Long-term stability of dentoalveolar and skeletal changes after activator-headgear treatment

Long-term stability after high-pull headgear combined with fixed appliances: A retrospective cohort study of growing class II patients

BACKGROUND

High-pull headgear with fixed appliances is a common therapeutic plan in class II growing individuals, especially in those with a tendency to hyperdivergence. The stability of this approach has not been adequately assessed in the long-term. The aim of this retrospective study was to assess that long-term stability by means of lateral cephalograms. Seventy-four consecutive patients were included and examined at three time-points: pre-treatment (T1), end of treatment (T2), and at least five years post-treatment (T3).

RESULTS

The average initial age of the sample was 9.3 years (standard deviation, SD: 1.6). At T1, the mean ANB was 5.1 degrees (SD: 1.6), the mean SN-PP 5.6 (SD: 3.0) and the mean MP-PP 28.7 degrees (SD: 4.0). The median follow-up time was 8.6 years with an interquartile range of 2.7. A statistically significant, but of small magnitude increase in the SNA angle was noted at T3 compared to T2 after adjusting for the pre-treatment SNA value (mean difference (MD): 0.75; 95% CI: 0.34, 1.15; P<0.001). The inclination of the palatal plane appeared stable in the post-treatment period, while the MP-PP angle showed scarce evidence of decrease during the post-treatment period after adjusting for sex, pre-treatment SNA and SN-PP angles (MD: -2.29; 95% CI: -2.85, -1.74; P<0.001).

CONCLUSIONS

The sagittal position of the maxilla and the inclination of the palatal plane appeared to be stable after treatment with high-pull headgear and fixed appliances in the long-term. Continuous mandibular growth, both sagittaly and vertically, contributed to the stability of class II correction.

Does mandibular advancement with clear aligners have the same skeletal and dentoalveolar effects as traditional functional appliances?

BACKGROUND

The study aimed to compare the dentoskeletal effects of Vanbeek Activator, Herbst, Twin-Block and Mandibular Advancement with clear aligners in children with skeletal Class II malocclusions.

METHODS

A sample with sixty-three patients (37 males, 26 females) was included and divided into untreated control group (C, n = 12), Vanbeek Activator group (V, n = 14), Herbst group (H, n = 11), Twin-Block group (TB, n = 12) and MA group (MA, n = 14). Cephalometric analysis and Johnston Pitchfork analysis were performed to quantify the skeletal and dentoalveolar components in molar relationship and overjet correction. Compare the differences of cephalometric data and Johnston-analysis data.

RESULTS

The treatment changes showed significant differences in SNB, FH-NP, NA-PA, Co-Go, Co-Pog, ANB, lower facial height ratio, U1-PP, U6-PP, L1-MP and U1-L1. All the appliances improved overjet relationships significantly (Vanbeek, Herbst, Twin-Block and MA were 2.77 mm, 5.53 mm, 4.73 mm and 3.66 mm respectively) with significant retraction of maxillary incisors. The lower incisor displacement of group V and MA was negative, while that of group H and TB was positive and there were significant differences. Molar relationships were also improved by 3.45 mm, 6.85 mm, 3.48 mm and 0.92 mm for Vanbeek, Herbst, Twin-Block and MA. Mandible displacement showed a trend of group H > TB > V > MA. The displacement of maxillary molars in group H was greater than that in group C, TB and MA, and that of mandibular ones was greater than that in group C, V and MA, significantly. Herbst, Twin-Block and MA have more significant dentoalveolar effect than Vanbeek, while Vanbeek has more skeletal effect than the others especially in restraining maxillary growth.

CONCLUSIONS

Four appliances are all effective in mandibular advancement, modification of class II molar relationship and deep overjet, with unavoidable increase in lower facial ratio. Vanbeek Activator has the most skeletal effects. Vanbeek and MA have a good control of mandibular incisors while more compensatory lower incisors proclination in Herbst and Twin-Block. Herbst has greater maxillary molar distalization. MA allows aligning and leveling meanwhile leading the mandible forward.

Patient compliance with Twin Block appliance during treatment of Class II malocclusion: a randomized controlled trial on two check-up prescriptions

BACKGROUND

Compliance is crucial for the treatment outcome with removable appliances. Previous studies on treatment with the Twin Block appliance have focused on effectiveness in relation to other treatment methods or wear-time. Studies on different check-up intervals to improve compliance seem to be lacking.

OBJECTIVES

To compare the impact of two different check-up prescriptions on patient compliance and treatment outcome during treatment with Twin Block.

TRIAL DESIGN

Two-arm parallel group, single-centre, randomized controlled trial.

MATERIALS AND METHODS

Seventy-three patients, 38 boys, and 35 girls, mean age 11.2 years, were included and block-randomized into two groups treated with a Twin Block appliance. Group 1 was called for check-up visit every sixth week and group 2 every fourth week. Compliance was evaluated with a TheraMon® microsensor, moulded into the appliance, measuring wear-time. Overjet, overbite, and molar relationships were assessed on study casts before and after treatment. The treatment outcomes were analysed on an intention-to-treat basis.

RESULTS

In group 1, the reduction of overjet was 5.2 mm and the mean wear-time was 6.9 hours. In group 2, the reduction was 4.7 mm and the wear-time was 6.1 hours. Seventy-four per cent of the patients presented an overjet of 4 mm or less. Wear-time did not correlate to age, gender, or severity of malocclusion.

HARMS

No harm was observed in any patient. Lateral open bites were registered during treatment but were normalized at the end of the treatment.

LIMITATIONS

The trial was a single-centre study and long-term effects were not evaluated.

CONCLUSIONS

During treatment with the Twin Block appliance, a 4-week check-up interval did not improve treatment outcome or increase wear-time, compared to a 6-week check-up interval. The mean wear-time was 6.5 hours per day, even if the recommendation was 12 hours.

CLINICAL TRIAL REGISTRATION

NCT05155774.

[Long-term stability and relapse of deep bite correction: a systematic review]

INTRODUCTION

 Deep overbite is one of the most common malocclusions and is the most difficult to treat successfully. The real challenge remains the stability of long-term deep overbite correction. A search through the scientific literature revealed only one systematic review on this subject. Given the recent publications on the stability of deep bite correction and the development of new processes designed to avoid relapse of these treatments, this one existing systematic review needs to be updated. The purpose of the present systematic review is to evaluate the long-term stability of deep overbite correction.

MATERIALS AND METHODS

 Electronic databases were searched and nonelectronic journals were manually explored for papers on long-term stability and relapse of deep overbite correction. Articles deemed appropriate for inclusion in this review were selected and analyzed. Their scientific quality was assessed and the data they contained were extracted and summarized.

RESULTS

 The rate of deep overbite relapse was 47.27%. Patients treated with the straight wire appliance showed a 67.74% relapse rate whereas those treated with the Ricketts biological progressive segmented mechanics appliance displayed a 30.38% rate. Subjects treated towards the end of adolescence presented a 14.3% rate of deep overbite relapse whereas those treated in their early teens or in adulthood had a deep overbite relapse rate of 30% and 30.8%, respectively. Intramuscular injections of botox helped obtain 100% stability in maxillofacial surgery to correct deep bite.

CONCLUSION

 Age at initiation of treatment and treatment technique are two factors impacting the long-term stability of deep overbite correction.

A cephalometric study of the skeletal and dento-alveolar effects of the modified Louisiana State University activator in Class II malocclusion

Objectives

To analyse the skeletal and dento-alveolar effects of the modified Louisiana State University activator (MLSUA) in Class II treatment.

Materials and methods

A test group of 46 participants (25 females, 21 males) with Class II malocclusion treated with MLSUA followed by fixed appliances was compared with a matched Class II control group. Lateral cephalograms were taken at T1 (initial records), T2 (completion of MLSUA treatment), and T3 (before deband). The participants were also divided into two groups: pre-pubertal and pubertal according to skeletal maturity and three groups of different vertical facial patterns at the start of the treatment: brachyfacial, mesofacial, and dolichofacial. Statistical comparisons were performed with t-tests and analysis of variance (ANOVA).

Results

Statistically significant supplementary mandibular growth (Co-Gn) in the test group (2.6 mm) was associated with improvement of overjet (OJ), overbite (OB), and molar relationship. Short-term mandibular growth was greater in pubertal than pre-pubertal groups (2.4 mm, P < 0.05). Mandibular incisors retroclined by 2.1 degrees after MLSUA treatment. The brachyfacial group showed greater reduction in the ANB angle and forward movement of pogonion. Mandibular, palatal, and occlusal plane angles showed insignificant change regardless of the facial type.

Conclusions

MLSUA treatment corrected the Class II malocclusion by accelerating mandibular growth in the short-term with minimal dento-alveolar compensation, and the correction was maintained before deband. The treatment may be more effective if started at puberty. The mandibular, palatal, and occlusal planes remained stable throughout the treatment. Brachyfacial patients showed more favourable horizontal growth.

Comparison of Activator-Headgear and Twin Block Treatment Approaches in Class II Division 1 Malocclusion

The purpose was to compare the treatment effects of functional appliances activator-headgear (AH) and Twin Block (TB) on skeletal, dental, and soft-tissue structures in class II division 1 malocclusion with normal growth changes in untreated subjects. The sample included 50 subjects (56% females) aged 8–13 years with class II division 1 malocclusion treated with either AH (n = 25) or TB (n = 25) appliances. Pre- and posttreatment lateral cephalograms were evaluated and compared to 50 untreated class II division 1 cases matched by age, gender, ANB angle, and skeletal maturity. A paired sample, independent samples tests and discriminant analysis were performed for intra- and intergroup analysis. Treatment with both appliances resulted in significant reduction of skeletal and soft-tissue facial convexity, the overjet, and the prominence of the upper lip in comparison to untreated individuals (p < 0.001). Retroclination of maxillary incisors and proclination of mandibular incisors were seen, the latter being significantly more evident in the TB group (p < 0.05). Increase of effective mandibular length was more pronounced in the TB group. In conclusion, both AH and TB appliances contributed successfully to the correction of class II division 1 malocclusion when compared to the untreated subjects with predominantly dentoalveolar changes.