Dental Materials Journal
Online ISSN : 1881-1361
Print ISSN : 0287-4547
ISSN-L : 0287-4547
Volume 37, Issue 5
Displaying 1-20 of 20 articles from this issue
Original Paper
  • Giacomo DERCHI, Michele VANO, Luca CESERACCIU, Alberto DIASPRO, Marco ...
    2018 Volume 37 Issue 5 Pages 709-716
    Published: September 27, 2018
    Released on J-STAGE: September 30, 2018
    Advance online publication: July 26, 2018
    JOURNAL FREE ACCESS

    We investigated three bulk fill composites (Mat1, Mat2, Mat3) cured by two polywave (Poly1, Poly2) and one monowave (Mono) lamps. We used infrared spectroscopy, nanoindentation and atomic force microscopy to assess degree of conversion (DC), stiffness, and roughness after polishing, respectively. Mat2 exhibited the highest DC with Poly1 and second highest with Mono, however was the less stiff. Both Mat1 and Mat3 showed highest DC with Poly2, while Poly1 scored better than Mono. Mat3 scored better than Mat1 and was the third highest when cured with Poly2. For each composite cured by different lamps the stiffness ranked same as the DC. However, roughness did not correlate with hardness. Absolute stiffness value depends on composite formulation. Polywave lamps work better than monowave but not in all cases, as Mat2 showed higher DC with Mono than with Poly2. However, all lamps guarantee a DC≥50% but Mono for Mat1.

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  • Guangyun LAI, Liya ZHAO, Jun WANG, Karl-Heinz KUNZELMANN
    2018 Volume 37 Issue 5 Pages 717-724
    Published: September 27, 2018
    Released on J-STAGE: September 30, 2018
    Advance online publication: July 12, 2018
    JOURNAL FREE ACCESS

    This study evaluated surface gloss, roughness and color change of six current flowable composites after simulated toothbrushing, including four traditional flowable composites (i.e. GrandioSO Flow, Arabesk Flow, Kerr Revolution Formula 2 and Gradia Direct LoFlo), one self-adhering flowable composite (Kerr Vertise Flow) and one universal injectable composite (G-ænial Universal Flo). Forty-eight dimensionally standardized specimens (n=8/group) were made from six composites. Before and after 1 h toothbrushing simulation, surface gloss was measured with a glossmeter, and surface roughness was evaluated with a profilometer, and color was measured with a spectrophotometer. In this study, G-ænial Universal Flo, termed as universal injectable composite by the manufacturer, presented excellent surface properties after toothbrush abrasion; Gradia Direct LoFlo showed excellent color stablity after toothbrush abrasion; color alteration of composites caused by toothbrush abrasion was acceptable on the premise that 3.3∆E units were considered as acceptable threshold values.

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  • Nathalia ALBRECHT, Tatiana Kelly DA SILVA FIDALGO, Maria José Santos D ...
    2018 Volume 37 Issue 5 Pages 725-733
    Published: September 27, 2018
    Released on J-STAGE: September 30, 2018
    Advance online publication: June 20, 2018
    JOURNAL FREE ACCESS

    Two soft denture lining materials (SC-Soft Confort and TS-Trusoft) were investigated with and without the addition of 1.0% of chlorhexidine diacetate (1.0% CHX). To assess peel bond strength, specimens (75×10×6 mm) were submitted to a peel test at 10 mm/min immediately and after 24 h. To evaluate Candida albicans growth inhibition, disc of specimens (10×3 mm) were immersed in a solution with 3×106 CFU/mL of C. albicans, and spectral measurements were made following immersion in MTT solution for 2, 4, and 6 days. The agar diffusion test was performed by investigating the diameters of inhibition zones around the disc of specimens (10×3 mm)after 48 h. Data were submitted to statistical analysis (α=0.05) and the failure modes were visually classified. The incorporation of 1.0% CHX significantly decreased the peel bond strength for TS (p=0.001) and SC (p=0.005) for immediate test and for TS after 24 h (p=0.010), but not for SC. C. albicans growth was decreased for both materials over time (p<0.05). SC presented inhibition zones approximately 2.0 times larger than TS. The incorporation of 1.0% CHX inhibited fungal growth without impairment to the peel bond strength for SC after 24 h.

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  • Akifumi TAKAHASHI, Tomohiro TAKAGAKI, Takahiro WADA, Motohiro UO, Toru ...
    2018 Volume 37 Issue 5 Pages 734-739
    Published: September 27, 2018
    Released on J-STAGE: September 30, 2018
    Advance online publication: July 26, 2018
    JOURNAL FREE ACCESS

    The effects of contamination and cleaning methods on bonding of self-adhesive resin cement to zirconia ceramics were examined. Airborne particle-abraded zirconia (Zpex Smile) specimens were divided into the following four groups: control (con), contaminated with saliva and cleaned with tap water (HS), cleaned with Ivoclean (IC), and cleaned with Multi Etchant (ME). The pretreated specimens were bonded using three self-adhesive resin cements, and tensile bond strengths were measured using a universal testing machine at a crosshead speed of 2 mm/min. Con and IC groups showed significantly higher bond strength than those of HS and ME groups. Separately, the surface chemical composition of the groups was determined using X-ray photoelectron spectroscopy (XPS). XPS revealed that the N/Zr ratio increased in the HS group but decreased in the IC and ME groups. Cleaning agents can improve the adverse effect of saliva contamination on zirconia, but this effect varies depending on the product.

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  • Ryo NISHIKIORI, Masahiko SAWAJIRI, Tetsuji OKUDA, Atsunori OTOSHI, Kot ...
    2018 Volume 37 Issue 5 Pages 740-745
    Published: September 27, 2018
    Released on J-STAGE: September 30, 2018
    Advance online publication: May 31, 2018
    JOURNAL FREE ACCESS

    Infection control of dental stone cast is an important issue. Ozone is effective for disinfection against microorganisms and inactivation of viruses. However, there is little information regarding the use of ozone. We prepared 4 types of gypsum specimens and 3 types of disinfectants (4–5 ppm Ozonated water [OZW], 2% glutaraldehyde [GL], and 1% sodium hypochlorite [SH]). Gypsum specimens were immersed in each disinfectant for 5 and 10 min, and surface roughness was then examined using laser scanning microscopy. Surface microstructure was investigated using scanning electron microscopy. Immersion of gypsum specimens in SH, GL, and OZW increased the surface roughness to a maximum of 1.04, 0.37, and 0.30 μm, respectively, based on the difference between the average values of surface roughness before and after the disinfection procedure. The effects of OZW and GL were comparable. OZW is useful as a candidate for relatively safe disinfection of material for dental stone casts.

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  • Mohammed M GAD, Ahmed RAHOMA, Ahmad M Al-THOBITY
    2018 Volume 37 Issue 5 Pages 746-753
    Published: September 27, 2018
    Released on J-STAGE: September 30, 2018
    Advance online publication: June 20, 2018
    JOURNAL FREE ACCESS

    The current study evaluated the effects of autoclave polymerization both with and without glass fiber (GF) reinforcement on the surface roughness and hardness of acrylic denture base material. Ninety disc specimens (30×2.5 mm) were prepared from Vertex resin and divided according to polymerization techniques into a water bath, short and long autoclave polymerization groups. Tested groups were divided into three subgroups according to the GF concentration (0, 2.5, and 5 wt%). Profilometer and Vickers hardness tests were performed to measure surface roughness and hardness. ANOVA and Tukey-Kramer multiple comparison tests analyzed the results, and p≤0.05 was considered statistically significant. Autoclave polymerization significantly decreased the surface roughness and increased the hardness of acrylic resin without GF reinforcement (p<0.05). However, 5 wt% GF addition significantly increased surface roughness and decreased hardness of the autoclave polymerized denture base resin (p<0.05). Surface properties of Polymethyl methacrylate (PMMA) denture base material improved with autoclave polymerization and negatively affected with GFs addition.

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  • Minh Nguyet LUONG, Yasushi SHIMADA, Alireza SADR, Masahiro YOSHIYAMA, ...
    2018 Volume 37 Issue 5 Pages 754-760
    Published: September 27, 2018
    Released on J-STAGE: September 30, 2018
    Advance online publication: May 31, 2018
    JOURNAL FREE ACCESS

    This study determined the influence of thermocycling (TC) and flowable composite on microtensile bond strength (MTBS), crack formation and mechanical properties of the bonding interface using swept-source optical coherence tomography (SS-OCT) and nanoindentation. MTBS test beams prepared from human dentin bonded with self-etch adhesive and hybrid composite with or without flowable lining were aged for either 0 or 10,000 thermocycles, resulting in 4 groups of specimens according to the placement technique and TC (n=10). 2D images were obtained before and after MTBS test to detect crack at interface using SS-OCT. Hardness across resin-dentin bonding area were measured using nanoindentation. Two-way ANOVA showed that flowable lining significantly increased MTBS (p<0.05). TC significantly increased crack percentage in composite while there was no significant difference in dentin crack. Moreover, TC significantly affected the hardness of dentin and resin composites (p<0.05). SS-OCT is effective in detecting internal fracture in substrate.

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  • Zhongjun LIU, Xinyuan ZHAO, Xiongqun ZENG, Shuaimei XU, Yu LU, Dingmin ...
    2018 Volume 37 Issue 5 Pages 761-767
    Published: September 27, 2018
    Released on J-STAGE: September 30, 2018
    Advance online publication: June 20, 2018
    JOURNAL FREE ACCESS

    Resin adhesive restorations are susceptible to oral fluid contamination and greatly influenced by dentinal tubule fluid because of pulpal pressure, especially when the restorative cavities are near gingival tissues. This study designed a novel model to evaluate the microleakage of self-adhesive flowable composite and traditional resin adhesives under simulated subgingival cavity preparations and pulpal pressure. We applied three different adhesive systems, include Vertise Flow, Optibond all-in-one, and Optibond S, on premolars with V-shaped cavity. All samples exhibited good marginal sealing at resin-enamel interfaces. At resin-dentin interfaces, microleakage in control group was similar among different adhesive systems. Microleakage in group pulpal pressure was greater than that in control group for all adhesive systems except Vertise Flow. All adhesive systems in pulpal pressure and simulated subgingival group exhibited significantly greater microleakage. In total, Vertise Flow exhibited better marginal sealing under pulpal pressure than other traditional adhesives.

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  • Noboru KAJIMOTO, Emi UYAMA, Kazumitsu SEKINE, Kenichi HAMADA
    2018 Volume 37 Issue 5 Pages 768-774
    Published: September 27, 2018
    Released on J-STAGE: September 30, 2018
    Advance online publication: May 31, 2018
    JOURNAL FREE ACCESS

    With improvement of bonding strength of recent dental cement, it is difficult nowadays to remove restorations without excessive force or vibration to tooth, occasionally resulting in damage of dentin, enamel, and dental root. Therefore, “smart” dental cement indicating strong bonding and easy debonding-on-demand simultaneously is required. In this research, resin-modified glass-ionomer-cement containing an ionic-liquid, tris(2-hydroxyethyl)methylammonium methylsulfate was produced, and the shear bonding strength before and after direct current application were evaluated. The prototype cement containing 15 to 20 mass% ionic-liquid indicated simultaneously no significant reduction of shear bonding strength from that of the original cement not containing ionic-liquid, and significant reduction of bonding strength to approximately 20% of that of the original cement after direct current application of more than 2 mmC/mm2. The prototype cement in this research demonstrated that the concept of smart dental cement electrically debonding-on-demand is feasible.

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  • Junji ATOMURA, Go INOUE, Toru NIKAIDO, Keisuke YAMANAKA, Motohiro UO, ...
    2018 Volume 37 Issue 5 Pages 775-782
    Published: September 27, 2018
    Released on J-STAGE: September 30, 2018
    Advance online publication: June 20, 2018
    JOURNAL FREE ACCESS

    FCP-COMPLEX is a newly developed solution containing fluoride, calcium, and phosphoric acid that has the potential to reinforce caries-affected dentin. This study evaluated the effect of FCP-COMPLEX on micro-tensile bond strength (µTBS) and acid-challenge at the dentin-adhesive interface. FCP-COMPLEX, 2% NaF, and distilled water were applied to artificial caries-affected dentin (ACAD) and the effect on acid-induced damage after resin composite restoration was observed. Scanning electron microscopy and X-ray absorption fine structure (XAFS) were used to evaluate tooth morphology. The µTBS test revealed no effect of FCP-COMPLEX either immediately or after 3 months’ storage. The area of acid damage in caries-affected dentin was reduced by FCP-COMPLEX. XAFS analysis revealed that absorbed fluorine on the surface would form CaF2. In conclusion, FCP-COMPLEX significantly reduced the damage of acidic attack at the ACAD-adhesive interface, while the µTBS value was maintained after storage.

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  • Kwang-Hyun SONG, Yong-Woon IM, Jung-Hwan LEE, Jonghyuk LEE, Hae-Hyoung ...
    2018 Volume 37 Issue 5 Pages 783-788
    Published: September 27, 2018
    Released on J-STAGE: September 30, 2018
    Advance online publication: March 07, 2018
    JOURNAL FREE ACCESS

    This study aimed to evaluate the mold-enclosed shear bond strength (ME-SBS) of zirconia to veneering porcelain with different surface treatments. Colored or uncolored zirconia coupons were either highly polished or airborne-particle abraded. The specimens were divided into groups with/without application of liner. Veneering porcelain was fired into an alumina ring mold on the zirconia coupons. The assembled specimens were subjected to the ME-SBS test. The mean ME-SBS for groups ranged from 7–10 MPa with no significant difference (p>0.05). A three-way ANOVA showed that coloring and surface roughening of the zirconia specimen had no significant influence on the ME-SBS value, but liner application exhibited a significant effect with a minor decrease in the MESBS (p=0.049). Surface treatments (coloring, airborne-particle abrasion, and liner application) were found to not cause a significant increase to the zirconia-porcelain bond strength. The application of zirconia liner had a slight negative influence on the ME-SBS results.

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  • Xiuzhi FEI, Zeyang WANG, Wei ZHONG, Yinglou LI, Yanyu MIAO, Longbo ZHA ...
    2018 Volume 37 Issue 5 Pages 789-797
    Published: September 27, 2018
    Released on J-STAGE: September 30, 2018
    Advance online publication: June 29, 2018
    JOURNAL FREE ACCESS

    This study was to compare the influence of glass fiber post placement and crown restoration on endodontically treated maxillary first premolars with severe NCCLs using three-dimensional finite element analysis and fracture resistance testing. G1, intact teeth. G2, teeth with artificial defect. G3, composite resin (CR). G4, CR and fiber post in buccal canal (FPB). G5, CR and fiber post in palatal canal (FPP). G6, CR and fiber posts in buccal and palatal canals (FPBP). G7, CR and crown (C). G8, CR, FPB, C. G9, CR, FPP, C. G10, CR, FPBP, C. Teeth in G2, G3, and G5 showed a similar stress concentration at the tip of the defect. The fracture resistance of G2 did not differ significantly from G3 and G5 (p>0.05) but differed significantly from that in other groups (p<0.05). The fractures in G4 were more favorable, and the difference of those in G1 from those in G7, G8, G9, and G10 was statistically significant (p<0.05). Restoration of root-filled maxillary premolars with severe NCCLs using fiber post in the buccal canal may be more efficacious than other restoration methods.

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  • Xiao-Ming ZHU, Jian-Feng ZHOU, Heng GUO, Xiao-Fei ZHANG, Xiao-Qiang LI ...
    2018 Volume 37 Issue 5 Pages 798-804
    Published: September 27, 2018
    Released on J-STAGE: September 30, 2018
    Advance online publication: June 29, 2018
    JOURNAL FREE ACCESS

    The radio-frequency atmospheric-pressure glow discharge (RF-APGD) plasma is a novel cold atmospheric plasma (CAP) source, which has low energy characteristic. This study investigated the effect of RF-APGD plasma on the mechanical properties of dentin collagen and resin-dentin bonding. The scanning electron microscopy analysis was performed before and after a novel RF-APGD plasma and a conventional CAP treatment and a tensile test was carried out for the stiffness of dentin collagen. The microtensile resin-dentin bond strength was tested either immediately or after a 50,000-cycle thermocycling process. Dentin collagen maintained an intact structure after a 45-s RF-APGD plasma treatment, whereas even a 10-s treatment with the conventional CAP collapsed the collagen scaffold. When compared with control groups, the RF-APGD plasma treatment showed: (i) an improved stiffness of dentin collagen; (ii) a significant improvement in the bonding strength before/after artificial aging. Thus, RF-APGD plasma treatment has excellent prospects as a resin-dentin bonding protocol.

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  • Yuki NARUSE, Tomohiro TAKAGAKI, Naoko MATSUI, Takaaki SATO, Alghamdi A ...
    2018 Volume 37 Issue 5 Pages 805-811
    Published: September 27, 2018
    Released on J-STAGE: September 30, 2018
    Advance online publication: July 26, 2018
    JOURNAL FREE ACCESS

    The aim of this study was to evaluate how alumina-blasting pressure affects the bond strength of CAD/CAM resin blocks (CRBs) to bovine dentin using two different types of resin cements. CRB slices were divided into three groups by alumina-blasting pressure, namely, untreated and 0.1 MPa and 0.2 MPa, and further divided into three subgroups by combination of CRBs surface treatment and types of cement: Scotchbond Universal and RelyX ultimate (RXB), Scotchbond Universal and RelyX unicem2 (U2B), ceramic primer and RelyX unicem2 (U2C). The CRB slices were then cemented to bovine dentin, microtensile bond strength test was performed and evaluated. Regardless of the alumina-blasting pressure, RXB group have the highest µTBS and bond strength tends to increase with increasing alumina-blasting pressure. Alumina-blasting to CRB surface by at an appropriate pressure and use of conventional resin cement were required to obtain strong adhesion with the tooth structure.

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  • Anja LIEBERMANN, Caroline FREITAS RAFAEL, Ana Elisa COLLE KAULING, Dan ...
    2018 Volume 37 Issue 5 Pages 812-817
    Published: September 27, 2018
    Released on J-STAGE: September 30, 2018
    Advance online publication: July 12, 2018
    JOURNAL FREE ACCESS

    The aim of this study was to evaluate the transmittance of visible light (VL) (λ: 400–700 nm) and blue light (BL) (λ: 360–540 nm) through six CAD/CAM zirconia blanks (ZiB) in comparison to a lithium disilicate ceramic (LS2). Disks of the zirconia materials Bruxzir (BX), Cercon (CE), Lava Frame (LF), Lava Plus (LP), Prettau (PT), Zenostar (ZS) and LS2 (EM) were manufactured and the transmittance was measured in a spectrophotometer. ZS, followed by CE, PT, LP, LF, and BX showed the lowest transmittance of VL and BL. The highest transmittance was shown by EM. The transmittance of BL was lower than that of VL in all groups. EM ceramics showed higher transmittance than all zirconia materials and the thickness of zirconia materials influenced the transmittance values. Knowledge about VL and BL transmittance would help clinicians to individually tailor the selection of material to the specific indication and to make the right choice regarding the luting procedure and light curing duration.

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  • Feng LUO, Guang HONG, Tong WANG, Lingling JIA, Jun-Yu CHEN, Lai SUO, X ...
    2018 Volume 37 Issue 5 Pages 818-824
    Published: September 27, 2018
    Released on J-STAGE: September 30, 2018
    Advance online publication: June 29, 2018
    JOURNAL FREE ACCESS

    This study evaluated the wettability of commercial vinyl polysiloxane impression materials by measuring contact angles on horizontal and non-horizontal surfaces using artificial saliva. Three light bodies (Affinis [Affi], Silagum [Sila] and Variotime [Vario-LB]) and one extra light body (Viriotime [Vario-ELB]) were prepared with flat surfaces. Static and dynamic contact angles were measured using the sessile drop method as a function of time. Contact angle hysteresis was the value of advancing contact angle minus receding contact angle. The results indicated that all materials were classified as hydrophilic materials. Vario-ELB and Affi showed better initial wettability than the other two materials. Vario-ELB showed more hydrophilic properties and was more vulnerable to changes in the intraoral environment compared to Affi, Sila and Vario-LB. These results suggest that measuring the time-dependent dynamic contact angle on the inclined surface can provide effective information regarding the wettability of impression materials to evaluate their clinical performance.

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  • Xavier STRUILLOU, Aurélien FRUCHET, Mia RAKIC, Zahi BADRAN, Gildas RET ...
    2018 Volume 37 Issue 5 Pages 825-834
    Published: September 27, 2018
    Released on J-STAGE: September 30, 2018
    Advance online publication: June 20, 2018
    JOURNAL FREE ACCESS

    The aim of the study was to evaluate bone regeneration using a canine model with surgically created periodontal defects filled for 12 weeks using a stratified biomaterial consisting in a biphasic calcium phosphate (BCP) covered with a crosslinking hydrogel acting as polymer membrane of silated hydroxypropyl methylcellulose (Si-HPMC) as the tested new concept. Bilateral, critical-sized, defects were surgically created at the mandibular premolar teeth of six adult beagle dogs. The defects were randomly allocated and: (i) left empty for spontaneous healing or filled with: (ii) BCP and a collagen membrane; (iii) BCP and hydrogel Si-HPMC membrane. At 12 weeks, the experimental conditions resulted in significantly enhanced bone regeneration in the test BCP/Si-HPMC group. Within the limits of this study, we suggest that the hydrogel Si-HPMC may act as an occlusive barrier to protect bone area from soft connective tissue invasion and then effectively contribute to enhance bone regeneration.

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  • Roberta CONDO’, Luca PAZZINI, Loredana CERRONI, Guido PASQUANTONIO, Gi ...
    2018 Volume 37 Issue 5 Pages 835-842
    Published: September 27, 2018
    Released on J-STAGE: September 30, 2018
    Advance online publication: July 12, 2018
    JOURNAL FREE ACCESS

    Aim of this in vitro study was to analyze structural properties of two different polymeric orthodontic aligners, Exceed30 (EX30) and Smart Track (LD30), before and after use. Forty patterns of aligners were randomly selected: 20 LD30 and 20 EX30, worn intra-orally for 14±3 days, 22 h/day. From each aligner, 10 specimens were prepared from buccal surfaces of the incisor region by the cutting of samples 5×5 mm under a stereomicroscope. All samples were subjected to Fourier transform infrared spectroscopy, micro-Raman spectroscopy, X-ray diffraction, tensile and indentation strength test. LD30 appeared more homogeneous, with a crystalline fraction lower than EX30 and exhibited a higher elastic behavior and a lower tendency to warp after use than EX30. LD30 demonstrated better adaptability to the dental arch and greater consistency of application of orthodontic forces than produced with EX30. However, both materials showed structural modifications that resulted in increased sample hardness and hyper-plasticity.

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  • Yu TSUYUKI, Toru SATO, Syuntaro NOMOTO, Mamoru YOTSUYA, Teruyoshi KOSH ...
    2018 Volume 37 Issue 5 Pages 843-850
    Published: September 27, 2018
    Released on J-STAGE: September 30, 2018
    Advance online publication: June 29, 2018
    JOURNAL FREE ACCESS

    The aim of this study was to investigate the effects of occlusal form of abutment, occlusal thickness of monolithic zirconia crowns (MZC), and cement type on the fracture load of MZC. Abutments were prepared with 2 types of occlusal forms: groove-type and flat-type. These were designed so that thickness at the central fissure region of MZC was 0.3, 0.5, or 0.7 mm. Glass ionomer cement and resin cement were used to lute MZC to their corresponding abutment. Fracture load was determined using a universal testing machine. As a result, groove-type abutment had lower fracture load compared to flat-type abutment; however, the decline in strength was smaller when resin cement was used. Additionally, specimens with larger occlusal thickness had greater fracture load regardless of groove or cement-type. The fracture of MZC occurred on the central fissure region of MZC except for 0.7 mm groove-type MZC luted with resin cement.

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  • Guanjun ZHOU, Xiaoli ZHANG, Hui QIE, Chenxi LI, Lin LU, Lihua SHAN
    2018 Volume 37 Issue 5 Pages 851-857
    Published: September 27, 2018
    Released on J-STAGE: September 30, 2018
    Advance online publication: September 14, 2018
    JOURNAL FREE ACCESS

    To investigate the cause of mandibular implant loss, we evaluated the stress distribution in the bone under bite force when the miniimplant was near the root using three-dimensional finite element analysis. Our analysis involved four finite element models with different distances between the implant and adjacent tooth root and three loading conditions. With loading of the tooth only or both the tooth and implant, the peak stress within the bone around the implant neck, displacement, and stress surrounding the bone near the root increased as the distance between the implant and root decreased. However, with separate loading of the implant, the stress did not correlate with the distance between the implant and root. Application of bite force increases stress within bones surrounding mini-implants near the roots of adjacent teeth and may threaten implant stability, but simple orthodontic loading has little effect on the stress distribution at the mini-implant–bone interface.

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