Restorative Dentistry: Properties, Treatment Planning, and Evaluation
1. Electric Pulp Testing
The electric pulp tester is placed on a dry tooth surface. A small electrical current is delivered to the tooth, causing a tingling sensation when the pulp is vital and no response when the pulp is nonvital. Readings from adjacent teeth should be obtained for comparison. However, this method can produce false positive and false negative readings.
2. Thermal Testing (Heat and Cold)
A cotton applicator tip sprayed with a freezing agent (e.g., Histofreeze) or hot gutta-percha is applied directly to the tooth. The duration of pain helps determine the pulp condition:
- Pain lasting 10-15 seconds or less: Suggests hyperemia, a reversible inflammation (Reversible Pulpitis).
- Intense pain of longer duration: Suggests irreversible pulpitis (Irreversible Pulpitis).
- Lack of response: Indicates necrotic pulp.
3. Phases of Treatment Plan Sequencing
Urgent Phase
Addresses immediate concerns like swelling, pain, bleeding, or infection.
Control Phase
- Eliminates active disease (caries, inflammation).
- Removes obstacles to maintenance.
- Eliminates potential disease causes.
- Begins preventive dentistry.
Re-evaluation Phase (Holding Phase)
Allows time for healing and inflammation resolution, reinforces home care, and assesses motivation for further treatment.
Definitive Phase (Corrective Phase)
Includes procedures like endodontics, periodontics, orthodontics, oral surgery, and operative procedures before fixed or removable prosthodontic treatment.
Maintenance Phase
Includes regular recall examinations to monitor for issues and reinforce home care.
4. Percolation
Percolation is the movement of fluids at the interface of a restoration and the tooth. It’s caused by the difference in thermal expansion and contraction between the two materials. This difference is directly proportional to the amount of percolation and subsequent marginal leakage. Ideally, the restorative material should have a coefficient of thermal expansion similar to tooth structure.
Example:
- Metallic fillings shrink at lower temperatures, allowing influx of oral fluids.
- Metallic fillings expand at higher temperatures, causing efflux of oral fluids.
5. Properties of Restorative Materials
Dimensional Stability
Minimal shrinkage or expansion after placement is crucial. Slight expansion can be beneficial for sealing.
Percolation (as described above)
Strength
Must withstand masticatory forces. Thicker restorations generally have greater strength.
Adaptability
Close fit and mechanical interlocking between the restoration and cavity walls are essential.
Bonding
Ideally, both chemical and physical bonding to the tooth structure.
Solubility Resistance
The restoration should not dissolve or degrade in the oral environment.
Abrasion Resistance
Important for occlusal and incisal surfaces to resist wear and tear.
Thermal Conductivity
Low thermal conductivity is preferred to minimize pulpal irritation. Liners and bases can provide protection in deeper cavities.
Manipulation
Easy mixing and placement procedures are desirable.
Resistance to Tarnish and Corrosion
Prevents degradation of the restoration surface. Gold and ceramics are highly resistant.
6. Conditions Encountered When Evaluating Amalgam Restorations
- Amalgam “blues”
- Proximal overhangs
- Marginal ditching
- Voids
- Fracture lines
- Lines between abutted restorations
- Improper anatomic contours
- Marginal ridge incompatibility
- Improper proximal contacts
- Recurrent caries
- Improper occlusal contacts