ABSTRACT
OBJECTIVES: Extraction of mandibular posterior teeth followed by immediate implant placement is considered as an optimal technique of immediate prosthetic rehabilitation. The analysis of alveolar bone dimensions with Cone Beam Computerized Tomography prior to implant placement is a prime determinant in treatment planning. Hence this preliminary study was conducted to analyze the alveolar bone dimensions in dentate mandibular posterior teeth to evaluate the available bone which can be utilized for immediate implant placements. MATERIALS AND METHODS: Retrospective data of 200 cases of full volume CBCT was procured from Riyadh Elm University (REU) database and reviewed for eligibility. Atotal of 10 cases were included in the study. Scans were assessed for thickness of buccal and lingual walls at 4mm below the CEJ (MP1) and at midroot level (MP2). Alveolar width was assessed at most coronal point on alveolar bone (BW1) and at superior border of mandibular canal (BW2). The height was be calculated by measuring the vertical distance between BW1 and BW2. Data was tabulated and statistically analyzed using unpaired t-test. RESULTS: The results of our study indicates that dimensions of buccal and lingual bone walls of all teeth at MP1 and MP2 in PM1, PM2 and M1 were statistically significant. Also only the 1st premolar (PM1) showed statistical significance with regard to dimensions at BW1 and BW2. CONCLUSION: The present study highlights the need for further studies with larger samples which can impact the immediate implant success rates in mandibular posterior teeth
ABSTRACT
Sonic Hedgehog gene (SHH) plays a vital role in embryogenesis through its secreted protein sonic hedgehog protein (Shh). During embryogenesis, Shh acts as a morphogen controlling proximal and distant signaling in the specific development of tissue lineages, patterning, regulation of cell proliferation and suppression of tissue apoptosis. Shh also exerts its role in odontogenesis by determining the site of tooth bud formation, in tooth morphogenesis and root formation. The difference in the specific development of a region by Shh can be explained by its [a] 'Spatial gradient [b] the 'form' [c] Concentration gradient and [d] Temporal gradient. Shh signaling pathway has an extracellular and an intracellular component. A disruption of Shh pathway contributes to tumorigenesis of several cell types including those arising from odontogenic structures. This article reviews Shh from its formation in embryonic stages, its role in development and odontogenesis, to its reactivation in tumorigenesis and in specific to odontogenic pathologies.