The long-term evaluation of the prognosis of implants with acid-etched surfaces sandblasted with alumina: a retrospective clinical study
By: Min-Joong Kim, Pil-Young Yun, Na-Hee Chang and Young-Kyun Kim
The aim of this study was to evaluate the long-term clinical stability of implants with acid-etched surfaces sandblasted with alumina using retrospective analyses of the survival rate, success rate, primary and secondary stability, complications, and marginal bone loss of the implants.
Materials & Methods:
Study design : Retrospective clinical study
Subjects and Outcomes of the study
Patients : 45 Patients who had implants placed (TS III SA, SS II SA,SS III SA, and U III SA) with SA surfaces from Osstem at the Seoul National University Bundang Hospital, from January 2008 to December 2010
Implants : 96 implants
96 implants were placed in 45 patients. Five implants were removed during the follow-up period for a total survival rate of 94.8%.
Survival rate according to implant type
Sixty-four TS SA implants were placed in 29 patients with 62 implants (97%) surviving. Twenty-two SS SA implants were placed in 12 patients and 21 implants (95%) survived. Ten US SA implants were placed in 4 patients and 8 implants (80%) survived.
|Table 1. Survival rates of implants|
|Survival rate (%)||Failure (n)|
|TS SA||implant 62/64 (97%)||2|
|SS SA||implant 21/22 (95%)||1|
|US SA||implant 8/10 (80%)||2|
|Average||91/96 (94.8%)||Total, 5|
|The p value between the TS SA implant group and the SS SA implant group was 0.963, the p value between the SS SA implant group and the US SA implant group was 0.067, and the p value between the TS SA implant group and the US SA implant group was 0.161. There was no significant difference between the other groups.|
Marginal bone loss
The average bone loss at 1 year after completion of the prosthesis was 0.37 mm, and the average bone loss at final observation was 0.5 mm. The mean marginal bone resorption after 1 year of loading and final observation in each group was 0.37 mm, 0.51mm for TS SA implants, 0.16 mm, 0.32mm for SS SA implants, and 0.43mm, 0.58mm for US SA implants.
|Table 2. Marginal bone loss (mm)|
|1 year after loading||Final observation||More than 1mm within 1 year (n)|
|TS SA implant||0.37mm||0.51mm||10|
|SS SA implant||0.16mm||0.32mm||0|
|US SA implant||0.43mm||0.58mm||0|
|There was a statistically significant difference between the TS SA implant group and the SS SA implant group (p = 0.038). However, the p value between the SS SA implant group and the US SA implant group was 0.815, and the p value between the TS SA implant group and the US SA implant group was 0.575. There was no significant difference between the other groups.|
Survival rate and marginal bone loss according to implant diameter
One case failed at 3.5mm in diameter, two cases at 4.0mm in diameter, and one case at 4.5mm in diameter. The average final marginal bone loss was 4.0mm > 3.5mm > 4.5mm > 5.0mm > 4.1mm > 4.8 mm.
Survival rate and marginal bone loss according to implant length
Survival failures were found in 1 case 7.0mm in length, 2 cases 10.0 mm in length, and 2 cases 13.0mm in length. The final marginal bone loss was 8.5mm > 13.0 mm > 10.0 mm, 11.5 mm > 7.0 mm.
Analysis of factors that influenced implant failure
There were 5 cases of implants that failed to survive during the observation period. There was a significant correlation (p < 0.05) between survival and complications, and more than 1mm of bone loss within 1 year after completion of the prosthesis.
|Table 3. Correlation between factors (*p < 0.05)|
|Survival||Bone resorption of 1mm or more within 1 year||Implant placement method|
|Occurrence of complications||* (R = 0.545, p = 0.01)||* (R = 0.447, p = 0.01)||* (R = 0.26, p = 0.02)|
|Bone resorption of 1mm or more within 1 year||* (R = 0.53, p = 0.02)||–||–|
|Initial stability less than 60||–||* (R = 0.274, p = 0.01)||–|
|Presence of bone grafting||–||–||–|
|Implant installation method||–||* (R = 0.251, p = 0.014)||–|
|R correlation coefficient, p p value|
Of the 96 cases, 5 implants failed resulting in a 94.8% survival rate. The failed implants were all cases of early complications such as infection, failure of initial osseointegration, and early exposure of the fixtures. Periimplantitis was mostly addressed through conservative and/or surgical treatment and resulted in very low prosthetic complications. Therefore, if preventive measures are taken to minimize initial complications, the results can be very stable.