ABSTRACT
OBJECTIVE: The aims of this study were to evaluate the relationship between the detachment force and bonding resin surface are and to determine the resin bonding surface area that would provide adequate bonding strength with minimum resin volume. METHODS: One hundred and sixty human premolars were randomly divided into 4 groups of 40 teeth each. The diameter of the resin surface area in each group was as follows: group 1, 1.5 mm; group 2, 2.5 mm; group 3, 3.5 mm; and group 4, 4.5 mm. Respond Dead Soft straight (length 0.0175 inch) was used to fabricate the retainers, and Transbond(TM) XT was used to fix the retainers to the tooth surfaces. A pair of teeth was embedded in acrylic blocks for each specimen. Thus, each group comprised 20 samples. Fixed retainers were bonded to the teeth, and vertical force was applied at the middle of wire. The force was measured using a universal testing machine. RESULTS: The mean value of detachment force was the highest for group 4 (102.38 +/- 2.92 N), followed by group 3 (63.54 +/- 2.21 N), group 2 (51.95 +/- 1.61 N), and group 1 (24.14 +/- 1.38 N). CONCLUSIONS: The detachment force of lingual fixed retainers was significantly affected as the area of the resin bonding surface increased. Considering the minimum bonding strength of brackets, a resin bonding surface area with a diameter of 3.5 mm would provide adequate bonding strength.
Subject(s)
Humans , Bicuspid , ToothABSTRACT
Subject(s)
Child , Female , Humans , Bicuspid , Dentigerous Cyst , Mouth , Orthodontic Extrusion , Tooth , Tooth, Deciduous , Tooth, ImpactedABSTRACT
OBJECTIVE: This study aimed to verify the intra-individual reproducibility of the natural head position (NHP) in adult Korean patients in the centric relation (CR) position and to prove the inter-individual variability of the Frankfurt horizontal (FH) plane and sella-nasion (SN) line compared to the true horizontal line (THL). In addition, the study aimed to investigate the correlations between linear measurements from A-point and B-point to the nasion true vertical line (NTVL) and angular measurements from A-point and B-point to the SN line. METHODS: Two lateral cephalograms were taken of 116 subjects (23 males, 93 females) with CR wax bites in a NHP at a one-week interval. RESULTS: Method errors of three variables and intraclass correlation coefficients of six parameters proved the intra-individual reproducibility of NHP (p 0.05), but it was clinically variable (SD 3.89degrees) on the inter-individual level. Conversely, the angle of the SN line to the THL was significantly different from 7degrees (p < 0.05). Very low correlation was found between the linear measurements and angular measurements of A-point and B-point (p < 0.01). CONCLUSIONS: The NTVL could be a useful reference line for assessing the antero-posterior position of the maxilla and mandibleof Korean adult patients in NHP and CR.
Subject(s)
Adult , Humans , Male , Bites and Stings , Centric Relation , Head , MaxillaABSTRACT
Subject(s)
Rabbits , Dexamethasone , Durapatite , Mandible , Osteoblasts , Osteogenesis , Silver Staining , TransplantsABSTRACT
Subject(s)
Aged , Humans , Male , Anesthesia, General , Bicuspid , Epithelium , Incisor , Mandible , Odontogenic Cysts , Periodontal Cyst , Recurrence , TransplantsABSTRACT
Subject(s)
Child , Humans , Basal Cell Nevus Syndrome , Carcinoma, Basal Cell , Early Diagnosis , Hypertelorism , Incisor , Jaw , Megalencephaly , Odontogenic Cysts , Orthodontic Extrusion , RibsABSTRACT
The nonstructural protein 4 (NSP4) of rotavirus encoded by gene 10, plays an important role in rotavirus pathogenicity. In this study, NSP4 gene sequences of human rotaviruses circulating in Seoul, Korea between March 2004 and April 2005 were determined. The nucleotide sequence data indicated that the NSP4 genes of human rotavirus Korean isolates were 750 or 751 bases in length and encoded one open reading frame of 175 amino acids with two glycosylation sites. The NSP4 of Korean isolates exhibited amino acid sequence homologies between 59.4% and 98.9%. The NSP4 of CAU4 and CAU15 showed a high degree of amino acid sequence homologies with NSP4 genotype A viruses, but the NSP4 of CAU5, CAU6, CAU11, CAU14, CAU16 and CAU22 exhibited a high degree of amino acid sequence homologies with NSP4 genotype B viruses. Interestingly, CAU3 and CAU7 showed low degree of amino acid sequence homology with those of currently described NSP4 genotypes A to D and belonged a distinct lineage on the phylogenetic tree. These findings suggests that distinct NSP4 type was circulating among human rotavirus strains in the local community of Seoul and raising intriguing questions regarding possible explanations for new genotype.
Subject(s)
Humans , Amino Acid Sequence , Amino Acids , Base Sequence , Genetic Variation , Genotype , Glycosylation , Herpesvirus 1, Cercopithecine , Korea , Open Reading Frames , Rotavirus , Seoul , Sequence Homology, Amino Acid , VirulenceABSTRACT
Bacillus anthracis is the causative agent of anthrax primarily in animals and rarely in humans. B. anthracis producing 'anthrax toxin', however, could be a major agent of biological warfare. Anthrax toxin is produced from the pXO1 plasmid encoding the lethal toxin (LeTx) consisted of the protective antigen (PA) and the lethal factor (LF). In this study, we tested whether specific antisense oligonucleotide could inhibit the gene expression in B. anthracis. The antisense oligonucleotide was forced into bacterial cells either by lipofection or heat shock method. The expression of LeTx in B. anthracis was analyzed by the Western blot analysis and the MTT assay using to Raw 264.7 cells. The LeTx protein was purified and used for the production of specific antibodies. The expression of LeTx could be confirmed only in B. anthracis strains haboring pXO1 plasmid. B. anthracis treated with the antisense oligonucleotide through heat shock method markedly inhibited the production of PA. In the Western blot analysis, the expression of PA was inhibited from 25 micrometer and was completely inhibited at 50 micrometer of the antisense oligonucleotide. In the MTT assay, the cytotoxicity was reduced to 20% at 20 micrometer of the antisense oligonucleotide. Above results suggest that the antisense technology would be applied for the research on gene function in B. anthracis.