Comparison of changes in the dental transverse and sagittal planes between patients treated with self-ligating and with conventional brackets

ABSTRACT Introduction: Several advantages have been established regarding the efficiency of self-ligating brackets (SL). In spite of some controversy surrounding this question in the literature, clinical results confirm that "arch development" requires fewer extractions. Objective: The objective of this study was to compare changes in the transverse and sagittal planes in patients treated with conventional ligating brackets (CL)as well as in patients treated with SL brackets and oversized arches. Methods: A sample was selected from a pool of 300 consecutive cases treated by a single clinician: 51 patients with SL brackets and oversized wires, and 55 with CL brackets. These two groups were compared with a control group of 20 patients. All plaster models were scanned and dental landmarks were measured to identify changes from commencement (T0) to conclusion (T1) of treatment. Lateral cephalograms were analyzed for changes in the lower incisor (IMPA) and the first lower molar distal angulation (MAng). Intraoperator reliability was tested with linear regression analysis. To assure all groups were comparable at T0, an ANOVA test with a 95%confidence interval (CI) was performed for all values. To assess changes from T0 to T1 in all groups, a Student's t-test with 95% CI was used. Finally, results from the three groups were compared using an ANOVA-test (95% CI) and a post-hoc test. Results: Increases in all the transverse variables were recorded in the two groups treated (SL and CL), except for the lower intercanine distance in the SL group. IMPA difference from T0 to T1 was higher in the CL group, and molar distal angulation (MAng) took place in the SL group. Conclusions: Self-ligating brackets with oversized arches and conventional ligating brackets showed increases in all variables in the transverse plane, except for the SL group at the mandibular intercanine distance. In comparison with the CL group, fewer different IMPA values were observed in the SL group, in which distal molar angulation occurred.

RESUMO Introdução: Já foram enumeradas diversas vantagens quanto à eficiência dos braquetes autoligáveis (BAL). Apesar das controvérsias na literatura, resultados clínicos confirmam que o "desenvolvimento da arcada" demanda menos extrações. Objetivo: O objetivo deste estudo foi comparar as mudanças nos planos transversal e sagital em pacientes tratados com braquetes convencionais (BC) e pacientes tratados com BAL e arcos superdimensionados. Métodos: A amostra foi selecionada de um grupo de 300 pacientes tratados consecutivamente por um mesmo ortodontista: 51 pacientes com BAL e arcos superdimensionados, e 55 com BC. Esses dois grupos foram comparados a um grupo controle (GC) de 20 pacientes. Todos os modelos de gesso foram escaneados e pontos de referência dentários foram mensurados, para se identificar as mudanças entre o início (T0) e o fim do tratamento (T1). Radiografias cefalométricas laterais foram analisadas para identificar mudanças nos incisivos inferiores (IMPA) e na angulação distal dos primeiros molares inferiores (MAng). A confiabilidade intraexaminador foi testada por meio de uma análise de regressão linear. Para garantir que os grupos fossem comparáveis em T0, realizou-se o teste ANOVA com intervalo de confiança (IC) de 95% para todos os valores. Para avaliar as mudanças entre T0 e T1 em todos os grupos, foi utilizado o teste t de Student com IC de 95%. Por fim, os resultados dos três grupos foram comparados utilizando-se o teste ANOVA (IC 95%) e um teste post-hoc. Resultados: Foram registrados aumentos em todas as variáveis transversais nos dois grupos tratados (BC e BAL), com exceção da distância intercaninos inferiores no grupo BAL. As maiores diferenças de T0 para T1 ocorreram no IMPA do grupo BC e na angulação distal de molares (MAng) do grupo BAL. Conclusões: Ambos os grupos, BAL com arcos superdimensionados e BC, apresentaram aumento em todas as variáveis no plano transversal, com exceção da distância intercaninos inferiores no grupo BAL. Em comparação ao grupo BC, menores diferenças nos valores de IMPA foram observadas no grupo BAL, no qual aconteceu angulação distal de molares.

Cloning and molecular characterization of a putative habanero pepper SERK1 cDNA expressed during somatic and zygotic embryogenesis

Background: Plant gene homologs that control cell differentiation can be used as biotechnological tools to study the in vitro cell proliferation competence of tissue culture-recalcitrant species such as peppers. It has been demonstrated that SERK1 homologs enhance embryogenic competence when overexpressed in transformed tissues; therefore, cloning of a pepper SERK1 homolog was performed to further evaluate its biotechnological potential. Results: A Capsicum chinense SERK full-length cDNA (CchSERK1) was cloned and characterized at the molecular level. Its deduced amino acid sequence exhibits high identity with sequences annotated as SERK1 and predicted-SERK2 homologs in the genomes of the Capsicum annuum CM-334 and Zunla-1 varieties, respectively, and with SERK1 homologs from members of the Solanaceae family. Transcription of CchSERK1 in plant tissues, measured by quantitative RT-PCR, was higher in stems, flowers, and roots but lower in leaves and floral primordia. During seed development, CchSERK1 was transcribed in all zygotic stages, with higher expression at 14 days post anthesis. During somatic embryogenesis, CchSERK1 was transcribed at all differentiation stages, with a high increment in the heart stage and lower levels at the torpedo/cotyledonal stages. Conclusion: DNA sequence alignments and gene expression patterns suggest that CchSERK1 is the C. chinense SERK1 homolog. Significant levels of CchSERK1 transcripts were found in tissues with cell differentiation activities such as vascular axes and during the development of zygotic and somatic embryos. These results suggest that CchSERK1 might have regulatory functions in cell differentiation and could be used as a biotechnological tool to study the recalcitrance of peppers to proliferate in vitro.

Cloning of the Coffea canephora SERK1 promoter and its molecular analysis during the cell-to-embryo transition

Background: Somatic embryogenesis receptor-like kinase 1 (SERK1) is a cell membrane receptor active in different plant tissues and involved in cell differentiation activities including somatic embryogenesis. The identification of promoter elements responsible for SERK1 expression during the onset of somatic embryogenesis can be useful to understand the molecular regulation of the cell-to embryo transition, and these promoter elements represent biotechnological tools in plant organ tissue culture. Results: A −1,620 bp DNA sequence located upstream of the Coffea canephora SERK1 gene homologue (CcSERK1) was isolated, and then, different segments containing key response elements (REs) for somatic embryogenesis onset and development were fused to the uidA (encoding a ß-glucuronidase, GUS) reporter gene to evaluate its expression in transgenic leaf explants. DNA segments of −1,620 and −1048 bp in length directed uidA expression with patterns in leaf explants similar to those occurring during somatic embryogenesis. When a −792-bp fragment was used, uidA expression disappeared only in leaf explants and pro-embryogenic mass but persisted in developing embryos. No uidA expression was detected in any embryogenic stage when a −618-bp fragment was used. Conclusion: DNA deletions showed that a −1048-bp sequence located upstream of the CcSERK1 gene is sufficient to direct gene expression during the onset and the development of C. canephora somatic embryogenesis. The DNA segment located between −1048 and −792 bp (containing BBM and WUS REs) is needed for gene expression before embryogenesis onset but not during embryo development. The promoter segment between −792 and −618 bp (including GATA, ARR1AT, and ANT REs) regulates gene expression in developing embryos.

Agrobacterium tumefaciens-transient genetic transformation of Habanero pepper (Capsicum chinense Jacq. ) leaf explants

Most of the pepper species of the genus Capsicum have been recalcitrant to efficient Agrobacterium tumefaciens-mediated stable or transient, genetic transformation. In the present work, we optimized a protocol for transient transformation of the Habanero pepper (Capsicum chinense Jacq.) through the standardization of several experimental factors. These included the age of the plants, the temperature, the length of co-cultivation, the application of a negative (vacuum) and/or a positive (infiltration) pressure, along with micro injection, the use of acetosyringone during the bacterial culturing, and modification of the pH during the GUS assay to eliminate the endogenous beta-glucuronidase activity. The standardized protocol, which yielded nearly 55 percent fully transformed leaf explants, was used to successfully mobilize two empty binary vectors (pCAMBIA2301 and pCAMex), as well as the C. chinense cDNAs encoding the pathogenesis-related protein 10 and esterase, respectively.