Steven R. Singer

CBCT-based bone quality assessment: are Hounsfield units applicable?

CBCT is a widely applied imaging modality in dentistry. It enables the visualization of high-contrast structures of the oral region (bone, teeth, air cavities) at a high resolution. CBCT is now commonly used for the assessment of bone quality, primarily for pre-operative implant planning. Traditionally, bone quality parameters and classifications were primarily based on bone density, which could be estimated through the use of Hounsfield units derived from multidetector CT (MDCT) data sets. However, there are crucial differences between MDCT and CBCT, which complicates the use of quantitative gray values (GVs) for the latter. From experimental as well as clinical research, it can be seen that great variability of GVs can exist on CBCT images owing to various reasons that are inherently associated with this technique (i.e. the limited field size, relatively high amount of scattered radiation and limitations of currently applied reconstruction algorithms). Although attempts have been made to correct for GV variability, it can be postulated that the quantitative use of GVs in CBCT should be generally avoided at this time. In addition, recent research and clinical findings have shifted the paradigm of bone quality from a density-based analysis to a structural evaluation of the bone. The ever-improving image quality of CBCT allows it to display trabecular bone patterns, indicating that it may be possible to apply structural analysis methods that are commonly used in micro-CT and histology.

Phosphaturic mesenchymal tumor, mixed connective tissue variant, of the mandible: Report of a case and review of the literature

Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome that results in renal phosphate wasting with hypophosphatemia. In most cases, the underlying cause of TIO is a small mesenchymal neoplasm that is often difficult to detect, resulting in delayed diagnosis. One such neoplasm is the phosphaturic mesenchymal tumor, mixed connective tissue variant (PMTMCT), an unusual entity with unique morphologic and biochemical features. Most of these tumors are found at appendicular sites with only rare cases reported in the jaws. We describe a PMTMCT involving the mandible in a patient with a protracted history of osteomalacia. A review of the current literature is provided with emphasis on the clinical and histologic features, etiopathogenesis, and management of PMTMCT in the setting of TIO.

Oral-facial-digital syndrome type 1: Report of a case

Oral-facial-digital syndrome (OFD) is a collective term describing thirteen distinctive, rare genetic disorders based on inheritance pattern and phenotypic expression. OFD is characterized by malformations of the oral cavity, the maxillofacial region and the arms and legs. Central nervous system anomalies, include intracerebral cysts, agenesis of the corpus callosum, hydrocephalus, cerebral/cerebellar atrophy, and berry aneurysms. Some degree of compromised intellectual ability and speech are present in affected individuals that correlate with the degree of central nervous system involvement. Furthermore, renal involvement in the form of polycystic kidney disease is evident in affected individuals in adulthood. In this article, we present a 37-year-old female patient that presented to the Rutgers School of Dental Medicine with oral-facial-digital syndrome, type 1.