Overjet reduction in relation to wear time with the van Beek activator combined with a microsensor


      • We investigated the association between overjet reduction and wear time.
      • Significant overjet reduction was achieved with a daily wear time of 8 hours.
      • Significant overjet reduction was achieved in a treatment period of at least 5 months.
      • A daily wear time of less than 8 hours showed no significant overjet reduction.
      • No patient achieved the prescribed wear time of 12 hour per day.


      The aim of this study was to use a microsensor to investigate the association among overjet reduction, treatment duration, and wear time of the van Beek activator.


      The study sample comprised patients (n = 28) with a mean age of 11.60 (±1.25) years at start of treatment treated with the van Beek activator. The prescribed wear time was 12 hours per day. The evaluation period was limited to the first 3 appointments. The wear times during the 3 intervals were assessed. Treatment periods with good compliance were characterized by a wear time of 8 hours or more per day.


      The medians of overjet were 9.00 mm at the start of treatment and 5.75 mm at the third appointment. The mean total wear time throughout the evaluation period was 7.75 (±3.66) hours per day. Significant correlations were found at the 3 intervals. Patients with a mean wear time of 8 hours or more per day achieved significantly greater overjet reductions. Patients with good compliance of at least 5 months showed significantly greater overjet reductions.


      Significant overjet reduction was achieved with a minimum daily wear time of 8 hours for at least 5 months. The level of compliance had a strong tendency to be maintained throughout the treatment period. No patient achieved the prescribed wear time of 12 hour per day.
      To read this article in full you will need to make a payment


        • Graber T.M.
        • Rakoski T.
        • Petrovic A.G.
        Dentofacial orthopedics with functional appliances.
        2nd ed. Mosby, St Louis1997
        • Bendeus M.
        • Hägg U.
        • Rabie B.
        Growth and treatment changes in patients treated with a headgear-activator appliance.
        Am J Orthod Dentofacial Orthop. 2002; 121: 376-384
        • Cura N.
        • Sarac M.
        • Ozturk Y.
        • Surmeli N.
        Orthodontic and orthopedic effects of Activator, Activator-HG combination, and Bass appliances: a comparative study.
        Am J Orthod Dentofacial Orthop. 1996; 110: 36-45
        • Ozturk Y.
        • Tankuter N.
        Class II: a comparison of activator and activator headgear combination appliances.
        Eur J Orthod. 1994; 16: 149-157
        • Sari Z.
        • Goyenc Y.
        • Doruk C.
        • Usumez S.
        Comparative evaluation of a new removable Jasper jumper functional appliance vs an activator-headgear combination.
        Angle Orthod. 2003; 73: 286-293
        • Altenburger E.
        • Ingervall B.
        The initial effects of the treatment of Class II, division 1 malocclusions with the van Beek activator compared with the effects of the Herren activator and an activator-headgear combination.
        Eur J Orthod. 1998; 20: 389-397
        • Weiland F.J.
        • Ingervall B.
        • Bantleon H.P.
        • Droacht H.
        Initial effects of treatment of Class II malocclusion with the Herren activator, activator-headgear combination, and Jasper jumper.
        Am J Orthod Dentofacial Orthop. 1997; 112: 19-27
        • Elgoyhen J.C.
        • Moyers R.E.
        • McNamara Jr., J.A.
        • Riolo M.L.
        Craniofacial adaptation of protrusive function in young rhesus monkeys.
        Am J Orthod. 1972; 62: 469-480
        • Wieslander L.
        Long-term effect of treatment with the headgear-Herbst appliance in the early mixed dentition. Stability or relapse?.
        Am J Orthod Dentofacial Orthop. 1993; 104: 319-329
        • Pancherz H.
        Treatment of Class II malocclusions by jumping the bite with the Herbst appliance. A cephalometric investigation.
        Am J Orthod. 1979; 76: 423-442
        • Omblus J.
        • Malmgren O.
        • Pancherz H.
        • Hägg U.
        • Hansen K.
        Long-term effects of Class II correction in Herbst and Bass therapy.
        Eur J Orthod. 1997; 19: 185-193
        • Pancherz H.
        • Hansen K.
        Occlusal changes during and after Herbst treatment: a cephalometric investigation.
        Eur J Orthod. 1986; 8: 215-228
        • Wieslander L.
        Intensive treatment of severe Class II malocclusions with a headgear-Herbst appliance in the early mixed dentition.
        Am J Orthod. 1984; 86: 1-13
        • van Beek H.
        Combination headgear-activator.
        J Clin Orthod. 1984; 18: 185-189
        • van Beek H.
        Overjet correction by a combined headgear and activator.
        Eur J Orthod. 1982; 4: 279-290
        • Phan K.L.
        • Bendeus M.
        • Hägg U.
        • Hansen K.
        • Rabie A.B.
        Comparison of the headgear activator and Herbst appliance—effects and post-treatment changes.
        Eur J Orthod. 2006; 28: 594-604
        • Ruf S.
        • Bendeus M.
        • Pancherz H.
        • Hägg U.
        Dentoskeletal effects and “effective” temporomandibular joint, maxilla and chin changes in good and bad responders to van Beek activator treatment.
        Angle Orthod. 2007; 77: 64-72
        • Schott T.C.
        • Ludwig B.
        Microelectronic wear-time documentation of removable orthodontic devices detects heterogeneous wear behavior and individualizes treatment planning.
        Am J Orthod Dentofacial Orthop. 2014; 146: 155-160
        • Schafer K.
        • Ludwig B.
        • Meyer-Gutknecht H.
        • Schott T.C.
        Quantifying patient adherence during active orthodontic treatment with removable appliances using microelectronic wear-time documentation.
        Eur J Orthod. 2015; 37: 73-80
        • Witt E.
        • Bartsch A.
        • Sahm G.
        The wear-timing measuring device in orthodontics—cui bono? Reflections on the state-of-the-art in wear-timing measurement and compliance research in orthodontics.
        Fortschr Kieferorthop. 1991; 52: 117-125
        • Sahm G.
        • Bartsch A.
        • Witt E.
        Micro-electronic monitoring of functional appliance wear.
        Eur J Orthod. 1990; 12: 297-301
        • Schott T.C.
        • Schlipf C.
        • Glasl B.
        • Schwarzer C.L.
        • Weber J.
        • Ludwig B.
        Quantification of patient compliance with Hawley retainers and removable functional appliances during the retention phase.
        Am J Orthod Dentofacial Orthop. 2013; 144: 533-540
        • Pauls A.
        • Nienkemper M.
        • Panayotidis A.
        • Wilmes B.
        • Drescher D.
        Effects of wear time recording on the patient's compliance.
        Angle Orthod. 2013; 83: 1002-1008
        • Tsomos G.
        • Ludwig B.
        • Grossen J.
        • Pazera P.
        • Gkantidis N.
        Objective assessment of patient compliance with removable orthodontic appliances: a cross-sectional cohort study.
        Angle Orthod. 2014; 84: 56-61
        • Cole W.A.
        Accuracy of patient reporting as an indication of headgear compliance.
        Am J Orthod Dentofacial Orthop. 2002; 121: 419-423
        • Klages U.
        • Sergl H.G.
        • Burucker I.
        Relations between verbal behavior of the orthodontist and communicative cooperation of the patient in regular orthodontic visits.
        Am J Orthod Dentofacial Orthop. 1992; 102: 265-269
        • Bos A.
        • Kleverlaan C.J.
        • Hoogstraten J.
        • Prahl-Andersen B.
        • Kuitert R.
        Comparing subjective and objective measures of headgear compliance.
        Am J Orthod Dentofacial Orthop. 2007; 132: 801-805
        • Schott T.C.
        • Goz G.
        Wearing times of orthodontic devices as measured by the TheraMon® microsensor.
        J Orofac Orthop. 2011; 72: 103-110
        • Razali N.M.
        • Wah Y.B.
        Power comparisons of Shapiro-Wilk, Kolmogorov-Smirnov, Lilliefors and Anderson-Darling Tests.
        J Stat Modeling Analytics. 2011; 2: 21-33
        • Landis J.R.
        • Koch G.G.
        The measurement of observer agreement for categorical data.
        Biometrics. 1977; 33: 159-174
        • Baccetti T.
        • Stahl F.
        • McNamara Jr., J.A.
        Dentofacial growth changes in subjects with untreated Class II malocclusion from late puberty through young adulthood.
        Am J Orthod Dentofacial Orthop. 2009; 135: 148-154
        • Stahl F.
        • Baccetti T.
        • Franchi L.
        • McNamara Jr., J.A.
        Longitudinal growth changes in untreated subjects with Class II Division 1 malocclusion.
        Am J Orthod Dentofacial Orthop. 2008; 134: 125-137
        • Ackerman M.B.
        • Thornton B.
        Posttreatment compliance with removable maxillary retention in a teenage population: a short-term randomized clinical trial.
        Orthodontics (Chic.). 2011; 12: 22-27
        • Doll G.M.
        • Zentner A.
        • Klages U.
        • Sergl H.G.
        Relationship between patient discomfort, appliance acceptance and compliance in orthodontic therapy.
        J Orofac Orthop. 2000; 61: 398-413
        • Sergl H.G.
        • Klages U.
        • Zentner A.
        Functional and social discomfort during orthodontic treatment—effects on compliance and prediction of patients' adaptation by personality variables.
        Eur J Orthod. 2000; 22: 307-315