You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Periodontal disease is common in cats with advancing age. Various theories exist about the underlying cause - including the possible role of diet.

A study conducted in feral and domestic cats in Australia * found that there was no statistical difference in the prevalance of periodontal disease between the two groups, however dental calculus scores were significantly higher in domestic cats compared to feral cats. 

The presence of periodontal disease was determined by  measuring :

• gingival recession
• peridontal pocket formation 
• furcation
• tooth root exposure
• alveolar bone loss on radiographs
• presence of calculus

Dental calculus scores were recorded.

The feral cats in the study ate mainly small mammals, birds and sometimes reptiles and insects, whereas the domestic cats ate dry or canned prepared pet foods. The authors concluded that the type of ration may play a role in the build up of calculus but does not protect against periodontal disease.

(* Relationship between diet, dental calculus and periodontal disease in domestic and feral cats in Australia. Clarke DE and Cameron A. Australian Veterinary Journal (1998) 76: 690-693)