 A loose implant-retained denture is not always solved by fitting stronger retention inserts. In many cases, the real problem is the relationship between the denture base, the supporting tissues and the LOCATOR attachments. The tissues continue to change after a denture is fitted. The ridge resorbs, the denture loses support and the prosthesis begins to move during function. The patient may describe this as the LOCATORs “not holding”, but worn inserts may be only part of the problem. If the denture rocks before the attachments engage, fitting stronger inserts can make the denture feel tighter without making it more stable. It may even increase the load around the implants. A useful principle is that approximately 80% of implant overdenture success comes from a correctly designed, well-supported and accurately fitting denture. The attachments provide the remaining 20% of retention. This is not a scientific formula, but it is a very practical way to think about these cases. When the existing aesthetics, tooth position and occlusion are acceptable, a digital copy denture workflow can preserve what already works while providing:
Understanding the correct denture terminology
Clear terminology prevents confusion between the practice and laboratory. The tissue-facing surface of a denture is called the fitting surface or intaglio surface. This is the surface that rests against the oral tissues. The visible external surface of the denture base is usually called the polished surface or cameo surface. It includes:
A proper 360-degree denture scan therefore captures the entire prosthesis, including the teeth, polished surfaces, borders and wash impression on the fitting surface. Scanning only the fitting surface is not sufficient because the laboratory would have no reliable reference for the tooth position, external contours or overall denture form. When is this workflow appropriate? This procedure is particularly useful when the patient likes the existing denture but wants it to fit and retain better. A suitable patient may say:
Check the following before proceeding:
Start by examining the implants and attachment system Do not assume that every low-profile overdenture attachment is a genuine LOCATOR. Different manufacturers use different abutments, housings, processing inserts and retention inserts. Components that appear similar may not be interchangeable. The laboratory needs to know the exact system before ordering or designing around it. Record the following:
Why the wash impression comes before the scan The existing fitting surface represents the denture’s current relationship with the tissues. If the denture has become loose because the ridge has changed, scanning the acrylic alone simply preserves the old, inaccurate fit. A light-bodied elastomeric wash, commonly a light-bodied polyvinyl siloxane material, records the updated tissue surface inside the denture. Once scanned, this wash becomes the new digital fitting surface. Before taking the wash:
Seat the denture using even pressure. If the opposing dentition is reliable, the patient may close gently into the established position, but heavy biting should be avoided. Excessive pressure can displace the tissues and create a denture that fits the compressed impression beautifully but becomes unstable once the tissues rebound. After setting, inspect the wash carefully. The impression should show:
How to complete the 360-degree intraoral scan The denture is normally scanned extraorally using the intraoral scanner. The objective is to create one complete digital file containing the fitting surface, borders, polished surface and teeth. Leave the accepted wash impression inside the denture. Do not remove and reseat it because it may distort, tear or separate from the base. A practical scanning sequence is:
Long, smooth and reflective areas can be difficult for some scanners to track. Move slowly, maintain overlapping scan data and use anatomical landmarks such as teeth, rugae, border contours and impression texture to maintain alignment. Follow the scanner manufacturer’s instructions regarding scan spray, as many current scanners do not require it. Avoid repeatedly scanning the same area from random directions. This can create stitching errors, double surfaces or distorted borders. A controlled path is usually more accurate than enthusiastic digital painting. Do not forget the opposing arch and bite The 360-degree denture scan records the shape of the prosthesis, but it does not necessarily tell the laboratory how that prosthesis relates to the opposing arch. Where applicable, provide:
If the patient wears complete upper and lower dentures, stabilise both dentures during the bite scan. Movement during scanning can create a convincing-looking digital bite that is clinically wrong. What the laboratory does with the scans Once the records arrive, the laboratory imports the denture, opposing arch and bite scans into the digital workflow. At Bremadent, we first assess whether the files contain enough reliable information to reproduce the case. We check the fitting surface, border continuity, tooth anatomy, bite alignment and available space around the planned attachment positions. The existing denture acts as the reference for:
This is one of the most useful features of the workflow. We are not forced to choose between copying the existing denture and improving the fit. We can preserve the features the patient likes while changing the surface that no longer works. Designing the attachment recesses and escape vents The laboratory identifies the approximate position of each LOCATOR abutment and designs open recesses or channels in the new denture base. These recesses must provide enough space for:
An escape or vent hole can also be created from each recess to an accessible surface. This is normally positioned on the lingual side of a lower denture or, where appropriate, towards the palatal aspect of an upper denture. The vent serves several purposes:
Should the new denture be 3D printed or milled? The final prosthesis may be manufactured using a validated 3D-printed denture workflow or milled from pre-polymerised material. Both routes can work well when the design, material, manufacturing process and post-processing are properly controlled. The decision depends on the selected system, available materials, required strength, repairability, turnaround and clinical circumstances. Regardless of how it is manufactured, the laboratory must preserve:
How to carry out the chairside pick-up The final position of the metal housings is best registered intraorally because this records their true relationship to the abutments, tissues and denture at the time of fitting. Always follow the attachment and pick-up material manufacturers’ current instructions. A typical direct pick-up sequence is:
What is the black processing insert? In the conventional LOCATOR system, the black component is called the black processing male. It sits inside the metal denture cap or housing during processing and chairside pick-up. It is not the patient’s final retention insert. Its purpose is to maintain the correct internal space and relationship while the housing is incorporated into the denture. Unlike the standard dual-retention replacement males, the black processing male does not provide the same central internal engagement used for definitive retention. After processing, it is removed and replaced with the appropriate clinical insert. LOCATOR replacement males are available in different colours and retention levels. The precise colours and forces depend on the specific LOCATOR product family. Other attachment systems may use different colours or processing components, so black should not be assumed to mean “processing insert” across every manufacturer. A sensible approach is to begin with the lowest appropriate retention and increase it only if required. Maximum retention is not automatically the best result. Patients with reduced dexterity may struggle to remove an overdenture fitted with inserts that are unnecessarily strong. The traditional laboratory alternative The same clinical objective can be achieved through a conventional analogue workflow. The clinician takes a wash impression inside the existing denture and sends the physical prosthesis to the laboratory. We cast a new model directly into the accepted impression, producing a stone representation of the updated tissues. Depending on the prescription and condition of the denture, the laboratory can then:
This traditional approach remains valuable when the patient does not want any change to the tooth position, aesthetics or established occlusion. It can also be appropriate when the existing denture is structurally sound and the priority is simply a new fitting surface with new attachment components. Its main disadvantage is that the physical denture must usually leave the patient. The digital route also creates a reproducible file that may make future duplication or replacement easier. Common reasons these cases fail Most problems are caused by small errors accumulating across the workflow. The most common avoidable mistakes include:
The final clinical checks Once the pick-up has been completed, assess the denture as a complete prosthesis rather than judging success by how loudly it clicks onto the abutments. Check:
Arrange review according to the clinical situation. A denture can feel excellent immediately after fitting but still require adjustment once the patient has eaten, spoken and removed it several times at home. The practical takeaway A digitally copied implant LOCATOR denture can be an excellent option when the existing teeth, appearance and bite are working but the fitting surface and attachment components are no longer performing properly. The workflow depends on five records and decisions being correct:
Get the denture base right first. Then allow the LOCATORs to do what they are designed to do: provide controlled, maintainable retention rather than carry the entire prosthesis. We provide a trusted laboratory service delivering consistent quality, saving chairside time, and supporting predictable patient outcomes. I am good at eating food but I am not Michelin Chef, If you still don't feel confident in doing them, give us a call and when we can do the pickup for your chair side! 📞: 0208 520 8528 📧: [email protected] 📍: 25A St James Street, London, E17 7PJ
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Private Dental Laboratory in London
 Kash Qureshi - Managing Director, Clinical Dental Technician
About the author:
Kash Qureshi is a Clinical Dental Technician (Denturist) in the U.K who oversees and quality controls over 3000+ fixed and removable prosthesis including implant cases from a clinical and technical aspect monthly at Bremadent Dental Laboratory & Swissedent Denture Clinic in London. www.swissedent.co.uk www.bremadent.co.uk [email protected] Categories
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