Implant overdenture

From implant overdenture parts to implant overdenture cost – Everything anyone wants to know about the implant overdenture!

Implant overdentures come in a variety of styles and are very lab or doctor specific. The popularity of the All on 4 and other implant supported bridges or implant supported dentures have made the implant overdenture much less common, however there are still excellent reasons to recommend an overdenture. There are two reasons that I consider an implant overdenture as a recommendation. First of all, is when a patient has a high smile line and we need to hide the edge of the denture but maintain cleansability. Second would be for a patient with extreme bone loss that needs lip support, cancer rehabilitations and accident rehabilitations are examples.

This page has some rather in depth material and is not easy for the non-dental professional to absorb. If you are a patient you might be better checking out my Implant Supported Dentures page.

Implant Overdenture prosthesis options and nomenclature

  1. Implant Supported Overdenture is also known as an Implant-Supported Bar Overdenture

  2. The Implant and Tissue Supported Overdenture is also known as an Implant Retained Overdenture (Prosthesis) and an Implant Retained Tissue Supported Overdenture

  3. Telescopic Overdenture could be either of the above but it is more likely to be # 2

Implant Supported Overdenture

Implant Supported Overdenture is 4-6 implants in the anterior with a bar superstructure.  The prosthesis has complete support from the bar.  The suprastructure should be precisely and rigidly adjusted to the milled bar and made of the same alloy.

Implant Supported Overdenture bar
implant overdenture

For mandible use only if there is advanced bone resorption and have 15mm or more restorative space.  Good for high muscle attachments, sensitive mucosa, knife edge ridge, high mylohyoid, and exposed mental nerve or IAN.  The milled bar implant supported overdenture presents lower prosthetic complication rates and needs less maintenance then the implant retained overdenture.

Implant and Tissue Supported Overdenture or Implant retained overdenture

Implant and Tissue Supported Overdenture is a patient removable prosthesis that gets support from both dental implants and patient tissue. I prefer the term implant retained denture. It has either a bar or studs on the implants.  Requires fewer implants than any other option.  Ensure if bar with clips only one as multiple inadvertently creates a supported prosthesis.

Codes for implant overdentures

For mandible 2 with bar is best and clip with intimate contact OR 2 individual and want lateral throat form

Best location for 2 implant mand OD is in lateral incisor area with short attachments

Some reinforce acrylic with metal mesh to reduce acrylic fractures. 4 is minimum in maxilla with no palatal coverage but full tuberosity coverage. JOMI 2007 Cavallaro Tarnow  4 to 6 spinted with a bar is the standard for the maxilla but some do free standing dentures. 2 implants then denture works just like traditional denture.  Great for max. when lip support required.

Need to know interocclusal space to know what options available and if need alveoloplasty at time of surgery, need to open vertical (if possible), and/or opposing arch reduction on supra-erupted teeth such as this,

implant overdenture vertical space
Lower teeth supra-erupted resulting in limited space for prosthesis

Attachment options for an implant overdenture are found in the link.

Classification for the implant overdenture

Classification system of the available vertical space can be used to help decide types of treatment.  Measurements are from soft tissue crest to the proposed occlusal plane.

  1. Class I arch has 15mm or greater
  2. Class II arch has 12-14mm
  3. A Class III arch has 9-11mm
  4. Class IV arch has <9mm

Minimum requirement vertically is about 10mm with an ideal breakdown of 2mm for tissue, 2mm for denture acrylic base, 3mm for denture teeth, and 3.35mm for a locator.  For horizontal space constraints a Micro-ERA is 4.43mm so 8mm total is minimum, that leaves 2mm acrylic both sides. For a locator overdenture you need about 9mm vertical and horizontal, but would like to see 10-12mm Lee 2006 JPD Sadowsky 2007 JPD

For bar supported overdenture 13 to 14mm vertical from implant platform to incisal edge is ideal and the space should span <18mm. Use a 2mm vertical stiffener if gets closer to 18mm.  The bar needs 2-4mm vertically and an additional 1-2mm from mucosa to base for hygiene. Clips need 10-12mm in between each implant. A distal extension can go 12mm.  If implant spacing or number of implants is unfavorable then do a bar overdenture and get some tissue support to help. Much of this is from Sadowsky 2007 JPD article.

How to measure vertical space for an implant overdenture.

To measure the space available we have 3 main options

  1. Make radiographic template (code 6190) and have them wear during CBCT
  2. Measure existing/new denture or area with boley gauge, this method is the least diagnostic.
  3. Matrix capture of denture teeth, if not doing CBCT then this is best method.

CBCT option 

This is a double scan technique.  One in which they are first scanned wearing the prosthesis and then the prosthesis is scanned by itself.

  1. If patient is edentulous then make a duplicate of the finished temporary prosthesis with to wear as a radiographic template.
  2. If patient has some teeth remaining do same thing, just remove the teeth that are still present from the duplicated finished temporary prosthesis
  3. To make the radiographic template use 1:3 ratio barium sulfate powder (Hypaque Sodium by Amersham Health) OR
  4. #6 round but to 1/2 depth around the lingual flange and fill with gp and polish off with rubber OR
  5. Add radioopaque glass beads
  6. Can mark attached tissue like seen in A Technique to Identify Attached Gingiva During Virtual Implant Planning
  7. Patient wears during CBCT and besides reading bone levels can measure space available.

Matrix option

  1. Once have approved wax baseplates can just remove from mounted models and measure.
  2. There is several much more complex Aug 10ways to do this but I don’t see how they are a whole lot more informative.

 

Reference

Treatment planning of the implant overdenture

Implant supported overdenture is very similar to the implant supported prosthesis

  • Just follow those steps

Implant retained overdenture is very similar to denture and a fixed detachable provisional

 Implant overdenture procedure in a step by step format

Steps for the initial impression for the implant overdenture

  1. Measure depth from implant platform to most coronal aspect of surrounding gingival tissue for depth locators
  2. Take alginate impression

Steps for the final impressions for the implant overdenture

  1. Seat locator abutments to specified torque
  2. Place implant impression copings
  3. Clear thermoplastic tray by Massad or custom tray
  4. Paint tray with PVS adhesive
  5. Rigid PVS on palate, tissue areas, and directly over implant copings to act as stops.
  6. Trim most away most material except for solid stops on palate, tissue both sides, and on copings.  Leave just enough for positive seat of copings, do not come up sides.
  7. Med PVS on periphery and light inside border mold.
  8. Ask for processed denture base with metal subframe mesh support (probably? some say rather no and let acrylic break before implant does) with holes to pick up locators exactly.
  9. Also want wax rim with central SR Phonares set in wax
  10. Follow denture thread instructions from here

Steps if picking up overdenture intra-orally

  1. Place locator block out spacer ring and then titanium cap with black processing male (1 at a time? 2 at a time? just not all)
  2. Ensure locators with metal housing not hitting
  3. GC fit check
  4. Adjust as needed and then place undercuts with #8 bur
  5. Place vent hole to palatal or lingual
  6. Refine occlusion now
  7. Adhesive painted on denture area
  8. Petroleum jelly in areas don’t want maybe
  9. Block out undercuts on implant (if any) with silicone like fit check or Fit Test C&B VOCO
  10. Place resin in hole and seat denture  self cure or LC if can
  11. Have the patient feel their masseter with their hands as they close and then clench and repeat until they can tell when the muscle is starting to clench.  Tell them you want them to close but not clench at all when doing your reline.
  12. Remove and fill small voids with LC resin
  13. Remove processing male insert and place appropriate strength

Implant overdenture laboratory

Thomas Wade CDT  reference for lab work

Green Dental Lab made nice OD here

Implant overdenture loading and other instructions

Early loading of the implant overdenture is anytime we load between 48 hours and 3 months. Loading lower unsplinted implants at 1 week has same results as at 6 weeks with 14mm implants and a flapless surgery. While still healing recommend a soft diet and removal at night with thorough oral hygiene instructions. Should fabricate a night guard for removable overdentures in order to protect abutments from any para-functional activity.

Implant overdenture complications

Implant overdentures have the highest complication rate of all implant prosthesis.

  • Retention issues 30%
  • Relines needed 19%
  • Attachment fractures 17%
  • Prosthesis fracture 12%
  • Maxilla failure rate of 19%
  • Mandible failure rate only 4%

 

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