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 (B) of dental floss (F) and an outlet port (4; 103) suitable to allow said user the progressive extraction of said dental floss (F) 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 spaced apart each other by a prefixed distance (D) and suitable to support a first progressive given length (L 1 ) of said dental floss (F) kept under tension, placing it in said prefixed distance (D) spacing apart said terminal tips ; - guide means , arranged at least in the upper outer wall of each of said terminal tips of said shaped arms (6, 7; 53, 54), suitable to receive a second progressive given length (L 2 ) of said dental floss (F); - 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 (F) 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 (B) of dental floss (F) and an outlet port (4; 103) suitable to allow said user the progressive extraction of said dental floss (F) 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 spaced apart each other by a prefixed distance (D) and suitable to support a first progressive given length (L 1 ) of said dental floss (F) kept under tension, placing it in said prefixed distance (D) spacing apart said terminal tips ; - guide means , arranged at least in the upper outer wall of each of said terminal tips of said shaped arms (6, 7; 53, 54), suitable to receive a second progressive given length (L 2 ) of said dental floss (F); - 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 (F) in order to favour effective and correct insertion thereof between two adjacent teeth, <EOS>