The Effect of Various Lasers on the Bond Strength Between Orthodontic Brackets and Dental Ceramics: A Systematic Review and Meta-Analysis

The Effect of Er Laser Treatment on the Surface Roughness of Enamel and Bacterial Adhesion

Objective: To investigate the effects of laser-treated enamel surface roughness on the adhesion of Streptococcus mutans. Methods: A total of 176 premolars extracted for subtractive orthodontic treatment were collected. Samples were randomly divided into four groups: control group, 35% phosphoric acid, Er:YAG laser, Er,Cr:YSGG laser. Surface roughness was detected using three-dimensional white light interferometric surface topography (n = 8/group), and surface morphology was observed by scanning electron microscope [(SEM), n = 8/group]. Samples were cultured in S. mutans solution for 12 h, 1 day, and 2 days. The colony forming units on the enamel surface were calculated (n = 8 per time point). The biofilm and activity of S. mutans were observed by SEM (n = 2/group) and confocal laser scanning microscope (n = 2/group). Correlation analysis was carried out between bacterial adhesion on the enamel surface at different time points and the surface roughness of the enamel treated by different methods. Results: After Er:YAG and Er,Cr:YSGG laser etching, the surface roughness of enamel increased (p < 0.05), but there was no difference in S. mutans adhesion and biofilm morphology after 1 day compared with traditional phosphoric acid etching (p > 0.05). S. mutans adhesion was positively correlated with the enamel roughness in the early stage. Conclusions: Er:YAG and Er,Cr:YSGG laser etching may be an alternative to traditional phosphoric acid etching.

The Effect of Collagen-Propolis-Eucalyptus Hydrogel in Wound Healing: An In Vivo Study (Rat Model)

BACKGROUND

A skin injury could cause serious damage, as it is the outermost layer. Treatment can heal superficial injuries perfectly, but deep wounds can barely heal it. A wound not treated correctly can lead to severe health problems and even death.

AIM

This study aims to investigate the role of collagen-propolis-eucalyptus hydrogel in wound healing in rats.

METHODS AND MATERIALS

Collagen solution was prepared, and then the extract of propolis and eucalyptus was prepared. Four groups (collagen-propolis-eucalyptus, collagen-eucalyptus, collagen-propolis hydrogels and control groups) were prepared, and their biocompatibility was evaluated by the MTT test assay; Then the anti-bacterial activity against Staphylococcus aureus and Escherichia coli was evaluated. The animal test was investigated during 7, 14 and 21 days by histopathology.

RESULTS

The MTT test did not show significant cell cytotoxicity, and the percentage of cell survival was more than 90% for 24, 48 and 72 h. The effect of the anti-bacterial hydrogel collagen-propolis-eucalyptus group compared to the collagen-eucalyptus and collagen-propolis groups was much higher. The percentage of wound contraction was recorded in the collagen-propolis-eucalyptus group and it increased in all the groups over time. The results showed that the percentage of wound contraction and repair was significant in the macroscopic and microscopic evaluations.

CONCLUSION

The results showed the effectiveness of natural hydrogel in increasing the healing process of the wound, and it is possible to use this hydrogel natural collagen-eucalyptus-propolis as a suitable option because of its accessibility and low cost.

The effect of different intracanal irrigants on the push-out bond strength of dentin in damaged anterior primary teeth

This experimental study investigated the effect of different intracanal irrigants on the push-out bond strength of dentin in damaged anterior primary teeth. The crowns of 90 anterior primary teeth were sectioned horizontally, 1 mm above the cementoenamel junction (CEJ). Following canal preparation with K-files, all groups except the negative control received normal saline irrigation. Canals were then irrigated with either 3% or 5.25% sodium hypochlorite (NaOCl), 2% or 0.2% chlorhexidine (CHX) solution (except negative and positive controls). The roots were filled with Metapex material and covered with a calcium hydroxide liner. In root canals, the bond was applied by self-etching and then light-cured for 20 seconds before canals were restored incrementally with composite. Stereomicroscopes were used to assess failure patterns. Push-out bond strengths (MPa ± SD) were: 3% NaOCl (16.92 ± 5.78), 5.25% NaOCl (8.96 ± 3.55), 2% CHX (14.76 ± 5.56), and 0.2% CHX (7.76 ± 2.93). Significant differences were seen across the irrigants regarding the push-out bond strength of dentin sections (P <0.001). The most frequent failures were adhesive and cohesive. NaOCl and CHX irrigants increased the push-out bond strength compared to controls. Compared to controls, both 3% NaOCl and 2% CHX irrigants significantly increased the push-out bond strength of dentin in non-vital anterior primary teeth.

Evaluation and assessment of the wettabilty and water contact angle of modified poly methyl methacrylate denture base materials against PEEK in cast partial denture framework: an in vitro study

INTRODUCTION

The prevalence of adults with partially dental arches is expected to be more than imagined and patients requiring replacement of missing teeth are slowly increasing in number too. Removable partial dentures are known to provide for substantial replacement for the missing teeth with also added advantages when compared to fixed or implant prosthesis, mainly in elderly patients. Denture base material performance and durability are greatly influenced by wettability and water contact angle. In the case of dentures; adequate moisture distribution is necessary to ensure excellent wettability which has an influence on comfort and oral health. The purpose of conducting this study was to find out whether the advancements made using PEEK (Polyether ether ketone) would prove to be more beneficial than the current upgrades in the current material spectrum.

MATERIALS AND METHODS

This study was performed under in vitro conditions. All the fabrication and processing was done only by one operator. The materials used were divided into three groups each comprising 20 samples. Group A was modified polymethylmethacrylate (Bredent Polyan), Group B was polyoxymethylene acetal resin (Biodentaplast) and Group C was PEEK. An Ossila Goniometer was used to measure the contact angle. The three types of liquids used for the testing included distilled water, natural saliva and mouth wetting solution (Wet Mouth Liquid, ICPA India). Human saliva was collected from an individual with no medical conditions and normal salivary secretion.

RESULTS

The data was analyzed using One-way ANOVA test and a pairwise comparison using the Post Hoc Tukey's Honest Significant Difference. Table 1 consists of the mean water contact angles of the denture base materials and mean contact angles of various denture base materials. In saliva, mouth wetting solution and distilled water, the highest mean and least mean contact angle was seen in Polyan and Biodentaplast respectively. A signicant difference was seen between PEEK and Polyan and Biodentaplast and Polyan on further comparison.

CONCLUSION

From the resources and the materials at our disposal, it could be concluded that Polyan, Biodentaplast and PEEK and could be used as viable options in cast partial denture framework.