A comparative evaluation of neurophysiological activity, active tactile sensibility and stereognostic ability of complete denture prosthesis, and implant-supported prosthesis wearer-A pilot study

Aim The study aimed to evaluate the effect of implant-supported prosthesis in completely edentulous participants in terms of osseoperception ability, neural activity, and stereognostic ability in comparison to removable prosthetic options. Materials and Methods A total sample of 18 patients, irrespective of gender and age were allocated into three groups according to the three-treatment protocol (upper and lower complete denture, upper complete denture opposing lower implant-retained overdenture, implant-supported fixed prosthesis in both arches). Four weeks after completion of the treatment procedure active tactile sensibility (ATS) was checked by using varying thicknesses (12, 40, 80, 100, 200 mu) of articulating foils and papers. Functional magnetic resonance imaging (fMRI) was performed to record neurophysiological activity in cerebral cortex in all the participants. Various forms of test pieces (heat cure acrylic resin) were used to evaluate stereognostic ability. Data regarding the neurophysiological activity were analyzed by using Krushkal-Wallis test and p <= 0.05 was considered to be statistically significant. Data from stereognostic ability test procedure and ATS were compared by using chi-squared test and p <= 0.05 was considered to be statistically significant. Results Statistically significant difference was found in between the articulating foils in terms of true negative responses as the foil thickness increased in participants wearing complete denture in both the arches (p = 0.004) and implant-supported fixed prosthesis in both the arches (p = 0.010). Participants in implant-supported fixed prosthesis group showed significantly more activation in primary motor cortex (right side), somatosensory cortex (left side), angular gyrus (both sides), temporal lobe (left) compared to other groups. No significant difference found in thalamus and premotor cortex region in between the participants of different groups. No statistically significant difference found in between the groups in terms of true responses identifying correct shapes. Mean number of correct responses in stereognostic ability test were 4.16 (83.33%), 3.5 (70%), 3.83 (76.66%) for participants of complete denture group, upper complete denture opposing lower implant retained overdenture group, and implant-supported fixed prosthesis group, respectively. Conclusion Primary motor cortex, somatosensory cortex, and other regions of brain were diffusely activated in participants wearing implant-supported fixed prosthesis in both the arches. Less number of false responses were recorded in participants of implant-supported fixed prosthesis group and upper complete denture opposing lower implant-retained overdenture group in ATS test compared to participants wearing complete denture in both the arches.