Overjet, overbite, and anterior crowding relapses in extraction and nonextraction patients, and their correlations.

INTRODUCTION: In this study, we aimed to compare the relapse of maxillary and mandibular anterior crowding, overjet, and overbite 5 years after treatment in subjects with Class I and Class II malocclusions treated with and without extractions, and also to evaluate the correlations among these factors. METHODS: The sample comprised 84 subjects with Class I and Class II malocclusions, treated with and without extractions. Group 1 comprised 44 subjects with an initial mean age of 12.96 years treated without extractions. Group 2 included 40 subjects with an initial mean age of 13.01 years treated with 4 premolar extractions. Data were obtained from dental casts at the pretreatment, posttreatment, and long-term posttreatment stages. Intergroup comparisons were performed with t tests. To verify the correlations among the relapse of overjet, overbite, and anterior crowding, the Pearson correlation test was used. RESULTS: Maxillary incisor irregularity and its relapse in the nonextraction group were significantly greater at the long-term posttreatment stage and the long-term posttreatment period, respectively. Long-term postreatment overjet changes were similar in the groups. Overbite and its relapse were significantly greater in the extraction group in the long-term posttreatment stage and period, respectively. There was a positive correlation of the relapse of mandibular incisor crowding with the relapse of overjet and overbite, and also a correlation of overjet and overbite relapses. CONCLUSIONS: There was greater maxillary crowding relapse in the nonextraction group and greater overbite relapse in the extraction group. There were significant and positive correlations of overjet and overbite relapses with mandibular anterior crowding relapse and consequently between overjet and overbite relapses.

Comparative cephalometric study of the airways between different ethnic groups with normal occlusion.

OBJECTIVE: This study aimed to compare the nasopharynx and oropharynx airway dimensions of Caucasians, Blacks, Japanese, Japanese Brazilians, and Black Caucasians. METHODS: A sample of 216 lateral radiographs of untreated young Brazilian subjects (mean age of 12.94 years; SD 0.88) were divided into five groups: Black Caucasian, Black, Caucasian, Japanese, and Japanese Brazilian. Lateral radiographs were used to measure the oropharynx (from the midpoint on the soft palate to the closest point on the anterior pharyngeal wall) and the nasopharynx (from the intersection of the posterior border of the tongue and the inferior border of the mandible to the closest point on the posterior pharyngeal wall). Analyses of variance (ANOVA) and Tukey's test were performed (p< 0.05). RESULTS: The linear dimension of the oropharynx was similar among the different ethnic groups. Caucasian individuals presented a significantly greater linear dimension of the nasopharynx than Black Caucasian and Black individuals. CONCLUSIONS: All the groups had similar buccopharyngeal values. However, Caucasian individuals had significantly higher values when compared to Black Caucasians and Black individuals.

Correction of Class II malocclusion with Class II elastics: a systematic review.

INTRODUCTION: Although Class II elastics have been widely used in the correction of Class II malocclusions, there is still a belief that their side effects override the intended objectives. The aim of this systematic review was to evaluate the true effects of Class II elastics in Class II malocclusion treatment. METHODS: A search was performed on PubMed, Scopus, Web of Science, Embase, Medline, and Cochrane databases, complemented by a hand search. Study eligibility criteria were the application of Class II elastics in Class II malocclusion treatment and the presentation of dental or skeletal outcomes of treatment. All age groups were included. RESULTS: The search identified 417 articles, of which 11 fulfilled the inclusion criteria. Four studied the isolated effects of Class II elastics, and 7 were comparisons between a single use of elastics and another method for Class II malocclusion correction. Because of the differences in treatment modalities in these articles, a meta-analysis was not possible. CONCLUSIONS: Based on the current literature, we can state that Class II elastics are effective in correcting Class II malocclusions, and their effects are primarily dentoalveolar. Therefore, they are similar to the effects of fixed functional appliances in the long term, placing these 2 methods close to each other when evaluating treatment effectiveness. Little attention has been given to the effects of Class II elastics on the soft tissues in Class II malocclusion treatment.

Periodontal status of maxillary central incisors after orthodontic traction: a longitudinal follow-up.

BACKGROUND: The aim of this study was to evaluate the clinical and radiographic periodontal status of impacted permanent maxillary central incisors (Mx.1) after a long term of orthodontic traction. METHODOLOGY: This split-mouth study evaluated a sample of 11 patients (five females, six males) treated with Mx.1 unilateral traction one to 28 years after the removal of orthodontic appliances. The traction Group (TG) consisted of 11 Mx.1 and the Comparison Group (CG) comprised 11 spontaneously erupted contralateral Mx.1. High-resolution CBCT exams of central incisors were performed using Accuitomo (J. Morita, Kyoto, Japan). Cross-section imagens passing through the center of maxillary central incisors were used to measure buccal and lingual alveolar bone level. Presence of fenestration, root dilacerations, root coverage, and position of the root apex were also assessed in the same images. Clinical parameters included periodontal probing depth, attachment level, gingival bleeding index, plaque index, degree of gingival recession, amount of gingival mucosa, and evaluation of interproximal papilla and black triangle. Digital model analysis included an assessment of clinical crown height and width. Intergroup comparisons were performed using paired t-, McNemar's, and Wilcoxon tests (p<0.05). RESULTS: Compared to CG, we found a significantly thinner labial bone plate thickness in TG at the middle (p=0.000) and apical (p=0.009) root level. We also observed an apical displaced labial bone crest level in TG (p=0.000). The Traction Group showed a greater frequency of root dilacerations and gingival recessions, a decreased amount of keratinized mucosa, and a decreased clinical attachment level at the labial aspect compared to contralateral teeth. CONCLUSIONS: A decreased thickness and height of labial alveolar bone and gingival recessions were found in maxillary central incisors 15 years after orthodontic traction. Though incisor traction might cause some periodontal impact, differences are acceptable under a clinical point of view considering the cost-benefit ratio.

Factors affecting the stability of maxillary extraction site closure.

INTRODUCTION: A side effect observed in cases treated with extractions is the instability of orthodontic space closure. OBJECTIVE: The aim of this study was to investigate the influence of gingival invagination, presence of third molars and facial pattern, on the stability of orthodontic space-closure in the maxillary arch. METHODS: Ninety-nine subjects (41 male and 58 female) with Class I malocclusion treated with four premolars extraction were evaluated. Extraction sites reopening and gingival invaginations were evaluated in scanned dental models in the posttreatment and 1-year posttreatment stages (mean age 16.1 years). Third molars presence was evaluated at 1-year posttreatment panoramic radiographs, and the facial pattern (SN.GoGn) was evaluated in the initial lateral headfilms. Multiple logistic regression analysis was used to estimate the influence of the aforementioned independent variables on the frequency of extraction space reopening. RESULTS: Space reopening was observed in 20.20% of the subjects 1-year post-debonding. Gingival invaginations were present in 25.73% of quadrants after debonding and in 22.80% 1-year posttreatment. The mean pre-treatment SN.GoGn was 35.64 degrees (SD=5.26). No significant influence was observed of the three independent variables on the instability of extraction site closure. CONCLUSIONS: The presence of gingival invaginations, third molars and facial growth pattern do not seem to influence maxillary extraction sites reopening.

The influence of 3x3 bonded retainer on anterior crowding relapse in mandibular incisor extraction cases.

OBJECTIVE: To evaluate the 3x3 bonded retainer influence on the mandibular anterior crowding in cases treated with mandibular incisor extraction. METHODS: The sample comprised pretreatment, posttreatment and follow-up orthodontic records of 16 subjects (10 females and 6 males) with Class I malocclusion treated with extraction of a single mandibular incisor. The mean ages (± SD) at pretreatment, posttreatment and follow-up evaluation were 23.45 ± 9.14 years, 25.50 ± 8.95 years and 30.11 ± 8.59 years, respectively. The mean (± SD) treatment time and posttreatment evaluation time were 2.05 ± 0.45 years and 4.60 ± 1.85 years , respectively. Little irregularity index and interdental widths were evaluated using dental casts. The sample was divided into two subgroups, according to the presence of the 3x3 bonded retainer at follow-up. RESULTS: The subgroup without 3x3 bonded retainer presented a greater relapse at the follow-up, when compared to 3x3 bonded retainer subgroup. CONCLUSION: There was a significant relapse in cases treated with mandibular incisor extraction at follow-up. The subgroup without 3x3 bonded retainer showed a significant relapse at the follow-up when compared to the retainer group.

Evaluation of Mandibular First Molars' Axial Inclination and Alveolar Morphology in Different Facial Patterns: A CBCT Study.

OBJECTIVE: The purpose of this study was to evaluate and compare the axial inclination of the mandibular first molars and their respective bone morphology among individuals with different facial patterns. MATERIALS AND METHODS: The sample comprised the cone beam computed tomographies (CBCTs) of 58 subjects divided into three groups according to the facial patterns: 18 brachyfacial (Group 1), with a mean age of 21.58 years; 23 mesofacial (Group 2), with a mean age of 19.14 years; and 17 dolichofacial subjects (Group 3), with a mean age of 19.09 years. Eight variables were evaluated on CBCT scans of each subject: buccal and lingual mandibular height, cervical and middle mandibular width, inclination of mandibular body, inclination of the mandibular molar buccal surface, molar width, molar angulation and tooth/bone angle. Intergroup comparisons were performed with one-way analysis of variance followed by Tukey tests. RESULTS: Buccal mandibular height presented statistically significant difference in the three facial patterns. Lingual mandibular height and mandibular inclination showed to be statistically and significantly smaller in brachyfacial subjects than in the other two groups. Mandibular width presented a statistically significant difference between brachyfacial and mesofacial groups. Negative correlations could be observed between the facial pattern and the buccal and lingual mandibular heights and inclination of the mandibular body. CONCLUSION: Buccal mandibular height was significantly and progressively larger in brachyfacial, mesofacial, and dolichofacial subjects. Lingual mandibular height was significantly smaller in brachyfacial than in mesofacial and dolichofacial subjects. Mandibular width was significantly thicker in brachyfacial than in mesofacial subjects. Brachyfacial subjects had smaller mandibular inclination than mesofacial and dolichofacial subjects.

Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study.

OBJECTIVE: To retrospectively compare the dentoskeletal and soft tissue changes of patients with Class II malocclusion treated with cervical headgear and Jones Jig appliances, followed by fixed appliances. MATERIAL AND METHODS: The sample comprised 46 Class II malocclusion patients divided into two groups. Patients with Class II malocclusion based on the ANB angle and plaster model analyses, needing non-extraction orthodontic treatment, absence of mandibular crowding and no previous orthodontic treatment were eligible to be selected. Group 1 consisted of 25 patients treated with cervical headgear (CH) followed by fixed appliances for a mean period of 3.26 years and group 2 consisted of 21 patients treated with the Jones Jig (JJ) appliance for a mean of 4.29 years. Lateral cephalograms were evaluated at the beginning and at the end of orthodontic treatment. For intergroup comparisons, t and Mann-Whitney tests were performed. RESULTS: The cervical headgear group produced significantly greater maxillary anterior displacement restriction (SNA; CH: -0.97°±1.33; JJ: 0.07°±1.73; P=0.025), apical base discrepancy improvement (ANB; CH: -1.52°±1.25; JJ: 0.36°±1.46; P=0.006), FMA reduction (CH: -0.78°±2.68; JJ: 1.07°±2.84; P=0.028) and distal mandibular molar angulation (Md6.PM; CH: 6.97°±3.66; JJ: 2.77°±6.87; P=0.013) than the Jones Jig group. CONCLUSIONS: Both distalizers followed by fixed appliances were effective to correct Class II malocclusion. The cervical headgear group presented skeletal effects with less treatment time and there were no significant intergroup differences regarding soft tissue changes.

Comparative cephalometric study of the airways between different ethnic groups with normal occlusion

ABSTRACT Objective: This study aimed to compare the nasopharynx and oropharynx airway dimensions of Caucasians, Blacks, Japanese, Japanese Brazilians, and Black Caucasians. Methods: A sample of 216 lateral radiographs of untreated young Brazilian subjects (mean age of 12.94 years; SD 0.88) were divided into five groups: Black Caucasian, Black, Caucasian, Japanese, and Japanese Brazilian. Lateral radiographs were used to measure the oropharynx (from the midpoint on the soft palate to the closest point on the anterior pharyngeal wall) and the nasopharynx (from the intersection of the posterior border of the tongue and the inferior border of the mandible to the closest point on the posterior pharyngeal wall). Analyses of variance (ANOVA) and Tukey's test were performed (p< 0.05). Results: The linear dimension of the oropharynx was similar among the different ethnic groups. Caucasian individuals presented a significantly greater linear dimension of the nasopharynx than Black Caucasian and Black individuals. Conclusions: All the groups had similar buccopharyngeal values. However, Caucasian individuals had significantly higher values when compared to Black Caucasians and Black individuals.

RESUMO Objetivo: Este estudo teve como objetivo comparar as dimensões das vias aéreas da nasofaringe e da bucofaringe de leucodermas, melanodermas, xantodermas, feodermas e nipo-brasileiros. Material e métodos: Uma amostra de 216 telerradiografias laterais de jovens brasileiros não tratados (idade média de 12,94 anos; DP 0,88) foi dividida em cinco grupos: melanodermas, leucodermas, xantodermas, feodermas e nipo-brasileiros. As telerradiografias foram utilizadas para medir a bucofaringe (do ponto médio do palato mole até o ponto mais próximo da parede anterior da faringe) e a nasofaringe (da intersecção da borda posterior da língua e da borda inferior da mandíbula até o ponto mais próximo). Foram realizadas análises de variância (ANOVA) e teste de Tukey (p < 0,05). Resultados: A dimensão linear da bucofaringe foi semelhante entre os diferentes grupos étnicos. Indivíduos leucodermas apresentaram dimensão linear da nasofaringe significativamente maior do que indivíduos feodermas e melanodermas. Conclusões: Todos os grupos apresentaram valores da bucofaringe semelhantes. No entanto, os indivíduos leucodermas apresentaram valores significantemente maiores, quando comparados aos feodermas e melanodermas.

Comparison of deflection forces of esthetic archwires combined with ceramic brackets.

Coated archwires and ceramic brackets have been developed to improve facial esthetics during orthodontic treatment. However, their mechanical behavior has been shown to be different from metallic archwires and brackets. Therefore, the aim of this study was to compare the deflection forces in coated nickel-titanium (NiTi) and esthetic archwires combined with ceramic brackets. Material and Methods Non-coated NiTi (NC), rhodium coated NiTi (RC), teflon coated NiTi (TC), epoxy coated NiTi (EC), fiber-reinforced polymer (FRP), and the three different conventional brackets metal-insert polycrystalline ceramic (MI-PC), polycrystalline ceramic (PC) and monocrystalline ceramic (MC) were used. The specimens were set up on a clinical simulation device and evaluated in a Universal Testing Machine (Instron). An acrylic device, representative of the right maxillary central incisor was buccolingually activated and the unloading forces generated were recorded at 3, 2, 1 and 0.5 mm. The speed of the testing machine was 2 mm/min. ANOVA and Tukey tests were used to compare the different archwires and brackets. Results The brackets presented the following decreasing force ranking: monocrystalline, polycrystalline and polycrystalline metal-insert. The decreasing force ranking of the archwires was: rhodium coated NiTi (RC), non-coated NiTi (NC), teflon coated NiTi (TC), epoxy coated NiTi (EC) and fiber-reinforced polymer (FRP). At 3 mm of unloading the FRP archwire had a plastic deformation and produced an extremely low force in 2; 1 and 0.5 mm of unloading. Conclusion Combinations of the evaluated archwires and brackets will produce a force ranking proportional to the combination of their individual force rankings.

Evaluation of the attractiveness of different gingival zeniths in smile esthetics.

OBJECTIVE: To evaluate the smile attractiveness of different gingival zeniths by general dentists, orthodontists and laypersons and the esthetic perception in the symmetric and asymmetric changes in gingival zeniths. METHODS: Posed photographs of five patients were taken and digitally manipulated in Keynote software, in the gingival zenith region, in increments of 0.5 to 1mm in maxillary central and lateral incisors, symmetrically and asymmetrically, in nine different ways for each patient. The photos were then uploaded to a website, where evaluators (general dentists, orthodontists and laypersons) could observe and vote according to their esthetic perception, scoring from 1 to 10, 1 being the least attractive and 10 the more attractive. Kruskal-Wallis and Mann-Whitney tests were used for comparison. RESULTS: Asymmetric gingival zeniths were less attractive than symmetrical gingival zeniths; gingival zenith differences greater than 1mm were perceptible in the smile attractiveness, both by laypersons, general dentists and orthodontists. When comparing maxillary central incisors with maxillary lateral incisors, the aesthetic change performed in the central incisors are more perceptible than those performed in lateral incisors, both symmetrical and asymmetrical. In a general way, orthodontists and general dentists are more critical in the evaluation and perception of gingival zenith changes, with the laypersons perceiving this change only from 1mm of maxillary right central incisor asymmetrical change. CONCLUSIONS: Asymmetric gingival zeniths are less attractive than symmetrical ones. Gingival zenith differences greater than 1mm are perceptible in the smile attractiveness. Orthodontists and general dentists are more critical in evaluating smile esthetics.

Periodontal status of maxillary central incisors after orthodontic traction: a longitudinal follow-up

Abstract The aim of this study was to evaluate the clinical and radiographic periodontal status of impacted permanent maxillary central incisors (Mx.1) after a long term of orthodontic traction. Methodology This split-mouth study evaluated a sample of 11 patients (five females, six males) treated with Mx.1 unilateral traction one to 28 years after the removal of orthodontic appliances. The traction Group (TG) consisted of 11 Mx.1 and the Comparison Group (CG) comprised 11 spontaneously erupted contralateral Mx.1. High-resolution CBCT exams of central incisors were performed using Accuitomo (J. Morita, Kyoto, Japan). Cross-section imagens passing through the center of maxillary central incisors were used to measure buccal and lingual alveolar bone level. Presence of fenestration, root dilacerations, root coverage, and position of the root apex were also assessed in the same images. Clinical parameters included periodontal probing depth, attachment level, gingival bleeding index, plaque index, degree of gingival recession, amount of gingival mucosa, and evaluation of interproximal papilla and black triangle. Digital model analysis included an assessment of clinical crown height and width. Intergroup comparisons were performed using paired t-, McNemar's, and Wilcoxon tests (p<0.05). Results Compared to CG, we found a significantly thinner labial bone plate thickness in TG at the middle (p=0.000) and apical (p=0.009) root level. We also observed an apical displaced labial bone crest level in TG (p=0.000). The Traction Group showed a greater frequency of root dilacerations and gingival recessions, a decreased amount of keratinized mucosa, and a decreased clinical attachment level at the labial aspect compared to contralateral teeth. Conclusions A decreased thickness and height of labial alveolar bone and gingival recessions were found in maxillary central incisors 15 years after orthodontic traction. Though incisor traction might cause some periodontal impact, differences are acceptable under a clinical point of view considering the cost-benefit ratio.

Evaluation of asymmetries between subjects with Class II subdivision and apparent facial asymmetry and those with normal occlusion.

INTRODUCTION: The objective of this study was to compare the degree of skeletal asymmetry between subjects with Class II subdivision malocclusion and apparent facial asymmetry and subjects with normal occlusion. METHODS: The sample consisted of 23 subjects with Angle Class II subdivision malocclusions and apparent facial asymmetry (mean age, 15.78 years) and 30 subjects with normal occlusions (mean age, 22.42 years). Each had all permanent teeth, including first molars. Radiographic asymmetry was assessed by measuring the relative difference in spatial position of dental and skeletal landmarks between right and left sides in both anteroposterior and transverse dimensions in the submentovertex and in the transverse and vertical dimensions in the posteroanterior radiographs. Independent t tests were used to compare radiographic asymmetries between groups. RESULTS: Despite the predominantly dentoalveolar nature of the asymmetries found in Class II subdivision malocclusions with apparent facial asymmetry, the radiographic mandibular asymmetry was small in relation to Class II subdivision malocclusions in general. The components that contributed to the asymmetric anteroposterior relationship in the Class II subdivision malocclusion with apparent facial asymmetry were mainly dentoalveolar. The primary contributor to the differences between the 2 groups was the distal positioning of the mandibular first molars on the Class II side. A secondary contributor was the mesial positioning of the maxillary first molars on the Class II side. As a consequence of the more frequent asymmetry in the lower third of face, the mandibular dental midline and the antegonial angle were deviated on the Class II side, as evaluated on the posteroanterior radiograph. CONCLUSIONS: The main component of Class II subdivision is dentoalveolar, primarily distal positioning of the first mandibular molar on the Class II side and secondarily mesial positioning of the first maxillary molar on the same side.

Correlation between mandibular incisor crown morphologic index and postretention stability.

INTRODUCTION: Considering postretention stability as a result of successful orthodontic treatment, we aimed to verify the influence of mandibular-incisor-crown morphology in the relapse of mandibular anterior crowding. METHODS: The sample comprised 56 white subjects of both sexes with Class I and Class II malocclusions at pretreatment, treated with extraction of 4 first premolars and edgewise mechanics. No patient underwent interproximal stripping during or after treatment. Mean pretreatment age was 13.23 years. Mean treatment time was 2.11 years, and mean posttreatment evaluation time was 5.12 years. Mandibular anterior crowding was measured with the Little irregularity index, and the mesiodistal and buccolingual proportion of the mandibular incisor crowns was measured with the Peck and Peck index. The measurements were obtained from dental casts at the pretreatment, posttreatment, and postretention stages. The Pearson correlation coefficient was calculated to determine the correlation between mandibular-incisor-crown morphology and the amount of postretention-crowding relapse. RESULTS: The mandibular-incisor-crown morphologic index was not significantly correlated with the amount of mandibular-anterior-crowding relapse. CONCLUSIONS: Mandibular-incisor-crown morphology is not correlated with the amount of mandibular-anterior-crowding relapse.

Orthodontic treatment time in 2- and 4-premolar-extraction protocols.

INTRODUCTION: The purpose of this study was to compare the treatment times of complete Class II malocclusions treated with 2- and 4-premolar-extraction protocols. METHODS: Ninety-seven patients were selected and divided into 2 groups, according to the 2 extraction criteria. Group 1, treated with 2 maxillary premolar extractions, consisted of 49 patients (30 male, 19 female) with a mean age of 14.35 years. Group 2, treated with 4 premolar extractions, consisted of 48 patients (27 male, 21 female) with a mean age of 13.03 years. Treatment times of the groups were compared with the t test. RESULTS: Treatment times were significantly shorter with the 2-premolar-extraction protocol compared with the 4-premolar-extraction protocol. CONCLUSIONS: Treatment time will be shorter and the occlusal results more predictable with a 2-premolar-extraction protocol compared with 4 premolar extractions.

Factors affecting the stability of maxillary extraction site closure

ABSTRACT Introduction: A side effect observed in cases treated with extractions is the instability of orthodontic space closure. Objective: The aim of this study was to investigate the influence of gingival invagination, presence of third molars and facial pattern, on the stability of orthodontic space-closure in the maxillary arch. Methods: Ninety-nine subjects (41 male and 58 female) with Class I malocclusion treated with four premolars extraction were evaluated. Extraction sites reopening and gingival invaginations were evaluated in scanned dental models in the posttreatment and 1-year posttreatment stages (mean age 16.1 years). Third molars presence was evaluated at 1-year posttreatment panoramic radiographs, and the facial pattern (SN.GoGn) was evaluated in the initial lateral headfilms. Multiple logistic regression analysis was used to estimate the influence of the aforementioned independent variables on the frequency of extraction space reopening. Results: Space reopening was observed in 20.20% of the subjects 1-year post-debonding. Gingival invaginations were present in 25.73% of quadrants after debonding and in 22.80% 1-year posttreatment. The mean pre-treatment SN.GoGn was 35.64 degrees (SD=5.26). No significant influence was observed of the three independent variables on the instability of extraction site closure. Conclusions: The presence of gingival invaginations, third molars and facial growth pattern do not seem to influence maxillary extraction sites reopening.

RESUMO Introdução: Um efeito colateral observado nos casos tratados com extrações é a instabilidade do fechamento ortodôntico do espaço. Objetivo: O objetivo do presente estudo foi investigar a influência da invaginação gengival, da presença de terceiros molares e do padrão facial na estabilidade do fechamento ortodôntico dos locais de extração na arcada superior. Métodos: Noventa e nove indivíduos (41 homens e 58 mulheres) com má oclusão de Classe I tratados com extração de quatro pré-molares foram avaliados. A reabertura dos locais de extração e as invaginações gengivais foram avaliadas nos modelos dentários digitalizados nos estágios pós-tratamento e um ano pós-tratamento (idade média de 16,1 anos). A presença dos terceiros molares foi avaliada em radiografias panorâmicas de um ano pós-tratamento, e o padrão facial (SN.GoGn) foi avaliado nas radiografias laterais iniciais. Análise de regressão logística múltipla foi utilizada para estimar a influência das variáveis independentes citadas na frequência de reabertura do espaço de extração. Resultados: A reabertura do espaço foi observada em 20,20% dos sujeitos um ano após a remoção do aparelho. Invaginações gengivais estiveram presentes em 25,73% dos quadrantes após a remoção do aparelho e em 22,80% após um ano pós-tratamento. O SN.GoGn pré-tratamento médio foi de 35,64 graus (DP = 5,26). Não foi observada influência significativa das três variáveis independentes sobre a instabilidade do fechamento do local de extração. Conclusões: A presença de invaginações gengivais, terceiros molares e padrão de crescimento facial não parece influenciar na reabertura dos locais de extração maxilar.

Postretention stability after orthodontic closure of maxillary interincisor diastemas.

UNLABELLED: Anterior spaces may interfere with smile attractiveness and compromise dentofacial harmony. They are among the most frequent reasons why patients seek orthodontic treatment. However, midline diastema is commonly cited as a malocclusion with high relapse incidence by orthodontists. OBJECTIVES: This study aimed to evaluate the stability of maxillary interincisor diastemas closure and the association of their relapse and interincisor width, overjet, overbite and root parallelism. MATERIAL AND METHODS: Sample comprised 30 patients with at least a pretreatment midline diastema of 0.5 mm or greater after eruption of the maxillary permanent canines. Dental casts and panoramic radiographs were taken at pretreatment, posttreatment and postretention. RESULTS: Before treatment, midline diastema width was 1.52 mm (SD=0.88) and right and left lateral diastema widths were 0.55 mm (SD=0.56) and 0.57 mm (SD=0.53), respectively. According to repeated measures analysis of variance, only midline diastema demonstrated significant relapse. In the overall sample the average relapse of midline diastema was 0.49 mm (SD=0.66), whilst the unstable patients showed a mean space reopening of 0.78 mm (SD=0.66). Diastema closure in the area between central and lateral incisors showed great stability. Multivariate correlation tests showed that only initial diastema width (ß=0.60) and relapse of overjet (ß=0.39) presented association with relapse of midline diastema. CONCLUSIONS: Midline diastema relapse was statistically significant and occurred in 60% of the sample, while lateral diastemas closure remained stable after treatment. Only initial diastema width and overjet relapse showed association with relapse of midline diastema. There was no association between relapse of interincisor diastema and root parallelism.

Comparison of deflection forces of esthetic archwires combined with ceramic brackets

Abstract Coated archwires and ceramic brackets have been developed to improve facial esthetics during orthodontic treatment. However, their mechanical behavior has been shown to be different from metallic archwires and brackets. Therefore, the aim of this study was to compare the deflection forces in coated nickel-titanium (NiTi) and esthetic archwires combined with ceramic brackets. Material and Methods Non-coated NiTi (NC), rhodium coated NiTi (RC), teflon coated NiTi (TC), epoxy coated NiTi (EC), fiber-reinforced polymer (FRP), and the three different conventional brackets metal-insert polycrystalline ceramic (MI-PC), polycrystalline ceramic (PC) and monocrystalline ceramic (MC) were used. The specimens were set up on a clinical simulation device and evaluated in a Universal Testing Machine (Instron). An acrylic device, representative of the right maxillary central incisor was buccolingually activated and the unloading forces generated were recorded at 3, 2, 1 and 0.5 mm. The speed of the testing machine was 2 mm/min. ANOVA and Tukey tests were used to compare the different archwires and brackets. Results The brackets presented the following decreasing force ranking: monocrystalline, polycrystalline and polycrystalline metal-insert. The decreasing force ranking of the archwires was: rhodium coated NiTi (RC), non-coated NiTi (NC), teflon coated NiTi (TC), epoxy coated NiTi (EC) and fiber-reinforced polymer (FRP). At 3 mm of unloading the FRP archwire had a plastic deformation and produced an extremely low force in 2; 1 and 0.5 mm of unloading. Conclusion Combinations of the evaluated archwires and brackets will produce a force ranking proportional to the combination of their individual force rankings.

Evaluation of the attractiveness of different gingival zeniths in smile esthetics

ABSTRACT Objective: To evaluate the smile attractiveness of different gingival zeniths by general dentists, orthodontists and laypersons and the esthetic perception in the symmetric and asymmetric changes in gingival zeniths. Methods: Posed photographs of five patients were taken and digitally manipulated in Keynote software, in the gingival zenith region, in increments of 0.5 to 1mm in maxillary central and lateral incisors, symmetrically and asymmetrically, in nine different ways for each patient. The photos were then uploaded to a website, where evaluators (general dentists, orthodontists and laypersons) could observe and vote according to their esthetic perception, scoring from 1 to 10, 1 being the least attractive and 10 the more attractive. Kruskal-Wallis and Mann-Whitney tests were used for comparison. Results: Asymmetric gingival zeniths were less attractive than symmetrical gingival zeniths; gingival zenith differences greater than 1mm were perceptible in the smile attractiveness, both by laypersons, general dentists and orthodontists. When comparing maxillary central incisors with maxillary lateral incisors, the aesthetic change performed in the central incisors are more perceptible than those performed in lateral incisors, both symmetrical and asymmetrical. In a general way, orthodontists and general dentists are more critical in the evaluation and perception of gingival zenith changes, with the laypersons perceiving this change only from 1mm of maxillary right central incisor asymmetrical change. Conclusions: Asymmetric gingival zeniths are less attractive than symmetrical ones. Gingival zenith differences greater than 1mm are perceptible in the smile attractiveness. Orthodontists and general dentists are more critical in evaluating smile esthetics.

RESUMO Objetivo: avaliar a atratividade e a percepção estética do sorriso com alterações simétricas e assimétricas dos zênites gengivais, por leigos, dentistas e ortodontistas. Métodos: foram tiradas fotografias posadas de cinco pacientes, de forma padronizada. Cada fotografia foi digitalmente manipulada no software Keynote, na região do zênite gengival, em incrementos de 0,5 a 1 mm, nos incisivos centrais e laterais superiores, de maneira simétrica e assimétrica, de nove formas diferentes para cada paciente. Posteriormente, essas fotografias foram dispostas em um website para que os avaliadores pudessem observá-las e, conforme sua percepção estética, dessem notas de 1 a 10, sendo 1 para pouco atrativa e 10 para muito atrativa. Foram utilizados os testes Kruskal-Wallis e Mann-Whitney para as comparações. Resultados: os zênites gengivais assimétricos foram considerados menos atrativos do que os simétricos. Diferenças entre os zênites gengivais maiores que 1 mm foram perceptíveis na atratividade do sorriso por todos os grupos de avaliadores. Quando comparados os incisivos centrais e laterais superiores, as alterações estéticas feitas nos incisivos centrais foram mais perceptíveis do que as feitas nos laterais, tanto as simétricas quanto as assimétricas. Os ortodontistas e os clínicos gerais foram mais críticos ao avaliar e perceber as alterações, com os leigos percebendo essa mudança somente a partir de 1 mm de alteração assimétrica no incisivo central superior direito. Conclusões: zênites gengivais assimétricos são menos atrativos do que os simétricos. Diferenças nos zênites maiores que 1 mm são perceptíveis na atratividade do sorriso. Ortodontistas e clínicos gerais são mais críticos ao avaliar sorrisos.

Longitudinal stability of rapid and slow maxillary expansion

OBJECTIVE: The aim of this retrospective study was to compare the longitudinal stability of two types of posterior crossbite correction: rapid maxillary expansion (RME) and slow maxillary expansion (SME). METHODS: Study casts of 90 adolescent patients were assessed for interdental width changes at three different periods: pretreatment (T1), post-treatment (T2) and at least, five years post-retention (T3). Three groups of 30 patients were established according to the treatment received to correct posterior crossbite: Group A (RME), group B (SME) and group C (control- Edgewise therapy only). After crossbite correction, all patients received fixed edgewise orthodontic appliances. Paired t-tests and one-way ANOVA were used to identify significant intra and intergroup changes, respectively (P < 0.05). RESULTS: Except for intercanine distance, all widths increased in groups A and B from T1 to T2. In the long-term, the amount of relapse was not different for groups A and B, except for 3-3 widths which showed greater decrease in group A. However, the percentage of clinically relapsed cases of posterior crossbite was similar for rapid and slow maxillary expansion. CONCLUSION: Rapid and slow maxillary expansion showed similar stability in the long-term. .

OBJETIVO: o objetivo desse estudo retrospectivo foi comparar a estabilidade em longo prazo em dois tipos de correção da mordida cruzada posterior, sendo a expansão rápida (ERM) e a expansão lenta da maxila (ELM). MÉTODOS: modelos de estudos de 90 pacientes adolescentes foram avaliados quanto às alterações na largura interdentária em três diferentes tempos: pré-tratamento (T1), pós-tratamento (T2) e pelo menos cinco anos pós-contenção (T3). Três grupos de 30 pacientes foram definidos de acordo com o tratamento realizado para a correção da mordida cruzada posterior: Grupo A (ERM), grupo B (ELM) e grupo C (controle - apenas tratamento com técnica Edgewise). Após correção da mordida cruzada, todos pacientes receberam aparelhos ortodônticos fixos corretivos Edgewise. Teste t pareado e análise de variância a um critério (ANOVA) foram realizados para identificar alterações significantes intra- e intergrupos, respectivamente (p < 0,05). RESULTADOS: exceto para a distância intercaninos, todas as larguras aumentaram nos grupos A e B de T1 para T2. Em longo prazo, a quantidade de recidiva não foi diferente para os grupos A e B, exceto para a largura 3-3, que apresentou uma maior diminuição no grupo A. Clinicamente, entretanto, a porcentagem de casos com recidivas da mordida cruzada posterior foi semelhante para expansões rápida e lenta da maxila. CONCLUSÃO: Expansões rápida e lenta da maxila apresentaram estabilidades semelhantes em longo prazo. .