Implant Dentistry - Science topic

Mainly mini-implant success in orthodontics depends to a large extent on primary stability and bone structure at the insertion site. There are a host of factors responsible for success and failure of mini-implants, however the purpose of using a mini-implant will determine the location of the mini-implant. An important factor is the location of the mini-implant insertion. Most studies have found that palatal mini-implants have better success rates than other sites.

We can use different lines of protection to decrease exposure to covid 19 infection..

I mention it in my page on research gate as presentation ..ppt.. ..you can getback and read it carefully.

Best regard

Removing smear layers with Er:YAG to allow closer adaptation of fixture to bone helps with earlier integration and therefore allow earlier loading.

following

Yes

Prepare Models with deep flange impression trays to include maximum depth of mandible and reduce the dimensions of soft tissue to get dimensions of available bone at the minimum thickness of edentulous area

I suggest you to read our chapter, I wish your find it useful.

sure blood coagulation is important and but as Dr Elhadi said we have important thing will happen during ablation of tissue , photobiomodulation

and also remember that if you not use accurate parameters special with diode laser and co2 laser thermal damage id very dangerous for implant eosteointigration   

for that i recomended work in pulse mode with time off triple time on ( at least )

I may have been a little bit harsh in my previous comments. The Osstell  Device does a very nice job of identifying implants that lack high initial stability and then following those implants over time to demonstrate that either the lack of initial stability results in a biologic success as primary mechanical stability is replaced by secondary biologic stability and this can be easily calibrated with the implant stability quotient or it can identify implants that show a degradation in implant stability over time which means that an implant is not achieving Biologic stability and instead is experiencing bone resorption around the implant. Remember that at the interface of the newly placed implant in an osteotomy the bone will die back and be replaced by new bone if biologic stability occurs but if biologic stability does not occur the bone will dieback cannot be replaced in this results in a lower ISQ value over time.

The Osstell  Device can be used to demonstrate either the increase or the decrease in these values. So it's a good surrogate for positive implant performance assuming that the biologic numbers or the numbers recorded after a healing phase demonstrate a higher stability which will only occur if Biologic integration is occurring. This is definitely something of importance when we have very high insertion torque implants and we go to restore those implants definitively at an early time frame. Without a device like the Osstell we may well be measuring, or evaluating, implant stability with rather crude devices like a mirror handle tapped against the Implant listening for a sharp retort. Indeed an implant that is integrated will exhibit that sharp retort but it's also possible for an implant that is mechanically held relatively tighten the jawbone to also exhibit that sharp retort. Perhaps it's my ear but I cannot calibrate that ringing sound, that sharp sound, with such a level of precision that I can tell you whether that implant is going towards increasing biologic stability or is trending towards decreased biologic stability. When it's lost biologic stability I can tell you but I can't tell you if it is 10% up or 10% down. And remember, 10% down four weeks after an implant is placed is probably an indication that the implant is going to fail.

So the primary benefit of either of these devices is to use a more precise instrument to tell you which direction the stability is going. If it's going in the correct direction, increasing, we can feel pretty comfortable with that Implant. A device that accurately or maybe just precisely indicates the stability of the implant is certainly beneficial. Does it give me everything that I want, not yet, but that might be something that we need to determine over time. Perhaps there are new ways to utilize the equipment.

Perfect.

Really, everyday more and more cases we monitore and didn`t find answer for such changes. The progressive adjustment of occlusion associated to wear, also may cause vertical dimension reduction. I really agree that occlusal factors isolated can`t cause disease process.

Concerning to the method to oclusal adjustment, I think it is the more difficult point of discussion. We treat people. The perception is completelly subjective. Even when we use digital equipment or articulating paper, our feelling and the patient perception are  deteminant to estabilish the "correct" occlusion. We follow the academic principles, very well described above, but the "personal touch" is given by the professional perception.

When we look through the occlusal stand point, almost all single restoration will be transformed in a total rehabilitation, mainly in anterior cases when we look for mutually protected occlusion.

I attached main articles that show the surgical techniques related to increasing the amount of keratinized tissue around the implants by using free gingival graft. The other two articles show the the importance of increasing soft tissue thickness and the amount of keratinized tissue surrounding the implant.

Increasing soft tissue thickness and the amount of keratinized tissue surrounding the implant have recently raised an attention in Implant dentistry. Soft tissue thickness has a significant influence on marginal bone stability around implants. Linkevicius et al found that if the tissue thickness is less than 2 mm up to 1.45 mm of crestal bone loss might be anticipated, which can be avoided by increasing the tissue thickness to more than 2.5 mm. Thick vs thin biotype, represents thicker bony architecture with rich blood supply and vasculature and more resistance to bone loss at the time of inflammation.

Systematic reviews have shown that inadequate keratinized tissue around dental implants is related to more plaque accumulation, tissue inflammation, marginal soft tissue recession, and attachment loss.

First, you must determine the implant material has not been altered during the process of re-sterilizing, if so the results may be in question.

This was just in the news... it was in lettuce...but you know...

Dear Edres Ali

pls check the link.

There are many solutions which permit the use of implants even in the severely atrophic mandible, including submandibular cadaver grafting.

At Pi Dental center we have enjoyed great clinical success with over 42,000 Branemark external hex implants.  The external hex is more prosthetically friendly when using tilted implants, such as in the ALL ON 4 treatment concept.  It allows the angulated abutments more accurat alignment for prosthetic screw access.

It is also the best connection for zygomatic implants.

Load distribution is ideal with the external hex.

Complete and interesting information provided by Dr. Abu-Hussein Muhamad.

Dear Dr. Reyes,

I think that the recommendation that Dr. Nwhator gave is absolutely correct. You should do a Medline search which will generate a large number of "hits". Then you look at the  Titles and abstracts of these identified potential reference papers and you order the papers that are most relevant to your research question. You can order these articles from a medical library or you might be able to go into that medical library and make copies of the articles the old-fashioned way with a xerox machine.

You have to be aware that there are copyright laws to prevent distribution of articles even if you are talking to the original author of that article. If an author submits an article to a journal they give away the copyright to that article in that copyright is owned by the Journal. The abstracts are shared by the journals with Medline because it is in the interest of the publisher to gain interest in articles published in their journals. Distribution of free copies however would not be thought of as generally acceptable. There are exceptions, online full access journals  do exist. If the references that you are interested in are found in those journals you should be able to download those articles from  the Internet sites of those journals. In some instances you may have an electronic subscription to a specific journal which would allow you to download a specific article, one copy, but to ask for a blanket responsive receipt of free copies of articles on a specific topic is really not appropriate and would violate copyright law.

So  it comes down to your having to do the investigational work. You have to understand that  literature reviews are indeed secondary research and if you are interested in the results of secondary research you should be willing to make that effort. The task is to first perform the Medline search, this is called item generation, then you look at the titles and abstracts and eliminate the ones that are clearly inappropriate for the topic that you are trying to search, this is called item reduction but there are a number of steps to item reduction. Even after you read the full text article you might find in an article has no particular relevance towards your research question.  Honestly, this is the expectation in research. Anyone who has been involved in research can tell you that you have more dead ends then you have revelations. That should not stop you  from performing research but it is a recognition that you have to have.

No

It is not feasible at this point in time to re-sterilize this implant and then to insert it into another osteotomy. Contact of the implant with the environment will  alter the oxide layer of the implant and this will have negative effects on performance of that implant. I am not sure how things work in the rest of the world but in the United States there are virtually no implant companies that would not replace an implant that was contaminated during the time of surgical placement. So if you had three osteotomy's prepared and you contaminated one of the implants it was placed into one of those osteotomy's you would simply set that implant aside and open up a new implant to go into each of the sites.

If you are working with an implant system that does not utilize this approach, replacing contaminated implants, it might then be time to consider a new implant system with a more patient friendly policy.

Dear Dr. Saway;

A Maryland bridge would be better as it is fixed, so no chance of loss and also cheeper if you compare it with many time loss and fabrication of new ones.

Implants do not have 100% success...ten year data tends to show that success is possibly in the low 80%...why do you think we now see text books and articles published on dealing with implant failures...and how about those that are not in any report and the patient just has them taken out or the bone loss is so great they fall out. Remember, implants are evaluated as to survival not success or failure. 

Thanks Sir for opening a window about the anterior esthetic fixed appliance. I am performing such an appliance for children for whom & their parents the esthetic is of big concern. But what do you think about the effect of Nance on maxilla growth? 

Chair-side intra-oral pickup is such a simple and time saving technique with good serviceability, I used it in a study to pick up O-ring attachments for four implant retained maxillary over-dentures while patients were biting in centric.

The article that Dr. Toffoli provided does a nice job of comparing different implant surfaces but from what I am seeing in the article all the surfaces were prepared by the same manufacturer. Does this matter? Well other manufacturers would certainly say that it does matter. I think that if you talk to one company that makes or uses an SLA surface they will claim that their SLA surface is different than someone else's SLA surface. In the Coelho article I think, if I'm reading this correctly,  that all the implants were 6-4 alloys. You cannot make a Ti Unite  surface on the 64 alloy, that's what the materials folks have told me at least. The largest producer of SLA surface implants uses a grade 4 titanium commercially pure. So the fact that all the implants in this cited study were made with an alloy, the fact that they were all made by one manufacturer and the fact that they did not test Ti Unite may make the information gathered from this article less valuable to you as a reader or you may look at it and have it not change your opinion at all. This is a question of interpretation.

If we were to say that machine  turned implants, the first generation of implants that were to undergo osseointegration, were the implants that would have the lowest early bone to implant contact this would probably be correct. After a year in function it may not make any difference. In fact micro roughened implants probably make the biggest difference within the first two weeks after the implant was placed and it may have little impact long-term. So when you ask the question of which surfaces better the reality is that there are two viable answers. The first answer might be that in the, let's be generous, first month of the implant being in the bone that micro roughened implants probably recruit more cellular activity and have more early bone to implant contact. The second answer might be that after three years of function it doesn't make any difference.

Why do we want early bone to implant contact? Perhaps this is the most important question. Remember that osseointegration occurs if you are able to limit micro motion, according to Brunski,  to less than 100 µm. Cameron and Pilliar  Compared 150 µm of micro motion to 29 µm of micro motion  and found out that 29 µm allowed osseointegration to occur but  150 interfered with it. So somewhere between 29 and 100 µm is the amount of micro motion that would still allow osseointegration to occur. The reason that we use micro-roughened surface is because it should induce more early bone to implant contact which then means that you have less need for patient compliance. If we ask a patient to avoid chewing on an implant or to avoid use of a removable prosthesis that is placed over the top of an implant we have to realize that most patients are relatively compliant but some patients are not compliant at all. If we figured that the majority are are relatively compliant and we can cut the time during which they need to be compliant in half or in one quarter of the original time requirement we probably will have a slight improvement in the osseointegration rate.

So which is better? Better if we are defining more rapid integration we would probably be able to say that there are slight differences and in many instances those differences are probably more related to study design rather than true superiority.   Long-term, it probably doesn't matter.

Specific to the two surfaces that were asked about, neither of these surfaces should corrode with time. 

It all depends upon how you look at the question of maxillofacial rehabilitation.

Are you looking at situations where you are doing primary reconstruction? If you're doing primary reconstruction without an ora-nasal (meaning that the communication was closed surgically), or any other, communication and if you have relatively thin mucosa, in contrast to thick skin, implant should proved to be a great benefit in the reconstruction of the patient as you are trying to replace dental units (Teeth).

The thing that we have to be careful of however is the notion that teeth are involved in trituration but not in manipulation of the food bolus.(see Curtis, D et al). So if there has been A fundamental change in the anatomy of the buccal mucosa, buccal musculature, Hard or soft palate, tongue, Floor the mouth, etc. The issues related to manipulation of the food bolus are probably more critical than the patient's ability to triturate food. Manipulation of the bolus puts that bolus of food either on the occlusal table or fails to put it in a position where trituration would occur. The functional deficit in this situation is the poor manipulation of the food bolus more so than the poor trituration of the bolus.

If you are not looking at reconstruction of the defect but instead are looking at a communication between the oral and nasal cavities and you are using an obturator to close that defect the immobility of the implants is a bit of a disservice because the obturator generally does move, hopefully just a little, in function. The patient generally does not chew on the side of the defect but that doesn't mean but nothing ever goes on to that side. If I have my preference I would prefer retention of teeth to support an obturator because there is physiologic mobility which is then magnified by the length of the lever arm before you get to supporting areas within the defect such as the pterygoid plate.

If you're talking about a mandibular defect, Whether reconstructed or not, there is almost always some discrepancy from the normal, Let's call that the pre-surgical, condition. This generally means that if you are using implants there is a horizontal discrepancy in many instances that must be accommodated. Of course if the lateral border of the tongue was also resected, which happens frequently when a mandibular discontinuity defect is created whether it is restored or not, the question of manipulation of the food bolus comes into play once again.

The short answer to your question is that dental implants usually serve the valuable purpose in the management of a maxillofacial defect. The long answer however is that there are a number of new and different considerations that must be made when implants are used in the management of maxillofacial defect. The thought processes that we may have used 30 years ago may need to be rethought as we introduce a new components into the treatment armamentarium. Implants are often an acceptable root substitute but they are not always going to function in the same way as the natural tooth root and we need to be cognizant of this and must modify our treatment appropriately.

Here a study although with a small number of implants that covers an observation period of 10 to 20 years. Various reconstructions

 

Clin Oral Implants Res. 2001 Jun;12(3):252-9.

Long-term evaluation of non-submerged hollow cylinder implants. Clinical and radiographic results.

Merickse-Stern R1, Aerni D, Geering AH, Buser D.

Author information

 

Abstract

From 1974 various types of hollow cylinder ITI-implants were placed before the new generation of Bonefit ITI-implants was developed in the mid-eighties. The aim of this study was the clinical and radiographic evaluation of hollow cylinder implants that were inserted during the time period of 1978-1987 in partially and completely edentulous patients to support overdentures, fixed partial prostheses and single crowns. Altogether, 71 patients with a total of 132 hollow cylinder ITI-implants still in situ had been followed regularly during the entire observation period of 11.4 to 19.7 years (mean 14.1). Thirteen implants had to be removed before an observation period of 10 years was completed, 4 additional implants were lost after being in function for over 10 years and two further implants were considered to be failures at the time of the examination. Thus 91.4% of the implants were still in situ after 10 years and the survival rate for a mean observation period of 14.1 years was 84.6%. Periimplant parameters were used to assess the clinical conditions of the implants. On the radiographs, horizontal bone loss or angular defects could be detected on 40% of all implants if compared to the base-line situation. The probing depths around these implants were significantly increased compared to implants with an unchanged bone level, however the mean probing depths did not exceed 3.5 mm and 2.8 mm respectively. From this clinical evaluation one may conclude that with the early generation of hollow cylinder ITI-implants favorable long-term results were achieved.

Here another study with an observation period of 10 to 24 years with a limited number of edentulous patients having two interforaminal implants.

Int J Oral Maxillofac Implants. 2011 Mar-Apr;26(2):365-72.

Long-term results of mandibular implants supporting an overdenture: implant survival, failures, and crestal bone level changes.

Ueda T1, Kremer U, Katsoulis J, Mericske-Stern R.

Author information

 

Abstract

PURPOSE:

The present study summarizes the long-term clinical observations of edentulous patients treated with mandibular implant-supported overdentures.

MATERIALS AND METHODS:

From 1984 to 1997, edentulous patients were consecutively admitted to treatment with mandibular implant overdentures. The treatment plan was to connect the dentures to only two implants by means of single ball anchors or bars; in patients with special oral conditions, three implants would be placed. Regular maintenance care was provided at least one time per year. The cumulative implant survival rate was calculated. Implant failures were described according to clinical signs at the time of removal and related to the patient's specific history. Crestal bone measurements were performed using computer software.

RESULTS:

In all, 147 patients with 314 implants were evaluated for 10 to 24 years. Of these, 101 patients were still available; of the 46 patients who were not evaluated, 26 had died or were not ambulatory. Thirteen implants failed during the observation period, resulting in a cumulative survival rate of 85.9% after 24 years. The reasons for removal of implants were peri-implantitis (two implants) and mobility (11 implants). Mean crestal bone loss was 0.54 ± 0.7 mm per implant site after an average observation time of 16.5 ± 3.9 years. The duration of loading had a statistically significant effect on bone loss.

CONCLUSIONS:

The present data exhibit a satisfactory survival rate of implants. An individual analysis of implants with late failures did not reveal a typical failure pattern, but loss of implants without signs of infection was more frequent than loss of implants with signs of peri-implantitis.

Preimplantitis is the inflammation around implant and involves bone tissue. The possible bacteria that involve in such inflammation are red complex members such as Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola. These bacteria are strictly anaerobic. Thus to simulate such condition for in vitro we need to have life bone tissue and implant and the previous complex members and anaerobic condition for the growth and production of toxins that lead to inflammation of bone tissue around implant,

Certainly there is a slight change from the uncured and cured state, in terms of translucency. However, shade transition largely depends on the zone of application and layers applied. Shall look into the refernces and update soon.

Hi Alexandros, thank you for your answer. There are plenty of studies measuring the precision of io-scanners, since that is as easy as it is important to measure. The exactness of any relevant system on the market is (no longer) of any conercen, IMHO. BUT there are huge differences in the handling and workflow. And these differences matter to me as a clinician.

Hi Mohammed. I use the closed tray technique in the following clinical situations:

1. Single implants. 2. two non splinted implants (eg lower overdenture). 3.Limited mouth opening or implants located at the back of the mouth where long screws will not fit. 4. relatively parallel implants (no more than 2 though) and implants with their long axis parallel to the path of removal of the custom tray.

I use the open tray technique in the following clinical situations:

1. two or more splinted implants.2. implants with 15 degrees of divergence or more. 3.  immediate loading protocol.

Hope i answered your question sufficiently.Best regards.

You do not give enough information, but if you want to know how much excipient you must use in determinate formulation, I suggest you to consult the Pharmaceutical Excipients Handbook. It all depends on your formulation, if its is a Tablet, capsule, suspensión, injectable solution...etc.

There are clearly two camps.  One never splints to natural teeth and the other has no reservations about splinting to natural teeth.  

If you believe in splinting this belief is based upon a number of reports that suggest no problems with splinting.  If there is sufficient space between implant and tooth the movement of the mechanical connection to the implant probably compensates for the lack of a PDL...if too close together then the relative rigidity of the implant components means that the implant takes on the force from the prosthesis including the physiologic mobility fo the natural tooth retainer.

I belong to the camp that never splints the and implants.  The reason is that I am concerned about the rigidity of the implant taking excess force from the mobile natural tooth even if that tooth mobility is minimal.  I prefer to link similarly rigid implants to rigid implants.

Have I ever splinted implants to natural teeth?  Yes and anecdotally it did not work well most of the time so this is why I joined one camp.  Is there literature (mostly descriptive) suggesting that either approach may work?  Indeed there is but at this stage of my career I prefer to splint implants to implants and teeth to teeth but not to mix and match the two.

Dental Implants still follow concepts put forth by Branemark. Interesting thing about Branemark is that he was an Orthopaedic surgeon and the protocols that he instituted were based on the same principles of open joint surgeries and implants done in orthopaedics including the scrubbing, draping and isolation. While this is still important for oral environment, no matter how careful we are, contamination of the surgical site with saliva and the bacteria from saliva is inevitable.

Regarding the antibiotic prophylaxis prior to implant surgery or in the post procedure period, it is highly controversial. A few studies done in this regard concluded that post operative antibiotics would not be required. And that the standard surgical prophylaxis prior to surgery is all that is required. But interestingly some have questioned even the administration of pre procedure antibiotics. (more on this later).

For all practical purposes, I wish to state that while I have routinely seen antibiotics being administered after minor oral surgery by most dentists and even oral surgeons, I have not seen high level evidence supporting the same. Infact, most studies in this regard question the routine use of antibiotics after minor oral surgery. Any patient who is being planned for dental implant is being prepared for the procedure with oral prophylaxis and elimination of active periodontal disease before the procedure itself. In this regard, the oral cavity is presumably in pristine health. We do not use antibiotics even for placement of bone implants (post trauma) and haven't encountered any significant increase in infection rates. Post procedure antibiotics cannot and should not be considered a replacement for sound surgical technique and it cannot protect the patient against failure if the technique is erroneous.

Quoting from the article (1) attached :

"The use of prophylactic antibiotics prior to implant placement is controversial. A systematic review supports the use of 2 g amoxicillin as presurgical prophylaxis while a few other studies conclude that there is no added benefit. There is no evidence that implant failure is prevented by antibiotic usage"

The relevant references are also cited for your references. Though this is not exhaustive, the general recommendation will be that for a single site single implant placement, antibiotic prophylaxis would not be required considering that the entire surgical duration will be short and uncomplicated. For longer durations when the bone is expected to be exposed for longer durations or if combined with graft placements, prophylaxis may be considered but stress must be towards following all sterile precautions to prevent contamination of the surface of the implant for best osseointegration and for meticulous surgical technique with slow drilling combined with copious irrigation to prevent bone damage around the implant placed. These are far more important factors for implant success than antibiotics.

Irrational use of antibiotics should be avoided.

Regards,

Dr. Akilesh. R

India

There are rotary titanium brushes on the market that can be used.  There is a risk of removing thin bone around implants using these brushes.  IMHO, their effectiveness has not been fully evaluated.

It is also possible to use air jet polishing devices such as the Cavi-Jet which uses sodium bicarbonate.  Also, IMHO, their effectiveness has not been fully evaluated.

This is my personal opinion and not an official US FDA opinion.  Mention of any medical device by name is my providing an example and is not, and should not be considered an official US FDA recommendation.

Thank you.

An interesting  question about  a historic  approach . However,in my view,cross arch stabilisation is very much  yesterday's game.

There can be very little ,if any, justification now  for removing 62-73% of sound tooth tissue (Edelhof and sorenson 2002) for multiple preparations to provide one path of insertion for such prostheses.

The concept was founded on the   now discredited  idea that distributing  occlusal load across multiple teeth to provide rigidity  stopped periodontal disease.

Most of  have  not believed that for over forty years (Axelsson and Lindhe). Double abutting as a concept  can contain the seeds of  later failure due to pulpal or structural problems .Splinting teeth  for cross arch stabilisation also makes it more difficult for the average person to keep things clean -hence later failure.

Just ask yourself-"would I have that  destruction done to your own remaining sound teeth if you were missing those teeth"

hi ; Ithink that  this is a Straumann implant

like the one i am showing here which is an actual " Straumann implant"

hope that help

Cheers

prof galil

Thanks

Resorption patterns of buccal-crestal area in posterior make it difficult to locate appropriate place to put implant. So that I always use CBCT to measure the width and find out exact locations. In addition, if we have to do bone graft, there would be a lot of things to be considered. So in my personal opinion, panorama itself is not enough in many cases.

Now, the question that needs to be addressed is what do you classify as mini implants ?

Regular implants usually are 3.2 mm diameter or more. I am going on the definition that these mini dental implants are those that less than 3.2 mm. Also there are these narrow diameter implants of 1.8 mm diameter as well, which are also increasingly used.

The largest implant possible needs to be used. One benefit of implant supported denture is that the implant placement is not bound by adjacent tooth structure but by the bone support and vital structures (inferior alveolar nerve / mental nerve).

Mini implants are best used as temporary bone anchorage devices or for exceptional circumstances where the space is less for placement of regular implants either in height or in width. As for implant supported mandibular prosthesis, it should ideally be replacing a canine and / or a premolar tooth as these are the most common teeth used as tooth supported over dentures.

But 4 Mini Dental implants are being used for support dentures with success. So, why not ? This is not the ideal solution but acceptable compromise in old patients or in other patients who are not candidates for regular implants or in those who require grafts but cannot tolerate the procedure or refuse it. Even though the mini dental implants were initially used as temporary / transitional implants, increasingly we see them used long term as well.

They come cheap but they come in one piece! This means that if the ball attachment of the implant gets worn out in say 5-8 years, the entire implant will need to be replaced. In regular implants, only the prosthetic attachment (ball attachment) can be replaced. This is an important consideration. Removing an osseointegrated implant from the bone is not easy and even if it is done, there is considerable bone loss. So this aspect needs to be considered while using mini implants for removable complete denture support.

Regards,

Dr. Akilesh R

Consultant Oral and Maxillofacial Surgeon

Years ago I started looking into the FDA process that was required prior to the introduction of an implant into the marketplace.  FDA is said to protect the safety of the public and ensure effectiveness of medical devices.  At that point in time the FDA had all dental implants classified as as class 3 medical devices, the category that required the greatest level of scrutiny before a device could be sold in the USA.  On paper this meant that the implant manufacturer would have to provide a premarket approval (PMA) study or studies prior to marketing.  Interesting however is that the FDA has NEVER required a PMA for any dental implant system and has instead elected to accept a 510k documentation that basically says that the new device is substantially equivalent to a predicate device that was on the market on May 27, 1976 (if my memory of the date is correct) relative to safety and effectiveness. Please remember that in 1976 there was no "osseointegration" in the United States as the first US osseointegration studies began after 1982.  The Toronto replication study of the Branemark documents began in 1978 if my memory serves.  So FDA is only marginally helpful in demanding scientific evidence supporting any specific implant before it reaches the market.  This continues to be true today.

After that article I decided to look into the scientific documentation of dental implants that were either large market implants in the US marketplace or were ADA certified.  So we went to the companies and requested information from them to "validate" their implant systems and then we, as a process in our graduate program (prosthodontic and periodontology residents), reviewed the material supplied by  the manufacturers.  We did this in 1991 and 1996 (published in 1997).  This was around the time that we were first seeing EBD (evidence based dentistry) courses creeping into Prosthodontics which eventually began to gain acceptance in dentistry in general.  The study that we published in 1997 and updated in 2005 was NOT a meta analysis nor a systematic review, it predated both of these for dentistry although this sort of analysis was gaining in medicine at that time.

In 1997 we found a few implant systems that were documented sufficiently to allow our group to be confident in the use of these implants, by 2005 the number had grown.  Asbjorn Jokstad wrote an article in 2003 on the quality of dental implants in which he documented the number of implant designs worldwide that had actual scientific documentation...the number of documented systems was small while the number of systems in the market was huge.  Taking our work and Jokstad's work I think we can be comfortable saying that there are some documented implant systems but many systems are not documented by clinical studies and yet these non-documented implant systems are available in the marketplace.  Today there are large, respected companies that sell implants in their product lines for which there are few if any PUBLISHED studies to document the implants.  

I am not saying that undocumented implant systems are bad or that all documented systems are good but, for me, I like documentation.  There are some intriguing designs out there that might work really well, that might address issues that we are concerned with but many of these intriguing designs lack clinical cohort studies that show their clinical performance.  Does that worry anyone other than me?  I'm not sure.

I agree with Dr. Palaiologou, there are many to choose from.  I do caution however that some highly respected implant manufacturers have, from time to time, put out products without good research behind the products only to withdraw them at some point later because the promised or anticipated performance was less than expected.  Others have removed products that performed fine but were such small players in the market that the decision to pull the product was a financial one.

Indeed the manufacturers listed above seem to do well in general.  There are companies in every continent (except Antarctica) that have not been mentioned but still have good documentation and might be considered.  And there are companies on those continents that have products that have no documentation.

Wennerberg and Albrektsson have explained implant surfaces very well.  They have provided information that allow many people who are not materials scientists to better understand the science behind surface technology.

Indeed we will continue to see ongoing development and we need to remain vigilant in our assessment of the products that we purchase.  Indeed there is no perfect implant for all clinical applications so all we can do is read before we purchase and hope that we are doing the "right" thing when we change systems.  

The fact that many implants achieve osseointegration at a rate of 95-99% is impressive.  The question is whether osseointegration today remains as durable as it was in the earlier descriptions.  We hope so but there are few broad based long term studies to allow us to be truly confident in this regard.  My suggestion is that every clinician maintain a healthy skepticism about manufacturer claims, that they read scientific literature and that they constantly evaluate their own clinical experiences by recording all the implants they use into a spreadsheet so they can periodically assess their own experience and compare those experiences to published data to ensure that they are performing in a similar way while understanding that most published studies are efficacy studies rather then effectiveness studies and there is likely a difference between the two types.

Below are a few references to the comments above:

Eckert, S. E. (1995). "Food and Drug Administration requirements for dental implants." J Prosthet Dent 74(2): 162-168.

Eckert, S. E., Y. G. Choi and S. Koka (2003). "Methods for comparing the results of different studies." Int J Oral Maxillofac Implants 18(5): 697-705. 50.

Eckert, S. E., Y. G. Choi, A. R. Sanchez and S. Koka (2005). "Comparison of dental implant systems: quality of clinical evidence and prediction of 5-year survival." Int J Oral Maxillofac Implants 20(3): 406-415.

Eckert, S. E., A. Parein, H. L. Myshin and J. L. Padilla (1997). "Validation of dental implant systems through a review of literature supplied by system manufacturers." J Prosthet Dent 77(3): 271-279.

Quality of dental implants.

Jokstad A, Braegger U, Brunski JB, Carr AB, Naert I, Wennerberg A.

Int Dent J. 2003;53(6 Suppl 2):409-43. Review.

Near the end of the last century in the beginning of this one there were a number of anecdotal reports on implant fracture that seem to suggest that implant fracture was pandemic within the implant dentistry. Balshi et al and Eckert et al published two independent studies, retrospective K-series but both of the K-series were over 4000 implants, demonstratingA low incidence of implant fracture in a clinical practice were in two different clinical practices both with multiple clinicians involved in the placement and/or restoration of the implants. Both of those studies look at commercially pure grade 1 implants that were in the screw shape. The study by Eckert demonstrated a 0.6% incidence of implant fracture with more implants fracturing in partially edentulous jaws been in fully edentulism jaws

I think it is important to remember that cantilevers have been used and continue to be used but we need specifics regarding the application that is being discussed.  

The simple formula of quantifying the distance from the fulcrum line to the anterior abutment on a bilaterally supported full arch prosthesis and multiplying this by a factor seems to be comforting.  Charlie English suggested the factor of 1.4 (this is the smallest factor so this is why it gets quoted) but if the frame is made of a weak material (Grade 1, 2, 3 or 4 CP Ti) this might be too much cantilever.  With 6-4 alloy it might work fine if the connectors are large enough.  

When Charlie talked about 1.4 x the world was simpler.  Frames were bulky and the veneer was resin.  Today we need to fill in a lot more blanks before offering an opinion and then we qualify so much that it sounds like there is no answer.  

I think Dr Freedman is correct, a suggested parameter is a good thing, we just need topic a parameter that is truly safe.  I like the English factor and look at it as a default but I still do Ti 6-4 alloy frames  and the anterior abutment to fulcrum line is usually long.  So for me the risk is frame fracture and know that a long cantilever (even if the formula allows) will take its toll on the integrity of the frame if overloaded because there will be a high stress at the connector to the terminal implant because of the lever arm (moment of force).

The initial polymerization contraction is 1.5-3.5%, which causes problems with bulk fillings shrinking away from margins, but has little effect on layered build-ups. Wear resistance and flexibility are built into the composite, but do not necessarily directly relate to polymerization shrinkage.

I'm not that convinced. RFA has gray promise but it has consistently been inconsistent in establishing a specific point above which integration is almost inevitable and below which failure to integrate is a given. We feel good when the values are high but there should be some threshold and that threshold has yet to be established. Sadly RFA has been neither a positive nor a negative predictive factor especially as we compare different implant designs. Indeed RFA may be a good predictor of a design that is likely to have high initial stability in comparison to one that has lower initial stability (IOW, it is a design assessment) but design does not necessarily correlate with success.

The best resource I was able to find is : Impact of diabetes mellitus and glycemic control on the osseointegration of dental implants: a systematic literature review, J Periodontol. 2009 Nov;80(11):1719-30

Yes it is possible. It depends on the medium on which the laser beam propagates. Each medium can bear a certain density of power. If this density of power is exceeded, the medium is ionised in a plasma, this is called the "breakdown". In air, the maximal density of power before breadown is about 4 GW/cm². Below, there is a partial breadown. When the plasma appears, it block the coming photons and there is nore more energy deposited in the material. The plasma can even reflect the photons in the laser source and it is a possible crash for the laser. In water, the breakdown threeshold is about 8-9 GW/cm². See :

A. Sollier, L. Berthe, and R. Fabbro, Eur. Phys. J. AP 16, 131-139 (2001).

regards

Let's think about this a little bit. Our personal opinions are going to be based upon our own personal biases. Our biases are often dependent upon the clinical experiences that we have had. Indeed in this subject we have a few different categories of assessment of the occlusal vertical dimension. We often times assess this dimension on the basis of the vertical dimension of rest. The vertical dimension of rest is established through different techniques: radiographic, tactile, phonetics, aesthetics, etc. the vertical dimension of occlusion is usually some measurement closed relative to the vertical dimension of rest. It varies on the basis of skeletal jaw relationship with the largest differential being associated with a class II skeletal relationship in the smallest differential ring associated with a class III jaw relationship.

The reality is that we will never really be able to test this through a randomized controlled clinical trial. The reason for this is that an RCT is going to be influenced by the skills of the clinicians running the RCT. So if you have a clinician who is very good at the radiographic assessment of the analysis of the vertical dimension of Rest that individual may not be very good at assessing the tactile method of determining the vertical dimension of rest. Consequently the person who is experienced and skilled in the radiographic technique who then develops and RCT testing it against the tactile technique will undoubtedly find that the radiographic technique is superior. All the while another clinician trying to replicate the same results was experienced in the tactile technique would find opposite results. Remember that the RCT is an exquisite method of eliminating bias or reducing bias. The problem is that bias is not the only factor that relates to research evidence. We have issues of consistency, directness and precision. You might want to look at: http://effectivehealthcare.ahrq.gov/index.cfm/search-for-guides-reviews-and-reports/?productid=328&pageaction=displayproduct

So when you ask the question about our opinions on the best method to establish the clues of vertical dimension what you will receive is an answer based upon "our opinions" and those opinions are going to be very dramatically influenced by our experiences, our mentors, etc.

Ultimately I think that you need to, in my opinion, address this situation from a couple of different aspects. When I look at the occlusal vertical dimension I invariably use the tactile method and combine it with the phonetic method and combine it with aesthetics. After the cast are mounted I look at the parallelism of the ridges. I don't do electromyography and it is rare that I do radiographic assessment although I do this from time to time. So all this is important for me. It might not be of any relevance to you. The reality is that these are techniques and techniques are skill-based and experience-based, they will differ from clinician to clinician.

I think a lot will depend on the patient's compliance and his or her willingness to retain their natural dentition...as far as i am concerned i would definitely try 2 save the natural tooth instead of blindly going 4 implant....surgical crown lengthening, root canal treatment, post and core should be done but ultimately it all depends on the patient's will and whether they would be ready to come for so many appointments for saving a tooth..if the answer is no...definitely implant therapy..provided the periodontium is healthy and we have sufficient sound bone to receive an implant...

Yes platelet rich fibrin and platelet rich plasma have been extensively used in periodontal regeneration and excellent results have been achieved.The newer of the two, that is PRF has tremendous potential as it harbours lot of growth factors and are used even by oral surgeons in dental defects.Hence it makes a lot of sense to use them in regeneration procedures n dentistry.

I think the first step is to diagnose the problem. (Isn't this always the case?)

Was the implant placed too far to the labial to be covered by soft tissue?

Was the implant platform placed above the level of the osseous crest?

Was the implant placed in the correct position and then bone loss and soft tissue loss occurred?

The first two have no great solutions. The third problem is usually bone loss prior to soft tissue loss rather than soft tissue loss causing the bone to be lost.

Evidence for re-integration of a surface of an implant where the bone has been lost is weak. Perhaps one might suggest that it is beyond weak and there is almost no evidence for re-integration other than in animal studies where the bone was lost secondary to ligature inducement...most severe in coated implants (HA, TPS) and regrowth was best with coated implants. But this is old material.

Assuming that tissue follows bone, once the bone level is reduced secondary to bone loss then the soft tissue will usually also be lost. Gain of soft tissue with grafting over an avascular implant surface is unlikely unless there is a very narrow fenestration and then the soft tissue gain will not be thick or durable...it is likely to be lost again over time.

This is why clinical and radiographical follow-ups are so important in my opinion. If you chose to put implants in a KCOT-free zone and the implants osseointegrate, then close follow-up will allow you to act quickly in presence of a new KCOT before it compromises the osseointegrated implants.

In this end, it's all a matter of weighing the risks for the patient.

This is not a new topic although I agree, most clinicians seem unaware of the possibility of such anatomic variants.

The real question is whether such anatomical distribution affects local anesthesia.

In a review of 2006, accessory innervation from the cervical plexus was listed as a possible cause of anesthesia failure (Boronat & Penarrocha 2006).

I have personally encountered a few cases of such suspected innervation that could be circumvented by local application of anesthesia in the first mandibular molar region.

Boronat A, Penarrocha M. Failure of locoregional anesthesia in dental practice : review of the literature. Med Oral Pathol Oral Cir Bucal 2006 ;11 :E10-3.

Dear Maria,

yes, I do clearly agree with the article.

The problems we face in dental research are very scarce budgets when compared to medicine. When you do not have money for your research you can hardly engage in high level studies, add of statisticians, extended ethical approval, etc.

Evidence currently gives dental research and systematic review poor marks!

Actually there is no fixed answer for your question. Let me tell you some facts:

1. Bone doesn't grow around implants but it joins titanium in a chemical reaction called osseointegration.

2. We may load the implant immediately after surgery or we may postpone loading (tooth fixation) for up to six months.

3. It depends on the drilling of the implant bed into the jaw bone as well as the amount and type of bone you have.

4. Size and length of the implant is an important factor too.

5. Healing capacity of your body is an important issue.

Finally, your dentist (the one who put the implant) is the only person who can answer your question.

Actually, I am in complete agreement with Dr Agrawal in that bone formation and resorption are a continuous and coupled process. Nevertheless, salivary levels of sRANKL and OPG, more importantly assessing their ratios at different times might provide an insight into the healing. We now have really sensitive ELISA tests that can measure the levels of these substances in saliva upto a few picograms. Matrix Metalloproteinases especially MMP8 and 10 could also be looked into as potential candidates for determining the phase of tooth movement.

I would suggest so to go through the high-cited article: Occlusal considerations in implant therapy: clinical guidelines with biomechanical rationale (Kim et al. 2005 COIR). Hope this may be helpful for you

Thank you Aberto,

This is a very interesting answer. I also agree in that implant angulation taking care not to entry in the orbital cavity and assuring a good stability in the malar bone should be the main goal. Pre-op virtual planning would be a good choice if some anatomical landmarks are fixed for translation into the surgical field.

Dear all, it is clear that what Dr. Lee proposes in its research should be the gold standard for measuring resorption of bone grafts after implant placement. However, the histologic study of bone grafts sections together with the inserted implant is not reliable in clinical practice. Alberto, I agree with you in that measuring distance from the top of the screw should be appropriate enough to control bone resorption, at least in the bucco-lingual direction. Although an immediate post-op CBCT should be more accurate for comparison with delay CBCT, it is not always routinely performed. Go ahead with your clinical research. I would focus on onlay grafting for the anterior upper maxilla.

Dear Alberto, it is a fact that, at the state of knowledge, the absence of an universally accepted measurement method, able to assess the degree of defect correction and the three-dimensional stability over time of the augmented bone, still prevent clinicians to draw significant conclusions about the long-term clinical success of the different augmentation procedures.

Of course, neither open flap caliper measurements nor CT scan can be considered feasible routine methods of monitoring bone stability over time, because of their unreasonable economical and biological costs.

I fully agree with Dr Kashi that “bone sounding” is the technique with the best cost-benefit ratio, but - as rightly pointed out Dr Nakamai about the angulation of the caliper- the reproducibility of position may be an issue, for any chosen instrument for measuring . This problem - for bone sounding - may be partly overcome by using a template customized on the basis of final restoration and pierced at some buccal and lingual/palatal points at each implant site. In this way the holes guide the endo files during bone sounding in a reproducible position and angle, allowing the long-term evaluation of the horizontal stability of the augmented bone.

In this regard, if you think it might worthwhile, please view the article

Horizontal and vertical ridge augmentation in localized alveolar deficient sites: a retrospective case series. Implant dentistry. 06/2012; 21(3):175-85

available at : https://www.researchgate.net/publication/225054009_Horizontal_and_vertical_ridge_augmentation_in_localized_alveolar_deficient_sites_a_retrospective_case_series

Dear Ahmad

I recieved arequest from you asking for a copy of my publication: indirect sinus floor elevation for osseoitegrated dental implants, published in JOI . pls send me your private mail adress to send you a PDF file. I'm not allowed to upload the file to a third party web site.

my mail is

Considering fixed prosthetic restorations, you can see these two:

Int J Prosthodont. 2011 Jul-Aug;24(4):294-302.

Immediate versus delayed loading of dental implants in edentulous maxillae: a 36-month prospective study.

-Tealdo T, Bevilacqua M, Menini M, Pera F, Ravera G, Drago C, Pera P.

Clin Oral Implants Res. 2008 May;19(5):433-41. Epub 2008 Mar 26.

Five-year results from a randomized, controlled trial on early and delayed loading of implants supporting full-arch prosthesis in the edentulous maxilla.

-Fischer K, Stenberg T, Hedin M, Sennerby L.

as regards overdentures, please find these other two but the loading is early, not properly immediate

- Turkyilmaz I, Tozum TF, Fuhrmann DM, Tumer C.

Seven-year follow-up results of TiUnite implants supporting mandibular overdentures: early versus delayed loading.

Clin Implant Dent Relat Res. 2012 May;14 Suppl 1:e83-90. doi: 10.1111/j.1708-8208.2011.00365.x. Epub 2011 Jul 11.

-Mackie A, Lyons K, Thomson WM, Payne AG.

Mandibular two-implant overdentures: prosthodontic maintenance using different loading protocols and attachment systems. Int J Prosthodont. 2011 Sep-Oct;24(5):405-16.

I personally do not know any other

Well, I would discuss this question from anatomical point of view. The ratio of compact bone to that of spongy bone in ramus block graft may be different from that of calvaria block grafts. This might affect the ISQ of dental implants.This if we exclude the accuracy of statistical analysis used.