Histological Evaluation of Pulpal Response and Dentin Bridge Formation After Direct Pulp Capping Using Recombinant Amelogenin and Mineral Trioxide Aggregate (MTA).

The purpose of the study was to compare and histologically investigate pulpal response and dentin bridge formation after direct pulp capping using recombinant amelogenin and mineral trioxide aggregate (MTA). Recombinant amelogenin protein and MTA were used as pulp capping materials in 120 teeth from eight mongrel dogs. Dogs were sacrificed at two different evaluation times. Regenerative changes were evaluated histologically. At two weeks, in contrast to the MTA group, most of the amelogenin group showed moderately formed hard tissue formation and the pulp tissue was completely filling the entire pulp chamber. These results were statistically significant. At two months, all the samples of the amelogenin group showed complete dentin bridge formation and the pulp chamber was filled entirely with tissue-mimicking the authentic pulp in all the specimens of the amelogenin group. These results were statistically significant. In conclusion, direct pulp capping by recombinant amelogenin protein resulted in significantly better regeneration of the dentin-pulp complex than MTA.

Antimicrobial Activity of Nanozirconium Oxide.

The goal behind this work is to prepare, characterize, and study the antimicrobial behavior of zirconia (ZrO2) nanoparticles (NPs). Various techniques, such as X-ray diffraction (XRD), were used for studying the mineralogical structure and crystal size. The microstructure and chemical composition of the prepared particles were analyzed using a scanning electron microscope attached with an energy-dispersive X-ray analysis (EDAX) unit. The antagonistic ability against several Gram-negative and Gram-positive bacteria, including Salmonella paratyphi, Pseudomonas aeruginosa, Alcaligenes aquatilis, Escherichia coli, Streptococcus pneumoniae, and Staphylococcus aureus, was assessed using the well diffusion method. The results of XRD and scanning electron microscopy (SEM) analyses revealed that the prepared material exhibited the phase of zirconium nanoparticles with particle sizes ranging between 40 and 75 nm. The antimicrobial test results demonstrated that the inhibitory effect increased with the increase of concentration. The inhibitory effect was more pronounced against Gram-positive bacteria, as indicated by the larger size of the inhibitory zone. At a 9% dimethyl sulfoxide (DMSO) concentration, the inhibitory zone had a diameter of 3.50 mm for S. aureus compared to a diameter of 3.40 mm for S. pneumoniae. The use of zirconium oxide nanoparticles reduced the diameter of the inhibitory zone when tested against S. aureus at a 3% DMSO concentration (0.50 mm diameter) and against S. pneumoniae (0.40 mm diameter). Zirconia nanoparticles were also evaluated for their antifungal activity against several species, including Aspergillus niger, Aspergillus flavus, and Penicillium sp. The size of the inhibitory zone indicated the susceptibility of microorganisms to nanozirconium oxide, resulting in a stronger inhibition of Penicillium sp. at a 100% DMSO concentration (4.50 mm diameter) compared to A. niger and A. flavus (3.00 mm diameter). The results for Penicillium sp. at a 3% DMSO concentration showed a diameter of the inhibitory zone of 0.90 mm, while for A. niger and A. flavus, the diameter was 0.80 mm. Thus, our findings demonstrate that the zirconium oxide nanoparticles possess the capability to reduce the inhibition zone effectively for both bacterial and fungal activities.

Antibacterial Activities of Ag/Cellulose Nanocomposites Derived from Marine Environment Algae against Bacterial Tooth Decay.

Dental caries is an infectious oral disease caused by the presence of different bacteria in biofilms. Multidrug resistance (MDR) is a major challenge of dental caries treatment. Swabs were taken from 65 patients with dental caries in Makkah, Saudi Arabia. Swabs were cultivated on mitis salivarius agar and de Man, Rogosa, and Sharpe (MRS) agar. VITEK 2 was used for the identification of isolated bacteria. Antibiotic susceptibility testing of the isolated bacteria was performed using commercial antibiotic disks. Ulva lactuca was used as a reducing agent and cellulose source to create nanocellulose and Ag/cellulose nanocomposites. Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction spectroscopy (XRD) were used to characterize nanocellulose and Ag/cellulose nanocomposites. The results showed that most bacterial isolates were Streptococcus spp., followed by Staphylococcus spp. on mitis salivarius media. Lactobacillus spp. and Corynebacterium group f-1 were the bacterial isolates on de Man, Rogosa, and Sharpe (MRS) media. The antibiotic susceptibility test revealed resistance rates of 77%, 93%, 0, 83%, 79%, and 79% against penicillin G, Augmentin, metronidazole, ampicillin, ciprofloxacin, and cotrimoxazole, respectively. Ag/cellulose nanocomposites and Ag/cellulose nanocomposites with fluoride were the most effective antibacterial agents. The aim of this work was to assess the antibacterial activity of Ag/cellulose nanocomposites with and without fluoride against bacteria isolated from the oral cavities of patients with dental caries. This study demonstrated that Ag/cellulose nanocomposites have antibacterial properties against multidrug-resistant bacteria that cause dental caries.

Biocompatibility and Antibacterial Action of Salvadora persica Extract as Intracanal Medication (In Vitro and Ex Vivo Experiment).

This study aimed to test the biocompatibility and antibacterial properties of Salvadora persica (S. persica) extract, a natural product, as an intracanal medication in comparison with calcium hydroxide (Metapaste, META BIOMED, Cheongju, Korea). The pH values of both materials were tested. The biocompatibility of S. persica extract and Metapaste was determined using light microscopy and MTT assays. The antibacterial action was tested using the zone of bacterial inhibition on four common bacterial species. In addition, intracanal medication was administered using 68 extracted single-rooted teeth contaminated with Enterococcus faecalis (E. faecalis), and the percentage reduction in colony count (% RCC) at 1, 3, and 7 days was measured. The extension of activity for both materials was assessed using histological sections and scanning electron microscopy. S. persica was found to be acidic in nature. Both materials showed significantly lower cell viability than the positive control cells on days 1 and 3 but not on day 7. S. persica showed better antibacterial effects against E. faecalis and S. mutans. S. persica extract showed 97.6%, 98.9%, and 99.3% RCC values at 1, 3, and 7 days, respectively, which are comparable to those of Metapaste. S. persica herbal extract is a promising material that can be utilized as an intracanal medication, but its use requires further research.

Elevated Expression of Macrophage Migration Inhibitory Factor Promotes Inflammatory Bone Resorption Induced in a Mouse Model of Periradicular Periodontitis.

Locally produced osteoclastogenic factor RANKL plays a critical role in the development of bone resorption in periradicular periodontitis. However, because RANKL is also required for healthy bone remodeling, it is plausible that a costimulatory molecule that upregulates RANKL production in inflammatory periradicular periodontitis may be involved in the pathogenic bone loss processes. We hypothesized that macrophage migration inhibitory factor (MIF) would play a role in upregulating the RANKL-mediated osteoclastogenesis in the periradicular lesion. In response to pulp exposure, the bone loss and level of MIF mRNA increased in the periradicular periodontitis, which peaked at 14 d, in conjunction with the upregulated expressions of mRNAs for RANKL, proinflammatory cytokines (TNF-α, IL-6, and IL-1ß), chemokines (MCP-1 and SDF-1), and MIF's cognate receptors CXCR4 and CD74. Furthermore, expressions of those mRNAs were found significantly higher in wild-type mice compared with that of MIF-/- mice. In contrast, bacterial LPS elicited the production of MIF from ligament fibroblasts in vitro, which, in turn, enhanced their productions of RANKL and TNF-α. rMIF significantly upregulated the number of TRAP+ osteoclasts in vitro. Finally, periapical bone loss induced in wild-type mice were significantly diminished in MIF-/- mice. Altogether, the current study demonstrated that MIF appeared to function as a key costimulatory molecule to upregulate RANKL-mediated osteoclastogenesis, leading to the pathogenically augmented bone resorption in periradicular lesions. These data also suggest that the approach to neutralize MIF activity may lead to the development of a therapeutic regimen for the prevention of pathogenic bone loss in periradicular periodontitis.

Knowledge and attitude of emergency physician about the emergency management of tooth avulsion.

BACKGROUND: The aim of the study was to evaluate the knowledge of ER physicians with different specialties, experience and hospital sectors for the management of avulsed teeth in the emergency rooms of eight major hospitals in Jeddah, Saudi Arabia. It also covers their attitude towards receiving further education on tooth avulsion management. METHODS: A cross-sectional survey was conducted at the emergency rooms of eight hospitals in Jeddah from August to December 2015. A self-administered questionnaire consisting of 31 multiple choice questions assessing both knowledge and attitude was distributed to 150 physicians who were working in the ER departments. RESULTS: Response rate was 81.33%. Data revealed that 45.9% of the respondents did not have prior knowledge about avulsion. Physicians working in military hospitals had better knowledge about the ER management of avulsion cases than physicians of public hospitals. 80.3% of participants showed willingness to replant the tooth, however, 65.3% would not do it by themselves. 42.6% of the physicians did not know the importance of extra-oral time. Milk was selected as the best transport media for avulsed tooth by 31.1% of the participants. Regarding physicians' attitude, 95.1% showed interest in receiving information about the subject. CONCLUSION: This study revealed that the majority of ER physicians lack the knowledge needed to manage avulsions cases. Hence, educational programs are necessary for ER physicians to provide proper management for those cases.

Cutoff score evaluation of undergraduate dental curriculum.

BACKGROUND AND OBJECTIVES: Exams at the Faculty of Dentistry (KAUFD) are usually constructed to match King Abdulaziz University (KAU) policy of a fixed 60% cutoff score, though they have never been tested or evaluated. The purpose of this study was to validate the cutoff scores of three final fifth-year written exams of the undergraduate Endodontic course to assess whether they were similar to KAU regulation using the Angoff rating method. DESIGN AND SETTINGS: This study was conducted between May 2014 and February 2015 at the Faculty of Dentistry, King Abdulaziz University. METHODS: Using the Angoff rating method, three final fifth-year undergraduate Endodontic written exams were evaluated by four senior faculty members. RESULTS: The cutoff scores for exams 1, 2 and 3 were 57.4%, 62.9% and 63.1%, respectively. Adjusting the exams' cut off scores would cause changes in some students' results. CONCLUSIONS: Although the cutoff scores for all exams were close to 60%, slight deviation from the accepted cutoff score could definitely affect the students' results. Therefore, all exams should be validated before being given to students to certify that the cutoff score is credible and defensible.

Scholar outcomes for dental internship research program in Saudi Arabia: A qualitative evaluation.

OBJECTIVE: To explore the potential, challenges and needs for internship research activities in achieving scholar outcomes among graduates. METHODS: A qualitative general needs assessment and evaluation of an internship research program was conducted at King Abdulaziz University, Faculty of Dentistry (KAUFD), KSA, from December 2014 to February 2015 using focus groups and interviews. The participants included: administrates, faculty, and internship students. Data were transcribed and analyzed following the grounded theory. RESULTS: The participants were two administrative personnel, 21 faculty members, and 16 internship students. Results were clustered around five main domains; curriculum design, faculty, students, administrative, and institutional domain. Reported potentials included: a multi-faceted educational intervention approach, and building evidence-based skills and inquiry minds among graduates. Time, load, and incentives were major challenges reported by faculty. Interesting and achievable research topics were major challenges reported by students. Areas that needed development included: equipped research personnel, aligned administrative and institutional support, faculty skills, students' knowledge and skills, aligned curriculum, and clear program goals, objectives, and outcomes. CONCLUSION: Curriculum design, faculty and students' skills; as well as administrative and institutional support were found to play major roles in the success of the current internship research program at KAUFD.

Comparison Between Dexamethasone and Ibuprofen for Postoperative Pain Prevention and Control After Surgical Implant Placement: A Double-Masked, Parallel-Group, Placebo-Controlled Randomized Clinical Trial.

BACKGROUND: Postoperative pain is a potential adverse side effect of oral surgeries, and attempts should be made to prevent or minimize it. This study compares efficacy of preemptive ibuprofen and dexamethasone protocols for pain prevention or control after surgical implant placement. METHODS: This prospective, double-masked, parallel-group, placebo-controlled, randomized clinical trial included 117 patients with planned dental implant placement. Patients were assigned to receive one of three different protocols: 1) 600 mg ibuprofen 1 hour before surgery and another 600 mg 6 hours after the first dose; 2) 4 mg dexamethasone 1 hour before surgery and another 4 mg 6 hours after the first dose; or 3) placebo. Rescue medication (1,000 mg acetaminophen) was made available to each patient, and they were instructed to take it as necessary. Pain intensity was evaluated via a 101-point numeric rating scale and a visual analog scale, and discomfort was evaluated using a four-point verbal rating scale hourly for the first 8 hours after surgery and three times daily for the following 3 days. RESULTS: Ibuprofen and dexamethasone significantly reduced pain (Kruskal-Wallis; P <0.05) up to 3 days after surgery and discomfort (P <0.05) up to 2 days after surgery compared with placebo treatment. Both treatments reduced the number of painkillers taken and increased time before the first painkiller was taken (P <0.01). CONCLUSION: Steroidal dexamethasone is as effective as non-steroidal ibuprofen for preventing or controlling postoperative pain and discomfort after surgical implant placement.

Elevated CD14 (Cluster of Differentiation 14) and Toll-Like Receptor (TLR) 4 Signaling Deteriorate Periapical Inflammation in TLR2 Deficient Mice.

Apical periodontitis (periapical lesions) is an infection-induced chronic inflammation in the jaw, ultimately resulting in the destruction of apical periodontal tissue. Toll-like receptors (TLRs) are prominent in the initial recognition of pathogens. Our previous study showed that TLR4 signaling is proinflammatory in periapical lesions induced by a polymicrobial endodontic infection. In contrast, the functional role of TLR2 in regulation of periapical tissue destruction is still not fully understood. Using TLR2 deficient (KO), TLR2/TLR4 double deficient (dKO), and wild-type (WT) mice, we demonstrate that TLR2 KO mice are highly responsive to polymicrobial infection-induced periapical lesion caused by over activation of TLR4 signal transduction pathway that resulted in elevation of NF-kB (nuclear factor kappa B) and proinflammatory cytokine production. The altered TLR4 signaling is caused by TLR2 deficiency-dependent elevation of CD14 (cluster of differentiation 14), which is a co-receptor of TLR4. Indeed, neutralization of CD14 strikingly suppresses TLR2 deficiency-dependent inflammation and tissue destruction in vitro and in vivo. Our findings suggest that a network of TLR2, TLR4, and CD14 is a key factor in regulation of polymicrobial dentoalveolar infection and subsequent tissue destruction. Anat Rec, 299:1281-1292, 2016. © 2016 Wiley Periodicals, Inc.

Macrophage Migration Inhibitory Factor (MIF) Supports Homing of Osteoclast Precursors to Peripheral Osteolytic Lesions.

By binding to its chemokine receptor CXCR4 on osteoclast precursor cells (OCPs), it is well known that stromal cell-derived factor-1 (SDF-1) promotes the chemotactic recruitment of circulating OCPs to the homeostatic bone remodeling site. However, the engagement of circulating OCPs in pathogenic bone resorption remains to be elucidated. The present study investigated a possible chemoattractant role of macrophage migration inhibitory factor (MIF), another ligand for C-X-C chemokine receptor type 4 (CXCR4), in the recruitment of circulating OCPs to the bone lytic lesion. To accomplish this, we used Csf1r-eGFP-knock-in (KI) mice to establish an animal model of polymethylmethacrylate (PMMA) particle-induced calvarial osteolysis. In the circulating Csf1r-eGFP+ cells of healthy Csf1r-eGFP-KI mice, Csf1r+/CD11b+ cells showed a greater degree of RANKL-induced osteoclastogenesis compared to a subset of Csf1r+/RANK+ cells in vitro. Therefore, Csf1r-eGFP+/CD11b+ cells were targeted as functionally relevant OCPs in the present study. Although expression of the two cognate receptors for MIF, CXCR2 and CXCR4, was elevated on Csf1r+/CD11b+ cells, transmigration of OCPs toward recombinant MIF in vitro was facilitated by ligation with CXCR4, but not CXCR2. Meanwhile, the level of PMMA-induced bone resorption in calvaria was markedly greater in wild-type (WT) mice compared to that detected in MIF-knockout (KO) mice. Interestingly, in contrast to the elevated MIF, diminished SDF-1 was detected in a particle-induced bone lytic lesion of WT mice in conjunction with an increased number of infiltrating CXCR4+ OCPs. However, such diminished SDF-1 was not found in the PMMA-injected calvaria of MIF-KO mice. Furthermore, stimulation of osteoblasts with MIF in vitro suppressed their production of SDF-1, suggesting that MIF can downmodulate SDF-1 production in bone tissue. Systemically administered anti-MIF neutralizing monoclonal antibody (mAb) inhibited the homing of CXCR4+ OCPs, as well as bone resorption, in the PMMA-injected calvaria, while increasing locally produced SDF-1. Collectively, these data suggest that locally produced MIF in the inflammatory bone lytic site is engaged in the chemoattraction of circulating CXCR4+ OCPs. © 2016 American Society for Bone and Mineral Research.

The antimicrobial activity of the appetite peptide hormone ghrelin.

The present study examined the antimicrobial activity of the peptide ghrelin. Both major forms of ghrelin, acylated ghrelin (AG) and desacylated ghrelin (DAG), demonstrated the same degree of bactericidal activity against Gram-negative Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa), while bactericidal effects against Gram-positive Staphylococcus aureus (S. aureus) and Enterococcus faecalis (E. faecalis) were minimal or absent, respectively. To elucidate the bactericidal mechanism of AG and DAG against bacteria, we monitored the effect of the cationic peptides on the zeta potential of E. coli. Our results show that AG and DAG similarly quenched the negative surface charge of E. coli, suggesting that ghrelin-mediated bactericidal effects are influenced by charge-dependent binding and not by acyl modification. Like most cationic antimicrobial peptides (CAMPs), we also found that the antibacterial activity of AG was attenuated in physiological NaCl concentration (150mM). Nonetheless, these findings indicate that both AG and DAG can act as CAMPs against Gram-negative bacteria.