Dental flossing device and method therefor

• US 5,944,033 A
• Filed: 04/27/1998
• Issued: 08/31/1999
• Est. Priority Date: 01/07/1993
• Status: Expired due to Fees

• Current Assignee: Dane Robinson
• Original Assignee: Dane Robinson
• Inventors: Robinson, Dane Q.
• Primary Examiner(s): Manahan, Todd E.
• Application Number:
  US09/067,335
• Time in Patent Office: 491 Days
• Field of Search: 132/321, 132/322, 132/323, 132/324, 433/82, 433/118, 433/142, 433/141, 433/143, 601/139, 601/141, 601/142, 601/162
• US Class Current: 132/322
• CPC Class Codes: A61C 15/047 power-driven
• CPC Class Codes: A61C 17/34 driven by electric motor
• CPC Class Codes: A61C 17/3463 Translation along the axis perpendicular to the plane defined by the bristle holder
• CPC Class Codes: A61C 2204/002 using batteries

Abstract

An electromechanical dental flossing device is disclosed for flossing the area between a portion of the tooth and the gum tissue. The device comprises an elongated member coupled to a motor source to effect oscillation of the elongated member. The elongated member includes an intermediate portion and a tip which are capable of being received between the tooth and the gum tissue.

Claims

1. Apparatus for cleaning the surfaces of teeth underlying the inter-dental papilla portion of the gums in a human mouth by effecting a flossing action, comprising:

at least one flexible, resilient, non-abrasive elongated member;

said at least one elongated member including a base portion, an elongated intermediate portion of predetermined cross-sectional configuration, and a tip;

said intermediate portion and said tip being oriented and sized to be received in lengthwise arrangement between adjacent teeth without traversing any contact areas between the teeth from at least the front of the mouth and being sufficiently flexible and resilient to effect the flossing action therebetween by imparting a flossing motion to said intermediate portion; and

at least said intermediate portion being sized to be received in the sulcus between a tooth and the adjacent inter-dental papilla portion of the gum for effecting the flossing action therebetween;

a handle; and

a coupling releasably connecting the base portion of said at least one elongated member to said handle, said coupling holding said at least one elongated member for endwise insertion thereof between the adjacent teeth with said tip being inserted first followed by said intermediate portion, said intermediate portion being held in position extending lengthwise between the adjacent teeth with a lengthwise extending sidewall thereof when said intermediate portion is received in the sulcus engaging the tooth to apply the flossing action thereto as said intermediate portion moves with said flossing motion, said base portion remaining exterior of the adjacent teeth, said coupling applying a moving force to said at least one elongated member with at least one of a translational and a rotational component to impart said flossing motion to said intermediate portion.

2. The apparatus of claim 1, wherein both said intermediate portion and said tip are sized to be received in the sulcus between a tooth and the adjacent inter-dental papilla portion of the gum.

3. The apparatus of claim 1, wherein said intermediate portion has a generally circular cross-section and a diameter no greater than approximately 0.025 inch.

4. The apparatus of claim 1, wherein said at least one elongated member consists of a single filament.

5. The apparatus of claim 1, wherein said coupling comprises an aperture configured to receive said elongated member base portion.

6. The apparatus of claim 1, wherein said coupling is detachably connected to said at least one elongated member.

7. The apparatus of claim 1 wherein said at least one elongated member has a sufficiently large length and a sufficiently small width to position said intermediate portion in lengthwise arrangement between the adjacent teeth with said base portion on one of the front and back sides of the adjacent teeth and said tip on an opposite one of the front and back sides of the adjacent teeth and extending beyond the adjacent teeth.

8. Apparatus for cleaning the surfaces of teeth underlying the inter-dental papilla portion of the gums in a human mouth by effecting a flossing action, comprising:

a flossing device having at least one flexible, resilient, non-abrasive flossing filament;

said at least one flossing filament including a base portion, a free-end portion, and an elongated intermediate portion located between said base portion and said free-end portion;

said intermediate portion and said free-end portion being sized to be received endwise between adjacent teeth and extend lengthwise therebetween without traversing any contact areas between the teeth from at least the front of the mouth, at least said intermediate portion having sufficient flexibility, resiliency and length to effect the flossing action therebetween by imparting a flossing motion to said intermediate portion, said intermediate portion extending along a longitudinal line when not moving;

at least said intermediate portion being sized to be received in the sulcus between a tooth and the adjacent inter-dental papilla portion of the gum for effecting the flossing action therein;

a motive source; and

a coupling connecting said base portion of said at least one flossing filament to said motive source and moving said at least one flossing filament with a component of motion out of alignment with said longitudinal line to impart said flossing motion to said intermediate portion in response to operation of said motive source, said coupling holding said at least one flossing filament for endwise insertion thereof between the adjacent teeth with said free-end portion being inserted first followed by said intermediate portion, when inserted and said intermediate portion is received in the sulcus, said coupling holding said intermediate portion in position extending lengthwise between the adjacent teeth with a lengthwise extending sidewall thereof engaging the tooth to apply the flossing action thereto as said intermediate portion moves with the flossing motion.

9. The apparatus of claim 8 wherein said at least one flossing filament consists of a single flossing filament.

10. The apparatus of claim 8 wherein said coupling imparts said flossing motion to said intermediate portion with a rotational component.

11. The apparatus of claim 8 wherein said motive source is rotatably connected by said coupling to said base portion to provide rotational drive to said at least one flossing filament to produce said flossing motion.

12. The apparatus of claim 8 wherein said motive source produces a rotational output drive and is connected by said coupling to said base portion to supply said rotational output drive to said at least one flossing filament to move said at least one flossing filament along a generally conical path of travel to produce said flossing motion of said intermediate portion.

13. The apparatus of claim 8 wherein said motive source produces a rotational output drive and said coupling translates said rotational drive into an oscillatory drive and supplies said oscillatory drive to said base portion to produce said flossing motion of said intermediate portion.

14. The apparatus of claim 8 wherein said motive source produces an output drive and said coupling translates said output drive into a rotational drive and supplies said rotational drive to said base portion to produce said flossing motion of said intermediate portion.

15. The apparatus of claim 8 wherein said motive source produces an output drive and said coupling translates said output drive into an oscillatory drive and supplies said oscillatory drive to said base portion to move said at least one flossing filament with said component of motion out of alignment with said longitudinal line and produce said flossing motion of said intermediate portion.

16. The apparatus of claim 8 wherein said at least one flossing filament has a sufficiently large length and a sufficiently small width to position said intermediate portion in lengthwise orientation between the adjacent teeth with said base portion on one of the front and back sides of the adjacent teeth and said free-end portion on an opposite one of the front and back sides of the adjacent teeth and extending beyond the adjacent teeth.

17. Apparatus for cleaning the surfaces of teeth underlying the inter-dental papilla portion of the gums in a human mouth by effecting a flossing action, comprising:

a flossing device having at least one flexible, resilient flossing filament;

said at least one flossing filament including a first portion, a second, free-end portion, and a non-abrasive elongated intermediate portion located between said first portion and said free-end portion;

said intermediate portion and said free-end portion being sized to be received endwise between adjacent teeth and extend lengthwise therebetween without traversing any contact areas between the teeth from at least the front of the mouth, at least said intermediate portion having sufficient flexibility, resiliency and length to effect the flossing action therebetween by imparting a flossing motion to said intermediate portion;

at least said intermediate portion being sized to be received in the sulcus between a tooth and the adjacent inter-dental papilla portion of the gum for effecting the flossing action therein;

a motive source; and

a coupling connecting said at least one flossing filament to said motive source and applying a moving force to said at least one flossing filament with at least one of a translational and a rotational component to impart said flossing motion to said intermediate portion, said coupling holding said at least one flossing filament for endwise insertion thereof between the adjacent teeth with said free-end portion being inserted first followed by said intermediate portion, when inserted said coupling holding said intermediate portion in position extending lengthwise between the adjacent teeth.

18. The apparatus of claim 17 wherein said at least one flossing filament consists of a single flexible, resilient flossing filament.

19. The apparatus of claim 17 wherein said motive source is rotatably connected by said coupling to said at least one flossing filament to provide rotational drive to said at least one flossing filament to produce said flossing motion of said intermediate portion.

20. The apparatus of claim 17 wherein said motive source produces a rotational output drive and is connected by said coupling to said at least one flossing filament to supply said rotational output drive to said at least one flossing filament to move said at least one flossing filament along a generally conical path of travel to produce said flossing motion of said intermediate portion.

21. The apparatus of claim 17 wherein said motive source produces a rotational output drive and said coupling translates said rotational drive into an oscillatory drive and supplies said oscillatory drive to said at least one flossing filament to produce said flossing motion of said intermediate portion.

22. The apparatus of claim 17 wherein said motive source produces an output drive and said coupling translates said output drive into a rotational drive and supplies said rotational drive to said at least one flossing filament to produce said flossing motion of said intermediate portion.

23. The apparatus of claim 17 wherein said intermediate portion extends along a longitudinal line when not moving, said motive source produces an output drive, and said coupling translates said output drive into an oscillatory drive and supplies said oscillatory drive to said at least one flossing filament to move said at least one flossing filament with a component of motion out of alignment with said longitudinal line and produce said flossing motion of said intermediate portion.

24. The apparatus of claim 17 wherein said coupling applies said moving force to said at least one flossing filament with a rotational component to rotate said at least one flossing filament, and said intermediate portion has sufficient flexibility to bend outward while rotating in response to the centrifugal force thereon resulting from rotation of said at least one flossing filament by said motive source.

25. The apparatus of claim 17 wherein said at least one flossing filament has sufficient flexibility to bend under the force applied thereto resulting from movement of said at least one flossing filament by said motive source to produce said flossing motion of said intermediate portion.

26. The apparatus of claim 17 wherein said motive source provides driving movement of said at least one flossing filament to produce said flossing movement of said intermediate portion, and the apparatus further includes a filament support positioned between said free-end portion and said first portion of said at least one flossing filament to support said at least one flossing filament at a location therealong, said free-end portion and an elongated portion of said intermediate portion extending beyond said filament support for engagement with the tooth when said motive source is operating.

27. The apparatus of claim 17 wherein said motive source includes a drive shaft and said coupling connects said first portion of said at least one flossing filament to said drive shaft in generally coaxial alignment therewith.

28. The apparatus of claim 17 wherein said motive source provides a unidirectional rotational drive to said at least one flossing filament to produce said flossing motion in response to operation of said motive source.

29. The apparatus of claim 17 wherein said motive source provides a non-reciprocating, unidirectional rotational drive to said at least one flossing filament to produce said flossing motion in response to operation of said motive source.

30. The apparatus of claim 17 wherein said at least one flossing filament is elongated with a longitudinal axis and the apparatus further includes a filament support positioned between said free-end portion and said first portion of said at least one flossing filament to support said at least one flossing filament for rotation about said longitudinal axis in response to said rotational drive provided thereto by said motive source, with said free-end portion and an elongated portion of said intermediate portion extending beyond said filament support for engagement with the tooth when said motive source is operating.

31. The apparatus of claim 30 wherein said intermediate portion extending beyond said filament support has sufficient flexibility to bend outward under the centrifugal force thereon resulting from rotation of said at least one flossing filament by said motive source.

32. The apparatus of claim 30 wherein said motive source is rotatably connected by said coupling to said first portion, and said intermediate portion extending beyond said filament support has sufficient flexibility to bend outward while rotating in response to the centrifugal force thereon resulting from rotation of said first portion by said motive source.

33. The apparatus of claim 30, further including a housing containing said motive source and said coupling, and wherein said filament support is removably attached to said housing.

34. The apparatus of claim 17 wherein said motive source is a motor.

35. The apparatus of claim 34, wherein said motor produces a rotational output drive and said coupling converts said rotational output drive into said moving force applied to said at least one flossing filament.

36. The apparatus of claim 34, wherein said motor produces a rotational output drive and said coupling converts said rotational output drive into said moving force with a force component out of longitudinal alignment with said at least one flossing filament to produce a component of motion out of longitudinal alignment with said at least one flossing filament.

37. The apparatus of claim 17 wherein said coupling applies said moving force to said at least one flossing filament with a force component out of longitudinal alignment with said at least one flossing filament to effect said flossing motion of said intermediate portion.

38. The apparatus of claim 17 wherein said flossing device has a sufficiently large length and a sufficiently small thickness to position the entirety of said intermediate portion in lengthwise orientation between the adjacent teeth with said first portion located on one of the front and back sides of the adjacent teeth and said free-end portion located on an opposite one of the front and back sides of the adjacent teeth and extending beyond the adjacent teeth.

39. Apparatus for cleaning the surfaces of teeth underlying the inter-dental papilla portion of the gums in a human mouth by effecting a flossing action, comprising:

a flossing device having at least one flexible, resilient flossing filament having sufficient stiffness to be self-supporting;

said at least one flossing filament including a first portion, a second, free-end portion, and a non-abrasive elongated intermediate portion located between said first portion and said free-end portion;

said intermediate portion and said free-end portion being sized to be received endwise between adjacent teeth and extend lengthwise therebetween without traversing any contact areas between the teeth from at least the front of the mouth, at least said intermediate portion being composed of a material having sufficient flexibility and resiliency to effect the flossing action therebetween without damage to the teeth by imparting a flossing motion to said intermediate portion, said intermediate portion extending along a longitudinal extension line when not moving;

at least said intermediate portion being sized to be received in the sulcus between a tooth and the adjacent inter-dental papilla portion of the gum for effecting the flossing action therein;

a motive source; and

a coupling connecting said at least one flossing filament to said motive source and moving said intermediate portion among a plurality of positions substantially out of alignment with said longitudinal line to impart said flossing motion to said intermediate portion, said coupling holding said at least one flossing filament for endwise insertion thereof between the adjacent teeth with said free-end portion being inserted first followed by said intermediate portion, when inserted said coupling holding said intermediate portion in position extending lengthwise between the adjacent teeth.

40. The apparatus of claim 39 wherein said at least one flossing filament consists of a single flossing filament.

41. The apparatus of claim 39 wherein said flossing device has a sufficiently large length and a sufficiently small thickness to position the entirety of said intermediate portion in lengthwise orientation between the adjacent teeth with said first portion located on one of the front and back sides of the adjacent teeth and said free-end portion located on an opposite one of the front and back sides of the adjacent teeth and extending beyond the adjacent teeth.

42. Apparatus for cleaning the surfaces of teeth underlying the inter-dental papilla portion of the gums in a human mouth by effecting a flossing action, comprising:

an elongated flossing head comprised of at least one flexible, resilient flossing filament;

said flossing head including a base portion, a free-end portion, and a non-abrasive elongated intermediate portion located between said base portion and said free-end portion;

said intermediate portion and said free-end portion being capable of being received endwise between adjacent teeth and extend lengthwise therebetween without traversing any contact areas between the teeth from at least the front of the mouth, at least said intermediate portion having sufficient flexibility and resiliency to be capable of effecting the flossing action therebetween by imparting a flossing motion to said intermediate portion, said intermediate portion extending along a longitudinal line when not moving;

at least said intermediate portion being capable of being received in the sulcus between a tooth and the adjacent inter-dental papilla portion of the gum for effecting the flossing action therein;

a motive source to provide drive to said flossing head; and

a coupling connecting said flossing head to said motive source and moving said flossing head with a component of motion out of alignment with said longitudinal line to impart said flossing motion to said intermediate portion.

43. The apparatus of claim 42 wherein said flossing head has a sufficiently large length and a sufficiently small thickness to position the entirety of said intermediate portion in lengthwise orientation between the adjacent teeth with said base portion located on one of the front and back sides of the adjacent teeth and said free-end portion located on an opposite one of the front and back sides of the adjacent teeth and extending beyond the adjacent teeth.

44. The apparatus of claim 42 wherein said at least one flossing filament consists of a single flexible, resilient flossing filament.

45. The apparatus of claim 42 wherein said coupling holds said flossing head for endwise insertion thereof between the adjacent teeth with said free-end portion being inserted first followed by said intermediate portion, when inserted said coupling holding said intermediate portion in position extending lengthwise between the adjacent teeth.

46. Apparatus for cleaning the surfaces of teeth underlying the inter-dental papilla portion of the gums in a human mouth by effecting a flossing action, comprising:

at least one flexible, resilient flossing filament;

said at least one flossing filament including a first portion, a second, free-end portion, and a non-abrasive, elongated intermediate portion located between said first portion and said free-end portion;

said intermediate portion and said free-end portion being sized to be received endwise between adjacent teeth and extend lengthwise therebetween without traversing any contact areas between the teeth from at least the front of the mouth, at least said intermediate portion having sufficient flexibility, resiliency and length to be capable of effecting the flossing action therebetween by imparting a flossing motion to said intermediate portion;

at least said intermediate portion being sized to be received in the sulcus between a tooth and the adjacent inter-dental papilla portion of the gum for effecting the flossing action therein;

a motive source, said motive source producing an output drive; and

a coupling connecting said at least one flossing filament to said motive source and imparting said flossing motion to said intermediate portion in response to operation of said motive source, said coupling providing an oscillatory drive to said at least one flossing filament to move said at least one flossing filament along a generally translatory path of travel to produce said flossing motion of said intermediate portion, said coupling holding said at least one flossing filament in position for endwise insertion thereof between the adjacent teeth with said free-end portion being inserted first followed by said intermediate portion, when inserted said coupling holding said intermediate portion in position extending lengthwise between the adjacent teeth.

47. The apparatus of claim 46 wherein said coupling translates said output drive into said oscillating drive.

48. The apparatus of claim 47 wherein said output drive of said motive source is a rotational drive, and said coupling translates said rotational drive into said oscillatory drive.

49. The apparatus of claim 47 wherein said motive source is a motor producing a rotational drive as said output drive and said coupling translates said rotational drive into said oscillatory drive.

50. The apparatus of claim 46, wherein said intermediate portion has sufficient length to extend from the front of the mouth between and rearward beyond adjacent teeth.

51. The apparatus of claim 46, wherein said at least one flossing filament consists of a single filament.

52. The apparatus of claim 46, wherein said coupling applies a force component out of alignment with said at least one flossing filament which includes at least one of a translational and a rotational component.

53. A method for cleaning the surfaces of teeth underlying the inter-dental papilla portion of the gums in a human mouth by effecting a flossing action, comprising:

providing a motive source;

providing a flossing device having at least one flexible, resilient flossing filament having a first portion, a second free-end portion, and a non-abrasive intermediate portion located between said first portion and said free-end portion, at least said intermediate portion having sufficient flexibility and resiliency to effect the flossing action between adjacent teeth by producing a flossing motion when driven by said motive source;

inserting endwise said at least one flossing filament between the adjacent teeth with said free-end portion being inserted first from the front of the mouth followed by said intermediate portion without traversing any contact areas between the teeth;

positioning said intermediate portion to extend lengthwise between the adjacent teeth with at least said intermediate portion in the sulcus between a tooth and the adjacent inter-dental papilla portion of the gum for effecting the flossing action therein; and

driving said at least one flossing filament with said motive source to produce said flossing motion of said intermediate portion.

54. The method of claim 53 wherein the step of driving said at least one flossing filament includes moving said at least one flossing filament with a rotational component to impart said flossing motion to said intermediate portion.

55. The method of claim 53 wherein the step of driving said at least one flossing filament includes applying a moving force to said at least one flossing filament with at least one of a translational and a rotational component to effect said flossing motion of said intermediate portion.

56. The method of claim 53, further including extending said free-end portion inward beyond the adjacent teeth.

57. The method of claim 53 wherein a lengthwise extending sidewall of said intermediate portion is positioned in the sulcus and engaged with the tooth to apply the flossing action thereto as said intermediate portion moves with the flossing motion.

58. The method of claim 53 wherein the step of providing said flossing device provides said flossing device consisting of a single flossing filament.

59. The method of claim 53 wherein the entirety of said flossing device is positioned between the adjacent teeth extending lengthwise therebetween.

60. Apparatus for cleaning the surfaces of teeth underlying the inter-dental papilla portion of the gums in a human mouth by effecting a flossing action, comprising:

at least one flexible, resilient, non-abrasive elongated member;

said at least one elongated member including a base portion, an elongated intermediate portion of predetermined cross-sectional configuration, and a tip;

said intermediate portion and said tip being oriented and sized to be received in lengthwise arrangement between adjacent teeth without traversing any contact areas between the teeth from at least the front of the mouth and being sufficiently flexible and resilient to effect the flossing action therebetween by imparting a flossing motion to said intermediate portion; and

at least said intermediate portion being sized to be received in the sulcus between a tooth and the adjacent inter-dental papilla portion of the gum for effecting the flossing action therebetween; and

a handle connected to the base portion of said at least one elongated member, said handle holding said at least one elongated member for unobstructed endwise insertion thereof between the adjacent teeth with said tip being inserted first followed by said intermediate portion, said intermediate portion being held in position extending lengthwise between the adjacent teeth with a lengthwise extending sidewall thereof when said intermediate portion is received in the sulcus engaging the tooth to apply the flossing action thereto as said intermediate portion moves with said flossing motion, said base portion remaining exterior of the adjacent teeth, said handle applying a moving force to said at least one elongated member with at least one of a translational and a rotational component to impart said flossing motion to said intermediate portion.

61. The apparatus of claim 60 wherein both said intermediate portion and said tip are sized to be received in the sulcus between a tooth and the adjacent inter-dental papilla portion of the gum.

62. The apparatus of claim 60 wherein said elongated member consists of a single filament.

63. The apparatus of claim 60, further including a coupling connecting said base portion to said handle.

64. The apparatus of claim 60 wherein said at least one elongated member has a sufficiently large length and a sufficiently small width to position said intermediate portion in lengthwise arrangement between the adjacent teeth with said base portion on one of the front and back sides of the adjacent teeth and said tip on an opposite one of the front and back sides of the adjacent teeth and extending beyond the adjacent teeth.

65. Apparatus for cleaning the surfaces of teeth underlying the inter-dental papilla portion of the gums in a human mouth by effecting a flossing action, comprising:

a flossing device having at least one flexible, resilient flossing filament;

said at least one flossing filament including a first portion, a second, free-end portion, and a non-abrasive elongated intermediate portion located between said first portion and said free-end portion;

said intermediate portion and said free-end portion being sized to be received endwise between adjacent teeth and extend lengthwise therebetween without traversing any contact areas between the teeth from at least the front of the mouth, at least said intermediate portion having sufficient flexibility, resiliency and length to effect the flossing action therebetween by imparting a flossing motion to said intermediate portion;

at least said intermediate portion being sized to be received in the sulcus between a tooth and the adjacent inter-dental papilla portion of the gum for effecting the flossing action there; and

a motive source applying a moving force to said at least one flossing filament with at least one of a translational and a rotational component to impart said flossing motion to said intermediate portion, said at least one flossing filament being positioned for endwise insertion thereof between the adjacent teeth with said free-end portion being inserted first followed by said intermediate portion, when inserted and said intermediate portion is received in the sulcus, said intermediate portion being in position extending lengthwise between the adjacent teeth with a lengthwise extending sidewall portion thereof engaging the tooth to apply the flossing action thereto as said intermediate portion moves with said flossing motion.

66. The apparatus of claim 65 wherein said at least one flossing filament consists of a single flexible, resilient flossing filament.

67. The apparatus of claim 65 wherein said at least one flossing filament has sufficient flexibility to bend under the force applied thereto resulting from movement of said at least one flossing filament by said motive source to produce said flossing motion of said intermediate portion.

68. The apparatus of claim 65 wherein said motive source applies said moving force to said at least one flossing filament with a force component out of longitudinal alignment with said at least one flossing filament to effect said flossing motion of said intermediate portion.

69. The apparatus of claim 65 wherein said motive source produces an oscillatory drive and supplies said oscillatory drive to said at least one flossing filament to impart said flossing motion to said intermediate portion.

70. The apparatus of claim 65 wherein said motive source produces an oscillatory drive and supplies said oscillatory drive to said at least one flossing filament to move said at least one flossing filament with a component of motion out of alignment with a longitudinal line along which said intermediate portion extends when not moving and thereby produce said flossing motion of said intermediate portion.

71. The apparatus of claim 65 wherein said intermediate portion extends along a longitudinal line when not moving, and said motive source moves said intermediate portion among a plurality of positions substantially out of alignment with said longitudinal line to impart said flossing motion to said intermediate portion.

72. The apparatus of claim 65 wherein said motive source moves said at least one flossing filament along a generally translating path of travel to produce said flossing motion of said intermediate portion.

73. The apparatus of claim 65 wherein said flossing device has a sufficiently large length and a sufficiently small thickness to position the entirety of said intermediate portion in lengthwise orientation between the adjacent teeth with said first portion located on one of the front and back sides of the adjacent teeth and said free-end portion located on an opposite one of the front and back sides of the adjacent teeth and extending beyond the adjacent teeth.

74. The apparatus of claim 65 wherein said motive source is a motor.

75. The apparatus of claim 65 wherein said first portion of said at least one flossing filament is a base portion.