两种粘接剂对氧化锆全瓷冠粘接效果的比较

目的 比较树脂加强型玻璃离子和自粘接树脂型水门汀粘接剂对氧化锆全瓷冠的临床粘接效果.方法 选取66例患者100颗需要进行氧化锆全瓷冠修复的患牙,随机分为两组(n=50),分别采用3M RelyXTMLuting树脂加强型玻璃离子粘固剂(RelyX L组)和3M RelyXTM U200通用自粘接树脂水门汀(RelyX U组)粘接.两年后复查,检查修复体的固位情况及边缘密合性,比较两组修复的成功率.结果 RelyX L组修复成功率98.0％;RelyX U组修复成功率100.0％,两组间差异无统计学意义.结论 在进行氧化锆全瓷冠修复时,采用树脂加强型玻璃离子和自粘接树脂型水门汀粘接剂均能取得良好的临床粘接效果.     

In vitro retentive strength of zirconium oxide ceramic crowns using different luting agents

STATEMENT OF PROBLEM: In contrast to gold crowns, in vitro determination of the retentive strength of all-ceramic crowns is more difficult because components allowing connection to testing apparatus are not as easily integrated into the all-ceramic material. Nevertheless, retentive strength data are crucial for obtaining information about the potential clinical performance of luting cements for all-ceramic restorations. Therefore, a new in vitro model was necessary to evaluate the retentive strength of all-ceramic crowns. PURPOSE: The purpose of this in vitro study was to determine the retentive strength of 4 resin-cement systems, a compomer, a glass-ionomer cement, a resin-modified glass-ionomer cement, and a self-adhesive resin for luting zirconium oxide ceramic crowns. MATERIAL AND METHODS: One-hundred-twenty extracted human teeth were randomly divided into 12 groups (n = 10) and prepared in a standardized manner (5-degree taper, 3-mm occlusogingival height). All-ceramic crowns (Lava) were fabricated in a standardized manner for each tooth. The following cements and corresponding bonding regimens were used to lute the crowns to the teeth according to manufacturers' recommendations: CO, Compolute/EBS Multi; CO/RT, Compolute/EBS Multi/Rocatec; CB, Superbond C and B; CB/RT, Superbond C and B/Rocatec; CB/PL, Superbond C&B/Porcelain Liner M; PA, Panavia F; DC, Dyract Cem Plus/Xeno III; CH/PL, Chemiace II/Porcelain Liner M; RL, RelyX Luting, K/C, Ketac Cem/Ketac Conditioner; K, Ketac Cem; and RU, RelyX Unicem. After thermal cycling (5000 cycles, 5 degrees C-55 degrees C), the outer surfaces of the cemented zirconium oxide ceramic crowns were treated (Rocatec) to improve bonding and then placed into a low-shrinkage epoxy resin block (Paladur). The block/crown and tooth components for each specimen were connected to opposing ends of a universal testing machine so that crown retention could be measured. Crowns were removed from teeth along their path of insertion. The retentive surface area (mm 2 ) was determined individually for each tooth. Statistical analyses were performed using the Wilcoxon exact test, (alpha =.05) and a Bonferroni correction (alpha =.001). RESULTS: The median (minimum/maximum) retentive strength values (MPa) were as follows: CO, 1.7 (0.6/4.3); CO/RT, 3.0 (1.3/5.4); CB, 4.8 (3.7/7.9); CB/RT, 8.1 (4.2/12.7); CB/PL, 5.3 (3.7/10.2); PA, 4.0 (3.3/5.1); DC, 3.3 (2.1/5.6); CH/PL, 4.0 (1.3/6.3); RL, 4.7 (2.8/6.6); K/C, 1.8 (0.6/2.3); K, 1.9 (0.2/4.5); and RU, 4.8 (2.5/6.7). Superbond C&B (+ Rocatec) specimens showed the highest median retentive strength, but were not significantly different from Superbond C&B without Rocatec pretreatment of the all-ceramic crown's inner surface. Compolute specimens also did not benefit significantly from the Rocatec pretreatment. Within the materials used without pretreatment of the ceramic, Superbond C&B, Panavia, Dyract Cem Plus, RelyX Luting, and RelyX Unicem showed the highest median retentive strength values and were not significantly different. CONCLUSION: Within the conditions of this study, the compomer-cement, the resin-modified glass-ionomer cement, and the self-adhesive resin luting agent had the same level of retentive quality as the resin luting agents, Superbond C&B, and Panavia. Rocatec pretreatment of the ceramic surface did not improve the retentive strengths of Compolute and Superbond C&B.     

三种粘接材料对种植牙冠短期固位和可拆卸性影响的研究

目的:比较玻璃离子、聚羧酸锌和Premier暂时性树脂三种水门汀对粘结固位种植牙冠短期固位和可拆卸性的影响,指导临床选择种植固定义齿的粘接剂。方法:在ITI标准颈纯钛基台上制作前磨牙镍铬金属冠9个,分别用玻璃离子、聚羧酸锌、Premier暂时性树脂三种水门汀粘结于基台上。通过拉伸试验和去冠器冲击试验两种取冠方法测试牙冠脱位所需要的最大载荷值和震动次数。结果:拉伸试验取冠平均脱位载荷值:聚羧酸锌水门汀[(200.28±38.68)N]、玻璃离子水门汀[(137.945±46.720)N]、Premier暂时性粘接树脂水门汀[(103.708±23.727)N]。聚羧酸锌水门汀与玻璃离子水门汀、Premier暂时性树脂水门汀的差异有统计学意义(P<0.05),玻璃离子水门汀与Premier暂时性树脂水门汀的差异无统计学意义(P>0.05)。去冠器取冠平均脱位震动次数:Premier暂时性树脂水门汀(17.667±4.055次)、聚羧酸锌水门汀(3.222±1.474次)、玻璃离子水门汀(1.778±0.786次)。Premier暂时性树脂水门汀与聚羧酸锌水门汀、玻璃离子水门汀的差异有统计学意义(P<0.05);聚羧酸锌水门汀与玻璃离子水门汀的差异无统计学意义(P>0.05)。结论:聚羧酸锌水门汀有较大的粘接力和较好的可拆卸性,能满足粘接固位种植牙冠的固位要求;玻璃离子水门汀有较好的可拆卸性,但粘接力中等;专用种植粘接水门汀Premier粘接力中等,但可拆卸性较差。     

Influence of two different cement space settings and three different cement types on the fit of polymer-infiltrated ceramic network material crowns manufactured using a complete digital workflow

Clinical Oral Investigations - The study evaluates the influence of two spacer settings and three resin luting materials on the marginal and internal fit of polymer-infiltrated ceramic network...     

Modified tricalcium silicate cement formulations with added zirconium oxide

Objectives

This study aims to investigate the effect of modifying tricalcium silicate (TCS) cements on three key properties by adding ZrO₂.

Materials and methods

TCS powders were prepared by adding ZrO₂ at six different concentrations. The powders were mixed with 1 M CaCl₂ solution at a 3:1 weight ratio. Biodentine (contains 5 wt.% ZrO₂) served as control. To evaluate the potential effect on mechanical properties, the mini-fracture toughness (mini-FT) was measured. Regarding bioactivity, Ca release was assessed using ICP-AES. The component distribution within the cement matrix was evaluated by Feg-SEM/EPMA. Cytotoxicity was assessed using an XTT assay.

Results

Adding ZrO₂ to TCS did not alter the mini-FT (p = 0.52), which remained in range of that of Biodentine (p = 0.31). Ca release from TSC cements was slightly lower than that from Biodentine at 1 day (p > 0.05). After 1 week, Ca release from TCS 30 and TCS 50 increased to a level that was significantly higher than that from Biodentine (p < 0.05). After 1 month, Ca release all decreased (p < 0.05), yet TCS 0 and TCS 50 released comparable amounts of Ca as at 1 day (p > 0.05). EPMA revealed a more even distribution of ZrO₂ within the TCS cements. Particles with an un-reacted core were surrounded by a hydration zone. The 24-, 48-, and 72-h extracts of TCS 50 were the least cytotoxic.

Conclusions

ZrO₂ can be added to TCS without affecting the mini-FT; Ca release was reduced initially, to reach a prolonged release thereafter; adding ZrO₂ made TCS cements more biocompatible.

Clinical relevance

TCS 50 is a promising cement formulation to serve as a biocompatible hydraulic calcium silicate cement.

     

Marginal seal of injection-molded ceramic crowns cemented with three adhesive systems

This in vitro investigation evaluated the marginal seal of an injection-molded ceramic crown system used in combination with three adhesive luting systems. One of these systems was a glass-ionomer cement and the other two were based on composite resin materials. One of the latter materials is claimed by the manufacturer to bond to tooth structure and also to porcelain. The final luting material was used in conjunction with a commercially available porcelain bonding system and specific dentin bonding pretreatments. Following thermocycling, the marginal seal of the crowns was tested by use of a chemical marker intrusion technique. The extent of leakage along the sectioned crown/luting agent/tooth structure interfaces was recorded by using digital imaging microscopy. Minimal microleakage was demonstrated with the composite luting cement used in association with specific porcelain and dentin bonding pretreatments.     

Simplified cementation of lithium disilicate crowns: Retention with various adhesive resin cement combinations

Statement of problem

A composite resin cement and matching self-etch adhesive was developed to simplify the dependable retention of lithium disilicate crowns. The efficacy of this new system is unknown.

Retention,marginal leakage,and cement solubility of provisional crowns cemented with temporary cement containing stannous fluoride

PURPOSE: This in vitro study investigated the (1) retention and microleakage of provisional crowns cemented with temporary cements to which stannous fluoride (SnF2) was added, and (2) solubility of these cements. MATERIALS AND METHODS: Provisional crowns were constructed of acrylic resin with shoulder preparations for 12 molars. The crowns were luted with Tempbond, Tempbond NE, and Freegenol temporary cements, and also with SnF2 added to these cements. Specimens were thermocycled 100 times, stored for 6 days, and immersed in 0.5% basic fuschin. Seven days after cementation, crown removal (retention) tests were conducted. Marginal leakage was assessed using a five-level scale to score dye penetration. Solubility in water of the cements with and without SnF2 was assessed using cement disks. RESULTS: Freegenol was more retentive than the other cements. The incorporation of SnF2 significantly increased the retention capacity of Freegenol and Tempbond NE but had no effect on Tempbond. Tempbond showed significantly higher dye penetration than Freegenol. The addition of SnF2 did not alter the dye penetration of the cements. There were no significant differences in the solubility of the cements. However, the incorporation of SnF2 increased the solubility of Freegenol and Tempbond NE (P < .001) and Tempbond (P < .01). CONCLUSION: The addition of SnF2 increased the retention of temporary crowns cemented with Tempbond NE and Freegenol but did not affect the retention of those cemented with Tempbond. The marginal leakage of crowns cemented with the tested temporary cements with and without the incorporation of SnF2 was similar. However, the addition of SnF2 increased the solubility of the cements.     

The optical effect of composite luting cement on all ceramic crowns

Purpose

To investigate the optical properties of resin-based composite cements and assess their effects on the color of all ceramic crowns.

Material and methods

Optical properties of three cements (Variolink II^®, Esthetic^®, Nexus II^®) were analyzed using disk samples (100 μm and 1.0 mm diameter) based on CIELAB color coordinates L*a*b*C* and opacity index. Empress^® (Ivoclar) and Katana^® (Noritake) crowns were filled with four different shades of die material (IPS die material ST3, ST5, ST9 and Tetric Evo Ceram Bleach XL). The shade of the crowns was measured with each of three shades of composite cement (Chroma, Bleach and Opaque, Esthetic^® cement). ST3 and glycerin served as the control. Color differences were calculated in incisal, body and cervical regions.

Results

In the cervical and body regions, the color change caused by the bleach abutment could not be altered by using different colored cements for the Empress^® and Katana^® crowns. In the cervical region, the color changes effected by the dark brown abutment could be reversed with the bleach luting cement; in the body region this was true only for the Empress^® crown. Neither different abutment colors nor different luting cement shades resulted in perceptible color changes in the incisal regions. Mean ΔE* values in the three areas (incisal, body, cervical) were significantly different (p-value < 0.01); in the cervical and body regions Empress^® mean ΔE* was significantly larger (p < 0.01).

Conclusion

The composite cements evaluated in this study created perceptible color differences with particular combinations of die material, cement and ceramic crown.     

Marginal and internal adaptation of zirconium dioxide ceramic copings and crowns with different finish line designs

The present study evaluated the marginal and internal adaptation of single-tooth zirconium dioxide (ZrO2) ceramic copings or crowns with three different finish line designs. Twenty-four steel dies were prepared for maxillary central incisor crowns with the following finish line designs: shoulder (S), rounded shoulder (RS), and chamfer (C) preparations. Twenty-four standardized ZrO2 ceramic copings were manufactured with a CAD/CAM system (Cercon Smart Ceramics), and the crowns were finalized by veneering with a feldspathic ceramic. Measurements for marginal and internal adaptation were performed at two stages: the copings and the completed crowns. No significant differences were observed between the three groups in terms of marginal discrepancy median value: S, 73/69; RS, 61/60; C, 64/55 (microm). However, significant differences in internal adaptation were widely found among all groups: S, 117/111; RS, 72/75; C, 56/57 (microm). As for intra-group comparisons of marginal and internal adaptation values for all groups, the differences were not significant. It was found that the finish line design seemingly wielded no influence on marginal adaptation of single-tooth ZrO2 ceramic copings and crowns. It was also observed that the marginal and internal adaptation values in the present study were all within the clinically acceptable range.     

Influence of cement type and ceramic primer on retention of polymer-infiltrated ceramic crowns to a one-piece zirconia implant

Statement of problem

The best procedure for cementing a restoration to zirconia implants has not yet been established.

Retention of crowns as affected by film thickness of zinc phosphate cement and taper angle of crowns (author's transl)]

Dependence of the retention of crowns at their axial wall on the film thickness of zinc phosphate cement and the taper angle was investigated. Stainless steel dies, composed of a preparation and an occlusally perforated crown the taper angle of which was 2.9, 5.7, 8.5 and 11.3 degrees respectively (Fig. 1, (a) and (b)), were cemented within three min. after the start of mix with a Shofu Micro Cement having a powder-liquid ratio of 1.5 g/0.5 cc. The thickness of the cement layer at the axial wall was regulated to a given value between 9 and 55 mu through the use of a discrepancy measurer. A Shimazu Autograph tensile test machine was employed to measure 48-hr retention (kg/cm2). The retention of the crowns was strongly dependent on the cement film thickness and the taper angle when the film thickness was below a critical value (15 mu in this experiment), but not when the film thickness was above this value (Fig. 3). This may be explained by the term of mechanical interlocking of either of the unreacted powder grains and the matrix phase in the luting cement, as schematically drawn in Fig. 6. The same findings were more evidently appeared on the semilogarythmic diagram in Fig. 4. In this diagram, the critical value was shown as intersection of two straight lines which could be drawn through all the measurements for four taper angles, using the least squares.     

Simulation of clinical fractures for three different all‐ceramic crowns

Comparison of fracture strength and fracture modes of different all‐ceramic crown systems is not straightforward. Established methods for reliable testing of all‐ceramic crowns are not currently available. Published in‐vitro tests rarely simulate clinical failure modes and are therefore unsuited to distinguish between the materials. The in‐vivo trials usually lack assessment of failure modes. Fractographic analyses show that clinical crowns usually fail from cracks initiating in the cervical margins, whereas in‐vitro specimens fail from contact damage at the occlusal loading point. The aim of this study was to compare three all‐ceramic systems using a clinically relevant test method that is able to simulate clinical failure modes. Ten incisor crowns of three types of all‐ceramic systems were exposed to soft loading until fracture. The initiation and propagation of cracks in these crowns were compared with those of a reference group of crowns that failed during clinical use. All crowns fractured in a manner similar to fracture of the clinical reference crowns. The zirconia crowns fractured at statistically significantly higher loads than alumina and glass‐ceramic crowns. Fracture initiation was in the core material, cervically in the approximal areas.     

Retention and surface changes of zirconia primary crowns with secondary crowns of different materials

Objectives

To evaluate zirconia as a substitute for gold alloy in primary crowns facing secondary crowns manufactured with different materials, in terms of long-term retention force changes, wear, and phase transformation was aimed.

Materials and Methods

A total of 12 groups, each containing six samples, consisting of gold alloy primary crown-electroformed gold secondary crowns (AA), zirconia primary crown-electroformed gold secondary crowns (ZA) and zirconia primary crown-casted non-precious alloy secondary crowns (ZC) with conus angles of 0°, 2°, 4°, and 6° were evaluated. Samples were subjected to 10,000 insertion–separation cycles in artificial saliva and retention force was measured. X-ray diffraction and scanning electron microscope analysis were performed on the sample surfaces.

Results

The highest retention forces were obtained from ZC-0° group (72.09–71.26 N) and the lowest were obtained from ZA-4° (12.73–19.44 N) and ZA-6° (5.36–19.73 N) groups in the beginning and after 10,000 cycles, respectively. Retention force increased as the conus angle decreased. The monoclinic phase ratio of the zirconia primary crowns decreased after the experiments. No wear was observed in zirconia primary crowns except for the ZC-0° and ZC-2° groups. The use of zirconia primary crowns resulted in a less excursive retention force.

Conclusions

A more predictable and less excursive retention force can be obtained using a hard and rigid primary crown material like zirconia.

Clinical Relevance

Despite a lack of knowledge about the aging of zirconia without a veneer layer in the oral environment, zirconia primary crowns are more advantageous in terms of retention force development and wear.     

Retention force measurement of telescopic crowns

This study deals with the determination of the retentive force between primary and secondary telescopic crowns under clinical conditions. Forty-three combined fixed–removable prostheses with a total of 140 double crowns were used for retention force measurement of the telescopic crowns prior to cementation. The crowns had a preparation of 1–2°. A specifically designed measuring device was used. The retentive forces were measured with and without lubrication by a saliva substitute. The measured values were analyzed according to the type of tooth (incisors, canines, premolars, and molars). Additionally, a comparison between lubricated and unlubricated telescopic crowns was done. As maximum retention force value 29.98 N was recorded with a telescopic crown on a molar, while the minimum of 0.08 N was found with a specimen on a canine. The median value of retention force of all telescopic crowns reached 1.93 N with an interquartile distance of 4.35 N. No statistically significant difference between lubricated and unlubricated specimens was found. The results indicate that retention force values of telescopic crowns, measured in clinical practice, are often much lower than those cited in the literature. The measurements also show a wide range. Whether this proves to be a problem for the patient’s quality of life or not can however only be established by a comparison of the presented results with a follow-up study involving measurement of intraoral retention and determination by e.g. oral health impact profile.     

Evaluation of Berlin jacket crowns compared with plastic or ceramic jacket crowns]

34 jacket crowns of ceramic material, of plastic and of a combination plastic-ceramic material (Berlin jacket crowns), respectively, were clinically re-examined using a uniform scoring scale. The results obtained show that the Berlin jacket crowns can be ranked between the ceramic jacket crowns and the plastic jacket crowns.