Antimicrobial photodynamic therapy (aPDT) is an evolving treatment modality where light of a particular wavelength is used to excite a specific photosensitizer (PS) that mediates bacterial destruction. Randomized controlled trial of aPDT in the management of chronic periodontitis shows the potential of this treatment in improving clinical, patient-based and microbial parameters in the test group as compared to control group and therefore can be proposed as an adjunct to conventional scaling and root planning in order to improve treatment results of chronic periodontitis. Furthermore, for the first time, laser induced autofluorescence spectra recorded in situ from dental plaque accumulated on tooth surface shows the applicability of this technique in discrimination between various grades of plaque clinically.