Overdentures

Dr Clarisse Ng

Overdentures

• a removable partial or complete denture that covers and rests on one or more remaining natural teeth, roots, and/or dental implants

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Why use an overdenture?

• Extraction of entire dentitions resulted in residual ridge resorption. Occlusal forces of functional and parafunctional nature exert an adverse influence on the denture supporting tissues.

• By retaining teeth, the treatment strategy is to share stress concentration between abutment teeth and denture supporting tissues.

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Advantages

• Maintenance of more residual ridge integrity. This results from improved stress distribution

• Denture stability and retention can be enhanced.• “Natural feeling” – better occlusal awareness, biting force,

neuromuscular control• Viable and simple alternative to complete denture• Application is virtually unlimited

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Disadvantages

• Patient’s lack of oral hygiene motivation• Covered abutments are not conducive for maintaining a

plaque free environment. • Inadequate space – potential weakness in acrylic resin

denture base

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Indications and treatment planning

• Group 1 – patients with few remaining teeth that may be healthy or periodontally involved, coronally intact or morphologically compromised.

• Treatment is usually straightforwardi. Analysis of articulated diagnostic castsii. Radiographsiii. Determine potential abutment teeth’s restorative

and endodontic requirements

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• Group 2 – patients who are diagnosed with a mutilated or severely compromised dentition.

• Treatment is often defined by complexity, expense and time implications

i. Selected extractions may be carried out – retention of teeth with good alveolar support will preserve bone

ii. Retention of periodontally compromised teeth may affect periodontal status

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Selection of abutment teeth

(1) Periodontal and mobility status- periodontally compromised teeth with horizontal bone loss are suitable- vertical bone loss, coupled with Class 2 or 3 mobility are bad candidates. Slight mobility is not contraindication – favorable change in crown-root ratio after preparation. - circumferential band of attached gingiva (1 mm) is a requirement for abutment selection

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(2) Abutment location- anterior mandibular alveolar ridge appears to be most vulnerable to bone loss. Consider maintaining canines and/or premolars- same in maxilla, although incisors are also used. - clinical experience supports the recommendation of at least one tooth per quadrant. If this recommendation is exceeded, retained teeth should not be adjacent ones to minimize compromise in soft tissue health.

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(3) Endodontic and prosthodontic status- anterior single rooted teeth are easier and less expensive to prepare. - the selected teeth can be reduced for technical convenience and treated with sealant restorations and fluoride applications.

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Summary(1) Abutment tooth must have healthy periodontal tissues(2) Reduction of the coronal portion of tooth to achieve a better

crown-root ratio. Also to create space for placement of denture teeth.

(3) Coverage of the tooth/root – amaglam or composite or gold coping . A simple, short, convex abutment preparation is the optimal root surface preparation. Preparation should taper towards occlusal or incisal surface

(4) Provision of attachment mechanism – intracoronal or extracoronal, resilient or non-resilient

(5) Motivated patient. Fluoride is prescribed for daily application to the inside of the overdenture.

(6) Long term monitoring of abutment teeth

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Gold copings

http://vdc.dentistindia.com/overdenture.asp

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http://vdc.dentistindia.com/overdenture.asp

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Magnets

http://priory.com/mags.htm

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Tissue bar

http://my.clevelandclinic.org/PublishingImages/Dentistry/BarOverdenture.png

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Ball attachment

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Bar and clip in anterior, ERA attachments posterior

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ERA

http://www.crowndentalstudio.com/docpage.cfm?doc_id=107

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Male Color Code:• Black fabrication male• White final male with light retention• Orange final male with moderate retention• Blue oversize male with heavy retention• Grey oversize male with very heavy retention• Yellow extra oversized male with more retention than grey• Red extra oversized male with more retention than yellow

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Standard ERA ERA-RV

Standard ERA 4.0 mm

ERA-RV 3.5 mm

http://www.nationaldentex.com/pdfs/ERA_procdure.pdf

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Locator

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• Stainless Steel Denture Cap with Black Processing Male• White Nylon Male (5lbs),• Pink Medium Retention Nylon Male (3lbs)• Blue Light Retention Male (1.5lbs)• Block-Out Spacer

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• If the divergence of any abutment is between 100 and 200, use the Extended Range Replacement Male which can accommodate a divergent abutment up to 200 (400 between multiple abutments)

• Green – 4 lbs• Orange – 2 lbs• Red – 0.5 lbs

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Low profile

3.17 mm 4.85 mm 5.82 mm 6.14 mm 6.22 mm

Locator ERA Dal-Ro O Ring EDS

http://www.implantlubbock.com/Locator%20attachment.pdf

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Locator tool

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QUESTIONS?