizadas, ainda não representam o ideal de reabilitação bucal. Com o aparecimento dos implantes dentais propostos por Bränemark, a associação entre próteses totais mandibulares e implantes instalados na região anterior da mandíbula tornou possível um novo conceito de tratamento do desdentado, provendo-o de aparato protético fixado aos implantes por meio de parafusos. Estudos longitudinais multicentricos validaram este conceito terapêutico, porém avaliações objetivas sobre sua influência no sistema estomatognático são necessárias. O protocolo Branemark otimiza a capacidade cinestésica dos indivíduos desdentados, anteriormente prejudicada. O método científico capaz de suportar esta constatação é a eletromiografia de superfície. Amplamente empregada em outros seguimentos da medicina, a eletromiografia foi utilizada neste estudo para avaliar um protocolo de simulações funcionais, tais como: repouso, trituração de alimentos com diferentes texturas, movimentos mandibulares, projetado para comparação entre indivíduos adultos dentados (grupo controle) e indivíduos reabilitados por Protocolo Branemark. Concluiu-se que o uso de Protocolo Branemark gerou um equilíbrio da atividade eletromiográfica dos músculos testados durante a manutenção das posições posturais e propiciou padrões de contração eletromiográfica semelhantes aos padrões desenvolvidos pelos indivíduos dentados na mastigação.Historically a total loss of teeth impairs the functional performance of the affected population. Concerned about this reality, the Dentistry has created rehabilitation methods for those toothless individuals. Among the most popular methods is the Fully Removable Prosthesis, which although widely used, does not represent the ideal of a buccal rehabilitation. Subsequently to the dental implants proposed by Bränemark, the association between the fully mandibular prosthesis and mandibular anterior area implants, enabled a new concept of treatment for the toothless, providing them with a prosthetic apparatus attached to implanted fixations. Longitudinal multicentered studies validated this therapeutical concept, but objective evaluations are made necessary, especially on their influence on the stomatognatic system. The Branemark protocol optimizes the previously harmed kinesthetic capacity of the toothless. The scientific method that can support this is the electromyography of the surface. Largely used in other segments of medicine, the electromyography has been used in this study to evaluate a protocol of functional simulations, such as: relaxation, triturating of foods with different textures, jaw movements, to compare adults with natural teeth (controlled group) and individuals rehabilitated by the Branemark Protocol. In conclusion, the use of Branemark Protocol generated equilibrium of the electromyography activity of the tested muscles during the postural positions and propitiated electromyographyc contraction standards similar to the standards developed by normally toothed individuals during chewing

Fracture Resistance of the Implant-Abutment Connection in Implants with Internal Hex and Internal Conical Connections Under Oblique Compressive Loading: An In Vitro Study

The objective of this study was to verify if differences in the design of internal hex (IH) and internal conical (IC) connection implant systems influence fracture resistance under oblique compressive forces. Twenty implant-abutment assemblies were utilized: 10 with IH connections and 10 with IC connections. Maximum deformation force for IC implants (90.58 +/- 6.72 kgf) was statistically higher than that for IH implants (83.73 +/- 4.94 kgf) (P = .0182). Fracture force for the IH implants was 79.86 +/- 4.77 kgf. None of the IC implants fractured. The friction-locking mechanics and the solid design of the IC abutments provided greater resistance to deformation and fracture under oblique compressive loading when compared to the IH abutments. Int J Prosthodont 2009;22:283-286