Short Implants - An Alternative to Bone Grafting?

Study Overview
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Brief Summary
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The study, with the ASTRA TECH Implant System, is comparing short implants (OsseoSpeed™) to standard length implants (OsseoSpeed™) in combination with bone grafting. The hypothesis is that the use of short implants in posterior maxilla with inadequate bone is as safe and predictable as placing standard length implants in combination with bone augmentation.

Detailed Description
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This study was designed as an open, prospective, randomized, controlled, multicenter, 5-year follow-up investigation evaluating the outcome of treatment with the OsseoSpeed™ implant 6 mm placed in the posterior maxilla compared to treatment with OsseoSpeed™ implant 11, 13 or 15 mm placed after bone grafting. The study was during the conduct of the study amended to include a 10-year extension cohort.

Official Title
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Study on ASTRA TECH Implant System, Short Implants (OsseoSpeed™) Compared to Standard Length Implants (OsseoSpeed™) in Combination With Bone Grafting

Conditions
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Jaw, Edentulous, Partially

Intervention / Treatment
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* Device: ASTRA TECH Implant System, OsseoSpeed™ 4.0 S (length: 6 mm)
* Device: ASTRA TECH Implant System, OsseoSpeed™ implants (lengths: 11, 13, 15 mm) in combination with bone grafting


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Provision of informed consent Aged 20-75 years at enrolment History of edentulism in the study area of at least four months In need for 1-4 implants in either side of the posterior maxilla (premolar and molar region) Neighboring tooth/teeth to the planned implant/s must have natural root(s) or implant supported restoration, with absence of pathology or excessive bone loss, as judged by the investigator Presence of natural tooth/teeth, partial prosthesis and/or implants in the opposite jaw in contact with the planned crown/s Deemed by the investigator to have a bone height between 5 and 7 mm and a bone width of a minimum of 6 mm Deemed by the investigator as likely to present an initially stable implant situation Exclusion Criteria: Unlikely to be able to comply with study procedures, as judged by the investigator Earlier bone graft procedures in the study area Uncontrolled pathologic processes in the oral cavity Known or suspected current malignancy History of radiation therapy in the head and neck region History of chemotherapy within 5 years prior to surgery Systemic or local disease or condition that could compromise post-operative healing and/or osseointegration Uncontrolled diabetes mellitus Corticosteroids, iv bisphosphonates or any other medication that could influence post-operative healing and/or osseointegration Smoking more than 10 cigarettes/day Bruxism Present alcohol and/or drug abuse Involvement in the planning and conduct of the study (applies to both Astra Tech staff and staff at the study site) Previous enrolment in the present study Simultaneous participation in another clinical study

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

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 |
| --- | --- |
| Experimental: Short Implants<br>ASTRA TECH Implant System, OsseoSpeed™ 4.0 S (length: 6 mm) | Device: ASTRA TECH Implant System, OsseoSpeed™ 4.0 S (length: 6 mm)<br>* ASTRA TECH Implant System, OsseoSpeed™ 4.0 S (length: 6 mm)<br>|
| Active Comparator: Long Implants in combination with bone grafting<br>ASTRA TECH Implants System, OsseoSpeed™ implants (lengths: 11, 13, 15 mm) in combination with bone grafting | Device: ASTRA TECH Implant System, OsseoSpeed™ implants (lengths: 11, 13, 15 mm) in combination with bone grafting<br>* ASTRA TECH Implant System, OsseoSpeed™ implants (lengths: 11, 13, 15 mm) in combination with bone grafting<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Implant Survival Rate | Any implant that is removed after implant placement will be considered a failure, whatever the reason for removal. Implant survival will be evaluated clinically and radiographically by counting the number of remaining implants. Implant survival rate will be calculated by dividing the number of non-failures by the number of installed implant. | 5 years after permanent restoration | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Average Marginal Bone Level (MBL) Change From Permanent Restoration on Implant Level | Marginal bone level will be determined from radiographs and expressed as the distance from a reference point on the implant to the most coronal bone-to-implant contact on the mesial and distal aspect of the implant. Marginal bone level expressed in millimetres at the 5 year follow-up visit will be compared to values obtained at delivery of permanent restoration. Positive value denotes gain of bone. Negative value denotes loss of bone. | Time of permanent restoration and 5 years after permanent restoration | 
| Average Marginal Bone Level (MBL) Change From Permanent Restoration on Implant Level | Marginal bone level will be determined from radiographs and expressed as the distance from a reference point on the implant to the most coronal bone-to-implant contact on the mesial and distal aspect of the implant. Marginal bone level expressed in millimetres at the 10 year follow-up visit will be compared to values obtained for the 10-years cohort at delivery of permanent restoration. Positive value denotes gain of bone. Negative value denotes loss of bone. | Time of permanent restoration and 10 years after permanent restoration | 
| Condition of Periimplant Mucosa Measured Through Bleeding on Probing (BoP) | Bleeding on Probing will be evaluated at four aspects per implant, i.e. mesially, distally, buccally and palatinally by using a periodontal probe. BoP will be recorded as presence or absence (Yes or No) of bleeding when probing to the bottom of the pocket. The proportion of surfaces that show presence of bleeding will be calculated and presented on a subject level. | 5 years after permanent restoration | 
| Condition of Periimplant Mucosa Measured Through Bleeding on Probing (BoP) | Bleeding on Probing will be evaluated at four aspects per implant, i.e. mesially, distally, buccally and palatinally by using a periodontal probe. BoP will be recorded as presence or absence (Yes or No) of bleeding when probing to the bottom of the pocket. The proportion of surfaces that show presence of bleeding will be calculated and presented on a subject level for the 10-years extension cohort. | 10 years after permanent restoration | 
| Condition of Periimplant Mucosa Measure by Average Change in Probing Pocket Depth (PPD) From Permanent Restoration | PPD will be measured as the distance from the mucosal margin to the bottom of the probeable pocket in mm. A mean value will be calculated for each implant as well as for each subject. PPD changes in millimetres at the 5 year follow-up visit will be compared to values obtained at delivery of permanent restoration. Negative value denotes deeper pocket depth. | Time of permanent restoration and 5 years after permanent restoration | 
| Condition of Periimplant Mucosa Measure by Average Change in Probing Pocket Depth (PPD) From Permanent Restoration | PPD will be measured as the distance from the mucosal margin to the bottom of the probeable pocket in mm. A mean value will be calculated for each implant as well as for each subject. PPD changes in millimetres at the 10 year follow-up visit will be compared to values obtained at delivery of permanent restoration. Negative value denotes deeper pocket depth. | Time of permanent restoration and 10 years after permanent restoration | 
| Change in Overall Oral Health Impact Profile (OHIP-49) | OHIP-49 is describing the consequences of different oral diseases and conditions. It contains 49 items (questions) divided into 7 domains which are; functional limitation, pain, psychological discomfort, physical disability, psychological disability, social disability, and handicap. OHIP-49 attempts to measure both the frequency and severity of oral problems on functional and psychosocial well-being. Responses are based on a Likert response, with scale range; 0 = never, 1 = hardly ever, 2 = occasionally, 3 = fairly often, 4 = very often, for each of the 49 questions with a higher score being related to a worse outcome. To facilitate assessment of perceived severity of impacts, each statement has a weight derived using the Thurstone's paired comparison technique to reflect the relative importance of each statement. The overall OHIP-49 include all 49 questions with a total minimum score of 0 and a maximum total score of 196, with a higher score being related to a worse outcome. | At baseline (Visit 1 - screening and pre-surgical planning visit) and 5 years after permanent restoration | 
| Change in Overall Oral Health Impact Profile (OHIP-49) | OHIP-49 is describing the consequences of different oral diseases and conditions. It contains 49 items (questions) divided into 7 domains which are; functional limitation, pain, psychological discomfort, physical disability, psychological disability, social disability, and handicap. OHIP-49 attempts to measure both the frequency and severity of oral problems on functional and psychosocial well-being. Responses are based on a Likert response, with scale range; 0 = never, 1 = hardly ever, 2 = occasionally, 3 = fairly often, 4 = very often, for each of the 49 questions with a higher score being related to a worse outcome. To facilitate assessment of perceived severity of impacts, each statement has a weight derived using the Thurstone's paired comparison technique to reflect the relative importance of each statement. The overall OHIP-49 include all 49 questions with a total minimum score of 0 and a maximum total score of 196, with a higher score being related to a worse outcome. | At baseline (Visit 1 - screening and pre-surgical planning visit) and 10 years after permanent restoration |