Objectives:
Interdental space is important for maintaining dental health because periodontitis is more prevalent and severe in this place than free surfaces. Conventional tooth brushing is not sufficient to clean and to keep clean, therefore interdental brush or floss silk is suggested as effective interdental cleaning aids. To test their cleaning efficacy, in vitro model with exact size and shape is useful although there was a short study regarding interdental space size. Therefore, this study aimed to develop new interdental space measurement method using 3-D virtual models.
Methods:
Maxillary dental casts from 22 young adults (mean age 24.23 +/- 0.69) and 22 middle-aged adults (mean age 49.82 +/- 7.23) were scanned and rendered as 3-D virtual models using the Autoscan system for a dental application. Seven reference points representing interdental space were registered on the virtual models buccal and lingual side, respectively. Two horizontal and frontal planes were generated using the reference points. The outer and inner circles were generated fitted to those planes based on least-squares method. The radii of circles were measured in both buccal and lingual interdental spaces, respectively. Mann-Whitney tests were applied to assess age-related differences in interdental space.
Results:
There were significant differences in the radii of all comparisons between two age groups (p /less/ .001), with the exception of outer circles of lingual interdental spaces (p = .098). The radii of interdental spaces were larger in the middle-aged group than a young group, within 0.206 - 0.454 mm. Especially, the maximum difference was shown in the inner circles of buccal interdental space. The inner circles representing the recession of interdental papilla were significantly larger in the middle-aged group in both buccal and lingual portions.
Conclusion:
In this study, a new measuring method using 3-D virtual models were developed and the differences between age groups were compared. These results can be used as meaningful references for designing interdental brushes and in vitro test model fabrication.
