A retrospective analysis of bone and its relationship to implant success and patients' age

Date
2004
DOI
Authors
Pourati, Jacob A.
Version
OA Version
Citation
Abstract
Implants have been overwhelmingly successful. After the first series of implant follow-up studies in the early 1980's, a trend was noticed with implant failure that was directly related to the bone density of future implant site (FIS). For this reason Lekholm and Zarb (L&Z) as well as their colleagues created new bone quality classifications to accommodate the implant treatment plan. After the introduction of the CT-scan, advances in bone augmentation techniques, implant surface modifications, a better understanding of implant force distribution and the effect of age on bone density, the relationship between bone quality and implant retention has become a more controversial topic. This research study will attempt to answer some of those preliminary questions about bone density and its effect on implant retention using a retrospective chart and CT-scan analysis of patients treated with implants using multiple methods to determine bone quality. The following topics are reviewed in this study. (1) Evaluate bone quality of FIS using Lekholm and Zarb technique and Quantitative CT (QCT) and its affect on implant retention. (2) Relation between 3 age groups' (17-50, 51-65, 65-85) bone quality and implant success. (3) Systemic influence, such as diabetes and smoking habits, on implant retention. MATERIAL AND METHODS: In this retrospective IRB reviewed and accepted research study, 73 implant patients of Boston University Goldman School of Dental Medicine (BUGSDM) Center of lmplantology from the time period 1999-2002 with available references were evaluated. The preoperative CT-scan of FIS of these patients with undisturbed bone (virgin bone) were evaluated for average cortical thickness, cancellous density measured in Houndsfield Units (HU), cancellous volume percent, quality of the bone inside the projected implant site or inside of the implant (HU), quality of the bone surrounding 1mm of the projected implant site (HU) or outside of the implant and also evaluated using the Lekholm and Zarb classification. Other implant sites that were done with bone modifying procedures were also documented to achieve a statistically larger population to evaluate the affects of age, smoking and diabetes on long-term implant retention. Patients received either 3i (West Palm Beach, Florida) or Zimmer implant system and were allowed a 4-6 months healing period before loading. Patient's charts were followed up to 24 months. RESULTS: Seventy-three patients (31.5 % of the total patients evaluated) were eligible to be used for the bone analysis portion of this research. This allowed 137 implants in our bone analysis study with 6 reported failures, all reported as early failures. Due to the fact that this is a retrospective chart review, the follow up period varied among the implants from the time of loading to more than 24 months. The original population of 73 patients with 137 implants was evaluated for Lekholm and Zarb bone classification, QCT bone variables described in this study and their affects on implant retention. The results indicated that the Lekholm and Zarb classification (Dl-D4) (analyzed by one calibrated study personnel) correlated with statistical significant with the QCT variables analyzed, and neither of these bone quality classifications and variables had correlation with the age of the patient or their respective implant retention. No statistical significant correlation was seen between the evaluated bone variables and implant outcome. Total patient population of 232 (538 implants with 20 reported failures), which included the original 73 patients and additional 159 patients who did not have a virgin bone site to allow them to qualify for the bone analysis, was divided into 3 age groups to evaluate the effects of age on implant retention. Group one (18-50) had 115 patients, group two (51-65) had 86 and group three (65-85) had 31 patients. With the whole population, the success rate of the implants was 93.7 percent. There was no statistical significance between patient age groups and implant success. Among the values evaluated in the patients, reported smoking habit (p value 0.03) and diabetes (p value 0.063) both had a significant impact on implant failure rate. Patients who are reported as smokers on their health questioner, had a 4.7 times increase in failure rate than reported non-smokers. Reported diabetic patients had similar failure odds ratio of 6.
Description
Thesis (M.S.D.)--Boston University, Goldman School of Graduate Dentistry, 2004 (Oral Biology and Periodontology).
Includes bibliographical references (leaves 78-88).
License
This work is being made available in OpenBU by permission of its author, and is available for research purposes only. All rights are reserved to the author.