Question: what did romans use to clean their teeth
[{'answer': 'twigs', 'provenance': [{'wikipedia_id': '9812712', 'title': 'Tooth brushing', 'start_paragraph_id': 4, 'start_character': 84, 'end_paragraph_id': 4, 'end_character': 89, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '9812712', 'title': 'Tooth brushing', 'start_paragraph_id': 4, 'start_character': 0, 'end_paragraph_id': 4, 'end_character': 329, 'bleu_score': 0.9209994736331291, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5270082444092144656}, 'section': 'Section::::History.\n'}]}]