Comparison of the reproducibility of storage phosphor and film bitewings for assessment of alveolar bone loss.

OBJECTIVE: To compare bitewing storage phosphor images and a digital measuring method with bitewing films and an analog measuring method with regard to the reproducibility of measurements of alveolar bone loss. MATERIAL AND METHODS: Nine participants randomly selected from an epidemiological study were radiographically examined using two modalities: bitewing SP images and bitewing films. A digital measuring method was used on the bitewing SP images and an analog measuring method on the bitewing films. Alveolar bone loss was measured at 12 index sites in the premolar/molar region per participant and modality. One hundred measured sites on each modality were assessed twice by three observers. Paired t-test values and intra-class correlation coefficient (ICC) were computed. RESULTS: Comparison of the mean absolute difference of alveolar bone loss between the digital and analog measuring methods demonstrated comparable results (p=0.53). The absolute difference in millimetres between 1st and 2nd measurements was comparable for two observers and statistically different for one. Intra-observer performance between 1st and 2nd measurements was comparable for the digital (ICC=0.85) and analog (ICC=0.83) measuring methods. Inter-observer agreement for the digital measurements was higher (ICC=0.79) than for the analog measurements (ICC=0.64). CONCLUSIONS: The study demonstrates that digital and analog measuring methods are comparable with regard to absolute alveolar bone measurements and intra-observer agreement. Inter-observer comparison demonstrated significantly higher agreement for the digital measurements. Based on the overall results, the modalities with the measuring methods utilized are comparable when measuring minor alveolar bone loss.

Root length in transplanted premolars.

The objectives of the present prospective longitudinal study were to establish the survival and success rates for premolars with partly developed roots transplanted according to a set protocol, and to analyze the effect of varying pre-surgery root development on final root length. Standardized periapical radiographs of 132 consecutively transplanted premolars were obtained at predetermined intervals over a 4-year follow-up period. Survival and success rates were calculated on the basis of presence of teeth and recording of defined radiological variables, respectively. Final root length was compared to normative metric data for root morphology. From the total sample, 54 patients with 68 transplanted premolars suitable for analysis of root growth relative to initial root length were identified, and divided into subsamples according to root length pre-transplantation. Survival rates were 100% after 1, 2, and 3 years, and 98.6% 4 years post-transplantation. The success rates were 92.9%, 92.8%, 89%, and 90.5% in subsamples collected 1, 2, 3, and 4 years after transplantation, respectively. The transplants obtained on average 78% of normative root length, and by dichotomizing the transplanted teeth in subsamples with 'short' and 'long' roots pre-surgery, similar final root lengths were observed even if 'short' roots had the greatest increase. Very early transplantation (roots < 7 mm), however, tended to result in short final root length. It is concluded that the success and survival rates were comparable to results obtained in similar studies. Initial root length was a significant predictor of root length increase. Transplanting teeth with short roots is to risk short final root length.