Oral health and risk of cognitive disorders in older adults: A biannual longitudinal follow-up cohort.

BACKGROUND: Oral health may be associated with cognitive disorders such as mild cognitive impairment or dementia. OBJECTIVE: This study elucidates the effects of oral health conditions on the progression of cognitive disorders. METHODS: Data were collected from 153 participants of the Korean Longitudinal Study on Cognitive Aging and Dementia cohort who completed the longitudinal dental examinations and cognitive function assessments using the three-wave biannual survey. We analysed the relationship between dental factors and the conversion of cognitive function. RESULTS: The ratio of maxillary removable partial denture use (p = .03) was high in the converter and mild cognitive impairment/dementia groups. The low-grade ratio of posterior masticatory performance increased in the converter and mild cognitive impairment/dementia groups (modified Eichner index 2, p = .04). The mild cognitive impairment/dementia group had a higher rate of complete mandibular denture use (p < .001). The converter and mild cognitive impairment/dementia groups had fewer remaining teeth (p < .05) or removable prostheses (p < .01) than the normal group. CONCLUSIONS: Masticatory performance is associated with the conversion of cognitive disorders. Our findings suggest that oral health management can help delay the progression of cognitive disorders.

McGrath Video Laryngoscopy Facilitates Routine Nasotracheal Intubation in Patients Undergoing Oral and Maxillofacial Surgery: A Comparison With Macintosh Laryngoscopy.

PURPOSE: The McGrath video laryngoscope (VL) offers excellent laryngoscopic views and increases the success rate of orotracheal intubation in patients with normal and difficult airways. The purpose of this randomized controlled trial was to compare the McGrath VL with the Macintosh laryngoscope to investigate the efficacy of the McGrath VL for routine nasotracheal intubation in patients with an expected normal airway. MATERIALS AND METHODS: To address the research purpose, the efficacy of the McGrath VL for routine nasotracheal intubation was compared with that of the Macintosh laryngoscope. The predictor variable was the laryngoscopic technique (McGrath VL vs Macintosh laryngoscope). The outcome variables were the time to successful intubation, laryngoscopic views before and after optimal external laryngeal manipulation (OELM), use of Magill forceps, ease of intubation, and severity of oropharyngeal bleeding. RESULTS: Data from 35 patients undergoing oral and maxillofacial surgery were assessed. The time to intubation was 10.5 seconds shorter in the McGrath group than in the Macintosh group (34.4 ± 13.7 vs 44.9 ± 15.6 seconds; P = .004). The incidence of grade 1 glottic view before OELM was higher in the McGrath group than in the Macintosh group (83 vs 57%; P = .019). The frequency of Magill forceps use was lower in the McGrath group than in the Macintosh group (6 vs 34%; P = .003). CONCLUSION: McGrath VL facilitates routine nasotracheal intubation in expected normal airways by providing a shorter intubation time and better laryngoscopic views compared with the Macintosh laryngoscope.

Novel FAM20A mutations in hypoplastic amelogenesis imperfecta.

Amelogenesis imperfecta (AI) is a genetically and clinically heterogeneous group of inherited dental enamel defects without any other nonoral symptoms. Recently, a disease-causing nonsense mutation (c.406C>T) in a novel gene, FAM20A, was identified in a large consanguineous family affected by AI with gingival hyperplasia. We performed mutational analyses on nine AI families with similar phenotypes and identified three homozygous mutations (c.34_35delCT, c.813-2A>G, c.1175_1179delGGCTC) in three families and a compound heterozygous mutation (c.[590-2A>G] + [c.826C>T]) in one family. An in vitro splicing assay with a minigene confirmed the mutations located in the splicing acceptor site caused the deletion of exons 3 and 6, respectively. Taking into consideration the locations of the nonsense and frameshift mutations, the mutant transcripts are most likely degraded by nonsense-mediated mRNA degradation and it results in a loss of the FAM20A protein. This study confirms the importance of the FAM20A protein in enamel biomineralization as well as tooth eruption.

A novel mutation in the AMELX gene and multiple crown resorptions.

Amelogenesis imperfecta (AI) is a heterogeneous group of genetic disorders with regard to genetic aetiology and clinical phenotype and affects tooth enamel with no other non-oral syndromic conditions. X-linked AI is caused by mutations in the amelogenin (AMELX) gene, the only AI candidate gene located on the X chromosome. To date, 15 mutations in the AMELX gene have been found to cause AI. We identified a proband with generalized hypoplastic enamel and unusual multiple crown resorption in premolars and molars. Pedigree analysis suggested an X-linked hereditary pattern. We performed mutational analysis for the AMELX gene based on the candidate gene approach. Sequencing analysis revealed a novel mutation in exon 6 (g.4090delC, c.517delC, p.Pro173LeufsX16). This frameshift mutation produces a premature stop codon within exon 6 and is predicted to replace 33 amino acids at the C-terminus with 15 novel amino acids if the mutant mRNA escapes the nonsense-mediated decay system. Although crown resorptions occur frequently in patients with the hypoplastic type of A1, an association with the AMELX mutation has not been previously reported. We believe that these findings will broaden our understanding of the clinical phenotype and pathogenesis of X-linked AI.

Design of an Yb-169 source optimized for gold nanoparticle-aided radiation therapy.

PURPOSE: To find an optimum design of a new high-dose rate ytterbium (Yb)-169 brachytherapy source that would maximize the dose enhancement during gold nanoparticle-aided radiation therapy (GNRT), while meeting practical constraints for manufacturing a clinically relevant brachytherapy source. METHODS: Four different Yb-169 source designs were considered in this investigation. The first three source models had a single encapsulation made of one of the following materials: aluminum, titanium, and stainless steel. The last source model adopted a dual encapsulation design with an inner aluminum capsule surrounding the Yb-core and an outer titanium capsule. Monte Carlo (MC) simulations using the Monte Carlo N-Particle code version 5 (MCNP5) were conducted initially to investigate the spectral changes caused by these four source designs and the associated variations in macroscopic dose enhancement across the tumor loaded with gold nanoparticles (GNPs) at 0.7% by weight. Subsequent MC simulations were performed using the EGSnrc and norec codes to determine the secondary electron spectra and microscopic dose enhancement as a result of irradiating the GNP-loaded tumor with the mcnp-calculated source spectra. RESULTS: Effects of the source filter design were apparent in the current MC results. The intensity-weighted average energy of the Yb-169 source varied from 108.9 to 122.9 keV, as the source encapsulation material changed from aluminum to stainless steel. Accordingly, the macroscopic dose enhancement calculated at 1 cm away from the source changed from 51.0% to 45.3%. The sources encapsulated by titanium and aluminum/titanium combination showed similar levels of dose enhancement, 49.3% at 1 cm, and average energies of 113.0 and 112.3 keV, respectively. While the secondary electron spectra due to the investigated source designs appeared to look similar in general, some differences were noted especially in the low energy region (<50 keV) of the spectra suggesting the dependence of the photoelectron yield on the atomic number of source filter material, consistent with the macroscopic dose enhancement results. A similar trend was also shown in the so-called microscopic dose enhancement factor, for example, resulting in the maximum values of 138 and 119 for the titanium- and the stainless steel-encapsulated Yb-169 sources, respectively. CONCLUSIONS: The current results consistently show that the dose enhancement achievable from the Yb-169 source is closely related with the atomic number (Z) of source encapsulation material. While the observed range of improvement in the dose enhancement may be considered moderate after factoring all uncertainties in the MC results, the current study provides a reasonable support for the encapsulation of the Yb-core with lower-Z materials than stainless steel, for GNRT applications. Overall, the titanium capsule design can be favored over the aluminum or dual aluminum/titanium capsule designs, due to its superior structural integrity and improved safety during manufacturing and clinical use.

X-ray fluorescence computed tomography (XFCT) imaging of gold nanoparticle-loaded objects using 110 kVp x-rays.

A conventional x-ray fluorescence computed tomography (XFCT) technique requires monochromatic synchrotron x-rays to simultaneously determine the spatial distribution and concentration of various elements such as metals in a sample. However, the synchrotron-based XFCT technique appears to be unsuitable for in vivo imaging under a typical laboratory setting. In this study we demonstrated, for the first time to our knowledge, the possibility of performing XFCT imaging of a small animal-sized object containing gold nanoparticles (GNPs) at relatively low concentrations using polychromatic diagnostic energy range x-rays. Specifically, we created a phantom made of polymethyl methacrylate plastic containing two cylindrical columns filled with saline solution at 1 and 2 wt% GNPs, respectively, mimicking tumors/organs within a small animal. XFCT scanning of the phantom was then performed using microfocus 110 kVp x-ray beam and cadmium telluride (CdTe) x-ray detector under a pencil beam geometry after proper filtering of the x-ray beam and collimation of the detector. The reconstructed images clearly identified the locations of the two GNP-filled columns with different contrast levels directly proportional to gold concentration levels. On the other hand, the current pencil-beam implementation of XFCT is not yet practical for routine in vivo imaging tasks with GNPs, especially in terms of scanning time. Nevertheless, with the use of multiple detectors and a limited number of projections, it may still be used to image some objects smaller than the current phantom size. The current investigation suggests several modification strategies of the current XFCT setup, such as the adoption of the quasi-monochromatic cone/fan x-ray beam and XFCT-specific spatial filters or pinhole detector collimators, in order to establish the ultimate feasibility of a bench-top XFCT system for GNP-based preclinical molecular imaging applications.