ABSTRACT
Faster and predictable osseointegration is crucial for the success of dental implants, especially in patients with compromised local or systemic conditions. Despite various surface modifications on the commercially available Titanium (Ti) dental implants, the bioactivity of Ti is still low. Thus, to achieve both biological and therapeutic activity on titanium surfaces, surface modification techniques such as titanium nanotubes have been studied as nanotube surfaces can hold therapeutic drugs and molecules. The main aim of the present research work is to study the early osseointegration around the novel Simvastatin drug eluting nanotubular dental implant. In the present research, the titanium nanotubes were fabricated on the screw-shaped dental implant surface and the Simvastatin drug was loaded into the nanotubes using the ultrasonication dip method. In vitro and In vivo studies were carried out on the modified dental implants. In vitro cell culture study reported enhanced osteogenic activity on the drug-loaded nanotube surface implants. The invivo animal studies were evaluated by micro-CT, histopathology, and reverse torque removal analysis methods. The test results showed faster osseointegration with the strong interface on the Simvastatin drug-loaded implant surface at 4 weeks of healing as compared to the control implants.
ABSTRACT
INTRODUCTION: This study aimed to compare root dentinal microcrack formation after root canal shaping using rotary, reciprocating, and adaptive instruments at different working lengths using micro-computed tomographic imaging. METHODS: One hundred eighty extracted mature mandibular molar mesial roots with 2 separate canals were selected. The mesial roots were resected at the cementoenamel junction and randomly divided into 4 groups (n = 45) based on the nickel-titanium file system used: ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland), ProTaper Gold (Dentsply Maillefer), Twisted File Adaptive (SybronEndo, Orange, CA), and Reciproc Blue (VDW, Munich, Germany). Each of the 4 groups were then subdivided into 3 groups (n = 15) depending on the working length used for root canal preparation (ie, instrumentation 1 mm short, flush, and 1 mm beyond the major apical foramen). The roots were imaged with micro-computed tomographic scanning before and after root canal preparation. The cross-sectional images generated were screened to detect the presence of new microcracks. RESULTS: The ProTaper Universal system significantly increased the number of postinstrumentation microcracks at all working lengths (P ≤ .05). No significant increase (P > .05) in postinstrumentation microcracks was observed in the ProTaper Gold, Twisted File Adaptive, or Reciproc Blue groups. CONCLUSIONS: Rotary instrumentation induced a higher number of dentinal microcracks compared with reciprocating and adaptive instruments. Instrumentation at different working lengths did not significantly influence the formation of dentinal microcracks.