Dental Research Journal
Volume:20 Issue: 4, Apr 2023

The goal of this study is to determine the effect of different sandblasting particles and dental adhesive systems on the repair strength of dimethacrylate‑based composite resins.

In this in‑vitro study, 96 specimens of X‑trafil composite blocks were prepared and divided into eight groups (n = 12). Four groups were sandblasted with Aluminum Oxide (AL) and four other groups with Bio‑Active Glass particles (BAG). A two‑component silane was applied on the surface of all the samples after phosphoric acid etching and rinsing. Two groups of the sandblasted specimens were treated with Clearfil SE Bond (CSB) and the other two groups were treated with Single Bond Universal (SBU) and new composite was bonded to the prepared surfaces. Half of the specimens in each group were thermocycled. Shear force was applied to the bonded composite using a universal testing machine with a crosshead speed of 0.5 mm/min and mean shear bond strength (MSBS) was calculated (MPa). The data was analyzed using Kruskal–Wallis and Man–Whitney U‑tests with the significance level of 0.05.

Significant differences were observed between different groups (P < 0.001). The highest and the lowest MSBS of the thermocycled samples were reported 18.88 MPa with application of AL and SBU and 11.46 MPa with the application of AL and CSB, respectively. No significant difference was observed with application of BAG particles after thermocycling.

Effect of AL on repair shear bond strength of composite resins is affected by bonding type. Bonding type did not affect repair shear bond strength of BAG. Thermocycling reduced bond strength in all groups.

At present, the status of oral and maxillofacial pathology (OMFP) in the country is not properly good. This study aimed to investigate the current status and develop practical approaches to improve occupational condition of the specialty in the future from the viewpoint of the beneficiaries.

This was a descriptive cross‑sectional study. The participants were oral and maxillofacial pathologists of the country (200 individuals), OMFP residents (9 individuals), and final year dental students at six dentistry school of the country at 2020 (200 individuals) through multicenter design. At the first phase, the related questionnaires were developed and assessed psychometrically. Reliability of the questionnaires, internal consistency, and repeatability were computed and confirmed. At the second phase, the survey questionnaires on the current and future condition were sent electronically to the study groups. The data were analyzed using descriptive statistical tests (mean, standard deviation, percentage) and the Pearson test using SPSS.

At the first phase, after primary design of the study too, 23 variables with content validity ratio below 0.56 and content validity index (CVI) below 0.79 were omitted. The questionnaire for the specialists was confirmed with Cronbach’s alpha of 0.75 and intraclass correlation coefficient (ICC) as 0.83, and the questionnaire for the students and the residents were confirmed with Cronbach’s alpha of 0.95 and ICC of 0.80. Results of the second phase showed that score of tendency of students to select OMFP specialty to continue education was 1.58 ± 0.57 from 5. Satisfaction score of specialists on specialized activity of this specialty is 2.7 ± 1.52 from 5. The most important reason for the students to select this specialty was “interest in being faculty member,” and the “difficulty of the specialty” was the most probable reason for not selecting this specialty. The most important priority of the residents was “interest in specialty” and for the specialists was “being faculty member.” The most important reason to change attitude regarding the specialty by the specialists was mentioned as “high occupational and profession responsibility as well as low income” with the score of 1.38 ± 3.99. “Fundamental revision in the educational curriculum of the specialty” with a score of 4.60 ± 0.93 from 5 was considered as the most important revisionary approach from the viewpoint of specialists.

At present, the main problem regarding the OMPF specialty in the country is “high number of graduates and lack of the present occupational opportunities.” Evaluation and validation of the relevant specialized departments, producing occupational opportunities, and fundamental revision in the educational curriculum to train well‑powered specialists are necessary.

Increasing antibiotic resistance to pathogenic microorganisms (Streptococci) has led scientists around the world to turn to medicinal plants. In this study, the effects of aqueous and alcoholic extracts of Zataria multiflora on the in vitro growth of Streptococcus mutans and Streptococcus sanguis have been considered and compared with 0.2% chlorhexidine mouthwash.

In this in vitro study, the inhibitory growth zone was accessed by the disc diffusion method after 48 h of incubation at 37 C. To find out the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of treatments, colony counts of cultured bacteria on nutrient agar have been considered at serial dilution at 1/2‑1/1024 dilution rates. An independent t‑test was used to compare the antibacterial effects of extracts while the level of significance of was considered to be 5% (P < 0.05).

The inhibitory growth zones of aqueous and alcoholic extracts on S. mutans were 26.8 mm and 35.8 mm, respectively, whereas growth zones for S. sanguis were considered as 25.8 mm and 33.2 mm, sequentially. Comparisons showed better effects of alcohol compared to aqueous extract (P > 0.05). The MIC and MBC assessments showed the same results (P > 0.05). In all comparisons, the effects of 0.2% chlorhexidine mouthwash were significantly better than both Z. multiflora aqueous and alcoholic extracts (P > 0.05).

The different solvents may have contributed to the better effects of an alcoholic to aqueous extract of Z. multiflora on the growth of both bacteria. These two extracts could be used for early inhibition of the growth of the planktonic phase, as well as for better oral taste after chlorhexidine applications.

Oral health plays a key role in people’s overall health. Dental caries is the most important problem in children’s oral health. Despite significant advances made in the area of oral health around the world, there is inequality in access to oral health within Iran and abroad, and this is considered a public health challenge. This study was conducted to investigate the access barriers to children’s oral health services from the perspective of parents attending the health centers of Kerman, Iran.

The present descriptive‑analytical study was carried out, as a cross‑sectional survey, on 410 parents of children living in Kerman, Iran. The data were collected by access barriers questionnaire, and then were analyzed by SPSS software using descriptive statistical methods and the multiple linear regression test. Confidence interval (CI) in this study was 95% (95% CI).

The most common access barrier to children’s oral health was the high treatment cost. The access barriers to children’s oral health services were significantly associated with parental education (P = 0.00), maternal employment (P = 0.04), supplementary insurance (P = 0.00), and family income (P = 0.01). Parental satisfaction was also significantly correlated to the child’s sex (P = 0.04), supplementary insurance (P = 0.04), and number of filled teeth (P = 0.04). The mean score of parental satisfaction was 1.83 ± 0.34; within the range of 1–3 from satisfied to dissatisfied.

The cost of dental treatment services high and there are many barriers to accessing children’s oral health.

Emergence of nystatin‑resistant Candida albicans (C. albicans) strains has raised some concerns in the recent years. Recent scientific evidence proves that turmeric, especially curcumin, has anti‑inflammatory and anti‑fungal activity. The aim of this study was the investigation of the antifungal effects of curcumin against nystatin‑resistant C. albicans.

This in vitro, experimental study evaluated standard‑strain (ATCC 16201) and 10 nystatin‑resistant C. albicans strains. The antifungal activity and minimum inhibitory concentration (MIC) of curcumin were evaluated using the CLSI‑M27‑A3, and the MIC of curcumin was compared with that of nystatin. The results were analyzed using the one‑way ANOVA.

The MIC of curcumin was 15.6, 32.25, 15.6, 7.8, 32.25, 15.6, 15.6, 15.6, 32.25, and 15.6 µg/mL for the 10 resistant strains and 62.5 µg/mL for the standard strain of C. albicans. Curcumin in the above‑mentioned concentrations significantly inhibited the proliferation of nystatin‑resistant C. albicans strains (P < 0.001).

According to this research, it was shown that curcumin with MIC value of 7.8–32.25 µg/mL has inhibitory effects on nystatin‑resistant C. albicans strains.

Dentists play an important role in caries prevention by delivering preventive care, educating patients, and buying related products; it is critical to recognize what they know and believe about caries prevention, as well as how they use caries prevention interventions.

A descriptive cross‑sectional study was conducted in South India between January 2021 and February 2021 to determine the dentists’ knowledge, attitude, and practice of prescribing preventive strategies and remineralizing agents for caries prevention. A questionnaire including 11 self‑administered, prestructured questions was made and distributed through electronic media. Chi‑square test was done. The test significance value was taken as 0.05.

A total of 252 dental practitioners participated in the study. The majority of general dentists and specialists followed all the measures such as pit and fissure sealants, fluoride application, counseling patients about oral hygiene maintenance, and regular recall after 6 months to 1 year (P > 0.05). Fluoridated remineralization strategy was found to be the most prescribed (69%) strategy for caries prevention. A significant number of dentists think fluoridated mineralization strategies will remain prevalent (P < 0.05). Younger dentists find practicing preventive dentistry more feasible compared to dentists with greater years of experience (P < 0.05).

Dentists across the country are well aware, have sufficient knowledge, and prescribe preventive strategies such as fluoride application, pit and fissure sealants, regular oral health checkups, and counsel the patients about the importance of oral health but there is a lack of implementation of these preventive strategies in everyday practice.

Marginal fit is a key factor in success of prosthetic restorations. This study aimed to assess and compare the marginal fit of endocrowns fabricated by three‑dimensional (3D) printing and the conventional method.

This in vitro, experimental study evaluated 20 endocrowns, of which 10 were fabricated by 3D printing and 10 were fabricated by the conventional wax‑up technique. The marginal gap was measured at 8 points under a stereomicroscope. The results were analyzed using the Shapiro–Wilk test, paired t‑test, independent t‑test, and one‑way analysis of variance (α = 0.05).

The mean marginal gap was maximum at the distal point, and minimum at the buccal point for the conventionally fabricated endocrowns with an overall mean marginal gap of 99.67 ± 4.59 µm. The mean marginal gap was maximum at the mesiobuccal and minimum at the buccal point before pressing (overall mean of 103.92 ± 2.19 µm) before pressing, and maximum at the distobuccal and minimum at the mesiobuccal point after pressing (overall mean of 117.67 ± 2.87 µm). According to paired t‑test, the mean marginal gap of endocrowns fabricated by 3D printing significantly increased after pressing at all 8 points and also in general, compared with before pressing (P < 0.001). Furthermore, the mean marginal gap at all points was significantly greater in endocrowns fabricated by 3D printing compared with those fabricated by the conventional method (independent t‑test, P < 0.001).

Within the limitations of this in vitro study, the results showed that endocrowns fabricated by the conventional method had significantly superior marginal fit than those fabricated by 3D printing.

In endodontics, glide path creation has been extensively considered a mandatory clinical step to improve the safety and efficiency of rotary nickel–titanium instruments. The high anatomic variations in the mesiobuccal (MB) root of the maxillary molars are observed in the form of canal configuration, number, and position.The aim of this study was to evaluate the negotiability of MB canals in maxillary molars using different pathfiling systems (ProGlider, R‑pilot, HyFlex electrical discharge machining [EDM], WaveOne Gold Glider, and C‑Pilot).

This in vitro study included 125 maxillary first molars with closed apex. Before preparation, all teeth were scanned by periapical radiograph for review of the presence of second MB (MB2) canals, without any resorption or calcification, and moderate curve of MB root canal. Subsequently, the access cavity was prepared with a Diamond Fissure Bur. Then, the samples were divided into five groups (ProGlider, R‑pilot, HyFlex EDM, WaveOne Gold Glider, and C‑Pilot). Certain relevant indices were recorded for analysis, such as the negotiability of the glide path file in the MB canals, file fracture rate, and negotiation speed. The level of significance P value was set at 0.05.

In this study, HyFlex EDM was the only path file that could not reach the full working length (WL) in some cases. The highest frequency of file fracture in the MB2 was observed with HyFlex EDM (24%); nevertheless, R‑Pilot presented an intermediate fracture rate (16%), and both ProGlider and WaveOne Gold Glider were the safest files (4%) in this regard. However, there were no significant differences between the groups (P = 0.065). The lowest and the highest average time of reaching full WL was observed with WaveOne Gold Glider and HyFlex EDM; nonetheless, there was no significant difference between the four rotary groups. The average number of pecks in HyFlex EDM was significantly higher in comparison to those reported for WaveOne Gold Glider and ProGlider.

Path files used for glide path preparation in the MB2 canals of maxillary molars should be flexible with low taper. The use of HyFlex EDM in the MB2 canals is not recommended due to its high taper.

The aim of this study was to investigate and compare the cytotoxicity and gene expression of Bio‑C Repair, Mineral Trioxide Aggregate (MTA) HP Repair, and Biodentine on stem cells derived from exfoliated deciduous teeth.

In this in vitro study MTT assay was used to assess the cellular viability at three different dilutions. The gene expression of Runt‑related transcription factor 2 (Runx2), alkaline phosphatase (ALP), osteocalcin [OCN], and dentin matrix protein‑1 (DMP‑1) was measured with real‑time polymerase chain reaction after 7 days, 14 days, and 21 days of incubation. One‑way analysis of variance and Bonferroni posttest were used for statistical analysis (p=o.o5).

After 72 h of incubation at dilution 1:4, stem cells derived from human exfoliated deciduous teeth (SHEDs) cultivated in Biodentine, followed by Bio‑C Repair and MTA Repair HP reported with highest cellular viability. The highest mRNA expression of Runx2, ALP, OCN, and DMP‑1 was reported in SHEDs cultured in Biodentine (after 21 days of incubation).

Bio‑C Repair and MTA HP Repair are biocompatible and capable of odontogenic differentiation similar to Biodentine when cultured in stem cells derived from exfoliated primary teeth.

Due to the increasing prevalence of oral squamous cell carcinoma (OSCC) in Iran and especially in young people, this study aimed to identify human papillomavirus (HPV) using p16 in OSCC.

In this descriptive‑analytical cross‑sectional study, 40 samples from the archives of the Pathology Department of Kashani Hospital were selected by a definitive diagnosis of OSCC with neck dissection. Demographic information including age, gender, location, and size of the lesion was obtained. Samples were divided into two groups based on lymph node (LN) metastasis. Immunohistochemical staining was performed for p16. Data were entered into SPSS 24 software and statistically analyzed by t‑test, ANOVA, and Spearman nonparametric test. P <0.05 was statistically significant.

The mean age of patients was 59.7 ± 17.11 which in terms of age and gender there was no significant difference between the two groups including with and without cervical LN metastasis (P > 0.05). There was no significant difference between the two groups based on the grade of tumor, perninural invasion, tumor size and location (P > 0.05). The only significant difference between the two groups was based on lymphovascular invasion and disease stage (P < 0.05). The p16 expression also showed a significant difference between the two groups (P < 0.05).

In OSCCs without cervical LN metastasis, a significant increase in p16 expression was observed compared to samples with cervical LNs metastasis. The presence of HPV was higher in samples with less LNs metastasis and possibly a better prognosis.

These days minimally invasive micro‑osteoperforation (MOPs) has accelerated orthodontic tooth movement (OTM). However, there are some conflicting reports about their various impacts; hence, the present systematic review study aimed to evaluate the effect of MOP on root resorption, pulp vitality, and the biological changes of teeth subjected to OTM.

Search in electronic databases of English literature including PubMed, Scopus, Web of sciences, Cochrane, and Google scholar as well as a manual search was performed from 2013 to 2022. Most of the studies included in this article were randomized controlled trials.

From the total number of 321 found articles, 31 duplicated and 268 irrelevant articles were excluded regarding the defined inclusion and exclusion criteria. Consequently, 22 articles were subjected to the quality assessment process, and finally, 18 articles were selected for the review phase. Root resorption during tooth movement using the MOP approach was reported only in one study. Besides, except for two animal studies, all of the relevant included articles showed that MOPs significantly increased the expression of some inflammatory biomarkers known to recruit osteoclast precursors and increase the number of osteoclast cells. On the other hand, two animal studies showed no differences in osteoclast counts by using MOPs in comparison to their control groups, which was consequently the result of biologic variability between animal and human and also probably the small sample sizes of these two studies.

In this systematic review, according to the adverse effects of MOP on root resorption, one study showed higher levels of root resorption among patients undergoing MOP. However, this outcome was due to the different methods used to evaluate the effect of MOPs on root resorption. Moreover, a high certainty of evidence supports that MOP causes biological changes and an elevation in cytokines, chemokines, and other biomarkers that stimulates osteoclasts differentiation which in turn accelerate OTM. There was no change in pulp vitality status based on available evidence.