Initial effects of treatment of Class II malocclusion with the Herren activator, activator-headgear combination, and Jasper Jumper

Cephalometric effects of Twin-block and van Beek Headgear-Activator in the correction of Class II malocclusion

INTRODUCTION

The Twin-block (TB) and the van Beek Headgear-Activator (vBHGA) are indicated for patients with Class II malocclusion with a retrognathic mandible. Although the former is commonly prescribed for horizontally growing patients, the latter is often recommended for those growing vertically. This study aimed to compare the skeletal, dentoalveolar, and soft-tissue short-term effects of TB and vBHGA, taking growth patterns into account.

METHODS

Immediate prefunctional (T1) and postfunctional appliance (T2) lateral cephalometric radiographs were retrospectively obtained for vBHGA (n = 46), TB (n = 45), and untreated control (n = 45) groups. The interaction of several variables at T1, T2, and T2 - T1, as well as the resultant treatment effect, were analyzed using the analysis of covariance regression models at the 5% significance level.

RESULTS

Except for a greater reduction in Wits measurement (3.0 mm; P <0.0001) in the TB group, no anteroposterior (AP) skeletal difference was observed between the 2 appliances (ANB, 0.530; P = 0.07) (Harvold, 0.13 mm; P = 0.81). Both improved the AP skeletal relationship (ANB and Harvold) compared with the control (P <0.05). Although this mostly occurred because of the forward positioning of the mandible with the TB (SNB, 0.960; P = 0.01), the maxillary restriction was the main mechanism with the vBHGA (SNA, 1.590; P <0.01). Dentoalveolar compensations were more pronounced with the TB (IMPA, 1.92; P = 0.02), leading to greater overbite and overjet correction. Only the inclination of the maxillary incisors showed interaction with the growth pattern, with the TB horizontal growers experiencing more retroclination (U1-NA°. 3.620; P = 0.0067).

CONCLUSIONS

Both appliances produced similar modest AP skeletal changes that, together with dentoalveolar compensations, were able to correct the Class II malocclusion regardless of growth pattern.

Mechanical Characterization and Structural Analysis of Latex-Containing and Latex-Free Intermaxillary Orthodontic Elastics

Class II malocclusion is one of the most common dental anomalies and the use of intermaxillary elastomers is the standard method in its treatment. However, orthodontic elastics cannot exert continuous force over a period of time due to force degradation. Our goal was to mechanically characterize the different types of elastomers during static and cyclic loads, based on uniform methodology and examine the morphological changes after loading. Ten types of latex-containing and four latex-free intermaxillary elastics were examined from six different manufacturers. To determine the mechanical characteristics of the elastomers, tensile tests, cyclical tensile fatigue tests and 24 h relaxation tests were performed, and the elastics were also subjected to scanning electron microscopy (SEM) and Raman spectroscopy. Regardless of the manufacturer, the latex-containing elastomers did not show significant differences in the percentage of elongation at break during the tensile test. Only one type of latex-containing elastomer did not tear during the 24 h cyclical fatigue test. Fatigue was confirmed by electron microscopy images, and the pulling force reduced significantly. During the force relaxation test, only one latex-free ligature was torn; the force degradation was between 7.8% and 20.3% for latex ligatures and between 29.6% and 40.1% for latex-free elastomers. The results showed that dynamic loading was more damaging to ligatures than static loading, latex-containing elastomers were more resistant than latex-free elastics, and which observation could have clinical consequences or a potential effect on patient outcome.

Evaluation of soft-tissue changes in young adults treated with the Forsus fatigue-resistant device

INTRODUCTION

This study aimed to evaluate the effects of the Forsus fatigue-resistant device (FRD) EZ2 appliance (3M Unitek, Monrovia, Calif) on facial soft tissues by using images obtained from cephalometric radiographs and 3-dimensional (3D) facial scanning system.

METHODS

A total of 20 patients treated with the Forsus FRD EZ2 appliance were included in this study. The cervical vertebral maturation index was used to determine growth and development stages, and the subjects were investigated at cervical vertebral maturation stages 5 and 6 (ie, postpeak period). Three-dimensional facial scanning images were obtained with 3dMD Face (3dMD Ltd, Atlanta, Ga). Cephalometric radiographic images were taken before placement of the appliance (T0), immediately after removal (T1), and at the 6-month (T2) follow-up after the removal of the appliance. For comparison of the data, one-way repeated-measures analysis of variance and paired t test were used at P < 0.05.

RESULTS

Statistically significant changes were found in the Wits value, IMPA, L1P-NB (°), L1-NB (mm), L1P-APog, U1P-L1P, overjet, overbite, Ls-E, and labiomental angle in T0-T1. In T0-T2, statistically significant changes in the Wits, IMPA, L1P-NB (°), overjet, overbite and Ls-E values were observed.

CONCLUSIONS

The results revealed that the correction of malocclusion with Forsus FRD EZ2 appliance in patients at the postpeak period was mainly dentoalveolar. The soft tissues were affected to a limited extent. Three-dimensional facial scanning demonstrated similar accuracy and precision to traditional cephalometry, being a repeatable and accurate tool for linear and surface measurements.

Effects of Class II division 1 malocclusion treatment with three types of fixed functional appliances

Objective:

This study aimed at comparing the dentoskeletal changes in patients with Class II division 1 malocclusion, treated with three types of fixed functional appliances.

Methods:

A sample comprising 95 patients with the same malocclusion, retrospectively selected, and divided into four groups, was used: G1 consisted of 25 patients (mean age 12.77 ± 1.24 years) treated with Jasper Jumper appliance; G2, with 25 patients (mean age 12.58 ± 1.65 years) treated with the Herbst appliance; G3, with 23 patients (mean age 12.37 ± 1.72 years) treated with the Mandibular Protraction Appliance (MPA); and a Control Group (CG) comprised of 22 untreated subjects (mean age 12.66 ± 1.12 years). Intergroup comparison was performed with ANOVA, followed by Tukey test.

Results:

The Jasper Jumper and the Herbst group showed significantly greater maxillary anterior displacement restriction. The Jasper Jumper demonstrated significantly greater increase in the mandibular plane angle, as compared to the control group. The MPA group demonstrated significantly greater palatal inclination of the maxillary incisors. Vertical development of the maxillary molars was significantly greater in the Herbst group.

Conclusions:

Despite some intergroup differences in the amount of dentoskeletal changes, the appliances were effective in correcting the main features of Class II malocclusions.

Dentoskeletal effects produced by a Jasper Jumper with an anterior bite plane

OBJECTIVE

The aim of this retrospective study was to evaluate the dentoskeletal effects produced by a modified Jasper Jumper with an anterior bite plane for the correction of Class II division 1 malocclusion.

MATERIALS AND METHODS

A sample of 32 growing patients (mean age  =  11.9 ± 1.4 years) with Class II division 1 malocclusion and increased overbite were treated with a modified Jasper Jumper (JJ) and anterior bite plane protocol and compared with a matched control group of 30 subjects with untreated Class II malocclusion (mean age 12.2 ± 0.8 years). Lateral cephalograms were taken before treatment (T1) and at the end of comprehensive treatment (T2). Mean treatment duration was 2.1 ± 0.4 years. The T1-T2 changes in the two groups were compared with Student's t-tests for independent samples.

RESULTS

The JJ group was successfully treated to a Class I occlusal relationship with a significant reduction in overjet (-3.9 mm, P < .001) and overbite (-3.1 mm, P < .001). The JJ group exhibited a significant increase in mandibular length and a significant improvement in maxillomandibular sagittal skeletal relationships. The lower incisors were significantly proclined, while the lower first molars demonstrated significant movement in a mesial direction.

CONCLUSIONS

Use of a modified JJ appliance and anterior bite plane is an effective protocol for the treatment of Class II malocclusion with increased overbite and greater skeletal (75%) than dentoalveolar (25%) effects mainly at the mandibular level.

Combined fixed-functional treatment of skeletal class II malocclusions with the EVAA appliance: a preliminary study

OBJECTIVES

The aim of this study was to compare the skeletal and dental effects of the EVAA appliance with those of an activator appliance in growing children with skeletal Class II anomalies.

MATERIALS AND METHODS

A total of 34 subjects with Class II anomalies were recruited for this study. They were divided into three groups: the EVAA group (n=13; mean chronological age: 11 years 9 months), activator group (n=13; mean chronological age: 11 years 8 months) and control group (n=8; mean chronological age: 10 years 8 months). Lateral cephalometric radiographs were taken at the beginning and end of functional therapy. Fixed orthodontic treatment was completed in the EVAA group. A statistical software program (SPSS 18) was used for one-way analysis of variance and multiple comparisons with the Duncan test.

RESULTS

We observed a significant decrease in the ANB, convexity, and 1┴NA (°), while a significant increase appeared in upper anterior facial height, posterior facial height, 1┴NB (mm), SN-lower occlusal plane values in the EVAA and activator groups after treatment (p<0.05). No significant difference in study parameters in the control group during the treatment period except for the increase in SNA and 1┴NA (mm) values (p<0.05) were observed. There were no significant differences between EVAA and activator treatment groups in terms of study parameters except for the articular angle, which was significantly higher in the EVAA group after therapy (p<0.05).

CONCLUSION

The effects of EVAA appliances were similar to those of activator treatment.

Class II malocclusion treatment using Jasper Jumper appliance associated to intermaxillary elastics: a case report

INTRODUCTION

Skeletal, dental and profile discrepancies can be amended by using functional orthodontic appliances.

OBJECTIVE

This study is a report of the treatment of a patient, 11 years and 4 months old, with Class II, division 1, malocclusion, convex profile, protrusion of upper incisors, pronounced overjet and overbite, and mild crowding.

METHODS

The patient was treated with a Jasper Jumper associated to fixed appliances for 6 months and Class II intermaxillary elastics (3/16-in) during the last 4 months. After debonding, a Hawley retainer was used during daytime and a modified Bionator for night use during one year. In the lower dental arch a bonded lingual retainer was used. This treatment combination improved the profile, as well as the overjet, overbite and molar relation.

RESULTS

There was clockwise mandibular rotation and increase of lower anterior facial height. The lower incisors were protruded and extruded and the lower molars were extruded. The centric occlusal relation was checked and it was coincident to the maximum usual intercuspation.

CONCLUSIONS

It was demonstrated that the Jasper Jumper is an efficient alternative to Class II malocclusion treatment, providing improvement in the facial profile, although the changes are more dentoalveolar than skeletal.

Dentoskeletal changes induced by the Jasper jumper and the activator-headgear combination appliances followed by fixed orthodontic treatment

INTRODUCTION

The aim of this study was to compare the dentoskeletal changes of patients with Class II Division 1 malocclusion treated with either the Jasper jumper appliance or the activator-headgear combination, both associated with fixed appliances.

METHODS

The sample comprised 72 subjects with Class II Division 1 malocclusion divided into 3 groups: group 1 included 25 subjects treated with fixed appliances and the force modules of the Jasper jumper at an initial mean age of 12.72 years, group 2 included 25 subjects treated with the activator-headgear combination followed by fixed appliances at an initial mean age of 11.07 years, and group 3 included 22 untreated subjects at an initial mean age of 12.67 years. Initial cephalometric characteristics and dentoskeletal changes were compared with analysis of variance.

RESULTS

Both experimental groups had similar dentoskeletal changes: restrictive effect on the maxilla, clockwise mandibular rotation and a slight increase in anterior face height, retrusion of the maxillary incisors, distalization of the maxillary molars, protrusion of the mandibular incisors, extrusion of the mandibular molars, and significant improvements of the maxillomandibular relationship, overjet, overbite, and the molar relationship.

CONCLUSIONS

The effects of the Jasper jumper and the activator-headgear combination followed by fixed orthodontic appliances were similar in Class II malocclusion treatment.

[Success rate and efficiency of activator treatment]

In a retrospective multicentre study, the success rate and efficiency of activator treatment were analysed. All patients from two University clinics (Giessen, Germany and Berne, Switzerland) that fulfilled the selection criteria (Class II division 1 malocclusion, activator treatment, no aplasia, no extraction of permanent teeth, no syndromes, no previous orthodontic treatment except transverse maxillary expansion, full available records) were included in the study. The subject material amounted to 222 patients with a mean age of 10.6 years. Patient records, lateral head films, and dental casts were evaluated. Treatment was classified as successful if the molar relationship improved by at least half to three-fourths cusp width depending on whether or not the leeway space was used during treatment. Group comparisons were carried out using Wilcoxon two-sample and Kruskal-Wallis tests. For discrete data, chi-square analysis was used and Fisher's exact test when the sample size was small. Stepwise logistic regression was also employed. The success rate was 64 per cent in Giessen and 66 per cent in Berne. The only factor that significantly (P¡0:001) influenced treatment success was the level of co-operation. In approximately 27 per cent of the patients at both centres, the post-treatment occlusion was an ideal Class I. In an additional 38 per cent of the patients, marked improvements in occlusal relationships were found. In subjects with Class II division 1 malocclusions, in which orthodontic treatment is performed by means of activators, a marked improvement of the Class II dental arch relationships can be expected in approximately 65% of subjects. Activator treatment is more efficient in the late than in the early mixed dentition.

Effectiveness of bionator therapy for Class II malocclusions: a comparative long-term study

OBJECTIVE

The goal of this retrospective study was to examine the effectiveness of isolated bionator therapy in Class II patients both longitudinally and over the long term. We aimed to determine whether skeletal and/or dentoalveolar reactions differ in relationship to the Angle Class (II, Division 1 vs. II, Division 2).

PATIENTS AND METHODS

A total of 50 juvenile patients with Class II malocclusion (♀ n = 26, ♂ n = 24) were included. A total of 24 patients presented an Angle Class II, Division 1 and 26 an Angle Class II, Division 2. We compared the patients' lateral cephalograms taken at the beginning of treatment (t1: 10.1 years), after active therapy (t2: 13.8 years), and at the end of retention (t3: 16.4 years) analyzing the following cephalometric parameters: SNA, SNB, ANB, ANB(ind), SNPog, Wits appraisal, U1-SN, U1-SpP, L1-MeGo, interincisal angle. Mean and standard deviations of each of the variables were calculated. Differences between t1-t2 and t2-t3 were tested for statistical significance. Changes in the variables were then analyzed biometrically for specific differences in terms of Angle Class (II, Division 1 vs. II, Division 2).

RESULTS

Between t1 and t2, SNB (p = 0.000) and SNPog (p = 0.000) increased significantly, as did ANB (p = 0.000), while the difference between ANB and ANB(ind) (p = 0.000) and Wits appraisal (p = 0.000) decreased significantly. The dentoalveolar variables U1-SN, U1-SpP, and the interincisal angle changed significantly in both groups. The inclination of the upper incisors was corrected by retrusion in the Class II, Division 1 and by protrusion in the Class II, Division 2 group. Only marginal changes in all variables between t2 and t3 were observed.

CONCLUSION

A significant skeletal effect (even in long-time stability) through bionator treatment could be confirmed in this study of Class II, Divisions 1 and 2 patients. The desired effect on the upper front teeth was realized, and there was no appreciable dentoalveolar compensation in the mandible.

Comparison of treatments with the Forsus fatigue resistant device in relation to skeletal maturity: a cephalometric and magnetic resonance imaging study

INTRODUCTION

The aim of this study was to compare the dentoskeletal changes and alterations of mandibular condyle-disc-fossa relationships in subjects at the peak and the end of the pubertal growth period treated with the Forsus fatigue resistant device (3M Unitek, Monrovia, Calif).

METHODS

The sample consisted of 29 subjects with Class II Division 1 malocclusions who were classified according to their hand-wrist radiographs. Fifteen patients were at or just before the peak phase of pubertal growth (peak pubertal group). Fourteen patients were near the end of the pubertal growth period (late pubertal group). The study was conducted by using lateral cephalometric radiographs and magnetic resonance images obtained at the beginning and at the end of the application of the Forsus fatigue resistant device. The treatment period was 9 months.

RESULTS

The Wilcoxon signed rank test was used to evaluate differences within groups. The changes observed in both groups were compared by using the Mann-Whitney U test. There were statistically significant group differences in mandibular length and ramus length, with significant increases of these parameters in the peak pubertal group (P <0.05). No significant differences were observed between the groups concerning dental parameters (P >0.05), with the exception of mandibular molar vertical movements, which were significantly greater in the peak pubertal group (P <0.05). Analysis of the magnetic resonance images showed no positional changes of the mandibular condyle in relation to the glenoid fossa in either group (P >0.05). Although the articular disc was positioned more anteriorly in the peak pubertal group compared with its pretreatment position (P <0.05), the position of the disc was still within the physiologic range. No significant intergroup difference was observed for disc-condyle relationship (P >0.05).

CONCLUSIONS

The Forsus fatigue resistant device did not appear to cause significant increases in mandibular dimensions in subjects in late puberty. According to the magnetic resonance image findings, Forsus treatment is not a risk factor for the development of temporomandibular dysfunction in subjects with no signs and clinical symptoms of dysfunction.

A retrospective cephalometric evaluation of dental changes with activator and activator headgear combination in the treatment of skeletal class II malocclusion

AIM

The aims of this study were to evaluate the dental changes brought about by activator and activator headgear combination (ACHG) and to determine whether we can achieve control over the lower incisor proclination which is a side effect of using functional appliances; or not, while treating cases of skeletal class II malocclusions.

METHODS

Lateral cephalograms of 45 skeletal class II division 1 patients were selected for the study. Fifteen of them were successfully treated with an Andresen activator and the other 15 with an activator headgear combination. Fifteen class II subjects who had declined treatment served as the control group. Cephalometric landmarks were marked by one author to avoid interobserver variability.

RESULTS

The results revealed that both the activator and the activator headgear combination significantly (p < 0.001) affected dental variables measured. The mandibular incisor proclination was effectively controlled in the activator headgear combination group.

CONCLUSION

An activator headgear combination would offer itself as a better option compared with activator alone in the treatment of skeletal class II malocclusions especially in cases with proclined mandibular incisors.

CLINICAL SIGNIFICANCE

When one of the treatment goals is to achieve a greater control over mandibular incisor proclination in the treatment of Skeletal Class II malocclusions, employing a combination of activator and headgear may substantially improve clinical outcomes.

Sagittal and vertical occlusal cephalometric analyses of Pancherz: Norms for Chinese children

INTRODUCTION

The aims of this research were to establish norms for the sagittal and vertical occlusal cephalometric analyses of Pancherz for Chinese children and compare them with those of a matched white sample.

METHODS

The material comprised lateral cephalograms of a random sample of 405 southern Chinese children (age, 12 years; 200 boys, 205 girls) and an additional sample of 86 British white children (age, 12 years; 43 boys, 43 girls) in Hong Kong. The radiographs were digitized twice.

RESULTS

Statistically significant sex differences were found for 9 of 11 parameters in the sagittal occlusal analysis, and 6 of 10 in the vertical occlusal analysis in the Chinese sample, whereas there were no sex differences in the sagittal occlusal analysis and only 2 differences in the vertical occlusal analysis in the white sample. Statistically significant ethnic differences were found for 5 parameters in boys and 8 in girls of the 11 parameters in the sagittal analysis. For the vertical analysis, 7 of 10 parameters in both sexes differed significantly.

CONCLUSIONS

For the sagittal and vertical occlusal analyses of Pancherz, separate sex-specific standards are needed for Chinese and white children.

Dentoskeletal changes induced by the Jasper jumper and cervical headgear appliances followed by fixed orthodontic treatment

INTRODUCTION The objective of this controlled clinical study was to compare the dentoskeletal effects of the Jasper jumper with those of cervical headgear, when both are used with edgewise appliances to correct Class II Division 1 malocclusion.

METHODS

Lateral cephalograms of 75 patients were divided into 3 groups of 25. The control group included untreated Class II children with an initial mean age of 11.82 years (range, 9.35-14.84 years); they were followed without treatment for a mean period of 1.95 years (range, 0.90-3.95 years). The Jasper jumper group had an initial mean age of 11.86 years (range, 9.45-14.94 years); they were treated for a mean period of 1.96 years (range, 0.93-3.98 years). The cervical headgear group had an initial mean age of 12.29 years (range, 9.95-15.24 years); they were treated for an average of 1.88 years (range, 0.95-3.95 years). Comparison of the initial measurements showed that the 3 groups were similar at pretreatment, thus allowing direct comparisons. Analysis of variance (ANOVA) and the Tukey test were applied for comparison of the groups.

RESULTS

Different appliances yielded specific effects on several components (skeletal and dentoalveolar) evaluated. Anterior maxillary growth was significantly restricted by the cervical headgear. Mandibular growth was similar in all 3 groups, although it was slightly greater in the Jasper jumper group. The experimental groups had similar improvements in maxillomandibular relationshipd. The pattern of craniofacial growth was not significantly different between groups. The most significant effect on the maxillary dentoalveolar component was retrusion of the maxillary incisors by the cervical headgear. The effects observed for the Jasper jumper group were primarily related to the mandibular dentoalveolar component, including labial tipping and protrusion of the mandibular incisors, and mesial movement and extrusion of the mandibular molars compared with the control group.

CONCLUSIONS

The headgear appliance corrected the Class II malocclusion mostly by anterior maxillary restriction and maxillary dentoalveolar effects. Correction of the Class II malocclusion with the Jasper jumper appliance was largely due to mandibular dentoalveolar effects rather than skeletal effects.

Effects of activator and high-pull headgear combination therapy: skeletal, dentoalveolar, and soft tissue profile changes

The aim of this study was to evaluate skeletal, dentoalveolar, and soft tissue profile changes with activator and high-pull headgear combination therapy in patients with Class II malocclusions caused by maxillary prognathism and mandibular retrognathism. The subjects, all in the mixed dentition, were selected from a single centre and were divided into two groups: 28 patients were treated with an incisor double capping activator and a high-pull headgear combination appliance (13 girls, 15 boys mean chronological age 11.7 +/- 1.2 years, skeletal age 12.1 +/- 1.4 years) and an untreated group of 28 subjects (14 girls, 14 boys mean chronological mean age 11.9 +/- 1.1 years, skeletal age 12.3 +/- 1.3 years). The skeletal, dentoalveolar, and soft tissue profile changes that occurred were compared on lateral cephalograms taken before treatment (T0) and after 1.1 +/- 0.3 years when the combination appliance was removed (T1). In the control group, the radiographs were obtained at the start (T0) and after an observation period 1.2 +/- 0.4 years (T1). Statistical analysis was undertaken with Wilcoxon's ranked-sum test for intra-group comparisons and differences between groups with t-test and Bonferroni's test at a level of significance of P < 0.05. Activator and high-pull headgear combination treatment in these growing patients resulted in a correction of the skeletal Class II relationship (ANB -3.4 degrees), a restriction of maxillary growth (SNA -2.0 degrees, OLp-A -2.3 mm), an advancement of the mandibular structures (SNB +2.6 degrees, FH-NPg +2.3 degrees, OLp-B +2.7 mm, OLp-Pg +2.2 mm), an increase in lower face height (ANS-Me +3.9 mm), a correction of the overjet (-5.4 mm), an improvement in overbite (-2.2 mm), uprighting of the maxillary incisors (U1-FH -5.3 degrees, OLp-U1 -2.5 mm), protrusion of the mandibular incisors (IMPA +2.0 degrees, OLp-L1 +2.7 mm), and a correction of the dental Class II malocclusion (OLp-L6 +3.5 mm). The soft tissue profile changes were a correction of facial convexity (G'-Sn-Pg' angle 2.3 degrees, Mlf-Li-x-axis angle 9.1 degrees), and an increase in lower antero-posterior (Mlf-y-axis 5.6 mm, Pg'-y-axis 5.3 mm), and lower vertical (Sls-x-axis 3.8 mm, Pg'-x-axis 3.8 mm, Me'-x-axis 5.1 mm) soft tissue dimensions. The mentolabial fold depth (Mlf-E line) also significantly decreased, -0.8 mm in the treated group. The activator and high-pull headgear combination appliance was effective in treating growing patients with maxillary prognathism, mandibular deficiency, and facial convexity by a combination of skeletal and dentoalveolar changes and improvement in the soft tissue facial profile.

Effects of activator and activator headgear treatment: comparison with untreated Class II subjects

The aims of this study were to determine whether the activator and activator headgear encourage mandibular growth, and whether there is any superiority of one appliance over the other or if the resultant changes are due to normal growth. Forty-nine skeletal Class II division 1 patients were selected. Thirty-three (13 females, 20 males; mean age 12.52 +/- 1.42 years) were treated with an Andresen activator and the remaining 16 (7 females, 9 males; mean age 13.04 +/- 1.47 years) with an activator headgear combination. Twenty Class II subjects (9 females, 11 males; mean age 12.57 +/- 1.11 years) who had previously refused treatment served as a control group. Cephalometric landmarks were marked and digitized by one author to avoid inter-observer variability. Nine angular and 12 linear measurements were established and measured using Vistadent AT software. A paired-sample t-test and an ANOVA test were used to statistically evaluate the findings. The results revealed that both the activator and the activator headgear combination significantly (P < 0.001) encouraged mandibular growth, but had little restraining effect on the maxilla. The mandibular incisors were more controlled in the activator headgear combination group. The resultant skeletal, dentoalveolar and soft tissue changes differed significantly from those due to growth.

True incisor intrusion attained during orthodontic treatment: A systematic review and meta-analysis

INTRODUCTION

The purpose of this meta-analysis was to quantify the amount of true incisor intrusion attained during orthodontic treatment.

METHODS

Electronic databases (PubMed, Medline, Medline In-Process & Other Non-Indexed Citations, all EBM reviews [Cochrane Database of Systematic Reviews, ASP Journal Club, DARE, and CCTR], Embase, Web of Science, and Lilacs) were searched with the help of a senior health sciences librarian. The goal was to identify clinical trials that assessed true incisor intrusion through cephalometric analysis and factored out craniofacial growth when required. From the selected abstracts, original articles were retrieved, and their references were hand searched for missing articles.

RESULTS

Twenty-eight articles met the initial inclusion criteria, but 24 were rejected because they did not quantify true incisor intrusion or factor out normal growth impact when required. The remaining 4 articles showed that true incisor intrusion is attainable (0.26 to 1.88 mm for the maxillary incisors and -0.19 to 2.84 mm for the mandibular incisors) but with large variability depending on the appliance used. A meta-analysis with results from the 2 articles that used the segmental technique was completed. The combined mean estimates of intrusion and 95% CI were 1.46 mm (1.05-1.86 mm) for the maxillary incisors and 1.90 mm (1.22-2.57 mm) for the mandibular incisors.

CONCLUSIONS

True incisor intrusion is achievable in both arches, but the clinical significance of the magnitude of true intrusion as the sole treatment option is questionable for patients with severe deepbite. In nongrowing patients, the segmented arch technique can produce 1.5 mm of incisor intrusion in the maxillary arch and 1.9 mm in the mandibular arch.

An assessment of skeletal and dental responses to the functional magnetic system (FMS)

Correction of a skeletal Class II malocclusion with functional appliances has been accepted as a viable treatment modality. However, its mechanism of action is still disputed. This retrospective study compared 20 Class II patients treated with the functional magnetic system (FMS) with Class I and Class II groups (the control groups) of 20 untreated subjects each. Dental and skeletal changes were compared using serial lateral cephalograms. The FMS group differed significantly from the control groups in 15 of 24 parameters. The great increase in articulare-gnathion distance (3.07 mm) attributed to the attractive magnetic component of the FMS dictates a prolonged propulsion of the mandible. The skeletal:dental response ratio was 1:2 for the anterior region and 1:1 for the posterior region. The dental and skeletal parameters demonstrated a synergistic response in the maxilla and a competitive response in the mandible. This means that greater maxillary molar distal movement and incisor retroclination resulted in a more significant restraint of point A. In contrast, increasing the mandibular molar mesial movement and the incisor proclination accompanied less advancement of the pogonion. Although the skeletal contribution to the resolution of the malocclusion was less than the dental contribution (anteriorly, one third), the functional correction response was found to be regulated by skeletal factors.

Posttreatment evaluation of the distal jet appliance

This study analyzed molar distalization with the distal jet appliance, its effect on the anchor teeth, and the outcome at the completion of orthodontic treatment. Pretreatment, after distalization, and posttreatment lateral cephalometric radiographs were evaluated for 21 adolescent girls and 12 adolescent boys. The mean age of the subjects at the time of the pretreatment radiograph was 12.8 +/- 2.2 years. The mean time for the correction of the Class II molar relationship was 6.7 +/- 1.7 months, and the mean total treatment time was 25.7 +/- 3.9 months. The results of this study showed that the distal jet appliance distalized the maxillary molars, but there was significant loss of anchorage. The distal jet also showed less tipping of the maxillary molars and better bodily movement of molars because the force was applied closer to the center of resistance. The observations of treatment outcome indicate that the 1.8-mm mean net anterior movement of the maxillary first molar was more than offset by the 4.8-mm mesial movement of the mandibular first molar. There was no significant increase in lower face height. Consequently the effect on the facial balance was negligible.

Current concepts on functional appliances and mandibular growth stimulation

The mode of action of functional appliances, particularly in relation to stimulating mandibular growth, is a controversial subject. Many of the reports concerning growth effects of functional appliances have been characterized by poor methodology. In assessing functional appliances, results from prospective randomized clinical trials should be given prominence. On the basis of available evidence, it cannot be concluded that functional appliances are effective in stimulating and increasing mandibular growth in the long term. Although favourable growth changes have been reported following phase 1 therapy, they are generally not substantial and long term stability appears to be poor.