FIELD OF THE INVENTION

The present disclosure is concerned with a head for an oral care implement, the head comprising at least one tooth cleaning element of a first type and least one tooth cleaning element of a second type. The at least one tooth cleaning element of the first type is a tuft of a first type comprising a plurality of filaments with a substantially cross-shaped cross-sectional area. The present disclosure is further concerned with an oral care implement comprising such head.

BACKGROUND OF THE INVENTION

Tufts composed of a plurality of filaments for oral care implements, like manual and powered toothbrushes, are well known in the art. Generally, the tufts are attached to a bristle carrier of a head intended for insertion into a user's oral cavity. A grip handle is usually attached to the head, which handle is held by the user during brushing. The head is either permanently connected or repeatedly attachable to and detachable from the handle.

In order to clean teeth effectively, appropriate contact pressure has to be provided between the free ends of the filaments and the teeth. Generally, the contact pressure depends on the bending stiffness and the displacement of the filaments, while the bending stiffness of a single filament depends on its length and cross sectional area. Usually, filaments with greater length show lower bending stiffness as compared to shorter filaments. However, relatively thin filaments tend to flex away easily and the relatively low bending stiffness results in reduced plaque removal efficiency on teeth surfaces, as well as in less interdental penetrations properties and cleaning performance. In order to compensate said reduction in bending stiffness of longer filaments, the size of the cross sectional area of a filament could be increased. However, relatively thick filaments may create an unpleasant brushing sensation and tend to injure the gums in the oral cavity. In addition, thicker filaments may show reduced bend recovery and usage of said filaments may generate a worn-out impression of the tuft pattern after a relatively short time of use.

Further, filaments having a profile along their length extension resulting in a non-circular cross sectional area, e.g. a polygonal- or a cross-shaped cross sectional area, are also known in the art. Such filaments should improve cleaning properties of oral care implements during normal use. In particular, the profiled edges should provide a stronger scraping action during a brushing process to improve removal of plaque and other residuals on the teeth surfaces.

While toothbrushes comprising conventional type of tufts clean the outer buccal face of teeth adequately, they are generally not as well suited to provide adequate removal of plaque and debris from the interproximal areas and other hard to reach regions of the mouth since penetration into interdental spaces is still relatively difficult. In particular, they are not well suited to sufficiently clean the gingival margin, interdental spaces and other hard to reach areas where typically plaque starts to grow. Thus, in order to achieve and preserve good oral health, and to prevent gingivitis, it is important to clean along the gum line and, in particular, the gap between teeth and periodontium, the so called gingival groove. It is known that a lack of good removal of plaque in the gingival groove can cause gingivitis, i.e. inflammation of the gum tissue. Additionally, standard tufts do not provide sufficient capillary effects to remove plaque and debris from the teeth and gum surfaces during brushing. However, in order to achieve good cleaning results, the plaque must be reached by the tufts/filaments, then the plaque must be disrupted and, finally, taken away. Further, the tufts shall provide good sensory feeling on the gums during brushing.

Additionally, the mechanical stress occurring within a cross-shaped filament during a brushing process leads to higher stress in the tips of the cross-shaped filaments as compared to circular-shaped filaments. This means, in tufts having the same overall stiffness, cross-shaped filaments have to bear higher maximum stress values as compared to circular-shaped filaments. This increased stress in the individual cross-shaped filaments can lead to an increased wear behavior during usage. This wear is characterized by an increased splay of the tuft which leads to less consumer acceptance.

It is an object of the present disclosure to provide a head for an oral care implement which overcomes at least one of the above-mentioned drawbacks. It is also an object of the present disclosure to provide an oral care implement comprising such head.

SUMMARY OF THE INVENTION

In accordance with one aspect, a head for an oral care implement is provided, the head comprising at least one tooth cleaning element of a first type and at least one tooth cleaning element of a second type, the at least one tooth cleaning element of the first type having a length extension along a longitudinal axis being about 1 mm to about 2 mm shorter than the length extension of the at least one tooth cleaning element of the second type along its longitudinal axis, the at least one tooth cleaning element of the first type being a tuft of a first type comprising a plurality of filaments, each filament having a longitudinal axis and a substantially cross-shaped cross-sectional area extending in a plane substantially perpendicular to the longitudinal axis, the cross-shaped cross-sectional area having four projections and four channels, the projections and channels being arranged in an alternating manner, wherein the at least one tuft of the first type has a packing factor within a range from about 40% to about 55%, preferably from about 45% to about 50%.

In accordance with one aspect an oral care implement is provided that comprises such head.

