Tooth problems can often be triggered by mouth infections and the reverse can be true.
If a guinea pig cannot chew it's food properly because of infections in the mouth, which usually lead to painful ulcers, then the teeth can overgrow because they are not getting the normal hard wear and tear that they were designed for. Conversely, teeth that overgrow for other reasons can press on the tongue or develop sharp edges through uneven wear, opening up lesions in the mouth which can become infected.
More often than not these infections of the mouth are fungal rather than bacterial and the most effective treatment which beats anything that has been licensed for use upon animals is Daktarin oral gel. This is formulated to treat thrush conditions in human babies.
The use of the Bucal pad separator which I described in the dental section is invaluable when mouth infections are suspected. Many vets do not even know what they are and rely upon the otoscope which can only target small areas of the mouth, and some even anaesthetise the animals to get a proper look!.
By using the bucal pad separators the whole of the interior of the mouth can be viewed at a glance. The animal is not stressed or it's very life threatened by such inappropriate use of anaesthesia!.
If you see red, raw patches on the tongue and in other parts of the mouth then they are likely to have got there by becoming infected by fungus or bacteria. If, on the other hand, you see lesions down the sides of the tongue, invariably you will instantly see that the teeth were the root cause of the problem. They will either be leaning inwards at too acute an angle, or they have sharp edge on them and both of these conditions can cause the lesions which are, of course open to infections.
As these infections are more often than not, fungal, the oral gel usually clears them up. If it doesn't then the use of the antibiotic Tribissen for about a week is recommended.
Where necessary, of course, corrective dental work must also be carried out.
The dose for the oral gel is a dab in the mouth three times daily for a week, reduced to twice daily for another week. Sometimes it may be necessary to continue for one more week at the dose rate of once a day.
The Tribissen dosage is 0.5 for five to seven days.
I always put the guinea pig in an empty box for about five minutes after I have given these medicines. That way the medicine gets a better chance of seeping in rather than being swallowed as the animals eats or drinks.