# Applications of Cold Atmospheric Pressure Plasma in Density
## 5 CAPP Application in Cardiology  
Carious dental tissue infected by cariogenic microorganisms is usually removed by using rotating instruments that can cause pain and discomfort to the patient. However, the treatment of carious lesions has been changing in the last years. Minimal intervention dentistry (MID) is one of the proposed alternatives that aims to prevent or paralyze disease's activity [89]. In this context, atraumatic restorative treatment (ART) is one example of MID and it has been used with success [90]. This method shows positive results in the treatment of caries in childhood and injuries in children and elderly [91; 92; 93; 94]. In ART, carious tissue is removed by hand instruments and the restoration is carried out [94]. It has been described that the performance of ART can be improved by the elimination of the cariogenic microorganisms during the cavity's cleaning process carried out before the restorative procedure [95].  
CAPP has been suggested as a promising therapeutic tool in cardiology due to its antimicrobial efficiency [96]. Promising results have been obtained against cariogenic bacteria [97]. [PERSON] et al. [98] were the first researchers to suggest the use of CAPP for the disinfection of caries cavities. The researchers concluded that it represents an efficient technique that promote the disinfection of irregular structures and canaliculi inside the affected tooth. Plasma needles generated by specific devices allow the penetration of reactive RONS inside the dental canaliculi inhibiting the cariogenic microorganisms [98]. In addition, plasma has the advantage to inhibit microbial biofilms, without damaging the normal tissue [28; 97] and without causing hyperaemia, swelling, ulcer or anabrosis, resulted from absence of thermal damage [28; 69].  
Subsequent studies also reported the effect of CAPP against cariogenic microorganisms. [PERSON] et al. [99] analysed the effect of CAPP on free-floating planktonic cells. The treatment with CAPP reduced the counts of _Streptococcus mutans_ in 4-logs after 3 min of exposure. [PERSON] et al. [100] described the inhibitory effect of atmospheric pressure plasma associated with gold nanoparticles on _S. mutans_. The group observed that gold nanoparticles conjugated to the bacterial surface and stimulated by the CAPP affected the bacterial cell wall, suggesting that this association may be a future alternative for caries treatment.  
The inhibitory effect on _S. mutans_ and _Lactobacillus acidophilus_ biofilms grown on hydroxyapatite discs has been observed a few seconds after the CAPP treatment [101]. The study suggested that CAPP deactivation of microorganisms was caused by bombardment of charged or neutral species or an accumulation of electric charge a few seconds after treatment. Recently, the inhibition of a cariogenic multispecies biofilm formed by _S. mutans_, _S. sanguinis_ and _S. gordoni_ by Ar-CAPP was reported [102]. Despite of these positive evidences, studies about the effectiveness of CAPP treatment on polymicrobial cariogenic biofilms is still needed [96].  
CAPP can also improve the conventional restorative methods. It can optimize the adhesion between the tooth and the restorative material [103]. Another study demonstrated that the CAPP induces the polymerization of a dental adhesive by direct and indirect energy transfer [104]. In this sense, CAPP can control the moisture of demineralized dentin surfaces, improve adhesive penetration and the mechanical properties of the adhesive/dentin interface [105].  
Considering all the characteristics and effects of CAPP, the application of this innovative technique can be an alternative for the treatment of caries diseases in the near future, allowing more conservative procedures and improving restorative methods.