tachment level was changed from 8.67+/-1.72mm to 7.00+/-1.60mm (control); from 8.93+/-2.23mm to 6.00+/-1.92mm (test); and bone probing depth was decreased from 10.20+/-1.90mm to 9.07+/-1.95mm (control); from 10.14+/-2.14mm to 7.43+/-2.06mm (test). This study indicates that treatment of periodontal intrabony defects with EMD is clinically superior to treatment without EMD (OFD alone) in every parameter evaluated. Within the limits of this study, the application of EMD in intrabony defects resulted in clinically significant gain of clinical attachment level and decrease of bone probing depth. And further controlled clinical studies are required to confirm the effectiveness of the EMD in the treatment of various osseous defects.
Dental Enamel*

No abstract available.
Dental Enamel*

No abstract available.
Dental Enamel*

No abstract available.
Dental Enamel* ; Dental Porcelain*

The research was carried out invitro to assess anticaries efficacy of toothpastes. 9 groups of enamel samples were treated with 9 kinds of toothpaste including 8 fluoride-toothpastes (marketed in Vietnam) and 1 placebo (no fluoride). The result of this study showed that fluoride-toothpaste had ability to increase fluoride component of the enamel so it has anticaries efficacy. But the different dentifrice’s anticaries efficacy was also different.
Fluorides ; Dental Enamel

The purpose of this study was to evaluate the feasibility of the combined use of paste resin with sealant as an adhesive of the indirect bonding. The resin bases made of light-cured resin were bonded to the bovine incisors at a distance of 0.0, 0.2 or 0.4 mm using the sealant only or the mixture of sealant and paste resin. Bond strength of each group was measured using universal testing machine. The results were as follows : 1. The bond strength was reduced in both groups as the distance between enamel surface and resin base increased. 2. The bond strength showed no statistical difference between two groups in case the distance between enamel surface and resin base was 0.0 mm. 3. In case the distance between enamel surface and resin base was 0.2 or 0.4 mm, the sealant with paste resin group showed significantly higher bond strength than the sealant only group. The results of the present study indicate that the use of paste resin with sealant may be desirable as an adhesive in indirect bonding, particularly in case a gap is suspected between enamel surface and resin base.
Adhesives* ; Dental Enamel* ; Incisor

Sixty premolars extracted for orthodontic treatment were divided into four groups, and the residual resin was removed with four different rotary finishing instruments at a fixed speed of 18,500+/-300rpm on the low speed handpiece. The instruments were G1; 169L carbide fissure bur, G2; No.2 round bur, G3; No.4 round bur, G4; No.8 round bur. Then, the enamel received a 5-second polishing with a rubber cup and a pumice. To find the extent of loss on the enamel at this point, prophylaxis was done with the rubber cup and a pumice prior to bonding of the bracket(P1) and removal of residual resin by means of appropriate procedure applicable to each resprctive group(P2) followed. The final polishing was done with the rubber cup and pumice(P3), and the enamel surface roughness was measured each by the surface measuring instrument. The whole process was obesrved under a scanning electron microscope to gain the following results : At P2, the enamel surface roughness in G1 showed most smoothly with 2.60+/-0.55microgram; in G2, 3.24+/-0.80microgram; in G3, 3.44+/-0.94microgram; in G4, 3.89+/-0.54microgram, the rougjest. G2 and G3 showed no statistical significance(P>0.05). At P3, the enamel surface roughness in G1 showed most smoothly with 2.29+/-0.47microgram, in G2, 2.44+/-0.56microgram, in G3, 2.44+/-0.58microgram, in G4, 2.92+/-0.43microgram, the roughwst. G1 vs G2, G3, and G2 vs G3 had no statistical significances(P>0.05). In all groups, P2 and P3 showed rougher in surface roughness than P1, and P2 rougher than P3(P<0.01). In a case of 5-second prophylaxis with the rubber cup and the pumice on a virgin, normal enamel. fine scratches were found under the scanning electron microscope. In all four groups, unremovable gouges remained even agter polishing with the rubber and pumice; residual resin was not observed with naked eye when finished with the rubber and pumice, but the resin debris was observed under the scanning electron microscope.
Bicuspid ; Dental Enamel* ; Rubber

The aim of this study was to clarify whether bonding/debondmg procedure will affect the occurance of enamel crack. The frequency of enamel crack was compared between before-bonding and after-debonding on 200 human extracted teeth Each facial surface of the tooth was divided in 9 fragments A presence of crack, which was classified by its direction as vertical, horizontal and oblique crack, was surveyed in each fragment. Number of all cracks in facial surface was 1355 at before-bonding, and 1605 at after-debonding, so it revealed significant increase rate of 18.5%, but compared by fragment, cracks were significantly increased in OC, OD, CC and GC fragments. All kinds of cracks were significantly increased, especially increase rate of oblique crack reached 54.9%. The increase rate of cracks was not superior at any fragment or region, but some evidence was seen in CC fragment. Judging from the above, increase of crack is unavoidable with bonding/debonding procedures.
Dental Enamel* ; Humans ; Tooth*

Previous study had shown the diversities in the propriety for optimal bond strength on the concentration of the etchant. The aim of present study in vitro was to evaluate and compare the shear bond strength of orthodontic brackets to enamel and to measure the depth of etch on the phosphoric acid concentrations. A hundred and seventy six extracted bovine lower centrals were ground to yield flat surfaces and etched by the concentration 0%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% and 85% of phosphoric acid respectively during 60 seconds. The shear bond strength of orthodontic brackets, the depth of etch and surface roughness of the enamel were measured, and scanning electron microscopic observations on the etched enamel surfaces were carried out. The data obtained from the very experiments were processed and statistically analyzed and evaluated. The gradual increase in the depth of etch to enamel as the accretion of the concentration of the phosphoric acid up to 40-50% and decline henceforth were manifested. The surface roughness showed no correlation with the depth of etch, yet moderate correlation with the shear bond strength of brackets. Scanning electron microscopic investigation revealed that morphological patterns of the etched enamel surfaces for 5% to 40% of concentrations were even and homogenous, and those for 50% as well as 60% exhibited the overetched and unhomogenous. The shear bond strengths from 10% to 60% of concentration showed no statistically significant differences. It was suggested that the shear bond strengths at 5% and 70% were sufficient to tolerate the force levels of the ordinary orthodontic treatment notwithstanding to be significantly lower than those from 10% to 60% phosphoric acid solution.
Dental Enamel* ; Orthodontic Brackets*

The aim of this study was to evaluate and compare the microstructural properties and mineralization quality of mesiodens with permanent and primary central incisors.Fifteen mesiodens, permanent and primary central incisors were collected. The enamel rod diameter and enamel thickness were observed and measured using field emission scanning electron microscope (FE-SEM). Chemical composition of the enamel was analyzed using energy dispersive X-ray spectrometer (EDS). The measurements were then assessed using the one-way ANOVA and Tukey test.There was no statistically significant difference in the enamel rod diameter between mesiodens and permanent central incisors. However, enamel rods of primary central incisors were smaller than remaining two groups. The thickness of enamel was thick in order of permanent central incisors, mesiodens, primary central incisors. In the composition analysis using EDS, there was no difference in the Ca/P ratio and Ca/C ratio between mesiodens and permanent central incisors, but small in primary central incisors.In conclusion, the microstructural properties of mesiodens were more similar to those of permanent central incisors compared to primary central incisors. Futher, the mineralization quality of mesiodens did not differ significantly from that of permanent central incisors.
Dental Enamel ; Incisor ; Miners