Cementum annulation and age determination in XXXX . I. Tooth variability and observer error.

@entity1 @entity2651 @entity235 @entity622 @entity1710 @entity2246
In order to test the feasibility of cementum annulations to estimate age in @entity1 , @entity2246 variability in cementum ring counts were evaluated in a sample of 42 mandibular @entity235 and first @entity2651 . Additionally, two sectioning techniques were evaluated. Demineralized thin sections (7 micron) stained with @entity1710 are the preferred technique since their age related variance is greater than 75% for all tooth types examined. In contrast, less than 50% of the total variance was accounted for among individuals when mineralized sections (80 micron) stained with @entity622 red were used. Intertooth variability in ring counts of demineralized sections was large between @entity235 and @entity2651 (43%). Premolars provide counts with lower interobserver error and are the preferred tooth. In an expanded sample (N = 51) of demineralized @entity2651 , intraobserver and interobserver error accounted for 2% and 5% of the total variance, respectively. Evaluation of several experimental designs showed that increasing the number of slides per tooth has the greatest effect on reducing variance followed by increasing the number of observers. Increasing the number of observations has little effect. Cementum ring counts are measurable to a highly repeatable extent and provide a level of repeatability greater than that reported for the pubic symphysis and auricular surface aging techniques.
