A novel insertion design of fiber materials for the adhesive reattachment in vertically fractured teeth.

OBJECTIVE: This ex vivo study aimed to evaluate the strengthening effect of different ferrule and reattachment designs with fiber and adhesive materials on vertically fractured teeth. METHODS: Ninety extracted single-root premolars were instrumented and divided into nine groups (two control groups and seven experimental groups; n = 10). The negative control (NC) group comprised of intact teeth, while the positive control (PC) group comprised of root canal-treated teeth. The roots of the teeth in the experimental groups were vertically fractured into two equal fragments. The fragments were reattached with one of the followings: 4-methacryloxyethyl trimellitate anhydride/methacrylate-tri-n-butyl borane (4-META/MMA-TBB) resin, 4-META/MMA-TBB + quartz fiber post, 4-META/MMA-TBB + glass fiber bundles, 4-META/MMA-TBB + quartz fiber post + 1 mm ferrule, 4-META/MMA-TBB + glass fiber bundles + 1 mm ferrule, 4-META/MMA-TBB + quartz fiber post + 2 mm ferrule, and 4-META/MMA-TBB + glass fiber bundles + 2 mm ferrule. The core build-ups were made with composite resin. The specimens were subjected to compressive loading until failure occurred. Mean load necessary to fracture each sample and the fracture types of these samples were recorded. RESULTS: The highest mean fracture load was recorded in the NC group (1,036.7 N), which was not significantly higher than the PC group (989.66 N) (p > 0.05). The roots reattached with quartz fiber post demonstrated significantly less fracture strength (871.9 N) as compared to the other test and control groups (p < 0.05). There was no significant difference between the PC group and reattached fragments with different ferrule designs in terms of fracture resistance (p > 0.05). CONCLUSIONS: The customized fiber bundles may be more suitable for reattachment of vertically fractured teeth than the rigid fiber posts. For reattachment procedures, the ferrule design may be preferred to increase the fracture strength of vertically fractured teeth.

Strengthening effect of different fiber placement designs on root canal treated and bleached premolars.

To evaluate the strengthening effect of five different fibers with different placement designs in root canal treated and intracoronally bleached premolars. Seventy extracted single-rooted premolars were distributed into 7 groups (G1-G7). Group 1 (G1) included the intact (I) teeth as the negative control. Group 2 (G2) included root canal treated, intra-coronally bleached and composite (C) restored teeth as the positive control. In the other five test groups after root canal treatment the teeth were intra-coronally bleached and fiber materials were placed into standard MOD cavities in the following different designs: an intracanal rigid fiber/Reforpost (G3,RF), an intracanal flexible fiber/ Everstick (G4, FF), four intracanal flexible pin fibers/Dentapreg Pin (G5,PF), an intercuspal flexible fiber /Dentapreg SFU (G6, IF) or an intra-coronal horseshoe-shaped/ Dentapreg SFU (G7,CF). All cavities were filled with a microfilled resin composite. Fracture resistance was tested using a universal testing machine under a crosshead speed of 1 mm/minute. One-way ANOVA and Duncan's Multiple Range tests were used for statistical analysis. Fracture types were recorded. The fracture resistance values in descending order were G1(I): 1190.97 N > G6 (IF): 1138.78 N > G5 (PF): 942.45 N > G3 (RF): 737.40 N > G4 (FF):694.29 N > G2 (C): 611.83 N > G7 (CF): 542.78 N. There were statistically significant differences among the groups (p ≤ 0.05). In all groups, repairable coronal oblique fractures were mostly observed. Flexible fibers placed intercuspally exhibited a significantly better strengthening effect than those of the intracanal flexible and rigid fibers (p < 0.05).

Evaluation of antimicrobial efficacy of cetrimide and Glycyrrhiza glabra L. extract against Enterococcus faecalis biofilm grown on dentin discs in comparison with NaOCl.

This study aimed to determine the antimicrobial efficacy of NaOCl, cetrimide, and Glycyrrhiza glabra L. extract against Enterococcus faecalis biofilms on dentine discs. Broth microdilution method was used to determine minimal bactericidal concentrations (MBCs) of the agents. A biofilm susceptibility assay was performed using E. faecalis biofilms grown on dentine discs. Minimal bactericidal concentrations (MBCs) of NaOCl (0.5%), cetrimide (0.015%), and G. glabra L. extract (0.25%) were applied for 1, 3, and 5 min, and the mean viable cell counts were recorded and statistically analyzed. There was no significant difference between cetrimide and NaOCl at 1 min (p>0.05). NaOCl was the most effective agent at 3 and 5 min (p<0.05) while G. glabra L. extract was the least (p<0.05). The MBCs of NaOCl, cetrimide, and G. glabra that eliminated the planktonic E. faecalis did not eradicate the biofilms grown on dentin discs.

Fracture resistance and failure mode of endodontically treated teeth restored using ceramic onlays with or without fiber posts-an ex vivo study.

AIM: This study aimed to compare the fracture resistance and fracture modes of ceramic onlay restorations with or without fiber posts in endodontically treated premolars. MATERIAL AND METHODS: Fifty extracted human premolars with similar anatomic features were used in this study. Four groups (n = 10) were treated endodontically. Onlay cavities extended to the buccal and palatal cusps and reached out the endodontic accesses were prepared. Ceramic onlay restorations with or without fiber posts were categorized as Group CO (ceramic onlays without posts), Group COQF (ceramic onlays and quartz fiber posts), and Group COGF (ceramic onlays and glass fiber posts). Positive control group was left as non-restored (Group NR). Ten intact teeth were stored as negative control group (Group IT). Fracture resistance was measured using a universal load-testing machine applying compressive load at a crosshead speed of 1 mm min(-1) until fracture. Fracture resistance and modes were evaluated statistically. RESULTS: Ceramic onlay restorations (Groups CO, COQF, COGF) increased the fracture resistance significantly, when compared with non-restored teeth (P < 0.05). However, no significant differences were found in the groups with fiber posts in terms of fracture resistance (P > 0.05). Negative control group (IT) had significantly higher fracture resistance than all others (P < 0.05). Fracture types had significant differences among the groups (P < 0.01). CONCLUSIONS: Within the limitations of this ex-vivo study, partial coverage with ceramic onlays resulted in a significant improvement of the fracture resistance of endodontically treated premolars. However, insertion of glass or quartz fibers did not increase the fracture resistance significantly.

Ultrasonically Activated Irrigation to Remove Calcium Hydroxide from Apical Third of Human Root Canal System: A Systematic Review of In Vitro Studies.

INTRODUCTION: The aim of this systematic review was to summarize the outcomes of in vitro studies comparing ultrasonically activated irrigation versus other irrigation techniques for removing calcium hydroxide (Ca[OH]2) from the apical third of root canals. METHODS: The research question was developed according to the PICO strategy. A comprehensive literature search was performed. The Medline, Embase, and TRIP electronic databases were searched. A hand search of the reference lists of identified articles was performed to isolate relevant articles. Two reviewers critically assessed the studies against our inclusion and exclusion criteria. Evaluation of the risk of bias of the studies was performed independently by the 2 reviewers. RESULTS: After study selection, 62 were assessed for eligibility. Of these, 9 met the inclusion criteria and were included in the systematic review. Because considerable heterogeneity was found in the methodologies, it was not possible to combine the results of studies in a meta-analysis. Ultrasonically activated irrigation was found to be superior to syringe irrigation and apical negative pressure irrigation, but insufficient evidence was found to indicate its superiority over the other irrigation techniques such as sonically activated irrigation, the Self-Adjusting File, (ReDent-Nova, Ra'anana, Israel) and the RinsEndo, (Dürr Dental, Bietigheim, Germany). CONCLUSIONS: On the basis of available evidence, we determined the effectiveness of ultrasonically activated irrigation compared with syringe and apical negative pressure irrigation. Because of the small sample sizes, low number of included studies, and limitations, further research is needed to confirm our results.

Fracture Resistance of Roots Restored with Four Different Fiber-Reinforced Composite Posts.

OBJECTIVE: The aim of this study was to compare the resistance to vertical root fracture of root-filled teeth restored with four different fiber-reinforced composite (FRC) post systems and two types of dual-cured resin luting agents. MATERIALS AND METHODS: Ninety extracted human maxillary central incisors were selected and decoronated to obtain a standardized root length of 14 mm. After root canal obturation, post spaces were prepared to a depth of 10 mm with a No. 3 post drill. The specimens (n = 80) were divided into two groups (n = 40) according to the resin luting agents used: group 1, Variolink II + ExciTE DSC; group 2, RelyX Unicem. These groups were subdivided into four subgroups (n = 10) and restored with one of the following post systems: (a) DT Light, (b) DT Light SL, (c) FRC Postec and (d) Everstick, while the remaining 10 teeth served as controls. The roots were subjected to axial compressive loading using a 2.2-mm-diameter metal sphere in a universal testing machine (0.5 mm/min). A factorial experiment with a single control group (analysis of variance) was used to test the resistance of the specimens. RESULTS: Groups 2a (DT Light + RelyX Unicem; 398.5 N) and 1b (DT Light SL + Variolink II + ExciTE DSC; 431.1 N) had significantly higher resistance to fracture than the control group (334.1 N; p < 0.05). DT Light SL and FRC Postec Plus were more resistant to fracture when Variolink II was used as the luting cement. DT Light and Everstick had higher fracture resistance when they were luted with RelyX Unicem (p < 0.05). CONCLUSION: The results of this study indicate that the use of quartz fiber posts (DT Light and DT Light SL) with an adhesive luting cement in root-filled teeth may reinforce the root to some extent.

Determination of canal orifice co-ordinates and MB2 incidence of maxillary first molars in a Turkish sub-population.

OBJECTIVES: To measure the co-ordinates of the root canal orifices and to determine the incidence of mesiobuccal-2 (MB2) in maxillary first molars in a Turkish sub-population. MATERIALS AND METHODS: Standard digital photographs were taken under a stereomicroscope from the occlusal aspect of each tooth (n = 176) before and after crown removal. Canal orifices were negotiated under moderate magnification using dental loupes. The coordinates of the orifices and the distances of each from the central fossa were measured by using geographic software. Intensity maps of the orifice locations were created by using the co-ordinates of all canal orifices. A representative map was drawn using the mean values of orifice locations and access projection area. RESULTS: In the right maxillary first molars, the mean values for the (X, Y) co-ordinates were (0.67, 2.68) for mesiobuccal-1 (MB1), (0.81, 0.84) for MB2, (-1.12, 1.26) for distobuccal-1 (D1), (-0.89, 0.23) for distobuccal-2 (D2) and (0, -2.50) for palatinal (P); the corresponding mean values in the left maxillary first molars were (-0.78, 2.56), (-0.98, 0.90), (0.99, 1.18), (0.69, 0.78) and (0.00, -2.53), respectively. The average MB1-MB2 distance was 1.97 mm. Distobuccalcanal orifices were localized at the distal side of the center in 98.3% of teeth. The incidence of MB2 was 46.02%. CONCLUSIONS: The distobuccal canal orifice is mostly located on the distal side of the central fossa. Thus, it should be considered that the access cavity of the maxillary molars may not be always limited mesially. The incidence of MB2 in this sub-population was 46.02%, which is of great importance clinically.

Experimental evaluation of cyclic fatigue resistance of four different nickel-titanium instruments after immersion in sodium hypochlorite and/or sterilization

NiTi instruments have a high risk of separation due to torsional or flexural fatigue (cyclic fatigue). Chemomechanical preparation, cleaning procedures, chemical disinfection and sterilization cause the corrosion of endodontic instruments that may weaken the fracture resistance of the instruments. Objective To assess the effects of NaOCl immersion and autoclave sterilization on the cyclic fatigue resistance of ProFile, FlexMaster, Mtwo and TwistedFiles NiTi instruments (tip size 25, 0.06 taper, n=160). Material and Methods The instruments (n=10 for each subgroup) were dynamically immersed in NaOCl; immersed in NaOCl and sterilized in one autoclave cycle; 5 cycles immersed in NaOCl and sterilized in autoclave and not immersed in NaOCl and not sterilized (control group). Dynamic cyclic fatigue resistance was tested. The number of cycles to failure (NCF) were statistically analyzed (P<0.05). Results Kruskall-Wallis test indicated significant differences among the tested instruments in terms of NCF (P=0.000). The mean NCF of Mtwo (556.75) was higher than that of the Twisted File, Flexmaster and ProFile, 483.1, 376.12, 365.25, respectively. NaOCl immersion and autoclave sterilization have no effect on the NCF values of the tested instruments (P>.05). Conclusions Cyclic fatigue resistance of the tested NiTi instruments cannot be adversely affected by NaOCl immersion and autoclave sterilization. Production process (TwistedFiles) or design (Twisted Files, FlexMaster, Mtwo and ProFile) of the instruments can influence their cyclic fatigue resistance. .

Experimental evaluation of cyclic fatigue resistance of four different nickel-titanium instruments after immersion in sodium hypochlorite and/or sterilization.

NiTi instruments have a high risk of separation due to torsional or flexural fatigue (cyclic fatigue). Chemomechanical preparation, cleaning procedures, chemical disinfection and sterilization cause the corrosion of endodontic instruments that may weaken the fracture resistance of the instruments. Objective To assess the effects of NaOCl immersion and autoclave sterilization on the cyclic fatigue resistance of ProFile, FlexMaster, Mtwo and TwistedFiles NiTi instruments (tip size 25, 0.06 taper, n=160). Material and Methods The instruments (n=10 for each subgroup) were dynamically immersed in NaOCl; immersed in NaOCl and sterilized in one autoclave cycle; 5 cycles immersed in NaOCl and sterilized in autoclave and not immersed in NaOCl and not sterilized (control group). Dynamic cyclic fatigue resistance was tested. The number of cycles to failure (NCF) were statistically analyzed (P<0.05). Results Kruskall-Wallis test indicated significant differences among the tested instruments in terms of NCF (P=0.000). The mean NCF of Mtwo (556.75) was higher than that of the Twisted File, Flexmaster and ProFile, 483.1, 376.12, 365.25, respectively. NaOCl immersion and autoclave sterilization have no effect on the NCF values of the tested instruments (P>.05). Conclusions Cyclic fatigue resistance of the tested NiTi instruments cannot be adversely affected by NaOCl immersion and autoclave sterilization. Production process (TwistedFiles) or design (Twisted Files, FlexMaster, Mtwo and ProFile) of the instruments can influence their cyclic fatigue resistance.

Survey of attitudes, materials and methods preferred in root canal therapy by general dental practice in Turkey: Part 1.

OBJECTIVE: To gather information on the materials and methods employed in root canal treatment by dentists in Turkey. METHODS: A questionnaire was distributed to 1,527 dentists who attended the Turkish Dental Association Congress. Respondents were asked to choose one or more suitable answers for the questions. Data was gathered for demographic and professional information regarding stages, materials, and methods commonly used in endodontic therapy. The collected data was analyzed using the statistical package SPSS. Descriptive statistics were given as frequencies (n) and percent (%). Chi-square (χ(2)) test was used to investigate the influence of gender and the years of professional activity for the materials and techniques employed. RESULTS: The response rate was 49%. A total of 97% of respondents were working in a general dental practice. Of respondents, 44% were using an agent containing arsenic or aldehyde. Only 5.1% of the respondents preferred the rubber dam isolation method. Sodium hypochlorite was the most popular choice (73%) as a root canal irrigation solution. Calcium hydroxide was the most commonly used medicament (53%). Most of the practitioners (77%) preferred radiographs for working-length determination. Root canal preparation done solely with K-Files or in combination with other instruments was preferred by 73.1% of the respondents. Ni-Ti hand or rotary files were used by 79.7% of the practitioners. Polymer based root canal sealers were the sealers most frequently chosen (48.4%). The majority of the respondents (66.2%) preferred cold lateral condensation as an obturation technique. Gender affected the preference of intracanal medicament, periapical radiographs for working-length determination, root canal instrument, root canal sealers, and root canal obturation technique (P<.05). Years of professional experience affected the preference of devitalizing agents, irrigation solutions, intracanal medicament, root canal instrument, root canal sealer, and root canal obturation technique (P<.05). CONCLUSIONS: It is clear that a number of dentists, irrespective of the time elapsed since their graduation, relied on techniques, and used products and materials that are currently favoured by expert opinion. Unfortunately, it was noted that some practitioners are still using arsenic- and aldehyde-containing devitalizing agents, and most did not use rubber dam as an isolation method.

Quality of root canal fillings performed by undergraduate dental students.

OBJECTIVES: The purpose of this study was to evaluate the radiographic quality of root canal fillings performed by first and second clinical year dental students at the Faculty of Dentistry in Süleyman Demirel University, Turkey. METHODS: The technical quality of 833 root canal fillings was evaluated by three examiners according to the density of the filling and the distance between the end of the filling and the radiographic apex. A root canal with acceptable filling length and homogeneous root filling was defined as being good quality endodontic work (GQEW). A treated tooth was defined as having good quality endodontic work tooth (GQEW-T) when all its canals had a GQEW rating. RESULTS: A Chi-square (χ(2)) test at the 0.05 significance level was used for the statistical analysis of the data. Of a total of 833 root canals, 662 (79.47%) root fillings were classed as GQEW. Two hundred fifty canals (73.4%) (135 teeth) treated by first clinical year dental students were defined as GQEW-T while 412 canals (204 teeth) (73.9%) treated by second clinical year dental students were defined as GQEW-T (P>.05). Most of the GQEW-T were defined in anterior teeth (90.1%), whereas the fewest were in molar teeth (46.6%) for both first and second clinical year dental students (P<.001). CONCLUSIONS: The quality of root canal fillings in anterior teeth performed by undergraduate dental students in Isparta, Turkey was satisfactory. However, to improve the success with molar teeth, education about newer techniques and instruments must be incorporated into the preclinical and clinical curriculum.

Corono-apical leakage of various root filling materials using two different penetration models--a 3-month study.

The purpose of this study was to analyze the sealing ability of various filling combinations in a 90 days period using fluid transport and glucose penetration models. Premolars (n = 108) were filled with either gutta-percha (groups 1-4) or Resilon (groups 5-8) core materials combined with AH Plus (groups 1, 3, 5, 7) or Epiphany (groups 2, 4, 6, 8) sealers by using cold lateral compaction (groups 1, 2, groups 5, 6) or System B with Obtura II (groups 3, 4, groups 7, 8). The sealing ability of each sample was evaluated through glucose and fluid penetration models. Penetration values of 90 days were statistically analyzed with three-way analysis of variance (ANOVA)and Duncan's Multiple Range tests (p < 0.05). No significant differences were found among the penetration values when the fluid filtration model was used (p > 0.05). On the contrary, statistically significant differences were obtained among the groups with the glucose penetration model (p < 0.05). AH Plus/Resilon/cold lateral compaction group had better sealing ability than the other combinations tested with the glucose penetration model.

Influence of custom-made mouth guards on strength, speed and anaerobic performance of taekwondo athletes.

The purpose of this study was to test the influence of custom-made mouth guards on strength and anaerobic performance of taekwondo athletes. The study included 21 (11 male and 10 female) trained subjects participating in taekwondo. Anaerobic power and anaerobic capacity, isokinetic quadriceps and hamstring strength, handgrip strength, isometric lower extremity and back strength, 20 m sprint time, squat and counter movement jumping height were measured in two randomized conditions: with or without custom-made (CM) mouth guards. No significant differences were observed between the two conditions (with or without CM mouth guards) in 20 m sprint time, jumping tests, handgrip strength, isometric leg or back strength. On the other hand, peak power and average power in Wingate Anaerobic Test and Hamstring Isokinetic Peak Torque significantly increased as a result of wearing mouth guard (P < 0.05). In conclusion, we can suggest that taekwondo athletes can use CM mouth guards without any negative effects on their strength and anaerobic performance.

Evaluation of the sealing ability of gutta-percha and thermoplastic synthetic polymer-based systems along the root canals through the glucose penetration model.

OBJECTIVE: To compare the sealing ability of gutta-percha and thermoplastic synthetic polymer-based systems along the root canals using a recently introduced glucose penetration model. STUDY DESIGN: Premolars (n = 156) instrumented to an apical size of .06/40 were divided into 12 experimental and 2 control groups. The root canals were filled with either gutta-percha (groups 1-6) or Resilon (groups 7-12) core materials combined with AH Plus (groups 1, 4, 7, 0), Ketac Endo (groups 1, 5, 8, 11), or Epiphany (groups 2, 6, 9, 12), using cold lateral compaction (groups 1-3, 7-9) or System B with Obtura II (groups 4-6, 10-12). The leaked glucose concentration was measured spectrophotometrically at 1, 8, 15, 22, and 30 days. Percentage leaking of each group was also calculated. Data were recorded as mmol/L and statistically analyzed with Kruskal-Wallis and Mann-Whitney U tests (P = .05). RESULTS: Throughout the experimental period Resilon/Ketac-Endo/cold lateral compaction (group 8) showed the highest mean cumulative glucose penetration (mmol/L) (17.27 +/- 10.32), whereas Resilon/AH Plus/cold lateral compaction (group 7) had the least (3.36 +/- 4.65) (P < .05). At the 30(th) day, the least leaking percentage was observed in gutta-percha, Epiphany/cold lateral compaction (group 3). Glucose penetration was affected by the obturation technique in some groups. Ketac-Endo either with gutta-percha (group 2) or Resilon (group 8) indicated significantly less glucose penetration in warm technique, whereas gutta-percha/Epiphany (group 3) had significantly less glucose penetration in cold technique (P < .05). CONCLUSIONS: All material/technique combinations allowed glucose penetration. Gutta-percha/AH Plus combinations allowed similar patterns of glucose penetration to Resilon/Epiphany combinations.

Do custom-made mouth guards have negative effects on aerobic performance capacity of athletes?

Mouth guards are considered an essential part of equipment for athletes participating in contact sports. The purpose of this study was to evaluate the effect of custom-made mouth guards on the ventilatory gas exchange effects of taekwondo athletes. The subjects were 22 elite athletes aged between 14 and 17 years. To determine the effect of mouth guard use during exercise, oxygen consumption (VO(2)) was measured with a portable gas analysis system while an exercise tolerance test with a shuttle run test protocol was performed. Values with and without mouth guard were compared. Wilcoxon ranks test was used for the statistical analysis. The results show that wearing mouth guards has no significant effect on maximal oxygen uptake (VO(2max)), minute ventilation (VE), tidal volume (VT) and respiratory exchange ratio (RER) while performing maximal exercise (P > 0.05). In conclusion, taekwondo athletes can use custom-made mouth guards without negative effects on their aerobic performance capacity.

Dental trauma incidence and mouthguard use in elite athletes in Turkey.

Contact sports may lead to dental trauma, which often can be reduced with appropriate preventive measures. While numerous studies exist on this topic for several countries throughout the world, there is a lack of comprehensive descriptive studies in Turkey. The purpose of this study was to investigate the incidence and type of dental injuries associated with three different sports among Turkish elite athletes, who do not contact (volleyball), contact directly (taekwondo) or indirectly (handball) with competition rivals. Additionally, awareness and use of mouthguards were also compared. Thus, during the 2003 and 2004 Turkish National Championships in three sports, 50 taekwondo, 62 handball and 50 volleyball male athletes were interviewed by questionnaire. Results showed that taekwondo and handball athletes experienced significantly more dental trauma than volleyball athletes (P < 0.05). Twelve of the taekwondo (24%), 16 of the handball (26%) and four of the volleyball athletes (8%) experienced at least one type of dental injury. Awareness of mouthguards as a preventive measure against dental trauma was significantly higher among taekwondo and handball athletes (P < 0.05), although a very small percentage in either of these sports actually wore a mouthguard (10 and 0%, respectively). Trauma incidence between direct contact with rival competitors and indirect contact with rival competitors was not significantly different. The incidence of dental trauma in contact sports shows that the awareness and use of mouthguards must be intensified. Mouthguard use should be made compulsory, especially in those sports with high risk for dental trauma.