Ozone Therapy in Dentistry
Ozone therapy has been used in medicine since the 1800’s. Though ozone therapy has been used for years, it is considered relatively new in dentistry. Christian Friedrich Schönbein, a German-Swiss chemist discovered ozone and is regarded as the Father of Ozone Therapy. In 1896 an ozone generating system was patented by Nikola Tesla. In the 1920’s Dr. Edwin Parr, a Swiss dentist, started to use ozone as part of his disinfection system. In 1950 Dr. E.A. Fisch, a German dentist, used ozonated water for dental procedures and pioneered its use in medicine.  That is just a brief history of the use of ozone. As you can see, it is not a new concept.
Medical grade ozone is a mixture of pure oxygen and pure ozone. The ratio is 0.05% to 5% ozone and 95% to 99.95% oxygen. Ozone inhalation can be toxic to the pulmonary system as well as other organs. Though complications with ozone therapy are rare, in the event of an ozone intoxication, the patient should be placed in a supine position, administer humid oxygen, ascorbic acid, vitamin E, and nacetylcysteine. Due to the risk of embolism, ozone should never be administered intravenously. Contraindications for use of ozone therapy include pregnancy, hyperthyroidism, severe anemia, severe myasthenis, active hemorrhage and glucose-6-phosphate-dehydrogenase deficiency. Ozone has a high oxidative power and effect on bacteria, viruses, and fungi, ozone therapy is indicated in the treatment of 260 different pathologies. Due to the instability of the ozone molecule, medical grade ozone must be prepared immediately before use and can not be stored for future use. 
Now that we have reviewed the history and chemical make up of medical grade ozone, can it benefit dentistry? Ozone therapy has been shown to be effective in treating many dental issues from carious lesions (cavities) to the treatment of Temporal mandibular disorder (TMJ disorder). To better understand how ozone therapy works on different dental diagnosis, I’ll explore each diagnosis individually.
Dental caries (Cavities) – Ozone has been shown to be effective in significantly reducing the levels of Streptococcus Mutans. Though this seems very exciting, there is some restrictions to the success of ozone therapy in reducing the levels of S. mutans. It was found that it is most effective in easily accessible surfaces, the size of the lesion was also found to be a contributing factor. The total number of microorganisms in small non-cavitated lesions showed greater reduction than larger lesions, and lesions closer to the gingival margin. Using ozone therapy, on incipient lesions showed significant promise in arresting the caries process. It is also important to note that if there is a cavitation (hole) in the tooth full restorative procedures are necessary to completely restore the tooth, even if ozone therapy is applied. [1,2]
Periodontics – Ozonated water has been found to inhibit plaque formation and reduce the number of gram negative and gram-positive subgingival pathogens. A comparison of the effectiveness of ozonated water and chlorhexidine on periodontal microorganisms was conducted. This comparison resulted with no comparable difference in effectiveness between ozonated water and chlorhexidine in the reduction of periodontal microorganisms.[1,2] Ozonated water can be used as a pretreatment rinse prior to non-surgical periodontal therapy, during treatment in the ultrasonic water reservoir, and after treatment using a syringe and canula for irrigation of the sulcus. I would like to add that a study published in 2015, found that “irrigation with ozonated water as an adjunctive therapy to SRP produces no statistically significant benefit compared with SRP and distilled water irrigation.” It is quite possible the mechanics of irrigation is the beneficial factor and not necessarily the medicament used.
Endodontics – Enterococcus faecalis is the bacteria believed to be a major causative factor in endodontic disease. In the past, studies have found this bacterium to be resistant to sodium hypochlorite, the most common antimicrobial agent used in endodontic treatment. However, more recent studies have shown sodium hypochlorite effective in the elimination of this bacteria. [3.4] Many studies have been done on the use of ozone therapy during endodontic treatment. In these studies, it was found that ozonated water had the equivalent effect of 2.5% sodium hypochlorite in the reduction of E. faecalis and S. mutans, however, ozonated water was not able to neutralize E. coli and lipopolysaccharides inside root canals. The remaining lipopolysaccharides may lead to biological consequences such as apical periodontitis. Overall the ozone therapy was effective in eliminating most bacteria found in cases of pulp necrosis, but not when the bacteria are organized in biofilm. 
Viral and fungal infections – In fungal infections, ozone has been shown to inhibit cell growth at certain stages. With viruses, ozone disrupts the protein shell of the virus and upsets the reproductive cycle with peroxidation.  With the use of ozonated oil or gas, herpetic lesions have been treated which results in less pain and discomfort as well as accelerated healing process. 
Temporomandibular Joint Dysfunction – A clinical study was conducted to compare the use of ozonated water and saline solution in 30 patients with TMJ internal derangement, in need of arthrocentesis. At the post-operative assessment of pain, there was a significant decrease in the ozone group. However, at the 2-day, 1 week, and 2 weeks follow up there was no significant differences between the two groups. This could be explained by the evidence that ozone has anti-inflammatory and analgesic effects, making immediate pain relief more evident. 
It is possible that ozone therapy in dentistry could become more common, however studies have not shown enough evidence that it is more effective than current techniques used in dentistry. It may become more of an adjunctive therapy. I am an advocate for reducing the overuse of antibiotics, which can create antibiotic resistant bacteria, so the idea that ozone therapy could be used to replace some antibiotic treatments is a very interesting concept. Personally, I am excited to see what the future holds for ozone therapy in dentistry and medicine. We have come a long way in dentistry, and I think we still have a lot to learn.
1. Saraswathi V Naik, Rajeshwari K, Shivani Kohli, Sayyad Zohabhasan, and Shekhar Bhatia. Ozone- A Biological Therapy in Dentistry- Reality or Myth????? Open Dent J. 2016; 10: 196-206. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4911747/
2. Nogales CG, Ferrari PH, Kantorovich EO, Lage-Marques JL. Ozone Therapy in Medicine and Dentistry. J Contemp Dent Pract. 2008 May 1;9(4):75-84. Retrieved from https://pdfs.semanticscholar.org/b868/6ad47c203753fcab2e3680ed8e86995f3b35.pdf
3. Willima C Domb. Ozone Therapy in Dentistry: A Brief Review for Physicians. Tnterv Neuroradiol. Oct; 20(5): 632-636. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4243235/
4. Alaa’ Turki Monawer Algurairy. Efficacy of Sodium Hypochlorite 5.2% on Enterococcus Faecalis and It’s Diagnosis with Antibiogram Isolated from Infected Pulp. EJPMR, 2016, 3(8), 67-72. Retrieved from https://www.ejpmr.com/admin/download/article/MTQ2OTg1NDkwOC5wZGY=
5. Al Habashneh R, Alsalman W, Khader Y. Ozone as an Adjunct to Conventional Nonsurgical Therapy in Chronic Periodontitis: A Randomized Controlled Clinical Trial. J. Periodontal Res. 2015 Feb;50(1):37-43. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/24665871
6. A.M. Elvis and J.S. Ekta. Ozone Therapy: A Clinical Review. J Nat Sci Biol Med. 2011 Jan-Jun; 2(1): 66-70. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3312702
7. Abdullah Hammuda, Mohamed Said Hamed, Eman A El-Sharrawy, Adel Iskandar, Mohammed Ahmed Elsholkamy. Use of Ozone in Temporomandibular Joint Arthrocentesis, Clinical Study. Journal of American Science 2013;9(7). Retrieved form https://www.researchgate.net/publication/259620905_Use_of_Ozone_in_Temporomandibular_Joint_Arthrocentisis_Clinical_Study_Journal_of_American_Science_201397