As per AAP definition, periodontitis is defined as inflammation of the periodontal tissues resulting in attachment loss alveolar bone loss and periodontal pocketing.
In the 1999 AAP classification of periodontal diseases, separate terms were given for chronic and aggressive predontitis. But in recent classification 2017, both the type are clubbed together under the single heading of periodontitis and Staging and Grading are given.
But the terms chronic and aggressive are still clinically relevant and features & differences are still valid. Let us see the different features of chronic and aggressive periodontitis. When do we call a periodontitis case to be chronic or aggressive ?
Age
in chronic periodontitis - affects the adults, children may be affected but very rare.
in aggressive periodontitis - mostly the teenage and young adult population are affected.
Cause
chronic periodontitis - local factors present that is plaque and calculus and other local factors and the destruction is consistent with the amount of local factors present. Presence of sub-gingival calculus is seen here and microbial pattern may be variable.
aggressive periodontitis - the amount of local factors and destruction is inconsistent - familial aggregation and mostly associated with Aggregatibacter actinomycetemcomitans.
And again the presence of genetic susceptibilities is seen in aggressive periodontitis. Hyper-responsive macrophages and presence of PMN(neutrophil) dysfunction is common in cases of aggressive periodontitis.
Rate of progression:
In chronic periodontitis, usually there is slow rate of progression or moderate rate of progression, whereas here - as the name suggests aggressive periodontitis there is a rapid destruction of periodontium. And the periodontal destruction cannot be determined with the help of probing depth alone- therefore we have to see about the clinical attachment loss
And also chronic periodontal disease can be modified or associated with systemic diseases like diabetes or other systemic diseases and Modified by environmental factors like smoking and other factors. Whereas usually aggressive periodontitis patients are clinically healthy, who do not have any apparent systemic illness.
Classification:
Chronic periodontitis can be classified as either localized or generalized - based upon the number of the teeth affected. In localized periodontitis less than 30% of the teeth present are affected whereas generalized greater than 30% of the teeth present are affected. That is if 32 teeth are present 30 percent of the 32 teeth is approximately 9 teeth. Therefore if more than 9 teeth are affected it is generalized chronic periodontitis, if less than 9 teeth are affected it is localized chronic periodontitis.
Similarly in aggressive periodontitis also we have this localized and generalized classification but the factor which determined in chronic i.e, 30% will not be applicable here. In localized aggressive periodontitis we have the incisor and molar involved - permanent central incisors and first molars involved) in iopa we can characteristically see vertical or arc-shaped bone loss since only those two teeth are involved, apart from these two teeth may be one more teeth can have a clinical attachment loss.In generalized aggressive periodontitis, more than three teeth are involved.
In localized aggressive periodontitis the serum-antibody response for microbial factor is high whereas generalized aggressive periodontitis has a very poor response and the disease is of intermittent nature - may present in episodes in generalized aggressive periodontitis.