Objectives To compare the periodontal and peri-implant conditions of Chinese patients with a history of moderate or severe periodontitis and periodontally healthy patients (PHP); to evaluate the influence of maintenance therapy frequency on the outcome of implant therapy. Methods Results A total of 140 participants with 227 sand-blasted acidetched (SLA) implants were divided into three groups: PHP, moderate periodontally compromised patients (PCP) and severe PCP. The three groups were further categorized into two groups based on the frequency of maintenance (MF): MF >= 1 per year and MF < 1 per year. The following clinical parameters of implants were assessed: implant survival/loss, peri-implant probing depth (PDi), peri-implant bleeding index (BIi), peri-implant bleeding on probing (BOPi), implant bone loss (BLi). Comparisons of the peri-implant conditions were performed between the patients with different periodontal conditions. Implant survival rate was 100% for all three groups. The severe PCP group showed significantly higher deepest PDi, mean PDi, mean BIi, and PLIi compared with PHP (p < 0.05). The severe PCP group had more implants affected with PDi >= 5 mm and BOPi+ compared with the PHP group (Adjusted OR = 10.89, 95% CI: 2.34, 50.74). In the patients with severe PCP, the MF < 1 per year group had a greater prevalence of PDi >= 5 mm and BOPi+ compared with the MF >= 1 per year group (Adjusted OR = 8.23, 95% CI: 2.44, 27.78). Conclusions The patients in the severe PCP group were at greater risk of peri-implant disease than those in the PHP group. In particular, severe PCP who had poor adherence to maintenance care showed a higher incidence of biologic complications.