Table 2.
Associations of individual potential predictor variables with use of amalgam or resin-based composite (RBC) *†
| Variable | Amalgam Number (%) |
RBC Number (%) |
p-value |
|---|---|---|---|
| n=3028 | n=2571 | ||
| Regional Participation | |||
| Restorations, by DPBRN Region | |||
| AL/MS | 663 (36.2) | 1171 (63.8) | < 0.0001 |
| FL/GA | 283 (26.5) | 785 (73.5) | |
| MN | 814 (75.7) | 262 (24.3) | |
| PDA | 1268 (78.2) | 353 (21.8) | |
| Practitioner and Practice Characteristics | |||
| Gender | |||
| Male | 2250 (50.8) | 2180 (49.2) | 0.0077 |
| Female | 778 (66.6) | 391 (33.4) | |
| Years Since Graduation | |||
| ≤ 5 | 536 (60.8) | 346 (39.2) | 0.0216 |
| 6-15 | 747 (68.9) | 337 (31.1) | |
| 16-19 | 495 (56.1) | 387 (43.9) | |
| 20 or more | 1175 (45.9) | 1386 (54.1) | |
| Type of Practice | |||
| Large group practice (4 or more practitioners) | 2064 (79.0) | 548 (21.0) | < 0.0001 |
| Small group practice (3 or fewer practitioners) | 947 (32.2) | 1993 (67.8) | |
| Public health practice | 17 (36.2) | 30 (63.8) | |
| Practice Workload | |||
| Too busy to treat all | 346 (58.3) | 248 (41.8) | 0.4021 |
| Provided care to all, but overburdened | 497 (52.7) | 447 (47.3) | |
| Provided care to all, but not overburdened | 1727 (55.9) | 1362 (44.1) | |
| Not busy enough | 357 (44.9) | 439 (55.1) | |
| Patient Characteristics | |||
| Gender | |||
| Male | 1516 (58.8) | 1064 (41.2) | < 0.0001 |
| Female | 1500 (49.9) | 1506 (50.1) | |
| Race | |||
| White or Caucasian | 2123 (51.0) | 2037 (49.0) | 0.0261 |
| Black or African-American | 381 (53.4) | 332 (46.6) | |
| Other (American Indian/Alaska Native/Asian/ Pacific Islander) |
205 (72.9) | 76 (27.1) | |
| Hispanic or Latino Ethnicity | |||
| Hispanic or Latino | 172 (49.0) | 179 (51.0) | 0.7834 |
| Not Hispanic or Latino | 2581 (52.8) | 2304 (47.2) | |
| Dental Insurance | |||
| Yes | 2657 (56.4) | 2055 (43.6) | 0.0398 |
| No | 367 (41.9) | 508 (58.1) | |
| Mean (SD) Age in years | 30.5 (15.2) | 27.5 (15.3) | <0.0001 |
| Caries Lesion Characteristics | |||
| Tooth Location | |||
| Molar | 2108 (54.3) | 1778 (45.8) | 0.0003 ‡ |
| Premolar | 920 (53.7) | 793 (46.3) | |
| Tooth Surface | |||
| Posterior multi-surface | 1104 (57.3) | 823 (42.7) | < 0.0001 |
| Posterior one surface | 1924 (52.4) | 1748 (47.6) | |
| occlusal | 765 (41.0) | 1101 (59.0) | < 0.0001 |
| mesial or distal | 796 (78.3) | 220 (21.7) | |
| buccal or lingual | 363 (45.9) | 427 (54.1) | |
| Depth estimated pre-operatively | |||
| E1, outer ½ enamel | 53 (25.1) | 158 (74.9) | < 0.0001 |
| E2, inner ½ enamel | 212 (33.7) | 417 (66.3) | |
| D1, outer ⅓ dentin | 1697 (56.6) | 1300 (43.4) | |
| D2, middle ⅓ dentin | 783 (59.6) | 531 (40.4) | |
| D3, inner ⅓ dentin | 214 (61.0) | 137 (39.0) | |
| Uncertain | 13 (40.6) | 19 (59.4) | |
| Depth as determined post-operatively | |||
| E1, outer ½ enamel | 40 (31.5) | 87 (68.5) | < 0.0001 |
| E2, inner ½ enamel | 143 (32.4) | 299 (67.7) | |
| D1, outer ⅓ dentin | 1399 (56.7) | 1069 (43.3) | |
| D2, middle ⅓ dentin | 1007 (55.2) | 816 (44.8) | |
| D3, inner ⅓ dentin | 425 (60.3) | 280 (29.7) | |
*
p-values from individual regression models accounting for clustering within practitioner
†
all counts are at the restoration level
‡
The association between tooth location and material was confounded by clustering in the data set, due to unequal numbers of restorations and varying proportions of material usage for different dentists. Appropriately accounting for clustering in the analysis demonstrated a significant association that was not apparent from the raw percentages.