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.

Clinical Evaluation for Space Maintainer after Unilateral Loss of Primary First Molar in the Early Mixed Dentition Stage.

Background and Objectives: Controversy exists regarding the need for a space maintainer after early unilateral loss of a primary first molar. This study aimed to assess the need for a space maintainer after unilateral loss of a primary first molar in the early mixed dentition period. Materials and Methods. In this cross-sectional study, fifty children between 6 and 8 years who had lost a primary first molar unilaterally later than 6 months ago were randomly selected. Midline deviation, molar and canine relationships at both sides, facial growth pattern, and the amount of space loss were all assessed. Data were analyzed using SPSS version 25 via the one-sample t-test, paired t-test, and linear regression (alpha = 0.05). Results. The mean amount of space loss was 1.36 ± 0.78 mm (1.32 mm in the maxilla and 1.40 mm in the mandible). Time since tooth extraction and facial pattern had significant correlations with space loss (P < 0.05). Conclusion. In this particular age group, it is imperative to precisely assess the related factors such as the facial pattern and time since tooth extraction to decide about the placement of a space maintainer for a prematurely lost primary first molar.

Association between Dental Caries and Passive Smoking and Its Related Factors in Children Aged 3-9 Years Old.

AIMS: Dental caries is the most common chronic and infectious childhood disease. Several studies have investigated the side effects of cigarette smoke on oral health. Caries appear to be higher in children exposed to environmental cigarette smoke, but this relationship has not yet been established. The purpose of this study was to investigate the relationship between dental caries and passive smoker children aged 3-9 years old. MATERIALS AND METHODS: This descriptive analytical study was performed on 75 children aged from 3 to 9 years. The study included two groups (first group: control, second group: passive smoker). Demographic data, frequency of toothbrushing and using toothpaste, sugar consumption, and number of dental visits were recorded in a questionnaire. Then, the children were examined, and dmft and DMFT index and plaque index were recorded. Children's saliva was then collected and sent to the laboratory for determination of cotinine levels. Then, the relationship between passive smoker and caries index and other factors were statistically analyzed. RESULTS: Studying dmft and DMFT, it was found that except for component M (Missing) which was zero in both groups, the other components of these two indices were significantly higher in the group exposed to passive smoker. Plaque index and salivary cotinine level were also significantly different in the two groups and were lower in the control group. CONCLUSION: According to the results of this study, children exposed to passive smoker have a higher rate of caries than other children. It seems that it is primarily due to its effect on increasing plaque accumulation and then the effect of passive smoker on the physiological structures of the mouth and so on. CLINICAL SIGNIFICANCE: We can perform preventive care for children if we know that passive smoking may cause more dental caries. HOW TO CITE THIS ARTICLE: Mosharrafian S, Lohoni S, Mokhtari S. Association between Dental Caries and Passive Smoking and Its Related Factors in Children Aged 3-9 Years Old. Int J Clin Pediatr Dent 2020;13(6):600-605.

Fracture Resistance of a Bulk-Fill and a Conventional Composite and the Combination of Both for Coronal Restoration of Severely Damaged Primary Anterior Teeth.

OBJECTIVES: This study aimed to compare the fracture resistance of a bulk-fill and a conventional composite and a combination of both for coronal restoration of severely damaged primary anterior teeth. MATERIALS AND METHODS: In this in vitro experimental study, 45 primary anterior teeth were randomly divided into three groups. After root canal preparation, the canals were filled with Metapex paste such that after the application of 1 mm of light-cure liner, 3 mm of the coronal third of the canal remained empty for composite post fabrication. Filtek Z250 conventional composite was used in group 1, Sonic-Fill bulk-fill composite was used in group 2 and Sonic-Fill with one layer of Filtek Z250 as the veneering were used in group 3. Adper Single Bond 2 was used in all groups. The teeth were thermocycled, and fracture resistance was measured by a universal testing machine. The mode of fracture was categorized as repairable or irreparable. Data were analyzed using one-way ANOVA. RESULTS: The mean fracture resistance was 307.00±74.72, 323.31±84.28 and 333.30±63.96 N in groups 1 to 3, respectively (P=0.55). The mean fracture strength was 14.53±2.98, 15.08±2.82 and 15.26±3.02 MPa in groups 1 to 3, respectively (P=0.77). The frequency of repairable mode of failure was 80% for the conventional, 73.6% for the bulk-fill and 80% for the bulk-fill plus conventional group, with no significant difference (P>0.05). CONCLUSION: Bulk-fill composites can be used for coronal reconstruction of severely damaged primary anterior teeth similar to conventional composites to decrease the treatment time in pediatric patients.

Microleakage of Two Bulk Fill and One Conventional Composite in Class II Restorations of Primary Posterior Teeth.

OBJECTIVES: This study aimed to assess and compare the microleakage of two bulk fill and one conventional composite in class II restorations of primary posterior teeth. MATERIALS AND METHODS: This in vitro, experimental study was conducted on 60 primary mandibular second molars, which were randomly divided into three groups. Standard class II cavities were prepared in teeth and restored with 3M bulk fill composite in group 1, SonicFill bulk fill composite in group 2 and Z250 conventional composite in group 3. Single Bond 2 bonding agent was used in all cavities. The teeth were then thermocycled and immersed in 1M silver nitrate solution. The teeth were then mesiodistally sectioned and evaluated under a stereomicroscope at×10 magnification. Dye penetration depth was recorded in microns and data were analyzed using one-way ANOVA. RESULTS: The mean (± standard deviation) dye penetration depth in the gingival margins was 543±523µm, 343±290µm and 597±590µm for 3M bulk fill, SonicFill and Z250 conventional composite, respectively. These values were 214±93µm, 302±127µm and 199±145µm in the occlusal margins, respectively. The three groups were not significantly different in terms of occlusal or gingival microleakage (P>0.05), but gingival margins showed significantly higher microleakage than occlusal margins in all three groups (P<0.05). CONCLUSIONS: Bulk fill composites are not significantly different from conventional composites in terms of microleakage.

Effect of Etching Time and Preparation on Push-Out Bond Strength of Composite to Intracanal Dentin of Primary Anterior Teeth.

OBJECTIVES: This in-vitro study aimed to compare the push-out bond strength of composite to prepared and unprepared intracanal dentin using a 5th generation bonding agent in primary anterior teeth after etching for seven and 15 seconds. MATERIALS AND METHODS: Sixty primary anterior teeth were randomly divided into four groups. In groups one and two, intracanal dentin remained intact while in groups three and four it was prepared using a #5 round bur and low-speed handpiece. Single Bond 2 was used in groups one and three after 15 seconds and in groups two and four after seven seconds of etching with phosphoric acid. After restoring with composite resin and incubation, the specimens were subjected to push-out bond strength test. Data were analyzed using two-way ANOVA and Kaplan Meier curves. RESULTS: The mean bond strength was not significantly different between seven and 15 seconds etching times (P=0.198). Dentin preparation had no significant effect on the mean bond strength (P=0.838). The interaction effect of etching time and dentin preparation was not significant either (P=0.680). CONCLUSIONS: Decreasing the etching time from 15 to seven seconds and preparation of intracanal dentin had no significant effect on push-out bond strength of composite to intracanal dentin of primary anterior teeth.

Comparison of Push-Out Bond Strength of Two Bulk-Fill and One Conventional Composite to Intracanal Dentin in Severely Damaged Primary Anterior Teeth.

OBJECTIVES: This study sought to compare the push-out bond strength of two bulk-fill and one conventional composite to intracanal dentin in primary anterior teeth. MATERIALS AND METHODS: This in vitro, experimental study was conducted on 39 primary anterior teeth, which were randomly divided into three groups. After cleaning and shaping, the root canals were filled with Metapex in such a way that after the application of 1mm light-cure liner on top of it, the coronal 3mm of the canal remained empty for composite post space. Z250 conventional composite was used in group 1 and SonicFill and Filtek bulk-fill composites along with Single Bond 2 were used in groups 2 and 3, respectively. The samples were subjected to thermocycling. One-millimeter thick sections were made of the mid-root and subjected to push-out bond strength test. Mode of failure was determined under a stereomicroscope at ×25 magnification. The data were analyzed using one-way ANOVA. RESULTS: The mean (±standard deviation) push-out bond strength was 11.40±4.23MPa, 10.94±6.69MPa and 8.79±4.12MPa in the conventional, SonicFill and Filtek groups, respectively. The difference in this regard among the three groups was not statistically significant (P=0.397). CONCLUSIONS: Based on the results, bulk-fill composites, similar to conventional types, can be successfully used for the fabrication of composite intracanal posts in primary teeth to decrease the treatment time in children.