Loading Standardization of Postendodontic Restorations In Vitro: Impact of Restorative Stage, Static Loading, and Dynamic Loading

Sterzenbach, Guido; Rosentritt, Martin; Frankenberger, Roland; Paris, Sebastian; Naumann, Michael

doi:10.2341/10-355-l

Cited by 18 publications

(14 citation statements)

References 31 publications

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“…6 However, their subsequent study reported that dynamic loading prior to load-to-fracture testing of the complete restorative complex significantly decreased maximum load capability inconsequently. 1 Similar results were reported that when fiber posts–cores complex were subjected to cyclic loading, decreases in microtensile bond strength were observed. 7 …”

Section: Introductionsupporting

confidence: 83%

“…The frequency of cyclic loading at 6 Hz in this study situated between 2 and 8 Hz and the 45° oblique loading in static test have been already applied by many researchers. 1,7,9,10 Such study approach is internationally well acknowledged.…”

Section: Discussionmentioning

confidence: 99%

“…1 A static test is often regarded as clinically less relevant, since such abrupt loading never occurs. However, dynamic fatigue testing is claimed to better predict the clinical situation and has been considered as the standard to assess or predict the influence of mouth-motion fatigue on dental restoration.…”

Section: Introductionmentioning

confidence: 99%

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Influence of masticatory fatigue on the fracture resistance of the pulpless teeth restored with quartz-fiber post–core and crown

et al. 2012

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To investigate whether masticatory fatigue affects the fracture resistance and pattern of lower premolars restored with quartz-fiber post–core and full crown, 44 single rooted lower premolars recently extracted from orthodontic patients were divided into two groups of 22 each. The crowns of all teeth were removed and endodontically treated and then restored with quartz-fiber post–core and full crown. Twenty-two teeth in one group were selected randomly and circularly loaded at 45° to the long axis of the teeth of 127.4 N at a 6 Hz frequency, and the other group was not delivered to cyclic loading and considered as control. Subsequently, all teeth in two groups were continually loaded to fail at 45° to the long axis of the teeth at a crosshead speed of 1 mm⋅min−1. The mean destructive force values were (733.88±254.99) and (869.14±280.26) N for the experimental and the control group, respectively, and no statistically significant differences were found between two groups (P>0.05). Bevel fracture and horizontal fracture in the neck of root were the major fracture mode of the specimens. Under the circumstances of this study, it seems that cyclic loading does not affect the fracture strength and pattern of the quartz-fiber post–core–crown complex.

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Section: Introductionsupporting

confidence: 83%

Section: Discussionmentioning

confidence: 99%

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Influence of masticatory fatigue on the fracture resistance of the pulpless teeth restored with quartz-fiber post–core and crown

et al. 2012

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“…The majority of in vitro studies performed to date have only evaluated the maximum load capability of tooth specimens, and extrapolating the observations made during destructive testing to clinical conclusions is not realistic. Artificial ageing is known to have a considerable impact on the data generated in load-to-fracture tests [36]. For this reason, an experimental design combining cyclic loading within physiological limits and simultaneous thermocycling was used in the present study.…”

Section: Discussionmentioning

confidence: 99%

Influence of proximal box elevation on the marginal quality and fracture behavior of root-filled molars restored with CAD/CAM ceramic or composite onlays

et al. 2014

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OBJECTIVES This study investigated the influence of proximal box elevation (PBE) with composite resin when applied to deep proximal defects in root-filled molars with mesio-occluso-distal (MOD) cavities, which were subsequently restored with computer-aided designed/computer-aided manufacturing (CAD/CAM) ceramic or composite restorations. MATERIALS AND METHOD Root canal treatment was performed on 48 human mandibular molars. Standardized MOD cavities were prepared with the distal box located 2 mm below the cemento-enamel junction (CEJ). The teeth were randomly assigned to one of four experimental groups (n = 12). In groups G1 and G2, the distal proximal box was elevated up to the level of the CEJ with composite resin (PBE). No elevation was performed in the remaining two groups (G3, G4). CAD/CAM restorations were fabricated with feldspathic ceramic (Vita Mark II, CER) in groups G1 (PBE-CER) and G3 (CER) or with resin nano-ceramic blocks (Lava Ultimate, LAV) in groups G2 (PBE-LAV) and G4 (LAV). Replicas were taken before and after thermomechanical loading (TML; 1.2 Mio cycles; 49 N; 3,000 thermocycles between 50°C and 5°C). Following TML, load was applied until failure. Fracture analysis was performed under a stereomicroscope (×16). Marginal quality before and after TML (tooth restoration, composite restoration) was evaluated using scanning electron microscopy (×200). RESULTS After TML, lower percentages of continuous margins were observed in groups G1-G3 compared with pre-TML assessments; however, the differences were not statistically significant. For group G4-LAV, the marginal quality after TML was significantly better than in any other group. The highest mean fracture value was recorded for group G4. No significant difference was found for this value between the groups with PBE compared with the groups without PBE, regardless of the material used. The specimens restored with ceramic onlays exhibited fractures that were mainly restricted to the restoration while, in teeth restored with composite onlays, the percentage of catastrophic failures (fractures beyond bone level) was increased. CONCLUSION PBE had no impact on either the marginal integrity or the fracture behavior of root canal-treated mandibular molars restored with feldspathic ceramic onlays. CAD/CAM-fabricated composite onlays were more favorable than ceramic onlays in terms of both marginal quality and fracture resistance, particularly in specimens without PBE. CLINICAL RELEVANCE Composite onlays with or without PBE may be a viable approach for the restoration of root-filled molars with subgingival MOD cavities. AbstractObjectives This study investigated the influence of proximal box elevation (PBE) with composite resin when applied to deep proximal defects in root--filled molars with MOD cavities, which were subsequently restored with CAD/CAM ceramic or composite restorations.

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“…3 The null hypothesis of this experiment was that neither the presence of fiber post nor residual coronal walls would affect the fracture resistance of premolars.…”

Section: Introductionmentioning

confidence: 96%

Influence of fiber posts on the fracture resistance of endodontically treated premolars with different dental defects

2013

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This study aimed to evaluate the influence of quartz fiber post placement on the fracture resistance of endodontically treated premolars with different dental defects under dynamic loading. Fifty extracted single-rooted mandibular premolars were randomized into five groups. Each group was prepared according to numbers of residual walls ranged from 0 to 4. Then each group was divided into two subgroups with one restored with quartz fiber posts and the other without posts. In no-post groups, gutta percha point 2 mm below cemento-enamel junction was removed. Composite resin was adapted to the well and used to shape the core directly. Each tooth was restored with a complete metal crown. Dynamic loading was carried out in a masticatory simulator with a nominal load of 50 N at 2 Hz for 300 000 loading cycles. Then a quasi-statically load was applied in a universal testing machine 30° to the long axis with a crosshead speed of 1 mm⋅min−1 until fracture. Data were analyzed with one-way analysis of variance and pairwise comparison (P<0.05). No specimens failed during dynamic loading. The fracture resistance enhanced with the increase of numbers of coronal walls and the differences were significant (P<0.05). Placement of fiber posts had a significant effect when fewer than two walls remained (P<0.05), but it had no significant influence in groups with two, three or four walls (P>0.05). Fiber post did not change failure mode, and the fracture pattern was mainly favorable. More dentin walls need to be retained in clinic. When no less than two walls remained, a fiber post is not always necessary.

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Loading Standardization of Postendodontic Restorations In Vitro: Impact of Restorative Stage, Static Loading, and Dynamic Loading

Cited by 18 publications

References 31 publications

Influence of masticatory fatigue on the fracture resistance of the pulpless teeth restored with quartz-fiber post–core and crown

Influence of masticatory fatigue on the fracture resistance of the pulpless teeth restored with quartz-fiber post–core and crown

Influence of proximal box elevation on the marginal quality and fracture behavior of root-filled molars restored with CAD/CAM ceramic or composite onlays

Influence of fiber posts on the fracture resistance of endodontically treated premolars with different dental defects

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