RESUMO
Witkop syndrome, also known as tooth and nail syndrome (TNS), is a rare autosomal dominant disorder. Affected individuals have nail dysplasia and several congenitally missing teeth. To identify the gene responsible for TNS, we used candidate-gene linkage analysis in a three-generation family affected by the disorder. We found linkage between TNS and polymorphic markers surrounding the MSX1 locus. Direct sequencing and restriction-enzyme analysis revealed that a heterozygous stop mutation in the homeodomain of MSX1 cosegregated with the phenotype. In addition, histological analysis of Msx1-knockout mice, combined with a finding of Msx1 expression in mesenchyme of developing nail beds, revealed that not only was tooth development disrupted in these mice, but nail development was affected as well. Nail plates in Msx1-null mice were defective and were thinner than those of their wild-type littermates. The resemblance between the tooth and nail phenotype in the human family and that of Msx1-knockout mice strongly supports the conclusions that a nonsense mutation in MSX1 causes TNS and that Msx1 is critical for both tooth and nail development.
Assuntos
Anodontia/genética , Códon sem Sentido/genética , Ligação Genética/genética , Proteínas de Homeodomínio/genética , Unhas Malformadas/genética , Fatores de Transcrição , Adulto , Sequência de Aminoácidos , Animais , Anodontia/embriologia , Sequência de Bases , Mapeamento Cromossômico , Análise Mutacional de DNA , Feminino , Genes Dominantes/genética , Heterozigoto , Proteínas de Homeodomínio/química , Proteínas de Homeodomínio/metabolismo , Humanos , Hibridização In Situ , Fator de Transcrição MSX1 , Masculino , Camundongos , Camundongos Knockout , Unhas Malformadas/embriologia , Linhagem , Fenótipo , Polimorfismo Genético/genética , Estrutura Terciária de Proteína , RNA Mensageiro/análise , RNA Mensageiro/genética , SíndromeRESUMO
Using a powerful three dimensional perspective, it is possible to control the vertical components of bite opening appliances, which can prove to be valuable in design and application of functional appliances. Several cases are presented to illustrate this orthopedic technique.
Assuntos
Má Oclusão/terapia , Desenvolvimento Maxilofacial , Aparelhos Ortodônticos Funcionais , Dimensão Vertical , Cefalometria , Criança , Articuladores Dentários , Humanos , Masculino , Mandíbula/crescimento & desenvolvimento , Modelos Dentários , Dente Molar , Desenho de Aparelho OrtodônticoRESUMO
This case report demonstrates the treatment of a Class III malocclusion, in a twelve-year-old girl, using a unique combination of a removable functional appliance, the "four-way sagittal" appliance and fixed appliance therapy. Efficient and effective correction of malocclusion was attained, following use of the "four-way sagittal" appliance. This appliance was designed on the Denar Witzig articulator, a powerful instrument in providing the clinician with a three-dimensional perspective plus the ability of changing the location of the TMJ on the articulator. A significant increase in the maxillary length and maxillary width was achieved.
Assuntos
Má Oclusão Classe III de Angle/terapia , Desenho de Aparelho Ortodôntico , Aparelhos Ortodônticos Funcionais , Cefalometria , Criança , Estimulação Elétrica , Feminino , HumanosRESUMO
Previous clinical and in vitro studies have shown a higher failure rate of composite resins and conventional glass ionomer cements in primary teeth when compared to permanent teeth. A new generation of light-cured glass ionomer cements (compomers) were suggested to be used as restorative materials for the primary teeth. This study was conducted into two parts. The objective of the first part was to compare shear bond strength of compomers (Compoglass and Dyract) and composite resin (Herculite/Optibond) in both primary and permanent teeth. Buccal and lingual surfaces of extracted sound human primary and permanent molars were ground flat on 600-grit SiC paper and divided into 6 groups of 10 surfaces each. The materials were handled according to the instructions of the manufacturer and placed on to the tooth surfaces via clear plastic tubes of 3 mm in diameter. After light curing for 40 seconds, all samples were thermocycled in water bath of 5 degrees F and 55 degrees F for 500 cycles. The samples were embedded in acrylic resin and sheared with an Instron running at a crosshead speed of 0.5 mm/min. Results (mean shear bond strength) were recorded in MPa. Factorial ANOVA revealed that shear bond strength of Herculite/Optibond in the primary teeth (6.07 +/- 2.63) was significantly lower than that of the permanent teeth (17.61 +/- 4.34) (p < 0.0001), but there was no statistically significant difference of bond strength of Compoglass and Dyract between the primary and the permanent teeth. The results from the first part revealed that no materials tested in the primary teeth could provide a shear bond strength of at least 17.6 MPa as recommended. Thus, the objective of the second part of this study was to evaluate shear bond strength of composite resin (Herculite) using three different dentinal bonding agents (Optibond, One-Step and Amalgambond) in the primary teeth. Methods employed in this part were similar to that of the first part. Results showed that Amalgambond provided significantly higher mean shear bond strength (17.96 +/- 5.77) than One-step (11.79 +/- 4.73) and Optibond (6.07 +/-/- 2.63) as tested by Kruskal-Wallis ANOVA and Mann-Whitney U test (p < 0.0001).
