JP4076403B2 - toothbrush - Google Patents

Description

【０００７】
また、本発明の歯ブラシは、前記中央主ブリッスルの平均植毛高さが、各々の前記外側領域における外側主ブリッスルの平均植毛高さよりも０．１〜４．０ｍｍ高く、前記各中央主ブリッスルのかたさ理論値Ｔ _in 及び前記各外側主ブリッスルのかたさ理論値Ｔ _out から算定した、前記中央帯状領域の全体のかたさと前記外側領域の全体のかたさとの比（かたさの内外比）が１．０５〜３．０であることが好ましい。
【０００８】
ここで、本願において、「主ブリッスル」は、図４（ａ），（ｂ）にモデル化して示すように、植毛台５０に植設された複数本のブリッスル５１の先端を平坦な面５２に当接させて植毛台５０の後側から３００ｇの荷重Ｐを垂直に負荷しつつ刷掃した際に、平坦な面５２に先端が接触するブリッスル５１ａを意味するものであり、３００ｇの荷重Ｐが垂直に負荷されて植毛台５０が変位ｓだけ移動してもその先端が平坦な面５２に当接しない、最も長いブリッスルと５１ａとの毛丈の段差が変位ｓよりも大きいブリッスル５１ｂを除いて考える趣旨である。
【０００９】
また、本願において、「ブリッスルのかたさ理論値Ｔ」は、図５に示す梁の撓み式に関する模式図において、梁を円形断面のものとして下記（式３）によって得られた撓み（ｖ）の逆数（１／ｖ）として求められる値であって、下記（式４）によって表されるものである。
【００１０】
【数３】

【００１１】
【数４】

【００１２】
さらに、本願において、中央主ブリッスルは、歯ブラシの軸方向と平行な３ｍｍ幅の中央帯状領域に植設されてその先端が当該中央帯状領域の上方に位置する主ブリッスルであって、毛束が中央帯状領域と外側領域との間の区画線に跨って植設されている場合には、当該区画線で分けて中央帯状領域側に配置された主ブリッスルを中央主ブリッスルとし、外側領域側に配置された主ブリッスルを外側主ブリッスルとするものである。
【００１３】
なお、中央帯状領域の幅を３ｍｍとしたのは、後述する歯垢除去率のモデル試験により、中央帯状領域における中央主ブリッスルと各外側領域における外側主ブリッスルとの平均植毛高さの差である凸型の内外段差と、中央主ブリッスルと各外側主ブリッスルのかたさの内外比とを統一した条件下で、中央帯状領域の幅を変化させつつ歯垢除去率に対するパラメータを調べた結果、中央帯状領域の幅を３ｍｍとすることによって歯垢除去率の変化が特に顕著に現れたことによるものである。
【００１４】
そして、本発明の歯ブラシによれば、中央主ブリッスルの平均植毛高さが、前記各外側領域における外側主ブリッスルの平均植毛高さよりも大きく、且つ前記各中央主ブリッスルのかたさ理論値Ｔ _in 及び前記各外側主ブリッスルのかたさ理論値Ｔ _out から算定した、前記中央帯状領域の全体のかたさと前記外側領域の全体のかたさとの比（かたさの内外比）が１よりも大きくなっているので、外側主ブリッスルよりも毛丈の長い中央主ブリッスルの毛先が刷掃時に歯間部に容易且つスムーズに入り込んで効率良く歯間部の刷掃をおこなうことが可能になる。
【００１５】
また中央主ブリッスルの植毛高さの方が外側主ブリッスルの植毛高さよりも大きくなっているにもかかわらず、中央主ブリッスルの全体のかたさが外側主ブリッスルの全体のかたさよりもかたくなっていることにより、中央主ブリッスルは、コシが弱くなったり撓みすぎることがなく、これによって歯垢の除去効果を充分に発揮することが可能になる。
【００１６】
すなわち、中央帯状領域における中央主ブリッスルと外側領域における外側主ブリッスルとの平均植毛高さの差である内外段差を凸型にすると共に当該内外段差を大きくすることと、かたさの内外比を大きくすることとは、いずれも歯間部の歯垢除去率を向上させる要因になるものと考えられるが、通常は内外段差を凸型にすると、かたさの内外比は１以下になる。一方、本発明によれば、中央主ブリッスルと外側主ブリッスルとによる内外段差が凸型となっているにもかかわらず、かたさの内外比が１よりも大きく保持されていることにより、これらの相乗効果によって、優れた歯間部の歯垢の除去効果が得られることになる。
【００１７】
なお、本発明によれば、中央主ブリッスルと外側主ブリッスルとの内外段差を凸型にすると共に、かたさの内外比が１よりも大きくなるように調整する手段としては、例えば各主ブリッスルの毛の太さを調整する方法、各主ブリッスルの毛の材質を調整する方法等を採用することができる。
【００１８】
また、本発明によれば、中央主ブリッスルと各々の外側領域における外側主ブリッスルとの平均植毛高さの差である凸型の内外段差を０．１〜４．０ｍｍとし、かたさの内外比を１．０５〜４．０とすることにより、さらに確実に歯垢の除去効果を向上させることが可能になると共に、使用時における歯間到達感の格段の向上と、外側領域に必然的にやわらかい毛を配置することによる歯肉為害性の低減が可能になる。
【００１９】
そして、凸型の内外段差の範囲を０．１〜４．０ｍｍとすれば、かたさの内外比が１．０５〜４．０の範囲で、少しでも段差があれば歯垢除去効果が向上することになる。凸型の内外段差が４．０ｍｍ以上では、外側のブリッスルが短かすぎて内側のブリッスルの外側へのはみ出しの阻止効果が低減することになり、歯垢除去効果が低下することになる。
【００２０】
また、かたさの内外比の範囲を１．０５〜４．０とすれば、凸型の内外段差が０．１〜４．０ｍｍの範囲で、内側が外側より少しでもかたくなって歯垢除去効果が向上することになる。かたさの内外比が４．０を超えると内側と外側のブリッスルのかたさの差が大きすぎて歯垢除去効果が低減することになる。かたさの内外比が４．０を超えた場合には、内側のブリッスルが適度なかたさとなるように、例えばＴ_inの総和ΣＴ_in＝０．０５〜０．２０（Ｅはナイロンブリッスルの弾性率を１８０ｋｇ／ｍｍ²、ｋ＝１として計算）としても、外側の毛がやわらかすぎて内側のブリッスルの外側へのはみ出しを阻止できなくなって歯垢除去効果が低下し、外側のブリッスルを適度なかたさとしても、内側の毛がかたすぎてブラッシングの際に歯ぐきを傷つけるという問題が生じることになる。
【００２１】
【発明の実施の形態】
図１に示す本発明の好ましい第１実施形態に係る歯ブラシ１０は、把持部（図示せず）と植毛台１１とこれらを連結する首部１２とからなる歯ブラシ本体の植毛台１１に形成した複数の植毛穴１３に、複数本のブリッスル１４ａ，１４ｂ，１４ｃ，１４ｄを束ねてなる毛束（タフト）１５ａ，１５ｂ，１５ｃ，１５ｄを各々植毛（植設）することによって構成されている。
【００２２】
本第１実施形態の歯ブラシ１０によれば、歯ブラシ本体は、例えばポリプロピレン、ＡＢＳ樹脂等の合成樹脂からなる公知のもので、その植毛台１１の平坦な植毛面には、直径が１．２ｍｍの円形断面の植毛穴１３が千鳥状に整列されて、植毛面の略全域に亘って縦横４０箇所に分散配置されていると共に、これらの植毛穴１３には、図１において白丸で略示される第１毛束１５ａが１２箇所に、黒丸で略示される第２毛束１５ｂが２箇所に、丸に十字を描いて略示される第３毛束１５ｃが８箇所に、二重丸で略示される第４毛束１５ｄが１８箇所に各々植毛されている。
【００２３】
また、各毛束１５ａ，１５ｂ，１５ｃ，１５ｄを構成するブリッスル１４ａ，１４ｂ，１４ｃ，１４ｄは、ナイロン等の合成樹脂からなる例えば６〜９milの太さを有するフィラメント材であって、これを例えば十数本〜数十本束ねることによって各毛束１５ａ，１５ｂ，１５ｃ，１５ｄが形成される。
【００２４】
本第１実施形態によれば、植毛台１１の植毛面を歯ブラシ１０の軸方向Ｘと平行な一対の区画線１８によって３ｍｍ幅の中央帯状領域１６とこれの両側の一対の外側領域１７とに区画した際に、中央帯状領域１６には１２箇所の第１毛束１５ａと２箇所の第２毛束１５ｂとが植毛され、各外側領域１７には、各々４箇所の第３毛束１５ｃと９箇所の第４毛束１５ｄとが植毛されることになる。なお、本第１実施形態によれば、中央帯状領域１６と外側領域１７との間の区画線１８に隣接して配置される第１毛束１５ａ、第３毛束１５ｃ、第４毛束１５ｄの周縁部に位置するブリッスル１４ａ，１４ｃ，１４ｄの一部が、中央帯状領域１６側又は外側領域１７側にはみ出して植毛されている。
【００２５】
そして、本第１実施形態によれば、第１毛束１５ａは、太さが９mil（０．２２９ｍｍ）の第１ブリッスル１４ａを１６本束ねて構成されており、各第１ブリッスル１４ａは植毛面から１１．５ｍｍの毛丈で植毛されている。また第２毛束１５ｂは、太さが８mil（０．２０３ｍｍ）の第２ブリッスル１４ｂを２０本束ねて構成されており、各第２ブリッスル１４ｂは植毛面から１１．５ｍｍの毛丈で植毛されている。さらに、第３毛束１５ｃは、太さが７mil（０．１７８ｍｍ）の第３ブリッスル１４ｃを２６本束ねて構成されており、各第３ブリッスル１４ｃは植毛面から１０．５ｍｍの毛丈で植毛されている。さらにまた、第４毛束１５ｄは、太さが６mil（０．１５２ｍｍ）の第４ブリッスル１４ｄを３４本束ねて構成されており、各第４ブリッスル１４ｄは植毛面から１０．５ｍｍの毛丈で植毛されている。
【００２６】
これらによって、本第１実施形態の歯ブラシ１０によれば、各毛束１５ａ，１５ｂ，１５ｃ，１５ｄを構成するブリッスル１４ａ，１４ｂ，１４ｃ，１４ｄの全てが、植毛台１１に植設された複数本のブリッスルの先端を平坦な面に当接させて植毛台１１の後側から３００ｇの荷重を垂直に負荷しつつ刷掃した際に平坦な面に先端が接触するブリッスルである主ブリッスルを構成することになる。
【００２７】
また中央帯状領域１６に植毛されてその先端が当該中央帯状領域１６の上方に位置する第１ブリッスル１４ａ，第２ブリッスル１４ｂ等による中央主ブリッスルの平均植毛高さが、各外側領域１７に植毛されてその先端が当該外側領域１７の上方に位置する第３ブリッスル１４ｃ，第４ブリッスル１４ｄ等による外側主ブリッスルの平均植毛高さよりも例えば１．０ｍｍ高くなると共に、各中央主ブリッスルのかたさ理論値Ｔ _in 及び各外側主ブリッスルのかたさ理論値Ｔ _out から算定した、中央帯状領域の全体のかたさと外側領域の全体のかたさとの比（かたさの内外比）が例えば１．５となる。
【００２８】
そして、本第１実施形態の歯ブラシ１０によれば、植毛高さを変化させて植毛されたブリッスル１４ａ，１４ｂ，１４ｃ，１４ｄによる効率の良い歯間部の刷掃を可能にして、歯垢の除去効果を充分に発揮させることが可能になる。すなわち、本第１実施形態によれば、中央帯状領域１６における中央主ブリッスルと各外側領域１７における外側主ブリッスルとの平均植毛高さの差である凸型の内外段差が例えば１．０ｍｍとなっており、また中央主ブリッスルと外側主ブリッスルによるかたさの内外比が１．５となっているので、外側主ブリッスルよりも毛丈の長い中央主ブリッスルの毛先が刷掃時に歯間部に容易且つスムーズに入り込んで効率良く歯間部の刷掃をおこなうことが可能になる。
【００２９】
また中央主ブリッスルの植毛高さの方が外側主ブリッスルの植毛高さよりも大きくなっているにもかかわらず、中央主ブリッスルの全体のかたさが外側主ブリッスルの全体のかたさよりもかたくなっていることにより、中央主ブリッスルは、コシが弱くなったり撓みすぎることがなく、これによって歯垢の除去効果を充分に発揮することが可能になる。
【００３０】
図２（ａ）及び（ｂ）は、本発明の好ましい第２実施形態に係る歯ブラシ２０を示すものであり、本第２実施形態に係る歯ブラシ２０は、把持部（図示せず）と植毛台２１とこれらを連結する首部２２とからなる歯ブラシ本体の植毛台２１に形成した複数の植毛穴２３ａ，２３ｂ，２３ｃ，２３ｄに、複数本のブリッスル２４ａ，２４ｂ，２４ｃ，２４ｄを束ねてなる毛束（タフト）２５ａ，２５ｂ，２５ｃ，２５ｄを各々植毛（植設）することによって構成されている。
【００３１】
また、本第２実施形態の歯ブラシ２０によれば、歯ブラシ本体は、上記第１実施形態の歯ブラシ１０と同様に、例えばポリプロピレン、ＡＢＳ樹脂等の合成樹脂からなる公知のもので、その植毛台２１の平坦な植毛面には、これの略全域に亘って、歯ブラシ２０の軸方向Ｘと平行な短軸が０．８ｍｍ、これと垂直な長軸が３．０ｍｍのトラック円形状の第１植毛２３ａ穴が５箇所に、歯ブラシ２０の軸方向Ｘと平行な長軸が２．２ｍｍ、これと垂直な短軸が０．８ｍｍのトラック円形状の第２植毛穴２３ｂが１６箇所に、長軸が１．５ｍｍ、短軸が０．８ｍｍのトラック円形状の第３植毛穴２３ｃが５箇所に、同じく長軸が１．５ｍｍ、短軸が０．８ｍｍのトラック円形状の第４植毛穴２３ｄが７箇所に形成されている。
【００３２】
そして、５箇所の第１植毛２３ａ穴には、図２（ａ）において陰線を描いて略示される第１毛束２５ａが、１６箇所の第２植毛２３ｂ穴には、歯ブラシ２０の軸方向Ｘに片寄せた丸を描いて略示される第２毛束２５ｂが、５箇所の第３植毛穴２３ｃには、黒塗りで略示される第３毛束２５ｃが、７箇所の第４植毛穴２３ｄには、白塗りで略示される第４毛束２５ｄが、各々植毛されている。
【００３３】
また、本第２実施形態によれば、植毛台２１の植毛面を歯ブラシ２０の軸方向Ｘと平行な一対の区画線２８によって３ｍｍ幅の中央帯状領域２６とこれの両側の一対の外側領域２７とに区画した際に、中央帯状領域２６には、５箇所の第１毛束２５ａと５箇所の第３毛束２５ｃと１箇所の第４毛束２５ｄとが植毛され、各外側領域２７には、各々８箇所の第２毛束２５ｂと３箇所の第４毛束２５ｄとが植毛されることになる。なお、本第２実施形態によれば、中央帯状領域２６と外側領域２７との間の区画線２８に隣接して配置される第３毛束２５ｃ、第４毛束２５ｄは、その一部のブリッスル２４ｃ，２４ｄが、中央帯状領域２６側又は外側領域２７側にはみ出して植毛されている。
【００３４】
さらに、本第２実施形態によれば、第１毛束２５ａは、太さが９mil（０．２２９ｍｍ）の第１ブリッスル２４ａを３８本束ねて構成されており、各第１ブリッスル２４ａは植毛面から１１．５ｍｍの毛丈で植毛されている。また第２毛束２５ｂは、太さが７mil（０．１７８ｍｍ）の第２ブリッスル２４ｂを４８本束ねて構成されており、各第２ブリッスル２４ｂは植毛面から９．０〜１１．５ｍｍの毛丈で植毛されている。さらに、第３毛束２５ｃは、太さが９mil（０．２２９ｍｍ）の第３ブリッスル２４ｃを１５本束ねて構成されており、各第３ブリッスル２４ｃは植毛面から１１．０〜１２．０ｍｍの毛丈（植毛台２１の先端側の第３毛束２５ｃを構成する第３ブリッスル２４ｃから順番に１１．５ｍｍ、１２．０ｍｍ、１１．５ｍｍ、１１．０ｍｍの毛丈）で植毛されている。さらにまた、第４毛束２５ｄは、太さが８mil（０．２０３ｍｍ）の第４ブリッスル２４ｄを１９本束ねて構成されており、各第４ブリッスル２４ｄは植毛面から１０．５〜１１．５ｍｍの毛丈（植毛台２１の先端側の第４毛束２５ｄを構成する第４ブリッスル２４ｄから順番に１１．５ｍｍ、１１．０ｍｍ、１０．５ｍｍの毛丈）で植毛されている。
【００３５】
したがって、本第２実施形態によれば、５箇所の第３毛束２５ｃと７箇所の第４毛束２５ｄとを合わせた毛束群全体の上端のブラシ面は、植毛台２１の先端側から２列目の２つの第３毛束２５ｃ（毛丈１２．０ｍｍ）が最も高くなった、歯ブラシ２０の側方から視て山型の形状を形成している（図２（ｂ）参照）。
【００３６】
さらにまた、本第２実施形態によれば、上記第２毛束２５ｂは、図２（ａ）のＡ部にその上面図及び側面図を拡大して示すように、最も高い毛丈（１１．５ｍｍ）の８本の第２ブリッスル２４ｂから、最も低い毛丈（９．０ｍｍ）の第２ブリッスル２４ｂに亘って、先端形状が凹状の湾曲形状となるように第２ブリッスル２４ｂの毛丈を順次低くした状態で植毛されるものであり、これによって、植毛台２１の後側から３００ｇの荷重を垂直に負荷しつつ刷掃した際に、毛丈の長い方の２１本の第２ブリッスル２４ｂのみの先端が平坦な面に当接して、当該２１本の第２ブリッスル２４ｂのみが主ブリッスルを構成することになる。
【００３７】
上述のように各毛束２５ａ，２５ｂ，２５ｃ，２５ｄが植毛台２１に植毛されることにより、本第２実施形態の歯ブラシ２０によれば、毛丈の短い方の２７本の第２ブリッスル２４ｂを除いて、各毛束２５ａ，２５ｂ，２５ｃ，２５ｄを構成するブリッスル２４ａ，２４ｂ，２４ｃ，２４ｄが、植毛台１１に植設された複数本のブリッスルの先端を平坦な面に当接させて植毛台１１の後側から３００ｇの荷重を垂直に負荷しつつ刷掃した際に平坦な面に先端が接触するブリッスルである主ブリッスルを構成することになる。
【００３８】
また中央帯状領域２６に植毛される第１ブリッスル２４ａ，第３ブリッスル２４ｃ等による中央主ブリッスルの平均植毛高さが、各外側領域２７に植毛された第２ブリッスル２４ｂ，第４ブリッスル２４ｄ等による外側主ブリッスルの平均植毛高さよりも０．６５ｍｍ高くなると共に、各中央主ブリッスルのかたさ理論値Ｔ _in 及び各外側主ブリッスルのかたさ理論値Ｔ _out から算定した、中央帯状領域の全体のかたさと外側領域の全体のかたさとの比（かたさの内外比）が１．２５となる。
【００３９】
そして、本第２実施形態の歯ブラシ２０によっても、中央帯状領域２６における中央主ブリッスルと各外側領域２７における外側主ブリッスルとの平均植毛高さの差である凸型の内外段差が０．６５ｍｍとなっており、また中央主ブリッスルと外側主ブリッスルによるかたさの内外比が１．２５となっているので、上記第１実施形態の歯ブラシ１０と同様の作用効果を奏することになる。
【００４０】
なお、本発明は上記各実施形態に限定されることなく種々の変更が可能である。例えば、植毛台における植毛穴の形状や配置、各毛束を構成するブリッスルの太さ、本数等は上記各実施形態のものに限定されるものではない。
【００４１】
【実施例】
以下、実施例及び比較例により、本発明の歯ブラシをさらに詳細に説明するが、本発明はこれらに限定されるものではない。
【００４２】
〔実施例１，２〕
上記第１実施形態の歯ブラシ１０と同様の構成を有する歯ブラシを実施例１の歯ブラシとし、上記第２実施形態の歯ブラシ２０と同様の構成を有する歯ブラシを実施例２の歯ブラシとして、後述の歯垢除去率のモデル試験により、歯垢除去率の評価を行った。評価の結果を図６に示す。なお、上述のように、中央帯状領域における中央主ブリッスルと各外側領域における外側主ブリッスルとの平均植毛高さの差である凸型の内外段差は、実施例１では１．０ｍｍ、実施例２では０．６５ｍｍでありとなっており、また中央主ブリッスルと外側主ブリッスルによるかたさの内外比は、実施例１では１．５、実施例２では１．２５である。
【００４３】
〔比較例１〜３〕
算出された内外段差が−０．３ｍｍ、かたさの内外比が１．４である市販品Ａを比較例１の歯ブラシとし、算出された内外段差が０ｍｍ、かたさの内外比が１．０である市販品Ｂを比較例２の歯ブラシとし、算出された内外段差が０．７８ｍｍ、かたさの内外比が０．９８である市販品Ｃを比較例３の歯ブラシとして、後述の歯垢除去率のモデル試験により、歯垢除去率の評価を行った。評価の結果を図６に示す。
【００４４】
〔歯垢除去率のモデル試験〕
図３に示すように、Ｒ４の曲面同士を向き合わせたアルミブロックによる歯間部モデル３０を作成し、この歯間部モデル３０の表面に歯垢モデルとしてビデオテープ磁性層３１を取り付けた。ビデオテープとして、西友プライベートブランドの「Ｓ‘ＲＩＢＢＯＮ」スタンダードタイプ（１２０分、型番３Ｔ−１２０ＳＲ）」を使用した。作成した歯間部モデル３０に対して、ブラッシングマシーンを用いて実施例１，２の歯ブラシ、及び比較例１〜３の歯ブラシの各々による刷掃を行った。刷掃条件は、荷重３００ｇ、速度１２０ｒｐｍ、振幅３０ｍｍ、回数１２０回とし、ハミガキとして研磨促進剤であるアパガードＭプラス（商品名、サンギ社製）を使用した。２πＲ×幅５ｍｍの領域を歯間部の評価領域３２をとし、刷掃後にビデオテープ磁性層３１を展開して、デジタルカメラで撮影すると共に画像解析した。画像解析によって、評価領域３２において磁性層が剥がれて白くなった部分の面積の比率を計算し、歯間部における歯垢除去率とした。評価の結果を図３の各円の中の数値（％）で示す。
【００４５】
図６に示す評価結果によれば、本発明に係る実施例１，２の歯ブラシは、歯間部の歯垢の除去効果について、市販の比較例１〜３の歯ブラシと比較して極めて高い評価が得られることが判明する。
【００４６】
【発明の効果】
本発明の歯ブラシによれば、植毛高さとかたさを変化させて植毛されたブリッスルによる効率の良い歯間部の刷掃を可能にして、歯垢の除去効果を充分に発揮させることができる。
【図面の簡単な説明】
【図１】本発明の第１実施形態に係る歯ブラシの要部を示す略示平面図である。
【図２】本発明の第２実施形態に係る歯ブラシの要部を示す（ａ）は略示平面図及び部分拡大図、（ｂ）は略示側面図である。
【図３】歯垢除去率のモデル試験の説明図である。
【図４】（ａ），（ｂ）は、植毛台の後側から３００ｇの荷重Ｐを垂直に負荷しつつ刷掃した際に、平坦な面に先端が接触する主ブリッスルの説明図である。
【図５】ブリッスルのかたさ理論値Ｔを求める際の梁の撓み式を説明する模式図である。
【図６】歯垢除去率のモデル試験の評価結果を示すチャートである。
【符号の説明】
１０，２０ 歯ブラシ
１１，２１ 植毛台
１２，２２ 首部
１３ 植毛穴
１４ａ，２４ａ 第１ブリッスル
１４ｂ，２４ｂ 第２ブリッスル
１４ｃ，２４ｃ 第３ブリッスル
１４ｄ，２４ｄ 第４ブリッスル
１５ａ，２５ａ 第１毛束
１５ｂ，２５ｂ 第２毛束
１５ｃ，２５ｃ 第３毛束
１５ｄ，２５ｄ 第４毛束
１６，２６ 中央帯状領域
１７，２７ 外側領域
１８，２８ 区画線
２３ａ 第１植毛穴
２３ｂ 第２植毛穴
２３ｃ 第３植毛穴
２３ｄ 第４植毛穴
Ｘ 歯ブラシの軸方向[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toothbrush in which a plurality of bristle bundles formed by bundling a plurality of bristles are implanted on a flocking table.
[0002]
[Prior art and problems to be solved by the invention]
A toothbrush is formed by implanting and fixing a bundle of bristles by, for example, driving a flat wire into a plurality of flock holes provided on a flocking table or fusing them with heat. It is. In addition, the toothbrush is designed to arrange the bristle bundles and bristle so that it can effectively remove the plaque and the like by efficiently performing appropriate brushing according to the parts of the teeth such as the interdental portion, tooth surface portion, and neck portion. Various ideas have been made on the shape of the hair ends.
[0003]
On the other hand, as a toothbrush that can efficiently clean the interdental portion, for example, a bristle bristle tip can be easily inserted into the interdental portion by changing the bristle flocking height. If the height difference of the hair length is too large or the arrangement of the long bristle is not appropriate, the stiffness of the bristle will be too weak due to the relationship with the other bristle with the short hair length. There may be cases where the removal effect cannot be fully exhibited.
[0004]
An object of the present invention is to provide a toothbrush that can efficiently clean the interdental portion by using a bristle planted by changing the height and hardness of the planted hair, and sufficiently exhibiting the effect of removing plaque. Objective.
[0005]
[Means for Solving the Problems]
The present invention is a toothbrush in which a plurality of bristles formed by bundling a plurality of bristles are planted on a flocking table, and the tips of the plurality of bristles planted on the flocking table are brought into contact with a flat surface. For the main bristle, which is a bristle whose tip contacts the flat surface when a load of 300 g is applied vertically from the rear side of the flocking table to make contact, the flocked surface of the flocking table is the axis of the toothbrush. The main bristle having the tip of the bristle positioned on the central band-shaped region is divided into a central band-shaped region having a width of 3 mm parallel to the direction and a pair of outer regions on both sides of the central band-shaped region. When the main bristle to be used is an outer main bristle, the average flocking height of the central main bristle is higher than the average flocking height of the outer main bristle in each outer region, and the following (formula 2) From hardness theoretical value T _out of the central main bristles obtained hardness theory T _in and the outer main bristles, when calculating the overall stiffness of the overall hardness and the outer region of the central strip region, said central strip The above object is achieved by providing a toothbrush having a total area hardness that is greater than the overall hardness of the outer area .
[0006]
[Expression 2]

[0007]
Further, in the toothbrush of the present invention, the average flocking height of the central main bristle is 0.1 to 4.0 mm higher than the average flocking height of the outer main bristle in each of the outer regions , and the hardness of each central main bristle. A ratio (internal / external ratio of hardness ) between the overall hardness of the central strip region and the overall hardness of the outer region, calculated from the theoretical value T _in and the theoretical hardness value T _{out of} each outer main bristle. It is preferably 3.0.
[0008]
Here, in the present application, the “main bristle” is a model shown in FIGS. 4A and 4B, and the tips of a plurality of bristle 51 planted on the flocking table 50 are formed on a flat surface 52. This means a bristle 51a whose tip is in contact with the flat surface 52 when a load P of 300 g is applied from the rear side of the flocking table 50 while making a vertical contact, and the load P of 300 g is applied. Even if the hair flock 50 is moved vertically by the displacement s, its tip does not come into contact with the flat surface 52, except for the bristle 51b where the hair height difference between the longest bristle and 51a is larger than the displacement s. The idea is to think.
[0009]
Further, in the present application, “the bristle stiffness theoretical value T” is the reciprocal of the deflection (v) obtained by the following (Equation 3) with the beam having a circular cross section in the schematic diagram relating to the beam deflection equation shown in FIG. This is a value obtained as (1 / v) and is represented by the following (formula 4).
[0010]
[Equation 3]

[0011]
[Expression 4]

[0012]
Further, in the present application, the central main bristle is a main bristle that is implanted in a central strip region having a width of 3 mm parallel to the axial direction of the toothbrush and whose tip is located above the central strip region, and the hair bundle is in the center. When planted across the lane line between the belt-like region and the outer region, the main bristle divided on the lane line and placed on the central belt-like region side is the central main bristle and placed on the outer region side The formed main bristle is used as the outer main bristle.
[0013]
The width of the central belt-like region is set to 3 mm because of a difference in average flocking height between the central main bristle in the central belt-like region and the outer main bristle in each outer region by a model test of the plaque removal rate described later. As a result of investigating the parameters for the plaque removal rate while changing the width of the central band region under the condition where the convex inner and outer steps and the inner / outer ratio of the central main bristle and the outer main bristle hardness are unified, the central band shape This is because the change in the plaque removal rate is particularly noticeable by setting the width of the region to 3 mm.
[0014]
And, according to the toothbrush of the present invention, the average flocking height of the central main bristle is larger than the average flocking height of the outer main bristle in each outer region, and the theoretical hardness value T _{in of} each central main bristle and the above Since the ratio between the overall hardness of the central strip region and the overall hardness of the outer region calculated from the theoretical hardness value T _{out of} each outer main bristle is greater than 1, the outer side The tip of the central main bristle whose hair length is longer than that of the main bristle can easily and smoothly enter the interdental portion at the time of brushing, so that the interdental portion can be efficiently cleaned.
[0015]
In addition, even though the flocking height of the central main bristle is greater than the flocking height of the outer main bristle, the overall hardness of the central main bristle is harder than the overall hardness of the outer main bristle. As a result, the central main bristle does not weaken or bend too much, thereby making it possible to sufficiently exhibit the plaque removal effect.
[0016]
That is, the inner / outer step, which is the difference in average flocking height between the central main bristle in the central band region and the outer main bristle in the outer region, is made convex, and the inner / outer step is increased, and the inner / outer ratio of hardness is increased. This is considered to be a factor that improves the plaque removal rate at the interdental part. However, if the inner and outer steps are made convex, the hardness ratio becomes 1 or less. On the other hand, according to the present invention, the inner / outer ratio between the central main outer bristle and the outer main main bristle is convex, but the hardness ratio is maintained larger than 1. According to the effect, an excellent effect of removing plaque at the interdental portion can be obtained.
[0017]
According to the present invention, the means for adjusting the inner / outer step between the central main bristle and the outer main bristle to be convex and adjusting the hardness ratio to be greater than 1 is, for example, the hair of each main bristle. A method of adjusting the thickness of the main bristle, a method of adjusting the material of the hair of each main bristle, and the like can be employed.
[0018]
Further, according to the present invention, the convex-inner / outer step which is the difference in average flocking height between the central main bristle and the outer main bristle in each outer region is set to 0.1 to 4.0 mm, and the hardness inner / outer ratio is By setting 1.05 to 4.0, it is possible to improve the plaque removal effect more reliably, and at the same time, the improvement in the interdental feeling during use and the outer area are necessarily soft. It is possible to reduce gingival damage by arranging the hair.
[0019]
And if the range of the convex inner and outer steps is 0.1 to 4.0 mm, the plaque removal effect is improved if there is even a slight difference in the hardness inner / outer ratio in the range of 1.05 to 4.0. It will be. When the convex inner / outer step is 4.0 mm or more, the outer bristles are too short, and the effect of preventing the outer bristle from protruding to the outside is reduced, and the plaque removing effect is lowered .
[0020]
Further, hardness of if the range of the inner and outer ratio from 1.05 to 4.0, range and out stepped convex is 0.1 to 4.0 mm, plaque removal effect becomes hard inside little than the outer Will be improved. If the hardness ratio exceeds 4.0, the difference in hardness between the inner and outer bristle is too large, and the plaque removal effect is reduced. When the hardness ratio exceeds 4.0, for example, the sum of T _in ΣT _in = 0.05 to 0.20 (E is the elastic modulus of nylon bristle) so that the inner bristles have an appropriate hardness. 180kg / mm ² , calculated as k = 1), the outer hair is too soft to prevent the outer bristle from protruding to the outside, and the plaque removal effect is reduced. However, the problem is that the inner hair is too hard and the gums are damaged during brushing.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
The toothbrush 10 according to the first preferred embodiment of the present invention shown in FIG. 1 includes a plurality of flocks 11 formed on a toothbrush main body 11 comprising a gripping part (not shown), a flocking table 11, and a neck 12 connecting them. Each of the hair bundles (tufts) 15a, 15b, 15c, and 15d formed by bundling a plurality of bristles 14a, 14b, 14c, and 14d is implanted in the flock hole 13.
[0022]
According to the toothbrush 10 of the first embodiment, the toothbrush body is a known one made of a synthetic resin such as polypropylene or ABS resin, and the flat flocked surface of the flocking table 11 has a diameter of 1.2 mm. The flock holes 13 having a circular cross section are arranged in a staggered manner and distributed in 40 vertical and horizontal directions over substantially the entire area of the flocked surface, and these flock holes 13 are schematically indicated by white circles in FIG. A single hair bundle 15a is schematically shown by double circles at 12 places, a second hair bundle 15b schematically shown by black circles at 2 places, and a third hair bundle 15c schematically shown by drawing a cross in a circle at 8 places. 15 d of 4th hair | bristle bundles are each implanted by 18 places.
[0023]
Moreover, the bristle 14a, 14b, 14c, 14d which comprises each hair | bristle bundle 15a, 15b, 15c, 15d is a filament material which has a thickness of 6-9 mil which consists of synthetic resins, such as nylon, for example, Each bundle of hairs 15a, 15b, 15c, and 15d is formed by bundling dozens to dozens.
[0024]
According to the first embodiment, the flocked surface of the flocking table 11 is divided into a central strip region 16 having a width of 3 mm and a pair of outer regions 17 on both sides thereof by a pair of partition lines 18 parallel to the axial direction X of the toothbrush 10. When partitioned, twelve first hair bundles 15a and two second hair bundles 15b are planted in the central belt-like region 16, and each of the outer region 17 has four third hair bundles 15c and Nine fourth hair bundles 15d are implanted. Note that, according to the first embodiment, the first hair bundle 15a, the third hair bundle 15c, and the fourth hair bundle 15d arranged adjacent to the partition line 18 between the central belt-like region 16 and the outer region 17. A portion of the bristle 14a, 14c, 14d located at the peripheral edge of the hair protrudes from the central belt-like region 16 side or the outer region 17 side and is implanted.
[0025]
And according to this 1st Embodiment, the 1st hair | bristle bundle 15a is comprised by bundling 16 1st bristle 14a whose thickness is 9 mil (0.229 mm), and each 1st bristle 14a is flocked surface. To 11.5 mm in length. The second bristles 15b are configured by bundling 20 second bristles 14b having a thickness of 8 mil (0.203 mm), and each second bristles 14b is planted with a hair length of 11.5 mm from the flocked surface. ing. Further, the third hair bundle 15c is constituted by bundling 26 third bristles 14c having a thickness of 7 mil (0.178 mm), and each third bristle 14c has a hair height of 10.5 mm from the flocked surface. Has been. Furthermore, the fourth hair bundle 15d is formed by bundling 34 fourth bristle 14d having a thickness of 6 mil (0.152 mm), and each fourth bristle 14d has a hair length of 10.5 mm from the flocked surface. It is flocked.
[0026]
As a result, according to the toothbrush 10 of the first embodiment, all of the bristles 14a, 14b, 14c, and 14d constituting the bristles 15a, 15b, 15c, and 15d are plurally implanted in the flocking table 11. The main bristle, which is a bristle whose tip comes into contact with the flat surface when it is wiped while applying a load of 300 g vertically from the rear side of the flocking table 11 with the tip of the bristle contacting the flat surface, is constituted. It will be.
[0027]
Further, the average flocking height of the central main bristle by the first bristle 14a, the second bristle 14b, etc., which is flocked in the central belt-like region 16 and whose tip is located above the central belt-like region 16, is flocked in each outer region 17. The tip of the lever is 1.0 mm higher than the average flocking height of the outer main bristle by the third bristle 14c, the fourth bristle 14d, etc. located above the outer region 17, and the theoretical hardness T of each central main bristle. was calculated from _in and hardness theoretical value T _out of the outer main bristles, the ratio (out ratio hardness) of the overall stiffness of the overall hardness and the outer region of the central strip region becomes, for example, 1.5.
[0028]
According to the toothbrush 10 of the first embodiment, it is possible to efficiently clean the interproximal portion by the bristle 14a, 14b, 14c, 14d planted by changing the height of flocking, and the plaque The removal effect can be sufficiently exerted. That is, according to the first embodiment, the convex inner / outer step, which is the difference in average flocking height between the central main bristle in the central strip region 16 and the outer main bristle in each outer region 17, is, for example, 1.0 mm. Since the hardness ratio between the central main bristle and the outer main bristle is 1.5, the tip of the central main bristle whose length is longer than that of the outer main bristle can be easily removed between teeth. In addition, the interdental portion can be efficiently cleaned by entering smoothly.
[0029]
The central main bristle is harder than the outer main bristle even though the central main bristle has a higher height than the outer main bristle. As a result, the central main bristle does not weaken or bend too much, thereby making it possible to sufficiently exhibit the plaque removal effect.
[0030]
FIGS. 2A and 2B show a toothbrush 20 according to a second preferred embodiment of the present invention. The toothbrush 20 according to the second embodiment includes a gripping part (not shown) and a flocking table. Bristles 24a, 24b, 24c, 24d are bundled in a plurality of flocking holes 23a, 23b, 23c, 23d formed in a flocking table 21 of a toothbrush main body comprising a neck 21 and a neck portion 22 connecting them. (Tuft) 25a, 25b, 25c, 25d is configured by flocking (planting) each.
[0031]
Further, according to the toothbrush 20 of the second embodiment, the toothbrush body is a known one made of a synthetic resin such as polypropylene or ABS resin, like the toothbrush 10 of the first embodiment. On the flat flocked surface, the first flocked track-shaped flock that has a short axis of 0.8 mm parallel to the axial direction X of the toothbrush 20 and a long axis of 3.0 mm is perpendicular to the axial direction X over substantially the entire area. 23a holes are provided at 5 locations, a long axis parallel to the axial direction X of the toothbrush 20 is 2.2 mm, and a short axis perpendicular to this is a circular track-shaped second flocking hole 23b at 16 locations. Track circular third flocking holes 23c having a long axis of 1.5 mm and a short axis of 0.8 mm. Are formed in seven places.
[0032]
In the five first flocked holes 23a, the first hair bundle 25a, which is schematically shown in a shaded line in FIG. 2 (a), and in the sixteen second flocked holes 23b, the axial direction X of the toothbrush 20 is shown. The second bristle bundle 25b, which is schematically shown by drawing a rounded circle, has five third flocked holes 23c, and the third flocked bundle 25c, schematically shown in black, has seven fourth flocked holes 23d. Each of the fourth hair bundles 25d schematically shown in white is planted.
[0033]
Further, according to the second embodiment, the flocking surface of the flocking table 21 is formed by a pair of partition lines 28 parallel to the axial direction X of the toothbrush 20 and a central strip region 26 having a width of 3 mm and a pair of outer regions 27 on both sides thereof. When divided into five, the central band-like region 26 is planted with five first hair bundles 25a, five third hair bundles 25c, and one fourth hair bundle 25d. In this case, eight second hair bundles 25b and three fourth hair bundles 25d are implanted. Note that, according to the second embodiment, the third hair bundle 25c and the fourth hair bundle 25d arranged adjacent to the partition line 28 between the central belt-like region 26 and the outer region 27 are a part of them. The bristle 24c, 24d protrudes from the central belt-like region 26 side or the outer region 27 side and is planted.
[0034]
Furthermore, according to the second embodiment, the first hair bundle 25a is configured by bundling 38 first bristle 24a having a thickness of 9 mil (0.229 mm), and each first bristle 24a has a flocked surface. To 11.5 mm in length. The second bristle bundle 25b is configured by bundling 48 second bristle 24b having a thickness of 7 mil (0.178 mm), and each second bristle 24b has a bristle of 9.0 to 11.5 mm from the flocked surface. Length and flocked. Further, the third hair bundle 25c is configured by bundling 15 third bristle 24c having a thickness of 9 mil (0.229 mm), and each third bristle 24c is 11.0 to 12.0 mm from the flocked surface. The hair is planted at a hair length (11.5 mm, 12.0 mm, 11.5 mm, 11.0 mm hair length in order from the third bristle 24c constituting the third hair bundle 25c on the tip side of the hair transplant table 21). Further, the fourth hair bundle 25d is configured by bundling 19 fourth bristle 24d having a thickness of 8 mil (0.203 mm), and each fourth bristle 24d is 10.5 to 11.5 mm from the flocked surface. (11.5 mm, 11.0 mm, 10.5 mm hair length in order from the fourth bristle 24 d constituting the fourth hair bundle 25 d on the distal end side of the flocking table 21).
[0035]
Therefore, according to the second embodiment, the brush surface at the upper end of the entire hair bundle group including the five third hair bundles 25c and the seven fourth hair bundles 25d is from the tip side of the flock base 21. The two third bristle bundles 25c (hair length 12.0 mm) in the second row form a mountain shape when viewed from the side of the toothbrush 20 (see FIG. 2B).
[0036]
Furthermore, according to the second embodiment, the second hair bundle 25b has the highest bristle length (11. 2) as shown in an enlarged top view and side view in part A of FIG. 5 mm) to the second bristle 24b having the lowest bristle length (9.0 mm), the bristle length of the second bristle 24b is sequentially changed so that the tip shape becomes a concave curved shape. The hair is planted in a lowered state, so that when the 300 g load is wiped vertically from the rear side of the tuft 21 and only the 21 second bristle 24b having the longer bristle length is used. Only the 21st second bristle 24b constitutes the main bristle.
[0037]
As described above, each of the bristles 25a, 25b, 25c, and 25d is planted on the hair transplant table 21, so that according to the toothbrush 20 of the second embodiment, the 27 second bristle 24b having the shorter bristle length. Except that the bristle 24a, 24b, 24c, 24d constituting each hair bundle 25a, 25b, 25c, 25d makes the tips of a plurality of bristles implanted in the flocking table 11 abut on a flat surface. A main bristle, which is a bristle whose tip comes into contact with a flat surface when it is swept while applying a load of 300 g vertically from the rear side of the flocking table 11, is formed.
[0038]
The average hair height of the central main bristle by the first bristle 24a, the third bristle 24c, etc. planted in the central belt-like region 26 is the outside by the second bristle 24b, the fourth bristle 24d, etc. planted in each outer region 27. 0.65 mm higher than the average flocked height of the main bristle, and the overall hardness and outer region of the central strip region calculated from the theoretical hardness value T _{in of} each central main bristle and the theoretical hardness value T _{out of} each outer main bristle The ratio to the overall hardness (internal / external ratio) is 1.25.
[0039]
And also with the toothbrush 20 of this 2nd Embodiment, the convex inner / outer level | step difference which is the difference of the average flocking height of the center main bristle in the center strip | belt-shaped area | region 26 and the outer main bristle in each outer side area | region 27 is 0.65 mm. In addition, since the hardness ratio between the central main bristle and the outer main bristle is 1.25, the same effect as the toothbrush 10 of the first embodiment can be obtained.
[0040]
The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the shape and arrangement of the flock holes in the flocking table, the thickness and number of bristles constituting each hair bundle are not limited to those in the above embodiments.
[0041]
【Example】
Hereinafter, although the toothbrush of this invention is demonstrated in detail by an Example and a comparative example, this invention is not limited to these.
[0042]
Examples 1 and 2
The toothbrush having the same configuration as the toothbrush 10 of the first embodiment is a toothbrush of Example 1, and the toothbrush having the same configuration as the toothbrush 20 of the second embodiment is a toothbrush of Example 2, which will be described later. The plaque removal rate was evaluated by a model test of the removal rate. The evaluation results are shown in FIG. As described above, the convex inner / outer step, which is the difference in average flocking height between the central main bristle in the central band region and the outer main bristle in each outer region, is 1.0 mm in Example 1, and Example 2 Is 0.65 mm, and the hardness ratio between the central main bristle and the outer main bristle is 1.5 in the first embodiment and 1.25 in the second embodiment.
[0043]
[Comparative Examples 1-3]
A commercially available product A having a calculated inner / outer level difference of −0.3 mm and a hardness / inner / outer ratio of 1.4 is used as the toothbrush of Comparative Example 1, the calculated inner / outer level difference is 0 mm, and the hardness inner / outer ratio is 1.0. The commercially available product B was used as the toothbrush of Comparative Example 2, the calculated internal / external step difference was 0.78 mm, and the commercial product C having a hardness internal / external ratio of 0.98 was used as the toothbrush of Comparative Example 3, and a model of plaque removal rate described later. The plaque removal rate was evaluated by the test. The evaluation results are shown in FIG.
[0044]
[Model test of plaque removal rate]
As shown in FIG. 3, an interdental part model 30 made of aluminum blocks in which curved surfaces of R4 face each other was created, and a video tape magnetic layer 31 was attached to the surface of the interdental part model 30 as a dental plaque model. As a videotape, “S'RIBBON” standard type (120 minutes, model number 3T-120SR) of Seiyu private brand was used. The created interdental part model 30 was brushed with the toothbrushes of Examples 1 and 2 and the toothbrushes of Comparative Examples 1 to 3 using a brushing machine. The cleaning conditions were a load of 300 g, a speed of 120 rpm, an amplitude of 30 mm, and a frequency of 120 times, and Apaguard M Plus (trade name, manufactured by Sangi) as a polishing accelerator was used as a toothpaste. The evaluation area 32 of the interdental area was defined as an area of 2πR × width 5 mm, and after the brushing, the video tape magnetic layer 31 was developed, photographed with a digital camera, and image analysis was performed. By image analysis, the ratio of the area of the evaluation region 32 where the magnetic layer was peeled off and whitened was calculated, and the plaque removal rate at the interdental part was calculated. The result of the evaluation is indicated by a numerical value (%) in each circle in FIG.
[0045]
According to the evaluation results shown in FIG. 6, the toothbrushes of Examples 1 and 2 according to the present invention have extremely high evaluations regarding the effect of removing plaque at the interdental part as compared with the commercially available toothbrushes of Comparative Examples 1 to 3. It turns out that is obtained.
[0046]
【The invention's effect】
According to the toothbrush of the present invention, it is possible to efficiently clean the interdental portion by the bristle planted by changing the height and hardness of the planted hair, and sufficiently exhibit the plaque removal effect.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing a main part of a toothbrush according to a first embodiment of the present invention.
FIGS. 2A and 2B are a schematic plan view and a partially enlarged view showing a main part of a toothbrush according to a second embodiment of the present invention, and FIG.
FIG. 3 is an explanatory diagram of a model test of plaque removal rate.
FIGS. 4A and 4B are explanatory views of a main bristle whose tip comes into contact with a flat surface when it is swept while applying a load P of 300 g vertically from the rear side of the flocking table. .
FIG. 5 is a schematic diagram for explaining a bending equation of a beam at the time of obtaining a bristle hardness theoretical value T;
FIG. 6 is a chart showing the evaluation results of a model test of plaque removal rate.
[Explanation of symbols]
10, 20 Toothbrushes 11, 21 Flocking table 12, 22 Neck portion 13 Flocking holes 14a, 24a First bristles 14b, 24b Second bristles 14c, 24c Third bristles 14d, 24d Fourth bristles 15a, 25a First bristles 15b, 25b Second hair bundles 15c, 25c Third hair bundles 15d, 25d Fourth hair bundles 16, 26 Central belt-like regions 17, 27 Outer regions 18, 28 Partition line 23a First flocking hole 23b Second flocking hole 23c Third flocking hole 23d 4th flock hole X Toothbrush axial direction

Claims (2)

A toothbrush in which a plurality of bristle bundling bristles are planted on a flocking table,
When the front ends of the plurality of bristles planted on the flocking table are brought into contact with a flat surface and a 300 g load is applied vertically from the rear side of the flocking table, the flat surface is cleaned. For the main bristle that is the bristle with which the tip contacts, the flocked surface of the flocking table is divided into a 3 mm wide central strip region parallel to the axial direction of the toothbrush and a pair of outer regions on both sides thereof, and the bristle tip is When the main bristle located on the central strip region is a central main bristle and the main bristle located on the outer region is an outer main bristle,
The average flocking height of the central main bristle is higher than the average flocking height of the outer main bristle in each outer region,
Further, from the theoretical hardness value T _{in of} each central main bristle and the theoretical hardness value T _{out of} each outer main bristle determined by the following (Equation 1), the overall hardness of the central strip region and the overall hardness of the outer region are calculated. A toothbrush in which, when calculated, the overall hardness of the central strip region is greater than the overall hardness of the outer region .

Mean flocking height of the central main bristles, 0.1 to 4.0 mm higher than the average flocking height of outer main bristles in each said outer region of the hardness theoretical value T _in and the respective outside of each central main bristles The ratio (internal / external ratio of hardness ) between the overall hardness of the central strip region and the overall hardness of the outer region calculated from the theoretical hardness value T _{out of the} main bristle is 1.05 to 3.0. The toothbrush described.

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