📝 “What are the SNA & SNB Values in Determining Prognathism vs. Retrognathism of the Maxilla &Mand?”

8.23.24Quick Review #212 - #surgery #surgeon #doctorgallagher #oralsurgery #oralsurgeon #omfs #dentist #dentistry #dental #mandible #maxilla #prognathic #retrognathic The SNA and SNB angles in cephalometric analysis assess the anteroposterior positions of the maxilla and mandible relative to the cranial base.• Sella (S): the central point of the Sella turcica, a saddle-shaped depression in the sphenoid bone at the base of the skull.• Nasion (N): the point located at the intersection of the frontal bone and the nasal bones, at the bridge of the nose. It represents the most anterior point of the frontonasal suture in the midsagittal plane.• A Point (A): also known as Subspinale, is the deepest concavity on the anterior surface of the maxilla, located between the anterior nasal spine and the alveolar ridge of the upper central incisors. It represents the most anterior point of the maxillary alveolar process.• B Point (B): also known as Supramentale, is the deepest concavity on the anterior surface of the mandible, located between the infradentale (the tip of the mandibular alveolar process) and the pogonion (the most anterior point on the chin). It represents the most anterior point of the mandibular alveolar process.SNA (Sella-Nasion-A Point):• Normal Range: 82° to 84°• Maxillary Hypoplasia (Retrognathism): SNA • Maxillary Hyperplasia (Prognathism): SNA > 84°SNB (Sella-Nasion-B Point):• Normal Range: 78° to 80°• Mandibular Hypoplasia (Retrognathism): SNB • Mandibular Hyperplasia (Prognathism): SNB > 80°Relation to Determining Prognathism vs. Retrognathism:• Prognathism: A condition where the maxilla or mandible is positioned anteriorly (forward) relative to the cranial base. This is indicated by an SNA > 84° for maxillary prognathism or an SNB > 80° for mandibular prognathism.• Retrognathism: A condition where the maxilla or mandible is positioned posteriorly (backward) relative to the cranial base. This is indicated by an SNA These values are crucial in diagnosing skeletal discrepancies and planning orthodontic or surgical interventions.References:1. Al Zain, T., & Ferguson, D. J. (2012). Cephalometric characterization of an adult Emirati sample with Class I malocclusion. Journal of Orthodontics, 39(1), 61-66.2. Proffit, W. R., Fields, H. W., Sarver, D. M., & Ackerman, J. L. (2018). Contemporary Orthodontics (6th ed.). Elsevier.3. McNamara, J. A. (1984). A method of cephalometric evaluation. American Journal of Orthodontics, 86(6), 449-469.4. Bishara, S. E., & Jacobsen, J. R. (1998). Cephalometric skeletal and dental changes after treatment with the Twin-block appliance. American Journal of Orthodontics and Dentofacial Orthopedics, 113(3), 236-243.5. ChatGPT. 2024.#podcast #podcasts #dentalpodcast #dentalpodcasts #doctorgallagherpodcast #doctorgallagherspodcast #doctor #dentistry #oralsurgery #dental #viral #dentalschool #dentalstudent #omfs #surgeon #doctorlife #dentistlife #residency #oralsurgeon #dentist #doctorgallagher