Zygomatic Versus Conventional Dental Implants in Augmented Maxillae

Study Overview
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Brief Summary
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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.

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

Conditions
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Edentulous Maxilla, Resorbed Maxilla, Implant Therapy

Intervention / Treatment
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* Device: Zygomatic implant placement
* Device: conventional implants and augmentation of maxilla


Participation Criteria
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Eligibility Criteria
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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.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Zygomatic Implants<br>2-4 zygomatic implants inserted into edentulous maxilla with no augmentation/grafting prior to providing patient with dental prosthesis | Device: Zygomatic implant placement<br> <br> |
| Active Comparator: Bone Graft and Conventional implants<br>Edentulous maxilla which is deficient in bone is first grafted using bone grafting material derived from cows and then ordinary implants are placed into the augmented jaw bone approximately 6 monhts after grafting. Patients will be provided with a dental prosthesis following osseointegration. | Device: conventional implants and augmentation of maxilla<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Implant success | Implant failure is defined by implant mobility +/- infection dictating implant removal. | 1 year following implant loading | 
| Implant success | Implant failure is defined by implant mobility +/- infection dictating implant removal | 3 years following implant loading | 
| Implant success | Implant failure is defined by implant mobility +/- infection dictating implant removal. | 5 years after implant loading | 
| Implant Success | Implant failure is defined by implant mobility +/- infection dictating implant removal | 7 years after implant loading | 
| Implant Success | Implant failure is defined by implant mobility +/- infection dictating implant removal | 10 years after implant loading | 
| Implant success | Implant failure is defined by implant mobility +/- infection dictating implant removal | 15 years after implant loading | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Complications | Biologic and prosthetic complications will be assessed. Biologic complications include perimplantitis, maxillary sinusitis,abscess, fistula, gingival dehiscence. Prosthetic complication: abutment fracture | 1 year | 
| Change in marginal bone levels on intra oral radiographs | To be evaluated on intraoral radiographs taken with the paralleling technique at implant placement, at delivery of the provisional prostheses, 1, 3, 5, 7, 10 and 15 years after loading. | 1,3,5,7,10,15 years | 
| Failure of augmentation procedure | The augmentation procedure will be considered a failure if, after it has been performed, it will not be possible to place the planned implants in the augmented site. | 6 months after augmentation procedure | 
| Change in Oral Health impact profile OHIP-14 | To be filled in i)at patient enrolment prior to delivering any interventions, ii)12 weeks after delivery of the definitive prostheses and iii) 1, 3, 5, 7, 10 and 15 years after loading. Patients' number of days with total or partial impaired activity assessed at delivery of the provisional prosthesis A days of total impaired activity is one where patient is unable to perform his/her ordinary life activity including work. A days of partial impaired activity is one where the patient is only partially able to perform his/her ordinary life activity including work. | 1,3,5,7,10,15 | 
| Complications | Biologic and prosthetic complications will be assessed. Biologic complications include perimplantitis, maxillary sinusitis, abscess, fistula, gingival dehiscence Prosthetic complication: abutment fracture | 3 years | 
| Complications | Biologic and prosthetic complications will be assessed. Biologic complications include perimplantitis, maxillary sinusitis, abscess, fistula, gingival dehiscence Prosthetic complication: abutment fracture | 5 years | 
| Complications | Biologic and prosthetic complications will be assessed. Biologic complications include perimplantitis, maxillary sinusitis, abscess, fistula, gingival dehiscence Prosthetic complication: abutment fracture | 7 years | 
| Complications | Biologic and prosthetic complications will be assessed. Biologic complications include perimplantitis, maxillary sinusitis, abscess, fistula, gingival dehiscence Prosthetic complication: abutment fracture | 10 years | 
| Complications | Biologic and prosthetic complications will be assessed. Biologic complications include perimplantitis, maxillary sinusitis, abscess, fistula, gingival dehiscence Prosthetic complication: abutment fracture | 15 years |