Analysis of Class II patients, successfully treated with the straight-wire and Forsus appliances, based on cervical vertebral maturation status

Comparison of Skeletal Changes in the Temporomandibular Joint between the Twin Block Appliance and Fixed Functional Appliance: A Longitudinal Follow-up Study

Aim

This current study evaluated and compared the skeletal changes in the head of the condyle, glenoid fossa, and articular space between the twin block appliance and PowerScope™ a fixed functional appliance.

Materials and methods

This study was a pilot, randomized, single-blinded, assessing the skeletal changes in the components of the temporomandibular joint (TMJ) using cone-beam computed tomography (CBCT). The study was conducted in 20 subjects in the age range of 11-14 years with class II division 1 malocclusion. These subjects were distributed randomly between two groups with an allocation ratio of 1:1 (group I-twin block and group I-PowerScope™). Follow-ups of both groups were done till desirable skeletal correction was attained (clinical edge-to-edge incisor relation).

Results

Condylar parameters such as position, height, and length were evaluated bilaterally in the CBCT scans. After using both devices, there was an increase in all condylar qualities; however, the twin block appliance showed a more noticeable difference, which has been determined to be statistically significant. In the twin block group, there was an average decrease of 0.56 mm in the anterior articular space and an increase of 1.2 and 2.64 mm in the middle and posterior articular spaces, respectively. In the PowerScope™ group, there was an average decrease of 0.23 mm in the anterior articular space and an increase of 2.55 and 1.85 mm in the middle and posterior articular spaces, respectively. In the case of the twin block device, the change in glenoid fossa angle was observed to be 6.1 mm on both sides and a mean difference of 1.25 mm on the right-side and 1.75 mm on the left-side was observed in the case of PowerScope™. The difference was established to be significant with a p < 0.05 in all cases.

Conclusion

Condylar attributes increased after the application of both devices but the difference was more pronounced in the case of twin block appliances. The difference in articular space (middle and posterior) between the twin block group and PowerScope™ group, was not significant statistically. In the present study, the remodeling in the glenoid fossa was greater in the twin block group compared to the PowerScope™ group.

How to cite this article

Halapanavar B, MN P, Deshmukh S, et al. Comparison of Skeletal Changes in the Temporomandibular Joint between the Twin Block Appliance and Fixed Functional Appliance: A Longitudinal Follow-up Study. Int J Clin Pediatr Dent 2024;17(1):7-14.

Skeletal and dentoalveolar contributions during Class II correction with Forsus™ FRD appliances : Quantitative evaluation

PURPOSE

Primary objective of the study is to quantify and evaluate the skeletal and dental contributions during sagittal Class II correction with the Forsus™ fatigue resistant device (FRD; 3M Unitek Corp., Monrovia, CA, USA). Secondary objective is to evaluate the overall vertical, soft tissue and chin-throat relation changes with the Forsus™ appliance.

PATIENTS AND METHODS

A retrospective sample of 27 Class II patients treated with the Forsus™ FRD appliance was compared to 20 untreated control subjects who were matched according to age and craniofacial morphology. Pre-Forsus™ (T0) and Post-Forsus™ (T1) cephalograms were subjected to composite cephalometric analysis. Growth changes were subtracted from the treatment changes to obtain the treatment effects of the appliance. The data were analyzed using Student's t‑test and independent t test.

RESULTS

Significant differences were found between the treated and the control group in 16 of 29 measured variables. The overjet and molar relation improved by 4.23 mm and 4.49 mm, respectively. This was mainly achieved by backward movement of maxillary incisors (1.4 mm) and molars (1.22 mm) and forward movement of mandibular incisors (2.26 mm) and molars (2.70 mm). Overbite decreased by 2.24 mm with no changes in mandibular and nasal plane angles.

CONCLUSION

The Forsus™ FRD was effective in correcting Class II malocclusion mainly at the dentoalveolar level. The net skeletal and dentoalveolar contributions towards both overjet and molar correction was 13% and 87%, respectively. The improvement in soft tissue profile and chin-throat configuration was statistically insignificant.

Long-term effects of the Forsus Device in Class II division I patients treated at pre-peak, peak, and post-peak growth periods: A retrospective study

OBJECTIVES

To assess the long-term effects of the Forsus Fatigue Resistant Device (FFRD) for the correction of Class II division 1 malocclusion during pre-peak, peak, and post-peak growth periods.

MATERIALS AND METHODS

This retrospective study was conducted on 60 patients that received FFRD with concurrent full-fixed orthodontic appliances during pre-peak (n=18), peak (n=21) and post-peak (n=21) maturational stages. The FFRD groups were compared with 60 untreated Class II control subjects obtained from the University of Michigan growth study and matched by skeletal age, sex, and observation periods. Lateral cephalograms were obtained at three time-points: [T1] pre-treatment; [T2] end of comprehensive orthodontic treatment; and [T3] retention (average of 3 years in retention). Nineteen linear and angular measurements were recorded. Short-term (T1- T2) and long-term (T1-T3) treatment changes were analyzed using paired Wilcoxon Signed Rank tests.

RESULTS

In the pre-peak group, FFRD caused temporary restraint of maxillary growth and an increase in mandibular length at T1-T2 compared to controls. No significant differences were found at T2-T3 time points. The net changes (T1-T3) included a restraining effect on the maxilla and dentoalveolar compensation. In the peak group, maxillary restraint effect was seen at T1-T2, but this effect relapsed at T2-T3 time points. Similar to the pre-peak group, the net results (T1-T3) included maxillary headgear effect and dentoalveolar compensation. In the post-peak group, the net effects (T1-T3) of treatment included only dentoalveolar compensation.

CONCLUSIONS

Overall, Class II malocclusion correction with FFRD is stable at three years post-treatment and is mainly achieved by maxillary restraint and dentoalveolar compensation at the pre-peak and peak stages and dentoalveolar compensation during the post-peak stage.

Esthetic perception of facial profile changes in Class II patients treated with Herbst or Forsus appliances

OBJECTIVE

To evaluate the esthetic perceptions of orthodontists and laypersons for facial profile changes after orthodontic treatment using Herbst or Forsus appliances.

MATERIALS AND METHODS

Pre- and posttreatment facial profile contour images of 20 Class II patients treated with Herbst (group H; n = 10) and Forsus (group F; n = 10) appliances were analyzed by 30 orthodontists and 30 laypersons, who graded them from 1 (unattractive) to 10 (very attractive) using a visual analog scale. Two assessments were carried out with a 15 day-interval. In the first evaluation, 40 images were presented in a random sequence. In the second evaluation, initial and final facial profile images of each patient were randomly presented side by side. To compare groups in relation to treatment method, Mann-Whitney tests were used. To evaluate differences between time points, Wilcoxon tests were used.

RESULTS

In the first evaluation, there was a significant difference between initial and final images only for group H, for both laypersons (P = .017) and orthodontists (P = .037). There was also a significant difference between laypersons and orthodontists in their ratings of posttreatment Herbst appliance profiles (P = .028). There was no significant difference between initial and final facial profile images for group F and no significant differences between or within evaluator groups in their ratings of initial or final Forsus appliance profiles. In the second evaluation, there was a significant difference between appliance groups only for laypersons, who considered cases treated with the Herbst appliance more attractive than those treated with the Forsus (P = .031). Laypersons also considered Herbst profiles more attractive than did orthodontists (P = .047).

CONCLUSIONS

Class II malocclusion treatment using the Herbst appliance may produce a more esthetically improved facial profile silhouette compared with Forsus appliances. The magnitude of perceived changes may not be considered clinically relevant.

[Cephalometric evaluation of the effect of dynamax and monoblock appliances on vertical facial height in patients with distal malocclusion]

The most common abnormality in orthodontics is distal malocclusion. The patient will benefit more if is treated during active growth phase. Various types of functional appliances are used in order to control maxillary and mandibular growth. In this article we compared vertical changes in mandibular position as a result of 3 different distal malocclusion treatment methods. To this end, groups consisting of, 17 patients treated with dynamax appliance, 17 patients treated with Monoblock appliance, 16 patients treated with a Monoblock-Headgear combination were created. Research has shown that, treatment with removable functional appliances results in parallel downward positioning of mandible; treatment with semiremovable appliances results in backward and downward rotation of mandible and that the extraoral appliances are useless to control the lower facial height.

Dentoskeletal effects of the forsus™ fatigue resistance device in the treatment of class II malocclusion: A systematic review and meta-analysis

OBJECTIVE:

The aim of this systematic review and meta-analysis is to quantitatively compare previous studies that evaluated skeletal and dentoalveolar effects of the Forsus™ Fatigue Resistance Device (FRD) in the treatment of Class II malocclusion with a matched untreated control group.

MATERIALS AND METHODS:

Four electronic searches PubMed, Web of Science, Cochrane Library, and Science Direct that were limited to articles on human studies comparing the effect of Forsus appliance with a matched control group in the treatment of Class II malocclusion from the year (2000–2017). An additional manual search was carried out by examining the references of the included articles, SEARCH terms included; Forsus and Class II malocclusion. The quality of the included studies was assessed using the modified methodological score for clinical trials. The data were analyzed using Michael Borenstein's Comprehensive Meta-Analysis Software (V3.3.070, Biostat, Inc., US).

RESULTS:

Seven studies were included comprising 273 participants (Forsus group = 142; control group = 131). The results indicated a statistical significant skeletal effect of the Forsus appliance on increasing the occlusal plane only (P < 0.001). The results also indicated a statistical significant (P < 0.001) dentoalveolar effects of the Forsus appliance on the following outcomes; protruding, proclining, and intruding lower incisors; retroclining upper incisors, distalizing and intruding upper molars, as well as reducing overjet and overbite.

CONCLUSIONS:

The Forsus™ showed positive effects on the maxillary incisors and first molars as well as overjet and overbite. However, multiple negative effects were reported on the occlusal plane and lower incisors that need to be considered when using such appliance in treating Class II malocclusion.

Changes in airway dimensions and hyoid bone position following class II correction with forsus fatigue resistant device

OBJECTIVE

The objective of this study was to investigate the effects of fixed functional therapy on oropharyngeal airway dimensions and hyoid bone positions in Class II patients and make comparison with an untreated Class II group.

MATERIALS AND METHODS

Eighteen patients (8 girls, 10 boys; mean age 13.62 ± 1.92 years) who were treated with Forsus Fatique Resistant Device (FFRD) and 19 patients (11 girls, 8 boys; mean age 12.74 ± 0.91 years) who served as control were enrolled. Cephalograms were used to assess linear, angular, and area measurements. Intragroup comparisons were made by paired t and Wilcoxon tests and intergroup comparisons were performed by independent t test.

RESULTS

With respect to controls, FFRD group showed increased airway dimensions at soft palate (P < 0.05) and more forward positioning of the hyoid bone (P < 0.05). Dentoalveolar changes exhibited mesial movement of lower incisors and molars and reduction in overjet (P < 0.001) in FFRD group.

CONCLUSIONS

Positive effects in oropharyngeal airway dimensions and increased values of hyoid bone displacement to a more forward position were found after fixed functional therapy.

CLINICAL RELEVANCE

Treatment with fixed functional appliances is mostly based on mesial movement of mandibular dentition, which might influence changes in tongue posture. The present results might indicate that oropharyngeal airway dimensions may be affected by postural changes of the hyoid bone in consequence of dentoalveolar changes. Clinically, these may be considered especially in Class II cases with reduced airway dimensions.