The impact of dental Medicaid reform on dental care provider activity and market penetration of dental support organizations.

BACKGROUND: Medicaid state dental programs have experienced changes related to provider practice settings with the increased growth of dental support organizations (DSOs). The authors conducted this study to assess the impact of state Medicaid reform on the dental practice environment by examining provider activity and practice setting. METHODS: This was a retrospective cohort study of more than 13 million dental claims in the Virginia Medicaid program. It included children and dental care providers in the Virginia dental Medicaid program at some time during a 9-year period (fiscal years 2003-2011). The independent variable was the provider practice setting: private practice, DSO, and safety-net practice. The outcomes included annual measures of claims, patients, and payments per provider. The outcomes were examined over 3 phases of the study period: prereform (2003-2005), implementation phase (2006-2008), and postreform maturation (2009-2011). RESULTS: Provider activity increased after dental program reform, with private-practice providers delivering most of the dental care in the Medicaid program. There was a significant penetration of DSO providers in number of providers, claims per provider, and patients per provider (P < .001). Regression results found that providers in DSO settings had an increased number of patients and claims compared with private-practice providers. CONCLUSIONS: Medicaid reform has resulted in a significant increase in provider participation and growth of DSO-affiliated providers. PRACTICAL IMPLICATIONS: Areas of the state with more dense population had a higher penetrance of dentists practicing in DSO settings providing dental services to children enrolled in Medicaid.

Morphology and projections of neurobiotin-labeled nucleus tractus solitarii neurons recorded in vitro.

The suitability of the anterograde tracer neurobiotin to provide information about the morphology and projections of extracellularly or intracellularly recorded medial nucleus tractus solitarii (nTS) neurons was evaluated in horizontally oriented rat dorsal medulla in vitro slices. After responsiveness to angiotensin (Ang) II, substance P (SP), and L-glutamate was evaluated, neurons were labeled by electrophoresis of neurobiotin at the recording site. Extracellular application (2 microA for 2 min) produced discrete injection sites (40-70 microns) with a small group of labeled neurons. Ejections into the solitary tract documented that the tracer was not taken up by axons traversing the injection site. Neuronal perikarya, primary and secondary dendrites, and axons exhibited a dense Golgi-like appearance, with well-defined dendritic spines and axonal varicosities. Dendritic or axonal processes could be followed for more than 1 mm from the cell soma in a 50 microns thick section, documenting the horizontal architecture of the medial nTS. Intracellular electrophoresis filled the soma, primary and secondary dendrites, and axons of neurons characterized for responsiveness to peptides, L-glutamate and solitary tract stimulation. The location within the nTS and axonal projections of neurons responsive to Ang II and SP appeared to differ from those of cells responsive to Ang II and L-glutamate. Thus, either extracellular or intracellular application of neurobiotin in the in vitro slice can reveal differences in axonal or dendritic targets of neuronal subgroups responsive to different neurotransmitters or peptides and provide evidence for the likely autonomic significance of the neurons.