LLUSD - Chapter 4 - Implant Device Surfaces Micro-retentive features are developed by additive methods or subtractive methods.*TrueFalseCommercially pure titanium is available in 4 grades.*TrueFalseThe main difference between the grades of pure titanium and the alloys is the increasing ultimate tensile strength and the amount of oxygen and hydrogen.*FalseTrueAirborne particle abrasion is an additive method of creating micro-retentive features.*TrueFalseThe amount of bone contact with the implant surface is one means that has been used to improve implant success.*TrueFalseTitanium forms an oxide layer that has an initial thickness of 50 to 100 Angstroms.*FalseTrueAn initial blood clot forms around the surgical site without the presence of an inflammatory response.*TrueFalseTitanium alloys include aluminum and zirconium.*FalseTruePresently, there are 9 types of titanium based materials used to fabricate dental implants.*FalseTrueSome implant designs incorporate two or more thread profiles that cut at different relative locations in the bone so the implant can engage both cortical and cancelleous bone with the same degree of intensity.*TrueFalseHydroxyapatite spraying is an additive method.*FalseTrueWhen the oxide layer is evaluated after several years in the mouth, it is thicker and has been found to contain organic materials as well as inorganic (Ca, P, and S) materials.*FalseTrueThe purpose of threads on implants is to enhance initial stability in the bone and create spaces for bone ingrowth.*TrueFalse
