Overview of Dental Mini-Implants
Replacing missing teeth has been a concern since ancient times, and dentures used to be the primary solution. However, advances in science and technology have led to improved dental care solutions for most oral problems. Considerations for these solutions include restoring normal contour, function, appearance, comfort, speech, and overall oral health.
Now, a technique called osseointegration, which is the fusion of a dental implant with the jawbone, is the primary focus in modern implantology. This led to the development of various types of dental implants, ranging from 1.8 mm to 7 mm in diameter. A type of implant called a “mini implant” has been created that is smaller in diameter (less than 3 mm) and shorter compared to standard dental implants, but made from the same body-safe material.
Mini implants are primarily used to support overdentures, and because of their reduced size, they require less complex surgical techniques and can be placed in areas with thinner bone. This makes them a great option for many patients, as they are associated with immediate stability, high survival rates, favourable bone loss levels, less discomfort after surgery, and increased patient satisfaction and improved quality of life.
The number and type of implants (in terms of diameter and length) usually depend on the amount and quality of bone tissue available in the jaw. While overdentures supported by conventional implants have shown good long-term results, they also have limitations. These include higher costs, more difficulty in placing them in areas with reduced bone dimensions without needing additional bone-grafting procedures, and potential conflicts with chronic systemic diseases that can prevent more complicated surgeries like bone grafts.
At the same time, with mini implants, there is sometimes no need to make surgical incisions, which reduces complications during recovery. Other advantages include helping to expand the bone while being placed, needing minimal size for the bone opening, leading to better blood supply to the supporting bone, and easier healing process if removal is needed.
Patients who have used overdentures supported by mini implants reported excellent satisfaction in terms of comfort, retention, chewing and speaking ability, increasing their acceptance of mini-implant treatments.
Anatomy and Physiology of Dental Mini-Implants
Mini dental implants can be thought of as a smaller, one-piece version of conventional, or standard, dental implants. Regular implants typically consist of two parts: the implant, which is placed in the bone, and the abutment, which is connected to the implant and helps hold the replacement tooth. However, mini implants are made of a single piece of titanium, designed with either a ball-shaped or square head to help secure dentures or other dental prosthetics.
A mini implant can even have a head shaped like a bracket, which can be useful in orthodontic treatment to provide extra support or “anchorage”. Unlike conventional implants which are placed under the gums, mini implants sit slightly above the gum surface after being placed into the bone. The part of the mini implant that passes through the gums, called the “transmucosal portion”, needs to be smooth and its length depends on how thick the gum is at the implant site.
Why do People Need Dental Mini-Implants
Mini dental implants can be a good alternative for securing dentures when traditional larger implants can’t be used. They can be a great help for people who find normal dentures uncomfortable and who might have issues that make regular implants unsuitable. Mini implants can be used to fix bridges and replace one or more missing teeth, especially when the jawbone is thin. They also tend to be less expensive than regular implants, which can make them a good option for people who are budget-conscious.
Mini dental implants can be used when a person has lost all or some of their teeth and there’s not enough width in the bone for larger implants. They can be particularly helpful for teeth in the front upper jaw (the anterior maxilla), where the bone between the palate (roof of the mouth) and the lip might be too thin for traditional implants or there isn’t enough space between the teeth.
In the back of the lower jaw, an area known as the atrophic posterior mandible, a common reason for using mini implants is when the bone width from side to side (buccolingual width) is too small. Mini implants are also often used for braces. They help to apply the right force to move the teeth without causing unwanted side effects. Sometimes they can even be used instead of jaw surgery to adjust the position of teeth.
When a Person Should Avoid Dental Mini-Implants
Some people may not be a good fit for mini dental implant treatment due to various health conditions. Before proceeding with the implant process, it’s very important that doctors evaluate potential patients for any health risks or medical issues that could affect a surgery in the mouth and the healing process that follows. These could include, but are not limited to:
Heart and blood vessel conditions, not having control over one’s diabetes, problems with blood clotting, being on blood-thinning medication, habits like heavy smoking, bone diseases that affect metabolism, being on treatments like chemotherapy or radiation therapy. Inflammation of the gums that lasts a long time, not having enough soft tissue to cover an implant, or having some other metabolic or body-wide disorder that affects how wounds heal or how bones grow back could also be a concern.
People who may struggle to maintain good daily mouth cleaning habits, those who have uncontrolled habits like teeth grinding, those who don’t have enough height or width of their bone, or enough space between their upper and lower jaw bones, might also be unsuitable candidates for mini implants.
In situations where all the teeth are missing (a condition known as an edentulous arch), often at least two implants are needed because of the narrower implant size and uncertainty over the outcomes. There are also still things we don’t quite know yet about mini implants. Kids are not advised to get this treatment until they have fully grown, specifically when the development of long bones (an event termed as epiphyseal closure) is complete.
How is Dental Mini-Implants performed
Before having dental implant surgery, it’s crucial to gather as much information as possible about your oral health. This involves getting an overall view of your mouth and teeth, which can be done with a panoramic x-ray. For more detailed images, especially when the gums are very thin, a 3D scan known as a Cone Beam CT may be suggested.
Depending on the thickness of your gums, the surgeon might choose two methods. If your gums are wide enough, the surgeon can perform a ‘flapless’ surgery. This is where they make a hole for the implant directly through the gums. However, if your gums are very thin or you have a lot of soft tissue, the surgeon might ‘raise a flap’, or make a small cut in the gum to reveal the bone underneath. This helps to place the implant more accurately.
The mini dental implant system used in the surgery is designed to cause minimal discomfort. It’s important the implant remains stable after placement for successful bone growth around it, known as osteointegration. This stability relies on the quality of your bone, the design of the implant, and the surgical technique used.
The strength of dental implants in the top jaw (maxillary implants) can sometimes be compromised by the angle they are placed, the thickness of the gum tissue, or small movements due to the implant not aligning well. To keep the implant-supported false teeth (overdenture) secure, the rings connecting them to the implants may need to be changed from time to time.
During the implantation surgery, a torque of 35 N/cm is applied using a ratchet tool to secure the mini dental implants in place. After surgery, adjustments and maintenance are needed over time. To ensure even distribution of chewing forces and prevent damage to the implants and surrounding bone, it’s important to adjust the alignment of your false teeth and implant, as well as routinely refresh the lining of the false teeth set.
In the installation process, the surgeon marks areas around your lower jaw (specifically around the mental foramen, which is an opening in the lower jaw bone that nerves pass through). It ensures a safe placement of the furthest back implant, factoring in any anatomical features and providing a safe margin.
Possible Complications of Dental Mini-Implants
There are a few potential drawbacks to consider when getting mini implants for dental treatment:
1. You might need more than one implant. This is because there’s still a lot of uncertainty about how best to use these implants, and there are no clear guidelines yet.
2. There’s limited information about how long these implants can last.
3. There’s a risk that the implant could break during placement, the screw could become loose, or there could be problems with the prosthetic teeth.
4. The implants have to be aligned perfectly, which can be difficult because they’re designed in one piece.
5. These implants may not be as strong when you’re chewing, so the dentist has to check how the fake teeth spread out the forces when they bite down.
There are also some risks when the surgery is done without making a big cut (flapless). For example, the dentist won’t be able to see the bone, clean it with a fluid, or reshape the bone to get more space for the implants.
After the surgery, there can be complications like inflammation and progressive bone loss around the implant, infection at the implant’s tip, or numbness. The implant might not be fit tight if the bone’s outer layer is thinner than 0.5 mm or the inner part of the bone is not dense. There can be an infection if the part of the implant that goes through the gum is not smooth. Also, if the implant is inserted with too much pressure, the tip may break.
If the screw is tightened too much, it can become loose. You should stop tightening when the smooth part of the screw reaches the outer layer of the bone. Also, when using the implant as an anchor for braces, trying to thread a wire around the screw could cause inflammation. Instead, the wire should be placed in a slot atop the screw.
What Else Should I Know About Dental Mini-Implants?
Despite some drawbacks, mini dental implants (small artificial teeth roots) are growing in popularity, especially for people without teeth. Here’s why:
1. More people need full sets of dentures (artificial teeth).
2. Regular implants are becoming more expensive.
3. People with financial limitations or those who need facial prosthetics can more easily access mini implants.
4. Patients with certain health conditions may not be able to undergo traditional surgeries or procedures to build up the area where the implant would be placed.
5. Mini implants can be used as temporary supports for the false teeth during the healing process after implant surgery.
6. In cases when there’s not enough space or bone for a standard implant, a mini implant can support a permanent single tooth.
There’s been growing interest in implant dentistry among general dentists. Therefore, it’s important to look at current research and clinical data on mini implants’ long-term performance for definitive dental prosthetic treatment i.e. replacing missing or lost teeth with artificial ones.
Several factors influence how successful mini implants are:
1. The design: Improving the shape, thread patterns, and surface treatments of mini implants can enhance their initial stability and speed up the process where the bone fuses with the implant (osseointegration).
2. The size: The size of the mini implant affects how much retention it can have in the bone.
3. Occlusion and masticatory forces: A good bite and chewing forces significantly influence the success rate of mini implants.
4. The number and position: How many mini implants are used and where they are placed within the false teeth can affect the forces acting on the bone surrounding the implants.
5. Stress distribution: Factors such as the diameter and shape of the implant and the direction of the load influence how stress is distributed.