Last time, we discussed the process of restoring multiple missing teeth with a denture or a partial denture. Dentures and partials serve a great purpose, but the biggest concern patients have with them is the fact that they are removable prostheses. Often times people are looking for a treatment option that is more fixed in place. Thanks to dental implants, this kind of treatment is possible. Dental implants can be used in multiple ways to provide more retention for dental devices.
How Does an Implant Work?
A dental implant is a titanium screw-like structure that is surgically placed below the gums into the jaw bone. This gives stability for a dental prosthesis to be anchored to.
Single Dental Implant
Dental implants take a lot of planning. Often times a surgeon will need two or three dimensional imaging to check on the anatomy of the desired implant site. Implant placement is dependent on the integrity of the bone that it is being placed into. If there is not enough bone available to support an implant then surgeons have to do a little more to prepare the site, which may include bone grafting or sinus elevation. While the implant has to be placed in a site that has appropriate bone, the surgeon also has to be aware of the proper placement and angulation so that the restorative dentist is able to place a suitable restoration on the implant.
In terms of treatment timeline every implant case is different. In the most straightforward single implant case, an implant is surgically placed and then will take time to heal and integrate into the bone for 3 to 6 months. Once the surgeon confirms that the implant is stable and ready for its crown the restorative dentist will take a scan or impression so the lab can make the implant crown. After a few weeks at the lab the permanent implant crown will be ready to be placed on the implant. This treatment timeline may be extended by different factors that may require more healing time such as tooth extractions, bone grafting, sinus elevation, or ridge augmentation.
While the implant integrates into the bone it is important that it is free of any force that may disrupt the healing process. Often times implants will be placed into the bone and sealed with a healing cap which sits at the gum level and keeps the implant protected and out of the way of chewing forces. If the missing tooth is close to the front and a patient wants something in the missing tooth space for esthetic purposes then a separate essix retainer or flipper can be made. These are removable temporary devices that seat around the teeth with a replacement tooth in the open space.
Essix Retainer
Flipper
In some occasions a temporary implant crown can be placed on the implant at the time of surgery, but it is important that the surgeon has enough initial stability of the implant during surgery to do this. The temporaries also need to be adjusted to stay out of the force of the bite and it’s important that the patient avoid the temporary when eating and stick to a softer diet so that the integration of the implant is not disrupted by any forces. Ultimately, the implant having the appropriate environment to heal and integrate properly is the most important factor, so the temporary options for esthetic purposes is very case dependent.
Implant Supported Bridges
Sometimes more than one tooth needs to be replaced; this could be a span of a few teeth, or an entire arch of teeth. An implant supported bridge is a restorative option that can use two implants to cover a longer area of missing teeth. Each end of the bridge is anchored by an implant and the middle is connected with ‘pontic’ teeth that span the area sitting over top of the gums. If just a few teeth are missing on one side of the mouth then sometimes an implant supported bridge can be used to restore that whole area. If a larger area is missing teeth then multiple segmented bridges can sometimes be used to restore all of the missing teeth in pieces.
Implant Bridge
As with all implants, an implant supported bridge will require adequate bone availability and may require additional treatment and planning if this is not the case. Dependent on location and stability of the implant bridge, sometimes a temporary bridge can be placed on the implants the same day as the surgery. However, due to the implants needing to be able to appropriately heal without outside forces, more often a patient will wear a removable temporary device such as an essix retainer, flipper, or denture while the implants integrate and wait to be restored.
The benefit of an implant supported bridge is that it is an option that is fixed in place but does not require an implant be placed in each site that is missing a tooth. However, since the restoration is all attached, if any issues arise with one of the implants it can compromise the integrity of the entire bridge. This is why it is very important to keep clean under the bridge and around the implants so that they stay in good health. A water pick is an excellent tool to keep clean around implants and implant bridges.
Overdenture
An implant supported overdenture is a dental prosthesis that replaces an entire arch of missing teeth. It sits over the gums in a similar way that a conventional denture does, but it also uses implants for additional retention. Implants are placed and their abutments sit just above the gum level. There are corresponding components built into the denture that match up to the implant abutments that allow the denture to ‘snap’ into place. The implants keep the denture engaged and significantly increase the retention.
Overdenture
Overdenture- internal components
In overdenture cases, typically patients will have a time period where they are in a conventional denture throughout the preparation and healing period. This allows the patient to have a replacement option while the bone heals and remodels following extractions and also gives time for the implants to be placed and given adequate time to integrate into the bone. Once everything is healed and the implants are stable the existing denture can be converted into an overdenture that works with the implants, or a new denture can be made to the existing implants.
Implant supported overdentures are especially popular options for the lower arch. This is because often times patients find success with a traditional upper denture because it suctions well to the palate. In contrast, a traditional lower denture often times gives patients a little more frustration. This is because due to the location of the tongue and less surface area to cover it tends to move a lot more. Even just two implants for a lower overdenture can greatly increase the retention and patient satisfaction.
Overdentures are great treatment options because they replace an entire arch of teeth with one prosthesis. They also cover over the gum tissue so if there are any discrepancies in the architecture of the gums it will esthetically replace that as well. Another great feature is the ability to keep clean. The implants provide excellent retention for the prosthesis, but it is still something that is removable. This is nice because it allows the patient to remove the overdenture to clean both the prosthesis and around the implants along with giving the tissues a break.
Hybrid Denture
A hybrid denture is a dental prosthesis that replaces an entire arch of teeth with one prosthesis fixed to implants. Sometimes these are referred to an all-on-four or all-on-six depending on how many implants are fixing it in place. Some of its features that make it similar to a denture are that it replaces an entire arch of missing teeth and that it replaces some aspects of the gum tissue. What makes it different than traditional dentures or an overdenture is that it is something that is completely anchored in place and cannot be taken in and out by the patient.
Hybrid Denture
Hybrid Denture
When planning for a hybrid denture, records are taken in advance to help determine the appropriate dimensions of the future prosthesis and the desired location of the implants. Teeth are extracted and bone is removed to make sufficient room for the entire hybrid denture. It’s important that there is plenty of thickness to the hybrid so that it is strong in supporting the force of the bite.
During the surgical appointment teeth are removed, the bone is re-contoured, and the implants are placed in their planned locations. Often times a complete denture is already made for the patient so that they have something to replace their teeth for the time being. If the surgeon is able to get enough initial stability with the implants on the day of surgery then they can work with the already made prosthesis and connect them to the implants as a temporary device. It is important that if the device is connected to the implants that the occlusion is designed in a way that balances any forces so that the implants don’t experience any stress during the time they are integrating. It is also crucial that the patient stick to a completely soft diet during this healing time with the temporary.
Once the implants have fully integrated the permanent device is made. This device will screw into the implants and be completely fixed in place. Hybrids dentures are becoming increasingly popular as a full arch treatment option because patients enjoy that there is no movement to the prosthesis; however there are still things to consider. Since this full arch prosthesis is fixed in place it is not as cleansable as a denture or overdenture. It is very important that the patient works to keep things clean at home. This often times will include getting a water pick to clean underneath the hybrid and around the implants. Also, about once a year the patient should see their dentist for professional removal and cleaning of the hybrid to make sure the implants stay healthy.
Dental implants are a service that gives patients more retentive treatment options for replacing teeth. The dental team will work to provide different treatment plans that are appropriate for a patient from both a functional and esthetic stand point. There are many things a patient needs to consider when deciding on treatment: amount of surgery they are comfortable with, how much retention they are looking for in a dental device and if they desire a fixed or removable option, treatment timeline, esthetics, and finances. These aspects of treatment all carry different weight to people and is something that a dental team can discuss in detail with patients to help finalize a full treatment plan.