Three-dimensional comparison of the skeletal and dentoalveolar effects of the Herbst and Pendulum appliances followed by fixed appliances: A CBCT study

OBJECTIVES

To compare three-dimensional (3D) skeletal and dentoalveolar effects of the Herbst and Pendulum appliances followed by fixed orthodontic treatment in growing patients.

SETTING AND SAMPLE POPULATION

A sample of 35 adolescents with cone-beam computed tomography scans obtained prior to Herbst and Pendulum treatment (T1) and immediately after fixed appliance treatment (T2).

MATERIALS AND METHODS

Patients with Class II malocclusion was assessed retrospectively and divided into two treatment groups: Herbst group (n = 17, age: 12.0 ± 1.6 years) and Pendulum group (n = 18, age: 12.1 ± 1.5 years), with a mean treatment duration of 2.8 ± 0.8 years and 2.5 ± 0.7 years, respectively. Reconstructions of the maxillomandibular and dentoalveolar regions and data in 3D were obtained relative to cranial base, maxillary and mandibular regional superimpositions. Treatment outcomes (T2-T1) were compared between both groups using t tests for independent samples (P<.05).

RESULTS

Significant increase in mandibular length was observed in the Herbst group (7.3 ± 3.5 mm) relative to the Pendulum group (4.6 ± 4.5 mm). Inferior and anterior displacements of Pogonion were 2.2 mm and 1.6 mm greater in the Herbst group, respectively. The mesial displacement of the lower first molars was significantly greater in the Herbst group (1.9 mm). The upper first molars had contrasting results in sagittal displacement, with 0.6 ± 1.7 mm of distal displacement with the Pendulum and 1.4 ± 2.1 mm of mesial displacement with the Herbst. Lower incisor projection and proclination were similar between groups.

CONCLUSIONS

The Herbst and Pendulum appliances followed by comprehensive orthodontic treatment effectively corrected Class II malocclusion in growing patients, but with differing skeletal and dentoalveolar effects.

Class II functional appliance treatment and dynamic three-dimensional mimic muscle evaluation

BACKGROUND

Functional appliances have skeletal and dentoalveolar treatment effects, but knowledge on their effect on facial expressions is limited.

OBJECTIVE

To analyse changes in facial expressions, using three-dimensional (3D) mimic muscle evaluation, in growing children with Class II malocclusion and large overjet, undergoing functional appliance treatment.

METHODS

Fifteen growing children with Class II division 1 malocclusion, selected prospectively, had dynamic 3D recordings of facial expressions prior to and 12 months after commencing functional appliance treatment. Facial expressions recorded were smile and lip pucker, and the movements of the oral commissures were analysed, as well as mouth width and its symmetry. A control group of fifteen age- and sex-matched growing children without immediate need for orthodontic treatment had similar recordings prior to and after a 12-month observation period.

RESULTS

In the treatment group, the Class II malocclusion in all children improved after 12 months of functional appliance wear. With regard to movements of the oral commissures, the initial recordings of the treatment group did not show any significant differences to the control group for neither smile nor lip pucker. Differences were noted however when looking at mouth width asymmetry, where this tended to become more symmetrical in the functional appliance treatment group, during rest and during smiling, while it became more asymmetrical in the untreated control group.

CONCLUSION

The use of removable functional appliances in children with Class II division 1 malocclusion may have a positive effect on mouth width symmetry when smiling, making it more symmetrical.

The Use of Mini-Plates for the Treatment of a High-Angle, Dual Bite, Class II Malocclusion

To present a case report of an orthodontic treatment of a high-angle, dual bite, Class II malocclusion without extractions and with the use of mini-plates. Class II malocclusion treatment protocols vary according to the morphological component of the malocclusion and the magnitude and direction of craniofacial growth. It is generally agreed that the cooperation of the patient and careful planning of anchorage are the key determinants of successful treatment. Protrusion of the upper and lower lip and a retrognathic mandible were the patient's chief concerns. The patient had learned to project her mandible forward to disguise the overjet. The patient's parents elected to correct the malocclusion with the use of bilateral infrazygomatic mini-plates. Pre-treatment condylar stabilization with an orthotic established a stable centric relation position, followed by mounting of the models on a semi-adjustable Panadent articulator. This allowed diagnosis and treatment planning from a stable condylar position and eliminated possible misdiagnosis due to the dual bite. Distal retraction and vertical control of the upper teeth enabled correction of the Class II malocclusion with minimal patient cooperation. Mini-plate-assisted treatment corrected the excessive overbite and overjet. The patient completed treatment with a stable occlusion and no longer postured her jaw forward. The parents and patient were completely satisfied with the positive treatment outcome. A 2-year follow-up confirmed the clinical stability.

The influence of text messages on the cooperation of Class II patients regarding the use of intermaxillary elastics

OBJECTIVES

To evaluate the influence of text messages on cooperation of Class II patients with the use of intermaxillary elastics.

MATERIALS AND METHODS

The sample consisted of 42 orthodontic patients (20 males and 22 females) aged between 14 and 34 years. They were randomly divided into one of the following two groups: a control group with 21 patients who did not receive messages and an experimental group with 21 patients who received motivational and reminder text messages. Messages were sent twice a week for a period of 3 months. The patients were instructed to wear the elastics all day, removing them only during meals and replacing them daily. All patients were instructed regarding the importance of cooperation. Measurements were performed with a digital caliper on plaster models at the beginning of elastics wear (T1) and 3 months later (T2). For intragroup and intergroup comparisons between T1 and T2, paired and unpaired t-tests, respectively, were used with a significance level of 5%.

RESULTS

Statistically significant differences were observed in the intra- and intergroup comparisons between T1 and T2. Both groups showed a decrease in the sagittal distance between upper and lower arches from T1 to T2, demonstrating the effective use of elastics. However, the experimental group showed a Class II correction that was 3.7 times greater than the control group ( P = .001).

CONCLUSIONS

Text messages had a positive influence on the cooperation of patients regarding the use of intermaxillary elastics in the orthodontic treatment of Class II malocclusion.

Three-dimensional assessment of the middle cranial fossa and central skull base following Herbst appliance treatment

OBJECTIVES:

The purpose of this three-dimensional (3D) study was to assess retrospectively the middle cranial fossa and central skull base of patients treated with the Herbst appliance (HA).

MATERIALS AND METHODS:

3D surface virtual models of 40 Class II, division 1 malocclusion patients were generated from cone-beam computed tomography (CBCT) acquired before treatment (T0) and after 8 months of HA treatment (T1). T0 and T1 3D models were superimposed volumetrically at the anterior cranial fossa. Twenty subjects who had been treated with the Herbst appliance (HAG) were compared to 20 subjects who were not treated orthopedically. The latter group served as a comparison control group (CG). Quantitative assessments of the location and directional changes were made with linear and angular measurements between anatomical landmarks. Qualitative assessments of the spatial behavior of the middle cranial fossa and central skull base relative to the anterior cranial fossa were displayed graphically for visualization with color maps and semitransparent overlays. Non-parametric tests were performed to compare the between the HAG and CG.

RESULTS:

Point-to-point linear measurements and skeletal rotation (pitch, roll, and yaw) changes were very small along the observational period and were not significantly different between HAG and CG. Visual analysis of color maps and overlays confirmed that no changes in the cranial base were associated with HA.

CONCLUSIONS:

HA therapy did not produce clinically significant changes in the middle cranial fossa and central skull base.

Three-dimensional positional assessment of glenoid fossae and mandibular condyles in patients with Class II subdivision malocclusion

OBJECTIVES

To test the null hypotheses that the positions of the glenoid fossae and mandibular condyles are identical on the Class I and Class II sides of patients with Class II subdivision malocclusion.

MATERIALS AND METHODS

Retrospective three-dimensional (3D) assessments of the positions of the glenoid fossae and mandibular condyles were made in patients with Class II malocclusion. Relative to a fiducial reference at the anterior cranial base, distances from the glenoid fossae and condyles were calculated in pretreatment cone beam computed tomographic scans of 82 patients: 41 with Class II and 41 with Class II subdivision malocclusions. The 3D distances from glenoid fossae to sella turcica in the X (right-left), Y (anterior-posterior), Z (inferior-superior) projections were calculated.

RESULTS

Patients with Class II malocclusion displayed a symmetric position of the glenoid fossae and condyles with no statistically significant differences between sides (P > .05), whereas patients with Class II subdivision showed asymmetry in the distance between the glenoid fossae and anterior cranial base or sella turcica (P < .05), with distally and laterally positioned glenoid fossae on the Class II side. (P < .05). Male patients had greater distances between glenoid fossae and anterior cranial fossae (P < .05). The condylar position relative to the glenoid fossae did not differ between the two malocclusion groups nor between males and females (P > .05).

CONCLUSIONS

The null hypotheses were rejected. Patients with Class II subdivision malocclusion displayed asymmetrically positioned right- and left-side glenoid fossae, with a distally and laterally positioned Class II side, although the condyles were symmetrically positioned within the glenoid fossae.

Changes in skeletal and dental relationship in Class II Division I malocclusion after rapid maxillary expansion: a prospective study

Objective

To assess skeletal and dental changes immediately after rapid maxillary expansion (RME) in Class II Division 1 malocclusion patients and after a retention period, using cone beam computed tomography (CBCT) imaging.

Methods

Seventeen children with Class II, Division 1 malocclusion and maxillary skeletal transverse deficiency underwent RME following the Haas protocol. CBCT were taken before treatment (T₁), at the end of the active expansion phase (T₂) and after a retention period of 6 months (T₃). The scanned images were measured anteroposteriorly (SNA, SNB, ANB, overjet and MR) and vertically (N-ANS, ANS-Me, N-Me and overbite).

Results

Significant differences were identified immediately after RME as the maxilla moved forward, the mandible moved downward, overjet increased and overbite decreased. During the retention period, the maxilla relapsed backwards and the mandible was displaced forward, leaving patients with an overall increase in anterior facial height.

Conclusion

RME treatment allowed more anterior than inferior positioning of the mandible during the retention period, thus significantly improving Class II dental relationship in 75% of the patients evaluated.

Comparative cephalometric study of Class II malocclusion treatment with Pendulum and Jones jig appliances followed by fixed corrective orthodontics

OBJECTIVE

The purpose of this study was to cephalometrically compare the skeletal and dentoalveolar effects in the treatment of Class II malocclusion with Pendulum and Jones jig appliances, followed by fixed corrective orthodontics, and to compare such effects to a control group.

METHODS

The sample was divided into three groups. Group 1: 18 patients treated with Pendulum, Group 2: 25 patients treated with Jones jig, and Group 3: 19 young subjects with untreated Class II malocclusions and initial mean age of 12.88 years. The chi-square test was applied to assess severity and gender distribution. Groups 1 and 2 were compared to the control group by means of the one-way ANOVA and Tukey tests in order to differentiate treatment changes from those occurred by craniofacial growth.

RESULTS

There were no significant changes among the three groups with regard to the components of the maxilla and the mandible, maxillomandibular relationship, cephalometric and tegumental pattern. Buccal tipping of mandibular incisors was significantly greater in the experimental groups and increased mesial angulation of the maxillary second molars was found in the Jones jig group. In the experimental groups, dental relationship, overbite and overjet were corrected.

CONCLUSIONS

It can be stated that the distalization achieved its purpose of correcting the Class II.

Dentoskeletal effects of Class II malocclusion treatment with the Twin Block appliance in a Brazilian sample: a prospective study

OBJECTIVE

The aim of this study was to assess the dentoskeletal effects of Class II malocclusion treatment performed with the Twin Block appliance.

METHODS

The experimental group comprised 20 individuals with initial mean age of 11.76 years and treated for a period of 1.13 years. The control group comprised 25 individuals with initial mean age of 11.39 years and a follow-up period of 1.07 years. Lateral cephalograms were taken at treatment onset and completion to assess treatment outcomes. Intergroup comparison was performed by means of the chi-square and independent t tests.

RESULTS

The Twin Block appliance did not show significant effects on the maxillary component. The mandibular component showed a statistically significant increase in the effective mandibular length (Co-Gn) and significant improvement in the maxillomandibular relationship. The maxillary and mandibular dentoalveolar components presented a significant inclination of anterior teeth in both arches. The maxillary incisors were lingually tipped and retruded, while the mandibular incisors were labially tipped and protruded.

CONCLUSIONS

The Twin Block appliance has great effectiveness for correction of skeletal Class II malocclusion in individuals with growth potential. Most changes are of dentoalveolar nature with a large component of tooth inclination associated with a significant skeletal effect on the mandible.

Dental and skeletal changes in patients with mandibular retrognathism following treatment with Herbst and pre-adjusted fixed appliance

Objective

To assess the dentoskeletal changes observed in treatment of Class II, division 1 malocclusion patients with mandibular retrognathism. Treatment was performed with the Herbst orthopedic appliance during 13 months (phase I) and pre-adjusted orthodontic fixed appliance (phase II).

Methods

Lateral cephalograms of 17 adolescents were taken in phase I onset (T₁) and completion (T₂); in the first thirteen months of phase II (T₃) and in phase II completion (T₄). Differences among the cephalometric variables were statistically analyzed (Bonferroni variance and multiple comparisons).

Results

From T₁ to T₄, 42% of overall maxillary growth was observed between T₁ and T₂ (P < 0.01), 40.3% between T₂ and T₃ (P < 0.05) and 17.7% between T₃ and T₄ (n.s.). As for overall mandibular movement, 48.2% was observed between T₁ and T₂ (P < 0.001) and 51.8% between T₂ and T₄ (P < 0.01) of which 15.1% was observed between T₂ and T₃ (n.s.) and 36.7% between T₃ and T₄ (P < 0.01). Class II molar relationship and overjet were properly corrected. The occlusal plane which rotated clockwise between T₁ and T₂, returned to its initial position between T₂ and T₃ remaining stable until T₄. The mandibular plane inclination did not change at any time during treatment.

Conclusion

Mandibular growth was significantly greater in comparison to maxillary, allowing sagittal maxillomandibular adjustment. The dentoalveolar changes (upper molar) that overcorrected the malocclusion in phase I, partially recurred in phase II, but did not hinder correction of the malocclusion. Facial type was preserved.

Changes on facial profile in the mixed dentition, from natural growth and induced by Balters' bionator appliance

OBJECTIVE

The purpose of this study was to evaluate the facial profile changes induced by Balters' bionator appliance in Class II division 1 patients, at mixed dentition stage.

METHODS

The sample consisted of 28 pre-pubertal individuals at stages 1 and 2 of skeletal maturation (CVM), which were divided into two groups. The experimental group consisted of 14 individuals (7 boys and 7 girls, initial mean age of 8y12m) which were treated with Balters' bionator appliance for 14.7 months. The effects of treatment were compared to a control group of 14 subjects (7 boys and 7 girls, initial mean age of 8y5m) with Class II malocclusion, division 1, not orthodontically treated, which were followed up for 15.4 months. The statistical analysis was performed using Student's t test, at a significance level of 5%.

RESULTS

The results showed that the Balters' bionator appliance promoted a significant increase on the mentolabial angle, in addition to demonstrating a tendency to reduce the facial skeletal convexity, to restrict the maxillary growth and to increase the nasolabial angle and the lower anterior facial height.

CONCLUSIONS

It can be concluded that the Balters' bionator appliance improved the facial profile of children treated at mixed dentition stage.

Mandibular growth and dentoalveolar development in the treatment of class II, division 1, malocclusion using Balters Bionator according to the skeletal maturation

OBJECTIVE

The purpose of the study was to evaluate the influence of the skeletal maturation in the mandibular and dentoalveolar growth and development during the Class II, division 1, malocclusion correction with Balters bionator.

METHODS

Three groups of children with Class II, division 1, malocclusion were evaluated. Two of them were treated for one year with the bionator of Balters appliance in different skeletal ages (Group 1: 6 children, 7 to 8 years old and Group 2: 10 children, 9 to 10 years old) and the other one was followed without treatment (

CONTROL GROUP

7 children, 8 to 9 years old). Lateral 45 degree cephalometric radiographs were used for the evaluation of the mandibular growth and dentoalveolar development. Tantalum metallic implants were used as fixed and stable references for radiograph superimposition and data acquisition. Student's t test was used in the statistical analysis of the displacement of the points in the condyle, ramus, mandibular base and dental points. One-fixed criteria analysis of variance was used to evaluate group differences (95% of level of significance).

RESULTS

The intragroup evaluation showed that all groups present significant skeletal growth for all points analyzed (1.2 to 3.7 mm), but in an intergroup comparison, the increments of the mandibular growth in the condyle, ramus and mandibular base were not statically different. For the dentoalveolar modifications, the less mature children showed greater labial inclination of the lower incisors (1.86 mm) and the most mature children showed greater first permanent molar extrusion (4.8 mm).

Dental and skeletal components of Class II open bite treatment with a modified Thurow appliance

INTRODUCTION

Due to the lack of studies that distinguish between dentoalveolar and basal changes caused by the Thurow appliance, this clinical study, carried out by the School of Dentistry--State University of São Paulo/Araraquara, aimed at assessing the dental and skeletal changes induced by modified Thurow appliance.

METHODS

The sample included an experimental group comprising 13 subjects aged between 7 and 10 years old, with Class II malocclusion and anterior open bite, and a control group comprising 22 subjects similar in age, sex and mandibular plane angle. Maxillary/mandibular, horizontal/vertical, dental/skeletal movements (ANS, PNS, U1, U6, Co, Go, Pog, L1, L6) were assessed, based on 14 landmarks, 8 angles (S-N-ANS, SNA, PPA, S-N-Pog, SNB, MPA, PP/MPA, ANB) and 3 linear measures (N-Me, ANS-Me, S-Go).

RESULTS

Treatment caused significantly greater angle decrease between the palatal and the mandibular plane on the experimental group, primarily due to an increase in the palatal plane angle. ANB, SNA and S-N-ANS angles significantly decreased more in patients from the experimental group. PNS was superiorly remodeled. Lower face height (ANS-Me) decreased in the experimental group and increased in the control group.

CONCLUSIONS

The modified Thurow appliance controlled vertical and horizontal displacements of the maxilla, rotated the maxilla and improved open bite malocclusion, decreasing lower facial height.

Flexural strength of mini-implants developed for Herbst appliance skeletal anchorage. A study in Minipigs br1 cadavers

OBJECTIVE

The present study was designed to verify if mini-implant prototypes (MIP) developed for Herbst appliance anchorage are capable of withstanding orthopedic forces, and to determine whether the flexural strength of these MIP varies depending on the site of insertion (maxilla and mandible).

METHODS

Thirteen MIP were inserted in three minipig cadavers (six in the maxilla and seven in the mandible). The specimens were prepared and submitted to mechanical testing. The mean and standard deviation were calculated for each region. A two-way Student's t test was used to compare the strength between the sites. A one-way Student's t test was performed to test the hypothesis. Orthopedic forces above 1.0 kgf were considered.

RESULTS

The MIP supported flexural strength higher than 1.0 kgf (13.8 ± 2.3 Kg, in the posterior region of the maxilla and 20.5 ± 5.2 Kg in the anterior region of the mandible) with a significantly lower flexural strength in the anterior region of the mandible (p < 0.05).

CONCLUSIONS

The MIP are capable of withstanding orthopedic forces, and are more resistant in the anterior region of the mandible than in the posterior region of the maxilla in Minipigs br1 cadavers.

Assessment of first molars sagittal and rotational position in Class II, division 1 malocclusion

OBJECTIVE

This study assessed the anterior-posterior positioning of the upper and lower first molars, and the degree of rotation of the upper first molars in individuals with Class II, division 1, malocclusion.

METHODS

Asymmetry I, an accurate device, was used to assess sixty sets of dental casts from 27 females and 33 males, aged between 12 and 21 years old, with bilateral Class II, division 1. The sagittal position of the molars was determined by positioning the casts onto the device, considering the midpalatal suture as a symmetry reference, and then measuring the distance between the mesial marginal ridge of the most distal molar and the mesial marginal ridge of its counterpart. With regard to the degree of rotation of the upper molar, the distance between landmarks on the mesial marginal ridge was measured. Chi-square test with a 5% significance level was used to verify the variation in molars position. Student's t test at 5% significance was used for statistical analysis.

RESULTS

A great number of lower molars mesially positioned was registered, and the comparison between the right and left sides also demonstrated a higher number of mesially positioned molars on the right side of both arches. The average rotation of the molars was found to be 0.76 mm and 0.93 mm for the right and left sides, respectively.

CONCLUSIONS

No statistically significant difference was detected between the mean values of molars mesialization regardless of the side and arch. Molars rotation, measured in millimeters, represented ¼ of Class II.

Effects of mandibular protraction appliance associated to fixed appliance in adults

OBJECTIVE

This retrospective study aimed to conduct a cephalometric evaluation of the skeletal, dental and soft tissue effects resulting from treatment of adult patients presenting Class II malocclusion, performed with a Mandibular Protraction Appliance (MPA) combined with a fixed orthodontic appliance.

METHODS

The sample consisted of teleradiographs obtained before and after treatment of 9 adult patients (initial mean age of 22.48 years) with bilateral Class II, division 1, malocclusion. Paired t test (p < 0.05) was applied to compare initial and final values.

RESULTS

t test revealed an increase in anteroinferior facial height and posterior facial height. The dental changes include: extrusion of upper incisors, buccal inclination, protrusion of lower incisors, mesialization and extrusion of mandibular molars. Regarding the soft tissue component, there was an increase in nasolabial angle in addition to upper lip retrusion.

CONCLUSIONS

The effects of treating Class II malocclusion adult patients, by means of using Mandibular Protraction Appliance (MPA) combined with a fixed appliance were mostly observed in the mandibular arch, and consisted of buccal inclination, protrusion and intrusion of incisors, and mesialization and extrusion of the molars.

Class II malocclusion treatment with the Herbst appliance in patients after the growth peak

OBJECTIVE

The objective of this study was to evaluate dentoskeletal effects in the treatment of Class II malocclusion performed with the Herbst appliance in patients at post-peak stage of growth.

METHODS

The sample consisted of 16 patients with Class II malocclusion and average initial and final ages of 14.04 (ranging from 11.50 to 35.66) and 17.14 (ranging from 13.68 to 38.64) years, respectively, who were treated for an mean time of 2.52 years. Lateral cephalograms were obtained at treatment onset (T1) and completion (T2) to evaluate the effects of therapy. Initial dental casts were also used to evaluate the overjet and the anteroposterior severity of molar relationship at treatment onset. The cephalometric changes between initial and final stages were compared by means of the non-parametric Wilcoxon test.

RESULTS

The results showed that the Herbst appliance did not promote significant changes in the maxillary component and the effective length of the mandible significantly increased without improving the maxillomandibular relationship. Changes in the maxillary and mandibular dentoalveolar components revealed that the maxillary incisors exhibited retrusion and lingual tipping, while the mandibular incisors presented increased protrusion and buccal tipping. The dental relationships exhibited significant improvements with the treatment.

CONCLUSION

Based on the present results, it was concluded that the effects of treatment performed with the Herbst appliance in patients at post-peak stage of growth are predominantly of dentoalveolar nature.

Fixed lingual mandibular growth modificator: a new appliance for class II correction

INTRODUCTION

This article demonstrates the description and use of a new appliance for Class II correction.

MATERIAL AND METHODS

A case report of a 10-year 5 month-old girl who presented with a skeletally-based Class II division 1 malocclusion (ANB = 6.5°) on a slightly low-angle pattern, with ML-NSL angle of 30° and ML-NL angle of 22.5°. Overjet was increased (7 mm) and associated with a deep bite.

RESULTS

Overjet and overbite reduction was undertaken with the new appliance, Fixed Lingual Mandibular Growth Modificator (FLMGM).

CONCLUSIONS

FLMGM may be effective in stimulating the growth of the mandible and correcting skeletal Class II malocclusions. Clinicians can benefit from the unique clinical advantages that FLMGM provides, such as easy handling and full integration with bracketed appliance at any phase.

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.

Stability of molar relationship after non-extraction Class II malocclusion treatment

OBJECTIVE

This study aimed to evaluate the stability of molar relationship after non-extraction treatment of Class II malocclusion.

METHODS

The sample comprised 39 subjects (16 females, 23 males) with initial Class II malocclusion treated with no extractions, using fixed appliances. Mean age at the beginning of treatment was 12.94 years, at the end of treatment was 15.14 years and at post-retention stage was 21.18 years. Mean treatment time was 2.19 years and mean time of post-treatment evaluation was 6.12 years. To verify the influence of the severity of initial Class II molar relationship in stability of molar relationship, the sample was divided into two groups, one presenting a ½-cusp or ¾-cusp Class II molar relationship, and the other with full-cusp Class II molar relationship. In dental casts from initial, final and post-retention stages, molar, first and second premolars and canine relationships were measured. Data obtained were analyzed by dependent ANOVA, Tukey and Pearson's correlation tests, as well as independent t test between the two groups divided by severity of initial molar relationship.

RESULTS

There was a non-statistically significant 0.12-mm relapse of molar relationship. The initial severity of Class II molar relationship was not correlated to relapse in the post-retention period. When compared, the two groups showed no difference in relapse of molar relationship.

CONCLUSIONS

It was concluded that correction of Class II molar relationship is stable and initial severity does not influence relapse of molar relationship.