Maxillary Overdentures: What Implant Support is Required?

4 implants in the maxilla should be really a minimum and should be splinted by the means of a bar. Ideally : 6 . Current evidence suggests 4 minimum and splinted are better but remember either way the more implants the more supoort and the more versility if failure of one fixure does occur. i.e if 4 implants are placed a single failure occurs how to you temporise during healing - better to have 6 (centrals,canines, 4`s or 5`s depending on arch width). I use a lab in germany called ruberling Dental Labor that produce swing lock overdentures on a milled bar based on 6 implants in the maxilla - we also have 30 years clinical data published on the technique.

4 to 6 free standing implants should do fine, also partial palatal coverage can me used

4 to 6 implants is fine in the maxilla with free standing abutments. Current research shows that free standing abutments direct fewer forces to the implants. Splinting the implants together does not necessarily make them stronger. If I could figure out how to post the article I would, but here is the information for those that would like to see the article. "Comparison of Load Distribution for Implant Overdenture Attachments" Dr. Vicki Petropoulos, International Journal of Oral & Maxillofacial Implants, Volume 17, Number 5, 2002.

Here is the article from PubMed referenced by Nicholas Varras, CDT PURPOSE: The aim of this study was to compare the force and moment distributions that develop on different implant overdenture attachments when vertical compressive forces are applied to an implant-retained overdenture. MATERIALS AND METHODS: The following attachments were examined: Nobel Biocare bar and clip (NBC), Nobel Biocare standard ball (NSB), Nobel Biocare 2.25-mm-diameter ball (NB2), Zest Anchor Advanced Generation (ZAAG), Sterngold ERA white (SEW), Sterngold ERA orange (SEO), Compliant Keeper System with titanium shims (CK-Ti), Compliant Keeper System with black nitrile 2SR90 sleeve rings (CK-70), and Compliant Keeper System with clear silicone 2SR90 sleeve rings (CK-90). The attachments were tested using custom strain-gauged abutments and 2 Brånemark System implants placed in a test model. Each attachment type had one part embedded in a denture-like housing and the other part (the abutment) screwed into the implants. Compressive static loads of 100 N were applied (1) bilaterally, over the distal midline (DM); (2) unilaterally, over the right implant (RI); (3) unilaterally, over the left implant (LI); and (4) between implants in the mid-anterior region (MA). Both the force and bending moment on each implant were recorded for each loading location and attachment type. Results were analyzed using 2-way analysis of variance and the Duncan multiple-range test. RESULTS: Both loading location and attachment type were statistically significant factors (P < .05). In general, the force and moment on an implant were greater when the load was applied directly over the implant or at MA. DISCUSSION: While not significant at every loading location, the largest implant forces tended to occur with ZAAG attachments; the smallest were found with the SEW, the SEO, the NSB, the CK-70, and the CK-90. Typically, higher moments existed for NBC and ZAAG, while lower moments existed for SEW, SEO, NSB, CK-90, and CK-70. CONCLUSION: For different loading locations, significant differences were found among the different overdenture attachment systems. Int J Oral Maxillofac Implants. 2002 Sep-Oct;17(5):651-62. Comparison of load distribution for implant overdenture attachments. Porter JA Jr, Petropoulos VC, Brunski JB. Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York, USA

Going fixed on maxilla not a good idea. Trying to juggle a good seal for phonetics while still leaving access for hygiene is tough (impossible?).

I do quite a lot of bar over dentures. Most are 4 with a metal reinforced bar overdenture with either Hader/Bredent/or rhine attachments. I have recently tried swing lock attachments that are milled into the bar. The swing lock attachments are very retentive and lock the denture in very well and they are eay to remove causing less worry of pts not being able to remove them once they snap in. The answer to your question is not only on amount of implants but on the width or surface area of the implants. Small diameter implants need more implants for support. The in and out forces and occlussal forces on the bar overdenture has a great bearing on the bone ans surface area of the implants being loaded. So if you are placing all 3.5/10 on the upper, I would place 6-8. wider and longer less. Hope this helps.

Nobody seems to be taking into account what the opposing occlusion looks like. If the patient is fully or partially dentate in the mandible then you need at least 6 implants splinted with a bar. I am totally against free standing implants with locators if the PUD is a horseshoe design. To avoid flexing of the framework you need a palatal strap design. The PUD then looks like a closed oval. This is the only type of design that should be used with free standing implants. In my opinion it is the flexing of the horshoe design that causes the bone loss around the implants. I am reding a case with a bar becuase the restoring dentist didn't listen to me two years ago. Horseshoe shaped denture, six free standing implants with Locators= Bone Loss. Fixed bridgework is a possible Tx option provided that lip support can be achieved by the tooth setup alone. FPD will work in the cases of recent extractions but usually not in the long term edentulous patient. Many times we need to thicken the labial flange to provide necessary lip support. You can't do this with fixed bridgework. You also want the teeth to be set up over the ridge in the fixed option. You can't do this if there is labial resorption of the premaxilla unless of course that the patient agreed to whatever bone and soft tissue grafting was necessary to create the ideal ridge form.

Comments from personal experience: A CT scan should be mandatory to get an idea what the bone is like in the regions where you want to place the implants, especially if you are doing a closed technique ( not opening flaps) The maxillary bone is unpredictable and may not be predictable long term. Immediate loading for conventional size implants should not be a consideration.....leave 4-6 months for integration Mini implants have their own set of rules, and usually work independently of their neighbours.....rarely is a bar is used, and genrally they are loaded immediately.If there is a failure, so little bone loss occurs. At the time of uncovering the implants (conventional size), place healing collars on the implants to allow the soft tissue to heal, relieve the denture that the patient has been wearing and place a soft lining material that will give the CUD more stabilization, but puts very light loads and stress on the newly uncovered implants..... but puts them into the "gradual load mode". Wait a few months following the uncovering stage, and then decide if there will be a bar or individual retainers.... at this point you will be able to track the survival rate,health of each implant, and have a better idea of long term predictability of the implants.The patient is still getting the benefit of implant therapy at this stage, as the healing collars are retained by the tissue conditioner or soft reline material in the relieved hard plastic areas.... so the denture is more secure. I have done all the scenerios, sometimes the results are excellent, other times there are disappointments....always make sure there is a planned solution to be had for a potential failure. Gerald Rudick dds Montreal, Canada

I have done overdentures for years...I am still a big bar fan but have done many numerous with 4 free standing and o ring ataxchments...I ereally don't like the locator idea...this type of case all depends on the patient...size , muscle mass, parafunctional habits...and with four only...I believe you must have some palatal support...if that is not possible then 6 implants with 2 bars for longevity....my opinion after many cases

Depending on the patient's bone volume and density, 4 to 6 or even 8 if the bone is very soft and shallow. Balance them evenly on either side of the maxilla. I have even done with 2 on the canine locations using very long small diameter implants i.e. 2.5mm diameter and 18mm into the bone. Sometimes due to lack of bone on the ridge, I place them along the palatal suture just behind the incisive canal. All cases pertains to oring with housings attached to ballheads. Remember the basic principle of parallelism of all the implants with a range not more than 15 degrees off each other. Immediate loading in most cases. All free standing implants. I do not favour bars because of hygiene and technical problems involved.Keep it simple.

Parallelism is key. If the implants are not parallel, then using an attachment that can correct the divergence of the implants is necessary. Having an attachment that can correct this divergence will preserve the vertical resiliency of the attachments and distribute the forces over the entire edentulous area rather than to the implants alone. I have seen Locator type attachments mentioned. Some, like the ERA can correct for this divergency. Going palateless, I believe, requires the incorporation of a metal framework for the overdenture as well as a palatal strap to provide stability to the hamular notch area.

I have done many,many cases with four maxillary implants and Locators. BUT the implants need to be parallel or close to it, 2 on each side. I do not place a strap across the palate, but I always have a beaded wide metal RPD framework on the midline border of the horseshoe denture - retentive loops that hold onto the acrylic. Impossible to bend or torque. Sufficient acrylic must cover the implant so the attachment housing is covered in processed acrylic. And most important in my opinion, the attachments are picked up with cold cure acrylic ONE AT A TIME with slight occlusal pressure.. GC Fit Checker needs to be used to be sure there is no contact on any metal Locator housing prior to pickup of the Locators(even one contact will act as a fulcrum to break the mucosal seal.) This system takes time to fabricate and deliver, but I've lost no maxillary overdenture implants in 10 years. 4 attachments is very difficult to remove, I think more would be impossible. If there were more, I would leave extras in healing caps as vertical stops only.

There different options that you can use to support Max.Denture. 1. 4 conventional implants: secure denture with o-rings, locators, etc (consider more implants if implants short, small diameter, and soft bone. Then you must consider more implants) 2. 4 conventional implants with bar connected all 4 implant and overdenture 3. The most simple less expensive and in my opinion the best is 6 MDI ( remember you must have good bone support) if you don't then do not even consider that, and use conventional implants with standard surgical protocol. If I have option to place 6 MDI I am happy to that, Its been working excellent and I placed enough of them.

I see some people talking about load, 4 implants in good quality bone should be enough, you don't need to put 6,8,10, or 12 implants to support denture and worry about the the load. This the overdenture its the IMPLANT TISSUE SUPPORTED DENTURE most of the load its on the tissue not on the implants. Its about 80% of load on the tissue. Implant only for retention of the denture.

Is there some way that participants could attach images of their above cases? I would love to have a look at James Soltys cases, particularly how the 'beaded wide metal RPD framework on the midline border of the horseshoe denture' looks

Participants can attach photos via our implant cases section linked to on the menu or available at: http://ddsgadget.com/implantcases/

Dr K Our lab has restored over 100 All-on-4 cases and the discussions that we are having do not take into account the requirements of all-on-4. This technique requires two very important procedures, the placement of the two posterior implants at a 35-45 degree angle and immediate loading of the implants. Paulo Malo and Yvan Fortin along with others have published multiple articles on this and the success rates are amazing (97.4%). As a technician with 20+ yrs of restoring implants I had serious reservations about this procedure but as they say the proof is in the pudding.

To Joe Coursey, Two posterior implants on the maxilla. Where exactly and 35-45 degree angle in relation to each other or to the vertical? Where are the other 2 implants? Are they conventional sized or small diameter implants? And what type of anchoring device? Please can you give details. I find it interesting. Thanks.

Dr K I am a lab owner so you understand my caution in getting to specific but I have participated in several surgery training programs to explain the prosthetic aspect of the procedure. In a nut shell you are placing two implants in a conventional manner in the lateral position these are normally in the 11-13mm range. The two angled implants are in the 15-18mm and must be at least 4mm in diameter and are placed along the sinus wall. The provisional and definitive restorations are screw retained "fixed removables".

Intresting options out there I would like to add Case design is never in isolation of one arch To say you use a particular number of implants to do this type of case i think is to plan with blinkers Is the opposing arch fully dentate... or a slack full denture.... is the patient a bruxist ? Entirely different designs for each case ! Opposing arch ...available bone volume Bone density (its not always D4) Good surgical technique will increase bone density As will good sinus grafting Implant length and width is very important Does you treatment change if you have 4 X 8mm 3.5 diameter Implants VS 4 X 14mm 5.5 diameter??? Intresting as it is to see different options ... like with any comprehensive dental treatment there is no set formula to answer the original question and dicussing treatment options without context can be very misleading.

4 or 6 unsplinted implants, depending upon multiple factors is a published treatment protocol. Cavallaro, JS &amp; Tarnow DP. Unsplinted Implants Retaining Maxillary Overdentures with Partial Palatal Coverage: Report of 5 Consecutive Cases. International Journal of Oral &amp; Maxillofacial Implants Volume 22 Number 5 2007. The Materials &amp; Methods section deliniates the case selection and execution concepts that are critical. Photos as well. Further study is being done. In proper cases, this is a great benefit to select patients.

We are considering a full arch maxilla case as well. Patient is moderate Class III with maxilla underdeveloped in size and buccally resorbed but excellent ridge height and width from cuspid area rearward.(12 x 6 mm implants will fit!)Full opposing dentition. I've seen horseshoe dentures with full cast framework that would seem to be extremely rigid. We may use something like that with ERAs for stabilization. We'll use "More than Four" implants due to occlusal concerns with the Class III, with some implants possibly used for vertical stops only. I'll be reading all the articles suggested to help the doc in working through options. All of your responses have been VERY helpful.

My suggestion would be to read the ITI Treatment Guide Vol 2 titled: Loading Protocols in Implant Dentistry. I think you'll find all the answers there.

Dr.S Sen Gupta, I like the way you see the whole thing..... perfect. I am not a friend of locators, its a matter of cost and less comfort for the patient. If you place 4 locators the patient has a hard time to get it off. 4 implants are enough, if the patient is not a heavy bruxer, the bone density is good, and the angulation is not to extreme ...... what is extreme... the implants are placed thats it. We need to do something.... try to press undo.(in this case..) More is better(6) much more is too much, then you can go with abutments cement-able, or screwed down , always removable. Bar-supported overdentures with ball attachments and galvano give the patients the most secure feeling. You put 4 Attachments for safety, and with a parallel milled bar and the galvano stress-free over the bar you will have enough friction. A small over-frame glued over the galvano (stabilisation)..... you are set. galvano good adjusted gives a perfect fit to the bar, easy to remove for the patient, you load it only with one if you have to..... you can add more if you need to. The 99 % Gold layering gives you a stable friction, and the best thing is the denture looks after years still like new if you show the patient to take care of it. Give your patient a second set, just in case it falls in the sink.... he or she put in the other one , send it to your lab... no stress. If you dont trust this lets add some latches....german construction holds forever.

It doesn't appear that anyone here has experience with (or even knows about) the Marius Bridge. I've been looking at information on the net. The MB is exactly what I'm looking for and I will be seeking an implantologist who can do the job.

If a patient is not a bruxer, if a patient is partial edentulous on the lower then keeping the upper complete denture, placing 4 long parallel implants (canine and second bi regions) is a good service to the patient. Regular 0-rings attachments picked up chairside. Do we always need to go palateless is patients do not need it ? Wouldn't Spark Erosion or Hybrid create difficult hygiene situation ?

Anytime we make a bar or hybrid restoration, then the patient will need to be more meticulous with their hygiene. Free-standing abutments are easier to maintain. If the patient wants or needs a palateless denture, I always use a metal mesh frame as a substructure. I always like to use a palatal strap in the post palatal seal area to lend greater support to the overdenture in the hamular notch area.

Hi, I have been seeing a prosthondontist and OS for almost a year. Started with pain with complete maxilla denture. Had denture x30 yrs. partial on bottom. Pain on rt side(maxilla). Initially thought sinus problem, saw several dentist, then specialist in head neck, all said it is denture related. All going on for about a year. Have had tissue conditioner in since Sept 07.Prosthodontist suggested implant, took measurement said not room, too much bone, need preposthetic surgery, bone shaping,tuberosity reduction, then recommend another denture. recomment implant with bone graft in mandible, right side. One time thought my pain on right maxilla was bite related. Also ?nerve pain, one dentist thought that. Pain is intermittent, throbbing, eating food helps but can't bite on that side(rt). Seeing OS on August 4th for reconsult for prprothetic surgery and possible manidular implants(3) My question, what does not fit mean? How can I have too much bone but need bone grafts (maxilla), and still need prepstothetic surgery to remove bone/tissue. Can they test to make sure it is not nerve, worried surgery could make a nerve problem worse. Thanks, this has been going on about a year Dar

It's unfortunate you are having this pain. We do not always have all the answers. I had a patientS with similar pain about 12 years ago. You may have some sort of pressure on the nerve in question or some other nerve issue (infection, RSD, etc.). This may be a case for a neurologist. Sometimes the bone has to be reduced, just to have enough room to make dentures or other prostho services. Does not fit means a number of things, but if it does not fit , it does not fit.

A couple of thoughts. For those advocating a rigid connector such as a palatal strap in the construction of a maxillary implant- retained overdenture, does it concern you that if a black fabricating male is used to secure a stud attachment to the denture, when the black male is replaced with a colored male how can it fully engage if the rigid connector is firmly seated against the midline? The same would be true with a resilient type bar. It would seem that if a rigid connector is to be used, the use of a resilient attachment must be modified, so that they become, in effect, rigid, in order to predictably engage the abutment. In the case of a locator stud attachment, perhaps it should be place into the denture without the use of a black processing male, but rather the actual male being used.

Patient with edentulous maxilla, 4 osseointegrated unsplinted implants at canines and first bicuspids with healing cuffs. Wants removable overdenture, not fixed or hybrid, but no bar. We hesitate to recommend fully implant-supported overdenture in this situation. But patient says he does not want prosthesis moving when he chews. That rules out resilient abutments like Zest locators, Rhein83, Sterngold ERAS, etc. We're thinking rigid Dalla Bono, simple and economical, but then ball joints are implant-bearing. Any advice? Would love to see Dr. Soltys' midline overdenture reinforcement, but have not found pix. Also have read here that closed oval (not horseshoe) works well with 4 unsplinted implants, but resilience of abutments is still a problem in both cases, right? So situation is still the same. Any suggestions for best compromise? 4 maxillary implants, unsplinted, no bar, no overdenture movement when patient chews (that he is aware of). Ridge and bone OK but maxilla is always tricky.