The event of the year, I attended another Dentinal Tubules Congress at the beginning of October. The first day of the congress was a full day workshop and I attended a full day on Complete Dentures with Riaz Yar. The day was fantastic, and here is what I learnt...
Assessment
- Be cautious of providing horseshoe shaped upper complete dentures - these increase the rate of resorption of the alveolar ridge over time, as you are not using the palate to support the denture which is the area which usually provides primary support
- Extension of the lower denture onto the retromolar pad areas stops the denture from being displaced distally, therefore if it not extended in this area, the denture will move and cause rubbing. Therefore when considering extensions, extend the denture onto at least the anterior portion of the retromolar pad
- Teeth position in the lower arch much be on the ridge of the mandible, whereas for the upper arch, tooth position tends to be more buccal and labial as a result of the ridge being resorbed width-way. This can lead to a cross-bite at try in stage, but this might be unavoidable as you need to follow the pattern of the patient's ridge
- To assess extensions, do a tipping test at different places in the denture which will tell you where the denture is underextended if the denture is displaced e.g. at incisors, canines, premolar areas
Primary Impressions
Material to use: Compound or stiff alginate
Aim of impression: To capture all soft tissues, pushing muscle attachments of out the way
Lab prescription: Mark extensions on the impression 2mm short of the sulcus.
*Top tip* if you are using compound, mix your compound in with vaseline to make a smoother mix
Secondary Impressions
Material to use: Runny alginate, zinc oxide eugenol or light bodied silicone. Note what material you chose you must request appropriately special care. Alginate = 3mm, others = no spacing. Use greenstick (as pictured above) to recreate this spacing and at the postdam
Aim of impression: to create fitting surface of denture
Lab prescription: Request Manchester lower rim to help you stabilise and permanent bases to test retention - you can always do a wash impression in the permanent base at try in if needed
*Top tip* do not ask for perforated trays, as you can then test the retention of what the final denture will be. Request stub handles to help stabilise and stop the handles getting in the way.
*Top tip* seat impressions from posterior to anterior to prevent any material escaping posteriorly which would cause the patient to gag
Bite Registration
- Get the upper block into the right shape first: lip support, occlusal plane, interpupillary line, buccal corridors
- Once you are happy, move onto the lower rim, check for even occlusion, tooth position
- Check for OVD, ensuring freeway space is 2-4mm. To check there is enough freeway space
- Register using bite registration paste, and mark smile line, canine lines and midline
- Pick tooth mould and shade. Previous dentures or pictures of the patient when they were dentate are useful for this. Ask the lab to leave the 7s off
- Cut the post dam on the master cast 1mm in front of the junction between the hard and soft palate. 1mm in depth with a lacron
*Top tip* to help with planes such as interpupilliary lines or alar tragal lines, you can use some talcum powder on floss to mark onto the patient
*Top tip* if you are unsure of bite registration or having difficulty, ask the lab to only set up the anterior teeth and re-register at try in
Try-In
Check the following:
- Smile line
- Aesthetics
- Occlusion
- OVD
- Sufficient post dam
- Occlusion
- Retention and stability - ask the patient to move their lips/tongue, smile wide etc to check this
*Top tip* for patients who are Afro-Caribbean or have darker pigmentation, instead of pink acrylic you can ask for translucent.
Fit
- Dentures will tighten over the first few days of wear as they bed in
- If there are high occlusal spots, you can ask your patient to grind pumice mixed with toothpaste which will get rid of them
Instructions for patients:
- Dentures will increase salivary flow
- Expect some sore spots
- The denture will move
- Advise fixative when needed - the best on the market is Secure.
- Speech will be affected but should adapt
Trouble shooting
Pain on wearing dentures - always check the occlusal surfaces first before the fitting surface as pain symptoms on eating are the same.
Denture Stomatitis - this can be caused by poor denture hygiene, an ill-fitting denture, a high sugar intake or because of medical issues. Make sure you identify the cause when treating cases
Looseness - if this is during the day, check occlusion as this is due to bruxism during the day. You can use a material such as Viscogel to reline (which also can have nystatin in it) and use a long term functional impression. This will last around 6 weeks, use a closed mouth impression technique and heat the scalpel to remove any excess
What tips do you have for complete dentures? Please leave them in the comments below
