IADR Abstract Archives
Neurotrophic Potential of Coronal and Radicular Dentin
Objectives: A broad variety of bioactive molecules are embedded into dentin matrix during odontogenesis. Among these molecules, neurotrophins are involved in orchestrating axonal targeting resulting in the time-controlled innervation of the coronal pulp-dentin complex during root formation. Therefore, we hypothesize that concentrations of known nerotrophins in coronal and radicular dentin differ and have a varied impact on neurite outgrowth.
Methods: Dentin matrix proteins were isolated from matching crowns and roots of extracted healthy third molars. Enzyme-linked immunosorbent assays (ELISA) were performed to quantify the total protein amount as well as the concentrations of common growth factors (TGF-β1, VEGF) and neurotrophins (BDNF, GDNF, NGF, NT3, NT4). A cell-based ELISA for tubulin beta 3 (Tubb3) was conducted with mouse trigeminal neurons exposed to protein extracts from matched crowns and roots. Additionally, neurite outgrowth was visualized by immunofluorescent images and quantified. Lastly, a matrigel implant containing matched protein extracts was used to evaluate neurogenesis in vivo. Data were analyzed by paired t-tests at an α = 0.05 level of significance.
Results: Radicular dentin contained greater concentrations of BDNF, NT3 and NGF, whereas GDNF was reduced compared to coronal dentin. Interestingly, total protein amount and the concentrations of TGF-β1, VEGF and NT4 were indifferent between matched crowns and roots. Generally, neurite outgrowth was promoted by dentin matrix protein extracts both in vitro and in vivo, with greater effect observed with the radicular dentin extracts (P ≤ 0.05).
Conclusions: This study demonstrated, for the first time, the differential distribution of neurotrophic factors in coronal and radicular dentin and their effects on axonal growth and targeting. Thus, extracellular proteins from the dentin matrix could be exploited in clinical regenerative endodontics to promote reinnervation, enhancing tissue regeneration.
Methods: Dentin matrix proteins were isolated from matching crowns and roots of extracted healthy third molars. Enzyme-linked immunosorbent assays (ELISA) were performed to quantify the total protein amount as well as the concentrations of common growth factors (TGF-β1, VEGF) and neurotrophins (BDNF, GDNF, NGF, NT3, NT4). A cell-based ELISA for tubulin beta 3 (Tubb3) was conducted with mouse trigeminal neurons exposed to protein extracts from matched crowns and roots. Additionally, neurite outgrowth was visualized by immunofluorescent images and quantified. Lastly, a matrigel implant containing matched protein extracts was used to evaluate neurogenesis in vivo. Data were analyzed by paired t-tests at an α = 0.05 level of significance.
Results: Radicular dentin contained greater concentrations of BDNF, NT3 and NGF, whereas GDNF was reduced compared to coronal dentin. Interestingly, total protein amount and the concentrations of TGF-β1, VEGF and NT4 were indifferent between matched crowns and roots. Generally, neurite outgrowth was promoted by dentin matrix protein extracts both in vitro and in vivo, with greater effect observed with the radicular dentin extracts (P ≤ 0.05).
Conclusions: This study demonstrated, for the first time, the differential distribution of neurotrophic factors in coronal and radicular dentin and their effects on axonal growth and targeting. Thus, extracellular proteins from the dentin matrix could be exploited in clinical regenerative endodontics to promote reinnervation, enhancing tissue regeneration.