حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا شَرِيكٌ، عَنِ الْمِقْدَامِ بْنِ شُرَيْحِ بْنِ هَانِئٍ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، قَالَ قُلْتُ أَخْبِرِينِي بِأَىِّ، شَىْءٍ كَانَ النَّبِيُّ ـ صلى الله عليه وسلم ـ يَبْدَأُ إِذَا دَخَلَ عَلَيْكِ قَالَتْ كَانَ إِذَا دَخَلَ يَبْدَأُ بِالسِّوَاكِ ‏.‏

It was narrated from Miqdam bin Shuraih bin Hani' that his father said: "I said to 'Aishah: 'Tell me, what was the first thing that the Messenger of Allah did when he entered upon you?' She said: 'The first thing he would do would be to use the tooth stick.'" Translation Not Available

Book Ref: Sunan Ibn Majah Book 1 Hadith 290
Web Ref:  Sunan Ibn Majah Vol 1 Book 1 Hadith 290