Treatment planning

external view dental implant

Treatment planning Implant Supported Prosthesis

First in series of 17 posts on this topic  -->Second post

4 main options for implant supported prosthesis

  1. Fixed ceramometal prosthesis
  2. Fixed detachable prosthesis
  3. Overdenture prosthesis
  4. Fixed removable prosthesis

1. Fixed ceramometal prosthesis=Fixed full arch implant bridges

Cemented crowns on transmucosal abutments OR secured with screws directly into multi-unit abutments.  Basically these are crown and bridge on implants full mouth rehab.  Also could be Ti or Zi substructure with porcelain veneer/overlay Jan 08.  

Requires 6-8 implants min., AP spread of 20mm, 2nd premolar area gets 10mm implant, must have only minor bone loss (especially in anterior esthetic areas).  Must have contingency removable option presented.

Contraindicated for class III patients (if trying to correct), those needing major lip support, and those with moderate to severe bone loss.

6-8 months in temporaries.  Costs the most and loss of individual implant could be detrimental.

Case gummy smile April 12 JPD steps

2. Fixed detachable prosthesis=Fixed full-arch bridge on multi-unit abutments=Screw-retained hybrid denture=Implant (Abutment) Supported Fixed Prosthesis=hybrid denture=implant retained fixed denture=All on 4 or AO4.

Some may say the term ISFP is only used for a segmented cemented prosthesis and all the others are fixed AND removable.
Traditionally was denture teeth and acrylic attached to metal framework but some now doing ceramic teeth and pink porcelain or GC Gradia to milled framework of Zi or Ti.

“Full wrap” has acrylic or porcelain on under side
“Montreal” has polished metal on tissue side

Vertical clearance, also known as restorative space, for a hybrid denture

The number seen most often is 15mm. This is from the top of the implant to the incisal edge. This is not necessarily the same as saying top of the implant to the occlusal plane. When one restores to the normal 2-4 mm of overbite, this means the posterior restorative space is 2-4 less than the anterior. Thus making the posterior more in the 11-13mm range. Furthermore, these numbers assume acrylic metal prosthesis.

Hybrid denture clearance
Hybrid denture vertical requirements for prosthesis only. This can be less by dropping the 2mm acrylic on the bottom and just having metal and by using zirconia instead of acrylic.

AP spread is very important to these cases.

My opinion is there should be 2 separate AP spread calculators, one AP spread for each side. The exact definition or calculation is irrelevant though as exactly what AP spread multiplier a patient can have is a case by case determination. In genreal more spread is better but how much is needed for a given case is not something you can really determine. Numbers in research span from 1 to 2.5x AP spread to 15-20mms. Walter JADA 2020

Requires 4-5 implants min., 1.5 AP spread x=10mm to get PM and molar cantilever, group function.

How measure AP center of anterior to line connecting distal edge of posterior implants on both sides.  Also think Kent Knoernschild in lecture did anterior front implant to line connecting middle of posterior implants
AP spread can vary as shown in this image.
The AP spread can vary from left and right side.

This video shows me measuring AP spread on a model.

Phonetic issues with max in 1/3 cases and 10% at 1 year still.  Flanges can be unhygienic.  Unesthetic in max if little ridge resorption and/or higher lip line.  Mand. can have cheek biting and not enough facial scaffolding.  Shouldn’t do on lower if upper is just denture.Wear and breaking teeth major issues when in acrylic.

 Hybrid Prosthesis Codes

  1. D6114 – implant /abutment supported fixed denture for edentulous arch – maxillary
  2. D6115 – implant /abutment supported fixed denture for edentulous arch – mandibular
  3. D6116 – implant /abutment supported fixed denture for partially edentulous arch – maxillary
  4. D6117 – implant /abutment supported fixed denture for partially edentulous arch – mandibular
  1. Semi-precision attachment (multi-unit) 6052


3. Overdenture prosthesis 

  1. Implant Supported Overdenture
  2. Implant and Tissue Supported Overdenture=Implant Retained Overdenture
  3. Telescopic could be either or the above but more likely to be #2


  1. Bar 6055
  2. D6110 – implant /abutment supported removable denture for edentulous arch – max
  3. D6111 – implant / abutment supported removable denture for edentulous arch -mandibular
  4. D6112 – implant /abutment supported removable denture for partially edentulous arch – maxillary
  5. D6113 – implant /abutment supported removable denture for partially edentulous arch – mandibular

      3a Implant Supported Overdenture is 4-6 implants in the anterior with bar superstructure.  Completely supported by bar.  The suprastructure is recommended to be precisely and rigidly adjusted to the milled bar and made of the same alloy.

“Free shaped milled bar” is a rectangular bar with 0-10 degrees taper in 2 degree increments
“Paris” bar = Montreal style bar modified to accept attachements

For mand. only with advanced bone resorption 15mm or more restorative space (maybe not quite that much in posterior).  Good for high muscle attachments, sensitive mucosa, knife edge ridge, high mylohyoid, exposed mental nerve or IAN.

3b Implant and Tissue Supported Overdenture is either bar or studs on implants and prosthesis gets some support from tissue also.  Requires fewer implants than any other option.

Some reinforce acrylic with metal mesh to reduce acrylic fractures. 4 is min. in maxilla with no palatal coverage but full tuberosity coverage.  2 implants then denture looks just like traditional denture.  Great for max. when lip support required.

The milled bar implant supported overdenture presents lower prosthetic complication rates and needs less maintenance then the implant retained overdenture.

Classification system for OD May 11 of the vertical space an be used to help decide types of treatment.  Measurements from soft tissue crest to proposed occlusal plane.

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

Min. requirements 10mm ideal breakdown is about=vertical 2mm tissue, 2mm denture acrylic base, 3mm for denture teeth,
3.35mm for locator.  For horizontal space constraints (in mandible) Micro-ERA is 4.43mm so 8mm total is min. (2mm acrylic both sides)
For locator overdenture need about 9mm vertical and horizontal, but would like to see 10-12mm Lee 2006 JPD Sadowsky 2007 JPD
For bar supported overdenture 13-14mm vertical platform to incisal edge(bar needs 2-4mm plus 1-2mm space for hygiene and then locator) June 07
Span <18mm with 2mm vertical stiffener.  Clips need 10-12mm in between each implant June 07
Bar needs 2mm from mucosa to base bar.  Distal extension can go 12mm.  If implant spacing or number unfavorable then do bar overdenture and get some tissue support to help

4. Fixed Removable Prosthesis=Marius Bridge=Patient Removable Fixed Bridge is similar to implant supported overdenture but is more secure.

Consists of a meso-bar=primary bar and a superstructure.  Superstructure attaches to fixed meso-bar with 3 frictional pins and 2 posterior swivel attachments and is also precision milled for frictional retention at 2 degrees.  5 implants min.

Meso-bar must be at least 4mm tall.  Very expensive, very technique sensitive, and requires patient dexterity.  Only useful for patients with extensive bone resorption but that refuse to have any type of overdenture that have the dexterity to remove.  According to Nader Sharifi only 5 US labs can make.

Maxilla treatment planning

  1. If there is very little bone resorption then a fixed ceramometal prosthesis if can meet the requirements of 6 implants, 20mm AP spread, and 10mm implant in 2nd premolar (this is very outdated for 2023).
  2. If moderate or more bone resorption than fixed detachable (such as an all on x). As long as can get lip support, can deal with speech issues, and the patient does not have a super high lip line.  A really high lip line or smile line can rule out the fixed detachable, all other choices are better options for this person.  Implant and tissue supported is option, if the patient is fine with something removable and is fine with still getting a minimum of 4 dental implantsDi Francesco IJP 2019 shows in a systemic review that splinting and not splinting of 4 implants did not impact longevity, implant survival, or patient satisfaction. Fixed removable is good but expensive and tough to do.
  3. Main deciding factors for fixed versus removable is how lingual/palatal is the bone and the maxilla-mandibular relationship. Occlusal issues – can make Class III.  Soft tissue support issues – lip and cheeks.

Surgical options for gingival display Nov 12

  1. Ostectomy with saw or chisel for mild to moderate gingival display.  Must have enough space beneath sinus or nasal floor
  2. Lefort I (yeah right)
  3. Ortho intrusion if just anterior supra-erupted
  4. Plastic surgery ie lip repositioning for hyper-mobile lip or botox
  5. Just do an overdenture or denture.


  1. If little bone resorption then Fixed ceramometal if meet requirements 6 implants, 20mm AP spread, 10mm implant in 2nd premolar.
  2. If moderate or more bone resorption than fixed detachable is very good choice as are the overdenture options if OK with removable.  Be careful what this occludes against though ie maxilla denture and maxilla will get destroyed.
Something for the patient to think about

Very similar to denture planning.  Make wax trial denture. Remove flange to see if need that support or not.

Is the patient a bruxer and what will prosthesis be opposing?
Use group function and use heavy anterior guidance

Need to level opposing arch.

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,

Lower teeth supra-erupted resulting in limited space for prosthesis

10-11 mm from soft tissue to occlusal plane can do traditional fixed implant crowns (3mm of soft tissue to bone assumed)
11-15mm implant supported fixed prosthesis.  Need more in anterior than in posterior.  Need more if acrylic (=15mm ideal) then if zirconia (=10-12mm is adequate) or ceramics.  The 10-12mm for zirconia starts to become an esthetic issue in the anterior as we are talking about 7-9mm for teeth which is pretty short.
Greater than 15mm becomes an issue if fixed start thinking removable with bar

If implant spacing or number unfavorable then do bar overdenture to get some tissue support to help

To measure the space available 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 (least diagnostic)
  3. Matrix capture of denture teeth (if not doing CBCT then this)

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.


  1. Implants placed and immediate screw-retained (SR) temporary prosthesis
  2. Implants placed and existing denture converted to SR temp prosthesis (Prob never do this way)
  3. Implants placed and immediate denture delivered
  4. Implants placed and existing denture relined

For options #3 and #4 both the implant or mutli-unit abutment should have healing cap if no SR temporary prosthesis.

Find esthetic A point.  Measure distance from ridge with Massad tool
Check where that point is with high smile (gummy smile?)

Return for wax try-in with to without teeth depending on if they had previous or not

Surgical considerations

  1. 6-8 months post bone graft can place implants
  2. 6 months after implants placed can take final impressions