Title: Selective Caries Removal in Permanent Teeth (SCRIPT)
Funder: Chief Scientist Office, Scotland

Abstract: HEALTH NEED: Tooth decay is very common with the majority of teenagers and adults having some decay in their back teeth. Treating tooth decay costs the NHS over £3.4 billion each year. There are different ways of treating decayed teeth where the decay has spread deep into the tooth close to the nerve. The most common way is to take away all of the decay before placing a filling in the tooth. This is known as “complete decay removal”. When removing all of the decay there is a small chance of serious damage to the nerve. Such damage makes root canal treatment or tooth loss (extraction) likely. Also drilling the tooth to remove all the decay can weaken the tooth so it is more likely to break and need further treatment._x000D_ _x000D_ WHY THIS STUDY IS NEEDED: Dentists want to compare the complete removal of decay with a new way that does not remove all of the decay. In the new way, some of the decay is left behind and sealed under the filling. This is known as “partial decay removal”. There is research in children’s teeth that supports this new way. However, there are gaps in our knowledge about partial decay removal in adult teeth._x000D_ _x000D_ AIM: SCRIPT will test “partial or selective decay removal” compared to “complete decay removal” to establish how long the tooth remains healthy (vital), if further follow-up treatment was needed, the costs incurred, the pain experienced by the patients and the impact on their lives._x000D_ _x000D_ DESIGN: We have designed a study where patients will be given one of the two treatments at random. We will do the trial in two stages. In the first we will check we can recruit a sufficient number of dentists and patients to generate enough data to draw meaningful conclusions and that what we are planning is acceptable to patients. If so, we will then go on to the second stage and do a large trial._x000D_ _x000D_ SETTING: We will recruit 65 dental practices in England and Scotland. The dentists will recruit a total of 623 NHS dental patients over 12 years old who have deep decay in a back adult tooth,who are suitable for either treatment, can give their own consent and who agree to take part._x000D_ _x000D_ OUTCOMES: We will measure how well the treatment works over three years. We will look for evidence of serious damage to the nerve of the tooth. We will measure if the tooth needs root canal treatment or the tooth is lost (extracted by dentist) because the tooth has died. We will also measure damage to the nerve during treatment, patients’ pain, the impact of the mouth on patient’s daily lives, survival of the filling, need for more treatment and costs._x000D_ _x000D_ METHOD: We will use questionnaire surveys of patients, X-rays and data from dentists to test the success of the two ways to treat deep decay. We will also interview dental staff and patients about their views on the two ways to treat deep decay._x000D_ _x000D_ PATIENT AND PUBLIC INVOLVEMENT: Many patients and members of the public have helped plan the study. They were keen we tested newer ways of treating tooth decay. They wanted us to look at pain, tooth loss, need for treatment and cost of treatment. The patients and public will continue to be involved as members of the study team and others will be external advisors to the study.

Lay abstract: SCRIPT is a pragmatic, primary dental care, multi-centre,two-arm patient randomised controlled trial including an internal pilot, comparing the clinical and cost-effectiveness of Selective Caries Removal with Complete Caries Removal in permanent posterior teeth. A mixed-method process evaluation will complement the outcome evaluation and examine implementation issues._x000D_ _x000D_ Setting_x000D_ Sixty-five primary dental care practices recruited from the UK. _x000D_ _x000D_ Population_x000D_ Patients with deep carious lesions who are seeking healthcare at NHS general dental practices. _x000D_ Inclusion criteria_x000D_ • Aged 12 and over, suitable to receive either clinical procedure in the trial._x000D_ • One (or more) pre-molar or molar teeth with caries (primary or secondary) extending into the pulpal third of dentine._x000D_ • Lesion affecting proximal and/or occlusal surfaces and would be filled with a single direct restoration._x000D_ • Able to give own consent_x000D_ • Receive some or all of their treatment under the NHS_x000D_ Exclusion criteria_x000D_ • If the carious tooth shows signs or symptoms of irreversible pulp pathology or loss of vitality_x000D_ _x000D_ Intervention_x000D_ Selective Caries Removal: caries removed to leave soft dentine, that is “dentine that deforms when a hard instrument is pressed into it and can be easily scooped up (e.g. with a spoon hand excavator) with little force being required”. The technique will be a one-stage clinical restorative procedure._x000D_ _x000D_ Control_x000D_ Complete caries removal: caries removal to firm dentine that is “physically resistant to hand excavation, and some pressure needs to be exerted through an instrument to lift it.”._x000D_ _x000D_ Primary outcome_x000D_ Clinical: sustained tooth vitality at 38 months median follow up _x000D_ _x000D_ Secondary outcomes _x000D_ Clinical:pulp exposure during caries removal; progression of caries; tooth-restoration failure and re-restoration_x000D_ Patient-centred: dental pain; need for dental pain relief; health status; oral health-related quality of life_x000D_ Economic: NHS and patient perspective costs;general population preferences;willingness to pay;incremental net benefits;QALYs and incremental cost per QALY. _x000D_ _x000D_ Sample size_x000D_ The sample size is events based; target difference of 9%; from 83% to 92% in sustained tooth vitality at 3 years. Recruitment of 623 participants (71 events) will detect a hazard ratio of 0.42 between experimental and control strategies and provide, using the log-rank test, 90% power at a 2-sided 5% significance level, assuming an exponential failure rate. The calculation assumes 17 months of recruitment, a minimum of 33 months of follow-up and a 30% follow-up attrition at the end of year three._x000D_ _x000D_ Project timetable_x000D_ Key milestones: Pre-trial preparation – regulatory approvals (Months -4 to 0); Recruitment and training of practices (Month 3 to 14); Recruitment of participants (Month 6 to 23); Assessment of internal pilot stop/go criteria (Month 12); Final follow-up of participants (Month 6 - 53); Write up and trial close-down (Month 57)._x000D_ _x000D_ Expertise in team_x000D_ Dental trialists with substantial experience of leading HTA dental trials; cariology & minimally invasive dentistry; cariology & paediatric dentistry; public health & routine data; lay member/PPI lead; general practitioners involved in research; health economics; behavioural science; qualitative research; statistics

Research activity codes: 6.4 SURGERY
Health categories: ORAL AND GASTROINTESTINAL