Titanium Restorations Research Articles

PEEK-Polymer for Dental Implants: A Concise Review

The biomaterials applicable in dental implantology, or implantology generally, are subject to specific requirements, namely biocompatibility, osseointegration, resistance to fracture/ oxidative degradation/ long-term compressive stress/ hydrolisis in boiling water, suitable morphology, suitable physical properties (including mechanical properties), aesthetics, etc. When selecting a suitable material for dental implants, it is also necessary to consider the patient s current health condition and possible complications when placing titanium implants and alloys. If there is a risk of an allergic reaction or hypersensitivity to any of the components of the metal prosthesis, the placement of a semi-crystalline thermoplastic implant - called polyetheretherketone, abbreviated PEEK - is a possible option. Such a wide range of stiffness means that PEEK formulations can be produced with modulus values similar to cortical bone. PEEK is classified as a High Performance Polymer of polymer pyramide (such as Polysulfones polybutylene terephthalate). PEEK can be applied for dental abutment and dental body. This article summarises basic information on the structure and properties of PEEK polymer, advantages/ disadvantages (compared to metal - titanium restorations), application and general information from the examined field.

Bonding of resin luting materials to titanium and titanium alloy.

Recently in Japan, due to the increased prices of palladium and gold, cast titanium restorations have been included in the Japanese national health insurance system. The purpose of this review was to survey the available literature on titanium bonding systems, focusing on the adhesive monomer in the luting agent in order to expand the application of resin-bonded fixed prostheses made of titanium or titanium alloys. It was found that adhesive monomers are effective for bonding to titanium, and provide results equal to the procedures of silanization and tribochemical silica coating. A primer or a luting agent, including 10-methacryloyloxydecyl dihydrogen phosphate (MDP), methacryloyloxyalkyl thiophosphate derivative (MEPS), 6-methacryloxyhexyl phosphonoacetate (6-MHPA), and 4-methacryloyloxyethl trimellitate anhydride (4-META) promotes bonding characteristics between titanium and the resin material.

Biodegradable Polymer/TiO2 Nanotubes Loaded Roxithromycin as Nanoarray Capsules for Long-Lasting Antibacterial Properties of Titanium Implant

Bacterial infection is one of the main reasons for the clinical failure of oral titanium restorations. In this study, biodegradable polymer/TiO2 nanotube nanoarray capsules were constructed on a titanium substrate surface to locally deliver drugs for long-lasting antibacterial properties. Anodization was applied to prepreparation TiO2 nanotube array film on titanium substrate, and then, the upward opening TiO2 nanotubes were sealed with biodegradable polymer (chitosan and polyethylene glycol) through electrochemical deposition. Scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) were used to analyze the characterization of this system. The drug release characteristics and the antibacterial activity demonstrated that the polymer coating significantly reduced burst release and enhanced lasting antibacterial properties. The nanoarray capsules still preserved integrity with a little degradation after 2 days. The strategy described herein provides a versatile route for designing targeted drug delivery systems in orthopaedical and other biomedical fields.

Preliminary study on the elimination of artifacts of five kinds of dental prosthetic materials by energy spectrum CT multi-material artifact reduction technology

Objective: To investigate the effect of the multi-material artifact reduction (MMAR) algorithm of spectral CT in reducing the beam hardening artifacts in dental restoration material. Methods: Three-unit fixed bridge restorations were fabricated on the first to third molars in pig jaw. Gold alloy, zirconia, cobalt chromium alloy, nickel chromium alloy and pure titanium were used as materials for these fixed bridges. After restoration delivery, the pig jaw was scaned using energy spectrum CT machines. Images in regular 120 kVp scan mode were used as conventional group, and reconstructed single-energy horizontal images of 80, 90, 100, 110, 120, 130 and 140 keV in energy spectrum scanning mode were used as energy spectrum group, and reconstructed images applied MMAR technology in energy spectrum scanning mode were used as energy spectrum MMAR group. Each group was scanned 10 times to measure CT value and noise of muscles around dental prosthetic materials and adjacent non-artifact layers. Artifact index was calculated. Two radiologists scored the image quality of each group subjectively. Kruskal Wallis rank sum test was used to compare the difference of image noise, artifact index and subjective score among the control group and the best keV condition in the energy spectrum group and the energy spectrum MMAR group. Results: The image noise of energy spectrum group and energy spectrum MMAR group decreased gradually with the increase of single energy level. The artifact index of pure titanium restorations in conventional group, energy spectrum group and energy spectrum MMAR group were 71.0±8.0, 21.4±2.7 and 14.7±2.7 respectively, and these values were significantly lower than those of other materials in the same group (P<0.05). The subjective image quality scores in energy spectrum MMAR group were as follows: 3.0±0.2 for gold alloy, 4.3±0.5 for zirconia, 3.0±0.4 for cobalt chromium alloy, 3.1±0.4 for cobalt chromium alloy, and 4.6±0.5 for pure titanium. These scores were significantly smaller than those in the conventional group (P<0.05). There was no significant difference in noise between energy spectrum group and energy spectrum MMAR group (P>0.05), and the noise values in energy spectrum group and energy spectrum MMAR group were significantly lower than that in the conventional group (P<0.05). Conclusions: Artifacts of pure titanium is minimal. Energy spectrum CT combined with MMAR technology can effectively reduce the artifacts of gold, zirconia, cobalt-chromium alloy, nickel-titanium alloy and pure titanium. This technique can be used as an effective method to remove artifacts of dental prosthesis.

Evaluation of the Effect of Fluoride-containing Luting Cements on Titanium and Its Effect on the Shear Bond Strength.

Context:The most appropriate luting agent for titanium crowns is yet to be determined. Commonly used cements for luting titanium restorations give off leachable ions which may cause surface interaction with the titanium.Aims:The purpose of this study was to determine the shear bond strength of four grades of commercially pure titanium and Ti 6Al 4V with different cements and to examine for any surface physical changes.Settings and Design:The three luting cements, i.e., zinc polycarboxylate cement, glass ionomer cement, and zinc phosphate cement, were used to evaluate their effect on titanium. Ni Cr was used as a control.Methods and Material:The metal rods were milled to discs of 6 mm diameter and 4 mm height. Freshly extracted maxillary first molars, mounted in resin blocks, were sliced horizontally at occlusal third of the tooth. The discs were cemented to the sliced surface of the tooth with the three luting cements. The models were subjected to the shear bond strength test. Statistical analysis used: The data collected were analyzed statistically with one way ANOVA. A representative specimen of each group was observed under a scanning electron microscope.Results:The mean values ranged from 0.31 to 15.6 MPa. The shear bond strength values of the zinc polycarboxylate cement group were significantly high (P < 0.05). Corrosion of the titanium alloy luted with zinc polycarboxylate cement was observed.Conclusions:Cementation with zinc polycarboxylate cement provided high shear bond strength, but showed corrosion on titanium.

In vivo evaluation of the exposure to aluminium, cobalt, chromium, copper, nickel, titanium and vanadium in oral mucosa cells from orthodontic patients with mini-implants by Inductively coupled plasma-mass spectrometry (ICP–MS)

Statement of problem. The biocompatibility of titanium has been well documented, but clinical outcomes of ceramic-veneered titanium restorations were not conclusive. Purpose. The study presents the results of a 5-year clinical study of individual crowns and fixed partial dentures (FPDs) veneered with a low-fusing ceramic of the Procera system. Material and methods. All patients at one clinic who required crowns or FPDs during a 2-year period were invited to participate. A total of 260 patients received 333 ceramic-veneered Procera restorations (242 single crowns and 91 FPDs). Clinical registrations were performed annually, and the restorations were evaluated according to the California Dental Association rating system. At the 5-year follow-up, 198 (76%) patients were examined. Most of the loss of patients could be explained. Results. Practically all Procera restorations were judged as satisfactory both at baseline and follow-up examinations. One artificial crown and 1 FPD were remade because of extensive fractures of ceramic veneers. Two FPDs had fractures of a soldered joint, but only 1 FPD was replaced. Some minor complications occurred, such as small porcelain fractures that could be polished (6% of single crowns, 13% of FPDs) and or loosened restorations that were recemented. Other recorded complications were not related to the Procera system but to dental caries, loosened posts and cores, and root fractures. Conclusion. Clinical outcomes over a 5-year period for ceramic-veneered titanium restorations with the Procera system were favorable. (J Prosthet Dent 2000;84:514-21.)

Effect of fluoride from glass ionomer on discoloration and corrosion of titanium

The objective of the study was to examine the effects that fluoride ions released from different dental glass ionomer cements may have on titanium. The study included determination of the amounts of released ions and measurement of the color changes on titanium plates cemented with four kinds of commercial glass ionomer cements due to immersion of such “sandwich specimens” in 1% saline (NaCl) solution. The discoloration of titanium in the presence of glass ionomer cements was observed. In addition, for specimens cemented with two of the cements titanium ions were found in the solution after immersion. The results of the present study show that a low concentration of released fluoride ions and other elements from glass ionomer cements may cause aesthetic problems of discoloration of titanium restorations and appliances.

An In Vitro Comparison of Vertical Marginal Gaps of CAD/CAM Titanium and Conventional Cast Restorations

To determine if there was a significant difference between the vertical marginal openings of cast restorations, computer-aided design, and computer-aided machining restorations. Ten working dies were created from a single master die and used to fabricate ten restorations in each of the following groups: computer-aided design/computer-assisted machining (CAD/CAM), WAX/CAM, and WAX/CAST. The CAD/CAM titanium restorations were fabricated using the scanning and crown design modules of the KaVo Everest system. The WAX/CAM titanium restorations were fabricated using the double scan technique with the KaVo Everest system. The WAX/CAST high noble copings were fabricated using the conventional lost wax casting technique. The restorations were seated on the master die, and high-resolution digital photographs were made of the marginal area on all four sides. The vertical marginal opening was then measured using a calibrated digital software program. One-way ANOVA and Tukey's post hoc tests were used to determine the presence of statistically significant differences. The vertical margin openings were CAD/CAM: 79.43 +/- 25.46 microm; WAX/CAM: 73.12 +/- 24.15 microm; WAX/CAST: 23.91 +/- 9.80 microm. There was a statistically significant difference between the WAX/CAST group and the remaining groups. There was no difference between the vertical marginal gaps of the CAD/CAM and WAX/CAM. The WAX/CAST technique resulted in smaller vertical marginal gaps than either CAD/CAM or WAX/CAM.

Plaque, gingival health and post-operative sensitivity in titanium inlays and onlays: a randomized controlled clinical trial

Objectives: Few clinical data on the use of titanium for restorative appliances are available. The aim of this study was to clinically evaluate titanium restorations compared to gold alloy restorations with regard to plaque, gingival health and post-operative sensitivity. Methods: In 54 patients, 99 titanium restorations were placed. The control group comprised 56 patients with 96 high gold alloy restorations. The material was chosen by random. Each patient received one or two Class II restorations. Plaque Index (Silness and Löe, 0–3), Gingival Index (Löe and Silness, 0–3), and post-operative sensitivity (1–4, 1=none) were rated at 2 weeks, 3 months, 6 months, 12 months, and 18 months, post-operatively. Results: The mean plaque scores ranged from 0.89 to 0.99 in the titanium group, and from 0.88 to 1.04 in the gold group. The mean gingival scores ranged from 0.91 to 1.07 in the titanium group, and from 0.82 to 0.99 in the gold group. The mean plaque and gingival scores of the titanium and gold group did not differ significantly at any visit ( P>0.05). To evaluate post-operative sensitivity, patients with one MOD restoration each were included, resulting in 46 titanium and 44 high gold restored teeth. Mean values of the post-operative sensitivity scores in the titanium group were significantly higher than in the gold group ( P<0.05). The restoration material was found to be the dominating variable with regard to post-operative sensitivity, which was not influenced by age, sex and the application of calcium hydroxide liner. Conclusions: It is concluded that neither higher plaque scores nor adverse effects on gingival health are to be expected in titanium restorations.

Prospective clinical 5-year study of ceramic-veneered titanium restorations with the procera system

Statement of problem. The biocompatibility of titanium has been well documented, but clinical outcomes of ceramic-veneered titanium restorations were not conclusive. Purpose. The study presents the results of a 5-year clinical study of individual crowns and fixed partial dentures (FPDs) veneered with a low-fusing ceramic of the Procera system. Material and methods. All patients at one clinic who required crowns or FPDs during a 2-year period were invited to participate. A total of 260 patients received 333 ceramic-veneered Procera restorations (242 single crowns and 91 FPDs). Clinical registrations were performed annually, and the restorations were evaluated according to the California Dental Association rating system. At the 5-year follow-up, 198 (76%) patients were examined. Most of the loss of patients could be explained. Results. Practically all Procera restorations were judged as satisfactory both at baseline and follow-up examinations. One artificial crown and 1 FPD were remade because of extensive fractures of ceramic veneers. Two FPDs had fractures of a soldered joint, but only 1 FPD was replaced. Some minor complications occurred, such as small porcelain fractures that could be polished (6% of single crowns, 13% of FPDs) and or loosened restorations that were recemented. Other recorded complications were not related to the Procera system but to dental caries, loosened posts and cores, and root fractures. Conclusion. Clinical outcomes over a 5-year period for ceramic-veneered titanium restorations with the Procera system were favorable. (J Prosthet Dent 2000;84:514-21.)

Margin quality of titanium and high-gold inlays and onlays — a clinical study

Objectives. Unalloyed titanium may be an economical substitute for gold alloys. The purpose of this study was to evaluate the suitability of unalloyed titanium as an alternative to gold alloys for posterior inlay and onlay restorations. Methods. Fifty-four patients received 99 titanium restorations, 56 patients 96 gold alloy restorations. All titanium restorations were cast in a vacuum-pressure casting machine. Two weeks after insertion the clinical margin integrity was evaluated by replica technique. The maximum marginal gaps were assessed under the optical measuring microscope. The two tailed t-test for independent samples was used for statistical analysis. Results. Accuracy of fit was significantly better in gold alloy than in titanium restorations. Mean maximum marginal gap between restoration margin and tooth structure were 72±18 μm (mean ±S.D.) for titanium and 64±18 μm (mean ±S.D.) for gold restorations. Significance. Though marginal gap widths in titanium restorations did not yet match the gold standard, the data justify the use of titanium as an alternative to gold alloy for inlay and onlay restorations.

Dentists' opinions on aspects of cast titanium restorations

Objectives: The purpose of this paper was to study dentists' opinions regarding aspects of the clinical use of cast titanium restorations. Methods: Since 1988 more than 10000 cast titanium units of crowns and fixed partial dentures have been produced by the only dental laboratory that produces cast titanium restorations in Norway. A questionnaire on the clinical behaviour of such restorations was mailed to all 72 dental practitioners who were recorded in the computer file of this laboratory. Results and conclusion: In the opinion of the 64 dental practitioners who completed the questionnaire, cast titanium is a useful supplement to conventional casting alloys, particularly because of its favourable cost. It has a satisfactory clinical behaviour, although there may be some problems related to technical and aesthetic aspects.

Controlling coloration for titanium restorations

Controlling coloration for titanium restorations

Clinical performance of machined titanium restorations

In 37 patients 88 titanium restorations were placed during a 1-year period 1990–1991. The 69 crowns and 19 fixed partial dentures comprised 147 prosthodontic units. All restorations were fabricated by duplication milling and electrical discharge machining of pure titanium (Procera Technology, Nobelpharma, Gothenburg, Sweden). Based on the results of clinical follow-up, Kaplan-Meier survivor functions were calculated. The survivor rate of 40 metal crowns and pontics was 100%. In 107 porcelain-fused-to-metal units the 3-year survivor rate concerning removal was 95%. When relating the survival to an intact ceramic veneer, the 3-year survivor rate of porcelain-fused-to-metal units was 84%. The quality of the restorations evaluated by the rating system of the California Dental Association was found to be satisfactory in the vast majority of cases. It can be concluded that machined titanium restorations are suitable for clinical use, although not all problems, especially in the field of metal-ceramics have yet been completely solved.

Dimensional fit of cast titanium restorations

Undersizing of cast Ti crowns has been reported to be a problem. The diameter of standardized, cylindrical crowns was studied in this investigation using a photographic technique and cold moulds. The results show that the dimensional problem can be avoided by selecting a standard phosphate-bonded investment with a sufficiently high thermal expansion coefficient. Appropriate casting conditions with a good vacuum (13.3 Pa) gives only a thin (<10 μm) oxide film and reproducible dimensions of the castings. A ZrO2 coating eliminates or reduces the oxide film and follows the movements of the investment. The diameter of the crown can largely be accounted for by the measured expansion of the investment and thermal contraction of the Ti casting.

Non-cast titanium restorations in fixed prosthodontics.

The problems encountered in casting titanium in dentistry have not been completely resolved. The Procera system forms crowns by means of a combination of spark-erosion and milling. The accuracy of fit was examined before and after ceramic veneering both in vitro and in vivo. Before veneering, on conical surfaces space widths were approximately 53 microns in vitro and 69 microns in vivo. At shoulders and occlusal surfaces, spaces of about 430 microns were measured in vitro and of about 500 microns were measured in vivo. After ceramic veneering, slight increases in space widths could be observed. The metal-ceramic compound was tested by the 3-point bending test (DIN) and the bending test (ISO). The DIN test was satisfactory, but not the ISO test. It is concluded that titanium crowns processed by the Procera System are suitable for clinical usage, if the space widths at shoulders and the occlusal surface and the special requirements of tooth preparation are taken into account.