No abstract available.
Dental Enamel* ; Dental Porcelain*

The purpose of this study is to develope new dental color-space system. Twelve kinds of dental composites and one kind of dental porcelain were used in this study. Disk samples (15 mm in diameter, 4 mm in thickness) of used materials were made and sample's CIE L*a*b* value was measured by Spectrocolorimeter (MiniScan XE plus, Model 4000S, diffuse/8degrees viewing mode, 14.3 mm Port diameters, Hunter Lab. USA). The range of measured color distribution was analyzed. All the data were applied in the form of T### which is expression unit in CNU Cons Dental Color Chart. The value of L* lies between 80.40 and 52.70. The value of a* are between 10.60 and 3.60 and b* are between 28.40 and 2.21. The average value of L* is 67.40, and median value is 67.30. The value of a* are 2.89 and 2.91 respectively. And for the b*, 14.30 and 13.90 were obtained. The data were converted to T### that is the unit count system in CNU-Cons Dental Color Chart. The value of L* is converted in the first digit of the numbering system. Each unit is 2.0 measured values. The second digit is the value of a* and is converted new number by 1.0 measured value. For the third digit b* is replaced and it is 2.0 measured unit apart. T555 was set to the value of L* ranging from 66.0 to 68.0, value of a* ranging from 3 to 4 and b* value ranging from 14 to 16.
Dental Materials* ; Dental Porcelain

No abstract available.
Dental Alloys* ; Dental Porcelain*

ABSTRACT This study aims to compare the effect of fTCP-contained toothpaste in combination with 950 ppm fluoride on primary dentin caries surface to ordinary 1100 ppm fluoride toothpaste by using estimation statistics. Dental caries with deep lesion and dentin exposure from nine primary teeth were cut into two equal parts and randomly divided into two groups in a before-after study. Each group was brushed with one type of toothpaste two times per day for 28 days and rested in artificial saliva. SEM images of cavity bottom surfaces and energy-dispersive X-ray spectrometry (EDX) were used to determine the percentage of calcium (Ca), phosphorus (P), fluoride (F) and oxygen (O) at six continuous measured areas from the surface of the cavity bottom into 45 µm depth before and after brushing. About 95% confidence interval of the mean difference was calculated by performing bootstrap resampling with 5000 resamples followed by comparison analysis. The percentage of Ca, P, F, O was shifted after treatment. There was no difference between the two groups. The SEM images reflected a similar illustration of EDX data. The combination of fTCP and 950 ppm fluoride in toothpaste showed equivalent effectiveness to the 1100 ppm fluoride toothpaste in primary dentin caries.
Fluorosis, Dental ; Dental Caries

A new clinic conception, healthy cosmetic management (HCM), was innovated introduced into diagnose and treatment of patients with high caries risk. The priority of HCM should be given to aesthetic restoration of teeth, taking consideration of the conserving of tissue and pulp of teeth and the balance between health and aesthetics, which may reach to the goal of the individual clinic treatment. HCM includes five steps: 1) caries risk assessment; 2) detection of initial caries; 3) digital aesthetic design; 4) minimally invasive therapy; 5) behavior management of caries and doctor-patient communication pattern. In this article, HCM is introduced into two aspects: process management and clinical protocols, followed by the combination of the clinical practice.
Dental Caries ; Dental Pulp ; Esthetics, Dental ; Humans

The minimal tooth reduction, esthetic appeal and biocompatibility of porcelain laminate veneers have made them one of the mainstream technologies for minimal invasive esthetic dental restorations. Cementation is a crucial step in ensuring retention, marginal seal and influencing the clinical longevity of veneer restorations. Experts from Society of Prosthodontics, Chinese Stomatological Association formulated operational specifications for the cementation of porcelain laminate veneers, so as to standardize the clinical operating procedures, achieve the long-term success of veneer restorations, and promote the application of porcelain laminate veneers.
Cementation ; Dental Porcelain ; Dental Veneers ; Esthetics, Dental

STATEMENT OF PROBLEM: The adjustable dental impression trays were made for being adjusted their width automatically along the width of dental arch. PURPOSE: The purpose of this study was to investigate the best retentive form of adjustable dental impression tray, and so to make it a more satisfactory product. MATERIALS AND METHODS: The eight pairs of adjustable trays were made of ABS(acrylonitrile butadiene styrene) with different distribution of holes and with or without the rim on the border area of them. The experiment was done with the horse-shoe shaped metal plate to pull out the set impression body from the tray, and the tray jig which was made for holding the tray on a lower part of Universal Testing achine(UTM, Zwick Z020, Zwick Co., Germany). After the impression in the tray was allowed to set four minutes, a tensile force was applied at right angles to the tray which had been previously seated on the jig. The force was applied to measure a maximum retentive force by use of a UTM at a constant strain rate of 100mm per minute. A 2-factor analysis of variance (p<.05) was used to determine whether differences existed among distribution of retentive holes and between rim existing and not. RESULTS: 1. The retentive force of the upper and lower resin tray with 2mm holes on the tray border was highest(25.83/24.98kg).(p<.05) 2. As the tray had more retentive holes, it was less retentive. 3. There was no significant difference in the retentive force of the varied hole intervals in the case of distributing all the area.(p>.05) 4. The rimless trays were more retentive generally, than the rimmed trays except 2 case: upper tray group-all area / 2 mm. intervals and lower tray group-margin only / 2 mm. intervals.(p<.05) 5. Most of the adjustable trays were showed higher retentive force than perforated metal tray except the lower group that perforated on the all area at intervals of 2 mm.
Dental Arch

STATEMENT OF PROBLEM: Several domestic dental implants have been developed since dental treatment being implants are increasing and popularized. However, they have not been used in domestic market like imported goods. MATERIAL AND METHODS: This study was carried out to compare domestic and imported implants in aspect of fitness, dental implant fixture and abutment screw using scanning electron microscope. All experiments were performed under dry condition. RESULTS: 1. Only in aspect of relation of dental implant fixture and abutment screw, except only one group with point contact, good fitness was existed. 2. Home products must presevere in their efforts, so as excellent to fit.
Dental Implants

OBJECTIVE: The additional arch length required for leveling (AALL) the curve of Spee (COS) can be estimated by subtracting the two-dimensional (2D) arch circumference, which is the projection of the three-dimensional (3D) arch circumference onto the occlusal plane, from the 3D arch circumference, which represents the arch length after leveling the COS. The purpose of this study was to determine whether the cusp tips or proximal maximum convexities are more appropriate reference points for estimating the AALL. METHODS: Sixteen model setups of the mandibular arch with COS depths ranging from 0 mm to 4.7 mm were constructed using digital simulation. Arch circumferences in 2D and 3D were measured from the cusp tips and proximal maximum convexities and used to calculate the AALL. The values obtained using the two reference points were compared with the paired t-test. RESULTS: Although the 3D arch circumference should be constant regardless of the COS depth, it decreased by 3.8 mm in cusp tip measurements and by 0.4 mm in proximal maximum convexity measurements as the COS deepened to 4.7 mm. AALL values calculated using the cusp tips as reference points were significantly smaller than those calculated using the proximal maximum convexities (p = 0.002). CONCLUSIONS: The AALL is underestimated when the cusp tips are used as measurement reference points; the AALL can be measured more accurately using the proximal maximum convexities.
Dental Occlusion

PURPOSE : The purpose of this study was to develop the radiographic technique for detecting the demineralization which is known as indication of dental caries MATERIALS AND METHODS : This technique was based on the comparing of multiple radiographs which was irradiated by multiple X-ray spectra. For the meaningful comparing, the multiple radiographs were reconstructed to the dosimetrically consistent images using a standard material. The difference of resulting images of same target with multiple spectra represents the difference of response of material as regards the spectra. RESULTS : We have found about 10% of demineralization of dental hard tissues particularly in the proximal region through the analyzing of differences. CONCLUSION : Most intriguing thing in this investigation was that the method to analyze difference shows us to an anatomic structure of dental hard tissues even if absolute values of optical density were excluded during the procedures.
Dental Caries