Patient-specific mechanical analysis of PCL periodontal membrane: Modeling and simulation.

This research fills a knowledge gap in bone tissue engineering by examining the mechanical characteristics of scaffolds at bone-tissue interfaces utilizing a cutting-edge technique involving the creation of 3D scaffolds from Polycaprolactone (PCL). The work employs Finite element analysis to measure the scaffolds' maximum principal and Von Mises stresses and strains. CT scans of the Maxilla and Mandible were used to apply load conditions to 3D models of the upper central incisor. In the derived computational model, four different load situations considered were: the masticatory load (70-100 N at 45°), two parafunctional habits (100-130 N) and 500-550 N at the incisal edge, both at 45°), and a trauma case (800-850 N applied perpendicularly from the inwards direction at 90°). The findings revealed that the central tooth region experiences the highest stress concentration, while the Maxilla and Mandible regions show the least stress. These results provide critical insights into the mechanical behavior of scaffolds at bone-tissue interfaces, suggesting a research direction for developing scaffolds that closely mimic real bone characteristics. The results of this study are particularly significant for using bone replacement materials, providing an approach to more effective healing options for bone traumas and degenerative bone disorders.

Expression of p-16, Ki-67 and p-53 markers in dysplastic and malignant lesions of the oral cavity and oropharynx.

BACKGROUND: Understanding the markers for predicting degree of dysplasia and progression to malignancy can help early identification and prompt treatment of patients with oral cancers. In this study, we aim to identify and characterize different tumor suppressor genes such as p-53 and p-16 and proliferation marker Ki-67 in defining stages of dysplasia of oral mucosa and grading of tumor. SETTINGS AND DESIGN: Oral biopsy tissues (for neoplastic lesions) received for histopathological evaluation were included in the study. The sections were processed for H&E staining, and 112 cases were chosen for immunohistochemical study. The data were analyzed by Chi-square and z-tests using software SPSS. RESULTS: We found significant correlation between degree of dysplasia and p-16 immunoexpression with 16.7% of cases showing positivity in oral intraepithelial neoplasia (OIN) I cases as compared to 25% in OIN II and 77.8% in OIN III. Ki-67 immunoexpression correlated significantly with both histological type and grade of tumor with increased expression and intensity seen in malignant cases (66.3%) as compared to benign (10%) and premalignant cases (37%) and higher Ki-67 immunoexpression in poorly differentiated tumors (75%) than well-differentiated tumors (12.2%). Regarding p-53 immunoexpression, positive staining was seen in only malignant cases and premalignant cases. CONCLUSIONS: Ki-67 and p-16 can be useful as a marker of degree of dysplasia and transformation to malignancy. Ki-67 can also serve as a marker of degree of differentiation of tumors. Hence, they can serve as important ancillary markers to analyze the transition to carcinoma, dysplasia and progression of tumor.

Heterogeneous modeling based prosthesis design with porosity and material variation.

The work proposes the development of heterogeneous bio-implants with the aim to minimize stress shielding effect and enhance bone ingrowth. Stress shielding in the implant can be minimized by reducing the overall stiffness of the implant, which is achieved here by varying the material based on stress distribution across the prosthesis. To increase overall stability of the implant by simultaneous enhancing osseointegration and reducing stress shielding, the work proposes the design of heterogeneous prosthesis with graded porosity and material having radial, axial and mixed (simultaneous radial and axial) variations. Static analysis for material variation models and consolidation analysis for graded porosity and material variation models are performed. After comparisons of results among different models, radial variation model was observed to deliver the results.

Skeletal angiomatosis - rare cause of bone destruction: a case report with review of literature.

Classification of skeletal angiomatosis into aggressive and nonaggressive types is on the basis of their clinical behavior and pattern of skeletal involvement (regional and disseminated). Gorham's disease (massive osteolysis) is an aggressive form of skeletal angiomatosis that shows regional involvement, frequently involving the shoulder and hip areas. Cystic angiomatosis is a nonaggressive form of skeletal angiomatosis with multifocal involvement, predominantly affecting the trunk bones. The imaging modalities gave the diagnosis of cystic angiomatosis of humerus showing multicystic lytic areas. The histopathological differential diagnosis was cystic angiomatosis and Gorham's disease, as microscopically both are indistinguishable from each other. Both represent a complex network of dilated thin-walled capillaries growing in the marrow space associated with the destruction of bone and infiltration into the adjacent soft tissues. The case is presented because of its extreme rarity and due to the diagnostic dilemma, whether to label it as Gorham's disease or as cystic angiomatosis. Considering the site involved and its aggressiveness, the diagnosis is in favor of Gorham's vanishing bone disease as cystic angiomatosis is multicentric and nonaggressive, involving mostly vertebrae and skull with multicystic lytic lesions.

Congenital epulis of the newborn: a case report with review of literature.

Congenital epulis, also known as congenital gingival granular cell tumor, is a rare benign intraoral tumor found only in the new born. It can be solitary or multiple and may occur in the mandible, maxilla or tongue and may or may not be associated with other congenital anomalies. The size of the mass varies and if very large may interfere with respiration and feeding at birth, thus necessitating the immediate surgical resection at birth to maintain patency of the airways. Antepartum detection by careful imaging and coordination of multidisciplinary team of maternal-fetal medicine, neonatal-perinatal medicine, anesthesiology and otolaryngology and finally the histopathologists who confirm the diagnosis is essential as the histology differentiates it from other congenital intraoral masses like haemangioma, fibroma, rhabdomyoma, rhabdomyosarcoma, lymphangioma, osteogenic and chondrogenic sarcomas.