A clinical evaluation of posterior composite resin restorations

There is a trend towards manufacturers seeking to provide dentists with a single, all-purpose composite resin, usually of the small particle hybrid type. This three-year clinical study compared the clinical performance of three different types of composite resin used in posterior teeth and identified several modes of failure. Of the 330 restorations (three composite resins and one amalgam control) initially placed in 72 patients, 223 restorations in 48 patients were available for evaluation at three years. Modified clinical criteria for assessing the restorations were able to discriminate among the composite resins. A microfilled composite and a small particle hybrid exhibited increasing evidence of marginal fracture (crevice) with time. In addition, the small particle hybrid showed evidence of wear at the margins more frequently than the other materials. Of the restorations available for assessment, four restorations of each of these two types of composite resin required replacement during the study. Coarse particle hybrid restorations showed evidence of wear but little evidence of marginal fracture.     

The effectiveness of different polymerization protocols for class II composite resin restorations

OBJECTIVES: To investigate the effect of reduced light exposure times on Vickers hardness (VH) of class II composite resin restorations. METHODS: Class II restorations were made in vitro in three 2mm thick increments in a human molar. Two composite resins (Clearfil AP-X; Esthet-X) were polymerized with four light-curing units (Halogen; Astralis 10, LED; The Cure, L.E.Demetron I, Smartlite) following four curing protocols. Three protocols with exposure times of 10s, 20s or 40s (control) per layer. In the fourth protocol, 10s irradiation per layer was combined with additional lateral curing for 10s from buccal and palatal after removal of the metal matrix. VH of the axial surface was determined at top and bottom layers directly after light-curing and after 7 days storage. Linear regression analysis was performed to analyze the effect of protocol variables. RESULTS: Directly after light-curing VH of both composite resins was significantly influenced by curing protocols. After 7 days, curing protocols had no significant effect on VH of Clearfil AP-X, except for the Smartlite. VH of Esthet-X was still influenced by curing protocol, but differences were smaller than directly after light-curing. CONCLUSIONS: With high intensity light-curing units, exposure times of 10s/2mm increment can be sufficient to obtain under in vitro conditions a high degree of conversion, depending on materials and curing protocols. With additional lateral curing of a class II composite resin restoration a higher degree of cure can be obtained in less time.     

Clinical strategies for esthetic excellence in anterior tooth restorations: understanding color and composite resin selection

Direct composite resin restorations have become a viable alternative for patients that require anterior restorative procedures to be integrated to the other teeth that compose the smile, especially for presenting satisfactory esthetic results and minimum wear of the dental structure. Technological evolution along with a better understanding of the behavior of dental tissues to light incidence has allowed the development of new composite resins with better mechanical and optical properties, making possible a more artistic approach for anterior restorations. The combination of the increasing demand of patients for esthetics and the capacity to preserve the dental structure resulted in the development of different incremental techniques for restoring fractured anterior teeth in a natural way. In order to achieve esthetic excellence, dentists should understand and apply artistic and scientific principles when choosing color of restorative materials, as well as during the insertion of the composite resin. The discussion of these strategies will be divided into two papers. In this paper, the criteria for color and material selection to obtain a natural reproduction of the lost dental structures and an imperceptible restoration will be addressed.     

Boron nitride nanosheets modified with zinc oxide nanoparticles as novel fillers of dental resin composite

ObjectiveThe purpose of this study was to synthesize boron nitride nanosheets modified with zinc oxide nanoparticles (BNNSs/ZnO) and incorporate them as a novel inorganic filler to get an antibacterial dental resin composite.MethodsThe BNNSs/ZnO nanocomposites were synthesized via the hydrothermal method and characterized by Field Emission Scanning Electron Microscope (FESEM), Transmission Electron Microscopy (TEM), Energy Dispersive Spectrometer (EDS), X-ray Diffraction (XRD) and Fourier Transform-Infrared (FTIR) Spectroscopy. The BNNSs/ZnO or BNNSs were added into the experimental dental composite with different proportions, respectively. The mechanical and physical properties of the modified dental composite were evaluated. Their antibacterial activities were also assessed by quantitative analysis using Streptococcus mutans (S. mutans).ResultsThe BNNSs/ZnO nanocomposites were successfully synthesized, and the growth of ZnO nanoparticles (ZnO NPs) on boron nitride nanosheets was confirmed. The flexural strength (FS), flexural modulus (FM) and the compressive strength (CS) of all modified resin composites showed no change compared to the control group. The curing depth, degree of conversion, water absorption and solubility of the modified composites were still within the clinical requirement. The antibacterial rates of the modified composites were significantly increased compared to the control group, which can reach 98 % when 0.5 % BNNSs/ZnO was added.SignificanceThe modified dental resin composite with novel BNNSs or BNNSs/ZnO fillers shows significantly high antibacterial activity with suitable physicochemical and mechanical properties.     

Clinical performance of a hybrid resin composite with and without an intermediate layer of flowable resin composite: A 7-year evaluation

Objective

The objective of this prospective clinical follow up was to evaluate the long term clinical performance of a hybrid resin composite in Class II restorations with and without intermediate layer of flowable resin composite.

Methods

Each participant received at least two, as similar as possible, Class II restorations of the hybrid resin composite. One resin composite restoration of each pair (59) was chosen at random to be restored with an intermediary layer with flowable resin composite. The other was restored without. The 118 restorations were evaluated using slightly modified USPHS criteria at baseline and then yearly during 7 years.

Results

Four drop outs were registered during the 7-year follow up (2 with and 2 without flowable) restorations. A prediction of the caries risk showed that 18 of the evaluated 46 patients were considered as high risk patients. Seventeen failures were observed, 8 in restorations with and 9 in restorations without an intermediate layer of flowable resin composite, resulting in a 14.9% failure rate after 7 years. The main reasons for failure were: fracture of resin composite (8), secondary caries (4) and cusp fracture (3). No statistical difference was seen between restorations restored with and without flowable layer.

Conclusion

The hybrid resin composite showed a good clinical performance during the 7-year evaluation. The use of flowable resin composite as an intermediate layer did not result in improved effectiveness of the Class II restorations.     

Anterior Z250 resin composite restorations: one-year evaluation of clinical performance

The purpose of this practice-based study was to compare the clinical performance of a new universal composite resin material (Z250) used for Class III and V cavities in anterior teeth. Restorative materials (Z250 and Z100; 3 M ESPE) placed by six operators were used for a total of 150 restorations during the 6-month enrollment period. After 1 year, 141 restorations (76 Z250 and 66 Z100) were available and evaluated for overall quality, color match, marginal adaptation, surface appearance and the presence of secondary caries, using modified USPHS criteria. The overall quality was excellent for both materials and no significant changes were noted during the follow-up. None of the scores between the two materials were statistically significant. Major changes were seen in color match and surface appearance. At baseline, the color match of 71% of Z250 and 62% of Z100 was rated as Alfa, after 1 year the figures were 60 and 65%. Regarding surface appearance, 97% of the Z250 were rated Alfa at baseline, whereas at 1 year the figure was 76%. For Z100, the scores were 94 and 79%, respectively. After 1 year, the clinical performance of Z250 restorative composite resin was clinically acceptable and similar to that of Z100.     

Press-on force during polishing of resin composite restorations

ObjectiveTo measure the press-on force during the polishing of composite restorations carried out by 10 dentists in a clinically simulated procedure.MethodsComposite restorations (Tetric EvoCeram Bulk Fill) were placed in standardized Class II two-surface cavities in first upper acrylic molars. The surfaces were roughened by sandblasting (50 μm, 1 bar). The tooth was mounted on a tailor-made device with a 3D force sensor (Kistler, Z21134-300, 10H z). Ten dentists (7 male, 3 female) polished one Class II restoration each using the one-step polishing system OptraPol together with a dental handpiece and water spray. The dentists were allowed to use all shapes of the polishing system (small flame, large flame, cup, lens). During polishing, the press-on forces measured for up to 2 minutes. Simultaneously, the polishing procedure was recorded with a digital camera to correlate the forces with the polishing shapes and movements.ResultsIn total, 17,999 force measurements were available for analysis. The mean forces of all operators varied between 0.77(±0.63) N and 2.23(±1.48) N; the difference was statistically significant (ANOVA, post-hoc Tukey B, p < 0.05). All dentists exerted maximum forces higher than 3 N (between 3.3 N and 18.3 N). Force values exceeded 2 N during 25% of the polishing time. Female dentists polished with a statistically significant lower force than male dentists (ANOVA, p < 0.001). Polishing with the large flame and the cup generated significantly higher forces than polishing with the small flame and the lens (ANOVA, post hoc Tukey B, p < 0.01).ConclusionsThe press-on forces applied during polishing varied significantly between dentists and within the same dentist. In about 25% of the polishing time, forces were above the 2 N limit, which is recommended by some manufacturers as the maximum polishing force. Test institutes and manufacturers should evaluate the polishing performance of polishing instruments with various press-on forces.     

排龈技术在牙体缺损修复中的应用

目的观察排龈对3MZ250复合树脂修复牙体缺损疗效的影响。方法选择31例120颗唇颊面牙颈部龋缺损牙,随机分为实验组和对照组,每组60颗,经窝洞预备后,实验组排龈线排龈后3MZ250复合树脂修复,对照组直接树脂修复,随访2年,评价修复体保存、继发龋以及边缘密合状况。结果充填后1周复查,使用排龈线组修复后悬突的发生率低于对照组,差异有显著性（P〈0．01）。充填后0．5年复查两组脱落率无明显差异;1年及2年后复查实验纽充填体的脱落率明显低于对照组（P〈0．05）。结论排龈可提高3MZ250复合树脂修复牙体缺损的修复体保存率,可以作为一项常规使用措施。     

不同抛光时机对复合树脂边缘微渗漏的影响

目的:评价不同抛光时机对不同种类树脂边缘微渗漏的影响。方法:选择80颗离体恒前磨牙,在每颗牙的颊侧颈部釉牙骨质界处用高速涡轮机制备盒形单面洞,长和宽均为3mm,洞深2mm。按照使用树脂充填的种类分为Filtek Z350充填组和Filtek Z250充填组,每组再按照抛光与否及抛光时机分为不抛光组、充填后即刻抛光组、充填10min后抛光组和充填24h后抛光组。使用Sof-lex discs抛光系统对树脂进行抛光。实验样本经冷热循环后,在2%亚甲基蓝溶液中浸泡24 h,沿牙体长轴将充填体正中颊舌向纵行剖开,立体显微镜下观察剖面,采用Spot version4.6图像分析软件测量微渗漏深度。采用SPSS 17.0软件包对各组的微渗漏程度和深度分别进行Mann-Whitney U检验和Kroskal-Walis秩和检验。结果:Filtek Z350各组的边缘微渗漏深度分别为(0.655±0.486)mm、(0.626±0.497)mm、(0.648±0.370)mm和(0.639±0.453)mm。Filtek Z250各组的边缘微渗漏深度分别为(0.785±0.553)mm、(0.763±0.491)、(0.74...     

Restoration techniques and marginal overhang in Class II composite resin restorations

Objectives

The objective of the study was to compare in vitro interproximal overhang formation of Class II composite resin restoration when using different matrix systems.

Methods

240 lower left molar phantom head teeth with an MO-preparation were divided into 12 groups (n = 20). In six groups a circumferential matrix (Tofflemire X-thin matrix, HaweNeos 1001-c, SuperCap) was used, combined with either a hand-instrument (PFI49 or OptraContact) or separation ring (Composi-Tight Gold). In the other six groups two sectional matrix systems were used (flexible and dead-soft), with three separation rings (Composi-Tight Gold, Contact Matrix, Palodent BiTine). Matrices were secured with wooden wedges and preparations were restored with composite resin Clearfil AP-X (Kuraray) placed and polymerized in increments. After matrix removal overhang was measured on a standardized digital macroscopic image in mm². For analysis a multiple linear regression model was used.

Results

Use of circumferential matrices resulted in less overhang than sectional matrices (−0.85 mm², p < 0.001). A flexible matrix led to less overhang than dead-soft matrices (−0.54 mm², p < 0.001), and no difference was found between straight and pre-contoured matrices (p = 0.945). The insertion of the OptraContact resulted in a much increased overhang of 2.54 mm² (p < 0.001). The Composi-Tight Gold and the Contact Matrix System rings resulted in less overhang, −0.69 and −0.68 mm², respectively (both p < 0.001), whereas the Palodent BiTine ring did not.

Conclusions

Use of circumferential matrices or sectional flexible matrices resulted in the least marginal overhang when combined with a Contact Matrix separation ring or a Composi-Tight Gold ring.     

个性化复合树脂分层修复比色板的设计与临床应用

目的 为方便临床医师在应用复合树脂修复牙齿缺损时进行比色,设计一种牙科复合树脂分层修复比色系统.方法 本比色系统包括比色板底板,复合树脂比色片及比色片制作模具3个部分,可以实现对牙齿不同位置进行精准比色并定量明确各区域所使用树脂的种类及对应的厚度.选取54名患者的87颗缺损前牙,分别使用个性化比色板+分层复合树脂修复及...     

含固位型填料光固化复合树脂的流变特性

目的　探讨含固位型填料 (retentivefiller,RF)复合树脂的流变性及其与普通填料复合树脂的差异。方法　采用动态应力流变仪DSR 2 0 0 ,在室温 (2 5℃ )时测试含固位型填料复合树脂和普通填料复合树脂的流变性 ,包括黏度、剪切应力和柔量。结果　含固位型填料复合树脂的黏度大于普通填料复合树脂 (P <0 0 1)。随剪切应力的增大 ,前者的黏度开始基本保持不变 ,而后者会降低 ;当剪切应力大于 2 0 3 18Pa时 ,两者的黏度随剪切应力的增大而增加 ;含固位型填料复合树脂的柔量明显小于普通填料复合树脂者 (P <0 0 1)。结论　两种复合树脂的流变性有较大差异 ,因而其临床应用特性也有所不同。     

Four-year clinical evaluation of Class II nano-hybrid resin composite restorations bonded with a one-step self-etch and a two-step etch-and-rinse adhesive

Objective

The objective of this prospective clinical trial was to evaluate the 4-year clinical performance of an ormocer-based nano-hybrid resin composite (Ceram X; Dentsply/DeTrey) in Class II restorations placed with a one-step self-etch (Xeno III; Dentsply/DeTrey) and two-step etch-and-rinse adhesive (Ivoclar Vivadent).

Methods

Seventy-eight participants received at random at least two, as similar as possible, Class II restorations of the nano-hybrid resin composite bonded with either a single step self-etch adhesive or a control 2-step etch-and-rinse adhesive. The 165 restorations were evaluated using slightly modified USPHS criteria at baseline and then yearly during 4 years.

Results

162 restorations were evaluated at 4 years. Postoperative sensitivity was observed in 6 patients (3 Xeno III, 3 Exite) between 1 and 3 weeks. Eleven failed restorations (6.8%) were observed during the follow up. Seven in the one-step self-etch adhesive group (7.7%) and four in the 2-step etch-and-rinse group (5.6%). This resulted in non-significant different annual failure rates of 1.9% and 1.4%, respectively. Fracture of restoration was the main reason for failure.

Conclusion

The ormocer-based nano-hybrid resin composite showed a good clinical performance in Class II cavities during the 4 year evaluation. No significant difference was seen in overall clinical effectiveness between the two adhesives.     

加纤维氧化锌丁香油膏力学试验和临床应用

通过对加纤维氧化锌丁香油膏（以下称加纤维下氧膏）的力学性进行评价,发现其抗压、抗拉力、抗剪切力等物理性能明显优于未另纤维氧化锌丁香膏（以下称加纤维丁氧膏）。将其应用于临床４００例Ｉ－Ｖ洞暂封,其抗松动、破损,脱落明显优于未加纤维丁膏,这是提示加纤维丁氧膏作为临床暂封材料可减少失活剂的露渗和脱落。     

3种抛光方法对2种复合树脂边缘微渗漏的影响

目的评价3种抛光方法对2种复合树脂边缘微渗漏的影响。方法选择80颗离体恒前磨牙,在每颗牙的颊侧颈部釉-牙骨质交界处用高速涡轮机制备盒形单面洞,长和宽均为3 mm,洞深2 mm。使用3M Z350树脂和3M Z250树脂各充填40颗牙。按照充填材料不同,随机分为不抛光组、Sof-lex discs抛光系统组、Super-snap抛光系统组和金刚砂抛光车针修形后再用橡皮杯抛光组。实验样本冷热循环后,在2%亚甲基蓝溶液中浸泡 24 h,沿牙体长轴将充填体正中颊舌向纵行剖开,立体显微镜（×40）下观察剖面,采用Spot 4.6图像分析软件测量渗漏深度。采用 SPSS 17.0 软件包对各组的微渗漏程度和深度分别进行Mann-Whitney U 检验和Kroskal-Walis秩和检验。结果3M Z350各组的边缘微渗漏深度分别为（0.655±0.486）、（0.626±0.497）、（0.634±0.345）和（0.875±0.283） mm。3M Z250各组的边缘微渗漏深度分别为（0.785±0.553） mm、（0.763±0.491） mm、（0.789±0.308）mm和（0.942±0.318） mm。2种树脂充填后,3种抛光方法树脂边缘微渗漏程度和深度均有显著差异（P<0.05）。结论Sof-lex discs抛光系统、Super-snap抛光系统对复合树脂修复体边缘渗漏无显著影响。     

Zirconia-incorporated zinc oxide eugenol has improved mechanical properties and cytocompatibility with human dental pulp stem cells

Objective

Zinc oxide eugenol (ZOE) is widely used as a therapeutic dental restorative material. However, ZOE has poor mechanical properties and high cytotoxicity toward human dental pulp stem cells (hDPSCs) due to the release of Zn ions. In this study, zirconia-incorporated ZOE (ZZrOE) was developed to reduce the cytotoxicity and improve the mechanical properties of ZOE with sustained therapeutic effects on inflamed hDPSCs in terms of inflammatory gene expression levels compared with those of the original material.

自酸蚀粘接系统和复合树脂修复牙体缺损的疗效比较

目的:比较自酸蚀粘接系统和复合树脂修复牙体缺损的效果。方法:随机抽取201颗患牙随机分为2组,治疗组101颗,采用自酸蚀底料的可乐丽菲露SEBOND及AP-X复合树脂修复牙体缺损;对照组100颗,应用Durafill釉质粘接剂及Charisma复合树脂修复。治疗后随访观察1、3、6个月,所得结果用四格表χ2检验。结果:治疗组修复体成功率达98%,而对照组则为90%,两组疗效有显著差异(P<0.05)。结论:应用自酸蚀粘接系统和复合树脂修复牙体缺损,可以获得较好的固位性能和边缘封闭性,值得在临床上推广。     

不同复合树脂对瓷和树脂黏结强度的影响

目的:比较不同光固化复合树脂对瓷和树脂黏结强度的影响。方法:将3种光固化复合树脂黏固于经过表面处理的瓷表面,制成黏结试件,进行剪切强度测试。结果:Charisma、Esthet-X、AP-X三种树脂与瓷之间产生的黏结强度分别为15. 46、36. 39、25. 72MPa。结论:AP-X树脂与瓷之间的黏结性能较好,但对操作技术较为敏感。     

Effect of different composite modulation protocols on the conversion and polymerization stress profile of bulk-filled resin restorations

ObjectiveThe aim of this in vitro study was to test the effect of different composite modulation protocols (pre-heating, light-curing time and oligomer addition) for bulk filling techniques on resin polymerization stress, intra-pulpal temperature change and degree of conversion.MethodsClass I cavities (4 mm depth × 5 mm diameter) were prepared in 48 extracted third molars and divided in 6 groups. Restorations were completed with a single increment, according to the following groups: (1) Filtek Z250XT (room temperature – activated for 20 s); (2) Filtek Z250XT (at room temperature – activated for 40 s); (3) Filtek Z250XT (pre-heated at 68 °C – activated for 20 s); (4) Filtek Z250XT (pre-heated at 68 °C – activated for 40 s); (5) Filtek BulkFill (at room temperature – activated for 20 s); (6) Filtek Z250XT (modified by the addition of a thio-urethane oligomer at room temperature – activated for 40 s). Acoustic emission test was used as a real-time polymerization stress (PS) assessment. The intra-pulpal temperature change was recorded with a thermocouple and bottom/top degree of conversion (DC) measured by Raman spectroscopy. Data were analyzed with one-way ANOVA/Tukey's test (α = 5%).ResultsPre-heating the resin composite did not influence the intra-pulpal temperature (p = 0.077). The thio-urethane-containing composite exhibited significantly less PS, due to a lower number of acoustic events. Groups with pre-heated composites did not result in significantly different PS. Filtek BulkFill and the thio-urethane experimental composite presented significantly higher DC.SignificanceResin composite pre-heating was not able to reduce polymerization stress in direct restorations. However, thio-urethane addition to a resin composite could reduce the polymerization stress while improving the DC.     

Marginal leakage in direct and indirect composite resin restorations in primary teeth: an in vitro study

OBJECTIVE: The aim of this study was to evaluate the marginal leakage in class II preparations, with margins in enamel, restored with composite resin indirect and direct restorations. METHODS: Twenty extracted primary molars were chosen and divided at random into two groups: G1 (n=10) restored by a direct technique and G2 (n=10) restored by an indirect technique. The composite resin Filtek Z250 (3M) and the Adper Single Bond adhesive (3M) were used in both groups. Teeth were stored in a humid environment at 37 degrees C for 1 week, thermo cycled (500 cycles, 5 degrees C and 55 degrees C), sealed and immersed in a 0.5% basic fuchsine dye for 24h. Teeth were longitudinally sectioned, in a mesio-distal direction and leakage was assessed. RESULTS: No leakage in the specimens from G2 and leakage in four specimens from G1, but the Mann-Whitney test showed that there was no statistically significant difference between the groups, either for occlusal box (p=0.317) and proximal box (p=0.067). CONCLUSION: This study demonstrated that direct and indirect class II composite resin restorations with cervical margins in enamel show similar results regarding marginal leakage.