sogol saberi

 This study aimed to assess the photobiomodulation effects of blue and red lasers on the proliferation and osteogenic differentiation of periodontal ligament mesenchymal stem cells (PDLMSCs).

 PDLMSCs were cultured and tested in 4 groups. The first two groups were exposed to 445 nm diode laser irradiation (200 mW, 6 and 12 J/cm2), and the third group was exposed to
660 nm diode laser irradiation (50 mW, 4 J/cm2). The fourth group was also considered as the
control group without irradiation. Cell viability/proliferation was assessed by MTT assay. RUNX2, alkaline phosphatase (ALP), collagen type 1 (col1), and osteocalcin (OCN) were evaluated by RTPCR, and Alizarin red was used to evaluate the colonization. The data were analyzed by means of one-way analysis of variance.

 The results of our study showed that cell survival/proliferation in the second group was significantly lower than that in the control group on days 1 and 7 (P<0.05). RT-PCR showed a significant increase in osteogenic genes in all three laser groups compared to the control group (P<0.05). All groups showed a significant increase in calcium content compared to the control group (P<0.05). ALP activity also confirmed the osteoblastic differentiation of cells in laser groups.

 445 nm and 660 nm lasers with the studied parameters showed positive effects on the proliferation and osteoblastic differentiation of PDLMSCs.

This study assessed the effects of blue and Er:YAG lasers, fluoride varnish, and their combination on microhardness, and calcium and phosphorus content of demineralized enamel.

The primary Vickers microhardness of 28 third molars was measured and their enamel calcium and phosphorous content was quantified by energy-dispersive X-ray spectroscopy. They were then randomly assigned to five groups of 5% sodium fluoride (NaF) varnish, 445nm blue laser, Er:YAG laser, 5% NaF + 445nm blue laser, and 5% NaF + Er:YAG laser. The teeth then underwent pH-cycling to induce caries-like lesions. The surface microhardness of the teeth and the calcium and phosphorous content of demineralized enamel were measured again. Data were analyzed by one-way ANOVA and Tukey’s test (alpha=0.05).

NaF, NaF-diode laser, and NaF-Er:YAG laser groups experienced a significant increase in microhardness of demineralized enamel close to the baseline value (P<0.05). The efficacy of NaF-blue laser and NaF-Er:YAG laser was higher than NaF . In blue and Er:YAG laser groups, the mean final microhardness was significantly lower than the baseline microhardness. The percentage of phosphorus in all groups was similar to that of sound enamel. The percentage of calcium in NaF group was significantly lower than that of sound enamel and all other groups. The calcium content in other groups was similar to that of sound enamel.

Fluoride varnish had a synergistic effect with Er:YAG and blue lasers to increase the demineralized enamel microhardness; blue and Er:YAG lasers alone were less effective.

Due to the increasing prevalence and high mortality rate of oral squamous cell carcinoma (OSCC) and problems with its routine treatments, more recent modalities like photodynamic therapy (PDT) have been developed. PDT effectively destroys tumor cells with minimum side effects. Research on in vitro effects of PDT may be helpful in determining the molecular mechanisms responsible for its effectiveness and can lead to the development of more efficient techniques. The aim of this study was to review the use of PDT in OSCC among in vitro studies.

A literature search for English articles on PDT in OSCC was performed in PubMed, Scopus, Google Scholar, and Web of Science. Data were extracted based on the inclusion/exclusion criteria, which were detailed using the PICO framework: all eligible in vitro studies evaluating the effects of PDT on the viability of OSCC compared to controls without PDT were included.

Forty-one out of 567 studies were selected. The tongue was the most common OSCC site, 5-aminolevulinic acid was the most used photosensitizer (PS), cell viability/toxicity and apoptosis were the most evaluated outcomes, and lasers with wavelengths of 600-700 nm were the most common light sources and wavelengths respectively.

PDT showed promising effects on reducing the viability of OSCC cells. Cell lines from various sources or even those originating from the same location sometimes responded differently to the same protocol. Considering the favorable results obtained from natural PSs and regarding their additional health-promoting properties, their use in future investigations with different cell lines and light specifications is recommended.

Enamel demineralization around orthodontic brackets is a significant problem. This study aimed to compare the efficacy of Casein phosphopeptide amorphous calcium phosphate (CPP-ACP) varnish and fluoride varnish in preventing enamel demineralization around and beneath orthodontic brackets.

Twenty extracted premolars were randomly divided into two groups and orthodontic brackets were bonded to their buccal surface by composite. The amount of fluorescent light reflected back from the enamel at the mesial and distal of the bracket was measured using a DIAGNOdent™ pen. MI varnish (CPP-ACP) was applied on the exposed enamel of the distal half of the teeth in group I while FluoroDose varnish was applied on the same area in group II. The mesial half of the teeth served as the control group. All teeth underwent two demineralization cycles and after each cycle, enamel demineralization was quantified at mesial and distal areas (T1, T2). The brackets were then debonded, and area under the brackets was also measured by DIAGNOdent™ pen (T3). Data were analyzed using repeated measures ANOVA and paired t-test.

In both groups, significant difference was noted between the mesial and distal areas in degree of demineralization at T2 (P<0.001), but both of the varnishes had no effect on the degree of demineralization.

FluoroDose varnish and MI varnish were equally effective for enhancement of enamel resistance to demineralization with no superiority over each other.

The aim of this study was to assess the microtensile bond strength of three universal adhesives to dentin and enamel.

Sixty extracted human third molar teeth were chosen and divided into six groups regarding the adhesive (G-Premio Bond, Clearfil S3 Bond or Single Bond) and tooth surface. All the applied bonding agents were universal adhesives. The teeth were polished and the adhesives were applied; then the teeth were restored with composite resin. The samples were mounted in acrylic resin and sectioned. The specimens were subjected to a universal testing machine and the microtensile bond strength was measured. The failure mode of each specimen was determined under a stereomicroscope. Data were analyzed using two-way ANOVA (α=0.05).

The microtensile bond strength of G-Premio Bond to enamel and dentin was 11.79±8.27 and 17.55±9.47 MPa, respectively which was not significantly different from the values in Single Bond group (15.59±10.66 and 17.19±10.09 MPa to enamel and dentin, respectively; P>0.05). However, the values for Clearfil S3 Bond were 7.11±4.23 and 7.88±8.83 MPa to enamel and dentin, respectively, which were significantly lower than the values for G-Premio Bond (P<0.05). Scanning electron microscopic (SEM) images showed that the adhesive failure was dominant in both enamel and dentin groups and in all adhesive systems.

G-Premio Bond and Single Bond provided higher microtensile bond strength compared with Clearfil S3 Bond. Universal adhesives with their acceptable performance can be applied in self-etch mode on both enamel and dentin.

T Laser irradiation of dentin surface can affect its surface topography and roughness. Atomic force microscopy (AFM) is among the most efficient tools for determination of surface topography of natural biomolecules in nano-scales. Surface roughness affects plaque retention especially in the cervical region. This study aimed to assess and compare the obstruction of dentinal tubules and dentin surface roughness after irradiation of erbium: yttrium aluminum garnet (Er:YAG )and CO2 lasers for treatment of dentin hypersensitivity (DH) .
Five disc-shaped samples measuring 3 mm in thickness were fabricated by horizontal sectioning of the cervical area of five extracted human molars using a low speed saw. Each disc was divided into 3 segments by a bur under water coolant. The three segments of each disc were placed on a glass slide. First segment: No intervention (control group). Second segment: Er:YAG laser irradiation (2940 nm, 50 mJ, 10 Hz and 0.5 W, 30 seconds) along with water coolant. Third segment: CO2 laser irradiation (10600 nm, 80 Hz, 0.3 W, 30 seconds) along with water coolant. After that, the surfaces underwent non-contact AFM. The diameters of dentinal tubules as well as surface roughness were then measured and statistically analyzed using repeated measures ANOVA.
The surface roughness parameters (Ra, Rq) showed increased roughness after laser irradiation and this increase in roughness after Er:YAG laser application was significant compared to the control group (P = 0.048). However, CO2 laser caused no significant change in surface roughness. Also, after Er:YAG laser application, fewer open dentinal tubules were observed and the remaining open tubules had a smaller diameter.
Based on the results, Er:YAG laser irradiation obstructs the dentinal tubules and increases the dentin surface roughness. This increase in surface roughness can cause microbial plaque retention and increase the risk of caries and periodontal disease. Application of CO2 laser (compared to Er:YAG) lead to slight but clinically significant obstruction of dentinal tubules and surface roughness

The aim of this study is to analyze the effect of G-Bond and Z-PRIME Plus on the bond strength between prefabricated zirconia posts and the canal wall.
Material and The study was carried out on 21 premolar teeth with similar conditions. The collected samples were cut at the CEJ. After root canal treatment of the roots, the post space was prepared with a length of 10mm. The samples were randomly allocated into two groups of 10. G-bond was used in one group and Z-PRIME plus in the other to prepare the posts’ surface. After cementation and mounting the samples in polyester, the post was cut from the apical area into three equal sections. The bond strength of the samples was tested using the push out on a universal testing machine. The acquired data was analyzed using the T-Test.
The average for the control group was 14.3N, the G-bond group had an average of 27.6±11.8N and the Z-PRIME plus group’s average was 27.4±13.4N. There is no statistically significant relationship between the two groups (P There is no statistically significant relationship between the G-bond and Z-prime plus groups and both products increase the bond strength of prefabricated zirconia posts.

Considering the importance of the clinical significance of the elongated styloid process, this study aimed to assess the prevalence and pattern of calcification and elongation of the styloid process on digital panoramic radiographs of an Iranian population.
This study was conducted on 500 digital panoramic radiographs of patients over 18 years old with visible styloid processes. The length of styloid processes was measured by software, and the length>30mm was considered as elongated. Prevalence and pattern of elongation and calcification were determined according to the classification proposed by Langlais. The associations of age, sex, and the jaw side of elongation was determined using generalized estimating equations with exchangeable matrix and binary logistic model.
Elongation of styloid process was observed in 177 (17.7%) of 1000 evaluated processes were elongated. The Type I pattern of elongation (n=80, 45%) and type A pattern of calcification (n=69, 39%) had the highest frequency. Although the prevalence of elongation seemed to be higher in males, the difference was not significant (P=0.11). No significant association was observed between the side of jaw and elongation (P=0.54). Elongation was more common in the 40-59-year-old group compared to The prevalence of elongated styloid process often considered as an anatomical variation and has been reported differently in the literature. Dentists should pay more attention to it during clinical examination especially in the case of pain in head and neck.

Discoloration is a major concern with regard to the use of tooth-colored restorations. Type of restorative material and surface treatment are believed to play a role in this regard. This study sought to compare the color change of glazed and polished dental porcelain after 30 days of immersion in chlorhexidine (CHX).
In this in vitro, experimental study, 20 discs with 10 mm diameter and 2 mm thickness were fabricated of A1 shade of Noritake porcelain using a gypsum mold. All samples had one opaque layer.
They were then randomly divided into two groups of 10. Glaze powder was added to porcelain in group 1, and group 2 was polished using a polishing kit. The CIE L*a*b color parameters of samples were then measured using a spectrophotometer. All samples were immersed in 0.02% chlorhexidine solution for 30 days and color parameters were then measured again. Change in each color parameter was compared between the two groups (polished and glazed) using t-test.
After 30 days of immersion in CHX, ∆E was 0.76±0.16 in the glazed and 0.89±0.16 in the polished group. The difference in this regard between the two groups was not significant (P=0.092).
Both polishing and glazing confer optimal color stability to dental porcelain.