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Thursday, May 27, 2010


Mini dental implants are here to stay. The short learning curve and simple protocol to place them means that dentists will be trained faster and such treatment is affordable to the vast majority of people especially in the developing world. However, it must be pointed out that basic medical and surgical principles apply and a sound knowledge of oral anatomy, bone physiology and proper treatment planning is essential for long term success.

For the patient, is it better to make a big hole or a small hole in the gums?

For the dentist, is it better to do a simple less problematic procedure, or a complex more problematic procedure which may in the end achieve similar results.




Larger or Smaller Diameter Dental Implant

K. F. Chow BDS., FDSRCS May 27th, 2010
The primary cause of the failure could be systemic or local. The patient is middle aged, with high BP and high cholesterol, hopefully controlled. Check the patient for diabetes and treat if necessary.
Dues should be paid to Dr Vaziri for highlighting the possible local causes like residual infection left behind by the endodontically treated tooth and the possibly low blood supply to the periodontium of such teeth that may prevent proper osseointegration.
Having said that, Carlos Boudet gave a very reasonable and workable local treatment response to the problem. But the possible systemic causes should be looked at first.
Lastly, a larger diameter implant is an absolute no no.
Besides all the eloquent reasons given earlier by the learned dentists not to do so, I would like to add one more.
Every dental implant we place also comes with a periodontal pocket….yes a pathology…. an iatrogenic condition. Bone will forms a biologic bond with titanium but the gums do not. What we have is a far cry from the sophisticated gingival cuff around a real tooth with the epithelial attachment and a well planned organisation of different types of fibres all designed to prevent infection from penetrating the emergent margin of the tooth.
If we have to make a perio pocket everytime we place and implant, it makes good sense to make a small diameter pocket rather than a larger diameter pocket that comes with a larger diameter implant. If we have to make a hole in the gums, make a small one as far as possible…. a smaller diameter ….not a larger diameter.

Thursday, May 20, 2010

Platform Switching and the Kai Foo's Three Critical Margins of Dental Implants

  • K. F. Chow BDS., FDSRCS May 20th, 2010
    The term “platform switching” may be a misnomer. Misnomer means using the wrong word to describe something. The platform that we are referring to is the round surface area on top of the fixture in which the screw hole for the abutment is located. Branemark set the trend by making sure that the abutment fits exactly over the top-surface of fixture, with the periphery flush with each other……which is a logical decision at the time….and everyone copied him…….which always resulted in a “normal” resorption of the bone away from the junction.
    The advantage of “platform switching” was discovered when a dentist did not have the right sized abutment to fit flush with the fixture and inserted an abutment whose circumference/undersurface area was smaller than the platform/topsurface area of the fixture. This happily and unintentionally took the junction/microgap/microorganisms away from the bone and thus to the pleasant astonishment of the dentist after reviewing the xray, showed that the so-called acceptable normal resorption of the bone away from the implant ceased!!
    Thus “platform switching/shifting” was born. The platform however remained the same and was never switched or shifted. That is why i think that it is a misnomer, i.e. wrong word. What changed was the circumferential size of the abutment. An abutment with a smaller circumference than that of the fixture was then resting on the top-surface of the fixture.
    Maybe the right term should be “abutment downsizing” or “footprint reduction” or just simply “platform mismatch” or “margin shifting” or “green technology” or …”gum friendly”…or “shy margins”…….. oh hack…just call it “platform switching” to comply with the aura of mystery and awe that implant dentistry should continue to have for old times sake!!!!!!
    If you understand the concept, then you can easily see which implant system is platform switching and which is not.
    There are 3 critical margins in implant dentistry. I call them "Kai Foo's Three Critical Margins". The abutment-fixture margin, the crown-abutment margin and the emergence margin…altogether is found within the transmucosal passage of the implant.
    Platform switching has solved the problem of the abutment-fixture margin. Most savvy manufacturers are all moving towards this design. The crown-abutment margin is still unresolved whether you screw or cement, it still poses an inflammatory problem.
    As for the emergence margin… solution may be to reduce the circumference by reducing the diameter of the emerging dental implant. But with our emphasis on the “emergence profile” for the sake of aesthetics, it is unlikely to be practiced widely. As the Chinese have a saying..”Oi lang…Ng moi mang”…which translates as wanting beauty even at the expense of life and health.
    ‘Nuff said.

Wednesday, May 12, 2010


Dear Visitors,

Will be in Seoul to attend a Scientific Symposium on Implant Dentistry.
Also will deliver a talk on Narrow Diameter Dental Implants: Its History and Clinical Uses.
Will load the pictures on the Buddy System when I return in a week or so.

Dr. Chow


  • A direct impression was then made with a high quality precision type of alginate or silicone/rubber base material. The resulting models were then sent to the dental laboratory to construct the necessary three unit bridge 654/. Alginate is more than adequate because we are not dealing with real teeth but implants and the accuracy obtained is adequate. A temporary bridge may or may not be placed since aesthetics is not a concern here. In this case, no temporary bridge was placed. The BUDs acted as comfort caps over the implants since they were designed to be rounded and smooth.
  • Once the bridge was constructed, the patient was recalled and after testing in the mouth and adjusting the bite where necessary, the bridge was cemented over the BUDs with a suitable cement. In this case, glass ionomer was used. A temporary cement may be used for the sake of retrievability. Once the excess is removed, the crown and bridge is then functional. The underside of the bridge is accessible to cleaning with a floss and a bridge cleaner with the help of interdental brushes.
  • This is a patent pending product.

Tuesday, May 11, 2010


As a result of the current less than satisfactory prosthodontic solutions for the mini dental implants, a new solution has been developed. This method is called the “BUDDY METHOD” and is described as follows for replacing the right upper premolars and first molar. It can also be used in all parts of the mouth. The method is described as follows:-

  • Mini dental implants were inserted parallel to each other with 4mm sticking above the gums. This will include the O-ball head and neck with about 0.5 to 1.0mm of the collar sticking above the gum. Minis from Imtec or Intralock or others of similar design can be used.
  • The BUDs{Bridge Underpinning Devices} were snapped onto the 56/ mini dental implants. The snap-on and snap-off function is simple, repeatable, precise and lends itself to impression taking without easily coming loose or shifting. They are checked to make sure the base of the BUDs are flush with the mucosal surface or are pressing down upon the mucosa from between 0.5 to 1.0mm deep into the mucosa surface. The base of the BUDs are designed such that they will not cut the mucosa but merely compress the mucosa a little, much like that of the pontic of a conventional bridge. After checking that there is good contact between the base of the BUDs and the mucosa surface, the BUDs are then snapped off the heads of the mini dental implants. A permanent cement like polycarboxylate, glass ionomer or zinc phosphate can be placed into the BUDs and they are then snapped back onto the mini dental implants. Once the cement is set, the excess can be removed with a sharp probe or a scaler.
  • The remaining dental implant for some reason could not be placed parallel to the rest. In order to correct it, a moulding device was loaded with a light cure composite and inserted over the implant head with a rubber dam between the composite and the mucosa and then light-cured. The rubber dam is to give the composite a smooth surface against the gums. The moulding device was removed, leaving a composite BUD over the mini implant. The composite bud was then shaped with a tapered diamond bur in order to gain parallelism with the other 2 implants.
To out for some pictures. Check out where I am progressively writing a comprehensive book on mini dental implants......cheers!

Monday, May 10, 2010


A more elegant technique developed with the use of an impression coping on the mini implant head. The coping came off with the impression and then analogues were fitted into the impression copings before pouring the cast models. The crowns and bridges were then built overt these analogues or over the copings which were then incorporated into the prosthesis. A recurring problem with this technique is the tendency of the impression copings to shift or come loose during the impression taking, resulting in inaccuracies.

A sticky material like composite, glass ionomer or a dental cement can be applied on to the mini implant head. The implant head should be etched beforehand with an acid similar to the one used to etch porcelain. Once set, the build-up can be trimmed into the shape of an abutment. A direct impression can be taken for crown and bridge construction in the laboratory. The downside in this approach is the unknown long term effect of the substance contact with the mucosa around the implant. This may cause a chronic low grade inflammation of the mucosa which may one day deteriorate into peri-implantitis and result in failure of the implant.

To be continued.............check out where I am progressively writing a comprehensive book on mini dental implants......cheers!


When minis were first used to carry crowns and bridges, the main problems were that the heads of the minis were too small to lend themselves for impression taking and difficult prosthodontic construction of crowns and bridges in the laboratory. When cast, the heads would fracture off easily. Several methods have been devised to overcome this problem:-

The lab technicians simply built up the fractured heads of the minis and then constructed the crown or bridge on top of them.  Because of the small diameter of the mini dental implant, the resulting crown always have a base that rests on the mucosa immediately surrounding the emerging implant. This overlapping of the crowns and bridges on the mucosa is universal when restoring mini dental implants. The crowns and bridges were cemented into the patient’s mouth. Whatever gaps present between the crowns and the mini heads were filled up generously with cement. The excess were then removed from around the periphery of the crowns and bridges. These always resulted in a circular margin of cement in direct contact with the mucosa. This direct long term contact of cement to mucosa were assumed to be acceptable and unlikely to cause long term complications. Todd Shatkin’s “FIRST Technique” is basically of this nature and thankfully so far has given little or no problems since it was first used about ten years ago.

FIRST stands for Fabricated Implant Restoration Surgical Technique. This is a highly lab-dependent technique outlined as follows :-

  • X-rays and models are sent to a FIRST Laboratory.
  • A precision made surgical stent is made that will determine precisely the number and position of each mini dental implant to be placed. Even the depth to which each implant is placed is determined by the titanium sleeve that is incorporated into the surgical stent.
  • The final crown and bridge is prefabricated in the FIRST Lab and sent to the dentist together with the surgical stent.
  • All the dentist has to do is to place in the surgical stent and drill the prescribed holes to the exact depth required, all guided precisely by the surgical stent.
  • The mini dental implants are then screwed in to the exact depth as indicated by the titanium sleeves built into the stent.
  • The crown or bridge is tested in the mouth and then filled with a resin cement and cemented into place. All excess cement is removed and the treatment is complete.
To be continued.....................also check out where I am working on my book on mini dental implants.

Saturday, May 8, 2010



Dr. Chow Kai Foo
BDS Singapore, FDSRCS England, Cert. of Implantology Germany, FICD

Mini dental implants were initially used as transitionals. One of the first makers were Dentatus of the U.S.A.  They were placed in between conventional implants so that while the conventionals were osseointegrating, the transitionals were used to support the temporary bridges. However, when the time came to bring the conventionals into function and to remove the transitionals, some of them could not be unscrewed and were found to be osseointegrated. These osseointegrated transitionals were then cut off at the bone level and left in situ. The conventional 2 piece implants were then connected and the prosthodontics completed.

It did not take long for some innovative dentists to decide to use the transitionals to support permanent crowns and bridges. One of them was Dr. Sendax who went on to help form the IMTEC Corporation which produces most of the mini dental implants today.
With the increasing success of mini dental implants, other players began to emerge. Intralock produced the MDL(Mini Drive Lock) mini dental implants. Currently, many companies from countries stretching from Canada, Europe, and all the way to South Korea are rapidly jumping onto the bandwagon to produce mini dental implants which is defined generally as any dental implant whose diameter is anything less than 3mm. The market for minis is currently growing at a rapid clip of 20 to 30% annually, with the IMTEC Corporation leading the pack. It is significant that in 2008, 3M which is a 28 billion USD company bought over the IMTEC Corporation.

The mini dental implant market is growing rapidly because of the following reasons:-

  1. USFDA approval of IMTEC mini dental implants for long term use. This gave an added boost to many dentists worldwide the confidence to use minis.
  2. The simple surgical procedure involved resulted in rapid healing, shorter treatment time, and a much lower cost than conventional 2 piece dental implants.
  3. Simplicity of instrumentation and placement procedure allows for rapid training of dentists and a much shorter learning curve.
  4. Patients were pleased with the quickness of delivery of the implants and prosthodontics together with the minimal trauma involved. In many cases, patients were pleasantly surprised by the lack of bleeding and pain due to the flapless procedure employed. Many patients have benefited since then, especially in cases of lower full dentures where the loose denture can be stabilized removably in a predictable manner in one visit of one or two hours.
To be continued.........


  • K. F. Chow BDS., FDSRCS April 6th, 2010
    Many of my complex cases are treatment planned with both narrow diameter and regular diameter dental implants. My experience in cases when I use only narrow diameter is that I complete my cases much faster than when it involves regular diameters. As such, it behoves serious practitioners to keep both types in mind when treatment planning because I forsee that we are beginning to shift towards a more balanced and sensible approach rather than a prejudiced and narrow approach.
  • Dr. Chow: I agree.
  • sergio April 7th, 2010
    Couldn’t agree with you more, Dr.Chow.


K. F. Chow BDS., FDSRCS November 13th, 2009
Thanks for the kind words guys. While I am yet feeling elated and therefore a little brash, let me push the debate a little further.
We all know that the transmucosal passage of the dental implant when compared to the transmucosal passage of an actual, real, original living tooth is actually a pathetic imitation of the real thing. The real thing has a nice epithelial attachment with a nice drain around the tooth constantly flushed with antibacterial substances and prohealth nutrients for the gingivae. Not only that the gingival cuff has circular fibres, connective tissue to tooth fibres, bone to tooth fibres , connective tissue to bone fibres etc. that gives each tooth a nice firm resilient yet elastic cuff around the it. Go review your periodontology texts and see for yourself.
The dental implant has only a pseudo epithelial attachment and a few if any specialised soft tissue fibres and at best is actually an iatrogenic and pathetic imitation of the original! The Archilles heel of dental implants is this transmucosal passage. Peri-implantitis is a problem we all have to tackle like periodontitis. And with dental implant placement growing in the double digits around the world, it is going to be an increasing problem.
The best solution is probably a tooth germ implant which may be a generation away. We may be stuck with dental implants for some time yet.
One way to tackle it and hopefully to decrease the incidence of peri-implantitis may be to decrease the diameter of the implants as it emerges through the mucosa. One shortcoming of conventionals is its large diameter especially done in the name of an aesthetic emergent profile. Narrow diameters may be one of the answers to decreasing and managing the incidence of peri-implantitis.
Nuff said.


  • Ken Clifford, DDS October 24th, 2009
    Dr Chow - Amen to all your comments. There is absolutely no reason not to use mini implants. I have been cementing full arch mini implant hybrid bridges as a denture alternative for the past two years. My opinion is that a CEMENTED bridge on mini implants is an affordable alternative for patients unwilling or unable to pay for the all on four bridges, or the conventional implant porcelain/metal solutions. Cementation to minis eliminates the micromovement responsible for most implant failure in a full arch situation. By using quality denture teeth and a quality denture acrylic with high flexural strength, I can quickly construct a highly aesthetic denture alternative which can be loaded immediately. Patients go home happy, and so do I!
  • Paresh B Patel October 27th, 2009
    Dr. Chow, thank you for your well organized and eloquently articulated thoughts on the current state of mini implants. I look forward to reviewing your text “Minimized Dental Implants”


K. F. Chow BDS., FDSRCS October 23rd, 2009
Narrow diameter dental implants are being increasingly used not only to stabilize dentures but also for long term applications like crowns and bridges. I agree with Carl in that there is no such thing as an absolute contraindication in medicine. Even botox which will kill you if injected into your bloodstream is used ingeniously and judiciously to extend the youthful looks of people. The key word is “judiciously”. Know your medicine well and know what you want to do with it and then you can apply it safely and usefully.
It is significant that one of the doyens of implant dentistry has recognized that narrow diameters have their uses especially in narrow ridges and in suitable bone. I started out with conventionals and with the advent of minis, incorporated them into my treatment planning and in many complex cases have successfully integrated them both into my treatment planning taking into consideration the patient’s expectations and budget,the materials available and their limitations and my own experience, knowledge and skill.
However, with the greatest of respect, having read the classic Contemporary Implant Dentistry, I wish to highlight some misconceptions and give my opinion.
As pointed out earlier, many narrow diameters or minis used for fixed applications are 2.4mm to 2.9mm in diameter and are made of solid titanium alloy grade 5. They are certainly stronger than say a 4mm diameter fixture that has a hole in the middle to receive an abutment. Say the abutment is 2mm in diameter. That leaves the surrounding rim with a thickness of only 1mm! That is weaker definitely than a solid 2.5mm diameter mini. Furthermore, many of the conventional fixtures are made of titanium grade 3 or 4 which is 99.9% pure titanium and is softer and therefore weaker than the alloy.
One piece minis heal very well if they are placed in with a torque of at least 35 to 50ncm.Reason being that the healing challenge is much less than conventionals and also the transmucosal wound is very small, so that chances of infection in a normal patient is minimal.
As for the misconception that the surface area is insufficient, Paresh Patel has given an eloquent correction to that. Minis are usually placed longer than conventionals and in multiples. So as Patel has pointed out, two 2.5 by 10mm minis give a total surface area of 157sq mm. This has a greater surface area than a conventional of 4 by 10mm which gives only 125sq mm. 2.5 by 13mm gives 100sq mm. 2.5 by 16mm gives 125sq mm. All these are commonly used such that the argument of insufficient surface area for osseointegration holds no water.
The initial or primary stability of minis, I find often surpasses that of conventionals. In fact, I surmise that because of the minimal trauma and small entrance, the surrounding bone and soft tissue has overwhelming healing advantage when compared to conventionals that invokes a much greater healing challenge to the surrounding tissues. The overwhelming healing advantage in the context of minis may mean that the classical necrotic margin phase of osseointegration may be bypassed and osseointegration in the case of minis may be taking place almost immediately. Anyone wants to do a PhD on this?
Narrow diameter users must concede however that the charges of inadequate prosthodontic solutions to solve the problems of non-parallellism, insufficient prosthetic components, and poor emergence profile may have some credence. These problems I believe are being sorted out. As it is, narrow diameters or minis are here to stay and will be increasingly integrated into treatment plans to cater to all sorts of situations that it can solve much better than conventionals. I look forward to minis making great strides to make the benefits of implant dentistry affordable to everyone who needs them, and not just to the well-off only. I forsee that they will play an increasingly greater part in the development of implant dentistry and am preparing a book…”Minimized Dental Implants” and hope to outline and deliver elegant prosthodontic solutions to minis that will address the current shortcomings as pointed out.

Friday, May 7, 2010


Dear Dr A,
I guess you are another fictitious Doc with an alphabet. Nevertheless, it is an interesting question.
If you do not want to do a sinus lift, any reason will do though it might not be a good one. I myself once did not want to do it because I hated having to make a large opening into the sinus! And if I can avoid it, I did. So I tried crestal lifts invented by Summers. Works, but often found myself having to spend more time than if I just did a lateral window which is more sure and definitive. There are various ingenious ways nowadays, the latest seem to be the “hatch” technique with a special off centre drill.
However, if you want to avoid all these, there are several ways to avoid a sinus lift altogether:-
* Do a conventional bridge on adjacent teeth. Use the tooth in front and the tooth behind the edentulous space. Or a cantilever might work.
* Place an implant in the tuberosity where there is usually more than enough bone and join it to the natural tooth just anterior to the edentulous space.
* Or use MINIs! Do a tripod. 3 minis with the tips cut off at 5mm length, and build a crown on it.
* 2 or 3 Minis carefully threaded into the walls of the sinus on the buccal and the palatal where there is usually 3-5mm thickness of bone. These technique requires a lot of skill and experience though.
* Use short large diameter fixtures from Bicon, Endopore or some of these Korean makers that come in diameters up to 8mm!
* Or like Dr Richard Hughes suggest…. place in a subperiosteal.
Now all of the above require quite a lot of skill and experience…..maybe you might just want to learn to do a lateral window sinus lift which actually, once you get the hang of it may be actually simpler and surer in results!