nylon bones

RE: nylon bones

Anthony Dennison — Fri, 07 Dec 2018 16:53:30 GMT

[quote user="Iain Richards"]Should be banned (unless from UK). Small but real risk of CWD introduction (BSE for deer).[/quote]

Oh bloody hell. My Dad has already complained once to Pets at Home leading to them recalling one of their products. If he gets hold of this he'll have a field day.

RE: nylon bones

Iain Richards — Tue, 04 Dec 2018 20:35:24 GMT

[quote user="Robert FalconerTaylor"]Very interesting thread, what are your thoughts on deer antler chews Evelyn? [/quote]

Should be banned (unless from UK). Small but real risk of CWD introduction (BSE for deer).

RE: nylon bones

Evelyn Barbour-Hill — Tue, 04 Dec 2018 14:04:24 GMT

[quote user="Robert FalconerTaylor"]Very interesting thread, what are your thoughts on deer antler chews Evelyn? Anecdotally, from what I've seen there does seem to be quite a lot of variability in hardness and some don't seem to have the 'give' once the core is reached inside.[/quote]

I have never actually seen a dog that had been given antlers (as chews, I mean!). But, whatever the reason and mechanics, there were too many reliable anecdotal reports of broken teeth. BVDA went so far as to issue a "position statement" about them, not a step undertaken lightly.

RE: nylon bones

Robert FalconerTaylor — Tue, 04 Dec 2018 06:31:02 GMT

[quote user="Evelyn Barbour-Hill"]

Getting into "further discussion" already, but......

is it the literal hardness of an object that makes tooth fracture likely, or some other property? What are the actual mechanics of a dog's upper fourth premolar breaking on a chew? When it's the common buccal slab fracture, it's clearly due to excessive force being applied during the normal gnaw manoeuvre – is it hardness that leads to that excessive force?

[/quote]

Very interesting thread, what are your thoughts on deer antler chews Evelyn? Anecdotally, from what I've seen there does seem to be quite a lot of variability in hardness and some don't seem to have the 'give' once the core is reached inside.

RE: nylon bones

Anthony Todd — Mon, 03 Dec 2018 22:36:55 GMT

RE: nylon bones

Evelyn Barbour-Hill — Mon, 03 Dec 2018 22:29:18 GMT

[quote user="Anthony Todd"]You're getting into the realms of Shore Hardness [look it up][/quote]

I don't need to, thank you Anthony.

RE: nylon bones

Anthony Todd — Mon, 03 Dec 2018 17:53:41 GMT

[quote user="Evelyn Barbour-Hill"]is it the literal hardness of an object that makes tooth fracture likely[/quote]

You're getting into the realms of Shore Hardness [look it up]

RE: nylon bones

Evelyn Barbour-Hill — Mon, 03 Dec 2018 15:03:23 GMT

[quote user="Rob Davis"]ok, you're stretching my limited mechanics knowledge here, but this doesn't feel right. The rubber object moulds to the shape of the tooth as the force is applied, presumably spreading that force over a larger area so reducing the pressure. I suspect it is the reduced pressure which would reduce the likelihood of fracture. Also with the harder, less distortable object the force is applied at a single point in a single direction rather than being dissipated.[/quote]

Yes, fair hypothesis in you last sentence. I don't believe it has anything to do with pressure, though: the tooth does not (often) crush or crumble. In fact dentine is pretty strong in compression. It's when it is stressed in tension or shear that it may get into trouble. (In the context of chews, I mean.)

RE: nylon bones

Rob Davis — Mon, 03 Dec 2018 08:46:51 GMT

[quote user="Evelyn Barbour-Hill"]He is gnawing it: the teeth engage the object, then further force is exerted and the teeth either sink in to the object or scrape across it, depending on its size and nature. But sometimes the force is too much, or maybe applied at slightly the wrong angle, and the tooth gives way instead.[/quote]

ok, you're stretching my limited mechanics knowledge here, but this doesn't feel right. The rubber object moulds to the shape of the tooth as the force is applied, presumably spreading that force over a larger area so reducing the pressure. I suspect it is the reduced pressure which would reduce the likelihood of fracture. Also with the harder, less distortable object the force is applied at a single point in a single direction rather than being dissipated.

RE: nylon bones

Evelyn Barbour-Hill — Fri, 30 Nov 2018 22:23:41 GMT

[quote user="Rob Davis"]

[quote user="Evelyn Barbour-Hill"]is it hardness that leads to that excessive force?[/quote]

If you drop a cup onto a tiled floor it will smash. Drop the same cup onto a vinyl floor and if you're lucky it might bounce. Chuck it on a carpet and it'll be fine.

[/quote]

Yes of course, if the floor's hard it won't dint (well, of course it will slightly even if it's concrete, simple mechanics) and the kinetic energy of the fall pretty well all (apart from the bit that's turned into sound) has to be taken up by the cup, and if it's china the random stresses generated will usually break it. If the floor's soft, the kinetic energy is all taken up by the floor material deforming. A china cup is just as hard as a tiled floor. Drop a stone onto a tiled floor and a tile will crack or chip.

Yes, but....... the dog is not bashing his teeth against the object (well sometimes perhaps he is, and then you get a different kind of fracture). He is gnawing it: the teeth engage the object, then further force is exerted and the teeth either sink in to the object or scrape across it, depending on its size and nature. But sometimes the force is too much, or maybe applied at slightly the wrong angle, and the tooth gives way instead.

RE: nylon bones

Rob Davis — Fri, 30 Nov 2018 18:42:08 GMT

[quote user="Evelyn Barbour-Hill"]is it hardness that leads to that excessive force?[/quote]

If you drop a cup onto a tiled floor it will smash. Drop the same cup onto a vinyl floor and if you're lucky it might bounce. Chuck it on a carpet and it'll be fine.

RE: nylon bones

Evelyn Barbour-Hill — Thu, 29 Nov 2018 22:47:11 GMT

Getting into "further discussion" already, but......

RE: nylon bones

Rob Davis — Thu, 29 Nov 2018 15:04:41 GMT

I tend to advise people that if you can't dent it with your thumbnail, it's probably too hard for your dog to be chewing ok.

RE: nylon bones

Evelyn Barbour-Hill — Wed, 28 Nov 2018 17:01:02 GMT

[quote user="ingavdh"]have bvda position statements disappeared? with nylabones and antlers etc.[/quote]

Ooh. It looks as if they have. I will mention it to the webmeister.

I don't study the marketing of nylon bones.Our thinking generally was that the slightly softer ones were just as likely to break teeth as the original hard ones. I don't know if others have been introduced. I don't care, really, because I recommend rawhide chews or sometimes raw real bones.