Cochrane on dental recall intervals (2020): for adults, six-month, risk-based and 24-month check-ups came out the same over four years

What it says#

The review, published by Cochrane Oral Health on October 14, 2020, asks one question: what is the optimal recall interval of dental check-up for oral health in a primary care setting. The authors searched to January 17, 2020 with no restriction on language or date, included only randomized controlled trials of different recall intervals in primary care, and rated the certainty of every result with GRADE. Their background paragraph names the tradition under test: six-month check-ups have traditionally been advocated by general dental practitioners in many high-income countries, while recommendations vary between countries and dental healthcare systems.

Two trials met the criteria, with data from 1736 participants. One was run in a public dental service clinic in Norway in regular attenders under 20 years of age; it compared 12-month with 24-month recall and measured outcomes at two years. The other was run in UK general dental practices, 51 of them according to the plain language summary, in adults who were regular attenders, defined as having attended the dentist at least once in the previous two years. It compared six-month, 24-month and risk-based recall, where the dentist set the interval from the individual's risk of dental disease, and measured outcomes at four years. The outcomes the review counted were dental caries, gingival bleeding and oral-health-related quality of life. Neither trial measured other potential adverse effects.

Risk-based versus six-month recall in adults at four years: high-certainty evidence of little to no difference in the number of tooth surfaces with any caries (ICDAS 1 to 6; MD 0.15, 95% CI -0.77 to 1.08; 1478 participants), the proportion of sites with gingival bleeding (MD 0.78%, 95% CI -1.17% to 2.73%; 1472 participants) and oral-health-related quality of life (MD in OHIP-14 scores -0.35, 95% CI -1.02 to 0.32; 1551 participants). There is probably little to no difference in the prevalence of moderate to extensive caries (ICDAS 3 to 6; RR 1.04, 95% CI 0.99 to 1.09; 1478 participants; moderate certainty).

24-month versus six-month recall in adults at four years: moderate-certainty evidence that there is probably little to no difference in tooth surfaces with any caries (MD -0.60, 95% CI -2.54 to 1.34; 271 participants) and in gingival bleeding (MD -0.91%, 95% CI -5.02% to 3.20%; 271 participants); there may be little to no difference in moderate to extensive caries (RR 1.05, 95% CI 0.92 to 1.20; 271 participants; low certainty); and high-certainty evidence of little to no difference in quality of life (OHIP-14 MD -0.24, 95% CI -1.55 to 1.07; 305 participants).

Risk-based versus 24-month recall in adults at four years: probably little to no difference in moderate to extensive caries (RR 1.06, 95% CI 0.95 to 1.19; 279 participants) and in tooth surfaces with any caries (MD 1.40, 95% CI -0.69 to 3.49; 279 participants), both moderate certainty; high-certainty evidence of no important difference in gingival bleeding (MD -0.07%, 95% CI -4.10% to 3.96%; 279 participants) or quality of life (OHIP-14 MD -0.37, 95% CI -1.69 to 0.95; 298 participants).

Children and adolescents, 24-month versus 12-month recall at two years: the certainty is very low, so it is unclear whether caries experience differs. For 3- to 5-year-olds with primary teeth the mean difference in dmfs increment was 0.90 (95% CI -0.16 to 1.96; 58 participants); for 16- to 20-year-olds with permanent teeth the MD in DMFS increment was 0.86 (95% CI -0.03 to 1.75; 127 participants). The plain language summary attributes the uncertainty to problems with the way that study was conducted.

The plain language summary states the conclusion for a patient: whether adults see their dentist for a check-up every six months or at personalized intervals based on their dentist's assessment of their risk of dental disease does not affect tooth decay, gum disease or quality of life, and longer intervals, up to 24 months, may not negatively affect these outcomes. For children and adolescents there is not enough reliable evidence to say how often they should be seen.

Who it applies to#

The strong findings are about adults who already come in regularly, seen in general practice, followed for four years. That is most of an established hygiene schedule. The risk-based arm is worth reading precisely: the interval was set by the dentist from the individual's risk of dental disease, which is a documented clinical judgment, not a fixed number.

Three groups sit outside the evidence. Patients who do not attend regularly were not enrolled, so nothing here describes what a two-year gap does to someone who was already behind. Children and adolescents are covered by one small trial at very low certainty, and the authors say plainly that the evidence is uncertain. And the review compares intervals only; it does not test what is done at the visit, and it reports that neither trial assessed adverse effects of the strategies.

What changed#

The 2013 version of this review (Riley and colleagues, CD004346.pub4) contained one trial of 185 participants, the Norwegian study, rated as very low quality evidence, and concluded that there was no evidence to support or refute the practice of encouraging patients to attend for dental check-ups at six-monthly intervals. Its objectives also tried to separate types of check-up (examination alone, with scale and polish, with preventive advice), none of which had trial evidence.

The 2020 update added the UK adult trial, which supplies almost all of the 1736 participants and every high-certainty result. That moved the adult question from "no evidence either way" to "little to no difference" between six-month and risk-based recall, with 24-month recall probably no different, across caries, bleeding and quality of life at four years. The conclusion for children did not move.

Where the source is#

The document is Fee and colleagues, Recall intervals for oral health in primary care patients, Cochrane Database of Systematic Reviews 2020, issue 10, CD004346.pub5, published by Cochrane Oral Health; the link under the title opens the Cochrane Library page with the abstract and plain language summary. The same text is free in PubMed Central (PMC8256238) and the abstract is on PubMed. When this entry was written the Cochrane Library refused automated access, so the abstract was read from PubMed and the plain language summary from PubMed Central; the 2013 version was read from its PubMed record. The review's full data tables are behind Cochrane Library access in some countries.