Radiographic Assessment of 121 Glass Fiber Post Procedures in 32 Patients Aged 21-60 Years Performed by 6th-Year Dental Students During the 2022-2023 Academic Year at the College of Dentistry, Jazan University, Saudi Arabia.

BACKGROUND The restoration of endodontically treated teeth (ETT) and severely damaged teeth has been a concern of clinicians. Glass Fiber Post (GFPs) combine the strength of carbon fiber posts with the esthetic appearance of glass to resemble natural dentin during dental restoration procedures. This radiographical study assessed the GFP carried out by students enrolled in the Clinical Comprehensive Course at the College of Dentistry, Jazan University. MATERIAL AND METHODS A total of 32 patients treated by 18 6th-year dental students with 121 GFPs were assessed in this cross-sectional radiographic study. The assessment covered tooth type, arch, post-to-root width, length of post in relation to the crown and root lengths, amount of remaining gutta percha (GP), and gap between GP and post. Data were analyzed using SPSS, and associations between variables were determined using the chi-square test. RESULTS Maxillary teeth were the most frequently restored with posts (88.4%) with most being (58.7%) anterior teeth, and 50.4% of posts had widths that were one-third that of the root. The percentage of posts was twice (71.1%) or equal to (26.4%) the crown length, whereas two-thirds of the tested GFPs were >5 mm of the remaining GP. Significant differences were observed in location and position of teeth with post width, post length in relation to crown or root length, and amount of remaining GP, with P values of 0.018, 0.000, and 0.001, respectively. CONCLUSIONS The assessed radiographs revealed that the performance of sixth year students in accomplishment GFP radiographically was satisfactory and within the values recommended in the literature.

A Systematic Review of Publications on Perceptions and Management of Chronic Medical Conditions Using Telemedicine Remote Consultations by Primary Healthcare Professionals April 2020 to December 2021 During the COVID-19 Pandemic.

Telemedicine technologies allow distribution of health-related services and information and can include electronic and telecommunication technologies, remote patient and clinician contact, referral and prescribing, patient education, and monitoring. This systematic review aimed to evaluate publications on the perceptions and management of chronic medical conditions using telehealth remote consultations by primary healthcare professionals between April 2020 and December 2021 during the COVID-19 pandemic. Electronic databases, including Cinhal, PubMed, Science Direct, and ProQuest were searched to extract qualitative studies relevant to the topic. Inclusion criteria were developed based on the Population, Exposure, and Outcomes scoping framework. The target population was healthcare professionals working in primary care settings. Included studies encompassed various types of telemedicine, such as synchronous telemedicine, video conferencing, telephone conversations, and smart devices. Eight studies were included. Synchronous telemedicine was highly effective in ensuring the continuity of care and treatment, providing patients with convenience, improved access to treatment, and earlier disease management. Video conferencing and telephone consultations were the most common methods used. Challenges included concerns about patient privacy, technology literacy, and acceptance. Telemedicine was commended for its ability to provide access to immediate expert medical advice and eliminate the need for long-distance travel, contributing to increased patient compliance. Synchronous telemedicine is a promising solution for managing chronic conditions during and after the COVID-19 pandemic, offering benefits to patients and healthcare professionals. To maximize its potential, concerns regarding patient privacy, confidentiality, and technology literacy need to be addressed. Proper legislation and regulations are required for long-term success of telemedicine, making it a valuable component of healthcare systems.

Evaluation of Cytotoxicity of Calcium Silicate-based Mineral Trioxide Aggregate Sealers: A Systematic Review of In Vitro Studies.

AIM: This review aimed to evaluate the in vitro studies done with regard to the cytotoxicity associated with mineral trioxide aggregate (MTA)-based root canal sealers. BACKGROUND: Root canal sealers are used during endodontic treatment as fillers to seal the gaps between the canal gutta-percha cone and canal walls. It is necessary to understand the cytotoxicity of these materials on human-derived cells as these materials interact with human cells periapically. REVIEW RESULTS: Six in vitro studies were chosen for review. In these selected studies, along with MTA-based root canal sealers, other sealers were tested for cytotoxicity on human periodontal ligament (PDL) stem cells, human PDL fibroblasts, and human osteoblast cells. Regarding cytotoxicity, the studies were diverse, and most were based on 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazolium bromide) (MTT) assay. In general, the studies suggested that root canal sealers cause mild to severe cytotoxic effects and that several factors influence this effect, such as material setting time, concentration, and duration of exposure. CONCLUSION: All studies in the review indicated that MTA. Fillapex must be used cautiously as it exhibited the highest cytotoxic effect compared to other MTA-based and non-MTA-based sealers. CLINICAL SIGNIFICANCE: Endodontic sealers do serve the purpose of bridging the gaps between the gutta-percha cone and the canal wall but knowing its biocompatibility becomes important as the material is extruded beyond the apical foramen where it comes in contact with the surrounding tissues. The effect of sealers on the surrounding tissues affects the healing and prognosis of the treatment.

Cherubism in Saudi population: a rare case report / Querubismo na população Saudi: relato de um caso raro

Cherubism is a rare hereditary benign fibro-osseous disorder characterised by bilateral swelling of the mandible and/or maxilla with varying severity of involvement. It occurs because of dominant mutations in SH3BP2 gene on the chromosome 4p16.3. On radiography cherubic lesions appear as multilocular cystic radiolucencies in the jaw bones giving a soap bubble appearance. These lesions usually heal by themselves by the time the patient attains puberty. Treatment is necessary only in aggressive cases where there is severe facial deformity or vital functions are hampered. Surgical corrections are preferred when the lesion is in its dormant phase. The aim of the present case report is to illustrate a case of cherubism in a 9-year-old Saudi boy which is a very rare occurrence as only 1 case of cherubism has been reported so far in the Saudi Arabian population (AU)

Querubismo é uma desordem fibro-óssea hereditária rara caracterizada por aumento de volume bilateral da mandíbula e/ou maxila com graus variáveis de severidade. Ocorre devido a mutação dominante no gene SH3BP2 no cromossomo 4p16.3. Radiograficamente as lesões de querubismo aparecem como radiolucência multilocular semelhantes a bolhas de sabão nos ossos maxilares. Geralmente as lesões involuem espontaneamente quando o paciente atinge a puberdade. O tratamento se faz necessário apenas nos casos mais agressivos que demonstram deformidade facial severa ou comprometimento de funções vitais. Correções cirúrgicas são preferíveis quando a lesão está na fase dormente. O objetivo do presente relato é ilustrar um caso de querubismo em um paciente de 9 anos da Arábia Saudita, sendo este um evento raríssimo com apenas um outro caso relatado na população da Arábia Saudita (AU)

Evaluation of Micro-Tensile Bond Strength of Fibre Post with Titanium Dioxide Nanoparticles as Fillers in Experimental Dental Composite Resin.

BACKGROUND: The clinical success of post-core restorations is determined by the composite utilized and the strength of the post-core adhesion. The effectiveness of titanium dioxide nanoparticles (TiO2 NPs) as a multifunctional material with photo-induced activities and better mechanical characteristics are observed as particle size is reduced to under 50 nm. AIM: The purpose of this study is to determine the bond strength of fibre-reinforced composite (FRC) posts with TiO2 NP as fillers and to compare it with conventional composite resin core material. MATERIALS AND METHODS: 30 single-rooted mandibular premolars were selected and routine root canal procedures were done. A quantity of 5% TiO2 NPs were synthesized and added as silanized filler to the experimental composite resin. Post space was prepared and fibre-reinforced composite (FRC) post luting was performed. The specimens were then grouped into the following groups: Group I consisted of the experimental composite resin containing 5% TiO2 fillers, Group II consisted of core X flow, and Group III consisted of Multicore Flow. All test groups were submitted for thermocycling. After this, the samples were tested for micro tensile bond strength. A stereomicroscope with a magnification of 20× was used to examine the fractured surfaces. The data were analysed using one-way ANOVA and Tukey HSD tests. RESULTS: Statistical analysis revealed that Group I showed the highest mean bond strength value of 35.6180 Mpa. The results obtained with Group III showed the lowest mean bond strength value of 19.4690 Mpa. Adhesive failures were identified by stereomicroscopy of the fractured surfaces. CONCLUSION: The experimental composite resin comprising 5% TiO2 NP had a greater bond to the FRC post than other materials tested.

Effect of Different Intracanal Medicaments on the Viability and Survival of Dental Pulp Stem Cells.

BACKGROUND: Stem cells play an important role in the success of regenerative endodontic procedures. They are affected by the presence of medicaments that are used before the induction of bleeding or the creation of a scaffold for endodontic regeneration. This study examines the effects of different intracanal medicaments on the viability and survival of dental pulp stem cells at different doses and over different exposure times. METHODS: Dental pulp stem cells were cultured from healthy third molar teeth using the long-term explant culture method and characterized using flow cytometry and exposed to different concentrations of calcium hydroxide, doxycycline, potassium iodide, triamcinolone, and glutaraldehyde, each ranging from 0 (control) to 1000 µg/mL. Exposure times were 6, 24, and 48 h. Cell viability was measured using the MTT assay, and apoptosis was measured using the Annexin V-binding assay. RESULTS: All medicaments significantly reduced cell viability at different concentrations over different exposure times. Calcium hydroxide and triamcinolone favored cell viability at higher concentrations during all exposure times compared to other medicaments. The apoptosis assay showed a significant increase in cell death on exposure to doxycycline, potassium iodide, and glutaraldehyde. CONCLUSION: The intracanal medicaments examined in our study affected the viability of dental pulp stem cells in a time and dose-dependent manner. They also adversely affected the survival of dental pulp stem cells. Further studies are needed to better understand the effect of prolonged exposure to medicaments according to clinical protocols and their effect on the stemness of dental pulp stem cells.

In-Silico modulation of Interleukin-8 (IL8) for the therapeutic management of endodontic pulpitis.

Emerging clinical evidences highlight the association of Interleukin-8 (IL8) with endodontic pulpitis. Relatively higher expression of IL8 has been found in the pulp samples of pulpitis patients with moderate/severe pain. It is speculated that IL8 can be considered as a potential target for therapeutics of endodontic pulpitis. A library consisting of 3072 small molecules from the ZINC database was used to identify potential lead molecules with drug-like properties against the IL8. Based on the in-silico structure-assisted drug designing involving molecular docking, MD simulations, and MMPBSA analyses, we found a small molecule ZINC14613097 inhibits IL8. This study provides a new lead molecule than can be further validated in in-vitro, in-vivo, and ongoing clinical studies for the therapeutic management of endodontic pulpitis.

Study of optimal conditions for growth and osteogenic differentiation of dental pulp stem cells based on glucose and serum content.

Dental pulp stem cells (DPSCs) have shown promising characteristics in terms of their proliferation and osteogenic differentiation potential, which could be of greater benefit in regenerative dentistry. However, obstacles remain in the in vitro cultivation of DPSCs, which significantly affect their growth and differentiating ability. Therefore in this study, we demonstrated the growth and osteogenic differentiation of DPSCs in the presence of media containing different combinations of serum and glucose to get an optimized combination of both. DPSCs were cultured in media containing combinations of low glucose (LG), low serum (LS), high glucose (HG), and high serum (HS). The proliferation and osteogenic differentiation were assessed in DPSCs cultured with these different combinations of culture conditions. High glucose high serum condition significantly inhibited the proliferation of DPSCs and also affected their clonogenic potential, as evidenced by colony-forming units. Irrespective of the serum content, high glucose in the media also decreased the osteogenic potential of DPSCs confirmed by functional staining, and downregulation of osteogenesis-related genes. High glucose content in the culture media affects the growth and differentiation potential of the DPSCs. Hence, the culture conditions for the DPSCs should be reconsidered to utilize their maximum potential.

Adipogenic Stimulation and Pyrrolidine Dithiocarbamate Induced Osteogenic Inhibition of Dental Pulp Stem Cells Is Countered by Cordycepin.

BACKGROUND: dental pulp-derived stem cells are easy to access and collect and are an excellent source of stem cells for regenerative therapy. These cells can interact with many biomolecules and scaffolds and can pass on the instructive signals to the sites of regeneration where they are used. In this regard cordycepin, a potential biomolecule derived from medicinal mushrooms with a spectrum of bioactive properties such as antioxidant, anti-inflammatory, and anticancer has not yet been tested for its effect on human dental pulp stem cells. OBJECTIVE: the objective of the present study was to assess the in vitro adipogenic and osteogenic differentiation potential of human dental pulp stem cells with or without induction after administration of cordycepin. MATERIALS AND METHODS: human dental pulp stem cells DPSCs were isolated from a healthy permanent tooth extracted for orthodontic purposes after obtaining informed consent. Flow cytometry technique was used to assess the surface markers of these cells such as CD73, CD90, and CD105, CD34, CD45, and HLA-DR. Further, an MTT assay was performed on the cells after subjecting them to various concentrations of cordycepin. Following this, the adipogenic and osteogenic potential of the dental pulp stem cells was assessed with or without induction under the influence/absence of 5 µM of cordycepin. The results obtained were statistically analyzed and documented. RESULTS: it was found that the dental pulp stem cells showed strong positive expression for CD73, CD90, and CD105 and faint expression of CD34, CD45, and HLA-DR. MTT assay revealed that 5 µM was the optimum concentration of cordycepin for all the assays. Concerning adipogenesis experiments, there was a statistically significant lowering of all the 4 adipogenesis-related genes PPARγ, FABP4, LPL, and C/EBPα following cordycepin treatment in the presence of induction compared to the only induction group and untreated control cells (p < 0.05). In connection with osteogenesis, was found that there was a statistically significant increase in the expression of RUNX2, COL1A1, OSX and OCN genes along with the increase in alkaline phosphatase and alizarin red staining in the DPSC treated with cordycepin along with the presence of induction and simultaneous addition of PDTC compared to the control untreated cells and cells treated with induction and simultaneous addition of PDTC (p < 0.05). CONCLUSION: cordycepin can be exploited for its osteopromotive properties and can be used as a bioactive molecule alongside the administration of dental pulp stem cells in the area of regenerative biology and medicine.

Dose-Dependent Effect of Cordycepin on Viability, Proliferation, Cell Cycle, and Migration in Dental Pulp Stem Cells.

OBJECTIVE: To examine the effect of Cordycepin on the viability, proliferation, and migratory properties of dental pulp-derived mesenchymal stem cells. MATERIALS AND METHODS: The pulp was derived from human premolar teeth extracted for orthodontic purposes after obtaining informed consent. The samples were transferred to the laboratory for processing. DPSCs were expanded and characterized using flow cytometry and differentiation to the bone, adipose, and cartilage cells was examined. MTT Assay was performed using various concentrations of Cordycepin. The growth curve was plotted for 13 days. Cell cycle analysis was performed by flow cytometry. Migratory ability was assessed by wound healing assay. ROS generation was detected by flow cytometry. Gene expression was quantified by RT-qPCR. Statistical analysis was performed. p < 0.05 was considered as significant and p < 0.01 was considered as highly significant (* p < 0.05, and ** p < 0.01). RESULTS: DPSCs expressed characteristic MSC-specific markers and trilineage differentiation. Cordycepin at lower concentrations did not affect the viability of DPSCs. The growth curve of cells showed a dose-dependent increase in cell numbers till the maximum dose. DPSCs treated with 2.5 µM Cordycepin was found to have a reduced G1 phase cell percentage. DPSCs treated with 2.5 µM and 5 µM Cordycepin showed a significant decrease in G2 phase cells. No significant difference was observed for S phase cells. Cordycepin treatment affected the migratory ability in DPSCs in a concentration-dependent manner. CONCLUSION: Cordycepin can be used at therapeutic doses to maintain stem cells.

Metformin pre-conditioning enhances the angiogenic ability of the secretome of dental pulp stem cells.

The aim of the present study was to assess the influence of metformin on the angiogenic ability of secretomes from dental pulp stem cells. The stem cells were obtained from the dental pulp (DPSCs) (n = 3) using the explant culture method. We treated the DPSCs with different concentrations of metformin and assessed the expression of the angiogenesis-related genes. We also tested the angiogenic effect of the secretomes on the yolk sac membrane of the chick embryos by counting the quaternary blood vessel formations on the yolk sac membrane. We found that metformin treatment enhanced the angiogenic potential of the stem cell secretome in a dose-dependent manner. This was evidenced by the increase in the quaternary blood vessel formations in the yolk sac membrane with lower to higher concentrations of metformin. Pre-treatment with metformin modulates the angiogenic potential of the stem cell-conditioned media in a dose-dependent manner. The augmentation of the angiogenic potential of the DPSCs can aid regeneration, especially in scenarios requiring the regeneration of vacuoles.

Small Molecule "Silmitasertib" Repurposed as Inhibitor of Transforming Growth Factor Beta 1 for the Development of Therapeutics for Oral Submucous Fibrosis.

Oral submucous fibrosis (OSMF) is considered a premalignant condition characterized by aggressive fibrosis of the submucosal tissues of the oral cavity reflecting its malignant transformation potential. Activation of transforming growth factor beta (TGF-ß) signaling has been reported to lead increased collagen production and fibrosis. Recently, significant upregulation of TGF-ß1 has been reported in OSMF as compared to normal tissues. Therefore, inhibition of the TGF-ß1 may pave for the development of therapeutics of OSMF. Based on the structure-assisted drug designing, we found "silmitasertib" as potent inhibitor of TGF-ß1. We suggest that this molecule can be validated and implemented for the treatment of OSMF.

Parathyroid Hormone Secretion and Receptor Expression Determine the Age-Related Degree of Osteogenic Differentiation in Dental Pulp Stem Cells.

OBJECTIVE: To demonstrate the levels of parathyroid hormone secretion and genetic expressions of parathyroid hormone (PTH) and PTH1 receptor (PTH1R) genes in the dental pulp stem cells (DPSCs) from different age groups before and after induction of osteogenic differentiation. In addition, we also wanted to check their correlation with the degree of osteogenic differentiation. METHODS: Human primary DPSCs from three age groups (milk tooth (SHEDs), 7-12 years old; young DPSCs (yDPSCs), 20-40 years old; old DPSCs (oDPSCs), 60+ years old) were characterized for mesenchymal stem cell (MSC) markers. DPSCs were subjected to osteogenic differentiation and functional staining. Gene expression levels were analyzed by qRT-PCR. Surface receptor analysis was done by flow cytometry. Comparative protein levels were evaluated by ELISA. RESULTS: All SHEDs, yDPSCs, and oDPSCs were found to be expressing mesenchymal stem cell markers. SHEDs showed more mineralization than yDPSCs and oDPSCs after osteogenic induction. SHEDs exhibited higher expression of PTH and PTH1R before and after osteogenic induction, and after osteogenic induction, SHEDs showed more expression for RUNX2, ALPL, and OCN. Higher levels of PTH were observed in SHEDs and yDPSCs, and the number of PTH1R positive cells was relatively lower in yDPSCs and oDPSCs than in SHEDs. After osteogenic induction, SHEDs were superior in the secretion of OPG, and the secretions of ALPL and PTH and the number of PTH1R positive cells were relatively low in the oDPSCs. CONCLUSIONS: The therapeutic quality of dental pulp stem cells is largely based on their ability to retain their stemness characteristics. This study emphasizes the criterion of aging, which affects the secretion of PTH by these cells, which in turn attenuates their osteogenic potential.

Effectiveness of Artificial Intelligence Applications Designed for Endodontic Diagnosis, Decision-making, and Prediction of Prognosis: A Systematic Review.

AIM: With advancements in science and technology, there has been phenomenal developments in the application of neural networks in dentistry. This systematic review aimed to report on the effectiveness of artificial intelligence (AI) applications designed for endodontic diagnosis, decision-making, and prediction of prognosis. MATERIALS AND METHODS: Studies reporting on AI applications in endodontics were identified from the electronic databases such as PubMed, Medline, Embase, Cochrane, Google Scholar, Scopus, and Web of Science, for original research articles published from January 1, 2000, to June 1, 2020. A total of 10 studies that met our eligibility criteria were further analyzed for qualitative data. QUADAS-2 was applied for synthesis of the quality of the studies included. RESULTS: A wide range of AI applications have been implemented in endodontics. The neural networks employed were mostly based on convolutional neural networks (CNNs) and artificial neural networks (ANNs) in their neural architectures. These AI models have been used for locating apical foramen, retreatment predictions, prediction of periapical pathologies, detection and diagnosis of vertical root fractures, and assessment of root morphologies. CONCLUSION: These studies suggest that the neural networks performed similar to the experienced professionals in terms of accuracy and precision. In some studies, these models have even outperformed the specialists. CLINICAL SIGNIFICANCE: These models can be of greater assistance as an expert opinion for less experienced and nonspecialists.

An in vitro Comparison of Antimicrobial Activity of Three Endodontic Sealers with Different Composition.

AIMS: The aim of the study was to compare the antimicrobial property of newly introduced EndoSequence BC sealer with commonly used zinc oxide-eugenol-based sealer (Zical) and epoxy resin-based sealer (MM-Seal) against Candida albicans, Lactobacillus, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. MATERIALS AND METHODS: The agar diffusion test was done to measure the antimicrobial activity of sealers. The sealers were put in the 4 mm wells prepared in the inoculated agar plates. The agar plates were incubated at 37°C for 24 hours and the zones of inhibition that appeared was measured. Chi-square test was done to evaluate intraobserver bias for all study samples. Intergroup comparison was done for all five parameters using Pearson correlation statistical analysis. RESULTS: EndoSequence BC sealer showed maximum mean of diameter of zones of inhibition against all the microorganisms but with no statistically significant difference with other sealers. Zical did not show any zone of inhibition against the P. aeruginosa. MM-Seal did not show any inhibitory activity against the P. aeruginosa and C. albicans. CONCLUSION: EndoSequence BC sealer showed antimicrobial activity against all the microorganisms and proved to be a better choice when compared with other two sealers. CLINICAL SIGNIFICANCE: Antimicrobial properties of endodontic sealers are important to prevent the persistent infection of the complex root canals. EndoSequence BC sealer has been proved to be a better sealer in this aspect.

In vitro comparison of antibacterial properties of bioceramic-based sealer, resin-based sealer and zinc oxide eugenol based sealer and two mineral trioxide aggregates.

OBJECTIVE: Our goal of the study was to evaluate the antibacterial properties of endodontic sealers against the E. faecalis. MATERIALS AND METHODS: Six millimeters wells were made for each material in all the preinoculated petri plates. Then, the petri plates were incubated for 24 h. The zones of inhibition appeared were measured, and the measurements were put to statistical analysis. RESULTS: EndoSequence BC Sealer, MM-mineral trioxide aggregate (MTA), and ProRoot MTA showed maximum means of diameter of zones of inhibition, whereas MM-seal and Endoseal did not show any zones of inhibition. CONCLUSION: EndoSequence BC Sealer was found to be a better endodontic sealer as compared to resin-based and zinc oxide-eugenol-based sealer.

Analysis of sugars and pH in commercially available soft drinks in Saudi Arabia with a brief review on their dental implications.

OBJECTIVE: To determine the amount of sugar and pH in commercially available soft drinks in Jazan, Saudi Arabia. This was further compared with their labeled values in order to inform the regulations. The effects of these drinks on teeth is reviewed. MATERIALS AND METHODS: Ten brands of popular soft drinks including 6 regular carbonated drinks and 4 energy drinks were obtained from the local markets. Their pH was determined using a pH meter. The amount of total sugar, glucose, fructose, and sucrose was estimated using high performance liquid chromatography (using Dionex ICS 5000 ion chromatography) at the Saudi Food and Drug Authority. Descriptive statistics was done to obtain the mean and standard deviation. Intergroup comparison was performed using independent t-test, and the labeled and estimated values within the group were compared with paired t-test. RESULTS: The labeled and estimated sugar in energy drinks (14.3 ± 0.48 and 15.6 ± 2.3, respectively) were higher than the carbonated drinks (11.2 ± 0.46 and 12.8 ± 0.99), which was statistically significant. In addition, there was a significant difference in the concentration of glucose in energy drinks (5.7 ± 1.7) compared to carbonated drinks (4.1 ± 1.4). The pH of these drinks ranged from 2.4 to 3.2. The differences between the estimated and labeled sugar in carbonated drinks showed statistical significance. Mild variation was observed in total sugar, glucose, fructose, and sucrose levels among different bottles of the same brand of these drinks. CONCLUSION: The low pH and high sugar content in these drinks are detrimental to dental health. Comparison of the estimated sugar with their labeled values showed variation in most of the brands. Preventive strategies should be implemented to reduce the health risks posed by these soft drinks.

A photochemical method for in vitro evaluation of fluid flow in human dentine.

OBJECTIVE: To evaluate the flow dynamics of dentine fluid using a chemiluminescence method in vitro. MATERIALS AND METHODS: Horizontally sliced coronal dentine specimens with thicknesses of 1.4, 1.6, 1.8, and 2.0mm (n=10 each) were prepared from extracted human third molars. After cleaning with EDTA, a mounted specimen was clamped between 2 acrylic chambers attached to both the occlusal and pulpal sides. The occlusal chamber, which was closed with a glass coverslip, was filled with a chemiluminescent solution (0.02% luminol and 1% sodium hydroxide in water). A trigger solution of 1% hydrogen peroxide and 1% potassium ferricyanide was injected into the pulpal chamber at a constant pressure of 2.5 kPa, and allowed to immediately flow into the patent dentinal tubules. Four consecutive measurements (T1-T4) were performed on each sample by recording the emission of chemiluminescence with a photodetector. The relationship between the crossing time of the liquid through the slice and dentine thickness was examined. RESULTS: An apparent time delay was detected between the starting points of the trigger solution run and photochemical emission at T1. Dt (Dt, s) values of each thickness group were 13.6 ± 4.25 for 1.4mm, 18.1 ± 2.38 for 1.6mm, 28.0 ± 2.46 for 1.8mm, and 39.2 ± 8.61 for 2.0mm, respectively. Dt significantly decreased as dentine became thinner towards the pulp chamber (P<0.001). CONCLUSIONS: The velocity of fluid flow increased both with increasing dentine depth or reduction of remaining dentine thickness.

Postural awareness among dental students in Jizan, Saudi Arabia.

OBJECTIVE: The study was conducted to assess the postural awareness of dental students in Jizan, Saudi Arabia. MATERIALS AND METHODS: Close-ended, self-administered questionnaires were used for data collection in the survey. The questionnaire was prepared by observing the positions of students working in the clinics and the common mistakes they make with regard to their postures. The questionnaires were distributed among the dental students who were present and reported to work in the clinics. Levels of postural awareness and the relationship between postural awareness and the degree of musculoskeletal disorder (MSD) among the students was evaluated. This study was carried out in the College of Dental Sciences and Hospital, Jizan. STATISTICAL ANALYSIS: The level of knowledge of postural awareness was evaluated and correlated with the presence or absence of the MSDs. Categorical variables were compared using Chi-square test. P values of less than 0.05 were considered statistically significant. RESULTS: A total of 162 dental students from the age group of 20-25 years were included in the survey, of which 134 dentists responded (83%). When their postural awareness was evaluated, results showed that 89% of the students had poor-to-medium levels of postural awareness. The relation between postural awareness and prevalence of MSDs indicated that 75% of the students with poor awareness, 49% of the students with average awareness, and 40% of the students with good awareness have MSDs. The results were statistically significant (0.002127, which is <0.005) stating that better awareness about proper postures while working helps to minimize the risk of MSDs. CONCLUSION: Evaluation of levels of postural awareness showed that 21% of the students had poor postural awareness, 67% had average awareness, and 11% had good postural awareness. The analysis of results showed that those students with low-to-average postural awareness had significantly greater prevalence of MSDs.