Background: The traditional approach of carious lesions with risk for progression has has been to excavate all infected and demineralised tissue before placement of the restoration. In primary teeth, treatment of deep carious lesions is associated with significant risk of pulp lesions and postoperative complications and thus the risk of the teeth being lost. During the past decade, more focus has been on biological methods for caries excavating of deep dentin lesions. An overview comparing different biological methods such as partial or stepwise excavation of deep dentin caries in primary teeth shows that they work as well as traditional methods performing complete caries excavation but have the benefits of reducing the risk of iatrogenic pulp damage [1-3].

Our primary hypothesis is that there is no difference in tooth or filling survival after partial caries excavation compared to complete caries excavation in primary molars.

The secondary hypothesis is that the therapist's knowledge, experience and treatment attitudes and choices are not affected by a participation in the study.

The treatment of carious lesions with risk for progression has traditionally been done with caries removal and restorative treatment of the affected teeth. In primary teeth, different treatments for deep carious lesions have been described. Complete excavation aims to removing all infected and demineralised dentin with a high risk of pulpal exposure, postoperative complications and thus the risk of the teeth being lost. In many cases, treatment also involves pain and suffering for the patient, which can lead to dental fear among children.

In latest years there has been a growing evidence for the possibility of controlling the cariogenic biofilm in the lesion by isolating the infected tissue from the oral cavity with an isolating restoration and leaving infected tissue under the permanent restoration. The methods are considered to be able to slow down or arrest the caries progression in primary teeth so that the teeth exfoliate without causing pain or infection. When carious tissue is isolated from the oral environment deprives the residual bacteria from carbohydrates and has thus been shown to have an antibacterial effect and to stop further progression of the lesion [4-5]. Partial, i.e. one-step incomplete or selective excavation is one biological method that seals carious dentin under a definitive restoration, omitting any re-entry. This can thus be a treatment choice for the primary teeth.

An overview comparing different biological methods for caries excavation of deep dentin caries in primary teeth, such as partial or stepwise excavation shows that they work as well as traditional methods performing complete caries excavation but have the benefits of reducing the risk of iatrogenic pulp damage [1-4]. However, partial excavation compared with complete excavation in deep carious lesions in primary teeth has not previously been tested under practice-like conditions. If the study shows that the treatment is effective in clinical practice and in the hands of multiple operators, it will change the routine treatment of dentin caries in primary teeth, thus increasing the survival of teeth and fillings, as well as reducing the risk of unwanted injury to the pulp and pain and discomfort to the children.

Objectives and Hypothesis: The primary purpose of the study is to investigate the sustainability of filling and the tooth survival after two different methods of excavation of dentin caries in primary molars.

The primary hypothesis is that there is no difference in tooth or filling survival after partial caries excavation compared to complete caries excavation in primary molars.

The secondary purpose of the study is to investigate the therapist's knowledge, experience and treatment attitude and choice of treatment method in primary caries excavation and how a participation in the study affects the therapist.

The secondary hypothesis is that the therapist's knowledge, experience and treatment attitudes and choices are not affected by a participation in the study.

The study aims to testing a newly started Practice-Based Research Network (PBRN) within the discipline of pediatric dentistry in the Stockholm city county in Sweden and the county of Östergötland. Thus, the scientific question will be tested under an effectiveness setting including practitioners interested in participating in the PBRN by signing up for participating in this particular study. The study has a prospective multi-center, two arms randomized controlled clinical trial design.

Inclusion Criteria:

• Children in the age of 3-8 years, with one or more primary molar teeth in a need of a restoration due to a moderate depth of carious lesion;

  • caries lesion diagnosed into dentin on radiographs though not exceeding the inner third of the dentin
  • caries lesion diagnosed visually with a cavity into dentin.

Exclusion Criteria:

• Children with behaviour management problems.
• Teeth with pulpal symptoms
• Teeth expected to exfoliate within the next 18 months