Table 3.
Predictors of exposed bone within 2 years after radiation therapy.
| COMPARISON | UNADJUSTED* | ADJUSTED† | ||||
|---|---|---|---|---|---|---|
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|
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| Relative Risk | 95% CI | P Value | Relative Risk | 95% CI | P Value | |
| Retained Hopeless Teeth vs Missing Pre-RT | 11.8 | 2.9 to 47.0 | .0005 | 18.7 | 4.0 to 88.1 | .0002 |
| Retained Hopeless Teeth vs Extracted Pre-RT | 2.9 | 0.6 to 13.9 | .17 | 6.4 | 1.2 to 35.2 | .034 |
| Extracted Pre-RT vs Missing Pre-RT | 4.0 | 1.1 to 14.2 | .031 | 2.9 | 0.83 to 10.5 | .096 |
| Untreated Caries vs Teeth Without Caries | 1.2 | 0.3 to 4.8 | .78 | 1.2 | 0.4 to 3.8 | .81 |
| Deepest Periodontal Pocket, mm | ||||||
| > 6 vs < 4 | 3.5 | 0.6 to 19.6 | .15 | 5.4 | 1.8 to 16.0 | .003 |
| 5 vs < 4 | 2.8 | 0.8 to 10.2 | .13 | 4.7 | 1.3 to 16.4 | .016 |
| 4 vs < 4 | 1.4 | 0.5 to 4.2 | .51 | 2.2 | 0.7 to 6.5 | .17 |
| Furcation Score | ||||||
| 2 vs 0 | 1.4 | 0.4 to 5.3 | .60 | 1.4 | 0.3 to 5.6 | .66 |
| 1 vs 0 | 0.3 | 0.1 to 1.0 | .056 | 0.3 | 0.1 to 1.1 | .063 |
| Gingival Recession, Cementoenamel Junction to Gingival Margin Distance, mm | ||||||
| < −2 vs ≥ 0 | 0.9 | 0.3 to 2.5 | .87 | 1.1 | 0.4 to 2.7 | .91 |
| −1 or −2 vs ≥ 0 | 1.6 | 0.5 to 5.7 | .46 | 2.4 | 0.6 to 9.5 | .20 |
| Mobility, Any Grade vs None | 4.5 | 1.1 to 18.2 | .032 | 3.7 | 0.9 to 15.3 | .071 |
| Bleeding on Probing, Yes vs No | 0.7 | 0.3 to 1.6 | .42 | 0.7 | 0.3 to 1.6 | .39 |
These analyses include the same participants and teeth included in the adjusted analyses. The adjusters had little missing data; unadjusted analyses including all participants and teeth (that is, that had the data needed for the unadjusted analysis) give nearly identical results.
Adjusted analyses omitted teeth with missing data for adjusters. With exceptions as noted, analyses were adjusted for these person-level characteristics: baseline [BL] status (had BL extractions vs had no BL extractions but at least 1 tooth declared hopeless at BL vs had no BL extractions or teeth declared hopeless), number of teeth extracted at BL, smoking status (current, former, never), enrollment site, primary radiation therapy (RT) site (5 categories listed in Table 1), and total dose to the primary site. Exceptions were for the tooth-level predictor BL tooth status (missing before pre-RT care, extracted during pre-RT care, hopeless, present and not hopeless), these adjusters were omitted: person-level BL status and number of teeth extracted at baseline. For furcation involvement, only molar teeth were included and only these adjusters were used: BL status (had BL extractions vs had no BL extractions but at least 1 tooth declared hopeless at BL vs had no BL extractions or teeth declared hopeless), number of teeth extracted at BL, and smoking status (current, former, never).