Ozone is a great oxidizing agent found in nature as a trivalent oxygen (O3). It is a colorless gas with a strong smell. It exists at the ground level as an air pollutant and a constituent of metropolitan smog, as well as in the Earth’s upper atmosphere, in the stratosphere, as a naturally defensive layer from ultraviolet rays. Ozone therapy is suggested in the management of deep dental caries, Early Childhood Caries (ECC), molar incisor hypo-mineralization (MIH)C, MIH, root canal therapy, remineralization, dental hygiene, and dental prophylaxis, in young children and uncooperative pediatric patient. The main forms of application are gaseous ozone, ozonated water and ozonated oil.
1. Introduction
Ozone is a great oxidizing agent found in nature as a trivalent oxygen (O
3). It is a colorless gas with a strong smell
[1]. It exists at the ground level as an air pollutant and a constituent of metropolitan smog, as well as in the Earth’s upper atmosphere, in the stratosphere, as a naturally defensive layer from ultraviolet rays
[2].
The positive therapeutic effects of ozone and its derivatives, oil and ozonate water, have been investigated in several fields of medicine, since the XIX century.
The main health benefits of ozone therapy include the following:
-
inactivation and elimination of pathogens: Gram-positive and Gram-negative bacteria, fungi, and viruses;
-
stimulation of immune system and improvement of circulation;
-
decrease in inflammation and pain;
-
stimulation of humoral anti-oxidant system;
-
restoration of appropriate oxygen metabolism;
-
prevention of shock and stroke injury;
-
induction of friendly ecological environment;
-
increase in brain function and memory activities
[3].
Ozone does not act directly through traditional drug–receptor pathways and, depending on the method of administration, different hydrophilic (mainly hydrogen) and lipophilic (mainly alkanals) small peroxide molecules will be produced (
reactive oxygen species (ROS
) and lipid oxydation substances (LOPs)) and LOPs). These molecules specifically interact with protein moieties, controlling their epigenetic biological activities, acting on gene expression, enzyme activity, or cellular signals too
[4].
Nevertheless, there is restricted agreement in the scientific community on its use and benefits; moreover, ozone cannot be useful, or it can even be toxic, if it is not used correctly
[5]. There has yet to be a consistent and concord evaluation of the outcomes because of the need for more standardization of the treatment operating procedures (modality of administration, time of exposure, and dosage)
[4].
The therapeutic use of ozone has been suggested for a very long time in dental fields—from 1980 until now—for its antimicrobial, virucidal, and disinfectant properties. It is biocompatible and has immunostimulant, anti-inflammatory, and analgesic properties, promoting tissue regeneration
[3][6][7][3,6,7]. Ozone has shown positive effects in general dentistry for sterilization of equipment, management of surgical wound healing, dental caries and preventive conservative, gingivitis and periodontitis, oral lichen planus, halitosis, post-surgical pain, osteonecrosis of the jaw and prevention of post-extraction alveolitis, plaque and bio-films’ formation, root canals’ disinfection, reducing dentin hypersensitivity, controlling temporomandibular joint disorders, and enhancing teeth whitening
[2][4][7][8][9][10][11][2,4,7,8,9,10,11].
Dental treatment in children is complex and modern technologies must support the practitioner to improve the approach and enhance prognosis with young patients, uncooperative children, or even patients with special needs
[6][8][6,8]. Ozone therapy is a conservative and minimally invasive method—a relatively low-cost and painless treatment that could improve patient acceptability and compliance with a low risk of adverse effects
[3].
At this time, a literature review about the field of application in paediatric dentistry has not been performed.
Pediatric clinicians are interested in improving and extending the dental practice of oxygen-ozone therapy and, at the same time, it could be interesting, for research groups too, to address the knowledge gaps related to less studied research protocols.
2. Form of Application
Because of its instability, ozone has a strong oxidation potential, 1.5 times greater than chloride
[5], which has led its use in medical and dental fields
[12][13][14][55,56,57]. It is not possible to store ozone over prolonged periods—it has a half-life of 40 min at 20 °C
[15][24]. Therefore, it must be arranged closely before use, although the association of O
3 with a vehicle with aqueous properties or viscous properties promotes or retards the conversion into oxygen
[3]. The generator of ozone produces it from pure oxygen, passing through a high voltage gradient of 5 to 13 mV
[2][15][2,24].
There are ozone generators that can produce ozone gas via an open system or a sealed suction system. There are adverse effects that may arise in an open system upon inhalation, so the sealed suction system is usually preferred
[16][18]. When the application of ozone takes place within a closed circuit, ideal airtightness is compulsory for the application of ozone, ensuring no gaseous escape. Silicon cups of distinct size could be used. The concentration of ozone provided to the tissue is about 2100 ppm
[17][12].
Ozone generators that produce ozone via an open system use a glass probe formed by a double glass camera and a mix of noble gases emitting electromagnetic energy. When the probe tip meets the body surface, emission of the energy all around the operation field begins. The ozone generated in the area of operation is 10 to 100 μg/mL
[17][12]. It can be used in areas that are challenging to reach. The concentration of ozone produced from generators is not uniform for the different machines and change in the different programs. From 10 to 100 μg/mL, the flow rate is from 30 to 1000 mL/min. The application time proposed in the different protocols is from 30 s to 5 min.
[18][25].
Ozonated water is used as a mouthwash or in irrigation solutions
[16][18]. As the half-life of ozonated water is only about 20 min, because of which it degrades back into oxygen, its effectiveness must be assured by using it within the first 5–10 min after production
[3]. It is not toxic for use and no negative gastrointestinal effects have been found from its ingestion
[19][26]. When using bi-distilled water and a high-quality ozone generator, a minimum saturation of 4 μg ozone/mL and a maximum saturation of 20 μg ozone/mL, at room temperature, can be obtained
[4][18][20][4,25,27].
Ozonated oil can be convenient and offer greater permeation
[2] and, because the oil remains in contact with the surface for a longer period, it exercises its functions for a longer period
[21][28]. Clinicians can administer ozone in the form of oil, commercially available as ozonated olive oil or ozonized sunflower oil
[19][26]. Ozonated oil’s peroxide value is unclear
[18][25].
The form of administration of ozone differs for dosage of production of its derivate and the clinician must keep in mind that all of the effects are linked to the relationship between reactive oxygen species (ROS) and lipid oxydation substances (LOPs) produced after the interaction between ozone with blood, tissue or serum. Specific oral pathological conditions require specific protocols in treatment
[22][23][24][58,59,60].