ABSTRACT
Fabricating a ceramic restoration for a discolored anterior tooth presents a clinical challenge. The dental technician is often hampered by being unaware of the shade of the discolored tooth preparation, which influences the color of the overlying ceramic restoration. A definitive cast that replicates the shade of the prepared tooth helps the ceramist to fabricate a restoration that masks the discoloration appropriately and still achieves the desired optical properties. This report demonstrates the use of a technique of recording and communicating the shade of a prepared tooth to the dental laboratory technician.
Subject(s)
Dental Restoration, Permanent/methods , Tooth Discoloration/diagnosis , Tooth Preparation, Prosthodontic/methods , Ceramics/therapeutic use , Communication , Dental Casting Technique , Dental Materials/therapeutic use , Female , Humans , Incisor/pathology , Young AdultABSTRACT
PURPOSE: To evaluate the shear bond strength (SBS) between zirconia and veneering ceramic following different surface treatments of zirconia. The efficacy of an experimental zirconia coating to improve the bond strength was also evaluated. MATERIALS AND METHODS: Zirconia strips were fabricated and were divided into four groups as per their surface treatment: polished (control), airborne-particle abrasion, laser irradiation, and application of the experimental coating. The surface roughness and the residual monoclinic content were evaluated before and after the respective surface treatments. A scanning electron microscope (SEM) analysis of the experimental surfaces was performed. All specimens were subjected to shear force in a universal testing machine. The SBS values were analyzed with one-way ANOVA followed by Bonferroni post hoc for groupwise comparisons. The fractured specimens were examined to observe the failure mode. RESULTS: The SBS (29.17 MPa) and roughness values (0.80) of the experimental coating group were the highest among the groups. The residual monoclinic content was minimal (0.32) when compared to the remaining test groups. SEM analysis revealed a homogenous surface well adhered to an undamaged zirconia base. The other test groups showed destruction of the zirconia surface. The analysis of failure following bond strength testing showed entirely cohesive failures in the veneering ceramic in all study groups. CONCLUSION: The experimental zirconia surface coating is a simple technique to increase the microroughness of the zirconia surface, and thereby improve the SBS to the veneering ceramic. It results in the least monoclinic content and produces no structural damage to the zirconia substructure.
Subject(s)
Ceramics/chemistry , Coated Materials, Biocompatible/chemistry , Dental Bonding , Dental Materials/chemistry , Dental Veneers , Zirconium/chemistry , Aluminum Oxide/chemistry , Carbon Compounds, Inorganic/chemistry , Ceramics/radiation effects , Coated Materials, Biocompatible/radiation effects , Dental Etching/methods , Dental Materials/radiation effects , Dental Polishing/methods , Dental Stress Analysis/instrumentation , Humans , Lasers, Solid-State , Materials Testing , Microscopy, Electron, Scanning , Shear Strength , Silicon Compounds/chemistry , Stress, Mechanical , Surface Properties , Zirconium/radiation effectsABSTRACT
OBJECTIVE: The location and inter relationship of the structures of the inferior alveolar neurovascular bundle within the mandibular canal has not been clearly defined. The knowledge of the same is important while planning surgeries in the posterior mandible. METHODS: Eight cadaveric mandibles were dissected and sections were made at the distal aspect of every tooth. The inferior alveolar neurovascular bundle was identified and examined for the location of the inferior alveolar artery, vein and nerve. Hematoxylin and Eosin sections were made for each specimen to confirm the position of these structures. RESULTS: All the sections in all the specimens confirmed that a blood vessel lies superior to the nerve. This position appeared consistent in all the positions relative to all the posterior teeth. There was a variation in the bucco-lingual positioning of these structures relative to each other for the various mandibles. CONCLUSION: A blood vessel is found to always lie superior to the inferior alveolar nerve within the mandibular canal. Variations in the inter relationship of the structures is present. SIGNIFICANCE: This cadaveric study proves that all along the course of the neurovascular bundle, at various cross-sections studied, the inferior nerve is always inferior to a blood vessel. There can be great variations to the positioning of the structures within the neurovascular bundle in the bucco-lingual dimension and also in the exit of the nerve in various mandibles. Knowledge of the location of the structures is of importance during surgical procedures carried out in the vicinity of these structures.
