## 5 Diagnostic and Therapeutic Implications  
Periodontal diagnosis is conducted according to the classification system established at the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions [1]. This diagnostic process involves four key steps:  
1. Identification of patients suspected of having periodontitis;
2. Confirmation of the diagnosis of periodontitis;
3. Staging of the periodontitis case;
4. Classification of the periodontitis case.  
The management of dental plaque-related diseases mainly involves nonspecific plaque removal through various means. According to the European Federation of Periodontology (EFP), the first step in therapeutic intervention is to induce behavioral change, motivating the patient to effectively remove supragingival dental biofilm and control risk factors. This initial phase may include the following interventions: the control of supragingival dental biofilm; strategies to improve oral hygiene effectiveness, including motivational techniques and oral hygiene instructions (OHIs); adjunctive therapies targeting gingival inflammation; professional mechanical plaque removal (PMPR), which involves interventions to remove supragingival plaque and calculus, as well as address plaque retention factors that may compromise oral hygiene practices; and risk factor management, which includes interventions to eliminate or mitigate risk factors that contribute to the onset and progression of periodontitis.  
The second phase of periodontal therapy, known as cause-related therapy, is primarily aimed at controlling and reducing subgingival biofilm and calculus through subgingival instrumentation.  
This phase may also involve adjunctive therapeutic measures, including the use of physical or chemical agents, host modulation therapies (administered either locally orsystemically), and local or systemic subgingival antimicrobial treatments. Among recent advances, injectable platelet-rich fibrin (i-PRF) has emerged as a promising adjunct. As demonstrated in a systematic review by [PERSON] et al. [90], i-PRF exhibits significant bactericidal effects against _P. gingialis_ and serves as a regenerative agent due to its ability to release growth factors and extracellular matrix components of connective tissue [91].  
Additionally, hyaluronic acid (HA) and various re-epithelializing agents, including cytokines and growth factors, have been shown to positively influence epithelial-connective tissue interactions. HA, in particular, has demonstrated anti-inflammatory, angiogenic, and osteoinductive properties, promoting cell migration, proliferation, and extracellular matrix synthesis--key processes in tissue repair and healing [92].  
Diagnostic methods for detecting _P. gingialis_ typically involve the analysis of subgingival plaque samples. Commonly used techniques include the following [93]:  
* Enzyme-linked immunosorbent assays (ELISAs);
* DNA probes;
* Real-time polymerase chain reactions (PCRs).  
However, subgingival plaque-based diagnostic tests have shown limitations due to factors such as low sensitivity and specificity, prolonged development times, and the need to send samples to external laboratories for analysis, which limits their practical application in point-of-care settings [94].