David Normando

Dental crowding The role of genetics and tooth wear

OBJECTIVE To evaluate the role of genetics and tooth wear in the etiology of dental crowding through the analysis of a split indigenous Amazon population. MATERIALS AND METHODS Dental crowding prevalence (n  =  117), tooth wear (n  =  117), and inbreeding coefficient (n  =  288) were compared for both villages. A biometric investigation was performed by dental cast analysis of 55 individuals with no tooth loss. Mann-Whitney statistics, independent t-tests, and Fisher exact tests were used at P < .05. RESULTS A high coefficient of inbreeding was confirmed in the resultant village (F  =  0.25, P < .001). Tooth wear was not significantly different (P  =  .99), while a significantly higher prevalence of dental crowding was confirmed in the original village (PR  =  6.67, P  =  0.02). Forty dental arches (n  =  20) were examined in the new group, and only one (2.5%) had a dental crowding ≥ 5 mm. In the original villages, we found 20 arches (28.6%) with dental crowding. No difference was observed for tooth size, while larger dental arch dimensions explained a lower level of dental crowding in the resultant village. CONCLUSIONS Our findings downplay the widespread influence of tooth wear, a direct evidence of what an individual ate in the past, on dental crowding and emphasize the role of heredity, exacerbated through inbreeding, in the etiology of this malocclusion.

A escolha do teste estatístico - um tutorial em forma de apresentação em PowerPoint

Selecting appropriate methods for statistical analysis may be difficult, especially for the students and others in the early phases of the research career. On the other hand, PowerPoint presentation is a very common tool to researchers and dental students, so a statistical guide based on PowerPoint could narrow the gap between orthodontist and the Biostatistics. This guide provides objective and useful information about several statistical methods using examples related to the dental field. A Power-Point presentation is employed to assist the user to find answers to common questions regarding Biostatistics, such as the most appropriate statistical test to compare groups, to make correlations and regressions or to look for systematic error for a specific method. Assistance to check normality distribution and to choose the most suitable graphics is also presented. This guide (downloadable in www.dentalpress.com.br) could be even used by reviewers in a quick assessment to check the appropriated statistical methodology into a specific study.Selecting appropriate methods for statistical analysis may be difficult, especially for the students and others in the early phases of the research career. On the other hand, PowerPoint presentation is a very common tool to researchers and dental students, so a statistical guide based on PowerPoint could narrow the gap between orthodontist and the Biostatistics. This guide provides objective and useful information about several statistical methods using examples related to the dental field. A Power-Point presentation is employed to assist the user to find answers to common questions regarding biostatistics, such as the most appropriate statistical test to compare groups, to make correlations and regressions or to look for casual and systematic errors for a specific method. Assistance to check normal distribution and to choose the most suitable graphics is also presented. This guide* could be even used by reviewers in a quick assessment to check the appropriated statistical methodology into a specific study.

Análise do emprego do cálculo amostral e do erro do método em pesquisas científicas publicadas na literatura ortodôntica nacional e internacional

INTRODUCTION: Reliable sample size and an appropriate analysis of error are important steps to validate the data obtained in a scientific study, in addition to the ethical and economic issues. OBJECTIVE: To evaluate, quantitatively, how often the researchers of orthodontic science have used the calculation of sample size and evaluated the method error in studies published in Brazil and in the United States of America. METHODS: Two major journals, according to CAPES (Brazilian Federal Agency for Support and Evaluation of Graduate Education), were analyzed through a hand search: Revista Dental Press de Ortodontia e Ortopedia Facial and the American Journal of Orthodontics and Dentofacial Orthopedics (AJO-DO). Only papers published between 2005 and 2008 were examined. RESULTS: Most of surveys published in both journals employed some method of error analysis, when this methodology can be applied. On the other hand, only a very small number of articles published in these journals have any description of how sample size was calculated. This proportion was 21.1% for the journal published in the United States (AJO-DO), and was significantly lower (p= 0.008) for the journal of orthodontics published in Brazil (3.9%). CONCLUSION: Researchers and the editorial board of both journals should drive greater concern for the examination of errors inherent in the absence of such analyses in scientific research, particularly the errors related to the use of an inadequate sample size.

Influence of the socioeconomic status on the prevalence of malocclusion in the primary dentition

OBJECTIVE: To assess the influence of socioeconomic background on malocclusion prevalence in primary dentition in a population from the Brazilian Amazon. METHODS: This cross-sectional study comprised 652 children (males and females) aged between 3 to 6 years old. Subjects were enrolled in private preschools (higher socioeconomic status - HSS, n = 312) or public preschools (lower socioeconomic status - LSS, n = 340) in Belém, Pará, Brazil. Chi-square and binomial statistics were used to assess differences between both socioeconomic groups, with significance level set at P < 0.05. RESULTS: A high prevalence of malocclusion (81.44%) was found in the sample. LSS females exhibited significantly lower prevalence (72.1%) in comparison to HSS females (84.7%), particularly with regard to Class II (P < 0.0001), posterior crossbite (P = 0.006), increased overbite (P = 0.005) and overjet (P < 0.0001). Overall, malocclusion prevalence was similar between HSS and LSS male children (P = 0.36). Early loss of primary teeth was significantly more prevalent in the LSS group (20.9%) in comparison to children in the HSS group (0.9%), for both males and females (P < 0.0001). CONCLUSION: Socioeconomic background influences the occurrence of malocclusion in the primary dentition. In the largest metropolitan area of the Amazon, one in every five LSS children has lost at least one primary tooth before the age of seven.

Debris and friction of self-ligating and conventional orthodontic brackets after clinical use

OBJECTIVE To compare the degree of debris and friction of conventional and self-ligating orthodontic brackets before and after clinical use. MATERIALS AND METHODS Two sets of three conventional and self-ligating brackets were bonded from the first molar to the first premolar in eight individuals, for a total of 16 sets per type of brackets. A passive segment of 0.019 × 0.025-inch stainless steel archwire was inserted into each group of brackets. Frictional force and debris level were evaluated as received and after 8 weeks of intraoral exposure. Two-way analysis of variance and Wilcoxon signed-rank test were applied at P < .05. RESULTS After the intraoral exposure, there was a significant increase of debris accumulation in both systems of brackets (P < .05). However, the self-ligating brackets showed a higher amount of debris compared with the conventional brackets. The frictional force in conventional brackets was significantly higher when compared with self-ligating brackets before clinical use (P < .001). Clinical exposure for 8 weeks provided a significant increase of friction (P < .001) on both systems. In the self-ligating system, the mean of friction increase was 0.21 N (191%), while 0.52 N (47.2%) was observed for the conventional system. CONCLUSION Self-ligating and conventional brackets, when exposed to the intraoral environment, showed a significant increase in frictional force during the sliding mechanics. Debris accumulation was higher for the self-ligating system.

MEDLINE: international recognition of the development of Brazilian Orthodontic science

Because all I need is free steps, hand in hand, and eyes wide open. Increase in scientific production requires that periodicals be indexed in databases, in order to make information available quickly and systematically to clinical and scientific communities. The main purpose of an indexing service is to ensure prompt access to information and documents of any kind whenever one searches for a specific subject in information systems or databases. Having a journal indexed in a database not only means merit recognition, but also corroborates the quality of published articles. Therefore, all scientific periodicals must comprise , among other features, visibility and accessibility, both of which are facilitated by indexation. We have all witnessed the development of Brazilian Or-thodontics in the last decades. We are no longer seen as mere knowledge consumers once we have become one of the countries with the greatest scientific production in Ortho-dontics in the world. Numerous clinical and scientific awards permeate our daily routine, ratifying our ongoing path. Despite the volcanic eruption of the specialty, our editorial production process has always been discredited. Would we be really capable of producing and maintaining an orthodontic journal with as much quality as the international periodicals used as means to ascend to our scientific success? Dental Press Journal of Orthodontics team always believed so. We have been restlessly working for 18 years in order to achieve the same success as our Brazilian Orthodontics has achieved. Thus, we are happy to announce* that the Dental Press Journal of Orthodontics is indexed in the MEDLINE/ PubMed, the most important database providing references to health sciences information. It is a National Library of Medicine (NLM) journal citation database which has been providing over 22 million bibliographic citations since 1960. Dental Press editors have known, since the publication of its first issue, in 1996, that the aim of scientific journals is to communicate and disclose scientific discussion and development , playing a leading role in breaking paradigms and being responsible for spreading knowledge about new clinical practices. This has been the case since the first publications, initially in the Journal dês Sçavans, a French journal published since 1665, and the Philosophical Transactions of the Royal Society of London, firstly published a few years later. We must bear in mind that databases often carry out evaluations ; therefore, we must keep quality standards, at risk of exclusion. Thus, to refine our criteria for …

Dental and skeletal changes in mild to moderate Class II malocclusions treated by either a Twin-block or Xbow appliance followed by full fixed orthodontic treatment.

OBJECTIVE To compare the short-term skeletal and dental effects of two-phase orthodontic treatment including either a Twin-block or an XBow appliance. MATERIALS AND METHODS This was a retrospective clinical trial of 50 consecutive Class II cases treated in a private practice with either a Twin-block (25) or XBow (25) appliance followed by full fixed orthodontic treatment. To factor out growth, an untreated Class II control group (25) was considered. RESULTS A MANOVA of treatment/observation changes followed by univariate pairwise comparisons showed that the maxilla moved forward less in the treatment groups than in the control group. As for mandibular changes, the corpus length increase was larger in the Twin-block group by 3.9 mm. Dentally, mesial movement of mandibular molars was greater in both treatment groups. Although no distalization of maxillary molars was found in either treatment group, restriction of mesial movement of these teeth was seen in both treatment groups. Both treatment groups demonstrated increased mandibular incisor proclination with larger increases for the XBow group by 3.3°. The Wits value was decreased by 1.6 mm more in the Twin-block group. No sex-related differences were observed. CONCLUSIONS Class II correction using an XBow or Twin-block followed by fixed appliances occurs through a relatively similar combination of dental and skeletal effects. An increase in mandibular incisor inclination for the XBow group and an increased corpus length for the Twin-block group were notable exceptions. No overall treatment length differences were seen.

Angulação dos caninos em indivíduos portadores de má oclusão de Classe I e de Classe III: análise comparativa através de um novo método utilizando imagens digitalizadas

OBJETIVO: determinar as angulacoes mesiodistais das coroas dos caninos em individuos portadores de ma oclusao de Classe III, comparando-os a individuos Classe I. METODOS: foram empregadas medidas tomadas em fotografias digitalizadas de modelos de gesso e transportadas para um programa grafico para leitura das medidas (Image Tool). Tais procedimentos foram repetidos para avaliacao do erro do metodo casual (formula de Dahlberg) e para a analise da reprodutibilidade atraves da Correlacao intraclasse. A amostra constituiu-se de 57 pacientes com denticao permanente completa e nao tratados ortodonticamente, dividida em dois grupos, de acordo com a ma oclusao apresentada: o grupo I foi constituido por 33 pacientes portadores de ma oclusao de Classe I, sendo 16 do sexo masculino e 17 do feminino, com media de idades de 27 anos; o grupo II era representado por 24 pacientes portadores de ma oclusao de Classe III, 20 do sexo masculino e 4 do feminino, com media de idades de 22 anos. RESULTADOS: o erro casual mostrou-se com uma variacao de 1,54 a 1,96 graus para a angulacao dos caninos. A analise estatistica revelou que o metodo apresenta uma excelente reprodutibilidade (p<0,01). Os resultados obtidos na angulacao da coroa dos caninos nao mostraram diferenca estatisticamente significativa entre os caninos superiores nos grupos Classe I e Classe III, embora esse dente mostrasse, em media, uma angulacao 2 graus maior nos individuos Classe III. Entretanto, para os caninos inferiores, foi observada uma diferenca estatisticamente significativa em ambos os lados (p=0,0009 e p=0,0074) entre os grupos Classe I e Classe III. Os pacientes Classe III apresentaram uma menor angulacao nos caninos inferiores em comparacao aos pacientes Classe I, tendendo a acompanhar a compensacao natural dos incisivos, descrita rotineiramente na literatura. CONCLUSAO: os resultados permitem concluir que as compensacoes dentarias, frequentemente observadas na literatura para a regiao de incisivos, se estendem tambem a angulacao dos caninos, principalmente no que se refere a arcada inferior.

The ability of orthodontists and laypeople in the perception of gradual reduction of dentogingival exposure while smiling

OBJECTIVE: To assess differences in how orthodontists and laypersons perceive a reduction in dentogingival display on smiling. METHODS: Sixty examiners from both genders (30 laypersons and 30 orthodontists) evaluated photographs of spontaneous smiles of two subjects , one male and one female. Based on the original images, smile height was modified by means of an image manipulation software program. The examiners assigned scores ranging from 0 to 10, according to the level of pleasantness. Method reproducibility was examined using the Wilcoxon test, while the Friedman and Wilcoxon tests (p 0.05). CONCLUSIONS: women smiles achieved higher scores than men smiles however, samples involving a larger number of subjects in each group are required to ensure whether or not this finding is linked to the subjects gender.

In vivo color changes of esthetic orthodontic ligatures

OBJECTIVE: To assess the color changes that occur in four commercial brands of esthetic orthodontic elastomeric ligatures after exposure to the oral environment. METHODS: The four elastomeric ligatures manufacturers mostly mentioned by orthodontists were investigated: Morelli, Uniden, American Orthodontics (AO) and TP. The sample comprised 25 patients. The elastomeric ligatures were randomly distributed and arranged in the four dental quadrants of each patient, r for 30 days. After this period, two units of each brand were photographed in a standardized manner. Subsequently, color changes were visually evaluated and assigned a score (0, 1, 2 or 3) by a panel of four examiners. The mean scores assigned by the examiners were statistically analyzed by ANOVA and Tukeys test (p < 0.05). RESULTS: The mean pigmentation scores assigned to Morelli (1.80 ± 0.78) and Uniden (1.92 ± 0.66) elastomeric ligatures after 30 days in the oral environment were not statistically different. However, these brands were significantly more pigmented after 30 days in the oral environment (p < 0.01) compared to American Orthodontics (0.97 ± 0.6) and TP (0.83 ± 0.79). CONCLUSIONS: Although all four brands exhibited an undesirable pigmentation after 30 days in the oral environment, color change for American Orthodontics and TP Orthodontics ligatures was significantly lower than Morelli and Uniden products.