## 4 Discussion  
Over the years, the primary treatment of periodontal diseases has remained constant, comprising the mechanical removal of dental biofilm and calculus by scaling and root planing [8]. However, not all patients might respond to mechanical debridement only [9]. Therefore, antibiotics have been prescribed as an adjunct, albeit prolonged use of these antimicrobials mainly CHX as an adjunct to mechanical plaque reduction can result in a wide range of systemic and local adverse effects, such as tooth staining, taste alterations, burning sensation, and the growth of bacterial resistance [24]. Notably, in this study, CHX has been used as a positive control, and it is apparent that CHX with lower concentration has great antimicrobial and antibiofilm effects against clinically isolated periodontal pathogens. Further, this confirms the importance of using CHX as an adjunct to periodontal therapy. However, chronic use of CHX is associated with the above adverse effects. Thus, finding an alternative to CHX warrants deeper investigation. Figure 7: Represents the antibiofilm activity of the FEO against **(A)**_P. gingivalis_ and **(B)**_P. internedia_. The intensity of the violet color on the test tubes from left to right (tube 1 to tube 10) represents the amount of biofilm formation by the clinical isolates. Concentrations are in \(\mu\)L/mL, while the test tubes labeled CHX and MHB are (+) and (\(-\)) controls, respectively. It is important to acknowledge that, to the best of our knowledge, this is the first in vitro study to evaluate the antibacterial and antib biofilm activities of _CEO_ and _FEO_ against the clinically isolated _P. gingialis_ and _P. intermedia_. However, many studies have examined the antimicrobial activity of _CEO_ and _FEO_ against other pathogenic micro-organisms [13]. The results of this present study revealed that _CEO_ has comparable antibacterial and antib Biofilm activity against the clinical strains compared to CHX, especially at higher concentrations. Furthermore, _FEO_ produced smaller inhibition zones against clinical strains than CHX 0.12% at all concentrations used in this study, while wider bacterial growth inhibition zones were measured at the highest oil concentration when compared to lower concentrations. Generally, natural products like eOs are safer with fewer adverse effects than synthetic antimicrobial agents [25]. Therefore, higher concentrations might be used in future experiments to identify these natural compounds' effective doses and use them as an alternative to systemic and local antimicrobial agents in periodontal therapy. In agreement with our results, another in vitro study also revealed similar antibacterial and antib Biofilm activities of _CEO_, with fewer adverse effects than CHX against _Streptococcus mutans_ (_S. mutans_) and _Streptococcus pyogenes_[26]. Other studies tested the antibacterial effect of fennel seed methanolic extract against the cariogenic bacteria _S. mutans_, compared it with CHX 0.2%, and found that CHX was more effective and produced a more significant inhibition zone [27; 28]. Furthermore, other researchers found that chewing the seeds for five minutes showed a rise in salivary pH that can prevent demineralization and have an anti-cariogenic property [29]. In this current study, the clinically isolated _P. gingialis_ and _P. intermedia_ were sensitive to the _CEO_ with mean MICs of 3.125 \(\mu\)L/mL and 0.195 \(\mu\)L/mL, respectively. Further, the MBCs of the oil against clinical strains were 6.25 \(\mu\)L/mL and 0.195 \(\mu\)L/mL, respectively. Furthermore, according to the results, the _CEO_ was more potent than _FEOs_ against _P. intermedia_, with wider inhibition zones and lower MIC and MBC values. Moreover, the antibacterial efficacy of _CEO_ on caries-producing S. mutans with MIC and MBC concentrations of 62.5 ug/mL was reported. However, another study reported 0.62 mg/mL and 1.25 mg/mL of cumin seed alcoholic extract as MIC and MBC, respectively, against _S. mutans_[30]. In addition, [PERSON] et al.