Use-and-throw-away or disposable oral care tool (1; 50; 100) for tensioned dental floss comprising: - a hollow handle portion (2; 51; 101) at the user's disposal in which a housing chamber, suitable to receive a spool of dental floss and an outlet port (4; 103) suitable to allow said user the progressive extraction of said dental floss from said hollow handle portion (2; 51; 101), are defined; - a fork (5; 52) formed by a couple of shaped arms (6, 7; 53, 54), projecting upwardly from said hollow handle portion (2; 51; 101), provided with respective terminal tips (8, 9) spaced apart each other by a prefixed distance and suitable to support a first progressive given length (L 1) of said dental floss kept under tension, placing it in said prefixed distance spacing apart said terminal tips (8, 9); - guide means, arranged at least in the upper outer wall (8a, 9a) of each of said terminal tips (8, 9) of said shaped arms (6, 7; 53, 54), suitable to receive a second progressive given length (L 2) of said dental floss; - tensioning means (11; 55), associated externally with said hollow handle portion (2; 51; 101) and/or said fork (5; 52), suitable to allow to said user to tension at least said first given length (L 1) of said dental floss in order to favour effective and correct insertion thereof between two adjacent teeth, wherein said hollow handle portion (2; 51; 101), said fork (5; 52), said guide means and said tensioning means (11; 55) are made in one piece and monolithic each other forming a single reinforced structural body obtained directly during the production phase by molding and having an at least partially box-shaped structure in a part defining said hollow handle portion (2; 51; 101), and said reinforced structural body includes a first box-structured portion and a second box-structured portion coupled each other on one side through an elastically yielding union edge, monolithic to said first portion and said second portion and defining a linear rotation axis suitable to allow the mutual rotation of said first portion and said second portion, and on the other side through connecting means, monolithic to said first portion and said second portion and suitable to determine at least the hermetic closure of said at least partially box-shaped structure of said reinforced structural body, characterized in that said connecting means are of the fixed type in such a way that said first portion is firmly and definitively coupled with said second portion. - a hollow handle portion (2; 51; 101) at the user's disposal in which a housing chamber, suitable to receive a spool of dental floss and an outlet port (4; 103) suitable to allow said user the progressive extraction of said dental floss from said hollow handle portion (2; 51; 101), are defined; - a fork (5; 52) formed by a couple of shaped arms (6, 7; 53, 54), projecting upwardly from said hollow handle portion (2; 51; 101), provided with respective terminal tips (8, 9) spaced apart each other by a prefixed distance and suitable to support a first progressive given length (L 1) of said dental floss kept under tension, placing it in said prefixed distance spacing apart said terminal tips (8, 9); - guide means, arranged at least in the upper outer wall (8a, 9a) of each of said terminal tips (8, 9) of said shaped arms (6, 7; 53, 54), suitable to receive a second progressive given length (L 2) of said dental floss; - tensioning means (11; 55), associated externally with said hollow handle portion (2; 51; 101) and/or said fork (5; 52), suitable to allow to said user to tension at least said first given length (L 1) of said dental floss in order to favour effective and correct insertion thereof between two adjacent teeth,