Effect of restorations on pulpal blood flow in molars measured by laser Doppler flowmetry

To: (i) compare laser Doppler pulpal blood flow (PBF) signals from restored and unrestored first molar teeth, (ii) investigate PBF in teeth with large and small restorations, and (iii) to relate PBF to pulp chamber dimensions on radiographs.

Bitewing radiographs of young adults with restored first molars were obtained and pulp chamber dimensions measured. Subjects were divided into 2 groups: group A with a restored tooth and an unrestored contralateral (43 subjects) and group B, those with a molar with a small (usually occlusal) restoration whilst the contralateral tooth had an extensive occlusal restoration (or restorations) or restored proximal surface(s) and/or cuspal overlay (31 subjects). The 148 teeth responded to electric pulp testing, and their PBF was recorded using a laser Doppler flowmeter. Data were analysed using Student's t-test.

In group A the PBF in the restored teeth was significantly lower than in unrestored contralaterals (P = 0.028) and the total pulp chamber area and that in the clinical crown were smaller (P = 0.039 and 0.021 respectively). The group B molars with large restorations had significantly lower PBF than contralaterals with small restorations (P = 0.001), and their total pulp chamber area and pulp chamber width at cervix were reduced significantly (P = 0.003 and 0.032 respectively).

In molars the size of the pulp chamber was influenced by the presence of restorations and the PBF was reduced when restorations were present. Size and extent of restorations had a significant effect on PBF.