TABLE 1

Participants' Baseline Criteria (n = 176)

CharacteristicFindingValue
SexFemale126 (71.6%)
Male50 (28.4%)
Age at radioiodine treatment (y)Median48.4
Range17.6–86.3
Thyroid cancer entityPapillary110 (62.5%)
Follicular65 (36.9%)
Unspecified*1 (0.6%)
TNM stageT1, T2, T3, T422 (12.5%), 89 (50.6%), 24 (13.6%), 21 (11.9%)
Tx20 (11.4%)
N0, N1, N270 (39.8%), 29 (16.5%), 3 (1.7%)
Nx74 (42.0%)
M0, M151 (29.0%), 3 (1.7%)
Mx122 (69.3%)
Number of radioiodine treatment cycles1, 2, 3, 4, 5, 633, 125, 11†, 5†, 0, 2†
Median2
Range1–6
Cumulative 131I activity (GBq)‡≤3.7, 3.8–7.4, >7.428, 90, 58
Median7.4
Range1.9–35.0
131I score0, 1, 2, 3, 4128 (72.7%), 1 (0.6%), 7 (4.0%), 0 (0%), 17 (9.7%)
No scan23 (13.1%)
Follow-up (y)Median6.6
Range1.0–32.6
Observed period (patient-years)Before radioiodine8,472
After radioiodine1,421
Frequency of tooth brushing (per day)1, 2, 3, 410 (5.7%), 93 (52.8%), 49 (27.8%), 7 (4.0%)
>42 (1.1%)
No information15 (8.5%)
Additional dental care tools§0, 1, 2, 326 (14.8%), 72 (40.9%), 46 (26.1%), 13 (7.4%)
>31 (0.6%)
No information18 (10.2%)
Additional caries prevention‖No, yes136 (77.3%), 19 (10.8%)
No information21 (11.9%)
Xerostomia before radioiodine therapyNo, yes138 (78.4%), 2 (1.1%)
No information36 (20.5%)
Caries before radioiodine therapyNo, yes18 (10.2%), 69 (39.2)
No information89 (50.6%)
Tooth extractions before radioiodineNo, yes100 (56.8%), 21 (11.9%)
No information55 (31.3%)

  • ↵* One patient had received thyroidectomy in South Africa and pathologic files were unavailable.

  • ↵† Multiple treatment cycles (>2) were administered for reablation (6 cases) or metastatic disease (12 cases).

  • ↵‡ GBq = gigabequerels (convert values from gigabequerel to curies by dividing by 37).

  • ↵§ Dental floss, tooth picks, mouth rinsing.

  • ↵‖ Fluoride rail, fluoride gel, fluoridated tooth paste.

  • ↵ After written and oral invitation, the respective dentists were not willing or able to provide data.