Stability of early anterior open bite treatment: a 2-year follow-up randomized clinical trial

A longitudinal study of the probability of developing malocclusion in children using a Bayesian analysis

INTRODUCTION

This study evaluated the probability of developing malocclusions in mixed dentition.

METHODS

A longitudinal study was conducted with 598 children (aged 5 years) in deciduous dentition. The children were followed for 3 years until mixed dentition (aged 8 years). Overjet, overbite, and transversal relations were evaluated. Bayesian models were used to analyze the data and estimate the parameters.

RESULTS

The parameter θ was used for the distributions, indicating the probability of presenting a given condition with a credibility index (ICr) of 95%. After 3 years of follow-up, 121 children were reevaluated. The results showed that children have a high probability of malocclusion in mixed dentition. There was a higher probability of developing an increased overjet in the mixed dentition of 20.5% (ICr 95%, 13.6-28.4) to 48.3% (ICr 95%, 39.1-57.7) and a higher probability of having a normal overbite in the deciduous dentition and a lower probability in the mixed dentition (ICr 95%, 9.2-21.3).

CONCLUSIONS

Considering the probabilistic model of Bayesian analysis, children with normal overjet in the deciduous dentition may show an increased overjet in the mixed dentition. Concerning overbite, children may present an anterior open bite during the transition between deciduous and mixed dentition, as well as self-correction of deep overbite in mixed dentition. Furthermore, they may present a posterior crossbite during the mixed dentition when there is a normal transverse relationship in the deciduous dentition.

Preclinical in vitro study of streptococcus mutans accumulation in three fixed retainer designs: Microbiological assay

The use of fixed retainers in the lower arch is frequent; however, its presence increases the accumulation of biofilm and dental calculus. The objective of this research was to evaluate, in vitro, the accumulation of Streptococcus mutans (S. mutans) in 3 designs of fixed retainers. Nine models were reproduced in heat-cured acrylic resin and divided into groups: straight retainer (SR), retainer with vertical strap (RVS), retainer with horizontal strap (RHS). The accumulation of S. mutans was assessed using the MTT assay (3-4,5-dimethyl-thiazol-2-yl-2,5-diphenyltetrazolium bromide) and then measured using an automated reader. The RHS group showed less biofilm accumulation compared to the other groups (p<0.05). The distance between the tooth surface and the retainer showed a strong negative correlation with biofilm accumulation (rs=-0.79, p=0.00037). The RHS showed significantly less accumulation of S. mutans due to the distance between the retainer and the tooth surface. This research provides relevant data for a future randomized clinical trial.

Effects of bonded spurs, fixed and removable palatal crib in the early treatment of anterior open bite: A systematic review and meta-analysis

INTRODUCTION

Bonded spurs, fixed or removable palatal cribs have been used to treat anterior open bite (AOB) in growing children. Different conclusions have been brought out by different authors. This meta-analysis aimed to evaluate the effect of bonded spurs, fixed and removable palatal cribs in the early treatment of AOB.

METHODS

A comprehensive electronic search was carried out through PubMed, Embase (via Ovid), MEDLINE (via Ovid), Cochrane Central Register of Controlled Trials, and Web of Science up to May 1, 2022. This meta-analysis was performed in accordance with the Cochrane Handbook for Systematic Reviews of Interventions. The work was carried out by 2 reviewers in duplicate and independently, including electronic searching, data extracting, risk of bias assessment, quality of evidence grading, heterogeneity and statistical power analysis, and eligibility evaluation of the retrieved articles.

RESULTS

Four studies out of 181 articles were recruited in the meta-analysis after applying the inclusion and exclusion criteria. The results showed that bonded lingual spurs and fixed palatal crib or spurs produced similar overbite changes (mean difference, -0.32; 95% confidence interval, -1.06 to 0.43; P = 0.41; I2 = 27%; meta power = 0.099). Fixed palatal crib and removable palatal crib also exhibited comparable effects in correcting AOB (mean difference, -0.02; 95% confidence interval, -0.90 to 0.86; P = 0.96; I2 = 0%; meta power = 0.2182). The quality of evidence about these 2 outcomes assessed with GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) was low.

CONCLUSIONS

Bonded lingual spurs, fixed palatal crib or spurs, and removable palatal crib had similar effects in the early treatment of AOB. Because the number of included studies was limited and only the overbite changes before and after treatment were assessed, more clinical randomized controlled studies with longer follow-ups are needed to get more clinically significant advice.

Influence of rapid maxillary expansion in the stability of anterior open bite treatment

OBJECTIVES

This study aimed to compare the stability of anterior open bite (AOB) in patients treated with and without rapid maxillary expansion (RME) before fixed palatal crib (PC) therapy in the mixed dentition.

MATERIAL AND METHODS

Expansion/palatal crib group (EPC) was comprised of 25 patients (10 male, 15 female, mean initial age of 7.8 years) with AOB treated with RME before PC therapy. Palatal crib group (PC) included 25 patients with AOB (10 male, 15 female, mean initial age of 8.0 years) treated only with PC therapy. Lateral cephalograms were analyzed at pre-treatment (T0), after PC therapy (T1), and 3 years after PC removal (T2) in both groups. AOB relapse was considered when a negative overbite was observed at T2. Intergroup comparisons of interphase changes were performed using t and Mann-Whitney tests (p < 0.05).

RESULTS

Treatment and post-treatment alterations showed similar changes in both groups for all cephalometric variables. Overall changes from T0 to T2 were similar between the groups except for the maxillary incisors that tipped lingually in PC group (1.PP =  - 3.37°) and labially in EPC group (1.PP = 1.76°). The frequency of AOB relapse was 8% and 4% in the EPC and PC groups, respectively. Treatment time in the EPC group (9.7 months) was shorter (p = 0.024) when compared to the PC group (11.0 months).

CONCLUSIONS

In the mixed dentition, stability of AOB treated with RME before fixed PC therapy was similar to PC therapy alone. However, treatment time with fixed PC was slightly shorter in the group treated with RME.

CLINICAL RELEVANCE

This study aims to understand if RME performed previously to fixed palatal crib contributes to the index of stability of AOB treatment in the mixed dentition.