Retrospective analysis of records for 2048 patients who received dental implants between January 1, 2011, and December 31, 2015, at Louisiana State University Health Science Center (LSUHSC) School of Dentistry was completed. This study was approved by the LSUHSC Institutional Review Board (IRB#9397).
Patients between 18 and 80 years of age whose records indicated that they received dental implants between January 1, 2011, and December 31, 2015.
The exclusion criteria are the following:
Patients whose implants presented with mobility at the time of placement and were removed
Patients with incomplete records
Patients with no follow up for at least 1 year or more after implant placement
Determination of implant survival
Implant survival was defined as the presence of the implant at the time of evaluation of records. The data collected from the patient records included demographics (age and gender), implant site characteristics (site, graft, sinus elevation, implant system, length, and diameter), and two known confounding factors (smoking and diabetes). The study variables were the specialty, year of resident training, and implant system. Based on the inclusion and exclusion criteria, a total of 1449 implants were included in the study. Survival or failure of an implant was based on the presence or absence of the implant at 1 year after placement. The data on implant survival or failure was categorized by the specific department of the resident who placed the implant (Periodontics, OMFS, or Prosthodontics) and by the year of residency training.
Data analysis was completed using the Statistical and Machine Learning toolbox in MATLAB R2017a™ (Mathworks Inc., Natick, MA) and SAS version 9.4 (SAS Institute Inc., Cary, NC) Implant outcome (success or failure) was selected as a dependent variable. Confounding variables included age, gender, site, smoking, diabetes, hypertension, previous graft, previous sinus lift procedure, implant system, implant length, implant diameter, immediate versus delayed placement, and past periodontal history. Study variables included the department at LSUHSC School of Dentistry and level of training. To aid in analysis, variables were expressed in binary measures, 1 corresponding to implant success and 0 corresponding to implant failure. Multiple logistic regression, comparing the implant outcome to the independent variables, was performed to establish the presence of any statistically significant associations. Multilevel logistic regression was then performed on the statistically significant associations (department, resident year of training, and implant systems). The individual clinician was used as a random variable in the model to assess any relevant finding. Clinicians were stratified into three groups based on the level of their clinical expertise. All the groups treated a similar patient population with respect to medical status, age, and gender.
Group 1 (beginners) is first-year residents in the Periodontics department and in the Prosthodontics fellowship program. At LSUHSC School of Dentistry, the Periodontics residents and Prosthodontics fellows are trained in implant placement within 6 months of their training and were exposed to a similar patient population.
Group 2 (intermediate) is second-year residents in the Periodontics department at LSUHSC School of Dentistry.
Group 3 (advanced) is third-year residents in the Periodontics and OMFS departments at LSUHSC School of Dentistry. The third year of residency was selected for both OMFS and Periodontics residents as both groups treat implant cases of similar severity at that point in their residency program.
All tests of significance were evaluated at the 5% significance level.