Zirconia: properties and application - a review

Over the last decade, zirconia has propelled a rapid development of metal-free dentistry with improved material strength, enhanced esthethic and high biocompatibility for a wide range of promising clinical applications. It holds a unique place amongst the oxide ceramics due to its excellent mechanical properties owing to the phase transformation toughening mechanism. Like other side of the same coin, this mechanism is also responsible for its low temperature degradation which is the main limiting factor in the extensive use of zirconia. Zirconia is an inert material and presents reduced bond strength with the conventional ceramic cementation procedures. Bonding to traditional silica based ceramics is a predicta. A high percentage of clinical failures of zirconia-based restorations are attributed to debonding and or fracture of veneering ceramic. This review presents the properties, types of zirconia for dental application, the manufacturing procedures, the various application and its guidelines, luting of zirconia and bonding of the veneering ceramics

Diagnostic cast - a forgotten diagnostic tool

Dentists are challenged to create solutions for problems that patients present from chipped or missing teeth, a collapsed bite, or teeth that are irregular or misshapen. A clear diagnosis of the condition often is required for a proper treatment planning. The diagnostic cast helps the dentist to evaluate the condition of the patient's oral condition and for the diagnostic purposes. Casts may also be used as education tools for dentists as they explain characteristics of a patient's bite or particular dental needs. They can also show how a restoration will look when the work is complete

Comparative evaluation of the accuracy of two methods of occlusal registration involving terminal abutments - an invivo study

Purpose of the study was to evaluate the accuracy of interocclusal records made in the terminal abutment region by two recording techniques. Ten partially edentulous patients planned for replacement of missing mandibular molars with fixed partial denture were selected. For each patient three sets of articulations were made. Articulation I - Pre operative casts: Preoperative maxillary and mandibular casts mounted in an articulator. Measurements were made from the deepest part of the marginal gingiva in the maxillary and mandibular teeth using a travelling microscope. Articulation II - Inter occlusal record with centric stop: Complete crown preparation was done for both mesial and distal abutments, preserving the centric stop in the distal abutment. Casts obtained were articulated using an inter occlusal record. Measurements between the maxillary and mandibular casts measured at the same area as the preoperative cast. Articulation III-Inter occlusal record without a centric stop: The centric stop retained was reduced to complete the preparation and a third set of cast articulated with another inter occlusal record. Measurements between the maxillary and mandibular casts measured at the same area as the preoperative cast. The values obtained were statically analyzed. Within the limitations of the study, presence of inter occlusal record in both the techniques showed an increase in vertical discrepancy. Clinical Implication: Making interocclusal records with vertical stop shows increased vertical discrepancy