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Poster 10: Highly Nonlinear Solitary Waves for the Assessment of Dental Implant Stability
Poster Session At 4 weeks, patient presented with mild swelling below the chin not extending past the hyoid bone. She denied fevers or chills and was maintaining her own airway without any distress. Upon physical examination, there was firm but fluctuant edema with urticaria and erythema along the submental region without tenderness to palpation. Lymphadenopathy was also present. No other signs of urticaria, edema, and erythema noted elsewhere on the face or torso. Submental aspirate collections revealed 1.5mL of pink, clear fluid, which flattened the submental region. Aspirate was sent for cultures, and the patient was prescribed antibiotics and a steroid dose-pack. At 6 weeks, surgical exploration was performed via submental incision and midline platysma-plication sutures were removed. Initial thought was that the patient experienced an allergic reaction to the silk suture. Surgical exploration was uneventful which noted no obvious granulation formations, except for thin, serous fluid. A biopsy was performed and submitted for pathology. Cultures and gram stain were negative, and the patient appeared to respond well to the steroid dose-pack. Pathology reported chronic inflammatory infiltrates. Over the next 6 months, erythema and swelling were evident but gradually subsided while surgical incisions healed well. Patient’s symptoms eventually resolved completely without any further events. Type-I reactions to aprotinin are well documented in the literature. It is important to note that reactions related to aprotinin use involved mostly intravascular administration and a previous history of exposure.3 Other case reports describe anaphylactic reactions to fibrin sealants after topical application.4 On this patient, fibrin sealant was applied topically, but the symptoms clinically resembled a delayed hypersensitivity reaction. This is the first recorded incident of a type-IV hypersensitivity to fibrin sealant use in facelift surgery. References: Fezza J, et al. The Use of Fibrin Sealant in Facelift Surgery. Am J Cosmetic Surg 2002 Nov 4;19:219-221. Fattahi T, et al. Clinical Applications of Fibrin Sealants. J Oral Maxillofac Surg 2004;62:218-224. Beierlein W, et al. Forty Years of Clinical Aprotinin Use: A Review of 124 Hypersensitivity Reactions. Ann Thorac Surg 2005;79:741-748. Shirai T, et al. Anaphylaxis to Aprotinin in Fibrin Sealant. Internal Medicine 2005 Nov 10;44:1099-1089.
DENTAL IMPLANTS POSTER 10 Highly Nonlinear Solitary Waves for the Assessment of Dental Implant Stability R. P. Shupak: University of Pittsburgh Medical Center The use of endosseus dental implants has dramatically increased over the last decade. Methods to assess stabilAAOMS • 2012
ity and bone-implant interface during healing have yet to be standardized. Currently there are few commercially developed systems that adequately determine implant stability. Although radiographs are useful for monitoring dental implant healing and maintenance, they cannot be used alone. Ideally a non-destructive and minimally invasive technique to determine implant stability would benefit both practitioner and patient. The purpose of this study is to quantify implant stability utilizing highly nonlinear solitary waves (HNSWs).1 In this study we hypothesized that the reflection of HNSWs interacting with an implant is affected by the progression of the osseointegration process2. We propose that the stability of a dental implant inserted into a living bone can be assessed by observing the propagation of the solitary waves within a chain of spherical particles in contact with the prosthetic apparatus. Our final goal is to develop a noninvasive approach that can accurately and consistently assess the osseointegration progress enabling surgeons to determine when adequate healing or osseointegration occurs. An in vitro experiment was developed utilizing HNSWs to monitor the reverse osseointegration process. Implants (4.3 ⫻ 13mm) were placed into bovine bone model at ⱖ 40 Ncm. A unique HNSW transducer was attached to a prosthetic abutment. The HNSW transducer-abutment produced and monitored wave reflection properties. The implant and bone complex was immersed in a 67% nitric acid bath and transducer recordings were made at the time of initial placement and at 15-minute intervals for 13 hours. Additionally, aliquots from the acid bath were sampled every two hours and calcium quantified using an atomic absorption spectrometer to assess bone degradation. The data were analyzed by plotting the amplitude ratio of the primary solitary wave as a function of the monitoring time which was normalized with respect to the averaged data taken at the baseline. A linear decrease of the normalized ratio was clearly visible by the end of the monitoring period, the ratio decreased by approximately 90%. A strong correlation was found between stability and certain characteristics of HNSWs. These wave form pattern shifts also corresponded to the leaching out of calcium. The use of HNSWs provides unique advantages over other established systems. Multiple characteristics of reflected HNSWs can be quantified and analyzed to determine implant stability through a non-destructive modality. The research presented will be instrumental in developing clinical trials of a novel, non-invasive protocol to determine implant stability and detection of failing or compromised implants so that therapeutic interventions can be undertaken in a timely manner. The vision is to eventually develop a “smart” abutment to monitor implant stability. References: Yang, J., Silvestro, C., Khatri, D., De Nardo, L., Daraio, C., 2011, “Interaction of Highly Nonlinear Solitary Waves with Linear Elastic Media,” Phys. Rev. E, 83, 046606.
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Poster Session Ni, X., Nassiri, S., Rizzo, P., and Vandenbossche, J., 2011, “Highly Nonlinear Solitary Waves-based sensor for Monitoring Concrete,” Proc. SPIE’s, 7981, 79812L, doi:10.1117/12.880280.
POSTER 11 Electromechanical Impedance Method to Assess Dental Implant Stability T. Li: University of Pittsburgh School of Dental Medicine, A. Tabrizi Electromechanical Impedance Method to Assess Dental Implant Stability Oral and maxillofacial implants restore functionality and esthetics for fully and partially edentulous patients. While traditional surgical protocol is a two-stage procedure, single-stage procedures have gained interest in order to decrease treatment time and cost. Since longterm prognosis of load bearing implants depends on osseointegrated implant stability, a reliable and noninvasive method to assess stability is necessary. In addition to X-rays, CT scans, and MRIs, non-destructive biomechanical models are utilized to supplement imaging techniques. The purpose of this study is to evaluate the Electro-Mechanical Impedance (EMI) method as a novel way to assess implant stability.1 We propose that bonded piezoceramic transducers (PZTs) can be used to evaluate structural health of invitro implants in bovine bone.2 Since structural vibrations depend on the mechanical impedance of the host, we hypothesize that progression of the osseointegration process will affect PZT electrical conductance. In our model, we used cortical bone from extremities and costal bone as host structures. 4.3 mm by 13 mm implants were placed at3 40 Ncm. Custom cut Piezoceramic transducers at 2x2x0.267 mm were bonded to the implant abutments. Agilent E4980A LCR meter and Data Acquisition Switch Unit were used to measure PZT admittance. Bone samples with implants were immersed in a glass container with nitric acid solution ([w/w] ⫽ 6770%). Conductance measurements were recorded hourly for 10 hours. Baseline signatures were measured immediately after immersing samples in acid. Additionally, calcium loss was quantified using atomic absorption spectrometer (ASS) by diluting 5 ml of acid solution at 1000x in deionized water every 2 hours. To evaluate data for 10 hours, PZT conductance as a function of frequency at baseline, 5, and 10 hours upon acid solution immersion was plotted for both samples. We also used the root-mean-square-deviation (RMSD) and the root-mean-square (RMS) indices to statistically quantify the EMI measurements. Results show a similar trend in both samples. As bone degradation progressed, PZT conduction increased at 5 and 10 hours compared to baseline. Smaller structural peaks in the PZT conduction plot showed a monotonic increase in both samples. e-46
When the RMSD and RMS of the conductance as a function of monitoring time were analyzed, a monotonic variation with respect to the progression of bone degradation was observed. In this study, we evaluated the variation of the structural impedance of the PZT-implant-bone system using the conductance slope, RMSD, and RMS of the conductance plots with respect to time. When compared to the amount of calcium loss measured using an atomic absorption spectrometer, a correlation between the EMI-based features and calcium loss was noted. Using the EMI method to evaluate structural health of dental implants shows promising results as a viable tool for surgeons to evaluate implant stability through a non-invasive manner. Further directions of using EMI method in implant evaluation include: test this approach for repeatability; develop a model on in vivo samples; and compare with other non-invasive biomechanical testing systems. The goal is to develop a commercially available and sensitive tool to evaluate implant stability and enhance oral rehabilitation care. References: Annamdas VGM, Rizzo P. 2009 Influence of the excitation frequency in the electromechanical impedance method for SHM applications. Proc of SPIE 7293 72930V DOI:10.1117/12.815366. Bhalla S, Bajaj S. 2008 Bone characterization using piezo transducers as biomedical sensors. Strain 44 475-78.
POSTER 12 Short Dental Implants: Indications and Outcomes P. Boffano: University of Turin, P. Smurra, C. Gallesio Statement of the Problem: Short implants can be used as an alternative treatment method to bone grafting procedures in dental implantology. The purpose of this study was to assess the outcomes and the implant survival rate of short (ⱕ9 mm) dental implants installed in a consecutive series of patients with severe alveolar resorption. Materials and Methods: A prospective cohort study design was used. Sixty-seven patients with a total of 76 short (ⱕ9 mm) dental implants were included in the study. The following data for the enrolled patients were considered: age, gender, implant length, implant diameter, site of implant, site of the short implant within the final fixed prosthetics, and implant survival after 2 years. Failure was defined as implant removal due to loss of integration or implant mobility. Panoramic radiographs were analyzed for periimplant marginal bone loss. Methods of Data Analysis: Descriptive statistics. Results: On the whole, 18 9-mm implants and 58 8-mm implants were placed. The most frequent implant AAOMS • 2012
DENTAL IMPLANTS POSTER 10 Highly Nonlinear Solitary Waves for the Assessment of Dental Implant Stability R. P. Shupak: University of Pittsburgh Medical Center The use of endosseus dental implants has dramatically increased over the last decade. Methods to assess stabilAAOMS • 2012
ity and bone-implant interface during healing have yet to be standardized. Currently there are few commercially developed systems that adequately determine implant stability. Although radiographs are useful for monitoring dental implant healing and maintenance, they cannot be used alone. Ideally a non-destructive and minimally invasive technique to determine implant stability would benefit both practitioner and patient. The purpose of this study is to quantify implant stability utilizing highly nonlinear solitary waves (HNSWs).1 In this study we hypothesized that the reflection of HNSWs interacting with an implant is affected by the progression of the osseointegration process2. We propose that the stability of a dental implant inserted into a living bone can be assessed by observing the propagation of the solitary waves within a chain of spherical particles in contact with the prosthetic apparatus. Our final goal is to develop a noninvasive approach that can accurately and consistently assess the osseointegration progress enabling surgeons to determine when adequate healing or osseointegration occurs. An in vitro experiment was developed utilizing HNSWs to monitor the reverse osseointegration process. Implants (4.3 ⫻ 13mm) were placed into bovine bone model at ⱖ 40 Ncm. A unique HNSW transducer was attached to a prosthetic abutment. The HNSW transducer-abutment produced and monitored wave reflection properties. The implant and bone complex was immersed in a 67% nitric acid bath and transducer recordings were made at the time of initial placement and at 15-minute intervals for 13 hours. Additionally, aliquots from the acid bath were sampled every two hours and calcium quantified using an atomic absorption spectrometer to assess bone degradation. The data were analyzed by plotting the amplitude ratio of the primary solitary wave as a function of the monitoring time which was normalized with respect to the averaged data taken at the baseline. A linear decrease of the normalized ratio was clearly visible by the end of the monitoring period, the ratio decreased by approximately 90%. A strong correlation was found between stability and certain characteristics of HNSWs. These wave form pattern shifts also corresponded to the leaching out of calcium. The use of HNSWs provides unique advantages over other established systems. Multiple characteristics of reflected HNSWs can be quantified and analyzed to determine implant stability through a non-destructive modality. The research presented will be instrumental in developing clinical trials of a novel, non-invasive protocol to determine implant stability and detection of failing or compromised implants so that therapeutic interventions can be undertaken in a timely manner. The vision is to eventually develop a “smart” abutment to monitor implant stability. References: Yang, J., Silvestro, C., Khatri, D., De Nardo, L., Daraio, C., 2011, “Interaction of Highly Nonlinear Solitary Waves with Linear Elastic Media,” Phys. Rev. E, 83, 046606.
e-45
Poster Session Ni, X., Nassiri, S., Rizzo, P., and Vandenbossche, J., 2011, “Highly Nonlinear Solitary Waves-based sensor for Monitoring Concrete,” Proc. SPIE’s, 7981, 79812L, doi:10.1117/12.880280.
POSTER 11 Electromechanical Impedance Method to Assess Dental Implant Stability T. Li: University of Pittsburgh School of Dental Medicine, A. Tabrizi Electromechanical Impedance Method to Assess Dental Implant Stability Oral and maxillofacial implants restore functionality and esthetics for fully and partially edentulous patients. While traditional surgical protocol is a two-stage procedure, single-stage procedures have gained interest in order to decrease treatment time and cost. Since longterm prognosis of load bearing implants depends on osseointegrated implant stability, a reliable and noninvasive method to assess stability is necessary. In addition to X-rays, CT scans, and MRIs, non-destructive biomechanical models are utilized to supplement imaging techniques. The purpose of this study is to evaluate the Electro-Mechanical Impedance (EMI) method as a novel way to assess implant stability.1 We propose that bonded piezoceramic transducers (PZTs) can be used to evaluate structural health of invitro implants in bovine bone.2 Since structural vibrations depend on the mechanical impedance of the host, we hypothesize that progression of the osseointegration process will affect PZT electrical conductance. In our model, we used cortical bone from extremities and costal bone as host structures. 4.3 mm by 13 mm implants were placed at3 40 Ncm. Custom cut Piezoceramic transducers at 2x2x0.267 mm were bonded to the implant abutments. Agilent E4980A LCR meter and Data Acquisition Switch Unit were used to measure PZT admittance. Bone samples with implants were immersed in a glass container with nitric acid solution ([w/w] ⫽ 6770%). Conductance measurements were recorded hourly for 10 hours. Baseline signatures were measured immediately after immersing samples in acid. Additionally, calcium loss was quantified using atomic absorption spectrometer (ASS) by diluting 5 ml of acid solution at 1000x in deionized water every 2 hours. To evaluate data for 10 hours, PZT conductance as a function of frequency at baseline, 5, and 10 hours upon acid solution immersion was plotted for both samples. We also used the root-mean-square-deviation (RMSD) and the root-mean-square (RMS) indices to statistically quantify the EMI measurements. Results show a similar trend in both samples. As bone degradation progressed, PZT conduction increased at 5 and 10 hours compared to baseline. Smaller structural peaks in the PZT conduction plot showed a monotonic increase in both samples. e-46
When the RMSD and RMS of the conductance as a function of monitoring time were analyzed, a monotonic variation with respect to the progression of bone degradation was observed. In this study, we evaluated the variation of the structural impedance of the PZT-implant-bone system using the conductance slope, RMSD, and RMS of the conductance plots with respect to time. When compared to the amount of calcium loss measured using an atomic absorption spectrometer, a correlation between the EMI-based features and calcium loss was noted. Using the EMI method to evaluate structural health of dental implants shows promising results as a viable tool for surgeons to evaluate implant stability through a non-invasive manner. Further directions of using EMI method in implant evaluation include: test this approach for repeatability; develop a model on in vivo samples; and compare with other non-invasive biomechanical testing systems. The goal is to develop a commercially available and sensitive tool to evaluate implant stability and enhance oral rehabilitation care. References: Annamdas VGM, Rizzo P. 2009 Influence of the excitation frequency in the electromechanical impedance method for SHM applications. Proc of SPIE 7293 72930V DOI:10.1117/12.815366. Bhalla S, Bajaj S. 2008 Bone characterization using piezo transducers as biomedical sensors. Strain 44 475-78.
POSTER 12 Short Dental Implants: Indications and Outcomes P. Boffano: University of Turin, P. Smurra, C. Gallesio Statement of the Problem: Short implants can be used as an alternative treatment method to bone grafting procedures in dental implantology. The purpose of this study was to assess the outcomes and the implant survival rate of short (ⱕ9 mm) dental implants installed in a consecutive series of patients with severe alveolar resorption. Materials and Methods: A prospective cohort study design was used. Sixty-seven patients with a total of 76 short (ⱕ9 mm) dental implants were included in the study. The following data for the enrolled patients were considered: age, gender, implant length, implant diameter, site of implant, site of the short implant within the final fixed prosthetics, and implant survival after 2 years. Failure was defined as implant removal due to loss of integration or implant mobility. Panoramic radiographs were analyzed for periimplant marginal bone loss. Methods of Data Analysis: Descriptive statistics. Results: On the whole, 18 9-mm implants and 58 8-mm implants were placed. The most frequent implant AAOMS • 2012