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Ozone air levels adjacent to a dental ozone gas delivery system
Umeå University, Faculty of Medicine, Department of Odontology, Dental Hygiene.
Umeå University, Faculty of Medicine, Department of Odontology, Dental Hygiene.
Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
Umeå University, Faculty of Medicine, Department of Odontology, Dental Hygiene.
2007 (English)In: Acta Odontologica Scandinavica, ISSN 0001-6357, Vol. 65, no 6, 324-330 p.Article in journal (Refereed) Published
Abstract [en]

Objective. Ozone (O(3)) has been suggested as an anti-microbial treatment in dentistry, with an ozone gas delivery system introduced for the treatment of fissure and root caries. The aim of this study was to investigate the sealing capacity of the novel delivery system and its re-suction capacity during accidental displacement of the cup at different stages of ozone delivery. Material and methods. Ozone leakage was studied in vitro after application on a flat metal surface and on buccal and occlusal tooth surfaces. An ozone analyzer was used to measure ozone gas concentrations adjacent to the delivering cups when adapted to the target surfaces during and after 10-20 s application cycles. The measured levels were compared with the background concentrations in the room. Measurements were performed 1) after complete ozone application cycles, 2) within the cycle before the start of the suction period, and 3) after displacements of the cup during the cycles. Results. Ozone air values varied between 8 and 166 microg.m(-3) for the flat metal surface and between 0 and 108 microg.m(-3) for the tooth surfaces. Ozone leakage levels were 7.6 microg.m(-3) for the flat and 7.4 microg.m(-3) and 5.6 microg.m(-3) for the buccal and occlusal surfaces, respectively, and 5.2 microg.m(-3) and 9.8 microg.m(-3) for the premolar and molar surfaces, respectively. Cycles with displacement showed significantly higher leakage levels than continuous complete cycles (p=0.03). Conclusions. Ozone application cycles with displacements showed significantly higher leakage levels than continuous complete cycles. The largest ozone delivery cups showed the highest leakage values. A change in background levels was seen with similar change in adjacent ozone levels. The overall measured ozone leakage values were low after normally functioning delivery cycles and after repeated displacements. The delivery system can be considered safe.

Place, publisher, year, edition, pages
2007. Vol. 65, no 6, 324-330 p.
Keyword [en]
URN: urn:nbn:se:umu:diva-16976DOI: 10.1080/00016350701687247PubMedID: 17934889OAI: diva2:156649
Available from: 2007-11-06 Created: 2007-11-06 Last updated: 2012-09-21Bibliographically approved
In thesis
1. Effect of ozone on dental caries and on cariogenic microorganisms
Open this publication in new window or tab >>Effect of ozone on dental caries and on cariogenic microorganisms
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

There are a number of unanswered questions regarding new caries preventive methods such as ozone treatment as well as novel caries detection methods that monitor and evaluate these preventive methods. This thesis seeks answers to some of these questions.

Aims: Paper I investigates the in vitro sealing capacity of a novel ozone delivery system and its re-suction capacity. Paper II studies the in vitro antibacterial effect of ozone on cariogenic bacterial species with and without the presence of saliva and its possible effect on the saliva proteins. Paper III assesses the in vitro validity of laser-induced fluorescence (LF) measurements, visual inspection (colour), and tactile examination (surface texture) on root caries lesions and correlates these with histopathological measurements of lesion depths.  In addition, Paper III investigates how inter-device, inter-examiner, and intra-examiner levels influence LF reading agreements and whether lesion colour and surface texture influences LF readings. Paper IV evaluates the in vivo effect of ozone and fluoride varnish treatments on occlusal caries in primary molars.

Material and methods: Paper I: Full ozone application cycles, including the re-suction period, and interrupted cycles with displacement of the cup during the delivery cycle were studied using an ozone air analyser. Paper II: Ozone gas was exposed to the bacteria in the solution’s buffer and saliva via a tube connected to the ozone generator for 10, 30, and 60 seconds. Paper III: Calibrated examiners assessed lesion colour and surface texture and performed measurements with two LF devices for three separate one-week intervals.  Sections (300µm thick) of 64 out of 93 teeth were obtained and examined under a microscope. Lesion depth was assessed with two references: from the delineated borderline of the original exposed root surface (ref I) or, if loss of surface continuity, the absolute lesion depth (ref II). Paper IV: The split mouth study was conducted in two parts. The participants in part A were children (mean age 4.8 years) with medium-high caries risk. Inclusion criteria were bilateral matched pairs of cavitated or non-cavitated occlusal lesions in primary molars (Ekstrand index score ≤ 3). Children in part B (mean age 4.5 years) with low-medium caries risk had pairs of non-cavitated lesions only (Ekstrand index score ≤ 2a). The assessments and treatments with ozone and fluoride varnish were performed at baseline and at three, six, and nine months. At the 12-month follow-up, only assessments were performed.

Results: Paper I: Ozone leakage levels varied between 5.2 and 9.8 µg/m3. Paper II: In the salt buffer, 92%, 73%, and 64% of the initial numbers of A. naeslundii, S. mutans, and L. casei, respectively, were killed after 10 s ozone exposure and approximately 99.9% of the bacteria were dead after a 60 s exposure. After 10 and 30 s but not after 60 s exposure to ozone, S. mutans and L. casei were less efficiently killed in saliva compared to in the salt buffer. Various saliva proteins were degraded by ozone after the 60 s exposure. Paper III: The correlation between LF readings and histological depth was low with values ranging from 0.22 (p ˃ 0.05) to 0.31 (p < 0.05). The LF devices were significantly correlated with discolouration and with a surface texture denoted as hard. A significant correlation was found between colour and histological depth. No significant correlation was found between surface texture and histological depth. The reliability, evaluated as intra-class correlation coefficient, was 0.99 for intra-examiner, 0.97 for inter-examiner, and 0.98 inter-device level. Large differences were found between two consecutive measurements and high measurement errors indicated considerable deviation of individual measurements.Paper IV: In the first 15 pairs of part A, eight lesions treated with ozone and nine treated with fluoride, including all cavitated lesions, progressed to failure, i.e., required operative treatment during the study time. Due to non-acceptable results, the sample collection was discontinued because of ethical reasons. In part B, of 35 pairs, one of the ozone treated lesions failed at 12 months. A small shift towards increased VI scores was recorded for both ozone and fluoride lesions in this second part.


- The ozone delivery system can be considered a safe system with low leakage levels in air, also with accidental displacements.

- The cariogenic species S. mutans, L. casei, and A. naeslundii were sensitive to ozone gas treatment. The presence of saliva hampered the antibacterial effect of ozone.

A low correlation between the LF readings and the histopathological depth of root caries lesions was shown. The LF device was found not to be appropriate for application to root caries diagnosis.

- Neither ozone nor fluoride varnish treatments arrested the progression of cavitated occlusal caries lesions. In low and medium caries risk children non-cavitated occlusal lesions remained mainly unchanged during the study period.  No difference in the effect of ozone and fluoride varnish treatments on occlusal caries in primary molars was seen.

Place, publisher, year, edition, pages
Umeå: Umeå universitet, 2012. 45 p.
Umeå University odontological dissertations, ISSN 0345-7532 ; 123
Dental caries, Ozone, Cariogenic microorganisms
National Category
Research subject
urn:nbn:se:umu:diva-59066 (URN)978-91-7459-454-6 (ISBN)
Public defence
2013-11-27, Sal B, By 1D, Norrlands universitetssjukhus, Umeå, 09:00 (Swedish)
Available from: 2012-09-21 Created: 2012-09-07 Last updated: 2014-10-08Bibliographically approved

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Johansson, ElisabethHagenbjörk-Gustavsson, Annikavan Dijken, Jan
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