effects of opaque and clear pit and fissure sealants on infrared laser fluorescence measurements

Statement of the Problem: The purpose of placing sealants is to inhibit caries by physical closure of the pits and fissures of teeth. A device named DIAGNOdent is useful in detecting occlusal caries by employing laser fluorescence [LF]. However, there are contradictory results in the influence of sealants on LF measurements

Purpose: The aim of this study is to investigate the effects of two different types of fissure sealants on LF measurements

Materials and Method: In this in vitro study, 86 extracted permanent third molars were divided randomly into two groups and clear or opaque sealant was applied on the occlusal surfaces. Two examiners performed pre- and post-seal fluorescence measurements twice with one week interval by employing DIAGNOdent device. Finally, measured values were evaluated through the statistical paired t-test by means of SPSS 17 software

Results: The mean value of LF measurements increased significantly due to the application of clear sealant [p= 0.001] while the statistical changes in this measurement was negligible after applying opaque sealant [p= 0.311]

Conclusion: Clear sealants increase the LF measured values but opaque sealants cause almost no changes. Therefore, DIAGNOdent device is not reliable for detecting caries beneath the clear sealant

[Effect of saliva contamination on the shear bond strength of two types of glass- ionomer cements to dentin in primary teeth]

Use of glass ionomer cements in pediatric dentistry is increasing and limited information exists with regard to the effect of salivary contamination on the shear bond strength of glass-ionomer to dentin in primary teeth. The aim of this study was to evaluate the effect of salivary contamination on the shear bond strength of two types of glass ionomer cements to dentin in primary teeth. A total of 36 human extracted primary molars were used in this study. The specimens were divided into two groups for each material and then further subdivided into three groups: group 1: uncontaminated, group 2: contaminated with saliva, group 3: contaminated, washed and air dried. The specimens in groups I, II, III were bonded to glass-ionomer and in groups IV, V, VI to resin modified glass-ionomer. Shear bond strength was measured using an Instron machine at 1 mm/min cross head speed. Data were analyzed with ANOVA and Tukey test. There were significant differences in the mean shear bond strength among groups IV, V [P=0.05]. There were no significant difference among groups I and II [P=0.16], I and III [P= 0.93] and IV and VI [P=0.98]. Results showed that salivary contamination can decrease the mean shear bond strength of light- cured glass-ionomer to dentin in primary teeth

[Influence of ZOE and formocresol on the shear bond strength of composite to dentin in primary teeth]

Dentin contamination with different materials used in pediatrics is effective on the bond strength of adhesives to primary teeth. Therefore, the purpose of this in vitro study was to evaluate the effect of zinc oxide-eugenol and formocresol on the shear bond strength [SBS] of resin composite to the dentin in primary teeth. A total of 72 extracted second morals were selected and mounted in acrylic resin. Buccal and lingual dentin surface were prepared and randomly allocated into 4 groups of 18 specimens each. Groups were subjected to different treatments as follows: group A, the surfaces were received no pretreatment and served as control; group B, the surfaces were covered with a paste of ZOE [Zoliran]; group C, the surfaces were covered with a paste of ZOE [Kemdent]; group D, specimens were placed on gauze soaked in formocresol. The specimens were covered with tinfoil and stored in distilled water at 37oC for 7 days. The temporary restorations were removed after one week. The dentin surfaces were treated with single bond adhesive resin 3M [ESPE/USA] according to manufacturer's instructions and light cured for 20 seconds. Composite P60 columns [4 mm internal diameter and 3 mm height] were applied on the prepared surfaces and light cured for 40 seconds. Shear bond testing were carried out after 24 hours with a cross head speed of 0.5 mm/min. Statistical analysis was conducted using one-way ANOVA and Tukey Post-hoc test. The mean shear bond strengths were 17.52 +/- 3 MPa for group A, 15.41 +/- 3.3 MPa for group B, 15.63 +/- 3.2 MPa for group C, and 18.57 +/- 3.8 MPa for group D. There was no significant difference between the shear bond strength of group A compared with those of groups B, C, and D [P>0.05]. The bond strength of composite to dentin in primary teeth was not influenced by the zinc-oxide eugenol [Zoliran and Kemdent] or formocreosol

[Comparison of shear bond strength of four self- etch and total -etch bondings in dentine of primary teeth; an in vitro study]

Conservative procedures using dentine adhesives are one of the important aspects of pediatric dentistry. The bonding performance of current adhesive systems to primary dentine has not been thoroughly researched. The aim of this study was to evaluate shear bond strength of four adhesive systems bonded to primary molars dentine. For this experimental study, 48 extracted primary human molars were collected and stored in normal saline at room temperature. For shear bonding test, the labial or lingual surfaces of the primary molars were used. The flat buccal/lingual surfaces of the teeth were divided into four groups [n=12]. The tested adhesives were: Clearfil SE Bond [SE]; Adhese [AS]; Prime and Bond NT [NT] and Exite [EX]. Four dentine adhesives were applied following the manufactures' instructions. Composite [Z100] cylinders [3x4mm] were polymerized on the treated dentine surfaces and specimens were stored in normal salin for 72 hours prior to testing. After themocycling, the teeth were subjected to shear stress using a universal testing machine [Instron] at a crosshead speed of 1mm/min. The results were analyzed with ANOVA and Tukey's HSD test. The shear bond strength values ranged from 4.71 to 26.68 Mpa on dentine, in decreasing order of SE, NT, EX and AS. The differences in bond strengths between the four groups were statistically significant [p =0.0001]. Adhesives systems are technique sensitive and in pediatric dentistry, choice of adhesive system may be affected not only by physical properties of the materials but also by factors related to the method required for their application

[Assessment of correlation between dye penetration and electrochemical methods on apical microleakage]

The most important failure factor of root canal treatment is lack of proper seal of root canal, which leads to leakage and penetration of microorganism in to the canals. Different methods have been used to determine the apical seal This study was aimed at comparing the apical leakage using dye penetration and electrochemical methods successively used on the same teeth. For this experimental study, 31 freshly extracted anterior single root human teeth with straight root canals were selected. The specimens were randomly divided into experimental, positive and negative control groups. Root canals of the experimental and negative group were filled, and positive group were left unfilled. The external surface of each tooth was coated with two layers of the nail polisher, except for the apical 2mm and coronal portion. Leakage of the teeth were measured using electrochemical me thud. Two copper wires were used as electrodes and normal saline solution was used as electrolyte. Then coronal portions of the roots were filled using ZOE cement and coated with two layers of the nail polisher. The teeth were immersed in 2% basic Fuchsine for 48 hours and were washed in tap water. The roots were then split longitudinally and dye penetration was assessed for each tooth. The data were analyzed using t-test and Pierson correlation coefficient test. The obtained results in electrochemical methods varied from 3.1 to 54.7 Micro amper, while in dye penetration method the observed leakage was 2.5 to 6.8 mm. The coefficient correlation between the two methods was found to be 0.204 [r = 0.204, p 0.5] Since no correlation was found among the results obtained with the two methods, it is concluded that, for assessment of the marginal leakage of dental materials, various methods should be considered

[ comparative assessment of apical microleakage of primary teeth when filled with two different techniques]

Non-reinforced ZOE is the substance that is commonly used in pulpectomy and filling primary teeth canals. Two different ways may be used plugger or lentulo spiral to carry ZOE into the canals. The aim of this study was to compare the degree of microleakage in pulpectomy of primary teeth with each of these two different ways. In this experimental study, 44 single rooted primary teeth from maxilla were used based on convenience sampling. First, pulps of all the teeth were removed and all of them were filed. Then all the samples were divided into four groups randomly, two experimental groups each with 20 cases and two smaller groups each with only 2 cases as positive and negative control. In the first experimental group, dental canals were obturated with a thick mix of pure ZOE through condensing with plugger manually. In the second experimental group, dental canals were obturated with a thin mix of ZOE by lentulo spiral. Coronal end of the canals were sealed with Coltosol and most of the root surface was covered with two layers of nail polish and one layer of stick wax, except for 2 mm of apical end of the root. Then samples were immersed in 2% methylene blue and sectioned longitudinally. Finally dye penetration was calculated under a stereomicroscope and results were analyzed by t-test. The mean value of dye penetration [microleakage] in first group was 2.92 mm and for the second group was about 4.83 mm so that the mean value in the first group was significantly lesser than that of the second group [P<0.001]. Because of high viscosity and thickness of ZOE, the hand-held technique [using plugger] had lesser microleakage and better apical seal which could be considered as the preferred technique in filling primary teeth canals

[In vitro comparison of the apical microleakage of laterally condensed gutta percha after using calcium hydroxide or cold ceramic as apical plug in open apex teeth]

The treatment of immature teeth with open apex by Gutta percha in one visit apexification requires an optimum material as apical barrier. One of the desirable properties of the apical barrier material is its sealing ability. This study was performed to compare the sealing ability of calcium hydroxide and a new experimental material [cold ceramic] when used as an apical barrier. Fifty extracted single canal human teeth were collected and stored in saline solution. The crowns were resected and by conventional step back method, canals were instrumented and then extended by Piso Reamer, so that, root ends were formed divergently. Samples were divided into two group including 23 teeth as study and 4 teeth as positive and negative control groups and then all teeth were mounted in a plaster cast. The two experimental materials [Cold ceramic and calcium hydroxide] were placed in the root ends for producing apical barrier, and canals were obturated with Gutta percha. The teeth in the positive and negative groups were obturated with Gutta percha, and in the negative group, cavit was placed at the end of root. In the 3 groups [calcium hydroxide, cold ceramic and positive group], all surfaces of the teeth were covered by two layers of the nail polish except 2 to 3 mm of the roots end and in the negative control group, samples were covered completely by two layers of the nail polish. Then, photographs of teeth were scanned and amount of leakage was calculated with the Photoshop software. The data were analyzed by t-test. Amount of cold ceramic leakage was less than calcium hydroxide and this difference was statistically significant [p=0.0001]. showed that apical plug with cold ceramic was more resistant than the apical plug with calcium hydroxide. The results of this study confirmed optimum sealing ability of the new experimental material for creating of apical barrier in one appointment apexification

Clinical evaluation of caries removal in primary molars using Carisolv and rotary instruments

Employing conservative procedures and considering patient comfort are of great importance, especially for dental treatment in paediatric patients. The aim of this study was to compare the efficacy of the Carisolv system with high-speed excavation of caries using rotary instruments, in primary molars. Twenty-five children with a mean age of 7.02 +/- 1.64 years were included in this clinical trial. Each patient had at least two contralateral primary molars with comparable caries and approximately equal-size access to lesions [N=50]. Caries were removed using the Carisolv system and rotary instruments. The efficiency of caries removal was judged on the basis of clinical criteria. Length of working time, need of local anesthesia, and level of patient cooperation were recorded for both methods. Statistical analysis was performed using the MCNemar and paired t-tests. The Carisolv and rotary systems removed 88% and 100% of the caries, respectively [p=0.0001], Working time with the chemomechanical method was prolonged when compared with the mechanical method [P =0.0001], but it did not negatively affect the childrens' cooperation. 92% of the patients found Carisolv treatment more acceptable than the highspeed excavation system. Furthermore, the chemomechanical method reduced the need for administration of local anesthesia for cavity preparations [0% versus 28%] [P=0.002]. Carisolv is an effective clinical alternative treatment for the removal of caries in primary molars. It is also more conservative of dental tissue and appears to be more comfortable for most patients

[Clinical and radiographic comparison of primary molars treated by formocresol and electrosurgical pulpotomy]

Pulpotomy is one of the routine methods for pulp therapy of primary teeth. At present it is a fact that ideal agent for this has not been discovered. The aim of this study was to compare the clinical and radiographic success rates of electrosurgical pulpotomy versus formocresol pulpotomy in human primary molar teeth. In this clinical trial study, pulpotomy was performed on 68 primary molars in children aged from 5 to 10 years. The teeth were treated using either a conventional formocresol [35 teeth], or electrosurgical technique [33 teeth]. Following the pulpotomy procedure, the teeth were evaluated regarding clinical and radiographic success for 3, 6 and 9 months periods. The teeth were evaluated clinically and radiographically for the presence of pain, abscess, fistula, mobility, internal and external resorption and radiolucency. Finally clinical and radiographic data were collected and analyzed with Fisher exact test using P<0.05 as the limit of significance. After 9 months follow up, the clinical and radiographic success rates for the electrosurgery group were 96% and 84% respectively and for formocresol group, 100% and 96.8% respectively. There were no statistically significant differences between the success rates for the two groups [P>0/05]. Although electrosurgical pulpotomy is a nonpharmacological and easy to use technique, further investigations with longer evaluation periods are suggested