Analysis of collagen fibers in keratocystic odontogenic tumor and ameloblastoma: A polarizing microscopic study

Introduction: Collagen forms an integral part of connective tissue and maintains its structural integrity. It has natural birefringence which is attributed to the arrangement of its fibers and is enhanced by special stains such as picrosirius red through polarizing microscopy. The polarization colors differ according to the fiber thickness and pattern of arrangement which in turn related to aggressiveness. Hence, the present study was conducted to evaluate collagen fibers in keratocystic odontogenic tumor (KCOT) and ameloblastoma using polarizing microscopy. Aim: This study aims to compare and correlate different types and patterns of collagen fibers in KCOT and ameloblastoma using picrosirius red stain under polarizing microscopy to delineate their aggressiveness. Materials and Methods: The color, thickness, and orientation of collagen fibers in the KCOTs (n = 15) and ameloblastomas (n = 15) were studied histochemically by staining the sections with picrosirius red and examined under polarizing microscope using image analyzer software. Results: When collagen fiber bundles in KCOT and ameloblastoma were compared, significant difference was noted between yellowish-orange collagen fiber bundles, but no significant difference was observed between greenish-yellow and orange-red collagen bundles. With respect to orientation and organization, the results are statistically significant (P < 0.05). Conclusion: The connective tissue stroma of KCOT could be regarded not just as a structural support but as a functional part of the lesion. In KCOT, the thin, parallel, and loosely arranged greenish-yellow collagen fibers may be attributed to its high recurrence rate and biological aggressiveness.

Evaluation of Fibrotic Changes in OSMF:A Retrospective Study Using Special Stains and Polarizing Microscopy

Background: Oral submucous fibrosis (OSMF), a potentially malignant oral disorder has the highest rate of malignant transformation of about 7-13%. The connective tissue changes that occur in this disease are characteristic and are stained with special stains. Objective: The study was done to compare common and special stains under light microscopy and polarizing microscopy to evaluate the levels of fibrosis in oral submucous fibrosis and assess the type of collagen present in the stromal area. Materials and Methods: Fifty tissue blocks were selected from the archives and were prepared and stained with H&E, Masson's trichrome, Van Gieson and Picrosirius red and studied under light microscope and polarizing microscope respectively. Results: H and E stained slides were useful in diagnosing the lesion but was not able to highlight the level of fibrosis. Masson's trichrome and Van Gieson stained slides showed the depth of the lesion which extended even to the deeper muscle layer. The type of collagen present was definitively seen by the birefringence in polarizing microscopic study. Interobserver variation was less and all the values regarding the effectiveness of the special stains in detecting the level of fibrosis were statistically significant. Conclusion: Special stains can be used routinely in laboratories to demonstrate connective tissue lesions especially in cases of OSMF. Depth of the lesion and the area of involvement help in treatment planning to be delivered. Large scale studies with more categories and inclusion criteria are required along with the special stains to assess the other alterations in OSMF

Demineralization adjacent to orthodontic brackets with fluoride releasing and conventional bonding agents.

Background: Enamel demineralization is an event which is always an integral part of fixed orthodontic treatment due to which fluoride releasing bonding agents are considered to be the most effective but have lower bond strength. Thus, this in vitro study has compared the degree of demineralization and bond strength of conventional and fluoridated bonding agents. Materials and Methods: One hundred and five extracted human premolars divided into Group I evaluated to study demineralization and Group II to evaluate bond strength. Group I was subgrouped into (A, B, C, and D and Group II was subgrouped into A, B, and C (n = 15 in each subgroup). All samples were bonded with metal brackets using Transbond PlusTM, Discover LC orthodontic adhesiveTM, and Transbond XTTM; the first two being fluoride releasing and the third being a conventional bonding composite. Group I samples were followed by sectioning and studied for mean depth of demineralization at the margins of the brackets using polarized microscopy. Group II samples were evaluated only for shear bond strength. Statistical analysis was done using ANOVA and Tukey’s multiple comparison tests. Observation and Results: The mean depth of enamel demineralization and standard deviation was compared between subgroups A and C and B and C and the P value obtained was 0.02 in each group, suggestive of a considerably lesser degree of demineralization in fluoride releasing composites compared to conventional composite. Similarly, when shear bond strength was compared between subgroups A and C and B and C the P value obtained was 0.04 and 0.00, respectively. Thus, the shear bond strength of the fluoride releasing composites was lesser than that of the conventional composite but well within the clinically acceptable range. Conclusion: Fluoride releasing composites can be used to avoid demineralization around the brackets.

Stromal characterization and comparison of odontogenic cysts and odontogenic tumors using picrosirius red stain and polarizing microscopy: A retrospective and histochemical study.

INTRODUCTION: Odontogenic lesions represent a range of conditions, the features of which probably depend on the stage of induction towards tooth formation reached prior to neoplastic or hamartomatous proliferation. It has been also suggested that inductive changes may allow progression from one type of odontogenic tumor to another. The epithelium also plays an important role in the pathogenesis of these lesions; even stroma is likely to play an equally important role in the pathogenesis and biological behavior. So, this study was performed to investigate, compare, and correlate different types of collagen fibers in odontogenic cysts and odontogenic tumors. MATERIALS AND METHODS: Thirty each pre‑diagnosed odontogenic cysts and tumors were histochemically analyzed using a special stain (Picrosirius red stain) and polarizing microscopy. RESULTS: Seven cases (99%) of inflammatory cysts exhibited predominantly greenish‑yellow birefringence indicating procollagen, intermediate, or pathologic collagen fibers suggestive of loosely packed collagen fibers. Predominant yellowish‑orange birefringence exhibited by 21 cases (99%) of developmental cysts was comparable to the yellowish‑orange and orangish‑red to red birefringence exhibited by odontogenic tumors suggesting tightly packed fibers. CONCLUSIONS: The Picrosirius red stain in conjunction with polarizing microscopy serves as a specific and sensitive tool in characterizing collagen fibers in odontogenic cysts and odontogenic tumor.

Stromal differences in odontogenic cysts of a common histopathogenesis but with different biological behavior: A study with picrosirius red and polarizing microscopy.

Objectives: The present study was undertaken to detect and compare the pattern of collagen fibers in odontogenic cysts and also to find out if this methodology could be used to predict the aggressive nature of odontogenic cysts by comparing with the odontogenic tumors. Materials and Methods: The collagen in the wall of 11 odontogenic keratocysts, 14 dentigerous cysts and 14 radicular cysts was studied histochemically by staining sections with picrosirius red and examining under polarizing microscope. This was compared to 10 cases of odontogenic tumors using Z test of proportion at 1% and 5%. Results: In dentigerous cysts, odontogenic keratocysts and odontogenic tumors, the predominant color of collagen fibers birefringence was found to be orangish red, whereas in radicular cysts the collagen fiber was of green color. Conclusions: Similar birefringence pattern of collagen fibers between dentigerous cysts, odontogenic keratocysts and odontogenic tumors may indicate that these lesions have a common histogenesis with a broad spectrum of biological behavior and belong to the same group, i.e., are developmental in origin. Different patterns of radicular cysts suggest different biological behavior and a positive role of inflammation on polarization color of collagen fibers.

Mineralized components and their interpretation in the histogenesis of peripheral ossifying fibroma.

Background: Peripheral ossifying fibroma (POF) is a lesion of gingival tissue that predominantly affects women and is usually located in maxilla, anterior to molars. The definitive diagnosis is established by histopathological examination, which reveals the presence of cellular connective tissue with focal calcifications. Objective: This study hypothesizes the histogenesis of POF by analyzing the diverse spectrum of mineralized components with a polarizing microscope. Materials and Methods: A retrospective study was undertaken which involved a detailed review of clinical, radiographic and histopathological features of 22 cases of POF, retrieved from departmental archives. These cases were subsequently stained with a histochemical stain (van Gieson) and observed under a polarizing microscope. Results: The study revealed that the most common age of occurrence was in second and third decades with a strong female predilection (73%), Interdental papilla of the maxillary anterior region was the most commonly afflicted site. About 90% cases showed no radiographic features.Histopathological examination showed that 73% cases consisted of a fibrocellular connective tissue stroma surrounding the mineralized masses. 50% mineralized masses comprised of woven bone, 18% showed combination of lamellar bone and cellular cementum, 18% showed only cementum (cellular and acellular), and remaining 13.6% exhibited a mixture of woven and lamellar bone under polarizing microscope. Conclusion: The study supports the theory that POF develops from cells of periodontal ligament (PDL)/periosteum as undifferentiated mesenchymal cells having an inherent proliferative potential to form bone or cementum, whose nature can be confirmed by polarizing microscope.

Comparative study of clinicofunctional staging of oral submucous fibrosis with qualitative analysis of collagen fibers under polarizing microscopy.

Objective : The aim of the study was to assess the severity of the disease in oral submucous fibrosis (OSF), correlate the clinical, functional staging with histopathological staging, and analyze collagen distribution in different stages of OSF using the picrosirius red stain under polarizing microscopy. Materials and Methods : The study included randomly incorporated 50 subjects, of whom 40 were patients with OSF, and 10 were in the control group. Clinical, functional staging in OSF cases was done depending upon definite criteria. A histopathological study was conducted using the hematoxylin and eosin stain and picrosirius red stain. Collagen fibers were analyzed for thickness and polarizing colors. Furthermore, clinical, functional, and histopathological stages were compared. Statistical Analysis : Descriptive data which included mean, SD, and percentages were calculated for each group. Categorical data were analyzed by the chi-square test. Multiple group comparisons were made by one-way ANOVA followed by Student's t-test for pairwise comparisons. For all tests, a P-value of 0.05 or less was considered for statistical significance. Results : As the severity of the disease increased, clinically, there was definite progression in subjective and objective symptoms. Polarized microscopic, examination revealed, there was a gradual decrease in the green-greenish yellow color of the fibers and a shift to orange red-red color with increase in severity of the disease. Thereby, it appeared that the tight packing of collagen fibers in OSF progressively increased as the disease progressed from early to advanced stages. We observed that the comparison of functional staging with histopathological staging was a more reliable indicator of the severity of the disease. Conclusion : In the present study, we observed that mouth opening was restricted with advancing stages of OSF. The investigation also points to the importance of assessing the cases of OSF, especially with regard to functional and histological staging in planning the treatment.

The effect of lactic acid concentration and ph of lactic acid buffer solutions on enamel remineralization / 대한치과보존학회지

There are considerable in vitro and in vivo evidences for remineralization and demineralization occurring simultaneously in incipient enamel caries. In order to "heal"the incipient dental caries, many experiments have been carried out to determine the optimal conditions for remineralization. It was shown that remineralization is affected by different pH, lactic acid concentrations, chemical composition of the enamel, fluoride concentrations, etc. Eighty specimens from sound permanent teeth without demineralization or cracks, 0.15 mm in thickness, were immersed in lactic acid buffered demineralization solutions for 3 days. Dental caries with a surface zone and subsurface lesion were artificially produced. Groups of 10 specimens were immersed for 10 or 12 days in lactic acid buffered remineralization solutions consisting of pH 4.3 or pH 6.0, and 100, 50, 25, or 10 mM lactic acid. After demineralization and remineralization, images were taken by polarizing microscopy (x100) and micro-computed tomography. The results were obtained by observing images of the specimens and the density of the caries lesions was determined. 1. As the lactic acid concentration of the remineralization solutions with pH 4.3 was higher, the surface zone of the carious enamel increased and an isotropic zone of the subsurface lesion was found. However, the total decalcification depth increased at the same time. 2. In the remineralization solutions with pH 6.0, only the surface zone increased slightly but there was no significant change in the total decalcification depth and subsurface zone. In the lactic acid buffer solutions with the lower pH and higher lactic acid concentration, there were dynamic changes at the deep area of the dental carious lesion.