Clinical comparison of whitening efficacy and tooth sensitivity of different concentrations of hydrogen peroxide photoactivated with violet or blue LEDs.

This study evaluated the photoactivation of hydrogen peroxide gels at different concentrations using blue or violet LED in terms of whitening efficacy and tooth sensitivity. Forty patients were randomly divided into 4 groups: HP6V (violet LED and 6% hydrogen peroxide), HP6B (blue LED and 6% hydrogen peroxide), HP35V (violet LED and 35% hydrogen peroxide), and HP35B (blue LED and 35% hydrogen peroxide). The L*, a* and b* values were measured before, 1 week and 3 months after treatment, and the ΔE and ΔWID values were calculated. Tooth sensitivity was measured using a visual analogue scale (VAS) before, immediately after, and 24 h after bleaching. The ΔE, ΔWID and bleaching sensitivity values were subjected to the ANOVA test and Bonferroni post-test. HP35V and HP35B showed higher whitening efficacy than HP6VL, while HP6V did not show statistical differences compared to the other groups. Regarding bleaching-related sensitivity, the HP6V and HP6B groups presented the lowest values when compared to HP35V and HP35B. HP6V showed whitening efficacy comparable to HP35V and HP35B but with reduced tooth sensitivity. TRIAL REGISTRATION NUMBER: NCT06165458; registration date: 12/09/2023.

Ultrastructural changes in bacterial membranes induced by nano-assemblies ß-cyclodextrin chlorhexidine: SEM, AFM, and TEM evaluation.

Chemical hosts bind their guests by the same physical mechanisms as biomolecules and often display similarly subtle structure activity relationships. The cyclodextrins have found increasing application as inert, nontoxic carriers of active compounds in drug formulations. The present study was conducted to prepare inclusion complexes of chlorhexidine:ß-cyclodextrin (Cx:ß-cd), and evaluate their interactions with bacterial membrane through: scanning electron microscopy (SEM) and transmission electron microscopy (TEM); and measuring morphology alterations, roughness values, and cell weights by atomic force microscopy (AFM). It was found that the antimicrobial activity was significantly enhanced by cyclodextrin encapsulation. SEM analysis images demonstrated recognizable cell membrane structural changes and ultrastructural membrane swelling. By TEM, cellular alterations such as vacuolization, cellular leakage, and membrane defects were observed; these effects were enhanced at 1:3 and 1:4 Cx:ß-cd. In addition, AFM analysis at these ratios showed substantially more membrane disruption and large aggregates mixing with microorganism remains. In conclusion, nanoaggregates formed by cyclodextrin inclusion compounds create cluster-like structures with the cell membrane, possibly due to a hydrogen rich bonding interaction system with increasing surface roughness and possibly increasing the electrostatic interaction between cationic chlorhexidine with the lipopolysaccharides of Gram negative bacteria.

Effect of photodynamic therapy as an adjuvant to non-surgical periodontal therapy: Periodontal and metabolic evaluation in patients with type 2 diabetes mellitus.

BACKGROUND: This pilot study aimed to evaluate the effect of antimicrobial photodynamic therapy (aPDT) as an adjuvant to non-surgical periodontal therapy (NSPT) on periodontal status and glycemic control in patients with type 2 diabetes mellitus and generalized chronic periodontitis. METHODS: Twelve patients were evaluated at five time points: during the preparation of the patient (T0), during the treatment phase (T1) and after 30 (T2), 90 (T3) and 180 (T4) days. The patients had a mean age of 52.2 years and a 9.58-year history of diabetes, on average, and were divided into two randomized treatment groups: 6 patients received NSPT combined with aPDT (G1) and 6 patients received only NSPT (G2). The aPDT was applied associating the photosensitizing agent methylene blue (10 mg/ ml) with a red laser (660 nm-40 mW). The total time of exposure was 2 min per tooth. RESULTS: Whitin the limitation of this study, the results showed that the plaque index reduced significantly only in the control group (p = 0.02) at T2 (30 days). For bleeding on probing, both groups showed a significant reduction between T1 and T2, with no difference between groups G1 and G2. Regarding the probing depth, there were no differences between groups, but the parameters decreased over time when compared to T1. The glycated haemoglobin and fructosamine levels did not significantly differ between or within the groups at any time point. CONCLUSION: When NSPT was combined with aPDT, no additional benefits were observed for the periodontal and metabolic clinical parameters.

Antimicrobial effect of photodynamic therapy in carious lesions in vivo, using culture and real-time PCR methods.

BACKGROUND: The aim of this study was to evaluate the antimicrobial effect of photodynamic therapy (PDT) in carious lesions in vivo by culture and real-time PCR methods. METHODS: Ten teeth with deep active carious lesions were selected and five portions of carious dentin were removed for each tooth. Two increments were used as control, to represent the superficial and deep dentin, respectively. Methylene blue at 100mg/L was placed in contact with the cavity for 5min, before being irradiated with a halogen light source for 1min. Then, after PDT, other three portions were removed. The samples were processed in laboratory and the number of viable cfu was obtained. The real-time PCR analyses were performed in two increments of carious dentin, removed before and after PDT. The Streptococcus mutans DNA was isolated from carious dentin samples and amplification and detection of DNA were performed with real-time PCR. The cavities were then restored with glass-ionomer cement. RESULTS: Using conventional culture methods, the results demonstrated that viable bacteria were significantly reduced in all of the agar plates following photosensitization. No difference was found between both groups regarding S. mutans DNA quantification by real-time PCR. CONCLUSION: Although PDT may not affect the number of S. mutans DNA copies immediately after the treatment, clear reduction of the number of cfu was found. Despite its promising use for eliminating bacteria in dental caries treatment, further studies are necessary to establish an effective clinical protocol for the PDT.

Estudo piloto da análise comparativa da atividade antimicrobiana da PDT e agentes irrigantes em canais radiculares inoculados com Enterococcus faecalis "in vitro" / A pilot study of the comparative analysis of the antimicrobial activity of PDT and irrigating agents in root canals inoculated with Enterococcus faecalis "in vitro"

Objetivo:O presente estudo piloto "in vitro" avaliou o efeito antimicrobiano do hipoclorito de sódio, clorexidina, terapia fotodinâmica e do óleo de girassol ozonizado utilizados como agentes irrigantes na eliminação do Enterococcus faecalis em canais radiculares de dentes humanos extraídos.Métodos:Sessenta raízes de dentes unirradiculares (n = 60) foram selecionadas e autoclavadas para realização do experimento em fluxo laminar. Para a realização do teste de infiltração, confeccionou-se um dispositivo para cada denteque permitiu a contaminação por Enterococcus faecalis e posterior preparo químico-mecânico. As amostras foram submetidas ao preparo biomecânico com diâmetro cirúrgico correspondente à lima #45 e mesma conicidade nos terços médio e cervical e receberam protocolo de desinfecção com hipoclorito de sódio a 2,5% (NaOCl), Clorexidina a 2% (CHX), óleo de girassol ozonizado a 2400ppm (OGO), PDT após irrigação com soro fisiológico (PDT+S) e PDT após irrigação com hipoclorito de sódio a 2,5% (PDT+H). As dez raízes restantes constituíram os controles positivo e negativo, sendo cinco dentes para cada grupo. Os controles positivos foram infectados e não foi utilizado nenhum agente irrigante. Os controles negativos foram compostos por dentes não contaminados pelo E. faecallis. Resultados: Os resultados da contagem de UFC/mL total e análise descritiva foram realizados. NaOCl e PDT+H apresentaram crescimento bacteriano inferiores aos valores de referência e foi considerado nulo. CHX e PDT+S apresentaram crescimento bacteriano baixo e OGO apresentou crescimento bacteriano moderado. Conclusão: NaOCl e PDT+H apresentaram melhor desempenho em relação aos demais protocolos de desinfecção utilizados. OGO apresentou crescimento bacteriano moderado sugerindo inviabilidade de sua utilização isolada em protocolos de desinfecção em endodontia. (AU)

Aim: The present "in vitro" pilot study evaluated the antimicrobial effects of sodium hypochlorite, chlorhexidine, photodynamic therapy, and ozonated sunflower oil, which were used as irrigating agents in the elimination of Enterococcus faecalis in the root canals of extracted human teeth. Methods: Sixty roots of single-root teeth (n = 60) were selected and autoclaved to perform the laminar flow experiment. To perform the infiltration test, a device was constructed for each tooth, which allowed for contamination by Enterococcus faecalis, and the tooth's subsequent chemical-mechanical preparation. The samples were submitted to biomechanical preparation with surgical diameter, corresponding to file #45 and the same taper in the middle and cervical thirds, and received a disinfection protocol with 2.5% sodium hypochlorite (NaOCl), chlorhexidine 2% (CHX), ozonized sunflower oil at 2400ppm (OGO), PDT after irrigation with saline solution (PDT+S), and PDT after irrigation with 2.5% sodium hypochlorite (PDT + H). The remaining ten roots were positive and negative controls, with five teeth in each group. Positive controls were infected, and no irrigating agent was used. Negative controls consisted of teeth that were not contaminated by E. faecallis. Results: The results of the total CFU count and descriptive analysis were performed. NaOCl and PDT+H presented a bacterial growth of much lower t than the reference values and was considered null. CHX and PDT+S presented low bacterial growth, while OGO presented moderate bacterial growth. Conclusion: NaOCl and PDT + H presented better performance in relation to the other disinfection protocols used in this study. OGO presented moderate bacterial growth, suggesting its unviable use in endodontic disinfection protocols. (AU)

Evaluation of antibacterial photodynamic therapy effects on human dental pulp cell cultures.

BACKGROUND: The antibacterial photodynamic therapy (aPDT) has been used in dentistry against oral microorganisms because of its excellent biocide effect. However, for carious lesions applications, there is little evidence that this therapy is safe for the pulp tissue. OBJECTIVE: This study evaluates the effects of an aPDT protocol on human pulp cells in vitro. METHODS: Pulp cells isolated from dental pulp were exposed to an aPDT protocol associating methylene blue (MB) at concentrations of 0.0125, 0.025 and 0.050mg/ml and red laser irradiation using a continuous-wave indium-gallium-aluminum-phosphide (InGaAlP) diode laser (λ=660nm, 40mW, 2.4J, 60J/cm(2) for 1min). Pre-irradiation time was 5min for each MB concentration. Cell viability was determined by MTT assay and activity of alkaline phosphatase was assessed by BCIP-NBT assay. Type of aPDT-induced cell death was assessed by flow cytometry. Data was statistically compared (ANOVA followed by Tukey' or Bonferroni's post hoc tests). RESULTS: aPDT was able to kill pulp cells in a dye concentration-dependent manner. The cellular viability was significantly reduced when used MB at 0.025 or 0.050mg/ml concentrations (p<0.0001). At these concentrations, aPDT-induced cell death occurred mostly by necrosis. Alkaline phosphatase activity was significantly reduced in all experimental groups (p<0.001). Pulp cells showed suitable viability when MB at 0.0125mg/ml was exposed to laser irradiation. CONCLUSIONS: aPDT with MB at 0.0125mg/ml may represent a low-risk therapy for restorative dentistry applications. aPDT protocol using concentrations above 0.025mg/ml of MB associating red laser irradiation may be harmful for dental pulp cells.

Clinical evaluation of packable resin Class I restorations after 7 years

Aims: Compactable composite resins have been indicated as amalgam substitutes. However, longitudinal clinical trials are necessary to verify their wear resistance and integrity maintenance. The purpose of this study was to evaluate the clinical performance of a packable resin in Class I restorations after 7 years. Methods: Forty restorations were placed in 15 young patients aged 13 to 30 years. The restorative material (Prodigy/OptiBond-KERR®) was used according to standard recommendations. The restorations were assessed at baseline at the year 2000 and after 2 and 7 years according to the USPHS (United State Public Health Service) criteria. Results: After 7 years, 50% of the restorations were scored Alpha and 37.5% scored Bravo for color match, marginal discoloration and marginal adaptation. Secondary caries were observed in only one restoration and none of them presented postoperative sensibility. Conclusion: In accordance with the USPHS method used, the packable resin presented appropriate clinical performance after a 7-year clinical evaluation.

Análisis de la eficacia de agentes químicos de desinfección en materiales elastoméricos / Analysis of the efficacy of disinfective chemical agents on elastomeric materials

El objetivo de este estudio fue evaluar la eficacia de agentes de desinfección indicados para polisulfuros (mercaptanos), poliéteres y siliconas por condensación y por adición. Fueron confeccionadas noventa muestras de cada material, siendo treinta de ellas contaminadas con Streptococcus mutans o Staphylococcus aureus o Candida albicans. De cada solución microbiana fueron retiradas diez muestras del polisulfeto y de ambas las siliconas, que fueron inmersas por diez minutos en glutaraldehído al 2 por ciento y otras diez inmersas en agua destilada estéril (control negativo). Después de un nuevo lavado en agua destilada, las muestras fueron transferidas a medios de cultivo estériles. Las diez muestras restantes no fueron sometidas al agente de desinfección y fueron transferidas a medios asociados a agentes antimicrobianos específicos (control positivo). La turbidez de los medios de cultivo fue evaluada como indicativo del crecimiento microbiano siguiéndose a la incubación por 24 h a 37O C y se realizó la dilución y sembrado en placas de Petri para contar las colonias. Para el poliéter fue ejecutado el mismo procedimiento, pero el agente de desinfección usado fue el hipoclorito de sodio a 1. No hubo turbidez comprobatoria del crecimiento microbiano en ninguno de los medios de cultivo que contenían los especimenes sometidos a los agentes de desinfección. Se concluyó que el glutaraldehído al 2 por ciento es un agente de desinfección eficaz para el polisulfuro y para las siliconas por adición y por condensación, así como el hipoclorito a 1 por ciento es eficaz para el poliéter, para los microorganismos evaluados

The aim of this in vitro study was to evaluate the disinfection efficacy of elastomeric impression materials such as polysulfides, polyethers, condensation and addition silicones. Ninety samples of each material were made and every thirty samples contaminated with Streptococcus mutans or Staphylococcus aureus or Candida albicans. From each microbial solution there were taken ten samples of polysulfide and of both silicones which were immersed for ten minutes in a 2% glutaraldehyde solution and other ten immersed in sterile distilled water (negative control). After being washed again in distilled water, the samples were transferred to sterile culture medium. The last ten samples were not submitted to any disinfection agent and were transferred to mediums associated with specific anti-microbial agents (positive control). The turbidity of the culture mediums was evaluated as an indication of the microbial growth after a period of 24-hour incubation at 37oC and the dilution and seeding in Petri dishes were done to count the colonies. The same procedure was done for the polyether, but the disinfection agent used was 1% sodium hypoclorite. There was no proved turbidity of the microbial growth in any of the culture mediums which had samples submitted to the disinfection agents tested. It was concluded that the 2% glutaraldehyde is an effective disinfection agent to polysulfides and to both condensation and addition silicones, as well as 1% sodium hypoclorite is effective to polyether, for the tested microorganisms.

O objetivo deste estudo in vitro foi avaliar a eficácia de agentes de desinfecção indicados para polissulfetos, poliéteres e siliconas de condensação e adição. Foram confeccionadas noventa amostras de cada material, sendo cada trinta contaminadas com Streptococcus mutans, Staphylococcus aureus ou Candida albicans. De cada solução microbiana foram retiradas dez amostras do polissulfeto e de ambas as siliconas, que foram imersas por dez minutos no glutaraldeído a 2% e outras dez imersas em água destilada estéril (controle negativo). Após nova lavagem em água destilada, as amostras foram transferidas para meios de cultura estéreis. As dez amostras restantes não foram submetidas ao agente de desinfecção e foram transferidas para meios associados a agentes antimicrobianos específicos (controle positivo). A turbidez dos meios de cultura foi avaliada como indicativo de crescimento microbiano após incubação por 24 h a 37O C e realizou-se a diluição e semeadura nas placas de Petri para contagem de colônias. Para o poliéter foi executado o mesmo procedimento, porém o agente de desinfecção empregado foi o hipoclorito de sódio a 1%. Não houve turvação comprobatória de crescimento bacteriano em nenhum dos meios da cultura que continham corpos de prova submetidos aos agentes de desinfecção. Concluiu-se que o glutaraldeído a 2% é um agente de desinfecção eficaz para o polissulfeto e para as siliconas por adição e por condensação, assim como o hipoclorito a 1% é eficaz para o poliéter, para os microorganismos testados.