IADR Abstract Archives
Measurement Of Occlusal Equilibration Following Hall Crown Placement; Pilot Study.
Objectives: The Hall Technique involves fitting stainless steel crowns without local anaesthesia, tooth preparation or caries removal, sealing-in caries. Following crown placement the occlusion is ‘propped open’ on the crown. Past studies have noted this resolves. This study aimed to determine the occlusal re-equilibration timeframe and compensation source using four measurement methods.
Methods: Children, 4-8 years old due to have crowns fitted were recruited. Occluso-vertical dimension (OVD) was measured using: 1)intra-oral clinical measurement of canine overlap; 2)clinical photographs; 3)impressions for study models (all taken before and after crown placement and at each follow-up appointment); and 4)digitally scanned study models (using Nextengine 3D desktop laser scanner); images superimposed and height changes in crowned, surrounding and opposing teeth measured with Geomagic® Control™software.
Results: 10 participants (mean 6.75 years) attended for crown fit and follow-up appointments at 2-weeks, 6-weeks and in four cases 6-months. One failed to re-attend following crown fitting. Reliability: Photographs- Intraclass Correlation Coefficient (ICC) inter-rater 0.91-0.96 and intra-rater 0.72-0.92; Study models- ICC inter-rater 0.80-0.90 and intra-rater 0.70-0.94. Measurement of digital subtraction images showed a high degree of reliability between digitally scanned model measurements; ICC 0.96 for inter-rater and 0.97 for intra-rater. OVD mean increased by 1.1mm immediately following crown placement, decreasing to 0.3mm at two-week follow-up, and staying around this level for the remainder of the follow-up period (from photographs). Study models showed a similar pattern and clinical measurements were deemed unreliable due to operator inconsistency.
Conclusions: Photographs were more reliable than study models. Digital subtraction images’ measurements had a high degree of reliability. Sequential measurements suggest that following Hall Crown placement, the OVD returns to before crown-fit levels within two weeks. Initial comparisons of crown heights with digital serial study models suggest compensation is mainly but not completely from intrusion of the crowned tooth.
Methods: Children, 4-8 years old due to have crowns fitted were recruited. Occluso-vertical dimension (OVD) was measured using: 1)intra-oral clinical measurement of canine overlap; 2)clinical photographs; 3)impressions for study models (all taken before and after crown placement and at each follow-up appointment); and 4)digitally scanned study models (using Nextengine 3D desktop laser scanner); images superimposed and height changes in crowned, surrounding and opposing teeth measured with Geomagic® Control™software.
Results: 10 participants (mean 6.75 years) attended for crown fit and follow-up appointments at 2-weeks, 6-weeks and in four cases 6-months. One failed to re-attend following crown fitting. Reliability: Photographs- Intraclass Correlation Coefficient (ICC) inter-rater 0.91-0.96 and intra-rater 0.72-0.92; Study models- ICC inter-rater 0.80-0.90 and intra-rater 0.70-0.94. Measurement of digital subtraction images showed a high degree of reliability between digitally scanned model measurements; ICC 0.96 for inter-rater and 0.97 for intra-rater. OVD mean increased by 1.1mm immediately following crown placement, decreasing to 0.3mm at two-week follow-up, and staying around this level for the remainder of the follow-up period (from photographs). Study models showed a similar pattern and clinical measurements were deemed unreliable due to operator inconsistency.
Conclusions: Photographs were more reliable than study models. Digital subtraction images’ measurements had a high degree of reliability. Sequential measurements suggest that following Hall Crown placement, the OVD returns to before crown-fit levels within two weeks. Initial comparisons of crown heights with digital serial study models suggest compensation is mainly but not completely from intrusion of the crowned tooth.