[Effects of casein phosphopeptide amorphous calcium phosphate and casein phosphopeptide amorphous calcium phosphate fluoride on alterations of dental plaque pH following sucrose consumption]

Plaque pH drop after consumption of sugary materials may dis-solve enamel minerals. Casein phosphopeptide amorphous calcium phosphate [CPP-ACP] is a paste enriched with calcium and phosphate. The new formulation of this paste, casein phosphopeptide amorphous calcium phosphate fluoride [CPP-ACPF], contains 900 ppm fluoride. This paste can neutralize the low pH of bacterial plaque. This study compares the efficacy of CPP-ACP and CPP-ACPF for neutralizing plaque acidity at different time points. This clinical trial was conducted on 40 students. Plaque pH at the distal of first molar was measured before and 10 minutes after the consumption of 10% sucrose solution. In the next step, CPP-ACP and CPP-ACPF pastes were applied as recommended by the manufacturers to the tooth surface. Plaque pH was measured at 30 minutes, 60 minutes and 24, 48, 72 and 96 hours. Data was recorded and analyzed by repeated measures ANOVA [P<0.05]. Both CPP-ACP and CPP-ACPF increased plaque pH similarly in the first 48 hours. However, the pattern changed from this time point on. CPP-ACP and CPP-ACPF had similar efficacy for up to 48 hours, but CPP- ACPF was capable of keeping the pH high by up to 96 hours

[In-vitro comparison of primary setting time and surface porosity in two brands of MTA

There are disadvantages in using MTA, such as the extended setting time and the difficulty in its manipulation. The aim of this in vitro study was to compare the primary setting time and surface porosity of two commercial brands of tooth colored MTA. In this experimental study two brands of MTA were evaluated; Group 1: ProRoot MTA [Dentsply, USA], and group 2: Angelus MTA [Angelus, Brazil]. Five samples of each material were prepared and evaluated for primary setting time with a Gilmore needle according to ISO 6876: 2001 with a cylindrical stainless steel mold [10mm×1mm] in an incubator with 37 +/- 1 degrees centigrade and relative humidity of over 95%. Specimens were prepared and observed under a scanning electron microscope [SEM] for surface porosity. Data were analyzed with T-test. Primary setting time of the materials were 38.72 +/- 0.61 and 22.46 +/- 0.61 ProRoot and Angelus MTA, respectively. Statistical analysis revealed that the differences between setting times of the materials were significant [p<0.001]. ProRoot MTA showed better surface characterization compared with Angelus MTA. The primary setting time of Angelus MTA was lower than that of ProRoot MTA but the surface characterization [topography and porosity] of ProRoot MTA was better than that of Angelus MTA after final setting time

[Clinical comparison of dental caries by DMFT and ICDAS systems]

The common method of caries status evaluation is the number of decayed, missed and filled teeth [DMFT] index. Recently the International Caries Diagnosis and Assessment System [ICDAS] has been introduced for a detailed evaluation of the dental caries. The aim of this study was to evaluate the caries status with this new system while comparing it with the DMF index as a common method. A total of 110 dental students were selected randomly and examined. Examination was done in the dental unit under good light circumstances. First, all surfaces of the teeth were cleaned with a brush, rubber cup and prophylaxis paste and then rinsed. Subsequently, examination was performed in each person by two calibrated examiners according to DMFT system and ICDAS [evaluation of teeth status in occlusal and smooth surfaces in dry and wet situations according to codes of this system] and the information forms were completed. Chi square statistical test was used for data analysis. The mean DMFT was 7.16. According to ICDAS system nobody had 00 code meaning that at least one surface of 182 dental surfaces had a lesion. Only seven cases had codes 00-02. The results for codes 03 through 06 were as follow, respectively: 51, 49, 34, 2. Ninety nine cases had extracted or non-examinable teeth. The interexaminer kappa coefficient was 0.916. The new system, ICDASl, provides more accurate information than DMF for the investigators and epidemiologists. The DMFT number does not show any details about the dental status of the cases

In-vitro evaluation of water sorption and solubility of G-Cem and Fuji Cem in water and acid

Solubility is among the negative characteristics of dental materials leading to structural degradation of cements and decreased longevity of restorations. The present study sought to assess the water sorption and solubility of FujiCem resin-modified glass ionomer [RMGI] and G-Cem self-adhesive resin cement in water and acid. In this experimental study, 5 discs were fabricated from each understudy cement for solubility testing in lactic acid and 5 other disc-shaped specimens were made for evaluation of water sorption and solubility. Specimens were immersed in distilled water for 7 days and immediately weighed afterwards [M2]. Discs were then transferred to a desiccator again to reach a constant weight of M3. Water sorption and solubility were calculated using the respective equations. For acid solubility testing, specimens were immersed in lactic acid for 24h. Independent t-test was applied for statistical analysis of results. Solubility in distilled water was 0.0000139 +/- 0.0001 microg/m[3] for FujiCem and 0.0000016 +/- 0.000005 microg/m[3] for G-Cem [P=0.480]. Water sorption was 0.0000197 +/- 0.000234 for FujiCem and 0.0000025 +/- 0.00004 for G-Cem [P0=001]. Acid solubility was 0.0059414 +/- 0.0016 for FujiCem and 0.0039115 +/- 0.0016 microg/m[3] for G-Cem [P=0.348]. The two understudy cements had no significant difference in water or acid solubility but FujiCem RMGI showed greater water sorption than G-Cem self-adhesive resin cement

30-month follow-up ofstepwise excavation without re-entry with three different biomaterials: a case report

Restoration of deepdental caries without pulp exposure is usually challenging for dentists. In order to prevent pulp exposure and subsequent root canal therapy [RCT], indirect pulp capping is usually performed. Step wise excavation [SE] is a conservative method that canreduce the incidence of pulp exposure and maintain tooth vitality without the need for RCT. Considering the high prevalence of dental caries among the Iranian population, knowledge about this treatment modality canbe beneficial for dentists. A 23 year-old patient with three deep carious lesions presented toour dental clinic. The teeth had normal responses to thermal tests and percussion. Due tothehighrisk ofpulp exposure following conventional complete excavation of caries, step wise excavation treatment was done. Three different lining materials [calcium hydroxide, MTA, CEM cement] were used to cover the remaining caries. The teeth were restored using posterior restorative glass ionomer [Fuji9, GC, USA]. The teeth were followed weekly inthe first month and then every six months up to 30 months clinically and radiographically. At30-month follow-up, the teethdid not show any sensitivity to cold or percussion,had no spontaneous nocturnal painor irreversible pulpitis symptoms and did not need RCT; these signs were all indicative of asuccessful treatment

Comparing the effect of total-etch and self-etch on shear bond strength of fissure sealant on primary teeth enamel

Different clinical steps, weak and ineffective bond are some of the problems of using fissure sealant in primary teeth. The aim of this study was to compare the effect of a total-etching adhesive [single bond] and a self-etching adhesive [G bond] on the shear bond strength [SBS] of a light curing pit and fissure sealant with primary enamel. In this experimental study, the crowns of 10 caries-free primary molars were sectioned in a bucco-lingual direction. These 20 specimens were randomly assigned into two groups [single bond and G bond]. A light curing pit and fissure sealant [Concise] was bonded to the enamel following application of each bonding system. After 24 hours, the shear bond strength was measured. The data were statistically analyzed using t-test. The failure mode was determined in a stereo microscope atx20. The shear bond strength of single bond [16.71 +/- 0.72] was higher than the G bond [9.62 +/- 1.4]. There was a significant difference between the shear bond strength in two groups [p<0.05]. Most failures were cohesive [80% in single bond and 90% in G bond]. According to our data, the self-etching adhesives [G bond] are not reliable alternatives to the total-etching adhesives, if strong bond strength is needed

[ vitro comparison of solubility of resin modified glass ionomer and a base containing hydroxyapatite in water, acid and artificial saliva]

Solubility is one of the shortcomings of dental materials that causes decreased physical and mechanical properties and longevity of the restoration. The aim of this in vitro study was to compare the solubility of the resin modified glass ionomer cement and a base containing hydroxyapatite. This experimental study was carried out according to ISO4049:2000[E] and ISO 9917-1:2007[E]. Ten samples of each of the two materials including resin modified glass ionomer and a base containing hydroxyapatite were evaluated for solubility in distilled water and artificial saliva. Evaluation of acid solubility was performed in lactic acid with pH=2.7 +/- 0.02 for 24 hrs. The data were analyzed by two-way ANOVA test. The mean values of solubility in distilled water for RMGIC and base containing hydroxyapatite were 0.6 [ +/- 0.3] and -1.6 [ +/- 1.4], respectively. The means of saliva solubility were 0.007 [ +/- 0.8] and 1.07 [ +/- 1.4], respectively for the mentioned materials. The mean value of acid solubility was 0.000474 [ +/- 0.000784] for RMGIC and 0.000334 [ +/- 0.000221] for Lime-lite. There was no significant difference between values of water sorption and solubility of the two materials [p>0.05]. The solubility of the two tested materials in distilled water, artificial saliva and acid was very little and there was no significant difference between them in this regard

[Comparing the effect of three self-etching bondings on human dentin shear bond strength and micro leakage]

Microleakage and shear bond strength in composite restorations are the most problematic challenges to days. There is disagreement about bond strength in the literature. On that basis this invitro study was designed to evaluate micro leakage and shear bond strength of three bondings, Adhese, Prompt L-pop, clearfil SE bond, in composite cavities. This experimental study was performed on 60 freshly extracted non carious human premolars. 30 samples were used to test microleakage and 30 for shear bond strength. Class V cavities were prepared in buccal surface of 30teeth with dimensions of 2x2x3 mm so that the gingival margins located 1 mm below the CEJ and occlusal enamel margins beveled to 0.5 mm. Samples were randomly divided in to 3 groups of 10 teeth each; group A: Clear fill SEbond, Group B: Prompt L pop, Group C: AdheSE. Cavities were then filled with Z100 [3M, ESPE, USA]. 30 other samples were grounded up to 1mm below the central groove to expose fresh dentin, then composite tubes were bonded to dentin according to bonding strategy of the group. Shear bond strength was evaluated with Zwick [Roel, Germany] testing machine and microleakage with stereomicroscope. Microleakage was recorded and Kruskal-Wallis analysis was performed followed by Mann-U-Whitney tests. Statistical differences in shear bond strength of tested bondings were determined by ANOVA followed by Tukey test. There was a significant difference in regard to micro leakage between the studied groups [p<0.005] with the minimum leakage in SE bond group [1 +/- 0/75] and the maximum in Prompt-L-pop group [2/15 +/- 1/15]. Shear bond strength analysis revealed statistical significant differences between Group A and the 2 others with the superiority of Group A [p<0.001]. With the limitation of this in vitro study we concluded that :Among 3 self etching dentin bonding agents used in this study Clear fill SE bond showed the highest level of shear bond strength and Among 3 self etching dentin bonding agents used in this study Clear fill SE bond showed the least micro leakage

[Effect of light polymerization on color change of composite]

Color matching has an important role in esthetic dentistry. The aim of this study was to evaluate composite color changes after polymerization. In this experimental study, sixty cylinders of six different composite [Z100, Tetric-ceram. Point 4, Charisma, Glacier, Clearfil ST] were prepared with 3mm diameter and 2mm thickness [10 each]. A frissete was placed under cylinders, composite resin was packed in each cylinder and other frissete was located on the cylinder. Digital camera was fixed at a distance of 3 cm from specimens with 45 degree angle. Photographs were taken before and after polymerization with a professional digital camera in standard daylight. Data were recorded in CIE Lab system. Color shifts were calculated as delta E. The "L" value increased in "Clearfill ST" composite resin and decreased in other composites after polymerization. The "a" value increased in "Clearfill ST" composite resin and decreased in other composites after polymerization. The "b" value increased in "Z100 and Glacier" composite resin and decreased in other composites after polymerization. All composites showed color changes [delta E<3.3]. The highest color change was measured in Z100 [delta E10.75] and the least in Tetric-ceram [delta E=3.79]

[Effect of Amalgam and Ariston pHc on tooth demineralization]

The objective of this study was evaluation of the effect of Ariston pHc and Amalgam restorations on demineralization of tooth structure. 28 maxillary upper first premolars that were extracted from the mouth for orthodency were divided into 2 groups, group 1 [control]: 14 teeth without any restoration. group 2 [case]: 14 teeth with a cavity of 2mm depth and 2mm width in middle one third of buccal and lingual surface was created and in each too,the cavity was restored with Amalgam [cinalux,Iran] and the other one with Ariston pHc. [vivadent, Lichtenestein. All the samples were exposed to demineralization solution [for 6 hours] and remineralization solution [for 18 hours] This took 2 weeks .later the, teeth [both groups] were mounted and sectioned buccolingually in the middle of every restoration. Microhardness analysis were done with Microhardness Tester [Buehler, Germany]. Vickers hardness of teeth around Ariston pHc restorations was significantly higher than Amalgam restorations [P< 0/05]. Ariston pHc is more effective in reducing demineralization of tooth structure than Amalgam