Lateral cephalometric diagnosis of asymmetry in Angle Class II subdivision compared to Class I and II

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Masticatory efficiency in class II and class III dentofacial deformities

Masticatory efficiency may be impaired in individuals with dentofacial deformities. The objective of the present study was to determine the condition of masticatory efficiency in individuals with dentofacial deformities. 30 patients with class II (DG-II) and 35 patients with class III (DG-III) dentofacial deformity participated in the study, all had an indication for orthognathic surgery. 30 volunteers (CG) with no alterations of facial morphology or dental occlusion and with no signs or symptoms of temporomandibular joint dysfunction also participated. Masticatory efficiency was analysed using a bead system (colorimetric method). Each individual chewed 4 beads, one at a time, over 20 s measured with a chronometer. The groups were compared in term's of masticatory efficiency using analysis of variance (ANOVA), with the level of significance set at P < 0.05. Masticatory efficiency was significantly greater in CG (P < 0.05) than in DG-II and DG-III in all chewing tasks tested, with no significant difference between DG-II and DG-III (P > 0.05). It was observed that the presence of class II and class III dentofacial deformity affected masticatory efficiency compared to CG, although there was no difference between DG-II and DG-III.

Influence of intentional ankylosis of deciduous canines to reinforce the anchorage for maxillary protraction

Introduction: This retrospective cephalometric study analyzed the influence of intentional ankylosis of deciduous canines in patients with Class III malocclusion and anterior crossbite, in the deciduous and early mixed dentition stages, treated by orthopedic maxillary expansion followed by maxillary protraction. Methods: Lateral cephalograms of 40 patients were used, divided in 2 groups paired for age and gender. The Ankylosis Group was composed of 20 patients (10 boys and 10 girls) treated with induced ankylosis and presenting initial and final mean ages of 7 years 4 months and 8 years 3 months, respectively, with a mean period of maxillary protraction of 11 months. The Control Group comprised 20 patients (10 boys and 10 girls) treated without induced ankylosis, with initial and final mean ages of 7 years 8 months and 8 years 7 months, respectively, with a mean period of maxillary protraction of 11 months. Two-way analysis of variance and covariance analysis were applied to compare the initial and final cephalometric variables and the treatment changes between groups. Results: According to the results, the variables evidencing the significant treatment changes between groups confirmed that the intentional ankylosis enhanced the sagittal response of the apical bases (Pg-NPerp) and increased the facial convexity angles (NAP and ANB). Conclusions: The protocol involving intentional ankylosis of deciduous canines enhanced the sagittal response of the apical bases.

Cromosomal location of four genes encoding Class III peroxidases in wheat

In a previous work, deduced amino acid sequences from twenty wheat peroxidase genes were assigned to seven groups designated as TaPrx108 to TaPrx114. Some of these apoplastic peroxidases have previously shown to play different roles in the plant defense responses to infection by the cereal cyst nematode Heterodera avenae. In the present study, PCR marker analysis using Sears’s aneuploid wheat lines cv. ‘Chinese Spring’ was used to locate four genes encoding peroxidase isozymes. The TaPrx111-A, TaPrx112-D and TaPrx113-F genes were located on the short arm of chromosome 2B and the TaPrx109-C on the long arm of chromosome 1B. These results would agree with the synteny between wheat and rice chromosomes previously established in other studies.

Pea formaldehyde-active class III alcohol dehydrogenase: common derivation of the plant and animal forms but not of the corresponding ethanol-active forms (classes I and P).

A plant class III alcohol dehydrogenase (or glutathione-dependent formaldehyde dehydrogenase) has been characterized. The enzyme is a typical class III member with enzymatic parameters and substrate specificity closely related to those of already established animal forms. Km values with the pea enzyme are 6.5 microM for NAD+, 2 microM for S-hydroxymethylglutathione, and 840 microM for octanol versus 9, 4, and 1200 microM, respectively, with the human enzyme. Structurally, the pea/human class III enzymes are closely related, exhibiting a residue identity of 69% and with only 3 of 23 residues differing among those often considered in substrate and coenzyme binding. In contrast, the corresponding ethanol-active enzymes, the long-known human liver and pea alcohol dehydrogenases, differ more (47% residue identities) and are also in functionally important active site segments, with 12 of the 23 positions exchanged, including no less than 7 at the usually much conserved coenzyme-binding segment. These differences affect functionally important residues that are often class-distinguishing, such as those at positions 48, 51, and 115, where the plant ethanol-active forms resemble class III (Thr, Tyr, and Arg, respectively) rather than the animal ethanol-active class I forms (typically Ser, His, and Asp, respectively). Calculations of phylogenetic trees support the conclusions from functional residues in subgrouping plant ethanol-active dehydrogenases and the animal ethanol-active enzymes (class I) as separate descendants from the class III line. It appears that the classical plant alcohol dehydrogenases (now called class P) have a duplicatory origin separate from that of the animal class I enzymes and therefore a paralogous relationship with functional convergence of their alcohol substrate specificity. Combined, the results establish the conserved nature of class III also in plants, and contribute to the molecular and functional understanding of alcohol dehydrogenases by defining two branches of plant enzymes into the system.

Class III injection wells and your drinking water.

Mode of access: Internet.

Percepção dos Ortodontistas quanto à época ideal para o tratamento ortodôntico da má oclusão de Classe II de Angle.

O objetivo deste estudo foi verificar, por meio de questionário, a percepção dos ortodontistas quanto a época ideal para o tratamento ortodôntico da má oclusão de Classe II de Angle, avaliar a eficiência deste tipo de tratamento em uma ou duas fases e identificar os diversos métodos de tratamento utilizados. A amostra constituiu de 163 ortodontistas brasileiros que responderam ao questionário via e-mail. O questionário continha perguntas do tipo aberta, semi aberta e fechada, e, para sua validação, foi realizado um teste piloto entre 15 ortodontistas, participantes ou ex-alunos do Programa de Pós-graduação em Odontologia da Universidade Metodista de São Paulo, que não foram inclusos neste trabalho. Os dados foram tabulados com a utilização de frequência absoluta (n) e frequência relativa (%). Para verificar a correlação entre as variáveis ordinais foi utilizado o Coeficiente de Correlação de Spearman. Para verificar a associação entre variáveis qualitativas nominais foi utilizado o teste do qui-quadrado. Em todos os testes foi adotado nível de significância de 5% (p<0,05). Todos os procedimentos estatísticos foram executados no programa Statistica v.5.1 (StatSoft Inc., Tulsa, USA). Observou-se que os ortodontistas brasileiros preferem tratar os pacientes portadores da má oclusão de Classe II durante a fase da dentadura mista tardia, onde a procura por tratamentos nos consultórios e/ou clínicas tem maior ocorrência entre 10 a 13 anos e no sexo feminino. Dentre as modalidades de tratamento, verificou-se que 25 a 50% dos profissionais tratam seus pacientes em duas fases, seja na utilização do Aparelho Extra Bucal (49,1%), Bionator (33,1%) ou propulsores mandibulares, como APM (17,8%), e, Elásticos Classe II (8,6%).

Crescimento facial espontâneo Padrão II: estudo cefalométrico longitudinal

OBJETIVO: o presente estudo cefalométrico longitudinal investigou as alterações espontâneas ocorridas em crianças com má oclusão Classe II, divisão 1, Padrão II. MÉTODOS: foram selecionadas 40 crianças, 20 meninos e 20 meninas, distribuídas na faixa etária compreendida entre 6 e 14 anos de idade. Para avaliar o comportamento das bases apicais, dos incisivos e do tecido mole, as seguintes grandezas cefalométricas foram mensuradas: SN.Ba, SNA, SNB, SND, SN.Pog, ANB, NAP, SN.PP, SN.GoGn, SN.Gn, Ar.Go.Gn, 1.PP, 1.NA, 1.SN, IMPA e ANL. As seguintes grandezas alcançaram significância estatística com o crescimento: SNB, SND,SN.Pog,ANB,NAP,SN.GoGn,SN.Gn,Ar.Go.Gn e IMPA. RESULTADOS: os resultados demonstraram que as principais alterações quantitativas registradas estavam relacionadas com o crescimento mandibular,independentemente do gênero. A mandíbula deslocou-se para frente, com tendência de rotação no sentido anti-horário e com conseqüente redução nos ângulos de convexidade facial. No entanto, as oscilações quantitativas nas grandezas cefalométricas não foram suficientes para mudar a morfologia dentofacial ao longo do período de acompanhamento. CONCLUSÃO: conclui-se, portanto, que a morfologia facial é definida precocemente e é mantida, configurando o determinismo genético na determinação do arcabouço esquelético.

Maxillary and mandibular width changes studied using metallic implants.

The purpose of this implant study was to evaluate the transverse stability of the basal maxillary and mandibular structures. The sample included 25 subjects between 12 and 18 years of age who were followed for approximately 2.6 years. Metallic implants were placed bilaterally into the maxillary and mandibular corpora before treatment. Once implant stability had been confirmed, treatment (4 first premolar extractions followed by fixed appliance therapy) was initiated. Changes in the transverse maxillary and mandibular implants were evaluated cephalometrically and two groups (GROW+ and GROW++; selection based on growth changes in facial height and mandibular length) were compared. The GROW++ group showed significant width increases of the posterior maxillary implants (P <.001) and the mandibular implants (P =.009); there was no significant change for the anterior maxillary implants. The GROW+ group showed no significant width changes between the maxillary and mandibular implants. We conclude that (1) there are significant width increases during late adolescence of the basal mandibular and maxillary skeletal structures and (2) the width changes are related with growth potential.

Effects of cervical headgear and edgewise appliances on growing patients

Maxillary basal bone, dentoalveolar, and dental changes in Class II Division 1 patients treated to normal occlusion by using cervical headgear and edgewise appliances were retrospectively evaluated. A sample of 45 treated patients was compared with a group of 30 untreated patients. Subjects were drawn from the Department of Orthodontics, Araraquara School of Dentistry, Brazil, and ranged in age from 7.5 to 13.5 years. The groups were matched based on age, gender, and malocclusion. Roughly 87% of the treated group had a mesocephalic or brachicephalic pattern, and 13% had a dolicocephalic pattern. Cervical headgear was used until a Class I dental relationship was achieved. Our results demonstrated that the malocclusions were probably corrected by maintaining the maxillary first molars in position during maxillary growth. Maxillary basal bone changes (excluding dentoalveolar changes) did not differ significantly between the treated and the untreated groups. Molar extrusion after the use of cervical headgear was not supported by our data, and this must be considered in the treatment plan of patients who present similar facial types. (Am J Orthod Dentofacial Orthop 2001;119:531-9).

Short-term treatment effects produced by the herbst appliance in the mixed dentition

This prospective clinical investigation evaluates the dentoalveolar and skeletal cephalometric changes produced by the Herbst appliance during treatment of mixed dentition patients with Class II division 1 malocclusion. Thirty individuals (15 male and 15 female individuals; initial mean age nine years 10 months) were treated with the Herbst appliance for a period of 12 months. For comparison, the records of 30 untreated Class II children (15 boys, 15 girls; initial mean age nine years eight months) were followed without treatment for a period of 12 months. The results indicated that the treatment effects produced in the mixed dentition patients were primarily dentoalveolar in nature. The mandibular incisors were tipped labially, and the maxillary incisors were retruded; a significant increase in mandibular posterior dentoalveolar height occurred, and there was a restriction in the vertical development of the maxillary molars. There was no difference in the forward growth of the maxilla between the two groups. In comparison with the controls, however, the Herbst treatment produced a modest but statistically significant increase in total mandibular length. This increase in total mandibular length, however, was less than that observed in adolescent Herbst patients in other studies. © 2005 by The EH Angle Education and Research Foundation, Inc.

Occurrence, extension, and severity of gingival margin alterations after orthodontic treatment.

To assess the occurrence, extension, and severity of gingival margin alterations in a sample of youth after orthodontic treatment. Records from 209 Caucasian adolescents (118 female and 91 male) before and after orthodontic treatment were selected. Patients presented a mean age at the beginning of orthodontic treatment of 11.20 ± 1.86 years and a final mean age of 14.72 ± 1.83 years. Class I and II patients with mandibular incisors and canines that were completely erupted and with spacing or crowding not exceeding 4 mm were evaluated. The presence of gingival recession on the labial surface of the mandibular anterior teeth was evaluated in intraoral photographs and casts made before and after treatment. The proportion of patients with gingival recession after treatment was statistically higher than at the beginning (P<.001). After orthodontic treatment, gingival recession was not present in any of the teeth for 63.6% of the patients; in 29.2% of the patients, recession was present in at least 1 tooth. In terms of severity, the majority of affected teeth (47%) presented gingival recession less than 2 mm and in 2% more than 4 mm. It may be concluded that alterations in the gingival margin, especially gingival recession, occur in patients after orthodontic therapy, but the extent and severity of this finding are low. COPYRIGHT © 2007 BY QUINTESSENCE PUBLISHING CO, INC.

Electromyographic evaluation of the upper lip according to the breathing mode: A longitudinal study

The present study aimed at analyzing and comparing longitudinally the EMG (electromyographic activity) of the superior orbicularis oris muscle according to the breathing mode. The sample, 38 adolescents with Angle Class II Division 1 malocclusion with predominantly nose (PNB) or mouth (PMB) breathing, was evaluated at two different periods, with a two-year interval between them. For that purpose, a 16-channel electromyography machine was employed, which was properly calibrated in a PC equipped with an analogue-digital converter, with utilization of surface, passive and bipolar electrodes. The RMS data (root mean square) were collected at rest and in 12 movements and normalized according to time and amplitude, by the peak value of EMG, in order to allow comparisons between subjects and between periods. Comparison of the muscle function of PNB and PMB subjects at period 1 (P1), period 2 (P2) and the variation between periods (Δ) did not reveal statistically significant differences between groups (p < 0.05). However, longitudinal evaluation of the muscle function in PNB and PMB subjects demonstrated different evolutions in the percentage of required EMG for accomplishment of the movements investigated. It was possible to conclude that there are differences in the percentage of electric activity of the upper lip with the growth of the subjects according to the breathing mode.