Introduction: The efficiency of routine scaling and root planning is negatively influenced by the tooth anatomy and residual bacteria all possibly affecting the treatment outcomes in future. The present study compared the microbiologic effectiveness of the photodynamic therapy (PDT) as an adjunctive treatment modality for nonsurgical treatment in chronic periodontitis. Methods: In this randomized controlled clinical trial, 18 chronic periodontitis patients were selected. Four quadrants were randomly treated by scaling and root planning (SRP), diode laser (810n m wavelength, 1.5 W and 320 µm fiber, contact and sweeping technique), SRP + PDT (with diode laser 808 nm, 0.5 W) and laser + SRP (with diode laser 808 nm, 1 W) in each patient. Presence of periodontal pathogen species in the treated areas were measured before the treatment, at 1 and 3 months afterwards. The identification and reproduction of the specific genes of pathogen bacteria were done by means of polymerase chain reaction (PCR) technique. Presence of oral pathogen bacteria in the treatment groups were analyzed by chi-square test. A semi quantitative analysis was used to measure the intensity of white light in each band. This was calculated by number of pixels in each band. Results: In the qualitative analysis, Fusobacterium nucleatum (Fn) and Treponema denticola (Td) species were killed after 1 month in all treatment modalities. PDT had more effects to decrease Prevotella intermedia (Pi) species than SRP while Tannerella forsythensis count (Tf) species increased in all treatments. Furthermore, Actinobacillus actinomycetemcomitans (Aa) species decreased in all treatments and Porphyromonas gingivalis (P.g) species increased in all treatments after 1 and 3 months. Conclusion: It can be concluded that PDT was more effective as an adjunctive treatment to SRP than SRP alone; however, no distinct differences were found between both treatment modalities regarding reduction of certain pathogen bacteria.

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Fissure sealant application is an efficient method for dental caries prevention. Self-etch fissure sealants (SE-FS) eliminate the separate etching step for bonding. The present study investigated the micro-shear bond strength (μSBS) of a SE-FS (Prevent seal ® , Itena©, Paris, France) to enamel pretreated with different methods including Er,Cr:YSGG laser, under noncontaminated and saliva-contaminated conditions. Sixty human premolars were sectioned into halves and randomly assigned into two groups of saliva-contaminated and noncontaminated. Each group was further divided into six subgroups (N = 10) of different enamel pretreatment methods: (Laser+SE-FS), (Acid-etch+SE-FS), (Laser+Acid-etch+SE-FS), (Mechanical preparation+SE-FS), (SE-FS), and (Acid-etch+Bonding+Conventional fissure sealant) as positive control. The μSBS of the sealant material to enamel was measured in all subgroups. The two-way ANOVA and Tukey tests were applied at P < 0.05. Saliva contamination had a significant effect on μSBS (P < 0.001), while pretreatment with laser or acid etching did not significantly affect the μSBS (P = 0.251). The μSBS of SE-FS to untreated enamel surface was significantly lower than the positive control (P = 0.035). The μSBS value in the subgroup receiving laser+etching+SE-FS was significantly higher than the remaining five subgroups (P < 0.001). Other pairwise comparisons were not statistically significant (P > 0.05). Acidetch and Er,Cr:YSGG laser exert a synergic effect on μSBS of Prevent Seal ® , irrespective of saliva contamination.