What is the All-on-4 treatment?
All-on-4 is a term used to describe the replacement of a complete set of teeth in either the upper or lower jaw, supported by 4 dental implants.
What are the prosthetic teeth made of?
After the dental implants have healed into the bone, a permanent set of teeth will be fabricated and inserted into the dental implants. In the majority of cases, the composition of the teeth includes a metal bar substructure with plastic teeth and pink acrylic resin wrapped around the bar. The teeth are held in position by the pink acrylic and metal bar. The teeth are then screwed into the implants and fixed in place. Only an experienced dentist or prosthodontist can then remove the teeth.
Are there any potential problems with the teeth?
Plastic teeth and acrylic were originally created for making removable dentures. Denture acrylic is porous and therefore easily collects stain and plaque if the material is not properly cleaned. It is necessary to remove dentures from the mouth to properly disinfect and clean. If plastic teeth and acrylic are wrapped around a metal bar, which is permanently anchored to dental implants, a patient is not able to thoroughly clean the prosthesis. Stain and plaque accumulates creating bad breath and poor oral hygiene (See picture above).
A significant problem is that there is a risk of breakage when plastic teeth and acrylic resin are used for full-arch implant bridges in the upper jaw. In a recent study from August 2013 in the journal of Clinical Implant Dentistry and Related Research, investigators found that the use of plastic teeth and acrylic can lead to a need for frequent maintenance repairs of five or six times per implant bridge during a 10-year period. This means that after spending thousands of dollars for a a fixed set of teeth, the plastic teeth can break off of the metal bar multiple times during a 10-year period. From my experience, the front teeth most commonly break and this can occur within the first year of functioning with the bridge (See picture above). This can be extremely frustrating for the patient because this complication requires immediate repair to avoid the embarrassment of a lost tooth. Tooth breakage is unpredictable and can happen anytime. Patients need to understand this consequence before starting treatment.
Can the implant bridge be fabricated from a different material?
Yes! No dental material is perfect and each design has positive and negative aspects. Implant bridges can also be made with porcelain fused to metal or zirconia. Bridges made with these materials are easier for the patient to maintain. These materials are smooth, highly esthetic and easier to clean in the mouth. In addition, these materials are solid with less chance that teeth will completely fracture from the substructure as reported with denture teeth. Possible complications include chipping of the porcelain from the metal or zirconia. If the implant bridge is designed carefully by a prosthodontist, these complications can be minimized.