The purpose of this research study is to identify reasons that cause an all-ceramic bridge to fracture which include the thickness of the bridge material, the type of bridge material and the bite force of the person. This all-ceramic bridge will be compared to a metal-ceramic bridge. The investigators are conducting this study so we can make bridges which can withstand forces in the mouth which tend to break them.

The overall objective of this research is to analyze how properties of ceramic materials and different forces in the mouth interact with each other to affect the longevity of these bridges. These include fracture toughness, elastic modulus of ceramic layers and supporting substrate, core thickness, connector height, wear, loading orientation, and maximum clenching force.

The long-range goal of the proposed research is to formulate design survival statistics that will aid the dental community in fabricating properly designed prostheses that can predictably survive the oral environment.

Patients who qualify for this study will be randomized (as in chanced with the flip of a coin) into two groups. The first group is a metal-ceramic group where patients will receive a bridge with a metal substructure underneath. The second group is an all-ceramic group where patients will receive a bridge which is made of hard ceramic material. All patients will receive two dental implants which will bond to bone for a period of 4-6 months. An impression or mold of the implants will then be made and a bridge will be fabricated based on the randomization of the patient. Patients will be asked to return at 6 months and yearly thereafter up to 5 years. During these recall appointments, photographs will be taken and impressions of the bridge and other teeth will be made. This will allow us to measure the amount of wear happening with the bridge and the other teeth. The investigators can also examine the amount of bone around the implants as well as the integrity of the bridge.

Inclusion Criteria:

• Aged between 21-75 years, and no contraindications to dental treatment.
• Good overall dental health, no active caries, no periodontal disease, and periodontal pocket depths not greater than 4 mm.
• Missing at least three teeth in the posterior area of the mouth.
• Natural teeth opposing the edentulous area and a full complement of teeth or restored teeth in all other areas of the mouth
• Adequate bone height and width at areas of proposed implant sites
• Adequate interocclusal distance to accommodate prosthesis
• Good oral hygiene and compliance with oral hygiene instructions as determined by the amount of plaque present on tooth surfaces.
• Compliance with appointments and willing to pay $2625 for a 3-unit implant supported FDP

Exclusion Criteria:

Non compliance Not enough teeth remaining Uncontrolled medical condition

Patients accessing a dental clinic for bridge placement