It is narrated from the Mother of the Believers, Sayyidah Aishah (may Allah be pleased with her), that the Messenger of Allah (peace and blessings be upon him) said: "Praying with the siwak is seventy times greater than praying without the siwak."
This chain is not strong.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 161