Laser Doppler flowmetry of restored molar teeth

Objectives: (i) To compare laser Doppler pulp blood flow (PBF) signals from restored and unrestored first molar teeth; (ii) to compare PBF in teeth with large and small restorations and (iii) to relate PBF to pulp dimensions on radiographs. Methods: Bitewing radiographs of young adults with restored first molars were digitally scanned and the pulps measured. Subjects were divided into 2 groups: group A having a restored tooth and a corresponding unrestored contralateral tooth (43 subjects); and group B, having a molar with a small (usually occlusal) restoration while the contralateral tooth featured either a much more extensive occlusal restoration or restored proximal surface(s) (30 subjects). The 146 teeth responded to electric pulp tests, and their PBF was recorded using a Moor Instruments MBF-3D blood flow meter. Data were analysed using Student's t - test. Results: In group A, the PBF in the restored teeth was not significantly different from the unrestored antimeres (P = 0.063); however, the pulp area in the clinical crowns was diminished (P = 0.028). The molars with large restorations in group B had significantly lower PBF than the contralaterals with smaller restorations (P = 0.004), and their total pulp area was reduced (P = 0.002). Conclusion: In first molars the pulp dimensions were influenced by the presence of restorations, but the PBF was only reduced in heavily restored teeth. Laser Doppler flowmetry can be considered an effective test of pulp vitality in restored posterior teeth.