Journal of Lasers in Medical Sciences

Introduction: Laser therapy has been suggested as a method for caries-prevention, and ErCr:YSGG laser is increasingly used in dentistry. This study aimed to compare the efficacy of fluoride gel alone and in conjunction with Er,Cr:YSGG laser for remineralization of white spot lesions (WSLs) in primary teeth.
Methods: This study was conducted on 20 primary teeth with WSLs extracted for orthodontic reasons. Three sections were made of each tooth at the site of WSLs. The surface area of WSLs was measured under a stereomicroscope at ×25 magnification. Samples were assigned to 3 groups of control (group 1), exposure to 1.23% APF gel for 4 minutes (group 2) and Er,Cr:YSGG laser (0.5 W power, 20 Hz frequency, 60% water, 40% air, pulse duration of 5±1 seconds) plus fluoride (group 3). All samples were stored in artificial saliva for 10 days and then the surface area of the WSLs was measured again under a stereomicroscope. Data were analyzed using the Kruskal-Wallis, Mann-Whitney and Wilcoxon signed rank tests.
Results: The reduction in surface area of the WSLs was significantly different between the control and fluoride (P < 0.001) and also the control and laser plus fluoride groups (P < 0.001); the difference between fluoride and laser plus fluoride groups was not significant (P = 0.265). Comparison of the surface area of WSLs before and after the intervention showed no significant difference in group one (P = 0.737) while this difference in groups 2 (P < 0.001) and 3 (P < 0.001) was statistically significant.
Conclusion: The results showed that Er,Cr:YSGG laser irradiation plus 1.23% APF gel was not significantly different from the application of fluoride gel alone in enhancing the remineralization of WSLs.

Introduction: Successful root canal therapy depends on the complete elimination of micro-organisms such as Entroccocus faecalis, which is impossible to achieve with the traditional methods. Lasers are recently introduced as a new method to solve the problem. The present study is planned and performed to examining the antibacterial effect of Er: YAG laser.
Methods: Sixty extracted anterior primary teeth were prepared and sterilized. E. faecalis bacterium was cultured in canals. Samples were randomly divided into two groups. The first group was disinfected by NaOCl 5/25% and Er: YAG laser and the second group just by NaOCl 5/25%. Samples of canal contents were cultured and colony counts were calculated. The results were analyzed statistically by SPSS software and Mann Whitney test.
Results: There was no significant difference between colony counts in both groups (P = 0.142). But the number of colonies in the first group was lower than in the second group.
Conclusion: Although, Er: YAG laser cannot completely eliminate E. faecalis bacterium, its simultaneous use with NaOCl decreases E. faecalis.

Introduction: Early detection of secondary proximal caries is critical for the preservation of tooth vitality. This study sought to assess and compare the diagnostic accuracy of DIAGNOdent and digital radiography for detection of secondary proximal caries adjacent to composite restorations.
Methods: Sixty extracted molars including 30 teeth with carious lesions and 30 sound teeth were randomly selected. Class II cavities were prepared in all teeth and carious dentin was intentionally left in the gingival floor of cavities in 30 carious teeth. All cavities were restored with composite resin. The teeth were mounted in wax blocks (three teeth per block) and examined for caries using (DIAGNOdent kaVo Dental, Biberach, Germany). Digital radiographs using DIGORA photostimulable phosphor (PSP) plates (Soredex Corporation, Helsinki, Finland) were obtained from all teeth using the parallel technique and were evaluated by 4 observers. Repeated measure analysis of variance (ANOVA) was applied to calculate sensitivity and specificity values of the two diagnostic techniques. Receiver operating characteristic (ROC) curve was plotted for DIAGNOdent results and based on that, the cutoff points were determined.
Results: The sensitivity and specificity values at the cut-off point of 10.5 were 0.622 ± 0.038 and 0.822 ± 0.077 for DIAGNOdent and 0.591 ± 0.093 and 0.891 ± 0.083 for digital radiography, respectively. The area under the ROC curve was 0.7 for DIAGNOdent. Weighted kappa revealed moderate to almost perfect intra-observer agreement (0.46-0.99). Intraclass correlation coefficient (ICC) for DIAGNOdent was calculated to be 0.88.
Conclusion: No statistically significant difference was noted in diagnostic accuracy of DIAGNOdent and digital radiography for detection of secondary proximal caries adjacent to composite restorations. Thus, DIAGNOdent may be used as an adjunct diagnostic tool for detection of secondary proximal caries beneath composite restorations.

Background: Pemphigus vulgaris is a chronic blistering skin disease. Management of recalcitrant pemphigus ulcers is a great problem. Low Level Laser Therapy (LLLT) is known to supply direct biostimulative light energy to body cells. Objective: This study evaluates the efficacy of low power laser in the healing of pemphigus lesions.

Methods: Ten patients with pemphigus vulgaris were enrolled in the trial. The LED-LLLT system used was the Thor LED clusters (109, 69 or 19 diode) (ENGLAND) with 660 nm wave length in continuous wave (CW) and 30 MW energy. Both sides of the patients’ lesion were photographed prior to the study and in each laser therapy sessions.

Results: The pattern of changes in QWS patterns differed significantly over time between the two therapies (treatment × time interactions, p<.0001). When compared to the routine therapy, the laser therapy showed more decreases in mean QWS in all sessions in comparison with baseline.

Limitations: This is a pilot study.

Conclusion: Application of Low Level Laser simultaneously with conventional therapy could result in sensational healing of ulcers especially in patients who do not respond to conventional treatment or suffering from recalcitrant lesions.

Introduction: The aim of the present study was to evaluate and compare the effect of acid-etching and Er, Cr:YSGG laser treatment before the reattachment of incisal fragments in coronal fractures of permanent incisor teeth.
Methods: Sixty-six sound human maxillary incisors were randomly divided into 3 groups (n=22). Teeth were embedded in self-cure acrylic resins by leaving one-third of the crowns out, and uncomplicated crown fractures were obtained using an Instron testing device. The fragments were reattached using 3 different procedures and a hybrid resin composite (Z250): Group I: Acid etching + Prime & Bond NT; Group II: Er,Cr:YSGG + Prime & Bond NT; Group III: Er,Cr:YSGG + Acid etching + Prime & Bond NT. The percentages of shear bond strengths were determined by comparing fracture strengths of sound and reattached teeth for 3 groups. All data were analyzed statistically with Kruskal-Wallis H test.
Results: Mean fracture strengths of the reattached fragments were between 51.02% and 62.93% of that of the sound teeth in all groups. Group I had significantly higher percentages of shear bond strength values (P < 0.05) when compared to group II and group III. No significant difference (P > 0.05) was found between group II and group III.
Conclusion: The findings of the present study show that Er,Cr:YSGG laser irradiation prior to the reattachment of incisal fragments has a negative effect on fracture strength.

Introduction: Successful repair of composite restorations depends on a strong bond between the old composite and the repair composite. This study sought to assess the repair shear bond strength of aged silorane-based composite following surface treatment with Nd:YAG, Er,Cr:YSGG and CO2 lasers.
Methods: Seventy-six Filtek silorane composite cylinders were fabricated and aged by 2 months of water storage at 37°C. The samples were randomly divided into 4 groups (n = 19) of no surface treatment (group 1) and surface treatment with Er,Cr:YSGG (group 2), Nd:YAG (group 3) and CO2 (group 4) lasers. The repair composite was applied and the shear bond strength was measured. The data were analyzed using one-way analysis of variance (ANOVA) and Tukey post-hoc test. Prior to the application of the repair composite, 2 samples were randomly selected from each group and topographic changes on their surfaces following laser irradiation were studied using a scanning electron microscope (SEM). Seventeen other samples were also fabricated for assessment of cohesive strength of composite.
Results: The highest and the lowest mean bond strength values were 8.99 MPa and 6.69 MPa for Er,Cr:YSGG and control groups, respectively. The difference in the repair bond strength was statistically significant between the Er,Cr:YSGG and other groups. Bond strength of the control, Nd:YAG and CO2 groups was not significantly different. The SEM micrographs revealed variable degrees of ablation and surface roughness in laser-treated groups.
Conclusion: Surface treatment with Er,Cr:YSGG laser significantly increase the repair bond strength of aged silorane-based composite resin.

Introduction: This study sought to assess the effect of bleaching combined with irradiation of 810 nm and 980 nm diode laser on microhardness of 2 commonly used self-cure and light-cure glass ionomer cements (GICs) in comparison with conventional bleaching (without laser). 

Methods: In this in vitro, experimental study, 60 samples were fabricated of A2 shade of Fuji IX and Fuji II LC GICs (n = 30) and each group was divided into 3 subgroups (n = 10). The first subgroups were subjected to bleaching with Opalescence Xtra Boost plus 980 nm diode laser irradiation. The second subgroups were subjected to bleaching with Opalescence Boost plus 810 nm diode laser irradiation and the third subgroups were subjected to bleaching with Opalescence Xtra Boost without laser. Microhardness was measured at baseline and after the intervention using Vickers hardness tester. The data were analyzed using two-way analysis of variance (ANOVA) (P < 0.05).

Results: Microhardness decreased in all subgroups after the intervention (P < 0.001) irrespective of the type of GIC (P = 0.201) or surface treatment (P = 0.570). The baseline microhardness of the three subgroups within each group of GIC was not significantly different (P = 0.456), but the baseline microhardness of conventional GIC was significantly higher than that of resin modified GIC (P = 0.004).

Conclusion: Bleaching with/without laser irradiation decreases the microhardness of GICs. The baseline microhardness of conventional GIC is higher than that of resin modified GIC.

Introduction: Laser irradiation has been suggested as an adjunct to traditional methods of canal preparation but few studies are available on the antibacterial effect of diode laser in pulpectomy of primary teeth. The purpose of the present study is to investigate the antibacterial effect of diode laser in pulpectomy of primary teeth, in addition to define the optimal and harmless diode lasing conditions in the root canal.
Methods: A total of 125 single rooted primary teeth were selected. After traditional canal cleaning, they were divided in 2 groups. Sixty-five specimens after culturing of Enterococcus faecalis into the canals, were divided in 3 groups: (1) traditional canal cleaning with 0.5% NaOCl irrigation, (2) method of group 1+ 1.5 W diode laser (980 nm, pulse), (3) without treatment (5 specimens). Then the specimens were cultured and after colony counting under light microscope, were statistically analyzed by Kruskal-Wallis and Mann-Whitney tests. For 60 specimens, temperature rise of apical and cervical parts of the external root surface were measured using 2 thermocouple type K, when radiating a 1.5 W diode laser into the canal.
Results: In the first experiment, the diode laser group showed tmost reduction in bacterial count. And in the second experiment, the mean temperature rise of external root surface was less than the threshold of periodontal ligament (PDL) damage.
Conclusion: Diode laser with a power output of 1.5 W, is effective in reduction of E. faecalis bacterial count without damaging periodontal structures.

Case Presentation: This study aimed to report a case of medication related osteonecrosis of the jaw (MRONJ) of a 65-year-old female patient referred to the Oral and Maxillofacial Surgery team from Araçatuba Dental School, complaining about mobility of a previously dental implant placed on the posterior maxillary region. Clinical examination revealed an extensive necrosis area around the implant region. The patient reported bisphosphonate therapy with sodium alendronate for prevention of osteoporosis 5 years ago. A diagnosis of MRONJ was reached and the treatment decided was to remove the dental implant damaged and use the lower-level laser therapy (LLLT) associated with antibiotic therapy with clindamycin 300 mg and mouth rinses with chlorhexidine 0.12%.
Conclusion: Six months after the treatment with LLLT a complete healing of the affected area was observed and 12 months after treatment the patient was rehabilitated with fixed dental prosthesis and showed excellent tissue healing of the necrosis areas. It was concluded that the use of LLLT showed to be a good option in the treatment of MRONJ.