Which type of bacteria is commonly associated with infected implant sites?

The correct answer is that anaerobic rods are commonly associated with infected implant sites. These bacteria thrive in low-oxygen environments, which are often created around dental implants due to the surgical placement and subsequent healing processes. Infected implant sites typically present with a microenvironment that supports the growth of anaerobic organisms, leading to infection.

Anaerobic rods, such as those from the Bacteroides and Fusobacterium genera, can actively contribute to the development of peri-implantitis and other complications associated with implants. This is because they can evade the immune system more effectively in oxygen-depleted areas, resulting in a more difficult situation for healing and recovery.

In contrast, aerobic rods, while they also play a role in various infections, are more adapted to environments with ample oxygen, making them less prevalent in the deeper spaces around infected implants. Streptococcus mutans and Streptococcus sanguis are primarily associated with dental caries and plaque formation but are not the predominant bacteria found in infections surrounding implants. These bacteria are facultative or aerobic and typically thrive in oral environments that include oxygen, differing from the typical conditions seen at infected implant sites.