The procedures can be used to take your preliminary impression, this guide is mainly for a S/T Secondary impression. Ask your laboratory to design the S/T like this:
- S/T, no perforations, tissue stops X3 evenly spaced, 1 – 2 mm away from the periphery.
- Single sheet thickness, handle shaped like an F rather than a stump (like the loch ness).
- Retract lips and cheek from the opposite side to your working hand.
- Rotate tray into the same side as your working hand.
- Move labial. Relax pt by asking to close together slightly.
- Seat and check extension around peripheral areas and make sure its not impinging on tissues or muscle attachments.
- Now check path of insertion.
- Check impression material for working time and setting time, this is crucial.
- Add silicone adhesive around peripheral extension of tray, use a heavy viscosity PVS material around this area (1 – 2 mm in height and 1 – 2 mm in width).
- Stand behind patient and place the tray in the mouth exactly as above.
- Change hands over from your working fingers to your other hand.
- Keep the fingers stationary on each side of the crest to maintain stability whilst preforming border moulding.
- Grasp the philtrum and gently squeeze and pull down. (Anterior frenum)
- Push the labial lips downwards then ask the patient to try and blow a kiss. (Anterior vestibular sulcus)
- Ask the patient to slightly close together and grasp one corner of the mouth and pull outwards and downwards X2 and then on the opposing side. (Buccal frenum & vestibular sulcus)
- Ask the patient to open wide and move there lower jaw from side to side. ( Post – zygomatic vestibular sulcus and hamular notch).
- Ask the patent to cough slightly if the patient can tolerate this. ( Function of hard/ soft junction – post palatal zone).
- Stand in front of the patient, change hands from working hands to non, keep two fingers on the tray and thumb positioned under the chin to maintain stability.
- Ask the patient to push their tongue outwards to you, side to side and the top of the mouth do this smoothly and not quickly. (Mylohyoid zone)
- Grasp the lower lip and pull upwards. (Labial Frenum, anterior vestibular sulcus)
- With the fingers positioned correctly ask the patient to blow a kiss. (Anterior, buccal vestibular sulcus).
- Ask the patient to slightly close together and grasp one corner of the mouth and pull outwards and upwards X2 and then on the opposing side. (Buccal Frenum, External oblique vestibular sulcus).
Because it outlines the 3D detailed space of the point of reflection between the cheek muscles and the alveolar bone. It outlines the ideal and optimum peripheral extension to stop over extended dentures causing dislodgement via cheek muscles pushing on the dentures during functional movements. Example time, place your finger in the top part of your buccal vestibular sulcus, now with your lips push down, exactly, need I say no more.
Can I use a special tray extended to that area and just take a final wash?
No. Special trays are rigid and tough and if extended to the maximum depth of the sulcus it will not allow material to flow into this area and will push the cheeks outwards and provide a false representation of the functional movements with all the muscles in a stressed state.
Border moulding needs a material to flow into the peripheral area without stressing the cheek muscles and then set with the simulation of functional movements from the muscles in a relaxed but functional state as preformed in the steps above. This provides a accurate representation of a patient chewing or talking with the dentures borders seating into peripheral area.
Should I do border moulding on all impression, even partials ?
Why not. It allows you to master this and become better with each impression, I do this for all impressions, preliminary, secondary, partially dentate even additions on dentures. It soon becomes second nature and you can become a pro at this. It may seem time consuming at first but think of it like this, you place the tray in the mouth it takes about 1 min 45 seconds for the material to set, border moulding takes just as long. Instead of standing there holding it in place, why not do the border moulding procedure and make effective use of that time spent and make every impression a good first impression.
I will soon continue writing on how to take denture impression like a pro, I am not picky, I am thorough and I like to do things correctly, precisely, productively, consistently and accurately, maybe its the technician in me.
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