Effectiveness and Stability of Anterior Open Bite Correction Using Temporary Skeletal Anchorage: Comparison to Surgical Outcomes

The skeletal and dental changes that occur following the intrusion of maxillary posterior teeth with temporary skeletal anchorage (TSA) and the stability of these changes over time were assessed in twelve patients (1 male, 11 females) with anterior open bite. A comparative sample of patients treated with maxillary osteotomy was frequency matched based on age and gender. Lateral cephalograms were obtained before treatment/surgery, at the end of treatment/post-surgery, and at least 6 months following the completion of treatment. All pretreatment measurements except overbite were similar, on average, between the two treatment groups. Positive overbite was achieved for all patients treated with TSA's (Pre-tx OB x  =-1.0mm, Post-tx OB x  = 2.7mm). Both groups showed a similarly small average change during the follow-up time period. Overbite correction via intrusion of maxillary posterior teeth using TADs appears to be an effective and stable treatment modality. A skeletal anterior open bite due to vertical excess in the posterior maxilla is one of the most difficult malocclusions to treat orthodontically. The preferred treatment of posterior tooth intrusion is not easy to obtain with traditional orthodontic mechanics and a combined orthodontic and surgical intervention is typically utilized for optimal treatment results. The complexity, risks, and morbidity associated with the surgery, and the financial burden to the patient have encouraged a search for alternative clinical approaches to correct vertical posterior maxillary excess leading to anterior open bite. With the recent application of Temporary Skeletal Anchorage, true posterior tooth intrusion can be achieved using traditional orthodontic appliances and a minimally invasive surgical procedure. The anterior open bite comprises only a small portion of orthodontic patients but, due to the complexities of its treatment, it has drawn much attention from clinicians over the past several decades. The National Health and Nutrition Estimates Survey (NHANES) III taken between the years 1989-1994 estimated the prevalence of anterior open bite, defined as overbite less than 0, to be 3.50 year-olds. Of these individuals, less than 1% had an open bite greater than 2 mm. When 2 ethnicity was evaluated, it was found that open bites greater than 2 mm were five times more prevalent in blacks than in whites or Hispanics 1. However, this study only evaluated the vertical relationship of the anterior teeth and did not differentiate possible etiologies. Various etiological factors have been associated with the development of an anterior open bite. These range from vertical skeletal …