Harnessing the Regenerative Potential of Purified Bovine Dental Pulp and Dentin Extracellular Matrices in a Chitosan/Alginate Hydrogel.

When a tooth is diseased or damaged through caries, bioactive molecules are liberated from the pulp and dentin as part of the natural response to injury and these are key molecules for stimulating stem cell responses for tissue repair. Incorporation of these extracellular-matrix (ECM)-derived molecules into a hydrogel model can mimic in vivo conditions to enable dentin-pulp complex regeneration. Here, a chitosan/alginate (C/A) hydrogel is developed to sequester bovine ECM extracts. Human dental pulp cells (hDPCs) are cultured with these constructs and proliferation and cytotoxicity assays confirm that these C/A hydrogels are bioactive. Sequential z-axis fluorescent imaging visualizes hDPCs protruding into the hydrogel as it degraded. Alizarin red S staining shows that hDPCs cultured with the hydrogels display increased calcium-ion deposition, with dentin ECM stimulating the highest levels. Alkaline phosphatase activity is increased, as is expression of transforming growth factor-beta as demonstrated using immunocytochemistry. Directional analysis following phase contrast kinetic image capture demonstrates that both dentin and pulp ECM molecules act as chemoattractants for hDPCs. Data from this study demonstrate that purified ECM from dental pulp and dentin when delivered in a C/A hydrogel stimulates dental tissue repair processes in vitro.

In Vitro Models Used in the Formation of Root Caries Lesions-A Review of the Literature.

The management of root caries remains a challenge for clinicians due to its unique anatomical location and structure. There is increasing interest in utilising artificial root caries lesions to develop new strategies for remineralisation. An ideal protocol has not yet been agreed upon. The aim of this review is to provide a structured overview of previously reported in vitro root caries models. The literature was screened and mined for information mainly on substrate selection, model systems utilised, and variables used in the models. Human roots (60%) were the most frequently used substrates, followed by bovine roots (40%). Chemical models (69%) were the most frequently utilised model systems, followed by microbiological models (27%), to form root caries lesions. Acetate buffer solution (80%), pH 5.0 or above (40%), and a demineralisation time of five days (25%) were the common variables used in the chemical systems, while mono-species biofilm was most frequently used (73%) in microbiological models and Streptococcus mutans was the most common bacterial strain utilised in these models (80%). This review highlights the variability amongst the experimental approaches, discusses the advantages and limitations of these approaches, and emphasises that standardisation of experimental conditions along with sustained research will benefit root caries research.

Effects of glycation end-products on the dental pulp in patients with type 2 diabetes.

AIM: This ex vivo study aimed to compare protein expression of advanced glycation end-products (AGE) and receptor (RAGE), and the levels of selected genes associated with inflammation and collagen within dental pulp tissue from patients with type 2 (T2D) diabetes and non-T2D. METHODOLOGY: Noncarious extracted permanent molar teeth from patients with well-controlled T2D (n = 19) and non-T2D (controls) (n = 19) were collected and compared. The coronal pulp was examined using immunohistochemistry (IHC) (n = 10 per group) for anti-AGE and anti-RAGE. Quantitative PCR (n = 9 per group) was used to analyse the gene expression levels of NFKB, S100A12 and COLIA1. Data analyses were performed between the groups using GraphPad Prism using Pearson correlation, Shapiro-Wilk and Mann-Whitney U-tests, and multiple regression using SPSS. RESULTS: AGEs were distributed diffusely throughout the pulp extracellular matrix associated with collagen fibres and were present on several cell types. RAGE was expressed at the pulp-dentine interface and was observed on odontoblasts, immune cells, endothelial cells and fibroblasts. Semi-quantitative analysis of IHC samples showed significantly increased expression of AGE (p < .0001) and RAGE (p = .02) in T2D samples compared with controls. The expression of NFKB (p < .0001), S100A12 (p < .0001) and COLIA1 (p = .01) genes were significantly higher in the T2D pulp, and multivariate logistic regression analysis showed that these findings were not affected by age. CONCLUSION: T2D may exert a similar glycation response in the dental pulp to other body sites. This could occur through activation of NF-κB pathways with a concomitant increase in genes associated with inflammation and collagen.

Students' experience and perceptions of undergraduate endodontic education in New Zealand.

This study investigated the clinical experience and perceptions of New Zealand graduating dental students (2019 and 2020) towards endodontic teaching and their clinical learning outcomes using an online survey and clinical scenarios. Quantitative data were analysed using SPSS software, and qualitative data were analysed thematically. Responses were similar for both cohorts (response rates 74%, 2019; 73%, 2020). Endodontic teaching was valuable and interesting but difficult compared with other disciplines. Molar endodontics, finding canals and managing posture were challenging. Students felt more confident and less anxious when supervised by clinicians experienced in endodontics. Time management was the most anxiety-inducing factor and significantly related to clinical experience (p < 0.001). Overall, students appropriately applied knowledge in most areas of endodontics while holistic problem-solving in complex scenarios was variable. Maximising clinical experience and supervision from teachers experienced in endodontics are important for learning, improving confidence and reducing anxiety.

A Cell Culture Method for the Isolation and Study of Primary Human Dental Pulp Cells.

Primary human dental pulp cell (HDPC) cultures contain dental pulp stem cell (DPSC) populations. DPSCs are multipotent mesenchymal cells residing inside the dental pulp where they can contribute to the regenerative potential of this and other tissues throughout the body. These cells are promising tools for cell-based therapies, including regenerative endodontic procedures. HDPCs can be readily isolated and expanded from extracted teeth either by the dental tissue explant method or enzymatic digestion method. This chapter describes the explant method, whereby cells outgrow from dissected pulp tissue, to generate HDPC cultures. We also provide protocols for HDPC passaging, cryopreservation, and basic immunocytochemical characterization.

Potentiality and Inflammatory Marker Expression Are Maintained in Dental Pulp Cell Cultures from Carious Teeth.

OBJECTIVES: This investigation aimed to isolate and culture human dental pulp cells from carious teeth (cHDPCs) and compare their growth characteristics, colony-forming efficiency, mineralization potential and gene expression of Toll-like receptors (TLR)-2, TLR-4, TLR-9, tumour necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-6, IL-8, IL-17A, 1L-17R, IL-23A, nuclear factor-kappa B (NF-κB), mitogen-activated protein kinase (MAPK1), dentin matrix protein (DMP)-1, dentin sialophospho protein (DSPP), sex determining region Y-box 2 (SOX2) and marker of proliferation Ki-67 (MKi67) with cells isolated from healthy or non-carious teeth (ncHDPCs). METHODS: Pulp tissues were obtained from both healthy and carious teeth (n = 5, each) to generate primary cell lines using the explant culture technique. Cell cultures studies were undertaken by generating growth curves, a colony forming unit and a mineralization assay analysis. The expression of vimentin was assessed using immunocytochemistry (ICC), and the gene expression of above-mentioned genes was determined using quantitative real-time reverse-transcription polymerase chain reaction. RESULTS: ncHDPCs and cHDPCs were successfully isolated and cultured from healthy and inflamed human dental pulp tissue. At passage 4, both HDPC types demonstrated a typical spindle morphology with positive vimentin expression. No statistical difference was observed between ncHDPCs and cHDPCs in their growth characteristics or ability to differentiate into a mineralizing phenotype. ncHDPCs showed a statistically significant higher colony forming efficiency than cHDPCs. The gene expression levels of TLR-2, TLR-4, TLR-9, TNF-α, IL-6, IL-8, IL-17R, IL-23A, NF-κB, MAPK1, DMP1, DSPP and SOX2 were significantly higher in cHDPCs compared with ncHDPC cultures. CONCLUSION: cHDPCs retain their differentiation potential and inflammatory phenotype in vitro. The inflamed tooth pulp contains viable stem/progenitor cell populations which have the potential for expansion, proliferation and differentiation into a mineralizing lineage, similar to cells obtained from healthy pulp tissue. These findings have positive implications for regenerative endodontic procedures.

Type 2 diabetes and the clinically normal pulp: An in vitro study.

AIM: The aim of this study was to investigate the effect of type 2 diabetes (T2D) on clinically normal dental pulp tissue by using special stains and immunohistochemistry (IHC) to determine the morphology of the coronal pulp and distribution of immune markers in non-T2D and T2D groups. METHODOLOGY: Ethics approval for this in vitro pilot study was obtained from the University of Otago Human Ethics Committee (16/069). Twenty extracted permanent molar teeth diagnosed as having clinically normal pulp status were collected. Ten teeth were from participants with well-controlled T2D and ten from participants without diabetes (non-T2D). Each tooth was sectioned transversely at the cemento-enamel junction before the crowns were decalcified and embedded in paraffin. Sections were stained with haematoxylin and eosin, Massons trichrome, and van Gieson stains for histological and morphological evaluation. IHC using anti-CD4, anti-CD68 and anti-CD83 and anti-IL1ß, anti-IL6, anti-IL17, anti-TNF-α, anti-TLR2, anti-TLR4 and anti-FOXP3 identified proteins of interest. Qualitative and semi-quantitative analyses evaluated the morphology of the dental pulp and protein expression. Data analyses were performed with GraphPad Prism, using Student's t-test and multiple regression using SPSS at p < .05. RESULTS: Special stains demonstrated morphological differences in the T2D dental pulp compared with non-T2D. Qualitative analysis indicated that the pulp in the T2D samples was consistently less cellular, less vascular, showed evidence of thickened blood vessel walls, increased pulp calcification and collagen deposition. Semi-quantitative analysis of IHC samples showed the T2D pulp had significantly increased expression of macrophage and dendritic cell markers CD68 (p < .001) and CD83 (p = .04), and there was significantly greater expression of inflammatory cytokines IL1ß (p = .01), IL6 (p < .0001), IL17 (p < .0001) and TNF-α (p = .01). T2D samples showed a significant increase in markers of innate inflammation, TLR2 (p < .001) and TLR4 (p < .001) and decreased expression of regulatory T-cell marker, FOXP3 (p = .01). Multiple regression showed that age-corrected differences were statistically significant. CONCLUSION: Preliminary findings suggest that T2D may exert a similar response in the pulp to complications in other body sites. Hyperglycaemia is associated with changes in the morphology of the clinically normal dental pulp with altered immune cell and cytokine expression.

A critical review of in vitro research methodologies used to study mineralization in human dental pulp cell cultures.

BACKGROUND: The pulp contains a resident population of stem cells which can be stimulated to differentiate in order to repair the tooth by generating a mineralized extracellular matrix. Over recent decades there has been considerable interest in utilizing in vitro cell culture models to study dentinogenesis, with the aim of developing regenerative endodontic procedures, particularly where some vital pulp tissue remains. OBJECTIVES: The purpose of this review is to provide a structured oversight of in vitro research methodologies which have been used to study human pulp mineralization processes. METHOD: The literature was screened in the PubMed database up to March 2021 to identify manuscripts reporting the use of human dental pulp cells to study mineralization. The dataset identified 343 publications initially which were further screened and consequently 166 studies were identified and it was methodologically mined for information on: i) study purpose, ii) source and characterization of cells, iii) mineralizing supplements and concentrations, and iv) assays and markers used to characterize mineralization and differentiation, and the data was used to write this narrative review. RESULTS: Most published studies aimed at characterizing new biological stimulants for mineralization as well as determining the effect of scaffolds and dental (bio)materials. In general, pulp cells were isolated by enzymatic digestion, although the pulp explant technique was also common. For enzymatic digestion, a range of enzymes and concentrations were utilized, although collagenase type I and dispase were the most frequent. Isolated cells were not routinely characterized using either fluorescence-activated cell sorting (FACS) and magnetic-activated cell sorting (MACS) approaches and there was little consistency in terming cultures as dental pulp cells or dental pulp stem cells. A combination of media supplements, at a range of concentrations, of dexamethasone, ascorbic acid and beta-glycerophosphate, were frequently applied as the basis for the experimental conditions. Alizarin Red S (ARS) staining was the method of choice for assessment of mineralization at 21-days. Alkaline phosphatase assay was relatively frequently applied, solely or in combination with ARS staining. Further assessment of differentiation status was performed using transcript or protein markers, with dentine sialophosphoprotein (DSPP), osteocalcin and dentine matrix protein-1 (DMP -1), the most frequent. DISCUSSION: While this review highlights variability among experimental approaches, it does however identify a consensus experimental approach. CONCLUSION: Standardization of experimental conditions and sustained research will significantly benefit endodontic patient outcomes in the future.

Immunohistochemical and immunofluorescence expression profile of lymphatic endothelial cell markers in oral cancer.

Lymphangiogenesis makes an important contribution to the tumour microenvironment (TME), but little is known about this in oral squamous cell carcinoma (OSCC). Archival formalin-fixed paraffin-embedded specimens (28 OSCC, 10 inflamed and 6 normal oral mucosa controls) were processed using immunohistochemistry (IHC) with antibodies against lymphatic markers D2-40 (podoplanin), LYVE-1, VEGFR3 and Prox1. After the endothelial cells had been highlighted by the various markers for lymphatic endothelium, the positive stained cells and vessels were identified and counted in a systematic manner to determine microvessel density. Double-labelling immunofluorescence (DLIF) was used to investigate the specificity of D2-40 and LYVE-1 to lymphatic endothelial cells (LECs) as opposed to blood ECs. There was higher D2-40 and Prox1 lymphatic vessel density (P = .001) in the OSCC group when compared with both control groups. Some malignant keratinocytes expressed lymphatic markers, as did a much smaller number of epithelial cells in the control groups. DLIF showed that no vessels co-expressed D2-40/CD34 or LYVE/CD34. Some D2/40+ LVs were LYVE- . D2-40 was the most specific LEC marker in OSCC tissues. These results establish that the OSCC TME contains significantly more lymphatic vessels expressing D2-40 and Prox1 than the control groups, which may play a role in facilitating lymphatic invasion and metastases.

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.

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.

Curriculum development in final year dentistry to enhance competency and professionalism for contemporary general dental practice.

INTRODUCTION: General dentistry is the most common area of practice, and new dentists must have the competency and skills to safely deliver patient care. In New Zealand (NZ), completion of a 5-year Bachelor of Dental Surgery (BDS) degree enables graduates to register with the Dental Council in NZ. This necessitates that the clinical component of the curriculum in final year dentistry (BDS5) transparently delivers learning opportunities and evaluates competency for independent practice. A review of the BDS5 Clinical Practice course was undertaken in 2015 and a revised curriculum introduced in 2016. CURRICULUM: We present a BDS5 curriculum for a Clinical Practice course that is learner focused with emphasis on comprehensive patient-centred care, competency and professional practice. Learning opportunities and assessment processes are described alongside teacher training. These changes have provided students scaffolding to support clinical and professional development, and accommodate different learning preferences. The outcomes align with the competency requirements of the NZ regulatory body for registration as a general dental practitioner. Since its introduction 3 years ago, ongoing feedback from students and staff has been positive and indicates the curriculum is effective in achieving its objectives. CONCLUSIONS: This curriculum provides a firm foundation for students transitioning to independent clinical practice in the community and supports the professional development of clinical teachers. It may also be translated to other areas of health education to ensure the delivery of quality holistic patient care.

Vascularity and Angiogenic Signaling in the Dentine-Pulp Complex of Immature and Mature Permanent Teeth.

ABSTRACT. OBJECTIVE: This study aimed to examine the protein and gene expression of vascular endothelial growth factor (VEGF) and angiopoietins-1 and 2 in tissue from healthy and inflamed dental pulps. METHODS: Permanent teeth with pulps diagnosed as healthy or reversible pulpitis were used for immunohistochemistry (IHC) and gene expression experiments. For IHC, a whole pulp tissue was excavated from the pulp chamber, and it was formalin-fixed and processed for routine IHC with angiogenic markers anti-VEGF, anti-Ang1, and anti-Ang2. Staining was visualized with diaminobenzidine (DAB), and examined using light microscopy. The distribution of markers in healthy and inflamed pulps was qualitatively and quantitatively analyzed. Real-time quantitative polymerase chain reaction (RT qPCR) was used to ascertain the gene expression levels of ANGPT1, ANGPT2, and TEK in the presence of inflammation. Statistical analysis was performed using the Mann-Whitney test with the statistical significance level set at 0.05. RESULTS: There was increased protein and mRNA expression of VEGF and Ang-1 markers in inflamed pulp samples as compared with that in the healthy pulp tissue. IHC demonstrated intense expression of the VEGF protein on endothelial cells (EC) and some non-ECs, and there was significantly more staining on ECs associated with inflamed tissue (P<0.001). Ang-1 and Ang-2 were significantly expressed on ECs and non-ECs (P<0.05). RT qPCR did not show significant differences in gene expression between healthy and inflamed samples although similar trends were observed to IHC. CONCLUSION: The presence of Ang-1, Ang-2, VEGF, and TEK gene in healthy and mildly inflamed pulp tissue associated with reversible pulpitis indicates that these angiogenic factors may participate in physiological and pathological angiogenesis and healing. The inflammatory process may regulate Ang-1/Ang2/Tie2 signaling; and together with VEGF, these growth factors have an important role in modulating pulp angiogenesis.

Sealer penetration and adaptation in root canals with the butterfly effect.

The butterfly effect is a phenomenon seen in some roots and is related to density of dentinal tubules. The aim was to investigate penetration depth and adaptation quality of root canal sealers and ProRoot MTA into bucco-lingual and mesio-distal aspects of roots with and without the effect. One hundred and twenty teeth were decoronated at the cemento-enamel junction. Canals were prepared and assigned to obturation groups: gutta-percha with a sealer (AH Plus, EndoREZ, Kerr Pulp Canal Sealer, MTA Fillapex) or ProRoot MTA alone (each containing 10 butterfly and 10 non-butterfly roots). Root sectioning yielded coronal and middle samples. Confocal laser scanning and scanning electron microscopy were used to assess penetration and adaptation. Teeth with the effect had greater mean penetration bucco-lingually (766 µm) than mesio-distally (184 µm, P = 0.003). Coronal sections had greater penetration (430 µm) compared with middle (247 µm, P = 0.006). In conclusion, greater penetration in roots with the effect may improve treatment outcomes.

Crack Formation Following Root-End Preparation in Roots with the Butterfly Effect.

OBJECTIVE: To investigate apical cracks in roots that exhibit the butterfly effect and that have undergone apical resection and ultrasonic root-end cavity preparation. The effect of the obturation material was also studied. METHODS: Forty extracted single-rooted teeth were decoronated at the cemento-enamel junction. Roots were viewed under a light microscope and coded according to the presence or absence of the butterfly effect. Canals were prepared using ProTaper Next instruments to size X3 and assigned to two obturation groups (gutta-percha and AH Plus, and ProRoot MTA alone). Each contained twenty roots (10 with the butterfly effect and 10 without the butterfly effect). Roots were resected perpendicular to their long axis, 3 mm from the apex, and cavities were cut using ultrasonic retrotips. Resin replicas were used for crack imaging from scanning electron micrographs. Statistical analyses were performed using Stata 13.1 (StataCorp, College Station, TX, USA). RESULTS: Cracks occurred more frequently in teeth with the butterfly effect (80%), with this difference being significant (P=0.001). Most cracks (73%) ran buccolingually. Teeth obturated with MTA developed fewer cracks compared to those obturated with GP and sealer. CONCLUSION: Root-ends with the butterfly effect had a significantly higher number of buccolingual cracks following resection and ultrasonic root-end preparation. This might explain the development of some vertical root fractures, which usually run buccolingually. Canal obturation with MTA may be protective.

Vascularity and VEGF/VEGFR2 Signaling in the Dentine-Pulp Complex of Immature and Mature Permanent Teeth.

OBJECTIVE: To examine the microvessel density (MVD) and spatial distribution of endothelial cells and angiogenic activity in immature and mature permanent teeth using immunohistochemistry. METHODS: Healthy third molars with immature and mature root development were formalin-fixed, decalcified in 10% ethylenediaminetetraacetic acid, and processed for routine immunohistochemistry with endothelial cell markers anti-CD34 and anti-CD146 and angiogenic markers anti-vascular endothelial growth factor (VEGF) and anti-VEGF receptor-2 (VEGFR2). Staining was visualized with diaminobenzidine and examined using light microscopy. The distribution of markers was analyzed qualitatively and quantitatively in the coronal, middle, and apical regions of the dentine-pulp complex. RESULTS: There were spatial differences in protein expression for immature and mature teeth. The pulps of immature teeth were more vascular, had a greater number of CD34+ and CD146+ cells, and a significantly higher MVD in the coronal region than those of mature teeth (P=0.03). The apical papilla contained few blood vessels. VEGF/VEGFR2 activity was significantly greater for immature teeth (P=0.001). VEGF was expressed throughout the pulp-dentine complex, but there was significantly more growth factor coronally (immature P=0.04 and mature P=0.02). VEGFR2 was expressed less than VEGF but was seen on the endothelial cells and single cells unrelated to a vessel lumen. CONCLUSION: The spatial distribution of vascular and angiogenic (VEGF/VEGFR2) markers indicates the potential for altered healing responses in the pulps of immature and mature teeth. Immature teeth have a greater MVD and VEGF/VEGFR2 expression than mature teeth, and the increased expression of these markers in the coronal region of both tooth types is important for pulp healing.

Avulsion and replantation of a primary incisor tooth.

Avulsion of a primary tooth is a serious dental trauma, and the guidelines of the International Association of Dental Traumatology and textbooks in paediatric dentistry do not recommend replantation. Such management can result in severe damage to the supporting structures, and together with avulsion itself is commonly associated with developmental disturbances of the permanent tooth. We report the case of replantation in a 9-month-old child with a successful outcome, in a unique situation where conditions were optimal and careful long-term follow up was possible.

A new predoctoral endodontic module: evaluating learning and effectiveness.

The teaching of advanced endodontic courses at the predoctoral level is common, but it can be difficult to assess teaching effectiveness. Advanced modules placed later in the dental curriculum provide the opportunity to introduce a new topic, revisit and reinforce concepts learned previously, and instill the notion of lifelong learning. At any level, the introduction of new techniques to novices must be based on recognition of their prior knowledge and experience and their need for explicit direction, stepwise instruction, and comprehensive feedback. Assessment of students' performance should not only provide insights into what they know and can do, but also steer them towards desired outcomes. In addition, assessment can provide valuable feedback on teaching effectiveness. In this article, we describe a module piloted for inclusion in the University of Otago (New Zealand) fourth-year dental curriculum. This involved the use of tapered hand and rotary nickel-titanium files for root canal preparation and was taught through a didactic program (lectures and problem-based learning seminars) and a series of preclinical hands-on sessions. Findings from formative and summative assessments as well as student, peer, and self-evaluation indicated that the objectives of the module were met and that it was effective in both providing students with the basic skills for using this type of instrumentation and increasing their understanding and enthusiasm for endodontics. We conclude by discussing curriculum changes resulting from our module evaluation, directions for future research, and suggestions for teaching advanced endodontic techniques.

Maxillofacial fractures at Waikato Hospital, New Zealand: 1989 to 2000.

AIM: To describe the patterns of facial fractures presenting to a tertiary referral centre in New Zealand, and to identify risk indicators for maxillofacial trauma. METHOD: Clinical records of 2527 patients referred to a tertiary base hospital for the treatment of maxillofacial fractures from 1989 to 2000 were retrospectively analysed. Age, sex, ethnicity, cause of injury, anatomic location of facial fractures, alcohol involvement, and treatment received were recorded. RESULTS: The number of facial fractures treated by the Maxillofacial Unit at Waikato Hospital annually almost doubled over the 12-year study period (1989 to 2000). Eighty percent of those presenting with maxillofacial injuries were male, and 40% were aged between 15 and 24 years. Interpersonal violence and road traffic accidents were the most frequent causes of facial fractures. Alcohol consumption was associated with just over one-third of all cases, and was strongly associated with interpersonal violence. CONCLUSION: Presentation of patients with facial fractures at the Maxillofacial and Oral Surgery Unit at Waikato Hospital almost doubled over the 12 years. Risk indicators for presentation with a maxillofacial fracture included male gender, alcohol consumption, and interpersonal violence. There is an urgent need for appropriate health promotion to reduce interpersonal violence.

A comparison of phosphor-plate digital images with conventional radiographs for the perceived clarity of fine endodontic files and periapical lesions.

OBJECTIVE: We sought to compare digital images with radiographs for the perceived clarity of small endodontic file tips at 2 different working lengths, as well as for the visualization of periapical bone lesions. STUDY DESIGN: Standardized conventional radiographic and phosphor-plate digital images were taken of 20 extracted permanent mandibular molars with 06 K-files placed in the distal root canal either 2 mm short or flush with the apical foramen. Similar images were obtained from mandibles with teeth that demonstrated large (n = 10) or small (n = 10) periapical lesions. Four evaluators ranked the clarity of the digital image with that of the radiograph. Results were analyzed by using the 2-sided sign test, ordinal logistic regression, and the kappa test. RESULTS: The perceived clarity of an endodontic file tip, at any position, and of a small or large periapical lesion was significantly (P < .01) less on all digital images compared with conventional films. CONCLUSION: Evaluator ratings indicated that the perceived clarity of fine endodontic files and periapical lesions was significantly less with phosphor-plate digital images than with conventional radiographs.