Objectives: This research was carried out to evaluate the effect of bio-modulation with Er,Cr:YSGG LASER on peri-implant crestal bone level changes in cases having edentulous mandible opposed with maxillary natural teeth rehabilitated with fixed detachable prosthesis constructed from BioHPP using CAD/CAM technology. Materials and Methods: This is a split mouth design study in which ten male patients exhibiting completely edentulous mandibular arch opposed by dentate maxillary arch were rehabilitated with fixed detachable lower single denture supported by six dental implants constructed from BioHPP Results: This study showed that there was a statistically significant increase in crestal bone height loss around the implants in both groups.Conclusion: Within the limitation of this study findings, it seems reasonable to suggest that patient compliance, control of occlusal load, primary implant stability, good oral hygiene and passive fit are important factors for the long term success of fixed detachable lower single denture designed by CAD/CAM rather than the additional use of low level laser therapy.