Epidemiology of odontogenic tumours and selected cysts diagnosed at a single New Zealand oral pathology centre- A 15-year retrospective study.

PURPOSE: This research aimed to investigate the relative frequency of odontogenic tumours (OT) and selected odontogenic cysts in a single oral pathology center in New Zealand from 2008 to 2023. METHODS: Histopathological records from the Oral Pathology Centre, University of Otago (2008-2023) were examined to identify OT. Odontogenic keratocyst (OKC) and calcifying odontogenic cyst (COC), previously classified as OT were also included. Patient demographics, clinical details and histopathologic diagnoses were recorded. Data were analyzed using SPSS. RESULTS: Of the 34,225 biopsies over the 15-year period, 1.8% were identified as OTs, COC and OKCs and accounted for 47%, 1.5% and 51.5% respectively. The most prevalent OT types were odontoma (43.7%), ameloblastoma (27%) and cemento-ossifying fibroma (7.5%). Malignant OT, ameloblastic carcinoma, constituted 1.4% of OT. The average age at diagnosis for OKC, COC and OT patients were 48.2 ± 20.9, 33.7 ± 23.3 and 28.9 ± 19.3 years. Overall, male and mandibular site predilections were observed. Recurrence of OKC and ameloblastoma occurred in 15.2% and 13.7% of patients. The time for recurrence for OKC and Ameloblastoma were 61.7 ± 56.5 months and 122 ± 152 months respectively. CONCLUSION: The demographic features and range of OT, COC and OKC in New Zealand align with those of other western countries. The study also confirms need for long term follow up for patient with OKC and ameloblastoma.

Concordance of clinician, Chat-GPT4, and ORAD diagnoses against histopathology in Odontogenic Keratocysts and tumours: a 15-Year New Zealand retrospective study.

BACKGROUND: This research aimed to investigate the concordance between clinical impressions and histopathologic diagnoses made by clinicians and artificial intelligence tools for odontogenic keratocyst (OKC) and Odontogenic tumours (OT) in a New Zealand population from 2008 to 2023. METHODS: Histopathological records from the Oral Pathology Centre, University of Otago (2008-2023) were examined to identify OKCs and OT. Specimen referral details, histopathologic reports, and clinician differential diagnoses, as well as those provided by ORAD and Chat-GPT4, were documented. Data were analyzed using SPSS, and concordance between provisional and histopathologic diagnoses was ascertained. RESULTS: Of the 34,225 biopsies, 302 and 321 samples were identified as OTs and OKCs. Concordance rates were 43.2% for clinicians, 45.6% for ORAD, and 41.4% for Chat-GPT4. Corresponding Kappa value against histological diagnosis were 0.23, 0.13 and 0.14. Surgeons achieved a higher concordance rate (47.7%) compared to non-surgeons (29.82%). Odds ratio of having concordant diagnosis using Chat-GPT4 and ORAD were between 1.4 and 2.8 (p < 0.05). ROC-AUC and PR-AUC were similar between the groups (Clinician 0.62/0.42, ORAD 0.58/0.28, Char-GPT4 0.63/0.37) for ameloblastoma and for OKC (Clinician 0.64/0.78, ORAD 0.66/0.77, Char-GPT4 0.60/0.71). CONCLUSION: Clinicians with surgical training achieved higher concordance rate when it comes to OT and OKC. Chat-GPT4 and Bayesian approach (ORAD) have shown potential in enhancing diagnostic capabilities.

In vivo healing of low temperature deproteinized bovine bone xenograft in a rabbit cranial model.

The physicochemical properties of grafting materials affect the quality of the osteointegration, resorption rate, and the new bone (NB) formation. This study assessed the physicochemical properties and integration of a low temperature deproteinized bovine bone xenograft (BBX), referred to as optimized MoaBone® (OMB). This novel BBX was physiochemically characterized both pre and post chemical bleaching and sterilization by gamma irradiation. OMB was compared to two commercial BBX; Bio-Oss® (BO) and MoaBone® (MB) using a rabbit cranial model. Residual graft and NB were quantified using histology and micro-computed tomography. Results showed that chemical treatment and gamma irradiation had limited effect on the surface texture. A significant decrease in the collagen content was detected post chemical treatment and in the carbonate content post gamma irradiation. There was no evidence of inflammatory infiltrate, necrosis, or connective tissue encapsulation, and a significant increase of NB in all grafted sites as compared to untreated defects could be observed. However, there was no statistically significant difference between the grafted sites. We conclude that chemical treatment and terminal sterilization strongly impact the final graft's properties. OMB graft showed equivalence with BO for in vivo bone formation and potentially results in lower levels of graft retention.

Diagnosis of oral potentially malignant disorders: Overview and experience in Oceania.

The diagnosis and management of oral potentially malignant disorders (OPMD) should be the same the world over, but there are important nuances in incidence, aetiological factors, and management opportunities that may lead to differences based on ethnogeography. In this review, we update and discuss current international trends in the classification and diagnosis of OPMD with reference to our experience in various regions in Oceania. Oceania includes the islands of Australia, Melanesia (including Papua New Guinea, Fiji, Solomon Islands, Micronesia and Polynesia (including New Zealand, Samoa, Tonga) and hence has diverse populations with very different cultures and a range from well-resourced high-population density cities to remote villages.

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.

Immunohistochemistry and Immunofluorescence.

Immunohistochemistry (IHC) is one of the most widely used protein detection techniques. The principle of this technique is based on the binding of a specific antibody to a matching specific antigen in tissue. The bound antigen-antibody complex then is visualized using a range of detection techniques. IHC uses a number of different enzymatic labels, such as peroxidase and alkaline phosphatase, for the detection of the antigens of interest whereas immunofluorescence (IF) uses a fluorescent signal. In this chapter, IHC will be described using the peroxidase label. Both IHC and IF can be used on formalin-fixed paraffin-embedded (FFPE) or appropriately processed fresh tissues. IHC/IF can be multiplexed to detect more than one antigen at a time, or may be sequentially stained to detect multiple targets. These techniques are routinely used in diagnostic pathology laboratories, not just for diagnostic purposes but many biomarkers are used for patient staging, treatment allocation, and prognostication. Immunofluorescence is routinely used for the detection of antibodies and antigens in freshly biopsied tissues, particularly for immune-mediated and vesiculobullous lesions. In this chapter, the principles of IHC are reviewed followed by examples of IHC and IF staining using readily available antibodies. Steps and processes involved in IHC/IF double staining are also described.

Comparing Two Methods for the Isolation of Exosomes.

Exosomes are membrane-bound nanovesicles released by cells into their extracellular environment. They carry different types of RNA including mRNA which may be useful in the diagnosis of various diseases. Exosome isolation has been a challenge because of their small size; therefore, two exosome isolation methods were compared in this study. The Exoquick-TC PLUS™ exosome isolation kit (kit) was compared with the classic ultracentrifugation (UC) method for exosome isolation. In samples obtained using both methods, cryo-electron microscopy showed round or slightly elongated vesicles with diameters ranging from 50 to 150 nm and delimited by a bilayered membrane. Dynamic light scattering resulted in multiple peaks for kit exosomes, whereas a single peak was observed for UC exosomes. Significantly, more total RNA was present in UC exosomes in contrast to kit exosomes (P < 0.0001). This was reflected in subsequent mRNA analysis using qPCR, where UC exosomes had lower Ct values compared to kit exosomes. In conclusion, exosome characterization revealed the presence of exosomes in both UC and the kit samples. The kit samples presented additional peaks from DLS which might be due to impurities. Overall, due to a higher total RNA and mRNA content, UC is a better option for subsequent mRNA analysis; nevertheless, the kit can still be used if an ultracentrifuge is not available as four out of the five genes selected were detected and quantified using the kit.

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.

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.

Malignant transformation in oral lichen planus and lichenoid lesions: a 14-year longitudinal retrospective cohort study of 829 patients in New Zealand.

OBJECTIVE: The aim of this study was to identify the rate of malignant transformation in a longitudinal cohort of patients with oral lichen planus and oral lichenoid lesion (OLP/OLL) and to assess the associations between clinicopathologic aspects and malignant transformation. STUDY DESIGN: Data were taken from the records of 829 patients histologically diagnosed with OLP/OLL in the years 2005 to 2018. RESULTS: Of the study patients, 548 (66.1%) were females and 281 (33.9%) were males. The average age at diagnosis was 57.3 years. The hyperplastic type was the most frequent (58.5%). Most patients had multiple sites of involvement, with the buccal mucosa being the most frequent site of biopsy. Oral epithelial dysplasia developed in 5 (0.6%) patients with a previous histologic diagnosis of OLP/OLL and developed oral squamous cell carcinoma (OSCC) in 23 patients (2.8%) during the follow-up period. The atrophic/ulcerative forms are 25.8 times more likely to progress to OSCC compared with the hyperplastic types (hazard ratio [HR] 25.8; P < .05). The HR increases by 5% with every year of age (HR 1.05; 95% confidence interval; P < .05). CONCLUSIONS: In our study, oral epithelial dysplasia developed in less than 1% of patients with OLP/OLL, and OSCC in 2.8%during the follow-up period. The atrophic/ulcerative forms are 25.8 times more likely to progress to OSCC compared with the hyperplastic types. The HR increases by 5% with every year of age.

An in-vitro mechanical strain three-dimensional culture model: periodontal ligament cell viability, apoptosis, and endoplasmic reticulum stress response.

To develop a model to investigate a potential relationship between mechanical strain, cell responses, and endoplasmic reticulum stress in periodontal ligament (PDL) cells, primary PDL cell cultures were obtained from extracted premolars. Cells were cultured in hydrogel and subjected to 24 h of static mechanical strain, resulting in 18% dimensional substrate elongation. Cell viability, caspase-3/7 activity, and mRNA levels for 28 genes, including unfolded protein response (UPR)-related and mechanically responsive genes, serving as positive controls for stress induction, were examined. Compared with unstrained cultures, no difference in caspase activity was observed; however, viability responses differed between cell lines. Multiple UPR-related genes were differentially upregulated, with marginal statistical significance, including cAMP responsive element binding protein 3 like 3 (CREB3L3) (mean fold-regulation = 1.91), an adenosine monophosphate-dependent transcription factor with roles in UPR activation and the acute inflammatory response; and the pro-apoptotic UPR gene, endoplasmic reticulum to nucleus signaling 2 (ERN2) (mean fold-regulation = 4.01). The observed effect on cell viability following strain with no change in caspase activity suggests that reduction in viability may be mediated via caspase-3/7-independent mechanisms. Three-dimensional mechanical strain PDL cell culture models offer a method to study the role of endoplasmic reticulum stress and UPR, and provide a framework and potential UPR targets for future investigations.

The relative frequency of paediatric oral and maxillofacial pathology in New Zealand: A 10-year review of a national specialist centre.

BACKGROUND: There has been no previous report of the prevalence of paediatric oral and maxillofacial pathology in a New Zealand oral pathology diagnostic service. AIM: The aim of this study was to review cases of paediatric oral pathology to determine relative frequencies of oral lesions in this age group. DESIGN: Paediatric oral pathology cases (≤15 years of age) received between 2007 and 2016 were retrieved from the electronic database of the Oral Pathology Centre, University of Otago. Data collected included diagnoses (categorised into 12 groups), age at diagnosis, and gender. The prevalence of each diagnosis was calculated in terms of percentage of all diagnoses made. Male-to-female ratio and mean age at diagnosis were also determined. RESULTS: A total of 1139 paediatric cases were identified representing 5.2% of all cases. The most common diagnostic group was salivary gland pathology (25.4%), followed by dental (24.8%) pathology. The most prevalent lesion was mucocoele (23%), followed by dental follicle (14.1%). Malignancies were rare with only two cases identified. CONCLUSION: The findings provide an insight into the prevalence of paediatric oral pathology for clinicians. Mucocoele was the most common diagnosis made, suggesting a high prevalence of soft tissue injury as a main presenting concern warranting diagnosis and management through biopsy.

Tunicamycin-induced endoplasmic reticulum stress up-regulates tumour-promoting cytokines in oral squamous cell carcinoma.

AIMS: Signal transducer and activator of transcription (STAT)-3 lies at the convergence point of key pathways involved in many malignancies including oral squamous cell carcinoma (OSCC). Endoplasmic reticulum stress (ERS) and the unfolded protein response have been shown to be involved in the pathogenesis and progression of different cancers by influencing key cellular processes such as apoptosis. We investigated the differential expression of STAT3 pathway-related genes and proteins under ERS in OSCC. METHODS: Three normal oral keratinocyte (NOK) and three OSCC cell lines were subjected to tunicamycin to induce ERS for 24 h or to the vehicle medium as control. A pathway-focussed array was used to analyse the modulation of STAT3 pathway gene expression under ERS using qPCR. The expression of key regulated proteins was investigated in the cell lines using immunocytochemistry and in 76 OSCC and 9 normal oral mucosa (NOM) tissue samples using tissue microarray technology and immunohistochemistry. RESULTS: ERS resulted in up-regulation of interleukin-6 receptor (IL6R) gene in NOK cell lines (p = 0.001) and IL5 (p = 0.005) and IL22 (p = 0.024) in OSCC cell lines. Greater STAT3 (p = 0.019) and leukaemia inhibitory factor receptor (p = 0.042) protein expression was observed in treated than untreated NOK cell lines. CONCLUSIONS: The gene and protein regulation patterns show that ERS plays a role in modifying the tumour microenvironment in OSCC by up-regulating tumour-promoting cytokines.

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.

Tumor protein 53 mutations are enriched in diffuse large B-cell lymphoma with irregular CD19 marker expression.

Accumulating evidence suggests tumor protein 53 (p53) promotes correct cellular differentiation. Thus, mutant TP53 may be more frequent in tumors with irregular differentiation. This study investigated whether TP53 mutations were more frequent in diffuse large B cell lymphoma (DLBCL) that lacked the B cell lineage marker CD19. Sixteen CD19 negative and 78 CD19 positive DLBCL were sequenced for TP53 mutations. Twenty nine tumors had TP53 mutations and were associated with poorer survival. Mutant TP53 was more frequent in CD19 negative lymphomas (81% versus 21%, p < 0.0001). Analysis of other B cell markers revealed a lack of paired box 5 (PAX5) in CD19 positive lymphomas with mutant TP53 (50%), which was more frequent compared to tumors with wild-type TP53 (15%, p = 0.002). In summary, DLBCL lacking CD19 or PAX5 expression were more likely to have mutant TP53, suggesting irregular B cell marker phenotypes are associated with TP53 mutation.

The nexus between periodontics and oral pathology.

A wide variety of lesions may arise from the oral mucosa, fibrous connective tissue, bone and cementum of the periodontium. The commonest pathology occurs as a result of bacterial infection and is very well known to dentists and periodontists, but rarer conditions present as gingival pathology. The pathogenesis of these conditions ranges from genetic to traumatic to immunological to neoplastic, and includes benign, malignant and metastatic lesions. This paper outlines some of these conditions and describes how the periodontist and oral pathologist can work together using a framework, and how with careful consideration of the clinical features and the use of appropriate special tests, including obtaining an adequate tissue specimen, a timely and accurate diagnosis can be obtained.

Unfolded protein response-related gene regulation in inflamed periodontal tissues with and without Russell bodies.

OBJECTIVE: To examine the expression of unfolded protein response (UPR) genes, a set of genes that are activated to assist in protein trafficking and cellular homeostasis when endoplasmic reticulum (ER) stress occurs, in inflamed and uninflamed periodontal tissues, with or without Russell bodies (RB). RB are a histologically apparent extension of the ER that represents an accumulation of abnormal proteins that cannot be secreted or degraded and may serve as a marker of ER stress. DESIGN: Periodontal tissue specimens were collected and categorised histologically based on the presence of inflammation and the quantity of RB. The differential regulation of 84 UPR-related genes was examined by qRT(2)-PCR. RESULTS: UPR genes related to the inositol-requiring ER-to-nucleus signal kinase (IRE)-1 pathway, molecular chaperones and ER quality control were up-regulated in RB(+) tissues compared with RB(-) tissues, irrespective of inflammation. Inflamed periodontal tissues showed a marked down-regulation of heat shock protein (HSP)-70 family members. CONCLUSION: The presence of RB in inflamed periodontal tissues correlated with the expression of a unique set of ER stress-related genes and therefore may serve as a marker of UPR response in periodontal inflammation. Inflamed periodontal tissues showed a marked down-regulation of UPR genes, in particular HSP70. This may be contributory to disease progression in periodontal disease.

Oral mycosis fungoides: report with immune profile.

Mycosis fungoides (MF) is a cutaneous T-cell lymphoma that uncommonly involves the oral mucosa. Oral MF is an indication of systemic progression and is often associated with an unfavorable outcome. Any oral mucosal site may be affected. This report describes a case of MF involving the hard palate of a 64-year-old woman with confirmed skin MF. The histology showed intra- and subepithelial atypical lymphocytes. Immunohistochemistry on the tissue sections showed that the CD4:CD8 ratio was high (5.8:1) and the CD8:CD3 ratio was low (0.16:1). FoxP3(+) (forkhead box P3-positive) regulatory T cells were conspicuous within the infiltrate, but few interleukin-17 cells were observed. This report is the first to describe a detailed immune profile in oral MF.