Titanium Substructure Research Articles

Comparison of the bond strength of porcelain to titanium substructure made by EBM or Milling method

Comparison of the bond strength of porcelain to titanium substructure made by EBM or Milling method

The effects of current production techniques on the surface roughness, oxide layer thickness and porcelain bond strength of cobalt-chromium and titanium substructures

Aim: This study aimed to evaluate the oxide layer, surface roughness, and bond strength with porcelain of cobalt-chromium (Co-Cr) and titanium (Ti) substructures produced using casting, milling and selective laser sintering techniques.
 Methodology: A total of 180 disc-shaped metal samples with a diameter of 1 cm and a thickness of 3 mm were produced. The samples were divided into six groups (n=15) according to the technique used to produce the metal substructures—casting, milling, and SLS—and the chemical composition of the metal substructure—Co-Cr and Ti. Then roughness averages (Ra) of the sample surfaced were calculated with a contact-type profilometer. Nondestructive energy-dispersive X-ray was performed to ensure that the layer displayed in contrast was the oxide layer, and the average oxide layer thickness was calculated from scanning electron microscope images. Metal-porcelain complexes were subjected to shear bond strength test and failure types were noted. Two-way multivariate analysis of variance (MANOVA) was used to compare oxide layer thickness, surface roughness, and shear bond strength according to the metal and production technique, and Tukey’s honestly significant difference (HSD) test was used for multiple comparisons of the main effects.
 Results: Two-way MANOVA revealed that the metal and technique used in the substructure production had significant effects on surface roughness, oxide layer thickness and shear bond strength (p < 0.001). Ti groups exhibited thicker oxide layer formation than Co-Cr groups. Low surface roughness values were observed in the milling groups. The highest shear bond strength value (53.8 MPa) was observed in the Co-Cr group produced by casting, while the lowest value (32.2 MPa) was obtained in the Ti group produced by casting.
 Conclusion: It should be kept in mind that there is no ideal production technique and that the effects of the production technique differ depending on the metal used.
 
 How to cite this article: Ünalan Değirmenci B, Ersoy NM. The effects of current production techniques on the surface roughness, oxide layer thickness and porcelain bond strength of cobalt-chromium and titanium substructures. Int Dent Res 2021;11(3):129-39. https://doi.org/10.5577/intdentres.2021.vol11.no3.1
 
 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Effect of retention design of artificial teeth and implant-supported titanium CAD-CAM structures on fracture resistance.

BackgroundFor implant-supported hybrid prostheses, high mastication forces and reduced acrylic resin thickness over a metal substructure often cause failures arising from tooth or resin fractures. To assay fracture resistance of artificial teeth and resin in implant-supported hybrid prostheses in relation to the titanium structure and retention design supporting teeth.Material and Methods40 specimens bearing incisors were divided into four groups according to the titanium structure supporting the teeth and the type of load force applied: Group I (Control; n=10): Application of static loading to ten incisors set over a metal structure with internal retention. Group II (Control; n=10): Application of static loading to ten incisors set over a metal structure with external retention. The remaining study specimens (n=20) were subjected to 120,000 masticatory and thermal cycles in a chewing simulator. Afterwards, static loading was applied until the point of fracture using an Instron machine. Group III (Study; n=10): Application of dynamic and static loading to ten incisors set over a metal structure with internal retention. Group IV (Study; n=10): Application of dynamic and static loading to ten incisors set over a metal structure with external retention. Data obtained for the four groups was analyzed and compared, determining the type of fracture (cohesive or adhesive) using a reflected light microscope.ResultsStatistical analysis confirmed that there were significant differences in fracture resistance between the four groups. External retention was found to have more fracture resistance than the internal retention.ConclusionsHybrid prostheses with titanium substructures and external retention obtained significantly better results than samples with internal retention. Key words:Chewing simulator, thermocycler, fatigue, implant-supported hybrid prosthesis, acrylic teeth, fracture, metal structure design.

Airborne-particle abrasion parameters on the quality of titanium-ceramic bonds

Statement of problemAirborne-particle abrasion of titanium is a clinically acceptable method of surface preparation. It is crucial to know the effectiveness of bond strength between the metal substructure and the veneering ceramics after this kind of surface treatment. PurposeThe purpose of this study was to determine how the particle size of the abrasive material and pressure affected treated surfaces and the strength of titanium-ceramic bonds. Material and methodsDisks made of titanium (Tritan CpTi grade 1, Dentaurum, 99.5% Ti) were treated in an airborne-particle abrasion process with 50, 110, and 250 μm aluminum oxide (Al2O3) at pressures of 0.2, 0.4, and 0.6 MPa. To characterize the treated surfaces, the following values were measured: roughness, free surface energy, and the quantity of abrasive particles attached to the surface. Subsequently, the strength of the metal-ceramic bond was determined. Apart from the strength tests, fractures were observed to determine the character and fracture location in the course of the strength tests. The results of the experiment were analyzed with 2-way ANOVA and the Tukey HSD test (α=.05). ResultsBoth the pressure and the particle size of Al2O3 used in the airborne-particle abrasion affected the strength of the titanium-ceramic bond (P<.05). A statistically significant difference was found between the group subjected to airborne-particle abrasion under a pressure of 0.4 MPa with 110-μm Al2O3 particles and the other experimental groups (P<.05). ConclusionThis study demonstrates that the highest bond strength between a ceramic and titanium substructure can be achieved after airborne-particle abrasion at an angle close to 45 degrees with 110-μm Al2O3 particles under 0.4 MPa of pressure.

Transition from a fixed implant dental prosthesis to an implant overdenture in an edentulous patient: A clinical report

The lack of planning before implant placement and restoration in edentulous patients can lead to a number of problems. Prosthodontists are often faced with the challenge of re-treating patients who have only recently been treated. Although many reports discuss retreatment by fabricating all new prosthetic components, few discuss salvaging parts of the patient's existing prosthesis. This report details the treatment of an edentulous patient who presented with an implant-retained fixed dental prosthesis in the maxillary arch and no opposing prosthesis. The transition from an implant-retained fixed dental prosthesis to a removable implant- and tissue-supported overdenture that uses the patient's existing computer-aided design/computer-aided manufacturing milled titanium substructure is described.

Metal–ceramic-fixed dental prosthesis with CAD/CAM-fabricated substructures: 6-year clinical results

The aim of this study was to evaluate the clinical performance of fixed dental prostheses (FDPs) with computer-aided design (CAD)/computer-aided manufacturing (CAM)-fabricated titanium substructures veneered with low-fusing porcelain after 6years. Thirty-one FDPs for 23 patients were fabricated. The frameworks were designed and milled using an early version of a dental CAD/CAM system. Checkups were performed annually. Complications totaled ten porcelain fractures, one substructure fracture, and one biologic failure. The success rate was calculated at 58.6% and the survival rate at 88% (Kaplan-Meier analysis). The clinical performance of the described technique for FDPs with titanium substructures was poor. Therefore, the presented concept cannot be recommended. CAD/CAM-fabricated titanium substructures veneered with the powder build-up technique showed poor clinical outcome after 6years.

Maxillary implant-supported bar overdenture and mandibular implant-retained fixed denture using CAD/CAM technology and 3-D design software: A clinical report

The implant-supported bar overdenture and the implant-retained fixed complete denture are appropriate treatment choices for patients with inadequate bone volume in the posterior maxilla and mandible, respectively. Computer-aided design/computer-aided manufacturing (CAD/CAM) technology has broadened the scope and application of those treatment options, allowing for prosthodontically-driven implant placement and ideal substructure design for optimal esthetics and biomechanics. This report describes the fabrication of a maxillary implant-supported milled titanium bar with attachments and an overdenture, and a mandibular implant-retained fixed complete denture with milled titanium substructure.

A Gross Error Occurred When Treatment Planning a Guided Surgery Case

This case history illustrates how a mistake, when manufacturing the radiographic guide, can duplicate itself when placing the implants through the surgical template. This led to a disastrous aesthetic result. This case history also illustrates yet another reason for constructing a provisional restoration in the first instance before proceeding to the final restoration using a titanium substructure or bonded bridgework.

Immediate facial rehabilitation in cancer patients using CAD–CAM and rapid prototyping technology: a pilot study

This study describes the workflow in a procedure to create a provisional facial prosthesis for cancer patients using digital and rapid prototyping technologies without the need for supporting craniofacial implants. An integrated workflow procedure aimed at the construction of provisional silicone prosthesis was used to rehabilitate a facial disfigurement in a patient who had undergone ablative surgery of the midface. A laser scan of the defect was obtained, and a digital model of the patient's face was constructed using virtual mirroring of the healthy side and referencing the "Nose Digital Library." The missing volume of the face was reconstructed, and a rapid-prototyped mold was devised to process the silicone prosthesis. A provisional eyeglasses-supported prosthesis designed with a CAD/CAM-projected titanium substructure was connected using the micro-components of implant prosthetic devices. The workflow described herein offers a viable procedure for quickly restoring facial defects by means of provisional prosthetic rehabilitation.