Golden Proportion Analysis of Dental-Skeletal Patterns of Class II and III Patients Pre and Post Orthodontic-orthognathic Treatment.

INTRODUCTION: The golden proportion has been used in dentistry in an attempt to improve facial function and, possibly, esthetics by simplifying the diagnosis of facial and dental disharmony. The aim of this study is to analyze pre- and postoperative cephalometric tracings of lateral cephalograms of patients with class II and III deformities submitted to orthognathic surgery, and verify if the 13 dental-skeletal patterns (ratios), as defined by Ricketts, moved closer to or further away from the golden proportion. MATERIALS AND METHODS: A total of 110 lateral cephalometric radiographs, 55 obtained preoperatively and 55 postoperatively, were analyzed using Dolphin Imaging software. RESULTS: Radiographs analysis demonstrated that ratios 1, 3, 4, 5, 7, 8, 9, 10, and 13 remained statistically different from the golden proportion postoperatively. Ratio 12 was the only one to move closer to the golden number, while the opposite happened with ratio 6, which moved further away after the surgery. Ratios 2 and 11 kept statistically similar to the golden proportion both pre and postoperatively. CONCLUSION: It may be concluded that orthognathic surgery had little effect on the proportions studied, and that the golden proportion was not present in the majority of the ratios analyzed neither before nor after surgery. CLINICAL SIGNIFICANCE: Determine whether the facial patterns approach the golden ratio after surgical correction. Also determine whether the golden ratio may be a standard to guide the surgical treatment of patients with skeletal patterns of type II and III.

Dental arches in inherited severe isolated growth hormone deficiency.

OBJECTIVES: The growth of the dental arches depends on GH and insulin-like growth factor type 1 (IGF1), but the consequences of GH deficiency (GHD) on their growth are still unclear, probably due to the acquired etiology of GHD in most described series, often associated with additional pituitary deficits (thyrotrophic, corticotrophic and gonadotrophic hormones), and imperfections of related replacement therapies, which may affect the dental arch growth. To avoid these limitations, we took advantage of a unique cohort of subjects with isolated GH deficiency (IGHD) due the same mutation in the GH releasing hormone receptor gene, living with very low serum GH and low to undetectable circulating IGF1 levels. Our purpose was to analyze the dimensions of maxillary and mandibular dental arches. METHODS: 22 adult IGHD (15 untreated and 7 previously partially treated with GH) and 33 controls were enrolled in a cross-sectional study using the Ortho Insight 3D and MeshMixer software, RESULTS: In untreated IGHD subjects all maxillary arch measures were smaller than controls, while among mandibular arches, only the mandibular canine width and the mandibular arch length were reduced. In partially GH treated subjects only the palate depth, the maxillary canine width, the maxillary and mandibular arch lengths remained smaller than controls. CONCLUSIONS: IGHD reduces the growth of maxillary arch to a greater degree than the mandibular arch, suggesting different control of superior and inferior dental arches. GH treatment increases some of these measures.

Effect of rapid maxillary expansion on nasal cavity assessed with cone-beam computed tomography.

INTRODUCTION: Rapid maxillary expansion (RME) is assumed as a well established procedure; although, some effects on facial complex are not yet fully understood. OBJECTIVE: The aim of this research was to verify, using cone-beam computed tomography, the effect on linear dimensions of the nasal cavity. METHODS: Sample consisted of twenty patients aged 7 to 16 years, with skeletal deformity that justified the use of CT scans, and who required the RME as part of the orthodontic treatment planning. Scans were taken before clinical procedures were performed (T0) and after stabilizing the expander screw (T1). Dolphin Imaging v. 11.5 3D software was used to measure six areas on nasal cavity: three at the anterior portion (upper, middle, and lower) and other three at the posterior portion (also upper, middle, and lower). Data were statistically treated using Shapiro-Wilk test to verify normality. Differences between T0 and T1 were calculated using the Spearman correlation and paired Student's t-test, with a significance level of 5%. RESULTS: All linear measurements presented a significant increase (p< 0.05) after RME, both in the anterior and posterior regions, suggesting some parallelism on the opening pattern, especially at the lower portion (p< 0.001). CONCLUSIONS: RME was able to significantly modify the internal dimensions of the nasal cavity.

Reliability and accuracy of linear measurements in cone-beam computed tomography using different software programs and voxel sizes.

OBJECTIVES: The aim of this study is to evaluate the accuracy of linear measurements on cone-beam computed tomography (CBCT) images using three software programs and different voxel sizes. METHODS: Ten human mandibles with 25 silica markers were scanned for 0.250-, 0.300-, and 0.400-mm voxels in the i-CAT New Generation (Imaging Sciences International, Hatfield, PA, USA). Thirty-five linear measurements were carried out by two examiners two times on the multiplanar reconstructions in the following software programs: XoranCat version 3.1.62 (Xoran Technologies, Ann Arbor, MI, USA), RadiAnt DICOM 2.2.9 Viewer (Medixant, Poznan- Poland) and InVesalius 3.0.0 (Centro de Tecnologia da Informação Renato Archer, Campinas, SP, Brazil). The physical measurements were made by another observer two times using a digital caliper on the macerated mandibles. ANOVA test was used to compare voxels and software programs. Pearson correlation and the Bland-atman tests were used to compare physical and virtual measurements and to evaluate the accuracy of the software programs, respectively (P < 0.05). RESULTS: There was no statistically significant difference when the measurements were compared in acquisitions with different voxel sizes analyzed in the three software programs. There was also no difference when the measurements were compared between the software programs and the digital caliper. Excellent intra- and inter-observer reliability for the markers, physical measurements, and multiplanar reconstructions were found. CONCLUSION: Linear measurements in the XoranCat, Radiant, and InVesalius software programs are reliable and accurate compared with physical measurements. The different acquisition protocols using different voxel sizes did not influence the accuracy of linear measurements in CBCT images.

Atypical oral features of patient with neurofibromatosis type 1: case report / Características orais atípicas de paciente com neurofibromatose tipo 1: relato de caso

RESUMEN El propósito de este artículo es ayudar a los dentistas clínicos a identificar la neurofibromatosis tipo 1 y sus variantes. Presentamos un caso raro de un hombre de 68 años, afectado desde la infancia por la presencia de nódulos generalizados en todo el cuerpo, provocando deformaciones estéticas. Curiosamente, el impacto en la cavidad oral no fue significativo, con nódulos solo en la encía, un área de manifestación raro. La radiografía panorámica mostró un ligero agrandamiento del canal mandibular. Tras un año de seguimiento, el paciente falleció por complicaciones cardiovasculares provocadas por el síndrome.

Large calcifying odontogenic cyst in the posterior maxilla / Extenso cisto odontogênico calcificante em maxila posterior

RESUMEN La aparición de un quiste odontogénico calcificante (QOC) en la región posterior de la maxila es infrecuente; hay pocos informes descritos en la literatura. Presentamos el caso de una paciente de 13 años que presentó una lesión extensa en la maxila izquierda (> 7,5 cm). La radiografía panorámica mostró una lesión radiolúcida unilocular bien delimitada, que se extendía desde el maxilar posterior izquierdo hasta el seno maxilar. La paciente fue sometida a descompresión, seguida de de la extirpación quirúrgica conservadora de la lesión. El análisis histológico de la pieza quirúrgica confirmó el diagnóstico de QOC. Después de un año, no se observaron recurrencias. La paciente permanece en seguimiento regular.

Effect of rapid maxillary expansion on nasal cavity assessed with cone-beam computed tomography

ABSTRACT Introduction: Rapid maxillary expansion (RME) is assumed as a well established procedure; although, some effects on facial complex are not yet fully understood. Objective: The aim of this research was to verify, using cone-beam computed tomography, the effect on linear dimensions of the nasal cavity. Methods: Sample consisted of twenty patients aged 7 to 16 years, with skeletal deformity that justified the use of CT scans, and who required the RME as part of the orthodontic treatment planning. Scans were taken before clinical procedures were performed (T0) and after stabilizing the expander screw (T1). Dolphin Imaging v. 11.5 3D software was used to measure six areas on nasal cavity: three at the anterior portion (upper, middle, and lower) and other three at the posterior portion (also upper, middle, and lower). Data were statistically treated using Shapiro-Wilk test to verify normality. Differences between T0 and T1 were calculated using the Spearman correlation and paired Student's t-test, with a significance level of 5%. Results: All linear measurements presented a significant increase (p< 0.05) after RME, both in the anterior and posterior regions, suggesting some parallelism on the opening pattern, especially at the lower portion (p< 0.001). Conclusions: RME was able to significantly modify the internal dimensions of the nasal cavity.

RESUMO Introdução: A expansão rápida da maxila (ERM) é um procedimento bem estabelecido. Entretanto, alguns efeitos no complexo facial ainda não foram completamente compreendidos. Objetivo: O objetivo do presente estudo foi verificar o efeito da ERM nas medidas lineares da cavidade nasal, utilizando a tomografia computadorizada de feixe cônico (TCFC). Métodos: A amostra foi composta por 20 pacientes da Universidade Federal da Bahia, com idades entre 7 e 16 anos, com deformidades esqueléticas que justificavam o uso da TCFC e que necessitavam da ERM como parte do tratamento ortodôntico. As imagens tomográficas foram realizadas antes dos procedimentos clínicos (T0) e após estabilização do parafuso expansor (T1). O software Dolphin Imaging v. 11.5 3D (Dolphin, Chatsworth, CA, EUA) foi utilizado para mensurar seis áreas na cavidade nasal, três delas na região anterior (superior, média e inferior) e outras três na região posterior (também superior, média e inferior). Os dados foram trabalhados estatisticamente, utilizando o teste de Shapiro-Wilk para avaliar a normalidade. Diferenças entre T0 e T1 foram calculadas usando a Correlação de Spearman e o teste t de Student pareado, usando um nível de significância de 5%. Resultados: Todas as mensurações lineares apresentaram um aumento significativo (p< 0,05) após a ERM, tanto na região anterior quanto na posterior, sugerindo algum paralelismo no padrão de abertura, principalmente na porção inferior (p< 0,001). Conclusão: A ERM foi capaz de modificar significativamente as dimensões internas da cavidade nasal.