Painting the Portrait of Fibro-osseous Lesions: An In-vitro Study on Staining Duel of Modified Gallego versus Hematoxylin and Eosin (H&E) Staining

Introduction: Oral cavity tumours involve a mix of soft and hard tissues, with varying levels of calcification posing diagnostic challenges. Detecting the presence or absence of calcification in connective tissue tumours, whether central or peripheral, benign or malignant, is particularly challenging. Routine stains like Haematoxylin and Eosin (H&E) fail to adequately reveal the specific features of these hard tissues. Alternative histochemical staining procedures, such as Modified Gallego’s Stain (MGS), offer better visualisation of the hard-tissue components in the decalcified sections. Aim: To evaluate and compare the staining efficacy of H&E and MGS to differentiate bone and cemental tissue in histopathologically diagnosed oral and maxillofacial pathologies. Materials and Methods: An in-vitro histochemical retrospective study was conducted at the Department of Oral and Maxillofacial Pathology at MGM Dental College, Navi Mumbai, Maharashtra, India, from October 2018 to January 2021. A total sample size of 60 was chosen using a convenient sampling technique, comprising decalcified tissue sections of normal teeth with periapical bone (n=10), normal bone (n=10) and normal teeth (n=10) as the control group. The study group included pathologies of bone and cemental tissues (cemento-ossifying fibroma, odontome, focal cemento-osseous dysplasia) (n=10), pathological bony tissue (juvenile ossifying fibroma, fibrous dysplasia, aneurysmal bone cyst, peripheral ossifying fibroma, juxtacortical osteosarcoma) (n=10) and pathological cemental tissue (odontome, cementoblastoma) (n=10). Serial sections from each sample were taken. One section was stained with H&E stain and another with MGS. Stained sections were viewed using routine light microscopy and evaluated under 40X, 100X and 400X magnification. Histochemical evaluation was performed for the intensity of stain and its tissue differentiation capability for osteoid, immature bone, mature bone, cementoid and cementum. All statistical analysis were performed using the Statistical Package for Social Sciences (SPSS v 26.0, IBM). The data obtained were presented using descriptive statistics. The Chi-square test was used and statistical significance was set at a p-value of less than or equal to 0.05. Results: The MGS had better efficacy than routine H&E stain in differentiating bone and cemental tissues of decalcified tissue sections from various oral and maxillofacial pathologies. A comparison of the H&E and MGS between various study and control groups showed statistically significant results (p<0.05) in differentiation and intensity. Conclusion: The MGS is a better histochemical stain than the routine H&E stain, with increased differentiation and clarity in identifying bone and cemental tissues; hence, it can be considered a reliable method to differentiate pathological tissues.