Silicone implants for augmentation mammoplasty were first introduced in 1962 (1,2). Since then, they have undergone many changes in terms of design and materials. There have been at least five generations of silicone implants to date, each using a different combination of core material and shell type (3). Each subsequent generation of silicone implants was introduced in an attempt to improve their aesthetic quality and feel, and to reduce their complication rates. Cohesive gel implants were introduced in 1993 and represent the latest generation of silicone breast implants on the market today (3).Despite many improvements in breast implant design and surgical technique, capsular contracture continues to be a significant problem. Reported rates of clinically significant capsular contracture are between 15% and 45% (2-5), with 92% of these occurring in the first year after surgery (6). A recent meta-analysis (6) found surface texturing to be protective against capsular contracture in patients with breast implants placed in the subglandular position. There has been no meta-analysis to date looking at the effect of breast implant core type on rates of capsular contracture.In 1992, the United States Food and Drug Administration announced a moratorium on the use of silicone breast implants, citing their possible link to rheumatic diseases and breast cancer (1). Since then, evidence has amassed discrediting these claims (7-12) and on November 16, 2006, silicone INTRoduCTIoN: Capsular contracture after augmentation mammoplasty occurs at a rate of 15% to 45%. The purpose of the present study was to determine the effect of implant core type (silicone versus saline) on the rate of capsular contracture in augmentation mammoplasty. METHodS: A systematic review was conducted through a search of three electronic databases. Two reviewers independently scanned titles yielded by the search and identified potentially relevant papers. Interreviewer variability and the scientific quality of the articles were assessed. Meta-analysis was performed. RESulTS: Eighty-eight titles of potential relevance were selected from the 393 articles yielded by the search. Inter-rater agreement for selection of potentially relevant articles was 84% (k=0.54). Four comparative studies were included in the analysis. Scientific quality scores of the included studies ranged from 5 of 14 to 9 of 14. Three of the four studies reported a higher rate of capsular contracture in patients with silicone implants. A combined odds ratio calculated on two of the studies found a 2.25-fold increased risk of capsular contracture in patients who received silicone implants. Eight series of patients who received cohesive gel silicone implants reported rates of capsular contracture from 0% to 13.6%. CoNCluSIoNS: Higher rates of capsular contracture were found in patients who received silicone implants when compared with those who received saline implants. However, the scientific quality of the comparative studies to date on this subject is poor. Recent series evaluating...