Survival analysis of a miniplate and tube device designed to provide skeletal anchorage

IntroductionThe aim of this prospective cohort study was to compute the clinical survival and complication rates of a miniplate with a tube device (C-tube) used for orthodontic treatment.MethodsFrom August 2003 to May 2012, 217 patients were recruited. They received 341 C-tube miniplates. Some C-tube miniplates were removed because orthodontic treatment ended. Others remained beyond the study period and were recorded as censored data. Survival was classified as a C-tube miniplate that functioned in the mouth regardless of any complications. Success was defined as survival without complications. From the data, the effects of these clinical variables on the survival of the C-tube miniplates were evaluated: sex, age, jaw, placement sites, oral hygiene, tube clearance, inflammation, miniplate shape, number of screws, and length of the fixation screws. Survival analyses using the Kaplan-Meier method and the Cox proportional hazard model were applied.ResultsOf the 341 miniplates, 14 failed, and 32 had complications. Two-year survival and success rates were 0.91 and 0.80, respectively. In terms of the simple ratio statistic, this was equivalent to a success rate of 96%. The status of oral hygiene maintenance and the operators’ experience had significant associations with the complication rates (P <0.001).ConclusionsThe C-tube miniplate has an advantage in versatility in terms of force application. When placing a miniplate, the most important factor is maintaining good tissue health by means of good oral hygiene. Even with good hygiene, the doctor’s experience in performing the flap surgery was the second most important factor for success.