A BRIEF HISTORY OF DENTAL IMPLANTS:    a dream come true

Dr. Chow Kai Foo

BDS Singapore

FDSRCS England

Cert. of Implantology  Germany

A PRECOCIOUS CENTURY

We are now into the 21^st Century. The previous century, the last century of the millenium, the 20^th Century was a precocious century. Precocious because it has superceded the previous 50 centuries of recorded human history and civilization in terms of the accumulation of knowledge. In one quantum leap of a single century, we increased many many times more than all the raw knowledge accumulated in the previous 50 centuries of recorded  history. Today, we can no longer master a subject in a few short years of intense study like in the 19^th century backwards. We can only launch ourselves into the beginning of a lifetime of learning, focusing on the subject or profession of our choice constantly looking out for the sudden breakthrough that may  rearrange all our past knowledge of the subject.. Because knowledge has become so vast and increasing so fast continuously, we cannot afford to stay still, but to keep on and on learning.

A DREAM COME TRUE

In the field of dentistry, it is fitting that the dream of its practioners for thousands of years have at last come to pass in the last century, the audacious century, or some might want to call it the precocious century. Today, a dentist can replace a lost tooth at will and almost as good as new! As dentists, or stomatologists, which is a more accurate term, we are extremely fortunate to be practicing today.

“The goal of modern dentistry is to return patients to oral health in a predictable fashion. The goal of modern dentistry is to restore the patient to normal contour, function, comfort, esthetics, speech and health, regardless of the atrophy, disease, or injury of the stomatognathic system.”     Carl E. Misch

While it remains fresh in my mind may be the best reason why I must blog this particular portion in. At the ITI meeting in Kuching/Malaysia on Thursday May 24th 2012, I was listening to Dr Chatchai Kunavisanut from Thailand speaking on the topic, "Reduced diameter implant: A solution for a narrow ridge", and then giving his opinion on it. He duly showed a case where the lower anterior ridge was very narrow, and he placed two minis to replace two incisors in an "experiment"!?!!  It was a clear contradiction against his own advice not to use minis. On his final slide, he showed pictures of two mini implant cases in which he casually pointed out that they are bound to fail. The conclusion then was, "do not use mini dental implants!".

One look at the two pics and I immediately recognized them to be from my blogspot: smalldentalimplants.blogspot.com.  When it came to discussion on what had been shown, I stood up and readily confessed that those were my cases, one on the upper right and one showing the lower left molars built on mini dental implants. I duly informed the speaker and the audience that contrary to them failing, they were still in my patients' mouths when I last saw them barely a few months ago and after at least 3 years after the minis were placed!!! After checking my blog:

http://smalldentalimplants.blogspot.com/2010/05/blog-post.html

http://smalldentalimplants.blogspot.com/2010/08/bone-climbing-up-mini-dental-implant.html,

I must correct myself, it was the lower right molar, not the lower left.


The mistake that I made was that I went on and on elaborating on why we should not judge minis prematurely and that all serious implant dentists should treatment plan with both minis and conventionals in mind...... and so on.  I should have just set down and let the dear doctor defend what he just said. It was already the end of the meeting and the moderator was pointing at his watch. When I sat down, Dr. Stephen Chen from Australia insisted on replying to what I said. He said that treatment should be evidence based and not anecdoctal and basically challenged me for the studies that can support the wider use of minis and if so proven, he will be one of the first to start using them! In addition, they will even give me a slot in Bangkok to speak at the ITI Congress South East Asia in Bangkok Thailand in May 16-17 2013. I immediately took up the challenge and said that I will get the retrospective study from my own practice and also from the practices of some of my colleagues in Malaysia. Yap, a multi-centre retrospective study! Challenge thrown, challenge taken and the study is going to be ready. Check out the link below as well to read the debate over narrow diameters with an initial query from Carl Misch himself and a final closing comment from yours truly here.

http://www.osseonews.com/narrow-diameter-implants-are-there-absolute-contraindications/

How I Got Hooked.

Before I could bring myself to place in the first dental implant into my patient’s jaw, I had to overcome the difficult mental block of believing that it is actually possible for a missing tooth to be replaced by an artificial implant.

Throughout my dental school training and into my subsequent years of treating various types of dental diseases, the incessant mantra that was emphasized again and again and again was the need to prevent inflammation of the tissues in the mouth, especially the soft tissue. Time and time again, I observed how vulnerable teeth can become once the gums have become inflamed. Inevitably, the inflammation was associated with foreign elements like pathogenic bacteria in plaque attached to teeth and fillings and prostheses. The idea of a foreign element being embedded into the gums and bones, sticking out into the mouth, then expecting them to stay there and undergo continued stress and hoping that they will be maintained there for years was considered a pipe dream.

In order to overcome the mental block, I decided to read as much about dental implants as possible. I paid special attention to the landmark discoveries and writings of Professor Braunemark of Sweden.  I spent a small fortune buying his books and others like it and reading them all. This intellectual exercise helped me to substantially overcome the deep seated skepticism that I felt towards dental implants to the point that I felt that I was ready to take on my first patient. Having convinced my first patient to have dental implants placed in her mouth, I proceeded to do a sinus lift simultaneously with 3 conventional implants placed on the upper left maxilla! I planned carefully and worked down all the steps required and read up all I could to prepare for my first implant surgery.

Then I followed the steps faithfully and stitched up the wound. Four months later I placed in some healing caps and a week later removed them. The sight of the healthily pink and well healed gingiva, like a well formed crater in the gums at the bottom of which I could see the shiny surface of the titanium fixture was something I can never forget. There was little or no inflammation and no bleeding. It struck me convincingly and clearly that titanium is biocompatible with the bone and mucosa of the human body.

From that moment on, I was hooked. Dental implants work!

                                          

Why shouldn’t we, as responsible professionals make oral implantology less invasive and as simple as possible? This will not only lower costs, it would decrease clinical time for the doctor and recovery time for the patient. On top of it, such procedures have been proven to be relatively pain free.

(6) One reason why mini- implants can be loaded immediately as a matter of routine is because there is minimal trauma to the bone. As such, the process of osseointegration begins immediately on implantation. There is no transitional margin of necrosis between the implant and bone which is found in conventional implant placement. Also, because the mini- implant is small, the healing challenge to the surrounding tissue is correspondingly small and the tissue heals rapidly and almost immediately.

The healing challenge of the surrounding tissue in the case of the conventional implants is much more and requires a longer time, thus immediate loading of conventional implants often is less successful.

(7) The actual surface area of minis are actually comparable to the surface area of conventional size dental implants. This is because minis are usually place deeper and therefore longer than conventionals, thus increasing its effective surface area available for osseointegration.

• A conventional sized dental implant 4mm diameter and 10mm long has a surface area of about 125 sq mm.
• A reduced diameter dental implant 2.5mm diameter and 10mm long has a surface of about 80sq mm.
• A reduced diameter dental implant 2.5mm diameter and 13mm long has a surface of about 100sq mm.
• A reduced diameter dental implant 2.5mm diameter and 16mm long has a surface of about 125 sq mm.
• A reduced diameter dental implant 2.5mm diameter and 19mm long has a surface of about150 sq mm.

Thus  a mini that is 2.5mm diameter and 16mm long in its threaded area has a surface area equivalent to a conventional sized dental implant 4mm diameter and 10mm long.

In my experience, this length is one of the most common mini used and very often 2 minis are used to restore one molar. Two minis 2.5mm diameter and 10mm long has a surface area of 160 sq mm! This is more than that of a conventional 4mm diameter and 10mm long. Two minis 10mm long is more than adequate for one molar since very often one molar is restored by a conventional that has a surface area of only 125 to 150sq mm.

ANSWERS TO QUERIES:- MINIMIZED DENTAL IMPLANTS: THE COMING WORKHORSE IN IMPLANT DENTISTRY

These reasons can be readily addressed when the facts are laid down clearly:-

(1) Mini- implants are made of titanium alloy, i.e. is size for size, 1.6 times stronger than commercially pure titanium. The diameter of mini- implants range between 2.0mm to 3.0mm. Mini- implants are actually less prone to fracture because it is solid.

Conventional implants are more prone to fracture because they consist of 2 pieces with a connecting screw in between. If a conventional implant is 4.0mm in diameter and the connecting screw is 2.0mm in diameter. The thickness of the remaining wall of the implant fixture is only 1mm. Compare this to the mini implant which is 2.5mm in diameter or thickness, which is stronger? The mini- implant…… believe it or not is stronger than the conventional implant! It is less prone to fracture than the conventional implant.

(2) Additionally, the 2 piece conventional implant is connected by a screw which has a tendency to come loose and even fracture. Also, there is a microgap between the 2 pieces of the conventional implant which harbour microorganisms that causes bone resorption and sometimes implantitis. Such a chronic source of pathogens in the body may cause coronary artery disease with the accompanying sequelae.

(3) Just because mini implants were designed to be transitionals should not mean that they cannot be used permanently. Many mini- implants have been used for crowns and bridges in the last 10 years successfully. The concept that an implant root should imitate the root size of the tooth it is replacing is largely an assumption by the pioneers of implantology. The basis should have been a study of how much osseointegrated surface is required to withstand the masticatory forces of a particular tooth. It should be reasonable to assume that the surface area of osseointegration may be less than the surface area of the periodontal ligament of the tooth to be replaced , since osseointegration square mm to square mm is much stronger a bond than the bond of the periodontal ligament, although without the shock-absorbing ability of the periodontal ligament. It is much more easier to extract a tooth than an osseointgrated implant. In fact, you cannot extract an osseointgrated implant. It is reasonable again, therefore, to assume that an implant that is half the size of a tooth root will give sufficient surface area of osseointegration to carry the tooth and its masticatory functions.

(4) Titanium osseointegrates, and if mini- implants are made out of the same stuff as conventional implants, they osseointegrate.

(5) The whole world of surgery is moving relentlessly towards minimal invasiveness as shown by the rapid change towards laporoscopy and closed surgery as far as possible. 

by Dr. Chow Kai Foo
BDS Singapore; FDSRCS England
Cert. of Oral Implantology University of Frankfurt Germany
FICD; Academy of Medicine; National Specialist Register

President of the Malaysian Oral Implant Association 2009-2011
Currently Advisor to the Malaysian Oral Implant Association

QUERIES:- MINIMIZED DENTAL IMPLANTS: THE COMING WORKHORSE IN IMPLANT DENTISTRY

(1) Mini-implants were considered too small in diameter and therefore its ability to withstand masticatory forces over long periods of time were doubtful.

(2) Mini-implants were used originally as transitories and therefore should remain so.

(3) The surface area of mini- implants compared to a conventional implant is too small and therefore the amount of osseointegration is insufficient to withstand masticatory forces.

(4) Mini- implants do not osseointegrate.

(5) It goes against the original tenets laid down by Professor Branemark where it is accepted wisdom that the size of the implant fixture should imitate the size of the root of the tooth that it is replacing.

(6) The emotional element also comes into play, as in, “How can oral implantology be so simple and easy to do?” Emotionally it is difficult to accept that a previously complex procedure can be bypassed with a simple approach.

(7) How can you load mini-implants so routinely when conventional implants usually cannot be loaded immediately, and when done so, only progressively?

by Dr. Chow Kai Foo
BDS Singapore; FDSRCS England
Cert. of Oral Implantology University of Frankfurt Germany
FICD; Academy of Medicine; National Specialist Register

President of the Malaysian Oral Implant Association 2009-2011
Currently Advisor to the Malaysian Oral Implant Association

CHAPTER ONE: MINIMIZED DENTAL IMPLANTS- THE COMING WORKHORSE IN IMPLANT DENTISTRY

CHAPTER ONE

INTRODUCTION

While I would like spend a lot of time reading up all the journals I can lay my hands on and including all their references as part of this book, I realize as a clinician with a busy practice and a large family commitment, my time has to be prioritized carefully.

However, the need for this book cannot wait. There is a huge debate currently on whether or not mini implants or small dental implants or as I prefer to call them MOSTDIS (Minimised Osseointegrated Screw Titanium Dental Implants) should or should not be used for the long term fixation of crowns and bridges.

In the last few years, there has been a widespread concession that mini-implants can be used for denture stabilization. I use the word “concession” as (opposed to “consensus”) because previous to that, mini-implants were frowned upon as transitionals pretending to be “genuine” implants. Historically, mini-implants were used as transitionals that were placed between the conventionally sized dental implants to hold the temporary prosthesis while waiting for the conventional implants to osseointegrate. When the time came to remove the temporary prosthesis, some of the transitionals were found to have osseointegrated  and were impossible to unscrew. Often, the head of such osseointegrated mini-implants were cut off and the endosseous part left in situ. Over time, it occurred to some practitioners that transitories or mini-implants can be used in a more permanent or long term manner.

Initially, mini-implants were used more for denture stabilization. Subsequently, some practitioners tried cementing crowns and then bridges on top of the mini-implants and more often than not were found to be successful, especially in the mandible. Such practices were frowned upon and even condemned by oral implantologists because of several reasons:-

by Dr. Chow Kai Foo
BDS Singapore; FDSRCS England
Cert. of Oral Implantology University of Frankfurt Germany
FICD; Academy of Medicine; National Specialist Register

President of the Malaysian Oral Implant Association 2009-2011
Currently Advisor to the Malaysian Oral Implant Association