Qualitative and quantitative determination of dental amalgam restoration volume.
BACKGROUND
Volume of tooth structure replaced by an existing restoration, as assessed by visual and radiographic examination, is one diagnostic measure used by dental practitioners and dental insurance agencies to determine the relative need to restore a tooth with a full-coverage cast restoration. However, use of these methods has not been validated.


OBJECTIVE
This study compared the volume of a range of dental amalgam restorations placed in typodont teeth, as estimated by dentists, dental students and laypersons, with the actual volume of each restoration.


METHODS
Sixty subjects (20 dental school faculty, 20 dental students, and 20 clerical staff [laypersons]) participated. After reviewing photographic images of typodont teeth with mesial-occlusal-distal dental amalgam restorations, subjects estimated the volume of each restoration using various restorations on different teeth as a percentage of its tooth's coronal volume. The actual volume of each dental amalgam restoration and that of the coronal portion of the prepared teeth was calculated with a volumetric displacement technique. The single sample 2-sided t test with a.05 level of significance was used to evaluate the null hypothesis (H0 ): The survey participant's estimates of each restoration's percentage volume are the same as the measured volume values versus the alternative hypothesis (H1 ): estimates differed from the measured volume values. One-way analysis of variance was used to determine the significance of any difference between the estimates of the 3 survey test groups.


RESULTS
Average volumes reported by all 3 groups were significantly different than the measured volume values (P <.05). Experience and dental training did not significantly affect a participant's ability to evaluate restoration volumes with greater accuracy. Results reported by dentists, dental students, and laypersons were not significantly different (P >.05).


CONCLUSIONS
The volume of a restoration is inaccurately assessed by visual and radiographic examination.
Covey
D A
DA
College of Dentistry, University of Nebraska Medical Center, Lincoln 68583-0750, USA. Dcovey@unmc.edu
Kent
D K
DK
Dunning
D G
DG
Koka
S
S
D000704:Analysis of Variance; D001641:Bicuspid; D003723:Dental Amalgam / Q000627:therapeutic use*; D003737:Dental Cavity Preparation / Q000379:methods / Q000706:statistics & numerical data; D003793:Dental Restoration, Permanent / Q000379:methods* / Q000706:statistics & numerical data; D003815:Dentists / Q000706:statistics & numerical data; D019317:Evidence-Based Medicine; D006801:Humans; D008963:Molar; D015203:Reproducibility of Results; D013335:Students, Dental / Q000706:statistics & numerical data; D011795:Surveys and Questionnaires; D019228:Tooth Crown / Q000033:anatomy & histology*; D014093:Tooth, Artificial
D003723:Dental Amalgam