Influence of an 810-nm Diode Laser on the Temperature Changes of the External Root Surface: An In Vitro Study

Comparative evaluation of postoperative pain and tissue response in patients undergoing conventional flap surgeries with or without 940 nm diode laser exposure - A randomized clinical study

BACKGROUND

Over the past few years, a growing body of evidence has allowed us to ascertain that the initiation of periodontitis stems from the existence of oral microbial biofilm and that this requires definitive treatment. Owing to its exceptional usability, affordability, and antibacterial activity, the "diode laser" (DL) has increasingly become a popular and important tool in a dentist's armamentarium. However, there is a scarcity of scientific evidence on the utility and advantages of using "diode laser" in periodontal flap surgery. The study aimed to determine the efficacy of 940 nm diode laser exposure in combination with conventional periodontal flap surgery for the treatment of chronic periodontitis to evaluate postoperative discomfort and clinical parameters.

MATERIALS AND METHODS

A total of 10 subjects (7 males and 3 females) with generalized chronic periodontitis were recruited and completed the study without any dropouts. For this split-mouth study, 40 sample sites with pocket probing depth (PPD) 5-7 mm post periodontal Phase I therapy were selected. The quadrants were randomly allocated to Groups A, B, C, and D using the fish bowl lottery method. Kirkland flap surgery with laser and modified Widman flap (MWF) with laser were performed in Group A and C, respectively, while Kirkland flap surgery and MWF surgery were performed in Group B and Group D. Clinical parameters including visual analog scale (VAS) score and gingival inflammation were determined at 3^rd and 7^th day postoperatively while PPD, clinical attachment level (CAL), and sulcus bleeding index (SBI) were recorded at baseline and 6 months following treatment. Wilcoxon signed-rank test and Kruskal-Wallis test were used for intra-group and inter-group comparison of parameters, respectively.

RESULTS

Statistically significant difference was attained with postoperative discomfort in laser-assisted groups on 1^st and 3^rd day postoperatively (P < 0.001). There was no significant difference in the proportion of subjects with gingival inflammation. A statistically significant reduction in mean PPD at 6 months postoperatively was seen among all study groups (P < 0.05) but the inter-group difference was not statistically significant. SBI score reduced significantly from baseline to 6 months follow-up among all four groups (P < 0.05). However, we did not find the inter-group difference to be statistically non-significant.

CONCLUSION

Diode laser as an adjunct to the surgical procedure can demonstrate appreciable benefits by increasing the CAL and minimizing the postoperative pain and the probing pocket, but such additional effects were not observed with gingival inflammation.

Effect of low-power diode laser on infected root canals

This study evaluated the effect of photodynamic therapy (PDT) on infected root canals. Twenty-one human teeth were selected, and 18 were infected by E. faecalis for 60 days. The antimicrobial strategies tested were: G1. Root canal preparation (RCP) using Niquel-Titanium (NiTi) rotary instruments, 2.5% NaOCl, and final irrigation with 17% EDTA, followed by PDT with methylene blue photosensitizer and laser diode low power; G2. RCP using stainless steel files and the same irrigation and PDT protocols as G1; G3. Same RCP protocol as G1 without PDT; G4. Only irrigation with 2.5% NaOCl; G5. Same PDT protocol as G1 without RCP; G6. Negative control; G7. Positive control. Samples for microbiological tests were collected initially (S1), after RCP (S2), and after PDT (S3). Subsequently, the roots were sectioned and prepared for Scanning Electron Microscopy (SEM) analysis. Bacterial growth was analyzed according to the turbidity of the culture medium, followed by spectrophotometric optical density (nm). The effect of PDT on the dentinal structure was evaluated at magnifications 1,600X and 5,000X and described qualitatively. The Wilcoxon test was used for the comparisons from the same specimens, and the Mann-Whitney test was used to compare groups ((=5%). Bacteria were found in all experimental groups' microbiological samples (S1, S2 and S3). The optical density of culture media was lower in S2 than in S1 of G1, 2, 3, and 4 (p> 0.05). After PDT (S3) in G1 and 2, there was an additional reduction in optical density of the culture medium, respectively (p>0.05). In Group 5, the analysis of culture media at S2 revealed an increase in optical density compared to S1(p>0.05). In SEM images of G1, 2, and 5, dentin with melting and recrystallization areas were evidenced. After preparation of the root canal with the rotary system or manually associated with 2.5% NaOCl, PDT was not able to completely eliminate E. faecalis present in the root canal.