Objective: Dentists in The Dental Practice-Based Research Network (DPBRN) participated in a study regarding reasons for placement of the first restoration on permanent tooth surfaces. The objective is to test the hypothesis that certain factors are associated with the choice of restorative material (amalgam, composite, other) that DPBRN practitioners used to place these restorations.
Methods: A total of 182 DPBRN practitioner-investigators participated in this study, representing 4 US regions: Alabama/Mississippi, Florida/Georgia, Minnesota, and Permanente Dental Associates. Practitioner-investigators completed an enrollment questionnaire that included the dentist's age, gender, practice workload, practice type, and years since graduation. When a consented patient presented with a previously un-restored carious tooth, practitioner-investigators recorded certain patient and tooth characteristics. A total of 5,846 restorations of carious lesions were included. The primary analytic approach utilized generalized estimating equation (GEE) modeling to implement logistic regression analysis, accounting for correlated observations due to multiple restorations conducted by the same dentist and up to four restorations within the same patient.
Results: Overall, amalgam was used more often than direct composite and other materials (52%, 44%, and 4%, respectively). For practitioners who placed amalgam, predictors were type of practice (p<0.001); patient's gender and age (p<0.001); dental insurance (p=0.017); tooth location and surface (p<0.001); and pre-operative depth (p<0.001). For direct resin-based composite, predictors were type of practice (p<0.001); patient's age (p<0.001), race (p=0.041), and gender (p<0.001); dental insurance (p=0.005); tooth location (p<0.001); and pre-and post-operative depths (p=.0005 and p=0.037, respectively). For other materials, the predictors were age of the patient (p<0.001), pre-operative depth (p<0.001), and use of rubber dam (p=0.022).
Conclusions: Amalgam remains a material commonly used by US dentists to restore posterior caries lesions. The results illustrate there are numerous patient, practitioner, and restoration-level characteristics that predict material use for amalgam, direct resin-based composite and other materials.