The International Journal of Prosthodontics

The International College of Prosthodontists (ICP) offers its members exceptional biennial meetings in carefully selected locations that reflect the College's global educational commitment. The 1991 Hiroshima meeting was a very memorable one and provided many of us with the unique opportunity to enjoy Japan and make friends with numerous Japanese colleagues whose career trajectories have profoundly impacted scholarship in the discipline. Professor Akagawa's recognized leadership and scholarship eventually led to his ICP co-presidency with Dr Patrick Lloyd, and recently culminated in the retirement from his long-term tenure as Professor and Chairman at Hiroshima University. I invited two of his long-term friends and associates, Professors Kiyoshi Koyano and Yoshinobu Maeda, to undertake this interview assignment for our international readership. Both gentlemen have already served our ICP and this journal with distinction; and Dr Koyano shared the ICP presidency with Dr Regina Mericske-Stern from 2005 to 2007, while Dr Maeda is currently sharing his ICP presidency with Dr Martin Gross. All of us who have enjoyed a warm friendship with Yasumasa Akagawa wish him and his wife much happiness and serenity for many years ahead.

The published literature describing clinical evidence used in treatment decisionmaking for the management of tooth loss continues to be characterized by a lack of consistent outcome measures reflecting not only clinical performance but also a range of patient concerns. Recognizing this problem, an international group of clinicians, educators, and scientists with a focus on prosthodontics formed the Oral Rehabilitation Outcomes Network (ORONet) to promote strategies for improving health based on comprehensive, patient-centered evaluations of comparative effectiveness of therapies for oral rehabilitation. An initial goal of ORONet is to identify outcome measures for prosthodontic therapies that represent multiple domains with patient relevance, are amenable to utilization in both institutional and practice-based environments, and have established validity. Following a model used in rheumatology, the group assessed the prosthodontic literature, with an emphasis on implantbased therapies, for outcomes related to longevity and functional, psychologic, and economic domains. These systematic reviews highlight a need for further development of standardized outcomes that can be integrated across clinical and research environments.

The Oral Rehabilitation Outcomes Network (ORONet) Longevity Working Group undertook a search of the literature from 1995 to 2009 on randomized controlled trials related to longevity of osseointegrated implants. Outcomes measures used in these studies were identified and subjected to the OMERACT component criteria of truth, validity, and feasibility. Through this process, it was a challenge to identify clinical outcomes measures that fully met the criteria. An attenuated version of the component criteria was applied, and clinical measures were identified for implant outcomes, prosthetic outcomes, and indices. A recommendation on standardized reporting periods was also presented for future consideration. The endpoint of the evaluation process is to develop consensus on clinical outcomes measures that can be applied across broad populations for osseointegrated implant care. The present ORONet initiative represents a beginning toward continual improvement and consensus development for clinical outcomes measures for osseointegrated implants.

This in vitro study analyzed the reverse torque (RevT) of abutment screws following different cleaning treatments. A convenience sample of 50 customized titanium abutment screw complexes was divided into five groups: cleaning by steam (control group), cleaning by Argon plasma (test groups 1 and 2 [with chlorhexidine gel]), and replacement of old screws with new ones (test groups 3 and 4 [with chlorhexidine gel]). Abutments were screwed onto implants and tested for RevT. The RevT of the test groups was significantly higher than that of the control group. No statistically significant difference between test groups was noted except between groups 2 and 3.

Purpose: The aim of this study was to validate the use of a mandibular repositioner appliance (MRA) to treat obstructive sleep apnea (OSA) and primary snoring, comparing polysomnographic and Epworth Sleepiness Scale (ESS) data obtained prior to and during MRA treatment. Materials and Methods: Sixty-three patients who presented with different degrees of OSA severity or primary snoring were fitted to a PM positioner between 2009 and 2011. The diagnosis was established by a polysomnogram (PSG) prior to treatment and after 6 months to verify the efficacy of MRA therapy. Subjective daytime sleepiness was evaluated by ESS questionnaire prior to treatment and at the follow-up. Results: Patients were divided into primary snoring and OSA groups. For the primary snoring group, PSG variables did not show significant results, except for a decrease in snoring. For the OSA group, the mean apnea-hypopnea index (AHI) was reduced from 23.0 ± 11 to 5.3 ± 4.0 and median ESS reduced significantly from 13.0 to 8.5. Complete response (AHI 5) was found in 25 (40%) patients and partial response (AHI = 10) in 27 (43%) patients. Conclusion: The findings validate the efficacy of the adjustable PM positioner for the safe treatment of OSA.

The purpose of this study was to examine the influence of reinforcing the structure of an overdenture on stress distribution in the residual ridge using the threedimensional finite element method. Four models of mandibular overdentures with various reinforcement methods were analyzed, including (1) without reinforcement, (2) with chrome-cobalt reinforcing wire, (3) with a reinforcing structure (a cast metal framework) and no reinforcement on the coping top, and (4) with a reinforcing structure and reinforcement on the coping top. The reinforcement adjacent to the top of the coping and the medial part reduces the stress beneath the loading side of dentures and widely and evenly distributes the stress of the residual alveolar ridge.

Purpose: The aim of this retrospective study was to evaluate the 5-year clinical outcome for ceramic veneered cobalt-chromium (Co-Cr) fixed dental prostheses (FDPs) fitted in a private clinical setting. Materials and Methods: All patients treated consecutively with Co-Cr FDPs from January 2000 to November 2005 were included, and complications were registered. Patient records were examined for details on the restorations and abutment teeth. A total of 149 patients with 201 FDPs, 1,135 units, and 743 abutment teeth were recorded. Results: Of the 149 patients, 122 (82%) were followed for 5 years. Complications occurred in 34 patients (23%) and 38 FDPs (19%). The most frequent were caries (6.7% of patients, 5% of FDPs, 2.2% of abutments) and cement failure (6.7% of patients, 5% of FDPs, 3.1% of abutments). Cohesive ceramic fractures occurred in only 7 FDPs (3.5% of FDPs, 0.7% of units). No adhesive ceramic fractures were recorded. The 5-year cumulative rates for success and survival were 83.8% and 92.8%, respectively. Conclusions: Co-Cr FDPs appear to be a promising prosthodontic treatment modality, presenting low incidence of complications and a high survival rate during the first 5 years of function. However, long-term randomized controlled studies are necessary to confirm these findings.

Purpose: The gradual shift from using implants with turned surfaces to implants with moderately rough surfaces has raised questions regarding the long-term behavior of the latter. The aim of the present retrospective study was to compare clinical and radiographic data of the two implant surfaces using the "same mouth" approach. Materials and Methods: A total of 122 consecutive patients were treated with both turned and TiUnite implants; however, 26 of these patients could not be reached for follow-up and were excluded from the study. The remaining 96 patients received 257 turned and 243 TiUnite Brånemark System implants, not necessarily supporting the same constructions and not necessarily inserted during the same session. Data were collected up to 10 years of function. Results: During the first 6-year period, 18 turned implants and 1 TiUnite implant failed, resulting in implant cumulative survival rates (CSRs) of 93.0% and 99.1% for turned and TiUnite implants, respectively. During the following years, 1 turned and 3 TiUnite implants failed, resulting in CSRs of 90.3% and 96.6% for the two surfaces, respectively, a significant difference. A small but significant difference in mean bone level was seen between turned and TiUnite implants. Conclusion: Implants with turned and TiUnite surfaces showed comparable clinical and radiographic data during the study period. The early implant failure rate, as well as the overall failure rate, were significantly reduced when using TiUnite implants.

This study sought to develop a database in the field of removable prosthodontics by using a participatory action research method. Data collection consisted of a comprehensive literature review, focus-group discussions, and interviews. Applying action research methods ensures consideration of the needs, perspectives, and expertise of academia in the design and implementation of an evidence/ research-based patient record, and academic educators are well placed to conduct such research.

In the mid-nineties, 27 patients received 31 implant-supported crowns in the anterior maxillary region, and 12 to 15 years later, 18 patients (67%) with 22 implants (67%) participated in a retrospective study evaluating implant survival, bone loss, prosthetic complications, patient satisfaction, and patient and professional evaluation of esthetics. One implant was lost because of implant fracture after 10 years. Mean marginal bone loss was 1.53 mm (standard error ± 0.17 mm). In 6 patients, 6 crowns were replaced and 1 repaired. In 3 patients, 3 crowns had minor unrepaired porcelain fractures. Implant survival was 95.5%, and, despite the high frequency of prosthetic complications, patients were generally very satisfied with the long-term treatment outcome.

Purpose: This study aimed to compare the fit of computer-aided design/computerassisted manufacture (CAD/CAM) abutments provided by a single system with proprietary prefabricated abutments on various implant systems. Materials and Methods: Titanium CAD/CAM abutments were compared with prefabricated abutments on five different implant types. The samples were embedded in epoxy resin, sectioned longitudinally, and polished. Scanning electron microscopy was used to measure the gap between the implants and abutments at the connecting flanges and internal features. Independent t tests were used to compare data. Results: A mean difference of 1.86 µm between the gold synOcta and CAD/CAM abutments on the Straumann Standard Plus implant was observed to be statistically significant (P = .002). Less than 0.4 µm of difference was found between the CAD/CAM and prefabricated abutments for the remaining implant types, and statistical significance was not observed. Mean differences of 34.4 µm (gold) and 44.7 µm (titanium) were observed between the CAD/ CAM and prefabricated abutments on the Straumann Standard Plus implants, which were statistically significant (P .001). A mean difference of 15 µm was also observed between the CAD/CAM and prefabricated abutment on the NobelReplace implant, which was statistically significant (P = .026). All other groups had less that 4 µm of difference, and statistical significance was not observed. Conclusion: The CAD/CAM abutments appeared to have a comparable fit with prefabricated abutments for most of the systems evaluated. Design differences between the abutment connections for both Straumann implants were observed that affected the fit of internal components of the implant-abutment connections.

The purpose of this study was to evaluate the fracture resistance of computer-aided design/computer-assisted manufacture (CAD/CAM)-fabricated fiber-reinforced composite (FRC) denture retainers. Distal extension dentures incorporating two telescopic retainers and two molar pontics, with or without fiberglass, were fabricated by CAD/CAM or by the conventional polymerization method. The dentures were subjected to a vertical load on the second molar pontic until fracture. Within each manufacturing method, embedment of the FRC increased the mean final fracture load, suggesting the reinforcing effect of fiberglass. The polymerized dentures with FRC showed greater mean final fracture load than the CAD/CAM dentures with FRC.

The aim of this study was to comparatively evaluate the fracture strength of endodontically treated canines restored with glass-fiber posts (GFPs) and either metal-ceramic (MC) or all-ceramic (AC) crowns in the presence or absence of 2 mm of ferrule height. Fifty human maxillary canines were endodontically treated and randomly divided into five groups of 10 specimens each. The first group remained intact (control), while the remainder were restored with GFPs and composite cores with either MC or AC crowns. Each of the AC and MC groups was equally divided between teeth with or without ferrule. Teeth were embedded in acrylic resin and loaded at a 135-degree angle to their long axis until fracture. Fracture strength was not significantly different between ferrule and no ferrule groups (P = .571), but was significantly larger for the MC groups compared with the control and AC groups (P = .009 and P = .024, respectively). A significant effect of the type of restoration was found as teeth restored with MC crowns presented significantly higher fracture strength, independently of ferrule.