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

Abstract

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 μ) 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.

Functional Neuroplasticity of Adults with Partial or Complete Denture Rehabilitation with or without Implants: Evidence from fMRI Studies

“…The majority of the studies conducted within-group comparisons, with the same group of patients receiving different denture treatments at different time points (longitudinal). Two studies were cross-sectional with between-group comparisons [ 27 , 28 ]. Meanwhile, only three studies collected brain activity data from their patients before the experimental interventions: Two collected data while patients were wearing their old complete dentures [ 23 , 29 ], and one collected data while patients were completely edentulous, without dentures [ 24 ].…”

“…For Yan et al [ 27 ], concerns were raised regarding confounding variables, as they had compared patients who already had undergone different types of denture rehabilitations, without disclosing or accounting for the differences in the socioeconomic status between the patient groups. Significant risks were identified in the incomplete outcome data for three studies [ 24 , 28 , 32 ], as they had analyzed the fMRI data based on their subjective judgments (i.e., “no signal”, “mild signal”, versus “strong signal”) instead of the routine statistical tests based on numerical values. Due to the heterogeneity of the studies and the lack of brain coordinates reported by the studies, a neuroimaging meta-analysis was not feasible.…”

“…Circumstantial evidence from jaw-clenching studies regarding complete edentulous individuals rehabilitated with complete dentures, implant-supported overdentures, or implant-supported fixed dentures ( n = 2) [ 27 , 28 ] suggested that the implant-supported fixed dentures could be the best option, as compared to implant-supported overdentures and complete dentures, as it was associated with higher brain activity levels in various brain regions, including those corresponding to the primary sensory (PostCG) and motor cortices (PreCG). Gum-chewing studies ( n = 4, one with partial edentulous participants) [ 23 , 24 , 25 , 31 ] found that the brain activity levels in various brain regions, such as the prefrontal cortex, PreCG, and the parietal cortex, could be improved by having a dental arch fully replaced, instead of partially replaced, or having a new complete denture replacement.…”

“…The following two studies reported inter-group differences. First, Bhattacharjee et al [ 28 ] recruited 18 edentulous patients (10 males and 8 females, mean age ± SD: 60.7 ± 4.0 years, fully edentulous period not reported) and allocated them to 3 treatment groups: (1) complete dentures; (2) maxillary complete denture and mandibular implant-supported overdenture; and (3) implant-supported fixed dentures. FMRI scans were performed four weeks after treatment completion.…”

“…Even if this recommendation were neglected, the data reported in the nine original studies reviewed here would not constitute a neuroimaging meta-analysis, which generally requires brain coordinates of activated regions to be reported based on whole-brain analysis. Unfortunately, most of the studies only reported the names of the activated brain regions, without the coordinates, such as [ 24 , 27 , 28 , 29 , 31 , 32 ]. Consequently, the brain coordinates could only be identified in three studies: complete denture > implant-supported overdenture during chewing [ 30 ]; lower removable partial dentures with full dental arch > shortened dental arch during chewing [ 25 ]; and new complete dentures > old complete dentures during chewing [ 23 ].…”