The present study focused on the hypothesis that dietary supplementation with medium-chain TAG (MCT) will improve cognitive function in aged dogs by providing the brain with energy in the form of ketones. Aged Beagle dogs were subjected to a baseline battery of cognitive tests, which were used to establish cognitively equivalent control or treatment groups. The dogs in the treatment group were maintained on a diet supplemented with 5·5 % MCT. After an initial wash-in period, all the dogs were tested with a battery of cognitive test protocols, which assessed sequentially landmark discrimination learning ability, egocentric visuospatial function and attention. The groups were maintained on the diets for 8 months. The MCT-supplemented group showed significantly better performance in most of the test protocols than the control group. The group differences also varied as a function of task difficulty, with the more difficult task showing greater supplementation effects than the easier tasks. The group given the MCT supplement showed significantly elevated levels of b-hydroxybutyrate, a ketone body. These results indicate, first, that long-term supplementation with MCT can have cognition-improving effects, and second, that MCT supplementation increases circulating levels of ketones. The results support the hypothesis that brain function of aged dogs can be improved by MCT supplementation, which provides the brain with an alternative energy source.Brain ageing: Cognitive functions: Dogs: Medium-chain TAG: Ketone bodies Dog cognitive function, like that of other mammals, becomes impaired over the course of ageing, and it provides a model of human cognitive ageing (1,2) . Decline in energy metabolism is a common feature of ageing in animals, and it is one of the several processes that are closely associated with age-dependent cognitive decline. Rapoport et al. (3) found that brain glucose metabolism was reduced by up to 30 % between 3 and 12 months of age in rats. London et al. (4) reported that brain glucose metabolism was significantly reduced in Beagle dogs at 6 years of age than in 1-year-old dogs. Further changes occurred later in life, but in a manner that varied between brain structures. Brain metabolic decline has also been reported in aged monkeys (5) and human subjects (6) , and it appears to be particularly more pronounced in pathological ageing. Alexander et al.(7) reported that cerebral glucose metabolism was significantly lower in old patients with Alzheimer's disease than in healthy old control subjects. Drzezga et al.(8) traced the development of cognitive decline in patients with mild cognitive impairment, discovering that the clinical symptoms of Alzheimer's disease were associated with further declines in cerebral glucose metabolism. These data suggest that the age-associated reduction in cerebral glucose metabolism is a common feature in ageing, that the process involved may be progressive, starting around the middle age, and that metabolic decline contributes to cognitive decline associated with ...

The purpose of this study is to use cone-beam computerized tomography (CBCT) scans with oblique-transverse reconstruction modality to measure and compare the anterior loop length (AnLL) of the mental nerve between gender and age groups and to compare the difference between the right and left sides. Sixty-one female and 61 male CBCT scans were randomly selected for each age group: 21-40, 41-60, and 61-80 years. Both right- and left-side AnLLs were measured in each subject using i-CATVision software to measure AnLLs on the oblique transverse plane using multiplanar reconstruction. The anterior loop was identified in 85.2% of cases, with the mean AnLL of the 366 subjects (732 hemimandibles) being 1.46 ± 1.25 mm with no statistically significant difference between right and left sides or between different gender groups. However, the mean AnLL in the 21-40 year group (1.89 ± 1.35 mm) was larger than the AnLL in the 41-60 year group (1.35 ± 1.19 mm) and the 61-80 year group (1.13 ± 1.08 mm). In conclusion, when placing implants in close proximity to mental foramina, caution is recommended to avoid injury to the inferior alveolar nerve. No fixed distance anteriorly from the mental foramen should be considered safe. Using CBCT scans with the oblique-transverse method to accurately identify and measure the AnLL is of utmost importance in avoiding and protecting its integrity.

The objective of this ex vivo cadaver study was to determine the accuracy of cone beam computerized tomography (CBCT) and a 3-dimensional stereolithographic (STL) model in identifying and measuring the anterior loop length (ANLL) of the mental nerve. A total of 12 cadavers (24 mental nerve plexus) were used for this study. Standardized CBCT scans of each mandible were obtained both with and without radiographic contrast tracer injected into the mental nerve plexus, and STL models of the two acquired CBCT images were made. The ANLL were measured using CBCT, STL model, and anatomy. The measurements obtained from the CBCT images and STL models were then analyzed and compared with the direct anatomic measurements. A paired sample t test was used, and P values less than .05 were considered statistically significant. The mean difference between CBCT and anatomic measurement was 0.04 mm and was not statistically significant (P = .332), whereas the mean difference between STL models and anatomic measurement was 0.4 mm and was statistically significant (P = .042). There was also a statistical significant difference between CBCT and the STL model (P = .048) with the mean difference of 0.35 mm. Therefore, CBCT is an accurate and reliable method in determining and measuring the ANLL but the STL model over- or underestimated the ANLL by as much as 1.51 mm and 1.83 mm, respectively.

The objective of this ex vivo cadaver study was to determine the accuracy of cone beam computed tomography(CBCT) and 3D stereolithographic(STL) model in identifying and measuring the anterior loop length(ANLL) of the mental nerve. A total of 12 cadavers (24 mental nerve plexus) were used for this study. Standardized CBCT scans of each mandible were obtained both with and without radiographic contrast tracer injected into the mental nerve plexus. STL models of the two acquired CBCT images were made. ANLL were measured using CBCT, STL and anatomy. The measurements obtained from the CBCT images and STL models were then analyzed and compared with the direct anatomic measurements. Paired sample t-test was used. P values less than .05 was considered statistically significant. The mean difference between CBCT and anatomic measurement was 0.04mm and not statistically significant (p= .332) while the mean difference between STL and anatomic measurement was 0.4mm and statistically significant (p=.042). There was also a statistical significant difference between CBCT and STL (p=.048) with the mean difference of 0.35mm. Therefore, CBCT is an accurate and reliable method in determining and measuring the ANLL while the STL over or underestimated the ANLL by as much as 1.51mm and 1.83mm respectively.