Pulp treatment for extensive decay in primary teeth

Review question

The main question addressed by this review is how effective are different options for treating extensive tooth decay in children's milk teeth to resolve the child's symptoms (typically pain, swelling, abnormal movement) and tooth signs (as shown on an x-ray).

Background

Tooth decay in the milk teeth (or primary teeth) of children tends to progress rapidly, often reaching the dental nerve (or pulp (the nerves, tiny blood vessels and connective tissue that make up the centre of a tooth)). Thus, dentists often have to perform one of three pulp treatment techniques: direct pulp capping (where a medicament is placed directly over the exposed pulp), pulpotomy (removal of a portion of the pulp) or pulpectomy (removal of all of the pulp in the pulp chamber and root canal of a tooth). With direct pulp capping and pulpotomy, some of the nerve in the tooth is left and therefore a material has to be put into contact with this 'living' pulp tissue. The most common materials used for direct pulp capping are calcium hydroxide, the more recent but more expensive mineral trioxide aggregate, formocresol or an adhesive that allows adhesion of the restoration to the tooth (placed directly over the tooth's nerve). After a pulpectomy, no nerve is left inside the treated tooth, but a material has to be put in the space created by pulp removal and this material should not prevent the resorption of the primary tooth's root, to allow proper evolution of the permanent tooth. After a pulpotomy, one of four materials is generally used: ferric sulphate, formocresol, calcium hydroxide or mineral trioxide aggregate.

Study characteristics

The Cochrane Oral Health Group carried out this review of existing studies. The evidence is current up to October 2013.

We found 47 trials that investigated the success of dental nerve treatment (pulp treatment) of 3910 milk teeth. The trials were published between 1989 and 2012 and made 52 comparisons of different treatment options.

Key results

Due to the limited number of trials making each comparison, no clear treatment options were shown to be better than others for the treatment of extensive tooth decay in children's milk teeth.

Quality of the evidence

The quality of the evidence identified was low due to shortcomings in the methods used within the individual trials, the small number of children included in the trials and their short-term follow-up following treatment.

For direct pulp capping, the best material to apply on the tooth's nerve could not be identified because of too few studies including too few children. After a pulpotomy, mineral trioxide aggregate may be the material yielding the best treatment success; however, the evidence is limited by shortcomings in the quality of trials and short-term follow-up of children after treatment. After a pulpectomy, Vitapex (calcium hydroxide/iodoform) paste may yield better results than zinc oxide and eugenol pastes.

More studies are needed to confirm these results.

Authors' conclusions: 

We found no evidence to identify one superior pulpotomy medicament and technique clearly. Two medicaments may be preferable: MTA or FS. The cost of MTA may preclude its clinical use and therefore FS could be used in such situations. Regarding other comparisons for pulpectomies or direct pulp capping, the small numbers of studies undertaking the same comparison limits any interpretation.

Read the full abstract...
Background: 

In children, dental caries is among the most prevalent chronic diseases worldwide. Pulp interventions are indicated for extensive tooth decay. Depending on the severity of the disease, three pulp treatment techniques are available: direct pulp capping, pulpotomy and pulpectomy. After treatment, the cavity is filled with a medicament.

This is an update of a Cochrane review first published in 2003. The previous review found insufficient evidence regarding the relative efficacy of these interventions, combining one pulp treatment technique and one medicament.

Objectives: 

To assess the effects of different pulp treatment techniques and associated medicaments for the treatment of extensive decay in primary teeth.

Search strategy: 

We searched the Cochrane Oral Health Group's Trials Register (to 25 October 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 9), MEDLINE via OVID (1946 to 25 October 2013), EMBASE via OVID (1980 to 25 October 2013) and the Web of Science (1945 to 25 October 2013). We searched OpenGrey for grey literature and the US National Institutes of Health Trials Register and the World Health Organization (WHO) Clinical Trials Registry Platform for ongoing trials. We placed no restrictions on the language or date of publication when searching the electronic databases.

Selection criteria: 

Eligible studies were randomised controlled trials comparing different pulp interventions combining a pulp treatment technique and a medicament in children with extensive decay involving dental pulp in primary teeth.

Data collection and analysis: 

Two review authors independently carried out data extraction and risk of bias assessment in duplicate. We contacted authors of randomised controlled trials for additional information if necessary. The primary outcomes were clinical failure and radiological failure, as defined in trials, at six, 12 and 24 months. We performed data synthesis with pairwise meta-analyses using fixed-effect models. We assessed statistical heterogeneity using by I2 coefficients.

Main results: 

We included 47 trials (3910 randomised teeth) compared to three trials in the previous version of the review published in 2003. All trials were single centre and small sized (median number of randomised teeth 68). Overall, the risk of bias was low in only one trial with all other trials being at unclear or high risk of bias. The overall quality of the evidence was low. The 47 trials examined 53 different comparisons: 25 comparisons between different medicaments/techniques for pulpotomy, 13 comparisons between different medicaments for pulpectomy, 13 comparisons between different medicaments for direct pulp capping and two comparisons between pulpotomy and pulpectomy. Regarding pulpotomy, 14 trials compared mineral trioxide aggregate (MTA) with formocresol (FC). MTA reduced both clinical and radiological failures at six, 12 and 24 months, although the difference was not statistically significant. MTA also showed favourable results for all secondary outcomes measured, although again, differences between MTA and FC were not statistically significant (with the exception of pathological root resorption at 24 months and dentine bridge formation at six months). MTA showed favourable results compared with calcium hydroxide (CH) (two trials) for all outcomes measured, but the differences were not statistically significant (with the exception of radiological failure at 12 months). When comparing MTA with ferric sulphate (FS) (three trials), MTA had statistically significantly fewer clinical, radiological and overall failures at 24 months. This difference was not shown at six or 12 months.

FC was compared with CH in seven trials and with FS in seven trials. There was a statistically significant difference in favour of FC for clinical failure at six and 12 months, and radiological failure at six, 12 and 24 months. FC also showed favourable results for all secondary outcomes measured, although differences between FC and CH were not consistently statistically significant across time points. The comparisons between FC and FS showed no statistically significantly difference between the two medicaments for any outcome at any time point.

For all other comparisons of medicaments used during pulpotomies, pulpectomies or direct pulp capping, the small numbers of studies and the inconsistency in results limits any interpretation.

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