Intact Teeth Research Articles

Influence of Different Mouthwashes on the Efficacy of Fluoridated Dentifrices in Prevention of Enamel Erosion: An In Vitro Study.

The purpose of the current study was to evaluate the impact of three various mouthwashes on the effectiveness of fluoride dentifrices in preventing enamel erosion. A total of 120 sound intact human premolar teeth which were extracted for orthodontic treatment were selected for the study. A 3 × 3 mm window section was positioned in the middle of the coronal surface of the tooth in order to define the study area. Each sample was placed in a solution of 1% citric acid (pH 3.5) for 10 minutes in order to produce an eroded surface. All samples were divided into two main groups (60 samples each) as follows: Group A for sodium fluoride dentifrices and group B for stannous fluoride dentifrices, again it is subdivided into: CHX: Chlohex ADS®, EO: Listerine®, CPC: Colgate® Plax (20 samples in each subgroup). After that, samples underwent the pH cycling model for 5 days. Samples were examined for surface loss using a scanning electron microscope. In sodium fluoride dentifrices group, before intervention, the surface loss was 3.12 ± 1.03 in CHX group, 3.08 ± 1.20 in EO group, and 3.09 ± 0.96 in CPC group. After intervention, the less surface loss found with CHX group (2.18 ± 0.84), followed by CPC (2.34 ± 0.74) and EO group (2.46 ± 0.97). In stannous fluoride dentifrices group, before intervention, the surface loss in CHX group was 3.26 ± 1.19, in EO group, it was 3.18 ± 1.31, and in CPC group, it was 3.22 ± 1.06. After intervention, the less surface loss found with CHX: group (1.90 ± 0.54), followed by CPC (2.24 ± 0.28) and EO group (2.38 ± 0.20). The present study concluded that the fluoride dentifrices' preventive effects against tooth surface loss were unaffected by a different mouthwashes with varying compositions and major constituents. In terms of erosion, fluoridated toothpaste containing stannous fluoride was found to provide better surface loss protection than sodium fluoride. Primary prevention and the eradication of contributing causes are the greatest strategies for preventing erosion. Simultaneously, antibacterial agent in the mouthwashes may help in enhancing the effect of fluoride in the enamel, owing to their high affinity for teeth structures. Therefore, in addition to cause-related treatment, further efforts to reduce tooth tissue loss are also necessary.

Spectrophotometric Analysis of Color Stability Induced by Various Calcium Silicate Cements in Full Pulpotomy of Permanent Molars: Theracal PT, Biodentine, and ProRoot MTA

AimThe objective of this study was to assess the color stability induced by Theracal PT, Biodentine, and ProRoot MTA in teeth subjected to full pulpotomy, over a span of 6 months. Materials and MethodsThe study employed a total of 48 freshly extracted intact human third molar teeth. Samples were randomly assigned into four groups (n = 12). All teeth, with the exception of the control group, underwent endodontic access. All materials were mixed in accordance with the manufacturer's guidelines and applied at a thickness of 3 mm at the orifice level before they set. The study groups were negative control (was not prepared), positive control (ProRootMTA), Biodentine, and Theracal PT. Glass ionomer and composite resin material was applied to the cavities. The color measurements were performed using the VITA Easy Shade spectrophotometer. All measurements were repeated 3 times in the determined area on the middle buccal surface of the tooth at baseline that (T0); after access preparation and material placement and setting) and then subsequently at 7 (T1), 30 (T2), 90 (T3), and T4 (180) days later. Data were statistically analyzed by using Kruskal-Wallis H at a confidence level of 95% (P < .05). ResultsCompared with the negative control group, Biodentine and Theracal PT showed color stability (ΔE ≤ 3.7). The teeth treated with MTA showed clinically observable discoloration (ΔE ≥ 3.7) at T0, T1, T2, T3, and T4 intervals. At all-time intervals, the MTA group induced more discoloration than Biodentine and Theracal PT (P < .05). ConclusionsTheracal PT and Biodentine caused least discoloration compared to PMTA even 6 months after its application in teeth undergoing pulpotomy, thereby offering clinicians a reliable alternative for use in the esthetic zone.

Effect of photobiomodulation therapy on TGF-β release from dentin, migration and viability of dental pulp stem cells in regenerative endodontics treatment: An ex vivo study

Background and aimRegenerative endodontic procedures (REPs) are oriented by the principles of tissue engineering, incorporating dental pulp stem cells (DPSC), crucial growth factors like Transforming growth factor-β (TGF-β1), and scaffolds to facilitate the regeneration of dental pulp tissues. The present study aimed to investigate the effect of photobiomodulation (PBM) therapy, using an 808 nm diode laser on cellular modulation mechanisms in REPs. Method and materialA total of 108 human dentin discs obtained from intact single root teeth were randomly assigned into six groups (n = 8): 1. Positive control (EDTA), 2. PBM-1 (3 J/cm2), 3. PBM-2 (5 J/cm2), 4. EDTA+PBM-1, 5. EDTA+PBM-2, and 6. Negative control (NaOCl). Then, an extract solution was prepared from each disc and the concentration of released TGF-β1 from the discs was measured using enzyme-linked immunosorbent assay (ELISA). Moreover, the extract solution was added to DPSC culture medium to evaluate cell viability and migration through MTT assay and scratch test, respectively. ResultThe group exposed to PBM-1 showed the highest cell viability, while treatment with EDTA and EDTA+PBM-2 decreased cellular viability. Also, the PBM-treated groups showed significantly higher release of TGF-β1 compared to the negative control. EDTA and EDTA+PBM-1 showed the highest release among all the groups. No significant difference was found between EDTA and EDTA+PBM-1, as well as between PBM-1 and PBM-2. Moreover, the PBM-1 group exhibited the highest migration after 24 h, which was significantly greater than other groups, except for the PBM-2 group. ConclusionAccording to the obtained data, 808 nm mediated-PBM (3 J/cm2), both independently and in conjunction with EDTA, enhanced the release of TGF-β1 from dentin and improved cell viability and migration of DPSCs. It seems that, PBM under the specific parameters employed in this study, could be an effective adjunctive therapy in REPs.

Quantity and diameter of dentinal tubules of human teeth and teeth of experimental animals according to scanning electron microscopy data

Insight into the interrelation between the structure and mechanical properties of dentin of a tooth is crucial for prevention and treatment of oral cavity diseases. The study of the structure of dental dentin is important for understanding the pathogenetic mechanisms of the spread of cariogenic microflora in progressive dental caries to the pulp and periodontium, as well as for the interpretation of the results of studies of dental dentin-adhesive materials. The in vitro research presented here involved the examination of coronal dentin in 46 intact teeth from rats, cats, dogs, and humans at various distances from the pulp chamber, with a focus on the quantity and diameter of dentinal tubules. The calculations were based on the analysis of 155 scanning electron microscope photographs of the enamel surface and pulp chamber wall. The researchers calculated the quantity and diameter of dentinal tubules per unit area, which they measured at various distances from the pulp chamber. It was found that dentinal tubules are the widest near the pulp chamber wall, where the average diameter ranged from 1.7 to 2.8 µm. The highest values were found in premolars of young humans and the lowest - in the incisors of rats. In the middle portion of the dentin, the diameter of dentinal tubules ranged from 1.0 to 13.3 µm, while at the periphery, it was 0.6–0.9 µm. The highest density of dentinal tubules per unit area was found closest to the pulp horn, and the lowest was in the enamel region. Near the pulp chamber wall, the average density of dentinal tubules ranged from 50 000 to 90 000/mm², in the middle of the dentin, it ranged from 37 000 to 50 000/mm², and at the periphery, it ranged from 10 000 to 25 000/mm². All examined teeth exhibited straight dentinal tubules, except for the rats’ incisors, which showed local irregularities. A comparison was made based on the quantity and width of dentinal tubules in the examined animals and humans.

DENSITY ANALYSIS OF HARD TISSUES OF CERVICAL REGION OF PERMANENT TEETH OF DIFFERENT GROUPS

Abstract. In the practice of clinical and experimental dentistry, numerous studies are devoted to the study of the dynamics of jaw bone tissue density in the age-related aspect and in various pathological conditions. At the same time, the determination of the mineral density of the hard tissues of the teeth is of practical use only in isolated cases.The aim of the study: fi nding out the features of the ratio of indicators of hard tissue density of permanent teeth of diff erent groups in the cervical region.Material and methods. In order to determine the density of the hard tissues of cervical region, radiographs of 320 intact permanent teeth (n=10 for each permanent dentition tooth), made on a Siemens dental radiovisiography device with Trophy Radiology software, were processed. The images were processed in the VixWin Pro program. The unit of measurement of tissue density is the conventional grayscale value (GSV). Tissue density in the cervical region was determined separately for enamel, cementum, and dentin, the diff erence between the established indicators was presented as a percentage.Results of the study. A signifi cant diff erence in the density of enamel, dentin and cementum of permanent teeth was established. It was found that in the cervical region of incisors, dentin has the highest density, cement has the lowest density; in canines, dentin has the highest density, enamel has the lowest density; in premolars, dentin has the highest density, cementum has the lowest density; in molars, enamel has the highest density, cementum has the lowest density. The enamel and dentin density indicators are the lowest in incisors, then gradually increase in canines and premolars, and reach the maximum value in molars. Cement density indicators are also the lowest in incisors, slightly higher in premolars, still increase in canines and reach the maximum value in molars.Conclusions. When using radiological methods to research the condition of the hard tissues of the teeth, it is the radiological biomarkers that can become an eff ective tool for studying the susceptibility or resistance of teeth to pathological lesions, in the cervical region in particular.

Hard tissue density of permanent teeth as a radiometric biomarker of their quality

Background. The use of radiographic methods for examining patients with the ability to determine the density of examined tissues opens up wide opportunities for individually predicting damage to hard tissues of teeth, as well as determining risk groups for the development of their pathology at early stages, which requires a detailed study of the mineral density indicators of hard tissues of teeth of different groups within the norm, taking into account their age, sex, ethnic, and other characteristics. The aim of the study was to determine the density indicators of hard tissues of permanent teeth of different groups in the cervical area and compare them. Material and Methods. The density of hard tissues was determined by analyzing radiographs of 320 intact permanent teeth of 10 patients. Radiographs were made using a Siemens Sirona (XIOS XG Supreme, Germany) dental radiography unit with Trophy Radiologie software (version 7.0, Slovakia). The images were processed using Gendex VixWin Pro software (version 3.5, USA). The density was measured in Conditional Unit of Grayness (CUG). The results were presented as Me (25%; 75%), where Me represents the median, 25% denotes the 25th percentile (first quartile), and 75% denotes the 75th percentile (third quartile). Results. Incisors, canines, and premolars exhibited the highest density in the dentin area; the lowest density was observed in incisors and premolars for cementum and in canines for enamel. In molars, enamel had the highest density, while cementum had the lowest. Significant differences in enamel density were observed among incisors and premolars, incisors and molars, canines and premolars, canines and molars, and premolars and molars. Significant differences in dentin density were found among incisors and canines, incisors and premolars, incisors and molars, canines and premolars, and canines and molars. Significant differences in cementum density were observed among incisors and canines, incisors and premolars, incisors and molars, canines and premolars, and premolars and molars. Conclusion. The density indicators of enamel, dentin, and cementum established for groups of permanent incisors, canines, premolars, and molars are different for different tooth groups with characteristic density patterns. Keywords: enamel, dentin, cementum, incisors, canines, premolars, molars.

The Effect Of Er,Cr:YSGG Laser Conditioning on Dentin Bond Strength and Nanoleakage of Universal Adhesive Systems: An In Vitro Study.

To investigate the effect of erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser conditioning on dentin bond strength and nanoleakage of different universal and self-etch adhesives. A total of 84 intact human third molar teeth were cut at the dentin level, and half of them were laser conditioned. The specimens were divided into three groups; two different universal resins and one self-etch adhesive resin were applied and composite resin restorations were created. For the microtensile bond strength (µTBS) test, 20 microspecimens were prepared from the laser and control group of each adhesive (n = 20) and tested with a universal device. For nanoleakage observation, 10 specimens were prepared from each group (n = 10) and stored in silver nitrate solution, and then the amount of nanoleakage was analyzed by field emission scanning electron microscopy (FESEM). Data were analyzed with two-way ANOVA, Tukey's honestly significant difference, and chi-square tests. The mean dentin bond strength of all adhesives in the laser groups was found to be statistically significantly lower than those of the control groups (P < .05). No difference was found between the mean bond strength of the adhesives in the laser and control groups (P > .05). Higher nanoleakage was observed in all adhesives in the laser groups compared to the control groups (P < .05). Irradiation of the dentin surface with Er,Cr:YSGG could adversely affect the µTBS and nanoleakage, likely by affecting the structure of the hybrid layer.

Transdentinal cytotoxicity of resin luting cements using the bovine and human dentin barrier

Based upon ethical questions and because of the difficulty of obtaining intact human teeth, researchers have used bovine teeth to assess the physical and mechanical properties of different dental materials. However, data from transdentinal cytotoxicity tests showing that the bovine dentin barrier is similar to the human dentin barrier is lacking. The purpose of this in vitro study was to evaluate whether the bovine dentin barrier produces similar results to those obtained when the human dentin barrier is used to assess the transdentinal cytotoxicity of resin luting cements. The number and diameter of dentinal tubules present in the human dentin barrier and bovine dentin barrier were evaluated and assessed with a t test (α=.05). After inserting the standardized dentin barriers into artificial pulp chambers, murine dental papilla-derived cells (MDPC-23) were seeded on the pulpal surface of the specimens, and the luting cements were applied to their occlusal surfaces. Then, the following groups were established for both human and bovine dentin barriers: no treatment (negative control); Single Bond Universal; RelyX Luting 2; RelyX U200; and RelyX Ultimate. After 24 hours, the viability (alamarBlue) and morphology (scanning electron microscopy) of the cells were evaluated with a 2-way analysis of variance and the Tukey honest significance test (α=.05). Dentinal tubules with larger diameters were observed in bovine dentin (P<.05), but the number of tubules was similar (P>.05). A reduction in viability and notable changes in the morphology of MDPC-23 cells occurred in the Single Bond Universal and RelyX Luting 2 groups in comparison with the negative control (P<.05). The RelyX U200 and RelyX Ultimate groups were statistically similar to the negative control (P>.05). No difference was found in cytotoxicity when the same luting cement was applied on human or bovine dentin barriers (P>.05). For transdentinal cytotoxicity tests of resin luting cements, the bovine dentin barrier proved similar results to the human dentin barrier.

Options for Access Cavity Designs of Mandibular Incisors: Mechanical Aspects from Finite Element Study

IntroductionThis study investigated different access cavity designs of mandibular anteriors in terms of their effect on the biomechanical behavior and longevity using finite element analysis (FEA). MethodsA 3-dimensional model of a mandibular incisor was created for FEA. After validating the intact tooth (IT) model, 4 experimental models were developed (traditional lingual access cavity [TLA], facial access cavity [FAC], incisal access cavity [ICA], and cervical access cavity [CVA]). Cyclic loading was simulated, and the number of cycles until failure (NCF) was compared to the IT model. Stress distribution patterns, maximum von Mises stresses (vMSs), and maximum principal stresses (MPSs) were analyzed mathematically. The safety factor was also calculated and demonstrated. ResultsThe maximum vMS registered on the IT model was 134.16 MPa. The FCA and the CVA provided the highest NCF (193.7% compared with the IT model) followed by ICA (58.2%) and TLA (21.4%). The vM and MPS analysis revealed that the lingual surface is a primary stress channel, and the presence of an access cavity significantly weakens the tooth structure. Although the maximum vMS registered for the IT model was 134.16 MPa, the maximum vMS was 73.97 MPa for both the FCA and the CVA, 152.27 MPa for the ICA, and 173.63 MPa for the TLA. ConclusionsThe facial and cervical access cavity designs provided considerable reinforcement to the endodontically treated mandibular incisors. With advancements in esthetic restorative materials and endodontic instruments, facial access design could emerge as the new standard for access cavity preparation in mandibular incisors.

Common Temporization of Access Cavity and Pulp Spacers Practiced by Endodontists in Saudi Arabia: A Cross-sectional Study

Background: Temporary restorations are necessary for preventing coronal leakage during and after treatment completion and must provide an effective barrier against salivary contamination of the root canal system. Endodontic spacers also help remove temporary restoration by avoiding the chances of unwanted intact tooth structure loss and perforation on the floor of the pulp chamber and prevent temporary restorative materials entrapment into the root canals resulting in canal blockage. However, the cotton pellet placed between the temporary and the root canal orifice can compromise the coronal seal by the reduction in thickness of temporary restoration. Objective: The primary aim of this investigation was to determine the most common temporary restoration used during and after endodontic treatment. The secondary aim is to know the percent preference for restorations with double seal and the frequency of spacer used. Methods: Four hundred fifty online questionnaires comprising 15 (four demographic questions and eleven questions related to the study objective) were sent to endodontists in Saudi Arabia via WhatsApp and Twitter. Statistical significance was set at P&lt;0.05 when assessed using a chi-square test. Results: About 370 (82.22%) participants completed the survey. Glass ionomer cement (GIC) was most used as a temporary restoration among endodontists for both the anterior (53%) and posterior teeth (49.7%; P=0.001). In double seal, Cavit was most used as the temporary restoration, which was placed below the seal exposed orally 56.2% (P=0.001). GIC was most used as coronal seal material placed over Cavit in 71.9% of the participants (P=0.001). About 56.2% of the endodontists placed cotton pellets between visits but not after obturation (P=0.001). Polytetrafluoroethylene tape instead of cotton pellet was preferred by 30.3% of the participants (P=0.001). Conclusion: Glass ionomer cement (GIC) was most used as a temporary restoration. In double seal, GIC was most used as coronal seal material placed over Cavit. A pulp spacer was found to be the most commonly used between visits but not after obturation.

Results of the study of the mineralizing capacity and hydrogen indicator of the oral fluid in children taking into account the dental status and age

Caries is one of the most common dental diseases in children, which is characterized by enamel demineralization. The condition of the hard tissues of temporary and permanent teeth is influenced by a significant number of factors, including the oral fluid that is in direct contact with the teeth. The mineralizing ability of the oral fluid affects the state of the hard tissues of the teeth, that is, the acid resistance of the enamel, the decrease of which leads to demineralization with further progression of the carious process. The aim of the study was to study the indicators of the mineralizing potential and the pH of the oral fluid in children aged 7–12 years with caries of temporary and permanent teeth and to compare them with the indicators of children with intact teeth. The dental status of 223 children aged 7–12 years was studied (in each child, the condition of the hard tissues of the teeth was determined and the DMFT (Decayed, Missing and Filled Teeth) in the temporary bite, DMFT/dmft (Decayed, Missing and Filled Teeth) in the variable bite, dft (decayed and filled teeth) in the permanent bite index was calculated), mineralizing potential and pH of the oral fluid were calculated. Indicators were compared in children with and without caries. The course of caries of both temporary and permanent teeth in children occurs against the background of a decrease in pH and microcrystallization of oral fluid. This is especially noticeable in children who have affected permanent teeth. The caries rate of temporary and permanent teeth has inverse correlations with the pH and microcrystallization index of the oral fluid. The obtained data suggest the need for primary and secondary prevention, aimed at improving oral homeostasis indicators, planned remediation, which will make it possible to reduce the prevalence and intensity of caries in children, which will be the subject of our further research. Keywords: caries, intact teeth, pH of oral fluid, microcrystallization of oral fluid.

Assessment of the Impact of Adhesive and Wires Types on the Tensile Bond Strength of Fixed Lingual Retainers Used in Orthodontics: An In Vitro Study

Introduction: We aimed to assess the impact of adhesive and wires types on the tensile bond strength of fixed lingual retainers. Methods: A total of 160 intact bovine teeth were collected, cleaned, stored in 25% sodium hypochlorite, and randomly assigned to two groups based on the adhesive type: a two-step adhesive and a one-step adhesive. Each group was further divided into four subgroups based on the type of lingual retainer wire, which included (A) 8-strand braided stainless steel wire, (B) three-strand titanium retainer wire, (C) stainless steel chain, and (D) fiber-reinforced retainer. A tensile bond strength test was conducted using a universal testing machine at a controlled speed of 10 mm/min. Result: The 8-strand braided stainless steel wire and stainless steel chain bonded by one-step self-priming adhesive showed significantly higher tensile bond strength (P &lt; 0.001). The adhesive wire significantly affected the tensile bond strength (P &lt; 0.001). Conclusion: Within the limitations of this in vitro study, it can be concluded that stainless steel wire and chain bonded by one-step self-priming adhesive showed higher tensile bond strength.

Effect of Er,Cr:YSGG and Nd:YAG Lasers on Microleakage of Composite Resin Restorations Using Universal Adhesives

Background: Clinical long-term success of bonded restorations is depended to reduce marginal microleakage and the laser application with combination of new bonding systems may play positive role. The aim of this study was comparative evaluation of Er,Cr:YSGG and Nd:YAG lasers effect on microleakage of class V composite resin restorations using several universal adhesives. Methods: In this in vitro study, standard class V cavities were prepared on both lingual and buccal surfaces of 72 intact premolar teeth. For evaluation of microleakage, the cavities were divided into 9 groups according to conditioning method (n=15): G1: G-Premio Bond [GP]; G2: Scotchbond Universal Adhesive [SU]; G3: All-Bond Universal [AB]; G4: GP+Nd:YAG Laser; G5: SU+Nd:YAG Laser; G6: AB+Nd:YAG Laser; G7: GP+Er,Cr:YSGG Laser; G8: SU+Er,Cr:YSGG Laser; and G9: AB+Er,Cr:YSGG Laser. The cavities were filled with composite resin and then subjected to thermocycling, placed in methylene blue solutions, embedded in resin blocks and vertically cut in the bucco­lingual direction. The microleakage in occlusal and gingival margins was defined as linear penetration of methylene blue and determined with a stereomicroscope to assign microleakage scores using a four­point scale. Data were analyzed by using SPSS software and Kruskal-wallis and Mann-Whitney U tests. Results: Microleakage scores had statistically significant different before and after laser irradiation in dependent to the adhesive used (P&lt;0.05) but there were no significant different between Nd:YAG and ER,Cr:YSGG laser, also between different universal adhesives (GP, SU, AB). The results showed that total microleakage scores of occlusal margins had significant statistical different in comparison with gingival margins (P&lt;0.001). Conclusion: The results indicate that Nd:YAG and Er,Cr:YSGG lasers irradiation, after using the investigated universal adhesives, had a positive effect on reducing the microleakage of composite Class V restorations. The microleakage rate was shown to be independent of adhesives and lasers type used in this study.

The Effect of Different Percentages of Nano-bioactive Glass in the Synthesized CPP/ACP Paste on the Remineralization of Demineralized Enamel

Background: The preventive treatments of primary caries lesions are essential for preventing destructive damage to the tooth structure. One of the common treatments is the application of casein phosphopeptide-amorphous calcium phosphate (CCP/ACP) paste on the enamel surface. The aim of this study was to investigate the effect of different percentages of nano-bioactive glass (nBG) incorporation into synthesized CPP/ACP paste on the remineralization of demineralized enamel. Methods: In general, 24 extracted human intact premolar teeth were selected, and their crowns were removed for this purpose. Each crown was cut into two halves, and each half was considered as a sample. The samples were placed in a demineralizing solution at a pH rate of 4.6 for 8 hours, in artificial saliva for 1 hour, and again in a remineralizing solution at a pH rate of 7 for 15 hours. The pH cycling was performed for 14 days to demineralize the enamel surface. The samples were randomly divided into 3 groups (n=16), including G1 (without treatment), G2 (treated with synthesized CPP/ ACP paste containing 5% nanobioglass), and G3 (treated with synthesized CPP/ACP paste containing 10% nanobioglass). The paste was then placed directly on the surface of the demineralized enamel for 4 minutes (twice a day for 28 days). The samples were subjected to the Vickers microhardness test. Finally, data were analyzed using SPSS (version 19) and the analysis of variance and Tukey’s tests (α = 0.05). Results: There was a significant difference between microhardness values in G1 and G2, as well as G1 and G3 (P&lt;0.05). However, no statistically significant difference was observed between G2 and G3 (P&gt;0.05). Conclusions: The results showed adding bioactive glass into synthetic CPP/ACP paste increases enamel remineralization in spite of the percentage of bioactive glass incorporation.

Comparison of fracture resistance of posterior tooth restored with cention-n, zirconomer and universal composite restorative material: An in-vitro study

The aim of this study was to access and compare fracture resistance of tooth restored with Cention-N, Zirconomer and Filtek Z350 XT. Seventy five extracted maxillary premolar were divided into five groups; (Group I) Unprepared intact teeth, (Group II) Teeth with class II mesio-occluso-distal (MOD) cavity prepared and unrestored, (Group III) Teeth with class II MOD cavity prepared and restored with Zirconomer (Shofu Inc), (Group IV) Teeth with class II MOD cavity prepared and restored with Cention N, (Group V) Teeth with class II MOD cavity prepared and restored with Universal Composite Restorative Material (Filtek Z350 XT). Specimen was individually tested in a universal testing machine for facture resistance. Filtek Z350 XT showed statistically significant fracture resistance as compared to Group II, Group III and Group IV (P&amp;#60;0.001). Cention-N showed better fracture resistance than Zirconomer but didn’t vary statistically. All the test restorative material showed acceptable fracture resistance under load. Long term clinical evaluation is required to access their behavior intraorally.

The Use of Fiber-Reinforced Composites for Restoration of Endodontically Treated Teeth: A Review

This review summarized the most recently published literature pertaining to the use of fiber-reinforced composite (FRC) to restore endodontically treated teeth (ETT) and its influence on the mechanical behavior of restored teeth. In-depth¬ literature review in Google Scholar, ScienceDirect and PubMed was performed for these keywords: “fiber-reinforced composite”; “fiber post”; “endodontically treated”; “short fiber-reinforced composite”— only published full-text articles between 2009 and 2021 are included in this review. Fourteen articles were selected for this review. The studies concentrated on laboratory-based research conducted on human and bovine extracted teeth with different restorative techniques. Fatigue survival and load to failure tests with assessment of survival rate and fracture strength values respectively, as well as fracture pattern analysis were done. We concluded that FRC materials have improved fracture strength of restored teeth compared to conventional composites using different restorative techniques, however not to the attained level of an intact natural tooth. In addition, authors recommend a better simulation of oral environment, such as dynamic fatigue-testing.

Comparison of conventional preparation with modified access preparation on fracture resistance of primary molars - A finite element analysis

ObjectiveTo investigate the influence of Conventional Straight (CS) line and Modified Straight (MS) line access preparations with various restorative materials on the fracture resistance of primary molars using Finite Element Analysis (FEA). MethodologyThree FEA models for each of the primary molars were divided into Group I- Intact tooth model; Group II- Model with CS outline and Group III- Model with MS outline. Based on the restorative material used, Group II and III were further subdivided into subgroup 1- GIC restoration, subgroup 2 – composite resin with GIC base and subgroup 3- Stainless Steel Crown (SSC). Each model was subjected to 5 different force loads directed at the occlusal surface. Maximal von Mises (VM) stresses calculated from stress distribution patterns. ResultThe maximum displacement, in all the models of primary molars were seen in GIC restored models in molars with both CS and MS access whereas the minimal displacement was seen in the SSC restored molars of MS group. ConclusionIn primary maxillary second molar and mandibular first and second molar with intact marginal ridges, the fracture resistance of tooth with MS outline restored with GIC base followed by Composite resin was comparable with the tooth restored with SSC and CS outline. Clinical outcomeBased on the results of this FEA analysis, composite restorations with MS outline would be appropriate for endodontically treated primary molars that have intact margins.

Effect of Delayed Endodontic Sealing with Dentin Biomodification on Fracture Resistance of Endodontically Treated Teeth

Aim: Endodontically treated teeth display altered tooth structure pertaining to various chemical irrigants and intracanal medicaments. To prevent the compromised adhesive bond, dentin biomodification is indicated. This study was designed to evaluate the influence of dentin biomodification on the fracture resistance of root canal-treated teeth following Delayed Endodontic Sealing (DES). Materials and Methods: In 50 maxillary central incisors, Class III cavities along with access cavities were prepared. The samples were randomly divided into five groups. Group 1: Intact teeth ( N = 10), Group 2: Immediate Endodontic Sealing (IES) ( N = 10); Group 3: DES after irrigation with 3% NaOCl ( N = 10); Group 4: DES with 2% chlorhexidine (CHX) as a biomodifier ( N = 10) and Group 5: DES with 5% grape seed extract (GSE) as a biomodifier ( N = 10). In Group 2 samples, composite restorations were done prior to irrigation with 3% sodium hypochlorite (NaOCl). Group 3 samples received root canal irrigation with 3% NaOCl for 1 min, etch and rinse procedure and composite restorations. In Groups 4 and 5, dentin biomodification was done prior to composite restorations. Teeth were subjected to fracture resistance tests. Statistical analysis was carried out employing analysis of variance (ANOVA) and Tukey’s post hoc tests ( p &lt; .05). Results: IES group demonstrated the highest fracture resistance, with a significant difference statistically ( p &lt; .05) when compared with the DES groups. DES modified with GSE resulted in significantly superior fracture resistance compared to DES only, but no statistical difference was present between the CHX and grape seed-treated DES groups. Conclusion: DES with the use of dentin biomodifiers such as 5% GSE and 2% CHX increased the fracture resistance of root canal-treated teeth compared to DES only.

The Effect of Remaining Coronal Tissue Height on the Fracture Strength of Over-Flared Endodontically Treated Central Incisors Restored Using a Multipost Approach.

This study aimed to examine the effect of remaining coronal tissue height on the fracture strength of over-flared endodontically treated central incisors restored with multiple prefabricated fiberglass posts using the multipost approach. A total of 40 human central maxillary incisors were examined in this study. The samples were assigned to five groups (n = 8) based on the height of the remaining coronal tissue: with no remaining coronal tissue, 1-mm coronal tissue height (CTH1), 2-mm coronal tissue height, 3-mm coronal tissue height (CTH3), and one intact tooth (IT) group. Following endodontic treatment of an over-flared canal, the postspace depth was 10 mm, and the residual dentin thickness was 1 mm. Two prefabricated fiberglass posts were cemented into the root canal, adopting a multipost approach. The static load was applied at 0.5 mm/min and 135° concerning the tooth's longitudinal axis until a fracture occurred. One-way analysis of variance and the post hoc Tukey's test were performed to analyze the data at a significance level of p < 0.05. The maximum fracture strength was recorded for IT (control group), while the minimum fracture strength was found for teeth with a coronal tissue height of 1 mm. The differences between IT group and other groups (p < 0.05), as well as the differences between the group with CTH3 and groups without coronal tissue and CTH1, were significant. In sum, an increase in the height of the remaining coronal tissue (≥3 mm) significantly increased the fracture strength of over-flared endodontically treated central incisors after restoration with prefabricated fiberglass posts by adopting a multipost approach.

Labral tooth loss in the carnivorous gastropod Acanthina monodon: Recovery capacity and incidence in the feeding process

The temporary loss of an animal feeding structure can often be replaced by a new one. During that replacement period, however, the animal can be limited in its ability to feed. The muricid gastropod Acanthina monodon can sometimes lose its labral tooth naturally; recovering the tooth will typically take between 14 and 21 days. Our studies show that the volume, length and area of the recovered tooth are equal to or greater than the characteristics of the original tooth. However, the recovered teeth were seen to grow differently and have different shapes than those of the original teeth. Moreover, less force was required to break the newly formed teeth, to an extent based on the shape of the new tooth. Although the toothless snails continued to feed in our study, the absence of the labral tooth had a negative impact on the size of attacked prey, although not on the number of prey attacked. Thus, the ingestion rate was lower in specimens with recovered teeth than in snails with the original intact teeth. Snails that lost the labral tooth also displayed alterations in the feeding process, including lower energy income and potential energetic repercussions, at least during the recovery period of the lost structure.