Viability of bacteria associated with root caries after Nd:YAG laser application in combination with various antimicrobial agents: An in vitro study.

BACKGROUND: The neodymium-doped yttrium aluminum garnet (Nd:YAG) laser has various therapeutic applications in dentistry, including the treatment of dentin hypersensitivity and the bacterial reduction therapy in periodontology. The addition of antimicrobial agents may enhance the impact of the laser on bacterial viability. OBJECTIVES: This in vitro study aimed to assess the effect of Nd:YAG laser application in combination with various chemical antimicrobial agents, including hydrogen peroxide (H2O2), sodium hypochlorite (NaOCl), chlorhexidine (CHX), and sodium fluoride (NaF), on the viability of bacteria implicated in the etiology of root caries. MATERIAL AND METHODS: Three oral bacterial species were examined: Streptococcus mutans (S. mutans); Streptococcus sanguinis (S. sanguinis); and Enterococcus faecalis (E. faecalis). The bacteria were grown in broth at 37°C, and then treated with the chemical agents and/or irradiated with an Nd:YAG laser for 30 s. Each treatment modality was repeated 3 times: group 1 - no treatment; group 2 - 0.5% H2O2; group 3 - 0.5% NaOCl; group 4 - 0.12% CHX; group 5 - 2% NaF; group 6 - Nd:YAG laser irradiation; group 7 - laser and 0.5% H2O2; group 8 - laser and 0.5% NaOCl; group 9 - laser and 0.12% CHX; and group 10 - laser and 2% NaF. The viability of the bacteria was determined by plating them, counting viable colonies, converting the data into colony-forming units (CFUs)/mL, and transforming them into the log form. Statistical analysis was performed using the two-tailed paired t test. RESULTS: Irradiation with an Nd:YAG laser alone did not show a statistically significant effect against any of the bacterial species. The only effective antimicrobial used alone was CHX for S. mutans. Chlorhexidine with Nd:YAG resulted in a greater reduction in S. mutans and E. faecalis than either treatment alone. Meanwhile, H2O2 with Nd:YAG also showed an enhanced S. mutans reduction. Treatment with 0.5% NaOCl in conjunction with Nd:YAG brought the most significant reduction in viability for all bacteria in comparison with other treatment modalities. CONCLUSIONS: The Nd:YAG laser combined with 0.5% NaOCl resulted in the most substantial reduction in bacterial survival as compared to the antimicrobials or the Nd:YAG laser used alone.

The In Vitro Effect of Laser Irradiation (Er:YAG and CO2) and Chemical Reagents (Hydrogen Peroxide, Sodium Hypochlorite, Chlorhexidine, or Sodium Fluoride) Alone or in Combination on Reducing Root Caries Bacteria.

(1) Lasers have been used for the treatment of dentinal hypersensitivity and bacterial reductions in periodontology. The purpose of this in vitro study was to evaluate the effect of Carbon Dioxide (CO2) and Erbium-doped Yttrium Aluminum Garnet (Er:YAG) lasers with chlorhexidine (CHX), hydrogen peroxide (H2O2), sodium hypochlorite (NaOCl), or sodium fluoride (NaF) on the viability of oral bacteria associated with root caries. (2) Streptococcus mutans, Streptococcus sanguinis, and Enterococcus faecalis were grown in Brain Heart Infusion (BHI) broth, diluted to an OD660 of 0.5, and treated with antiseptics with or without simultaneous irradiation with the Er:YAG and CO2 lasers for 30 s repeated three times. The treatment groups consisted of 1: no treatment, 2: 0.5% H2O2 alone, 3: 0.5% NaOCl alone, 4: 0.12% CHX alone, 5: 2% NaF alone, 6: laser alone, 7: laser with 0.5% H2O2, 8: laser with 0.5% NaOCl, 9: laser with 0.12% CHX, and 10: laser with 2% NaF for both lasers. The microbial viability was determined through plating and viable colonies were counted, converted into CFU/mL, and transformed into log form. The statistical analysis was performed using a two-tailed paired t-test. (3) The use of CO2 and Er:YAG lasers alone failed to show statistically significant antibacterial activity against any of the bacteria. The only effective monotreatment was CHX for S. mutans. The combined treatment of 0.5% NaOCl with Er:YAG produced the greatest reduction in overall viability. (4) The combination of the Er:YAG laser with 0.5% NaOCl resulted in the largest reduction in bacterial survival when compared to monotherapies with antimicrobial solutions or lasers.

Trophoblast retrieval and isolation from the cervix (TRIC) for noninvasive prenatal screening at 5 to 20 weeks of gestation.

OBJECTIVE: To use trophoblast cells accumulating in the endocervical canal at the beginning of pregnancy for noninvasive prenatal testing. DESIGN: Prospective, double-blinded test for fetal gender. SETTING: Academic medical center. PATIENT(S): Fifty-six women with singleton pregnancies at gestational age 5-20 weeks. INTERVENTION(S): Isolation of fetal cells from resident maternal cells in endocervical specimens using anti-human leukocyte antigen G coupled to magnetic nanoparticles; cell phenotyping immunofluorescently with a panel of trophoblast subtype-specific proteins; DNA integrity assessment with terminal dUTP nick-end labeling (TUNEL); and polymerase chain reaction (PCR) and fluorescent in situ hybridization (FISH) to detect sex chromosomes in individual cells. MAIN OUTCOME MEASURE(S): Trophoblast phenotype, TUNEL index, and percentage male cells. RESULT(S): The women were given a routine Papanicolaou test; fetal genders were verified from medical records. Recovery after immunomagnetic isolation averaged 746±59 cells across gestational age, with 99% expressing chorionic gonadotropin, whereas the depleted cell fraction expressed none. The isolated cells had an extravillous trophoblast phenotype and intact nuclear DNA (>95%). Fetal gender was determined in 20 specimens without error by PCR. The FISH analysis of isolated cells from male specimens validated their fetal origin. CONCLUSION(S): Noninvasive prenatal testing is feasible beginning at a gestational age of 5 weeks.