The design and initial implementation of a surgical

Expansion of a Predoctoral Surgical Implant Selective for Dental Students Stefanie D. Seitz, DDS; Richard L. Zimmermann, DDS; William D. Hendricson, MA, MS Abstract: Historically, predoctoral dental education programs have focused on the restoration of implants in the clinical environment; however, given the increase in dental implant therapy being performed by general dentists, the need to incorporate surgical implant training is becoming evident. This article describes a predoctoral surgical implant selective at the University of Texas Health Science Center at San Antonio and its evolution across five years to include emerging techniques and technology to enhance students understanding of dental implant therapy, both surgical and restorative. From virtual implant planning and guided surgery to intra-oral scanning of implants for custom abutments and restorations, students obtained first-hand experiences with a wide spectrum of aspects of implant therapy. The results of anonymous surveys completed by 2014-15 students before and after the year-long selective regarding their impression of the program are also discussed. Dr. Seitz is Assistant Clinical Professor of Comprehensive Dentistry, School of Dentistry, University of Texas Health Science Center at San Antonio; Dr. Zimmermann is Assistant Clinical Professor of Comprehensive Dentistry, School of Dentistry, University of Texas Health Science Center at San Antonio; Mr. Hendricson is Assistant Dean, Educational and Faculty Development, School of Dentistry, University of Texas Health Science Center at San Antonio. Direct correspondence to Dr. Stefanie Seitz, School of Dentistry, University of Texas Health Science Center at San Antonio, 8210 Floyd Curl Drive, Mail Code 7914, San Antonio, TX 78229; 210-567-3450; seitz@uthscsa.edu. Keywords: dental education, dental implants, surgical dental prosthesis Submitted for publication 5/15/15; accepted 8/7/15 The design and initial implementation of a surgical implant educational program for dental students at the University of Texas Health Science Center at San Antonio School of Dentistry (UTHSCSA SOD) were described by Zimmermann and Hendricson in 2011. 1 The selective was created to augment other implant courses, incorporating classroom and simulation lab components that students receive in the second, third, and fourth years of the UTHSCSA SOD curriculum. The selective has also evolved in concordance with Commission on Dental Accreditation (CODA) standard 2-23h (regarding replacement of teeth including fixed, removable, and dental implant prosthodontic therapies) as an element of the school s curricular response to this standard. 2 This article describes the expansion of this predoctoral surgical implant selective over the past several years through the integration of emerging technologies that facilitated an increase in students dental implant knowledge and enhanced their implant planning, surgical placement, and implant restorative experiences. The purpose of this article is to share one school s strategies for integrating clinical implant experiences into its predoctoral curriculum. It also reports students assessment of this course in one year with a focus on approaches recently blended into the course. Program Description The selective began in 2009 with four trained faculty members and nine senior students chosen from applicants who had submitted a curriculum vitae, letter of intent, and faculty recommendation. As Zimmermann and Hendricson explained, by limiting the number of students, concerns regarding equipment, patient pool, and faculty-student ratio became manageable. 1 Faculty training included a three-day course consisting of both didactic and patient-simulated laboratory sessions and placement of implants for patients in the graduate periodontics program, followed by placement of implants in the General Dentistry Clinic. In the original format, the initial portion of the selective occurred in the summer break before students started their senior year. The summer portion of the course consisted of two weeks of lectures, case presentations, and simulation (surgery on models). Topics for the lectures included diagnosis and treatment planning, surgical evaluation, and implant surgery. For the clinical aspect of the course, students performed implant surgeries in the fall semester during their unscheduled afternoon. The implant surgical team consisted of four individuals: the surgeon, an assistant, a photographer, and a supervising faculty 328 Journal of Dental Education Volume 80, Number 3

member. The students performed all aspects of the surgery under the close guidance of a trained faculty member. For most cases, other students in the selective acted as assistants or took surgical photographs and/or radiographs, thus increasing their exposure to implant surgery. All cases were documented with photographs taken by another student enrolled in the selective, providing yet another method of exposure to different types of implant surgeries and collaborative learning among participating students as well as supporting post-surgery debriefings. 1 In 2014, the selective began in a different way. The number of students participating increased to 16 with two supervising general dentistry faculty members who had received extensive implant training. Intra-oral scanners were incorporated into the course including Planscan (Planmeca, Roselle, IL, USA), CEREC Bluecam (Sirona, Charlotte, NC, USA), and True definition (3M, St. Paul, MN, USA) for diagnostic and restorative functions. The summer portion of the course consisted of only one week of lectures, case presentations, and simulation and was followed by a second week of surgical implant placements by the students. In preparation for surgery, students viewed cone beam computed tomography (CBCT) files (DICOM file) in a virtual three-dimensional implant planning software, codiagnostix 9 (Dental Wings, Montreal, Canada) that allowed for greatly enhanced visualization of bone, critical anatomy, and restorative plans. 3 In order to fully utilize the software and its capabilities, the students took digital impressions of the patient or patient model and created a virtual model or surface scan (Figure 1) in the form of a standard tessellation language (STL) file. An STL file is the format widely used for rapid prototyping and computer-aided manufacturing. In addition to this STL file, the students created another STL file of a virtual crown, designed with the aid of computer-aided design/computer-aided manufacturing (CAD/CAM) software, in the proposed implant site to identify the best implant diameter/length and the best location for the implant placement. The surface scan and crown were then imported (Figure 2) into implant planning software to assist in determining the ideal implant (type, diameter, length) and location for implant placement. Figure 1. Screenshot of surface scan Figure 2. Occlusal view of surface scan fused to virtual model rendered from CBCT (left): imported virtually designed crown (right) March 2016 Journal of Dental Education 329

Figure 3. Virtually designed surgical guide (left) and surgical guide utilized for implant placement (right) Figure 4. Scanbody in place for intraoral scan The surface scan was combined or fused to the virtual model from the CBCT 3D data (Figure 2). This process enabled the students to ensure that their implant planning was prosthetically driven. This fusion also allows for a digital surgical drill guide (Figure 3) to be designed and exported for rapid prototyping (3D printing). The virtually designed surgical guide then aids the student during the placement of the implant(s). During the second week, 17 implants were placed during 15 surgeries by 14 students. These surgeries were accomplished by applying three methods. The method chosen for each surgery was decided by the supervising faculty member based on the case and the method determined best suited for the implant site. One method exclusively used the digital drill guide for the osteotomy and implant placement and allowed for a guided flapless surgery. Another method required students to perform the entire surgery conventionally, from creating the flap to placing the implant. The third method was a hybrid in which the digital drill guide was utilized for the initial osteotomy and then the student completed the surgery in the traditional method without it. This final method was necessary if the surgical site only allowed for the smaller diameter sleeve but the implant diameter required drills past the initial drill. After the appropriate healing time, the patients returned to begin the restorative phase of treatment. At this time, the students were able to take advantage of the use of a digital scanning system that allowed for a new all-digital workflow that enabled them to simply place a scanbody on the implant (Figure 4) and take an intraoral scan of the patient, including both arches and a buccal bite scan for articulation. The scanbody indicated the position and orientation of the implant to aid CAD/CAM software in the design and fabrication of the final restoration. The digital impressions and prescription were then virtually submitted to the dental laboratory through a trusted connection, which is a verified workflow for customized abutments and restorations. Both screw-retained and cement-retained restorations were placed so that the students were exposed to both methods of restorations. The cement-retained restorations were cemented on custom titanium abutments with the gingival margin 0.5 mm or even with the gingival crest, making cement removal easier 330 Journal of Dental Education Volume 80, Number 3

and minimizing the likelihood of cement remaining around the margin after cementation. The survival rate of the implants placed during the summer portion of the program was 6%, a favorable result. 4 Throughout the academic year, the students continued to plan, surgically place, and restore implants. A newly released digital impression system, Trios Pod (3Shape, Warren, NJ, USA) was introduced and used to restore various implant systems. Digital technology was introduced into the selective with the expectation that its use would be focused on implants. However, the students expanded their use of technology into daily clinical activities. As a whole, they completed 125 digital scans for 142 crown/bridge units and 66 implant restorations during their senior year. In addition to the technologies previously mentioned, a new CAD/CAM design software, CARES 9.5 (Straumann, Andover, MA, USA), was introduced in the spring semester that allowed for virtually designed dental prosthesis from single unit restorations to implant bars. Students were then able to visualize how the actual position of the implant affects restorative options. This software also enabled students to design the restorations that would be fabricated for their patients. In addition, the software has a portal that allows for communication with the implant planning software in real time to aid in implant planning. Program Evaluation As one informal way of evaluating the effect the changes had on the selective, the students in academic year 2014-15 were asked to complete a survey at the beginning of the program and again at the end. This research was approved by the Institutional Review Board for the University of Texas Health Science Center at San Antonio on May 11, 2015. Of the 16 students in the selective, 15 completed the pre survey, and 12 completed the post survey. Statistical analysis was done by chi-square. Regarding implant therapy (Table 1), there were statistically significant increases between pre-selective and post-selective responses for students self-assessment of knowledge, participation in implant treatment, and comfort in restoring implants. Table 2 for CAD/CAM indicates similar statistically significant increases from pre to post assessment for knowledge and clinical experience. In addition to these responses, students were surveyed as to whether they had achieved their goals for the selective. The responses were positive and included insights into the students perspectives on the selective, implant therapy, and patient care in general. The students reported expanded knowledge and confidence about implants, often mentioned learning to think outside the box, and stated the course reinforced that the most important part of the treatment was the actual treatment planning beforehand and being prepared as well. In addition, students responded that the course helped them look at implant treatment differently and reinforced the importance of keeping up-to-date with current literature. With regard to CAD/CAM, students indicated that they gained increase knowledge and appreciated their first-hand experience in intraoral scanning. Discussion Several observations associated with the different surgical methods emerged during case planning discussions and treatment debriefings among students and faculty. One notable observation was the decreased post-operative pain experienced by patients receiving the flapless, completely guided implant placement. These patients rarely reported need for anything beyond ibuprofen and acetaminophen directly following the surgery. Parmigiani- Izquierdo et al. reported that postoperative pain was significantly more intense after surgery with the conventional flap technique than after surgery with the atraumatic flapless technique. 5 Those investigators also reported that the inflammatory response was more intense with the flap technique. A systemic review by Hultin et al. concluded that flapless guided surgery is likely to decrease pain and discomfort in the immediate postoperative period, a substantial clinical advantage. 6 A second notable observation related to the dental students perception that guided surgery would be uncomplicated in comparison to other methods. However, following the guided surgeries, students realized that it was not as straightforward as they had previously thought. In fact, two studies found that the clinical demands in guided surgery were no less than during conventional implant placement surgery and that care should be taken whenever applying this technique on a routine basis. 6,7 Another study found that deviations from planned implant positions existed in the coronal and apical portions of the implants as well as with implant angulation; mean deviations were less than 2 mm in any direction and March 2016 Journal of Dental Education 331

Table 1. Dental students pre- and post-course self-assessment of implant knowledge, clinical experiences, and comfort level, by number selecting each response (pre n=15; post n=12) Implant Knowledge Level Poor Average Excellent Mean; SD 2 sample T Diagnosis and treatment planning Pre 1 12 1 2.07; 0.46 T: 2.717 Post 0 5 7 2.58; 0.51 p=0.012 Surgical placement Pre 9 6 0 1.40; 0.52 T: 5.134 Post 0 7 5 2.42; 0.51 p=0.0001 Restoration of implants Pre 6 8 1 1.67; 0.62 T: 5.979 Post 0 2 10 2.83; 0.39 p=0.0001 Implant Surgeries Observed or Participated In None 1-2 3-5 5+ Mean; SD 2 sample T Pre 1 6 5 3 2.93; 1.68 T: 2.601 Post 0 1 5 6 4.29; 1.01 p=0.016 Implants Restored None 1-2 3-5 5+ Mean; SD 2 sample T Pre 10 3 2 0 0.83; 1.42 T: 7.664 Post 0 1 3 8 4.46; 1.03 p=0.0001 Not Very Very Comfort in Implant Restoration Comfortable Comfortable Comfortable Mean; SD 2 sample T Posterior single units Pre 10 4 1 1.40; 0.63 T: 7.230 Post 0 2 10 2.83; 0.39 p=0.0001 Anterior single units Pre 13 1 1 1.40; 0.52 T: 5.134 Post 3 5 4 2.42; 0.51 p=0.0001 Multiple units Pre 14 0 1 1.67; 0.62 T: 5.979 Post 2 5 5 2.83; 0.39 p=0.0001 Implant bridges Pre 13 2 0 1.13; 0.35 T: 3.472 Post 3 6 3 2.00; 0.21 p=0.0022 Note: Wording of questions, in order, was as follows: How would you rate your knowledge level with regard to implants? How many implant surgeries have you observed or participated in? How many implants have you restored? How comfortable are you restoring implant restorations? less than 8 degrees. 8 The same principles utilized in traditional implant surgery need to be kept in mind during guided surgery. Therefore, it is imperative that students are taught various methods of surgery. In addition, it was noted that the ability to virtually plan an implant placement aided the students in visualizing the surgical site and preferred location of the implant, so that the students were able to grasp surgical concepts and be more comfortable during the surgery. Previous research found that the preoperative experience of virtually planning the approach was helpful during the operative procedures. 9 Conclusion Due to the popularity of the selective and the quality of the treatment outcomes for patients, the school s administration decided to continue with the expanded program utilizing various technologies and increase the number of accepted students to 26 for the 2015-16 academic year. The selective has been enabled by technology to proceed and expand with few faculty members by enhancing students abilities and by improving diagnosis and surgical treatment. Technology is moving forward rapidly in dentistry 332 Journal of Dental Education Volume 80, Number 3

Table 2. Dental students pre- and post-course self-assessment of CAD/CAM knowledge and clinical experiences, by number selecting each response (pre n=15; post n=12) CAD/CAM Knowledge Level Poor Average Excellent Mean; SD 2 sample T Diagnosis and treatment planning Pre 7 7 1 1.60; 0.63 T: 7.004 Post 0 1 10 2.91; 0.30 p=0.0001 Intraoral scanning Pre 7 7 1 1.60; 0.63 T: 5.976 Post 0 2 9 2.82; 0.40 p=0.0001 Placement of CAD/CAM restorations Pre 7 7 1 1.60; 0.63 T: 7.004 Post 0 1 10 2.91; 0.30 p=0.0001 CAD/CAM Restorations Diagnosed and Treatment Planned None 1-2 3-5 5+ Mean; SD 2 sample T Pre 8 4 2 1 1.27; 1.73 T: 6.225 Post 0 1 0 10 4.68; 1.05 p=0.0001 Digital Scans/Impressions None 1-2 3-5 5+ Mean; SD 2 sample T Scan of model Pre 2 10 3 0 2.93; 1.68 T: 2.601 Post 0 2 1 8 4.29; 1.01 p=0.016 Intraoral scan Pre 11 4 0 0 0.40; 0.687 T: 8.44 Post 0 2 1 8 4.27; 0.423 p=0.0001 CAD/CAM Restorations Placed None 1-2 3-5 5+ Mean; SD 2 sample T Pre 8 5 1 1 1.27; 1.73 T: 6.225 Post 0 1 0 10 4.68; 1.05 p=0.0001 Note: Wording of questions, in order, was as follows: How would you rate your knowledge level with regard to CAD/CAM? How many CAD/CAM restorations have you diagnosed and treatment planned? How many digital scans/impressions have you done? How many CAD/CAM restorations have you placed? and is an extremely useful aid with regard to implants. The selective has been able to greatly expand what students learn and how they learn it with the implementation of these technologies and will continue to expand as more advanced options become available. REFERENCES 1. Zimmermann R, Hendricson WD. Introduction of an implant surgical selective into a predoctoral dental curriculum. J Dent Educ 2011;75(9):1256-62. 2. Commission on Dental Accreditation. Accreditation standards for dental education programs. Chicago: American Dental Association, 2013. 3. Scherer MD. Presurgical implant-site assessment and restoratively driven digital planning. Dent Clin North Am 2014;58(3):561-95. 4. Guo Q, Lalji R, Le AV, et al. Survival rates and complication types for single implants provided at the Melbourne Dental School. Aust Dent J 2014;27. 5. Parmigiani-Izquierdo JM, Sánchez-Pérez A, Cabaña- Muñoz ME. A pilot study of postoperative pain felt after two implant surgery techniques: a randomized blinded prospective clinical study. Int J Oral Maxillofac Implants 2013;28(5):1305-10. 6. Hultin M, Svensson KG, Trulsson M. Clinical advantages of computer-guided implant placement: a systematic review. Clin Oral Implants Res 2013;23(Suppl 6):124-35. 7. D haes J, Van De Velde T, Komiyama A, et al. Accuracy and complications using computer-designed stereolithographic surgical guides for oral rehabilitation by means of dental implants: a review of the literature. Clin Implant Dent Relat Res 2012;14(3):321-35. 8. Valente F, Schiroli G, Sbrenna A. Accuracy of computeraided oral implant surgery: a clinical and radiographic study. Int J Oral Maxillofac Implants 2009;24(2):234-42. 9. Ferroli P, Tringali G, Acerbi F, et al. Advanced 3-dimensional planning in neurosurgery. Neurosurgery 2013;72(Suppl 1):54-62. March 2016 Journal of Dental Education 333