-The title of this presentation is … -I would like to thank and acknowledge the coauthors on this paper, Drs. Sung Chuang, Shadi Daher, Ali Muftu and Thomas Dodson.
- Make the slide reflect your comments below Today, dental implants are a widely accepted form of treatment for the edentulous patient. -As their use becomes widespread, it is apparent that questions regarding complications associated with placing dental implants remain . To date, most of the research in this field has focused on implant success , but systematic reports of implant complications and risk factors are few.
-To address this deficiency in the literature we proposed a research project with three specific aims. The first specific aim was to identify complications associated with dental implants. The second specific aim was to determine the frequency of these complications. The third aim was to determine the associated risk factors.
- We hypothesized that risk factors for implant complications can be modified by the clinician to enhance patient outcome.
-To address the specific aims for this project, we used a retrospective cohort study design. The study sample was derived from the population of patients who had one or more implants placed by clinicians at the Implant Dentistry Centre located at the Faulkner Hospital in Boston, Massachusetts, between 1992 and 2000. - When each patient contributes multiple observations to a study, the issue of correlated observations arises. In this case, each patient contributed one or more implants to the sample. Given the composition of the sample, in order to enhance statistical validity , we randomly selected one implant per patient to include in the study sample.
There were multiple variables to consider as predictors or risk factors for implant complications. The variables were grouped into several sets . The first set of variables were demographic variables and included gender and age. Medical conditions we evaluated were ASA status and tobacco use at the time of implant placement.
- Anatomic variables included implant location such as maxilla versus mandible or anterior vs. posterior position, bone quality, and the position of the implant relative to other teeth or implants. -Implant specific variables were, implant length, diameter, coating , stage, well size, as well as abutment related variables. Etc
We also looked at removable vs. fixed prostheses and the use of reconstructive procedures as potential risk factors for complications. (Reconstructive procedures included internal and lateral sinus lifts, barrier membranes, bone grafts (autologous or bone substitute), and ridge split procedures. Reconstructive procedures and implant surgeries were carried out either simultaneously or separately).
-The primary outcome variable was the presence or absence of complications. -If a complication was identified, it was characterized as inflammatory, prosthetic or operative as follows . . . Go to next slide.
- An inflammatory complication was identified if an implant was associated with: Mobility, as documented in the patient’s chart. Pain lasting 7 or more days, which required dispensation of additional pain medication and/or additional follow-up appointments. Infectious process: presence of purulent exudate, fistula, cellulitis, or sinusitis, or any pathological process which warranted treatment with antibiotics. Peri-implantitis: defined as radiographic evidence of progressive bone loss or a lucency associated with the implant. Impaired wound healing: Soft tissue break down exposing either bone or implant, occurring 21 days or more after implant delivery. Gingival recession: requiring graft procedure.
Prosthetic complications included abutment fracture and loosening, premature O-ring damage, occlusal or prosthetic adjustments, and recementation of loose prostheses.
Operative complications included: -inadvertent placement of an implant into the sinus or floor of the mouth -paresthesia (defined as the patient’s subjective complaint of numbness and/or tingling, lasting 7 or more days after implant placement).
Descriptive statistics and complication frequencies were computed with SAS statistical software. The univariate Cox proportional hazards regression model was used to identify candidate variables associated with complications. Variables associated with complications with a p-value of <0.15 were considered candidate variables for inclusion in the multivariate model. Specific risk factors for complications were identified with the multivariate Cox model (p<0.05).
The following table summarizes the descriptive statistics for the study sample. The sample population was comprised of 677 patients with an average age of 54 years old. Slightly over half of the patients were female. The vast majority of patients were heaIthy at the time of impIant surgery and fewer than 10% were medically compromised. Approximately 10% of the sample population were smokers at the time of implant surgery- highlighted variables were associated with implant complications at p < 0.15.
The jaw as well as anterior-posterior location and implant proximity were identified in the univariate model as potential risk factors for complications.
Brief description of variables : -Approximately ½ of the implants were placed in Type 4 bone.
Most implants-approximately 95%- were between 3 and 5mm in diameter and ranged from 4 to 11mm in length.
- Approximately half were hydroxyapatite coated -Most implants had a well size of 2.0mm. - Fewer than 20% of the implants were delivered using a one-stage procedure. O ne-stage implants were also identified in the univariate model as potential risk factors for complications.
- Approximately 80% of the abutments were between 3 and 5.5mm in diameter . -Almost ¾ had a 0 ° angulation.
-Over 90% of the implants supported fixed prostheses -Approximately 1/3 of the recipient sites were associated with reconstructive procedures.
-The results of our analysis showed that approximately 14% of the implants were associated with complications . About 10% of these complications were classified as inflammatory, 3% were prosthetic, and 1% were operative.
Table 1 summarizes the results of the multivariate Cox model we developed to identify risk factors associated with implant complications. Candidate variables for inclusion in the mulivariate model were derived from the univariate analyses previously presented. The variables included in the model were tobacco use, etc. After adjusting for age, gender, and prosthetic type, the variables highlighted in yellow----tobacco use, reconstructive procedures, and implant staging were statistically associated with an increased risk for implant complications. For example, tobacco use was associated with over a two-fold increased risk for complications when compared to non-smokers.
- As mentioned earlier, 10% of the implants experienced inflammatory complications: -4% of these complications were attributed to mobility and 1.6% were associated with pain. Infectious processes accounted for over 2% of inflammatory complications. -We did not scrutinize the prosthetic and operative categories in detail due to the small number of patients experiencing these complications.
Risk factors associated with inflammatory complications were the same as for Overall Complications: Smoking at the time of implant surgery, use of reconstructive procedures, use of one-stage implants. -Results show that patients who smoke at the time of implant surgery are over three times more likely to experience an inflammatory complication compared to patients who do not smoke.
-Risk factors identified for operative complications include implants placed in the maxilla and the use of reconstructive procedures. -Implants placed in the maxilla were more likely to be associated with operative complications compared to implants placed in the mandible.
The purpose of this study was to address deficiences in the literature regarding complicaitons folloing implant surgery. Our first specific aim was to identify the types of complications associcated with implant surgyer. We were able to catergorize the complicatons into infalmmatory, prosthetic, or operative. Our second specific aim was to determine the frequency of complications. The results of our study suggest that the overall complication rate is x %. The inflammatory complication rate was x, the operaritve was y and the prosthetic was z.
The third specific aim of this study was to identify risk factors assoicated with implant-related complications. Overall, x , y , and z were associated with complcaitons. For inflammatoyr complciatons,. Varialbes x, y, and z were assoicated with complicaiotn, etc. etc.
It is of note that two of the four variables identified as risk factors for complications, smoking and one-stage implants, are under the control of the clinician. These findings support our hypothesis that risk factors associated with implant complications can be modified by the clinician to enhance patient outcome. -We believe this information is of significance to the clinician for two reasons: - clinician can decrease incidence of complications with this knowledge (i.e., suggest alternative treatment for smokers, impose mandatory smoking cessation period around time of surgery). -clinician is better equipped to assist the patient in making an informed decision with this insight , allowing for selection of the most appropriate treatment option.
-It is suggested that future studies investigate the effects of smoking on implant complications ( to determine how duration and timing of abstinence influences complication rates). -Future studies regarding reconstructive procedures and implant complications are also recommended ( influence of the type and timing of reconstructive procedure on complication incidence) Thank you…Questions?... Potential questions: 1. Explanation of why no variables were identified as risk factors for prosthetic complications: This could be due to the small number of patients who experienced this type of complication, or the broad definition employed for prosthetic complication.It is also conceivable that the candidate variables in the model are simply not statistically significant risk factors for prosthetic complications. 2. Categorization of bone quality was performed at the time of implant delivery. -Determination of bone quality was based on the appearance of bone in the flutes of a reamer extracted from the osteotomy: Bone quality was categorized as type 1 if the bone completely filled the flutes of the reamer. Type four bone was defined as having minimal to no bone remaining in the flutes of the reamer after completing the osteomy. Types 2 and three bone were intermediate levels. Type 2 bone was classified as bone, associated with bleeding, filling the flutes of the reamer. Type 3 bone quality differed from Type 2 in that the extracted bone had a lower density.
Complications of Dental Implants: Identification, Frequency and Associated Risk Factors NE McDermott, BS*, S-K Chuang, DMD, MD*, VA Vehemente, BS*, S Daher, DMD † , A Muftu, DDS, MS †† , TB Dodson, DMD, MPH *‡ Harvard School of Dental Medicine * Massachusetts General Hospital ‡ Boston University Goldman School of Dental Medicine † Tufts University School of Dental Medicine ††