Dentists in NHS practices across the UK will test whether leaving some soft decay in a tooth, rather than drilling it all out, keeps the tooth alive longer. This matters because standard practice for deep cavities is to remove all decayed dentine, but that risks exposing the pulp and damaging the nerve, often leading to root canal treatment or extraction. The alternative—selective caries removal—leaves soft dentine near the pulp and seals the tooth with a filling. The trial directly compares the two approaches in permanent back teeth, asking which better preserves tooth vitality and reduces pain, re-treatment, and cost to both patients and the NHS. If selective removal proves more effective, it could change routine dental care across the UK. Patients would keep more of their natural teeth, avoid invasive procedures, and the NHS could reduce spending on root canals, crowns, and extractions. The trial also tracks quality of life and willingness to pay, giving policymakers clear evidence on whether to update clinical guidelines.
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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. Setting Sixty-five primary dental care practices recruited from the UK. Population Patients with deep carious lesions who are seeking healthcare at NHS general dental practices. Inclusion criteria • Aged 12 and over, suitable to receive either clinical procedure in the trial. • One (or more) pre-molar or molar teeth with caries (primary or secondary) extending into the pulpal third of dentine. • Lesion affecting proximal and/or occlusal surfaces and would be filled with a single direct restoration. • Able to give own consent • Receive some or all of their treatment under the NHS Exclusion criteria • If the carious tooth shows signs or symptoms of irreversible pulp pathology or loss of vitality Intervention 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. Control 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.”. Primary outcome Clinical: sustained tooth vitality at 38 months median follow up Secondary outcomes Clinical:pulp exposure during caries removal; progression of caries; tooth-restoration failure and re-restoration Patient-centred: dental pain; need for dental pain relief; health status; oral health-related quality of life Economic: NHS and patient perspective costs;general population preferences;willingness to pay;incremental net benefits;QALYs and incremental cost per QALY. Sample size 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. Project timetable 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). Expertise in team 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
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