Highlighted review: Dental cavity liners under tooth‐colored resin fillings placed into permanent teeth in the back of the mouth

Andrew B Schenkel, Analia Veitz‐Keenan

Plain language summary: Dental cavity liners under tooth‐colored resin fillings placed into permanent teeth in the back of the mouth

Review question
This review was conducted to assess the effects of using liners under tooth‐colored resin fillings in cavities on the biting surface (Class I) and the biting surface and side(s) (Class II) of permanent teeth in the back of the mouth in children and adults.

Background
Tooth decay is the most common disease affecting children and adults worldwide. If left untreated, acid produced by bacteria in the dental plaque or biofilm forms cavities or holes in the teeth. A number of techniques and a variety of materials can be used to restore or fill teeth affected by decay. One of these materials is tooth‐colored, resin‐based composite or RBC. This material is increasingly used as an alternative to amalgam (a mixture of mercury and metal alloy particles).

Since the 19th century liners have often been placed in cavities in the teeth under the filling material. The liners are thought to protect the living pulp of the tooth from filling materials themselves and also from their potential to allow more heat or cold through than the natural tooth would. Although RBC filling materials are thought to be similar to the natural material of teeth in terms of how they conduct heat, sensitivity to temperature change is sometimes still an issue for people after treatment.

Study characteristics
The evidence in this review, carried out by authors from Cochrane Oral Health, is up to date as of 12 November 2018.

Eight studies, with over 700 participants, were included. Two studies were conducted in the USA, two in Thailand, two in Germany and one each in Saudi Arabia and Turkey. The studies compared the use of liners under tooth‐colored resin fillings (RBC) in permanent teeth at the back of the mouth to no liners for Class I and Class II fillings. One of the two studies in the USA took place in dental practices, the others in university‐based dental schools. All participants were over 15 years of age.

Key results
Very little evidence was found to show that a liner under Class I and II RBC fillings in permanent teeth in the back of the mouth reduced sensitivity in adults or children 15 years or older. No evidence was found to show that there was any difference in the length of time fillings lasted when placed with or without a cavity liner. No adverse events were reported in any of the included studies.

Quality of evidence
The body of evidence identified in this review does not allow for robust conclusions about the effects of dental cavity liners. The quality of the evidence identified in this review is low and there is a lack of confidence in the effect estimates. Furthermore, no evidence was found to demonstrate a difference in how long restorations last when placed with or without dental cavity liners.

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Citation: Schenkel  AB, Veitz‐Keenan  A. Dental cavity liners for Class I and Class II resin‐based composite restorations. Cochrane Database of Systematic Reviews 2019, Issue 3. Art. No.: CD010526. DOI: 10.1002/14651858.CD010526.pub3.