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INTRODUCTION Leptin is secreted as a peptide hormone from adipose tissues. The aim of this study was to evaluate the effects of leptin on reparative dentin formation and angiogenesis in the pulp tissue of teeth in vivo. METHODS Twenty-four 7-week-old male rats were anesthetized. Cavities were prepared in maxillary first molars. Pulp cappings were performed with collagen scaffold (Col) with a phosphate-buffered saline (PBS) vehicle (Col + PBS), leptin 1 μmol/L with Col (L1 + Col), or leptin 10 μmol/L with Col (L10 + Col). For the negative control group (no pulp capping), pulp capping was not performed. All cavities were sealed with resin-modified glass ionomer followed by a micro-computed tomographic scan, histologic examination, and immunohistochemical analysis. RESULTS The volume of newly formed mineralized tissue in the leptin group was significantly (P < .01) higher than that in the control group based on micro-computed tomographic analysis. In histologic examination, hard tissue formation was rarely shown in the no pulp capping and Col + PBS groups. However, significantly (P < .01) larger amounts of newly mineralized tissue deposition were observed in the leptin groups. In immunohistochemical analysis, reparative dentin and new vessels formed in the pulp cavity of the leptin groups. Vascular endothelial growth factor, dentin sialoprotein, and dentin sialophosphoprotein were expressed around the newly formed mineralized tissue area. CONCLUSIONS Leptin showed the ability to induce angiogenesis, odontogenic differentiation, and mineralization in exposed rat pulps. Leptin also exhibited favorable inflammatory responses in the pulp tissue. Not only osteodentin but also tubular dentin and new vessels were observed in the pulp cavity.

The aim of this study was to compare chemical properties and bioactivities of with mineral trioxide aggregate (MTA) and EndoSequence Root Repair Material (ERRM). After setting, surfaces of test materials were observed by scanning electron microscope (SEM). The pH and cell viability of materials were tested. Osteoblastic differentiation and alkaline phosphatase (ALP) activity were measured by quantitative real-time PCR and ALP staining. MTA showed spindle-shaped crystals while ERRM showed round-shaped crystals of various sizes. ERRM presented lower pH than MTA. Both materials showed good cell viabilities compared to the control. Expression levels of osteoblastic genes and ALP staining were increased significantly (p

An ideal root canal sealer creates a bacteria-resistant seal and exhibits antimicrobial activity, biocompatibility, and osteoconductivity. The aim of this study was to assess the effects of 3 root canal sealers on cell viability, inflammatory response, and osteogenic potential in MC3T3-E1 cells.AH Plus (Dentsply Caulk, Milford, DE), MTA Fillapex (Angelus Solucxoes Odontologicas, Londrina, Brazil), and EndoSequence BC (Brasseler, Savannah, GA) were mixed according to the manufacturer's instructions, and samples were prepared as extraction media (final dilution: 1/10). Lipopolysaccharide (LPS) (100 ng/mL) treatment was used to induce an inflammatory response in this study. Cell viability was evaluated using the Water soluble tetrazolium-1 (WST-1) assay. The levels of inflammatory mediators (interleukin 6 and tumor necrosis factor alpha) and osteogenic marker genes (ALP and OCN) were measured by reverse-transcription polymerase chain reaction and real-time polymerase chain reaction. Osteogenic potential was evaluated by alkaline phosphatase staining and alizarin red staining.Calcium silicate-based sealers such as MTA Fillapex and EndoSequence BC showed strong cell viability compared with AH Plus. AH Plus, MTA Fillapex, and EndoSequence BC decreased the levels of LPS-induced inflammatory mediators (P .05). The expression of osteogenic marker genes, alkaline phosphatase activity, and mineralized nodule formation decreased with LPS treatment. However, AH Plus and calcium silicate-based sealers increased the osteogenic potential reduced by LPS treatment (P .05).Calcium silicate-based sealers exhibit anti-inflammatory effects and induce osteogenic differentiation in MC3T3-E1 cells.

Objectives In recent in vitro study, it was reported that osteostatin (OST) has an odontogenic effect and synergistic effect with mineral trioxide aggregate (MTA) in human dental pulp cells. Therefore, the aim of this study was to evaluate whether OST has a synergistic effect with MTA on hard tissue formation in vivo. Materials and Methods Thirty-two maxillary molars of Spraque-Dawley rats were used in this study. An occlusal cavity was prepared and the exposed pulps were randomly divided into 3 groups: group 1 (control; ProRoot MTA), group 2 (OST 100 μM + ProRoot MTA), group 3 (OST 10 mM + ProRoot MTA). Exposed pulps were capped with each material and cavities were restored with resin modified glass ionomer. The animals were sacrificed after 4 weeks. All harvested teeth were scanned with micro-computed tomography (CT). The samples were prepared and hard tissue formation was evaluated histologically. For immunohistochemical analysis, the specimens were sectioned and incubated with primary antibodies against dentin sialoprotein (DSP). Results In the micro-CT analysis, it is revealed that OST with ProRoot MTA groups showed more mineralized bridge than the control (p < 0.05). In the H&E staining, it is showed that more quantity of the mineralized dentin bridge was formed in the OST with ProRoot MTA group compared to the control (p < 0.05). In all groups, DSP was expressed in newly formed reparative dentin area. Conclusions OST can be a supplementary pulp capping material when used with MTA to make synergistic effect in hard tissue formation.

Introduction Few studies have reported direct pulp capping in inflamed pulp conditions. The purpose of this study was to investigate the in vitro and in vivo responses of dental pulp during direct pulp capping using various pulp capping materials in inflamed conditions. Methods Human dental pulp cells were treated with lipopolysaccharide (LPS) and cultured with Dycal (Dentsply Caulk, Milford, DE), ProRoot MTA (Dentsply Maillefer, Ballaigues, Switzerland), and Endocem MTA (Maruchi, Wonju, South Korea). The expressions of interleukin (IL)-1β, IL-6, dentin matrix protein 1, and dentin sialophosphoprotein were analyzed through real-time polymerase chain reaction. The maxillary molars of Sprague-Dawley rats were exposed for 2 days. The exposed pulps were capped with Dycal, ProRoot MTA, and Endocem MTA and sealed with resin-modified glass ionomer followed by histologic and immunohistochemical analyses. Results The expression of IL-1β and IL-6 was increased with LPS and decreased by Dycal, ProRoot MTA, and Endocem MTA. Dentin matrix protein 1 and dentin sialophosphoprotein levels were decreased with LPS and increased after treatment with pulp capping materials.In the in vivo study, inflammation associated with Dycal was higher than that associated with ProRoot MTA and Endocem MTA at week 1, without any significant difference between the 2. At 4 weeks, inflammation was decreased, and mineralization was increased compared with week 1 in all 3 of the materials. At week 1, IL-6 immunoreactivity was strongly expressed. Dycal exhibited stronger immunoreactivity than ProRoot MTA and Endocem MTA. However, the immunoreactivity was decreased in all groups at week 4. Conclusions Successful direct pulp capping requires more effective pulp capping materials for the treatment of inflamed pulps.

Clinical Relevance Self-cure after tack cure could result in a lower polymerization shrinkage in some resin-based luting cements, which is closely related to lower degree of cure. SUMMARY Objectives: To evaluate the effect of tack cure on polymerization shrinkage (PS) of resin-based luting cements. Methods and Materials: One composite resin cement, Duo-Link (Duolink); two self-adhesive resin cements, RelyX U200 (U200) and G-CEM LinkAce (GCem); and one resin-modified glass ionomer cement, RelyX Luting Plus (Luting+), were used for measuring PS in light-cure (LC group), self-cure (SC group), and two tack-cure modes that were light cured (TC-LC group) or self-cured (TC-SC group) after tack cure. PS was measured by a modified bonded disc method for 1600 seconds and analyzed with two-way analysis of variance and Tukey honestly significant difference test. To investigate the effect of tack cure on light cure or self-cure, data were analyzed with an independent-samples t-test with tack cure as a variable. The significance level was 5%. Results: Regarding cure mode, Duolink showed a significantly lower PS in the TC-SC group compared with the other groups. Luting+ showed a significantly lower PS in the TC-SC group than in the SC group. U200 showed a significantly lower PS in the self-cure groups compared with that in the light-cure groups. The PS of GCem was not affected by cure mode. Regarding cements, Luting+ showed the highest PS, followed by GCem, Duolink, and U200 (p Conclusion: For the tested cements, tack cure decreased the PS of Duolink and Luting+ when they were self-cured after tack cure. When the cements were light cured after tack cure, PS was not affected by tack cure in any cement.

Mucopolysaccharidosis (MPS) is an inherited metabolic disorder caused by a deficiency in enzymes that participate in the degradation of glycosaminoglycans (GAGs) such as heparin sulfate and dermatan sulfate. Left untreated, patients show progressive mental and physical deterioration due to deposition of GAGs in organs. Death often occurs due to cardiac or respiratory failure before patients reach their early twenties. MPS has several oral and dental manifestations. An enlarged head, short neck, and open mouth associated with a large tongue are major characteristics of MPS patients. Dental complications can be severe, including unerupted dentition, dentigerous cyst-like follicles, malocclusions, condylar defects, and gingival hyperplasia. A 21-year-old female patient with MPS was described in this article, with special emphasis on oral manifestations and dental treatment.

PURPOSE This study aimed to fabricate provisional crowns at varying build directions using the digital light processing (DLP)-based 3D printing and evaluate the marginal and internal fit of the provisional crowns using the silicone replica technique (SRT). MATERIALS AND METHODS The prepared resin tooth was scanned and a single crown was designed using computer-aided design (CAD) software. Provisional crowns were printed using a DLP-based 3D printer at 6 directions (120°, 135°, 150°, 180°, 210°, 225°) with 10 crowns in each direction. In total, sixty crowns were printed. To measure the marginal and internal fit, a silicone replica was fabricated and the thickness of the silicone impression material was measured using a digital microscope. Sixteen reference points were set and divided into the following 4 groups: marginal gap (MG), cervical gap (CG), axial gap (AG), and occlusal gap (OG). The measurements were statistically analyzed using one-way ANOVA and Dunnett T3. RESULTS MG, CG, and OG were significantly different by build angle groups (P

Objective The purpose of this study was to measure the temperature of the plugger tip of 3 cordless heat carriers set at 200°C. Materials and Methods Pluggers of the same taper (0.06, 0.08, 0.10) and similar tip sizes (sizes of 50 and 55) from 3 cordless heat carriers, namely SuperEndo-α2 (B & L Biotech), Friendo (DXM), and Dia-Pen (Diadent), were used and an electric heat carrier, System B (SybronEndo), was used as the control. The plugger tips were covered with customized copper sleeves, heated for 10 seconds, and the temperature was recorded with a computerized measurement system attached to a K-type thermometer at room temperature (n = 10). The data were analyzed with 2-way analysis of variance at a 5% level of significance. Results The peak temperature of the plugger tips was significantly affected by the plugger taper and by the heat carrier brand (p < 0.05). The peak temperature of the plugger tips was between 177°C and 325°C. The temperature peaked at 207°C–231°C for the 0.06 taper pluggers, 195°C–313°C for the 0.08 taper pluggers, and 177°C–325°C for the 0.10 taper pluggers. Only 5 of the 12 plugger tips showed a temperature of 200°C ± 10°C. The time required to reach the highest temperature or 200°C ± 10°C was at least 4 seconds. Conclusion When using cordless heat carriers, clinicians should pay attention to the temperature setting and to the activation time needed to reach the intended temperature of the pluggers.

Purpose: The purpose of this study was to measure the color of low viscosity bulk-fill resin with a capping layer and to compare it with the color of microhybrid composite resin. Materials and Methods: A low viscosity bulk-fill resin (SDR) and microhybrid composite resin of shade A2 (A2) or A3 (A3) were fabricated to 4 mm thickness and light cured for 20 seconds. CIE L*a*b* values of the resin specimens were measured with a colorimeter. Then shade A2 and A3 microhybrid composite resin was capped over low viscosity bulk-fill resins in 2 mm thickness (SA2, SA3). The resin specimens were light cured for 20 seconds and the color was measured and analyzed (n = 10). Color differences (ΔE) between SA2 and A2, SA3 and A3 were also calculated. Results: L* value was highest in SDR followed by SA2 and SA3. L* value of A2 and A3 was the lowest. a* value was lowest in SDR followed by SA2 and SA3, and A2 and A3 was the highest. b* value was lowest in SDR followed by A2 and SA2, and A3 and SA3 was the highest. ΔE between A2 and SA2 (ΔE = 3.4), and that between A3 and SA3 (ΔE = 3.1) was lower than the perceptible color difference threshold of ΔE = 3.7. Conclusion: ΔE between low viscosity bulk-fill resin with a capping layer and microhybrid resin was lower than the perceptible color difference threshold. (J Dent Rehabil Appl Sci 2015;31(4):294-300)

A recent treatment option for non-vital immature teeth in young patients is revascularization with triple antibiotic paste (TAP). However, tooth discoloration was reported with the use of conventional minocycline-containing TAP. In this case report, amoxicillin-containing TAP was used for revascularization of non-vital immature teeth to prevent tooth discoloration. At the 1 yr follow up, the teeth were asymptomatic on clinical examination and showed slight discoloration of the crown due to mineral trioxide aggregate (MTA) filling rather than amoxicillin-containing TAP. Radiographic examination revealed complete resolution of the periapical radiolucency, and closed apex with obvious periodontal ligament space. However, the root growth was limited, and the treatment outcome was more like apexification rather than revascularization. These results may be due to unstable blood clot formation which could not resist the condensation force of MTA filling, whether or not a collagen matrix was in place. These cases showed that although revascularization was not successful, apexification could be expected, resulting in the resolution of the periapical radiolucency and the closure of the apex. Therefore, it is worthwhile attempting revascularization of non-vital immature teeth in young patients.

Traditionally, apexification has been used to treat immature permanent teeth that have lost pulp vitality. This technique promotes the formation of an apical barrier to close the open apex so that the filling materials can be confined to the root canal. Because tissue regeneration cannot be achieved with apexification, a new technique called regenerative endodontic treatment was presented recently to treat immature permanent teeth. Regenerative endodontic treatment is a treatment procedure designed to replace damaged pulp tissue with viable tissue which restores the normal function of the pulp-dentin structure. After regenerative endodontic treatment, continued root development and hard tissue deposition on the dentinal wall can occur under ideal circumstances. However, it is difficult to predict the result of regenerative endodontic treatment. Therefore, the purpose of this study was to summarize multiple factors effects on the result of regenerative endodontic treatment in order to achieve more predictable results. In this study, we investigated the features of regenerative endodontic treatment in comparison with those of other pulp treatment procedures and analyzed the factors that have an effect on regenerative endodontic treatment.

OBJECTIVES: The aim of this study was to investigate the expression of 7 different sirtuin genes (SIRT1-SIRT7) in human dental pulp cells (HDPCs), and to determine the role of SIRTs in the odontoblastic differentiation potential of HDPCs. MATERIALS AND METHODS: HDPCs were isolated from freshly extracted third molar teeth of healthy patients and cultulred in odontoblastic differentiation inducing media. Osteocalcin (OCN) and dentin sialophosphoprotein (DSPP) expression was analyzed to evaluate the odontoblastic differentiation of HDPCs by reverse transcription-polymerase chain reaction (RT-PCR), while alizarin red staining was used for the mineralization assay. To investigate the expression of SIRTs during odontoblastic differentiation of HDPCs, real time PCR was also performed with RT-PCR. RESULTS: During the culture of HDPCs in the differentiation inducing media, OCN, and DSPP mRNA expressions were increased. Mineralized nodule formation was also increased in the 14 days culture. All seven SIRT genes were expressed during the odontogenic induction period. SIRT4 expression was increased in a time-dependent manner. CONCLUSIONS: Our study identified the expression of seven different SIRT genes in HDPCs, and revealed that SIRT4 could exert an influence on the odontoblast differentiation process. Further studies are needed to determine the effects of other SIRTs on the odontogenic potential of HDPCs.

Aberrant anatomy of mandibular premolars is very rare in Korean, but aberration can contribute the endodontic failure as it makes difficult to remove the irritants during cleaning and shaping procedure. This case report describes the successful root canal treatment of a rare mandibular first premolar with C-shaped root canal as using a cone-beam computed tomography to understand the internal shape of root canal system and a dental operating microscope to improve the magnification and illumination.

Introduction Despite good physical and biological properties, mineral trioxide aggregate (MTA) has a long setting time. A hydration accelerator could decrease the setting time of MTA. This study assessed the biocompatibility of MTA mixed with hydration accelerators (calcium chloride and low-dose citric acid) and investigated the effect of these materials on osteoblast differentiation. Methods Cell viability was evaluated by the EZ-Cytox assay kit (Daeil Lab Service, Seoul, Korea). The gene expressions of osteocalcin and bone sialoprotein were detected by reverse-transcription polymerase chain reaction and real-time polymerase chain reaction. The mineralization behavior was evaluated with alizarin red staining. Results There was no statistically significant difference in cell viability between experimental groups. The messenger RNA level of osteogenic genes significantly increased in MTA mixed with hydration accelerators compared with the control and MTA mixed with water. MTA mixed with the hydration accelerators resulted in similar mineralization compared with MTA mixed with water. Conclusions Hydration accelerators increase the osteogenic effect and show a similar effect on the mineralization of MTA, which may have clinical applications.

SUMMARY The purpose of this study was to investigate whether dentin-layer thickness of resin overlays could affect the early hardness and shear bond strength of dual-cure resin cement (DCRC, RelyX ARC) after light curing with light curing units (LCUs) of various power densities: Optilux 360 (360), Elipar Freelight 2 (FL2), and Elipar S10 (S10). Resin overlays were fabricated using an indirect composite resin (Sinfony) with a dentin layer, an enamel layer, and a translucent layer of 0.5 mm thickness each (0.5-0.5-0.5) or of 0.2 mm, 0.5 mm, and 0.8 mm thickness (0.2-0.5-0.8), respectively. The DCRC was light cured for 40 seconds through the overlays, and surface hardness and shear bond strength to bovine dentin were tested 10 minutes after the start of light curing. Surface hardness was higher when the DCRC was light cured through the 0.2-0.5-0.8 combination than when the DCRC was light cured through the 0.5-0.5-0.5 combination with all LCUs. The ratio of upper surface hardness of DCRC light cured through resin overlays relative to the upper surface hardness of DCRC light cured directly was more than 90% only when the DCRC was light cured with S10 through the 0.2-0.5-0.8 combination. The shear bond strength value was higher when the DCRC was light cured with S10 through the 0.2-0.5-0.8 combination than when light cured with S10 through the 0.5-0.5-0.5 combination. This study indicates that reducing the dentin-layer thickness while increasing the translucent-layer thickness of resin inlays can increase the photopolymerization of DCRC, thereby increasing the early bond strength of resin inlays to dentin.

PURPOSE The aim of this study was to determine whether the push-out bond strengths between the radicular dentin and fiber reinforced-composite (FRC) posts with various resin cements decreased or not, according to the coronal, middle or apical level of the root. MATERIALS AND METHODS FRC posts were cemented with one of five resin cement groups (RelyX Unicem: Uni, Contax with activator & LuxaCore-Dual: LuA, Contax & LuxaCore-Dual: Lu, Panavia F 2.0: PA, Super-Bond C&B: SB) into extracted human mandibular premolars. The roots were sliced into discs at the coronal, middle and apical levels. Push-out bond strength tests were performed with a universal testing machine at a crosshead speed of 0.5 mm/min, and the failure aspect was analyzed. RESULTS There were no significant differences (P>.05) in the bond strengths of the different resin cements at the coronal level, but there were significant differences in the bond strengths at the middle and apical levels (P.05); all other groups had a significant decrease in bond strength at the middle or apical level (P

The aim of this study was to evaluate the biocompatibility of mineral trioxide aggregate mixed with selective hydration accelerators such as calcium chloride (CaCl2), citric acid (CA), and calcium lactate gluconate solution (CLG).Inductively coupled plasma-atomic emission spectrometry analysis was used to measure calcium ions in the extracts of test materials. The 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide assay was performed using MG-63 cells to examine the cytotoxicity of the test materials. The surface of each sample and the growth pattern of the attached cells were observed using scanning electron microscopy (SEM).MTA mixed with 10 wt% CaCl2 and MTA mixed with 43.4 wt% CLG released a higher amount of calcium ions than the other groups. The 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide assay revealed that the cell viability of MTA mixed with 0.1 wt% CA was significantly higher than pure MTA on 7-day extract (P.05). MTA mixed with 43.4 wt% CLG showed significantly higher cell viability than the other groups on 1-day extract (P.05). MTA mixed with 10 wt% CaCl2 in all groups showed the lowest cell viability at all time points (P.05). Under SEM, elongated and confluent cells were observed in all samples except in samples of MTA mixed with 10 wt% CaCl2.MTA mixed with 0.1 wt% CA showed good biocompatibility. MTA mixed with 43.4 wt% CLG showed favorable biocompatibility on 1 day. MTA mixed with 10 wt% CaCl2 in all groups showed the lowest cell viability at every time point and poor cell attachment under SEM.

The autogenous tooth transplantation is an alternative treatment replacing a missing tooth when a suitable donor tooth is available. It is also a successful treatment option to save significant amount of time and cost comparing implants or conventional prosthetics. These cases, which required single tooth extraction due to deep caries and severe periodontal disease, could have good results by transplanting non-functional but sound donor tooth to the extraction site.

Introduction Various materials have been advocated for use as root-end filling materials. The purpose of the present in vitro study was to compare the cytotoxicity of 4 root-end filling materials: glass ionomer cement (GIC; Fuji II, GC Corp, Tokyo, Japan), reinforced zinc oxide–eugenol cement (IRM; Dentsply Tulsa Dental, Tulsa, OK), and 2 types of mineral trioxide aggregate. Methods This study used MG-63 cells derived from a human osteosarcoma. To quantitatively evaluate the cytotoxicity of test materials, the 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay was used. The cells were exposed to the extracts and incubated. Cell viability was recorded by measuring the optical density of each test well in reference to controls. Each specimen was examined by scanning electron microscopy for the observation of cell morphology. Results The XTT assay showed that the cell viability of ProRoot MTA (Dentsply Tulsa Dental) was higher than that of GIC and Ortho MTA (BioMTA, Seoul, Republic of Korea) at all time points. IRM showed significantly lower cell viability than the other groups. The scanning electron microscopic analysis revealed that elongated, dense, and almost confluent cells were observed in the cultures of GIC, Ortho MTA, and ProRoot MTA specimens. In contrast, cells on the surface of IRM were rounded in shape, and the numbers and the density of the cells were smaller than that in the other groups. Conclusions ProRoot MTA and GIC showed good biocompatibility in this study. However, Ortho MTA showed lower biocompatibility compared with ProRoot MTA and GIC.

Objectives The purpose of this study was to enhance curing light penetration through resin inlays by modifying the thicknesses of the dentin, enamel, and translucent layers. Materials and Methods To investigate the layer dominantly affecting the power density of light curing units, resin wafers of each layer with 0.5 mm thickness were prepared and power density through resin wafers was measured with a dental radiometer (Cure Rite, Kerr). The dentin layer, which had the dominant effect on power density reduction, was decreased in thickness from 0.5 to 0.1 mm while thickness of the enamel layer was kept unchanged at 0.5 mm and thickness of the translucent layer was increased from 0.5 to 0.9 mm and vice versa, in order to maintain the total thickness of 1.5 mm of the resin inlay. Power density of various light curing units through resin inlays was measured. Results Power density measured through 0.5 mm resin wafers decreased more significantly with the dentin layer than with the enamel and translucent layers (p < 0.05). Power density through 1.5 mm resin inlays increased when the dentin layer thickness was reduced and the enamel or translucent layer thickness was increased. The highest power density was recorded with dentin layer thickness of 0.1 mm and increased translucent layer thickness in all light curing units. Conclusions To enhance the power density through resin inlays, reducing the dentin layer thickness and increasing the translucent layer thickness would be recommendable when fabricating resin inlays.

Introduction This study compared the fracture resistances and the failure patterns of 100 simulated mandibular premolars of a different number of coronal walls (zero to four walls) with or without fiber-reinforced composite (FRC) posts. In addition, the photoelastic stress distribution was analyzed. Methods The fracture resistance was measured at a 45° angle with a crosshead speed of 1 mm/min, and the failure patterns were observed. The photoelastic stress distribution of specimens with or without FRC posts was also evaluated. The fracture resistance was analyzed by analysis of variance and a Duncan's multiple range test (p Results In the no post groups, the fracture resistances decreased significantly in groups with two or fewer walls. The FRC post increased fracture resistances significantly, except for the zero-wall group, and optimized the failure patterns. A high stress concentration was observed along the canal space in the no post groups; stress seemed to be distributed in post groups in photoelasticity. Conclusion Within the limitation of the experimental methods of this study, the FRC post was advantageous in lower premolars, especially with two or more walls in terms of the fracture resistance and stress distribution.