Mechanisms of Class II correction induced by the crown Herbst appliance as a single-phase Class II therapy : 1 year follow-up

Background The objective of this study is to evaluate the skeletal and dentoalveolar effects of the crown Herbst appliance used alone for a single phase of therapy followed by a 1-year observation period. Methods Forty patients (mean age 13.6 ± 1.3 years) with a stable Class I occlusion 1 year following the treatment with the crown Herbst appliance were selected from a prospective sample of 180 consecutively treated Class II patients. No other appliances were used during treatment or during the follow-up period. The dentoskeletal changes were compared with a matched sample of untreated Class II subjects (mean age 13.9 ± 1.6 years). Lateral cephalograms were taken before treatment, after Herbst treatment (1 year), and after 1-year follow-up. Overcorrection was avoided intentionally. Results Treatment produced an increase in mandibular length, a decrease in ANB angle, and a restriction in the vertical growth of posterior maxilla. The maxillary molars moved backward and tipped distally. The lower incisors proclined markedly, and the upper incisors became retroclined. During the follow-up period, the changes primarily were dentoalveolar in nature, with marked rebound of the upper molars and lower incisors, resulting in some increases in overbite and overjet. Conclusions The occlusal correction of Class II malocclusion observed 1 year after the crown Herbst appliance as a single-phase therapy was achieved primary due to the dentoalveolar changes and only limited skeletal change occurred.publishersversionPeer reviewe

Control of mandibular incisors with the combined Herbst and completely customized lingual appliance - a pilot study

<p>Abstract</p> <p>Background</p> <p>The traditional Herbst appliance induces mandibular incisor proclination independent of the anchorage system used. The dental effects of the Herbst appliance as an element of a completely customized lingual orthodontic (LO) appliance (Incognito, 3 M) has not been analyzed yet and the aim of this paper was to measure the effect of mandibular incisor proclination using this Herbst-LO device.</p> <p>Methods</p> <p>Retrospective study. Inclusion criteria: a) Class II ≥ 5 mm molar relationship; b) Herbst appliance ≥ 9 months in situ; and c) finished active treatment. Incisor position was measured on digital models before treatment, on the digital target setup, and on digital models obtained at the day of debonding. All measurements were performed by one investigator.</p> <p>Results</p> <p>Twelve patients (8 females, 4 males) out of 632 cases treated with a lingual appliance were included in the study. The measurement error computed with Dahlberg's formula was 0.2°. Seven cases had planned (target setup) mandibular incisor uprighting (ccr), and five cases had proclination (clockwise rotation). There was no statistical difference (p > 0.05) between planned incisor rotations of the target setup and achieved incisor rotations at the day of debonding. The overall mean difference was 2.2° ± 1.0°.</p> <p>Conclusions</p> <p>The Incognito-Herbst combination is the first Herbst device with full control over mandibular incisor movement. Using this system, anchorage loss or anchorage gain is independent of the Herbst treatment. It depends only on the planned tooth position of the individual target setup.</p

Evaluation of bone thickness around the mental foramen for potential fixation of a bone-borne functional appliance: a computer tomography scan study

AIM: A mandible bone-borne Herbst appliance (MBBHA) would avoid the proclination of the lower incisors that occurs with any teeth-borne functional appliance. But mapping of the bone characteristics at potential fixation areas around the mental foramen has not been carried out so far. The aim of this computer tomographic (CT) study was to evaluate bone thickness at specific positions around the mental foramen. MATERIAL AND METHODS: CT scans of 60 randomly chosen adult Hong Kong Chinese subjects (mean age 28 ± 6.3 years) were used to measure the bi-cortical bone thickness in the mandible in the mental foramen area. The thickness of buccal and lingual cortical and cancellous bone was assessed at the following locations: 10 mm (A10 mm) and 5 mm (A5 mm) anterior, 10 mm (P10 mm) and 5 mm (P5 mm) posterior, and 5 mm (Inf5 mm) below the mental foramen. RESULTS: The amount of buccal cortical bone thickness ranged between 1.89 mm, 10 mm anterior of the mental foramen, and 2.16 mm, 10 mm posterior to its location. At the A10 mm level, cortical thickness showed a marginal statistically significant difference between A5 and A10 mm. The total amount of bone thickness ranged from 10.19 to 12.06 mm. CONCLUSION: At the locations studied around the mental foramen, a mean bicortical bone thickness of 10-12 mm was measured. No large variation in the thickness was found between bicortical bone thicknesses in the measured locations around the mental foramen. Thorough evaluation on a case-by-case basis is advisable

Cone beam computed tomography study of apical root resorption induced by Herbst appliance

Objective This study evaluated the frequency of root resorption during the orthodontic treatment with Herbst appliance by Cone Beam Computed Tomography (CBCT).Material and Methods The sample comprised 23 patients (11 men, 12 women; mean ages 15.76±1.75 years) with Class II division 1 malocclusion, treated with Herbst appliance. CBCT was obtained before treatment (T0) and after Herbst treatment (T1). All the dental roots, except third molars, were evaluated, and apical root resorption was determined using the axial guided navigation method. Paired t-tests and Wilcoxon T Test were used to compare the dependent samples in parametric and nonparametric cases, respectively. Chi-Square Test with Yates’ correction was used to evaluate the relationship between apical root resorption and gender. Results were considered at a significance level of 5%.Results Apical resorption was detected by CBCT in 57.96% of 980 roots that underwent Herbst appliance treatment. All patients had minimal resorption and there was no statistical significance between the genders.Conclusion CBCT three-dimensional evaluation showed association between Herbst appliance and minimal apical root resorption, mostly in the anchoring teeth, without clinical significance

Proportions of the aesthetic African-Caribbean face : idealized ratios, comparison with the golden proportion and perceptions of attractiveness

Abstract Background In the absence of clear guidelines for facial aesthetic surgery, most surgeons rely on expert intuitive judgement when planning aesthetic and reconstructive surgery. One of the most famous theories regarding “ideal” facial proportions is that of the golden proportion. However, there are conflicting opinions as to whether it can be used to assess facial attractiveness. The aim of this investigation was to assess facial ratios of professional black models and to compare the ratios with the golden proportion. Methods Forty photographs of male and female professional black models were collected. Observers were asked to assign a score from 1 to 10 (1 = not very attractive, 10 = very attractive). A total of 287 responses were analysed for grading behaviour according to various demographic factors by two groups of observers. The best graded photographs were compared with the least well-graded photographs to identify any differences in their facial ratios. The models’ facial ratios were calculated and compared with the golden proportion. Results Differences in grading behaviour were observed amongst the two assessment groups. Only one out of the 12 facial ratios was not significantly different from the golden proportion. Conclusions Only one facial ratio was observed to be similar to the golden proportion in professional model facial photographs. No correlation was found between facial ratios in professional black models with the golden proportion. It is proposed that an individualistic treatment for each ratio is a rather better method to guide future practice

Palatal implants are a good alternative to headgear: A randomized trial

Introduction: The objective of this study was to compare the effectiveness of midpalatal implants with that of headgear as methods of supplementing anchorage during orthodontic treatment. This was a randomized, clinical trial at the Chesterfield and North Derbyshire Royal Hospital NHS Trust and the Charles Clifford Dental Hospital, Sheffield, United Kingdom. Methods: Fifty-one orthodontic patients between the ages of 12 and 39 with absolute anchorage requirements were randomly allocated to receive either a midpalatal implant or headgear to reinforce orthodontic anchorage. The outcome measures of the trial were the surgical and orthodontic success rates of the implants, the number of visits, and the length of treatment time, and the success of treatment as judged by the peer assessment rating (PAR) score reductions and the patients’ attitudes to implant placement. Results: The surgical success rate of the implants was 75%, and the orthodontic success rate was more than 90%. Both implants and headgear proved to be effective methods of reinforcing anchorage. The total number of visits was greater in the implant group, but the overall treatment times were almost identical. There were no statistically significant differences between the 2 groups in PAR scores either at the start or the end of treatment, and the percentages of PAR score reductions were almost identical. The patients had no problems accepting midpalatal implants as a method of reinforcing anchorage. Conclusions: Midpalatal implants are an acceptable technique for reinforcing anchorage in orthodontic patients and a good alternative for patients who do not wish to wear headgear