The antibacterial effect of chlorohexidine, Er:YAG laser and diode laser 980nm as dental cavity disinfectants of dentine: an in vitro study.

The study aimed to assess and compare the cavity disinfection efficacy of 2% chlorhexidine, 940 nm diode laser, and photodynamic therapy (PDT) with Rose Bengal-functionalized chitosan nanoparticles (CS-NPs) in deep carious lesions. This randomized controlled, parallel clinical trial was conducted in the Department of Conservative Dentistry and Endodontics, Government Dental College and Hospital, Ahmedabad. A simple randomization technique was used for randomization of samples. A total of 90 patients participated in this study. Ninety participants with reversible pulpitis were randomly assigned to three groups, each receiving a different cavity disinfectant: 2% chlorhexidine, 940 nm diode laser, and PDT with Rose Bengal-functionalized CS-NPs. Dentinal samples were collected before and after cavity disinfection, and microbiological analysis for total viable count (TVC), Streptococcus mutans, and Lactobacillus count was conducted. Clinical and radiographic evaluation was done at 1 and 6 months. Statistical analysis involved the Wilcoxon signed-rank, Kruskal-Wallis, and Tukey's tests. Intragroup comparison showed high significant reductions in TVC, S. mutans, and Lactobacillus count in all the groups. The Kruskal-Wallis test revealed that the chlorhexidine group had the greatest reduction in bacterial counts, followed by PDT and diode laser groups. No differences in clinical success rates were observed among the three groups up to 6-month follow-up. All three cavity disinfectants significantly reduced total vital count, S. mutans, and Lactobacillus count. However, chlorhexidine showed the best results.

Effects of photodynamic therapy with indocyanine green on Streptococcus mutans biofilm.

Laser treatment has become a popular method for resolving peri-implantitis, but the full range of its effects on implant surfaces is unknown. The purpose of the present investigation was to analyze the influence of different clinically applicable erbium:yttrium-aluminum-garnet (Er:YAG), carbon dioxide (CO2), and diode laser parameters on titanium surfaces that were either polished or sandblasted, large-grit, acid-etched (SLA). Six polished and six SLA titanium disks were irradiated at nine different power settings (n = 54 polished, 54 SLA) with Er:YAG, CO2, or diode lasers. The CO2 and diode lasers were used in continuous wave mode, and the Er:YAG laser was used in a pulsed manner. The surface of each disk was analyzed by scanning electron microscopy and confocal white light microscopy. Each disk was irradiated on six circular areas of 5 mm in diameter with the same specific laser setting for 10 seconds. Within the chosen parameters, the CO2 and diode laser did not cause any visible surface alterations on either the polished or SLA disks. In contrast, both polished and SLA disks showed surface alterations when irradiated with the pulsed Er:YAG laser. The SLA surfaces showed alteration after 10 seconds of irradiation with Er:YAG laser at 300 mJ/10 Hz. The surfaces of the polished disks did not show alteration with the Er:YAG laser until they were irradiated at the higher energy of 500 mJ/10 Hz for 10 seconds. The results of confocal white light microscopy were in agreement with scanning electron micrographs. In contrast to continuous-wave diode and CO2 laser irradiation, pulsed Er:YAG laser irradiation caused distinct alterations with power settings beyond 300 mJ/10 Hz on the SLA surface and 500 mJ/10 Hz on the polished surface. Thus, it is only safe to use the Er:YAG laser for implant surface irradiation with settings no higher than 300 or 500 mJ/10 Hz.

Aim:The aim of this study was to investigate and compare the antimicrobial effects of an 810-nanometer diode laser, utilizing or not utilizing toluidine blue as a photosensitizer, in the management of peri-implant mucositis.Settings and Design:The present study was carried out in 30 implant sites in 15 patients with peri-implant mucositis with a specific inclusion and exclusion criteria. 15 sites were treated utilizing a diode laser (control group) and 15 with photodynamic therapy (test group) in a split-mouth format.Materials and Methods:Samples were taken from the gingival sulcus with the help of plastic curettes from control and test sites both at baseline and at 3 months for microbiological analysis.Statistical Analysis Used:Shapiro-Wilk Test was used to check deviation from normality. Wilcoxon signed-rank test was used to analyse the two dependent groups.Results:Intragroup comparison was found to be statistically significant when compared at baseline and at 3 months in the photodynamic (P = 0.001) and diode laser groups (P = 0.001), respectively. No statistically significant reduction in bacterial count was found at baseline (P = 0.1) and at 3 months (P = 0.5) when the diode laser group and photodynamic group were compared with each other (intergroup).Conclusion:Within the limitations of the study, it can be concluded that there is a definitive reduction in pathogenic bacteria with both interventions and PDT offers clinically visible benefits in the treatment of peri-implant mucositis.

This study aimed to investigate the ability of the diode and Nd:YAG lasers to decrease postoperative pain/discomfort after intracanal application in vital and devital endodontic cases. One hundred two patients with symptomatic irreversible pulpitis and asymptomatic necrotic pulps were selected and randomly divided into three groups. After chemomechanical preparation, Nd:YAG and diode laser was applied to first and second groups for final treatment of the root canals. In the control group, no further disinfection protocol was performed upon traditional procedures. Then all the teeth were obturated in the same appointment. Pre- and postoperative pain were recorded using the VAS at 0, 12th, 24th, 48th, and 72nd hours following the treatment Kruskal-Wallis and Dunn test. VAS scores were significantly the most at 12-h period compared with other time periods after treatment for all groups. There was no significant difference among Nd:YAG laser, diode laser, and control groups in non-vital cases (p > 0.05). In vital cases, Nd:YAG laser group represented significantly fewer scores compared with diode laser and control groups at 48-h period (p < 0.05). The processes involving the use of Nd:YAG and diode lasers after chemomechanical preparation was found to be equivalent in terms of postoperative pain intensity after completion of treatment in one session both in vital or non-vital cases except in vital cases in Nd:YAG group at 48 h. Adjunct clinical use of Nd:YAG or diode lasers to traditional chemomechanical preparation did not cause any improvement or deterioration on postoperative discomfort and pain in patients with symptomatic irreversible pulpitis and asymptomatic necrotic pulps.

BackgroundDental caries remains one of the most common chronic conditions worldwide, often requiring treatment that balances effective bacterial control with preservation of healthy tooth structure. In recent years, researchers have explored novel antimicrobial approaches that can be used during minimally invasive caries treatments. Various adjunctive methods have been employed to inhibit the growth of residual bacteria in deep carious lesions. While chemical disinfectants have demonstrated notable antibacterial properties, their effectiveness can be compromised by some side effects, including adverse interactions with restorative materials and potential alterations to dental tissue structure. Consequently, there is a growing need for alternative antibacterial approaches. Among the latest advancements in cavity disinfection are diode lasers and zinc oxide nanoparticles.AimConsidering the limited number of clinical studies investigating both agents as cavity disinfectants, the primary aim of the present clinical trial was to evaluate the antibacterial effectiveness of a diode laser (976 nm) and zinc oxide nanoparticles in an ethanol-based solution against cariogenic bacteria, specifically Streptococcus mutans, when applied as cavity disinfectants.Materials and methodsThirty patients with deep cervical carious lesions were randomized into two groups (n = 15). After selective caries removal, baseline carious dentin samples were collected (control). One group received cavity disinfection using a 976 nm diode laser at 1.3 W output, while the other was treated with zinc oxide nanoparticles (50 μg/mL ethanol-based solution). Zinc oxide nanoparticles were prepared and characterized using transmission electron microscopy and X-ray diffraction to confirm morphology and crystallinity. Post-intervention dentin samples were collected via colony-forming units (CFU) for microbiological analysis.ResultsTransmission electron microscopy revealed spherical zinc oxide nanoparticles with diameters averaging 18 nm. X-Ray diffraction confirmed high crystallinity. Both the laser diode and zinc oxide nanoparticles groups showed significant reductions in colony forming unit post-disinfection (p < 0.001). The diode laser group had significantly higher colony forming unit (mean: 8.27 ± 0.80 CFU/mL) compared to the zinc oxide nanoparticles group (mean: 3.47 ± 0.74 CFU/mL). Percentage of bacterial reduction was lower in the laser diode group (93.77%) than the ZnO NPs group (97.4%).ConclusionSpherical-shaped zinc oxide nanoparticles with particle sizes around 25 nm and 50 μg/mL concentration in ethanol-based solution demonstrated superior antibacterial efficacy, suggesting they are a promising alternative for cavity disinfection in conservative caries management.Clinical significanceThe results of the trial open new possibilities for improving patient outcomes by integrating more targeted and conservative disinfection options into everyday dental practice.Clinical trial registrationThis study was registered on clinical trial (www.ClinicalTrials.gov).

The aim of the present study was to compare the effects of Er:YAG and diode laser treatments of the root surface on intrapulpal temperature after scaling and root planing with hand instruments. Fifteen extracted single-rooted teeth were scaled and root planed with hand instruments. The teeth were divided into 3 groups of 5 each and irradiated on their buccal and lingual surfaces: group A: Er:YAG laser, 2.94 microm/100 mJ/10 Hz/30 seconds; group B: diode laser, 810 nm/1.0 W/0.05 ms/30 seconds; group C: diode laser, 810 nm/1.4 W/0.05 ms/30 seconds. The temperature was monitored by means of a type T thermocouple (copper-constantan) positioned in the pulp chamber to assess pulpal temperature during and before irradiation. Afterwards, the specimens were longitudinally sectioned, and the buccal and lingual surfaces of each root were analyzed by scanning electron microscopy. In the Er:YAG laser group, the thermal analysis revealed an average temperature of -2.2 +/- 1.5 degrees C, while in the diode laser groups, temperatures were 1.6 +/- 0.8 degrees C at 1.0 W and 3.3 +/- 1.0 degrees C at 1.4 W. Electronic micrographs revealed that there were no significant morphological changes, such as charring, melting, or fusion, in any group, although the specimens were found to be more irregular in the Er:YAG laser group. The application of Er:YAG and diode lasers at the utilized parameters did not induce high pulpal temperatures. Root surface irregularities were more pronounced after irradiation with an Er:YAG laser than with a diode laser.

The aim of this study was to evaluate in vitro, by scanning electron microscopy (SEM), the adhesion of blood components on root surfaces irradiated with Er:YAG (2.94 microm) and GaAlAs Diode (808 nm) lasers and the effects on the morphology of irradiated root surfaces. One hundred samples of human teeth were obtained. They were previously planed and scaled with manual instruments and divided into five groups of 20 samples each: G1 (control group) - absence of treatment; G2--Er:YAG laser (7.6 J/cm2); G3--Er:YAG laser (12.9 J/cm2); G4--Diode laser (90 J/cm2) and G5--Diode laser (108 J/cm2). After these treatments, 10 samples of each group received a blood tissue but the remaining 10 did not. After laboratory treatments, the samples were obtained by SEM, the photomicrographs were analysed by the score of adhesion of blood components and the results were statistically analysed (Kruskall-Wallis and Mann-Whitney test). In relation to the adhesion of blood components, the study showed no significant differences between the control group and the groups treated with Er:YAG laser (p = 0.9633 and 0.6229). Diode laser radiation was less effective than control group and Er:YAG laser radiation (p < 0.01). None of the proposed treatments increased the adhesion of blood components in a significant way when compared to the control group. Although the Er:YAG laser did not interfere in the adhesion of blood components, it caused more changes on the root surface, whereas the Diode laser inhibited the adhesion.

Purpose: Cavity disinfection is an essential procedure for success of Atraumatic restorative treatment. This study was designed to test the efficacy of diode laser and grape seeds extract as primary teeth cavity disinfectants. Methods: A total of 96 sound primary molars were divided into two groups according to the test performed (n=48); antimicrobial effect/ shear bond strength. Each group was subdivided into four subgroups according to cavity disinfectants: (n=12); group1: Control (no treatment), group 2: 2% chlorhexidine gluconates (CHX), group 3: diode laser, group 4: 5%w/v grape seed extract (GSE). Occlusal cavities were inoculated with the Streptococcus mutans (S.mutans) suspension and incubated under aerobic conditions. Dentine chips were collected and S.mutans colony forming units were counted. For shear bond strength, cylindrical glass ionomer specimens were bonded to dentine surface then loaded at tooth-restoration interface till debonding. Results: Diode laser exhibited the highest antibacterial effect. No difference was detected in mean values of shear bond strength in diode laser (5.88±1.28) and GSE (3.47±1.55) groups when compared to the negative control group (4.97±1.80). Conclusion: Diode laser system is preferred over GSE and CHX as a potent cavity disinfectant for primary teeth. GSE can be used as a natural alternative for CHX

Dentinal hypersensitivity is one of the most common problem, encountered in dental practice but has least predictable treatment outcome. The advent of lasers in dentistry has provided an additional therapeutic option for treating dentinal hypersensitivity. Although various lasers have been tried over a period of time to treat dentinal hypersensitivity, but still the doubt persist as to which laser leads to maximum dentinal tubular occlusion and is most suitable with minimal hazardous effects. To compare the effects of Nd: YAG, CO2 and 810-nm diode lasers on width of exposed dentinal tubule orifices and to evaluate the morphologic changes on dentinal surface of human tooth after laser irradiation by scanning electron microscope (SEM). Forty root specimens were obtained from ten freshly extracted human premolars, which were randomly divided into four groups of ten each. Group I: control group treated with only saline, Group II: Nd:YAG laser, Group III: CO2 laser and Group IV: 810-nm diode laser. The specimens were examined using SEM. After calculating mean tubular diameter for each group, the values were compared statistically using parametric one-way ANOVA test and Turkey's post hoc multiple comparison test. All the three lased groups showed a highly statistical significant result with p-value of <0.001 as compared to non-lased group. On intergroup comparison within the lased groups, all the three groups showed statistically significant difference in the reduction of dentinal tubular diameter (p-value < 0.001). Nd: YAG laser was found to be most effective, followed by the CO2 laser and 810-nm diode laser was found to be least effective. The morphologic changes like craters, cracks and charring effect of the dentine were seen maximum by the use of CO2 laser.

The Neodynium: Yttrium Aluminum Garnet (Nd: YAG) laser was one ofthe first lasers to allow tissue photoablation to be performed transendoscopically in the standing equine patient.1 It became very popular due to the fact that its irradiation can be applied through flexible fiber optic cables. Recently, a number of diode lasers have been marketed to the equine practitioner as replacements for the Nd: YAG laser, specifically the 810nm and 980nm diode lasers. Initially, both of these lasers produced a maximum of 20 watts total power output. Currently, higher power output versions being 50 or 60 watts are available to the practitioner. Producing a high power output means these lasers have the potential to be used in the non-contact configuration, as well as contact, when performing corrections of upper respiratory disorders ofthe horse. Penetration studies have been performed using lower power (20 watt) 810nm and 980nm diode laser which were compared to the depths and widths of penetration produced by the Nd: YAG laser.2,3 The purpose of this investigation was to evaluate the 60 watt 810nm diode lasers penetration delivering 200-600 joules on to equine respiratory tissue. Penetration parameters selected were width and depth of craters and were compared to the Nd: YAG laser set to deliver 200 joules of energy. This study determined that the 810nm diode lasers penetration parameter is close to that of the Nd: YAG laser. As the diode laser power output increased above 200 joules, it significantly penetrated respiratory tissue deeper than the Nd: YAG laser set at 200 joules output. Measurement of the crater depth created by the 810nm diode laser as its output power was increased at 100 joule increments was significantly deeper than the depth of crater formed by the previous power setting. Similarly, the diode laser's crater top and bottom width measurement, at 400 joules and greater, was significantly greater than or equal to that of the Nd: YAG lasers set to deliver 200 joules of energy. This investigation provided evidence that the 60 watt 810nm diode laser produces substantial penetration that can be applied not only in the contact mode successfully, but also in the non-contact mode providing the practitioner with a more versatile laser for transendoscopic application in the equine.

The objective of this study was to compare antibacterial and smear layer removal efficacy of the erbium:yttrium-aluminium-garnet (Er:YAG) laser irradiation by photon-induced photoacoustic streaming (PIPS), neodymium:yttrium-aluminium-garnet (Nd:YAG), and diode lasers and conventional irrigation agent in primary molar root canals. The selection, application, and activation of the irrigant are important factors affecting the success of the endodontic treatment. Distal root canals of human primary mandibular molar teeth used for antimicrobial efficacy evaluation were first inoculated with Enterococcus faecalis (n = 25). Smear layer removal efficacy was evaluated on the noninoculated specimens (n = 20). The root canals in the first treatment groups were irrigated with a conventional technique using 5% sodium hypochlorite (NaOCl). In the laser groups, the root canals were irradiated with either Nd:YAG (1064 nm) or diode lasers (940 nm) followed by NaOCl irrigation agent. In the fourth groups, the NaOCl irrigation agent was activated with an Er:YAG laser (2940 nm) by PIPS tip using nonablative settings. Antibacterial efficacy was determined by viable counts of E. faecalis after treatments. The treated root canals were examined by scanning electron microscopy to determine the smear layer removal efficacy of treatments. Statistically significant (p < 0.05) reductions in the number of E. faecalis were achieved in Nd:YAG and diode laser groups and Er:YAG laser by PIPS-activated irrigation groups compared to the NaOCl group. Er:YAG laser by PIPS-activated irrigation resulted in more cleaning of the root canal walls and a higher quantity of open tubules. These findings suggest that Er:YAG laser by PIPS-activated irrigation can be considered as an effective irrigant agitation technique in pediatric endodontics.

BackgroundWe aim to evaluate the presence of histological artefacts in the surgical margins of human oral fibro-epithelial hyperplasias excised with lasers of different wavelengths, and also electrosurgical scalpel and cold scalpel. Moreover, we aim to determine if some of these instruments could impair the normal histological diagnosis of these lesions.Material and MethodsWe included 130 consecutive surgical samples of 80 females and 50 males (mean age of 53.82±16.55) with a histological diagnosis of an oral benign fibrous-epithelial hyperplasias. The samples were categorized into 6 groups according to the type of instrument used: CO2 laser group, diode laser group, Er:YAG laser group, Nd:YAG laser group, electrosurgical scalpel group and cold scalpel group. Histological instrument-induced changes were microscopic evaluated and related with clinical and pathological variables.ResultsThe instrument with highest tissue damage extension (TDE) was the electrosurgical scalpel (1002.2µm±434.92), followed by diode laser (913.73 µm±322.45), Nd:YAG (899.83µm±327.75), CO2 laser (538.37µm±170.50), Er:YAG laser (166.47µm±123.85), and at last with fewer alterations the cold scalpel group (2.36µm±7.27) (P< 0.001). The most regular incision was observed in CO2 laser group, followed by Er:YAG laser, Nd:YAG laser, electrosurgical scalpel and diode laser group with the less regular incision using cold scalpel as comparison (P< 0.001). A correlation was found between the incision score and TDE (P< 0.001). Regarding histological diagnosis, no case showed any limitation of diagnosis related with the use of any instrument evaluated.ConclusionsOur results suggest that lasers can be used for the excision of oral benign fibrous-epithelial hyperplasias, without hispathological diagnosis limitations, as long as the physical properties of each laser are known and respected. Er:YAG laser have shown to be a laser with few tissue damage extension and with good incision regularity, been a possible instrument of choice for the surgical removal of these lesions. Key words:CO2 laser, diode laser, Er:YAG laser, Nd:YAG laser, oral mucosa.

The aim of this study was to evaluate the color and enamel structure changes after intracoronal bleaching with sodium perborate under neodymium:yttrium-aluminum-garnet (Nd:YAG) and diode laser irradiation. Although some studies investigated the efficacy of laser irradiation during intracoronal bleaching, no study has been conducted to investigate the changes in both color and enamel structure during intracoronal bleaching with laser irradiation. Thirty-six extracted mandibular incisors were used. The root canals were prepared and filled with AH Plus and gutta-percha. Baseline color values and Raman spectra were obtained from all samples. The samples were randomly divided into three groups as follows: group 1, intracoronal bleaching with sodium perborate plus NdYAG laser irradiation; group 2, intracoronal bleaching with sodium perborate plus diode laser irradiation; and group 3, intracoronal bleaching with sodium perborate without any laser irradiation. Following the bleaching procedures, the final baseline color values and Raman spectra were obtained. The baseline and final values were statistically analyzed. Statistical analyses were performed with SPSS 18.0 software using Anova and the Kruskal-Wallis test. There was a significant difference between the Nd:YAG laser and control groups (p<0.05). There was no significant difference between the diode laser group and the control group, or the diode laser group and the Nd:YAG laser group. There was no significant difference among all groups in terms of Raman relative intensity (RRI) and fluorescence intensity (FI) percentage values (p>0.05). Laser application, especially Nd:YAG laser irradiation, was able to increase the efficacy of intracoronal bleaching with sodium perborate. Laser irradiation significantly increased the bleaching efficacy without any changes in the enamel surface structure.

IntroductionResidual microorganisms may remain even after thorough mechanical cavity preparation, leading to secondary caries. Additionally, the smear layer generated during this process can impair the adhesion between composite resin and dentine and limit the penetration of disinfectants into dentinal tubules. This study aimed to compare the effects of 2% chlorhexidine (CHX), 980 nm diode laser, and Er:YAG laser as cavity disinfectants on dentine morphology, mineral content, and microleakage of composite restorations.Materials and MethodsForty extracted sound human primary molars were randomly assigned to four groups (n = 10): Group I (negative control, no disinfection), Group II (2% CHX application), Group III (980 nm diode laser, 1 W, continuous wave), and Group IV (Er:YAG laser, 1.2 W). Dentine morphology and restoration microleakage were examined via Scanning Electron Microscopy: (SEM), while mineral content was evaluated using Energy-Dispersive X-ray Spectroscopy (EDS).ResultsSEM analysis showed that CHX (Group II) left smear layer residues with narrowed tubules, while the diode laser (Group III) partially removed the smear layer. Er:YAG laser (Group IV) resulted in complete smear layer removal, wider tubules. EDS revealed significantly higher mineral content (Ca, P and Ca/P ratio)in Group IV compared to Groups II and group III (p < 0.001), with no significant difference between Groups II and III. Microleakage was highest in the control group and lowest in the Er:YAG group (p < 0.001).ConclusionThe Er:YAG laser showed enhanced outcomes in improving dentine morphology, increasing mineral content, and minimizing microleakage, making it the most effective disinfectant tested.