Disinfection by methylthionine chloride and chitosan in combination with Photo radiation therapy on caries affected dentin nano hardness, adhesive integrity, and bond failure

OBJECTIVE

The aim of the study was to assess the disinfection efficacy, bond integrity, and nano hardness of caries-affected dentin (CAD) surface bonded to resin cement when disinfected with chlorhexidine (CHX), Methylene blue activated by Photodynamic therapy (MB-PDT), chitosan, silver diamine fluoride (SDF), chitosan activated by PDT, and SDF-diode laser against S. mutans.

MATERIALS AND METHODS

A total of 60 human mandibular molars were extracted non-traumatically and gathered using ICDAS criteria. The dentin surface was prepared, leaving CAD to receive a disinfection procedure. After inoculation with S. mutans, the CAD samples were divided into six groups and disinfected with various disinfectants (n = 10) CHX, MB-PDT, chitosan, chitosan-PDT, SDF, and SDF+ diode laser. Survival rates of S. mutans were analyzed following the restoration of samples with resin cement via the etch and rinse method to assess SBS. Also, nano hardness was analyzed. Statistical analysis was performed by using the ANOVA and the Tukey multiple test (p<0.05). The Kruskal-Wallis test was used to evaluate the change in survival rate.

RESULTS

Related to the survival rates, the SDF+ diode laser displayed the highest reduction in S. mutans levels and chitosan presented the lowest level of disinfection. The intergroup comparison revealed that CHX and chitosan-PDT displayed comparable outcomes of S. mutans survival rate to that of SDF+ diode laser (p>0.05). Likewise, MB-PDT and SDF displayed a comparable survival rate of S. mutans to Chitosan disinfection (p>0.05). Considering SBS and nano hardness, the highest SBS and NH were exhibited by the SDF+ diode laser, and the lowest SBS and NH values were exhibited by MB-PDT. The intragroup comparison revealed that CAD specimens disinfected with Chitosan-PDT showed comparable SBS and NH values to the SDF+ diode laser (p>0.05). CHX, chitosan, and SDF exhibited bond values and NH comparable to MB-PDT (p<0.05).

CONCLUSIONS

Synergistic use of Silver diamine fluoride with diode laser and chitosan activated by PDT can be used as an alternative to CHX for controlling S. mutans growth, promoting enhanced bond efficacy and nano hardness for bonding resin cement to the caries-affected dentin.

Correlation between hamstring muscle tightness and incidence of low back pain in female students at Jouf University, Saudi Arabia

OBJECTIVE

The current study aimed at determining the difference in hamstring tightness between dominant and non-dominant legs and to detect the correlation between LBP and hamstring tightness.

PATIENTS AND METHODS

One hundred females with hamstring tightness of at least 15 degrees have been included in the study. Hamstring shortening was examined by the Active Knee Extension test (AKE) and Straight Leg Raising test (SLR), whilst the functional disability' degree was measured by Oswestry Disability Index (ODI).

RESULTS

The straight leg raising and the AKE of the dominant leg were significantly more flexible than the non-dominant ones. There was a weak positive non-significant correlation between ODI and AKE of the dominant side (r = 0.162, p = 0.1) and the non-dominant side (r = 0.071, p = 0.48). There was a weak negative non-significant correlation between ODI and SLR of the dominant side (r = - 0.29, p = 0.77) and the non-dominant side (r = - 0.53, p = 0.6).

CONCLUSIONS

There was no relation between the degree of hamstring tightness and LBP in female students at Jouf University.