In vitro effects of antimicrobial properties and shear bond strength of different concentrations of Emodin nanoparticles incorporated orthodontic composites

OBJECTIVE

Fixed appliances used in orthodontic treatment are accompanied by some drawbacks, including the development of white spots or enamel demineralization in the vicinity of the brackets and bonding failures. This study aims to evaluate the effect of combining different wt.% of Emodin nanoparticles (ENPs) with orthodontic adhesives to attain adhesives with improved antimicrobial and mechanical properties.

METHODS

ENPs were synthesized and added to orthodontic composite at different concentrations (0.5%, 1%, and 2%). The distribution of ENPs within the composite was evaluated using a field emission scanning electron microscope (FESEM). A total of 216 disks were prepared, with 144 subjected to an eluted components test, 36 used for disk agar diffusion (DAD) test, and 36 for biofilm inhibition test. These tests aimed to assess the antimicrobial activity of the composites against Streptococcus mutans, Lactobacillus acidophilus, and Candida albicans. Additionally, the bond strength between stainless-steel brackets and teeth was evaluated using the shear bond strength (SBS) test, and the adhesive remnant index (ARI) score was determined. One-way analysis of variance and Kruskal-Wallis test were used to analyse the SBS and ARI, respectively. For pairwise group comparison concerning the biofilm inhibition, DAD, and eluted components tests, the Tamhane and Games-Howell tests for data with unequal variances and the post-hoc Tukey's HSD and Scheffe tests for data with equal variances were used.

RESULTS

The FESEM results confirmed the synthesis and even distribution of ENPs in the composite. Only the 2% group showed significant biofilm inhibition against all microorganisms studied (P<0.05). The DAD test revealed that a 1% concentration of ENPs is sufficient to inhibit growth for all microorganisms. The eluted components test demonstrated that the 2% concentration of ENPs performed significantly better against S. mutans compared to the control group (P<0.05). The highest mean SBS was observed with the 0.5% ENP concentration, while no significant differences in SBS and ARI were found among the groups (P>0.05).

CONCLUSIONS

This in vitro study showed that the 2% concentration of ENP produced significantly improved antimicrobial activity without adversely affecting SBS and ARI score. This would support the addition of 2% ENP to orthodontic adhesives.

An evaluation of photobiomodulation effects on human gingival fibroblast cells under hyperglycemic condition: an in vitro study

An in vitro study was designed to evaluate the effects of photobiomodulation (PBM) with 915-nm diode laser on human gingival fibroblast (HGF) cells under hyperglycemic condition. The HGF cells were cultured in Dulbecco's modified eagle medium (DMEM) medium containing 30 mM glucose concentration for 48 h to mimic the hyperglycemic condition. Subsequently, the cells received three sessions of PBM (915 nm, continuous emission mode, 200 mW, energy density values of 3.2, 6, and 9.2 J/cm2). Twenty-four hours post-irradiation, cell proliferation, expression of interleukin 6 (IL-6), and vascular endothelial growth factor (VEGF) were assessed with MTT and real-time polymerase chain reaction (PCR) tests, respectively. Also, reactive oxygen species (ROS) production was measured using CM-H2DCFDA fluorimetry. No changes were detected in the cell proliferation rate between the high glucose control group and laser-treated cells, while VEGF and IL-6 gene expression levels increased significantly after PBM in the high glucose-treated cells group. ROS level was significantly decreased in the irradiated cells in high-glucose medium compared with the high glucose control group. Our study revealed the inductive role of 915-nm-mediated PBM on VEGF and the inflammatory response while concurrently reducing reactive oxygen species production in HGF cells in hyperglycemic conditions.

Effect of hydroalcoholic extract of whole pomegranate fruit on cariogenic bacteria and its clinical effect on dental plaque formation in 8-10-year-old children

Background

This study aimed to assess the effect of hydroalcoholic extract of the whole pomegranate fruit on Streptococcus mutans (S. mutans) and Lactobacillus acidophilus (L. acidophilus) and its clinical effect on dental plaque formation in 8-10-year-old children.

Materials and Methods

This study was conducted in two phases of in vitro and clinical trial. In the in vitro phase, the antibacterial effect of 50%-50% hydroalcoholic extract of whole pomegranate fruit on S. mutans and L. acidophilus was assessed by the disc diffusion test. In the double-blind cross-over clinical trial phase, 14 children between 8 and 10 years were randomly assigned to two groups of 38% pomegranate mouthwash and 0.12% chlorhexidine (CHX) after assessing their baseline dental plaque by oral hygiene index-simplified (OHI-S). The children were asked not to use any other plaque control measure during the study. Their OHI-S score was measured again after 5 and 14 days using disclosing tablets. Data were analyzed by t-test and paired t-test at 0.05 level of significance.

Results

The hydroalcoholic extract of pomegranate showed a positive antibacterial effect on S. mutans and L. acidophilus. However, its inhibitory effect was significantly lower than that of 0.12% CHX (P < 0.05). None of the tested mouthwashes inhibited plaque formation, but pomegranate mouthwash and CHX decreased the OHI-S score by 34% and 36%, respectively (P < 0.05), with no significant difference between them (P > 0.05).

Conclusion

The whole pomegranate fruit hydroalcoholic extract showed significant inhibitory effects on S. mutans and L. acidophilus. Furthermore, 38% pomegranate mouthwash had a comparable efficacy to CHX in the reduction of dental plaque.

Dos and don'ts in designing a computerized oral and lip squamous cell cancer registry

BACKGROUND

In the last ten years, many countries have started to develop constructive systems for registering common diseases and cancers. In this research, we intended to determine and identify the minimum data set (MDS) required for the design of the oral and lip squamous cell cancer registration system in Iran.

METHODS AND MATERIAL

At first, primary information elements related to disease registries were extracted using scientific papers published in reliable databases. After reviewing the books, related main guidelines, and 42 valid articles, the initial draft of a researcher-made questionnaire was compiled. To validate the questionnaire, two focus group meetings were held with 29 expert panel members. The final version of this questionnaire was prepared by extracting different questions and categories and receiving numerous pieces of feedback from specialists. Lastly, a final survey was conducted by the experts who were present at the previous stage.

RESULTS

Out of 29 experts participating in the study, 17 (58.62%) were men and 12 (40.37%) were women. The age range of experts varies from 34 to 58 years. One hundred-fourteen items, which are divided into ten main parts, were considered the main information elements of the registry design. The main minimum data sets have pertained to the demographic and clinical information of the patient, information related to the consumed drugs, initial diagnostic evaluations of the patient, biopsy, tumor staging at the time of diagnosis, clinical characteristics of the tumor, surgery, histopathological characteristics of the tumor, pathologic stage classification, radiotherapy details, follow-up information, and disease registry capabilities. The distinctive characteristics of the oral and lip squamous cell cancer registry systems, such as the title of the disease registration programme, the population being studied, the geographic extent of the registration, its primary goals, the definition of the condition, the technique of diagnosis, and the kind of registration, are all included in a model.

CONCLUSION

The benefits of designing and implementing disease registries can include timely access to medical records, registration of information related to patient care and follow-up of patients, the existence of standard forms and the existence of standard information elements, and the existence of an integrated information system at the country level.

The effect of preparation design on the fracture resistance and adaptation of the CEREC ceramic endocrowns

OBJECTIVE

The purpose of this experimental in vitro study was to assess the effect of having one or two intact axial walls on the improvement of the fracture resistance, and marginal and internal adaptation of computer-aided design/computer-aided manufacturer fabricated ceramic endocrowns.

MATERIALS AND METHODS

Thirty-six endodontically treated mandibular molars were divided into three groups (n = 12). Group A, represented teeth that all of their axial walls were reduced till they all had 3 mm height. In group B, the buccal wall had 5 mm height and the others were reduced to 3 mm. Specimens of the group C had 5-mm-height buccal and one 5 mm-height proximal wall, with all other walls of 3 mm height. All teeth were scanned using intraoral scanner, and endocrowns were milled from zirconia lithium silicate ceramics blocks. The marginal and internal discrepancy of restorations were evaluated with the replica technique. Fracture resistance was also measured after cementation and modes of failure were observed. One-way analysis of variance and Tukey HSD multiple comparisons were used to analyze the data (α = .5).

RESULTS

Significant differences were observed within the groups in terms of the axial discrepancy (p = .022); group A had significantly higher amounts of axial discrepancy compared to group B (p = .001) and group C (p = .003). Preservation of the intact axial walls did not result in a statistically significant decrease in marginal (p = .21) and pulpal (p = .31) discrepancy values. Also, concerning the fracture resistance no significant difference was observed among the groups (p = .51).

CONCLUSION

Preservation of at least one of the axial walls could reduce the amount of the axial discrepancy and, therefore, improves the adaptation of the restoration. However, based on this study, it did not improve fracture resistance.

Comparison of the 1 and 2% pilocarpine mouthwash in a xerostomic population: a randomized clinical trial

AIMS & BACKGROUND

Pilocarpine is an accepted treatment for xerostomia, but limited research has been conducted on the oral, topical form. The present study aimed to compare the effects of 1 and 2% pilocarpine mouthwash on xerostomic participants.

METHODS

In this double-blind clinical trial study, 48 subjects with xerostomia were randomly divided into three groups to measure the effects of 1 and 2% pilocarpine and placebo mouthwashes on saliva levels. The amount of saliva in the 1st and 14th days was measured at 0, 45, 60, and 75 mins, while participants used their mouthwash three times a day for 14 days. On the 1st and 14th days, they filled out the information forms on xerostomia and the medicine's side effects before and after the intervention.

RESULTS

On the 1st day, the mean salivary flow at 45, 60, and 75 mins in the 2 and 1% pilocarpine mouthwash were significantly higher than in the placebo mouthwash group (p < 0.05). On the 14th day, the mean salivary flow time at 45 mins in the 2% pilocarpine mouthwash group was significantly higher than in the placebo mouthwash group (p = 0.007). Furthermore, the mean salivary flow at 60 and 75 mins in the 2% (p < 0.001) and 1% pilocarpine mouthwash (p = 0.028) was significantly higher than in the placebo group. Moreover, the salivary flow in the 2% pilocarpine mouthwash group was significantly higher than the 1% pilocarpine mouthwash (p < 0.05) during these two times. No side effects were observed in any of the subjects.

CONCLUSIONS

The study showed that 5 ml of 2 and 1% pilocarpine mouthwash for 2 weeks increased salivary flow in xerostomic participants compared to placebo without any side effects.

Effect of Hemostatic Agents on Shear Bond Strength of Orthodontic Eyelets Bonded with Conventional and Self-etch Adhesives

Statement of the Problem

The risk of debonding of the orthodontic eyelets due to blood contamination from the impacted tooth is a clinical problem that orthodontists face routinely.

Purpose

This study aimed to assess the effect of hemostatic agents (Viscostat clear and Astringedent X) on shear bond strength (SBS) of orthodontic eyelets bonded with conventional (Transbond XT) and universal adhesive (GC-G Premio bond) adhesives.

Materials and Method

In this experimental study, 84 freshly extracted bovine lower incisors were randomly divided into 7 groups namely TBXT, Blood, SEP, VISCO + TBXT, VISCO + SEP, ASTX + TBXT, and ASTX + SEP groups. In the TBXT group, teeth were etched with phosphoric acid gel, and then, the Transbond XT primer was applied and eyelets were bonded with Transbond XT. In the blood group, first, contamination with blood was done followed by the same procedure as TBXT. In other groups, the teeth were etched with phosphoric acid and based on their group allocation, Transbond XT primer (in TBXT groups), GC-G Premio Bond (in SEP groups), ViscoStat Clear gel (in VISCO groups), or Astringedent X (in ASTX groups) were applied. The SBS was measured for each group and the adhesive remnant index (ARI) was determined.

Results

The mean SBS was 20.79 MPa in VISCO+SEP group, 19.2 MPa in the TBXT group, 16.06 MPa in the SEP group, 15.43 MPa in VISCO+TBXT group, 9.39 MPa in AST-X+TBXT group, and 1.62 MPa in the blood group. The SBS of ASTX+SEP, blood and TBXT+ASTX groups had significant differences from the SBS of the control group (p< 0.05). The ARI score of 0 had the highest frequency in the blood group.

Conclusion

Due to the high coagulative effect of Astringedent X and acceptable SBS of Astringedent X in combination with GC-G Premio bond, this combination can be recommended for exposure of impacted teeth that are at high risk of blood contamination.

Investigating the Relationship between Fingerprint Pattern and Development of Oral Squamous Cell Carcinoma

STATEMENT OF THE PROBLEM

Oral squamous cell carcinoma (OSCC) constitutes more than 90% of oral malignancies. The main risk factors of OSCC include cigarette smoking and alcohol. However, since not all smokers or alcohol drinkers develop this disease, other factors have also been suggested including genetic characteristics of every person to be implicated in the probability of developing OSCC.

PURPOSE

Our aim in this study is to investigate the possible relationship between fingerprint patterns and the probability of developing OSCC.

MATERIALS AND METHOD

In a cross sectional study, we had 140 patients in 2 groups as OSCC and cancer free. Fingerprints were recorded by fingerprint scanner device. The fingerprint patterns were categorized into three major groups and four subgroups. Groups were tested by chi-square.

RESULTS

The relationship between the main fingerprint patterns and incidence of OSCC became significant (p= 0.037). The frequency of the main pattern of Arch was significantly higher in the experimental group than in the control group (p< 0.05). Considering the main patterns of Loop and Whorl, no significant difference existed between the two groups. Furthermore, the frequency of subtype patterns of Double Whorl and Central Pocket Whorl was significantly higher in the control group than in the experimental group (p< 0.05).

CONCLUSION

Since dermatoglyphics is contingent upon genetic variations, fingerprint can be used for investigating the susceptibility of people in developing different diseases, though further studies are required in this regard. This method is in no way a substitute for gold standard methods for diagnosis.

Self-declarative Performance of General Dentists in Prescribing Analgesics and Antibiotics for Patients Requiring Root Canal Treatment

Objectives: This study aimed to determine the self-declarative performance of general dentists in prescription of analgesics and antibiotics for patients requiring root canal treatment (RCT).

Materials and Methods: In this cross-sectional study, 400 general dentists participating in the 55^th International Annual Scientific Congress of the Iranian Dental Association (2015) were randomly selected, and requested to complete a questionnaire about their performance regarding prescribing analgesics and antibiotics for patients requiring RCT. The frequency and percentage of answers to each question were calculated and reported.

Results: The most commonly prescribed analgesics included ibuprofen (100.0%), Gelofen (100.0%), Novafen (68.5%) and acetaminophen (24.8%). After RCT, dentists prescribed ibuprofen (100.0%), Gelofen (98.3%), dexamethasone (35.3%), Novafen (27.3%) and acetaminophen/codeine (15.8%) in decreasing order of frequency. Antibiotic prescription was minimum (48.5%) for cases with painful (moderate or severe) irreversible pulpitis (vital tooth) before the treatment and maximum for cases of pulp necrosis with acute apical periodontitis, edema, and preoperative symptoms (moderate or severe) (97.3%). For non-allergic patients, the most frequently prescribed antibiotics were amoxicillin 500 mg (93.3%), cefixime 400 mg (81.3%), amoxicillin/metronidazole 250 mg (71.8%), co-amoxiclav 265 mg (36.3%) and injectable penicillin (0.5%). For allergic patients, dentists prescribed clindamycin 300 mg (84.0%), cephalexin 500 mg (15.8%), azithromycin 500 mg (13.5%), and erythromycin 500 mg (10.8%). Sex and graduation date had no significant effect on the results (P>0.05).

Conclusion: Antibiotic prescription is excessive by general dentists, and their performance regarding the proper and logical prescription of antibiotics in RCT should be improved.

Comparison of diagnostic effects of infrared imaging and bitewing radiography in proximal caries of permanent teeth

This study aimed to compare the diagnostic efficacy of VistaCam iX intraoral camera system using infrared light and bitewing radiography for detection of proximal caries in permanent teeth. This in vitro study was performed on 108 teeth. The proximal surfaces of the teeth were examined for caries using ICDAS II criteria, bitewing radiography, and the Proxi head of VistaCam iX. The teeth were then sectioned and histologically analyzed (gold standard). Data were analyzed using SPSS version 25 via the correlation test at P < 0.05 level of significance. The overall and segmental sensitivity and specificity values were calculated for (1) the contact area and higher regions, (2) below the contact area to the cementoenamel junction (CEJ), and (3) below the CEJ. Radiography had the highest specificity. VistaCam had the highest overall and segmental sensitivity for enamel caries. Radiography had the highest segmental sensitivity for dentin. In region 1, VistaCam had the highest sensitivity and lowest specificity, and radiography and ICDAS II had the highest specificity and lowest sensitivity. In region 2, radiography showed the highest sensitivity and specificity. VistaCam had the lowest sensitivity and ICDAS II had the lowest specificity in this region. In region 3, VistaCam did not detect any caries and radiography had a better performance than ICDAS II. The specificity value was equal for both methods. VistaCam had the highest diagnostic efficacy among the three methods for caries in region 1; however, bitewing radiography had a superior efficacy in regions 2 and 3.

Diagnosis of Approximal Caries after Delayed Scanning of Photostimulable Phosphor Plates

STATEMENT OF THE PROBLEM

Considering the high diagnostic accuracy and wide dynamic range of photostimulable phosphor plates (PSPs), they can be a good alternative for radiographic films.

PURPOSE

This study was aimed to assess the effects of delay in scanning PSPs on the diagnostic accuracy of detection of approximal caries.

MATERIALS AND METHOD

Radiographs from fifty-two extracted molar and premolar teeth were radiographed using DIGORA PSP (Soredex Corporation, Helsinki, Finland). The teeth were either intact or with non-cavitated approximal caries. The plates were scanned immediately (time zero) and at 10 min, 30 min, 60 min and 120 min after exposure. Sixty-five images were obtained and evaluated for presence or absence of approximal caries by two oral and maxillofacial radiologists and 2 restorative specialists. The diagnostic accuracy of approximal caries detection was measured using a 5-point rating scale. Definite presence of caries was confirmed using a stereomicroscope. Analysis of caries detection data was performed by calculating sensitivity and specificity using repeated measures with ANOVA.

RESULTS

Significant differences were found in complete negative predictive value, absolute negative predictive value and complete dentine sensitivity value between different scan times (p< 0.05). These values were significantly different at 10 min, 60 min and 120 min (p< 0.05). However, immediate scan and 30 min delay were not significantly different (p> 0.05). The accuracy of approximal caries detection at 120 min was less than at 60 min and at 60 min was less than at 30 min.

CONCLUSION

In order to detect approximal caries more accurately, DIGORA PSPs should be scanned within 30 min after exposure.

Effect of Two Polishing Systems on Surface Roughness, Topography, and Flexural Strength of a Monolithic Lithium Disilicate Ceramic

PURPOSE

To evaluate the effect of overglazing and two polishing procedures on flexural strength and quality and quantity of surface roughness of a monolithic lithium disilicate ceramic computer-aided design (CAD) after grinding.

MATERIALS AND METHODS

This in vitro study was conducted on 52 partially crystalized bar-shaped specimens (16 × 4 × 1.6 mm) of monolithic lithium disilicate ceramic. The specimens were wet polished with 600-, 800-, and 1200-grit silicon carbide papers for 15 seconds using a grinding/polishing machine at a speed of 300 rpm. Then, the specimens were crystalized and glaze-fired in one step simultaneously and randomly divided into four groups of 13: (I) Glazing group (control); (II) Grinding-glazing group, subjected to grinding with red band finishing diamond bur (46 μm) followed by glazing; (III) Grinding-D+Z group, subjected to grinding and then polishing by coarse, medium, and fine diamond rubber points (D+Z); and (IV) Grinding-OptraFine group, subjected to grinding and then polishing with a two-step diamond rubber polishing system followed by a final polishing step with an OptraFine HP brush and diamond polishing paste. The surface roughness (Ra and Rz) values (μm) were measured by a profilometer, and the mean values were compared using one-way ANOVA and Tamhane's test (post hoc comparison). One specimen of each group was evaluated under a scanning electron microscope (SEM) for surface topography. The three-point flexural strength values of the bars were measured using a universal testing machine at a 0.5 mm/min crosshead speed and recorded. The data were analyzed using one-way ANOVA and Tamhane's test (α = 0.05).

RESULTS

Statistically significant differences were noted among the experimental groups for Ra, Rz (p < 0.0001), and flexural strength values (p < 0.009). The lowest Ra and Rz values were found in the grinding-OptraFine group (0.465 ± 0.153), which were significantly lower than those in glazing (p < 0.03) and grinding-glazing (p < 0.001) groups. The Ra and Rz values were not significantly different between the two polishing systems (p = 0.23 and p = 0.25, respectively). The highest flexural strength was found in the glazing group (283.350 ± 49.854 MPa) without significant differences compared to grinding-glazing (p = 0.98) and grinding-OptraFine groups (p = 0.86). The lowest flexural strength was found in grinding-D+Z group (225.070 ± 17.299), which was significantly different from the value in glazing (p < 0.03) and grinding-glazing (p < 0.04) groups. SEM analysis of polished surfaces revealed regular morphology with some striations.

CONCLUSIONS

The OptraFine system created smoother and more uniform surfaces in terms of quantity (p < 0.03 for Ra, p < 0.01 for Rz) and quality of roughness compared to glazing. The flexural strength of lithium disilicate ceramic after polishing with the OptraFine system was similar to that after glazing (p = 0.86). Despite similar surface roughness after polishing with the two systems, the D+Z system reduced the flexural strength of ceramic (p < 0.03).

Perception of Laypeople and Dental Professionals of Smile Esthetics

OBJECTIVES

This study aimed to assess and compare the perception of laypersons and dental professionals of smile esthetics based on two factors namely gingival display and alignment of teeth.

MATERIALS AND METHODS

A total of 32 females were randomly selected among dental students in the International Campus of School of Dentistry, Tehran University of Medical Sciences (Tehran, Iran) with no previous history of esthetic dental work. Frontal photographs were obtained and cropped from the subnasal to menton areas of subjects to standardize the size of pictures. Three series of slides were prepared of the pictures using Microsoft PowerPoint software. The first series of slides were shown to familiarize the observers with the images. The second and third series were displayed for the observers and they were then asked to fill out a questionnaire. The group of observers included 10 dental specialists and 10 laypersons. Each observer was given a visual analog scale (VAS) chart for scoring (1-10). After completion of the questionnaires, data were transferred to a computer and the differences in judgments of professionals and laypeople were analyzed using the Mann Whitney test.

RESULTS

No significant difference was found in the judgments of professionals and laypeople on evaluating overall smile esthetics, gingival display and alignment of teeth except for the slide showing a reverse smile arc.

CONCLUSIONS

Laypeople and professionals had similar perceptions of smile esthetics. Thus, it appears that clinicians can rely on the judgment of laypersons in esthetic dental treatments.

An In Vitro Comparison of Antimicrobial Effects of Curcumin-Based Photodynamic Therapy and Chlorhexidine, on Aggregatibacter actinomycetemcomitans

INTRODUCTION

Considering the importance of prevention in periodontal diseases and the important role of Aggregatibacter actinomycetemcomitans in induction and progression of these diseases, the aim of the present in vitro study was to compare the antimicrobial effects of chlorhexidine digluconate (CHX), curcumin and light-emitting diode (LED) laser, on this bacterium.

METHODS

Antimicrobial activity of curcumin (5 mg/ml), CHX (2%), LED (120 J/cm(2)) and LED + curcumin (120 J/cm(2) + 2.5 mg/ml) against A. actinomycetemcomitans were tested in vitro, using micro-broth dilution test. One-way analysis of variance (ANOVA) and Tukey's HSD tests served for statistical analysis.

RESULTS

Regarding the minimum inhibitory concentration (MIC), CHX had a significantly lower MIC than curcumin (P < 0.05). Sorted out by bacterial growth from lowest to highest, were CHX, LED + curcumin, curcumin, and LED groups. All the differences were found to be statistically significant (P < 0.05) except for the LED group.

CONCLUSION

We conclude that curcumin is an effective substance in preventing the growth of A. actinomycetemcomitans, whose impact is reinforced when used simultaneously with photodynamic therapy (PDT).

Effect of 30% hydrogen peroxide on marginal integrity of silorane-based versus methacrylate-based composite restorations

OBJECTIVES

The aim of this study was to assess the effect of 30% hydrogen peroxide on the microleakage of class V cavities restored with either a silorane-based composite or two methacrylate-based composites.

MATERIALS AND METHODS

A total of 96 standard class V cavities (1.5 × 2 × 3 mm) were prepared on the buccal surface of sound extracted human premolars with both enamel and dentin margins and randomly assigned into three groups of Filtek P90 (group A) with its respective bonding (P90 system adhesive), Filtek Z250 (group B) and Filtek Z350XT (group C), both with Adper Prompt L-Pop bonding. The teeth were subjected to thermocycling (1000×, 5-55ºC) and half of them randomly underwent bleaching (30% hydrogen peroxide, 15 min, three times), while the remaining half (control) were not bleached. Dye penetration was measured following immersion in 2% basic fuchsin for 24 h. Data were statistically analyzed using Kruskal-Wallis and Mann-Whitney U tests at 95% CI.

RESULTS

No significant differences were found between the composites in the control groups in enamel (P=0.171) or dentin (P=0.094) margins. After bleaching, microleakage of Z250 (at the occlusal (P=0.696) or gingival (P=0.867) margins), Z350 (at the occlusal (P=0.323) margin) and P90 (at the occlusal (P=0.316) or gingival (P=0.281) margins) did not change significantly.

CONCLUSION

No significant differences were noted between the bleached and control subgroups of Z250 and P90 in enamel or dentin margins. Microleakage of Z350 composite was reduced at the gingival margin compared to the control group, but no significant difference was observed at the occlusal margin. Microleakage of silorane-based composite in gingival margin was significantly more than two metacrylate-based composites.

The effect of hydro alcoholic extract of seven plants on cariogenic bacteria--an in vitro evaluation

AIM

To compare the antibacterial effect of hydro alcoholic extract of Salvia officinalis, Pimpinella anisum, Satureja hortensis, Rhus coriaria, Carum copticum, Mentha longifolia, Achillea millefolium against Streptococcus mutans, Lactobacillus rhamnosus and Actinomyces viscosus through two in vitro methods.

METHODS

In this experimental study, hydro-alcoholic extracts have been prepared from the shoot of Salvia officinalis, Satureja hortensis, Mentha longifolia and Achillea millefolium, the seed of Pimpinella anisum and Carum copticum and the fruit of Rhus coriaria with maceration method. Their antibacterial activity against Streptococcus mutans, Lactobacillus rhamnosus and Actinomyces viscosus have been evaluated with broth macrodilution and agar diffusion methods.

RESULTS

In Broth macrodilution method MIC (Minimum Inhibitory Concentration) of Pimpinella anisum, Salvia officinalis, Mentha longifolia, Achillea millefolium, Satureja hortensis, Carum copticum and Rhus coriaria for Streptococcus mutans were respectively 12.5, 6.25, 12.5, 50, 50, 12.5 and 50 μg/ml, for Lactobacillus rhamnosus 12.5, 1.56, 3.12, 12.5, 6.25, 6.25 and 6.25 μg/ml and for Actinomyces viscosus 50, 12.5, 100, 50, 100, 25 and 25 μg/ml. In Agar diffusion method Pimpinella anisum, Salvia officinalis and Rhus coriaria against Streptococcus mutans, Pimpinella anisum, Carum copticum and Rhus coriaria against Lactobacillus rhamnosus and Mentha longifolia, Rhus coriaria and Carum copticum against Actinomyces viscosus had antibacterial effects.

CONCLUSION

All seven extracts had growth inhibitory effects on all three bacteria. Salvia officinalis had the greatest inhibitory effect on growth of all three bacteria. All of the extracts except Carum copticum had bactericidal effect in the range of concentration. By agar diffusion method Rhus coriaria had antibacterial effect against all three cariogenic bacteria.

Effects of 15% carbamide peroxide and 40% hydrogen peroxide on the microhardness and color change of composite resins

OBJECTIVE

The aim of this study was to determine the effects of 40% hydrogen peroxide and 15% carbamide peroxide on microhardness and color change of a silorane-based composite resin in comparison with two methacrylate-based composites.

MATERIALS AND METHODS

Fifty-four disc-shaped specimens (A3 shade) were fabricated of Filtek P90 (P90), Filtek Z350XT Enamel (Z350) and Filtek Z250 (Z250) (3MESPE) (n=18). The samples of each composite were randomly divided into three subgroups of 6. The control subgroups were immersed in distilled water; the test groups were exposed to Opalescence Boost (OB) once; and Opalescence PF (OP) (Ultradent) for two weeks. Vickers microhardness testing and a spectrophotometric analysis of the color of samples were performed before and after each intervention.

RESULTS

The baseline microhardness of P90 was significantly lower than that of the other two composites (P=0.001), but no difference was found between Z250 and Z350 in this respect (P=0.293). Bleaching treatments significantly decreased the microhardness of Z250 and Z350 (P< 0.001), but no change was observed in P90 test and control subgroups (P> 0.05). No significant difference was detected between the two types of bleaching (P>0.05). After bleaching with OB, ΔE value was measured to be 3.12(1.97), 3.31(1.84) and 3.7(2.11) for P90, Z250 and Z350, respectively. These values were 5.98(2.42), 4.66(2.85) and 4.90(2.78) after bleaching with OP with no significant difference.

CONCLUSION

Bleaching decreased the microhardness of methacrylate-based but not silorane-based composites. Although no significant differences were found in ΔE of composites, ΔE of all groups did not remain in the clinically acceptable range after bleaching except for P90 after bleaching with 40% H2O2 (ΔE < 3.3).

Mast cells density in fibrotic capsule of enchondroma and well-differentiated chondrosarcoma: a method for histopathologic differentiation

BACKGROUND

An enchondroma is a benign and a well-differentiated chondrosarcoma is an invasive chondroid tumor with high recurrence potential. In spite of biologic differences, these two tumors have very similar histopathologic appearance. It has been shown that the biologic nature of the connective tissue around benign and malignant tumors varies in the number of mast cells. The aim of this study was to study the histopathologic distinction of enchondroma and well-differentiated chondrosarcoma using the density of the mast cells in fibrotic capsule.

METHODS

Twelve enchondroma and 15 well-differentiated chondrosarcoma were collected from Pathology department of Cancer Institute and Central Pathology department of Imam Khomeini Hospital in Tehran. 3 micron paraffin embedded tissue sections were stained by toluidine blue for mast cells counting. Mast cells were counted in fibrous capsule of all cases. Mast cells counts were accomplished in 10 high power fields. The average number of mast cells in 10HPF was determined as an index for each lesion. Mann-Whitney U test was used for statistical analysis.

RESULTS

Mean index in enchondroma and well-differentiated chondrosarcoma groups were 0.1±0.12 and 0.31±0.33 respectively, showing a significant difference between number of mast cells in the fibrotic capsule in these two lesions (p = 0.028). Comparison of the corresponding points in ROC curve, showed a cut-off point = 0.15, with positive predictive value of 61%, negative predictive value 71%, specificity of 33.3% and sensitivity of 66.7%, (p = 0.025).

CONCLUSION

Average density of the mast cells in the surrounding fibrotic capsules of enchondroma and well-differentiated chondrosarcoma along with other criterions, could be a beneficial factor for histologically differentiation between these two lesions.