Development of a clinical practice guideline for orthodontically induced external apical root resorption.

OBJECTIVES: To develop a clinical practice guideline on orthodontically induced external apical root resorption (EARR), with evidence-based and, when needed, consensus-based recommendations concerning diagnosis, risk factors, management during treatment, and after-treatment care. MATERIALS AND METHODS: The Appraisal of Guidelines for Research and Evaluation II instrument and the Dutch Method for Evidence-Based Guideline Development were used to develop the guideline. Based on a survey of all Dutch orthodontists, we formulated four clinical questions regarding EARR. To address these questions, we conducted systematic literature searches in MEDLINE and Embase, and we performed a systematic literature review. The quality of evidence was assessed with the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. After discussing the evidence, a Task Force formulated considerations and recommendations. The drafted guideline was sent for comments to all relevant stakeholders. RESULTS: Eight studies were included. The quality of evidence (GRADE) was rated as low or very low. Only the patient-related risk factors, 'gender' and 'age', showed a moderate quality of evidence. The Task Force formulated 13 final recommendations concerning the detection of EARR, risk factors, EARR management during treatment, and after-treatment care when EARR has occurred. Stakeholder consultation resulted in 51 comments on the drafted guideline. After processing the comments, the final guideline was authorized by the Dutch Association of Orthodontists. The entire process took 3 years. LIMITATIONS: The quality of the available evidence was mainly low, and patient-reported outcome measures were lacking. CONCLUSIONS/IMPLICATIONS: This clinical practice guideline allows clinicians to respond to EARR based on current knowledge, although the recommendations are weak due to low-quality evidence. It may reduce variation between practices and aid in providing patients appropriate information.

Floating norms and post-treatment overbite in open bite patients.

In this study, the clinical significance of three floating norm systems, the Bergen Box (BB), the Segner-Hasund Harmonybox 1 and 2 (SHH1 and SHH2), as well as the influence of treatment modalities for predicting results of an open bite treatment were investigated. In the BB and SHH1, patients with a steep mandibular plane angle or a skeletal open bite configuration (O1mand, O1mandmax, O1max, or N1mand) were considered 'high risk', while in the SHH2, only the configurations O1mand and O1mandmax were considered high risk. All other configurations were designated 'low risk'. It was postulated that in high risk patients, the overbite was likely to relapse into an open bite after retention. Cephalograms of 83 open bite patients taken before treatment (T1) and at the end of retention (T2) were studied. Patients designated as low risk generally had a normal overbite at T2 after treatment, regardless of which box was used. The risk configurations of the SHH1 and SHH2 at T1 were significant predictors of the overbite at T2, the first being slightly better compared with the SHH2. The main clinical values of the SHH1 and SHH2 are strongly supported by the relatively good success rate in distinguishing a low-risk configuration. Reliable prediction of the treatment results of high-risk patients with risk configurations according to the SHH is improved by evaluating treatment modalities. The posterior bite splint seemed to have a bite opening effect, while a bite closing effect was associated with the use of a removable retention appliance.

Changes in alveolar morphology during open bite treatment and prediction of treatment result.

It has been postulated that dentoalveolar height is enlarged by a compensation mechanism in long face subjects. In this study, dentoalveolar composition was studied in 83 open bite patients. It was found that increases in overbite during treatment coincided with vertical lengthening of the symphysis, which exceeded increments in lower face height. This vertical growth coincided mainly with an increase in the area of the symphysis. Furthermore, a retrusion of the maxillary incisors enhanced bite deepening. Stability of the overbite during the retention period was studied in a subset of 22 patients. It was found that retrusion of the maxillary incisors during treatment led to a more stable overbite during the retention period. Vertical lengthening of the symphysis relative to the increase in lower face height seemed to enhance bite opening during retention. Prediction of the overbite may be reliable, if a re-evaluation of the patients takes place during active treatment. The angle NTGoGn had a substantial predictive value (multiple R = 0.46) for post-treatment overbite. It is concluded that in open bite patients, a dentoalveolar compensation mechanism results in a stable overbite at the end of treatment by enlarging symphysial height through a moderate increase in symphysial volume. In addition, retrusion of the maxillary incisors contributes to overbite reduction. However, an excessive increase in vertical height of the symphysis relative to lower face height may relapse after active treatment. For prediction of the post-treatment overbite, the angle NTGoGn may be used, although a re-evaluation during treatment is recommended.