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Is Smoking Really That Bad for Dental Implants?

How your patient’s smoking habit can sabotage your dental implant surgery and what you can do to still succeed.

No implants for smokers?

You’ve probably heard or read that smoking can be a risk factor for dental implant failure. But does that mean that you will turn away someone who smokes, telling them that they are not a candidate for dental implants?

Are you 100% sure that smoking is a risk factor?

Recently, I had a dental student tell me that smoking is NOT a risk factor for implant failure because of some study that showed that there was no difference in the success rates. I was doubtful, but I checked his reference and…he is right!…sort of.

This article will first describe the biology of how smoking affects bone repair, then briefly cover what the literature says, and finally provide some clinical suggestions for how to modify your treatment.

The Biology Behind it All 

Angiogenesis and osteogenesis are essential to successful osseointegration of a dental implant.

It’s easy to understand why angiogenesis is important. The growth of new blood vessels brings oxygen and growth factors into the implant site, thereby facilitating healing.

It is a well-documented relationship:

Enhanced angiogenesis will lead to enhanced bone healing while inhibited angiogenesis will impair bone healing.

So do you think smoking enhances or inhibits angiogenesis?

According to a study by Ma in 2010 (they performed distraction osteogenesis on poor little rabbits!) smoking actually increased angiogenesis. (My mind was blown!)…but, at the same time, smoking also reduced blood flow.

More blood vessels but less blood flow? This was their hypothesis:

  • Nicotine causes vasoconstriction which decreases the delivery of blood to capillary beds, leading to tissue hypoxia.
  • This oxygen deprivation stimulates the creation of more blood vessels.
  • While there may be more blood vessels,  the vasoconstrictive effect of nicotine does not allow this increase in blood vessel density to lead to a higher blood flow.

Just as important is the role of Bone Morphogenic Proteins (BMPs), which are the main osteogenic factors in the body. This study by Ma also showed that nicotine had an inhibitory effect on BMP-2, thereby, inhibiting osteogenic activity.

So smoking basically cripples two of the most important processes in osseointegration: blood flow and growth factors.


Notice the suppressed expression of BMP-2 for the nicotine group.


But Does it Really Make a Difference?

Remember about the study my student was telling me about? It was written by Wang et al in 1996. They found that success rates for dental implants in smokers and non-smokers were the same.

How could smoking not matter? This contradicts all of this biology we just read about.

It turns out that this study had many limitations that should cause us to take it with a grain of salt:

  • Their sample size was small
  • They only followed up the patients for 36 months
  • They only placed the implants in loose trabecular bone

Not that we should dismiss their findings, but we should view them in the context of a broader review of the literature.

What’s the Literature Say?

A review by Chrcanovic(2015) and another by Klokkevold (2007), help us to demystify what is really the deal with dental implants in smokers. These are the golden bits of information I pulled out of these articles.


  1. Does promote greater marginal bone loss.
  2. Does not have a big effect on implant failure in good bone sites.
  3. Significantly increases failure risk in poor bone sites–especially evident over longer periods of time.
  4. Increases risk of post-operative infection.

The Clinical Applications

Because we know that smoking will cause more marginal bone loss, we should take extra measures to maintain bone. Maybe we should be more likely to recommend socket grafting after extractions as well as ridge augmentation during implant placement when indicated.

Because we know that smoking does not have a huge impact on good bone sites, we generally should not be worried about implants in the anterior mandible and, all things equal, we can treat them the same as in a non-smoking patient.

As the bone quality decreases to include more porous bone, it would be prudent to get a little more paranoid and cautious. While immediate placement might still be reasonable in some special situations in the esthetic zone,  perhaps we should shy away from immediate placement as the bone quality decreases.

Remember that one way to assess bone quality is via a bone density assessment from a Cone Beam CT. (See: Hounsfield Units for Implant Surgery)

Also, because smokers are at a higher risk for post-operative infection, it would be wise to closely follow them during the healing period. Perhaps, you may want to emphasize the importance of a one-week follow up visit as well as diligent compliance with proper oral hygiene.

I personally, will definitely not be looking to immediately load anything. (except for full arch prostheses because of the cross-arch splinting effect) I know everyone says they do it all the time and have marvelous success, but I am a strong believer in taking every opportunity possible to incrementally improve the outcome. I think that delayed loading protocol in smokers can improve the overall success rate.

Finally, there is one article by Bain, that reports significantly increased success rates in smokers when followed a protocol of smoking cessation 1 week prior to implant surgery and for 8 weeks after.

While your patient’s smoking habit can work against you, by understanding the risks and then managing them accordingly, you can place implants confidently in spite of this risk factor.

Coming up:

Subscribe to the blog (upper left on desktop, below on smartphone) to stay tuned for upcoming articles in “Learning to Fail.” We will cover:

  • treatment options for the compromised implant
  • risk factors you should memorize
  • clinical examples of some interesting failures
  • video interview on failure with leading implant surgeons


Ma Li et al. Uncoupled Angiogenesis and Osteogenesis in Nicotine-Compromised Bone Healing. Journal of Bone and Mineral Research, Vol 25. No. 6, June 2010.

Ma Li et al. Influence of nicotine on the biological activity of rabbit osteoblasts. Clin. Oral Impl Res. 22, 2011; 338-342. 

Wang IC, Reddy MS, Geurs NC, Jeffcoat, MK. Risk factors in dental implant failure. J Long Term Eff Med Implants. 1996;6:103-117.

Chrcanovic, Bruno et al. Smoking and dental implants: A systemic review and meta-analysis. Journal of Dentistry 43(2015)487-498.

Klokkevold Perry, Han Thomas. How do Smoking, Diabetes, and Periodontitis Affect Outcomes of Implant Treatment? Int Journal of Oral Maxillofacial Implants. Volume 22, Supplement, 2007. 

Bain CA. Smoking and implant failure–Benefits of a smoking cessation protocol. Int J Oral Maxillofac Implants; 11:756-759.

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Learning to Fail: Defining Failure


It’s not if, but when.

Everyone who works with dental implants will find themselves here at some point. The implant site shows some ominous signs–bone loss, bleeding on probing, exudate, or maybe even mobility (gasp!!)…and it is unclear how to proceed.  

Looks borderline. Is it failed? Or still ok?


This series of posts will be dedicated to learning to manage implant failures and to use them as a way to improve yourself as a dental implantologist.

Rather than sweeping them under the rug, let’s value them as rare and treasured learning opportunities.

Necessary Conditions for Success

Let’s take a quick, high-level view at some of the conditions that we need for our implants to thrive. (We’ll take a closer look later)

First, when the implant is placed into the preparation, it should be surrounded by bone and completely immobilized.  (Remember we previously discussed what insertion torque is best)

Second, a blood clot must form between the implant surface and the preparation.

Third, the patient’s body develops vasculature in the site and sends in growth factors and osteoprogenitor cells. This allows bone to gradually be deposited on the implant surface.

Finally, the bone around the implants constantly remodels depending on its surrounding conditions. In a healthy implant, the fixture and prosthesis allow for a favorable homeostasis between the implant and bone.

Why You Will Fail

There are several things that can prevent you from achieving this homeostasis. We’ll discuss them at length in the upcoming articles in this series, but here is a quick list:

  • Surgical blunders
  • Compromised healing
  • Infection
  • Occlusal Trauma
  • Poor bone quality or volume

Did my Implant Fail?

Implant outcomes come in all shapes and sizes. This goal of this introductory post is simply to establish a framework to help categorize your implant outcomes.

 Let’s look at this set of criteria that was established by the International Congress of Oral Implantologists to help us add some structure to our failures. 

They categorize implants into 4 broad categories: Success, Satisfactory survival, Compromised survival, and Failure. Here is a quick description reference for each category.

ICOI Classification

  • Success
    • No pain/tenderness on function
    • No mobility
    • <2mm of radiographic bone loss after placement
    • No Hx of pus
    • Patient and dentist satisfied with esthetic outcome
  • Satisfactory Survival
    • No pain on function
    • No mobility
    • 2-4mm of radiographic bone loss after placement
    • No Hx of pus
  • Compromised Survival
    • May be sensitive on function
    • No mobility
    • Radiographic bone loss >4mm (less than half of implant body)
    • Probing depth >7mm
    • May have Hx of exudate
  • Failure
    • Pain on function
    • Mobility
    • Radiographic bone loss > half the implant body
    • Uncontrolled exudate
    • No longer in the mouth

Compromised or Failure?

In the absence of mobility, many of us struggle (at least I do) with deciding if a suspicious implant falls into the “compromised survival” or “failed” category.

The answer is not always clear. Sometimes this “borderline” implant will be treatable, and others it will continue to go downhill. Some things to consider in this case are:

  • Are you able to resolve any exudate?
  • Is the bone loss occurring very quickly or gradually?
  • Can the restorative plan be altered to improve the overall outcome?
  • What are the patient’s preferences?

Remember, uncontrolled exudate classifies the implant as a failure and indicates removal based on the ICOI guidelines. The answers to the other questions can help you steer towards the right choice for your patient’s overall well-being.

Now that we have:

1) An idea of  what factors are playing a role in success v. failure, and

2) A simple classification system to guide us,

…we’re ready to start looking at some specifics, in the next post.

Do you have any  ‘borderline’ failures and are unsure of how to proceed?  I would love to hear about your case. By sharing your cases, we can all learn from each other’s experiences!

Coming up:

Subscribe to the blog (upper left on desktop, below on smartphone) to stay tuned for upcoming articles in “Learning to Fail.” We will cover:

  • treatment options for the compromised implant
  • risk factors you should memorize
  • clinical examples of some interesting failures
  • video interview on failure with leading implant surgeons



Misch CE, Perel ML, Wang HL, Sammartino G, Galindo-Moreno P, Trisi P, et al. Implant success, survival, and failure: The International Congress of Oral Implantologists Pisa Consensus Conference. Implant Dent 2008; 17:5-15.

Beumer J, Marunick M, Esposito S. Maxillofacial Rehabilitation. Hanover Park: Quintessence. 2011.

Froum, Stuart. Dental Implant Complications.: Etiology, Prevention, and Treatment. New Jersey: Wiley & Sons. 2016. Electronic copy.

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Oh Snap! Perforated the Sinus during implant placement

How maxillary Sinus Membrane Perforation Affects Implant Survival and What You Can Do About It

Does Sinus membrane perforation mean lower success for implants?

We all know that one of the main components of implant placement is to measure the amount of bone height before implant placement in the posterior maxilla. But what happens if a maxillary sinus is perforated anyway during implant placement or sinus membrane elevation? Does this mean that mean your procedure is a failure? Continue reading Oh Snap! Perforated the Sinus during implant placement

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Placed dental implant too close to the IA Nerve!

“Help! I placed a dental implant too close to the IA nerve!”

This is not an uncommon thought for a dentist placing dental implants in the posterior mandible. Sometimes, it is not clear on the panoramic image exactly where the Inferior Alveolar nerve is. Other times the patient may jump up in the chair when you are only a couple of millimeters deep.

It is a commonly accepted best practice to maintain a distance of at least 2mm away from the IA nerve when placing implants. But what if:

  1. You re-evaluate the radiographs later and begin to wonder if you are too close to the nerve
  2. Your patient calls you and says they’re feeling pain in that area
  3. Your patient says their lip is numb even though you have only provided local anesthetic infiltrations

It makes you think twice and maybe loose some sleep over it. Here’s a protocol by Jacobs (2000) you can follow to give you a systematic approach to solving these issues.

If you suspect nerve damage [or pretty much for all cases] call the patient after 6 hours to see how they are doing. Check if they’re experiencing any symptoms of nerve damage. Soreness and some pain is obviously normal, but if they felt burning or persistent numbness — consider taking a post operative CBCT.

Evaluate the CBCT and determine if it is indeed encroaching on the nerve (closer than 2mm). If so, within 36 hours, back the implant away from the nerve to re-establish your safety distance of 2mm.

This 36 hour hour window appears to be important because backing an implant out after this timeframe does not appear to help and may even complicate matters.

If the implant has been encroaching the IA nerve space for over 36 hours, it is possible that some permanent nerve damage has occurred. To manage symptoms of pain in this situation, Jacobs recommends topical anesthetic mouthwash (15% benzocaine/1.7% amethocaine) followed by topical capsaicin treatment twice daily for a 4 week period.

In the posterior mandible, whenever there is any doubt at all I am using a CBCT to get some exact measurements. If you are having a difficult time monitoring the depth of your drills, you may want to invest in some drill stoppers (Salvin offers a Universal Drill Stop).

Hope this helps.





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How to convert an All-on-4 Immediate Load Denture

All-on-4 Denture conversion

Hey guys,

As promised, here is the step-by-step walkthrough of converting an All-on-4 denture. In my upcoming ebook, The Implant Ninja All-on-4 Handbook, I will cover this process in more depth and will discuss different approaches & materials, and most importantly, complications. (It will become available in Spring 2017. Pre-order to reserve your copy! )

If you’re interested in learning my technique, we are also offering All-on-4 learning webinars as well as a training program called “All-on-4 in a Box” which is offers distance learning using a hands-on kit that is mailed to your office.

This is the patient’s pre-op presentation. He had an old partial denture that was retained by a ball attachment inside of the canine root. (I have extracted a lot of teeth with these types of attachments as they commonly decay from the inside.)

Nice thick alveolar ridge. It looks like this procedure will be a piece of cake. One of my main concerns here is that he will break the future prosthesis. Look at the risk factors:

  1. His upper denture is worn down
  2. His lower remaining teeth are worn
  3. He has a lot of bone height which means limited inter-arch restorative space.
  4. He is a stalky guy with thick masseter muscles (although you can’t see this here)

The teeth were extracted easily. Then I started placing the anterior implants. I start with these because this area is easier to access and visualize. I begin with using a narrow pilot drill.

I begin by using a narrow pilot drill at the #27 site. Before I drill, I have the upper denture in place to give me a reference for my angulation. Also, I try on mandibular duplicate denture that was made in clear acrylic. This will give me an idea of how to angle the implants so that I do not have the screw access coming out of the facial aspects of the teeth.

Then I proceed to use the narrow pilot drill at the #22 site. I then take the drill off of the handpiece and insert one drill in each osteotomy. This allows me to gauge the parallelism and the angulation when compared with the upper denture.

Then I proceed with the 2mm twist drill in both of these sites, which allows me to then place the paralleling pins inside the osteotomy. Once I am happy with their positioning. I proceed with an additional implant at #24 site.

This is a picture with all 3 paralleling pins in place:

Once all three implants in the anterior region are placed, I proceed to preparing the posterior sites. When there is limited bone height, I use the tilted protocol for the distal implants. However, there is plenty of bone above the IA canal, so I place axial implants in all of the positions. This makes everything so much easier. There is no need to tilt implants just for the hell of it.

After that, the posterior implants are put into place. You can see in the above picture, that I use the implant transfer driver as a paralleling tool after the implant has already been placed. This is very useful.

Once All of my implants are positioned where I want them, I placed 2.5mm tall straight multi-unit abutments. In this case, I used a kit from Implant Direct called Simply Fixed. Each pack costs $200-230 and comes with an implant analog, temporary titanium cylinder, multi-unit abutment, comfort cap, and impression coping. As far as convenience goes –it’s hard to beat that!

Then, I place the comfort caps on the multi-unit abutments and suture up my flap. I like to use interrupted sutures. In this case I used catgut 3-0.

Next, I placed blue mousse inside the intaglio of the mandibuar denture, seated it on the ridge, and have the patient bite down into occlusion. This provides an index of the implant positions. I use a football acrylic bur and just make a hole right through the denture in each of those locations.

I took off those comfort caps and placed multi-unit temporary titanium abutments on each implant.

I check that there is clearance between each cylinder and the denture. This clearance is important because it will provide access for me to inject an acrylic pick-up material. In the following picture, you can see that some of the titanium cylinders are binding so the denture still has to be adjusted. Also, now is a good time to see if any of the cylinders protrude through the denture and will interfere with occlusion. If so, make sure to cut them down a little shorter.

Now that there is enough clearance and I am happy with the occlusion, I will punch some holes into a rubber dam and slip that over the cylinders. The purpose of the rubber dam is so that 1) acrylic doesnt seep into the wound and 2) the acrylic does not harden around the sutures and rip them out when I remove the denture.

I place teflon tape inside of the access holes to make sure that I don’t get any acrylic inside the cylinders and make a huge headache for myself.

I mix up some acrylic in a medicine cup, quickly pour it into a Monoject syringe and squirt it around the titanium cylinders. For this case, the acrylic I used was Jet acrylic. However, I also really like a super-fast set acrylic called Unifast Trad. (This acrylic is crazy fast set, so if you’re just starting out, I would not recommend it) Some colleagues have mentioned that they use Locator Chairside Processing Material to attach the cylinders.

Upon reading this article, my U Mich Prosthodontics buddy, Dr. Kevin Aminzadeh mentioned that he also places some buccal injection holes at the cylinder site. This will help prevent some major voids at the base of the cylinder. (Thanks for the tip, Kevin!)

I do this for each one of the implants. Make sure your patient bites down into occlusion as soon as you are done injecting acrylic. This will make sure vertical dimension and occlusion is correct.

As the acrylic material hardens, it gets hot so I squirt a little bit of water over the acrylic to avoid burning the patient. After the material is set, I remove the teflon and unscrew each abutment.

Now I fill the voids around the titanium cylinders in the intaglio surface with more acrylic. After the voids are filled and I am 100% comfortable with the fit of the titanium cylinders onto the abutments (sometimes the cylinders move and it can become a mini-nightmare to manage it) I will proceed to cut off the flange, cut off the tooth distal to the last implant, and trim polish the denture.

Here is the converted denture in place:

I cover up the access holes with teflon tape and put composite over them.


Do you use different methods for converting All-on-4 dentures? I would be happy to hear about it!

Subscribe to the blog to stay tuned for the upcoming ebook: “The Implant Ninja All-on-4 Handbook.”



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All-on-Four Complications: Part 2


This is a continuation of The All-on-Four Complications Part 1. Again, I’m not writing this to scare you off from this treatment. I am not saying that I don’t believe in this treatment. On the contrary, I think it is a fantastic solution.

However, I would like to shed some light on some of these issues which are not regularly discussed in an open forum. By sharing these limitations, we can push past them and deliver improved treatment protocols for our patients.

(By the way, to learn how you can make All-on-Four Prosthetics & Manage common complications, see our online training course All-on-Four “In-A-Box”

Hygiene Issues

Hygiene can be horrendous under these prostheses. Some patients just don’t have the manual dexterity or appropriate hygiene habits to keep these prosthetics clean. It used to be thought that calculus and plaque did not negatively affect the implants, but we know that good hygiene is necessary for good peri-implant health and longevity.

See how red the tissues are under the lingual of this prosthesis:


The intaglio surface was relieved and the patient was instructed to use Go-Between brushes as well as a Waterpik to clean under her prosthesis. I also like the brushes called “Plackers” or “Tepe Brushes” which have right angles to make posterior regions easily to clean.


This temporary All-on-4 conversion prosthesis has the worst hygiene I’ve ever seen:


It is important to ensure that the intaglio surface contacts the ridge in a rounded pin-point contact so that food does not lodge itself in there.

Questionable Implant Healing Prior to Loading

Sometimes an implant gives us some trouble before the final prosthesis is delivered. In these cases what do you do? You obviously can’t deliver a prosthesis on a potentially unstable implant. When I see an implant that exhibits peri-implant mucositis or peri-implantitis under an All-on-Four, this is what I do:

  • Treat the peri-implant infection/irritation with mechanical debridement and antibacterial protocol as indicated. (This is for another article)
  • Place another implant adjacent to this area at no additional charge
  • Allow the patient to heal up for a while longer while the new implant ossseointegrates.
  • Finally, assess the original implant and new implant before proceeding to final prosthesis.



In this next case, when I sent my case for finish, the laboratory sent me back a prosthesis with a crack at one of the access holes. This would have been bound to have caused me trouble so I sent it back for repair.


Visible Transition Line

Before placing dental implants, it is important to assess the transition line. Before implants are placed: Are the patient’s gums visible when they smile? If so, they will require a tooth-only prosthesis in order to have a natural emergence from the gums. Alternatively, the patient can have selective alveolectomy to make the gums less visible. In some situations, a prosthesis may have a very minor facial flange (emphasis on minor!) to hide this unesthetic transition. This is discussed in detail in my article on Lip Support. 


Non-Passive Fit

Passive fit is important for the longevity of the prosthesis. This patient had a screw fracture at this implant site. When a radiograph was taken, this is what I saw:


Definitely not what you want to see under your prosthetics. In residency, we would often start these cases over from scratch. However, in the real world people have more realistic expectations and are not as willing to go without teeth. In this case, the prosthesis was sectioned, the framework was laser-welded and the acrylic was repaired. The process is shown in the following pictures:

_mg_1764 _mg_1765 _mg_1789 _mg_1809 _mg_1812_mg_1759

Anterior Teeth Popping-off

When posterior support becomes compromised by wear or fracture, the anterior teeth begin to occlude harder. This commonly leads to anterior teeth popping off.


Acrylic Wear

Finally, this is one major problem we see with acrylic prosthetics. However, not all patients will end up like this. It depends on individual patient factors, specifically clenching and teeth-grinding habits. To slow this process, a night guard is absolutely, 100% necessary after All-on-4 Treatment. Another approach that I have seen is to make onlays over the molars on the All-on-4 prosthesis–but these are at risk for popping off and they may actually make the prosthesis more prone to fracture.



To learn how you can start making All-on-Four Prosthetics for your patients and how to avoid the common complications, see our training course All-on-Four “In-A-Box”.

Subscribe to my blog (on the left or down below!) to stay tuned to more articles and pictures of interesting cases.



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All-on-4 Complications: Part 1

Full Arch implant bridges (All-on-4, permanent dentures, etc) are a wonderful thing. They quickly turn around a patient’s self-confidence and get them back on track with their diet and overall health. I have had a very positive experience providing my patients with this treatment.


if done the wrong way, they can lead to pretty disastrous outcomes. Although failure of osseointegration of dental implants does sometimes occur, is not the major complication for these cases. Rather, the nuisance really is managing prosthetic complications. (To learn how you can make All-on-Four Prosthetics & Manage common complications, see our training course All-on-Four “In-A-Box”)

Here are some common issues that are encountered with All-on-4 treatments:

Fracture of Temporary All-on-4 Restoration

This fracture occurred months after immediate loading right around the titanium temporary cylinder where the denture was ground-away during the conversion process.


The following is a video of the distal portion of an All-on-4 temp fracturing due to loosening of the angled abutment screw. Once the angled abutments are loose, it is a really big pain in the butt to seat them in the correct orientation!

Many of my colleagues running into complications with their big implant cases. Be fully aware that Fixed implant dentures, All-on4’s, implant bridges (whatever you want to call them) can and will break–especially the temporary set. 🎓Here are some tips to avoid the most common complications I am seeing: 💥Tighten the abutments all the way. Check their tightness every time the bar comes off. 💥 Eliminate occlusion at cantilever…or else 💥Minimize cantilever to reduce lever actions that will loosen or break your screws 💥 Establish level occlusal plane–even if this means delaying the implant case, this will give you a much better result. 💥 Make the framework passive. People often respond “Well technically it can’t be perfectly passive…” Go the extra mile and make it passive. #implantninja #allonfour #dentalimplant #implantología #implantology #implantesdentales #implantdentistry #dentalimplants #implantdentures #dentistry #dentist #oralsurgery #cirugiaoral #implante #implantes #prosthodontics #prosthodontist #dentist #fullmouthreconstruction #dentallab #lab #labtech #medical #art #prosthetics

A video posted by Ivan Chicchon DDS (@implant_ninja) on

Colleagues always ask me about how to manage this. Here are some of the ways that I have minimized this occurrence in my practice:

  • Occlusion! Make sure you have even occlusal contacts with group function. This means making sure they have a good opposing arch.
  • Ensure you are leaving enough acrylic thickness to withstand all the chewing ability you just gave back to your patient.
  • Make a vacuuform splint that the patient can use as a temporary night guard.

Insufficient Inter-Arch Space

This is a classic case of inappropriate planning. Implants were placed without reguard for how much inter-arch space was necessary and it led to the demise of the acrylic hybrid.



Do yourself a favor, before jumping into a placing implants, take a moment to make sure there is enough restorative space. I say 12mm for acrylic, 15mm for zirconia–PER ARCH. You can measure their existing denture, or you can actually do a full wax set-up (gasp!) when evaluating the case. This extra work spent planning will pay off considerably!

Inadequate Support at Cantilever

In this case, the cantilever fractured clean off:

_mg_1979 img_4750

Remember, you should always remove all occlusion at the posterior cantilever. In this case, you can see that the titanium bar did not extend distally past the last implant.  In addition, the bar appears polished and smooth–reducing any mechanical retention of the acrylic. These design flaws makes the cantilever of the prosthesis highly prone to fracture.

     Severe Angulation Prohibits Seating of Titanium Bar


Anyone who has placed an implant knows how it feels when after implants are inserted, you wish your angulation was a little different.  All-on-4 appointments are long and by the time the whole surgery is done and all those tiny abutments and screws are painstakingly put on, the last thing you want to see is a severely deviant angulation.

While, All-on-4 prosthetics are a little more forgiving in this regard–severely deviant angulations willl make it impossible for your framework to passively fit onto each abutment. Luckily some implant companies not only sell different angulations of abutments, but also different angled abutments with different rotational relationships to the implant.

Invest in learning to manage “Oh Crap” Moments

When I go to meetings, I am often surprised by how many people say they are ‘doing’ All-on-4 cases. My practice is completely limited to these types of larger implant rehabilitations so I am rather proficient  at this stuff by now– but I still run into issues sometimes.

My advice to someone who is looking to incorporate these treatments into their practice, is to look for a CE course that will teach you to manage complications of Full-Arch Implant Complications. This would be priceless. I don’t know of any that I can recommend, but you can bet that I will be developing one of these courses and begin offering it in 2017. (Update: We are now offering an online training course called All-on-Four “In a Box”. We teach how to make All-on-Four prosthetics and how to manage complications.)

This complications list is far from comprehensive. I’ll be posting some additional pictures and complications in Part 2 of this Article.

Subscribe to my blog to stay tuned for future articles and CE courses! 



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The Importance of Lip Support – Part I

Someone asked me the other day, “What is the most overlooked aspect of All-on-Four Dentures?”

By and large, I think the answer is lip support.

Too often, after hearing a patient say they want “permanent dentures” the case is hastily planned as an All-on-Four case. The implants are placed, the case is restored, and Viola!

But every so often, (especially if the case is not planned properly) a patient will end up with the appearance of a ‘sunken-in’ face and is not at all happy with the end result. Why?

I see many patients in this situation. They’ve already spent $50,000 at another clinic and are very unhappy with the results – so they come to me to see if I can fix it.

Just this upcoming week, I have a patient flying in from Arizona who had upper and lower All-on-Four done at one of those corporate implant centers. She was very unhappy because she want’s a fuller appearance, so she is flying to California to see me to have a new set of implant dentures made.

What This Article Will Teach You

Reading this article will help you understand to use lip ‘support’ as a diagnostic factor for implant dentures. After reading this, a little red flag should come up if you run into someone who is NOT a candidate for All-on-Four and I’ll explain some other possible options.

Sometimes the All-on-4 is the best treatment, other times it is not. Let’s run away from that cookie-cutter approach and instead, use a systematic examination for each patient.

So let’s dive in!

Lip support is the degree to which the tissues behind the lips provide backing (or support) so that the lips are properly ‘plumped’ and display esthetic facial contours. Fixed complete dentures (All-on-Four) can provide some support. However, in some cases, the patient is in need of more lip support than a fixed complete denture can provide.

In these instances, a removable prosthesis is recommended, instead. This is because a removable prosthesis can have a flange that extends into the sulcus that will plump-up the lip. 

Therefore, the amount of lip support required can determine whether the patient will be better treated by a fixed or removable prosthesis.

Bone Loss Over Time

If the absence of teeth, our jaw bones will shrink over time. As this bone loss progresses, the maxilla becomes narrower and shorter and the mandible becomes wider and shorter. (Pietrokovski et al 2007) Also, the crest of each alveolar ridge resorbs in such a way that the ridge appears to move posteriorly over time. 

This picture may serve to represent a patient who recently lost their teeth:


This picture shows the pattern of bone loss in both arches.


Bone resorption over time. The maxiilary ridge becomes narrower and shorter. The mandibular ridge becomes wider and shorter. Both resorb in a posterior fashion.

How to Classify Defects Caused by Bone Loss

A patient with a complete set of teeth has lip support provided by:

  1. the facial surface of the incisors
  2. the alveolar ridge.

Take a look at this next picture. The blue line in the figure represents the soft tissue facial profile:


If all the teeth were missing, some lip support is lost and lips would curl inwards. When a patient is missing only their teeth and not any significant amount of surrounding alveolar bone, the patient can be said to possess a “tooth-only” defect.

This figure represents a tooth-only defect:



As the alveolar bone remodels and resorbs over time, the patient will develop a composite defect. A composite defect is a clinical presentation in which a patient has lost some or all of the tissue volume previously occupied by their teeth, gums, and alveolar bone.

So, while in a tooth-only defect the patient has lost only their teeth, in a composite defect the patient has lost their teeth and some alveolar ridge volume.

A tooth-only defect usually progresses to a composite defect as the patient continues to lose tissue over their lifetime. A composite defect can become more severe over time especially in patients who utilize conventional dentures for many years.

A severe composite defect:



Let’s take a look at these concepts on an actual patient.

Let’s call this patient Mary. Mary has an upper conventional denture and a lower fixed complete denture on five implants (You could call it an All-on-Five).

Take a moment to evaluate her pictures and determine what type of defect you think she has: tooth-only, moderate composite, or advanced composite?

Here she is with her upper denture in place:


This is without her upper denture:


Now for a side view. Here is a pic with her upper denture:


And without her upper denture:



Mary is an excellent example of a severe composite defect. With her upper denture out of her mouth, her upper lip completely collapses and the edge of her lip curls inwards.

Even though she has a fixed complete denture in her lower jaw, it is possible to see evidence of her composite defect here too. Notice the very deep “mentolabial sulcus” (the horizontal fold seen right above her chin in side-view).

The prominence of this sulcus could be softened by the flange of a removable prosthesis. However, because she has a fixed prosthesis, she displays what is sometimes referred to as a “witch’s chin”.

Mary’s chief concern was that her “permanent denture” was driving her crazy. She explained that her lower lip felt like it was “too pushed out” and “the little crease at my lower lip bothers me.”

This is one example in which a removable implant overdenture may have been a better choice.

If a patient with a severe composite defect is treated with a fixed complete denture, a big problem will be the prominent sulci that can be formed and the sunken-in appearance that will result.

The same thing can be encountered in the upper lip in which a sulci, called the nasolabial fold, can be unintentionally created. This nasolabial fold can be seen in the following pictures.


For the following patient, I was able to actually eliminate the nasolabial fold just by rearranging the teeth on the existing metal bar.

IMG_4233 IMG_4236

The culprit behind it all can be seen in this next picture. If the patient has a severe composite defect, and they are treated with a fixed prosthesis, they will often end up with a “stair-step” between their prosthesis and their gums.


On the other hand, this following picture shows a beautiful prosthesis that adapts closely with the patient’s gums:


Ok, so we’ve covered a lot of ground here. Here’s a brief recap:

  • In the absence teeth, the maxiilary ridge becomes narrower and shorter. The mandibular ridge becomes wider and shorter. Both resorb in a posterior fashion.
  • Lip support comes from the facial surface of the incisors and the alveolar ridge.
  • When a patient is missing only their teeth and not any significant amount of surrounding alveolar bone, the patient can be said to possess a “tooth-only” defect.
  • In a composite defect the patient has lost their teeth and some alveolar ridge volume.
  • If a patient with a severe composite defect is treated with a fixed prosthesis, this may result in a nasolabial sulcus in the upper jaw or a mentolabial sulcus in the lower jaw.

Subscribe to the blog (upper left on desktop, below on smartphone) to stay tuned for Part II of this article in which we will go over the restorative options for these patients and how to trouble-shoot these cases.

I hope this article was informative. If you learned something, leave a comment and let me know 🙂


Dr. Ivan Chicchon

ps. check out my cases on instagram! @implantninja



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Item List for All-on-Four Denture Conversion

I’ve been getting this question a lot recently so I decided to make a quick reference list for you. Below are all the items you need for a All-on-Four Denture Conversion. I wrote the components as if the dental implants are Nobel Biocare Active because that’s what I use. (The picture above is from my friend and fellow prosthodontist @derekgatta)

(This list is for the All-on-4 denture conversion process only. This does not include components used in the surgical aspect of this procedure. )


  • The denture (can be old one or a newly fabricated one. Make sure to take a bite registration with the denture before the implants are placed.)


  • Fast-set Pink Acrylic (to reline the prosthesis for the pick-up procedure)
  • Blue Mousse (to mark the intaglio of the denture for adjustment and to stabilize the denture before the reline if necessary)
  • Wax, teflon tape, or fast set pvs (to cover the access holes during the pick-up)
  • Rubber Dam squares (to keep acrylic from running onto the patients gums)
  • Soft Reline Material (just in case you are not able to immediately load the prosthesis)


  • Acrylic Burs
  • Lathe & Pumice
  • Joe Dandy (to trim titanium cylinders)

Implant Components (you will not use every item on this list for 1 procedure but you will be well prepared for several surgical outcomes)

  • 2x RP 30 degree multiunit abutment conical connection
  • 2xRP 17 degree multiunit abutment conical connection
  • 3xRP temporary non-engaging titanium abutment
  • 4xRP temporary titanium abutment for multiunit abutment
  • 2x NP 30 degree multiunit abutment conical connection
  • 2xNP 17 degree multiunit abutment conical connection
  • 3xNP temporary non-engaging titanium abutment
  • 4xNP temporary titanium abutment for multiunit abutment
  • 1xNP straight multiunit abutment
  • 1xRP straight multiunit abutment
  • 4xMulti-unit impression copings
  • 2xNP conical connection impression copings
  • 2xRP conical connection impression copings
  • 4xmultiunit healing caps
  • 4xRP conical connection healing caps
  • 4xNP conical connection healing caps

In an upcoming article, I will explain the All on Four denture conversion process step-by-step . But for now, I hope this list is a valuable resource for you in obtaining your dental implant components for the big day!


Dr. Ivan Chicchon

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Will Mandibular Flex Ruin Your Implant Cases?

I recently posted a picture of a failed mandibular full arch zirconia prosthesis that got a lot of feedback, especially from lab technicians. The prosthesis was a mess, really. (It not done by me, thankfully). Some implants had screw retained attachments, some cement retained, many screws were fractured, and the zirconium bar was split right in half.

This is the prosthesis:

The thing that strikes me right off the bat is how thin the zirconium framework is. I have seen  several of these bars snap in half when they are not thick enough. (I’ve never seen a titanium framework do that.)

But the interesting thing for me was that I got a few comments stating that: 

“You cannot splint across the mandibular arch with posterior implants due to mandibular flexure.”

Is that true? Is it really contraindicated to do this? This is the topic I’d like to discuss in this short post. 

Mandibular Flexure DOES Occur

We all know mandibular flexure occurs–that fact is not contested. During opening and protrusive movements, the lateral pterygoid muscles cause the mandible to deform slightly. The amount of flexure is very small, but the thinner the mandible–the greater the amount of movement. Also, there is more flexure in the posterior region than the anterior region.

The practical implication of this is that if you are taking final impressions for a longer span prosthesis such as a bridge, a removable partial denture, or a fixed complete denture, then you should take the impression with the patient’s jaws relaxed and not open very wide in order to reduce the distortion. Also, for full arch implant prosthetics, you can improve the accuracy of your cast and passivity of your prosthesis by taking an extra step to verify your master-model. 

The role of mandibular flexure in splinted full-arch implant prosthetics is kind of treated like an urban legend. At a meeting, a speaker might mention to the audience: ‘I once had a patient once who had an inexplicable pain and we determined it must have been due to mandibular flexure.’ There are some case reports that speculate that mandibular flexure prosthetic complications, implant failures, and phantom pain. 

Let’s Look at a Couple of Articles…

Earlier articles claim that mandibular flexure is the cause of implant failure in the distal implants in these prosthetics. A study by Miyamoto et al (2003) compared a group of 7 patients with implants only in the anterior mandible to a group of 8 patients with implants in the anterior mandible and an additional implant placed bilaterally distal to the mental foramen. After 1 year, the implant survival rate was 100% and 60% respectively. They found that only those posteriorly placed implants failed in these patients and they claim that mandibular flexure was the reason. 

But in reality, we don’t have much data to make any definitive statements about this. One thing to consider about the Miyamoto article is that maybe the passivity of the framework was less ideal with the posterior implants. These metal frameworks were cast, so of course, a longer span of the framework will result in more distortion.

Also, this was before the age of CAD/CAM. Hardly anyone casts their frameworks anymore. Scanning and milling is used to create a more accurate framework than was possible almost 15 years ago when this article was published. Here is an example of me scanning my cast with the Nobel Procera Scanner:

An article published in the Journal of Prosthodontics in 2012 by Law et al, reviews the literature on this topic and concludes:

“The clinical significance of mandibular flexure on the success of dental implant treatment is at this time unclear, and further research is needed.”

Closing Remarks

So, is cross-arch splinting strictly contraindicated? Not necessarily. But flexure is something we should be keenly aware of when we are taking final impressions. Realize that flexure can have implications for the passivity of your framework so ALWAYS pay close attention to verifying your models.

Also, I’ll have a little more respect for the limitations. For instance, there is no reason to try to be a hero and place an implant as far back as a second molar site. Our choice is a balance between minimizing the cantilever and mitigating the effects of mandibular flexure. I will still aim for placing my implants around the second premolar site and then allowing myself a maximum of a 10 mm distal cantilever.

I would love to hear your thoughts. Do you have any experience with this? Have you seen any cases fail due to flexure?

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All-on-Three? How Many Implants Do You Place for a Full Arch Prosthesis?

How Many Implants for a Full-Arch Prosthesis?

There are staunch advocates for both sides of this debate. On one side of the extreme there are the minimalists who ask “What is the minimum number of implants that we can place?” The other side asks, “Why not place as many as possible just in case one fails?”

The Minimalists:


This picture is from a study by Rivaldo et al. 2012 at the Branemark institute in Brazil.  They placed 3 implants in the mandible and followed an immediate load protocol. At 1 year out, they had a 98%  survival rate: 98% and had a marginal bone loss similar to that of protocols including more implants.

If that is surprising, check this out:




This is from a Randomized Control Trial by Cannizzaro et al (2011). They compared the immediate load protocol of All-on-2 with the All-on-4.

At 1 yr out, they found…

    • implant survival rate: 100% for both
    • prosthesis survival rate: 100% for both
    • no statistically sig diff in post-op complications

This evidence notwithstanding, you’ll understand if I’m not ready to start doing this type of treatment just yet. Perhaps it may be best to wait for longer term studies….

The Over-Engineer-ists


On the other side are those who would rather “be safe than sorry.” I’ve heard any arguments for overengineering, including:

  • If one fails, there are more to fall back on
  • Natural gingival emergence is more esthetic than porcelain gums
  • Better hygiene access


And we all know that the All-on-Four technique has a significant amount of literature (and marketing) behind it. It cannot be argued that the technique doesn’t work.

Here’s some of the stats:

  • Studies by Malo et al:
    • (2015) 5 yr data
      • Prosthetic Survival 100%
      • Implant survival 95.5%.
      • More mechanical complications for both arches restored with All-on-4, than single arch.
    • (2011) 10 yr data (mandibular)
      • Prosthetic survival 99.2%
      • implant survival 94.8%.
  • Systematic Review by Heydecke et al (2012) w/ 4-6 implants
    • Maxillary
      • 5 yr prosthetic survival 97.5%
      • 10 yr prosthetic survival 95%
    • Mandibular
      • 5 yr prosthetic survival 97.9%
      • 10 yr prosthetic survival 95.9

Also, an engineering study conducted at Stanford University by Brunksi et al (2014) found that “with respect to axial loads on implants, there is no significant benefit to selecting 6 rather than 4 as long as the 4 implants span the same arc length as the 6.”


I have had some All-on-Four cases where the distal implant fails. In this situation, what can you do? Do you destroy your final prosthesis and jerry-rig a connection to a new implant?

Patient Factors

None of these philosophies is “absolute.” I don’t think that many of us would say we “always” place 4, 6, or 8 implants. The astute practitioner takes into considerations the many individual patient factors such as:

  • parafunctional habits
  • opposing dentition
  • alveolar ridge width
  • Anterior-Posterior spread attainable

Each approach has pros and cons. What is your philosophy? I encourage you to share your experiences or questions below.

Subscribe to the blog (upper left on desktop, below on smartphone) to stay tuned for upcoming posts and articles!

Like the post? Let me know by sharing, commenting, or rating the page. Thanks!


Ivan Chicchon


by the way…

You also got this type of “philosophy”…  Where do you stand?


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Zirconium Implant Dentures: Beautiful Outcomes and Catastrophic Failures


It’s always a good day when a delivery goes well. Just earlier this week I delivered an upper and lower porcelain veneered zirconium implant denture. The prosthesis sits on 4 implants in the upper arch and 4 implants in the lower.

implant denture Zirconium

The prosthesis seated perfectly and  the patient was shocked at how nice it looked. I always celebrate delivery days–and especially for bigger cases that exceed even my own expectations. This is a little video I posted on my Instagram of the delivery:


I celebrate because I know that for every success, there is bound to be a challenge. While I haven’t had this happen to my own work yet (knock on wood), I have been seeing many instances of fractured zirconia frameworks. 

Imagine as a patient, paying over $25,000 for a treatment and for it to end up with a catastrophic failure like bar fracture. Delivering big cases is a wonderful thing…but we must be prepared to deal with the complications!

In this case, the patient had 5 implants placed and restored with a zirconium bar. You’ll notice that 3 of the implants are screw retained and 2 are cement retained. The patient walked into the clinic with the prosthesis fractured down the middle and with 4 broken screws. several of the screws were not fully retrievable. Now, after spending all that money, the patient will be receiving a removable implant denture.

Here are some of the basics rules of thumb that I follow to avoid catastrophic failures:

  • Ensure PASSIVE fit of framework over all implants
  • Limit cantilevers as much as possible. I try to limit the cantilever to 10 mm, this is approximately one molar. When anatomical structures limit the positioning of the posterior implant, I place a tilted implant to gain a little bit of distal positioning and I recommend the Shortened Dental Arch concept.
  • Ensure sufficient restorative space (>12mm per arch and maybe more for zirconium). If there’s not enough space, the patient is likely to fracture it!
    • I like to use group function
    • Shallow cusps on molars
    • Make occlusal tables narrower B-L
    • Points of occlusion should be at center of the tooth and on a flat surface
  • Six month recall—FOREVER! At these appointments, I’ll be checking occlusion, cleaning the prosthesis (taking the prosthesis out if necessary and then placing brand new screws), and reinforcing oral hygiene instructions.
  • Occlusal night guard. I make these out of clear, hard acrylic.

There are some tricks but these are the most important points for keeping your implant dentures from self-destructing! I hope this helps!

Good Luck!
Ivan Chicchon

Click here for other cool Dental Implantology Pictures.

Check out my video on How to Make Implant Dentures Step-By-Step:
Part 1: Impressions
Part 2: Cast Verification
Part 3: Occlusal Records
Part 4: Coming up!