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.

Outcome measure only applicable for the initial study (5 years) cohort.

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.

Initial study (5 years) cohort. At visit 10 (5-year follow-up visit) 44 subjects remained in the short implants group, and 46 subjects remained in the long implants group. 10 subjects within the short implants group had missing or unreadable radiographs and could thus not be included in the analysis. The corresponding number for long implants group was 9 subjects with missing and unreadable radiographs.

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.

Follow-up Extension (10 years) cohort. At visit 15 (10-year follow-up visit) 29 subjects remained in the short implants group, and 32 subjects remained in the long implants group. 7 subjects within the short implants group had missing or unreadable radiographs and could thus not be included in the analysis. The corresponding number for long implants group was 9 subjects with missing and unreadable radiographs.

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.

Initial study (5 years) cohort. At visit 10 (5-year follow-up visit) 44 subjects remained in the short implants group, and 46 subjects remained in the long implants group. All subjects were included in the Intention-To-Treat population and were included in the analysis of 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.

Follow-up Extension (10 years) cohort. At visit 15 (10-years follow-up visit) 29 subjects remained in the short implants group, and 32 subjects remained in the long implants group. All subjects were included in the ITT population and were included in the analysis of BoP.

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.

Initial study (5 years) cohort. At visit 10 (5-year follow-up visit) 44 subjects remained in the short implants group, and 46 subjects remained in the long implants group. One subject in the short implants group did not have baseline PPD and was not included in the PPD analysis.

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.

Follow-up Extension (10 years) cohort. At visit 15 (10-year follow-up visit) 29 subjects remained in the short implants group, and 32 subjects remained in the long implants group. All subjects were included in the ITT population and were included in the analysis of PPD.

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.

Initial study (5 years) cohort. At visit 10 (5-year follow-up visit) 44 subjects remained in the short implants group, and 46 subjects remained in the long implants group. All subjects with available OHIP-values from baseline and 5 years after permanent restoration were included in the analysis of overall 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.

Follow-up Extension (10 years) cohort. At visit 15 (10-year follow-up visit) 29 subjects remained in the short implants group, and 32 subjects remained in the long implants group. All subjects with available OHIP-values from baseline and 10 years after permanent restoration were included in the analysis of overall OHIP-49.