A retrospective study on the prognostic factors and success, survival, and failure outcomes of treated endodontic-periodontal lesions.

OBJECTIVES: The objective of this retrospective study was to determine possible prognostic factors of endodontic-periodontal lesions and to compare success, survival, and failure outcomes of treated endodontic-periodontal lesions across different treatment modalities, demographic variables, and anatomical tooth variations. MATERIALS AND METHODS: Data was collected from patient records in the patient management system (Salud, Titanium Solutions) from the Griffith University Dental Clinic between January 2008 and December 2021. The search strategy used the terms "endodontic periodontal lesion," "periodontal endodontic lesion," "endo perio lesion," "perio endo lesion," and "EPL." The 88 cases which met inclusion and exclusion criteria were analyzed. RESULTS: The overall success rate was 46.6%, with 21.6% of teeth surviving and 31.8% of teeth failing. Bone loss extending to the apical third (OR = 0.3, 95% CI [0.104, 0.866]), and probing depths of 5-7 mm (OR = 0.147, 95% CI [0.034, 0.633]) and 8-10 mm (OR = 0.126, 95% CI [0.029, 0.542]) were associated with a statistically significant lower odds of success (p < .05). A history of no periodontal disease (OR = 7.705, 95% CI [1.603, 37.037]) was associated with a statistically significant higher odds of success (p < .05). CONCLUSION: Practitioners should be aware of bone loss to the apical third, deep probing depths, and a history of periodontal disease as possible prognostic factors that can affect the success rate when treating endodontic-periodontal lesions. Further research with more stringent control over operator factors should be done to investigate these variables.

Impact of root canal preparation using two single-file systems on the intra-radicular microbiome of teeth with primary apical periodontitis.

OBJECTIVES: This study aimed to describe the effects of two single-file systems on the diversity of the endodontic microbiome of teeth with primary asymptomatic apical periodontitis. MATERIALS AND METHODS: The root canals from single-rooted teeth with apical periodontitis were prepared using either the Reciproc Blue (RB) or the XP-endo Shaper (XPS) instrument system. The latter was followed by a supplementary step with the XP-endo Finisher (XPF) instrument. For irrigation, 5.25% sodium hypochlorite was used. Root canal samples were taken at the baseline (S1), after preparation (S2), and after the supplementary step (S3). DNA was extracted and subjected to high-throughput sequencing using the MiSeq Illumina platform. RESULTS: Samples from 10 teeth from the RB and 7 from the XPS group were subjected to DNA sequencing. Initial samples differed significantly from post-preparation samples in bacterial diversity, with no significant difference when comparing the two instrument systems. The most dominant phyla in S2 were Bacteroidetes, Proteobacteria, Firmicutes, Fusobacteria, and Actinobacteria. The same phyla were found to dominate baseline samples and samples taken after using XPF, but with differences in the ranking of the most dominant ones. At the genus level, the most dominant genera identified after RB instrumentation were Bacteroidaceae [G-1], Fusobacterium, and Staphylococcus, while the most dominant genera after XPS instrumentation were Fusobacterium and Porphyromonas. These genera were also dominant in the initial samples. CONCLUSIONS: Both treatment protocols had measurable effects on the root canal microbial diversity, with no significant differences between them. Most of the dominant taxa involved in the primary infection and probably in the aetiology of apical periodontitis were eliminated or substantially reduced. CLINICAL RELEVANCE: The most dominant taxa that persisted after instrumentation were Fusobacterium, Porphyromonas, Staphylococcus, and Bacteroidaceae [G-1].

Efficacy of an impression disinfectant solution after repeated use: An in vitro study.

Statement of problem: There are very few studies using Benzalkonium Chloride (BAC) as an active disinfection agent for immersion techniques and there are no studies investigating the efficacy of repeated use of a disinfectant solution. Purpose: This study evaluated an impression disinfectant by testing bacterial contamination of disinfectant batches used in a clinical setting after repeated use. Materials and methods: Liquid samples were collected from impression disinfectant solutions used to disinfect dental impressions taken at a university dental clinic. The experimental samples (500 ml from 1 L of solution) were collected from teaching and professional clinics and the in-house commercial processing laboratory and stored at room temperature each day of clinic operation over five weeks. To determine to what extent the disinfectant efficacy of the active product decreased over time, the following tests were carried out: a. Inoculation b. Gram staining technique c. Matrix Assisted Laser Desorption/Ionization Mass spectrometry (MALDI- MS). Microbial growth was monitored and photographed. A culture revival was made from colonies grown on sheep blood agar, to isolate pure colonies incubated for 24 h at 37 °C. Each morphologically distinct type of colony was gram stained and MALDI spectrometry analysis was performed using the VITEK MS (BioMerieux Inc.). Results: Evidence of growth of bacteria was detected in teaching clinics' samples, and no growth from the professional clinic or the commercial laboratory. Conclusions: The study demonstrated that the impression disinfectant solution tested is effective against common oral bacteria, despite some rare species such as Bacillus circulans, Bacillus horneckiae, Bacillus altitudinis/pumilus and Bacillus cereus showing evidence of survival in solutions used for disinfection of impressions. However, in a high use teaching clinic environment its efficacy deteriorated. Though a second level disinfection protocol in the commercial laboratory-maintained impression disinfection.

Effect of pulp capping materials on odontogenic differentiation of human dental pulp stem cells: An in vitro study.

OBJECTIVES: Migration and differentiation of human dental pulp stem cells (hDPSCs) is a vital and key factor in the success of reparative dentin formation for maintenance of pulp vitality. Pulp capping materials are used to stimulate DPSCs to induce new dentin formation. Thus, the aim of the present study was to compare the response of DPSCs to four commercially available pulp capping materials: a bioactive bioceramic (Material 1), a nonresinous ready-to-use bioceramic cement (Material 2), a bioactive composite (Material 3), and a biocompatible, dual-cured, resin-modified calcium silicate (Material 4). MATERIALS AND METHODS: hDPSCs were isolated and cultured from freshly extracted teeth and were then characterized by flow cytometry and multilineage differentiation. Discs prepared from pulp capping materials were tested with hDPSCs and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, cell migration assay and odontogenic differentiation assay was performed. Expression of osteogenic markers (osteopontin, RUNX family transcription factor 2, osteocalcin) and the odontogenic marker (dentin sialophosphoprotein) was detected using reverse transcription-polymerase chain reaction. RESULTS: Materials 1, 2, and 3 generated more cell viability than Material 4. Furthermore, Material 4 showed the least wound exposure percentage, while Material 3 showed the highest percentage. Enhanced mineralization was found in hDSCPs cultured with Material 3, followed by Material 1, and then Material 2, while Material 4 revealed the least calcified mineralization. CONCLUSIONS: The results of this study were inconclusive regards contemporary bioceramic materials designed for vital pulp therapy as they have different effects on hDPSC. Further testing for cytotoxicity using live-dead staining, animal experiments, clinical trials, and independent analyses of these biomaterials is necessary for clinicians to make an informed decision for their use.

In vitro effects of wool-derived keratin on human dental pulp-derived stem cells for endodontic applications.

In this study we examine the influence of wool-derived keratin intermediate filament proteins (kIFPs) on human dental pulp-derived stem cells (hDPSCs). kIFPs were diluted (10 mg/mL to 0.001 mg/mL) in cell culture media. Effects on hDPSCs proliferation were measured using Alamar blue assay. Keratin concentrations of 1 mg/mL and 0.1 mg/mL were tested for odontogenic differentiation and mineralisation. Alkaline phosphatase (ALP) quantification (7th, 14th, and 21st days), alizarin red S (AR-S) staining and calcium quantification (21st day), reverse transcription polymerase chain reaction (RT-PCR, collagen expression), and immunocytochemical staining for dentin matrix protein (DMP) were performed. hDPSCs showed higher proliferation with kIFPs of 0.1 mg/mL or less (p < 0.0001). The 0.1 mg/mL keratin concentration promoted odontogenic differentiation, confirmed by increased ALP activity, significant calcium deposits (AR-S staining, p < 0.05), up-regulated collagen expression (RT-PCR, p < 0.05), and positive DMP staining. These results suggest that kIFPs could be a potential biomaterial for pulp-dentin regeneration.

Material extrusion of thermoplastic acrylic for intraoral devices: Technical feasibility and evaluation.

With global demand for 3D printed medical devices on the rise, the search for safer, inexpensive, and sustainable methods is timely. Herein, we assessed the practicality of the material extrusion process for acrylic denture bases of which successful outcomes can be extended to implant surgical guides, orthodontic splints, impression trays, record bases and obturators for cleft palates or other maxillary defects. Representative materials comprising denture prototypes and test samples were designed and built with in-house polymethylmethacrylate filaments using varying print directions (PDs), layer heights (LHs) and reinforcements (RFs) with short glass fiber. The study undertook a comprehensive evaluation of the materials to determine their flexural, fracture, and thermal properties. Additional analyses for tensile and compressive properties, chemical composition, residual monomer, and surface roughness (Ra) were completed for parts with optimum parameters. Micrographic analysis of the acrylic composites revealed adequate fiber-matrix compatibility and predictably, their mechanical properties improved simultaneously with RFs and decreased LHs. Fiber reinforcement also improved the overall thermal conductivity of the materials. Ra, on the other hand, improved visibly with decreased RFs and LHs and the prototypes were effortlessly polished and characterized with veneering composites to mimic gingival tissues. In terms of chemical stability, the residual methyl methacrylate monomer contents are well below standards threshold for biological reactions. Notably, 5 vol% acrylic composites built with 0.05 mm LH in 0° on z-axis produced optimum properties that are superior to those of conventional acrylic, milled acrylic and 3D printed photopolymers. Finite element modeling successfully replicated the tensile properties of the prototypes. It may well be argued that the material extrusion process is cost-effective; however, the speed of manufacturing could be longer than that of established methods. Although the mean Ra is within an acceptable range, mandatory manual finishing and aesthetic pigmentation are required for long-term intraoral use. At a proof-of-concept level, it is evident that the material extrusion process can be applied to build inexpensive, safe, and robust thermoplastic acrylic devices. The broad outcomes of this novel study are equally worthy of academic reflection, and further translation to the clinic.

A 3-year qualitative evaluation of interprofessional team-based clinical education at an Australian dental school.

PURPOSE/OBJECTIVES: This article describes a qualitative evaluation of interprofessional (IP) team-based treatment planning (TBTP) involving dentistry, oral health therapy, dental prosthetics, and dental technology students at the Griffith University School of Dentistry and Oral Health (DOH). Using the same data from a recently published article that looked solely at the quantitative evaluation of TBTP, this article focuses on the qualitative evaluation of TBTP. This evaluation explores the contextual meaning related to the previously published aspects of TBTP that contributed positively toward oral health students' IP clinical learning and identifies themes reflecting students' IP clinical experience. METHODS: Thematic analysis of transcripts from nine focus groups, comprised of 46 final year students and open-ended questions collected from 544 students through an online instrument from 2012 to 2014, explored the question: "What is the contribution of IP student team-based processes on students' perceptions of IP learning and practice at DOH?" RESULTS: Responses from online participants and student focus groups revealed three major themes: useful role learning, communication confidence, and pro-active collaborative teamwork. Throughout each of these themes, students stated they possessed a confidence in collaborating with other oral health students as exhibited through an understanding of profession-specific and IP roles, self-assurance in communicating, and teamwork skills. CONCLUSION: Aspects of TBTP that contributed positively toward students' IP clinical learning and practice were meaningfully identified.

Overview of incorporation of inorganic antimicrobial materials in denture base resin: A scoping review.

STATEMENT OF PROBLEM: Dental hygiene for institutionalized patients and recurring Candida-associated denture stomatitis remain problematic because of a patient's limited dexterity or inability to eliminate Candida from denture surfaces. Although there has been extensive research into antimicrobial modification of denture base resins with inorganic materials, scoping reviews of the literature to identify knowledge gaps or efficacy of inorganic antimicrobial materials in denture base resins are lacking. PURPOSE: The purpose of this scoping review was to provide a synopsis of the efficacy of the major classes of inorganic antimicrobial materials currently incorporated into denture base resins. MATERIAL AND METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews was applied. Four electronic databases, including Embase, PubMed, Web of Science, and Google Scholar, were accessed for articles in the English language, up to February 2019, without restrictions on the date of publication. RESULTS: From the 53 articles selected, 25 distinguishable inorganic materials were found and divided into 3 subgroups. Forty-three articles evaluated nanomaterials, where mostly silver ion nanoparticles and/or titanium dioxide nanoparticles were incorporated into denture base resins. Fourteen articles examined antimicrobial drugs and medications, including azole group medications, amphotericin-B, Bactekiller, chlorhexidine, Novaron, and Zeomic. Two articles classified as others explored hydroxyapatite- and fiber-incorporated denture base resins. CONCLUSIONS: Although nanotechnology and antimicrobial medications or drugs have been successfully used to reduce Candida-associated denture stomatitis, long-term solutions are still lacking, and their disadvantages continue to outweigh their advantages.

Microbial Analysis of Obturators During Maxillofacial Prosthodontic Treatment Over an 8-Year Period.

The aim of the study was to investigate the microbial colonization (by Candida species, anaerobic and facultative anaerobic bacteria) of maxillary obturators used for the restoration of maxillary defects, including during radiotherapy.Retrospective cohort study.Fifteen patients requiring a maxillary obturator prosthesis had swabs of their obturators and adjacent tissues taken at different stages of their treatment over a period of 8 years.Identification of microbial species from the swabs was carried out using randomly amplified polymorphic DNA polymerase chain reaction (RAPD PCR) analysis, checkerboard DNA-DNA hybridization, CHROMagar Candida chromogenic agar, and DNA sequencing.Candida species were detected in all patients and all patients developed mucositis and candidiasis during radiotherapy which was associated with an increase in colonization of surfaces with Candida spp., particularly C albicans. Microbial colonization increased during radiotherapy and as an obturator aged, and decreased following a reline, delivery of a new prosthesis, or antifungal treatment during radiotherapy.Microbial colonization of maxillary obturators was related to the stage of treatment, age of the obturator material, radiotherapy and antifungal medications, and antifungal treatment may be recommended if C albicans colonization of palatal tissues is greater than 105 colony-forming units per cm2 following the first week of radiotherapy.

Trueness assessment of additively manufactured maxillary complete denture bases produced at different orientations.

STATEMENT OF PROBLEM: The trueness of the intaglio surface of an additively manufactured maxillary denture base may be influenced by the build orientation and the inclusion of support struts. PURPOSE: The purpose of this in vitro study was to compare the trueness of a photopolymer additively manufactured maxillary complete denture base created at different orientations with different support strut designs. Optimizing the build is critical for adopting best practice when fabricating maxillary complete dentures through additive manufacturing techniques. MATERIAL AND METHODS: Denture bases (N=70) were additively manufactured at 5 different build orientations (0-, 15-, 45-, 60-, and 90-degrees) with 10 specimens per orientation. Another 2 groups of 10 were manufactured by using the optimal printing orientation with and without support struts. The denture bases were scanned after storage in artificial saliva at 37 °C, and the scan data were analyzed with a 3D metrology software program. Statistical differences were determined with 1-way analysis of variance (ANOVA) and the Kruskal-Wallis test (α=.05). Color deviation heat maps were used to determine areas of clinically significant dimensional errors. RESULTS: Significant differences were found among groups for positive mean deviation (F=44.09, P<.001), negative mean deviation (F=11.69, P<.001), and root mean square deviation (F=17.11, P<.001) for the different orientations. One-way ANOVA revealed significant differences with the use of support struts in relation to negative mean deviation (F=3.857, P<.001) and RMSE (F=11.215, P<.001) and positive mean deviation (Kruskal-Wallis H=0.070, P=.007). The color deviation maps showed that a 45- to 90-degree print orientation was truest overall and that the addition of support struts to the cameo and intaglio surfaces improved the trueness of the maxillary denture bases. CONCLUSIONS: The build orientation and inclusion of support struts influenced the accuracy of the intaglio surface of additively manufactured maxillary denture bases. A 45- to 90-degree build orientation with support struts on the cameo and intaglio surfaces resulted in the truest denture base.

A 3-year quantitative evaluation of interprofessional team-based clinical education at an Australian dental school.

PURPOSE/OBJECTIVES: Clinical educational challenges led to the Griffith University School of Dentistry and Oral Health (DOH) introducing interprofessional team-based treatment planning (TBTP). This paper evaluates the interprofessional contribution made to student clinical learning and experience among dentistry, oral health therapy, dental prosthetics, and dental technology students. METHODS: A mixed methodology approach targeting 845 students collected data annually employing a prevalidated online instrument from 2012 to 2014 to answer the question: "What is the contribution of interprofessional student team-based processes on students' perceptions of interprofessional practice at DOH?" RESULTS: A representative study sample with a 64.4% response rate (N = 544) reported TBTP creating a supportive environment for interprofessional clinical learning. Significant improvements in learning shared across disciplines indicated improvements in mutual respect, understanding roles, and constructive communication enhancing teamwork. There were increasing significant correlations between shared learning and positive clinical experiences from 2012 (r = .642, p < .000) to 2013 (r = .678, p < .000) and 2014 (r = .719, p < .000). A combination of TBTP predictors accounted for 53% of the variance in clinical learning and experience in 2014 compared to 40% in 2012. CONCLUSION: Learning with other students, developing teamwork abilities, improved communication skills, and respect for other oral health professions were aspects of TBTP that positively impacted clinical learning and practice at DOH. Further study would assist to determine specific elements that made the greatest contribution to student learning experiences.

Bioenergetics of photobiomodulated osteoblast mitochondrial cells derived from human pulp stem cells: systematic review.

Dental pulp cells are a source of multipotent mesenchymal stem cells with a high proliferation rate and multilineage differentiation potential. This study investigated the photobiomodulated bioenergetic effects of mitochondria in osteoblasts that differentiated from human pulp stem cells. The systematic review followed PRISMA guidelines. The PICO question was formulated. Criteria for inclusion and exclusion were established prior to searches being performed on the PubMed/MEDLINE, Embase, and Scopus. Articles were identified and included if published in English within last 10 years; photobiomodulation or low-level laser therapy were discussed; the delivery parameters for dose and time were included and the studies focused on bioenergetics of osteoblast mitochondria. Studies excluded were non-human dental pulp tissue and in vivo studies. A total number of 110 articles were collated, 106 were excluded leaving a total of 4 articles. These studies demonstrated that in vitro use of photobiomodulation was performed using different laser and LED types; InGaAlP; InGaN; and InGaAsP with average wavelengths of 630 to 940 nm. Primary human osteoblastic STRO-1 and mesenchymal stem cell lineages were studied. Three out of four articles confirmed positive bioenergetic effects of photobiomodulation on mitochondria of osteoblasts derived from human pulp cells. This systematic review demonstrated a lack of adequate reporting of bioenergetics of osteoblast mitochondria after photobiomodulation treatment.

Fluorescence characteristics of E. faecalis in dentine following treatment with oxidizing endodontic irrigants.

INTRODUCTION: This study aimed to assess changes in the fluorescence characteristics of Enterococcus faecalis in human dentine over a period of 24 h following treatment with endodontic irrigants. METHOD: Sterilised, non-functional extracted third molars were embedded in acrylic resin and uniformly sectioned into 2 mm thick dentine sections. After the removal of smear layer, the dentine sections were inoculated with E. faecalis and cultured for 7 days. The infected dentine sections were subsequently treated with different concentrations of sodium hypochlorite (NaOCl) and hydrogen peroxide (H2O2). Bacterial fluorescence readings were assessed at different time points using a calibrated laser device. All data were assessed for normality (Kolmogorov Smirnoff test) and analysed using ANOVA with Bonferroni post-hoc tests. RESULTS: Fluorescence readings were quenched when E. faecalis infected human dentine sections were treated with oxidizing irrigants in vitro. Throughout a 24-hour period, fluorescence recovered in part but did not return to baseline level. CONCLUSION: The fluorescence quenching effect of these oxidizing agents needs to be considered when using laser fluorescence in assessing the quality of root canal debridement or disinfection.

Revised guidelines for the endodontic education of dentistry students in Australia and New Zealand (FEBRUARY 2021).

These revised guidelines for contemporary endodontic education in Australia and New Zealand (version 2021) propose the minimum criteria for the training of dentistry students. The document contains a definition of endodontics and a description of the scope of endodontics. It proposes a general outline for education programmes in endodontics as part of general dental practice.

Incorporation of antimicrobial agents in denture base resin: A systematic review.

STATEMENT OF PROBLEM: Denture base resins (DBRs), such as polymethyl methacrylate, are commonly used in the fabrication of removable dentures because of their physical, mechanical, and esthetic properties. However, the denture base acts as a substrate for microorganism adherence and biofilm formation, which may lead to denture stomatitis and be further complicated by fungal infections, of especial importance with geriatric and immunosuppressed patients. Therefore, methods to enhance the antimicrobial property of DBRs will be beneficial. PURPOSE: The purpose of this systematic review was to evaluate the literature on the antimicrobial activity of DBRs incorporating antimicrobial agents or materials. MATERIAL AND METHODS: A search of English peer-reviewed literature up to February 2019 reporting on antimicrobial activity of DBRs with respect to antimicrobial agents or materials, antimicrobial test effects and methods, and conclusion or knowledge gaps was conducted by using Embase, Google Scholar, PubMed, and Web of Science databases. Search terms included denture base resin and antibacterial, denture base resin and antifungal, and denture base resin and antimicrobial. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were applied for subsequent data analysis. RESULTS: Of 2536 identified articles, 28 met the inclusion criteria for the systematic review. Antimicrobial materials were divided into 3 groups: antimicrobial monomer or copolymer, phytochemical or phytomedical components, and other compounds. Strategies on how to incorporate these substances into DBRs and their impact on the reduction and prevention of the growth of microorganisms were identified. CONCLUSIONS: Although many efforts have been made to improve the antimicrobial ability of DBRs, this systematic review found that the effectiveness of incorporating of antimicrobial agents into DBRs has not been demonstrated conclusively.

In vivo bone regeneration assessment of offset and gradient melt electrowritten (MEW) PCL scaffolds.

BACKGROUND: Biomaterial-based bone tissue engineering represents a promising solution to overcome reduced residual bone volume. It has been previously demonstrated that gradient and offset architectures of three-dimensional melt electrowritten poly-caprolactone (PCL) scaffolds could successfully direct osteoblast cells differentiation toward an osteogenic lineage, resulting in mineralization. The aim of this study was therefore to evaluate the in vivo osteoconductive capacity of PCL scaffolds with these different architectures. METHODS: Five different calcium phosphate (CaP) coated melt electrowritten PCL pore sized scaffolds: 250 µm and 500 µm, 500 µm with 50% fibre offset (offset.50.50), tri layer gradient 250-500-750 µm (grad.250top) and 750-500-250 µm (grad.750top) were implanted into rodent critical-sized calvarial defects. Empty defects were used as a control. After 4 and 8 weeks of healing, the new bone was assessed by micro-computed tomography and immunohistochemistry. RESULTS: Significantly more newly formed bone was shown in the grad.250top scaffold 8 weeks post-implantation. Histological investigation also showed that soft tissue was replaced with newly formed bone and fully covered the grad.250top scaffold. While, the bone healing did not happen completely in the 250 µm, offset.50.50 scaffolds and blank calvaria defects following 8 weeks of implantation. Immunohistochemical analysis showed the expression of osteogenic markers was present in all scaffold groups at both time points. The mineralization marker Osteocalcin was detected with the highest intensity in the grad.250top and 500 µm scaffolds. Moreover, the expression of the endothelial markers showed that robust angiogenesis was involved in the repair process. CONCLUSIONS: These results suggest that the gradient pore size structure provides superior conditions for bone regeneration.

Revised guidelines for educational requirements for specialisation in endodontics in Australia and New Zealand (July 2020).

These revised guidelines developed by the Australian Society of Endodontology Inc. and the Australian and New Zealand Academy of Endodontists for educational requirements for specialisation in endodontics in Australia and New Zealand (version 2020) propose minimum criteria for training specialists in our field. The document contains a definition of endodontics and a description of the scope of endodontics. It proposes criteria for selection of the students and describes the proposed main features and a general outline of the education programme.

A Call for Action to Safely Deliver Oral Health Care during and Post COVID-19 Pandemic.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak started just a couple of months ago and it grew rapidly causing several deaths and morbidities. The mechanism behind the transmission of the virus is still not completely understood despite a multitude of new specific manuscripts being published daily. This article highlights the oral cavity as a possible viral transmission route into the body via the Angiotensin converting enzyme 2 receptor. It also provides guidelines for routine protective measures in the dental office while delivering oral health care.

Oxidising agents and its effect on human dentine fluorescence diagnostic measurements.

BACKGROUND: The ability to determine the effectiveness of root canal disinfection in real-time prior to the final root filling could significantly influence the management and treatment outcomes of root canal therapy. Laser fluorescence devices can detect bacterial fluorescence in real-time, however since quenching of fluorescence is a possible confounding factor, this study explored the effects of oxidising endodontic irrigants on laser fluorescence in dentine. METHODS: A total of 78 transverse 2 mm thick sections were prepared from the crowns of sterilised extracted non-functional third molars that had been embedded in acrylic resin. The dentine sections where then treated with different concentrations of sodium hypochlorite and hydrogen peroxide, with or without further rinsing with distilled water wash. Fluorescence values were recorded over 24 h using the DIAGNOdent laser fluorescence device. RESULTS: Both sodium hypochlorite and hydrogen peroxide cause quenching of fluorescence readings of human dentine, with reductions of 30-60% in fluorescence readings. The quenching effect occurred quickly, and recovery to baseline readings took from 1 h to 24 h. Rinsing with water reduced but did not eliminate the quenching effect. CONCLUSION: The use of laser fluorescence to reliably detect root canal bacteria porphyrins in real-time could significantly influence the management of teeth needing root canal therapy. This study highlighted the quenching effects of some root canal irrigants on human teeth root dentine, a variable that should be considered and controlled prior to using lasers to assist in assessing root canal sterility.

Silver Nanoparticles at Biocompatible Dosage Synergistically Increases Bacterial Susceptibility to Antibiotics.

Antibiotics used to treat bacterial infections can become ineffective over time or result in the emergence of antibiotic resistant pathogens. With the advent of nanotechnology, silver nanoparticles (AgNPs) have gained significant attention as a therapeutic agent due to the well-known antimicrobial properties of silver. However, there are concerns and limited literature on the potential cytotoxicity of nanoparticles at effective antimicrobial concentrations. AgNPs prepared from silver nitrate with glucose reduction were characterized by surface plasmon resonance, dynamic light scattering, zeta potential analysis and transmission electron microscopy. The cytotoxicity of AgNPs towards human gingival fibroblasts over 7 days was determined using cell proliferation assays and confocal microscopy. AgNP MIC and antibacterial effects alone and in combination with 11 antibiotics were determined against a panel of nine microbial species including gram-positive and gram-negative bacterial species. AgNPs concentrations ≤ 1 µg/mL were non-cytotoxic but also showed no antibacterial effects. However, when combined with each of eleven antibiotics, the biocompatible concentration of AgNPs (1 µg/mL) resulted in significant inhibition of bacterial growth for multiple bacterial species that were resistant to either the antibiotics or AgNPs alone. This study presents a promising strategy with further testing in vivo, to develop novel antimicrobial agents and strategies to confront emerging antimicrobial resistance.