ABSTRACT
OBJECTIVE@#To analyze the relationship between the width of the maxillary anterior teeth and the anterior arch perimeter, to analyze the change rule of the width of the anterior teeth and the anterior arch perimeter, when altered the convexity of the anterior arch, with the width of the maxillary anterior arch keeping constant, and to provide a reliable basis for later digitized and personalized aesthetic analysis of front teeth.@*METHODS@#In the study, 61 front teeth complete and well-arranged models had been selected from the working models after the prostheses in Department of Prosthodontics, Peking University School and Hospital of Stomatology, including 22 male models and 39 female models. A photograph was taken from the occlusal surface of each model using the fixed magnification with a single lens reflex camera. The width of anterior teeth, the width of anterior arch and the convexity of anterior arch had been measured using the Photoshop software. The ratio of the width of the anterior teeth to the width of the anterior arch was calculated. Keeping the width of anterior arch unchanged, the layer free transformation function used to add or decrease the curvature of the anterior arch from 1-5 mm, each circumference of the anterior arch was measured. According to the proportion of their anterior teeth in the anterior arch perimeter, the width of each anterior teeth crown under different convexities of anterior arch was calculated. SPSS 23.0 was used to analyze the ratio of the width anterior teeth to the anterior arch perimeter and correlation between the convexity of the anterior arch and the width of the anterior teeth.@*RESULTS@#The percentages of the median length of the anterior arch in the central incisor, lateral incisor and canine were 36.2%±1.3%, 30.2%±1.5%, and 33.6%±1.4%, respectively. The proportions were normal distributions and not related to the perimeter of the anterior arch. When the width of the anterior arch was constant, there was a positive correlation between the convexity of anterior arch in the range of 5 mm and the width of anterior teeth or the front arch circumference. With each increase or decrease of 1 mm of the convexity of anterior arch, the width of the middle incisor increased or decreased by about 0.18 mm, the half circumference of the anterior arch increased or decreased by about 0.50 mm.@*CONCLUSION@#The width of the anterior teeth in the middle-distal direction remained stable in the anterior arch circumference. Within a certain range, when the width of the maxillary anterior arch remains unchanged, the width of the anterior teeth and the perimeter of the anterior teeth are positively correlated to the convexity of the anterior arch.
Subject(s)
Female , Humans , Male , Cuspid , Dental Arch , Incisor , Maxilla , Odontometry , SoftwareABSTRACT
OBJECTIVE@#To investigate the color stability of infiltrant resin together with three other composites exposed to staining solution.@*METHODS@#Three types of anterior aesthetic composite resins (Filtek Z250, Filtek Z350 XT, and Beautiful Flow Plus F00) and artificial caries with Icon infiltrant resin were used. The samples were randomly divided into two groups (each contained 10 specimens): coffee solution and distilled water immersion for three weeks. Color parameters were deter-mined with the Crystaleye spectrophotometer.@*RESULTS@#Artificial caries lesions infiltrated by Icon showed much higher ΔE than those infiltrated by other aesthetic resins (P<0.05). The discoloration of all the experimental resins and the artificial caries infil-trated with Icon increased with time, but the discoloration on the 1st week was significantly higher than those on the 2nd and 3rd weeks.@*CONCLUSIONS@#Artificial caries infiltrated with Icon was more vulnerable and susceptive to food color than those infiltrated with other aesthetic composite resins.
Subject(s)
Humans , Color , Composite Resins , Dental Caries , Esthetics, Dental , Materials Testing , Surface PropertiesABSTRACT
<p><b>OBJECTIVE</b>To establish a gene-modified embryonic stem (ES; E14.1-2) cell line with hepatoblast differentiation reporter genes, albumin (ALB) and cytokeratin 19 (CK19), labeled to facilitate study of their potential applicability as differentiated hepatoblasts.</p><p><b>METHODS</b>Two expression vectors were constructed, one with the ALB promotor driving the enhanced green fluorescent protein (EGFP) and anti-neomycin genes (pAlb-EGFP), and the other with the CK19 promotor driving the red fluorescence protein and anti-hygromycin genes (pCK19-hCD25-IRES-tdTOMATO). The linearized vectors were electroporated into the E14.1 line, and double reporter genes-modified ES cells (E14.1-2) were selected by neomycin and hygromycin. E14.1-2 hepatoblast differentiation was induced by exposure to growth factors (BMP4 and bFGF) and evidenced by embryoid body formation. Fluorescence-activated cell sorting (FACS) and reverse transcription-polymerase chain reaction (RT-PCR) were used to confirm whether differentiated cells were hepatoblast-like and to quantify the differentiation efficiency.</p><p><b>RESULTS</b>The pAlb-EGFP and pCK19-hCD25-IRES-tdTOMATO vectors were shown to specifically activate ALB and CK19 expression. The E14.1-2 cell line with labeled ALB and CK19 was established, and shown to have pluripotency by RT-PCR detection of pluripotent markers' expression, namely Oct4 and SSEA-1. After 22 days of induction, 21.27% of the differentiated hepatoblasts were detected by FACS as positive for ALB and CK19 expression.</p><p><b>CONCLUSIONS</b>A gene-modified ES cell line was generated with hepatocyte differentiation reporter genes ALB and CK19 labeled. The differentiation of the resultant E14.1-2 line was technically simple to qualify and quantify, and will likely aid future studies of hepatoblast characteristics.</p>