Evaluation of Different Post Lengths’ Effect on Fracture Resistance of a Glass
Fiber Post System

ABSTRACTObjectives: The purpose of this in vitro study was to evaluate the influence of different post lengths upon root fracture resistance.Methods: 78 maxillary central teeth with similar dimensions were mounted in acrylic blocks with artificial silicone periodontal ligaments. Combinations of post lengths of 6 mm (shorter than 1/1 clinical crown length), 9 mm (1/1 clinical crown length), and 12 mm (longer than 1/1 clinical crown length) made up 6 different groups consisting of 13 teeth each. The glass fiber posts (Snowpost) were cemented with Super-Bond C&B and Panavia F luting cement. Composite-resin cores were made with Clearfil PhotoCore. The specimens were tested in a universal test machine. The testing machine applied controlled loads to the core, 2 mm from its incisal edge, on the palatal side at an angle 135 degrees to the long axis of the root. The testing machine was set at a crosshead speed of 5mm per minute. All samples were loaded until failure.Results: There was no statistically significant difference between cements (P>.05). Posts shorter than clinical crown length, demonstrated root fracture under significantly lower loading forces (P<.05).Conclusion: Usage of posts shorter than clinical crowns should be avoided to eliminate clinical failure. (Eur J Dent 2008;2:23-28)

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Evaluation of Fracture Resistance and Sites of Failure of Different Dowel Core Restorations: An In-Vitro Study

The Open Dentistry Journal ◽

10.2174/1874210601913010454 ◽

2019 ◽

Vol 13 (1) ◽

pp. 454-461

Author(s):

Manjeev Guragain ◽

Suraj Mathema ◽

Dinesh Rokaya

Keyword(s):

Glass Fiber ◽

Fracture Resistance ◽

Statistical Tests ◽

Testing Machine ◽

In Vitro Study ◽

Resin Core ◽

Significant Difference ◽

Endodontically Treated Tooth

Background: Dowel Cores are often required in endodontically treated tooth to aid retention and resistance for a final prosthetic crown. Studies concerning the role of post-core systems on the fracture resistance with different dowel material remain controversial. Aim: This experimental study aimed to investigate the fracture resistance strength and failure mode of 3 dowel systems (glass fiber, indirect resin, and prefabricated metal with resin core). Methods: Twenty-one extracted human maxillary central incisors were first endodontically treated and then separated into 3 equal groups randomly;1st group consisted of glass fiber dowel, 2nd group consisted of indirect resin dowel, and 3rd group consisted of the prefabricated metal dowel. All specimens were restored with resin core and indirect resin crown. A testing force was applied with a universal testing machine (at 135 o angle) at 3 mm from the incisal edge of crown and forces were measured. Statistical tests were done using One-way ANOVA and Chi-square Test. Results: There was no significant difference (P-value >0.05) of the fracture resistance among glass fiber dowel, indirect resin dowel and pre-fabricated dowel with indirect resin crown. The prefabricated metal dowel had maximum fracture resistance (566 ±157.771 N) followed by Glass fiber dowel (541.047 ±199.571 N) and indirect resin dowel and post (444.550 ±139.788 N). Conclusion: Glass fiber dowel, indirect resin dowel and prefabricated metal dowel with resin core and indirect resin crown systems showed statistically insignificant fracture strength values and mode of failure.

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“Ormocer an innovative technology”: A replacement for conventional cements and veneer? A comparative in vitro analysis

European Journal of Dentistry ◽

10.4103/ejd.ejd_113_16 ◽

2017 ◽

Vol 11 (01) ◽

pp. 058-063 ◽

Cited By ~ 1

Author(s):

Vini Rajeev ◽

Rajeev Arunachalam ◽

Sanjna Nayar ◽

P. R. Arunima ◽

Sivadas Ganapathy ◽

...

Keyword(s):

Bond Strength ◽

Testing Machine ◽

In Vitro Study ◽

Sem Analysis ◽

Innovative Technology ◽

Group I ◽

Luting Cement ◽

Significant Difference ◽

Vitro Analysis

ABSTRACT Objective: This in vitro study was designed to assess shear bond strength (SBS) of ormocer flowable (OF) resin as a luting agent, ormocer as an indirect veneer material with portrayal of modes of failures using scanning electron microscope (SEM). Materials and Methods: Sixty maxillary central incisors were divided into Group I, II, and III with 20 samples each based on luting cement used. They were OF, self-adhesive (SA) cement, and total etch (TE) cement. These groups were subdivided into “a” and “b” of ten each based on the type of veneering materials used. Veneer discs were fabricated using Ormocer restorative (O) and pressable ceramic (C). Specimens were thermocycled and loaded under universal testing machine for SBS. The statistical analysis was done using one-way ANOVA post hoc Tukey honest significant difference method. Results: A significant difference was observed between the Groups I and II (P < 0.05). The highest mean bond strength when using ormocer veneer was obtained with the Group Ia (19.11 ± 1.92 Mpa) and lowest by Group IIa (8.1 ± 1.04 Mpa), whereas the highest mean bond strength while using ceramic veneer was of similar range for Group Ib (18.04 ± 4.08 Mpa) and Group IIIb (18.07 ± 1.40 Mpa). SEM analysis revealed OF and TE presented mixed type of failure when compared with SA where failure mode was totally adhesive. Conclusion: OF was found equally efficient like TE. Bond strength of ormocer as a veneer was not inferior to ceramic making it one of the promising additions in the field of dentistry.

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A Comparative in vitro Study of the Load at Fracture of All-ceramic Crowns with Various Thicknesses of In-Ceram Core

The Journal of Contemporary Dental Practice ◽

10.5005/jcdp-9-4-17 ◽

2008 ◽

Vol 9 (4) ◽

pp. 17-25 ◽

Cited By ~ 1

Author(s):

Ilser Turkyilmaz ◽

Suat Gokce ◽

Emine Celik-Bagci

Keyword(s):

Fracture Resistance ◽

Testing Machine ◽

In Vitro Study ◽

Chromium Alloy ◽

Dental Practitioners ◽

Significant Difference ◽

All Ceramic ◽

Feasible Option ◽

Ceramic Crowns

Abstract Aim The aim of this study was to investigate the influence of three different thicknesses of In-Ceram core on the load at fracture of all-ceramic crowns. Methods and Materials Thirty standardized crown-shaped nickel-chromium alloy dies were fabricated using a milling machine. Twenty dies were prepared with a 1 mm shoulder for Groups A and B. The only difference in the ten dies used for Group C was a smaller 0.5 mm lingual shoulder. The thicknesses of In-Ceram were 0.5 mm, 1.5 mm, and 0.75 mm for Groups A, B, and C. All all-ceramic crowns were fabricated in accordance with the manufacturer's instructions. After cementation of the crowns, their fracture resistance was tested with a universal testing machine. The load was directed to a point located 3 mm from the lingual aspect of the incisal edge at 30 degrees to the long axis of each specimen until catastrophic failure occurred. Results The mean loads at fracture for Groups A, B, and C were 1117±388 N, 2083±385 N, and 1439±368 N, respectively. No statistically significant difference in load at fracture between Groups A and C was found (p>0.05). However, the differences were statistically significant between Groups A and B (p<0.001) and Groups B and C (p<0.001). Conclusion Under the guidelines of this study, increasing the thickness of the In-Ceram core increased the fracture resistance of the all-ceramic crowns. Clinical Significance The sufficient thickness of the In-Ceram core of all-ceramic crowns is an important factor in fracture resistance. Therefore, dental practitioners should be careful in patient selection; if the horizontal overlap of a tooth to be restored is too limited, then all-ceramic crowns may not be a feasible option. Citation Gokce S, Celik-Bagci E, Turkyilmaz I. A Comparative in vitro Study of the Load at Fracture of Allceramic Crowns with Various Thicknesses of In-Ceram Core. J Contemp Dent Pract 2008 May; (9)4:017-025.

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Effect of MTA versus CEM apical plugs on fracture resistance of endodontically treated simulated immature teeth restored with cast metal posts: an in-vitro study

BMC Oral Health ◽

10.1186/s12903-021-01641-w ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Ensieh Grayli ◽

Abbas Dashtban ◽

Leyla Shadan ◽

Naser Behnampour ◽

Elham Afshari

Keyword(s):

Fracture Resistance ◽

Testing Machine ◽

In Vitro Study ◽

Control Group ◽

Significance Level ◽

Cast Metal ◽

Immature Teeth ◽

Gutta Percha ◽

Significant Difference

Abstract Background Endodontically treated immature teeth which are restored with cast metal posts are of the most susceptible teeth to fracture. An apical plug is usually used as root end filling in order to seal the wide apical foramen. The current study was performed to evaluate the effect of different apical plug materials (MTA and Calcium enriched mixture cement) at varied thicknesses on fracture resistance of teeth restored with cast metal posts. Methods A total of 40 extracted intact single-rooted human mandibular premolars (removed for orthodontic reasons) were used in the study. The coronal part of each tooth was removed and root canal preparation was performed. A size 4 Gates Glidden drill was used to enlarge the canal and was passed through the apical foramen in order to simulate an immature apex. Samples were randomly divided into 5 groups (n = 8) according to apical plug (control group: No plug, group MTA5: 5 mm MTA plug, group CEM5: 5 mm CEM plug, group MTA3: 3 mm MTA plug, group CEM3: 3 mm CEM plug). Post-space preparations were performed and cast metal post-and-cores were fabricated and cemented. Fracture resistance was assessed using a universal testing machine. Fracture thresholds were recorded and data were analyzed using One-way ANOVA and Dunnett’s T3 tests with significance level at P value < 0.05. Results The analysis showed a significant difference of fracture resistance between groups (P value < 0.05). The mean fracture resistance of samples in control group was significantly lower than MTA5 (P value = 0.003). There was no significant difference between other groups (P value > 0.05). Conclusions Within the limits of this study, the evidence indicated that placement of a 5 mm MTA apical plug increased the fracture resistance in simulated immature teeth which are restored with cast metal posts, compared to control group (gutta-percha and sealer). While the results were not as promising for a 3 mm MTA apical plug or either 3 or 5 mm CEM apical plug.

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Mathematical validation of measurement of root fracture resistance: an in vitro study

BMC Oral Health ◽

10.1186/s12903-021-01873-w ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Rafat Bagheri ◽

Abbas Abbaszadegan ◽

Mohammad R. Nabavizadeh ◽

Maryam Ferooz ◽

Peter Parashos

Keyword(s):

Fracture Resistance ◽

Testing Machine ◽

In Vitro Study ◽

Maximum Load ◽

Control Groups ◽

Root Fracture ◽

Root Canals ◽

Gutta Percha ◽

Root Fracture Resistance

Abstract Background The aim of this study was to develop a mathematically valid method of assessing fracture resistance of roots. The model developed used mesial roots of lower molars instrumented using stainless steel hand files (SS) and two rotary nickel-titanium (NiTi) systems. Methods Eighty human lower molars were selected and randomly divided into four groups (n = 20). After instrumentation, the root canals were obturated using thermoplasticized gutta percha. The roots were covered with a simulated periodontal ligament and mounted vertically in autopolymerizing acrylic in PVC tubes. Using a universal testing machine, the force to fracture (N) was applied and the maximum load (FL) was recorded. Remaining dentine volume was calculated and the fracture resistance (FR) was recorded. The data were analyzed using SPSS version 22 with P < .05. Results There were no significant differences among the instrumentation methods for FL but in FR the roots instrumented using rotary NiTi showed significantly lower values than control groups and SS files (P < 0.001). Conclusions Considering the effect of root length, volume of the root, and volume of the instrumented canal as well as the maximum failure load may be a more objective method of reporting fracture resistance of roots.

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Comparison of Fracture Strengths among different Commonly Placed Anterior Esthetic Restorations for Primary Dentition: An in vitro study

Journal of Clinical Pediatric Dentistry ◽

10.17796/1053-4625-45.3.5 ◽

2021 ◽

Vol 45 (3) ◽

pp. 171-176

Author(s):

Brent Lin ◽

Amit Khatri ◽

Michael Hong

Keyword(s):

Fracture Strength ◽

Testing Machine ◽

In Vitro Study ◽

Vitro Study ◽

Anterior Teeth ◽

Study Results ◽

Luting Cement ◽

Significant Difference ◽

All Ceramic

The purpose of this study was to determine and compare the shear force (N) required to fracture or dislodge an all-ceramic zirconia-based crown using different luting cement with those of polycarbonate crown and strip crown for the primary anterior teeth in vitro. Study design: Four groups of esthetic restoration for primary anterior teeth were tested for fracture strength: 1) Fifteen all-ceramic zirconia-based crowns cemented with glass ionomer cement, 2) Fifteen all-ceramic zirconia-based crowns bonded with a self-adhesive resin cement, 3) Fifteen polycarbonate crowns cemented with a polymer reinforced zinc-oxide eugenol and 4) Fifteen resin strip crowns. All restorations were placed and cemented on reproductions of dies in an independent laboratory at Delhi, India. All samples underwent loading until fracture or dislodgement with the Universal Testing Machine. The force in Newton (N) required to produce failure was recorded for each sample and the type of failures was also noted and characterized. One-way analysis of variance (ANOVA) test and the Tukey and Scheffe’s post hoc comparisons were used for statistical analyses. Results: In this invitro study, results were measured in Newtons (N). Group 1 (410.9±79.5 N) and Group 2 (420.5±57.8 N) had higher fracture strength than Group 3 (330.3±85.6 N) and Group 4 (268.4±28.2 N). These differences were statistically significant at P≤.05 among the sample groups. No significant difference was found between groups 1 and 2 (P = 0.984) nor between groups 3 and 4 (P =0.104). Among type of failures, majority of restoration fractures for zirconia-based crowns and resin strip crowns were due to cohesive failures and polycarbonate crowns had predominantly mixed failures. Conclusions: Under the limitations of this in vitro study, it could be concluded that all-ceramic zirconia-based crowns attained the highest fracture strength among all restorative samples tested regardless of the type of luting agent employed (P<.01). Cohesive failures were commonly observed in the zirconia crowns and resin strip crowns, whereas polycarbonate crowns revealed predominately mixed failures.

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Fracture resistance of roots enlarged with various rotary systems and filled with various sealers

Journal of Dental Research Dental Clinics Dental Prospects ◽

10.15171/joddd.2019.033 ◽

2019 ◽

Vol 13 (3) ◽

pp. 215-220

Author(s):

Selen İnce Yusufoglu ◽

Melek Akman ◽

Makbule Bilge Akbulut ◽

Ayce Ünverdi Eldeniz

Keyword(s):

Fracture Resistance ◽

Testing Machine ◽

In Vitro Study ◽

Universal System ◽

Gutta Percha ◽

Significant Difference ◽

Ah Plus ◽

Group 2 ◽

Group 1

Background. This in vitro study compared the fracture resistance of roots instrumented either with ProTaper or One Shape rotary systems and filled with one of the silicate, epoxy resin or silicone-based sealers. Methods. Sixty single-rooted extracted mandibular premolars were decoronated to a length of 13 mm and then randomly divided into two main groups (n=30) in terms of the rotary system used for preparation. Group 1 samples were instrumented with the ProTaper Universal system up to a master apical file of #F2, while samples in group 2 were enlarged with One Shape system. The two main groups were then divided into 3 subgroups in terms of the sealer used (n=10) and filled with gutta-percha (either F2 or MM-GP points) of the rotary system used and one of the sealers as follows: group 1, BioRoot RCS + ProTaper F2 gutta-percha; group 2, AH Plus + ProTaper F2 gutta-percha; group 3, GuttaFlow + ProTaper F2 gutta-percha; group 4, BioRoot RCS+ MM-GP points; group 5, AH Plus + MM-GP points; and group 6, GuttaFlow + MM-GP points. Each specimen then underwent fracture testing by using a universal testing machine at a crosshead speed of 1.0 mm/min until the root fractured. Data were statistically analyzed. Results. Two-way ANOVA showed no significant differences between the groups. One Shape instruments showed significantly better fracture resistance compared to ProTaper instruments. Statistically, no significant difference was found between AHPlus, GuttaFlow and BioRoot RCS sealers. Conclusion. It can be concluded that the rotary system used for the instrumentation of teeth has some influence on the fracture resistance, while the root canal sealers do not have such an effect.

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Reinforcement effect of intra-orifice barrier materials in teeth treated with regenerative endodontic procedure: Research article

Journal of Dental Research Dental Clinics Dental Prospects ◽

10.34172/joddd.2021.019 ◽

2021 ◽

Vol 15 (2) ◽

pp. 111-114

Author(s):

Sevinç Aktemur Türker ◽

Keziban Olcay ◽

Sena Kaşıkçı ◽

Fatma Zühal Yurdagül

Keyword(s):

Fracture Resistance ◽

Testing Machine ◽

Glass Ionomer Cement ◽

In Vitro Study ◽

Cervical Region ◽

Control Group ◽

Barrier Materials ◽

Immature Teeth ◽

Significant Difference

Background. Regenerative endodontic treatment (RET) is a clinically advanced procedure for necrotic immature teeth. However, root canal walls of these teeth are brittle especially in the cervical region and need reinforcement. This in vitro study is conducted to evaluate the effect of intra-orifice barrier materials on the fracture resistance of immature teeth treated with regenerative procedure. Methods. Forty-eight maxillary central incisors were used. Twelve intact teeth were selected for the control group. Remained teeth were prepared using peeso drills to simulate immature teeth and assigned into three groups according to the intra-orifice barrier material placed over MTA (n=12); Composite resin (CR), ProRoot MTA and Resin-modified glass ionomer cement (RMGIC). Fracture strength test was applied using a universal testing machine. One-way ANOVA and Tukey post hoc tests were used at P=0.05. Results. A significant difference was obtained among groups (P<0.05). MTA showed the lowest fracture resistance (P<0.05). However, no significant difference was found among RMGIC, CR, and control groups (P>0.05). Conclusion. Intra-orifice restorative materials have reinforcement affect in immature teeth treated with regenerative endodontic procedure. RMGIC or CR can be regarded as a viable choice to reduce the occurrence of cervical root fracture of immature teeth treated with a regenerative therapy.

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Assessing Fracture Resistance of Restored Premolars with Novel Composite Materials: An In Vitro Study

International Journal of Dentistry ◽

10.1155/2021/5512708 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Zahraa Abdulaali Al-Ibraheemi ◽

Huda Abbas Abdullah ◽

Nada Abdlameer Jawad ◽

Julfikar Haider

Keyword(s):

Fracture Resistance ◽

Testing Machine ◽

In Vitro Study ◽

Vitro Study ◽

Resistance Testing ◽

Significant Difference ◽

Group A ◽

Group B ◽

Group D

During restorative treatment, premolars restored with resin filling materials using the conventional incremental-fill technique take longer restoration time and undermine the integrity of the tooth. The aim of this study was to assess fracture resistance of premolars restored by various types of novel bulk-fill composite resin materials. Forty-eight (n = 48) freshly extracted sound maxillary first premolars were used in this in vitro study. The teeth were divided into six groups, each having 8 specimens. Group A (positive control) was allocated for the intact teeth. For specimens in Groups B to F, a large cavity (Class-II MOD) was prepared with a standardized dimension of cavity (3 mm depth on the pulpal floor, 4 mm at the gingival seat, and 3 mm cavity width). Group B represented prepared teeth without any restoration. Group C, Group D, Group E, and Group F were restored with Tetric EvoCeram® incremental-fill (conventional), Beautifil bulk-fill, Filtek posterior bulk-fill, and SonicFill 2 bulk-fill restorative materials, respectively. All samples were finished and polished with an enhanced finishing kit and stored in distilled water for a month before the fracture resistance testing. All the samples were exposed to the axial loading (the speed of crosshead was 1 mm/min) in a computer-controlled universal testing machine (LARYEE, China) via a steel bar (6 mm in diameter) and the maximum applied force in Newton was recorded as the fracture resistance. One-way analysis of variance (SPSS 21) was used to compare the fracture resistance within the groups, and Tukey’s post hoc test was used to determine the difference between the groups. The lowest value of fracture resistance was recorded for Group B, and the highest value was recorded for Group A followed by the values of Group D, Group C, Group F, and Group E. One-way ANOVA revealed a statistically significant difference between the groups ( P < 0.05 ). Nonsignificant difference was found between the premolars restored by bulk-fill and conventional composites. Among the bulk-fill restored specimens, Beautifil restorative demonstrated significantly higher fracture resistance in comparison with the other two bulk-fill restored specimen groups (SonicFill 2 and Filtek). Bulk-fill composite such as Beautifil could be an alternative option to conventional incremental-fill composite for premolar restoration.

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Mathematical Validation of Measurement of Root Fracture Resistance: An in Vitro Study.

10.21203/rs.3.rs-423310/v1 ◽

2021 ◽

Author(s):

Rafat Bagheri ◽

Abbas Abbaszadegan ◽

Mohammad R Nabavizadeh ◽

Maryam Ferooz ◽

Peter Parashos

Keyword(s):

Fracture Resistance ◽

Testing Machine ◽

In Vitro Study ◽

Maximum Load ◽

Control Groups ◽

Root Fracture ◽

Root Canals ◽

Gutta Percha ◽

Root Fracture Resistance

Abstract Background: This study aimed to develop a mathematically valid method of assessing fracture resistance of roots. The model developed used mesial roots of lower molars instrumented using stainless steel hand files (SS) and two rotary nickel-titanium (NiTi) systems. Methods: Eighty human lower molars were selected and randomly divided into four groups (n=20). After instrumentation, the root canals were obturated using thermoplasticized gutta percha. The roots were covered with a simulated periodontal ligament and mounted vertically in autopolymerizing acrylic in PVC tubes. Using a universal testing machine, the force to fracture (N) was applied and the maximum load (FL) was recorded. Remaining dentin volume was calculated and the fracture resistance (FR) was recorded. The data were analyzed using SPSS version 22 with P < .05.Results: There were no significant differences among the instrumentation methods for FL but in FR the roots instrumented using rotary NiTi showed significantly lower values than control groups and SS files (P <0.001). Conclusions: Considering the effect of root length, volume of the root, and volume of the instrumented canal as well as the maximum failure load may be a more objective method of reporting fracture resistance of roots.

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