Evaluation of Fracture Strength of Fiber-Reinforced Direct Composite Resin Restorations: An In Vitro Study.

This in vitro study aimed to compare the fracture strength of direct non-reinforced class II composite resin restorations and polyethylene fiber-reinforced restorations, and also to investigate the influence of the locations of polyethylene fibers within the cavity on the fracture strength. Sixty freshly extracted human teeth were disinfected and prepared (class II cavity design). The teeth were assigned randomly into four groups (n = 13). Group I (control) was restored with nano-hybrid composite resin. The other three experimental groups were restored with the same composite resin material reinforced by polyethylene fibers (Ribbond) at different locations. Fibers were placed either on the axial wall (Group II), on the gingival floor (Group III), or on the axial wall and pulpal/gingival floor (Group IV) of the proximal cavity. All the teeth were subjected to thermocycling to simulate the oral environment. The fracture strength was measured using a universal testing machine. Group IV had the highest mean fracture strength at maximum load (148.74 MPa), followed by Group II (140.73 MPa), Group III (136.34 MPa), and Group I (130.08 MPa), with a statistically significant difference from the control group (p = 0.008) but not between groups II and III.

Evaluation of Fluoride Release in Chitosan-Modified Glass Ionomer Cements.

OBJECTIVE: This study assessed the influence of chitosan nanoparticles on the fluoride-releasing ability of 4 glass ionomer cement (GIC) through an in vitro analysis. METHODS: Four types of GIC (type II light cure universal restorative, type II universal restorative, GC Fuji VII, and type IX) were modified with nanochitosan particles; 10% chitosan was added to the glass ionomer liquid. Six specimens for each of the 4 groups were created, using expendable Teflon moulds. Discs of each type of GIC (n = 6) were immersed in deionised water at various time intervals. Electrodes selective for fluoride ions were employed to analyse the amount of released fluoride at 1, 7, 14, 21, and 28 days. RESULTS: Chitosan-modified GICs showed greater fluoride release than conventional GICs at all time points. All samples showed an initial high release of fluoride that tapered off with time. The total amount of fluoride released increased from the 1st day to the 28th day on adding chitosan to all the 4 types of GIC. Amongst those, type IX high-strength posterior extra with chitosan released a considerably higher quantity of fluoride at all time intervals. CONCLUSIONS: In all the experimental groups, adding chitosan to the glass ionomer liquid had an accelerating effect on its fluoride-releasing property.

Dental Caries and Oral Health Status of Psychoactive Substance Abusers.

Substance-abuse disorders are universally associated with comorbid illness. Tobacco is a widely abused substance across the globe and presents a critical public health problem. The precise correlation between tobacco use and dental caries remains unclear. Thus, the present study aimed to evaluate the correlation between tobacco use and dental caries. METHODOLOGY: Based on selection criteria, a total of 270 (age 20-50 years) participants were included in the study, and were categorized as group A (n = 135), consisting of tobacco users, and group B (n = 135), comprising healthy controls (non-users). The Decayed, Missing, and Filled index (DMFT) was used to measure caries status. The Simplified Oral Hygiene index was used to evaluate oral health. RESULTS: The tobacco group reported the use of cigarettes; smokeless tobacco in indigenous forms, such as gutka (areca nut, tobacco, and slaked lime), betel nut chewing; and a combination. Individuals with tobacco habits had a higher prevalence of dental caries (Mean DMFT 4.73 ± 4.32) compared to the non-habit group (Mean DMFT 3.17 ± 3.11 (p = 0.001). The Oral Hygiene index was significantly higher (indicating bad/poor oral hygiene) in tobacco abusers than those of non-users (p = 0.0001). Duration and frequency of tobacco use were correlated with the levels of moderate and severe caries (p = 0.001). CONCLUSION: Psychoactive substance abuse, such as smoking/smokeless tobacco consumption, is associated with higher prevalence of dental caries.

Knowledge of COVID-19 Infection Guidelines among the Dental Health Care Professionals of Jazan Region, Saudi Arabia.

BACKGROUND: This study aimed to assess the knowledge about guidelines related to COVID-19 infection control procedures among dental health care professionals (DHCPs) in the Jazan region. METHODS: A cross-sectional study involving DHCPs (dental students, interns, and dentists) of the Jazan region between January and March 2021. A questionnaire with 35 items was developed and circulated online among the DHCPs. The dimensionality of the questionnaire was assessed using exploratory factor analysis (EFA). The level of awareness (LOA) was compared across the genders, level of professional experience, and exposure to guidelines. Participants were considered to have high LOA when they responded to 26 or more items correctly. RESULTS: A total of 363 DHCPs participated in the survey. The questionnaire was found to be valid and reliable. EFA revealed a distinct three-factor structure. Moreover, 61.2% of the respondents had high LOA related to COVID-19 infection prevention. Among those who had high LOA, dentists (65.5%) were relatively more than the students (62.5%) and interns (46.2%). Among the six guideline statements related explicitly to operative dentistry, more than 50% of the respondents were aware of 3 guideline statements, while less than 50% of the respondents were aware of the remaining statements. CONCLUSIONS: Most DHCP had a high LOA for general COVID-19 infection prevention and control guidelines. Dentists, males, and those who read the guidelines had higher LOA than their counterparts.

Effect of Ascorbic Acid on Differentiation, Secretome and Stemness of Stem Cells from Human Exfoliated Deciduous Tooth (SHEDs).

Stem cells from human exfoliated deciduous teeth (SHEDs) are considered a type of mesenchymal stem cells (MSCs) because of their unique origin from the neural crest. SHEDs can self-renewal and multi-lineage differentiation with the ability to differentiate into odontoblasts, osteoblast, chondrocytes, neuronal cells, hepatocytes, adipocytes, etc. They are emerging as an ideal source of MSCs because of their easy availability and extraordinary cell number. Ascorbic acid, or vitamin C, has many cell-based applications, such as bone regeneration, osteoblastic differentiation, or extracellular matrix production. It also impacts stem cell plasticity and the ability to sustain pluripotent activity. In this study, we evaluate the effects of ascorbic acid on stemness, paracrine secretion, and differentiation into osteoblast, chondrocytes, and adipocytes. SHEDs displayed enhanced multifaceted activity, which may have applications in regenerative therapy.