Bacteria are central to the development of pulp and periradicular disease (PPD). Nevertheless, th... more Bacteria are central to the development of pulp and periradicular disease (PPD). Nevertheless, the relationship between bacteria and inflammatory root resorption (IRR) associated with PPD remains unclear. Toll-like receptors (TLRs) function as one of the host's key receptors for microorganisms. Among the human TLRs that have been identified, TLR2 is considered crucial for recognizing gram-positive bacteria while TLR4 is essential for pro-inflammatory signaling to cell wall components of gram-negative bacteria. Once antigens are recognized, the host immunity leads to various inflammatory responses including resorption of osseous (hard) tissue. Objectives: This study was carried out to assess by immunohistochemistry (IHC) the association of bacterial antigen recognition (TLR2, TLR4 expression), inflammatory cell response (identification of CD3, CD19, CD83 cell types), and hard tissue resorption (RANK/RANKL/OPG system) in PPD associated IRR lesions. Methods: Nine samples of externa...
To describe the patterns of facial fractures presenting to a tertiary referral centre in New Zeal... more To describe the patterns of facial fractures presenting to a tertiary referral centre in New Zealand, and to identify risk indicators for maxillofacial trauma. 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. 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. Presentation of patients with fa...
The aims of this study were to determine the presence and distribution of vascular endothelial gr... more The aims of this study were to determine the presence and distribution of vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor-2 (VEGFR2) in dentigerous cysts compared with normal dental follicles as a control tissue and to evaluate endothelial cells and proliferating cells as indicators of angiogenic activity in these tissues.Twenty specimens histologically diagnosed as dentigerous cysts and 20 dental follicle specimens were included. Immunohistochemistry (IHC) using anti-VEGF and anti-VEGFR2 antibodies stained for the growth factor and its receptor, while anti-CD34 and anti-CD146 antibodies were used to identify endothelial cells. Anti-proliferating cell nuclear antigen (PCNA) antibody detected proliferating cells within the specimens. Slides were examined microscopically and results evaluated using kappa statistics, negative binomial regression and ordinal logistic regression.The mean age for patients with dentigerous cysts was 23 years and they were more common in males. Proteins for VEGF, VEGFR2, PCNA, CD34, and CD146 were expressed in all dentigerous cysts and dental follicles. VEGF and VEGFR2 were expressed on several cell types within the tissues, however there was a significantly greater percentage of positive staining in dentigerous cysts compared with dental follicles (odds ratio = 31.24, p < 0.001). CD34(+), CD146(+), and PCNA(+) cells were observed in both dentigerous cysts and dental follicles but for all markers there were significantly more positive cells in dentigerous cysts (p < 0.001); this was especially evident in cases associated with inflammation. PCNA was seen in most endothelial cells lining small thin walled blood vessels suggesting endothelial proliferation. There was a high level of intra- and inter-examiner agreement (kappa 0.77 and 0.75, respectively).VEGF and VEGFR2 and angiogenic activity are present in dental follicles and dentigerous cysts and may contribute to local bone resorption for tooth eruption or the development and progression of dentigerous cysts.
Oral lichen planus (OLP) is an immunological disease and while it is understood that the T cell s... more Oral lichen planus (OLP) is an immunological disease and while it is understood that the T cell subsets, FoxP3(+) Tregs and IL17(+) Th17 cells are involved in immune regulation, little is known about their presence in OLP. The aims of this study were to compare the number of cells expressing FoxP3 or IL-17 in OLP with non-specifically inflamed oral mucosa and to determine which cell types expressed FoxP3 and/or IL-17 and their distribution. Immunohistochemistry was used to investigate the presence of FoxP3(+) or IL-17(+) cells in 12 control cases and 17 cases of OLP. These results were analysed quantitatively and qualitatively. Double-labelling immunofluorescence (IF) was used to determine the type of cell expressing FoxP3/IL-17 and these results were analysed qualitatively. OLP displayed significantly more FoxP3(+) cells (mean 79.3 vs. 20.6 cells/defined area, p < 0.0001) and fewer IL-17(+) cells (mean 1.05 vs. 3.30 cells/defined area, p = 0.0003) than non-specific inflammatory ...
The teaching of advanced endodontic courses at the predoctoral level is common, but it can be dif... more 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 r...
To describe the patterns of facial fractures presenting to a tertiary referral centre in New Zeal... more To describe the patterns of facial fractures presenting to a tertiary referral centre in New Zealand, and to identify risk indicators for maxillofacial trauma. 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. 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. Presentation of patients with fa...
To investigate and compare the expression of the pathogen recognition receptors Toll-like recepto... more To investigate and compare the expression of the pathogen recognition receptors Toll-like receptor (TLR) 2 and TLR4, and the hard tissue resorption triad osteoprotegerin (OPG)-receptor activator of nuclear factor kappa-B ligand (RANKL)-receptor activator of nuclear factor kappa-B (RANK) in external inflammatory root resorption of endodontic origin (ER) and external cervical root resorption (ECR) by immunohistochemistry. Formalin-fixed, paraffin-embedded archival specimens collected from teeth that were diagnosed clinically, radiographically and histopathologically with either ER (n = 9) or ECR (n = 9) were processed for immunohistochemistry to investigate and compare levels of TLR2, TLR4, OPG, RANKL, RANK, CD3, CD19 and CD83 expression. The histological features were evaluated via haematoxylin and eosin stain. Taylor&#39;s modification of the Brown and Brenn Gram stain was used for examining the presence and distribution of bacteria. All stained slides were digitally photographed and qualitatively analysed, and F test and unpaired Student&#39;s t-test were used for statistical analysis. Both ER and ECR showed similar immuno-histopathology characteristics of a fibrovascular connective tissue with varying degrees of inflammatory infiltrate consisting of T and B lymphocytes, dendritic cells, polymorphonuclear lymphocytes and plasma cells. Colonies of bacteria were identified in the majority of lesions, and this correlated with the cellular expression of TLR2 and TLR4 in all lesions. Similarly, all lesions showed a significantly higher (P &lt; 0.05) level of cells expressing RANKL than OPG, indicating hard tissue resorption processes where active in the lesions. The immunohistopathology patterns of ECR samples were consistent with the bacteria-driven ER specimens, suggesting bacteria-induced inflammation may be involved in ECR.
Bacteria are central to the development of pulp and periradicular disease (PPD). Nevertheless, th... more Bacteria are central to the development of pulp and periradicular disease (PPD). Nevertheless, the relationship between bacteria and inflammatory root resorption (IRR) associated with PPD remains unclear. Toll-like receptors (TLRs) function as one of the host's key receptors for microorganisms. Among the human TLRs that have been identified, TLR2 is considered crucial for recognizing gram-positive bacteria while TLR4 is essential for pro-inflammatory signaling to cell wall components of gram-negative bacteria. Once antigens are recognized, the host immunity leads to various inflammatory responses including resorption of osseous (hard) tissue. Objectives: This study was carried out to assess by immunohistochemistry (IHC) the association of bacterial antigen recognition (TLR2, TLR4 expression), inflammatory cell response (identification of CD3, CD19, CD83 cell types), and hard tissue resorption (RANK/RANKL/OPG system) in PPD associated IRR lesions. Methods: Nine samples of externa...
To describe the patterns of facial fractures presenting to a tertiary referral centre in New Zeal... more To describe the patterns of facial fractures presenting to a tertiary referral centre in New Zealand, and to identify risk indicators for maxillofacial trauma. 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. 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. Presentation of patients with fa...
The aims of this study were to determine the presence and distribution of vascular endothelial gr... more The aims of this study were to determine the presence and distribution of vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor-2 (VEGFR2) in dentigerous cysts compared with normal dental follicles as a control tissue and to evaluate endothelial cells and proliferating cells as indicators of angiogenic activity in these tissues.Twenty specimens histologically diagnosed as dentigerous cysts and 20 dental follicle specimens were included. Immunohistochemistry (IHC) using anti-VEGF and anti-VEGFR2 antibodies stained for the growth factor and its receptor, while anti-CD34 and anti-CD146 antibodies were used to identify endothelial cells. Anti-proliferating cell nuclear antigen (PCNA) antibody detected proliferating cells within the specimens. Slides were examined microscopically and results evaluated using kappa statistics, negative binomial regression and ordinal logistic regression.The mean age for patients with dentigerous cysts was 23 years and they were more common in males. Proteins for VEGF, VEGFR2, PCNA, CD34, and CD146 were expressed in all dentigerous cysts and dental follicles. VEGF and VEGFR2 were expressed on several cell types within the tissues, however there was a significantly greater percentage of positive staining in dentigerous cysts compared with dental follicles (odds ratio = 31.24, p &amp;amp;amp;amp;amp;amp;amp;lt; 0.001). CD34(+), CD146(+), and PCNA(+) cells were observed in both dentigerous cysts and dental follicles but for all markers there were significantly more positive cells in dentigerous cysts (p &amp;amp;amp;amp;amp;amp;amp;lt; 0.001); this was especially evident in cases associated with inflammation. PCNA was seen in most endothelial cells lining small thin walled blood vessels suggesting endothelial proliferation. There was a high level of intra- and inter-examiner agreement (kappa 0.77 and 0.75, respectively).VEGF and VEGFR2 and angiogenic activity are present in dental follicles and dentigerous cysts and may contribute to local bone resorption for tooth eruption or the development and progression of dentigerous cysts.
Oral lichen planus (OLP) is an immunological disease and while it is understood that the T cell s... more Oral lichen planus (OLP) is an immunological disease and while it is understood that the T cell subsets, FoxP3(+) Tregs and IL17(+) Th17 cells are involved in immune regulation, little is known about their presence in OLP. The aims of this study were to compare the number of cells expressing FoxP3 or IL-17 in OLP with non-specifically inflamed oral mucosa and to determine which cell types expressed FoxP3 and/or IL-17 and their distribution. Immunohistochemistry was used to investigate the presence of FoxP3(+) or IL-17(+) cells in 12 control cases and 17 cases of OLP. These results were analysed quantitatively and qualitatively. Double-labelling immunofluorescence (IF) was used to determine the type of cell expressing FoxP3/IL-17 and these results were analysed qualitatively. OLP displayed significantly more FoxP3(+) cells (mean 79.3 vs. 20.6 cells/defined area, p < 0.0001) and fewer IL-17(+) cells (mean 1.05 vs. 3.30 cells/defined area, p = 0.0003) than non-specific inflammatory ...
The teaching of advanced endodontic courses at the predoctoral level is common, but it can be dif... more 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 r...
To describe the patterns of facial fractures presenting to a tertiary referral centre in New Zeal... more To describe the patterns of facial fractures presenting to a tertiary referral centre in New Zealand, and to identify risk indicators for maxillofacial trauma. 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. 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. Presentation of patients with fa...
To investigate and compare the expression of the pathogen recognition receptors Toll-like recepto... more To investigate and compare the expression of the pathogen recognition receptors Toll-like receptor (TLR) 2 and TLR4, and the hard tissue resorption triad osteoprotegerin (OPG)-receptor activator of nuclear factor kappa-B ligand (RANKL)-receptor activator of nuclear factor kappa-B (RANK) in external inflammatory root resorption of endodontic origin (ER) and external cervical root resorption (ECR) by immunohistochemistry. Formalin-fixed, paraffin-embedded archival specimens collected from teeth that were diagnosed clinically, radiographically and histopathologically with either ER (n = 9) or ECR (n = 9) were processed for immunohistochemistry to investigate and compare levels of TLR2, TLR4, OPG, RANKL, RANK, CD3, CD19 and CD83 expression. The histological features were evaluated via haematoxylin and eosin stain. Taylor&#39;s modification of the Brown and Brenn Gram stain was used for examining the presence and distribution of bacteria. All stained slides were digitally photographed and qualitatively analysed, and F test and unpaired Student&#39;s t-test were used for statistical analysis. Both ER and ECR showed similar immuno-histopathology characteristics of a fibrovascular connective tissue with varying degrees of inflammatory infiltrate consisting of T and B lymphocytes, dendritic cells, polymorphonuclear lymphocytes and plasma cells. Colonies of bacteria were identified in the majority of lesions, and this correlated with the cellular expression of TLR2 and TLR4 in all lesions. Similarly, all lesions showed a significantly higher (P &lt; 0.05) level of cells expressing RANKL than OPG, indicating hard tissue resorption processes where active in the lesions. The immunohistopathology patterns of ECR samples were consistent with the bacteria-driven ER specimens, suggesting bacteria-induced inflammation may be involved in ECR.
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Papers by Lara Friedlander