仿生矿化纳米磷酸钙对牙本质小管封闭性能的评价

目的 制备仿生矿化的纳米磷酸钙,并探讨其对牙本质小管的封闭性能。方法 采用DMEM仿生矿化策略制备无定形磷酸钙材料(DMEM based amorphous calcium phosphate,DACP),运用透射电子显微镜(TEM)、傅里叶变换红外光谱扫描(FTIR)等检测观察其理化表征。选择口腔上皮角质形成细胞(HOK)和牙髓细胞(DPC)分别与材料共培养24 h后,CCK-8法评估材料的生物相容性。收集完整无龋的牙齿制备牙本质片,用DACP材料悬液均匀涂抹牙本质片,设置阳性对照NovaMin组和空白对照组,分别处理1、7 d后扫描电子显微镜(SEM)评估牙本质片的表面和截面封闭效果。结果 TEM显示DACP为均匀球形无定形纳米颗粒,随矿化时间的延长粒径有所增加。CCK-8结果显示HOK和DPC在25、50、100、200 μg/mL DACP下细胞活力均较好,提示材料有较好的生物相容性。牙本质片被处理1 d后DACP组牙本质小管大部分封闭;被处理7 d后DACP组牙本质小管表面呈现完全封闭的状态,且牙本质片截面可见DACP可渗入小管内。结论 运用DMEM仿生矿化策略制备的纳米磷酸钙具有较好的生物相容性和牙本质小管封闭作用,有望成为一种新的脱敏材料。     

聚酰胺-胺型树枝状分子对牙本质小管的封闭作用

目的 研究聚酰胺-胺型树枝状分子(polyamidoamine dendrimer,PAMAM)封闭牙本质小管的效果,为牙本质敏感的治疗提供实验依据.方法 选取7颗健康第三磨牙制备28个牙本质薄片,按随机数字表分为A、B、C、D、E、F、G7组,G组为空白对照组不作处理,A～E组经脱矿后置于含PAMAM的0.25％戊二醛水溶液中4℃24h,然后A～E组分别在再矿化液中矿化0、6、12、18和24h,F组脱矿后直接于再矿化液中矿化24h.用场发射扫描电子显微镜(field emission scanning electron microscope,FE-SEM)、X射线衍射(X-ray diffraction,XRD)和能量色散X射线分光计(energy dispersive X-ray spectrometer,EDXS)观察检测.结果 FE-SEM可见各组牙本质样本矿化程度不同,随矿化时间延长,样本表面矿化物逐渐形成,直至完全覆盖样本表面,矿化物可封闭牙本质小管达一定深度.矿化物经EDS和XRD检测证实为羟基磷灰石晶体.结论 PAMAM具有良好的牙本质小管封闭作用,在牙本质敏感的治疗方面有一定的潜在应用价值.     

不同粒径和形貌的羟基磷灰石对牙本质小管的堵塞作用及耐磨性研究

目的 从定性和定量两方面研究不同粒径和形貌的羟基磷灰石(Hydroxyapatite,HA)对牙本质小管的堵塞作用及其耐磨性.方法 选择人前磨牙40颗,以高速手机制取牙本质片并抛光,酸蚀后随机均分为4组:20 nm HA组;30 nm HA组;12μm HA组;空白对照组(不使用任何实验品).各组分别用对应的材料刷洗牙本质片表面7d.将牙本质片一分为二,一半扫描电镜观察;另一半进行刷牙磨耗实验后扫描电镜观察,应用Image-Pro Plus 6.0图像分析软件计算牙体质小管堵塞率.结果 扫描电镜下见牙本质小管被颗粒状物堵塞,堵塞率达82%~96%,平均堵塞率为30 nm HA组(短棒状)>20 nm HA组(针状)>12μm HA组(球形).牙刷磨耗实验后,扫描电镜下见牙本质表面沉积层光滑致密,仍有63%以上的小管被封闭.结论 30 nm短棒状HA、20 nm针状HA及12μm球形HA对牙本质小管均具有良好的堵塞作用及耐磨性.     

酪蛋白磷酸多肽钙磷复合体的应用顺序对乳牙牙本质粘结强度的影响

目的探讨酪蛋白磷酸多肽钙磷复合体(casein phosphopetide-amorphic calcium phosphat, CPP-ACP)应用顺序对乳牙牙本质粘结强度及对乳牙牙本质小管封闭作用的影响。方法选取人56颗无龋乳磨牙,磨除牙合面釉质,制备牙本质平面。将其中48颗乳磨牙随机分3大组(n=16)。A组:仅酸蚀15 s。B组:涂CPP-ACP后酸蚀15 s。C组:酸蚀15 s后涂CPP-ACP。各组分为2小组(n=8),其中AN,BN,CN组使用Prime&Bond NT(NT)全酸蚀粘结剂,AS,BS,CS组使用Single bond 2(SB2)全酸蚀粘结剂。制作树脂粘结试件,电子万能试验机测定剪切强度(SBS值)。其余8个乳磨牙随机分成4组(n=2),分别为空白组(S1组)、酸蚀组(S2组)、酸蚀后涂CPP-ACP组(S3组)、涂CPP-ACP后酸蚀组(S4组)分别用扫描电镜观察粘结前牙本质小管封闭情况。结果剪切实验结果为AN组、BN组、CN组剪切强度无统计学差异(P>0.05);AS组,BS组,CS组剪切强度也无统计学差异(P>0.05);AN组>AS组,BN组>BS组,CN组>CS组差异有统计学意义(P<0.05)。扫描电镜结果为S3组中牙本质小管封闭数目最多。结论在酸蚀后应用CPP-ACP处理乳牙牙本质不影响NT和SB2两种全酸蚀粘结剂的粘结强度;可以达到有效的牙本质小管封闭;Prime&Bond NT(NT)全酸蚀粘结系统的粘结强度高于Single bond 2(SB2)。     

CPP-ACP/ACFP预处理的牙本质与树脂粘结剂粘结作用的研究

目的:通过设立对比实验,研究酪蛋白磷酸肽-无定形磷酸钙(Casein phosphopetide-amorphic calcium phosphat,CPP-ACP)及酪蛋白磷酸肽-无定形磷酸氟钙(Casein phosphoetide-amorphic calcium fluoride phosphate complexes,CPP-ACFP)对牙本质小管的封闭效果及对树脂粘结剂粘结强度的影响。方法:将36个试件随机分为自酸蚀和全酸蚀组,每组再分空白组、GC组、GC plus组3个亚组(n=6)。采用扫描电子显微镜(SEM)观察CPP-ACP和CPP-ACFP预处理牙本质1 d和7 d后的表面形貌改变;用能谱分析,计算钙磷比值,分析羟基磷灰石晶体结构和成份;每个试件上均堆积厚约4 mm的Z350树脂,通过万能测试机进行微拉伸强度测试,分析CPP-ACP和CPP-ACFP预处理对粘结剂粘结强度的影响;使用体视显微镜,观察界面的断裂模式,并对结果进行统计分析。结果:SEM显示,经预处理的牙本质小管直径减小,经多次预处理与1次相比,牙本质小管几乎完全封闭;能谱分析表明经预处理的牙本质与空白组牙本质Ca∶P比值变化并无统计学差异,新形成的羟基磷灰石结构和成份与牙本质类似;微拉伸实验结果显示,在牙本质表面应用CPP-ACP或CPP-ACFP后,可降低全酸蚀粘结剂single bond2的粘结强度(P＜0.05),而对自酸蚀粘结剂ibond的粘结强度无明显影响;两者对同一种粘结剂粘结强度的影响无统计学意义;体视显微镜观察,各组断裂模式均以粘结面断裂为主。结论:粘结前使用CPP-ACP或CPP-ACFP预处理牙本质表面,可以封闭牙本质小管,多次应用效果更加显著;CPP-ACP或CPP-ACFP预处理后对自酸蚀粘结剂粘结强度没有影响;会降低全酸蚀粘结剂的粘结强度。     

三种新型钙盐脱敏剂封闭牙本质小管的体外研究

目的 体外比较3种新型钙盐脱敏剂封闭牙本质小管的效果,以期为临床应用提供参考.方法 新鲜离体第三磨牙25颗,制备成1.00 mm厚的牙本质薄片,6%柠檬酸处理后,按随机数字表法分为5组(n=5),分别用蒸馏水(A组)、NovaMin(B组)、Pro-Argin(C组)、酪蛋白磷酸肽-无定形非晶体磷酸钙(D组)、75%NaF甘油(E组)处理样本冠面2 min,纵向劈开,扫描电镜观察牙本质表面和剖面后,测量牙本质小管封闭数目比及封闭深度,X射线能谱分析表面元素组成和剖面钙磷元素变化趋势.结果 A组牙本质小管完全开放,B、C、D、E组牙本质小管封闭数目比分别为(81.6±6.1)%、(71.5±6.3)%、(43.2±2.6)%、(39.9±4.1)%;剖面封闭深度分别为(30.33±2.26)、(24.55±2.58)、(16.10±4.65)、(8.90±1.51)μm;表面封闭数目比和剖面封闭深度4组间差异有统计学意义(P＜0.01),但B、C组间差异无统计学意义(P＞0.05);5组钙磷比差异无统计学意义(P=0.342).结论 体外牙本质小管即刻封闭效果比较,NovaMin处理组在牙本质表面和剖面均显示出较好的封闭性能,可形成类牙本质样物质.

Abstract：

Objective To evaluate the occluding effects of three new calcium desensitizers on dentinal tubules in vitro. Methods Twenty-five dentin specimens of 1.00 mm thick from freshly extracted third molars were divided into five groups randomly. After treatment with 6% citric acid, group A was treated with distilled water, and group B-E were treated with NovaMin, Pro-Argin, casein phosphopeptide-amorphous calcium phosphate( CPP-ACP), and 75% NaF glycerin for 2 min respectively. Then the teeth were vertically cleaved into two sections. The surfaces and cross sections were observed by the scanning electron microscope(SEM) and energy dispersive X-ray (EDX), which were analyzed by the Image-Pro Plus software. Results The percentage of dentin tubules sealed were ( 81.6 ± 6. 1 ) %, ( 71.5 ± 6. 3 ) %, (43.2 ± 2. 6) %, ( 39. 9 ± 4. 1 ) %for groups B, C, D and E respectively, and the occluding depth were ( 30. 33 ± 2. 26 ), ( 24. 55 ± 2. 58 ),(16. 10 ±4. 65) and (8. 90 ± 1.51 ) μm respectively. The differences between these groups were statistically significant (P＜0. 01) except for group B and C (P ＞0.05). However, there was no significant difference between all the groups for the Ca/P ratios ( P = 0. 342). Conclusions NovaMin may have better immediate occluding effects than other desensitizers and could deposit a dentin-like mineral.     

两种不同方法使用生物活性玻璃治疗牙本质敏感的体外试验研究

目的:体外比较涂抹法和透明压膜托盘法使用生物活性玻璃脱敏剂在短时间内对牙本质小管的封闭效果。方法:制取56颗离体牙的牙本质片,6%柠檬酸脱矿后按处理方法和处理时间不同随机分为7组,涂抹法1 d、3 d、7 d组(A1、A2、A3),压膜法1、3、7 d组(B1、B2、B3),空白对照组(C)。通过场发射扫描电镜(FESEM)观察比较各组牙本质小管封闭效果及再矿化物深度,X射线能谱分析(EDX)两种方法处理后牙本质表面再矿化物成分。结果:FESEM显示涂抹法和透明压膜托盘法使用生物活性玻璃脱敏剂后均能很好的封闭牙本质小管,牙本质小管内均可见明显矿化物沉积,牙本质小管暴露率A1组和B1组间无显著差异,A2组>B2组,A3组>B3组,差异有统计学意义(P<0.05);空白对照组牙本质小管口开放,周界清晰,牙本质小管暴露率为(19.11±1.27)%。纵剖面观察AB组小管内均有再矿化沉积物。X射线能谱分析(EDX)分析,各组间牙本质表面钙/磷比无显著性差异。结论:透明压膜托盘法在短时间内可以显著提高生物活性玻璃对敏感牙本质小管的封闭效果,与涂抹法相比,封闭效果有显著性提高。     

羟磷灰石牙本质脱敏剂对温和型通用型粘接系统粘接性能研究

目的 本研究旨在评估含羟磷灰石（HA）脱敏剂封闭牙本质小管的效果及其对温和型通用型粘接剂粘接性能的影响。 方法 收集完整的第三磨牙,制备冠中部牙本质样本,建立牙本质敏感模型。根据不同的脱敏处理方式随机分为4组,分别进行下述处理：无脱敏处理（对照组）、Biorepair牙膏处理（含HA脱敏牙膏）、Dontodent牙膏处理（含HA脱敏牙膏）和HA糊剂处理。通过扫描电镜（SEM）观察牙本质小管封闭情况,并评估牙本质小管封闭率。分别使用All-Bond Universal、Single Bond Universal和Clearfil Universal Bond以自酸蚀模式应用于脱敏处理后的牙本质。通过接触角测量评估脱敏处理后牙本质表面的润湿性和表面能（SFE）。制备树脂-牙本质粘接试样,测试微拉伸粘接强度,分析脱敏处理方式对于3种通用型粘接剂的牙本质微拉伸粘接强度的影响。 结果 SEM显示含HA脱敏牙膏和HA脱敏剂处理后牙本质小管均明显封闭,封闭率HA组>Biorepair组>Dontodent组（P<0.05）。接触角分析表明,含HA脱敏剂对通用型粘接剂的润湿性无显著影响（P>0.05）,但脱敏处理后牙本质SFE显著增加（P<0.05）。微拉伸粘接强度测试表明,含HA脱敏牙膏会降低微拉伸粘接强度（P<0.05）,而HA组与对照组的微拉伸粘接强度之间差异无统计学意义（P>0.05）。 结论 含HA脱敏牙膏能够形成牙本质小管封闭。在使用温和型通用型粘接剂进行后续树脂修复时,含HA脱敏牙膏降低牙本质粘接强度,而HA糊剂的脱敏处理未对粘接性能产生不利影响。     

激光促进氟保护漆对牙本质小管的封闭作用

目的 探讨Nd:YAG激光与氟保护漆联合应用对牙本质小管的封闭作用。方法 将24个牙本质块随机分为A、B、C、D4组,均用37%H3PO4处理表面。A组作为对照。B、C、D组均涂以一薄层氟保护漆,然后D组标本经Nd:YAG激光照射。以正常刷牙力度同时刷C、D2组牙本质块10min。所有标本以扫描电镜（scanning electron microscope,SEM）观察并照相。结果 A组显示大量牙本质小管口开放,管口直径约2～3um。B组显示牙本质表面被氟保护漆均匀覆盖。C组显示氟保护漆大部分被刷去。D组显示仍有超过80%的牙本质小管口被氟保护漆所封闭。结论 在同样的刷牙条件下,将Nd:YAG激光与氟保护漆联合应用,仍有大部分牙本质小管口被封闭。     

Seal ＆ Protect封闭剂治疗牙本质过敏症的疗效评价

目的 观察Seal＆Protect封闭剂治疗牙本质过敏症的作用,通过扫描电镜观察Seal＆Protect封闭人离体牙牙本质小管的效果。方法 牙本质过敏患牙180颗,实验组90颗,用Seal＆Protect治疗,对照组90颗用30％草酸钾治疗。取离体牙30颗,于颈部制备洞型,分3组(第1组涂布Seal＆Protect,第2组涂布30％草酸钾,第3组未经任何处理作空白对照)扫描电镜观察表面形态。结果 实验组治疗后的即刻疼痛缓解有效率100％,3个月复查有效率97.78％,而用30％草酸钾即刻疼痛缓解有效率为96.67％,3个月复查有效率87.78％,两者有显著差异(P<0.05)。SEM观察显示经Seal＆Protect和草酸钾处理,大部分牙本质小管被封闭。结论 Seal＆Protect能有效地封闭牙本质小管,是一种有效的治疗牙本质过敏症的脱敏剂。     

Effect of endodontic irrigation on bonding of resin cement to radicular dentin

The influence of endodontic irrigation on shear bond strengths of resin cement to radicular dentin was investigated. Human radicular dentin blocks were divided into four groups and subjected to one of four endodontic irrigations: ethylenediaminetetraacetic acid (EDTA) group, 17% EDTA for 60 s; EDTA/sodium hypochlorite (NaOCl) group, 17% EDTA for 60 s followed by 10 ml of 5% NaOCl for 15 s; NaOCl group, 10 ml of 5% NaOCl for 15 s; and control group, no treatment. Morphological changes of dentin surface after endodontic irrigation were observed by scanning electron microscopy (SEM). A resin block was bonded to the radicular dentin after irrigation using resin cement with either wet-bonding (Uni-Etch/One-Step; Bisco) or self-etching (Tyrian SPE/One-Step Plus; Bisco) adhesives. Shear bond strengths were measured and the penetration of resin tags into dentinal tubules at resin-dentin interface was observed by SEM. With the wet-bonding system, the shear bond strengths for the EDTA/NaOCl group, in which dentinal tubules openings and uniform resin tag penetration into dentinal tubules were observed, were significantly higher than the EDTA and control groups. With the self-etching system, the shear bond strengths were significantly lower in the EDTA group compared with the NaOCl and control groups. The effects of endodontic irrigation on the bonding of resin cement to radicular dentin depended on the dentin bonding system used.     

Evaluation of residual dentin after conventional and chemomechanical caries removal using SEM

The purpose of this in vitro study was to analyze the residual dentinal surfaces following caries removal using rotatory instruments and two chemomechanical methods (Papacárie and Carisolv), by scanning electron microscopy (SEM). Thirty primary incisors were divided into three groups, according to the caries removal method used, and their residual dentin was examined under SEM (15). After caries removal, 15 of these teeth were restored with Single Bond (3M) adhesive system and Z100 Filtek composite resin (3M). The tags of the replicas were observed under SEM. The chemomechanical caries removal methods (Papacárie and Carisolv) formed an amorphous layer, similar to the smear layer and few exposed dentinal tubules; the conventional caries removal method produced a smooth and regular dentinal surface, with typical smear layer and exposed dentinal tubules. All groups showed abundant tag formation. Scanning electron microscopy analysis revealed a difference between dentin treated with rotatory instruments and that treated with chemomechanical methods in spite of the occurrence of a similar tag formation in both groups.     

A novel bioactive glass-ceramic for treating dentin hypersensitivity

Dentin hypersensitivity (DH) is a painful response to stimulus applied to the open dentinal tubules of a vital tooth. It's a common oral condition, however, without an ideal treatment available yet. This work evaluated in vitro the effect of micron-sized particles from a novel bioactive glass-ceramic (Biosilicate) in occluding open dentinal tubules. A dentin disc model was employed to observe comparatively, using scanning electron microscopy (SEM), dentinal tubule occlusion by different products and deposition of hydroxyl carbonate apatite (HCA) on dentin surface by Biosilicate, after a single application: G1 - Dentifrice with potassium nitrate and fluoride; G2 - Two-step calcium phosphate precipitation treatment; G3 - Water-free gel containing Biosilicate particles (1%); G4 - Biosilicate particles mixed with distilled water in a 1:10 ratio; all of them after 1, 12 and 24 hours of immersion in artificial saliva. Fourier transform infrared spectroscopy (FTIR) was performed to detect HCA formation on dentin discs filled with Biosilicate after 2 minutes, 30 minutes and 12 hours of immersion in artificial saliva. SEM showed a layer of HCA formed on dentin surface after 24 hours by G4. G1, G2 and G3 promoted not total occlusion of open dentinal tubules after 24 hours. FTIR showed HCA precipitation on the dentin surface induced by Biosilicate after 30 minutes. The micron-sized particles from the bioactive glass-ceramic thus were able to induce HCA deposition in open dentinal tubules in vitro. This finding suggests that Biosilicate may provide a new option for treating DH.     

Scanning electron microscopic characterization of sensitive vs. insensitive human radicular dentin

Our aim was to investigate the structural changes of dentinal tubules in specimens obtained from both hypersensitive and naturally desensitized areas in wedge-shaped defects on the same exposed cervical dentin surface of a hypersensitive tooth. A new biopsy technique that makes use of a hollow, cylindrical diamond bur was designed so that specimens from exposed root dentin of vital teeth could be obtained. Twenty-two dentin biopsy pairs were divided into two groups; one was prepared for scanning electron microscopy (SEM) and the other for microradiography (MR). Small hypersensitive areas were identified by a scratch test on exposed human dentin in vivo. SEM observation of the dentin biopsies showed that the orifices of many dentinal tubules in hypersensitive areas were open and that membranous structures appeared on the walls of dentinal tubules. In naturally desensitized areas on the same dentin surface, most of the dentinal tubules were obturated with rhombohedral crystals of all sizes; membranous structures were not observed in these tubules. These results showed that hypersensitivity occurred on the exposed dentin when most of the tubular orifices were open.     

A scanning electron microscopic study of different caries removal techniques on human dentin

Scanning electron microscopy (SEM) evaluated the effect of different caries removal techniques on human dentin topography. Thirty-six extracted human carious mandibular molars were randomly assigned to six groups according to caries removal technique. Carious tissue was removed by hand excavation, bur excavation, air-abrasion, laser ablation, chemomechanical methods and sono-abrasion. The remaining dentin surfaces were replicated and gold-coated. The surfaces were examined using SEM and distinct differences in appearance were observed among specimens treated with different caries removal techniques. While hand-excavated, bur-excavated and air-abraded carious dentin surfaces were covered with a residual smear layer, sono-abrasion with patent dentinal tubules completely removed the smear layer. A few patent orifices of dentinal tubules were observed in dentin subjected to laser ablation and chemo-mechanical caries removal.     

草酸钾对牙本质小管堵塞作用的实验研究

应用扫描电镜、能谱分析技术研究草酸钾对离体牙本质脱敏试验的结果,表明草酸钾有良好的堵塞牙本质小管作用,实验标本表面钙化程度明显提高.     

A novel rapidly mineralized biphasic calcium phosphate with high acid-resistance stability for long-term treatment of dentin hypersensitivity

ObjectivesTreating dental hypersensitivity (DH) rapidly and maintaining long-term effectiveness remains challenging. We aimed to address this problem by fabricating a novel rapidly mineralized biphasic calcium phosphate (RMBCP), which could rapidly elicit mineralization to form hydroxyapatite (HA) and perform excellent acid-resistant stability, thus effectively blocking the exposed dental tubules and protecting them from acid attack.MethodsRMBCP was firstly synthesized by precisely adjusting the molar ratio of acetic acid and calcium hydroxide and characterized by X-ray diffraction (XRD), X-ray fluorescence microprobe (XRF), Fourier-transform infrared (FTIR) spectrometer, scanning electron microscope (SEM), and transmission electron microscope (TEM). Subsequently, using a commercialized desensitizing agent, 45S5 bioglass (BG), as the control group, the mineralization performance of RMBCP was investigated in simulated body fluid (SBF), Dulbecco's modified eagle medium (DMEM), and even slightly acidic artificial saliva (pH=6.6). Moreover, the biocompatibility of RMBCP was studied. Finally, the tubule occlusion effect and acid-resistant stability of RMBCP were evaluated in vitro and in vivo.ResultsThe rapid mineralization behavior of RMBCP could easily adhere to the dentin surface and block the dentinal tubules completely in vitro and in vivo within 7days. RMBCP performed high acid-resistant stability to maintain the long-term therapeutic effect of DH treatment.SignificanceDeveloping novel bioactive calcium phosphate materials with the ability to trigger mineralization for HA formation rapidly will be an effective strategy for the long-term treatment of dentin hypersensitivity.     

Transmission electron microscopic characterization of hypersensitive human radicular dentin

Transmission electron microscopy (TEM) and x-ray microanalysis (XMA) were used for the study of the ultrastructure of the lumens of dentinal tubules in superficial layers of dentin specimens obtained by use of a new biopsy technique from both hypersensitive and naturally desensitized areas of exposed root surfaces, in vivo. The TEM images showed clearly that the lumens of most of the tubules were occluded with mineral crystals in naturally desensitized areas, but such lumens were empty and surrounded with peritubular and intertubular dentin in hypersensitive areas. Moreover, electron-dense structures that lined peritubular dentin were observed in the empty lumens of dentinal tubules.