Antibacterial Effect of Metronidazole vs Chlorhexidine Solutions in Treatment of Root Canals of Primary Anterior Teeth.

AIM: The aim of this study was to evaluate and compare the antibacterial effect of 0.5% metronidazole, 2% chlorhexidine, and normal saline irrigant solutions against Enterococcus faecalis bacteria in the treatment of root canals of primary anterior teeth. MATERIALS AND METHODS: This study was carried out on sixty nonvital primary anterior teeth of Egyptian children diagnosed with (early childhood caries) ECC. These teeth were classified equally into three groups according to irrigation materials. A fresh sample was collected from each root canal after access opening before and 3 days after irrigation with the help of a paper point. The number of organisms (E. faecalis) before and after irrigation was compared for each group. RESULTS: The bacterial count of E. faecalis was decreased in all groups however, these differences were statistically insignificant where (p <0.05). CONCLUSION: Both 0.5% metronidazole and 2.0% chlorhexidine appeared to be superior against E. faecalis bacteria as endodontic irrigants in pulpectomy anterior primary teeth with higher antibacterial efficacy compared to saline. CLINICAL SIGNIFICANCE: The success of endodontic treatment depends on the removal of microbes, from the root canals and avoidance of reinfection thus; this study provides an insight on the effects of different irrigant solutions to further help dental practitioners in the endodontic management of primary dentition.

Evaluation of the Bond Strength of Universal Tray Adhesives on Silicone Impression Materials Using an Acrylic Tray.

AIM: To evaluate the bond strength of two commercially available universal tray adhesives on polyvinylsiloxane addition silicone and condensation silicone impression materials to an autopolymerizing polymethyl methacrylate acrylic tray material. MATERIALS AND METHODS: Sixty flat square specimens were fabricated from autopolymerizing polymethyl methacrylate tray material to which an eye hook was incorporated to serve as the point of attachment to a universal testing machine. A polyvinyl chloride (PVC) pipe of 15 mm diameter and 25 mm long was used to house the impression material, and a metal rod was inserted into two centered holes to provide retention that serves as the second point of attachment to the universal testing machine. The specimens were divided into 4 groups of 15 specimens each. The first and second groups of specimens were applied with Coltene and Zhermack universal tray adhesives and tested with addition silicone impression material. The third and fourth groups were coated with the above-mentioned adhesives, respectively, and tested with condensation silicone. Each specimen was then attached to the universal testing machine. The maximum force at which separation failure occurred was divided by the area of adhesion and recorded as the adhesive strength in MPa. RESULTS: A significant difference was observed between mean MPa values of Zhermack and Colten universal tray adhesives, where the F value of 1314.116 was found to be significant at 0.000 levels indicating that the Zhermack adhesive had higher MPa than Coltene adhesive. Impression material again indicated significant difference (F = 132.514; p = 0.000), where addition silicone had higher MPa value than condensation silicone. Also, the interaction between adhesive and impression material was found to be significant (F = 10.794; p = 0.002). CONCLUSION: The adhesive bond strength of Zhermack universal tray adhesive was higher compared to that of Coltene universal tray adhesive irrespective of the elastomeric impression material. It was also found that bond strength of Zhermack universal tray adhesive with addition silicone impression material was the highest and Coltene universal tray adhesive with condensation silicone impression material was the least of all the four groups. CLINICAL SIGNIFICANCE: Tray adhesives need to be applied to the tray to obtain an accurate and consistent impression. If there is a separation of impression materials from the tray, it may results in a distorted impression leading to poor final restorations.

Evaluation of Different Pretreatment Efficacy with Fluoride-releasing Material on Shear Bond Strength of Orthodontic Bracket: An In Vitro Study.

AIM: The aim of this study was to assess the efficacy of different pretreatments with fluoride-releasing material on shear bond strength (SBS) of orthodontic bracket. MATERIALS AND METHODS: A total of 60 human mandibular premolars were taken in this study. These samples were stored in periodically changed distilled water at room temperature so as to stop bacterial growth. All samples were randomized to three pretreatment groups: group I, acid etching; group II, fluoride varnish; group III, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste. Later, Transbond XT was applied on brackets made of stainless steel and brackets were centered buccally and then light-cured. The INSTRON universal machine was used to measure SBS. Based on the values, the adhesive remnant index (ARI) was estimated. RESULTS: The maximum SBS was seen in group III (18.84 µ 1.04), followed by group II (14.18 µ 0.23), and the minimum bond strength was found in group I (13.90 µ 1.22). The one-way analysis of variance (ANOVA) showed high statistically significant difference within the pretreatment groups. The pretreatment group comparisons showed statistically significant difference between group I vs group III and group II vs group III. Score 0 was more in group III [8 (40%)] followed by group II [4 (20%)] and group I [2 (10%)]. The lowest number of score 3 was found in CPP-ACP paste group. After comparing the ARI scores within the groups, the Chi-square test showed a probability of 0.001 which was statistically significant. CONCLUSION: Our study established that the CPP-ACP paste pretreatment improves the SBS of orthodontic bracket significantly followed by fluoride varnish and acid etching. CLINICAL SIGNIFICANCE: The bond strength of orthodontic brackets that were bonded should be adequate to resist orthodontic forces applied during treatment. The effect of the adhesive material to improve the adequate bond strength depends on the efficient pretreatment methods.