【单选题】
男性,27岁,左下后牙牙龈反复肿胀疼痛3个月,检查:<img src="https://nimg.ppkao.com/2015-09/yeni/2015091616304617450.jpg?sign=03124d2cf7c53a46ae675cec101afe4b&t=62d0ae61" />缺失,<img src="https://nimg.ppkao.com/2015-09/yeni/201509161630562781.jpg?sign=f4a1d50f101940c7ae755148ee5e3f4a&t=62d0ae61" />近中倾斜,<img src="https://nimg.ppkao.com/2015-09/yeni/2015091616310493954.jpg?sign=574744f4485dccb2ddb737e28100e736&t=62d0ae61" />间邻面接触关系不佳,该处牙龈肿胀,探诊易出血,探诊深度4mm,无自发出血现象。牙龈反复肿痛的原因最可能是()
A、血液性疾病
B、食物嵌塞
C、牙龈瘤
D、增生性龈炎
E、口呼吸