Podcast
Questions and Answers
What is the primary advantage of using high-copper alloys over low-copper alloys?
What is the primary advantage of using high-copper alloys over low-copper alloys?
What is the recommended mercury-to-alloy ratio according to Eames' technique?
What is the recommended mercury-to-alloy ratio according to Eames' technique?
Why are spherical particle alloys preferred over lathe-cut alloys?
Why are spherical particle alloys preferred over lathe-cut alloys?
In which scenario should non-zinc containing alloys be used?
In which scenario should non-zinc containing alloys be used?
Signup and view all the answers
What is a disadvantage of using bulk bottles for dispensing amalgam components?
What is a disadvantage of using bulk bottles for dispensing amalgam components?
Signup and view all the answers
For spherical alloys, what is the recommended mercury content compared to their volume?
For spherical alloys, what is the recommended mercury content compared to their volume?
Signup and view all the answers
Which dispensing method provides pre-proportioned amounts of mercury and alloy?
Which dispensing method provides pre-proportioned amounts of mercury and alloy?
Signup and view all the answers
What characteristic of finer particle sizes benefits amalgam handling?
What characteristic of finer particle sizes benefits amalgam handling?
Signup and view all the answers
What is the primary purpose of trituration in the amalgamation process?
What is the primary purpose of trituration in the amalgamation process?
Signup and view all the answers
Which type of amalgamator is more convenient for mixing but also more expensive?
Which type of amalgamator is more convenient for mixing but also more expensive?
Signup and view all the answers
What advantage does a mechanical amalgamator provide over hand trituration?
What advantage does a mechanical amalgamator provide over hand trituration?
Signup and view all the answers
What should be controlled during hand trituration to ensure effectiveness?
What should be controlled during hand trituration to ensure effectiveness?
Signup and view all the answers
Which material is preferred for mortars used in hand trituration due to its texture?
Which material is preferred for mortars used in hand trituration due to its texture?
Signup and view all the answers
In the context of mechanical amalgamators, what is a key feature of those using capsules?
In the context of mechanical amalgamators, what is a key feature of those using capsules?
Signup and view all the answers
What is the primary function of the amalgamator's oscillation in a figure ‘8’ pattern?
What is the primary function of the amalgamator's oscillation in a figure ‘8’ pattern?
Signup and view all the answers
What is the primary benefit of using an amalgamator without capsules?
What is the primary benefit of using an amalgamator without capsules?
Signup and view all the answers
What is the primary purpose of pre-carve burnishing?
What is the primary purpose of pre-carve burnishing?
Signup and view all the answers
Which instrument is typically used for post-carve burnishing?
Which instrument is typically used for post-carve burnishing?
Signup and view all the answers
What is a potential consequence of performing carving before burnishing?
What is a potential consequence of performing carving before burnishing?
Signup and view all the answers
What sound should be heard during post-carve burnishing to indicate readiness?
What sound should be heard during post-carve burnishing to indicate readiness?
Signup and view all the answers
What is one of the main objectives of carving in dental restoration?
What is one of the main objectives of carving in dental restoration?
Signup and view all the answers
Which benefit does post-carve burnishing provide to the restoration?
Which benefit does post-carve burnishing provide to the restoration?
Signup and view all the answers
How does pre-carve burnishing affect the amount of mercury in the amalgam?
How does pre-carve burnishing affect the amount of mercury in the amalgam?
Signup and view all the answers
What potential issue may arise from not performing carving correctly?
What potential issue may arise from not performing carving correctly?
Signup and view all the answers
What is the primary purpose of using amalgam knives in dental restoration?
What is the primary purpose of using amalgam knives in dental restoration?
Signup and view all the answers
What does the process of checking occlusion involve?
What does the process of checking occlusion involve?
Signup and view all the answers
Why is finishing and polishing of amalgam considered important?
Why is finishing and polishing of amalgam considered important?
Signup and view all the answers
What should be avoided during the first 7-8 hours after placement of a silver amalgam restoration?
What should be avoided during the first 7-8 hours after placement of a silver amalgam restoration?
Signup and view all the answers
Which material is primarily used for reducing high points in the finishing phase?
Which material is primarily used for reducing high points in the finishing phase?
Signup and view all the answers
What is the consequence of not allowing silver amalgam to set for the recommended 24 hours?
What is the consequence of not allowing silver amalgam to set for the recommended 24 hours?
Signup and view all the answers
What is the role of the finishing burs or stones during the finishing process?
What is the role of the finishing burs or stones during the finishing process?
Signup and view all the answers
Which step comes first in the finishing process of proximo-occlusal restoration?
Which step comes first in the finishing process of proximo-occlusal restoration?
Signup and view all the answers
What is the primary purpose of using fine finishing strips in the cervical areas?
What is the primary purpose of using fine finishing strips in the cervical areas?
Signup and view all the answers
Which polishing agent is NOT mentioned as a component to obtain final polish or metallic luster?
Which polishing agent is NOT mentioned as a component to obtain final polish or metallic luster?
Signup and view all the answers
Which is a significant hazard associated with the polishing of amalgam restorations?
Which is a significant hazard associated with the polishing of amalgam restorations?
Signup and view all the answers
What is the threshold limit value for exposure to mercury vapor during a typical work week?
What is the threshold limit value for exposure to mercury vapor during a typical work week?
Signup and view all the answers
Which of the following routes is NOT a common way for mercury to enter the human body?
Which of the following routes is NOT a common way for mercury to enter the human body?
Signup and view all the answers
Which condition is a potential effect of long-term exposure to mercury vapors?
Which condition is a potential effect of long-term exposure to mercury vapors?
Signup and view all the answers
What material is indicated for the preliminary polishing of amalgam restorations?
What material is indicated for the preliminary polishing of amalgam restorations?
Signup and view all the answers
During which procedure is mercury vapor particularly released, posing health risks?
During which procedure is mercury vapor particularly released, posing health risks?
Signup and view all the answers
Study Notes
Amalgam Restoration Technique
- Alloy Selection: High-copper alloys are preferred for clinical use because they do not contain the weak γ2 phase. High-copper alloys also exhibit good corrosion resistance and low creep. Finer particle sizes are easier to handle, dispense, and result in a smoother surface. Spherical particle alloys are better than lathe-cut alloys as they require less condensation pressure and mercury for trituration. Non-zinc containing alloys are used only when moisture control is difficult.
- Proportioning (Mercury:Alloy Ratio): The minimal mercury technique (Eames’ technique) is the most acceptable. The recommended mercury-to-alloy ratio is 1:1 by volume (50% mercury content). For spherical alloys, the recommended mercury amount is closer to 42% due to their lower surface-to-volume ratio.
-
Dispensing: Various dispensers are available for mercury and alloy:
- Bottles containing bulk mercury and alloy powder for proportioning by the dentist.
- Pre-weighed pellets of alloy in different sizes allowing for mixing with appropriate mercury amounts.
- Disposable capsules containing pre-proportioned aliquots of mercury and alloy, separated by a membrane. Newer self-activating capsules rupture automatically in the amalgamator.
- Reusable capsules allowing for dispensing of alloy pellets and mercury from an automatic bottle. The capsule is mixed with an amalgamator oscillating in a figure eight pattern.
Trituration
- Definition: The process of mixing amalgam alloy particles with mercury.
-
Objectives:
- Remove oxides from alloy particle surfaces to facilitate direct contact with mercury.
- Achieve a workable mass of amalgam in minimal time allowing for insertion into the cavity.
-
Methods:
- Hand Trituration: Using a mortar and pestle (glass or ceramic). The mortar should rest on a firm base, pressure should be uniform, and mixing time should be controlled. A rough surface texture is important for oxide removal and proper coating of alloy particles.
- Mechanical Trituration: Using an amalgamator. This can be capsule-free or capsule-based. In the capsule-free system, alloy powder and mercury are placed in bulk compartments and mixed based on manually set time and material amounts.
Burnishing
- Definition: Smoothing a rough restoration surface using a rigid instrument.
-
Objectives:
- Continue condensation, reducing voids on the surface and marginal area.
- Bring excess mercury to the surface for removal during carving.
- Adapt the amalgam to prepared tooth margins.
-
Types:
- Pre-Carve Burnishing: Continuation of condensation, carried out before carving using a large egg-shaped or ball burnisher.
- Post-Carve Burnishing: Smoothing the rough surface after carving using a small-sized burnisher with light strokes. It reduces voids, improves marginal seal, and achieves a satin/velvet finish.
Carving
- Definition: Anatomical sculpturing of amalgam for re-obtaining the original tooth anatomy.
-
Objectives:
- Create a restoration with proper contours and no overhangs.
- Produce a restoration with adequate marginal ridges, proper contact areas, and embrasures.
- Remove gingival excess and prevent gingival overhangs.
- Refine embrasure form around proximal contacts.
Checking Occlusion
-
Procedure:
- Use articulating papers (blue, green, or red) to check for high points on the restoration.
- Place the paper on the restored tooth and ask the patient to bite.
- High points will show as darker imprints on the paper.
- Remove high points using a carver and repeat the process until no high points remain.
Finishing and Polishing
-
Objectives:
- Reduce plaque accumulation and decrease the risk of secondary caries.
- Decrease the risk of failure under masticatory load.
- Improve amalgam hardness and strength.
- Remove scratches and irregularities.
- Decrease overhangs and plaque adherence to prevent corrosion.
-
Procedure:
- Leave the restoration undisturbed for 24 hours to allow for complete setting.
- Finish using finishing burs or stones to trim margins, create contours, and correct occlusal disharmonies.
- Reduce high points using carborundum stones.
- Begin cervical finishing, followed by buccal/lingual margins, then occlusal margins.
- Remove overhangs using trimmers and amalgam knives.
- Finish cervical areas with interdental finishing strips.
- Smoothen facial/lingual margins with cuttlefish sandpaper discs.
- Use abrasives in descending order (coarse, medium, fine, ultrafine) as an amalgam polishing kit.
- Achieve final polish by applying polishing agents (tin oxide, zinc oxide chalk, and pumice).
- Use polishing strips and dental tapes for cervical areas.
-
Hazards:
- Aerosol production.
- Pulp damage from high temperatures.
- Mercury surfacing and early staining from high temperatures.
- Mercury vapour inhalation.
Mercury in Dental Amalgam
-
Requirements for Mercury Use:
- Arsenic-free.
- Non-volatile residue less than 0.02%.
-
Mercury Hazards:
- Mercury can enter the body through skin, gastrointestinal tract, and respiratory tract.
- Respiratory exposure is most common due to mercury vapour inhalation.
- Long-term vapour exposure causes nervous system disturbances, irritation, tremors, verbal skill impairment, depression, and memory loss.
- Threshold Limit Value (TLV): 50 µg/m3 of air for a 40-hour workweek.
-
Sources of Mercury Hazards:
- Mercury vapour from unsealed bottles.
- Mercury release from capsules during trituration.
- Mercury spillage during manipulation.
- Vapour release during amalgam placement, polishing, and removal.
- Contamination of cotton rolls.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on the amalgam restoration technique, focusing on alloy selection, mercury-to-alloy ratios, and dispensing methods. This quiz covers essential information for practicing dentists and dental students. Understand the properties of high-copper alloys and the best practices for their use in clinical settings.
