Combination effects of diode laser and resin-modified tricalcium silicate on direct pulp capping treatment of caries exposures in permanent teeth: a randomized clinical trial.

OBJECTIVE: The purpose of this randomized clinical trial was to evaluate efficiency of diode 808-nm (Picasso-AMD, USA) laser using power 1.5 W, continuous wave (CW), fiber diameter of 400 µm, non-initiated and in contact mode, tip angle set at 90°, beam divergence 16°, 2 s per an area with 1-mm diameter, power density 190.98 W/cm2, energy density 381.97 J/cm2, vertical and horizontal scanning movement on the exposure site, and laser irradiation combined with a resin-based tricalcium silicate material (TheraCal LC, Bisco, USA) in direct pulp capping in caries exposures of permanent teeth over a period of 6 months. MATERIAL AND METHODS: In this randomized clinical trial, a total of 20 anterior and posterior vital teeth without symptoms and radiographic changes of 14 patients between the age group of 15-35 years, of which randomly 10 teeth were considered, each for TheraCal LC, the exposed area was sealed with TheraCal paste and TheraCal combined with diode laser; the treated area was sealed with TheraCal paste after diode 808-nm laser irradiation. At the 1-, 3-, and 6-month recall examinations, the loss of vitality, spontaneous pain, reactions to thermal stimuli and percussion, and radiographic changes were considered failure. The samples were randomly divided using runs test. Measurements on the digitized radiograph were performed at the recalls. The data were analyzed by repeated measurements ANOVA using SPSS 25. RESULTS: Analysis had indicated that at the end of follow-ups, a statistically significant increase in dentin thickness with both groups (p value < 0.001) was found. Clinically, diode laser group has shown better results (p value < 0.001); however, radiographically, no significant difference was observed between groups (p value = 0.56). In both groups, the highest thickness of dentin formed was at the first month; 0.40 mm ± 0.19 mm (p value < 0.001). CONCLUSION: Diode laser 808 nm under proper parameters combined with TheraCal LC can be recommended for direct pulp therapy in caries exposure of permanent teeth. CLINICAL TRIAL REGISTRATION: This research was approved by Esfahan Medical University, Dental School, Azad Branch (KHUISF)) Esfahan, Iran [IR.IAU.KHUISF.REC.1397.261].

Influence of Hand Instrumentation and Ultrasonic Scaling on the Microleakage of various Cervical Restorations: An in vitro Study.

INTRODUCTION: In cervical lesions, various restorative materials can be inserted, which can be affected by the application of periodontal scalers. This study evaluated and compared the marginal seal of class V glass ionomer, composite resin, and amalgam restorations after subjecting them to hand instrumentation and ultrasonic scaling. MATERIALS AND METHODS: In this experimental study, 30 sound human first premolars were selected. In each tooth, buccal and lingual cavities (4 mm mesiodistal width, 3 mm occlusogingival height, and 2 mm depth) were made. The teeth were randomly assigned to three groups of 10 teeth: (1) Glass ionomer group, (2) composite group, and (3) amalgam group. Teeth were subjected to thermocycling procedure for 1,000 cycles between 5 and 55°C water baths and a 1-minute dwell time. Then, each group was randomly subdivided: (1) Margins of 30 restorations were exposed to hand instrumentation procedures by applying 10 working strokes, (2) margins of 30 restorations were exposed to a periodontal tip mounted on a piezoelectric ultrasonic handpiece working at 25 kHz for 10 seconds. The specimens were serially sectioned mesiodistally. Each section was examined under a stereomicroscope. The extent of microleakage was ranked using a 0 to 4 scale at both occlusal and cervical margins of the restorations. Data were analyzed initially using the Kruskal-Wallis test, followed by multiple comparisons using the Mann-Whitney and Wilcoxon test. RESULTS: The type of restorative material had a significant influence on dye penetration, whether in the enamel margin or in the dentinal margin (p < 0.001). The microleakage of glass ionomer group was the highest. No statistical differences were found in dye penetration between scaling groups (hand instrumentation and ultrasonic scaling) (p > 0.05). CONCLUSION: Type of restorative material had a significant influence on microleakage. No statistical differences were found in dye penetration between scaling groups. CLINICAL SIGNIFICANCE: The microleakage of glass ionomer restoration is greater than amalgam and composite restorations after subjecting them to hand instrumentation and ultrasonic scaling.

Penetration and durability of CPP-ACP paste and sodium fluoride varnish as desensitizing agents: An in vitro comparison.

Background: This study aimed to investigate and compare the penetration and durability of two dentin desensitizers, sodium fluoride varnish and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste, using electron microscopy. Methods: The study was performed on 60 dentin specimens prepared from extracted human premolars. After applying 17% EDTA to remove the smear layer, the specimens were divided into two groups. MI Paste and Bi-fluoride varnish were applied to the specimens. Microscopic images of 20 samples were obtained immediately. Twenty other samples were accessed after 15 days, and the other 20 were accessed after 30 days of toothbrushing and thermal cycling. Both surface and longitudinal cross-sectional images (after sample fracture) were studied. Data were analyzed with two-way ANOVA and Mann-Whitney U test at a significance level of P<0.05. Results: The mean depth of material penetration was significantly time-dependent and fluctuated in both groups. There was a significant difference between the mean level of plugs between 0, 15, and 30 days (P<0.001). Penetration increased with time for the MI Paste group, while in the Bi-fluoride group, the increase was significant at 15 and 30 days than immediately after application. The mean thickness of the plugs was significantly different at the three time periods, and MI Paste showed a sudden decrease in plug thickness after 15 days. Conclusion: Immediately after application, Bi-fluoride occluded dentinal tubules more effectively, and its durability after abrasion and thermal fatigue were higher than MI Paste.

Comparison of microleakage of composite restorations using fifth and sixth generation dentin bonding agent: an in vivo study.

INTRODUCTION: The success of bonded restorations depends on effective bonding between restorative materials and tooth structure, and it prevents microleakage. New dentin bonding systems have been introduced which promotes this concept. The aim of this study was to compare the amount of microleakage between 'single bond' vs 'Prompt L-Pop' during different time periods. MATERIALS AND METHODS: In this clinical trial study, 60 nonretentive class five cavities were prepared on buccal surfaces of human premolars which were scheduled to be removed for orthodontic purposes. The cavities were restored using two different bonding agents; fifth generation (Single Bond) and sixth generation (Prompt L-Pop) and then filled with resin composite (Filtek Z-250). The samples in both groups were extracted after placing the restoration in three periods of time: Immediately, 1 week and 6 months postplacement. Specimens were sealed with two layers of nail varnish except for 1 mm around restoration and immersed in a silver nitrate solution for 24 hours. The teeth were then sectioned longitudinally and the degree of microleakage was determined by stereomicroscope based on standard usual criteria. RESULTS: Single bond showed more leakage at dentin margin than enamel margin in all three extraction periods and differences were significant among three groups (p < 0.05). In samples which were restored with Prompt L-Pop only in groups of 6 months there were significant differences between enamel and dentin margins. At enamel margin there were no significant differences between microleakage of groups according to the passage of time (p > 0.05). CONCLUSION: The results of this study using two different bonding systems, indicate that adhesion to enamel was more valuable than dentin and perhaps systems that include self-etching primers are less sensitive to remaining moisture on dentin and they are less affected during different time periods.

Effects of Rinsing Water Temperature and Preheated Composites on Microleakage of Composite Restorations with Two Bonding Agents.

Objectives: The aim of this study was to evaluate the effects of rinsing water temperature and preheated composites on microleakage of class V restorations with two different bonding agents. Materials and Methods: Eighty class V cavities were prepared in the buccal and lingual surfaces of 40 molars. Single Bond and Prime and Bond NT bonding agents were used. The teeth were divided into four groups of 10. G1: After acid etching, cavities were rinsed with 23˚C water and filled with 23˚C composite resin. G2: Rinsing water and composite resin had 55˚C temperature. G3: Rinsing water had 55˚C and composite resin had 23˚C temperature. G4: Rinsing water had 23˚C and composite resin had 55˚C temperature. The specimens were immersed in 0.5% basic fuchsine dye. Microleakage scores were analysed with the Kruskal-Wallis, Mann-Whitney U, and Wilcoxon tests. Results: There were significant differences in microleakage of specimens prepared with Single Bond and Prime and Bond NT only in group 1 (P<0.05). There were no significant differences between the microleakage of groups rinsed with different water temperatures (P>0.05). There were significant differences between the unheated and preheated composite groups (P<0.05). Conclusion: Preheating of composite is a valuable method to increase its adaptability and decrease microleakage of composite restorations.

Effect of Adhesive Resin as a Modeling Liquid on Elution of Resin Composite Restorations.

BACKGROUND: Adhesive resin is increasingly used as a modeling liquid for composite. Based on previous studies, elution of some components from the composite mass negatively affects the oral tissues. Since few studies have focused on the effect of adhesive resin on composite mass, this study aimed to investigate the effect of dental adhesion factors as modeling liquid on the elution of substances from composite restorations. MATERIALS AND METHODS: Sixty-four composite specimens (6 × 2 mm diameter × height) were prepared in four groups (n = 16) by using a Teflon ring. Composite mass was incrementally applied in four layers (0.5 mm). The control group contained no material between the layers, but other groups had one of the single bond, SE bond, and wetting resin adhesives between the layers. Specimens were immersed in distilled water and methanol. The amount of released triethylene glycol dimethacrylate (TEGDMA), urethane dimethacrylate (UDMA), and camphorquinone (CQ) was monitored by gas chromatography after 24 hours and 7 days. Data were analyzed with SPSS software through Kruskal-Wallis and Mann-Whitney U tests (α = 0.05). RESULTS: The highest rate of released TEGDMA comonomer was seen in the wetting resin group in the water medium. The highest rate of released UDMA monomer was seen in SE bond and wetting resin groups in the methanol medium after 24 hours. The highest amount of released CQ in the methanol medium was observed in the SE bond group after 7 days. CONCLUSION: Single bond adhesive can be used as modeling liquid since it has no significant effect on the elution of components from composite mass. Whereas, wetting resin and SE bond adhesives are not suitable to be used as modeling liquid due to the high amounts of released TEGDMA and UDMA.

An in vitro evaluation of the compressive strength and shear bond strength of resin-modified glass-ionomer cement containing purified powder of Salvia officinalis.

BACKGROUND: In this study, the effect of adding purified powder of Salvia officinalis on the mechanical properties and bonding ability of resin-modified glass ionomer (RMGI) cement is investigated. MATERIALS AND METHODS: In this in vitro study Purified powder of S. officinalis with particles smaller than 50 µ, in weight percentages of 0.5%, 0.75%, 1%, and 1.25%, was added to RMGI powder (GC Fuji II LC, GC USA). Fifty samples in five groups of control and percentages that considered, from the powder of GI combined with liquid, according to the manufacturer instructions and prepared samples with 4 mm × 6 mm dimensions and placing in distilled water in an incubator with temperature 37°C for 24 h. Fifty sound extracted upper premolars were collected and divided into five groups. The dentinal cross-sections on the occlusal surfaces of teeth were prepared and assessed under a stereomicroscope with ×16. Then, samples with 2 × 4 dimensions from RMGI was prepared on dentin surface and keeping in moisture environment in an incubator with temperature 37°C for 24 h. Compressive strength and shear bond strength test done with a universal testing machine at the rate of 0.5 mm/min. For the assessment of mode of failure, stereomicroscope with a digital camera and ×20 was used, and photographs from bonding surface were taken. After collecting data, the ANOVA test was used for comparing shear bond strength between groups and Kruskal-Wallis test was used for comparing compressive strength. The Chi-square test was used for comparing the mode of failure between groups. The significance level for all tests was considered 5%. RESULTS: According to the statistical analysis, compressive strength (P = 0.486) and shear bond strength (P = 0.076) were not significantly different between the five groups. The distribution of mode of failure was not significantly different between groups (P = 0.663). CONCLUSION: The addition of purified powder of S. officinalis to RMGI powder does not affect compressive strength and shear bond strength of RMGI cement.

Effects of ethanol concentrations of acrylate-based dental adhesives on microtensile composite-dentin bond strength and hybrid layer structure of a 10 wt% polyhedral oligomeric silsesquioxane (POSS)-incorporated bonding agent.

Background: The aim of this study was to assess for the first time the effects of different amounts of ethanol solvent on the microtensile bond strength of composite bonded to dentin using a polyhedral oligomeric silsesquioxane (POSS)-incorporated adhesive. Materials and Methods: This experimental study was performed on 120 specimens divided into six groups (in accordance with the ISO TR11405 standard requiring at least 15 specimens per group). Occlusal dentin of thirty human molar teeth was exposed by removing its enamel. Five teeth were assigned to each of six groups and were converted to 20 microtensile rods (with square cross-sections of 1 mm × 1 mm) per group. The "Prime and Bond NT" (as a common commercial adhesive) was used as the control group. Experimental acrylate-based bonding agents containing 10 wt% POSS were produced with five concentrations of ethanol as solvent (0, 20, 31, 39, and 46 wt%). After application of adhesives on dentin surface, composite cylinders (height = 6 mm) were bonded to dentin surface. The microtensile bond strength of composite to dentin was measured. The fractured surfaces of specimens were evaluated under a scanning electron microscope to assess the morphology of hybrid layer. Data were analyzed using one-sample t-test, one-way analysis of variance (ANOVA), and Tukey tests (α = 0.05). Results: the mean bond strength in the groups: "control, ethanol-free, and 20%, 31%, 39%, and 46% ethanol" was, respectively, 46.5 ± 5.6, 29.4 ± 5.7, 33.6 ± 4.1, 59.0 ± 5.5, 41.9 ± 6.2, and 18.7 ± 4.6 MPa. Overall difference was significant (ANOVA, P < 0.0001). Pairwise differences were all significant (Tukey P < 0.05) except those of "ethanol 0% versus 20%" and "20% versus 31%." All groups except "0% and 46% ethanol" had bond strengths above 30 MPa (t-test P < 0.05). Conclusion: Incorporation of 31% ethanol as solvent into a 10 wt% POSS-incorporated experimental dental adhesive might increase the bond strength of composite to dentin and improve the quality and morphology of the hybrid layer. However, higher concentrations of the solvent might not improve the bond strength or quality of the hybrid layer.

Comparison of Endodontic Medicaments on Bond Strength of Fiber Post to Root Dentin Using Resin Cement.

STATEMENT OF THE PROBLEM: Endodontic irrigants and medicaments may affect the bond strength of intracanal posts to root dentin. PURPOSE: The aim of this study was to compare the effect of calcium hydroxide (Ca(OH)2) and 2% chlorhexidine gel (CHX) on bond strength of fiber post cemented with resin cement to root dentin. MATERIALS AND METHOD: This in vitro experimental study was conducted on 36 mandibular premolars. Canals were prepared using the step back technique. After root canal irrigation, the teeth were divided into three groups of 12. Ca(OH)2 paste and CHX gel were used as intracanal medicaments in the first and second groups respectively. No intracanal medicament was used in the third group (control group). Access cavities were then sealed and the teeth were incubated for one week. The root canals were then filled using gutta percha and AH26 sealer and the teeth were incubated for 72 hours. Tooth crowns were then cut at the level of the cementoenamel junction and intracanal posts were placed. The teeth were mounted in auto-polymerizing acrylic resin, and incubated for one week .They were then sectioned into 1.5mm thick slices from their coronal surface using a fully automated cutting machine, and subjected to push-out test until failure. The load at debonding was recorded and data were analyzed using one-way ANOVA, post-hoc test and t-test. The coronal margin of the root was at the level of the surface of acrylic resin in the mold. RESULTS: The mean bond strength was 4.45 MPa in the Ca(OH)2, 2.45 MPa in the CHX and 2.48 MPa in the control group. The difference in this regard was statistically significant among groups (p= 0.04). The Ca(OH)2 group had significant differences with the CHX and control groups (p= 0.03 and p= 0.02, respectively). The difference between the CHX and control groups was not significant (p= 0.974). CONCLUSION: Based on the results, Ca(OH)2 increased the bond strength of fiber post to root dentin but 2% CHX had no effect on bond strength.

Evaluation of light curing distance and mylar strips color on surface hardness of two different dental composite resins.

INTRODUCTION: Hardness is one of the basic properties of dental materials, specially composite resins which is relevant to their polymerization. The aim of this study was to evaluate the effect of light curing distance and the color of clear Mylar strips on surface hardness of Silorane-based (SCR) and Methacrylate-based composite resins (MCR). MATERIALS AND METHODS: 40 samples of MCRs (Filtek Z250) and SCRs (Filtek P90) were prepared in size of 5 mm×2 mm (80 samples in total). The samples divided into 8 groups (10 samples in each one) based on the color of clear Mylar strips (white or blue) and distance from light curing source (0 mm or 2 mm). All the samples cured for 40 second and stored in incubator for 24 hours in 37°C temperature. Surface hardness test was done by Vickers test machine and the collected data were analyzed by one-way ANOVA and paired T-test by using SPSS software version 13 at significant level of 0.05. RESULTS: MCRs cured with blue Mylar strips from 0 mm distance had the highest (114.5 kg/mm(2)) and SCRs cured with white Mylar strips from 2 mm distance had the lowest (42.2 kg/mm(2)) mean of surface hardness. Also, the results of comparison among SCRs and MCRs showed significant differences among all groups (all P values <0.01). CONCLUSION: The hardness decreased as the distance increased and the blue Mylar strips provided higher hardness than clear ones. Also, Filtek Z250 showed higher hardness compared to Filtek P90.

Emdogain effect on gingival fibroblast adhesion in bioabsorbable and non-resorbable barrier membranes: An in vitro study.

BACKGROUND: Tissue engineering represents very exciting advances in regenerative medicine; however, periodontal literature only contains few reports. Emdogain (EMD) consists of functional molecules that have shown many advantages in regenerative treatments. This study investigated EMD effect on gingival fibroblast adhesion to different membranes. MATERIALS AND METHODS: Two dense polytetrafluoroethylene membranes (GBR-200, TXT-200), Alloderm and a collagenous membrane (RTM Collagen) were used in this experimental study. Each membrane was cut into four pieces and placed at the bottom of a well in a 48-well plate. 10 µg/mL of EMD was added to two wells of each group. Two wells were left EMD free. Gingival fibroblasts were seeded to all the wells. Cell adhesion was evaluated by means of a Field Emission Scanning Electron Microscope after 24 hours incubation. Data was analyzed by independent t-test, one-way and two-way ANOVA and post hoc LSD test. P < 0.05 in independent t-test analysis and P < 0.001 in one-way ANOVA, two-way ANOVA and post hoc LSD analysis was considered statistically significant. RESULTS: Alloderm had the highest cell adhesion capacity in EMD+ group and the difference was statistically significant (P < 0.001). In EMD- group, cell adhesion to TXT-200 and Alloderm was significantly higher than GBR-200 and collagenous membrane (P < 0.001). CONCLUSION: This study showed that EMD may decrease the cell adhesion efficacy of GBR-200, TXT-200 and collagenous membrane but it can promote this efficacy in Alloderm. It also showed the composition of biomaterials, their surface textures and internal structures can play an important role in their cell adhesion efficacy.

The effect of chronic periodontitis on serum levels of tumor necrosis factor-alpha in Alzheimer disease.

BACKGROUND: Despite the outbreak in dental science, oral and dental complications in Alzheimer are of the unsolved problems. It is assumed that tumor necrosis factor-α, which is a key factor in Alzheimer, has a relation with periodontal complications in patients with Alzheimer disease. The present study evaluated the effect of chronic periodontitis on serum levels of tumor necrosis factor-α in Alzheimer disease. MATERIALS AND METHODS: This case-control study was performed on 80 patients with Alzheimer disease seeking medical care at Nour Hospital, Isfahan, Iran. Eighty patients with Alzheimer disease between 40 and 70 years old attended this study. Forty had chronic periodontitis (case group), and 40 patients had healthy periodontium (control group). Blood sample was taken, and serum levels of tumor necrosis factor-α were measured by means of an ELISA Reader device. Independent T-Test was used to analyze data, and P < 0.05 was considered significant. RESULTS: The mean of tumor necrosis factor-α was 749.1 ng/µL in case group and 286.8 ng/µL in control group. Independent t-test showed that the mean of tumor necrosis factor-α in patients with Alzheimer and periodontitis was approximately three folds higher than the patients only with Alzheimer, and this difference was statistically significant (P < 0.001). CONCLUSION: According to the results of this study, it seems that there is a difference between serum levels of tumor necrosis factor-α in patient with Alzheimer and chronic periodontitis and patients with Alzheimer disease and healthy periodontium. Tumor necrosis factor-α level in serum may act as a diagnostic marker of periodontal disease in patients with Alzheimer disease.

Debris and smear layer removal efficacy and changes in morphology of dentinal tubules after using citric acid, tetracycline-hydrochloride and mixture of tetracycline and acid and detergent.

BACKGROUND: In periodontal diseases, contamination of roots with bacteria and their active biologic agents and smear layer formation following periodontal treatments, prevents reattachment of periodontal cells. As a matter of fact biomodification of root surface and removal of smear layer and debris is critical for regeneration of periodontal structures. The aim of this study was to compare the efficacy of smear layer removal by citric acid, tetracycline-hydrochloride (TTC-HCL) and mixture of tetracycline and acid and detergent (MTAD). MATERIALS AND METHODS: In this in vitro and experimental study, 12 impacted third molars were sectioned from cervical enamel junction (CEJ) to mid-root area into four dentinal specimens (n = 48). Three groups were conditioned by citric acid 3%, TTC-HCL 50 mg/mL and MTAD by means of cotton pellets, which were changed every 30 s for 3 min. The control group was conditioned by distilled water. Images from scanning electron microscope (SEM) were examined by two different analyzers. Data was analyzed by Kroskal Wallis and Mann-Whitney statistical analysis. RESULTS: The mean of dentinal tubules diameter was the most in MTAD group and the least in TTC-HCL and this difference was statistically significant (P = 0.05). CONCLUSION: According to the present study, TTC-HCL could remove debris and smear layer but citric acid and MTAD had better debris and smear layer removal efficacy and demineralization effect in comparison with TTC-HCL.

The effect of adjunctive low-dose doxycycline and licorice therapy on gingival crevicular fluid matrix metalloproteinase-8 levels in chronic periodontitis.

BACKGROUND: This study compared the effect of adjunctive low dose doxycycline and licorice on gingival crevicular fluid (GCF) matrix metalloproteinase-8 (MMP-8) levels in patients with chronic periodontitis. MATERIALS AND METHODS: In this in vivo, experimental study 39 patients with mild to moderate chronic periodontitis were selected. Samples of GCF were collected from three deepest pockets and MMP-8 concentration was measured. Patients were divided into three groups (n = 13). Groups were treated with doxycycline, licorice and placebo. Sampling and measurement of MMP-8 was repeated after 6 weeks. Data was analyzed by t-paired and ANOVA test. P > 0.001 was considered significant. RESULTS: The decrease in mean of MMP-8 concentration was higher in doxycycline and licorice group in comparison with the placebo group and the difference was statistically significant (P value > 0.001). The decrease in mean of MMP-8 concentration was higher in licorice group than doxycycline group, but the difference was not statistically significant. CONCLUSION: The present study showed that licorice extract can prevent the production of MMPs by host cells and can be as useful as antibiotics like doxycycline to cure periodontal and other inflammatory diseases. It must be added that no side-effects were observed in usage of licorice extract.

The effect of three irrigants on the coronal leakage of the root canals system irrigants.

INTRODUCTION: The production of smear layer during canal instrumentation is thought to increase coronal microleakage even after canal obturation. Previous studies have shown that the type of irrigant does not necessarily affect the seal of the obturation. Our study aimed to evaluate the effect of three irrigation solutions (MTAD, citric acid and EDTA/NaOCl) on the coronal microleakage of root canals. MATERIALS AND METHODS: Fifty five intact single rooted teeth were instrumented and randomly divided into three experimental groups (15 teeth each) and two control groups (5 teeth each). Final irrigation was carried out with MTAD in group I, citric acid in group II, and EDTA/NaOCl in group III. EDTA/NaOCl was used for the negative control group and saline irrigation was carried out in the positive control group. After lateral compaction with gutta-percha, the access cavities of the experimental specimens were restored with temporary restorative material. Temporary cement was not used in the positive control group. In the negative control group, access cavities and foramen apices were sealed with glass ionomer. Microleakage of samples was measured using the dye penetration technique. Data were analyzed with ANOVA and Tukey test to determine statistical differences between groups. RESULTS: MTAD, citric acid and EDTA/NaOCl all had less microleakage compared to normal saline. However, no difference was detected between the experimental groups. CONCLUSION: In this study, all three groups demonstrated effective seal with gutta-percha obturation. This is likely to be due to various factors including their ability to remove smear layer.