[In-Vitro evaluation of the effect of sage on shear bond strength of composite resin to bleached enamel]

There is a reduction in bond strength of composite resin to bleached enamel. The aim of the present study was to evaluate the effect of sage [Salvia officinalis] on the shear bond strength of composite resin to bleached enamel In this in vitro study, 60 labial surfaces of maxillary incisors were randomly divided into 4 groups as follows: G1: bleaching; G2: bleaching and application of sodium ascorbate-containing solution; G3: bleaching and application of Salvia officinalis-containing solution; G4: control [no bleaching]. A composite resin [Z100; 3M ESPE, Dental products, St Paul, MN, USA] cylinder was bonded on each specimen after acid etching and application of a fifth generation bonding agent [Single Bond; 3M ESPE, Dental products, St Paul, MN, USA]. After thermocycling, the shear bond strengths of the samples were measured in MPa. Data were analyzed using one-way ANOVA and Tukey's HSD test [alpha=0.05] Minimum and maximum mean values of shear bond strengths were observed in G1 [12.31 +/- 2.44] and G3 [25. 04 +/- 3.52], respectively. No statistically significant differences were found in bond strength between the bleached and non-bleached groups after the antioxidant treatment [P>0.05]. There is a considerable decrease in bond strength of composite resin to enamel immediately after bleaching. Application of sodium ascorbate and Salvia officinalis solution can increase the bond strength of composite resin to bleached enamel

[ effect of metal primer on the retention of casting posts]

Statement of Problem: Retention of dental posts is an important factor for the longevity of final restorations in endodontically treated teeth. It can be influenced by such factors as the type of post, type of cement, the bond between the cement and dentin, and also cement with post surface

Purpose: The purpose of this study was to investigate the effect of a metal primer on the retention of casting posts luted with resin cement

Methods and Material: The crowns of 30 intact canine teeth were removed at CEJ with a disc. After root canal treatment, the post space was prepared in each specimen to a depth of 12mm. The posts were casted of non-precious alloy and sandblasted. The teeth were randomly divided into two groups [n=15]. For both groups, casting posts were cemented into post spaces using panavia F2 according to the manufacturer.s instruction. The posts in group 1 were additionally pre-treated with Alloy Primer. The specimens were thermocycled and then debonded on an instron machine with a crosshead speed of 1 mm/min. The force required for dislodgement of the posts from the prepared spaces was recorded and the results were analyzed using t-test. Stereomicroscope was used to study the fracture interface in both groups

Results: The mean retention forces were 112.45 +/- 28.37 N for group 1 and 59.5 +/- 7.19 N for group 2. A statistically significant improvement in retention was found in the specimens in group 1 as compared with group 2 [p <0.05]. Stereomicroscopy showed that failure at cement-post interface was 20% in group 1 and 60% in group 2

Conclusion: Under the conditions of this study, casting posts pre-treated with metal primer provided a significantly greater retention

[Influence of the baseline concentration of fluoride in saliva and salivary pH level on dmft index in 5-year-old children residing in Hamadan]

Fluoride is the most important mineral in the prevention of tooth caries. This study evaluated the relationship between salivary pH levels, fluoride baseline concentration in saliva and dmft index in 5-year-old children attending kindergartens in Hamadan, during 2004. A total of 200 children [100 male and 100 female], 5 years of age were selected for this cross sectional study. The dmft indices were determined through examination of all subjects using a dental mirror and explorer under natural light. 100 children [50 male and 50 female] were divided into 2 groups: dmft>l and dmft<1 which constituted the case and control groups, respectively. Approximately 1-3 ml unstimulated saliva was collected from each subject and fluoride concentration was measured in ppm using a fluoride ion selective electrode. The pH of all samples were assessed by a pH meter. The data were analyzed using T-test. Fluoride concentration and salivary pH levels were 0.0113 +/- 0.007 ppm and 6.74 +/- 0.28 in the case group and 0.0321 +/- 0.011 ppm and 6.53 +/- 0.44 in the control group, respectively. A statistically significant relationship was observed between the baseline fluoride and pH levels of saliva and dmft indices. According to these results an appropriate concentration of fluoride in the saliva and an increased pH can reduce the dmft index in children

[Comparison of the effectiveness of three mouthwashes on oral microflora: an in vitro study]

The use of mouthwashes for plaque control and preventing its accumulation on teeth and adjacent mucous membranes is of considerable importance. The aim of this investigation was to compare the effectiveness of chlorhexidine and two Irsha mouthwashes, on aerobic microorganisms in oral flora. In this in vitro study, the diffuse-agar method was used to effects of antiplaque antitartar Irsha mouthwash, antiseptic Irsha mouthwash and 0.2% chlorhexidine on oral aerobic microorganisms. The microorganisms were dispersed and plated on blood agar or Muller Hintone medium. Six-millimeter paper disks immersed in each of the study solutions were inserted into the plates after the incubation period. This procedure was repeated 4 times for each of the microorganisms and the inhibition zones were measured for each microorganism and mouthwash, separately. The data were analyzed using ANOVA and Tukey HSD [post hoc] tests. Antiplaque Irsha was useful in controlling some of the analyzed microorganisms including lactobacilli, Neisseria sicca, C. diphtheroid, Streptococcus salivarius, Streptococcus viridans and Streptococcus mutans, in decreasing order. Antiseptic Irsha did not affect the aerobic bacteria. Chlorhexidine was effective on all complex infections consisting of the studied aerobic microorganisms, especially lactobacilli and Staphylococcus epidermidis. It also successfully controlled Staphylococcus aureus followed by Brevudimonas, Neisseria sicca, Streptococcus salivarius. Streptococcus mutans, Pseudomonas aeruginosa and Streptococcus viridans, in that order. According to these results, 0.2% Chlorhexidine demonstrated a superior antimicrobial effect in most cases as compared to the studied mouthwashes

[Comparison of the microleakage and shear bond strength of four current one component dentin bonding systems]

The success of tooth-colored restorations depends on bonding them to hard tooth tissue that will retain the restoration to the cavity preparation and prevent microleakage. Different adhesive systems have been introduced that provide bonding between tooth-colored filling materials and tooth structure [dentin] that will withstand the contraction forces generated by polymerization shrinkage while maintaining a marginal seal during functioning of the restored tooth. The purpose of this investigation was to study the microleakage of class V resin restorations and the shear bond strength of composite resin to dentin using four different types of current bond adhesive systems. This experimental study has been done on 96 intact human premolar teeth extracted for orthodontic purposes within a 3-month period. The teeth were randomly divided into two parts as A and B. In part A, Standardized classic class V cavity dimensions of 3.0 mm [occlusal-gingival], 2,0 mm [mesial-distal], and 2.0 mm [depth] prepared in buccal and lingual surfaces of teeth at the cemento-enamel junction with the cervical margin in dentin or cementum and the occlusal margin in enamel. Enamel Cavosurface margin of cavities were beveled. The cavities were etched with 36% phosphoric acid for 15 second then were rinsed. The cavities were restored with a composite resin [Z100 3M ESPE] using four different dentin adhesive systems [Single Bond [3M-ESPE], Excite [vivadent], One-Step [Bisco], Prime and Bond NT [Dentsply-Detry]], The specimens' thermocycled for 3000 cycles [5-55°C] and were then immersed in a 10% solution of methylene blue dye for 72 hours. After rinsing, the restorations were sectioned buccolingualy and the microleakages were scored by an optical stereomicroscope with x40 magnification. In part B, the teeth mounted in a 2.5 cm diameter acrylic cylinder mold and buccal surfaces of teeth were ground to expose dentin. After etching and rinsing, the four adhesive systems mentioned before were applied to dentin surface with the wet bonding technique. A cylinder of Z100 dental composite with a 3 mm diameter and 2 mm height was placed on the adhesive covered dentin surface of all groups and light-cured. The specimens were kept in distilled water at room temperature for one week and then thermocycled for 3000 times [5-55oc].Shear bond strength of specimens was measured using an instron universal mechanical testing machine with the cross-head speed of 0.5 mm/minute. Data were analyzed with one way ANOVA, Kruskal-Wallis, Tukey HSD and Mann-Whitney U tests. The mean and standard deviation of shear bond strengths [Mpa] of groups were as follows: One-Step:19.60 +/- 1.83, Single Bond: 21.44 +/- 3, Prime and Bond NT: 26.51 +/- 5.02, Excite: 29.78 +/- 3.85. Analysis of the results revealed that One-step had lowest and Excite had highest shear bond strength [P<0.05]. Prime and Bond system had the least and One-Step system had the most microleakage in dentin margins of restorations [P<0.05]. Single Bond and Excite bonding systems statistically had no difference in dentin marginal microleakage [P>0.05]. Different types of one bottle dentin bonding agents had different micro leakage scores and different shear bond strengths

[Invitro comparison between the effects of two tooth bleaching agents on surface micro hardness of microhybrid composite]

Tooth whitening products may have effects on various properties of restorative materials including hardness. This study investigated the effects of two at-home bleaching agents [Kimia 16%, Opalescence PF 15%] on hardness of a microhybrid composite. Thirty cylindrical-shaped specimens of microhybrid composite Z250 [3M, Dental Products, USA] with 5mm diameter and 2mm height were prepared and divided into three treatment groups comprising a control and two different bleaching groups. Control specimens were stored in distilled water for two weeks. Specimens of bleaching groups were exposed to the bleaching agents [Kimia 16% the first bleaching group and opalescence 15% for the second group] 1 hour daily for 2 weeks. After treatment, the hardness of specimens was tested using Vickers-test Instrument under 300 gr load for 15 seconds. The data were analyzed using One-way ANOVA and Tukey tests [alph=0.05]. The mean composite microhardness for control, Kimia and Opalescence groups were 97.93 +/- 4.59, 95.56 +/- 2.75 and 86.57 +/- 2.59 respectively. It was observed that the bleaching materials softened the composite Z250. However, ANOVA showed the difference between Kimia group and control group was not significant [P=0.280]]. Hardness of Opalescence group was significantly lower than the two other groups [P=0.000]. Regarding the decreased microhardness of microhybrid composite, Kimia 16% at-home bleaching agent is more desirable than Opalescence PF 15%

[ vitro comparison of two tray bleaching agent: Kimia 16% and Opalescence PF 15%]

Esthetic dentistry and tooth esthetics are important parts of dental treatments today. Among these, Tooth bleaching treatment is a simple, safe and effective way to accommodate many patients' needs. Regarding to production of dental materials in Iran, this in-vitro study was conducted to compare the whitening effect and the speed of efficiency of bleaching agents [kimia 16% and Opalescence F 15%] using a tray. This experimental study was performed on forty extracted caries free maxillary central incisors which did not have any fluorosis and tetracycline discoloration. Roots of the teeth were covered with 2 layers of nail polish and they were divided into two groups then embedded in red wax. After preparing the bleaching tray for two groups, photographs of teeth were taken and the values of the teeth were determined visually using a vita shade guide. Afterwards the teeth were treated by carbamide peroxide gels [Kimia 16% and opalescence PF 15%] for an hour a day for two weeks. The lightness of the teeth were evaluated every day before treatment and also one month after the treatment period and the data was recorded. The data were analyzed by Signed T test, ANOVA and Mann-Withney U tests. The findings of this study showed that whitening effects of the two agents were statistically significant [P<0.01]. At the end of the study according to the recorded value, the lightness change in groups treated with Kimia was 6 degrees and in the other group [Opalescence PF], it was 6.3 degrees. There was no statistically significant difference between the two bleaching gels [P>0/05]. Using the tray bleaching method, both gels [16% Kimia and 15% Opalescence PF] had equivalent effects on whitening of the teeth

[ comparison between mechanical and chemomechanical methods in dentinal caries removal [Invitro]]

Aim and Background: chemomechanical method refers to the chemical removal of the decayed dentin and then to the slow elimination of caries with hand instruments conservatively. The goal of this study was to compare the remaining dentinal caries between this method and the conventional mechanical method using burs

Methods and Materials: the samples of the first group were treated by chemomechanical method applying carisol TM gel whereas those of the second group were treated by mechanical method using burs. After caries removal, the samples were suctioned and examined by stereomicroscope. The data were submitted to statistical analyses [x2 and Mamm - Withney U tests]. The frequency of the remaining caries, for both groups, was 23.3%, however, the surface area of the remaining caries in mechanical and chemomechanical groups were 0.049 and 0.008 mm, respectively. The differences were not statistically significant

Results: the results of this study no significant differences between two methods

Conclusion: chemomechanical method as a suitable substitude for the conventional method in caries removal