Photobiomodulation for the management of xerostomia and oral mucositis in patients with cancer: a randomized clinical trial.

To evaluate the applicability of photobiomodulation therapy (PBM-T) in the management of xerostomia and OM. Fifty-three patients with head and neck squamous cell carcinoma were randomized into two groups: Sham and PBM-T. The Sham group received artificial saliva and laser simulation, while the PBM-T group received artificial saliva and PBM-T. Xerostomia-related quality of life (QoL), the presence or absence of OM lesions, the decayed-missing-filled teeth (DMFT) index, and periodontal charts were evaluated. The results of the QoL questionnaire, DMFT index, and periodontal chart were analyzed with the Kruskal-Wallis test, followed by the Student-Newman-Keuls test, while OM findings were compared using the Mann-Whitney test. QoL scores significantly increased in the Sham group (p < 0.0001), denoting more severe xerostomia symptoms (p = 0.0074), and decreased in the PBM-T group, indicating no or very mild xerostomia. Higher grades of OM were found in the Sham group than the PBM-T group (p = 0.0001). There was no significant difference in DMFT index or periodontal charts between the groups (p > 0.05). PBM-T improved QoL in patients with head and neck cancer treated with radiotherapy, whether as radiation alone or as an adjunct to chemotherapy and surgery.

Dog-assisted therapy for control of anxiety in pediatric dentistry.

Anxiety is common in pediatric dental care, and affects the behavioral management of children. Animal-assisted therapy (AAT) has been shown to improve children's behavior. However, few studies have applied this technique in dentistry. The aim of the present study was to evaluate the applicability of dog-assisted therapy to control anxiety during pediatric dental treatment. Twenty children were selected from the Pediatric Dentistry Clinic of the Pontifical Catholic University of Campinas (PUC-Campinas), Brazil. Participants were divided into two groups: Control (n = 11; visits = 16), in which children were conditioned by methods routinely used in the clinic; and AAT (n = 9; visits = 23), in which children had contact with a dog therapist first at the reception desk and then again inside the office. The dog therapist stayed beside the dental chair with the child throughout the procedures. Corah's Dental Anxiety Scale (CS) and heart rate (HR) were used for evaluation of child anxiety. The results were tested for normality of distribution with the Shapiro-Wilk method, and subsequently analyzed in BioEstat 5.0. HR results were compared by Analysis of Variance (ANOVA) with Tukey's test, and CS scores, with the Wilcoxon test. There was a significant reduction in HR in the AAT group (p = 0.0069). In the Control group, HR did not change before, during, or after treatment (p = 0.6052). Controls showed a significant increase in anxiety measured by CS before and after treatment (p = 0.0455). In the AAT group, there was no change in CS scores before and after treatment (p = 0.3739). AAT could be an alternative to reduce anxiety during pediatric dental care.

Effect of cetrimide 2% with and without photodynamic therapy to reduce Streptococcus mutans burden in dentinal carious lesions.

To evaluate the use of cetrimide alone and combined with photodynamic therapy to reduce S. mutans burden in carious lesions. Sixty permanent third molars were sectioned and the coronal dentin exposed. A cariogenic challenge was performed using brain-heart infusion (BHI) medium supplemented and S. mutans ATCC 25175. Specimens were incubated in anaerobic jars at 37 °C for 15 days, with BHI renewed every 24 h. After 15 days, specimens were randomly divided into six groups (n = 10): C, control (no treatment); CHX, application of chlorhexidine 2%; CT, application of cetrimide 2%; CT+aPDT, application of cetrimide 2% followed by methylene blue dye and aPDT (antimicrobial photodynamic therapy: wavelength 660 nm, energy 4J, power 100 mW, spot size 0.0028 cm2, energy density 142 J/cm2 for 40 s); ES+aPDT, application of experimental solution (methylene blue dye with cetrimide) and aPDT; and aPDT alone. Carious tissue from each specimen was collected before and after the applications. Five decimal dilutions were performed, and the resulting solution was seeded in mitis-salivarius-bacitracin agar. Plates were incubated in anaerobic jars at 37 °C for 48 h. Analysis of variance (ANOVA) with post hoc Tukey's test was used to compare total S. mutans counts. Significant reductions in S. mutans were observed after application of CT+aPDT (0.30 (0.97), p < 0.0001) and ES+aPDT (0.52 (1.13), p < 0.0001). Cetrimide 2% with methylene blue dye, applied consecutively or as a mixture, can be used as a photosensitizing agent for aPDT to reduce S. mutans burden in dentinal caries.

Dental acid etchant as a sensitizing agent in photodynamic therapy to reduce S. mutans in dentinal carious lesions.

The study aims to assess the utility of dental acid etchant containing 37% phosphoric acid and methylene blue dye (DAE) as a sensitizing agent for photodynamic therapy (PDT) to reduce Streptococci mutans in dentinal caries. Forty-five permanent third molars were sectioned and the coronal dentin exposed. A cariogenic challenge was performed using brain-heart infusion (BHI) supplemented with 0.5% yeast extract, 1% glucose, 1% sucrose, and S. mutans ATCC 25175 standardized to 0.5 McFarland turbidity. Specimens were incubated in anaerobic jars at 37 °C for 15 days. During this period, BHI broth was renewed every 24 h. After 15 days, specimens were randomly divided into three groups (n = 15): DAE, application of dental acid etchant containing 37% phosphoric acid and methylene blue dye for 15 s; LLL, application of low-level laser (wavelength 660 nm, energy 4 J/cm2, power 5 W) for 15 s; and PDT, application of DAE for 15 s followed by LLL irradiation (660 nm, 4 J/cm2, 5 W). Carious tissue from each specimen was collected before and after the applications. Five decimal dilutions were performed and the resulting solution was seeded in mitis-salivarius-bacitracin agar. Plates were incubated in anaerobic jars at 37 °C for 48 h. Analysis of variance (ANOVA) with post hoc Tukey's test was used to compare total S. mutans counts. Significant reductions in S. mutans were observed after DAE application (40.70%, p < 0.0001), LLL (12.35%, p = 0.0036), and PDT (55.22%, p < 0.0001). Dental acid etchant containing 37% phosphoric acid and methylene blue dye can be used as a photosensitizing agent for PDT to reduce S. mutans burden in dentinal caries.

Effectiveness of casein phosphopeptide-amorphous calcium phosphate and lysozyme, lactoferrin, and lactoperoxidase in reducing Streptococcus mutans counts in dentinal caries.

This study compared the capacity of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) to that of a combination of lysozyme, lactoferrin, and lactoperoxidase (LLL) in root canal disinfectant for reducing the Streptococcus mutans counts from dentinal caries. Forty human permanent third molars were selected, and flat dentin surfaces were created. Carious lesions were induced using a microbiological model. The specimens were randomly divided into 2 groups (n = 20) according to the type of agent used: group 1, CPP-ACP; group 2, LLL. The S mutans counts were performed before application and after the first, second, and third applications of the agents. The duration of each application was 3 minutes. Carious dentin specimens were homogenized, diluted, and seeded onto mitis salivarius-bacitracin plates for viable counts of S mutans. Results showed that there was no significant reduction in the number of S mutans in group 1 after the applications of CPP-ACP (P > 0.05). In group 2, a significant reduction of S mutans was observed after the third application of LLL (P < 0.01). These results indicate that 3 applications of LLL enzymes can be used to reduce the number of S mutans in dentinal caries lesions.

Effect of Endodontic Retreatment on Push-out Bond Strength and Quality of Fiber Postbonding Interface of Resin Cements.

AIM: The aim of this study is to evaluate the impact of endodontic retreatment on push-out bond strength and dentin interface of two resin cements used for fiber postcementation during endodontic retreatment. MATERIALS AND METHODS: The root canals of 40 extracted human canines were prepared, obturated and divided into four groups (n = 10). Gutta-percha was partially removed and fiber posts were immediately cemented in groups 1 and 2 using Panavia F with ED Primer and RelyX™ U200, respectively. In groups 3 and 4, the root canal access was sealed with temporary restorative cement, specimens were stored for 30 days, endodontically retreated, and fiber posts were cemented using the resin cements applied to groups 1 and 2, respectively. Push-out tests and scanning electron microscopy analyses of different areas were performed. Data from push-out bond strengths were analyzed by one-way analysis of variance and Tukey's tests. RESULTS: Higher bond strength values were detected in the apical third for group 1 than group 3 (p < 0.05). No differences were observed in other comparisons between the same third of different groups (p > 0.05). Comparisons between different thirds in the same group revealed a higher bond strength in the apical third for group 1. Scanning electron microscopy showed formation of hybrid layer and extensive resin tags in group 1. No hybrid layer was observed in groups 2 and 4. CONCLUSION: Endodontic retreatment had adverse effects on the push-out bond strength and dentinal interface of Panavia F with ED Primer when used for fiber postcementation specifically in the apical third, but not on RelyX™ U200. CLINICAL SIGNIFICANCE: A significant interaction was detected between endodontic retreatment and resin cement, which indicated that endodontic retreatment might adversely affect the push-out bond strength and dentinal interface of Panavia F with ED Primer when used for fiber postcementation specifically in the apical third.

Comparative Analysis of Protaper and Waveone Systems to Reduce Enterococcus Faecalis from Root Canal System in Primary Molars--An in Vitro Study.

OBJECTIVE: To assess, in vitro, the ability of the ProTaper(™) and WaveOne(™) systems to reduce Enterococcus faecalis contamination in primary molars. STUDY DESIGN: Sixty roots of primary molars were contaminated with E. faecalis. Roots were randomly allocated to one of four groups (n=20): ProTaper(™), WaveOne(™), control A, or control B. The files used were S1 and S2/F1 and F2 (ProTaper(™) system) and 25.08 (WaveOne(™) system). In control group A, the root canal was left uninstrumented, whereas in control group B, the root canal was irrigated with NaCl 0.9%. E. faecalis was sampled from the root canal system before and after instrumentation and the Wilcoxon test and Mann-Whitney U were used. RESULTS: There were no differences in E. faecalis counts between pre-instrumentation counts in the ProTaper™ and WaveOne(™) (p>0.05). The ProTaper(™) system led to an 89.36% reduction in E. faecalis burden, versus 78.10% with the WaveOne(™) system (p>0.05). Instrumentation time was shorter with WaveOne(™) (p<0.0001). CONCLUSIONS: The ProTaper(™) and WaveOne™ systems were equally effective in reducing Enterococcus faecalis in primary molars. The WaveOne(™) system was associated with shorter instrumentation time.

Influence of instrumentation techniques and irrigating solutions on bond strength of glass fiber posts to root dentin.

This study sought to evaluate how instrumentation techniques and irrigating solutions affected the bond strength of glass fiber posts. For this study, 80 human maxillary central incisors were selected. Endodontic access was obtained, root canal length was measured, and the coronal third was prepared using Gates-Glidden drills. The specimens were embedded in acrylic resin and randomly assigned to 8 groups (n = 10): manual instrumentation only (Group 1), rotary instrumentation only (Group 2), irrigation with 2.5% sodium hypochlorite (NaOCl) (Group 3), irrigation with 2% chlorhexidine (CHX) (Group 4), manual instrumentation and irrigation with 2.5% NaOCl (Group 5), manual instrumentation and irrigation with 2% CHX (Group 6), rotary instrumentation and irrigation with 2.5% NaOCl (Group 7), and rotary instrumentation and irrigation with 2% CHX (Group 8). Specimens in Groups 5-8 also received a 1 minute final rinse with ethylenediaminetetraacetic acid. Canals were filled and the specimens stored for 30 days in distilled water. The restoration material was removed down to the apical 4 mm of the root canal. The glass fiber posts were luted with resin cement and stored for 24 hours at 37°C. Specimens were subjected to a tensile strength test at a constant speed of 1.0 mm/minute and a load of 2,000 kgf. The results were analyzed by analysis of variance and Tukey's test. Irrigation with 2.5% NaOCl reduced the bond strength of fiber posts significantly (P < 0.01), while CHX showed no effect (P > 0.05). It was concluded that irrigation with 2.5% NaOCl has a negative effect on micromechanical retention of glass fiber posts, whether manual or rotary instrumentation is used.

Influence of metalloproteinases on dentin hybridization of one-bottle or self-etch dental bonding systems.

AIM: To assess the influence of dentin substrate and chlorhexidine on the marginal seal of composite resin restorations. MATERIALS AND METHODS: The sample comprised 20 third molars. Four cavities were drilled in the dentin sur face, followed by sealing and restoration of sound dentin (n = 10) or carious dentin (n = 10). In the control group, cavities were immediately restored as follows: G1: one-bottle bonding agent (OB) + composite resin (CR); G2: chlorhexidine 2.0% (CLX) + OB + CR; G3: self-etch bonding agent (SE) + CR; G4: CLX + SE + CR. In the experimental group (carious dentin), carious lesions were induced with S. mutans and cavities were restored as in the control group. Five specimens from each group (sound and carious) were stored in brain-heart infusion (BHI) medium for 6 months. All specimens were submerged in methylene blue 0.5% to test for microleakage. The Kruskal-Wallis and Student-Newman-Keuls tests were used to assess results. RESULTS: On immediate assessment, there were no significant between-group differences in the sound dentin group, whereas in carious dentin, there was less leakage when OB and CLX were used. At 6 months, there was less leakage in the sound dentin group when OB and CLX were used; there were no between-group differences in carious dentin. Comparison of immediate and 6-month assessments showed a significant increase in leakage at 6 months when sound dentin was treated with SE and CLX and when carious dentin was treated with OB and CLX. CONCLUSION: To ensure better dentin hybridization and preservation of the organic constituents of the dentin matrix, the properties of chlorhexidine digluconate and the components of the resin matrix must be taken into account. CLINICAL SIGNIFICANCE: Metalloproteinases influence degradation of the hybrid layer in composite resin restorations, regardless of whether the bonding system used is one-bottle or self-etching.

Photobiomodulation in the Treatment of Dysgeusia in Patients with Long COVID: A Single-Blind, Randomized Controlled Trial.

Objective: The aim of this study is to evaluate local and systemic photobiomodulation (PBM) in patients with COVID-19-related dysgeusia, with the expectation of improving taste dysfunction. Background: PBM has garnered attention as a potential therapy in long COVID, a condition characterized by many persistent symptoms following the acute phase of COVID-19. Among these symptoms, dysgeusia, or altered taste perception, can significantly affect patients' quality of life. Emerging research suggests that PBM may hold promise in ameliorating dysgeusia by modulating cellular processes and reducing inflammation. Further clinical studies and randomized controlled trials are essential to establish the efficacy and safety of PBM for the treatment of dysgeusia in long COVID, but initial evidence suggests that this noninvasive modality may offer a novel avenue for symptom management. Methods: Seventy patients experiencing dysgeusia were randomly assigned to receive active local and systemic PBM (n = 34) or simulated PBM (n = 36). Low-power laser (red wavelength) was used at 18 spots on the lateral borders of the tongue (3 J per spot), salivary glands (parotid, sublingual, and submandibular glands-3 J per spot), and over the carotid artery for 10 min (60 J). Alongside laser therapy, all patients in both groups received weekly olfactory therapy for up to 8 weeks. Results: Dysgeusia improved in both groups. At weeks 7 and 8, improvement scores were significantly higher in the PBM group than in the sham group (p = 0.048). Conclusions: Combined local and systemic PBM, as applied in this study, proved effective and could serve as a viable treatment option for alleviating dysgeusia in long-COVID patients. Clinical Trial Registration: RBR-2mfbkkk.

Influence of Passive Ultrasonic Irrigation of the Photosensitizer Used in Photodynamic Therapy on Microbial Reduction in the Root Canal System: An in Vitro Study.

Introduction: The success of endodontic treatment is based on microbial reduction promoted by the interaction of chemical and mechanical procedures. Photodynamic therapy (PDT) is used as an adjunct to conventional treatment, with significant microbial reduction. This study aimed to evaluate the influence of passive ultrasonic irrigation (PUI) of the photosensitizer (PS) used in PDT on microbial reduction in the root canal system. Materials and Methods: Forty-five mesiobuccal root canals from extracted human mandibular molars that were inoculated with standard strains of Enterococcus faecalis, Candida albicans, and Streptococcus mutans for 21 days were selected. The root canals were prepared using the ProTaper Next system and randomly divided into 3 groups (n=15): 1) PDT: PDT alone; 2) PUI+PDT: PUI followed by PDT; and 3) PUI/PS+PDT: PUI of the PS followed by PDT. Microbiological samples were collected from the canals before and after using the protocols described above. The data were analyzed by analysis of variance (Tukey's test) at a significance level of 5%. Results: Microbial counts before PDT, PUI+PDT, and PUI/PS+PDT did not differ significantly (P>0.05), showing methodological standardization in the microbial contamination of the root canal system. There was a significant reduction in microbial counts after PDT (61.05%), PUI+PDT (65.04%), and PUI/PS+PDT (68.58%) (P<0.01), but with no statistically significant difference between the three groups (P>0.05). Conclusion: Based on the present findings, it was concluded that the combination of PUI with PDT or PS activation did not influence microbial reduction achieved by PDT alone.

Photobiomodulation for Pain Relief After Third Molar Extraction: A Randomized Double-Blind Split-Mouth Clinical Trial.

Objective: To evaluate the local and systemic application of photobiomodulation (PBM) to reduce pain after third molar extraction. Background: PBM has been applied locally to reduce pain after third molar extraction, but there are no published studies evaluating its systemic application for this purpose. Methods: Thirty patients with two erupted third molars indicated for extraction were included in this split-mouth clinical trial. Extractions were performed 3 weeks apart in each patient, with one extraction socket being randomly assigned to local and systemic PBM (PBM group) and the other to no PBM (control group). Postoperative analgesia consisted of oral acetaminophen for 3 days. Outcomes included pain (visual analog scale), swelling, and quality of life (14-item Oral Health Impact Profile) assessed before and immediately, 24 h, 48 h, and 7 days after extraction. Results were analyzed by Kruskal-Wallis test, followed by Student-Newman-Keuls test. Results: In the control group, pain increased significantly at 24 and 48 h after extraction (p = 0.0000), decreasing after 7 days (before: 0.36; immediately after: 1.06; 24 h: 4.26; 48 h: 2.53; 7 days: 0.36). In the PBM group, patients reported no pain at all time points, indicating effectiveness of local and systemic PBM in relieving pain after third molar extraction (p = 0.2151) (before: 0.30; immediately after: 0.36; 24 h: 0.86; 48 h: 0.30; 7 days: 0.03). PBM also had a modulatory effect on the inflammatory process and improved comfort after extraction. Conclusions: Combined local and systemic PBM can be useful for pain relief, swelling control, and quality-of-life improvement in patients undergoing third molar extraction.

Evaluation of the apical sealing of an eggshell hydroxyapatite-based sealer.

Background: The success of endodontic treatment can be influenced by the type of endodontic sealer used, as certain sealers may be prone to apical microleakage, leading to treatment failure. The limitations of currently available sealers necessitate the development of new materials to improve the success rate of endodontic treatment. Therefore, the objective of this study was to assess the apical microleakage of newly developed hydroxyapatite-based endodontic sealers, including one derived from eggshells, and compare them with other commercially available sealers. Material and Methods: Eighty-five extracted human upper anterior teeth were selected for this study. The teeth were divided into 5 experimental groups and 2 control groups. The experimental groups were designated as follows: (1) HPSINT - obturated with gutta-percha cone and synthetic hydroxyapatite-based sealer, (2) BIOC - obturated with gutta-percha cone and Bio C-Sealer sealer, (3) AHPLUS-BC - obturated with gutta-percha cone and AHPLUS Bioceramic sealer, (4) AHP - obturated with gutta-percha cone and AHPLUS sealer, and (5) HPO - obturated with gutta-percha cone and sealer based on hydroxyapatite extracted from eggshells. Additionally, there were positive and negative control groups consisting of instrumented teeth filled with gutta-percha cones without any sealer and instrumented teeth without any filling, respectively. Methylene blue dye penetration was used to assess apical microleakage. Descriptive statistical analysis and Shapiro-Wilk normality test were applied to the observed results. As the samples followed a normal distribution, the ANOVA test was applied. Results: The control groups confirmed the validity of the experimental method, while the experimental groups showed varying degrees of dye penetration. The group obturated with Bio C-Sealer exhibited the highest mean apical microleakage, while AHPLUS Bioceramic sealer demonstrated lower mean than AHPLUS sealer and sealer based on hydroxyapatite extracted from eggshells (p<0.05). Finally, there was no difference between the synthetic hydroxyapatite-based sealer and AHPLUS Bioceramic sealer, AHPLUS sealer and sealer based on hydroxyapatite extracted from eggshells (p>0.05). No significant difference was observed between the hydroxyapatite-based sealers and the AHPLUS-BC sealer. Conclusions: The results of this study suggest that the newly developed hydroxyapatite-based endodontic sealers, including the one derived from eggshells, may have a lower risk of apical microleakage compared to other commercially available sealers. These findings highlight the potential of hydroxyapatite-based sealers to improve the success rate of endodontic treatment. Further research and clinical studies are warranted to validate these results and explore the long-term effects of these novel sealers. Key words:Endodontic treatment, apical microleakage, endodontic sealer, hydroxyapatite, eggshell-derived sealer.

In vitro evaluation of EDTA combined with photodynamic therapy to reduce Streptococcus mutans in carious dentin.

BACKGROUND: This in vitro study aimed to evaluate the use of EDTA combined with photodynamic therapy to reduce Streptococcus mutans in carious dentin. METHODS: Sixty third molars were sectioned to obtain flat dentin surfaces. All specimens were waterproofed, except for the coronal dentin, and subjected to cariogenic challenge in brain-heart infusion (BHI) broth supplemented with 0.5% yeast extract, 1% glucose, 1% sucrose, and standard strain of S. mutans (ATCC 25175). The specimens were divided into 6 groups (n = 10 each): (1) control - caries collection; (2) EDTA - 17% EDTA was actively applied with a microbrush for 1 min; (3) aPDT - antimicrobial photodynamic therapy with 0.01% methylene blue photosensitizer (wavelength of 660 nm, energy of 4 J, power of 100 mW, spot size of 0.028 cm2, energy density of 142 J/cm2 for 40 s); (4) EDTA+aPDT - 17% EDTA actively applied for 1 min plus aPDT; (5) (EDTA+PT) + L - application of EDTA compounded with photosensitizer plus laser irradiation; and (6) PT - photosensitizer alone. Collection of caries was performed after the different cavity disinfection protocols. Aliquots from each dilution were seeded for colony-forming unit (CFU) counts. The results were log10-transformed and analyzed by the Kruskal-Wallis test (Student-Newman-Keuls). RESULTS: There was a significant reduction in S. mutans after aPDT (p<0.05), EDTA+aPDT (p<0.001), and (EDTA+PT) + L (p<0.001). The percentage of microbial reduction in ascending order was as follows: EDTA: 1.65%; PT: 15.51%; aPDT: 38.28%; EDTA+aPDT: 75.24%; and (EDTA+PT) + L: 97.35%. CONCLUSION: Application of 17% EDTA prior to photosensitization or compounded with a photosensitizer increased the antimicrobial effect of aPDT on S. mutans in carious dentin.

Clinical Evaluation of Intravascular Blood Irradiation with Laser, Photobiomodulation, and Photodynamic Therapy in Cancer Patients with Mucositis.

Objective: To assess the clinical application of intravascular laser irradiation of blood (ILIB), photodynamic therapy (PDT), and photobiomodulation therapy (PBM-T) in mucositis in cancer patients. Background: PBM-T and PDT are used for the management of oral mucositis (OM) and there are no studies associating intravascular laser irradiation of blood (ILIB) for this purpose. Materials and methods: Thirty-six patients were allocated by convenience into three groups according to the established therapy: PDT+PBM-T (n = 10); PDT+PBM-T+ILIB (n = 10), and ILIB (n = 16). PDT was performed with the photosensitizer curcumin and irradiation of the oral cavity with blue light-emitting diode (LED) (power 1200 mW and wavelength 468 nm). PBM-T was performed using low-intensity laser (power 100 mW, wavelength 660 nm, and spot energy 1 J) at 26 points of the oral cavity. ILIB was applied with a bracelet on the radial artery using the low-intensity laser (100 mW of power, 660 nm wavelength, and 30 J of total energy). All therapies were performed weekly for 5 weeks. The results of the OM degrees were analyzed using the Wilcoxon test. Results: There was a significant reduction in the degrees of OM after treatment with PDT+PBM-T (p = 0.0117), PDT+PBM-T+ILIB (p = 0.0277), and ILIB (p = 0.0277). Conclusions: It was concluded that ILIB, PDT, and PBM-T reduced the severity of mucositis and prevented its onset. Clinical Trial Registration number: RBR-54XS25.

Evaluation of the furcation area permeability of deciduous molars treated by neodymium:yttrium-aluminum-garnet laser or adhesive.

The purpose of this in vitro study was to compare the effects of a self-etch adhesive system and neodymium:yttrium-aluminum-garnet (Nd:YAG) laser application on the dentinal permeability of the furcation area of primary molars. After endodontic access, 39 extracted human deciduous molars were divided into three groups: control group (CG), no treatment; adhesive group (AG), self-etching adhesive was applied to the furcation area; laser group (LG), specimens were irradiated with Nd:YAG laser. To evaluate dentin permeability of the furcation area, we immersed the specimens in 0.5 % methylene blue dye for 4 h. Then, they were longitudinally sectioned into two halves and photographed. The images were analyzed by two qualified evaluators using TpsDig software to calculate the percentage of the dye penetration area in comparison with the total furcation area. Additional analyses by scanning electron microscopy (SEM) were performed. The analysis of variance (ANOVA), complemented by Student's t-test, showed that mean dye penetration in the LG was statistically significant lower than that in all the other groups (P < 0.05). The SEM analysis showed mostly dentinal tubules obliterated by smear layer in the CG; in the AG the smear layer was modified by the adhesive, and, in the LG, melted surfaces were observed. It can be concluded that the Nd:YAG laser was capable of reducing the dentinal permeability of the furcation area of deciduous molars.

Capacity of photodynamic therapy for microbial reduction in periodontal pockets.

Practitioners are not successful in implemented treatments due to the great difficulty in completely removing bacterial deposits and their endotoxins. This study aimed to evaluate the capacity of photodynamic therapy to reduce the numbers of viable bacteria in periodontal pockets. Microbiological samples were collected before and after scaling and after photodynamic therapy. Photodynamic therapy was performed through the insertion of the photosensitizer toluidine blue and Endo PTC into the pocket for 3 min, followed by photosensitization with low-intensity diode of 4 J/cm(2). The results (log(10)) were submitted to a descriptive analysis and a t-test. A reduction of 81.24% in the numbers of bacteria after scaling was observed, as well as 95.90% after photodynamic therapy (P < 0.01). Photodynamic therapy is indicated as an adjuvant treatment to reduce the numbers of viable bacteria in periodontal diseases.

Repairing collagen in dentin carious lesions. Influence of sealing the material: a morphometric study.

OBJECTIVE: The aim of the present work was to morphometrically evaluate collagen in carious lesions sealed with calcium hydroxide, adhesive systems, glass ionomer cement, and an antibacterial cement. STUDY DESIGN: Samples of infected and affected dentin were stained with Sirius Red (SR). The areas intensively stained with SR were delimited, and the percentage of these areas was measured by blind calibrated examiners. The mean results were subjected to the Kruskal-Wallis test. RESULTS: The affected dentin sealed with Ca(OH)2 showed a better organization of the collagen in relation to the adhesive systems Prime & Bond (p = .0159) and Adhese (p < 0.0001). The affected dentin sealed with Prime & Bond promoted better increase of organized collagen areas in relation to Adhese (p = 0.0004). The infected dentin sealed with glass ionomer cement (p = 0.0018) or antibacterial cement (p = 0.0004) brought a significant increase in the organized collagen areas. CONCLUSIONS: Ca(OH)2 is indicated to seal affected dentin and glass ionomer cement and antibacterial cement may be used for treatment of infected dentin. The addition of antibiotics did not influence the restoration of the infected dentin.

Polyacrylic Acid with Methylene Blue Dye as a Sensitizing Agent for Photodynamic Therapy to Reduce Streptococcus mutans in Dentinal Caries.

Objective: To evaluate 11.5% polyacrylic acid (PA) containing 0.3% methylene blue (MB) dye as a photosensitizer for photodynamic therapy (PDT) of carious dentin. Methods: One hundred twenty molars were selected and the dentin was exposed for cariogenic challenge, where the molars were placed in brain heart infusion medium containing a standard strain of Streptococcus mutans (ATCC). Samples were randomly divided into eight groups (n = 15): S: saline, PA, MB: MB 0.3%, PA+MB: PA containing 0.3% MB + LLL: irradiation with low-level laser, PDT (MB): MB 0.3% + laser, PDT (PA): PA + laser, and PDT (PA+MB): PA containing 0.3% MB + laser. Carious dentin was collected before and after exposure to S. mutans. All samples of carious dentin were homogenized, diluted, and seeded in mitis salivarius bacitracin medium, and the cultures were incubated at 37°C for 15 days in anaerobic jars. The Wilcoxon test was used for analysis. Results: The percent microbial reduction achieved with each treatment was as follows: PDT (MB), 53.62%; PDT (PA+MB), 50.47%; PDT (PA), 46.73%; PA, 38.51%; MB, 19.75%; PA+MB, 17.18%; LLL, 12.83%; S, 5.99%. The greatest reductions in S. mutans growth occurred with PDT (MB), PDT (PA+MB), and PDT (PA) when compared to the S group (p = 0.0002, 0.0023, and 0.0232, respectively). Conclusions: PA containing 0.3% MB can be used as a photosensitizer for PDT to reduce S. mutans burden in carious dentin.

Influence of the Chelating Solutions in the Resistance of Glass Fiber Posts to the Root Dentin.

OBJECTIVE: This study aimed to evaluate the influence of chelating agents (EDTA, citric acid and Tetraclean) on glass fiber posts adhesion to root dentin. MATERIALS AND METHODS: Forty mandibular premolars single canals, with complete apical root, straight, circular cross sections were selected, accessed and had the cervical third prepared with Gates-Glidden drills, then included in resin, instrumented with ProTaper Universal and the root canal obturation was carried out. After, the samples were randomly divided into 4 groups (n = 10) to test the final irrigation solutions: G1:17% EDTA; G2:10% citric acid; G3: Tetraclean and G4: saline solution (control). After 30 days of storage (36.5° C and 100% humidity), the post preparation was performed leaving 4 mm of apical endodontic filling. Then, a fiber-glass post previously selected was coated with ED Primer adhesive system and resin sealer Panavia, installed and stored for 24 hours at 37°C. The samples were subjected to a tensile test with a constant speed of 1 mm/min with 2000 Kgf. The results were analyzed with the ANOVA test. RESULTS: The statistical analyzes indicated no significant differences between the groups (p > 0.05). CONCLUSION: The type of chelating agent used in the final irrigation of the endodontic treatment did not influence the tensile strength of the fixation system used to sealer the glass fiber posts to the intracanal dentin.