Alignment stability in Class II malocclusion treated with 2- and 4-premolar extraction protocols

Long-term relapse of anterior teeth in orthodontic patients treated with and without premolar extractions using a 3-dimensional surface mesh analysis

INTRODUCTION

The study evaluated the long-term postretention changes in patients with borderline crowding treated with and without premolar extractions using 3-dimensional surface registration analyses and 2-dimensional (2D) conventional measurements.

METHODS

The study sample comprised 29 nonextraction patients (nonextraction group [NG]) and 33 extractions (extraction group [EG]). Cephalometric radiographs and dental models of the included patients were used from pretreatment, posttreatment, and postretention. Retention durations were 3.76 ± 1.26 years and 4.52 ± 1.94 years in the NG and EG, respectively. The postretention follow-up period was 17.06 ± 5.83 years for the EG and 14.30 ± 5.70 years for the NG, with similar long-term observations. Maxillary and mandibular superimpositions were performed using 3-dimensional digital scans of the dental models and commercial software. In addition, conventional 2D model measurements and the irregularity index were also assessed.

RESULTS

The investigated parameters regarding the surface changes showed nonsignificant differences (P >0.05) between the 2 groups in the maxillary and mandibular anterior 6 teeth, except for the under tolerance value (the percentage of mesh points that is less than the lower tolerance limit) in mandibular surface registrations (P <0.044). In both groups, the maxillary and mandibular irregularity index and maxillary and mandibular intercanine distances showed significant relapses (P <0.05).

CONCLUSIONS

Comparable surface change outcomes were observed in the NGs and EGs. However, the percentage of meshes exceeding the negative threshold value (-1 mm) of the mandibular dentition in the NG exceeded the EG, indicating more significant lingual movement and relapse of the incisors. In addition, the 2D conventional linear relapse measurements were well below the 3.5 mm threshold value reported in the literature. This finding indicated that both treatment approaches provide acceptable long-term stability in borderline patients when similar retention regimens are employed.

Comparison of 1-year follow-up results of Forsus, headgear, and extraction treatment in Class II malocclusion

INTRODUCTION

This cross-sectional case-control observational study aimed to use lateral cephalometric radiographs to examine the 1-year follow-up results of 3 different treatment methods during Class II correction.

METHODS

The authors evaluated the lateral cephalometric records of patients treated with the Forsus fatigue-resistant device (group 1, n = 28), cervical headgears (CHG; group 2, n = 28), and maxillary first premolar extraction with fixed orthodontic appliances (group 3, n = 28). Each group was followed at pretreatment, posttreatment, and 1-year posttreatment. The data obtained were analyzed using the 1-way analysis of variance and Kruskal-Wallis methods.

RESULTS

At posttreatment, the ANB angle decreased significantly (P = 0.001) in the CHG group compared with the Forsus and extraction groups. The lower and upper facial heights of the CHG group were significantly increased (P <0.001) at posttreatment compared with the other groups. The mandibular incisor protrusion in the Forsus group was significantly higher (P = 0.005) than in the extraction patients, and extrusion of the mandibular incisors was significantly higher (P = 0.002) in the CHG group than in the Forsus group at posttreatment.

CONCLUSIONS

All 3 methods were effective in correcting Class II malocclusion, mainly at the dentoalveolar level, but some amount of relapses occurred after 1-year of follow-up. Distance of mandibular incisors and the mandibular plane changed significantly, increasing in CHG and extraction groups after 1-year of follow-up.

Comparison of dentoskeletal and soft tissue effects of Class II malocclusion treatment with Jones Jig appliance and with maxillary first premolar extractions

Objective:

The aim of this study was to compare the cephalometric changes in Class II division 1 malocclusion patients treated with Jones Jig appliance or with maxillary first premolar extractions.

Methods:

The sample consisted of 88 lateral cephalograms of 44 patients, divided into two groups. Group 1 consisted of 21 patients treated with Jones Jig appliance, with a mean initial age of 12.88 ± 1.23 years and final mean age of 17.18 ± 1.37 years, and a mean treatment time of 4.29 years. Group 2 comprised 23 patients treated with maxillary first premolar extractions, with a mean initial age of 13.59 ± 1.91 years and mean final age of 16.39 ± 1.97 years, and a mean treatment time of 2.8 years. Intergroup treatment changes were compared with t and Mann-Whitney tests.

Results:

Class II correction in G2 (maxillary first premolar extractions) presented significantly greater maxillary retrusion, reduction of anteroposterior apical base discrepancy, smaller increase in the lower anterior face height and significantly greater overjet reduction than G1 (Jones Jig).

Conclusions:

Treatment with maxillary first premolar extractions produced greater overjet reduction, but the two treatment protocols produced similar changes in the soft tissue profile.

Mandibular alignment changes after full-fixed orthodontic treatment: a systematic review and meta-analysis

Background

Although post-treatment mandibular alignment has been extensively investigated, the findings remain controversial.

Objectives

The objective was to assess mandibular alignment changes, as measured by the irregularity index, of patients who underwent full-fixed orthodontic treatment and were followed up at least 1 year after retention.

Search methods

MEDLINE, EMBASE, and Cochrane library, in addition, the reference lists of included studies, were screened. The search was conducted up to April 2018.

Selection criteria

The study designs included both interventional and observational studies of orthodontic patients who received either extraction or non-extraction treatment.

Data collection and analysis

The interventional studies were assessed using the Cochrane Collaboration’s risk of bias assessment tool. The quality of the observational studies was evaluated using National Institution of Health quality assessment tools. The first two authors independently applied the eligibility criteria, extracted the data, and assessed the risk of bias. Any conflicts were resolved with consensus discussion with the third author.

Results

The search retrieved 11 326 articles, 170 of which were assessed for eligibility. There were 44 studies included in the qualitative assessments and 30 in the meta-analyses. The studies included 1 randomized control trial (RCT) and 43 observational studies. The RCT was judged to have a high risk of bias and all of the observational studies had either fair or poor quality. The meta-analysis was based on studies judged to be of fair quality, including a total of 1859 patients. All meta-analyses were performed using random-effect models. The standardized mean difference between post-treatment and post-retention irregularity was 1.22 (95% CI, 1.04–1.40) and 0.85 (95% CI, 0.63–1.07) after extraction and non-extraction treatments, respectively. There was a substantial heterogeneity for the extraction (I2 = 75.2%) and non-extraction (I2 = 70.1%) studies. The follow-up duration (1–10 versus 10–20 years) explained 33% of the heterogeneity, with longer follow-up studies showing more irregularity.

Limitations

The quality of evidence provided by the studies was low. There was a risk of publication bias, and the search was limited to English language.

Conclusions and implications

Post-treatment mandibular irregularity increases are limited. Irregularity increases are slightly greater in patients treated with mandibular premolars extractions, and in patients followed up over longer periods of time.

Registration

The study protocol was not registered.

Changes in apical base sagittal relationship in Class II malocclusion treatment with and without premolar extractions: A systematic review and meta-analysis

OBJECTIVE

To evaluate the changes in apical base sagittal relationship in Class II treatment with and without premolar extractions.

MATERIALS AND METHODS

Controlled studies evaluating ANB angle changes after Class II Division 1 malocclusion treatment with or without premolar extractions were considered. Electronic databases (PubMed, Embase, Web of Science, Scopus, The Cochrane Library, Lilacs, and Google Scholar) without limitations regarding publication year or language were searched. Risk of bias was assessed with Risk Of Bias in Non-randomized Studies-of Interventions tool of the Cochrane Collaboration. Mean difference (MD) and 95% confidence interval (CI) were calculated from the random-effects meta-analysis. Subgroup and sensitivity analyses were also performed.

RESULTS

Twenty-five studies satisfied the inclusion criteria and were included in the qualitative synthesis. Eleven nonextraction and only one extraction Class II treatment studies presented untreated Class II control group. Therefore, meta-analysis was performed only for the nonextraction protocol. In treated Class II nonextraction patients, the average of the various effects was a reduction in the ANB angle of 1.56° (95% CI: 1.03, 2.09, P < .001) compared with untreated Class II subjects. Class II malocclusions treated with two maxillary-premolar extractions and four-premolar extractions produced estimated mean reductions in ANB of -1.88° and -2.55°, respectively. However, there is a lack of low-risk-of-bias studies.

CONCLUSIONS

According to the existing low quality evidence, the apical base sagittal relationship in nonextraction, two-maxillary and four-premolar extractions Class II treatments decreases -1.56°, 1.88° and 2.55°, respectively. Further studies are necessary to obtain more robust information.

Canine retraction: A systematic review of different methods used

Canine retraction is a very important step in treatment of patients with crowding, or first premolar extraction cases. In severe crowding cases until, the canines have been distilized to relive the crowding, space to correctly align the incisors will not be available. Correct positioning of the canines after retraction is of great importance for the function, stability, and esthetics. The aim of this systematic review was to examine, in an evidence-based way, which kinds of canine retraction methods/techniques are most effective and which have the least side effects. A literature survey was performed by applying the Medline Database (Entrez PubMed) and Science Direct database covering the period from 1985 to 2014, to find out efficient ways to accomplish canine retraction. Randomized controlled trials (RCTs), prospective and retrospective controlled studies, and clinical trials were included. Two reviewers selected and extracted the data independently and assessed the quality of the retrieved studies. The search strategy resulted in 324 articles, of which 22 met the inclusion criteria. Due to the vast heterogeneity in study methods, the scientific evidence was too weak to evaluate retraction efficiency during space closure. The data so far reviewed proved that elastomeric power chains, elastic threads, magnets, NiTi coil springs, corticotomies, distraction osteogenesis, and laser therapy, all are able to provide optimum rate of tooth movements. All the methods were nearly similar to each other for retraction of canines Most of the techniques lead to anchorage loss in various amounts depending on the methods used. Most of the studies had serious problems with small sample size, confounding factors, lack of method error analysis, and no blinding in measurements. To obtain reliable scientific evidence, controlled RCT's with sufficient sample sizes are needed to determine which method/technique is the most effective in the respective retraction situation. Further studies should also consider patient acceptance and cost analysis as well as implants and minor surgeries for canine retraction.

Stability and relapse of maxillary anterior crowding treatment in class I and class II Division 1 malocclusions

INTRODUCTION

The maxillary anterior teeth are the most important to facial esthetics because they are the first to show on a smile. Therefore, stability of the maxillary anterior teeth alignment is an important issue. The objective of this study was to compare the stability of maxillary anterior tooth alignment in Class I and Class II Division 1 malocclusions.

METHODS

The sample comprised dental casts of 70 patients with Class I and Class II Division 1 malocclusions and a minimum of 3 mm of maxillary anterior crowding measured by an irregularity index. The patients were treated with extractions and evaluated at pretreatment and posttreatment and at least 5 years after treatment. The sample was divided into 3 groups: group 1, Class I malocclusion treated with 4 first premolar extractions comprising 30 subjects, with an initial age of 13.16 years and 8.59 mm of initial maxillary irregularity; group 2, Class II malocclusion treated with 4 first premolar extractions comprising 20 subjects, with an initial age of 12.95 years and 11.10 mm of maxillary irregularity; and group 3, Class II malocclusion treated with 2 first maxillary premolar extractions comprising 20 subjects, with an initial age of 13.09 years and 9.68 mm of maxillary irregularity.

RESULTS

The decrease in the maxillary irregularity index was significantly greater in group 2 than in group 1 during treatment. The stability of maxillary anterior alignment was 88.12% over the long term; 77% of the linear displacement of the anatomic contact points tended to return to their original positions.

CONCLUSIONS

Stability of maxillary anterior alignment between the 3 groups was similar. The stability of maxillary anterior alignment was high over the long term, but a high percentage of teeth tended to return to their original positions.

Prevalência de maloclusão e sua associação com alterações funcionais do sistema estomatognático entre escolares

Esta pesquisa objetivou estimar a prevalência de maloclusões entre escolares com 12 anos de idade do Município de Camaragibe, Pernambuco, Brasil. As maloclusões foram estratificadas em função do grau de severidade, analisando-se, ainda, a sua associação com as alterações das seguintes funções: fonoarticulação, respiração e deglutição. A oclusão foi avaliada por intermédio do Treatment Priotiy Index (TPI) e as referidas funções por meio de critérios utilizados na rotina clínica fonoaudiológica por um único examinador calibrado (valores de kappa variáveis entre 0,64 e 1,00). Os escolares foram selecionados randomicamente em 11 escolas públicas. Dos 173 sorteados, 82,1% apresentaram maloclusão (IC95%: 76,4-87,8), sendo 38,2% consideradas manifestações menores de maloclusões; 20,8% maloclusões definidas; 13,3% maloclusões severas; e 9,8% maloclusões muito severas. Conclui-se que há uma alta demanda reprimida por tratamentos ortodônticos e que quanto maior a severidade das maloclusões maior é a possibilidade de associação com alterações funcionais, fato que deve ser levado em consideração no planejamento de serviços públicos destinados aos referidos agravos.