Thursday, March 7, 2013
CHAPTER FOUR: THE BUDDY SYSTEM OF RESTORATION FOR MOSTDIS
COMPONENTS OF THE BUDDY SYSTEM OF IMPLANT DENTISTRY
BUD: Bridge Underpinning Device
The bud is basically a coping with an O- RING incorporated inside to give a positive repeatable precision placement onto the SDI. It is quite similar to the dental anchoring device (DAD) used with small dental implants. It consists of a housing with an O-Ring incorporated inside.
The BUD is shaped more like a tooth abutment. Larger than the DAD(Denture Anchoring Device), it is about 5mm in height. The MOSTDI is screwed down until only about 4 to 4.5mm is sticking out above the gum level. This results in a smooth metal interface with the mucosa immediately around the SDI. The bud can be cemented and trimmed to size or left as it is, if trimming is unnecessary. The impression is then taken and sent to the lab for crown and bridge construction.
If the bud is not cemented, it can be used to carry a temporary crown or bridge. This can be removed easily when a more permanent restoration is constructed. If a temporary cement is used to cement the BUD onto the abutment, the crown and bridge can be retrieved with a crown remover. Such a BUD can also be used as a DAD with the added advantage that if none of the SDIs are exposed, cold curing of the denture will not go into any undercuts. As such, after cold curing, the denture can be removed with a steady and sustained pull force on the denture. However, if any part of the SDI is exposed, it can be protected with one or more O-rings. The orthodontic elastic separators (O-rings) can be used.
(1) MOSTDIDAD/ MOSTDIBUD
(2) BUD IN USE IN MOUTH
(3) BUD WITH BLUE O-RING
Saturday, February 16, 2013
The lower right first molar was extracted due to severe periodontitis resulting in loss of bone support. Two mini dental implants were immediately inserted into whatever bone was available. The patient was covered with antibiotics for several days. A porcelain bonded to metal crown was fixed about 2 months later over a composite core that was lightcured over the minis. Six years later, an xray was taken.... looks like the bone has "climbed up" the implant. The tooth was firm and functional.
A NEW WAY TO REGAIN ALVEOLAR BONE SANS GRAFTS?!!
A NEW WAY TO REGAIN ALVEOLAR BONE SANS GRAFTS?!!
A SIGNIFICANT PARADIGM SHIFT IN THE GROWING BACK OF ALVEOLAR BONE
Human Histologic Verification of
Osseointegration of an Immediate
Implant Placed into a Fresh Extraction
Socket With Excessive Gap Distance
Without Primary Flap Closure, Graft, or
Membrane: A Case Report
Dennis P. Tarnow, DDS*
Stephen J. Chu, DMD ,MSD, CDT**
* Clinical Professor and Director of Implant Education, Columbia University College of
Dental Medicine, New York, New York.
** Clinical Associate Professor and Director of Esthetic Education, Columbia University
College of Dental Medicine, New York, New York.
This case report provides
clinical and histologic proof that the immediate placement of implants into
extraction sockets with an intact buccal wall allows healing and osseointegration
despite a large gap distance and without primary flap closure, a bone graft, or
a barrier membrane. (Int J Periodontics Restorative Dent 2011;31:515–521.)
In the discussion, the following statement was made:-
It is possible then that an
implant placed in an extraction site
without soft tissue closure could
heal with bone-to-implant contact
before the soft tissues have an opportunity
However, I beg to differ.
Based on the case shared on "Bone Climbing Up Mini Dental Implant",
my postulation is as follows:-
In spite of the absence of a buccal and lingual plate, no well defined socket,
a mini dental screwed into the cortical plate at the bottom of the bony crater
left behind by a mobile, periodontally compromised tooth,
will stimulate the alveolar bone to reform and grow around the implant
to a more normal level
in spite of the presence of granulation and epithelial tissue.
Friday, February 15, 2013
SINGAPORE ACADEMY OF MEDICINE GIVES MINIS THE NOD
SINGAPORE ACADEMY OF MEDICINE GIVES MINIS THE NOD
ESPECIALLY FOR LOWER FULL DENTURE STABILIZATION
A LANDMARK DECISION AND ONE OF THE FIRST IN THE WORLD
BY A RESPECTED HEALTH AUTHORITY
1. The Academy of Medicine Singapore with the Singapore Ministry of Health and other dental specialist bodies has recommended narrow diameter dental implants to be used for mandibular denture stabilization.
The recommendation comes with a high rating of Grade B, Level 2++. This rating means that it is recommended for use on patients and is supported by high quality systematic reviews of case control or cohort studies. Patients with implants between 2.5mm to 3.3mm for mandibular overdenture retention had good survival rates of more than 98% in two prospective studies.
2. Below is the link to download the latest clinical guidelines for implant dentistry in Singapore:
3. It was compiled by a committee of 22 implant dentists in Singapore. They referred to 121 respected papers from all over the world. These guidelines are endorsed by the Academy of Medicine Singapore, Ministry of Health, Society of Periodontology, College of Dental Surgeons, Association of Oral and Maxillofacial Surgeons and Prosthodontic Society of Singapore. Dated August 2012.
On page 19 is the recommendation for narrow diameter dental implants for mandibular overdenture retention. Although there is no comment on the use of minis or narrow diameters for crowns and bridges, there is no disapproval either. It usually means that the jury is out and practitioners should use them responsibly as they see fit.
If you go to the link immediately below, there is posted one of the most comprehensive debates on the use of minimized dental implants for lower full denture stabilization:-
RESORBED MANDIBLE BEST TREATMENT PLAN DEBATE
RESORBED MANDIBLE BEST TREATMENT PLAN DEBATE
LOWER FULL DENTURE STABILIZATION
LOWER AND UPPER FULL DENTURE STABILIZATION
LET US BRING THESE SIMPLE AND AFFORDABLE TREATMENT
TO EVERYONE WHO NEEDS THEM
THROUGHOUT THE WORLD!!!
Tuesday, November 6, 2012
CHAPTER THREE: THE PRACTISE OF ORAL IMPLANTOLOGY USING MOSTDIS
BASIC INFORMATION ON MOSTDIS
OSSEOINTEGRATION IN THE USE OF MINI-IMPLANTS
Mini-implants, narrow diameters, small diameters, reduced diameters, MOSTDIs are all made from titanium and they all osseointegrate, just like conventional sized dental implants. Mini-implants, due to their smaller diameter and minimally invasive placement technique results in a much smaller healing challenge to the body and therefore probably integrate even faster. In addition, they are usually placed up to a torque of 50 ncm as compared to 30 ncm in the case of conventional. This can be done because minis are solid one piece implants and are actually stronger in resisting fracture than conventionals that have a hole within the fixture which weakens it considerably and does not allow the driver to apply a high torque to it. Thus minis can and are torqued to a higher level than conventionals, giving it a stronger primary stability that allows immediate loading and faster finishing than conventionals.
RETRIEVABILITY IN MINI- IMPLANTS
The ongoing debate in oral dentistry is whether or not a prosthesis should be screwed on or cemented. In his landmark lecture in 1982 in
Professor Branemark showed successful cases of endosseus screw titanium dental
implants, all of which were of the two piece design with the prosthesis screwed
on. The screwed on technique was designed to enable retrievability so that if
any complication like a fracture or infection occurs, the prosthesis can be
removed by unscrewing the connecting screw. The implant could then be examined
and remedial action may be taken with direct visual information. TORONTO, CANADA
Over the years, it has been observed again and again that in general, oral implants have an average success rate of up to 95%. Therefore, as argued by some practitioners, since there is only a 5% to 10% failure rate, the prosthesis ought to be screwed on so that they can be retrieved when necessary in order to treat the oral implants directly. This advantage, they feel, offsets the disadvantage of loose screws, broken screws, the need for high precision, the resulting microgap, and the high costs of manufacturing and maintenance of such small precision components.
The other school of thought feels that the combined disadvantages do not justify the advantage of ease of retrievability that is gained with a screw retained prosthesis. After all, if worse comes to worse, the prosthesis can be cut off with a high speed air rotor or a diamond disc with a guard. In addition, dental practitioners have been cementing crowns and bridges for years over natural teeth, even though after 10 years, almost 30% of crowns and bridges that are built on natural teeth fail for one reason or another. The logic therefore is that if we insist on cementing on our crowns and bridges even though there is a 30% failure rate after 10 years, then based on the same logic, there is even greater justification in cementing on our crowns and bridges over dental implants instead of screwing them on.
One solution to this problem is to use a temporary cement like temp-bond and even dycal to cement the implant prosthesis on. Thus if necessary, the prosthesis can be removed with minimal guided force. Temporary cements with its weak bonding strength works over implants because implants are osseointegrated, i.e. ankylosed to the bone and does not move. Natural teeth are attached to the bone via the periodontal ligament which allows the natural teeth to move in tandem with the applied forces, much like the suspension of a car. Therefore, if a temporary cement is used, the cement bond is broken easily especially when there are eccentric forces acting on the prosthesis.
Another school of thought is that when in doubt, use a screw, and when you are very sure of your implant fixtures, cement them in. This philosophy can often cause a crisis of choice when the time to fix the prosthesis comes.
The ideal system seems to be one that would allow easy retrievability without the accompanying disadvantages of a screw retained system. Currently, because of the numerous inherent disadvantages of screwing on the prosthesis, the trend is more and more towards cementation with temporary cement. And after a period of time, if the temporary cement fails, then a permanent cement to fix on the prosthesis is used, the logic being that adequate time has been allowed to ensure the health and stability of the implant.
In the case of mini-implants, retrievability have always been a problem since most crowns and bridges were cemented on permanently. Temporary cements may be a solution but because of the smaller size of the implant head as compared to conventional implants, the prosthesis tends to become unstuck more often. A prosthodontic solution for mini-implants may be to use prefabricated abutments that fit over the small implant head. The resulting abutment is then larger and less likely to fracture in the lab and easier to build a prosthesis on. In addition, the depth of porcelain used will not be so thick as to compromise its ability to resist fracture. The prosthesis can then be cemented permanently on to the abutment and then cemented with temporary cement over the small implant’s head. In this case, the prosthesis can be removed when necessary with a crown remover, thus solving the problem of retrievability. A corresponding technique is to cement the abutments permanently on the MOSTDIs and the final prosthesis can be cemented on the abutment with temporary cement.
The success of oral implantology has been built on the solid advances of crown and bridge prosthodontics that began in earnest since the early 20th century. Initially, crown and bridgework were frowned upon because they were poorly constructed and paid little heed to hygiene, maintenance and material biocompatibility to oral tissues.
However, since the middle of the 21st century with rapid advances in infection control and materials science, crown and bridgework has had unprecedented success in function, aesthetics and maintenance. But the bugbear of having to cut and injure vital teeth proved to be an ongoing problem. Crown and bridgework after 10 years on the average has up to 30% failures, very often due to sequelae and as a result of cutting abutment teeth all the way to dentine. No matter how much cooling water spray we apply, once we cut to the dentine, the pulp undergoes an inflammatory response showing that there is acute damage done to it. Most of the time, the tooth repairs and defends itself successfully. However, there is a substantial percentage of such teeth that undergoes chronic inflammatory changes that later becomes acute if there is bacterial invasion. With the advent of oral implantology, the necessity of cutting vital teeth has become increasingly obsolete. Now crowns and bridges can be built totally on non-vital artificial screw titanium implants. But it is to be recognized that without the advanced development of crowns and bridges on vital teeth, oral implantology will not enjoy the outstanding success it has today.
PROSTHODONTICS FOR CONVENTIONAL 2 PIECE DENTAL IMPLANTS
Since Professor Braunemark’s landmark presentation on his 15 year studies on large two piece titanium screw dental implants in 1982, most implant manufacturers have basically copied his precedents.
The precedents were:-
(1) The use of titanium
(2) Root sized screws
(3) Atraumatic placement
(4) Two piece screw dental implants
(5) Waiting 3-6 months for osseointegration of the fixture before connecting the second piece called the abutment
(6) Building the crowns and bridges on the abutment and screwing them on for the sake of retrievability
Abutments are usually screwed on to the implant proper, usually called the fixture. The abutment itself may have a threaded part that can be used to screw it on or it may have a separate screw to connect it to the fixture. Some implant abutments are designed to fit into the fixture and just tapped on and held there basically by frictional forces. Some abutments may also be cemented onto the fixture.
Crowns and bridges may be screwed on as advocated by Professor Branemark and his followers. Increasingly, many practitioners cement in the prostheses. The rationale for cement over screwing them on are many, the top of which is since we have all along cemented on crowns and bridges event though they have only a 70% success rate after 10 years, what is wrong with cementing on crowns and bridges on oral implants whose success rate is 90% after 10 years.
However, Professor Branemark has an important point in requiring retrievability for his implants. That was why he advocated that the prosthesis should be screwed on rather than cemented on. The additional problem in screw retained prosthesis is the need for passive fit and therefore a very high precision fitting, failing which the improperly fitting prosthesis will give rise to screws loosening or fracturing or implants losing osseointegration. Cementation requires less precision because the gaps can be filled up with cement.
Some practitioners solve the problem of retrievability by using temporary cement. The prosthesis can easily be removed whenever necessary by using a crown remover. Temporary cement works on implants indefinitely because implants are osseointegrated/ ankylosed to the bone and move very little in relationship to other implants since they are all osseointegrated to the same bone. Temporary cement does not work on teeth because teeth can move much more independently of each other and this movement will break the temporary cement and cause the bridge to come loose after a short time.
PROSTHODONTICS FOR ONE PIECE SMALL DENTAL IMPLANTS AND THE QUESTION OF RETRIEVABILITY
There are several problems encountered in building a prosthesis over small dental implants. The issue of whether small dental implants are strong enough to bear crowns and bridges will be addressed in another chapter. This chapter will address mainly the prosthodontic restoration of small dental implants.
The several problems are:-
(1) The abutment portion of the SDI is small. The diameter is usually between 2.0mm to 2.5mm. The small abutment when cast in a model can break easily and thus be problematic to the dental technician.
(2) Building a crown or bridge over a small 2.5mm diameter abutment will result in large amounts of metal or porcelain used. If permanent cement is used and one day the crown or bridge has to be removed for one reason or other, it would be a very tedious process to cut through the thick metal and porcelain.
(3) The small abutment results in very thick porcelain supported by a small metal core. Such porcelain can fracture more easily.
(4) The large surface area interface between the mucosa and the crown or bridge may allow collection of food debris that can give rise to foul smells and infection,
(5) Because of the small diameter of the implant, a good emergence profile cannot be achieved. As such, aesthetics from the anterior teeth may be a problem.
Some of the solutions used so far for the above problems are:-
(1) Prefabricated copings are made. These are precision made to fit over the head of the SDI. They may be connected to the implant and prepared like for a crown or a bridge. Impressions are taken, models are cast and the crown and bridge built in the lab. The copings can also be placed and the impression taken with the copings coming off with the impression. Implant analogues are inserted into the copings stuck in the impression. The casting will have the analogues in place. The copings are replaced and the crowns and bridges built over them.
(2) Composite or glass ionomer material may be bonded on to the implant head and then prepared like for a crown or bridge. The problem in this case is a smooth surface of the composite or glass ionomer in its interface with the mucosa cannot be obtained. The use of a rubber dam or some kind of film will leave a tiny space that may serve as a food trap.
(3)In place of the emergence profile for the anteriors, the anterior crowns are built directly on to the mucosa surface, the surface around the SDIs or the models are relieved generously from 0.5mm to 1.0mm to give the crowns and bridges a slight compression on the mucosa surface resulting in a reasonable emergence profile. This technique has been used very successfully on anterior pontics of bridges. There is hardly any food debris or plaque under the pontics if properly constructed.
Wednesday, September 19, 2012
There are three broad areas in treatment planning, namely:-
- The patient’s expectations and budget: Firstly, ask the patient what are his/her expectations and hopes, and then listen very carefully. It is the patient who is paying for the treatment and it is the patient who has to live with it. The ability to meet and even exceed the patient’s expectations is vital to the success or failure of any treatment plan. Then ask the patient concerning their budget that they have in mind for the cost of the treatment, and then try to work reasonably within the budget.
- The medical and oral condition of the patient: The general medical condition of the patient should be assessed and written down. This can often be done easily with the help of a questionnaire. Based on the questionnaire, the dentist can ask further questions that will help in the treatment planning. Then the oral condition must be checked carefully and then written down.
- The dentist’s expertise and materials available: The dentist should then assess honestly and diligently whether the treatment required is within his capacity. This will determine whether the dentist should go ahead with the treatment, refer the patient to someone who has the expertise, or work together with a fellow dentist who has the expertise. The materials that the dentist have available are important because the particular demands of the case may require certain materials and certain characteristics of the implant system used, and the dentist should determine this before proceeding.
Wednesday, September 5, 2012
CHAPTER TWO: THE THEORY AND PRACTISE OF ORAL IMPLANTOLOGY USING MOSTDIS
The basic requirements of successful oral implantology is caricatured as follows:-
(a) Titanium: It has been proven through the years that titanium is eminently biocompatible to the human body. The surface layer of titanium dioxide is able to form an intimate bond with living bone in the right circumstances. This bond may be either biological or mechanical or both.
(b) Sterilility: The implant must be sterile when placed to prevent infection and to allow an intimate bone implant contact to develop.
(c) Atraumatic Placement: The less trauma to the bone, the smaller the inflammatory response and the more likely osseointegration will take place uneventfully.
(d) Covered Healing: Again this will decrease the possibility of infection.
(e) Retrievability: The principle of retrievability was achieved by using screws to retain the crown and bridges. Screws were used so that the bridges and crowns were easily retrieved by exposing the screws and unscrewing them. Retrievibility was emphasized by the professor during that pioneering period so that if any complications arose around the implants, the crowns and bridges would be swiftly and reversibly removed in order to eyeball the complications and treat them. Briefly, it was to prevent the implants from being hot, hidden and hazardous. Thus, the dental implants and its immediate surrounding tissues were made cool, accessible and therefore safe.
With the advent of mini implants, the principle of retrievability became a problem. The mini-implant was too small to fix a screw on and cementation would mean great difficulty in removing the crowns and bridges. Temporary cementation usually resulted in the crowns and bridges coming loose in a short time. Permanent cementation would mean having to cut through the thick metal of the crowns and bridges if there arises a need to retrieve them. The metal is thick because the mini-implants have small diameters and therefore a lot of metal and porcelain had to be used to bulk up the prosthesis to the correct sizes.
HISTORY AND PROGRESS OF MINI DENTAL IMPLANTS
Mini-implants alias small dental implants alias reduced diameter implants alias MOSTDIs were first used to stabilize dentures and transitionals while waiting for implants to osseointegrate. In recent years however, they are increasingly used very successfully in supporting crowns and bridges. If the trend continues, minis will become the main work horse in dental implantology. It is not inconceivable that in 10 years or so, dental implantology especially MOSTDIs will become a regular part of undergraduate dental training. (MOSTDIs stand for Minimized Osseointegrated Titanium Screw Dental Implants and for the purposes of this book we will mainly use this term from hereon)
This is because of the realization that dental implantology has so revolutionized every field of dental treatment, be it restorative, prosthodontic, endodontic, orthodontic, oral surgery, etc. Optimal dental care would not be complete without including dental implantology into the treatment planning. With MOSTDIs, dental implantology has become simpler, cheaper and with a much smaller learning curve than conventional sized dental implants, which we will refer from now on as COSTDIs. It must be added that MOSTDIs are also much more forgiving when complications arise because they are small and once removed, the bone and mucosa grow back much more rapidly than in the case of COSTDIs. (COSTDIs stand for Conventional Osseointegrated Screw Titanium Dental Implants).
The change will speed up considerably as prosthodontic solutions designed especially for MOSTDIs are invented and disseminated. In this book, I will present in some detail the possible prosthodontic solution for MOSTDIs that will keep the critical margins of soft and hard tissues around the neck of the implants cool, accessible and safe as opposed to hot, hidden and hazardous. This will also help to overcome the challenge of retrievability of crowns and bridges when MOSTDIs are used.
Hard tissue in implant dentistry refers to the bone. Generally, the bone in the maxilla is softer than the bone in the mandible. The hardness of the bone also varies within the same arch. The bone in the anterior of the maxilla is usually harder than that of the posterior and vice versa in the mandible. Hardness of the bone depends on bone density, i.e. the degree of calcification of the bone. Bone is divided into cortical bone that forms the outermost layer of bone which is hard and cancellous bone which is the bone encased by the cortical bone and is softer. The cancellous bone also varies in hardness within the same jaw. For the practical purposes of preparing the bone hole or osteotomy for receiving a dental implant, bone quality is classified into D1, D2, D3 and D4 bone, in descending hardness. The hardest is D1 and the softest is D4. The hardest will be more difficult to drill and must therefore be drilled slower with plenty of irrigation to prevent overheating the bone. The harder the bone will require the size of the bone hole to be closer to the size of the final implant, whereas in soft bone, the bone hole can be smaller.
Soft tissue in the mouth for the purpose of placing dental implants will refer mainly to the mucosa overlying the alveolar ridge where the missing tooth or teeth were. This mucosa will be usually attached mucosa in that the epithelium is directly attached to the periosteum of the bone. Attached mucosa is where it is advised that the dental implant should be placed so that it will most simulate the natural tooth and will be easier to clean. Unattached mucosa will be loose as there is a layer of connective tissue between the epithelium of the mucosa and the periosteum. A dental implant emerging through unattached or loose mucosa is thought to be more prone to plaque formation and more difficult to keep clean.
A preliminary assessment of the patient’s occlusion is paramount to the long term success of dental implants. Is the occlusion overclosed, open, deviating, have premature contacts? Is the patient suffering from bruxism. All these have to be considered together with the final treatment plan. The more teeth the patient has lost, the more important this process of treatment planning is.
Tuesday, July 17, 2012
THE BASIS FOR USING MINI DENTAL IMPLANTS
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:-
(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?
These reasons why 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 abutment with the connecting screw together 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 peri-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 can be designed to 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 osseointegrated implant. In fact, you cannot extract an osseointegrated 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 support it’s masticatory functions.
(4) Actually, it is the titanium oxide layer on both pure titanium and titanium alloy that is biocompatible and integrates and not pure titanium. Titanium, whether pure or alloy is covered with a layer of titanium oxide immediately on exposure to air. It follows then that both titanium and its alloy will 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. Why should’nt we, as responsible professionals, not 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 proven to be relatively pain free and heals rapidly.
(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, the tissue heals rapidly. The healing challenge to the surrounding tissue in the case of the conventional implant is much more and therefore 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 placed deeper and therefore longer than conventionals, thus increasing the 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.
Note: The actual surface area for all threaded screw implants will be 30 to 50% more than the figures above, taking into consideration that the surface of the threads will be more than that of a simple cylindrical surface.
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 with the threaded part 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.
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 Branemark 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 a well formed crater in the gums lined by healthy-looking pink mucosa, 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!