Erythropoietin Gel as an Adjunct to Xenograft in the Surgical Management of Intrabony Periodontal Defects. A Randomized Controlled Clinical Study

In the periodontal disease there is an interaction of the biofilm with the immune response of the host which results in an imbalance between bacterial virulence and the host defense causing changes in bone and connective tissue homeostasis .

Armitage's 1999 classified periodontitis to either chronic or aggressive . In 2017, the American Academy of Periodontology (AAP) and the European Federation of Periodontology (EFP) classified the periodontal disease using a new staging and grading system. Staging is determining the severity of the disease and the complexity of treatment of the disease, while grading gives additional data about the biological consideration of the disease, such as analyzing the history for the rate of progression and predicting the risk for further progression.

Periodontitis is classified to four stages ranging from Stage I: Initial periodontitis the clinical attachment level (CAL=1-2mm), Stage II: Moderate periodontitis (CAL= 3-4 mm), Stage III: Severe periodontitis and increased potential for tooth loss (<4), and (CAL ≥5mm), Stage IV: Severe periodontitis with increased risk for tooth loss (≥5) and (CAL≥5mm). Grading is determined by the risk factors like smoking, diabetes, and outcomes of scaling and root debridement. Grade A: Low rate of progression (no CAL loss over 5 years), Grade B: Moderate rate of progression (CAL loss<2mm over 5years), and Grade C: High rate of progression (CAL loss ≥2 mm over 5 years) .

The periodontal tissue break down happens because of both the direct effect of the microbial invasion and the indirect effect of the host immune response, this happens when the bacterial invasion results in bacterial products that cross the junctional epithelium which stimulates the host immune response resulting in tissue breakdown .

Pattern of bone destruction in periodontitis can be horizontal or vertical .Horizontal bone loss appears as an even bone destruction leading to a uniform decrease in the bone height in relation to the teeth. Vertical bone loss results in formation of a triangular area of missing bone, known as triangulation. Vertical bone loss could result in angular defects and intrabony pocket formation which become very challenging in treatment.