No-Prep semidirect composite resin veneer. A Step-by-Step case report in a deciduous canine with a one-year follow-Up / Carilla de resina semidirecta sin preparación. Un reporte paso a paso en un canino deciduo con seguimiento de un año

Abstract The presence of deciduous canines in adulthood may be of aesthetic concern for patients. Many clinical alternatives include surgical and orthodontic treatment. Since patients search for highly esthetic results and more conservative alternatives, the present clinical report describes a treatment for deciduous canine through an indirect composite resin veneer and an indirect composite resin fragment restoration in a premolar to improve esthetic outcomes with a one-year follow up.

Resumen La presencia de caninos deciduos en adultos puede ser de preocupación estética por parte de los pacientes. Diversas alternativas clínicas pueden incluir tratamientos quirúrgicos y ortodóncicos. Desde que los pacientes buscan por resultados de alta estética y cada vez más conservadores, es que el presente caso clínico describe el tratamiento de un canino deciduo mediante una carilla indirecta de resina compuesta junto a un fragmento indirecto de resina de un premolar con el fin de mejorar los resultados estéticos, y con un año de seguimiento.

Influence of acid etching and universal adhesives on the bond strength to dentin

Abstract The purpose of this study was to evaluate the influence of the application mode of three universal adhesive systems on interfacial physical properties of indirect composite restorations adhesively cemented to dentin cavities. Seventy-eight bovine lower incisors were selected and a slice of dentin (thickness: 2 mm) between the buccal surface and pulp chamber was obtained for each tooth. Conical cavities were made on this surface. The internal walls of the cavities were then coated with a hydrophilic gel, filled with composite resin and photopolymerized. The dentin/cone sets were divided into 6 groups (n=10) according to type of universal adhesive (TETRI: Tetric N Bond, FUT: Futura Bond U, SBU: Single Bond Universal) and acid etching on dentin (A: with acid etching; WA: without acid etching). The acid etching and the adhesive systems were applied to the surface of the dentin. All composite resin cones were sandblasted (Al2O3, 20 s) and silanized. After surface treatment, the cones were cemented (RelyX Ultimate) into the dentin cavity and photopolymerized. After thermocycling (10,000 cycles), samples were submitted to marginal adaptation analysis (using caries detector dye), push-out test (0.5 mm/min), and failure mode analysis. Additional samples were prepared for nanoleakage analysis (SEM). The data (MPa) were analyzed by two-way ANOVA and Tukey's post-test (5%). The groups in which the dentin was acid etched showed significantly lower bond strength values in the push-out test (p<0.01). Dentin acid etching significantly reduced the bond strength between universal adhesive systems and dentin in indirect restorative procedures.

Resumo O objetivo deste estudo foi avaliar a influência do modo de aplicação de três sistemas adesivos universais nas propriedades físicas interfaciais de restaurações indiretas de compósito adesivamente cimentadas a cavidades dentinária. Setenta e oito incisivos inferiores bovinos foram selecionados e uma fatia de dentina (espessura: 2 mm) entre a face vestibular e a câmara pulpar foi obtida para cada dente. Cavidades cônicas foram feitas nesta superfície. As paredes internas das cavidades foram então revestidas com um gel hidrofílico, preenchidas com resina composta, e fotopolimerizados. Os conjuntos dentina/cone foram divididos em 6 grupos (n=10) de acordo com o tipo de adesivo universal (TETRI: Tetric N Bond, FUT: Futura Bond U, SBU: Single Bond Universal) e ácido na dentina (A: com condicionamento ácido; WA: sem condicionamento ácido). O condicionamento ácido e os sistemas adesivos foram aplicados na superfície da dentina. Todos os cones de resina composta foram jateados (Al2O3, 20 s) e silanizados. Após o tratamento superficial, os cones foram cimentados (RelyX Ultimate) na cavidade dentinária e fotopolimerizados. Após a termociclagem (10.000 ciclos), as amostras foram submetidas a análise de adaptação marginal (usando corante detector de carie), teste push-out (0,5 mm/min) e análise do modo de falha. Amostras adicionais foram preparadas para análise de nanoinfiltração (MEV). Os dados (MPa) foram analisados por ANOVA dois fatores e pós-teste de Tukey (5%). Os grupos em que a dentina foi condicionada por ácido apresentaram valores significativamente menores de resistência de união no teste push-out (p<0,01). O condicionamento ácido da dentina reduziu significativamente a resistência de união entre sistemas adesivos universais e dentina em procedimentos restauradores indiretos.

Microtensile bond strength of CAD/CAM-fabricated polymer-ceramics to different adhesive resin cements

OBJECTIVES: This study evaluated the microtensile bond strength (µTBS) of polymer-ceramic and indirect composite resin with 3 classes of resin cements. MATERIALS AND METHODS: Two computer-aided design/computer-aided manufacturing (CAD/CAM)-fabricated polymer-ceramics (Enamic [ENA; Vita] and Lava Ultimate [LAV; 3M ESPE]) and a laboratory indirect composite resin (Gradia [GRA; GC Corp.]) were equally divided into 6 groups (n = 18) with 3 classes of resin cements: Variolink N (VAR; Vivadent), RelyX U200 (RXU; 3M ESPE), and Panavia F2 (PAN; Kuraray). The μTBS values were compared between groups by 2-way analysis of variance and the post hoc Tamhane test (α = 0.05). RESULTS: Restorative materials and resin cements significantly influenced µTBS (p < 0.05). In the GRA group, the highest μTBS was found with RXU (27.40 ± 5.39 N) and the lowest with VAR (13.54 ± 6.04 N) (p < 0.05). Similar trends were observed in the ENA group. In the LAV group, the highest μTBS was observed with VAR (27.45 ± 5.84 N) and the lowest with PAN (10.67 ± 4.37 N) (p < 0.05). PAN had comparable results to those of ENA and GRA, whereas the μTBS values were significantly lower with LAV (p = 0.001). The highest bond strength of RXU was found with GRA (27.40 ± 5.39 N, p = 0.001). PAN showed the lowest µTBS with LAV (10.67 ± 4.37 N; p < 0.001). CONCLUSIONS: When applied according to the manufacturers' recommendations, the µTBS of polymer-ceramic CAD/CAM materials and indirect composites is influenced by the luting cements.

Comparison of shearbond strength between metal and indirect resin according to the different conditionings / 대한치과보철학회지

PURPOSE: The purpose of this study is to investigate the differences in bond strength of four different indirect composites to the gold alloy and Ni-Cr alloy according to type of metal surface treatment after water storage. MATERIALS AND METHODS: Type IV gold alloy and Ni-Cr alloy were used for casting alloy while four types of indirect composite resins (Gradia, Tescera Sinfony and in;joy) were used in this study. Metal specimens were produced by casting and total of 240 specimens (60 specimens per one indirect composite group) were prepared. After bonding indirect composite resin and undergoing 24 hours of polymerization, customized jig was attached to the metal specimen and shear bond strength were measured using universal testing machine. Also, differences in shear bond strength before and after water storage for 240 hours were also measured. RESULTS: In the measurement of shear bond strength according to the metal surface treatments, bead group showed high strength followed by loop and flatting group (P<.05). After being stored in water bath for 240 hours, Gradia showed statistically significant high bond strength compared to other indirect composite resins in all groups (P<.05). CONCLUSION: Shearbond strength was found to be different according to type of metal surface treatment and type of metal used after storage in water. Further studies need to be developed for clinical practices as three are still problems of microleakage, stain or wear.

Conservative Management Of Endodontically Treated Mandibular Molar By Indirect Composite: A Novel Approach.

Introduction: The patient’s desire for esthetics, coupled with the decreasing use of amalgam, requires that clinicians be comfortable and proficient in the use and placement of tooth-colored restoratives.Case Report: A 30 yrs old male came with chief complaint of large metallic filling on lower left back region came to the department for esthetic restoration. Patient had dental history of endodontic treatment with 36,37,46,47 and periodontal surgery with 46,47. Patient was advised by endodontic department for proper restoration of endodontically treated teeth to avoid fracture of treated tooth.Discussion: Indirect composite restorations demonstrate enhanced physical properties and predictable clinical performance having less polymerization shrinkage than direct composites. There is more strength in highly filled indirect composite. One of the most important attributes of indirect composite is the ability to create ideal contours and contacts with adjacent and opposing teeth that might be difficult to achieve clinically with large, directly placed composite restorations. [Kaushik ANJIRM 2016; 7(5):98-100]

The effect of various sandblasting conditions on surface changes of dental zirconia and shear bond strength between zirconia core and indirect composite resin

PURPOSE: To measure the surface loss of dental restorative zirconia and the short-term bond strength between an indirect composite resin (ICR) and zirconia ceramic after various sandblasting processes. MATERIALS AND METHODS: Three hundred zirconia bars were randomly divided into 25 groups according to the type of sandblasting performed with pressures of 0.1, 0.2, 0.4 and 0.6 MPa, sandblasting times of 7, 14 and 21 seconds, and alumina powder sizes of 50 and 110 microm. The control group did not receive sandblasting. The volume loss and height loss on zirconia surface after sandblasting and the shear bond strength (SBS) between the sandblasted zirconia and ICR after 24-h immersion were measured for each group using multivariate analysis of variance (ANOVA) and Least Significance Difference (LSD) test (alpha=.05). After sandblasting, the failure modes of the ICR/zirconia surfaces were observed using scanning electron microscopy. RESULTS: The volume loss and height loss were increased with higher sandblasting pressure and longer sandblasting treatment, but they decreased with larger powder size. SBS was significantly increased by increasing the sandblasting time from 7 seconds to 14 seconds and from 14 seconds to 21 seconds, as well as increasing the size of alumina powder from 50 microm to 110 microm. SBS was significantly increased from 0.1 MPa to 0.2 MPa according to the size of alumina powder. However, the SBSs were not significantly different with the sandblasting pressure of 0.2, 0.4 and 0.6 MPa. The possibilities of the combination of both adhesive failure and cohesive failure within the ICR were higher with the increases in bonding strength. CONCLUSION: Based on the findings of this study, sandblasting with alumina particles at 0.2 MPa, 21 seconds and the powder size of 110 microm is recommended for dental applications to improve the bonding between zirconia core and ICR.

Comparative study of the shear bond strength of various veneering materials on grade II commercially pure titanium

PURPOSE: To compare the shear bond strength of various veneering materials to grade II commercially pure titanium (CP-Ti). MATERIALS AND METHODS: Thirty specimens of CP-Ti disc with 9 mm diameter and 10 mm height were divided into three experimental groups. Each group was bonded to heat-polymerized acrylic resin (Lucitone 199), porcelain (Triceram), and indirect composite (Sinfony) with 7 mm diameter and 2 mm height. For the control group (n=10), Lucitone 199 were applied on type IV gold alloy castings. All samples were thermocycled for 5000 cycles in 5-55degrees C water. The maximum shear bond strength (MPa) was measured with a Universal Testing Machine. After the shear bond strength test, the failure mode was assessed with an optic microscope and a scanning electron microscope. Statistical analysis was carried out with a Kruskal-Wallis Test and Mann-Whitney Test. RESULTS: The mean shear bond strength and standard deviations for experimental groups were as follows: Ti-Lucitone 199 (12.11 +/- 4.44 MPa); Ti-Triceram (11.09 +/- 1.66 MPa); Ti-Sinfony (4.32 +/- 0.64 MPa). All of these experimental groups showed lower shear bond strength than the control group (16.14 +/- 1.89 MPa). However, there was no statistically significant difference between the Ti-Lucitone 199 group and the control group, and the Ti-Lucitone 199 group and the Ti-Triceram group. Most of the failure patterns in all experimental groups were adhesive failures. CONCLUSION: The shear bond strength of veneering materials such as heat-polymerized acrylic resin, porcelain, and indirect composite to CP-Ti was compatible to that of heatpolymerized acrylic resin to cast gold alloy.

Alternative anterior esthetics: A case report.

Due to the rise over the years in patient emphasis on better esthetic outcomes, veneering the metal base of a restoration with composite resin or porcelain is widely used in dentistry. For the preservation of the opposing natural dentition and the potential for repair, the use of composite veneering materials has been suggested because of their resilience, low abrasive properties, and superior repair potential. Composites are not as popular as porcelain, but they are still widely used to cover metal because of low cost and because the laboratorial procedures are faster and simpler.

In vitro cytotoxicity of indirect composite resins: Effect of storing in artificial saliva.

Aim: The aim of this study was to compare the cytotoxic effects of two indirect composite resins (Artglass and Solidex) on the viability of L-929 fibroblast cells at different incubation periods by storing them in artificial saliva (AS). Materials and Methods: Disk-shaped test samples were prepared according to manufacturers' instructions. Test materials were cured with light source (Dentacolor XS, Heraus Kulzer, Germany). The samples were divided into two groups. The first group's samples were transferred into a culture medium for 1 hour, 24 hours, 72 hours, 1 week and 2 weeks. The other group's samples were transferred into a culture medium for 1 hours, 24 hours, 72 hours, 1 week, and 2 weeks after being stored in AS for 48 hours. The eluates were obtained and pipetted for evaluation onto L-929 mouse fibroblast cultures incubated for 24 hours. Measurements were performed by MTT (3-(4,5)-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. The degree of cytotoxicity for each sample was determined according to the reference values represented by the cells with a control group. Results: Statistical significance was determined by ANOVA. Both groups presented lower cell viability in comparison to the control group at all periods. Storing in artificial saliva reduced cytotoxicity significantly (P < 0.05). Stored Artglass and Solidex showed similar effects on cytotoxicity. Nonstored Solidex samples were found more cytotoxic than Artglass samples. The cell survival rate results of 24-hour incubation period were significantly lower than those of the other experimental periods (P < 0.05). Conclusion: Storing indirect composite resins in AS may reduce cytotoxic effects on the fibroblast cells. However, resin-based dental materials continue to release sufficient components to cause cytotoxic effects in vitro after 48 hours of storing in AS.

Shear bond strength of a self-adhesive resin cement to resin-coated dentin / 대한치과보철학회지

PURPOSE: The aims of this study were to evaluate the effect of a resin coating on the shear bond strength of indirect composite restoration bonded to dentin with a self adhesive resin cement and to compare the shear bond strength with that of a conventional resin cement. MATERIALS AND METHODS: The occlusal enamels of thirty six extracted non-carious human molars were removed until the dentin flat surfaces of the teeth were exposed. Then, they were divided into 3 groups. The dentin surfaces of group 1 and 3 were left without any conditioning, while the dentin surfaces of group 2 were resin-coated with Clearfil SE bond and a flowable resin composite, Metafil Flo. After all specimens were temporized for 24 hours, indirect composite resin blocks fabricated by Tescera were bonded to dentins by Unicem for group 1 and 2, and by Panavia F for group 3. After 48 hours of water storage, shear bond strengths were measured. The data was analyzed with one-way analysis of variance and multiple comparison test (Tukey method). RESULTS: The shear bond strengths of Unicem applied to resin coated dentin surfaces were significantly higher than those of Unicem and Panavia F used to uncoated dentin surfaces (P<.0001). CONCLUSION: Application of a resin coating to the dentin surface significantly improved the shear bonding strength of a self adhesive resin cement in indirect restoration.

Effect of film thickness of resin cement on bonding efficiency in indirect composite restoration / 대한치과보존학회지

The purpose of this study was to evaluate the effect of film thickness of various resin cements on bonding efficiency in indirect composite restoration by measurement of microtensile bond strength, polymerization shrinkage, flexural strength and modulus, fractographic FE-SEM analysis. Experimental groups were divided according to film thickness ( 0.05). 3. Panavia F showed significantly lower polymerization shrinkage than other resin cements (p < 0.05). 4. Composite-based resin cements showed significantly higher flexural strength and modulus than adhesive-based resin cements (p < 0.05). 5. FE-SEM examination showed uniform adhesive layer and well developed resin tags in composite-based resin cements but unclear adhesive layer and poorly developed resin tags in adhesive-based resin cements. In debonded surface examination, composite-based resin cements showed mixed failures but adhesive-based resin cements showed adhesive failures.

Microtensile bond strength of self-etching and self-adhesive resin cements to dentin and indirect composite resin / 대한치과보존학회지

The purpose of this study was to evaluate the microtensile bond strength (microTBS), failure modes and bonding interfaces of self-etching and three self-adhesive resin cements to dentin and indirect composite resin. Cylindrical composite blocks (Tescera, Bisco Inc.) were luted with resin cements (PA: Panavia F 2.0, Kuraray Medical Inc., RE: RelyX Unicem Clicker, 3M ESPE., MA: Maxem, Kerr Co., BI: BisCem, Bisco Inc.) on the prepared occlusal dentin surfaces of 20 extracted molars. After storage in distilled water for 24 h, 1.0 mm x 1.0 mm composite-dentin beams were prepared. microTBS was tested at a cross-head speed of 0.5 mm/min. Data were analyzed with one-way ANOVA and Tukey's HSD test. Dentin sides of all fractured specimens and interfaces of resin cements-dentin or resin cements-composite were examined at FE-SEM (Field Emission-Scanning Electron Microscope). In conclusion, PA and RE showed higher bond strength and closer adaptation than MA and BI when indirect composite blocks were luted to dentin using a self-etching and three self-adhesive resin cements.

The study on the shear bond strength of resin and porcelain to Titanium / 대한치과보철학회지

STATEMENT OF PROBLEM: Recently, titanium has become popular as superstructure material in implant dentistry because titanium superstructure can be easily milled by means of computer-aided design and manufacture (CAD/CAM) technique. But retention form such as nail head or bead cannot be cut as a result of technical limitation of CAD/CAM milling and bond strength between titanium and porcelain is not as strong as that of conventional gold or metal alloy. PURPOSE: The objective of this study was to evaluate the shear bond strength of three different materials: heat curing resin, composite resin, porcelain which were bonded to grade II commercially pure Titanium (CP - Ti). MATERIAL AND METHODS: Thirty seven CP - Ti discs with 9 mm diameter, 10 mm height were divided into three groups and were bonded with heat curing resin (Lucitone 199), indirect composite resin (Sinfony), and porcelain (Triceram) which were mounted in a former with 7 mm diameter and 1 mm height. Samples were thermocycled for 1000 cycles at between 5 - 55 degrees C. Shear bond strength (MPa) was measured with Instron Universal Testing Machine with cross head speed of 1 mm/min. The failure pattern was observed at the fractured surface and divided into adhesive, cohesive, and combination failure. The data were analyzed by one-way ANOVA and Scheffe's multiple range test (alpha= 0.05). RESULTS: Lucitone 199 (17.82 +/- 5.13 MPa) showed the highest shear bond strength, followed by Triceram (12.97 +/- 2.11 MPa), and Sinfony (6.00 +/- 1.31 MPa). Most of the failure patterns in Lucitone 199 and Sinfony group were adhesive failure, whereas those in Triceram group were combination failure. CONCLUSION: Heat curing resin formed the strongest bond to titanium which is used as a CAD/CAM milling block. But the bond strength is still low compared with the bond utilizing mechanical interlocking and there are many adhesive failures which suggest that more studies to enhance bond strength are needed.

Analysis of the relationship between the surface hardness and Wear resistance of indirect composites used as veneer materials

This study evaluated the surface hardness and wear resistance of indirect composites (Artglass and Solidex) and the existence of a correlation between these properties. Twenty-four specimens (12 per material) were fabricated using a polytetrafluoroethylene matrix (5.0 mm in diameter; 7.0 mm high) following an incremental technique. Polymerization was done with a xenon stroboscopic light curing unit. After polishing, the specimens were stored in water at 37°C during either 1 day (n=6 per material) or 55 days (n=6 per material), after which Vickers surface hardness and wear resistance were assessed. Data were analyzed statistically by unpaired Student t-test, two-way ANOVA and Tukey's test. Surface hardness. Artglass had higher surface hardness than Solidex after 1-day immersion period (p<0.01), but after 55 days there was no significant difference between the materials (p>0.05). Comparing the materials at both periods, Artglass means differed significantly to each other (p<0.01), while no significant difference was found between Solidex means (p>0.05). Wear resistance. Solidex had higher wear than Artglass after 1-day immersion period (p<0.01), but no significant difference was found between the materials after 55 days (p>0.05). Comparing the materials at both periods, Artglass means differed significantly to each other (p<0.01), with higher wear at 55-day period, but no difference was found between Solidex means (p>0.05). These results suggest that Artglass was better than Solidex in terms of hardness and wear resistance after 1-day water immersion. However, it was more susceptible to degradation, showing greater wear after 55 days. In conclusion, there was an inverse correlation between surface hardness and wear resistance for both Artglass and Solidex indirect composites, that is the higher the hardness, the lower the wear.

Este trabalho avaliou a dureza superficial e resistência à abrasão de duas resinas compostas indiretas (Artglass e Solidex) bem como a existência de correlação entre estas propriedades. Foram confeccionados 24 corpos-de-prova (12 de cada compósito) pela técnica incremental utilizando uma matriz de politetrafluoretileno. A polimerização foi feita usando uma unidade fotopolimerizadora com lâmpada estroboscópica de xenônio. Após polimento, os corpos-de-prova foram armazenados em água a 37°C durante períodos de 1 dia (n=6 por material) ou 55 dias (n=6 por material), após os quais a dureza superficial Vickers e a resistência à abrasão foram testadas. Os dados foram analisados estatisticamente por meio do teste t de Student não-pareado, ANOVA a dois critérios de classificação e teste de Tukey. A comparação entre os materiais para a dureza superficial demonstrou que, no período de 1 dia, Artglass teve maior dureza (p<0,01). No período de 55 dias não houve diferença estatisticamente significante entre os materiais (p>0,05). Comparando os materiais nos dois períodos, Artglass apresentou diferença estatisticamente significante (p<0,01), o que não foi observado para o Solidex (p>0,05). A comparação entre os materiais para a resistência à abrasão demonstrou que, no período de 1 dia, o Solidex teve maior desgaste (p<0,01) que o Artglass, enquanto no período de 55 dias não houve diferença significante (p>0,05). Comparando os materiais em ambos os períodos, houve diferença estatisticamente significante para o Artglass (p<0,01), com maior desgaste no período de 55 dias, mas não houve diferença significante para o Solidex (p>0,05). Esses resultados sugerem que o Artglass teve melhor desempenho que o Solidex quanto à dureza e resistência ao desgaste após 1 dia de imersão em água; porém, foi mais suscetível à degradação, com maior desgaste após 55 dias. Concluiu-se que houve correlação inversa entre dureza superficial e resistência ao desgaste para os compósitos...

The effect of bonding resin on bond strength of dual-cure resin cements / 대한치과보존학회지

The objective of this study is to evaluate the effect of an additional application of bonding resin on the bond strength of resin luting cements in both the light-cure (LC) and self-cure (SC) modes by means of the microTBS tests. Three combinations of One-Step Plus with Choice, Single Bond with Rely X ARC, and One-Up Bond F with Bistite II were used. D/E resin and Pre-Bond resin were used for the additional application. Twelve experimental groups were made. Three mandibular 3rd molars were used in each group. Indirect composite blocks were cemented on the tooth surface. 1 x 1 mm2 dentin-composite beam for microTBS testing were made and tested. When total-etching dentin adhesives were used, an additional application of the bonding resin increased the bond strength (P 0.05). In conclusion, the results suggest that an additional application of the bonding resin increases bond strength and enhances quality of bonding when using total-etching dentin adhesives.

An in-vitro wear study of indirect composite resins against human enamel / 대한치과보철학회지

STATEMENT OF PROBLEM: Second-generation indirect composite resins have been improved flexural strength, compressive strength, hydrolytic degradation resistance, wear resistance compared to first-generation indirect composite resins, but there are still some problems as hydrolysis and low wear resistance. Some manufacturers claim that wear resistance of their materials has been improved, but little independent study has been published on wear properties of these materials and the properties specified in the advertising materials are largely derived from in-house or contracted testing. PURPOSE: This study was to evaluate the wear of indirect composite resins (SR Adoro, Sinfony, Tescera ATL) and gold alloy against the human enamel. MATERIAL AND METHOD: Extracted human incisors and premolars were sectioned to 2*2*2mm cube and embedded in the clear resin and formed conical shaped antagonist to fit the jig of pinon-disk tribometer. Total 20 antagonists were stored in distilled water. Five disk samples, 24mm in diameter and 1.5mm thick, were made for each of three groups of indirect composite resins and gold alloy group, and polished to #2,000 SiC paper on auto-polishing machine. Disk specimens were tested for wear against enamel antagonists. Wear test were conducted in distilled water using a pin-on-disk tribometer under condition (sliding speed 200rpm, contact load 24N, sliding distance 160m). The wear of the enamel was determined by weighing the enamel antagonist before and after test, and the weight was converted to volumes by average density. The wear tracks were analyzed by scanning electron microscopy and surface profilometer to elucidate the wear mechanisms. Statistical analysis of the enamel wear volume, wear track depth and wear tract width of disk specimens were accomplished with one-way ANOVA and the means were compared for significant differences with Scheffe's test. RESULTS: 1. The enamel wear was most in gold alloy, but there were no statistically significant differences among all the groups (P>.05). 2. In indirect composite resin groups, the group to make the most shallow depth of wear tract was Sinfony, followed by Tescera ATL, SR Adoro (P.05). 3. The width of wear tract of SR Adoro was larger than the other groups (P.05). 4. SEM analysis revealed that Sinfony and gold alloy showed less wear scars after test, Tescera ATL showed more wear scars and SR Adoro showed the most. CONCLUSION: Within the limits of this study, Sinfony and gold alloy showed the least wear rates and showed similar wear patterns.

Tooth fracture resistance study after composite resin inlay by three dimensional finite element analysis / 实用口腔医学杂志

Objective: To evaluate fracture resistance of teeth restored with inlay restorations of direct and indirect composite resin. Methods:Three dimensional finite element analysis (3D FEA) was used in present research. Two types of load were applied to investigate the change of tooth fracture resistance after restored with MOD inlay. Group 1,2,3,and 4 were restored with four kinds of materials:group 1,indirect composite resin inlay( Tescera, Bisco USA);group 2, direct composite inlay(Renew Bisco USA);group 3,ceramic; and group 4, Co-Cr alloy. Defect tooth or intact one was served as the control group. Results:Tooth fracture resistance in group 1,2,3 and 4 were improved, Fracture resistance in group 1 and 2 were similar to intact tooth group, while the fracture resistance in group 3 and 4 was different effect when compared to intact tooth. Conclusion: Both direct and indirect composite resin inlay could strengthen fracture resistance of restored teeth. No obvious difference between direct and indirect composite resin on tooth resistance was found.