Zygomatic Versus Conventional Dental Implants in Augmented Maxillae

Zygomatic Versus Conventional Dental Implants in Augmented Maxillae: a Pragmatic Multicentre Randomised Clinical Trial.

Dental implants are used for replacing missing teeth. Placing dental implants is limited by the presence of adequate bone volume permitting their anchorage. In order to solve this problem several bone augmentation procedures have been developed. In principle the missing bone is taken from a donor site (for example the hip), transplanted where needed and then implants are placed. Sometimes, major bone grafting operations have to be undertaken under general anaesthesia requiring patients to be hospitalised for a few days. Some degree of morbidity related to the donor site must be expected, though more recently bone substitutes are used to minimize morbidity, and 2 to 3 surgical interventions may be needed before the implants can be functionally used. Sometimes patients have to wait more than 1 year before a prosthesis can be fixed to the implants and the total cost of the treatment is high. At the beginning of the 1990s a long screwshaped implant was developed by Professor PI Brånemark as an alternative to bone augmentation procedures: the zygomatic implant. Zygomatic implants are generally inserted through the palate to engage the body of the cheek bone. One to three zygomatic implants can be inserted through the posterior palate to engage the body of each cheek bone. The potential main advantages of zygomatic implants could be that bone grafting may not be needed and a fixed prosthesis could be fitted the same day of their placement. Despite that zygomatic implants have been used for more than 20 years, their effectiveness has never been compared with conventional dental implants in augmented maxillae. The aim of the project is to compare the longtermclinical outcome of fullarch upper jaw bridges supported by zygomatic implants versus conventional implants placed in augmented bone in the palate.

Inclusion Criteria:

• fully edentulous patients
• atrophic maxilla
• insufficient bone volume for placement of dental implants
• patients with no more than 4mm of bone height sub-antrally

Exclusion Criteria:

• general contraindications to implant surgery
• history of radiation therapy
• immunosuppressed/immunocompromised patients
• patients taking bisphosphonates
• poor oral hygiene
• patients with untreated periodontitis
• uncontrolled diabetes
• pregnancy
• alcohol/drug addiction
• lack of opposite occluding dentition/prosthesis
• restricted mouth opening.