WHAT IS RBM?
RBM, or resorbable blast media, has been utilized for over 15 years in the dental implant industry.

This surface treatment is designed to roughen the implant surface without leaving the residual embedded blast particles or debris in the treated substrate. To achieve the desired roughening the implant is blasted with suitable hardened particles of Hydroxyapetite (beta-Tricalcium Phosphate, Alpha Tcp, TTcp and Calcium Phosphate (CPP) and then subsequently dissolved from the surface with a defined passivation treatment. Surface roughness between Ra 1.2 - 1.5 is consistently achieved.

The result is a rougher implant surface then traditional acid etch treatment providing a greater surface area for osseointegration, improved retention characteristics, increased biological fixation, and maximizing implant-to-bone contact.

RBM SURFACE STUDIES
A PROSPECTIVE, MULTICENTER, 4-YEAR STUDY OF THE ACE SURGICAL RESORBABLE BLAST MEDIA IMPLANT.
J Oral Implantol 2003; 29(4):174-80 (ISSN: 0160-6972)
Gonshor A; Goveia G; Sotirakis E
McGill University, Oral and Maxillofacial Surgery, Montreal, Quebec, Canada.
arongonshor@hotmail.com

This article reports on the 50-month results of the evaluation of the ACE Surgical resorbable blast media (RBM) dental implant. There were 1077 implants placed in 348 patients: 950 in the mandible and 127 in the maxilla. A total of 78.6% of the implants were used to support anterior, mandibular, bar-retained overdentures. The 3.75- to 4.00-mm-diameter implant was used in 91.1% of cases, with the remainder being 3.3 mm (2.2%) or 4.75 mm (6.7%). The implants of 10-, 13-, and 15-mm lengths were used in almost equal amounts in the mandible, maxilla, and anterior or posterior aspects of either jaw. There were 7 failures, all in the mandible and before stage 2 surgery. The overall implant success rate in this 50-month interim report is 99.3% in the mandible and 100% for the maxilla. There was no discernible crestal bone loss during the study period. No differences in bone response were seen in RBM implants with roughened surfaces on the entire implant, up to the collar, or up to the first 2 threads below the collar.

BONE RESPONSE TO MACHINED AND RESORBABLE BLAST MATERIAL TITANIUM IMPLANTS: AN EXPERIMENTAL STUDY IN RABBITS.
J Oral Implantol 2002; 28(1):2-8 (ISSN: 0160-6972)
Piattelli M; Scarano A; Paolantonio M; Iezzi G; Petrone G; Piattelli A
Dental School, University of Chieti, Chieti, Italy.The clinical success of dental implants is dependent on successful osseointegration. An important parameter for achieving osseointegration is the establishment of direct contact between the surface of the implant and the surrounding bone. There have been numerous studies indicating that implant surface roughness affects the rate of osseointegration.1,2

A variety of endosseous dental implants with unique topographies are commercially available. Dental implant manufacturers have modified implant surfaces through mechanical, chemical, electrochemical and laser treatments in their efforts to create implants that promote accelerated healing and osseointegration (Fig. 1). For example, the resorbable blast media (RBM) surface treatment technique utilizes calcium phosphate, a biocompatible material, to increase the surface area of implants and provide greater bone-to-implant contact. RBM-treated materials are also osteoconductive and thus encourage the growth of cells. RBM treatment creates an extremely clean implant surface that does not inhibit the gathering of osteoblast precursor cells. Furthermore, the hydrophilic surface of RBM-treated implants draws the blood, and the cells carried in the blood, to the surface quickly. This is advantageous and supports successful implant therapy because the cells initiate bone development on the implant.3,4

im0502-implant-surface-treatment-01
Figure 1: Overview of implants and their respective surface treatments.5,6

In this literature review, a number of long-term prospective and retrospective studies were critically assessed in order to evaluate the clinical performance of a variety of dental implants, along with their respective surface treatments. The studies utilized for review reported and analyzed success and survival rates, and were published within the past 11 years.

Prospective Clinical Studies
A nine-year longitudinal study included 2,132 implants placed in 731 patients. In this study, 1,374 MTX screw-type implants and 758 HA-coated implants were placed. At the end of nine years, the authors reported a cumulative survival rate of 97.9%.7

Another study included 386 HA-coated implants and 234 RBM external hex implants over a period of six years. The survival rate for the implants was 96.6% and 95%, respectively.8

im0502-implant-surface-treatment-02
Figures 2a, 2b: The RBM surface featured on many implants, including the InclusiveŽ Tapered Implant (Glidewell Direct; Irvine, Calif.), was first introduced in the early 1990s. Since then, the RBM surface has become one of the most widely used dental implant surface technologies in the world. The RBM surface is a well-documented, proven surface that leads to high success in all bone types.

The aim of the present study was a comparison of implants' responses to a machined surface and to a surface sandblasted with hydroxyapatite (HA) particles (resorbable blast material [RBM]). Threaded machined and RBM, grade 3, commercially pure, titanium, screw-shaped inplants were used in this study. Twenty-four New Zealand white mature male rabbits were used. The inplants were inserted into the articular femoral knee joint according to a previously described technique. Each rabbit received 2 inplants, 1 test (RBM) and 1 control (machined). A total of 48 implants (24 control and 24 test) were inserted. The rabbits were anesthetized with intramuscular injections of fluanisone (0.7 mg/ kg body weight) and diazepam (1.5 mg/kg b.wt.), and local anesthesia was given using 1 mL of 2% lidocaine/adrenalin solution. Two rabbits died in the postoperative course. Four animals were euthanatized with an overdose of intravenous pentobarbital after 1, 2, 3, and 4 weeks; 6 rabbits were euthanatized after 8 weeks. A total of 44 implants were retrieved. The specimens were processed with the Precise 1 Automated System to obtain thin ground sections. A total of 3 slides were obtained for each implant. The slides were stained with acid and basic fuchsin and toluidine blue. The slides were observed in normal transmitted light under a Leitz Laborlux microscope, and histomorphometric analysis was performed. With the machined implants, it was possible to observe the presence of bone trabeculae near the implant surface at low magnification. At higher magnification many actively secreting alkaline phosphatasepositive (ALP+) osteoblasts were observed. In many areas, a not yet mineralized matrix was present. After 4 to 8 weeks, mature bone appeared in direct contact with the implant surface, but in many areas a not yet mineralized osteoid matrix was interposed between the mineralized bone and implant surface. In the RBM implants, many ALP+ osteoblasts were present and in direct contact with the implant surface. In other areas of the implant perimeter it was possible to observe the formation of an osteoid matrix directly on the implant surface. Mature bone with few marrow spaces was present after 4 to 8 weeks. Beginning in the third week, a statistically significant difference (P < .001) was found in the bone-implant contact percentages in machined and RBM implants. It must be stressed that these results have been obtained in a passive, nonloaded situation.