3-Year clinical evaluation of posterior packable composite resin restorations

This study evaluated the clinical performance of four packable resin composite restorative materials in posterior teeth (Class I and II) compared with one hybrid composite after 3 years. Eighty-four restorations were placed in 16 patients. The tested materials were: (i) Solitaire + Solid Bond; (ii) ALERT + Bond-1; (iii) Surefil + Prime & Bond NT; (iv) Filtek P60 + Single Bond and (v) TPH Spectrum + Prime & Bond 2.1. All restorations were made using rubber dam isolation, and the cavity design was restricted to the elimination of carious tissue. Deeper cavities were covered with calcium hydroxide and/or glass-ionomer cement. Each adhesive system and composite resin was placed according to the manufacturer's instructions. One week later, the restorations were finished/polished and evaluated according USPHS modified criteria. Fourteen patients attended the 3-year recall and 75 restorations were evaluated at that time based on the same evaluation criteria. Friedman repeated measures analysis of variance by rank and Wilcoxon sign-ranked test for pair-wise comparison was used for data analysis (alpha = 0.05). The analysis was performed only for the baseline and for the 3-year period. Solitaire showed some fractures at marginal ridges in 25% of the cases. Solitaire and ALERT showed some concerns related to colour match (43 and 77%, respectively) and surface texture (86 and 77%, respectively). TPH Spectrum showed a great percentage of colour mismatch after 3 years, around 50%. Surefil and Filtek P60 showed an excellent clinical performance after 3 years, similar to the hybrid resin tested, TPH Spectrum. Solitaire did not fulfil the ADA acceptance criteria for restorative materials and, therefore, is not recommended for use in posterior restorations.     

Direct posterior composite resin restorations: A review. 2. Clinical technique

Despite the increased use of composite resin to restore posterior teeth, there is evidence that clinicians should be selective in their use of these restorations. This paper describes the clinical technique--preparatory procedures, preparation of the cavity, preparation for placement of composite resin, placement of composite resin and finishing of the restoration--for the relatively conservative use of composite resin in posterior teeth and reviews the literature to discuss briefly many of the controversial aspects of the technique.     

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.     

A clinical evaluation of posterior composite restorations: 17-year findings

OBJECTIVE: Since an increasing number of composite restorations in posterior teeth are placed as a routine, this study was conducted to evaluate long-term survival of these restorations placed in general practice. METHODS: Patients from a private dental office that received restorations in posterior teeth between 1987 and 1988 with P-50 (3M) or Herculite XR (Kerr) resin composites were selected and invited to participate. Restorations were placed under rubber dam isolation. Dentine walls were covered with glass ionomer cement, and composites were placed according to manufacturer's instructions. Thirty-eight patients agreed to participate and signed an informed consent prior to the evaluation. Two calibrated operators worked independently in the evaluation, using modified USPHS criteria. Survival of restorations or subsets of restorations grouped on the basis of variables (material, tooth, cavity type and size) was determined using Kaplan-Meier survival curves. RESULTS: Ninety-eight failures were recorded among the 282 restorations providing a crude estimate of 34.8% failures. The survival rate was not significant for material (p=0.92) but was significant between tooth (lower premolars and lower molars, p<0.0001), cavity type (p<0.001) and size (p<0.001). The majority of restorations exhibited A or B scores for the evaluated criteria. The main failure cause was fracture of both composites. CONCLUSIONS: The clinical performance of posterior resin composite restorations evaluated was acceptable after 17-year evaluation. However, the probability of failure of resin composite restorations in molars, Class II, and large restorations is higher.     

自酸蚀粘接剂复合树脂修复后牙Ⅰ类洞三年的临床评价

目的评价自酸蚀粘接剂复合树脂修复后牙Ⅰ类洞的临床效果。方法70例中深龋磨牙分为两组,实验组36例采用自酸蚀粘接剂＋混合填料复合树脂修复,对照组34例使用全酸蚀牙本质粘接剂＋可充压复合树脂修复。结果在复查的三年期限内,两组修复体在术后敏感性、修复体表面形态、边缘密合性及继发龋方面均无显著性差异,色彩匹配性在术后一年和二年的统计学结果有显著性差异（P〈0.05）。结论用自酸蚀粘接剂和复合树脂修复后牙Ⅰ类洞可获得同样满意的临床效果,但混合填料复合树脂组色彩稳定性较可充压复合树脂组略差。     

Clinical performance of posterior resin composite restorations after up to 33 years

ObjectivesThis retrospective study evaluated the performance of posterior composites after up to 33 years of clinical service and investigated factors associated with the risk of failures over time including patient- and tooth-related variables.MethodsPatients who received at least one Class I or Class II direct composite restoration in a private office in 1986–1992 and had follow-up appointments were included. Failures and interventions over time were investigated using the dental records. A follow-up clinical recall was carried out in 2020. Two scenarios were considered: restorations that did not require any intervention (success) or restorations that were repaired and still functional (survival). Multivariate Cox regression analyses and Kaplan-Meier curves were performed using success and survival rates (p < 0.05).ResultsOne hundred patient records and 683 restorations were included. A total of 353 failures were reported (success rate= 48%). Main reasons for failure were fracture and secondary caries. Most interventions after failures were repairs. Replacements were registered in 183 cases (survival rate= 73%). Annual failure rates were below 2.5% (success) and 1.1% (survival). Larger restorations and maxillary molars had higher failure risks. No significant differences in success rates among different resin composites was observed. A typical observation in this sample of restorations was the presence of moderate to advanced signs of aging, including marginal and surface staining, wear, chipping, changes in anatomical shape and translucency. Clearly aged restorations were still clinically satisfactory. Significance: This long-term, practice-based study indicates that resin composites can be used to restore posterior teeth with a long-lasting durability.     

In vivo comparison of a microfilled and a hybrid minifilled composite resin in class III restorations: 2-year follow-up

An in vivo comparison was made of two different types of restorative resins over a 2-year period: a microfilled resin ( -1158262462Silux Plus, 3M-1158262462, USA) and a hybrid minifilled composite resin (-1158262461Herculite XRV, Kerr-1158262461, USA); 56 restorations were placed in 28 patients by one experienced dentist and examined by two independent evaluators using the United States Public Health Service (UPSHS) rating system for marginal adaptation, marginal discoloration, surface roughness, anatomic form and modified criteria for color match (direct and indirect evaluation). Modified criteria divided the classic A score into A1 for ”not detectable” filling and A2 for ”slightly discernible filling”. Restorations were evaluated at baseline, 1 week, 6 months, 1 year and 2 years later. After 2 years, all materials were considered satisfactory for marginal adaptation, anatomic form and surface roughness (no ”Charlie”, or ”Delta” ratings). No recurrent caries was observed. Clinical evaluation showed a significantly higher rate of marginal discoloration for the microfilled composite resin than the other resin. Hybrid composite resin materials may be expected to perform well as an anterior restorative material. Photographic ratings confirmed the clinical evaluation. The modified evaluation for color match demonstrated differences, which are not discernible with the USPHS system and showed, more rapidly, differences that appear later with the USPHS system. Received: 18 September 1998 / Accepted: 23 April 1999     

后牙病理性磨损树脂修复的临床效果探讨

目的:观察用直接树脂充填法和间接树脂充填法修复后牙病理性磨损的临床效果。方法:选择后牙牙合面有病理性磨损且具有充填空间的患者48例,患牙144颗,其中有牙本质过敏症状者38例98颗牙。患者按门诊顺序随机分为直接法修复组和间接法修复组2组各24例,在不备洞的情况下分别采用可乐丽菲露复合树脂直接或间接修复,比较治疗3个月及1年后树脂充填的临床效果、牙本质敏感情况和咀嚼效率改变情况。结果:治疗后3个月时复查,直接法和间接法两组患牙树脂充填体A级率无显著性差异(卡方检验,P>0.05);治疗1年后复查,间接法组患牙树脂充填体A级率优于直接法组,两组差异有统计学意义(卡方检验,P<0.05)。间接法组牙本质敏感治疗总有效率优于直接法组,两组差异有统计学意义(卡方检验,P<0.05)。治疗3个月及治疗1年后,间接法组的咀嚼效率高于直接法,两组差异有统计学意义(t检验,P<0.01)。结论:间接树脂法比直接树脂充填法修复后牙病理性磨损有较好的临床效果。     

Micromorphological evaluation of posterior composite restorations - a 10-year report

The summarized scanning electron microscopic-supported micromorphologic data of a 10-year longitudinal clinical study of GIC/Hybrid composite posterior restorations is reported. The aim of this study was to compare the results to USPHS-compatible clinical criteria of the CPM index and to analyse the deterioration pattern and the success rate. Out of a total of 194 Class I and Class II fillings 46 restorations were at baseline, after 1, 3, 5, 7 and 10 years. The restorations were micromorphologically examined using gold-sputtered replicas and coded according to the M-criteria of the CPM index. The features for surface roughness, surface texture, marginal integrity, excess of material, marginal fracture, loss of material, marginal leakage and other filling imperfections were assessed. Eighteen fillings showed perfect margins, rapidly deteriorating after the first year of service. Despite poor micromorphologic marginal conditions all restorations retained optimal functional characteristics. Parallel longitudinal micromorphologic and clinical assessment of posterior GIC/Composite restorations revealed fine structure and deterioration patterns of the tooth-biomaterial interface. The layer-technique using GIC as dentine replacement and resin-based composite as enamel replacement results, according to previous biocompatibility testing, and clinical data, in optimal pulp protection and correct anatomic form over a 10-year period. The myth of the need for perfect marginal integrity requires further discussion.     

Two-year evaluation of Class II resin-modified glass ionomer cement/composite open sandwich and composite restorations

Restorations made of a combination of resin modified glass ionomer cement (RMGIC) and composite resin (CR) – open sandwich fillings – have been recommended for use in proximal boxes of molar cavities. The aim of this study was to compare the clinical behaviour over time of RMGIC/CR sandwich restorations versus CR restorations in Class II molar cavities. During a period of 2 years, a total of 220 restorations were placed in 118 patients by one operator (VV). A random block allocation was used to allocate cavities to one of the two restorative techniques. Bitewing radiographs and photographs were taken at baseline and at annual recall appointments. At present, a total of 210 restorations have been evaluated after 1 year and 141 restorations after 2 years. All restorations were evaluated using a modification of USPHS criteria. A total of three RMGIC/CR and two CR restorations (2.8%) were rated as failures caused by endodontic complications or major fractures. Twenty-eight teeth were reported to have postoperative sensitivity at the baseline evaluation 1 week following placement. Nine RMGIC/CR (8.5%) and four CR (4.9%) restorations with minor fractures were rated Charlie but were still acceptable. Bitewing radiographs revealed progression of carious lesions in proximal surfaces of originally intact or restored teeth adjacent to five (5.9%) RMGIC/CR restorations and eight (10.9%) CR restorations. No statistically significant differences between the two types of restoration were observed with respect to marginal adaptation, discoloration and caries progression. However, a higher number of large CR fillings exhibited postoperative sensitivity at baseline compared to moderate CR or extensive and moderate RMGIC/CR restorations. Received: 28. January 2000 / Accepted: 8 May 2000     

A 2-year clinical study of composite and ceramic inlays

Objective long-term clinical data are necessary to evaluate the performance of dental restorations. This prospective clinical trial evaluated composite and ceramic inlays for clinical acceptability as restorative materials in posterior teeth and provided 2-year results. The study involved 7 student operators placing 47 composite inlays (Tetric, blend-a-lux, Pertac) and 24 ceramic inlays (Empress) under the supervision of an experienced dentist. Clinical assessment of 56 inlays (78.9%) was performed after 2 years with modified USPHS criteria and statistically analyzed using the Mann-Whitney U test and Fisher’s exact test. All the ceramic inlays and 90% of the composite inlays were considered clinically excellent or acceptable. During the first year 3 composite inlays failed and during the second evaluation period 1 had to be replaced. Ceramic inlays produced significantly better ”anatomic form of the surface” (P=0.038) and ”integrity of the restoration” values (P=0.043). Inlays in small cavities exhibited superior ”marginal integrity” (P=0.026) and ”marginal discoloration” values (P=0.034). Fisher’s test revealed a significantly higher failure rate in molars than in bicuspids (P=0.034). Posterior tooth- colored inlays exhibited a success rate of 100% for ceramic inlays and 90% for composite inlays even if placed by relatively inexperienced but supervised student operators. Received: 4 June 2000 / Accepted: 3 August 2000     

A 4-year clinical study on amalgam, resin composite and resin-modified glass ionomer cement restorations in overdenture abutments

Objective: To assess the performance of three different filling materials in overdenture abutment teeth.

Methods: In 49 patients amalgam, resin composite and resin-modified glass ionomer cement were used to seal the root canal orifices of 155 overdenture abutment teeth. After initial preparation of the cavities, the three restorative materials were randomly assigned to the abutment teeth using a number of balancing criteria. All patients were reviewed every six months and received the same preventive regimen. Survival was assessed at two levels: S_orig (survival of the restoration independent from eventual maintenance treatments) and S_comp (restorations survived even without maintenance treatments).

Results: The calculated overall survival percentage of the original restorations (S_orig) after four years was 63±6% (mean±SE). Calculation for the overall complete survival (S_comp) revealed a percentage survival of 57±6%. At both levels, the differences between the survivals of the investigated materials were not statistically significant (p-values>0.05). Two abutments were lost, severe caries was the reason for one extraction and another abutment tooth was extracted for periodontal reasons.

Conclusions: The results of this study did not point out a superior restorative material for the seal of root canal orifices of overdenture abutments. The distribution of failures over the patients indicates a certain patient dependency.     

Internal adaptation and overhang formation of direct class II resin composite restorations

The aim of the present in vitro study was to evaluate different restorative concepts for posterior resin composite fillings in terms of internal adaptation and overhang formation. Eighty standard occluso-distal cavities with and without a 1.5-mm bevel were restored in a phantom head using Syntac Classic and Tetric Ceram with and without Tetric Flow as thin lining or Solid Bond and Solitaire with and without FlowLine. The restorations were finished intraorally and afterwards subjected to thermal loading (1150× +5°C/+55°C) for 24 h. The proximal margins of the original specimens were analyzed for overhangs under a stereo light microscope (100-fold magnification) before and after intraoral control with loupes, including additional polish. Afterwards the teeth were cut longitudinally, replicated, and their internal integrity analyzed under a SEM (200-fold magnification). The combination of flowable and viscous composites resulted in enhanced internal adaptation for both adhesive systems. However, Syntac Classic exhibited superior adaptation characteristics compared with Solid Bond. In terms of overhang formation, the use of flowable materials always led to higher percentages of marginal overhangs in beveled cavities. Higher viscous materials alone resulted in higher percentages of underfilled margins of beveled than box-shaped cavities. It was clear that the use of magnifying glasses during finishing was beneficial for reducing marginal overhangs up to 40%. Received: 24 June 1999 / Accepted: 24 August 1999     

Durability of resin composite restorations in high C-factor cavities: A 12-year follow-up

Objective

Polymerization shrinkage and shrinkage stress has been considered as one of the main disadvantages of resin composite restorations. Cavities with high C-factors increase the risk for interfacial failures. Several restorative techniques have been suggested to decrease the shrinkage stress. The purpose of this study was to evaluate the durability of techniques as oblique layering, indirect curing and/or a laminate with a poly-acid modified resin composite in direct Class I resin composite restorations in a 12-year follow-up.

Methods

Each of 29 patients received one or two pair(s) rather extensive Class I restorations. The first restoration was a poly-acid modified resin composite/resin composite sandwich restoration and the second a direct resin composite restoration. Both restorations, except for the laminate layer, were placed with oblique layering and two-step curing technique. 90 restorations were evaluated annually with slightly modified USPHS criteria during 12 years.

Results

At 12 years, 38 pairs were evaluated. Two cases of slight post-operative sensitivity were observed in one patient. A cumulative failure rate of 2.4% was observed for both the resin composite and the laminate restorations. One laminate restoration showed non-acceptable color match, but was not replaced and one resin composite restoration showed a chip fracture. Five restorations were replaced due to primary proximal caries.

Conclusions

The high failure rate expected in the high C-factor Class I cavity, associated with polymerization shrinkage and shrinkage stress, were not observed. The techniques used resulted in an excellent durability for the Class I resin composite restorations.     

Two-year clinical performance of a nanofiller vs a fine-particle hybrid resin composite

The aim of the study was to evaluate the clinical performance of the nanofiller resin composite Filtek Supreme (3M ESPE) vs the conventional fine hybrid resin composite Tetric Ceram (Ivoclar Vivadent) in stress-bearing posterior cavities. In accordance with a split mouth study design, 50 patients (35.7±11.3 years) received at least one pair of Filtek Supreme and Tetric Ceram restorations in each of two comparable class II cavities. To obtain comparability, the adhesive Scotchbond 1 was used for all the restorations. After 2 years, the restorations (total number 112) were scored according to the Ryge criteria. After 2 years (recall rate 100%), the results (%) of the Ryge evaluation for the two groups Filtek Supreme/Tetric Ceram were marginal adaptation: Alfa 96/96, Bravo 2/2, Charlie 2/0, and Delta 0/2; anatomic form: Alfa 98/98, Bravo 0/0, and Charlie 2/2; secondary caries: Alfa 100/100 and Bravo 0/0; marginal discoloration: Alfa 98/100, Bravo 2/0, and Charlie 0/0; surface: Romeo 95/95, Sierra 4/4, Tango 0/0, and Victor 2/2; and color match: Oscar 46/57, Alfa 50/39, Bravo 2/4, and Charlie 2/0. One Tetric Ceram and one Filtek Supreme restoration showed fractures that needed restorative intervention. No severe postoperative sensitivities were reported within the observation period. All restored teeth remained vital; the integrity of all the teeth was scored Alfa. After 2 years, no statistically significant differences (Wilcoxon–Mann–Whitney test) was found between the two restorative materials investigated. Therefore, Filtek Supreme, based on a new nanofiller technology, has proved efficaciousness for clinical use in stress-bearing posterior cavities.     

Eighteen‐month clinical evaluation of microhybrid,packable and nanofilled resin composites in Class I restorations

Summary The aim of this article was to report the results of an 18‐month longitudinal randomized clinical trial that evaluated the clinical performance of microhybrid, packable and nanofilled resin composite restorations placed in Class I cavities of molar teeth. Three Class I resin composite restorations were placed in each of 35 patients. Each patient received one microhybrid (‘Point 4’; Kerr, Orange, CA, USA), one packable (‘Packable Premise’; Kerr, Orange, CA, USA) and one nanofilled (‘Nanofilled Premise’; Kerr, Orange, CA, USA) resin composite restoration. Clinical evaluation was performed at baseline (2 weeks after placement), and after 6, 12 and 18 months after placement using modified Ryge criteria. No patients were lost from the study. At the final appointment (after 18 months), 95·4%, 93·7% and 96·2% respectively of the microhybrid (‘Point 4’), packable (‘Packable Premise’ and nanofilled (‘Nanofilled Premise’) resin composite restorations received Alfa ratings. Regardless of the type of restorative material, no significant changes were observed in the modified Ryge criteria at the baseline and 18‐month recalls (P ≤0·05). Three restorations (one from each group) exhibited post‐operative sensitivity at the baseline and 6‐month appointment. After 18 months, one packable resin composite restoration failed because of secondary caries, while secondary caries was not detected on any of the other restorations. The clinical performance of microhybrid (‘Point 4’), packable (‘Packable Premise’) and nanofilled (‘Nanofilled Premise’) resin composite restorations was acceptable after 18 months. Further studies with longer follow‐up periods are recommended to investigate the long‐term survival of these restorations.     

Pilot study of unidirectional E-glass fibre-reinforced composite resin splints: up to 4.5-year clinical follow-up

Objectives

This prospective clinical pilot study evaluated the performance of fibre-reinforced-composite resin (FRC) splints on mandibular anterior teeth.

Methods

Between June-2003 and January-2008, 19 patients (7 females, 12 males, 45-72 years old) from a group of consecutive patients who completed periodontal therapy received E-glass FRC splints (everStick Perio, StickTech) in combination with two types of flowable and restorative resin-composites (Filtek Flow, Filtek Supreme, n = 11; Tetric Flow, Tetric-Ceram, n = 8). Only patients with vital teeth, presenting mobility of grade 3, having at least one canine with no mobility on both sides of the dental arch were assigned for a splint therapy. The patients were recalled for periodical follow-up controls first at 6 months and thereafter annually. The evaluation protocol involved technical failures [chipping, debonding or fracture (tooth/restoration)] and biological failures (caries)]. Periodontal pocket depth (PPD) and clinical attachment level (CAL) were measured 6 months after splinting and annually. Six sites were measured for each natural tooth at the mesiobuccal, buccal, distobuccal, distolingual, lingual and mesiolingual sites.

Results

All splints were applied from canine to canine in the mandible. In total, 5 recalls were performed and no drop-out was experienced. One partial debonding of the FRC splint with Tetric Flow/Tetric-Ceram combination was observed after 40 months. No caries was found around any of the splints and no teeth had to be extracted until the final follow up. The splinted teeth were found to be vital in the vitality tests. Overall survival rate was 94.8% (Kaplan-Meier). The survival rate was not significantly affected by the composite type (Filtek-Flow/Filtek Supreme: 100%, Tetric Flow/Tetric Ceram: 96% (p = 0.92) [Kaplan-Meier, Log Rank (Mantel-Cox) (CI = 95%)]. Hazard ratio for Tetric Flow/Tetric Ceram group was 0.05 (95% CI) and for Filtek Flow/Filtek Supreme group 0.00 (95% CI). Whilst overall PPD measurements of the dentition ranged between 6 and 12 mm, the CAL measurements ranged between 4.9 and 10 mm at baseline. The mean PPD for the splinted teeth decreased from 8.9 ± 1.8 mm to 5.2 ± 1.2 mm, and CAL decreased from 7.2 ± 1.6 mm to 4.6 ± 1 mm at the end point.

Conclusion

Direct tooth splinting with E-glass FRC material performed successfully up to 4.5 years. Periodontal status of the splinted teeth showed decreased PPD and CAL.     

Interfacial adaptation of in vivo aged polyacid-modified resin composite (compomer) restorations in primary molars

Polyacid-modified resin composite (PMC) restorations are being increasingly used in class II cavities in primary teeth. The aim of this study was to evaluate the interfacial adaptation of 1-month- and 30-month-old in vivo restorations by quantitative scanning electron microscopy (SEM) evaluation. Twelve PMC restorations were performed under clinically controlled conditions in primary molars planned for extraction 1 month later for orthodontic reasons. Eleven other PMC restorations, aged 30 months (range 1.5–3 years) and part of a multicenter study, were collected after exfoliation. To observe the interfacial adaptation of each restoration at several levels a thin layer of the proximal surface was ground off 2–3 times. Replica impressions of each level were prepared for SEM. The interfaces of the replicas were evaluated at ×200 and ×1000. In the 1-month-old restorations gap-free adaptation to enamel was found in 87% and to dentin in 84% of the total interfacial length investigated. For the 30-month-old restorations gap-free adaptation was registered in 59 and 63%, respectively. The interfacial quality was significantly better in the 1-month-old restorations than in those 30 months of age. Adaptation to enamel was significantly better in the cervical part of the 1-month-old restorations than in the axial walls, whereas there was no significant difference in dentin. No significant difference was found between the cervical and axial cavity walls of the 30-month-old restorations. Enamel fractures were registered in 31 and 24%, respectively of the interfacial length of the 1-month- and 30-month-old restorations. The corresponding findings in dentin were 0 and 0.9%. It can be concluded that restorations aged for a short time showed a high percentage of sealing, which decreased significantly for the 30-month-old ones. Received: 24 June 1998 / Accepted: 7 October 1998     

Influence of cavity design on the biomechanics of direct composite resin restorations in Class IV preparations

This study evaluated the effect of cavity design on stress distribution and fracture resistance of direct composite resin restorations in Class IV preparations. A finite element analysis (FEA) model of the maxillary central incisor with a Class IV cavity was established. Five model variations were studied: (i) a 1-mm bevel (ii) a 2-mm bevel, (iii) a plain chamfer, (iv) a stair-step chamfer, and (v) butt joints (a control configuration). All FEA variations modeled a tooth restored with composite resin loaded under 100 N at an angle of 45° to the longitudinal axis. The interfacial von Mises stress was evaluated. The FEA was complemented with an in vitro assessment. Fracture resistance of direct composite resin restorations was tested with a universal testing machine and fracture patterns were observed. Finite element analysis showed that stress in chamfer and stair-step chamfer models was more homogenously distributed, while stress in bevel models was relatively concentrated at lingual regions. Fracture resistance of a 1-mm bevel preparation was lower than for the 2-mm bevel, plain chamfer, and stair-step chamfer preparations, but was higher than for butt joints. The stair-step chamfer group presented the most favorable failure pattern. Considering biomechanics and esthetics, the present study indicates that the stair-step chamfer and 2-mm bevel should be recommended for clinical restoration.