Intrafibrillar silicification of collagen scaffolds for sustained release of stem cell homing chemokine in hard tissue regeneration.

Traditional bone regeneration strategies relied on supplementation of biomaterials constructs with stem or progenitor cells or growth factors. By contrast, cell homing strategies employ chemokines to mobilize stem or progenitor cells from host bone marrow and tissue niches to injured sites. Although silica-based biomaterials exhibit osteogenic and angiogenic potentials, they lack cell homing capability. Stromal cell-derived factor-1 (SDF-1) plays a pivotal role in mobilization and homing of stem cells to injured tissues. In this work, we demonstrated that 3-dimensional collagen scaffolds infiltrated with intrafibrillar silica are biodegradable and highly biocompatible. They exhibit improved compressive stress-strain responses and toughness over nonsilicified collagen scaffolds. They are osteoconductive and up-regulate expressions of osteogenesis- and angiogenesis-related genes more significantly than nonsilicified collagen scaffolds. In addition, these scaffolds reversibly bind SDF-1α for sustained release of this chemokine, which exhibits in vitro cell homing characteristics. When implanted subcutaneously in an in vivo mouse model, SDF-1α-loaded silicified collagen scaffolds stimulate the formation of ectopic bone and blood capillaries within the scaffold and abrogate the need for cell seeding or supplementation of osteogenic and angiogenic growth factors. Intrafibrillar-silicified collagen scaffolds with sustained SDF-1α release represent a less costly and complex alternative to contemporary cell seeding approaches and provide new therapeutic options for in situ hard tissue regeneration.

Submandibular gland and caries susceptibility in the obese Zucker rat.

BACKGROUND: Obesity is a prevalent disorder characterized as marked insulin resistance and low grade inflammation. We tested the hypothesis that obesity upregulates inflammatory markers in the submandibular gland in association with derangements of its architecture and pre-disposition to caries in obese Zucker rats (OZR). We also examined the potential impact of chromium picolinate (Cr(Pic)3), a nutritional supplement suggested to improve glycemic control, on the aforementioned parameters. DESIGN: Male OZR were treated with diets lacking and containing 5 or 10 mg/kg chromium (as Cr(Pic)3) from 6 weeks to about 6 months of age; lean Zucker rats (LZR) served as controls. Thereafter, glycemic status, salivary tissue architecture, and the levels of several inflammatory markers were determined in association with caries susceptibility. RESULTS: OZR showed reduced insulin sensitivity, increased ratio of phospho-nuclear factor-kappa B (NF-κB) to total NF-κB, and increased intercellular adhesion molecule-1 level but similar histological features compared to LZR. Importantly, compared to LZR, OZR displayed rampant caries and a tendency for reduced dentin mineral density. Treatment of OZR with Cr(Pic)3 attenuated upregulation of these proinflammatory indicators in association with reduced severity of caries without improving insulin sensitivity. CONCLUSIONS: Obesity promotes proinflammatory changes within the submandibular gland, without affecting glandular architecture, in association with rampant caries; Cr(Pic)3 treatment provided some protective effects.

Tooth Decay Prevention: Knowledge and Practices Survey of Dental Students.

OBJECTIVES: This study aimed to assess the level of knowledge, attitudes, and practices fissure sealants among undergraduate Saudi dental students. METHODS: A modified questionnaire consisted of 24-items was distributed among 226 undergraduate dental students, males and females of different years at Al-Farabi Colleges, Riyadh, Saudi Arabia. Chi-square/Fisher's exact tests were used for descriptive statistical analyses. RESULTS: The response rate was 100%. Most of the respondents were male (60.2) and (39.8%) were female. With regard to the level of study, 20.8% were in the fourth year, 43.8% in the fifth year, and 16.8% were in the sixth year. The respondents showed a sensible level of learning about sealants, with the majority (88%) believed that there is strong scientific evidence about fissure sealants effectiveness and around 90% showed a good understanding of sealant placement instructions. Furthermore, respondents demonstrated inadequate learning about sealants clinical practice. CONCLUSION: Despite a high proportion of undergraduate dental students' showed sufficient knowledge about dental sealant, following guidelines and standardized procedures in clinical practice is lacking. The findings suggest an urgent need of dental colleges to additionally and/or update their curriculum regarding fissure sealants to reflect advance dental education that concentrates on evidence-based practice (EBP) in Pediatric Dentistry and Dental Public Health need for regular continuing education courses for the dental professional. HOW TO CITE THIS ARTICLE: Al-Sabri FA, Ba-Salamah M, et al. Tooth Decay Prevention: Knowledge and Practices Survey of Dental Students. Int J Clin Pediatr Dent 2019;12(2):92-95.