loosening

an occurrence of control or strength weakening; "the relaxation of requirements"; "the loosening of his grip"; "the slackening of the wind"

अजायबघर नौ बजे खुलता है और पाँच बजे बद हो जाता है|

Such deposits, if not removed by scaling, cause infection and loosening of the gums, ultimately leading to pyorrhoea and tooth loss.