Note from the National Guideline Clearinghouse (NGC): The National Institute for Health and Clinical Excellence (NICE) commissioned an independent academic centre to perform a systematic literature review on the technology considered in this appraisal and prepare an assessment report. The assessment report for this technology appraisal was prepared by the Aberdeen Health Technology Assessment Group (see the "Companion Documents" field).
Search Strategy
Initial database searches were undertaken to identify relevant systematic reviews and other evidence-based reports. Several Web sites were also consulted to obtain background information. Full details of the main sources consulted are listed in Appendix 1 of the systematic review companion document.
Electronic Databases Searched
- Medline/Embase/Medline Extra multifile search:
- Medline: 1966-May Week 1 2004
- Embase: 1980-Week 20 2004
- Medline: Extra 17th May 2004
- Science Citation Index: 1981-16th May 2004
- Biosis: 1985-12th May 2004
- Amed: 1985-May 2004
- Cochrane Controlled Trials Register (CCTR): Cochrane Library, Issue 2 2004
- National Research Register (NRR): Issue 2, 2004
- Current Controlled Trials (CCT): 18th May 2004
- Clinical Trials: 18th May 2004
- SCI Proceedings: 1991-May 15th 2004
- Conference Papers Index: 1982-May 2002
- ZETOC Conferences: 1993-May 2004
- IADR Meetings abstracts: 2002-2004
Electronic searches were conducted to identify published and unpublished studies on the clinical and cost-effectiveness of ozone therapy for dental caries. The electronic databases searched are detailed above. Full details of the search strategies are documented in Appendix 1 of the systematic review companion document. It was anticipated that there was a small body of research available; therefore a sensitive search strategy for clinical effectiveness studies was undertaken to retrieve all information, which might be useful on ozone therapy for dental caries. Additional searches were carried out for economic data and these are detailed in Chapter 4 of the systematic review companion document. In addition, selected conferences proceedings that were not available electronically were handsearched. These were International Association for Dental Research (IADR) conference proceedings for 1999-2001 and the annual European Organization for Caries Research (ORCA) Congresses 2000-2003. Research abstracts, published on industry and users Web sites (KaVo Dental Ltd., CurOzone USA Inc., HealOzone, and DentalOzone; see Appendix 1 of the systematic review companion document for full details), were also identified. Reference lists of included studies were also checked for additional study reports.
Inclusion and Exclusion Criteria
All citations identified by the search strategy were assessed for relevance by two reviewers. Copies of the full-text, published papers of those considered to be relevant were then obtained. It was decided that studies reported in languages other than English would be identified but not included in the review. For clinical effectiveness assessment, included studies were randomised controlled trials (RCTs) of ozone treatment (HealOzone) versus at least one comparator (nil, placebo, or active treatment). Data from studies other than randomised trials were collected but not included in the review. The outcome measures were required to be measures of clinical effectiveness (e.g., reversal/progression of caries). Only in-vivo studies involving human subjects were deemed to be suitable for inclusion whilst studies reporting in-vitro results were excluded. Studies were also excluded if their follow-up was less than six months or did not report clinically relevant outcome measures.
Data Extraction Strategy
A data abstraction form was designed (see Appendix 2 of the systematic review companion document) to collect details from each individual study. This included the type of study design, number of participants and their characteristics, intervention characteristics, caries information including location and severity of lesion, and patient outcomes such as reversal of caries, progression of caries, and any reported adverse events. In particular, the outcomes sought for the included studies were as follows:
- Non-cavitated caries
- Reversal of caries
- Progression of caries
- Utilisation of dental services (e.g., visits to dental care units; duration of dental treatment)
- Adverse events
- Patient centred measures (e.g., patient satisfaction and preference, relief of pain/discomfort)
- Quality of life
- Cavitated caries
- Time to restorative interventions
- Need for further restorative interventions and length of time between restorations
- Symptoms of pulpal pathology
Inclusion criteria were assessed independently by two reviewers. Any disagreements were resolved by consensus or referred to a third reviewer. Reviewers were not blinded to the names of study authors, institutions, or publications.
Quality Assessment Strategy
Two reviewers assessed the methodological quality of all included studies and any disagreements were resolved by discussion. The quality assessment of randomised controlled trials was formally assessed using a published checklist modified by the reviewers for the purpose of this review. The checklist consists of 12 questions, which focus on the following methodological aspects: method of randomisation, unit of randomisation, concealment of allocation, comparability of groups at baseline, blinding procedures, number of withdrawals/dropouts, and completeness of assessment at follow-up.
For each question a 'Yes', 'No' or 'Unclear' answer is required. The quality assessment checklist is presented in Appendix 3 of the systematic review companion document.