Impressions
Step-by-Step Instructions for Taking a Dental Impression
Prepare Necessary Materials:
Impression tray (appropriate size)
Impression material (alginate or silicone)
Mixing bowl and spatula
Measuring cups for powder and water
Protective gloves and mask
Paper towels for cleanup
Choose the Right Impression Tray:
Select a tray that fits comfortably in the patient's mouth and covers the dental arches adequately.
Ensure the tray is clean and free from debris.
Apply adhesive to the tray
Measure and Mix Impression Material:
Following the manufacturer’s instructions, measure the correct ratio of impression material powder to water.
Combine the powder and water in the mixing bowl.
Use the spatula to mix until a smooth, homogenous consistency is achieved with no lumps.
Load the Impression Tray:
Using the spatula, fill the selected impression tray with the mixed impression material.
Ensure it is filled adequately and evenly without air bubbles.
Prepare the Patient:
Explain the procedure to the patient to make them comfortable.
Place a protective towel or bib over the patient’s clothes.
Position the Impression Tray:
Gently insert the loaded impression tray into the patient’s mouth, ensuring it is positioned correctly over the dental arch.
Press down firmly but gently to ensure it makes good contact with the gums and teeth.
Instruct the Patient to Bite Down:
Ask the patient to close their mouth gently. This ensures the impression material captures all relevant structures.
Keep the tray steady and avoid any movement for the designated setting time (refer to the material's instructions).
Remove the Impression Tray:
Once the impression material has set (usually within a few minutes), gently rock the tray back and forth to break the seal before removing it.
Carefully remove the tray from the patient’s mouth.
Inspect the Impression:
Check the impression for accuracy and detail, ensuring that all teeth, gums, and vestibular areas are captured.
Look for any voids or air bubbles that may affect the quality of the impression.
Clean Up:
Rinse the impression with water to remove saliva and adhere to dental hygiene protocols.
Clean the impression tray and any other materials used during the process.
Store or Pour the Impression:
Depending on the procedure, you can either pour the impression immediately or store it according to the manufacturer's instructions if delays are expected.
Safety Considerations for Taking a Dental Impression
Flammability of Adhesive (Xylene):
Ensure that the adhesive used for the impression tray is stored away from open flames or heat sources, as it may be flammable.
Protective Gear:
Always wear protective gloves and a mask to prevent contamination and exposure to impression materials, which may cause skin irritation or respiratory issues.
Ventilation:
Ensure that the workspace is well-ventilated, particularly when using materials that may emit fumes or odors, to minimize inhalation risks.
Handling Chemicals:
Follow the manufacturer's safety instructions for handling impression materials, including wearing appropriate protective gear and knowing the proper methods for storage and disposal.
Patient Safety:
Ensure the patient is comfortable and aware of the procedure to prevent unexpected movements that may lead to injury.
Keep all equipment, such as instruments and trays, away from the patient’s throat to prevent choking hazards.
Avoiding Cross-Contamination:
Use separate mixing bowls and spatulas for each patient, and sanitize all reusable instruments properly to maintain hygiene.
Immediate Cleanup:
Clean up any spills of impression material promptly to prevent slips and falls in the dental office.
Selecting the Correct Impression Tray Size
Understand Patient Anatomy:
Assess the size and shape of the patient's dental arches and overall mouth dimensions. This can include examining the width of the arch, the height of the palate, and any unique features of the patient's dental anatomy.
Trial Fit:
Before using the impression tray, perform a trial fit in the patient’s mouth.
Ensure that the tray reaches both the anterior (front) and posterior (back) areas of the dental arch without discomfort.
Tray Types:
Be familiar with the different types of trays available:
Standard Trays: Good for general use but may not fit all patients perfectly.
Custom Trays: Made to fit individual patients more accurately when needed.
Partial Trays: Useful in cases where only part of the arch needs to be captured.
Assessment of Comfort:
The selected tray should not impede the patient’s ability to close their mouth comfortably or cause gag reflex. Ensure that the tray offers a snug fit without excessive pressure.
Check for Adequate Coverage:
The tray should adequately cover the entire dental arch to ensure that all relevant structures (teeth, gums, and vestibular areas) are captured in the impression.
Check Tray Cleanliness:
Ensure that the tray is clean, free from debris, and properly prepared before use.
Understand Patient Anatomy:
Assess the size and shape of the patient's dental arches and overall mouth dimensions. This can include examining the width of the arch, the height of the palate, and any unique features of the patient's dental anatomy.
Trial Fit:
Before using the impression tray, perform a trial fit in the patient’s mouth.
Ensure that the tray reaches both the anterior (front) and posterior (back) areas of the dental arch without discomfort.
Tray Types:
Be familiar with the different types of trays available:
Standard Trays: Good for general use but may not fit all patients perfectly.
Custom Trays: Made to fit individual patients more accurately when needed.
Partial Trays: Useful in cases where only part of the arch needs to be captured.
Assessment of Comfort:
The selected tray should not impede the patient’s ability to close their mouth comfortably or cause gag reflex. Ensure that the tray offers a snug fit without excessive pressure.
Check for Adequate Coverage:
The tray should adequately cover the entire dental arch to ensure that all relevant structures (teeth, gums, and vestibular areas) are captured in the impression.
Check Tray Cleanliness:
Ensure that the tray is clean, free from debris, and properly prepared before use.
Applying your Adhesive
Fix should be dispensed into a disposable dappens pot and applied with a disposable brush
Allow to dry for 3 mins
Positioning of the Patient and Dentist When Taking a Lower Impression
Patient Positioning:
The patient should be seated comfortably in an upright position with their head supported.
Ensure that the patient's mouth is at a level that allows easy access for the dentist without straining, typically around the dentist's elbow height.
A dental bib or towel should be used to protect the patient's clothing and absorb any saliva during the procedure.
Use of Dental Chair:
Adjust the dental chair to recline slightly if necessary to allow better visibility and access, especially to the posterior teeth.
Make sure the chair provides adequate back support for the patient, keeping them relaxed.
Dentist Positioning:
The dentist should stand or sit at a comfortable height where they can maintain good posture while taking the impression.
Ideally, the dentist should position themselves directly in front of the patient for taking a lower impression to have a full view of the dental arch being captured.
The dentist should minimize reaching across the patient's body to avoid discomfort for both the dentist and patient.
Instruments Accessibility:
Keep all necessary instruments and materials within close reach to avoid unnecessary movement during the procedure.
Communication:
Clearly communicate with the patient before starting the impression.
Positioning the patient comfortably and assuring them of the steps can help make the impression process smoother and reduce anxiety.
Positioning of the Patient and Dentist When Taking an Upper Impression
Patient Positioning:
The patient should be seated comfortably in an upright position with their head supported.
Ensure that the patient's mouth is at a level that allows easy access for the dentist without straining, typically around the dentist's elbow height.
A dental bib or towel should be used to protect the patient's clothing and absorb any saliva during the procedure.
Use of Dental Chair:
Adjust the dental chair to recline slightly if necessary to allow better visibility and access to the upper dental arch.
Ensure the chair provides adequate back support for the patient, keeping them relaxed.
Dentist Positioning:
The dentist should stand or sit at a comfortable height, preferably directly behind of the patient.
The dentist should be positioned at a height that allows for proper ergonomics to avoid strain.
Instruments Accessibility:
Keep all necessary instruments and materials within close reach to avoid unnecessary movement during the procedure, allowing for a smoother process.
Communication:
Clearly communicate with the patient about the procedure before beginning.
Assuring the patient of the steps being taken can help reduce anxiety and promote comfort during the impression-taking process.
Measuring and Mixing Alginate for Dental Impressions
Prepare Materials:
Gather all necessary materials, including alginate powder, water, a mixing bowl, a spatula, and measuring cups.
Determine Measurement Ratios:
Refer to the manufacturer's instructions on the alginate packaging to determine the correct powder-to-water ratio. Standard ratios often range between 1:1 to 1:2, depending on the desired consistency (higher water for a softer mix, less for a firmer mix).
Measure the Alginate Powder:
Use a measuring scoop or cup to measure the required amount of alginate powder. Ensure it is leveled off to avoid over or under-measuring.
Measure the Water:
In a separate measuring cup, measure the corresponding amount of water as per the determined ratio.
Mixing Process:
Pour the water into the mixing bowl first, followed by adding the measured alginate powder.
Using the spatula, start mixing the material together, incorporating the powder with the water.
Use a vigorous folding motion to combine the ingredients evenly until a smooth, homogenous consistency is achieved with no lumps.
Time Management:
Mix the alginate quickly to prevent it from beginning to set prematurely, ensuring the impression can be taken in a timely manner.
Consistency Check:
The final mix should be creamy and smooth, easily adaptable to fill the impression tray without running or being too stiff. Adjust the mix by adding small amounts of water or powder if necessary to achieve the desired consistency before loading the tray.
Loading the Impression Tray:
Once the alginate is mixed properly, it should be loaded into the impression tray promptly to maintain the material's setting time and effectiveness.
Equipment for Alginate Impressions
Impression Tray:
An appropriate size for the patient's dental arch, which may be standard or custom.
Alginate Powder:
The main material used for making the impression.
Water:
Used to mix with alginate powder at the correct ratio.
Mixing Bowl:
A container used to mix alginate powder and water.
Spatula:
A tool for mixing the alginate to a smooth, homogenous consistency.
Measuring Cups:
For accurately measuring alginate powder and water in the proper ratio.
Protective Gloves:
To maintain hygiene and protect the dentist's hands from the impression material.
Mask:
To prevent inhalation of any dust from the alginate powder during mixing.
Paper Towels:
For cleanup purposes after the impression process.
Dappens Pot:
A disposable container for dispensing adhesive if needed for the impression tray.
Disinfectant
A spray of disinfectant for the storage of the impression tray.
How to Take Primary Impressions
Prepare Necessary Materials:
Impression tray (appropriate size)
Impression material (alginate)
Mixing bowl and spatula
Measuring cups for powder and water
Protective gloves and mask
Paper towels for cleanup
Select the Appropriate Tray:
Choose a tray that fits comfortably in the patient's mouth and adequately covers the dental arches.
Ensure the tray is clean and free from any debris.
Measure and Mix Alginate:
Refer to the manufacturer's instructions for the correct powder-to-water ratio (usually 1:1 to 1:2).
Measure the alginate powder and water separately using measuring cups.
Pour the water into the mixing bowl first, then add the alginate powder.
Use a spatula to mix the materials until a smooth, lump-free consistency is achieved.
Load the Impression Tray:
Fill the chosen impression tray with the mixed alginate using a spatula.
Ensure the tray is filled evenly and adequately without any air bubbles.
Prepare the Patient:
Explain the procedure to the patient to help them feel comfortable.
Protect the patient's clothing with a dental bib or towel.
Insert the Tray:
Gently insert the loaded impression tray into the patient's mouth, ensuring proper positioning over the dental arch.
Press down firmly but gently to make adequate contact with the gums and teeth.
Instruct the Patient to Bite Down:
Ask the patient to gently close their mouth to allow the impression material to capture the necessary structures.
Keep the tray steady and avoid any movement during the specified setting time (refer to manufacturer's instructions).
Remove the Tray:
Once the alginate has set (usually within a few minutes), gently rock the tray back and forth to break the seal before removal.
Carefully take the tray out of the patient's mouth.
Inspect the Impression:
Check the impression for accuracy to ensure that all teeth, gums, and vestibular areas are captured.
Look for any voids or air bubbles that may compromise the impression quality.
Clean Up:
Rinse the impression with water to remove saliva and maintain hygiene protocols.
Clean the impression tray and dispose of any used materials properly.
How to Cast Impressions
Prepare Necessary Materials:
Alginate impression
Dental stone or plaster
Mixing bowl and spatula
Measuring cups and scale
Water
Vibrator (optional)
Protective gloves
Paper towels for cleanup
Select the Right Type of Stone:
Choose the appropriate casting material. Dental stone is typically preferred for more accurate and durable casts, while plaster may be used for preliminary models.
Measure and Mix the Stone:
Refer to the manufacturer's instructions on the package for the correct powder-to-water ratio, usually approximately 1:1.
Measure the water using a measuring cup.
Pour the water into the mixing bowl first, then gradually add the dental stone powder while mixing with a spatula.
Mix until a smooth, lump-free consistency is achieved. Ensure to whisk quickly to reduce the incorporation of air.
Load the Impression:
Ensure the alginate impression is clean and free from saliva.
Carefully pour the mixed dental stone into the impression tray, ensuring it flows into all spaces to avoid voids.
Use a spatula to help spread the material if necessary.
Vibration:
If available, use a vibrator to gently tap the impression tray to help remove any trapped air bubbles and ensure even distribution of the stone material.
Allow to Set:
Allow the dental stone to set as per the manufacturer's instructions, typically about 30-60 minutes at room temperature.
Remove the Cast from the Impression:
Once set, carefully separate the cast from the alginate impression by gently flexing the impression or rocking it back and forth.
Inspect the Cast:
Check the cast for any flaws or areas that need touching up. Look for complete details of the dental surfaces without voids or inaccuracies.
Clean and Store the Cast:
Rinse the cast with water to remove any residual alginate.
Store the cast in a dry, clean area. If needed, apply a sealant or stone hardener for added durability before storage.
Cleanup:
Clean all mixing equipment and the workspace to maintain hygiene and prevent cross-contamination.
How to Improve Patient Comfort During Impressions
Communicate Clearly:
Explain the procedure to the patient in detail beforehand to alleviate any anxiety. This can help the patient feel more in control and comfortable.
Use of Breathing Techniques:
Encourage the patient to breathe through their nose instead of their mouth. This can help them feel more relaxed and reduce the likelihood of gagging.
Suggest slow, deep breaths to help calm the patient and maintain focus.
Proper Patient Positioning:
Ensure the patient is seated comfortably with their head and neck well-supported. A comfortable chair can help relax the patient.
Adjust the dental chair to an appropriate height for easy access, reducing strain on both the patient and dentist.
Use of Dental Bibs or Towels:
Place a dental bib or towel over the patient’s clothing to absorb saliva and protect their clothes, which helps reduce anxiety about mess.
Minimise Discomfort:
Select the appropriate size impression tray that properly fits the patient's mouth to prevent discomfort or pressure points.
Always check that the trays are clean and properly prepared prior to use.
Custom Accessories:
For patients with a strong gag reflex, consider using a smaller sized tray or design tailored for better comfort.
The use of topical anesthetics may also help mitigate discomfort for sensitive areas.
Distraction Techniques:
Offer distractions during the process, such as listening to music or using a video display to keep the patient engaged and less focused on the procedure.
Taking Breaks:
If the patient feels uncomfortable, encourage them to signal if they need a break during the impression-taking process. This can help manage their comfort levels.
Preventing Gag Reflex:
Avoid overloading the impression tray with material, which can trigger gagging. Be mindful of the amount used.
Allow the patient to taste the material before application, if possible, to familiarise them and reduce surprise.
Advise the patient to keep their chin slightly downwards
Seat the posterior part of the tray first
Post-Procedure Care:
After taking the impression, provide reassurance and comfort during the removal of the tray, using a gentle technique to ease any discomfort.
Checking your Impression
Impression tray should not be visible through the alginate
All teeth should be included in the impression
There should be no air bubbles
No tearing or dragging of the material
Impression material should not have come away from the tray
Disinfecting Your Impression
Perform is an oxygen-based concentrate in powder form which is used to disinfect medical devices such as impressions
Green box
Completing Your Lab Card
Attach patient ID
Disinfect all contaminated items in Perform and print your name to confirm disinfection
Write what the next stage is
Write the date of the next appointment (allow 14 days)
Sign your name against what you’ve done
Complete all details
Add additional information when required
Preparing to Send Impressions
After removing from Perform (10 mins), rinse the impression
Wrap in a clean damp gauze (alginate will distort if dried out)
Place impressions in a clear polyethene bag and seal
Apply a patirnt stciker to the bag
The impressions and lab card get taken to the lab