Recall intervals for oral health in primary care patients

BACKGROUND

The frequency with which patients should attend for a dental check-up and the potential effects on oral health of altering recall intervals between check-ups have been the subject of ongoing international debate for almost 3 decades. Although recommendations regarding optimal recall intervals vary between countries and dental healthcare systems, 6-monthly dental check-ups have traditionally been advocated by general dental practitioners in many developed countries.

OBJECTIVES

To determine the beneficial and harmful effects of different fixed recall intervals (for example 6 months versus 12 months) for the following different types of dental check-up: a) clinical examination only; b) clinical examination plus scale and polish; c) clinical examination plus preventive advice; d) clinical examination plus preventive advice plus scale and polish. To determine the relative beneficial and harmful effects between any of these different types of dental check-up at the same fixed recall interval. To compare the beneficial and harmful effects of recall intervals based on clinicians' assessment of patients' disease risk with fixed recall intervals. To compare the beneficial and harmful effects of no recall interval/patient driven attendance (which may be symptomatic) with fixed recall intervals.

SEARCH STRATEGY

We searched the Cochrane Oral Health Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), 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. Date of most recent searches: 9th April 2003.

SELECTION CRITERIA

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 the following different types of dental check-ups: a) clinical examination only; b) clinical examination plus scale and polish; c) clinical examination plus preventive advice; d) clinical examination plus scale and polish plus preventive advice; e) no recall interval/patient driven attendance (which may be symptomatic); f) 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, attachment level); oral mucosa (presence or absence of mucosal lesions, potentially malignant lesions, cancerous lesions, 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 COLLECTION AND ANALYSIS

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.

MAIN 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).

AUTHORS' CONCLUSIONS

There is insufficient evidence from randomised controlled trials (RCTs) 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 RCTs are conducted for the outcomes listed in this review in order to address the objectives of this review.

Routine scale and polish for periodontal health in adults

BACKGROUND

Many dentists or hygienists provide scaling and polishing for patients at regular intervals, even if those patients are considered to be at low risk of developing periodontal disease. There is debate over the clinical effectiveness and cost effectiveness of 'routine scaling and polishing' and the 'optimal' frequency at which it should be provided.

OBJECTIVES

The main objectives were: to determine the beneficial and harmful effects of routine scaling and polishing for periodontal health; to determine the beneficial and harmful effects of providing routine scaling and polishing at different time intervals on periodontal health; to compare the effects of routine scaling and polishing provided by a dentist or professionals complementary to dentistry (PCD) (dental therapist or dental hygienist) on periodontal health.

SEARCH STRATEGY

We searched the Cochrane Oral Health Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE. Reference lists from relevant articles were scanned and the authors of eligible studies were contacted where possible to identify trials and obtain additional information. Date of most recent searches: 9th April 2003.

SELECTION CRITERIA

Trials were selected if they met the following criteria: design - random allocation of participants; participants - anyone with an erupted permanent dentition who were judged to have received a 'routine scale and polish' (as defined in this review); interventions - 'routine scale and polish' (as defined in this review) and routine scale and polish provided at different time intervals ; outcomes- tooth loss, plaque, calculus, gingivitis, bleeding and periodontal indices, changes in probing depth, attachment change, patient-centred outcomes and economic outcomes.

DATA COLLECTION AND ANALYSIS

Information regarding methods, participants, interventions, outcome measures and results were independently extracted, in duplicate, by two reviewers. Authors were contacted where possible and where deemed necessary for further details regarding study design and for data clarification. A quality assessment of all included trials was carried out. The Cochrane Collaboration's statistical guidelines were followed and both standardised mean differences and weighted mean differences were calculated as appropriate using random-effects models.

MAIN RESULTS

Eight studies were included in this review and all studies were assessed as having a high risk of bias. Two split-mouth studies provided data for the comparison between scale and polish versus no scale and polish. One study, involving patients attending a recall programme following periodontal treatment, found no statistically significant differences for plaque, gingivitis and attachment loss between experimental and control units at each time point during the 1 year trial. The other study, involving adolescents in a developing country with high existing levels of calculus who had not received any dental treatment for at least 5 years, reported statistically significant differences in calculus and gingivitis (bleeding) scores between treatment and control units at 6, 12 and 22 months (in favour of 'scale and polish units') following a single scale and polish provided at baseline to treatment units. For comparisons between routine scale and polish provided at different time intervals, there were some statistically significant differences in favour of scaling and polishing provided at more frequent intervals: 2 weeks versus 6 months, 2 weeks versus 12 months (for the outcomes plaque, gingivitis, pocket depth and attachment change); 3 months versus 12 months (for the outcomes plaque, calculus and gingivitis). There were no studies comparing the effects of scaling and polishing provided by dentists or Professionals Complementary to Dentistry.

AUTHORS' CONCLUSIONS

The research evidence is of insufficient quality to reach any conclusions regarding the beneficial and adverse effects of routine scaling and polishing for periodontal health and regarding the effects of providing this intervention at different time intervals. High quality clinical trials are required to address the basic questions posed in this review.

Multiple effects of artemin on sympathetic neurone generation, survival and growth

To define the role of artemin in sympathetic neurone development, we have studied the effect of artemin on the generation, survival and growth of sympathetic neurones in low-density dissociated cultures of mouse cervical and thoracic paravertebral sympathetic ganglia at stages throughout embryonic and postnatal development. Artemin promoted the proliferation of sympathetic neuroblasts and increased the generation of new neurones in cultures established from E12 to E14 ganglia. Artemin also exerted a transient survival-promoting action on newly generated neurones during these early stages of development. Between E16 and P8, artemin exerted no effect on survival, but by P12, as sympathetic neurones begin to acquire neurotrophic factor independent survival, artemin once again enhanced survival, and by P20 it promoted survival as effectively as nerve growth factor (NGF). During this late period of development, artemin also enhanced the growth of neurites from cultured neurones more effectively than NGF. Confirming the physiological relevance of the mitogenic action of artemin on cultured neuroblasts, there was a marked reduction in the rate of neuroblast proliferation in the sympathetic ganglia of mice lacking the GFRα3 subunit of the artemin receptor. These results indicate that artemin exerts several distinct effects on the generation, survival and growth of sympathetic neurones at different stages of development.

In vivo survival requirement of a subset of nodose ganglion neurons for nerve growth factor

The sensory neurons of the nodose ganglion are the classic example of a population of peripheral nervous system neurons that do not require nerve growth factor (NGF) for survival during development but are dependent on other neurotrophins. We have re-examined this assertion by studying the development of the nodose ganglion of mice that have a null mutation in the NGF gene. Compared with wild-type embryos, the number of neurons undergoing apoptosis was elevated in NGF -/- mice, resulting in a significant reduction in the total number of neurons in the ganglion by the end of embryonic development. TrkA, the NGF receptor tyrosine kinase, was expressed in the nodose ganglion throughout development and there was a marked decrease in TrkA mRNA expression in the nodose ganglion of NGF -/- embryos. Although the in vitro survival of the majority of nodose neurons was promoted by brain-derived neurotrophic factor (BDNF), a minor proportion was supported by NGF in cultures established over a range of embryonic stages. These results clearly demonstrate that a subset of nodose ganglion neurons depends on NGF for survival during development. The finding that the expression of tyrosine hydroxylase (TH) mRNA was unaffected in the nodose ganglia of NGF-deficient embryos indicates that this NGF-dependent subset is distinct from the subset of catacholaminergic neurons in the nodose ganglion.

Differences and developmental changes in the responsiveness of PNS neurons to GDNF and neurturin

We have studied the ability of GDNF and neurturin to promote the in vitro survival of populations of embryonic chicken parasympathetic, sympathetic, and sensory neurons. We show that these neurons are more responsive to one or other of these factors at particular stages of development. Whereas the parasympathetic neurons are more sensitive to neurturin at late embryonic stages, sympathetic neurons are more sensitive to neurturin at early stages. In contrast, sensory neurons of the nodose ganglion are more sensitive to GDNF throughout embryonic development. Using competitive RT/PCR, we measured the levels of mRNAs encoding GDNF and neurturin receptors in purified neurons. All neurons expressed Ret mRNA, which encodes the common receptor tyrosine kinase for GDNF and neurturin. Neurons that were more sensitive to GDNF expressed higher levels of GFRalpha-1 mRNA than GFRalpha-2 mRNA and neurons that were more sensitive to neurturin expressed higher levels of GFRalpha-2 mRNA than GFRalpha-1 mRNA. These results show that populations of PNS neurons differ markedly in their responsiveness to GDNF and neurturin at certain stages of the development and suggest that these differences are governed in part by the relative levels of expression of members of the GFRalpha family of GPI-linked receptors.

GFRalpha1 is an essential receptor component for GDNF in the developing nervous system and kidney

Glial cell line-derived neurotrophic factor (GDNF) is a distant member of the TGFbeta protein family that is essential for neuronal survival and renal morphogenesis. We show that mice who are deficient in the glycosyl-phosphatidyl inositol (GPI) -linked protein GFRalpha1 (GDNFRalpha) display deficits in the kidneys, the enteric nervous system, and spinal motor and sensory neurons that are strikingly similar to those of the GDNF- and Ret-deficient mice. GFRalpha1-deficient dopaminergic and nodose sensory ganglia neurons no longer respond to GDNF or to the structurally related protein neurturin (NTN) but can be rescued when exposed to GDNF or neurturin in the presence of soluble GFRalpha1. In contrast, GFRalpha1-deficient submandibular parasympathetic neurons retain normal response to these two factors. Taken together with the available genetic and biochemical data, these findings support the idea that GFRalpha1 and the transmembrane tyrosine kinase Ret are both necessary receptor components for GDNF in the developing kidney and nervous system, and that GDNF and neurturin can mediate some of their activities through a second receptor.