ABSTRACT
This study examined the bone response to titanium dioxide nanotube modified implants. A total of 24 implants were placed in the femur of 4 beagles. Before placement, screw-shaped implants were classified into 3 groups; machined surface (group M), titanium dioxide nanotube modification of the machined surface (group MN) and titanium dioxide nanotube modification of the RBM surface (group RN). The texture morphology was observed via scanning electron microscopy. Animals were euthanized after 4 and 12 weeks of submerged healing and the histologic and histomorphometric analyses were performed. Groups MN and RN showed a significantly higher percentage of mineralized bone than that in group M (p < 0.05). The results of this in vivo study constitute significant evidence that the presence of the titanium dioxide nanotubes enhance osseointegration of implants.
Subject(s)
Bone Development , Nanotubes , Prostheses and Implants , Titanium/pharmacology , Animals , Dogs , Microscopy, Electron, ScanningABSTRACT
The purpose of this study was to evaluate the stress distribution produced in the dentoalveolar system by a maxillary posterior crossbite appliance used for the correction of maxillary second molars in buccal crossbite. A photoelastic model was fabricated using a photoelastic material (PL-3) to simulate alveolar bone and ivory-colored resin teeth. The model was anteriorly and posteriorly observed with a circular polariscope and photographically recorded before and after activation of the maxillary posterior crossbite appliance. An uncontrolled palatal tipping and a rotating force were generated when the traction force was applied on the palatal surface of the maxillary second molar. A controlled tipping and an intrusive force were generated when the traction force was applied on the buccal surface of the maxillary second molar.
Subject(s)
Alveolar Process/physiopathology , Malocclusion/therapy , Molar/physiopathology , Orthodontic Appliances , Humans , Malocclusion/physiopathology , Maxilla/physiopathology , Models, Anatomic , Orthodontic Appliance Design , Orthodontic Wires , Palate/physiopathology , Photography , Photometry , Rotation , Stress, Mechanical , Tooth Apex/physiopathology , Tooth Movement Techniques/instrumentation , Tooth Root/physiopathologyABSTRACT
The purpose of this study was to evaluate the stress distribution produced in the dentoalveolar system by a mandibular posterior crossbite appliance used for the correction of mandibular second molars in lingual version. A photoelastic model was fabricated using a photoelastic material (PL-3) to simulate alvelolar bone and ivory-colored resin teeth. The model was observed anteriorly and posteriorly with a circular polariscope and photographically recorded before and after activation of mandibular posterior crossbite appliances. An uncontrolled tipping and an extrusive force were generated when the traction force was applied on the buccal surface of the mandibular second molar. A controlled tipping and an intrusive force were generated when the traction force was applied on the lingual surface of the mandibular second molar. We concluded that to escape the extrusion and uncontrolled tipping that creates occlusal interferences associated with the correction of mandibular second molars in lingual version, the lingual traction force is more useful than the buccal traction force.
