PURPOSE: The purpose of this study was to evaluate the machining accuracy and consistency of implant/abutment/screw combination of internal connection type. MATERIAL AND METHODS: In this study, each two randomly selected internal implant fixtures from ITI, 3i, Avana, Bicon, Friadent, Astra, and Paragon system were used. Each abutment was connected to the implant with 32Ncm torque value using a digital torque controller or tapping. All samples were cross-sectioned with grinder-polisher unit (Omnilap 2000 SBT Inc) after embeded in liquid unsaturated polyester (Epovia, Cray Valley Inc). Then optical microscopic and scanning electron microscopic(SEM) valuations of the implant-abutment interfaces were conducted to assess quality of fit between the mating components. RESULTS: 1) Generally, the geometry of the internal connection system provided for a precision fit of the implant/abutment interface. 2) The most precision fit of the implant/abutment interface was provided in the case of Bicon System which has not screw. 3) The fit of the implant/abutment interface was usually good in the case of ITI, 3I and Avana system and the amount of fit of the implant/abutment interface was similar to each other. 4) The fit of the implant/abutment interface was usually good in the case of Friadent, Astra and Paragon system. The case of Astra system with the inclined contacting surface had the most intimate contact among them. 5) Amount of intimate contact in the abutment screw thread to the mating fixture was larger in assembly with two-piece type which is separated screw from abutment such as Friadent, Astra and Paragon system than in that with one-piece type which is not seperated screw from abutment such as ITI, 3I and Avana system. 6) Amount of contact in the screw and the screw seat of abutment was larger in assembly of Friadent system than in asembly of Astra system or Paragon system. CONCLUSION: Although a little variation in machining accuracy and consistency was noted in the samples, important features of all internal connection systems were the deep, internal implant - abutment connections which provides intimate contact with the implant walls to resist micromovement, resulting in a strong stable interface. From the results of this study, further research of the stress distribution according to the design of internal connection system will be required.
Polyesters ; Torque

The purpose of this study was to evaluate the difference of surface roughness of composite resin according to composite resin type, polishing methods, and use of resin sealant. Two hundred rectangular specimens, sized 8 x 3 x 2 mm, were made of Micro-new (Bisco, Inc., Schaumburg, IL, U.S.A) and Filtek Supreme (3M ESPE Dental Products, St. Paul, MN, U.S.A.), and divided into two groups; Micronew-M group, Filtek Supreme-S group. Specimens for each composite group were subdivided into five groups by finishing and polishing instruments used; M1 & S1 (polyester strip), M2 & S2 (Sof-Lex disc), M3 & S3 (Enhance disc and polishing paste), M4 & S4 (Astropol), and M5 & S5 (finishing bur). Polished groups were added letter B after the application of resin surface sealant (Biscover), eg, M1B and S1B. After specimens were stored with distilled water for 24 hr, average surface roughness (Ra) was taken using a surface roughness tester. Representative specimens of each group were examined by FE-SEM (S-4700: Hitachi High Technologies Co., Tokyo, Japan). The data were analysed using paired t-test, ANOVA and Duncan's tests at the 0.05 probability level. The results of this study were as follows; 1. The lowest Ra was achieved in all groups using polyester strip and the highest Ra was achieved in M5, S5 and M5B groups using finishing bur. On FE-SEM, M1 and S1 groups provided the smoothest surfaces, M5 and S5 groups were presented the roughest surfaces and voids by debonding of filler on the polished specimens. 2. There was no significant difference in Ra between Micronew and Filtek Supreme before the application of resin sealant, but Micronew was smoother than Filek Supreme after the application of resin sealant. 3. There was significant corelation between Ra of type of composite resin and polishing methods before the application of resin sealant (p = 0.000), but no significant interaction between them after the application of resin sealant. On FE-SEM, most of composite resin surfaces were smooth after the application of resin sealant on the polished specimens. 4. Compared with before and after the application of resin sealant in group treated in the same composite and polishing methods, Ra of M4B and M5B was statistically lower than that of M4 and M5, and S5B was lower than that of S5, respectively (p < 0.05). In conclusion, surface roughness by polishing instruments was different according to type of composite resin. Overall, polyester strip produced the smoothest surface, but finishing bur produced the roughest surface. Application of resin sealant provided the smooth surfaces in specimens polished with Enhance, Astropol and finishing bur, but not provided them in specimens polished with Sof-Lex disc.
Polyesters ; Water

STATEMENT OF PROBLEM: Accurate fit between the implant components is important because the misfit of the implant components results in frequent screw loosening, irreversible screw fracture, plaque accumulation, poor soft tissue reaction, and destruction of osseointegration. PURPOSE: This study is to evaluate the machining accuracy and consistency of the implant fixture/abutment/screw interfaces of the internal connection system by using a Stereoscopic Zoom microscope and FE-SEM(field emission scanning electron microscope) MATERIALS AND METHODS: The implant systems selected in this study were internal connection type implants from AVANA(Osstem(R)), Bioplant(Cowell-Medi(R)), Dio(DIO(R)), Neoplant(Neobiotech (R)), Implantium(Dentium(R))systems. Each group was acquired 2 fixtures at random. Two piece type abutment and one piece type abutment for use with each implant system were acquired. Screw were respectively used to hold a two piece type abutment to a implant fixture. The implant fixtures were perpendiculary mounted in acrylic resin block. Each two piece abutment was secured to the implant fixture by screw and one piece abutment also secured to the implant fixture. Abutment/fixture assembly were mounted in liquid unsaturated polyester. All samples were cross-sectioned with grinder-polisher unit. Finally all specimens were analysed the fit between implant fixture/abutment/screw interfaces Results and CONCLUSIONS: 1. Implant fixture/abutment/screw connection interfaces of internal connection systems made in Korea were in good condition. 2. The results of the above study showed that materials and mechanical properties and quality of milling differed depending on their manufacturing companies.
Korea ; Osseointegration ; Polyesters

No abstract available.
Polyesters* ; Urinary Incontinence*

Polylactide and its copolymers are a kind of biomedical material andhave been approved by U.S. Food and Drug Administration. This paper briefly introduces its applications in surgical suture, orthopedics, plastic surgery, ophthalmology and other medical device fields, and also analyzes its development in our country.
Biocompatible Materials ; Polyesters

With the environmental pollution caused by waste plastics becoming increasingly serious, biodegradable polyester has become the focus of public attention. Poly(butylene adipate-co-terephthalate) (PBAT) is a biodegradable polyester formed by the copolymerization of aliphatic and aromatic groups, which has excellent performance of both. The degradation of PBAT under natural conditions requires strict environmental conditions and long degradation cycle. To address these shortcomings, this study explored the application of cutinase in PBAT degradation and the impact of butylene terephthalate (BT) content on the biodegradability of PBAT, so as to improve the degradation rate of PBAT. Five Polyester degrading enzymes from different sources were selected to degrade PBAT to pick out the most efficient enzyme. Subsequently, the degradation rate of PBAT materials with different BT content were determined and compared. The results showed that cutinase ICCG was the best enzyme for PBAT biodegradation, and the higher the BT content, the lower the degradation rate of PBAT. Furthermore, the optimum temperature, buffer type, pH, the ratio of enzyme to substrate (E/S) and substrate concentration in the degradation system were determined to be 75 ℃, Tris HCl, 9.0, 0.4% and 1.0% respectively. These findings may facilitate the application of cutinase in PBAT degradation.
Polyesters/chemistry* ; Adipates

Municipal sewage treatment plants (STPs) are thought to be important point sources of microplastics in freshwater systems and many peer-reviewed articles have been published on this issue since mid-2010s. In this review, we summarize existing literature on the occurrence of microplastics in STPs and experimental methods used for isolation and identification of microplastics. The number concentrations of microplastics in STP influents were 15.1-640 L⁻¹, whereas those in the STP effluents were highly variable and ranged from not detectable to 65 L⁻¹. For most of cases, conventional STPs are removing microplastics very effectively. Fragments and fibers are dominant shapes of microplastics. Thermoplastics (polyethylene and polypropylene) and polyester are the predominant materials recovered. Although further research is needed, size distribution of microplastics in STPs is likely to follow a power law, implying that different studies using different size cutoffs may be compared after establishing a power law relationship.
Fresh Water ; Jurisprudence ; Polyesters ; Sewage*

No abstract available.
Adhesives* ; Cyanoacrylates* ; Herniorrhaphy* ; Polyesters* ; Titanium*

Municipal sewage treatment plants (STPs) are thought to be important point sources of microplastics in freshwater systems and many peer-reviewed articles have been published on this issue since mid-2010s. In this review, we summarize existing literature on the occurrence of microplastics in STPs and experimental methods used for isolation and identification of microplastics. The number concentrations of microplastics in STP influents were 15.1-640 L⁻¹, whereas those in the STP effluents were highly variable and ranged from not detectable to 65 L⁻¹. For most of cases, conventional STPs are removing microplastics very effectively. Fragments and fibers are dominant shapes of microplastics. Thermoplastics (polyethylene and polypropylene) and polyester are the predominant materials recovered. Although further research is needed, size distribution of microplastics in STPs is likely to follow a power law, implying that different studies using different size cutoffs may be compared after establishing a power law relationship.
Fresh Water ; Jurisprudence ; Polyesters ; Sewage

Star-shaped polymer of epoxidized soybean oil (ESO) and lactide is a new material. Its degradation function has an importance to its applications. There are many factors affecting its degradation. This paper is mainly aimed at investigation in which the surface morphology, pH, molecular weight and weight loss rate, branching ESO-lactide star polymers the degree of change were studied. It was found through the experiments that, the changing rates of the branching ESO-lactide star polymers were slower than the degree of PDLLA change compared to the surface morphology, pH, molecular weight and weight loss rate. This has a guiding significance to the further application of ESO-lactide.
Polyesters ; chemistry ; Polymers ; chemistry ; Soybean Oil ; chemistry