Reproducibility of the assessment of the Fränkel manoeuvre for the evaluation of sagittal skeletal discrepancies in Class II individuals.

OBJECTIVES: The Fränkel manoeuvre is a procedure by which the mandible of Class II individuals is postured forward in dental Class I relationship. The evaluation of the resulting facial profile provides information concerning the components determining the sagittal discrepancy. Data concerning the reproducibility of its assessment are not available. This study aimed to evaluate the intra-observer and inter-observer reproducibility of the assessment of the manoeuvre and to assess whether the amount of clinical experience affects its reproducibility. METHODS: Two lateral photographs, one in centric occlusion, and the other with the mandible postured forward (Fränkel manoeuvre) of 100 Angle Class II individuals aged between 9 and 13 years were evaluated by six orthodontists (T0). Each examiner was asked whether the facial profile worsen or not with the manoeuvre after being trained by an expert orthodontist. The test was repeated after 2 weeks interval (T1). Intra-observer and inter-observer agreement were evaluated by computing the Cohen's K. RESULTS: The agreement (K values) between observations (T0 versus T1) for each examiner ranged from 0.49 to 0.72. The overall agreement was 0.65 [95% confidence interval (CI) = 0.54-0.75]. The agreement in the group with less clinical experience was 0.61 (95% CI = 0.46-0.76), while it was 0.68 (95% CI = 0.53-0.83) in the more experienced group. The amount of clinical experience did not affect intra-observer agreement (P = 0.50). The overall agreement between the examiners and the trainer was 0.74 (95% CI = 0.65-0.83) and 0.73 (95% CI = 0.64-0.83) at T0 and T1 respectively. CONCLUSION: The assessment of the Fränkel manoeuvre is reproducible and it is not influenced by the amount of clinical experience.

Pain perception following first orthodontic archwire placement--thermoelastic vs superelastic alloys: a randomized controlled trial.

OBJECTIVES: Orthodontic thermoelastic archwires produce lighter and more biologic forces than superelastic archwires and could therefore offer the possibility of reducing initial orthodontic pain. Nevertheless, evidence concerning this issue is scarce. The aim of this study was to compare pain perception following first archwire placement in patients with thermal heat-activated (HANT) and superelastic (SE) nickel-titanium archwires. METHOD AND MATERIALS: Thirty subjects (11 males, 19 females; range, 11 to 26 years of age) were recruited. Metal brackets were bonded in the maxillary or mandibular arch. Round 0.016-inch HANT or 0.016-inch SE archwires were randomly placed and tied with elastic ligatures. Each patient was invited to score tooth pain for 7 days at different time points (8:00, 12:00, 16:00, 20:00, and 24:00) using the visual analog scale (VAS). RESULTS: In both groups, pain was highest at day 2 and lowest at day 7. Patients with HANT archwires had significantly lower VAS scores (P < .005) at days 2, 3, and 4 than subjects with SE archwires. This was also the case after adjusting for analgesic consumption, sports practicing, overlapping pain of different origin, and the concomitance of stressful events. The frequency of analgesic consumption was higher in the SE than in HANT group at day 3 (P < .05). No differences in pain perception were found between time points, nor was any correlation found between dental crowding and pain. No difference in pain perception was found between the maxillary and mandibular dental arches. CONCLUSION: Initial orthodontic pain is reduced when using HANT orthodontic archwires.

Relationship between molar dentoalveolar and craniofacial heights in children.

OBJECTIVES: The relationship between posterior dentoalveolar heights and craniofacial vertical pattern has been matter of debate. Increased posterior dentoalveolar heights have been reported to be present in long face subjects, while in few studies the amount of molar dentoalveolar heights was negatively influenced by the divergence of the jaws. This, in turn, was interpreted as a dentoalveolar compensatory mechanism by which the teeth and the alveolar process adapt to jaw relationship in order to maintain a functional occlusion. Although this dentoalveolar compensatory mechanism has been reported to be present in adults and in subjects with permanent dentition, currently it is not known whether it might occur also in an early phase of growth, i.e. before growth spurts. In this study we tested the hypothesis that a dentoalveolar compensatory mechanism is absent in children with still unexpressed vertical growth potential. METHODS AND MATERIALS: Cephalometric measurements obtained from 79 children younger than 9 were entered as independent variables in a multiple regression model. Maxillary and mandibular molar dentoalveolar heights were entered as dependent variables. RESULTS: Approximately 54% of the total variability was explained by the variability in anterior lower facial height (ANS-Me) and mandibular palatal plane angle (PP-MP). Both maxillary and mandibular molar dentoalveolar heights were significantly influenced by the length of the anterior lower facial heights as measured by ANSMe, and by the mandibulopalatal plane angle (PP-MP). Increases of ANS-Me and PP-MP had opposite effects on the amount of molar dentoalveolar heights. CONCLUSION: The findings suggest that an inverse relationship between posterior dentoalveolar heights and jaw divergence is already present when the vertical growth is stil incomplete.

Web-based randomised controlled trials in orthodontics.

Randomised controlled trials (RCT) are considered the best source of scientific evidence--the gold standard--when evaluating the efficacy of orthodontic treatments. Frequently, RCT are planned as multicentre trials, with the intention of increasing statistical power and raising the precision of outcome estimates. The management of large-scale RCT, however, requires even more thorough organisation than conventional RCT. Indeed, the need for high accuracy and standardisation in data collection, research aids, secretarial skills, staff and patient training, and organisational meetings, make these studies time-consuming, expensive and, in general, relatively complex to carry out well. A website was developed to support a large scale-orthodontic RCT which aimed to evaluate the efficacy of a functional appliance(www.ortodonzia.unina.it). Websites such as this can increase the quality of data collection, simplify the randomisation process, speed up data collection, and improve trial monitoring. Web-based RCT have the potential to help globalise orthodontic research and also increase our rate of acquisition of evidence in orthodontics.

The Relationship between molar dentoalveolar and craniofacial heights.

Excessive vertical growth of the posterior dentoalveolar region has been implicated in the etiology of the so-called long-face syndrome. In this study, we tested the hypothesis that molar dentoalveolar heights are positively related to vertical craniofacial features. Cephalometric measurements obtained from 82 adult subjects were entered as independent variables in a multiple regression model. Maxillary and mandibular molar dentoalveolar heights were entered as dependent variables. Approximately 70% of the total variance was explained by anterior lower facial height (ANS-Me) and the mandibular palatal plane angle (PP-MP). Increases of ANS-Me and PP-MP had opposite effects on the amount of molar dentoalveolar heights. The lowest values of molar dentoalveolar heights were found in subjects with a small ANS-Me distance but with a wide PP-MP angle. The findings suggest that individuals with a marked divergence of the jaws may also have a reduced molar dentoalveolar vertical development.