Lower first permanent molars: developing better predictors of spontaneous space closure.

BACKGROUND: First, first permanent molars (FPMs) of poor prognosis are often planned for extraction at an 'ideal time' so that second permanent molars (SPMs) erupt favourably to replace them. However for lower FPM extractions, timing is not an accurate predictor of success. OBJECTIVE: The aim of this study was to identify additional radiographic factors that could better predict the degree of spontaneous space closure of the lower SPM following FPM extraction. METHODS: Data from a previous study of 127 lower SPMs from 66 patients was re-analysed by incorporating additional radiographic factors. These included calcification stage of the bifurcation of the SPM, position of the second premolar, mesial angulation of SPM in relation to the FPM, and presence of the third permanent molar. Results were analysed using ordered logistic regression. RESULTS: Only 58 per cent of FPMs extracted at the 'ideal time' (SPM development at Demirjian stage E) had complete space closure. The best outcomes resulted from a combination of SPMs not at Demirjian development stage G, together with the presence of mesial angulation of the SPM and presence of the third permanent molar, where 85 per cent of those cases had complete space closure. CONCLUSIONS: Apart from extraction timing of the FPM, consideration must also be given to the presence of the third permanent molar and angulation of the SPM in order to ensure a reliable degree of spontaneous space closure of the lower SPM.

An in vivo and in vitro investigation of the use of ICDAS, DIAGNOdent pen and CarieScan PRO for the detection and assessment of occlusal caries in primary molar teeth.

OBJECTIVES: The aim of this study was to investigate the in vivo and in vitro validity of International Caries Detection and Assessment System (ICDAS), DIAGNOdent pen and CarieScan PRO in the detection and assessment of occlusal caries in primary teeth. METHODS: Sixty-four molars were assessed using all three systems under standardised in vivo conditions. They were then extracted and assessed by two examiners in vitro along with an additional 38 teeth (102 teeth in total from 45 children). Downer's histological scoring criterion was the validation gold standard. Sensitivity, specificity, positive and negative likelihood ratios and area under the receiver-operator curves were calculated for all caries and dentine caries. Repeatability was analysed using Cohen's Kappa and the performance of the systems between in vivo and in vitro settings by the same examiner were compared. RESULTS: ICDAS showed the highest validity and repeatability. The DIAGNOdent pen's overall clinical validity was comparable to that of ICDAS, but it demonstrated only moderate repeatability. CarieScan PRO had negligible validity in vivo, and there was no relationship between in vivo and in vitro parameters. CONCLUSIONS: The in vivo results of ICDAS and DIAGNOdent pen were satisfactory and comparable to those obtained in vitro, with ICDAS performing better. The CarieScan PRO performed poorly under both conditions. CLINICAL RELEVANCE: ICDAS should be the index of choice when detecting and assessing occlusal caries in the primary dentition, and in vitro data can be safely extrapolated in vivo. The DIAGNOdent pen must be employed with caution. Currently, the CarieScan PRO is unsuitable for use in the primary dentition.