A randomized double-blind clinical trial of posterior composite restorations with or without bevel: 1-year follow-up

Objective

This randomized double-blind clinical trial compared the performance of posterior composite restorations with or without bevel, after 1-year follow-up.

Material and Methods

Thirteen volunteers requiring at least two posterior composite restorations were selected. Twenty-nine cavities were performed, comprising 14 without bevel (butt joint) and 15 with bevel preparation of the enamel cavosurface angle. All cavities were restored with simplified adhesive system (Adper Single Bond) and composite resin (Filtek P60). A halogen light curing unit was used through the study. Restorations were polished immediately. Analysis was carried out at baseline, after 6 months and after 1 year by a calibrated evaluator (Kappa), according to the FDI criteria. Data were statistically analyzed by Mann-Whitney test (p<0.05).

Results

Beveled and non-beveled cavities performed similarly after 1 year follow-up, regarding to fractures and retention, marginal adaptation, postoperative hypersensitivity, recurrence of caries, surface luster and anatomic form. However, for surface and marginal staining, beveled cavities showed significantly better performance (p<0.05) than butt joint restorations.

Conclusions

It was concluded that the restorations were acceptable after 1 year, but restorations placed in cavities with marginal beveling showed less marginal staining than those placed in non-beveled cavities.     

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.     

Simulating the shrinkage-induced interfacial damage around Class I composite resin restorations with damage mechanics

ObjectivesTo investigate the shrinkage-induced damage at the composite-tooth interface by finite element analysis (FEA) using the cohesive zone model (CZM).MethodsAxisymmetric models of Class I restorations were created to illustrate the interfacial damage around composite resin restorations of different dimensions, with polymerization shrinkage modeled analogously to thermal shrinkage. The damage to the adhesive interface was determined using a CZM based on the fracture strength and fracture energy. To show the effects of damage, conventional models with perfectly bonded composite resin restorations were created as controls.ResultsThe results indicated interfacial damage at the butt-joint cavosurface margin, dentinoenamel junction, and internal line angle. The percentage of damaged interfacial area was found to increase with decreasing diameter for restorations of the same height. For a given diameter, the damage was more severe for restorations of greater depth. The effects of the damage were further illustrated in the model with a restoration of 2-mm diameter and height. The interfacial damage occurred primarily at the internal line angle (83.3 % of all the damaged interfacial area), leading to local stress relief (from 18.3 MPa to 12.8 MPa), but also higher stress at the damage fronts. Greater local shrinkage was found in composites adjacent to the damage.SignificanceThe damage mechanics-based CZM is an essential refinement of the FEA to predict interfacial damage and its implications. The extent of damage was found to be greater around restorations with smaller diameters and greater depths. The entire simulation is available via an open-source platform to facilitate further applications in adhesive dentistry.     

Class II composite restorations with metallic and translucent matrices: 2-year follow-up findings

OBJECTIVE: The aim of this randomized, clinical study was to evaluate the performance of composite restorations placed with two matrix and wedge systems after a 2-year follow-up. METHODS: Twenty-three patients were selected, and received at least two Class II restorations, one with metallic matrix and wooden wedge and other with polyester matrix and reflective wedge. One dentist placed all the 109 restorations. All cavities were restored using Single Bond and P-60 (3M ESPE), according to manufacturer's instructions. In the metal matrix group, polymerization was performed from occlusal, and in the polyester group, through the reflective wedge. Restorations were evaluated at baseline and after 12 and 24 months by the modified USPHS criteria, and data were analyzed with Mann-Whitney and Wilcoxon Signed Rank tests (alpha=0.05). RESULTS: Fifteen subjects and 78 restorations were re-evaluated after 24 months. A significant decrease in the quality of cervical adaptation and proximal contacts by radiographic evaluation was evidenced (p<0.05), but no differences between the two matrix systems were detected (p>0.05). In the clinical evaluation there were no significant differences between matrices after 2 years (p>0.05). A compromising of marginal adaptation, marginal staining and proximal contacts aspects for both matrix systems was evidenced, and restorations placed with translucent matrices showed loss of color stability (p<0.05). CONCLUSIONS: Whereas restorations presented some clinical aspects somewhat compromised after 2 years, the matrix and wedge systems evaluated showed similar clinical performance.     

Flowable resin composite as a class II restorative in primary molars: A two-year clinical evaluation

Objective. To evaluate the clinical durability of flowable resin composite and resin-modified glass ionomer cement when used as class II restoratives in primary molars. Material and Methods. A total of 190 restorations were placed in 61 children, age in the range of 5–11 years. The restoratives, Tetric Flow, in combination with the adhesives, Excite or Prompt-L-Pop and Vitremer, were used in class II cavities in primary molars. An intra-individual study design was used and the restorations were evaluated by modified USPHS criteria over a 2-year period. Results. 146 of the restorations could be evaluated at 2 years. The cumulative failure rate was 10.6% for Vitremer and 13.6% for Tetric Flow. No statistically significant differences were found in failure rates between different materials or between bonding systems. The main cause of failure for Tetric Flow was secondary caries and for Vitremer wear and dissolution. Conclusions. Vitremer and Tetric Flow showed no significant difference concerning clinical durability at 2 years when used as class II restoratives in primary molars. Both materials demonstrated acceptable clinical results.     

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.     

A prospective randomised clinical trial of one bis-GMA-based and two ormocer-based composite restorative systems in class II cavities: three-year results

OBJECTIVES: Ormocer composites, consisting of a silicon-based polymer, have been developed recently as a tooth-coloured restorative material. The purpose of this prospective randomised clinical trial was to evaluate the performance of two small-particle hybrid ormocer-based restorative systems (AD, Admira/Admira Bond, VOCO; DE, Definite/Etch & Prime 3.0, Dentsply) and one small-particle hybrid bis-GMA-based composite restorative system (TC, Tetric-Ceram/Syntac, Ivoclar-Vivadent) in occlusal stress-bearing restorations. METHODS: One hundred and twenty-eight occlusal-proximal restorations (44 AD, 43 DE and 41 TC) were placed according to the manufacturer's instructions in thirty-two adult patients. Their clinical performance was scored according to the USPHS criteria and evaluation of bite-wing radiographs. RESULTS: After 3 years, four AD, five DE and four TC restorations had failed due to fracture or marginal gap formation. Surface roughness improved significantly when compared to the baseline in AD and TC (Friedman test, p<0.05) during the first year but returned to baseline values after 3 years. DE had a significant tendency towards discolouration (p<0.05). Bite-wing radiographs showed two AD and one TC restorations with internal porosities. ANOVA showed that larger restorations (> or = 3 surfaces) showed significantly more degradation than smaller ones. CONCLUSIONS: In a group of class II restorations, there was no significant difference in failures after 3 years between ormocer-based and bis-GMA-based restorative systems.     

A prospective randomized clinical trial of one bis-GMA-based and two ormocer-based composite restorative systems in class II cavities: Five-year results

Objectives

Ormocer composites, consisting of a silicon-based polymer, have been developed recently as a tooth-colored restorative material. The purpose of this prospective randomized clinical trial was to evaluate the performance of two small-particle hybrid ormocer-based restorative systems (AD, Admira/Admira Bond, VOCO; DE, Definite/Etch & Prime 3.0, Dentsply) and one small-particle hybrid bis-GMA-based composite restorative system (TC, Tetric-Ceram/Syntac, Ivoclar-Vivadent) in class II cavities.

Methods

From 128 occlusal-proximal restorations (44 AD, 43 DE and 41 TC) placed in 32 adult patients, eventually 77 (22 AD, 29 DE and 26 TC) remained available for evaluation after 5 years. Their clinical performance was scored according to the USPHS criteria and evaluation of bite-wing radiographs.

Results

After 5 years, eight AD, six DE and seven TC restorations had failed (p = 0.10, log-rank test). The main reason was fracture or marginal gap formation, while secondary caries accounted for four failures. In all restorations the quality of surface, margins and contact point decreased significantly compared to baseline. DE had a significant poorer color match (p < 0.01). Statistical evaluation using the KW test showed that failures were concentrated on specific patients.

Conclusions

In a group of class II restorations, there was no significant difference in failures after 5 years between ormocer-based and bis-GMA-based restorative systems.     

Class I and II composite resin restorations: 4-year clinical follow up

The clinical properties and longevity of two posterior composite materials were studied during a 4-year period. 137 Class I and II restorations in 65 patients were evaluated directly using USPHS criteria. Araldite casts were used to categorize quantitatively the amount of occlusal wear according to the Leinfelder method. No differences could be found between the two materials regarding clinical properties and failure rate. The overall success rate was high (84%). The average occlusal deterioration after 4 years was about 140 microns.     

Nanofilled and microhybrid composite restorations: Five-year clinical wear performances

Objectives

To compare the clinical wear performance of nanofilled restorations (Filtek Supreme) against microhybrid restorations (Z100) in a 5-year randomized clinical trial to evaluate the wear rate and the influence of subject-, operator- and restoration-related variables on wear rate.

Materials and methods

18 Filtek Supreme and 17 Z100 restorations were placed in human molars (split-mouth-model) and bonded with Single Bond/Scotch Bond Adhesive. Restorations were recalled at baseline, 6-, 12-months and at annual intervals until 5-years of clinical service. The gypsum replicas at each recall were used for 3D-Pro-laser scanning to quantify wear and the epoxy resin replicas were observed under SEM for microwear patterns. Linear-mixed-models were used to study the influence of the different variables on the vertical and volume loss.

Results

		Z100	Filtek Supreme
Vertical wear (μm/month)	Generalised	0.870	0. 925
	0-6 m/running-in wear	5.563	6.987
	6-36 m/early stage	0.974	1.288
	36-60 m/steady state	0.486	0.263
Volume loss (mm3/month)	Generalised	0.014	0.011
	0-6 m/running-in wear	0.017	0.011
	6-36 m/early stage	0.006	0.005
	36-60 m/steady state	0.031	0.023

Full-size table

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12.

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

《Dental materials》2020,36(7):829-837

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.     

13.

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余擎  齐春子  姜永 《中国实用口腔科杂志》2009,2(12):705-708

提要：复合树脂直接修复技术在现阶段临床已广泛应用,有关其修复治疗后的临床疗效已有很多报道。本文介绍了有关复合树脂直接修复技术的临床疗效评估方法、标准及影响因素,为临床实际和疗效观察提供参考。     

14.

两种充填方式对不同光固化复合树脂充填体内孔隙的影响     

赵信义  张武  Sean Lee  陆梅  李一鸣 《中华口腔医学杂志》2010,45(1)

目的 探讨光固化复合树脂的稠度及充填方式对充填体内孔隙的影响,以期为复合树脂的临床应用提供参考.方法 6位操作者将3种复合树脂(树脂A:Prodigy;树脂B:Tetric EvoCeram;树脂C:Tetric Ceram HB)以器械充填和注射充填的方式充填入模拟I类洞中,将充填体纵向片切成0.5 mm厚的切片,测定切片内孔隙数量;并测试未进行充填的复合树脂内的固有孔隙数量.结果 未充填的复合树脂内固有孔隙数量极少(≤5个);稠度居中的树脂B的孔隙数量[器械充填和注射充填分别为(1137.1±365.0)和(566.1±206.4)个]远多于稠度最大的树脂C[分别为(193.1±35.8)和(156.3±33.0)个]和稠度最小的树脂A[分别为(241.0±116.1)和(195.8±28.7)个,P<0.05).树脂B器械充填的孔隙数量明显多于注射充填(P<0.05),而树脂A和C两种充填方式的孔隙数量差异均无统计学意义(P>0.05).结论 复合树脂充填体内的孔隙基本是在充填过程中形成的,孔隙数量与复合树脂稠度无线性关系;并非所有复合树脂用注射充填均能显著减少充填体内孔隙数量.     

15.

A five-year clinical evaluation of Class II composite resin restorations   总被引：5，自引：0，他引：5  

Köhler B  Rasmusson CG  Odman P 《Journal of dentistry》2000,28(2):111-116

OBJECTIVES: To study the clinical efficacy of posterior composite resin restorations placed in general practice after five years. METHODS: Two commercial composite resin systems were used. Three general practitioners placed the restorations at a Public Dental Health Service Office. The patients were not selected specifically for this study. Class II cavities were restored with Superlux Molar and P-50 APC composite systems on an alternate basis. At baseline, 63 restorations were placed in molars and premolars in 45 patients. For primary caries, generally a conservative cavity design was used (n = 23), while replacements of amalgams resulted in the larger conventional Class II design (n = 40). The restorations were assessed using a modified USPHS criteria. Wear measurements were determined by the Leinfelder method. Photographs and bite-wing radiographs were taken to supplement the clinical evaluation of colour match, marginal adaptation and recurrent caries. Saliva sampling was performed to determine the rate of secretion and the level of mutans streptococci and lactobacilli. RESULTS: At the five-year review 51 restorations were available for examination, of which nine restorations were rated clinically unacceptable. Including the failed restorations (n = 7), at the three-year review, a total of 16 restorations had failed (27.6%) over a five-year period. The most common reasons for failure were recurrent caries (n = 7) and marginal defects (n = 4). The mean wear of Superlux Molar was 167 microns and of P-50 APC 158 microns. Eight of the 11 patients with failed restorations due to caries and marginal defects had high counts of mutans streptococci at baseline. CONCLUSIONS: The failures in the present group of patients did not specifically relate to material, tooth type or cavity design. However, it is suggested that patient factors such as caries activity should be monitored and managed.     

16.

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

Närhi TO  Tanner J  Ostela I  Narva K  Nohrström T  Tirri T  Vallittu PK 《Clinical oral investigations》2003,7(4):241-243

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.     

17.

Influence of chlorhexidine digluconate on the clinical performance of adhesive restorations: A 3-year follow-up     

Neimar Sartori  Sheila C. Stolf  Silvana B. Silva  Guilherme C. Lopes  Marcela Carrilho 《Journal of dentistry》2013

Objectives

The aim of this clinical study was to evaluate the long-term clinical performance of non-carious Class V restorations with and without application of chlorhexidine digluconate to acid-etched dentine.

Methods

After the approval of the Ethics and Informed Consent Committee, 70 non-carious cervical lesions were selected and randomly assigned into two groups, according to the split mouth design. The control group was restored with a two-step etch-and-rinse adhesive (Adper Single Bond 2) following manufacturer's instructions; whereas in the experimental group 2% chlorhexidine digluconate solution was applied to acid etched dentine for 30 s after etching and prior to the adhesive application. All lesions were restored with a nanofilled composite resin (Filtek Supreme XT) and polymerized with a light-curing unit operating at 600 mW/cm². Clinical performance was recorded after 1 week, 6, 12, and 36 months using modified Ryge/USPHS criteria in terms of retention, marginal discoloration, marginal integrity, post-operative sensitivity, and secondary caries incidence. Data were analyzed using Chi-Square, Fisher's exact test and McNemar tests (α = .05).

Results

After 36 months the control group showed a success rate of 88% in comparison to 76% of experimental group; however, no statistically difference between them was found (p = .463). Moreover, no statistical differences were observed between groups in the criteria post-operative sensitivity, marginal discoloration, marginal integrity, and secondary caries incidence between the two groups.

Conclusion

The addition of 2% chlorhexidine digluconate conditioning step does not improve the clinical durability of adhesive restorations.     

18.

Marginal leakage of Class II composite resin restorations: Part I     

Y Nakano  H Ohba  A Nitoh  T Hidaka  H Murasawa  M Takamizu  A Kohno 《Tsurumi shigaku》1987,13(3):335-342

     

19.

Marginal adaptation of class V composite restorations submitted to thermal and mechanical cycling     

Denise Sá Maia CASSELLI  André Luis FARIA-E-SILVA  Henrique CASSELLI  Luis Roberto Marcondes MARTINS 《Journal of applied oral science : revista FOB》2013,21(1):68-73

Objective:

This study evaluated the effect of the margin location and an adhesive system on the marginal adaptation of composite restorations.

Material and Methods:

Class V cavities were prepared in bovine teeth with the gingival margin on the dentin and the incisal margin on the enamel. The cavities were restored with a micro-hybrid composite resin using an etch-and-rinse [Single Bond 2 (SB)] or a self-etching adhesive [Clearfil SE Bond (CL)]. After finishing and polishing the restorations, epoxy replicas were prepared. The marginal adaptation was analyzed using scanning electronic microscopy (SEM, 500 x magnification). The higher gap width in each margin was recorded (T0). After the first evaluation, the samples were submitted to thermal cycling (2,000 cycles of 5ºC±2ºC followed by 55ºC±2ºC - T1) and mechanical cycling (100,000 cycles of 50 kN and 2 Hz - T2). Replicas of samples were rebuilt after each cycling and analyzed under SEM. The data were submitted to Mann-Whitney, Wilcoxon and Friedman testing (a=0.05).

Results:

The SB presented higher gaps in the dentin than the enamel, while there was no difference between the substrate for the CL. In the dentin, the CL showed better marginal sealing than the SB. The opposite occurred in the enamel. There were no significant differences between the baseline, thermal and mechanical cycling for any experimental condition.

Conclusions:

The outcomes of the present study showed that the adhesive system and margin location have an important effect on the marginal adaptation of composite restorations.     

20.

Two-year clinical performance of Class V resin-modified glass-lonomer and resin composite restorations     

Brackett WW  Dib A  Brackett MG  Reyes AA  Estrada BE 《Operative dentistry》2003,28(5):477-481

While a one-year report had been previously published, this study was undertaken to evaluate the clinical performance and appearance of a resin-modified glass ionomer and a resin composite over two years. Thirty-seven pairs of restorations of FujI II LC and Z 250/Single Bond were placed in caries-free cervical erosion/abfraction lesions without tooth preparation. Restorations were clinically evaluated at baseline, 6, 12, 18 and 24 months using modified Ryge/USPHS criteria. No statistically significant difference (p = 0.13) was observed in the overall performance of the materials. Retention was 96% for the resin-modified glass ionomer and 81% for the resin composite, with no additional restorations of either material lost after one year. As previously reported, retention of the Z 250 restorations at six months was below the minimum specified in the ADA Acceptance Program for Dentin and Enamel Adhesives. The resin composite restorations generally had a better appearance, with a 100% alpha rating in color match, versus 85% for the resin-modified glass ionomer.     

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.     

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提要：复合树脂直接修复技术在现阶段临床已广泛应用,有关其修复治疗后的临床疗效已有很多报道。本文介绍了有关复合树脂直接修复技术的临床疗效评估方法、标准及影响因素,为临床实际和疗效观察提供参考。     

两种充填方式对不同光固化复合树脂充填体内孔隙的影响

目的 探讨光固化复合树脂的稠度及充填方式对充填体内孔隙的影响,以期为复合树脂的临床应用提供参考.方法 6位操作者将3种复合树脂(树脂A:Prodigy;树脂B:Tetric EvoCeram;树脂C:Tetric Ceram HB)以器械充填和注射充填的方式充填入模拟I类洞中,将充填体纵向片切成0.5 mm厚的切片,测定切片内孔隙数量;并测试未进行充填的复合树脂内的固有孔隙数量.结果 未充填的复合树脂内固有孔隙数量极少(≤5个);稠度居中的树脂B的孔隙数量[器械充填和注射充填分别为(1137.1±365.0)和(566.1±206.4)个]远多于稠度最大的树脂C[分别为(193.1±35.8)和(156.3±33.0)个]和稠度最小的树脂A[分别为(241.0±116.1)和(195.8±28.7)个,P<0.05).树脂B器械充填的孔隙数量明显多于注射充填(P<0.05),而树脂A和C两种充填方式的孔隙数量差异均无统计学意义(P>0.05).结论 复合树脂充填体内的孔隙基本是在充填过程中形成的,孔隙数量与复合树脂稠度无线性关系;并非所有复合树脂用注射充填均能显著减少充填体内孔隙数量.     

A five-year clinical evaluation of Class II composite resin restorations

OBJECTIVES: To study the clinical efficacy of posterior composite resin restorations placed in general practice after five years. METHODS: Two commercial composite resin systems were used. Three general practitioners placed the restorations at a Public Dental Health Service Office. The patients were not selected specifically for this study. Class II cavities were restored with Superlux Molar and P-50 APC composite systems on an alternate basis. At baseline, 63 restorations were placed in molars and premolars in 45 patients. For primary caries, generally a conservative cavity design was used (n = 23), while replacements of amalgams resulted in the larger conventional Class II design (n = 40). The restorations were assessed using a modified USPHS criteria. Wear measurements were determined by the Leinfelder method. Photographs and bite-wing radiographs were taken to supplement the clinical evaluation of colour match, marginal adaptation and recurrent caries. Saliva sampling was performed to determine the rate of secretion and the level of mutans streptococci and lactobacilli. RESULTS: At the five-year review 51 restorations were available for examination, of which nine restorations were rated clinically unacceptable. Including the failed restorations (n = 7), at the three-year review, a total of 16 restorations had failed (27.6%) over a five-year period. The most common reasons for failure were recurrent caries (n = 7) and marginal defects (n = 4). The mean wear of Superlux Molar was 167 microns and of P-50 APC 158 microns. Eight of the 11 patients with failed restorations due to caries and marginal defects had high counts of mutans streptococci at baseline. CONCLUSIONS: The failures in the present group of patients did not specifically relate to material, tooth type or cavity design. However, it is suggested that patient factors such as caries activity should be monitored and managed.     

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.     

Influence of chlorhexidine digluconate on the clinical performance of adhesive restorations: A 3-year follow-up

Objectives

The aim of this clinical study was to evaluate the long-term clinical performance of non-carious Class V restorations with and without application of chlorhexidine digluconate to acid-etched dentine.

Methods

After the approval of the Ethics and Informed Consent Committee, 70 non-carious cervical lesions were selected and randomly assigned into two groups, according to the split mouth design. The control group was restored with a two-step etch-and-rinse adhesive (Adper Single Bond 2) following manufacturer's instructions; whereas in the experimental group 2% chlorhexidine digluconate solution was applied to acid etched dentine for 30 s after etching and prior to the adhesive application. All lesions were restored with a nanofilled composite resin (Filtek Supreme XT) and polymerized with a light-curing unit operating at 600 mW/cm². Clinical performance was recorded after 1 week, 6, 12, and 36 months using modified Ryge/USPHS criteria in terms of retention, marginal discoloration, marginal integrity, post-operative sensitivity, and secondary caries incidence. Data were analyzed using Chi-Square, Fisher's exact test and McNemar tests (α = .05).

Results

After 36 months the control group showed a success rate of 88% in comparison to 76% of experimental group; however, no statistically difference between them was found (p = .463). Moreover, no statistical differences were observed between groups in the criteria post-operative sensitivity, marginal discoloration, marginal integrity, and secondary caries incidence between the two groups.

Conclusion

The addition of 2% chlorhexidine digluconate conditioning step does not improve the clinical durability of adhesive restorations.     

Marginal adaptation of class V composite restorations submitted to thermal and mechanical cycling

Objective:

This study evaluated the effect of the margin location and an adhesive system on the marginal adaptation of composite restorations.

Material and Methods:

Class V cavities were prepared in bovine teeth with the gingival margin on the dentin and the incisal margin on the enamel. The cavities were restored with a micro-hybrid composite resin using an etch-and-rinse [Single Bond 2 (SB)] or a self-etching adhesive [Clearfil SE Bond (CL)]. After finishing and polishing the restorations, epoxy replicas were prepared. The marginal adaptation was analyzed using scanning electronic microscopy (SEM, 500 x magnification). The higher gap width in each margin was recorded (T0). After the first evaluation, the samples were submitted to thermal cycling (2,000 cycles of 5ºC±2ºC followed by 55ºC±2ºC - T1) and mechanical cycling (100,000 cycles of 50 kN and 2 Hz - T2). Replicas of samples were rebuilt after each cycling and analyzed under SEM. The data were submitted to Mann-Whitney, Wilcoxon and Friedman testing (a=0.05).

Results:

The SB presented higher gaps in the dentin than the enamel, while there was no difference between the substrate for the CL. In the dentin, the CL showed better marginal sealing than the SB. The opposite occurred in the enamel. There were no significant differences between the baseline, thermal and mechanical cycling for any experimental condition.

Conclusions:

The outcomes of the present study showed that the adhesive system and margin location have an important effect on the marginal adaptation of composite restorations.     

Two-year clinical performance of Class V resin-modified glass-lonomer and resin composite restorations

While a one-year report had been previously published, this study was undertaken to evaluate the clinical performance and appearance of a resin-modified glass ionomer and a resin composite over two years. Thirty-seven pairs of restorations of FujI II LC and Z 250/Single Bond were placed in caries-free cervical erosion/abfraction lesions without tooth preparation. Restorations were clinically evaluated at baseline, 6, 12, 18 and 24 months using modified Ryge/USPHS criteria. No statistically significant difference (p = 0.13) was observed in the overall performance of the materials. Retention was 96% for the resin-modified glass ionomer and 81% for the resin composite, with no additional restorations of either material lost after one year. As previously reported, retention of the Z 250 restorations at six months was below the minimum specified in the ADA Acceptance Program for Dentin and Enamel Adhesives. The resin composite restorations generally had a better appearance, with a 100% alpha rating in color match, versus 85% for the resin-modified glass ionomer.