V.A. Study Three-Year Results
Hydroxyapatite-Coated Implants: A Case for Their Use

TRADEMARKS: Core-Vent, SwissPlus, Screw-Vent, Advent, Bio-Vent, Micro-Vent, Friction-Fit, Dual Transition Selective Surface are now Implant Trademarks of Zimmer Dental Implant Company 1900 Aston Avenue, Carlsbad, CA 92008

 
VA Study Three-Year Results:
    
1: Prologue and Data Analysis
2: Introduction
3: Hydroxyapatite vs. Titanium Implants
4: DICRG Study Design
5: Goals of the Paper
6: Results and Discussion
7: References

 

Section 1: Prologue and Data Analysis

     Too often, clinical studies have been conducted and analyzed under the direction and control of implant manufacturers. The validity of such results is, at best, biased by selecting only those clinicians with extensive experience with the implant system in question, or by excluding results from centers that report lower success rates.

     Without independent controls and peer review mechanisms, there is no assurance that the results even represent consecutively inserted implants. When the lead authors of such studies are owners, employees and/or paid consultants of the company whose products are being evaluated, any claims related to success rates must be conSIDered highly questionable. By the same token, criticism of other implant systems by such corporation-linked spokespersons should be viewed with the same degree of skepticism.

     The following three-year report on the results of 2,795 implants manufactured by Core-Vent Bio-Engineering provides the dental profession with an unbiased standard for clinical research. This prospective, multi-center study by the U.S. government's Veterans Administration is conducted under the strict controls of an external peer review committee. This distinguished panel of researchers and educators has been assembled to assure the validity of the data and the objectivity of the analysis. By placing different implants within the jaw of the same patient, this study provides a better understanding of the synergy between implant design, material and surgical protocol. The VA study is providing information to serve as a scientific basis for reaching clinical treatment and product design decisions. These results are representative of real-world situations for two important reasons. First, this study includes the results of implants placed by surgeons of various skill and experience levels. Second, this study has not excluded smokers or medically compromised patients. Furthermore, the use of preoperative antibiotics for approximately half of the patients in the study resulted in higher implant survival rates for those patients, while withholding such prophylactic therapy from others reduced the overall success rate, as documented in this paper. Although this unabridged article only reports on the three-year results, the VA study is ongoing. The authors state in the summary that "2,000 implants with four-year data and 1,500 with five-year data" have been documented. They further state that "these data are similar to the 36-month data and, when they are eventually released, are likely to reinforce the results reported here."

     The following analysis of the results reported in this 3-year report clearly demonstrate that -at least in the 3- to 5-year initial period- HA-coating on an implant neutralizes differences in achievement and maintenance of osseointegration with different qualities of bone and experience levels of surgeons. Similarly, smokers and those patients denied preoperative antibiotic therapy also experienced significantly fewer failures with HA-coated implants than uncoated implants. This report also demonstrates that results with uncoated, acid-etched implants more closely parallel results with HA-coated implants when inserted by more-experienced clinicians in dense bone, regardless of material (CP Ti vs. Ti alloy) or design (cylinder, basket, screw).

Editorial Excerpt: The Search for a More Successful Implant

    Properly designed, randomized, clinical trials are expensive, time and labor intensive, and require an adequate patient population to provide reliable data. As a result, too few of such studies are done and we find ourselves extrapolating information information from case reports, small clinical series, and inadequately controlled retrospective studies. The US Veterans Administration's multi-center, prospective implant study represents a unique opportunity to provide unbiased answers to many of the questions that still trouble clinicians. Through the vision and commitment of one manufacturer a group of outstanding clinicians were given the autonomy to design the research protocol, conduct the study, and publish the results independent of any commercial influence...Congratulations are extended to all those who made this study possible: Dr. Gerald A. Niznick for his generous support, Dr. Harold Morris for his leadership, the more than 100 clinicians for giving so enthusiastically of their time and skill, and the members of the Scientific Advisory and External Review Committees who assured the validity and objectivity of the results.

Daniel M. Laskin, Editor-in-Chief
J Oral Maxillofac Surg 1997;55(11) Suppl 5:1.