What is the obturating material of choice for primary teeth after a complete pulpectomy?

The ideal obturating material for primary teeth after a complete pulpectomy is zinc oxide and eugenol cement. This material is favored due to its biocompatibility and the ability to provide a good seal within the root canal space. Its properties allow for effective filling while maintaining the integrity of the tooth structure. Zinc oxide and eugenol cement also possess antibacterial effects that can help to prevent reinfection following the treatment.

In the context of other options, it's important to note that although some may have beneficial qualities, they do not match zinc oxide and eugenol in terms of overall suitability for primary teeth after pulpectomy. For instance, zinc phosphate cement and the formocresol combination are not commonly used for obturating primary teeth due to potential irritative and toxic effects associated with formocresol. Meanwhile, quick setting hydroxide cement primarily serves as a temporary measure rather than a definitive obturation material. Gutta-percha, while effective in permanent teeth, is generally not recommended for primary teeth due to its rigidity and the differing root canal anatomy in primary teeth which can make it more challenging for complete sealing. Therefore, zinc oxide and eugenol cement remains the superior choice for this procedure.