So you think implants are the sine qua non of rehabilitation do ya?

Objectives: We aimed to determine whether people with implant-supported bridges

in both jaws, thus lacking periodontal receptors, adjust jaw muscle activity to food

hardness during mastication.

Materials and Methods: Thirteen participants with implant-supported bridges in

both jaws and 13 with natural dentition chewed and swallowed soft and hard gelatinebased

model foods, while electromyographic (EMG) activity of the masseter and

temporal muscles was recorded bilaterally together with the position of the mandible.

Data were compared by using a mixed-design ANOVA model and a P-valueo0.05 was

considered statistically significant.

Results: The number of chewing cycles and the duration of the masticatory sequence

increased with food hardness in both groups, whereas vertical and lateral amplitude of

the jaw movements, and the jaw-opening velocity, increased significantly with food

hardness only for the dentate group. Although both groups adapted the EMG activity to

the hardness of the food, the implant participants showed a significantly weaker

increase in EMG activity with increased food hardness early during the masticatory

sequence than the dentate participants did. In addition, the implant group showed

significantly less reduction of muscle activity during the progression of the masticatory

sequence than the dentate group.

Conclusions: People with implant-supported bridges show an impaired adaptation of

the muscle activity to food hardness during mastication. We suggest that a lack of

sensory signals from periodontal mechanoreceptors accounts for the impairment.