复合树脂直接与间接修复后的牙体抗力实验研究

目的了解牙齿直接和间接用树脂修复后的牙体的抗力特性。方法40颗无龋前磨牙,制成MOD洞,然后分成4组,分别以Renew树脂直接充填,Renew直接嵌体修复,Tescera间接嵌体修复,制洞后不加修复。另以10颗完整前磨牙为对照。对上述所有牙齿采用力学模型静态力学加载实验,并进行对比分析研究。结果备洞未修复组牙齿的断裂载荷最小,与Renew树脂充填、Renew直接嵌体修复、Tescera间接嵌体修复及完整牙组有显著性差异(P<0.05);Renew树脂充填、Renew直接嵌体修复、Tescera间接嵌体修复和完整牙组之间抗断裂载荷无显著性差异(P>0.05)。在断裂模式上,Renew树脂充填组、Renew直接嵌体修复组和Tescera间接嵌体修复组分别出现9、3和1个样本树脂断裂。结论复合树脂充填和嵌体修复都能提高缺损牙齿的牙体抗力,复合树脂经过复合固化处理后力学性能有所提高。复合树脂不同固化处理对牙体抗力无明显影响。     

复合树脂充填不同角度楔形缺损效果的三维有限元分析

目的:研究复合树脂对下颌第一前磨牙4种角度楔形缺损的修复效果。方法:在前期建立的深1 mm,夹角分别为30°、60°、90°、120°的下颌第一前磨牙颊颈部楔形缺损有限元模型上,通过赋予牙本质参数和复合树脂参数,获得模拟复合树脂充填修复模型、模拟完整牙体实验模型和未修复的楔形缺损模型,分别经100 N轴向加载后,利用三维有限元分析法进行应力分析。结果:由牙本质充填模拟的完整牙体其应力分布状况与复合树脂充填体相似,均为近中侧高于远中侧,各种角度楔缺的Von Mises应力集中点均位于修复体外表面近中侧边缘;复合树脂修复体部分的Von Mises应力最大值低于模拟牙本质修复体。30°楔缺时树脂修复模型在平面O上承受较大应力的范围略大于完整牙体;在60°楔缺时树脂修复模型在平面O上承受较大应力的范围略小于完整牙体;在90°和120°楔缺时树脂修复模型在平面O上承受较大应力的范围明显小于完整牙体。30°、60°、90°、和120°4种楔形缺损角度情况下,树脂修复组和完整牙体组在直线L上的Von Mises应力分布接近(P>0.05),均明显小于未充填的楔缺模型(P<0.05)。结论:复合树脂充填对于4种夹角角度的楔形缺损均具有保护作用,可使患牙内部的应力分布情况恢复正常,更好的阻断了牙体内部的应力集中现象。     

不同大小MO洞型复合树脂嵌体修复应力分布的有限元分析

目的 探讨复合树脂嵌体修复后,近中邻（meiso-occlusal,MO）洞型面深度及宽度变化对牙体抗力的影响。方法采用锥形束CT（cone beam computed tomography,CBCT）扫描,结合Mimics、Geomagic Studio逆向工程等软件,建立不同大小邻（II类）MO洞型树脂嵌体修复的三维有限元模型,用ANSYS Workbench软件网格划分并求解分析各模型内部牙体及嵌体在垂直、舌向45°加载下主应力峰值及Von-mises应力分布情况。结果大小不同的MO洞型以复合树脂嵌体修复时,龈壁对应处是嵌体的主要应力所在,洞底部近髓腔处是牙体的主要应力集中区。随着面洞型深度、宽度增加,牙体、修复体的最大应力峰值及Von-mises应力集中区分布范围加大;牙体Von-mises应力受洞型宽度的影响更大,嵌体的Von-mises应力受洞型深度增加影响更大。侧向加载大大增加了牙体和修复体的应力峰值。结论MO洞型以树脂嵌体修复后,洞深、洞宽度加大及侧向加载增加了牙体与嵌体的应力峰值,改变了应力集中区分布范围。     

树脂嵌体冠修复无髓牙的临床研究

目的:比较树脂嵌体冠与口内直接树脂修复、瓷嵌体修复方法临床疗效的差别.方法:将符合纳入标准的94个患牙随机分为3组,分别以硬质树脂嵌体冠、复合树脂充填和瓷嵌体修复牙体外形.随访2年,观察比较3种修复体边缘密合情况、邻接恢复、牙周健康、术后牙体组织折裂率.结果:树脂嵌体冠组术后2年牙齿和修复体折断率为零.其边缘密合性、邻接恢复、牙周健康程度均明显优于树脂直接充填组(P<0.05),与全瓷嵌体相比无统计学筹异.结论:嵌体冠能精准地修复无髓牙的邻、(牙合)面外形,较复合树脂直接充填有助于患牙的牙周组织健康,降低无髓牙受力折裂的几率.     

两种方法修复老年患者磨牙牙体大面积缺损的对比性研究

目的:研究间接树脂嵌体修复和复合树脂直接充填磨牙大面积牙体缺损在老年患者中的临床疗效.方法:选择184例老年患者,将符合纳入标准的200颗患牙随机分为2组,分别以硬质树脂嵌体及复合树脂充填修复牙体外形.随访3年,参考美国公共健康会(USPHS)标准,对其临床效果进行观察.结果:2种方法在色泽匹配、边缘着色、龈指标、磨损程度及继发龋方面无统计学差异(P＞0.05);在邻接关系、边缘完整性及修复体折裂方面具有统计学意义(P＜0.05).结论:硬树脂嵌体修复比复合树脂充填能更好地恢复老年患者磨牙正常邻接关系,防止食物嵌塞,保持牙周组织健康.     

全瓷嵌体修复后牙牙体缺损166例疗效分析

目的:全瓷嵌体修复后牙牙体缺损166例,分析其临床疗效.方法:全瓷嵌体应用于后牙牙体缺损修复,并与复合树脂嵌体作对照,从边缘着色、边缘密合度、解剖形态、基牙继发龋、修复体折裂、颜色匹配等方面进行比较.结果:经过3年的临床观察,全瓷嵌体在边缘着色、基牙继发龋、解剖形态、颜色匹配等方面的临床疗效优于复合树脂嵌体.结论:全瓷嵌体是一种较好的新型牙体缺损修复体.     

Gradia微瓷聚合复合树脂嵌体修复牙体缺损的临床研究

目的：观察Gradia微瓷聚合复合树脂嵌体修复牙体缺损的临床疗效。方法：53例后牙牙体缺损病例采用Gradia微瓷聚合复合树脂嵌体进行修复共125件。分别于修复后2、6、12、24个月进行随访观察,评价修复体完整度、边缘适合度、外形及颜色匹配等。结果：随访125件修复体,均无继发龋发生,其中109例修复体完好,具有良好的边缘密合度,107例颜色匹配,5例修复体折裂,临床合格率87.2%。结论：Gradia微瓷聚合树脂嵌体能满足牙体缺损修复的临床要求。     

儿童后牙牙体大面积缺损的修复治疗

目的 :观察金属预成冠及复合树脂嵌体修复儿童后牙大面积缺损的临床效果。方法 :临床选择 4 7例后牙大面积缺损患儿 ,5 5颗牙齿 ,分别进行 3M金属预成冠修复和Colt埁ｎｅＢｒｉｌｌｉａｎｔ复合树脂嵌体修复 ,定期复查 ,评价治疗效果。结果 :经术后 12个月的临床观察 ,除一例嵌体修复脱落外 ,其余结果令人满意。结论 :在儿童大面积牙体缺损中 ,金属预成冠及复合树脂嵌体修复技术值得大力推广     

不同修复方法对深型楔状缺损牙应力分布影响研究

目的    应用三维有限元法分析不同修复方法对深型楔状缺损牙应力分布的影响。方法    选择上海市口腔病防治院门诊患者因正畸拔除的下颌第一前磨牙1颗作为研究样本,通过Micro-CT扫描并联合应用4种软件模拟重建下颌第一前磨牙深型楔状缺损模型,模型分别用复合树脂和瓷嵌体两种材料修复,洞形制备分为有倒凹和无倒凹两种方法。加载200 N垂直载荷后应用有限元分析软件进行应力分析。结果    牙颈部楔状缺损修复后其颈部牙体组织等效应力显著降低,其中采用全瓷嵌体修复缺损的模型颈部牙体组织等效应力降低最多。各模型修复体位移和颊尖位移均无明显差异。Ⅲ度楔状缺损各修复模型中,单纯采用树脂修复模型的修复体等效应力和最大应力均低于其他两种模型。Ⅳ度楔状缺损各修复模型中,采用全瓷嵌体修复模型的修复体等效应力和最大应力均显著低于其他两种模型,采用树脂修复的两个模型其修复体等效应力之间无明显差异。结论　修复治疗可缓解楔状缺损牙缺损区的牙体硬组织应力集中。Ⅲ度楔状缺损可采用树脂修复;Ⅳ度楔状缺损推荐优先选择全瓷嵌体修复,树脂修复则建议增加固位倒凹。     

儿童后牙牙体大面积缺损2种修复治疗的临床研究

目的：探讨儿童后牙牙体大面积缺损不同修复治疗的临床效果。方法：临床选择98例患儿后牙大面积缺损112颗患牙，随机分成实验组和对照组，作铸瓷嵌体修复或光固化复合树脂充填修复，并经1～2年临床疗效的追踪观察。结果：用铸瓷嵌体修复的病例成功率为80．5％，而采用树脂充填修复的成功率为56.8％。结论：在儿童大面积牙体缺损中，铸瓷嵌体修复技术有一定的临床应用价值可以推广，但制作中应注意适应证的选择，掌握操作要点，以提高成功率。     

Fracture resistance and microtensile bond strength of maxillary premolars restored with two resin composite inlay systems

PURPOSE: To compare the in vitro fracture resistance and the microtensile bond strength (muTBS) of premolar teeth restored with two light-cured resin composite inlay systems. METHODS: 50 sound human maxillary premolars were divided randomly into five equal groups. Four groups received mesial-occlusal-distal (MOD) inlay preparations. Restorative treatments comprised: Group 1 (Renew direct resin composite), Group 2 (Renew direct resin composite inlay), Group 3 (Tescera indirect resin composite inlay), Group 4 (non-restored), Group 5 (intact). All teeth were loaded axially until fracture. The same resin-based materials as used in Groups 1-3 were bonded to the superficial coronal dentin of 15 teeth. Beams approximately 1.0 mm x 1.0 mm were prepared and tested in microtensile mode. Results were compared using one-way ANOVA and Tukey's multiple comparison tests. RESULTS: Mean fracture strengths (KN): Group 1, 2.06 (0.76); Group 2, 2.30 (0.49); Group 3, 2.62 (0.68); Group 4, 1.24 (0.44); Group 5, 2.40 (0.71). Group 4 was significantly weaker that the other four groups, P < 0.01. Mean muTBSs (MPa): Group 1, 33.38 (6.24); Group 2, 20.38 (6.24); Group 3, 20.87 (4.62). Group 1 was significantly stronger than the other two groups, P < 0.01.     

Fracture resistance of class II preformed ceramic insert and direct composite resin restorations

Objectives. This study aimed to compare the fracture resistance of two different posterior restorations in class II cavities.Methods. In this study 24 extracted intact human mandibular molars (for testing) and 24 extracted intact human teeth (for achieving contact) were used. The test teeth were divided into two groups and then mounted in normal anatomic relationship with intact human teeth on the same holder. Thus 12 pairs of teeth were constituted in each group. Class II MO cavities were prepared on testing teeth in each holder. The other tooth was used for achieving contact. The cavities in group 1 were restored with direct composite resin with the manufacturer's flowable composite. The cavities in group 2 were restored with SONICSYS inlays (preformed ceramic insert) according to the manufacturer's instructions. The marginal ridges of the restorations were loaded at an angle of 13.5 degrees to the long axis of the tooth in an Instron testing machine until failure occurred.Results. Analysis of mean failure loads indicated that class II SONICSYS inlay restorations (group 2) had a significantly greater fracture resistance than did class II direct composite resin restorations with flowable composite (P=0.000).Conclusions. The SONICSYS inlay system provided greater fracture resistance than direct composite resin with flowable composite.     

Effect of restoration method on fracture resistance of endodontically treated maxillary premolars

PURPOSE: The aim of the present study was to compare the fracture resistance of endodontically treated maxillary premolars with mesio-occlusodistal (MOD) cavities restored using various restorative materials and luting agents. MATERIALS AND METHODS: Eighty extracted human maxillary premolars satisfying certain predetermined criteria were subjected to seven different restoration methods (10 premolars per method). After endodontic treatment, an MOD cavity was prepared in each specimen, and restoration was carried out by one of the following methods: group 1 = control (intact premolars); groups 2 and 3 = restoration using a photo-cure resin composite with and without bonding, respectively; groups 4 and 5 = restoration using a cast-metal inlay with zinc phosphate and adhesive resin cements, respectively; groups 6 and 7 = restoration using a cast-metal onlay with zinc phosphate and adhesive resin cements, respectively; and group 8 = restoration using a hybrid resin onlay. A fracture test was conducted to determine the fracture resistance and fracture mode of each specimen. RESULTS: Fracture resistance was greatest for teeth restored using a cast-metal onlay cemented with adhesive resin cement, but those fractures that did occur were generally unrestorable. Fracture resistance of teeth restored using a cast-metal inlay was also high. Fracture resistance for teeth restored using a resin composite was significantly lower, but the majority of these fractures were restorable. CONCLUSION: Endodontically treated maxillary premolars with MOD cavities could be successfully restored by cast onlay and inlay restorations luted with adhesive resin cement, but their failure mode was often unfavorable.     

The effect of different restoration techniques on the fracture resistance of endodontically-treated molars

AIM: This study compared the fracture resistance of endodontically-treated mandibular molars with mesio-occluso-distal (MOD) cavities restored using different restoration techniques. METHODOLOGY: Sixty sound extracted mandibular molars were randomly assigned to six groups (n=10). Group 1 did not receive any preparation. The teeth in Groups 2-6 received root canal treatment and a MOD cavity preparation. The teeth in Group 2 were kept unrestored. Group 3 was restored conventionally with amalgam. Group 4 was restored with a dentin bonding system (DBS, Clearfil SE Bond) and resin composite (CR) (Clearfil Photoposterior). Group 5 was restored with indirect hybrid ceramic inlay material (Estenia). In Group 6, polyethylene ribbon fiber (Ribbond) was inserted into cavities in a buccal-to-lingual direction and the teeth were then restored with DBS and CR. After finishing and polishing, the specimens, except for Group 2, were loaded to failure by a chewing simulation device (60,000 cycles x 50 N load, 1.3 Hz frequency) in an artificial environment at 37 degrees C. Each tooth was subjected to compressive loading perpendicular to the occlusal surface at a crosshead speed of 1 mm/minute. The mean loads necessary to fracture were recorded in Newtons and the results were statistically analyzed. RESULTS: The mean fracture values were as follows: Group 1: 2485.3 +/- 193.98a, Group 2: 533.9 +/- 59.4a, Group 3: 1705.8 +/- 135.7a, Group 4: 2033.3 +/- 137.6cd, Group 5: 2121.3 +/- 156.5d, Group 6: 1908.9 +/- 132.2cd. There were statistically significant differences between the groups annotated with different letters. Thus, Group 1 (intact teeth) had the greatest fracture resistance and Group 2 (non-restored teeth) the poorest. No statistically significant differences were found between Groups 3 (amalgam), 4 (resin composite) and 6 (polyethylene ribbon fiber reinforced composite) (p > 0.05). Group 5 (indirect hybrid ceramic inlay) had greater fracture resistance than Group 3 (p < 0.05). CONCLUSIONS: Within the limitations of this study, although all of the restoration groups were stronger than the prepared-only group, none of the restoration techniques tested was able to completely restore the fracture resistance lost from MOD cavity preparation. However, use of indirect hybrid inlay restorations in these teeth may be recommended, because this restoration technique indicated more favorable fracture failure modes than other restoration techniques used in this study and particularly greater fracture strength than amalgam restorations. The promising result of indirect hybrid inlay restorations may need to be confirmed by long-term clinical studies.     

Resistance to maxillary premolar fractures after restoration of class II preparations with resin composite or ceromer.

OBJECTIVE: The aim of this study was to evaluate the resistance to fracture of intact and restored human maxillary premolars. METHOD AND MATERIALS: Thirty noncarious human maxillary premolars, divided into three groups of 10, were submitted to mechanical tests to evaluate their resistance to fracture. Group 1 consisted of intact teeth. Teeth in group 2 received mesio-occlusodistal cavity preparations and were restored with direct resin composite restorations. Teeth in group 3 received mesio-occlusodistal cavity preparations and were restored with ceromer inlays placed with the indirect technique. After restoration, teeth were stored at 37 degrees C for 24 hours and then thermocycled for 500 cycles at temperatures of 5 degrees C and 55 degrees C. RESULTS: Statistical analysis revealed that group 3 (178.765 kgf) had a significantly greater maximum rupture load than did group 1 (120.040 kgf). There was no statistically significant difference between groups 1 and 2 or between groups 2 and 3. CONCLUSION: Class II cavity preparations restored with indirect ceromer inlays offered greater resistance to fracture than did intact teeth. The fracture resistance of teeth restored with resin composite was not significantly different from that of either the ceromer or intact teeth.     

Three-dimensional finite element analysis of strength and adhesion of composite resin versus ceramic inlays in molars

STATEMENT OF PROBLEM: Previous studies on strength of teeth reconstructed with ceramic or composite resin inlays have not resolved which restoration material provides the highest strength and marginal integrity. PURPOSE: The purpose of this study was to compare strength of mandibular molars restored with composite resin inlays to those restored with ceramic inlays, according to the Mohr-Coulomb failure criterion, and to analyze contact stresses in cement-tooth adhesive interfaces of these inlays. MATERIAL AND METHODS: The investigation used a 3-dimensional (3-D) finite element analysis with the use of contact elements. Seven 3-D models of first molars of the same shape and size were created: IT, intact tooth; UT, unrestored tooth with an MOD cavity preparation; CRIT, tooth restored with composite resin inlays (True Vitality) with an elastic modulus equal to 5.4 GPa; CRIH, tooth restored with composite resin inlays (Herculite XRV) (9.5 GPa); CRIC, tooth restored with composite resin inlays (Charisma) (14.5 GPa); CRIZ, tooth restored with composite resin inlays (Z100) (21 GPa); and CI, tooth restored with a ceramic (IPS Empress) inlay with an elastic modulus equal to 65 GPa. Each model was subjected to a force of 200 N directed to the occlusal surface. The stresses occurring in the tested inlays, composite resin cement layer, and tooth tissues were calculated. To evaluate the strength of materials, the Mohr-Coulomb failure criterion was used. Contact stresses in the cement-tissue adhesive interface were calculated and compared to tensile and shear bond strength of the luting cement to enamel and dentin. RESULTS: In the teeth restored with composite resin and ceramic inlays, the values of the Mohr-Coulomb failure criterion were lower than in the unrestored tooth with a preparation (UT), but still 2.5 times higher than in the intact tooth (IT). For the ceramic inlay (CI), the values of the Mohr-Coulomb failure criterion were nearly 3 times higher than in the composite resin inlays. For the luting agent for the ceramic inlay model, these values were 2-4 times lower than for the luting agents for the composite resin inlay models. At the adhesive interface between the cement and tooth around the ceramic inlays, contact tensile and shear stresses were lower than around the composite resin inlays. In the cervical enamel surrounding the proximal surface of the inlays, the stresses exceeded the tissue strength. CONCLUSIONS: Adhesively bonded composite resin and ceramic inlays reinforce the structure of prepared teeth, but do not restore their original strength. The proximal enamel surrounding inlays is prone to failure. The value of the Mohr-Coulomb failure criterion for ceramic inlays was higher than for composite resin inlays. With an increase in the elastic modulus of inlay materials, the values of the Mohr-Coulomb failure criterion decrease in the luting cement. Contact tensile and shear stresses on the cement-tissue adhesive interface decrease as well.     

Fracture resistance and stress distribution in endodontically treated maxillary premolars restored with composite resin.

PURPOSE: The aim of this study was to evaluate the effect of endodontic and restorative treatment on the fracture resistance of posterior teeth. MATERIALS AND METHODS: Fifty intact premolars were selected and randomly placed into five groups (n = 10): G1, intact teeth (control); G2, mesial-occlusal-distal (MOD) preparation; G3, MOD preparation restored with composite resin (Z-250, 3M ESPE); G4, MOD preparation and endodontic treatment; and G5, MOD preparation, endodontic treatment, and composite resin restoration. The specimens were submitted to an axial compression load in a mechanical test machine (EMIC), at a speed of 0.5 mm/min. Fracture patterns were analyzed at four levels. Five 2D numerical models were created by Ansys 10.0 for finite element analysis (FEA). RESULTS: Mean values of compressive strength for all groups were (Kgf): G1 (83.6 +/- 25.4); G2 (52.7 +/- 20.2); G3 (82.1 +/- 24.9); G4 (40.2 +/- 14.2); G5 (64.5 +/- 18.1). Statistical analysis (ANOVA and Tukey's test) showed that fracture resistance of G1 was significantly higher than that of G5, G2, and G4. Resistance of G3 was also higher than that of G2 and G4. Results showed that the tooth resistance is completely maintained when MOD preparation is restored with composite resin and partially recovered when MOD preparation associated with an endodontic access is restored in the same way. The endodontic treatment and composite resin restoration influenced stress distribution in the dental structure. CONCLUSIONS: Composite resin restoration plays an important role in recovering tooth strength. With regard to fracture mode, restoration and endodontic treatment increased the incidence of periodontal involvement, which was demonstrated by association with the finite element mechanical test method.     

In vitro comparison of cuspal fracture resistances of posterior teeth restored with various adhesive restorations

PURPOSE: This study compared the cuspal fracture resistances of posterior teeth restored with five different adhesive restorations. MATERIALS AND METHODS: Eighty-four sound human molars were included in this study. Sample molars were divided into seven groups. The first five groups received mesio-occlusodistal cavity preparations and were restored with (1) amalgam combined with urethane dimethacrylate cement, (2) posterior composite, (3) direct composite inlay, (4) cast-metal inlay, and (5) complete ceramic inlay. The sixth and seventh groups were introduced in the study as controls. Samples of group 6 were prepared but were tested without restoration (prepared-only group). Samples of group 7 were intact teeth and were tested as unprepared. All samples were loaded axially until failure. RESULTS: While the unprepared teeth had a significantly higher resistance than all other groups, the prepared-only teeth were the weakest. No significant differences were found in resistance to cuspal fracture among the restoration groups. CONCLUSION: The difference between the mean cuspal fracture resistance of the unprepared and prepared-only groups was statistically significant. Restoration groups were stronger than the prepared-only group. However, differences between the restoration groups were insignificant.     

Fracture resistance of thermal cycled and endodontically treated premolars with adhesive restorations

STATEMENT OF PROBLEM: Cavity preparations have routinely been associated with decreased fracture strength of restored teeth. PURPOSE: The purpose of this study was to evaluate the influence of endodontic treatment and thermal cycling on the fracture resistance of teeth restored with ceramic or composite resin inlay restorations. MATERIAL AND METHODS: One hundred sound, maxillary premolars were selected. Twenty intact teeth served as a control group. Eighty teeth were prepared with MOD cavity preparations; half of them were also endodontically treated. Inlay restorations were prepared with composite resin (Filtek Z250) or feldspathic ceramic (Vitadur Alpha). Half of the specimens for each group were submitted to thermal cycling (500 cycles, between 5 and 55 degrees C, dwell time of 30 seconds). The specimens were subjected to compressive axial loading using a steel ball. Data were analyzed using 3-way ANOVA and post hoc Tukey's test (alpha=.05). RESULTS: Except for those teeth restored with ceramic without endodontic treatment and thermal cycling, no other group achieved fracture strength similar to sound teeth. Ceramic and composite resin restorations provided similar resistance to fracture. There was a significant interaction between endodontic therapy and thermal cycling (P<.001). In the nonthermal cycled groups, endodontically treated teeth showed significantly lower fracture resistance (P<.001). All experimental groups had similar fracture strength when submitted to thermal cycling. CONCLUSIONS: Both restorative techniques provided similar fracture resistance. Endodontic treatment decreased the fracture resistance of nonthermal cycled specimens, while thermal cycling decreased the fracture resistance of nonendodontically treated specimens.     

Fracture resistance of endodontically treated teeth restored with indirect composite inlay and onlay restorations – An in vitro study

Objective

The purpose of this in vitro study was to evaluate and compare the fracture resistance and fracture mode of extensive indirect inlay and onlay composite resin restorations performed for endodontically treated premolars.

Materials and methods

A total of 55 extracted maxillary premolars were randomly divided into four groups. The first group (n = 15) remained untreated to serve as a positive control; the second group (n = 15) was endodontically treated with inlay cavities prepared and restored with indirect composite inlay restorations; the third group (n = 15) was also endodontically treated with onlay cavities prepared and restored with indirect composite onlay restorations; and the fourth group (n = 10) was endodontically treated with mesio-occlusodistal (MOD) cavities prepared and left unrestored to serve as negative controls. Dual cure indirect composite resin was used to fabricate the inlay and onlay restorations performed for the second and third groups, respectively. All teeth were subjected to compressive axial loading test using a metal ball (6 mm in diameter) in a universal testing machine (Instron 1195) with a cross-head speed of 0.5 mm/min until a fracture occurred. Statistical analysis of fracture resistance and fracture mode were performed with analysis of variance (ANOVA) (α = 0.05) and Kruskal–Wallis (α = 0.05) tests, respectively.

Results

For the four treatment groups, the mean fracture resistance values were 1326.9 N, 1500.1 N, 1006.1 N, and 702.7 N, respectively. Statistical analyses showed no significant differences between the mean fracture resistance of the intact tooth group and the inlay restoration group (p > 0.05), while significant differences were observed between the mean fracture resistance of all the other groups (p < 0.05). The Kruskal–Wallis test showed statistically significant differences between the fracture modes of the four groups.

Conclusion

Within the limitations of this study, endodontically treated teeth were successfully restored with indirect composite inlay and onlay restorations. However, the fractures that accompanied the inlay restorations were more severe and were unable to be restored.