ENOfficial
It was narrated from Al-Miqdam - Abu Shuraih - that his father said: "I said to 'Aishah: 'What did the Prophet (ﷺ) start with when he entered his house?' She said: 'The Siwak.'"
Source: sunnah.com
Other translations
Arabic
أَخْبَرَنَا عَلِيُّ بْنُ خَشْرَمٍ، قَالَ حَدَّثَنَا عِيسَى، - وَهُوَ ابْنُ يُونُسَ - عَنْ مِسْعَرٍ، عَنِ الْمِقْدَامِ، - وَهُوَ ابْنُ شُرَيْحٍ - عَنْ أَبِيهِ، قَالَ قُلْتُ لِعَائِشَةَ بِأَىِّ شَىْءٍ كَانَ يَبْدَأُ النَّبِيُّ صلى الله عليه وسلم إِذَا دَخَلَ بَيْتَهُ قَالَتْ بِالسِّوَاكِ .
sunnah.com