Resto beq PDF

Preview

Summary

A gold onlay you placed last week fails, which of the following reasons is most likely responsible for the failure? a. You "capped" the functional cusp b. You "shoed" the functional cusp c. You "capped" the nonfunctional cusp d. You "sho...

Description

1. A gold onlay you placed last week fails, which of the following reasons is most likely responsible for the failure? a. You "capped" the functional cusp b. You "shoed" the functional cusp c. You "capped" the nonfunctional cusp d. You "shoed" the nonfunctional cusp ➢ “Capping” refers to complete coverage of functional cusp with 1.5mm of gold. ➢ “shoeing” refers to veneering of nonfunctional cusp by means of slight finishing bevel. Source: Dental Decks Part II 2016 – Gold – Operative Dentistry 2. Rapid cooling (by immersion in water) of a dental casting from the high temperature at which it has been shaped is referred to as: a. Annealing b. Tempering c. Quenching d. None of the above ➢ This usually is undertaken to maintain mechanical properties associated with a crystalline structure or phase distribution that would be lost on slow cooling. Source: Dental Decks Part II 2016 – Gold – Operative Dentistry 3. Which of the following situations defines an indication for class 2 gold inlay? a. A young patient with high caries rate b. A patient with little money to invest in dental work c. A patient very concerned in esthetics d. A patient with large lesion, bucco-lingually e. A patient with low caries rate, but a history of periodontal problems ➢ Advantages and indications of Class II gold inlay: o Tooth Contours- where optimum contour and surface finish is desired to maintan periodontal health o Strength o In patients with low caries rate o Use against another gold restoration o biocompatible Source: Dental Decks Part II 2016 – Gold – Operative Dentistry 4. Gold alloys _____ upon solidification in the investment, this needs to be compensated for by an equal amount of __ in the mold a. Shrink, expansion b. Expand shrinkage

c. Shrink, shrinkage d. Expand, expansion ➢ Gypsum bonded investments are used with Type 1, 2, 3 gold alloys. Gold alloys used for cast gold restorations shrink upon solidification. Therefore, it is necessary to compensate for the solidification shrinkage of the specific alloy used by expanding the mold enough to equal the shrinkage. Source: Dental Decks Part II 2016 – Gold – Operative Dentistry 5. Which of the following allows for proper retention when preparing a tooth for a distoocclusal class 2 gold inlay? a. Undercut on mesial b. Undercut on buccal and lingual walls c. Occlusal lock (dovetail) d. None of the above ➢ An occlusal lock or dovetail should be established to prevent proximal dislodgement Source: Dental Decks Part II 2016 – Gold – Operative Dentistry 6. A patient came to your office with their full gold crown in hand. They explained to you that another dentist delivered it just last week. You then examine the crown and the preparation, what is the most likely reason the crown fell off? a. There was very little cement in the crown b. The preparation was only 4mm high c. The preparation walls were tapered at about 15 degrees d. The margins are jagged and undefined ➢ For maximum retention of cast gold restorations, the axial walls should be as parallel as possible and as long as possible. Retention is directly proportional to the area of the axial walls and their parallelism. No undercuts should be present. Source: Dental Decks Part II 2016 – Gold – Operative Dentistry 7. The lab calls your office and ask if you want a particular casting done in a base or a noble metal. Which of the following responses are appropriate? a. Base, because the patient has a bad bruxism habit b. Noble, because the patient has a bad bruxism habit c. Base, because the patient wants a gold tooth d. Noble, because the patient wants a gold tooth ➢ Base metal alloy advantages are principally focused only in their strength and low density. Source: Dental Decks Part II 2016 – Gold – Operative Dentistry

8. Of the following, which is not a correct match between the gold cast alloy component and its effect? a. Gold - decreases ductility and malleability b. Gold - increases resistance to tarnish and corrosion c. Copper - hardens the alloy d. Silver - color modifying ➢ Gold actually increases ductility and malleability. It also increases resistance to tarnish and corrosion. Source: Dental Decks Part II 2016 – Gold – Operative Dentistry 9. High gold alloys used for cast restorations are: a. Greater than 20% gold or other noble metals b. Greater than 30% gold or other noble metals c. Greater than 50% gold or other noble metals d. Greater than 75% gold or other noble metals ➢ ADA type I – highest gold content, intended for small inlays, easily burnished due to high ductility ➢ ADA type II – greater than 78% noble metals. Intended for larger inlays and onlays. Can also be burnished ➢ ADA type III – greater than 75% noble metals. For onlays and crowns, capable of being heat treated ➢ ADA type IV – greater than 75% noble metals. Intended for bridges and removable partial dentures, Hardest of all high gold alloys. Source: Dental Decks Part II 2016 – Gold – Operative Dentistry

10. The following statements describe an MOD gold cast onlay preparation. Which would you have to change to ensure that the onlay will be successful? a. The mesial box has axiopulpal line angle that is longer than facial to lingual than the axiogingival line angle b. From facial to lingual, the distal axiopulpal line angle is longer than mesial axiopulpal line angle c. The mesial and distal line angle converges d. The distal box has an axiopulpal line angle that is shorter from facial to lingual than the axiogingival line angle ➢ From facial to lingual, the axiopulpal line angle of an onlay preparation is longer than the axiogingival line angle. For an MOD onlay prep, the axial walls must converge from the gingival walls to the pulpal wall. Source: Dental Decks Part II 2016 – Gold – Operative Dentistry

11. Dental wax patterns (i.e., inlays, onlays, crowns) should be invested as soon as possible after fabricating to minimize changes in the shape caused by: a. Reduced flow b. Drying of the wax c. Relaxation of the internal stress d. Continued expansion of the wax ➢ However the pattern is prepared, it should be an accurate reproduction of the missing tooth structure. The casting can be no more accurate than the wax pattern. The wax pattern should be invested as soon as possible after fabrication in order to minimize changes in shape caused by relaxation of the internal stresses in the wax. Source: Dental Decks Part II 2016 – Gold – Operative Dentistry

12. All of the following are indications for gold cast onlay except one, which one is the exception? a. Restoration large lesion b. Restoration of ideal occlusion in cases of drifting, hypo and hper eruption c. Restoration of optimum contour and proximal contact d. Restoration of a tooth with minimal ferrule, when a full coverage crown would not have enough retention ➢ If a tooth is not a candidate for a full coverage crowns, it is not a candidate for onlay. A tooth that does not have a minimum of 1.5 mm of ferrule effect will need a more build up, crown lengthening or both. Source: Dental Decks Part II 2016 – Gold – Operative Dentistry

13. You are preparing tooth #36for a modb gold onlay and tooth #37 modb amalgam restoration, which of the following two statements correctly describe the difference in your preparations of the functional cusp? a. You will need 2.5 to 3mm of reduction for gold b. You will need 2.5 to 3mm of reduction for amalgam c. You will need 1.5mm reduction for gold d. You will need 1.5mm reduction for amalgam ➢ Minimal Occlusal reduction: ➢ Working cusp: 2.5 – 3.0 mm- amalgam; 1.5mm – cast gold; 1.5 – 2.0mm – metal ceramic ➢ Non working cusp: 2.0mm amalgam; 1.0mm – cast gold; 1.5 – 2.0mm metal ceramic

Source: Dental Decks Part II 2016 – Gold – Operative Dentistry 14. An Indirect tooth colored restoration indicated for class 1 and 2 restorations located in areas where esthetic is important to the patient. a. veneers b. inlay /onlay c. Crowns d. FRC resin >Esthetics: Indirect tooth-colored restorations are indicated for Class I and II restorations (inlays and onlays) located in areas of esthetic importance for the patient. Source: (Sturdevant’s Art and Science of Operative Dentistry 6th edition, page 280). 15. Indirect tooth colored restorations made of ceramics usually fractures due to the following, except one. a. heavy occlusal forces b. Lack sufficient thickness c. Bruxism habits d. Insufficient contours and bevels of the preparation >Heavy occlusal forces: Ceramic restorations can fracture when they lack sufficient thickness or are subject to excessive occlusal stress, as in patients who have bruxing or clenching habits. Heavy wear facets or a lack of occlusal enamel are good indicators of bruxing and clenching habits. Source: (Sturdevant’s Art and Science of Operative Dentistry 6th edition, page 280). 16. Deep subginvival preparation is one of the contraindications of indirect tooth colored restoration, because of the following, except one: a. margins are not visible by the clinician, giving difficulty to evaluate and finish b. Margins are difficult to record with an elastomeric or even a digital impression c. Poor Dentin bond strength at gingival floor d. Blood subgingivally may produce stain and discoloration of the restorative material. >Deep subgingival preparations: Although this is not an absolute contraindication, preparations with deep subgingival margins generally should be avoided. These margins are difficult to record with an elastomeric or even a digital impression and are difficult to evaluate and finish. Additionally, dentin bond strengths at gingival floors are not particularly good, so bonding to enamel margins is greatly preferred, especially along gingival margins of proximal boxes. Source: (Sturdevant’s Art and Science of Operative Dentistry 6th edition, page 280).

17. Aside from reduced polymerization shrinkage, clinical studies show that the following are advantages of Ceramic inlays and onlays compared to direct composite restoration, except one: a. better marginal adaptation b. Improved Anatomic form and color match c. Overall survival rate d. None of the above >clinical studies indicate ceramic inlays and onlays have better marginal adaptation, anatomic form, color match, and overall survival rates than do direct composite restorations. Source: (Sturdevant’s Art and Science of Operative Dentistry 6th edition, page 281).

18. Type of etchant used to the internal surface of the ceramic onlay prior to cementation. a. 37% phosphoric acid b. 17% EDTA c. Hydrofluoric acid d. All of the above >HF acid or a similar acid usually is used to etch the internal surfaces of the restoration; applying HF acid to the internal surface of the ceramic onlay. After rinsing and drying, etched ceramic surfaces should have a frosty white appearance. Source: (Sturdevant’s Art and Science of Operative Dentistry 6th edition, page 29).

19. Restorative material used to cement ceramic onlays to the etched prepared tooth. a. self-cure acrylics b. Glass ionomer c. Dual cure resin cements d. Resin modified glass ionomer >A dual-cure resin cement is mixed and inserted into the preparation with a paddle-shaped instrument or a syringe. The internal surfaces of the restoration also are coated with the resin cement, and using light pressure, the restoration is immediately inserted into the prepared tooth. Source: (Sturdevant’s Art and Science of Operative Dentistry 6th edition, page 292). 20. In finishing and polishing of ceramic restorations, arrange the following instruments in sequence. 1)30 fluted carbide burs 2)Diamond polishing paste 3)Medium grit to fine grit diamond rotary instrument

4)Sequence of rubber, abrasive-impregnated porcelain polishing points a. 1, 3, 2, 4 b. 3, 1, 4, 2 c. 3, 1, 2, 4 d. 1, 3, 4, 2 >Table 11-1 Instrumentation for Finishing and Polishing Ceramic Restorations Sequence Instruments 1 Medium-grit to fine-grit diamond rotary instrument 2 30-fluted carbide burs 3 Sequence of rubber, abrasive-impregnated porcelain polishing points 4 Diamond polishing paste Source: (Sturdevant’s Art and Science of Operative Dentistry 6th edition, page 292)....