Data sources

Trials were sourced using the Cochrane Oral Health Group Trials Register, the Cochrane Central Register of Controlled Trials, Medline and Embase. Reference lists from relevant articles were scanned and the authors of some papers were contacted to identify further trials and obtain additional information.

Study selection

Trials were selected if they met the following criteria:

design: random allocation of participants;

participants: all children and adults receiving dental check-ups in primary-care settings, irrespective of their level of risk for oral disease;

interventions: recall intervals for either clinical examination only, clinical examination plus scale and polish, clinical examination plus preventive advice, clinical examination plus scale and polish plus preventive advice, no recall interval/patient-driven attendance (which may be symptomatic), or clinician risk-based recall intervals;

outcomes: clinical status outcomes for dental caries including, but not limited to, mean dmft/DMFT, dmfs/DMFS scores, caries increment, filled teeth (including replacement restorations), early carious lesions (arrested or reversed); periodontal disease (including, but not limited to, plaque, calculus, gingivitis, periodontitis, change in probing depth, and attachment level); oral mucosa (presence or absence of mucosal lesions, potentially malignant lesions, cancerous lesions, and size and stage of cancerous lesions at diagnosis).

In addition, the following outcomes were considered where reported: patient-centred outcomes, economic-cost outcomes, other outcomes such as improvements in oral health knowledge and attitudes, harms, changes in dietary habits, and any other oral health-related behavioural change.

Data extraction and synthesis

Information regarding methods, participants, interventions, outcome measures, and results were independently extracted, in duplicate, by two authors. Authors were contacted, where deemed necessary and where possible, for further details regarding study design and for data clarification. A quality assessment of the included trial was carried out. The Cochrane Oral Health Group's statistical guidelines were followed.

Results

Only one study (with 188 participants) was included in this review and was assessed as having a high risk of bias. This study provided limited data for dental caries outcomes (dmfs/DMFS increment) and economic cost outcomes (reported time taken to provide examinations and treatment).

Conclusions

There is insufficient evidence from randomised controlled trials (RCT) to draw any conclusions regarding the potential beneficial and harmful effects of altering the recall interval between dental check-ups. There is insufficient evidence to support or refute the practice of encouraging patients to attend for dental check-ups at 6-monthly intervals. It is important that high quality RCT are conducted for the outcomes listed in this review in order to address its objectives.