Aim: To devise measurement instruments for 'quality' of root canal treatment to assess training and outcome of general dental practitioners working within primary care settings.Method: Scoring systems relating to quality of root canal treatment were developed using expert consensus and published literature. Domains scored included the Treatment Process, Quality of the Obturation, Clinical Healing, Radiographic Healing and Tooth Complexity.Scoring systems were applied to 10 clinical cases treated by each dentist at the beginning and 10 cases treated at the end of their clinical training and 135 cases treated after completion of training. The dentists recorded the treatment process and clinical healing in clinical logs. Two examiners independently scored the radiographs after undertaking calibration and training. Inter-and intra-examiner reliability of scoring radiographic outcomes was tested.Results: Instrument created with 4 domains to assess quality (2 process and 2 outcome), and a measure of case complexity (structure). One domain of process (n=240 teeth), one domain of outcome (n=32 teeth) and the complexity (n=215 teeth) were scored using radiographs. The Kappa scores for intra-examiner reliability between 0.22 and 1, whilst interexaminer reliability ranged between 0.18 and 0.99. Conclusion: Evidence based scores for assessment of the quality (process and outcome) and complexity (structure) of root canal treatment were devised. They are reliable, provided that clinicians are trained in record keeping and examiners have in depth training and calibration in the use of the instruments.