In vitro microleakage at the enamel and dentin margins of class II cavities of primary molars restored with a bulk-fill and a conventional composite.

OBJECTIVES: This study assessed the enamel and dentin margin microleakage of class II cavities of primary molars restored with a bulk-fill and a conventional composite. MATERIALS AND METHODS: In this in vitro, experimental study, standard class II cavities were created in the proximal surfaces of 60 extracted primary molars. The teeth were randomly divided into two groups, and restored with SonicFill bulk-fill and Filtek Z250 conventional composite along with Single Bond 2 adhesive. The teeth were coated with two layers of nail varnish to 1 mm around the restoration margins, and the apices were sealed with wax. The teeth underwent 1500 thermal cycles and incubated at 37°C for 24 h. They were then immersed in 1 M silver nitrate in the dark, rinsed with water, immersed in developing solution for 12 h, and exposed to fluorescent light. Next, they were mesiodistally sectioned, and digitally photographed under a stereomicroscope at ×10 magnification. The dye penetration depth was measured by a blind observer, and analyzed by the Mann-Whitney U test (α = .05). RESULTS: No significant difference existed in microleakage between the two composite groups at the enamel (p = .76) or dentin (p = .16) margins. In both composite groups, microleakage at the dentin margins was significantly greater than that at the enamel margins (p = .000). CONCLUSION: Considering the absence of a significant difference in microleakage, SonicFill bulk-fill composite can be used as an alternative to Filtek Z250 conventional composite for restoration of primary molars to benefit from its advantages such as simpler and faster application.

The effect of two calcium phosphate-containing agents on the enamel resistance of permanent molars to demineralization: An experimental study.

BACKGROUND: The main purpose of this experimental study was to determine the in vitro effects of two calcium phosphate-containing agents (Remin Pro® and GC Tooth mousse™) on the enamel resistance of permanent molars to demineralization. METHODS: Fifty extracted human third molars were randomly divided into four groups; that is the control group and three case groups treated with Remin Pro®, GC Tooth mousse™, and sodium fluoride gel. The three case groups were treated with 0.25 ml of the paste associated with each experimental group for 5 min, kept in fluoride-free artificial saliva, and incubated at 37°C for 28 days. After the treatment regimen, 10 samples of each case group were subjected to demineralization using an acetic acid-containing solution, and remineralization using a remineralizing solution. The morphology of enamel was observed via scanning electron microscopy and their enamel calcium/phosphorus (Ca/P) ratios were measured before/after the demineralization cycle with energy-dispersive X-ray analysis. Data were statistically analyzed using one-way analysis of variance and post hoc Tukey tests. RESULTS: The enamel Ca/P ratios in the case study groups were significantly higher than that of the control group before/after the demineralization regimen (p < .0001). However, the ratios were not significantly different between the case study groups after the treatment regimen and demineralization cycle (p > .05). CONCLUSION: The outcomes of the current study indicated that all three agents seemed to increase the enamel resistance of permanent molar teeth to demineralization.

Shear Bond Strength of Self-Adhesive Flowable Composite, Conventional Flowable Composite and Resin-Modified Glass Ionomer Cement to Primary Dentin.

OBJECTIVES: This study aimed to compare the shear bond strength (SBS) of self-adhesive and conventional flowable composites and resin-modified glass-ionomer cement (RMGIC) to primary dentin. MATERIALS AND METHODS: In this in vitro, experimental study, the buccal surface of 48 primary canine and first molar teeth was longitudinally sectioned to expose dentin. The teeth were randomly divided into three groups (n=16) of 37.5% phosphoric acid+ OptiBond+ Premise Flow composite (group 1), Vertise Flow composite (group 2) and RMGIC (group 3). A plastic cylindrical mold was placed on the exposed dentin and filled with restorative materials. The samples were then immersed in distilled water at 37°C for 24 hours, subjected to 1000 thermal cycles between 5-55°C and underwent SBS test. The mode of failure was determined under a stereomicroscope. Data were analyzed using one-way ANOVA and Tukey's test. RESULTS: A significant difference was noted in SBS of the groups (P<0.05). The SBS of conventional flowable composite was significantly higher that of RMGIC and self-adhesive flowable composite (P<0.05). The difference in SBS of RMGIC and self-adhesive flowable composite was not significant (P>0.05). Failure at the dentin-restoration interface (adhesive failure) had the highest frequency in groups 1 and 2. The frequency of adhesive failure was 100% in group 3. CONCLUSION: Within the limitations of this study, the conventional flowable composite yielded the highest SBS to primary dentin. Self-adhesive flowable composite and RMGIC showed the lowest SBS with no significant difference with each other.

Microleakage of a Self-Adhesive Flowable Composite, a Self-Adhesive Fissure Sealant and a Conventional Fissure Sealant in Permanent Teeth with/without Saliva Contamination.

OBJECTIVES: Application of fissure sealants is a practical method for prevention of occlusal pit and fissure caries. Microleakage is an important factor affecting the success of fissure sealant treatment. This study aimed to assess the microleakage of a self-adhesive flowable composite, a self-adhesive fissure sealant and a conventional fissure sealant in permanent teeth with/without saliva contamination. MATERIALS AND METHODS: This in vitro, experimental study evaluated 108 extracted human third molars, which were randomly divided into six groups (n=18) of control, Denu-Seal conventional fissure sealant applied on etched enamel with/without saliva contamination, Vertise Flow self-adhesive flowable composite applied on rinsed and dried enamel with/without saliva contamination and Prevent Seal self-adhesive fissure sealant applied on rinsed and dried enamel with/without saliva contamination. Microleakage was assessed using the dye penetration technique and subsequent observation of samples under a stereomicroscope. Data were analyzed using the Kruskal-Wallis and Tukey's test. RESULTS: Microleakage of the conventional fissure sealant with/without saliva contamination was significantly lower than that of other groups (P<0.05). CONCLUSION: Microleakage of the conventional fissure sealant is less than that of self-adhesive fissure sealant and self-adhesive composite, irrespective of saliva contamination.

Assessment of Periodontal Parameters Following the Use of Fixed and Removable Space Maintainers in 6-12-year Olds.

AIM: Placement of fixed space maintainer (FSM) and removable space maintainer (RSM) may increase the risk of gingivitis in children. This study aimed to assess the effect of using FSMs and RSMs on periodontal parameters in 6-12-year olds. MATERIALS AND METHODS: This interventional prospective study was conducted on systemically healthy 6-12-year olds (mean age of 8 years) presenting at the Department of Pediatrics, Tehran University requiring space maintainers. The probing pocket depth (PPD), bleeding on probing (BOP), and gingival index (GI) were recorded at the baseline and 6 months after using space maintainers in the abutment teeth in patients with fixed space maintainers and in the tooth with the Adams clasp in children with removable space maintainers as well as the same teeth in the opposing jaw/quadrant as controls. RESULTS: A significant increase in PPD was noted in distolingual and mesiolingual sites at 6 months after placement of FSM (p < 0.05). This increase was not significant for RSM at any site. A significant increase in GI and BOP was also noted at 6 months after placement of FSM and RSM (p < 0.05). Caries index did not show a significant change in FSM but caries index significantly increased following the use of RSM. CONCLUSION: BOP and GI increase following placement of FSM and RSM, and PPD increases in distolingual and mesiolingual areas of the banded tooth. HOW TO CITE THIS ARTICLE: Hosseinipour ZS, Poorzandpoush K, Heidari A, et al. Assessment of Periodontal Parameters Following the Use of Fixed and Removable Space Maintainers in 6-12-year Olds. Int J Clin Pediatr Dent 2019;12(5):405-409.

Effect of addition of Nano hydroxyapatite particles on wear of resin modified glass ionomer by tooth brushing simulation.

BACKGROUND: Recently, incorporation of nanohydroxyapatite (NHA) has been suggested to improve the mechanical properties of glass ionomers (GIs). This study aimed to assess the effect of addition of NHA on wear of resin modified glass ionomer (RMGI) by tooth brushing simulation. MATERIAL AND METHODS: In this in vitro, experimental study, NHA in 1, 2, 5, 7 and 10wt% concentrations was added to Fuji II LC RMGI powder, and 48 samples (5×5mm) in five experimental and one control group (n=8) were fabricated. After polishing, cleaning and incubation at 37°C for three weeks, the samples were weighed and subjected to tooth brushing simulation in a toothpaste slurry according to ISO14569-1. Then, they were weighed again and the weight loss was calculated. The data were analyzed using one-way ANOVA and Tukey's test. RESULTS: The highest and the lowest weight loss was found in the 0% NHA (-1.052±0.176) and 5% NHA (-0.370±0.143) groups, respectively. Wear was significantly higher in 0% NHA group (P<0.05). No difference was detected in wear between 2 and 5wt% NHA or among 1, 7 and 10wt% NHA groups. Significant differences were noted in wear between 2 and 5wt% NHA and 1, 7 and 10wt% NHA groups (P<0.001). CONCLUSIONS: Incorporation of up to 10wt% of NHA increases the wear resistance of Fuji II LC RMGI. This increase was the highest when 2 and 5wt% NHA were added. Key words:Glass ionomer, hydroxyapatites, nanoparticles, dental restoration wear.