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Fracture resistance of endodontically treated premolars with extensive MOD cavities restored with different composite restorations (An In vitro study)

Authors: Aws H. Atiyah اوس عطيه --- Luma M. Baban لمى بابان
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2014 Volume: 26 Issue: 1 Pages: 7-15
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: This in vitro study evaluated the fracture resistance of weakened endodontically treated premolars with class II MOD cavities restored with different composite restorations (Low-shrinkage Filtek P90, nanohybrid Filtek Z250 XT and SDR bulk fill). The type and mode of fracture were also assessed for all the experimental groups.Materials and Method: Fifty human adult maxillary premolar teeth were selected for this study. Standardized extensive class II MOD cavities with endodontic treatment were prepared for all teeth, except those that were saved as intact control. The teeth were divided into five groups of ten teeth each (n=10): (Group 1) intact control group, (Group 2) unrestored teeth with endodontic treatment, (Group 3) restored with (Filtek Z250 XT), (Group 4) restored with SDR bulk-fill flowable composite and (Group 5) restored with Filtek P90 composite. All specimens were subjected to compressive axial loading until fracture in a universal testing machine. The data were statistically analyzed using one-way ANOVA test and LSD test. Macroscopic fracture type were observed and classified into favorable and unfavorable. Specimens in group 3, 4 and 5 were examined by stereomicroscope at a magnification of 20× to evaluate the mode of failure into adhesive, cohesive or mixed.Results: The mean fracture load was (1.123 Kn) for group 1, (0.545 Kn) for group 2, (0.687 Kn) for group 3, (0.799 Kn) for group 4 and (0.672 Kn) for group 5. Using one way ANOVA test a highly significant difference (P < 0.01) were found among all groups. The use of bulk-fill flowable composite improved the fracture resistance significantly in comparison to silorane and non-significantly to Filtek Z250 XT. Filtek Z250 XT showed better improvement in fracture resistance but with no significant differences in comparison to Filtek P90 composite restorations. The type of failure was unfavorable for all the restored groups.Conclusion:All experimental composite restorations showed significant improvement in the resistance to cuspal fracture in comparison to unrestored one. However, under the conditions of this study, direct composite restorations should be considered as a valid interim restoration for weakened endodontically treated teeth before cuspal coverage can be provided.


Article
The influence of recent adhesive onlay fabrication techniques on the fracture resistance of endodontically treated premolars (An in vitro study)

Authors: Zainab Shaker Al-Taii زينب شاكر الطائي --- Inas I. Al-Rawi ايناس الراوي
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2014 Volume: 26 Issue: 2 Pages: 12-17
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Endodontically treated teeth have low resistance to fracture against occlusal forces. The strengtheningeffect of bonded esthetic onlay restoration on weakened tooth has been reported. This study aimed to assess thefracture resistance of endodontically treated premolars restored with composite with and without cuspal coverageby using direct and indirect techniques. Indirect technique done by CAD/CAM system (computer aided design –computer aided manufacturer) and laboratory processing.Material and methods: Forty human extracted maxillary premolars of approximately comparable sizes were dividedinto four groups: Group (A): Ten endodontically treated teeth directly filled with Filtek Z250xt without cuspalcoverage. Group (B): Ten endodontically treated teeth prepared with onlay cavities and restored directly with FiltekZ250 XT. Group(C): Ten endodontically treated teeth prepared with onlay cavities and restored indirectly with FiltekZ250 XT. Group (D): Ten endodontically treated teeth prepared with onlay cavities and restored indirectly withParadigm MZ100 CAD/CAM blocks. Fracture strength of the samples was measured by using universal testingmachine (an axial compression test). Data were analyzed statistically by one way ANOVA test and least significantdifference test,Results showed that Group A has the lowest fracture resistance value than all experimental Groups and thedifference are highly significant. While Group B has a high significant fracture resistant value than the indirectlyrestored groups. Group C and Group D showed an approximate fracture resistant result (1.13KN and 1.07KNrespectively) and the difference is statistically not significant.Conclusion All CAD/CAM composite onlay, indirect Filtek z250 XT and direct cuspal coverage survived maximumbiting force for posterior single tooth, so these types of onlays provide good reinforcement in an extensive MODcavities in premolars The mode of fracture for Group D was 90% restorable which is higher than group C (80%)restorable and group B (30%) restorable type of fracture


Article
Fracture resistance of weakened premolars restored with sonically-activated composite, bulk-filled and incrementally-filled composites (A comparative in vitro study)

Authors: Fatima Fahad فاطمة فهد --- Manhal Abdul-Rahman Majeed منهل عبد الرحمن مجيد
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2014 Volume: 26 Issue: 4 Pages: 22-27
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: This study was conducted to assess the effect of sonic activation and bulk placement of resincomposite in comparison to horizontal incremental placement on the fracture resistance of weakened premolarteeth.Materials and method: Sixty sound human single-rooted maxillary premolars extracted for orthodontic purposes wereused in this study. Teeth were divided into six groups of ten teeth each: Group 1 (sound unprepared teeth as acontrol group), Group 2 (teeth prepared with MOD cavity and left unrestored), Group 3 (restored with SonicFill™composite), Group 4 (restored with Quixfil™ composite), Group 5 (restored with Tertic EvoCeram® Bulk Fill composite)and Group 6 (restored with Universal Tetric EvoCeram® composite using horizontal incremental layering technique).Standardized class II MOD cavity was prepared in all teeth except (group 1).After finishing the restorative procedureof each group according to the manufacturer's instructions, all teeth were stored in deionized distilled water in anincubator at 37°C for seven days.All specimens were subjected to compressive axial loading until fracturein auniversal testingmachine.Specimens were examined by a stereomicroscope at a magnification of (20X) to evaluatethe mode of fracture .Results: The results of this study revealed that the control group exhibited the highest fracture resistance compared toall prepared teeth groups (restored or unrestored) and the differences were statistically highly significant (P<0.01),except with group 3 (which was restored with SonicFill™ composite) where the difference was statistically significantonly (P < 0.05).Additionally the results of this study revealed that the prepared unrestored teeth (Group 2) exhibitedthe lowest fracture resistance compared to all restored groups and the differences were statistically highly significant(P<0.01). Meanwhile, among the restored teeth groups, teeth restored with SonicFill™ composite (group 3) exhibitedthe highest fracture resistance as compared with all other restored groups and the difference was statistically highlysignificant (P<0.01) .On the other hand, no statistically significant differences in fracture resistance were found amonggroups 4, 5 and 6, which were restored with Quixfil™ composite, Tetric EvoCeram® Bulk Fill composite and UniversalTetric EvoCeram® composite, respectively (P > 0.05). Group 3and Group 5 showed mostly mixed mode of failure,while Group 4 showed mostly adhesive mode of failure. On the other hand Group 6 teeth showed different modes offailure.Conclusions: SonicFill™ composite can be considered as a viable treatment modality for the restoration of weakenedmaxillary premolar teeth. On the other hand, the time-consuming incremental layering technique can be substitutedwith bulk filling, using bulk fill materials (Quixfil™ and Tetric EvoCeram® Bulk Fill) for reinforcement ofweakenedmaxillary premolars


Article
Fracture Resistance of Roots After Canal Preparation by Two Methods and Obturated by Different Techniques ISSN

Author: Wiaam M.O. AL-Ashou
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2014 Volume: 14 Issue: 2 Pages: 212-219
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: The purposes of this in vitro study are to investigate the effect of instrumentation types ( hand and rotary instrumentations) and obturation techniques (Cold lateral, and Thermafil) on vertical root fracture. Materials and Methods: The crown of the 100 single rooted teeth were removed leaving 12mm of the roots length, then the root randomly divided into four groups. Control –ve Group(n=10), Hand Group(n=30), ProTaper Group(n=30) and Helix Group(n=30) according to the type of the instrument used to prepared the root canals. After that, the last three groups subdivided into subgroups according to the obturation technique either by using Cold Lateral condensation technique or Thermafil obturation technique. After the sealer set, the roots were embedded in acrylic moulds and subjected to compressive loading, the load at which the fracture occurred was recorded and statically analysis. Results: the fracture resistance of the root prepared by Helix and ProTaper files were significantly greater than that obtained for the root canals prepared with hand K-files. The results of this study also demonstrated that when root canals obturated with Thermafil the roots resist the fracture load greater than that of the canals obturated with Cold Lateral condensation obturation but the difference is not statistically significant between them. Conclusions: the use of rotary nickel titanium files in endodontic treatment provides higher fracture resistance for the roots, and the use of the Cold Lateral condensation obturation technique may weaken the roots, so that the roots become more susceptible to the vertical root fracture.

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