Medical uses and increasing use of dental implants
– Dental implants are used to replace missing teeth, support dental prosthetics, decrease movement in a lower denture, and support a bridge of teeth.
– The integration of implant and bone can support physical loads for decades.
– In the US, the usage of dental implants has been increasing, with 5.7% of patients missing at least one tooth in 2015-2016 and a projected potential reach of 26% in 2026.
– Dental implants can also be used in orthodontics and facial prosthetics.
Different types of dental implant restorations
– Single tooth implant restorations are used to replace missing individual teeth, with an implant abutment secured to the implant and a crown connected to the abutment.
– Implant-supported fixed bridges are a group of teeth secured to dental implants, with the prosthesis supported and retained by one or more implants.
– Implant-supported overdentures replace teeth using implants, providing improved support, retention, and stability compared to traditional dentures.
– Implant-supported bridges can replace as few as two teeth or an entire arch.
Orthodontic mini-implants and small diameter implants
– Orthodontic mini-implants, also known as temporary anchorage devices (TAD), provide additional anchorage points for orthodontic movement.
– Small diameter implants, or mini implants, provide immediate functioning transitional prostheses and are suitable for patients with inadequate bone structure.
Composition, technique, and biomechanical considerations of dental implants
– Dental implants are made of titanium, with commercially pure titanium (CP4) commonly used for implants and grade 5 titanium (Titanium 6AL-4V) used for abutment screws and abutments.
– Implants can also be made of ceramic (zirconia-based).
– Planning techniques involve creating guides and simulations, using plaster models, and loading CT scans to CAD/CAM software for treatment simulation.
– Biomechanical considerations include ensuring implants support forces evenly to prevent fractures or loss of bone, considering the location of implants based on biologic and mechanical factors, and using CT scanning to identify vital structures and plan surgery accurately.
Risk of BRONJ, main surgical procedures, timing of implants after tooth extraction, and one versus two-stage surgery
– The risk of bisphosphonate-related osteonecrosis of the jaw (BRONJ) from dental implant placement is low, but higher with intravenous therapy, procedures on the lower jaw, and certain medical conditions.
– The main surgical procedure for dental implants involves making an incision, reflecting the flap of tissue, creating an osteotomy, placing the implant fixture, attaching a healing abutment, and suturing the gingiva.
– Timing of implants after tooth extraction can be immediate, delayed immediate (two weeks to three months after extraction), or late (three months or more after extraction).
– One-stage and two-stage surgeries have similar implant survival rates, with the choice depending on soft tissue management and the condition of the tissue.
– Internal components of dental implants include healing abutments and cover screws, and soft tissue management is a concern in the choice between one-stage and two-stage surgeries.
A dental implant (also known as an endosseous implant or fixture) is a prosthesis that interfaces with the bone of the jaw or skull to support a dental prosthesis such as a crown, bridge, denture, or facial prosthesis or to act as an orthodontic anchor. The basis for modern dental implants is a biological process called osseointegration, in which materials such as titanium or zirconia form an intimate bond to the bone. The implant fixture is first placed so that it is likely to osseointegrate, then a dental prosthetic is added. A variable amount of healing time is required for osseointegration before either the dental prosthetic (a tooth, bridge, or denture) is attached to the implant or an abutment is placed which will hold a dental prosthetic/crown.
Success or failure of implants depends primarily on the thickness and health of the bone and gingival tissues that surround the implant, but also on the health of the person receiving the treatment and drugs which affect the chances of osseointegration. The amount of stress that will be put on the implant and fixture during normal function is also evaluated. Planning the position and number of implants is key to the long-term health of the prosthetic since biomechanical forces created during chewing can be significant. The position of implants is determined by the position and angle of adjacent teeth, by lab simulations or by using computed tomography with CAD/CAM simulations and surgical guides called stents. The prerequisites for long-term success of osseointegrated dental implants are healthy bone and gingiva. Since both can atrophy after tooth extraction, pre-prosthetic procedures such as sinus lifts or gingival grafts are sometimes required to recreate ideal bone and gingiva.
The final prosthetic can be either fixed, where a person cannot remove the denture or teeth from their mouth, or removable, where they can remove the prosthetic. In each case an abutment is attached to the implant fixture. Where the prosthetic is fixed, the crown, bridge or denture is fixed to the abutment either with lag screws or with dental cement. Where the prosthetic is removable, a corresponding adapter is placed in the prosthetic so that the two pieces can be secured together.
The risks and complications related to implant therapy divide into those that occur during surgery (such as excessive bleeding or nerve injury, inadequate primary stability), those that occur in the first six months (such as infection and failure to osseointegrate) and those that occur long-term (such as peri-implantitis and mechanical failures). In the presence of healthy tissues, a well-integrated implant with appropriate biomechanical loads can have 5-year plus survival rates from 93 to 98 percent and 10 to 15 year lifespans for the prosthetic teeth. Long-term studies show a 16- to 20-year success (implants surviving without complications or revisions) between 52% and 76%, with complications occurring up to 48% of the time. Artificial intelligence is relevant as the basis for clinical decision support systems at the present time. Intelligent systems are used as an aid in determining the success rate of implants.