Fig 1.
Dental state of 12 partially edentulous subjects.
Shown is the dental state of each of the present 12 partially edentulous subjects (A to L). Using Eichner’s tooth loss classification, subjects A-F were classified as B2, G-I were classified as B3, and J-L were classified as B4. The mean numbers of residual, lost, and prosthetic teeth in those groups were 18.8±3.16, 9.2±3.16, and 8.8±3.3, respectively. Residual teeth are indicated in black and prosthetic teeth in red.
Table 1.
Numbers of residual, lost, and prosthetic teeth in 12 elderly edentulous subjects.
Fig 2.
Anatomical identification of near-infrared spectroscopy channels.
The coordinates for all probe and anatomical landmark positions (Nz, Iz, A1, A2, Cz) were obtained using a 3-dimensional digitizer. Probabilistic registration was used to transcribe the measuring points for each subject according to the protocol of the Montreal Neurological Institute and those points were projected onto the cortical surface. Anatomical localization was identified using the Platform for Optical Topography Analysis Tools, with reference to the Automated Anatomical Labeling system. Orange, red, yellow, green, blue, and purple represent DLPFC (BA9), DLPFC (BA46), FPA (BA10), BA (BA45), OFC (BA11), and IPG (BA47), respectively. Each circle corresponds to a channel and the pie chart within each circle shows the percentages of areas in that channel.
Table 2.
Masticatory scores for Tooth Loss, Wearing Denture, and Young.
Table 3.
Occlusal force (N) for Tooth Loss, Wearing Denture, and Young.
Table 4.
Masticatory muscle EMG activities for Tooth Loss, Wearing Denture, and Young.
Fig 3.
Cross-sectional statistical topography under Wearing Denture and Tooth Loss conditions, as compared to Rest session.
(A) The values for [oxy-Hb] under the Tooth Loss were significantly increased (paired t-test, p<0.05), as compared to those in the Rest session, during the chewing period for BA (BA45), and the post-chewing period for DLPFC (BA46), FPA (BA10), BA (BA45), and OFC (BA11). Green square indicates chewing period. Paired t-test results showed a 5% risk rate value of 2.20 and 1% risk rate value of 3.11. (B) The values for [oxy-Hb] under the Wearing Denture were significantly increased (paired t-test, p<0.05), as compared to those in the Rest session, during the pre-chewing period for DLPFC (BA9, BA46) and FPA (BA10), during the chewing period for DLPFC (BA9, BA46), FPA (BA10), BA (BA45), OFC (BA11), and IPG (BA47), and during the post-chewing period for DLPFC (BA9, BA46), FPA (BA10), BA (BA45), OFC (BA11), and IPG (BA47). Green square indicates chewing period. Paired t-test results showed a 5% risk rate value of 2.20 and 1% risk rate value of 3.11.
Table 5.
Significantly different channels and corresponding brain regions presented in cross-sectional statistical topography of [oxy-Hb].
Fig 4.
Temporal changes under Tooth Loss and Wearing Denture conditions.
The values for [oxy-Hb] during the pre-chewing period for Wearing Denture were significantly (two-way repeated measures ANOVA and Bonferroni t-test, p<0.05) increased for DLPFC (BA46), and FPA (BA10), and during the chewing period for DLPFC (BA9, BA46), FPA (BA10), BA (BA45), and OFC (BA11), and remained increased during the post-chewing period for DLPFC (BA9, BA46), FPA (BA10), BA (BA45), and OFC (BA11) as compared to Tooth Loss. Significant differences between the conditions are indicated by a blue bar.
Table 6.
Significantly different channels and corresponding brain regions presented in temporal changes of [oxy-Hb].
Fig 5.
Cross-sectional statistical topography in Young as compared to Rest session.
The values for [oxy-Hb] in the Young were significantly (paired t-test, p<0.05) increased, as compared to those in the Rest session, during the pre-chewing period for DLPFC (BA9, BA46), FPA (BA10), BA (BA45), and OFC (BA11), during the chewing period for DLPFC (BA9, BA46), FPA (BA10), BA (BA45), OFC (BA11), and IPG (BA47), and during the post-chewing period for DLPFC (BA9, BA46), FPA (BA10), BA (BA45), OFC (BA11), and IPG (BA47). Green square indicates chewing period. Paired t-test results showed a 5% risk rate value of 2.20 and 1% risk rate value of 3.11.
Fig 6.
Temporal changes in [oxy-Hb] under Tooth Loss condition as compared to Young.
The values for [oxy-Hb] and under the Tooth Loss were significantly (two-way repeated measures ANOVA and Bonferroni t-test, p<0.05) decreased as compared to those in the Young group during the pre-chewing period for FPA (BA10) and OFC (BA11), during the chewing period for DLPFC (BA9, BA46), FPA (BA10), BA (BA45), and OFC (BA11), and during the post-chewing period for DLPFC (BA9, BA46), FPA (BA10), and BA (BA45). Significant differences between Tooth Loss and Young are indicated by a grey bar. All channels shown here correspond to channels that showed significant differences between the Wearing Denture and Tooth Loss presented in Fig 4.
Fig 7.
Temporal changes in [oxy-Hb] under Wearing Denture condition as compared to Young.
The values for [oxy-Hb] under the Wearing were significantly (two-way repeated measures ANOVA and Bonferroni t-test, p<0.05) decreased as compared to the Young during the chewing period for DLPFC (BA9, BA46), FPA (BA10), and BA (BA45), and during the post-chewing period for DLPFC (BA46) and FPA (BA10). Significant differences between Wearing Denture and Young are indicated by a blue bar. All channels shown here correspond to channels that showed significant differences between the Wearing Denture and Tooth Loss presented in Fig 4.