Machined Surface Implants Research Articles

Bone Contact Around Osseointegrated Implants: A Histologic Study of Acid-Etched and Machined Surfaces

Current literature reports that surface acid etching can improve bone--implant contact (BIC). The aim of this study was to evaluate the differences of BIC between acid-etched (Osseotite) and machined surface implants. Six white New Zealand mature rabbits were used in the present investigation. Each rabbit received two implants, specially made with two surfaces on it (one acid-etched and one machined) into each tibia. A total of 24 implants were inserted. Two animals each were killed at 15, 30, and 60 days after implant placement. Histomorphometry of BIC was statistically evaluated. The acid-etched surfaces showed a greater bone contact percentage than the machined ones during the early phase of healing (15 days), which was not statistically significant. On the other hand, after 30 and 60 days, the differences of BIC between acid-etched and machined surfaces were statistically significant. The acid-etched surface appears to improve BIC at a later stage of healing.

Dental implants – pertinent papers 2002–2003: A personal view

T u c t s r o o a i i s when custom-made bridges and crowns fitted at the time of placement implants is the norm. This paper stresses the importance of careful planning and notes failures associated with bruxism; this harks back to similar warnings in earlier papers about implants. The benefits of accelerated care for patients are clear; we are, however, reminded that this is associated with a slightly higher risk of failure than the traditional approach.

Early Function of Splinted Implants in Maxillas and Posterior Mandibles, Using Brånemark System® Tiunite™ Implants: An 18‐Month Prospective Clinical Multicenter Study

Immediate or early loading of implants placed in maxillas and posterior mandibles has been a concern as bone density is often low in these areas, making it difficult to establish good initial implant stability. By adapting implant design and insertion protocols, however, high initial implant stability may be achieved in these regions. Further, a modified implant surface texture has been proved to help in maintaining stability during the initial healing period. The aim of the present study was to investigate the clinical performance of oxidized titanium implants (TiUnite, Nobel Biocare AB, Gothenburg, Sweden) when used for early function in the maxilla and in the posterior mandible, locations where the bone density often is low. A further aim was to evaluate the marginal bone level at oxidized implants and compare it with that of machined-surface implants used in a previous study. Thirty-one patients were consecutively included in the study, and 37 edentulous areas in maxillas and posterior mandibles were treated. Bruxism and uncontrolled periodontal disease were exclusion criteria. Temporary prostheses were generally placed within 9 days but not after 16 days from implant placement. A previous study applying the same study design and clinical protocol but using machined-surface implants was used for comparisons. Of the 111 implants installed, 1 failed, giving an overall survival rate of 99.1% after 18 months. The prosthesis survival was 100%. The marginal bone resorption was 0.8 mm (standard deviation [SD], 1.0), as opposed to 1.6 mm (SD, 1.3) in the previous study with machined-surface implants, but was not statistically significantly different (p = .10). The present clinical protocol (aiming at high primary stability) and the use of oxidized titanium implants for early functional loading in the maxilla and the posterior mandible resulted in a high implant survival rate and a favorable marginal bone level during a follow-up of 18 months. The difference in marginal bone resorption between the oxidized implants in the present study and the machined implants from a previous investigation with the same study design was not statistically significant.

Clinical evaluation of short, machined-surface implants followed for 12 to 92 months

Purpose Bone resorption following tooth loss often limits the quantity of bone available for implant placement. The purpose of the present study was to evaluate the clinical outcome of 10-mm or shorter machined-surface implants when used exclusively in the treatment of various forms of edentulism. Materials and methods Two hundred sixty-nine screw-type Branemark System implants (Nobel Biocare), 10 mm or shorter, were placed in 111 consecutively treated patients. Of the total, 88.8% were placed in the mandible and 11.2% were placed in the maxilla; 95.2% were used to treat partially edentulous situations, including single-tooth losses, of which 96.6% were in the premolar and molar regions. The patients were followed for periods of 12 to 92 months. Results Of the 269 placed implants, 12 were lost. The overall survival rate was 95.5%. Bone quality 2 and 3 (Lekholm-Zarb classification of 1985) was found in 88.8% of the treated sites. There was no statistical difference in the survival rate of the 10-mm implants when compared to the shorter series (P > .05) or between the various implant diameters. The mean marginal bone loss was 0.71 +/- 0.65 mm. Discussion The failure rate of 4.5% compares favorably with that of implants of different shape, surface characteristics, and length. Bone quality appeared to be the critical factor in implant survival, rather than bone quantity, in this patient series. Conclusions This study supports the survival of short, machined-surface implants when used for the treatment of partial edentulism in bone of good quality.

A targeted review of study outcomes with short (< or = 7 mm) endosseous dental implants placed in partially edentulous patients.

Generally, threaded root-form endosseous dental implants are thought to perform poorly in short lengths (i.e., < 10 mm). However, whether modifications in implant surface geometry will improve performance of short threaded implants is less clear. The relationship between dental implant failure rates and their surface geometry, length, and location (maxilla versus mandible) was explored in the published literature. Using a MEDLINE search (1985 through 2001), studies were sought with the following criteria: 1) data suitable to calculate failure rates of implant lengths < or = 7 mm versus > 7 mm; 2) data separable into maxillary versus mandibular results; 3) criteria for "failure" clearly defined; and 4) minimal functional period of 2 years. Twelve papers were identified as follows: eight with machined threaded implants, two with acid-treated threaded implants, and two with sintered porous-surfaced press-fit implants. The following results were found: 1) machined surface implants experienced greater failure rates than textured surface implants; 2) with the exception of sintered porous-surfaced implants, 7 mm long dental implants appear to have higher failure rates than those > 7 mm length; and 3) with textured surface implants, higher failure rates were more likely in the maxilla than in the mandible, but with machined surface implants there were no differences in failure rates between maxilla and mandible. Dental implant surface geometry is a major determinant in how well these implants perform in short lengths, defined here as lengths of < or = 7 mm. While threaded implants show higher failure rates in short versus longer lengths, sintered porous-surfaced implants perform well in the defined "short" lengths. More studies are needed to better assess the performance of short, acid-washed threaded implants.

Five‐Year Survival Distributions of Short‐Length (10 mm or less) Machined‐Surfaced and Osseotite® Implants

In cases of reduced alveolar bone height, implants of short length (10 mm or less) may be employed although there is a perceived risk that because of their small stature they will be unable to tolerate occlusal loads and will fail to osseointegrate. This report describes an analysis of prospective multicenter clinical studies evaluating the risk for failure of short-length implants, comparing dual acid-etched (DAE) Osseotite implants (Implant Innovations, Inc., Palm Beach Gardens, FL, USA) to machined-surfaced implants. Admission criteria were the same for both data sets. Baseline variables of demographics including age, gender and smoking status, bone quality, location, implant dimensions, and types of prostheses were compared to ensure balance among groups. Cumulative survival rates (CSRs) were calculated with the Kaplan-Meier estimator. The implant data included 2294 implants for the DAE series and 2597 implants for the machined-surfaced series. Patient demographics showed similar percentages of occurrence for all variables. The distributions of implants between short- and standard-length data sets for baseline variables including width, location, and restorative type were similar, qualifying these data sets for comparison of the independent variable of length. Overall, there was a 2.2% difference in 5-year CSRs between the machined-surfaced short- and the standard-length implants. For these implants a 7.1% difference was observed in the posterior maxilla and an 8.5% difference in the anterior maxilla. For DAE implants the overall difference between "standards" and "shorts" was 0.7%, which is not statistically significant. In this analysis the difference in CSRs between short- and standard-length implants was greater for machined-surfaced implants than for DAE implants.

The removal torque of titanium screw inserted in rabbit tibia treated by dual acid etching

Chemical acid etching alone of the titanium implant surface have the potential to greatly enhance osseointegration without adding particulate matter (e.g. TPS or hydroxyapatite) or embedding surface contaminants (e.g. grit particles). The aims of the present study were to evaluate any differences between the machined and dual acid etching implants with the removal torque as well as topographic analysis. A total of 40 custom-made, screw-shaped, commercially pure titanium implants with length of 5 mm and an outer diameter of 3.75 mm were divided into 4 groups, 10 screws in each, and chemical modification of the titanium implant surfaces were achieved using HF and HCl/H 2SO 4 dual acid etching. The first exposure was to hydrofluoric acid and the second was to a combination of hydrochloric acid and sulfuric acid. The tibia metaphysics was exposed by incisions through the skin, fascia, and periosteum. One implant of each group was inserted in every rabbit, 2 in each proximal tibia metaphysics. Every rabbit received 3 implants with acid etched surfaces and 1 implant with a machined surface. Twelve weeks post-surgically, 7 rabbits were sacrificed, Subsequently, the leg was stabilized and the implant was removed under reverse torque rotation with a digital torque gauge (Mark-10 Corporation, USA) (Fig. 1). Twelve weeks after implant placement, the removal torque mean values were the dual acid etched implants (24%HF+HCl/H 2SO 4, group C) required a higher average force (34.7 Ncm), than the machined surface implants (group A) ( p=0.045) (Mann-Whiteney test). Scanning electron micrographs of acid etching of the titanium surface created an even distribution of very small (1–2 μm) peaks and valleys, while machining of the titanium surface created typical microscopically grooved surface characteristics. Nonetheless, there was no difference in surface topography between each acid etched implant groups. Therefore, chemically acid etching implant surfaces have higher strengths of osseointegration than machined implant surfaces. There is less correlation between removal torque and the difference in HF volume%.

Bone-to-Implant Contact according to the Surface Roughness of the Implants

【This study was performed to evaluate the difference of the bone-to-implant contact according to the surface roughness of the implants. Two beagles were used in the experiment. Extraction of the all premolars was performed in the mandible. In 3 months of healing, screw-shaped pure titanium machined surface implants (Implantium(R), Dentium Co. Korea), implants blasted with 45 ${\mu}m$ $TiO_2$ particles, (Implantium(R), Dentium Co. Korea) and implants blasted with 100 ${\mu}m$ $TiO_2$ particles (Implantium(R), Dentium Co. Korea) in diameter 3.4mm and length 6mm were installed in the edentulous mandible. Each dog was sacrificed at 4, 12 weeks after placement and then nondecalcified specimens were prepared for histologic analysis. The results of this study were as follows. 1. At 4 , 12 weeks after the surgery, bone-to-implant contact in the surface blasted with $TiO_2$ particles was higher than that in the pure titanium machined surface respectively. 2. Osseointegration in the surface blasted with 45 ${\mu}m$ $TiO_2$ particles was more increased than that in the surface blasted with 100 ${\mu}m$ $TiO_2$ particles. 3. Bone-to-implant contact was increased with time independent of surface roughness. 4. Bone formation was in the outfolded area more than inside the threads independent of surface roughness. From the above results, we were able t o find the most bone-to-implant contact in 45 ${\mu}m$ $TiO_2$ blasted implant.】