Effect of Light Curing on Silver Diamine Fluoride in Primary Incisors: A Microscopic Ex Vivo Study.

Purpose: To determine the effect of a dental curing light on the penetration depth of silver diamine fluoride (SDF), dentin hardness, and silver and fluoride ion precipitation into cavitated carious lesions. Methods: SDF was applied on 16 primary incisors extracted due to caries extending into dentin. Teeth were divided into two groups: (1) control group, was not light-cured; and (2) test group, was light-cured. A scanning electron microscope, and OmniMet software were used to measure penetration depth, dentin hardness, and ion precipitation. Wilcoxon's ranksum test was used for statistical analysis. Results: All samples in both groups showed SDF penetration beyond the carious lesion and into sound dentin. The penetration depth into sound dentin was 70 µm further without the dental curing light it (P<0.001). Silver precipitation in infected dentin with the dental curing light was approximately 2.6 times greater than without it (P=0.02). Dentin hardness of infected dentin was 26 percent more with the dental curing light (P=0.04). Conclusions: Applying a dental curing light during silver diamine fluoride treatment of carious lesions induces more silver ion precipitation in infected dentin, increases its hardness, and, perhaps because more silver stays in the infected dentin, less SDF penetrates into sound dentin.

Relationship of Lower Lingual Arch Appliance Use and Impaction of Second Molars: A Retrospective Study.

Purpose: The purpose of this study was to determine the prevalence of permanent mandibular second molar impaction in pediatric patients treated with a lower lingual holding arch (LLHA) to maintain lower arch perimeter. Methods: In this retrospective study, 259 radiographs of nine- to 17-year-old pediatric patients were examined for permanent mandibular second molar impaction. A total of 127 patients with LLHA were compared to a control group of 132 patients who had not received LLHA. Other independent variables (sex and treatment age) were also tested for their value as predictors of impaction difficulty. For statistical analysis, the chi-square test was used. Logistic regression analysis was used to determine the statistical significance of the possible predictors of second molar impaction. Results: The mean age of the subjects was 9.2±1.7 (standard deviation) years old. The prevalence of permanent mandibular second molar impaction was 7.1 percent in patients with LLHA compared to 1.5 percent in the control group. The LLHA group had a likelihood of second molar impaction 6.53 times higher than controls after controlling for age. The relationship was significant with P-value of 0.021. Conclusions: The lower lingual holding arch is associated with an increased risk of second molar impaction in patients nine to 17 years old.