RESUMO
BACKGROUND: Paediatric-preformed zirconia crowns have been associated with several issues, primarily their inability to be crimped and the need for extensive tooth preparation. Additionally, the capacity to adjust the size, shape, and fit of these crowns is very limited. AIM: To evaluate and compare the fracture strength of four different types of dental crowns intended for paediatric patients. DESIGN: The fracture resistance of four types of paediatric crowns was evaluated using the universal testing machine; freshly extracted primary molars received one of the following: preformed zirconia crowns, custom-made computer-aided design and computer-aided manufacturing (CAD-CAM) zirconia crowns, custom-made CAD-CAM ceramic crowns, and custom-made CAD-CAM hybrid composite crowns. Data were statistically compared using the Kruskal-Wallis test followed by the Bonferroni test, and the level of significance was set at 5%. RESULTS: Results showed that there was a statistically significant difference among the four groups (p < .001). The highest value of fracture force was observed for the milled zirconia crown and the lowest for the prefabricated zirconia. CONCLUSION: The implementation of the CAD-CAM digital crown fabrication technique has the potential to address issues associated with preformed crowns in paediatric patients, particularly in terms of fracture resistance.
RESUMO
AIMS: To assess the fluoride concentration in water sources and its association with caries index in children living in Tripoli, Lebanon. MATERIALS AND METHODS: The concentration of fluoride was measured in tap and bottled water using ion chromatography. For tap water, eight water sources were evaluated before and after domestic distribution during June and November 2016. For bottled water, seven brands available on the market were tested. Caries were recorded in 402 children using DMFT/dmft indices. A questionnaire was distributed to parents to gather information about sociodemographic characteristics, the source of water consumed, the consumption of fluoride supplements, fluoridate salt, tea and sweets, and the frequency of toothbrushing. RESULTS: The fluoride concentration in tap water was not significantly different from the optimal concentration (p value > 0.05). However, the amount of fluoride in bottled water (0.14 ± 0.698 mg/L) was significantly lower than the optimal amount of fluoride recommended by the World Health Organization for decay prevention (0.5-1 mg/L) (p value < 0.001). The prevalence of caries was elevated in children aged 5 years (90.5%) and 12 years (89.6%). The carious indices were lower in children who consume tap water, tea, and fluoridated salt and those who consume less sweet. CONCLUSION: Additional studies covering all Lebanese regions should be performed to develop a national policy concerning fluoride-based scientific evidences. CLINICAL SIGNIFICANCE: Pedodontists should take in consideration the source of water consumed by the patient before prescribing a fluoride supplementation to avoid an overconsumption. They should promote effective oral hygiene methods and nutritional education and encourage regular tea consumption as an affordable source of fluoride to prevent caries.
