Hyperglycemia simultaneously induces initial caries development and enhances spontaneous occlusal surface wear in molar teeth related to parotid gland disorder in alloxan-induced diabetic rats

3D X-ray microscope acts as an accurate and effective equipment of pathological diagnosis in craniofacial imaging

Craniofacial structure and dental hard tissue used to be researched on by traditional imaging tools such as light microscope, electron microscope and micro-CT. Due to the limitations of imaging principle, resolution and 3D rendering reconstruction technique, traditional imaging tools are constrained for presenting fine structure and precise measurements. Here a brand-new imaging equipment-3D X-ray microscope is introduced to realize a more efficient scanning by demonstrating the comparison of the craniofacial structures and dental hard tissue of diabetes and normal DBA mouse. To explore a higher resolution, more efficient imaging measurement and 3D reconstruction method on craniofacial structure and dental hard tissue. The study included 12 DBA mice which were divided into two groups (control group and diabetes group). The heads were separated and scanned by 3D X-ray microscope, after which regions of interest were selected, followed by measurement and 3D reconstruction based on microscope attached software Dragonfly pro©. Hemi-mandibles were collected for enamel mineral density assessment supported by QRM-MicroCT-HA phantom. Data was submitted to paired t-tests at a 95% confidence level. The automatic assessed enamel thickness of diabetes mice decreased on average, whereas the rest of manual measurements and automatic assessed density showed no statistical difference. We constructed HA phantom assisted enamel density procedure in Dragonfly software. Craniofacial structure and dental hard tissue were well-presented both in 2D slide and 3D reconstruction viewport by 3D X-ray microscope which can be routinely used as craniofacial structure and dental hard tissue imaging tool.

[Research Progress of Cellular Lipid Droplets in Oral Diseases]

Lipid droplets are dynamic multifunctional organelles composed of a neutral lipid core and a phospholipid monolayer membrane modified by a specific set of proteins. PAT family proteins are the most characteristic lipid droplet proteins, playing an important role in regulating lipid droplet structure, function, and metabolism. The biogenesis of lipid droplets involves neutral lipid synthesis and the nucleation, budding, and growth of the lipid droplets. Lipid droplets not only serve as the energy metabolism reserve of cells but also participate in intracellular signal transduction and the development of inflammation and tumor. Lipid droplets are closely connected to and interact with various organelles, regulating the division, the transportation, and the genetics of organelles. The complexity of lipid droplets biogenesis and the diversity of their functions may have provided a physiological basis for the pathogenesis and development of diseases, but further research is needed in order to better understand the relevant processes. Published findings have helped elucidate the association between lipid droplets and diseases, such as obesity, non-alcoholic fatty liver disease, neurodegenerative disease, cancer, and cardiovascular disease, but the relationship between lipid droplets and oral diseases has not been fully studied. Topics that warrant further research include the role and mechanisms of lipid droplets in the pathogenesis and development of oral diseases, the relationship between oral diseases and systemic diseases, and translation of the effect of lipid droplets on oral diseases into valuable clinical diagnostic and treatment methods. Herein, we reviewed the biogenesis and functions of lipid droplets and the progress in research concerning lipid droplets in oral diseases, including mouth neoplasms, periodontitis, and dental caries.

Associations between dental caries and systemic diseases: a scoping review

BACKGROUND

The objective of this study was to evaluate and present evidence from animal and human clinical studies on associations between dental caries and systemic diseases, and to suggest potential mechanisms that might explain such associations.

METHODS

An electronic search was conducted of PubMed, Embase and Cochrane Central Register of Controlled Trials for articles published from 2010 to 2020 in the English language. From the initial search, 404 full-text studies were assessed for eligibility. After excluding studies for technical and study limitations, a total of 67 studies were included in the summary tables and additional studies were included in the review to support evidence.

RESULTS

Few systemic disease and conditions were found to be clinically meaningfully associated with caries experience. Best evidence from human and animal studies described association between metabolic diseases and dental caries. Several interesting animal studies were noted that could generate clinical hypotheses and further investigations in rodent models for cardiovascular injury and hyperglycemia. Inadequate data was found to suggest any modifications to current clinical practice or prevention guidelines.

CONCLUSIONS

Limited clinical evidence was found connecting several systemic diseases and dental caries. Inadequate data was found to suggest any modifications to current clinical practice or prevention guidelines.

CLINICAL SIGNIFICANCE

Understanding of associations between dental caries and systemic diseases play a crucial role in the treatment planning and education of the dental patient.

Relationship between impaired parasympathetic vasodilation and hyposalivation in parotid glands associated with type 2 diabetes mellitus

We examined the relationship between hemodynamics in the three major salivary glands and salivary secretion in urethane-anesthetized and sympathectomized type 2 diabetic and nondiabetic rats via laser speckle imaging and by collecting the saliva. Lingual nerve stimulation elicited rapid increases in glandular blood flow and induced salivary secretion from the three glands in both diabetic and nondiabetic rats. In the parotid gland, the magnitude of blood flow increase and salivary secretion was significantly lower in the diabetic rats when compared with the nondiabetic rats; however, this was not observed in the other glands. Although the intravenous administration of acetylcholine increased blood flow in the parotid gland in a dose-dependent manner, the response was significantly lower in the diabetic rats when compared with the nondiabetic rats. Similarly, mRNA expression levels of M1 and M3 muscarinic acetylcholine receptors in the parotid gland were relatively lower in the diabetic rats compared with the nondiabetic rats. Our results indicate that type 2 diabetes impairs parasympathetic vasodilation and salivary secretion in the parotid gland and suggest that disturbances in the cholinergic vasodilator pathway may contribute to the underlying mechanisms involved in the disruption of parasympathetic nerve-mediated glandular vasodilation.