Impact of Dentinal Tubule Orientation on Dentin Bond Strength

This study aimed to determine the impact of dentinal tubule orientation on dentin bond strength to provide a reference for clinical cavity preparation in resin-bonded restoration. Patients aged 13-16 years were selected, including 18 males and 21 females. Forty-eight human maxillary first premolars from orthodontic extractions were chosen to prepare the test models with the dentinal tubule orientations perpendicular and parallel to the bonding substrate. The test models in the vertical and parallel groups were divided into three groups： total-etching with 20% phosphoric acid, total-etching with 35% phosphoric acid and self-etching, with the dentinal tubule surfaces bonded with composite resin blocks in each group. After the standard test models of dentinal tubule-composite resin blocks were placed in distilled water and stored at 37℃ for 24 h, shearing tests were performed using a universal material testing machine at a crosshead speed of 0.5 mm/min. The bond strength values in the vertical group were 19.33＋1.59 MPa for the 20% phosphoric acid group, 21.39±2.34 MPa for the 35% phosphoric acid group, and 16.88±1.54 MPa for the self-etching group. The bond strength values in the parallel group were 24.53±1.99 MPa for the 20% phosphoric acid group, 25.16＋2.88 MPa for the 35% phosphoric acid group, and 20.83±1.99 for the self-etching group. After using same total-etching adhesive, the shear bond strength of the parallel group was higher than that of the vertical group, and the difference was statistically significant （P〈0.05）. Regardless of vertical group or parallel group, the difference in the bond strength value between the total-etching groups and the self-etching group was statistically significant （P〈0.05）. It was concluded that the dentin bonding substrate which was parallel to the direction of the dentin tubule achieved an improved bond strength; the total-etching adhesives achieved higher bond strengths in dentin bond than the self-etching adhesives.

Anti-proteolytic capacity and bonding durability of proanthocyanidin-biomodified demineralized dentin matrix

Our previous studies showed that biomodification of demineralized dentin collagen with proanthocyanidin（PA） for a clinically practical duration improves the mechanical properties of the dentin matrix and the immediate resin–dentin bond strength. The present study sought to evaluate the ability of PA biomodification to reduce collagenase-induced biodegradation of demineralized dentin matrix and dentin/adhesive interfaces in a clinically relevant manner. The effects of collagenolytic and gelatinolytic activity on PA-biomodified demineralized dentin matrix were analysed by hydroxyproline assay and gelatin zymography. Then, resin-/dentin-bonded specimens were prepared and challenged with bacterial collagenases. Dentin treated with 2% chlorhexidine and untreated dentin were used as a positive and negative control, respectively. Collagen biodegradation, the microtensile bond strengths of bonded specimens and the micromorphologies of the fractured interfaces were assessed. The results revealed that both collagenolytic and gelatinolytic activity on demineralized dentin were notably inhibited in the PA-biomodified groups, irrespective of PA concentration and biomodification duration. When challenged with exogenous collagenases, PA-biomodified bonded specimens exhibited significantly less biodegradation and maintained higher bond strengths than the untreated control. These results suggest that PA biomodification was effective at inhibiting proteolytic activity on demineralized dentin matrix and at stabilizing the adhesive/dentin interface against enzymatic degradation, is a new concept that has the potential to improve bonding durability.

Bonding Efficacy of a Self-adhesive Resin Cement to Enamel and Dentin

With the objective to evaluate the bonding efficacy of a new self-adhesive resin cement（RelyX Unicem, 3M ESPE） to enamel and dentin using a shear bonding strengths test with or without acid etching pretreatment, flat buccal dentin surface and mesial/distal enamel surface were made using a high-speed diamond bur. Copper rings were luted using Rely X Unicem（RU; 3M ESPE）, Panavia F（PF; Kuraray） or Vitique（VI; DMG）. For RU, the shear bonding strengths using GL（Gluma Etch, Heraeus） acid etching pretreatment were also tested. The teeth were placed into copper rings（inner diameter： 16 mm, height： 4mm） and embedded in methylmethacrylate resin. The specimens were stored for 24 h in distilled water at 37 ℃ prior to shear bonding strengths testing. In addition, bond failures were examined by optical microscope and categorized as 4 models such as different adhesive, cohesive, or mixed. Shear bonding strengths were calculated by dividing the maximum debonding force over the cross sectional area of each specimen. The Kruskal-Wallis test was used to determine pairwise statistical differences（P 〈 0.05） in SBS between the experimental groups. For dentin bonding strength, statistical analysis showed that there was no significant difference among RU（12.84 MPa）, PF（14.93 MPa） and VI（11.03 MP）; and the bonding strengths of them were higher than RU with acid etching pretreatment（9.12 MP）. When bonded to enamel, PF（17.99 MP） and VI（17.58 MP） scored significantly higher than RU efficacy.The use of self-adhesive cement Rely X Unicem can obtain the bonding strengths to dentin similar to traditional resin cements. Phosphoric acid etching can improve the bonding strengths of the selfadhesive resin cement to enamel, but was negative for dentin.

Isotropic shear bond strength behavior of superficial bovine dentin: A pilot study

The aim of this pilot study was to evaluate the shear bond strength of superficial bovine incisor dentin in different crown regions. Bonding was performed to the incisal, middle and cervical thirds of superficial bovine coronal dentin (n = 20) with a two-step etch-and-rinse adhesive (Optibond Solo Plus) and resin composite (Z100). Shear bond strength was evaluated at 24 h and failure modes of representative specimens wereobserved with FE-SEM. Non-parametric Kruskal-Wallis test with a significance level of 0.05 was used for data analysis. Mean shear bond strength values for the incisal, middle, and cervical thirds were 36.9 (3.1), 42.6 (2.6), and 37.1 (2.1) respectively with no significant differences evidenced between the crown thirds (p = 0.19). Observation of the failure mode of representative specimens demonstrated that specimens with high bond strength values exhibited predominantly mixed-type failures whereas low strength specimens exhibited adhesive failures between the dentin and adhesive. The absence of significant differences in shear bond strength between crown thirds indicate that, regardless of tubule orientation, any crown region can be used when superficial bovine incisor dentin is used for shear bond strength testing.

An in Vitro Comparison of Bonding Effectiveness of Different Adhesive Strategies on Erbium:Yttrium-Alluminum-Garnet Laser Irradiated Dentin

Background: To date there is not a material considered ideal for the lased dentin. Objective: To compare the bond strength to human lased dentin of self-etch and etch-and-rinse adhesive systems, a self-adhesive resin composite and a glass-ionomer cement. Methods: Forty human molars were sectioned to obtain a 2 mm-thick slab of mid-coronal dentin. The occlusal surface of each slab was polished by SiC paper (P600) for 10 s. Then an half part of dentin slabs was randomly selected for receiving treatment with 2.94 μm Er:YAG laser (DEKA, Smart 2940D Plus) with 10 Hz at 100 mJ, pulse duration of 230 μs with contact tip. Dentin slabs were randomly divided into four groups (n = 10). Six conical frustum-shaped build-ups were constructed on the occlusal surface of each dentin slab using bonding agents (OptiBond Solo Plus Group 1;OptiBond All-in-one Group 2) combined with a resin composite (Premise Flow), self-adhesive resin composites (Vertise Flow Group 3) and a glass-ionomer cement (Ketac-Fil Group 4). Specimens were subjected to μSBS test. Data were analyzed by a mixed model and Tukey’s test. Results: Measured bond strengths were (mean ± standard deviation): 20.8 ± 5.5 MPa (laser treatment) and 15.6 ± 4.5 MPa (SiC paper) for Group 1, 18.9 ± 5.3 MPa (laser treatment) and 14.0 ± 4.3 MPa (SiC paper) for Group 2, 7.9 ± 2.8 MPa (laser treatment) and 4.3 ± 2.2 MPa (SiC paper) for Group 3, 4.7 ± 1.9 MPa (laser treatment) and 2.6 ± 1.2 MPa (SiC paper) for Group 4. The inferential analysis showed that the dentin laser treatment significantly affected the bond strength within each individual group. On dentin treated with laser the bond strengths recorded for build-ups constructed with etch and rinse and self-etch adhesive systems were significantly higher than those recorded for build-ups constructed with self-adhesive resin composite and glass-ionomer cement (p < 0.0001). Similarly, on dentin treated with SiC paper the bond strengths recorded for build-ups constructed with etch and rinse and self-etch adhesive systems were significantly higher than those recorded for build-ups constructed with self-adhesive resin composite and glass-ionomer cement (p < 0.0001). Conclusion: Er:YAG laser treatment has increased the shear bond strength of all the adhesive materials used.

Comparison of Two Methods of Chlorhexidine Application of Shear Bond Strength Degradation between Composite Resin and Dentin

Background: Chlorhexidine could have effect on shear bond strength of composite resin-dentin. Objective: The purpose of this study is to compare two methods of chlorhexidine application of shear bond strength degradation between composite resin and dentin. Methods: Thirty samples of dentin were taken from the crown of premolars and then divided into three groups (n = 10). Group 1 were applied bonding without chlorhexidine, group 2 were applied with liquid chlorhexidine and followed by bonding, group 3 were applied bonding which contains chlorhexidine. Each group was divided into two sub-groups (n = 5): the group with and without 10% NaOCl immersion for one hour. Then, 4 samples in each sub-group were used to measure shear bond strength using Universal Testing Machine, and 1 sample was examined with Scanning Electron Microscope (SEM). Data were analyzed using SPSS 17 by Mann-Whitney and Kruskal Wallis test. Results: The highest mean shear bond strength without 10% NaOCl immersion was in group 1, while the highest mean with 10% NaOCl immersion was in group 3. Significant differences occurred between the groups 1 and 2, groups 2 and 3. Conclusion: Method of using bonding contains chlorhexidine can increase and inhibit degradation shear bond strength between composite resin and dentin.

Surface preparation and isotropic shear bond strength properties of superficial bovine dentin

The effect of different types of surface preparation with SiC abrasive paper on the shear bond strength (SBS) of superficial bovine dentin obtained from the incisal, middle and cervical thirds were evaluated. Dentin substrates were obtained with twenty specimens for each locationgrit combination. Superficial dentin was exposed and prepared to 120-, 320-, or 600-grit SiC;the dentin surfaces were treated with Optibond Solo Plus (Kerr) and polymerized for 20 s. The specimens were placed in a jig, filled with resin composite Z100 (3M-ESPE), polymerized for 40 s according to manufacturer’s instructions, and stored for 24 h at 37℃ and 100% humidity. After 24 h, SBS was measured using a loading testing machine (Ul-tradent) and expressed in megapascals. A two-way ANOVA and Tukey test were used for data analysis. No statistically significant effect of the location (P = 0.254) or interaction grit-location (P = 0.629) were observed on SBS. Statistically significant effect of the grit on the SBS was detected (P < 0.001) with 320-grit being statistically different from 600-grit (P = 0.011) and 120-grit (P < 0.001). No significant differences were observed between 600-grit and 120-grit (P = 0.413). Regardless of the location, 320-grit consistently showed the lowest SBS indicating that different surface grit preparations have an effect on dentin SBS values.

Immediate and delayed micro-tensile bond strength of different luting resin cements to different regional dentin

We sought to evaluate immediate and delayed micro-tensile bond strength of Panavia F2.0 and Multilink Sprint resin cement to superficial, deep and cervical dentin. Thirty-six freshly extracted non-carious human molars were sectioned in the mesiodistal direction to expose three different dentin regions including superficial dentin （1 mm below the dentine-enamel junction）, deep dentin （1 mm above the highest pulp horn） and cervical dentin （0.5 mm above the cemento-enamel junction and 0.5 mm below the dentine-enamel junction）. Resin cements were applied on dentin surfaces and composite blocks were luted under constant seating pressure. Each group was divided into three subgroups according to time intervals. Specimens were sectioned to obtain sticks of 1 mm2 in diameter and subjected to microtensile bond strength testing at a cross head speed of 1 mrn/min. Both resin cements showed higher micro-tensile bond strength to superficial dentin than that to deep or cervical dentin （P 〈 0.001）. Micro-ten- sile bond strengths of Panavia F2.0 were higher than those of Multilink Sprint at different dentin regions （P 〈 0.001）. Immediate ＂micro-tensile bond strengths were higher than those of delayed micro-tensile bond strengths for both resin cements （P 〈 0.001）. It was concluded that resin cements with different chemical formulations and applications yield significantly different micro-tensile bond strengths to different dentin regions.

Influence of Phosphoric Acid Etching on the Bond Strength of a Universal Adhesive System to Caries-Affected Dentin

The purpose of this study was to evaluate the influence of acid etching on the bond strength of a universal adhesive system (Single Bond Universal, 3M) to caries-affected dentin. Forty permanent third molars were selected and carious lesions were induced by the microbiological method with?S. mutans?ATCC25175. Teeth were allocated randomly across four experimental designs (n?=?10): PA-I: phosphoric acid etching and application of the adhesive system, followed by immediate microtensile bond strength testing;PA-CC: phosphoric acid etching and application of the adhesive system, followed by microtensile bond strength testing after a 14-day cariogenic challenge;NPA-I: application of the adhesive system without acid etching, followed by immediate bond strength testing and NPA-CC: application of the adhesive system without acid etching followed by bond strength testing after 14-day cariogenic challenge. For microtensile bond strength testing,?a restoration with Charisma composite resin was made and each specimen was sectioned with a cross-sectional area of 1 mm2. Only adhesive and mixed fractures were considered for bond strength calculation. Results were evaluated by the Kruskal-Wallis and Friedman tests. The highest bond strengths were observed in the phosphoric acid etching groups (p??0.05). Cariogenic challenge did not affect bond strength (p?>?0.05). The predominant fracture type was adhesive. We conclude that phosphoric acid increased the bond strength of the Single Bond Universal system to caries-affected dentin, and that cariogenic challenge did not interfere with this bond strength.

Push-out Bond Strength of Self-adhesive Methacrylate Resin-based Sealers to Root Dentin

This study examined the adhesive strength of two self-adhesive methacrylate resin-based sealers（MetaSEAL and RealSeal SE） to root dentin and compared them with RealSeal and AH Plus in properties. A total of 48 extracted human single-rooted teeth were used to prepare the 0.9-mm thick longitudinal tooth slice（each per tooth）. Standardized simulated canal spaces of uniform dimensions were prepared in the middle of radicular dentin. After treated with 5.25% sodium hypochlorite（NaOCl） and 17% EDTA, tooth slices were allocated randomly to four groups（n=12） in terms of different sealers used： MetaSEAL, RealSeal SE, RealSeal, and AH plus groups. The simulated canal spaces were obturated with different sealers in each group. There were 10 slabs with 20 simulated canal spaces（n=20） used in each group for push-out testing. The failure modes and the ultrastructures of fractured sealer-dentin interfaces were examined. The remaining 2 slabs in each group underwent partial demineralization for observation of the ultrastructure of resin tags. The results showed that the push-out bond strength was 12.01±4.66 MPa in MetaSEAL group, significantly higher than that in the other three groups（P0.05）. Moreover, no statistically significant differences were noted in the push-out bond strength between RealSeal SE（5.43±3.68 MPa） and AH Plus（7.34±2.83 MPa） groups and between RealSeal SE and RealSeal（2.93±1.76 MPa） groups（P0.05）. Mixed failures were predominant in the fractured sealer-dentin interfaces in MetaSEAL and AH Plus groups, while adhesive failures were frequently seen in RealSeal SE and RealSeal groups. In conclusion, after complete removal of the smear layer, MetaSEAL showed superior bond ability to root dentin. The RealSeal SE is applicable in clinical practice, with its adhesive strength similar to that of AH Plus. The self-adhesive methacrylate resin-based sealer holds promise for use in endodontic treatment.

Er:YAG激光和传统车针去龋后牙本质粘接强度的比较

目的:比较使用不同模式Er:YAG激光以及传统车针去龋后牙本质与复合树脂的粘接强度。方法:选用人类离体磨牙模拟龋坏,分别采用Er:YAG激光中短脉冲(medium short pulse,MSP)模式、Er:YAG激光超短脉冲(super short pulse,SSP)模式和传统车针去除模拟的龋坏后,采用自酸蚀粘接剂将牙体标本与复合树脂粘接制成试件。使用万能试验机对试件进行拉伸试验,测得断裂负荷和粘接强度,并采用单因素方差分析和Tukey多重比较进行统计学分析。采用扫描电子显微镜观察3种不同去龋方式处理后的牙本质表面形态,以及涂布自酸蚀粘接剂并固化后试件的横截面形态。结果:使用Er:YAG激光MSP模式处理后牙本质与复合树脂的粘接强度最高,SSP模式处理后次之,传统车针处理后最低,但差异无统计学意义(P>0.05)。扫描电子显微镜图像显示,Er:YAG激光MSP模式处理后的牙本质表面较平坦,牙本质小管内几乎没有残屑;Er:YAG激光SSP模式处理后的牙本质表面呈现鳞片状,牙本质小管内可见少量碎屑;而传统车针处理后牙本质小管大部分处于被表面牙本质部分甚至完全遮盖的状态,牙本质小管内充满残屑。结论:使用Er:YAG激光去龋相比传统车针去龋可以获得较好的牙本质粘接强度,且对牙本质小管的处理深度和洁净度明显优于传统车针去龋,其中MSP模式更佳。

促牙本质再矿化树脂粘接材料提高牙本质粘接耐久性的研究进展

促进牙本质再矿化是提高树脂-牙本质粘接耐久性的重要方法,国内国际有很多关于改性树脂粘接剂的研究,均致力于诱导混合层裸露牙本质胶原的再矿化。本文针对树脂-牙本质粘接面的耐久性问题,阐述了促牙本质再矿化树脂粘接材料的研究进展。促牙本质再矿化树脂粘接材料的改性策略包括:生物活性无机微填料策略,即以硅酸盐、磷酸钙盐和生物活性玻璃等无机材料为矿化离子来源诱导牙本质再矿化;仿生再矿化策略,即应用仿生类似物模拟非胶原蛋白(non-collagenous proteins,NCPs)的功能,引导矿物前驱体在特定位点矿化以获得与生物矿化类似的有序晶体沉积;以及锌添加剂保护胶原蛋白、介孔硅材料作为矿物离子输送系统的改性策略。

Single Bond Universal牙本质粘结强度及牙本质保护作用的实验研究

目的:探讨通用型粘结剂(Single Bond Universal,SBU)对牙本质的粘结强度。方法:选取A组(SBU)、B组(S3bond)和C组(hybrid coat,Hy C)三组不同类型处理剂,分别比较A组与B、C两组的牙本质微拉伸粘结强度。各组样本数量相同(n=30),结果通过两独立样本t检验进行统计学分析(α=0.05),通过扫描电镜观察断裂模式。结果:A组拉伸强度约23.371MP,与B组间无统计学差异,显示了与B组同等的粘结强度;与C组(17.314MP)比较,A组显示了较高的粘结强度,两组间有显著的统计学差异。断裂模式显示,三组断裂都主要以界面断裂为主,A、B两组样本断面可见牙本质小管结构,C组可见极少量牙本质小管结构。结论:通用型粘结剂Single Bond Universal具备与传统自酸一步法粘结剂同等的粘结强度,可以满足临床粘结要求;Single Bond Universal作为牙本质保护膜用于即刻牙本质封闭时,对牙本质小管有一定的封闭作用,并且可以获得较hybrid coat牙本质保护膜更高的粘结力,但其对牙本质小管的封闭效果还有待进一步实验研究。

Primer containing dimethylaminododecyl methacrylate kills bacteria impregnated in human dentin blocks

Antibacterial dimethylaminododecyl methacrylate （DMADDM） was recently synthesized. The objectives of this study were to： （1） investigate antibacterial activity of DMADDM-containing primer on Streptococcus mutans impregnated into dentin blocks for the first time, and （2） compare the antibacterial efficacy of DMADDM with a previous quaternary ammonium dimethacrylate （QADM）. Scotchbond Multi-Purpose （SBMP） bonding agent was used. DMADDM and QADM were mixed into SBMP primer. Six primers were tested： SBMP control primer P, P＋2.5% DMADDM, P＋5% DMADDM, P＋7.5% DMADDM, P＋10% DMADDM, and P＋10% QADM. S. mutans were impregnated into human dentin blocks, and each primer was applied to dentin to test its ability to kill bacteria in dentinal tubules. Bacteria in dentin were collected via a sonication method, and the colony-forming units （CFU） and inhibition zones were measured. The bacterial inhibition zone of P＋10% DMADDM was 10 times that of control primer （P〈0.05）. CFU in dentin with P＋10% DMADDM was reduced by three orders of magnitude, compared with control. DMADDM had a much stronger antibacterial effect than QADM, and antibacterial efficacy increased with increasing DMADDM concentration. Dentin shear bond strengths were similar among all groups （P〉0.1）. In conclusion, antibacterial DMADDM-containing primer was validated to kill bacteria inside dentin blocks, possessing a much stronger antibacterial potency than the previous QADM. DMADDM-containing bonding agent was effective in eradicating bacteria in dentin, and its efficacy was directly proportional to DMADDM mass fraction. Therefore, DMADDM may be promisine for use in bonding agents as well as in other restorative and oreventive materials to inhibit bacteria.

黏结剂Single bond 2不同涂布方式下人牙本质黏结界面的环境扫描电镜观察

目的:比较黏结剂S ingle bond 2不同涂布方式下牙本质黏结界面的形态学变化,为临床选择黏结剂应用方法提供参考依据。方法:暴露新鲜拔除的人第三磨牙牙本质,应用不同方式(包括涂布力度、方向、层数和固化次数)分组进行黏结剂涂布,然后,在环境扫描电镜下直接观察牙本质黏结界面的形态差异。根据黏结剂分布是否均匀、封闭牙本质小管的程度以及黏结剂渗入牙本质小管的情况判断效果。结果:黏结剂涂布力度方面,轻涂比重涂好;涂布方向,同向涂布比反复涂布好;涂布层数,涂2层较涂1层或4层好;固化方式,固化1次较固化2次好。结论:临床使用第五代黏结剂S ingle bond 2时,推荐同向轻涂2遍后固化的方法,可使黏结剂均匀分布,并较好地封闭牙本质小管。

铒激光预处理对牙本质、牙釉质粘结强度及CAD/CAM玻璃陶瓷嵌体修复牙体缺损边缘微渗漏的影响

目的:探讨铒激光预处理对牙本质、牙釉质粘结强度及CAD/CAM玻璃陶瓷嵌体修复牙体缺损边缘微渗漏的影响。方法:收集2020年1月—2023年1月口腔外科门诊拔除的新鲜、无龋坏变色、无隐裂智齿62颗,根据预处理方式不同,随机分为铒激光组和磷酸组,每组31颗,每组再随机分为2份,分别用于粘结强度测试(16颗)和微渗漏测试(15颗)。比较2组牙釉质、牙本质抗剪切粘结强度和微渗漏程度及微渗漏评分分布情况。采用SPSS 17.0软件包对数据进行统计学分析。结果:铒激光组牙釉质、牙本质抗剪切粘结强度显著高于磷酸组(P<0.05);铒激光组侧壁、龈壁微渗漏程度显著低于磷酸组(P<0.05),铒激光组侧壁微渗漏评分主要为1分和2分,磷酸组侧壁微渗漏评分主要为2分,2组侧壁微渗漏评分分布相比,差异有统计学意义(P<0.05);铒激光组龈壁微渗漏评分主要为1分和2分,磷酸组龈壁微渗漏评分主要为2分和3分,2组龈壁微渗漏评分分布相比,差异有统计学意义(P<0.05)。结论:铒激光预处理可提高瓷嵌体与牙本质、牙釉质粘结强度,同时还可减少CAD/CAM玻璃陶瓷嵌体微渗漏,增强嵌体边缘密合性。

Super-Bond C&B治疗后牙咬合面牙本质过敏的疗效分析

目的观察Super-Bond C&B治疗后牙咬合面牙本质过敏症的治疗效果。方法收集因后牙咬合面牙本质过敏就诊的患者106例,共184颗患牙,随机分为两组,治疗组53例96颗患牙,用Super-Bond C&B脱敏治疗;对照组53例88颗患牙,用75%氟化钠甘油糊剂脱敏治疗。在同一标准下进行即刻和3个月后的疗效对照分析。结果 Super-Bond C&B和75%氟化钠甘油糊剂治疗的即刻有效率分别为97.91%和92.04%,两组无显著性差异(P>0.05);3个月后观察有效率分别为89.58%、38.64%,两组间差异具有统计学意义(P<0.05)。结论 Super-Bond C&B对后牙咬合面牙本质过敏症具有较好的治疗效果,可以推广应用。

脱敏剂对活髓牙全瓷修复影响的相关实验研究

目的研究不同类型脱敏剂对活髓牙牙本质小管封闭以及全瓷修复黏接效果的影响,为临床上活髓牙全瓷修复选用脱敏剂提供依据。方法收集健康完好离体第三磨牙12颗,牙体预备后制备牙本质片,将牙冠分为两半,共分出牙体24块,随机分为4组,每组6块:对照组(仅清洁牙本质表面并吹干)、双氟-12组(涂布氟化物脱敏剂:双氟-12脱敏剂)、奥敏清组(涂布生物活性玻璃为主要成分的脱敏剂:奥敏清脱敏剂)、Gluma组(涂布HEMA-戊二醛类脱敏剂:Gluma脱敏剂)。SEM电镜扫描不同实验组表面特征,计算牙本质小管封闭率。在各组实验件表面按规范程序黏接瓷块后,万能力学测试仪检测最大剪切力,分析实验结果。结果电镜扫描结果显示,Gluma组界面光滑平整,沉积物少,视野内仅有少数牙本质小管口可见。奥敏清组的牙本质小管封闭率(33.6%)显著高于对照组(10.7%),显著小于Gluma组(82.1%)和双氟-12组(80.0%),差异有统计学意义(P<0.05)。与对照组比较,Gluma组显著增强了最大剪切力(P<0.05),奥敏清组和双氟-12组最大剪切力显著下降(P<0.05)。结论含有HEMA-戊二醛类脱敏剂是一种合适的全瓷冠修复活髓隐裂牙的脱敏剂,而氟化物和生物活性玻璃类脱敏剂均不建议用于全瓷冠修复活髓隐裂牙的脱敏。

All—Bond Ⅱ牙本质粘合剂在牙体修复中的应用

作者自1995年5月至9月应用All—Bond Ⅱ粘合剂和复合树脂行牙体修复121例。经一年临床观察All—Bond Ⅱ有较强的粘接力,具有亲水性、能在潮湿的牙面上粘合、符合生理要求,对牙髓刺激较少,但在近髓的窝洞仍需垫底。也可以作为牙本质过敏的脱敏剂。

诺丽对冠部牙本质粘接强度及纳米渗漏的影响

目的探讨诺丽(Morinda citrifolia juice,MCJ)联合乙二胺四乙酸盐(ethylene diaminete traacetic acid,EDTA)根管冲洗对冠部牙本质粘接强度及纳米渗漏的影响,并与临床上最常用的根管冲洗液次氯酸钠(sodi⁃um hypochlorite,NaClO)相比较,为临床应用提供参考。方法本研究已通过单位伦理审查委员会批准。选取63颗因正畸拔除的人前磨牙,去除表面釉质暴露牙本质平面后,根据冲洗液不同随机分为对照组(蒸馏水组)和6个实验组,即:A组2.5%NaClO、B组5.25%NaClO、C组6%MCJ、D组2.5%NaClO⁃17%EDTA、E组5.25%NaClO⁃17%EDTA和F组6%MCJ⁃17%EDTA(n=9),分别用相应冲洗液浸泡20 min后,在其表面分层堆积4 mm×4 mm×3 mm的Z350树脂块,每组选取6个样本,低速切割机将每个样本切割成1 mm×1 mm×8 mm的试件条,进行微拉伸粘接强度测试,随后在体视显微镜下观察断裂类型;每组剩余的3个样本经老化后切割成1 mm厚的薄片,进行界面纳米渗漏测试以及扫描电子显微镜下观察树脂⁃牙本质粘接界面。结果各组微拉伸粘接强度测试值均有显著性差异(P<0.05),对照组粘接强度最高。实验组中,B组粘接强度最低,以粘接界面破坏为主;F组粘接强度最高,以混合破坏为主。各组纳米渗漏值均有显著性差异(P<0.05),对照组纳米渗漏值最低。实验组中,B组纳米渗漏值最高、树脂突较细,F组纳米渗漏值最低、树脂突粗大且密集。结论NaClO浓度越高,冠部牙本质的粘接强度及边缘封闭性越差;MCJ联合EDTA根管冲洗对冠部牙本质的粘接强度和边缘封闭性的影响小于NaClO联合EDTA根管冲洗。