Ozonized hydrogels for clinical and domiciliary management in periodontal regenerative therapy an annotation

1 Introduction

Periodontitis is a common disease of the oral cavity consisting of inflammation of the tooth supporting tissues, primarily caused by accumulation of complex polymicrobial dental plaque. It is initiated by Gram-negative tooth-associated microbial biofilms that elicit a host response, resulting in progressive, irreversible bone and soft tissue destruction, tooth mobility and exfoliation [1].

Mechanical debridement, the most commonly used treatment modality in the management of periodontal disease has been quite successful in treating the majority of patients but carries a greater risk of recurrence when used alone, specifically in cases with systemic co-morbidities [2, 3]. It has also been suggested that complete removal of plaque and calculus by mechanical debridement in inaccessible areas including deep pockets (more than 5 mm) and furcation areas is difficult, thereby leading to significant treatment failure rates [4].

Since, scaling and root planing alone is insufficient to eliminate bacteria from the periodontal pocket, especially in inaccessible areas, antibiotics (both systemic and local) have been used as adjunctive agents in the management of periodontal disease for many years [2]. However, the repeated, long-term use of any systemic antibiotics may lead to potential complications, including risk of resistant strains, superimposed secondary infections, and possible lack of patient adherence [5].

Since, periodontitis is a localized disease, local treatment is preferred over systemic therapy to avoid the complications associated with systematic administration of antibiotics. The key to success for periodontal therapy depends on the selection of an appropriate antimicrobial agent with appropriate route of drug administration. Minimal side effects to local drug delivery (LDD) and good patient adherence are other potential advantages compared to the systemic therapy [1, 2, 5]. Various studies have revealed that LDD into the periodontal pockets can provide higher therapeutic concentrations of the antibiotic compared to the systemic administration. Local antibiotics including, tetracycline (TET), doxycycline (DOX), minocycline (MIN), metronidazole (MTZ), chlorhexidine (CHX), clarithromycin (CLM), azithromycin (AZM), moxifloxacin (MXF), clindamycin (CLI), and satranidazole (SZ) are presently being used in various drug delivery systems such as irrigations, fibres, films, injectable, gels, strips, compacts, vesicular liposomes, microparticles, and nanoparticle systems in the management of periodontal disease [6].

Over the last few years, the use of ozone in medicine has significantly raised due to its recognized properties. Several in vitro studies have shown wide antibacterial activity for ozonized vegetable oils against microorganisms, such as bacteria, virus, protozoa, and fungi [1]. In addition to that, ozone shows immunomodulatory, anti-hypoxic, biosynthetic, and anti-inflammatory properties which justifies its several applications, both in orthopaedics and dentistry [2]. As regards the latter, ozone therapy has been used to manage wound healing, dental caries, oral lichen planus, gingivitis and periodontitis, halitosis, osteonecrosis of the jaw, post-surgical pain, plaque and biofilms, root canal treatment, dentine hypersensitivity, temporomandibular joint disorders, and teeth whitening [2], and to functionalize implants surfaces for dental and orthopaedic clinical uses. Considering the abovementioned applications, the use of ozone for the treatment of gingivitis and periodontitis appears quite interesting for clinicians.

2 History

Ozone (O3), is found in nature, in the form of a gas in the stratosphere in a concentration of 1-10 ppm, being continually created from and destroyed into molecular O2. It is one of the most important gases in the stratosphere due to its ability to filter ultraviolet rays, which is critical for the maintenance of biological balance in the biosphere. The German Chemist Christian Friedrich Schonbein is considered to be the father of ozone therapy (1840). When he passed an electric discharge through water, a strange smell was produced, which he called ozone, from the Greek word ozein (odor). In dentistry, Dr. E.A. Fisch (1889–1966) was the first dentist to use ozonated water in his practice. Joachim Hansler, a German physicist, joined Hans Wolff, another German physician, to develop the first ozone generator for medical use.

The main use of ozone in dentistry is that it relays on its antimicrobial properties. It is proved to be effective against both Gram-positive and Gram-negative bacteria, viruses and fungi [7]. In periodontology, it has been used for gingivitis, periodontitis, peri-implantitis, surgical cuts, prophylaxis. Ozone can be used in various forms for treatment of periodontal disease: Ozonated water, ozonized oil, and gaseous ozone [8].

Chlorhexidine (CHX) is considered the most widely used adjunctive antiseptic in periodontal treatment and it is the “gold standard” agent for chemical plaque control methods, as it is a broad-spectrum antiseptic. The results of Mariotti and Rumpf; Mohammedi suggested that the substantivity of chlorhexidine lasts for up to 12 weeks, moreover, even low concentrations of CHX may be toxic to gingival fibroblasts, thereby reducing the production of collagen and non-collagen proteins and potentially delaying periodontal healing. Furthermore, an increasing number of immediate-type allergies to this agent have been reported, including contact urticaria, occupational asthma, and anaphylactic shock. Because of the possible dangerous allergic reactions to CHX, topical usage of this drug, particularly to mucous membranes, is restrained [8].

Ozone is now being regarded in dentistry as a possible alternative antiseptic agent. Ozone has effective antimicrobial activity against bacteria, fungi, protozoa, and viruses and does not induce microbial resistance. Recent researches have reported antimicrobial effects on oral pathogens of both gaseous and aqueous forms of ozone, and the effectiveness of ozone in the treatment of oral diseases is now a topic of deep research. Additional reports have indicated that aqueous ozone is extremely biocompatible with fibroblasts, cementoblasts, and epithelial cells, suggesting that aqueous ozone would be valuable in treating oral infectious diseases such as periodontal disease, apical periodontitis, and periimplantitis [9]. Ozone can be used in several forms for treatment of periodontal disease: Ozonated water, ozonated oil, and gaseous ozone and more newer ozone gels.

Lot of literature supports the evidence for ozone being a healer for gingivitis and better substitute because of less toxicity. Inspite, of knowing so many advantages and broad-spectrum antimicrobial activity still it is not utilized that greatly. The present article highlights the advantages of ozone over the gold standard chlorhexidine. The chlorhexidine gel is being used as local drug delivery (LDD) agent inspite of knowing that the long-term use can lead to cytotoxicity. The notion arises that why cannot we use ozone gel as a potential LDD agent.

3 Review of literature

Recent researches have reported antimicrobial effects on oral pathogens of both gaseous and aqueous forms of ozone, and the effectiveness of ozone in the treatment of oral diseases is now a topic of deep research. Additional reports have indicated that aqueous ozone is extremely biocompatible with fibroblasts, cementoblasts, and epithelial cells, suggesting that aqueous ozone would be valuable in treating oral infectious diseases such as periodontal disease, apical periodontitis, and periimplantitis. The ozone therapy in gingivitis, periodontitis and periimplantitis has proven to ensure good results with lack of cytotoxicity.

4 Marginal gingivitis

Priya et al. [10] performed a split-mouth study in 28 patients with fixed orthodontic treatment by irrigating one quadrant of the mouth with 900 mL of ozonated water and the other with saline solution. By evaluating the gingival crevicular fluid patients for up to 4 months, they concluded ozone was able to reduce aspartate aminotransferase significantly and improving gingival index, thus reducing inflammation. The test area was irrigated with ozonated water through ozone water jet set in a mode so that it equalizes with the air water syringe pressure. A total of 900 ml of ozone water was used to irrigate on test side and same quantity of saline irrigation was used on the control side each time. The authors gave no information about ozone concentration.

Sandra et al. [11] conducted a split-mouth study by irrigation one quadrant with 0.2% chlorhexidine solution and the other with ozonated water for 15 seconds. Reassessed 14 and 28 days after the irrigation, patients treated with a single ozone irrigation had a significant clinical improvement compared to those treated with chlorhexidine. The adopted experimental conditions are 0.01 mg/L ozonated water that was released from a dental jet at an ozone output of 0.082 mg/h, a noise output.

Parkar et al. [12] irrigated the mouth of patients with chronic gingivitis with water, 0.2% chlorhexidine and ozonated water. After a 15-days follow-up, despite chlorhexidine had shown a greater improvement in reducing plaque, ozonated water proved to be equally effective. The authors do not give information on the concentration of ozone.

Al-Chalabi and Mohamed [13] treated patients with gingivitis induced by plaque with chlorhexidine gel and ozonated gel, immediately after the scaling. After 7 days, it was observed that both gingival crevicular fluid volume and IL-1β concentration were significantly lower in the ozone gel group. Ozone gel directly reacts with the bacterial plaque allowing it to exert its optimal bactericidal effect during exposure and subsequently reduce gingivitis. Neither information about ozone concentration nor time of application of the treatment are provided.

5 Periodontitis

Dengizek et al. [14] performed scaling and root planing (hereafter referred to as SRP) in 40 patients with chronic periodontitis and randomly treated them with: gaseous ozone in the gingival sulcus for one minute; or placebo. Two applications were performed in a period of 4 days. Ozone showed no statistical differences when compared with placebo in plaque index, gingival index and probing depth. Ozone was applied to the periodontal pockets in accordance with the manufacturer’s protocol. No specifications about ozone were given, except for the likely indication of the program adopted. On the other hand, Abreu et al. combined diverse ozone applications to treat periodontitis in 50 patients, which were divided into 5 groups, that received: gaseous ozone (3 seconds in each pocket); ozonated oil (2 drops in each pocket, twice a day by the patient itself); ozonated water (20 mL in each pocket – weekly during a month); ozonated water + gas + oil; and the conventional treatment, with saline solution. Clinically, all the groups treated with ozone improved in the first month, especially the one with combined therapies. Besides less gingivorrhagia and decrease of depth of probe, after 6 months, the number of pathogens dropped to less than detectable. It was concluded that combined modalities of ozone therapy were more efficient in treating periodontitis.

Saglam et al. [15] evaluated histopathological and immunohistochemical changes in 3 groups of rats with periodontitis, treated with: systemic gaseous ozone injected intraperitoneally at a concentration 0.7 mg/kg; topical gaseous ozone for 30 seconds; no treatment. Both treatments were performed every two days, for 14 days. Two days after the last application, the rats were sacrificed. Both ozone applications were equally effective on reducing periodontitis in rats. The topical ozone application was performed describing the modalities of a commercial ozone generator (Ozone DTA, Apoza Enterprise Co., New Taipei, Taiwan).

Hayakumo et al. [16] performed a double-blind study with 22 patients with chronic periodontitis to a treatment with mechanical debridement with ultrasound, using ozone nanobubble water. The placebo group was treated only with water. Despite a significant reduction on number of bacteria after 8 weeks in ozone group, there was no significant improvement in clinical analysis and it was concluded that, despite the benefits were minor and of unknown clinical significance, ozone could be adjunct to periodontal treatment. Ozone nanobubble is stabilized over a long period in aqueous solution and the method to prepare them is protected by patent. The ozone concentration of 1.5 mg/L is provided. Cosola et al. divided 28 orthodontic patients with brackets and arch wires both in the 2 groups: control, which received traditional oral hygiene session + 0.05% chlorhexidine mouthwash twice a day; and ozone group, with besides traditional hygiene session, received also ozonated water. After one month, ozone had more improvement in plaque index and bleeding on probe score, when compared with chlorhexidine. Patients were instructed to use ozonated water mouthwash twice a day, through a device that delivered ozone at 50 mg/h (20°C) and a mass flow rate of 0.2 L/min.

In contrast, Al Habashneh et al. [17] irrigated the pockets of 41 patients with periodontitis with ozonated water or distilled water for 30-60 seconds. After 3 months, despite a significant improvement in clinical parameters before and after treatment, no significant differences were observed between ozone and control group. A detailed aqueous ozone preparation method is reported by treating bi-distilled water with gaseous ozone (75–85μg/mL) for 10–15μg/mL using a commercial ozone generator (Hypernedezon Comfort, Iffezheim, Germany), resulting in a final ozone concentration in water of about 20μg/mL. Corroborating, Kshitish and Laxman [18] performed a split-mouth study by treating 16 patients with chronic and aggressive periodontitis with oral irrigation of ozonated water or 0.2% chlorhexidine for 4 days and after 18 days. Ozone showed higher potential in plaque and bleeding index reduction when compared to chlorhexidine. A detailed description of the irrigation and ozone output of 0.082 mg/h at a water outflow of≥450 mL for a total time of 5–10 min is reported.

After SRP, Niveda and Malaiappan [19] irrigated with ozonated water the mouth of patients with chronic generalized periodontitis. The plaque samples collected from the patients who received ozonated water was significantly lower anaerobic bacterial load comparing to those who received distilled water. The final concentration of ozone in the water is missing.

On the other hand, Vasthavi et al. [20] performed ozonated water subgingival irrigation for 30–45 seconds after SRP in patients with chronic periodontitis. The control group was irrigated with distilled water. By evaluation and samples collected at baseline and after 14 and 21 days and 2 months, they observed both groups improved clinical and microbiological analysis, comparing to baseline, but no significant differences between them. Similar results were found by Dodwad et al. [21], that treated patients with chronic periodontitis with ozonated water at baseline, 1 and 4 weeks after. In comparison with 0.2% chlorhexidine and povidone iodine, patients treated with ozone had a higher reduction in gingival and plaque index and pocket probing depth. Besides, all three therapies had similar results in bacteria reduction. After SRP on patients with chronic periodontitis, Issac et al. [22] performed an ozonated water subgingival irrigation for 60 seconds each pocket. The treatment was made at the first, second and third week. The last evaluation happened on the fourth week. Comparing to baseline and to the control sites, ozone irrigation improved clinical and microbiological parameters. All the authors gave no information about ozone concentration. Instead, Tasdemir et al. [23] treated patients with generalized periodontitis with gaseous ozone application into periodontal pockets for 30 seconds twice a week for 2 weeks. For this, a split-mouth study was performed and the patients were reassessed after 3 months. All the biochemical parameters were lower after the follow-up, but only pentraxin-3 decrease was statistically significant. All periodontal parameters had improved, but no significant difference was observed between two sides.

Vadhana et al. [24] used freshly prepared ozonated sesame oil against S. mutans. For this, 75 teenagers were recruited. After an oral prophylaxis, the participants rinsed with 10 mL ozonated sesame oil (OSO), sesame oil (SO) itself or 0.12% chlorhexidine mouthwash every weekday for 15 days. Before the treatment, and after 15 and 30 days, salivary samples were collected. Despite showing significant reduction in the S. mutans count in all the groups after 15 days when compared to baseline, after 30 days, only SO and OSO had a statistically significant reduction. Parallel, an in vitro trial tested the same agents above in agar well-diffusion seeded with S. mutans. While none inhibition was observed in the sesame oil group, chlorhexidine group has the greatest zone of inhibition. The authors state that “ozonated sesame oil was prepared by passing ozone gas through commercially available sesame oil using ozone generator, whose output was titrated to 2 g/h for about 2 min to adjust the concentration of ozone to 0.01 ppm”. Patients with aggressive periodontitis were treated with ozonated olive oil gel by Shoukheba & Ali. [25] Subgingival administrations were performed immediately after SRP and 7, 14 and 21 days after SRP. After one month, there was an improvement in all clinical parameters in patients treated with ozonated oil gel. After 3 and 6 months, the improvement was minor, thus still significant comparing to control group. The brand name of the commercial ozonated olive oil gel (Oxactiv gel, Pharmoxid Arznei GmbH&Co., Iffezheim, Germany) has been mentioned.

Gandhi et al. [26] selected patients with periodontitis to perform a split-mouth study, where two quadrants were treated with SRP and 0.2% chlorhexidine and the other two were treated with SRP and ozonated oil, applied subgingivally immediately after the SRP and after 2 weeks. Upto, 3 months, both groups demonstrated significant clinical and microbiological improvements when compared to baseline, but no difference was observed between the group concluding ozone is equally effective as chlorhexidine and had no side effects. No information about ozonated olive oil has been given.

6 Discussion

Antimicrobial agents have been administered both systemically and locally. Systemic administration usually indicated as an adjunct to scaling and root planing in order to prevent the recolonization of pathogenic bacteria. It is administered for a period of 7 –14 days. But it requires a higher concentration to be administered every few hours in order to stabilize the effective dose level. It may lead to adverse effects like hypersensitivity reaction, GIT disturbances, and bacterial resistance. These adverse effects would markedly reduce if the antibiotics applied locally. So local drug delivery used as an adjunct to scaling and root planing and as aids in the control of growth of pathogenic bacteria.

According to Greenstein and Tonetti, local drug delivery must fulfil the following criteria [27]

It must reach the intended site of action.

When placed into the periodontal pocket they reduce the probing pocket depth, subgingival bacterial flora and clinical signs of inflammation. The advantages of this method included that it can reach the base of the periodontal pocket which is inaccessible to mouth washes and causes sustained release of short dose of drug over a long period of time. It has been found that local drug delivery can attain a 100-fold higher concentrations of antimicrobial agents in subgingival sites. It does not have any effect on nearby structures such as tonsils, buccal mucosa etc which may cause the chance of getting reinfection. Local drug delivery can be safely used in medically compromised patients for whom periodontal surgery is contraindicated and for periodontal maintenance therapy.

One of the main problems faced while using local drug deliver is the difficulty in placing therapeutic concentrations of antimicrobials into deeper pockets and furcation lesion. The antimicrobial agents that have been used as local drug delivery in the treatment of periodontal disease may be sustained release or controlled release. In sustained release, drug delivery is for less than 24 hours where as in controlled release, drug delivery is for more than 24 hours.

Various antimicrobial agents used are:

Tetracycline

Chlorhexidine being considered as the gold standard. It is used as anti-fungal and anti-bacterial agents. It is available in the form of mouth rinses, gels, varnishes, and chip to be used as a local drug delivery agent. It acts by binding to anionic acid groups on salivary glycoproteins thus reducing pellicle formation and plaque colonization and by binding to salivary bacteria and interfering with their adsorption to teeth. Chlorhexidine has been shown to be an effective agent in plaque inhibition. It is well retained in the oral cavity, the reacting reversibly with receptors in the mouth due to its affinity for hydroxyapatite and acidic salivary protein. Its antibacterial action is due to an increase of the cellular membrane permeability followed by the coagulation of intracellular cytoplasm macromolecule. Chlosite gel is an agent containing 1.5% chlorhexidine of xanthan type. Xanthan gel is a saccharide polymer, which constitutes of a three-dimensional mesh mechanism, which is biocompatible and a good local drug delivery agent. Chlosite undergoes a progressive process of imbibition, and gets physically removed from the application site within 10 to 30 days.

Ozoral pro gel (Innovares) is a, mucoadhesive oral hydrogel containing 15% of ozonized sunflower seed oil, named Ozonia 3000 Sunflower. Ozonia 3000 Sunflower is manufactured, titrated (test method ISCO3), standardised and stabilised. It enhances tissue repair processes as well as promotes a healthy oral environment, with particular emphasis on gingival and periodontal pockets and cavities. Ozoral is suitable for the treatment of eroded, damaged or inflamed areas, outcomes of oral surgery and iatrogenic damages in general (thrush, periimplantitis, periodontitis, gingivitis, stomatitis caused by prostheses, lesions caused by orthodontic braces; insult due to tartar removal, root scaling, root planing, etc.).

7 Future perspective

Future studies on the ozone gel can be helpful for establishment of link for using it locally as well as delivering into the periodontal pockets.

8 Conclusion

In conclusion, it is essential to deliver health services that meet quality criteria, reporting aspects related to safety, effectiveness, timeliness, patient-centredness, efficiency and equity. The possibility of comparing the multiple and sometimes conflicting results obtained according to the types of treatment represents such a standardization effort. Different treatment conditions may require specific treatments. Therefore, one dosage may be suitable for obtaining a certain therapeutic response, but it may not be sufficient for another condition, based on the complexity and multiple activities of ozone and its derivatives [28]. In future, case reports, case control studies, systematic reviews are required to establish the hypothesis that ozone gel could be a promising local drug delivery (LDD) agent and act better on anaerobic organism than the gold standard chlorhexidine gel as LDD.