Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Titanium”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,639 records · Page 91Linked to original sources
PubMedDate not supplied

Bone density around titanium implants may be influenced by intermittent cigarette smoke inhalation: a histometric study in rats.

PURPOSE: This study investigated the influence of cigarette smoke on bone healing around titanium implants placed in rats. MATERIALS AND METHODS: After administration of anesthesia, the tibia surface was exposed and screw-shaped titanium implants (4.0 mm in length and 2.2 mm in diameter) were placed bilaterally (1 each side). The animals (n = 32) were randomly assigned to either group 1 (control, n = 18) or group 2 (intermittent cigarette smoke inhalation, n = 14). After 60 days, the animals were sacrificed and undecalcified sections obtained. Bone density (the proportion of mineralized bone in a 500-microm-wide zone lateral to the implant) was measured in the cortical (zone A) and cancellous bone (zone B) areas. RESULTS: In zone A, a slight difference in bone density was noted between the groups (96.18% +/- 1.08% and 95.38 +/- 1.17% in groups 1 and 2, respectively; P > .05) but was not statistically significant. In contrast, bone density was significantly decreased in zone B in the animals that were exposed to cigarette smoke (17.57 +/- 6.45% and 11.30 +/- 6.81% for groups 1 and 2, respectively; P < .05). DISCUSSION: Whether different results would be observed if animals were exposed to cigarette smoke for a longer period of time and/or before implant placement remains to be investigated. CONCLUSION: Although intermittent cigarette smoke exposure may not seriously affect cortical bone density, it may jeopardize bone quality around titanium implants in the cancellous bone area.

Animals↗
PubMed1998

[An experimental study of expediting the early attachment of human gingival epithelial cells to titanium with laminin].

Using in vitro culture model, the attachment of human gingival epithelial cells to laminin-coated pure titanium was studied. The average numbers of attached cells on different surface of titanium with or without laminin were calculated under catoptric fluorescent microscope and were statistically analyzed with factorial design. The results showed that Laminin could expedite the early attachment of human gingival epithelial cells to titanium.

Cell Adhesion↗
PubMedDate not supplied

Cementum formation around a titanium implant: a case report.

Animal studies have shown that a periodontal ligament may be produced around a titanium implant when it is in contact with fractured and retained roots. Formation of cementum and attachment connective tissue around titanium implants confirms that cementum progenitor cells are located in the periodontal ligament, since cementum and periodontal ligament are present at the implant-root interface, whereas the remainder of the implant, which is not in contact with the root, shows osseointegration. The aim was to evaluate histologically the characteristics of the tissue present between a titanium implant and a retained root, which were subsequently extracted as a result of peri-implantitis. The histologic examination revealed a continuous layer of cementum and numerous cementocytes on the implant surface. No blood vessel or collagen fibers were detected in the periodontal space. In contrast to experimental studies carried out on animals, the lack of connective tissue fibers and the presence of hypercementosis in this specimen could have been caused by the inflammatory process. Furthermore, the extrusive movement of the root might explain the presence of cementum hypertrophy. Further studies are required to establish whether the neoformation of cementum and collagen fibers on an implant in the presence of root residues occurs only in animal models or whether it may also occur in humans.

Adult↗
PubMedDate not supplied

Effect of estrogen replacement and calcitonin therapies on bone around titanium implants placed in ovariectomized rats: a histometric study.

PURPOSE: The aim of the present study was to evaluate whether hormone replacement therapy (HRT) and calcitonin (CT) administration could influence bone healing around implants placed in ovariectomized (OVX) rats. MATERIALS AND METHODS: One screw-type titanium implant was placed bilaterally in OVX rats. The animals were assigned to one of the following groups: group 1 (n = 15), sham surgeries; group 2 (n = 15), OVX rats; group 3 (n = 14), OVX rats administered CT 4 days/week (16 IU/kg); group 4 (n = 14), OVX rats administered 17beta estradiol daily (20 microg/kg). After 60 days, the animals were sacrificed and undecalcified sections obtained. Bone-to-implant contact (BIC) and bone area (BA) around the implants were determined separately for the cortical (zone A) and cancellous (zone B) bone areas. RESULTS: In zone A, intergroup analysis did not reveal a significant difference regarding BIC. In contrast, the HRT group (group 4) presented greater BA than groups 2 and 3 (P < .05). Data from zone B revealed that HRT eliminated the negative effect of the ovariectomy on BIC and BA (P < .05), while CT had no effect (P > .05). DISCUSSION: It was the first study to evaluate and demonstrate the impact of HRT and CT on bone around titanium implants in an estrogen-deficient model. CONCLUSION: Within the limits of the present study, it may be concluded that HRT may prevent the influence that estrogen deficiency exerts on bone healing around titanium implants.

Analysis of Variance↗
PubMed1999

[New high strength titanium alloy Ti-Zr for dental use].

OBJECTIVE: To develop a new titanium alloy which is suitable for prosthodontic use. METHODS: According to the mechanical properties of Co-Cr alloy and type IV dental gold alloy, a new titanium alloy Ti-Zr was developed. RESULTS: The datas of tensile strength(sigma b = 795 MPa, sigma 0.2 = 657 MPa, delta = 22%, E = 100 GPa) and hardness (249 HK) were collected. The microstructure showed a fine crystal grains. CONCLUSION: The new titanium alloy Ti-Zr is suitable for dental use.

Dental Alloys↗
PubMed2001

[Transverse deflection study of casted titanium zirconium alloy for dental clinic use].

OBJECTIVE: The aim of this study was to obtain the reasonable thickness of Ti-Zr alloy used for denture base material. METHODS: According to the "Revised ADA Specification No. 12 for denture base polymers", the transverse deflection tests of Ti-Zr alloy after casting were performed. Pure titanium, Ti-6Al-4V alloy and Co-Cr alloy were examined as the control. Three groups of wax patterns with different thickness were designed. Ti-Zr alloy, pure titanium and Ti-6Al-4V alloy were casted into molds at 300 degrees C, which were made of zircon (ZrO2.SiO2) investment, using a casting machine (China), with a program of vacuum, pressure and centrifuge casting. Co-Cr alloy was casted by normal method in clinic. The transverse deflections of these four alloys castings with three different thicknesses were measured using a transverse testing machine. RESULTS: When the thickness is 0.65 mm for Ti-Zr alloy, pure titanium and Ti-6Al-4V alloy, and 0.57 mm for Co-Cr alloy, the transverse deflections could satisfy the requirement. CONCLUSION: The transverse deflection is one of the key indexes for evaluating the ability of dental material to bear biting forces. The reasonable thickness of Ti-Zr alloy used as denture base material is 0.65 mm.

Dental Alloys↗
PubMed1998

[Surface treatments for dental titanium castings].

Because pure titanium is highly reactive at high temperature, its casting surface is easily coated with a thick contaminated layer that affects its physical and chemical properties, and consequently a stable superficial oxide membrane develops in the presence of air or water even at room temperature, which makes the surface discolored. Therefore, surface treatments for pure titanium castings are more important than those for other dental alloy castings. This article reviews the methods of surface treatments for dental titanium castings in four aspects: physical finishing, chemical finishing, electro-chemical finishing and surface modification technology.

Dental Casting Investment↗
PubMed2002

[A study of tarnish induced by Streptococcus sobrinus serotype g on Co-Cr, Ni-Cr and casting titanium alloys].

OBJECTIVE: The objective of this study was to investigate the tarnish induced by Streptococcus sobrinus serotype g on Co-Cr, Ni-Cr and casting titanium alloys. METHODS: Co-Cr, Ni-Co and casting titanium alloys were respectively machined into a size of 10 mm x 10 mm x 1 mm in tablets, and totally 90 specimens with 30 of each were prepared for the test. The 30 specimens of each alloy were randomly and equally divided into three subgroups, including the blank control group, the media control group and the inoculated media group. Under the aerobic condition, the surfaces of the sucrose agar media were inoculated with Streptococcus sobrinus serotype g. The labeled sterile specimens were placed on the surface of the media for 10 weeks. The specimens were changed to a new sucrose media with bacteria each week. The specimens were removed after 10 weeks of incubation, immersed in 0.05% glutaraldehyde solution to eliminate AaY4, rinsed with distilled water. After 2 weeks, the specimens were removed and observed visually or examined by MINOLTA CR-100 color apparatus. RESULTS: Compared with the blank control, the control media without bacteria did not influence the alloy specimens (P > 0.05). Streptococcus sobrinus serotype g caused tarnish on specimens. There was significant difference between the control media group and the blank control group with inoculated media group on all the specimens (P < 0.05). CONCLUSION: Streptococcus sobrinus serotype g affects the color of Co-Cr, Ni-Cr and casting titanium alloys, but the color does not change from yellow-green range to red-yellow range.

Chromium Alloys↗
PubMed2001

[Biological assessment of sintered titanium alloy for dental crown and bridge by means of slip casting].

OBJECTIVE: To evaluate the biological safety of sintered titanium alloy for dental crown and bridge, and provide a sound scientific basis for dental clinical practice. METHODS: A series of tests, including acute toxicity test, cytotoxity test (agar overlay), sensitization test, oral mucous membrane irritation test, haemolysis test and micronucleus test were conducted to examine the dental crown/bridge-used titanium alloy which is processed with vacuum-sintered powder metallurgy. RESULTS: The haemolysis rate of this material was 2.21% (less than 5%), an index of good blood compatibility. Cytotoxic effect was not observed in cell culture, nor was toxic effect observed in mouse toxicity test. Local mucous membrane irritation reaction was not found. No potential mutagenicity of this material was noted. CONCLUSION: Dental crown/bridge-used titanium alloy material is of reliable was noted biological safety in dental clinical application.

Animals↗
PubMed2000

The flexibility of titanium clasps compared with cobalt-chromium clasps.

Retention of a partial denture depends on the amount of undercut engaged on an abutment tooth and the flexibility of the clasp. Flexibility is influenced by clasp length and the denture base material. Titanium clasps are purported to have greater flexibility than cobalt-chromium cast clasps which should enable them to engage deeper undercuts or be used where shorter clasp arms are needed such as on premolar teeth. This study investigated the flexibility of cast titanium clasps with three commonly used cobalt-chromium clasps through comparative measurements of their tip deflections and yield strengths. The results showed that the titanium clasps were significantly (P < 0.05) more flexible than the cobalt-chromium clasps. However, all four materials were found to be flexible enough to engage an undercut of 0.25 mm without exceeding their yield strengths.

Chromium Alloys↗
PubMed2003

Preparation and osteocompatibility of hydroxyapatite coated on titanium from the reaction of sputtered CaO and vaporized P2O5.

Hydroxyapatite (HA) and other calcium phosphates were synthesized on titanium plates by a solid-gas state reaction of sputtered CaO and vaporized P(2)O(5). The calcium phosphates formed were HA, beta-tricalcium phosphate (beta-TCP; Ca(3)(PO(4))(2)), beta-calcium pyrophosphate (beta-PYR; Ca(2)P(2)O(7)), and beta-calcium metaphosphate (beta-MET; Ca(2)(PO(3))(2)). Their formation depended on the ratio of the sputtered CaO and the reacting P(2)O(5). For a mole ratio of CaO/P(2)O(5)=4 (Ca/P=2), an HA film was synthesized. The surface roughness increased by over seven times after the solid-gas state reaction from Ra = 0.16+/-0.02 microm (for the CaO film) to Ra = 1.15+/-0.25 microm (for the reacted film). The synthesized HA film-coated titanium plates and control non-coated titanium plates were implanted in the femora of two dogs for a period of two, four and 12 weeks, and observed using a soft X-ray radiograph and histological sections. New bone formation was observed without any connective tissue at four weeks around the HA film, whereas over the 12 week experimental period, there was no new bone formation around the control and connective tissue was observed over all periods, reaching a thickness of more than 200 microm at 12 weeks.

Animals↗
PubMed2002

In vitro cytocompatibility studies of Diamond Like Carbon coatings on titanium.

Diamond like carbon (DLC) films were deposited on to titanium (Ti) substrates by Plasma Enhanced Chemical Vapour Deposition (PECVD) process. The quality of the films were checked by Raman spectra and nano-hardness tests. The cytocompatibility of titanium and DLC coated titanium were studied using continuous cell lines of mouse fibroblast cells ( L-929), Human Osteoblast cells (HOS) and primary human umbilical cord vein endothelial cells (HUVEC). The cellular responses to the materials were assessed both quantitatively and qualitatively. The adhesion and spreading of cells on materials were compared using Ti as a control. Present study indicates an improved cytocompatibility of DLC coated Ti in comparison to bare Ti.

Animals↗
PubMed2002

A new porous titanium-nickel alloy: part 2. Sensitization, irritation and acute systemic toxicity evaluation.

Porous titanium-nickel (PTN) represents a new biomaterial with orthopedic applications as a long-term implant. Because of its nickel content, PTN was tested for its potential to stimulate sensitization, irritation, and systemic toxicity reactions after semi-physiological extraction. In order to do so, an in vivo biocompatibility evaluation was performed following three ISO-standardized methods using accepted animal models for immunity testing: the classical skin sensitization assay (Buehler patch test) in guinea pigs, the rabbit intracutaneous test, and the systemic injection test in mice. The Buehler patch test in guinea pigs revealed no significant change in skin reactions such as erythema or swelling between the induction and the challenge period. In the rabbit intracutaneous irritation test, no irritation or sensitization reactions were observed in saline-extracted PTN samples. Negligible to slight irritation was observed at some of the sites involving PTN samples extracted in cottonseed oil, however the resulting primary irritation index was similar to the one elicited by the blank solution itself. Finally, no toxic symptoms were observed with any of the mice injected with porous titanium-nickel extracts during the acute systemic toxicity test. Based on the above results, porous titanium-nickel is considered to be a non-sensitizing, non-irritant, and non-toxic biomaterial for medical applications.

Administration, Cutaneous↗
PubMedDate not supplied

Comparisons of precision of fit between cast and CNC-milled titanium implant frameworks for the edentulous mandible.

PURPOSE: The purpose of this study was to investigate and compare the precision of fabrication in repeatqdly produced computer numeric controlled (CNC)-milled frameworks with consventional castings, and to analyze the distortion from application of different veneering materials. MATERIALS AND METHODS: Twenty identical titanium frameworks were fabricated by means of a CNC milling technique for the same master model. Five conventional frameworks were cast as a control group to the same model. The frames were measured with regard to fit in a coordinate measuring machine linked to a computer. Measurements were made during different stages of handling of the titanium framework, and after veneering materials had been applied. RESULTS: The CNC frameworks showed a statistically better fit and precision of fabrication compared to conventional castings (P < .05). The application of veneering material did not statistically affect the fit of the titanium frameworks (P > .05). CONCLUSION: It is possible to fabricate implant-supported frameworks by means of the present CNC technique with a very high precision and repeatability.

Acrylic Resins↗
PubMed2003

[Influence of an Er:YAG laser on the surface structure of titanium implants].

In addition to conventional treatment modalities (mechanical and chemical), the use of lasers has been proposed for cleaning and detoxification of implant surfaces. The aim of the present clinical investigation was (1) to evaluate the effects of an Er:YAG laser on the surface properties of titanium implants in vivo and (2) to determine the effectiveness of this treatment modality for subgingival calculus removal. This investigation was conducted on eight implants of two patients, considered for explantation due to severe peri-implantitis inflammation. Immediately before explanatation, six implants were instrumented subgingivally with an Er:YAG laser (100 mJ/pulse and 10 Hz). Two implants served as a control. All titanium implants were examined using scanning electron microscopy by one calibrated and blinded examiner. In comparison to the untreated control group, non-surgical instrumentation of titanium implants with an Er:YAG laser resulted in an effective removal of subgingival calculus without leading to any thermal damages. However, all samples of the test group revealed amounts of residual debris which should be taken into account under clinical conditions.

Decontamination↗
PubMed2003

[The effect of root canal preparation with nickel-titanium rotary instruments in reducing post-operative pain].

OBJECTIVE: To examine the effect of nickel-titanium rotary instruments in reducing post-operative pain. METHODS: 95 molars with pulpal and/or periapical involvement were randomly assigned to two groups for root canal preparation. One group was treated with ProFile nickel-titanium rotary instruments; the other was treated by using stainless steel hand files-FlexoFile. The incidence and degree of post-operative pain after root canal preparation in the two groups were recorded. RESULTS: In ProFile group, the incidence of post-operative pain was 27.7%, while 62.5% of the teeth developed post-operative pain after hand preparation. The difference between two groups was statistically significant (P < 0.01). CONCLUSION: Root canal preparation on molars with stainless steel hand files resulted in relatively high incidence of post-operative pain. Mechanical preparation using ProFile nickel-titanium instruments generated less post-operative pain and discomfort.

Adult↗
PubMed2003

[Clinical study of pure titanium membranes in oral implant surgery].

OBJECTIVE: To evaluate predictability and treatment outcome of the pure titanium membranes in bone defects around endosseous implants. METHODS: 81 patients and 92 dental implants were included in this study. The defects around implants were filled with bone grafts and Bio-Oss, and then covered by titanium membranes. 6 - 10 months later, all of the membranes were removed. RESULTS: 5 patients showed complications in soft tissue healing with exposure of the membranes. Bone defects around 89 implants were successfully covered with new regenerated bone. CONCLUSIONS: Pure titanium membranes show excellent biocompatibility, exhibit good mechanical properties, avoid grafts displacement, ingrowth of connective tissue and contour collapse.

Adult↗
PubMed2003

[Animal model study of guided bone tissue regeneration around implant by titanium membrane].

OBJECTIVE: To evaluate the titanium membrane-guided bone tissue regeneration around implant and HA granules. METHODS: Three adult cross-bred dogs were used. In the animal's mandible, man-made bone damaged regions (diameter 6.5 mm, depth 4 mm) being concentric with the implant holes were prepared. The implants were planted into the holes and were rendered to separate the damaged regions into two parts with two titanium sheets. One part was filled with HA granules while the other with nothing. Histological evaluation was done at 4, 8 and 12 weeks of implantation. RESULTS: The bone around the implants grew obviously at 4 weeks; the bone grew more and the structure of the bone was similar to that of the normal bone at 12 weeks. CONCLUSION: As a new type of GTR materials, titanium membrane can keep the existence of spaces underneath. HA granules can give guiding effects to bone tissue regeneration.

Animals↗