IADR Abstract Archives
RCT in the field: Statistical consequence of wear, the proband’s absence and lost-in-follow up
Objectives: In order to assess the long-term success of dental restorations, observational and clinical trials are developed at academic institutes or universities. An essential prerequisite to evaluate the performance of dental materials on the long run is the regular follow-up of patients. In case of the absence or non-appearance of the subjects, the statistical power is affected and Kaplan-Meier survival estimate turn obsolet and are not applicable.
Methods: A prospective clinical field study was established to evaluate the clinical performance of EquiaFil® with a nano-filled resin coating and the conventional Fuji IX GP fast® with LC coating (GPfast) according to the FDI restoration material evaluation criteria. 1002 fillings were placed by 144 private dental practitioners across germany. Fillings were evaluated annually for a period of 4 years by external axaminers according to FDI criteria.
Results: In 1778 examinations over a period of four years, 660 fillings were evaluated in the first follow-up (NU1), 510 in the second follow-up (NU2) and 357 fillings in the third follow-up (NU3). 383 fillings were evaluated in NU1/NU2, 347 the NU1/NU2/NU3 and only 97 fillings are evaluated in the NU1/NU2/NU3/NU4. 68 restorations were evaluated in the NU2, 63 in NU1/NU3, 37 in NU3, 33 in NU1/NU3/NU4 and 24 only in NU2/NU3.
Conclusions: The lost to follow-up patients in RCTs would lead to the problem of statistical interpretation of the time-effect. Kaplan-Meier survival analysis implements a better outcome because of missing regular follow-up evaluation. The change in the aesthetic, functional and biological parameters of direct fillings over time can be estimated using logistic mixed models adjusted to the influencing variables (age, sex, size, dentist and patient) and it is calculated in the odds-ratio for reintervention.
Methods: A prospective clinical field study was established to evaluate the clinical performance of EquiaFil® with a nano-filled resin coating and the conventional Fuji IX GP fast® with LC coating (GPfast) according to the FDI restoration material evaluation criteria. 1002 fillings were placed by 144 private dental practitioners across germany. Fillings were evaluated annually for a period of 4 years by external axaminers according to FDI criteria.
Results: In 1778 examinations over a period of four years, 660 fillings were evaluated in the first follow-up (NU1), 510 in the second follow-up (NU2) and 357 fillings in the third follow-up (NU3). 383 fillings were evaluated in NU1/NU2, 347 the NU1/NU2/NU3 and only 97 fillings are evaluated in the NU1/NU2/NU3/NU4. 68 restorations were evaluated in the NU2, 63 in NU1/NU3, 37 in NU3, 33 in NU1/NU3/NU4 and 24 only in NU2/NU3.
Conclusions: The lost to follow-up patients in RCTs would lead to the problem of statistical interpretation of the time-effect. Kaplan-Meier survival analysis implements a better outcome because of missing regular follow-up evaluation. The change in the aesthetic, functional and biological parameters of direct fillings over time can be estimated using logistic mixed models adjusted to the influencing variables (age, sex, size, dentist and patient) and it is calculated in the odds-ratio for reintervention.