Long Term Survival Results of Bicon Implants Including Bicon’s 6.0 x 5.7mm Implant

Thank you Dr. Pullen. Thank you Dr. Pullen for the nice introduction. And thank you Dr. Morgan and Bicon Dental Implants for the honor to present a presentation on my clinical studies for Bicon dental implants. I have two short talks. The first talk is on immediate loaded implants, and its survival estimates and risk factors for failure. For more than twenty years, the traditional implant protocol included a three to six month load free healing period before initiation of the second stage or restorative procedures. Conceptually, it is believed that osseointegration must occur before the implant is loaded to minimize the risk of failure. Needless to say, this approach necessitates a prolonged course of treatment. Patient desires a shorter implant treatment course without sacrificing implant success. Recently, the delayed loading concept has been challenged by a new protocol, in which implants are being loaded about zero to seventy two hours after placement. Immediate loading on implants not only shortens the treatment time, but it gives patients an acceptable aesthetic experience during the treatment period. The concept of unloaded healing has been challenged, and immediate loading has become popular. Immediate loading implants, as I emphasize, is shortened treatment, immediate restoration and functions. However, there might be a possibility of increase for implant failure. In terms of immediate loading, as I indicated, there’s wide variation of definitions among immediate loading definitions. The full occlusal load placed on the implant to a fixed or removable prosthesis, provisional or permanent, usually within forty eight to seventy two hours after placement. In our study, functional, fixed, provisional prosthesis placed on an implant on the same day as implant placement. The purpose of this study was to estimate implant survival, and identify factors associated with implant failure in subjects receiving immediate loaded implants. Our hypothesis was that there exist risk factors that can assist and can be modified by the clinician to decrease the probability of implant failure. Our specific aims are, the first specific aim was to estimate the one year survival rate of the immediate loaded implants. The second specific aim was to identify risk factors associated with implant failure of immediate loaded implants. Our study design is a retrospective cohort study design, and all patients who had at least one Bicon implant placed and immediately loaded between the duration of September two thousand and one and July two thousand and three at the implant dentistry center located at Jamaica Plain, Massachusetts was eligible for inclusion in the study. The occlusal load was again applied at the same time of implant insertion, meaning within the twenty four hours’ time, our exclusion criteria was any patients who did not have an implant placed or have missing data. Our study variables and or predictor variables was grouped in the set of nineteen different variables reported to be associated with implant failure. These variables were grouped into the following set of exposures or predictive variables. First is demographic, health status, anatomic, implant fixture specific, prosthetic, and surgical variables. Our primary outcome variable was the clinical status of the implant at the end of the follow-up, classified as failed or survived. Implant failure, which was defined as the removal of the implant, or explantation. The duration of implant survival was determined by calculating the time, in months, between the implant placement and the date of the last follow-up visit, or implant removal. In terms of data analysis, we computed all the descriptive statistics for all of the study variables. The one year survival of the implants was estimated using the Kaplan Meier survival method. This is a nonparametric survival estimation. It doesn’t rely on any distribution assumptions. The univariate Cox proportionate hazards analysis were used to identify variables associated with implant failure. The multivariate Cox regression model was then built using the biologic and statistically or near statistically significant variables associated with implant failure. Here is a brief setup of how the data analysis is constructed, but since the majority of audience here are not statisticians or biomechanic engineers, this is briefly to illustrate is that the this is the old days where the hazard or the risk of having an implant failure given the covariate information, for example, patient’s age, gender, anatomic such as maxilla, mandible, implant size, abutment size, these are also called covariate information. At time point t, the risk of having a problem at time point t is a baseline hazard of the implant. And this is exponential with the parameters and the covariate factor, which collect all the information of this particular patient. But because of the clustering of implants within the same subject, meaning that multiple implants can be placed on the same patient, we denote a indicator, the kth implant of the ith patient at time point t, the risk of having a problem at time point t equals the baseline. Lambda zero here is a baseline risk and exponentiate with the beta functions and the covariant vector z, which contains all the information on the patient level information and sub implant level information of the kth implant of the ith patient. And thank to doctor Morgan who give us the unfettered access to data records. This part of the formulation ultimately become a current funded NIH r o three grant, which is funded by the National Institute of Health of the United States. So I thank you doctor Morgan for that. In terms of the descriptive statistics, our sample included two hundred and nine patients and four hundred and seventy seven immediate loaded implants. The mean age of the patients was fifty four years old, and the standard deviation is about fifteen point eight years old. As you can see, about close to fifty percent of the patients are male patients, and usage of tobacco comprises about ten percent for the smokers. In terms of the anatomic variables, in this particular cohort study, almost seventy six percent was placed in the maxilla, and about fifty three percent was placed in the anterior location by means of canine to canine position. In terms of the anatomic variables, the amount of fixed load applied to the immediate loading protocol is about eighty five point three percent. And in terms of bone quality, as you can see, the dominant group is about almost fifty percent was placed in type four quality bone. We also attempt to collect many other anatomic variables, including about forty one percent of the implants was placed in sites that previously had a root canal treated tooth, and approximately twenty four percent of the implants was placed in sites that were adjacent to one or root or two root canal treated tooth. Because what we think about is that any prior history of peri infections, peri implant infections, or peri tooth infections may result in the shortened survival of the implant placed. And also fifteen percent of the implants were placed at sites that had the radiolucency at or adjacent to the implant site. In terms of the implant fixture specific variables, as you can see, the dominant group is about the four point five millimeter implant, which compares almost forty percent of the study cohort, and the implant length, as you can see, is about eight millimeter implant, which comprises close to seventy percent of the study cohort. In terms of the well size, again, the dominant group is about eighty point one percent was placed with three millimeter well. In terms of the implant coating surface, predominant group is ninety eight point five percent has some version of coating, either a TPS type or type coating. The other one point five percent is uncoated implants. We also attempt to collect some prosthetic variables. This include the total number of units in the temporary prosthesis spent, which is the sum of the implants, the natural teeth, and the pontics. And you can see that about thirty percent had three total number of units in the temporary prosthesis, and about twenty six point eight percent had seven to fourteen as the total number of units in the temporary prosthesis span. In terms of other prosthetic variables, we also collect the total number of pontic units participate in the temporary prosthesis, and you can see that majority eighty two point one percent was have note, temporary pontic units. In terms of the reconstruction at the recipient site, nine percent of the implants was placed in reconstructed recipient sites. Reconstruction techniques used in this sample included multiple augmentation procedures, included the sinus lift, possible usage of barrier membranes, autogenous or allogenetic bone grafts, comprises the nine percent of the study cohort. And about fifty percent of the implants was placed at the same time as the tooth was being extracted as a fresh extracted wound, and the other fifty percent was placed after extraction site has healed. The overall one year survival estimate was approximately ninety point three percent, and the confidence interval ran for about eighty seven percent to ninety four percent. This resulted in a sample size of two hundred and nine patients, four hundred and seventy seven implants, and twenty three failed implants. Of the nineteen risk factors we look at, three of them were statistically associated with implant failure. This was the presence of coating, which without presence of coating, you have close to seven times more likely to fail. If you increase the number of pontic units, you are twice as much likely to fail. And also, the condition of the implant site. If you have a delayed implant protocol, you are two point five times more likely to fail based on the delayed loading I mean, delayed implant placement protocol. We include these three candidate variables plus age and gender into the multi variant *** proportional hazards model analysis. And what you can found that after adjusting for age and gender in the multivariate model, implant coating becomes twenty two fold more likely to fail if it is an uncoated implant. And I believe that this is probably just a overinflation because keep in mind, our study comprises about ninety eight percent of some variation of coating and two percent has known non coating implants. So because of the small sample, very small sample size in the uncoded group, the standard error sometimes or standard deviation of calculation could become problematic. But the computer attempted to correct it and it results in a hazard ratio or relative risk of twenty two times. But I believe that if you have larger sample size, the hazard ratio estimate or risk factor estimate may go down. The total number of pontic units, you can you can see that, is about twice as likely to fail if you have increased the pontic units. The condition of implants that you have a delayed implant site protocol, you are about close to fourfold that you’re more likely to fail with immediate loading implant setting. Again, to review, the purpose of this study was to estimate the implant survival and identify factors associated with implant failure in subjects receiving immediately loaded implants. We hypothesized there are risk factors that can exist, which can be modified by the clinician to decrease the probability of implant failure. Our specific aims was to estimate the one year survival rate of immediate loaded implants, and to identify the risk factors associated with failure of immediate loaded implants. The overall survival of immediate loaded implant system is about ninety point three percent with confidence range from eighty seven to ninety four. While this may be an acceptable level of implant survival, I believe that most of the audience would agree that the one year survival estimate of immediate loaded implants may be at the lower end of the range of the implant survival reported in the literature, which is conducted in a loaded in a delayed manner. But keep in mind, studies can be flawed because that usually without proper adjustment of follow-up time, the survival rate always looks better. They can easily look fifteen percent higher. So when you look at literature that supports survival rates, you have to carefully and scrutinize the proper adjustment of follow-up time and the clustered correlation issue about implants that are placed within the same patient. And so when a marketing person advertise you how good their studies are, put it keep in mind, it’s the follow-up time adjusted because implant failed at one month is not the same as implant failed at one year. And this is commonly done in implant research to overinflate the reporting of implant survival. So I just want to make the point to you. While there may be some other tangible benefits to selecting immediate loaded implants, primarily directed at enhancing patient convenience, there may be an associated price to pay in terms of a decreased rate of implant survival. After controlling for multivariate regression analysis, we note that coating, which has no coating surface, increasing the number of pontic units, and delayed condition of the implant site was associated with implant failure. Now our studies, of course, has study limitations like any typical study. Again, this is the retrospective cohort study design, which is usually not the best strong evidence. It’s so called the level two evidence based medicine or dentistry. It is one center for implant placement. They also potentially have missing charts, or incomplete information. Also, there are also different time points at which the subjects are returned for follow-up. And at the time when this study concluded, there is no long term follow-up. I would like to acknowledge my colleagues and coworkers and also the Bicon Implant Dentistry Center for the unfeltered access to patient records. Thank you. And my next presentation is on short implants, survival estimates, the six by five point seven, actually, and the survival estimates and risk factors for failure. As Shadi Daher has mentioned to you that short implants offered a practical option for prosthetic restoration in the face of anatomic limitations, including situations in which there is a loss of alveolar bone height, the proximity of maxillary sinus, and also the proximity of the inferior alveolar nerve canal. Again, in the literature, if you look at it, implants of less than ten millimeters can still remain controversial. Most of the literature points out that higher failure rates, up to twenty one point five percent has been reported in the literature. However, recent studies, which I can mention a few, show that survival estimates are comparable to that of longer implants in the range of ninety four to ninety eight point four percent. The increasing implant diameter has suggested a way to tolerate occlusal forces to improve stability and to provide a favorable stress distribution. And success rate, again, based on the literature, is about two point three percent to twenty nine percent. However, there’s very few studies combining short implant length with wide diameter. And the purpose of this study is to report the clinical outcomes of the Bicon six by five point seven millimeter implants. For the purpose of this presentation, this paper or this research has been accepted for publication in the International Journal of Oral and Maxillofacial Implants, August two thousand and five. I got the official note, but I’m still waiting for the final print to appear in the IJOMI literature. Our hypothesis is that the combination of a short implant length with a wide diameter is a clinical acceptable option when indicated, resulting in survival rates similar to that of longer implants. Our specific aims of the study is to look at the survival of the six by five point seven millimeter implant to compare the survival of the six by five point seven millimeter implant with the non six by five point seven millimeter. Keep in mind, when we conduct the comparison, we’re conducting implants placed within the same patient. So all the external factors of age, gender, and other variables are controlled within the same patient. So these two sets of implants are within the same patient, and also to identify risk factors associated with implant failure. In terms of our study design, a retrospective cohort study design was conducted, and the sample, as Shadi mentioned, there’s at least one six by five point seven placed at the IDC from about January of twenty seven nineteen ninety seven to about June eight two thousand and two when this study, premiere analysis of this study completed. And again, our exclusion criteria were that there’s no inpatients who had a six by five point seven millimeter implant or whose chart are unavailable. Again, our predictive variable is the implant size. So obviously, the six by five point seven seven six by five point seven millimeter implant is the main comparison or the main group. And our non six by five point seven millimeter implant could have a range of various length of eight to fourteen or diameter from three to six. But we we sort of grouped them as non six by five point seven, again, trying to compare those within the same patient. Again, our primary outcome variable is implant failure, again, defined as explantation or removal of the implant, and the survival of each implant was computed from the time of implant placement to the patient’s last follow-up visit or implant removal. Our study variables were grouped again into the following categories. The demographic included the age of implant placement and gender. The health status variable included the patient’s ASA status, which is the American Society of Anesthesiologists, and the presence of a medically compromising conditions such as radiation, chemotherapy, and immunosuppressive therapy, and the usage of tobacco. Our anatomic variables included the proximity of the implant location and the proximity of the implant, the bone quality, one to four, the implant specific variables included the length, the diameter, the coating, the well size, staging of the implant, and immediate implant placement after a tooth extraction, and various prosthetics such as fixed and removal type prosthesis. Our perioperative variables included the usage of antibiotics, and the reconstructive variables included again the various type of reconstructive such as sinus lift, various membranes, bone graft, possible ridge split procedures, and different grafting type materials. Again, our data analysis comprises of univariate and multivariate statistics was computed. The Kaplan Meier survival analysis was used to determine the one year survival rates at the associated ninety five percent confidence intervals. And the Cox Proportional Hazards model were used to identify exposures associated with implant failure and a multivariate Cox Proportional Hazards model was then created and analyzed. You can look at this particular table with a sample size of thirty five patients and one hundred and seventy two implants placed within the thirty five patients. And you can see that forty five patients, implants was placed by the six by five point seven group, and hundred and twenty seven implants was the non six by five point seven. In terms of the age distribution, they they looks a little older, but there’s not statistically significant. The gender, in terms of the male gender distribution, not particularly statistically significant. The a a ASA status may look on the borderline sin significance, and presence of a medical compromised condition is at the borderline statistical significance. In terms of the position, the jaw positioned maxilla has a point o eight, close to statistical significance. The presence of the posterior maxilla, close to statistical significance. Staging one stage procedure, close to statistical significance, and usage of reconstruction procedures at the borderline of statistical significance. In terms of the Kaplan Meier estimates of the Bicon systems, the six by five point seven versus the non six by five point seven, you can look at at the one year, the six by five point seven is about ninety two point two, whereas the non six by five point seven comparing within the same patient ninety five point two percent. But however, it means that there’s no big difference in terms of statistical difference between the two two groups. Now I just wanna show you this quick historical table where this paper was published in Journal of Dental Research in two thousand and one, where vigorous survival analysis was conducted. And you can see that the one year survival of ninety five point four. So you can look that these studies are very comparable to each other. In terms of the univariate analysis for risk factors associated with implant failure, again, with thirty five patients and hundred and seventy two implants, these are the candidate variables that may be associated with failure on the one by one. Univariate means at a single one sense. And we can find that the issue of medical compromise and the issue about staging may affect the survival in the multivariate regression modeling. Again, using the candidate variables, we found that the staging is only one of the significant variables that pop out in the multivariate regression analysis. But again, I wish that we have larger sample size. Keep in mind, this is again thirty five patients and only hundred and seventy two implants when the preliminary analysis were concluded in two thousand and two. Again, our aims of this study was to look at the survival of the Bicon six by five point seven millimeter implants and to look at the survival of the six by five point seven comparing to the non six by five point seven within the same patient, and attempting to look at potential risk factors associated with implant failure. Our discussion resulted in a ninety two point two percent for the six by five point seven, and the non six by five point seven is ninety five point two percent. And this have very similar survival estimates of other implant system. Our historical data, as I said, part of this results was published in j JDR, Journal of Dental Research two thousand and one, and subsequent a a lot of few other papers are subsequently published. It’s not significantly varying even with a larger sample size of six hundred and sixty patients and two thousand two hundred and eighty six implants. Again, the results are pretty consistent, irregardless of what time of cohort we look at the study patients. It is important to know that there might be some important differences between this study and most of the published data. The first definition is the definition of short. Most studies, if you look at the literature, still define short implants as being less than ten millimeters in length. In fact, as Shadi has also mentioned, majority of implants are usually seven millimeters in length. However, our implant short implant here was reported is six millimeter in length. And the other important difference is that there are very, very few studies that combined a short implant length and a large diameter. To me, this is one of the very first study, and I believe that I want I don’t wanna say we are the first group, but it’s one of the very first in this country that had a acceptable publication reporting the clinical outcomes of the six by five point seven millimeter implant system. Of course, like every study, there are also limitations to the study. Again, our sample size of forty five patients and hundred and seventy two implants, I still consider them small. And when the time is conduct when the study time is conducted, there has very good follow-up data beyond one year. But we we I believe when we look we look at the data again, We can reanalyze the data and report very similar favorable results. The conclusion sites reported that the survival of the six by five point seven millimeter implants is comparable to the non six by five point seven millimeter implants. And we believe that, again, this is this implant size and diameter and length is a a clinical acceptable option for the prosthetic reconstruction in face of other multi factors. Finally, I would like to, again, thank you for my collaborators, and of course, we have to thank all the clinicians and supporting staff of the Faulkner Hospital Implant Dentistry Center for their cooperation and unrestricted access to patient records. I thank you so much for your time and attention. Thank you.