[Optimize excipients for Yinsang hypoglycemic granules by using multiple indexes].

Optimal excipients were screened by studying the effect of different excipients on the hygroscopicity of the extract, testing polysaccharide in the preparation and blood glucose value. Single factor tests were performed with hygroscopicity, formability and fluidity as the indexes, and the moisture content, granule yield and angle of repose were combined with physical characters of the materials to screen the proportioning and dosage of excipients. Then the critical relative humidity of preferred Yinsang granules were measured. The optimum excipients for Yinsang hypoglycemic granules were mulberry leaf paste-microcrystalline cellulose-mactra veneriformis crude polysaccharides (10∶9∶1.67). The obtained granules had good formability and fluidity, which were not easy to absorb moisture for liquefaction, with a critical relative humidity of 73%. This formation process was reasonable and feasible, suitable for industrial production, which can significantly improve hygroscopicity and liquefaction properties of extracts, improve stability of Yinsang granules, and provide reference for screening of excipients for other preparations.

[Three-dimensional finite element analysis of one-piece computer aided design and computer aided manufacture involved zirconia post and core].

OBJECTIVE: To analyze the biomechanics trait of one-piece computer aided design and computer aided manufacture (CAD/CAM) zirconia post and core by the Three-dimensional finite element. METHODS: The Three-dimensional finite element models of three upper central incisors restored with one-piece CAD/CAM zirconia post and core (group 1), refabricated zirconia post and hot-pressed porcelain core (group 2), and cast gold alloy post and core (group 3) were built by geometry method respectively. 100 N vertical loading through the central incisor models long axis and 100 N loading along directing at an angle of 45° with the models long axis were used to imitate the central incisor stress state in biting and mandible physiological protraction movement. RESULTS: Under vertical loading, the restored teeth without dentin ferrule, the maximum Von-Mises stress value of the tooth root in group 1 was the least(11.02 N), which was the largest (13.17 N)in group 2. The stress became weaker from the upper to the lower of the tooth root. The maximum Von-Mises stress value of the tooth root, post and core became smaller while the restored teeth with the 2.0 mm high dentin ferrule. Under directing at an angle of 45° loading, without the design of dentin ferrule in the restored teeth, the maximum Von-Mises stress value of the post and core in group 1 was the greatest(20.45 N), while that stress of post and core in group 3 was the smallest(13.61 N). With 2.0 mm high dentin ferrule design in the restored teeth, the tooth root stress became weaker. The maximum Von-Mises stress value of the tooth root was the greatest (14.10 N) in group 3, but which was the lowest (13.38 N) in group 1. CONCLUSION: The results of the Three-dimensional finite element analysis infers that one-piece zirconia post and core restoration is more beneficial to disperse the bite force than the prefabricated zirconia post and the cast gold alloy post and core. The one-piece of zirconia post and core is good to protect the teeth and keep the restoration intact.

[Comparative research for micro-push-out bond strengths of glass fiber posts treated by poly-dopamine or silane coupling agent].

OBJECTIVE: To evaluate the micro-push-out bond strengths of prefabricated glass fiber posts with poly-dopamine functionalized to root dentin using resin cements, contrasted with silane treatment. METHODS: In the study, 30 glass fiber posts were randomly divided into 3 groups (10 posts in each group) for different surface treatments. Group 1, treated with poly-dopa; Group 2, treated with silane coupling agent for 60s; Group 3, no surface treatment (Control group). The 30 extracted human, single-rooted teeth were endodontically treated and a 9 mm post space was prepared in each tooth with post drills provided by the manufacturer. Following post cementation, the specimens were stored in distilled water at 37 °C for 7 days. The micro-push-out bond strengths were tested using a universal testing machine (0.5 mm/min), and the failure modes were examined with a stereomicroscope. The data of the three groups were statistically analyzed using the one-way ANOVA test(α= 0.05). RESULTS: The bond strengths were (7.909 ± 1.987) MPa for Group 1, (5.906 ± 0.620) MPa for Group 2, and 4.678 ± 0.910 MPa for Group 3. The bond strength of poly-dopamine group was significantly higher than that of the silane group (P<0.05). CONCLUSION: Contrasted with silane treatment, surface poly-dopamine functionalization was confirmed to be a more reliable method for improving the bond strength of resin luting agents to fiber posts.

Novel method of fabricating individual trays for maxillectomy patients by computer-aided design and rapid prototyping.

PURPOSE: Making impressions for maxillectomy patients is an essential but difficult task. This study developed a novel method to fabricate individual trays by computer-aided design (CAD) and rapid prototyping (RP) to simplify the process and enhance patient safety. MATERIALS AND METHODS: Five unilateral maxillectomy patients were recruited for this study. For each patient, a computed tomography (CT) scan was taken. Based on the 3D surface reconstruction of the target area, an individual tray was manufactured by CAD/RP. With a conventional custom tray as control, two final impressions were made using the different types of tray for each patient. The trays were sectioned, and in each section the thickness of the material was measured at six evenly distributed points. Descriptive statistics and paired t-test were used to examine the difference of the impression thickness. SAS 9.3 was applied in the statistical analysis. Afterwards, all casts were then optically 3D scanned and compared digitally to evaluate the feasibility of this method. RESULTS: Impressions of all five maxillectomy patients were successfully made with individual trays fabricated by CAD/RP and traditional trays. The descriptive statistics of impression thickness measurement showed slightly more uneven results in the traditional trays, but no statistical significance was shown. A 3D digital comparison showed acceptable discrepancies within 1 mm in the majority of cast areas. The largest difference of 3 mm was observed in the buccal wall of the defective areas. Moderate deviations of 1 to 2 mm were detected in the buccal and labial vestibular groove areas. CONCLUSIONS: This study confirmed the feasibility of a novel method of fabricating individual trays by CAD/RP. Impressions made by individual trays manufactured using CAD/RP had a uniform thickness, with an acceptable level of accuracy compared to those made through conventional processes.

Effect on push-out bond strength of glass-fiber posts functionalized with polydopamine using different adhesives.

PURPOSE: To evaluate the push-out bond strengths of prefabricated glass-fiber posts (Beijing Oya Biomaterials) with polydopamine functionalized to root dentin using two different resin cements (Paracore and RelyX Unicem) in different root regions (cervical, middle, and apical). MATERIALS AND METHODS: Forty extracted human, single-rooted teeth were endodontically treated and a 9-mm post space was prepared in each tooth with post drills provided by the manufacturer. Specimens were then randomly assigned into four groups (n = 10 per group), depending on the adhesive system and post surface treatment used: group IA (Paracore + polydopamine); group IB (Paracore + control); group IIA (RelyX Unicem + polydopamine); group IIB (RelyX Unicem + control). Following post cementation, the specimens were stored in distilled water at 37°C for 7 days. The push-out test was performed using a universal testing machine (0.5 mm/ min), and the failure modes were examined with a stereomicroscope. Data were statistically analyzed using twoway ANOVA (p = 0.05). RESULTS: Bond strengths (mean ± SD) were: 7.909 ± 3.166 MPa (group IA), 4.675 ± 2.170 MPa (group IB), 8.186 ± 2.766 MPa (group IIA), 4.723 ± 2.084 MPa (group IIB). The bond strength of polydopamine groups was significantly higher than one of the control groups (p < 0.0001). No significant difference was found in the micro push-out bond strengths between the two resin cement groups or the root regions (p > 0.05). Stereomicroscopic analysis showed a higher percentage of adhesive than cohesive failures in all groups. CONCLUSION: Surface polydopamine functionalization was confirmed to be a reliable method for improving the bond strength of resin luting agents to fiber posts. The bond strength of Paracore to fiber posts was not significantly different from that of RelyX Unicem, and considering its convenient application, Paracore can be recommended.

The adhesive strength and initial viscosity of denture adhesives.

OBJECTIVE: To examine the initial viscosity and adhesive strength of modern denture adhesives in vitro. MATERIALS AND METHODS: Three cream-type denture adhesives (Poligrip S, Corect Cream, Liodent Cream; PGS, CRC, LDC) and three powder-type denture adhesives (Poligrip Powder, New Faston, Zanfton; PGP, FSN, ZFN) were used in this study. The initial viscosity was measured using a controlled-stress rheometer. The adhesive strength was measured according to ISO-10873 recommended procedures. All data were analyzed independently by one-way analysis of variance combined with a Student-Newman-Keuls multiple comparison test at a 5% level of significance. RESULTS: The initial viscosity of all the cream-type denture adhesives was lower than the powder-type adhesives. Before immersion in water, all the powder-type adhesives exhibited higher adhesive strength than the cream-type adhesives. However, the adhesive strength of cream-type denture adhesives increased significantly and exceeded the powder-type denture adhesives after immersion in water. For powder-type adhesives, the adhesive strength significantly decreased after immersion in water for 60 min, while the adhesive strength of the cream-type adhesives significantly decreased after immersion in water for 180 min. CONCLUSION: Cream-type denture adhesives have lower initial viscosity and higher adhesive strength than powder type adhesives, which may offer better manipulation properties and greater efficacy during application.

[Fracture resistance of teeth restored with one-piece computer aided design and manufacture zirconia posts and cores: an in vitro study].

OBJECTIVE: To compare the fracture resistance of endodontically-treated teeth restored with prefabricated zirconia posts or one-piece computer aided design and computer aided manufacture (CAD/CAM) zirconia posts and cores, and unrestored endodontically-treated teeth. METHODS: Recently extracted human maxillary central incisors (n = 36) were endodontically treated and divided into three groups (n = 12 each): group 1 was restored with prefabricated zirconia posts (Comospost) and hot pressed ceramic cores; group 2 restored with one-piece CAD/CAM zirconia posts and cores; group 3 not restored. The teeth were fixed in a universal load-testing machine; a compressive load was applied at 135 degrees to the long axis of each tooth at a crosshead speed of 1 mm/min until fracture. One-way analysis of variance (Student-Newman-Keuls) was used to determine the significance of the differences in failure load between the groups. RESULTS: The mean fracture loads were (311.75 ± 70.12) N, (423.83 ± 54.58) N and (736.33 ± 82.91) N, respectively. The unrestored teeth exhibited significantly higher fracture resistance than the two groups of restored teeth. The teeth restored with one-piece CAD/CAM zirconia posts and cores had higher fracture resistance than the teeth restored with prefabricated zirconia posts and hot pressed ceramic cores (P < 0.001). CONCLUSION: Within the limitations of this study, the root canal-treated teeth restored with one-piece CAD/CAM zirconia posts and cores had a significantly higher failure resistance than the teeth restored with prefabricated zirconia posts. one-piece CAD/CAM zirconia posts and cores can offer some advantages for esthetic prosthodontics.

[Fatigue and fracture resistance of the flared roots restored with computer aided design and computer aided manufacturing glass fiber posts].

OBJECTIVE: To evaluate the fatigue and fracture resistance of the flared roots restored with computer aided design (CAD) and computer aided manufacturing (CAM) glass fiber posts. METHODS: In the study, 32 maxillary central incisors with roots longer than 13 mm were selected and their canals were flared, and the roots were allocated into 4 groups (n=8) by a random number chart: CAD/CAM glass fiber posts, prefabricated quartz fiber posts, cast gold alloy posts, and CAD/CAM zirconia posts. The posts were luted to the roots by resin cement and fabricate zirconia crown for every specimen. An addition-type silicone impression material was used to simulate the periodontal ligament. All the specimens were submitted to 1.2×10(6) cycles loaded with a 49 N force, at 45 degree to the long axis of the teeth simultaneously with 3 000 thermal cycles (5 °C-50 °C-5 °C). After that, the specimens were subjected to a load at a crosshead speed of 1 mm/min in a servo-hydraulic testing machine applied at 45 degree to the long axis of the tooth until fracture. The data were subjected to ANOVA test and the patterns of the failure were examined. RESULTS: After the cycling loading, 4 crowns from prefabricated quartz fiber posts groups were deboned, and no other failure was found after the cycling loading; the fracture strengths of CAD/CAM glass fiber posts group [(441.5± 103.2) N] and cast gold alloy posts group [(462.9±170.0) N] were higher (F=4.613, P<0.05) than those of CAD/CAM zirconia posts group [(284.1±99.0) N] and prefabricated quartz fiber posts group [(315.4±112.3) N]; the entire specimens presented unfavorable failures. CONCLUSION: Although further in vitro and in vivo studies are necessary, the results of this study show that the use of CAD/CAM glass fiber posts and cast gold alloy posts may achieve better outcomes in flared roots than that of CAD/CAM zirconia posts and prefabricated quartz fiber posts.

[Wear test of 4-unit posterior resin bonded fixed partial dentures with non-rigid connector].

OBJECTIVE: The aim of this study was to test the difference of fatigue longevity between the 4-unit posterior resin-bonded fixed partial dentures (RBFPD)with non-rigid connector and rigid connector,a wear test to stimulate masticatary function was used. METHODS: Extracted intact human teeth were used to prepare specimens,a first premolar and a second molar as the abutment teeth with a space equivalent to a second premolar and a first molar. Ten specimens were seperated into two groups randomly. The control group was prepared to receive conventional RBFPDs; in the test group a non-rigid connector was used on the distal side of the first premolar. The specimens were put on the thermocycling and mechanical loading (TCML) chewing simulator until the prostheses were broken,and the loading times were recorded. RESULTS: The loading times of the test group and the control group were respectively (134.34 ± 8.17) ten thousand and (92.58 ± 19.73) ten thousand, there was a significant difference between the test group and the control group (P<0.05) analyzed by independent-samples t test (α=0.05). So that the fatigue longevity of 4-unit posterior RBFPDs with non-rigid connector was greater than that of the rigid connector RBFPDs. CONCLUSION: The non-rigid connector could allow independent movement between the two parts of RBFPD and to decrease the stress between the tooth and the wing, and thus increases the fatigue longevity of long-span RBFPDs.

[Finite element analysis of tooth restored with one-piece of computer aided design and computer aided manufacturing zirconia post-core in three different radiuses].

OBJECTIVE: To compare the stress distribution of teeth restored with one-piece of computer aided design and computer aided manufacturing (CAD/CAM) zirconia post-cores in three different radiuses. METHODS: Constructing the 2D finite element models of the standard maxillary central incisal restored by one-piece of CAD/CAM zirconia post-cores and all ceramic crowns, the radius of post was 1.5 mm, 2.0 mm and 2.5 mm respectively. Two tooth root types with or without the ferrule were constructed and there were 6 models in general. Group 1:100 N force loading to the restored teeth through the long axle of teeth and veritical the incisal edge. Group 2: 100 N inclined force loading beneath the incisal edge 2.0 mm by 45° cross the long axle of teeth in the palate side. The stress distribution characteristic of post-cores and teeth roots were analysed. RESULTS: In veritical loading, the stress distribution of one-piece of CAD/CAM zirconia post-core with 2.0 mm radius was better distributed than the two others, The stress concentration of teeth roots locate at the root canal wall where the end of the post exists, which increased with the wider radius of the post-core. In 45° inclined loading, the maximum stress of the zirconia post-core and the teeth root was more than three times of which in vertical loading. In post-cores, the stress concentration was in the labia middle 1/3 of the post. In teeth roots, the stress concentration located at the lateral wall in the post end and the area of the apical foramen. The stress of the post-cores and teeth roots was decreasing in the teeth root with a 2.0 mm ferrule. CONCLUSION: 2.0 mm radicus of the one-piece of CAD/CAM zirconia post-core is a better choice in clinic. There should be a conical degree in the teeth roots preparing for one-piece of CAD/CAM zirconia post-core restoration. The force of protrusive movement has a greater influence on the post-core and teeth roots. The area of apical may be apt to break in overloading.

[All-ceramic resin bonded fixed partial denture made of IPS hot-pressed casting porcelain restore anterior missing teeth: a three years clinical observation].

OBJECTIVE: To clinic observation of IPS Empress2 and IPS e.max all ceramic resin bonded fixed partial dentures used in one anterior teeth lost in upper jaw or less than two anterior tooth lost in lower jaw. METHODS: 22 patients, 26 restorations had been made, which included 16 single-retainer all ceramic resin bonded fixed partial dentures and 10 two-retainers all ceramic resin bonded fixed partial dentures. Secondary caries of the abutments, shade in the margin of the retainers and the integrity of the restorations had been observed at 3 months, 6 months, 1 year, 2 years and 3 years after all ceramic resin bonded fixed partial dentures having been bonded. RESULTS: In the 3 years of clinic observation of the anterior all ceramic resin bonded fixed partial dentures, 1 two-retainers restoration lost bond after it had been made for 3 months, a retainer of one two-retainers restoration was broken after 6 months, but they are still used after modified as one-retainer all ceramic resin bonded fixed partial dentures, 1 two-retainers restoration lost bond two year later, It was integrity and re-bonded again that was still stable. No secondary carries and no shade in margin of the retainers had been found. Their color matches with the nature teeth excellently. The success rate was 88.5%. CONCLUSION: IPS Empress 2 and IPS e.max all ceramic resin bonded fixed partial dentures should be a good selection in one or two teeth lose in anterior jaws.

Use of a CAD/CAM-fabricated glass fiber post and core to restore fractured anterior teeth: A clinical report.

Prefabricated glass fiber posts are widely used; however, their shape cannot be changed and they can be unsuitable for severely damaged teeth with wide root canals. This clinical report describes a procedure for restoring a severely damaged anterior tooth with a customized 1-piece glass fiber post and core, fabricated using a CAD/CAM system. This 1-piece glass fiber post and core adapts better to the root canal than a prefabricated glass fiber post, and reduces the cement layer thickness. Furthermore, it does not require the use of a composite resin foundation.

[Restore two posterior teeth with modified resin-bonded-bridge].

OBJECTIVE: To restore two posterior teeth with resin-bond-bridge with attachments. METHODS: Twenty patients were selected with two adjacent posterior teeth missing and the opposite teeth were natural teeth. The mean age was 45.6 years old, 9 male and 11 female. The maxillary cases were 12 and mandibules case were 8. The female part of attachment was attached with the retainer on the bicuspid teeth; the male part was attached with the pontic. After try-in, the two parts were adhered to the abutments separately and joined by the attachment. RESULTS: The mean survival time of the 20 cases was 28.8 months, and the max was 42 months. In only one case the posterior part debonded, and it resumed being used after rebonding. CONCLUSION: In recent years the successful rate of resin-bond-bridge has got close to that of the traditional bridge. Most RBB were used to restore the single missing tooth. Now RBB with non-rigid connector can restore two missing teeth. When the teeth get stress, the directions of stress are different. The longer span of RBB with rigid connector, the bigger interbutment stress on the adhere layer. With the non-rigid connector the stress between the retainer and the adhesive layer can be reduced. Our clinic treatment showed that this kind of method got good results and even the service time was not very long.

[Experimental mechanics analysis of posterior galvano-ceramic bridges made by Ni-Cr pontic fired bonding galvano caps].

OBJECTIVE: To measure the fracture strength of the posterior galvano-ceramic bridges made by Ni-Cr pontic fired bonding galvano caps with highly temperature-resistant adhesive and to provide reference data for clinical application. METHODS: A standard low dental cast was achieved with 46 missing. Five posterior galvano-ceramic bridges made by Ni-Cr pontic fired bonding galvano caps, with abutments being 47 and 45. The low dental cast was fixed on the panel of the universal testing machine, vertical load given on the central of the pontic as the velocity of 2 mm/min. RESULTS: The fracture strength of the posterior galvano-ceramic bridges made by Ni-Cr pontic fired bonding galvano caps was (877.00+/-126.53) N, the fracture strength of the metal frame was (1,448.94+/-51.02) N. CONCLUSION: Posterior galvano-ceramic bridges made by Ni-Cr pontic fired bonding galvano caps could endure the normal human occlusal force.

The evaluation of the carbon fiber post system on restoration of teeth defect in children.

BACKGROUND: Post and post-core systems are used to restore extensively damaged teeth. Among these systems, cast alloy post and core, prefabricated threaded alloy post and prefabricated simple alloy post are most frequently applied in China nowadays. In Europe and North America a combined application of the fiber post, resin-core and crown has been applied to restore seriously destructed teeth with satisfactory results in recent years. This study was intended to evaluate the clinical effect of carbon fiber post system on restoration of child anterior tooth defect after root canal therapy, based on 3 - 5 years' observation. METHODS: One hundred and six children with incompletely established occlusion were observed and followed for an average of 42 months (ranging from 36 to 60 months). Eighty-five upper teeth and forty-one lower teeth were restored with carbon fiber post system and composite jacket crown. Periodic check-up was conducted for periodontal condition and restoration effect. RESULTS: One hundred and twenty-one (96.2%) restorations were successful. Four jacket crowns (3.0%) were lost. One tooth (0.8%) had slight gingival inflammation. Tooth root or post fracture and gingival stain were not observed. X-ray showed there was no obvious change in aspects including the width of periodontal membrane, the density of alveolar bone and the height of alveolar ridge crest. CONCLUSIONS: Carbon-fiber post system can satisfy the clinical requirements of young patients who have residual anterior crown and root caused by trauma or caries, and have incomplete occlusion and have completed root canal therapy. This system helps realize good esthetic result for patients and easy practice for dentists. Carbon fiber post is safe and convenient, especially for sick children.

Influence of different post core materials on the color of Empress 2 full ceramic crowns.

BACKGROUND: For esthetic consideration, dentin color post core materials were normally used for all-ceramic crown restorations. However, in some cases, clinicians have to consider combining a full ceramic crown with a metal post core. Therefore, this experiment was conducted to test the esthetical possibility of applying cast metal post core in a full ceramic crown restoration. METHODS: The color of full ceramic crowns on gold and Nickel-Chrome post cores was compared with the color of the same crowns on tooth colored post cores. Different try-in pastes were used to imitate the influence of a composite cementation on the color of different restorative combinations. The majority of patients could not detect any color difference less than DeltaE 1.8 between the two ceramic samples. So, DeltaE 1.8 was taken as the objective evaluative criterion for the evaluation of color matching and patients' satisfaction. RESULTS: When the Empress 2 crown was combined with the gold alloy post core, the color of the resulting material was similar to that of a glass fiber reinforced resin post core (DeltaE = 0.3). The gold alloy post core and the try-in paste did not show a perceptible color change in the full ceramic crowns, which indicated that the color of the crowns might not be susceptible to change between lab and clinic as well as during the process of composite cementation. Without an opaque covering the Ni-Cr post core would cause an unacceptable color effect on the crown (DeltaE = 2.0), but with opaque covering, the color effect became more clinically satisfactory (DeltaE = 1.8). CONCLUSIONS: It may be possible to apply a gold alloy post core in the Empress 2 full ceramic crown restoration when necessary. If a non-extractible Ni-Cr post core exists in the root canal, it might be possible to restore the tooth with an Empress 2 crown after covering the labial surface of the core with one layer of opaque resin cement.

[A three-year clinical evaluation of galvano-ceramic bridges made by Ni-Cr pontic bonding galvano caps].

OBJECTIVE: To evaluate the clinical effect of galvano-ceramic bridges made by Ni-Cr pontic fired bonding galvano caps with highly temperature-resistant adhesive based on three-year clinical trials. METHODS: A total of 29 galvano-ceramic bridges made by Ni-Cr pontic fired bonding on the galvano caps were used for 26 patients. Abutment teeth plaque indices (PI) were compared according to Silness and Löe standards and their papillary bleeding indices (PBI) according to Mazza standards before restoration and after 36 months' restoration. At the same time, the integrity and marginal fitness of galvano-ceramic bridges were observed. RESULTS: The PBI at abutment teeth were higher than those before restoration, Wilcoxon test revealed significant difference. Their PI were lower than those before restoration, Wilcoxon test revealed significant difference. All the galvano-ceramic bridges were perfect in marginal fitness and color. The rate of integrity was 89.7% in the period of observation. CONCLUSION: Galvano-ceramic bridges made by Ni-Cr pontic fired bonding galvano caps with highly temperature-resistant adhesive hold out good prospects for clinical use in fixed restoration.

Study on pharmacokinetics of 3,4-divanillyltetrahydrofuran in rats by ultra-fast liquid chromatography/tandem mass spectrometry.

3,4-Divanillyltetrahydrofuran is the main active ingredient of nettle root which can increase steroid hormones in the bloodstream for many of bodybuilders. To better understand its pharmacological activities, we need to determine its pharmacokinetic profiles. In this study, a rapid and sensitive ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method has been developed for the determination of 3,4-divanillyltetrahydrofuran in the plasma of rats. Chromatographic separation was performed on a C18 column at 40°C, with a gradient elution consisting of methanol and water containing 0.3% (v/v) formic acid at a flow rate of 0.8mL/min. The detection was performed using an electrospray triple-quadrupole MS/MS via positive ion multiple reaction monitoring mode. The lower limits-of-quantification determined were 0.5ng/mL. The intra- and inter-day precision (RSD%) was found to be within 15% and the accuracy (RE%) ranged from -4.0% to 7.0%. This simple yet sensitive method was fully validated and could be successfully applied to the study on pharmacokinetics of 3, 4-divanillyltetrahydrofuran.

Effect on the bond strengths of glass fiber posts functionalized with polydopamine after etching with hydrogen peroxide.

UNLABELLED: This paper evaluated the push-out bond strengths of glass fiber posts with poly-dopamine (poly-dopa) functionalized after etching with H2O2. Forty extracted human, single-rooted teeth were endodontically treated and a 9-mm post space was prepared in each tooth with post drills provided by the manufacturer. Specimens were randomly assigned into four groups (n=10 per group), depending on post surface treatment used: group C (control); group D (poly-dopa); group H (H2O2); and group HD (H2O2+poly-dopa). The push-out test was performed using a universal testing machine. RESULTS: Bond strengths (MPa) were as follows: 4.678±0.911 (group C); 7.909±1.987 (group D); 6.519±0.893 (group H); and 9.043±1.596 (group HD). The bond strength of the resin cement to posts functionalized with poly-dopa was not affected by H2O2 pre-treatment, while conditioning using H2O2+poly-dopa resulted in higher bond strengths than H2O2 treatment only. Compared to H2O2 treatment, the bond strength of poly-dopa conditioning was superior.

[Two years clinical observation of anterior all zirconia ceramic resin bonded fixed partial dentures].

OBJECTIVE: To observe the restoration effect of anterior all zirconia ceramic resin bonded fixed partial dentures, and to find a new fixed restorative method for restoring one or two missing anterior teeth. METHODS: Twenty-nine missing anterior teeth from twenty-three patients were restored with all zirconia ceramic resin bonded fixed partial dentures, and restorations were devided in to two groups according to the number of retainers, i.e. the single-retainer group and the two-retainer group. The integrity, secondary caries, marginal shade and color match of the restorations were evaluated with the standard of American Public Health Association (APHA). The average period of observation was 22 months. RESULTS: One restoration from the two-retainer group failed, two restorations from the single-retainer group failed. The shade of two restorations were evaluated as discernable whiter compared to adjacent teeth. There was no secondary caries and marginal shade. The two year success rate of anterior all zirconia ceramic resin bonded fixed partial dentures was 90% (26/29). CONCLUSIONS: All zirconia ceramic resin bonded fixed partial dentures used for less than two anterior missing teeth can achieved definite aesthetic effect and physiologic function. It was a new type of fixed restoration for anterior missing teeth. However, to determine long-term result of this restoration more data are needed.