The Benefits of Mini Dental Implants

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From Dentaltown.com
By Eric Hanson, DDS

As dentists, almost all of us have encountered the patient who comes to our practice to get a new denture because the old one "just doesn't fit." This usually requires a few more questions to get an accurate idea of exactly what the patient means, but what it usually boils down to is this: the lower denture floats around when eating, gets food under it, creates sore spots, and is generally a nuisance.

Upper dentures rarely, in our experience, have these same issues. Lower dentures almost universally do. What do you do when this patient comes in your door? Making a new denture may or may not improve things, and a careful evaluation of the existing denture and the patient's oral condition is warranted as the first step in deciding on a solution.

During this evaluation, you may discover that the patient has worn a denture successfully in the past and has recently lost weight and now says it is "loose." Or you may find out the denture was originally an immediate denture that had never been relined and now, after months or years of osseous resorption, the denture is indeed very loose. In these cases, a new denture alone may improve things. Otherwise, simply making a new denture will result in frustration on your part and the patient's. It is important to take the time to recognize whether making that new denture is the only procedure needed to solve the patient's problem.

One thing is universal, however, and that is this: Securing the denture with dental implants will change your patient's life for the better, and whether or not you currently provide this service in your practice, letting the patient know it is an option is part of your obligation as his or her dentist. There are few procedures we offer that are truly life-changing, but helping a patient return from the land of the dental cripple is one of them.

Providing a service to denture-wearing patients that will eliminate the majority of their problems and allow them to return to a normal diet is a blessing most of them want—especially if it can be done at an affordable fee.

Denture retention options
The dental cripple (as we will refer to this patient) has many options. One option is to do nothing, of course. There are millions, perhaps many hundreds of millions of people worldwide who have few or no teeth and manage to ingest enough calories to survive. Teeth are not necessary for survival. However, in North America, the vast majority of people not only want to survive, but they also want to eat what they consider to be a normal diet and to look good doing it.

The second option is denture adhesive, a multi- billion-dollar industry. Most denture wearers will also tell you they would like to live without the mess and inconvenience of powder or paste and without the embarrassing possibility of coughing out a denture at a family party.

Dental implants are the third option listed here, but really should be the first option presented to patients because almost every edentulous patient can have his or her life improved with them.

Implants can be used to support or retain a denture, or to replace it. Denture replacement is an important option that involves several dental implants per arch and a fixed prosthesis to be fabricated. This should be presented to patients when biological limits allow. Denture replacement is beyond the scope of this article, but several overdenture systems are available that will be outlined below. The advantages and disadvantages of each will be presented, based on our personal observations.

The implant bar-supported denture
Implant bar-supported dentures have been in existence for several decades and have enjoyed a great deal of success. Dental implants are placed and allowed to integrate, then a bar is manufactured by a dental lab, and the denture fabricated afterward. Bars can be made with several attachment types, including the Hader Clip system, Locator-type attachments, and O-ball attachments. The bar can, in many cases, allow the denture to be fully supported, not just retained. Each has its own peculiarities and we won't try to cover all of them in this article.

Advantages
Denture is off the tissue so it can cause no irritation
Denture is usually completely supported
Denture is very stable
Patient chewing ability is very good
Can often be "upgraded" to a fixed prosthesis without additional implant placement
High patient satisfaction
Disadvantages
Expense
Cleanability
Complicated, multistep process to make or remake prosthesis
Technique-sensitive lab procedure
Technique-sensitive chairside procedure if attempting to reline denture or "pick-up" denture attachments
Bone height must be low enough to accommodate implants, bar, attachments, and denture material
Bone must be at least 7mm wide for a 3mm diameter implant

Four-Locator or Four O-ball system
Rather than placing two implants in the canine areas only, two more are placed distally, provided there is enough bone width to accommodate them. A variation on this is a three- implant system where one is placed at, or close to, the midline with two others in the posterior areas.

Advantages

  • Excellent denture retention
  • Cleanability
  • Upper denture can have palate removed
  • Little to no rocking or other movement of the prosthesis
  • Easier lab and chairside procedure than bar system
  • Can be upgraded to a fixed prosthesis, possibly without additional implant placement
  • High patient satisfaction
  • Replacing liners or O-rings is fairly fast and easy
  • Disadvantages
  • Patient expense
  • Sinus lift or mandibular bone grafting may be necessary for adequate bone height
  • Large O-balls require shorter bone to accommodate the O-ball and housing
  • Bone grafting may be necessary to accommodate 3mm-plus diameter implants



Mini dental implants
Mini dental implants, those described as being <3mm diameter, are used for overdenture retention. Four to six implants are usually placed and "loaded" six to 12 weeks later. Some practitioners load immediately when minimal torque requirements are met. Our experience is that a six-week waiting period results in a significantly higher success rate than immediate loading. Locators or O-ball systems exist, with the smallest diameter implants being O-ball type.

Advantages
Excellent denture retention when at least four are used
Cleanability
Lowest patient expense (when one-piece O-ball implants are used)
Can accommodate the most extensive variation in bone height and width
Bone grafting is almost never needed
Sinus lift procedures almost never needed
Low-trauma surgical procedure is simplest, requiring about an hour per arch.
Surgical armamentarium requirement is smallest
Chairside and lab prosthetic procedure is simple
Easiest procedure to replace a failed implant (if necessary)
Shorter healing (integration) period
Palate of upper denture may be removed in most cases
Lowest chair-time requirement
High patient satisfaction
Can be used for claspless partials in many cases
Replacing O-rings (on O-balls) is fast and easy
Fantastic opportunity to obtain experience in implant dentistry


Disadvantages
Individual implant failure rate may be higher than for root-form implants
Unchangeable abutment type, not as versatile for "upgrade" later
Lower denture will rock somewhat if resorbed posterior mandible is present
Periodontists and oral surgeons generally don't care for them, believing root-form implants to be superior, and mini implants being merely for use as Temporary Anchoring Devices in orthodontics

Discussion
We have performed all of the above procedures in our practice. We have also restored implants placed by other practitioners. To us, mini dental implants are the most sensible option for almost all patients when considering an overdenture. They require the least amount of trauma, which is advantageous for the fearful patient, and the least expensive, which gives the procedure wide appeal to the average Joe.

As far as we can tell, patient satisfaction with them is highest, especially when taking into consideration the fact that most of the time, a denture is more esthetically pleasing than a fixed bridge. Patients, even those with a badly resorbed mandible, are able to chew well and eat most foods with a bit of practice.

We have also observed that once the attachments are placed in the denture and the prosthesis adjusted, we rarely hear from our overdenture patients who have had minis placed. Mini implant retained overdentures appear to be the most problem-free system we have seen or personally used.

One question that frequently comes up is longevity. The first patient for whom I placed minis more than seven years ago had a severely resorbed mandible with no attached gingiva. Ten-

millimeter mini implants were placed. She did not come in to see us for five years and, as a result of poor oral hygiene, had some inflammation of the mucosa around the implants. I offered to remove the implants to relieve it and also offered to have her see the periodontist for soft tissue grafting. The patient refused both options and the hygienist has been providing implant maintenance every three months, with some improvement in the inflammation. The patient is in very poor health with an undiagnosed wasting disease. The point is, in spite of the imperfect situation, the patient doesn't want to return to life before minis!

Another example: a patient came in about a year ago with four mini implants in the mandible, placed by another practitioner. They were clean, in great shape, and had zero bone loss.

All I did was make a new overdenture, because the patient had paid the highest compliment a denture wearer could pay to the dentist who provided it: by chewing so many meals that the overdenture was worn out! Those implants had been in use for more than 11 years at the time. So much of the longevity of any implant is dependent on factors beyond the practitioner's control, the most important of which is the patient's oral hygiene.

In our practice, we have found Lew mini dental implants—manufactured by Park Dental Research—effective and reliable. The company's philosophy of producing implants at an extremely affordable price meshes very nicely with our practice mission of providing high-quality dental care at affordable fees. But whatever mini dental implant you choose, we believe that this method will help you effectively treat—and forever change the life of—the dental cripple.

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