The International Journal of Prosthodontics, 05/2013

My recurrent July anxiety state is elicited by a flood of IJP submissions-authorial knee-jerk responses to our announcement that we close shop for the month of August. Preliminary reads of these preholiday submissions are not followed by immediate reviewing assignments. They are instead postponed until September to avoid intruding into the concluding phase of our reviewers' "exhausted loyalist" academic year. I concentrate instead on a preholiday stock-taking of my year's scholarly engagements. This may sound like overreach for one who actually retired from academic career timetables. But I continue to regard selected meeting attendances and organizational activities as relevant engagement for my editorial mandate; and the past 12 months were particularly enriching ones. The two 2012 IJP/Karlsruhe Workshops (Baden- Baden, Germany, in June and Beijing, China, in December) were gratifying examples of an international faculty's extraordinary cooperation and commitment, International College of Prosthodontists (ICP) endorsement, and invaluable support from Nobel Biocare and the Chinese Ministry of Education, respectively. These initiatives provide a unique educational clinical vision for Young Prosthodontic Educators and will undoubtedly continue to grow in stature and recognition. There are, inarguably, few comparable global educational initiatives that prioritize prudent patient-mediated needs as an integral part of managing the prosthodontic patient. October 2012 and June 2013 meetings in Toronto and New York City, respectively, offered the privilege of chairing both scientific committees with outstanding colleagues to rely on. We synergized with Nobel Biocare's exceptional international meeting organizational teams and largely adopted traditional lecture formats to focus on patient-mediated concerns in the context of the different therapeutic journeys that are undertaken in implant therapy. The huge audiences in attendance (over 750 in Toronto and 2,000 in New York City) were impressive endorsements of implant prosthodontics' global success trajectory since the original Toronto Conference in 1982, while reflecting somewhat different clinical agendas from the IJP/ Karlsruhe Workshop ones. In fact, a relative newcomer to the field might have come away from the clinical meetings with the conviction that traditional prosthodontic therapy is, indeed, passé. The narratives from both pairs of significantly different formats-equally scientifically robust and clinically relevant-increased my ambivalence about my discipline's stewardship of patient care. It is perhaps best summed up by posing the question: Has the template of traditional prosthodontic interventions been completely eclipsed by the advent of implant therapy? I will try to address this rather compelling question in future editorials via both personal and invited submissions, while initiating the necessary debate with preliminary thoughts about the edentulous predicament. The dental profession's overriding conceit that any form of tooth loss constitutes a disease that demands an intervention, may still be readily challenged in the context of our understanding the causes of teeth loss and its significance rather than in blanket justifications for routine restoration of function and esthetics. Nonetheless, the edentulous state is justifiably regarded as a serious personal predicament that has plagued humanity for hundreds of years and has been ascribed a range of adverse sociologic and health consequences. Since documented experience and research demonstrate impressive progress in materials sciences and clinical techniques, together with an emergent and profound understanding of masticatory function, the profession and surrogate practitioners have already provided a complete denture service that has, until recently, led the body replacement parts effort in the necessary pursuit of restored function and esthetics. And yet, predictably successful management of complete edentulism has never been claimed as a certainty given the harsh fact that time destroys rather than heals complete dentures' vulnerable supporting tissues, and that patients' responses to wearing dentures are often unpredictable. Brånemark's introduction of osseointegration dramatically influenced this concern; it ushered in an exciting scope for raising the management of edentulism to a new level of predictable quality. His work catalyzed new and enriched synergies between surgical and prosthodontic expertise while provoking new concerns regarding stewardship for patientmediated responsibilities and concerns. I readily acknowledge that the proliferation of surgical skills and techniques that are frequently accompanied (sometimes even driven) by professional and commercial ingenuity now offer dramatically improved treatment choices for edentulous patients. Yet, these approaches also resonate as an exercise in ambiguity for those of us instant converts to using one or more implants in the anterior zone of the edentulous mandible to address the majority of patients' denturewearing concerns. The risk here is that the old maxim "when all you have is a hammer, everything around looks like a nail" will prevail; and that the knee-jerk response of a freshly hammered surgical prescription will dominate the field of edentulism. And while this may very well prove to be an optimal management narrative for numerous edentulous patients, it is also grossly insensitive to suggest that complete dentures are no longer the answer for numerous patients who live in prosperous countries, let alone the many more that are not so lucky. There is, of course, a far larger issue here. Current professional pride in new treatment options still needs to be reconciled with the sort of long-term outcome results that engaged so many of us back in 1982 when the osseointegration genie first came out of the bottle. Our prosthodontic stewardship of the edentulous population cannot lose sight of the dramatic increase in life expectancy along with shifts in societal pyramids. Multimorbidity and treatment uncertainties in the elderly cohort are serious emerging concerns that cannot be ignored, irrespective of whether patients wear complete dentures or implant-supported alternatives. Moreover, the context of a continuum of implant treatment outcome management needs also demands cognizance of well-articulated and debated patient-mediated concerns. Ours remains the obligation to ensure that the brilliance of applied osseointegration does not succumb to a formulaic approach. And, above all, that it does not risk becoming an unavoidable and unnecessary burden for an aging edentulous population as well as an insurmountable challenge for our discipline.

The functional outcomes related to treating patients afflicted with tooth loss are an important hallmark in substantiating prosthodontic intervention. The Oral Rehabilitation Outcomes Network (ORONet) conducted two international workshops to develop a core set of outcome measures, including a functional domain. The process followed the general format used in the Outcome Measures in Rheumatology (OMERACT) workshops to develop consensus for clinical outcome measures in arthritis research, which included: developing a comprehensive list of potential outcomes in the literature; submitting them to a filter for validity, clinical discrimination, and feasibility; and ranking those measures meeting all the filter criteria for relative value. The search was conducted to include functional assessments of speech, swallowing, mastication, nutrition, sensation, and motor function as they relate to dental implant therapies. This literature review surveyed 173 papers that produced some result of these descriptors in the functional domain. Of these, 67 papers reported on functional assessments and further defined objective and subjective outcomes. Many of these results were patient-perceived improvements in function, while others were objective assessments based on established methodologies and instruments. Objective evaluations of masticatory function and speech may meet criteria for validity and discriminability for selected interventions, but are generally not feasible for routine use in clinical care settings. The current recommendation is to employ a well-validated survey instrument that covers mastication and speech, such as the Oral Health Impact Profile (OHIP-14, short form), recognizing that patient perceptions of function may differ from objective ability.

The purpose of this study was to compare the strain of complete dentures with and without full palatal coverage and to determine the effect of reinforcement. Three types of maxillary complete dentures (with palate, without palate, and without palate but with reinforcement) were fabricated, and reinforcements were made from a cobaltchromium alloy. Strain gauges were attached to the polished surface, and a vertical load was applied in the region of the first premolar and first molar. The strains were statistically compared. The greatest strain occurred on the anterior palatal surface and was tensile in the denture with palatal coverage and compressive in the denture without palatal coverage. Significantly less strain occurred in dentures with reinforcement than without reinforcement.

Purpose: The amounts of calcium (Ca), magnesium (Mg), zinc (Zn), and copper (Cu) in enamel may be crucial for maintaining its integrity and to attenuate potential environmental effects on teeth. The aim of this study was to examine whether the mineral composition of enamel could influence tooth wear. Materials and Methods: A total of 50 patients with severe tooth wear were compared with 20 healthy volunteers. Tooth wear was assessed using clinical examination according to the protocol of Smith and Knight. Subsequently, the maxillary central incisors of each subject were subjected to acid biopsies to assess the mineral composition in the enamel. Atomic absorption spectroscopy with an air/acetylene flame was used to analyze for Ca, Zn, and Mg. Graphite furnace atomic absorption spectroscopy was used to analyze for Cu. Results: The concentrations of Ca and Mg in tooth enamel were comparable in the study and control groups. Zn enamel content was higher in patients with tooth wear, and Cu enamel content was lower in these patients compared with the control group. Conclusion: The differing Zn and Cu contents in tooth enamel might offer a reason for excessive tooth wear in these patients. However, the results require further, more detailed study.

Consensus regarding outcomes of the treatment of tooth loss, especially the psychologic outcomes, is needed to guide discovery of best practices and enable a better understanding of patient management for this chronic condition. This paper presents the findings of the ORONet Psychological Working Group for prosthodontics and aims to identify psychologic outcomes with properties deemed critical to meet clinical trial and clinical practice needs for the future. References obtained using a PubMed/Medline search were reviewed for clinical outcomes measures of interest. Clinical outcomes measures were judged relative to the criteria of truth, discrimination, and feasibility. Of the psychologic outcome measures identified in this systematic review, only the OHIP-14 was thought to be suitable for use in general practice and multi-institutional outcome registries and clinical trials. Development of clinically useful psychologic outcomes for future use could benefit from developmental methods and tools outlined in the patient-related outcomes field of clinical care.

Purpose: The aim of this retrospective cohort study was to gather the outcomes of zirconia single crowns made by 16 members of the Italian Academy of Prosthetic Dentistry (AIOP) over a time period of up to 5 years. Materials and Methods: A total of 398 patients treated in private practices with 1,132 zirconia-based single-crown restorations made on natural teeth from January 2005 to July 2010 were included. Three hundred forty-three anterior restorations (30.3%) and 789 posterior crowns (69.7%) were made with 16 types of zirconia, using primarily chamfer or knife-edge tooth preparation, and examined according to the esthetic, functional, and biologic criteria. To evaluate the relationship of parafunction with mechanical failure, patients with clenching or bruxism were not excluded from the study group. Results: The cumulative survival rate of all restorations was 98.1%, while the cumulative success rate was 94.3%. Functional criteria had the highest number of failures. The odds ratio (OR) for all restorations was calculated to clarify the relationship between patients who were subject/not subject to parafunctions and technical complications; the OR was 2.60. An association between parafunction and mechanical failure was found in patients with severe parafunction. Conclusions: Porcelain-veneered zirconia single crowns with chamfer and knife-edge preparations showed good clinical results over a period of up to 5 years. Technical complications were few and were limited primarily to patients with parafunction.

Purpose: To retrospectively evaluate the 6-year survival rates and technical/ biologic complication rates of single-retainer glass-ceramic resin-bonded fixed dental prostheses (RBFDPs). Materials and Methods: Forty patients with 49 anterior/posterior glass-ceramic RBFDPs were included. The RBFDPs replaced 11 maxillary/mandibular central incisors, 18 lateral incisors, 18 premolars, and 2 molars. Patients willing to participate were clinically and radiologically examined. The technical outcome was assessed with modified United States Public Health Service criteria. Fracture and/or chipping of the restoration, occlusal wear, marginal adaptation, marginal discoloration, shape, surface texture, and esthetic integration were recorded. Tooth vitality and postoperative sensitivity were tested. The following biologic parameters were assessed at test and control teeth: probing pocket depth, gingival recession, attachment loss, bleeding on probing, furcation involvement, and periodontal mobility. Statistical analysis was performed with exact 95% confidence intervals to relative frequencies and the paired t test. Results: Twenty-eight patients with 35 RBFDPs participated. The mean follow-up of the RBFDPs was 6 years. Twelve patients with 14 RBFDPs were not willing to participate or not available. No catastrophic failures occurred. The 6-year survival rate of the examined RBFDPs was 100%. No debonding was recorded. Chipping of the ceramic was found in 5.7% of the RBFDPs. Biologic outcomes were similar at test and control teeth. Conclusion: Glass-ceramic RBFDPs exhibited promising clinical outcomes in both anterior and posterior regions.

Purpose: To introduce a new three-dimensional (3D) method of evaluating the fit of implant superstructures made using computer-aided design/computer-assisted manufacture (CAD/CAM) technology and conventional casting and to determine which biomaterial would produce optimal fit for the long-term clinical longevity of dental implant restorations. Materials and Methods: Five groups of materials were used to make 50 copings (n = 10) using CAD/CAM technology for titanium, partially sintered zirconia, fully sintered zirconia, and leucite-reinforced glass-ceramic materials and a conventional casting technique for the nickel-chromium group. The vertical marginal gap was measured at 16 equidistant points using a traveling microscope and compared with the 3D spatial gap values obtained by using spiral scan microtomography. Multivariate analysis of variance and Tukey post hoc tests were used for statistical analysis. Results: The vertical marginal gap width ranged from 13.21 to 75.26 μm for the CAD/CAM groups and 64.89 to 115.27 μm for the conventionally casted group. The spatial gap ranged from 0.22 to 0.67 mm3 for CAD/CAM groups and 0.75 to 0.89 mm3 for the conventionally casted group. The highest accuracy of fit was observed in the titanium group, followed by the leucite-reinforced glass-ceramic, partially sintered zirconia, fully sintered zirconia, and nickel-chromium groups. Conclusion: When used in combination with the CAD/CAM technique, titanium produces the most accurate implant superstructure. Spiral scan microtomography can be used to measure the accuracy of fit of dental implant superstructures and restorations as it provides a 3D measurement with less chance of errors compared with conventional methods of measurement.

Purpose: The aim of this study was to evaluate and compare the outcomes of immediately loaded all-ceramic crown restorations supported by implants placed in both mature bone and immediate extraction sockets. Materials and Methods: Forty-three tapered, external hex implants were placed immediately after extraction or in healed bone in a convenience sample of 38 patients from two clinics, with 23 implants immediately placed after tooth extraction and 20 placed in mature bone. Thirty implants were located in the maxilla and 13 in the mandible. Each surgical implant placement was followed by the fabrication of a screw-retained all-ceramic crown (zirconia-toughened alumina cylinder and layered with porcelain) that was then put into immediate function. Each patient was recalled annually for clinical and radiographic assessments. Results: All implants were loaded immediately and all functioned successfully following a mean follow-up of 26 months. Significantly more bone loss was recorded around delayed implants compared with immediately placed ones. Smoking, platform switching, and jaw location did not influence peri-implant bone loss. Porcelain chipping was noted in the case of two crowns. Conclusion: The short-term outcome of prefabricated ceramic cylinders used to support a single screw-retained crown was regarded as successful. Immediate implant placement did not appear to increase the risk for implant failure and was accompanied by reduced peri-implant bone loss.

Purpose: A systematic literature review was conducted to identify the types of economic measures currently used in implant prosthodontics and determine the degree to which cost of care is considered in the context of any positive outcome of the care provided. Materials and Methods: A literature search was conducted using the following set of terms plus some additional hand searching: "dental implants" (Mesh) AND ("cost") OR "maintenance" OR "healthcare policy" OR "access to care" OR "third party" OR "economic") AND (("1995/01/01"[PDat]:'2009/12/31"[PDat]) AND (Humans[Mesh]) AND (English[lang])). Results: After a review of the 466 titles and abstracts identified by the search, 18 articles were accepted for further consideration, as some attempt at economic outcome measures was made. An additional four articles were identified by hand searching. The 22 accepted articles were grouped into four basic categories: (1) measure of costs of treatment (direct, indirect, and maintenance costs), (2) cost-effectiveness mathematical modeling applied to simulate the lifetime paths and cost of treatment, (3) cost-effectiveness analysis/costminimization, and (4) willingness-to-pay, willingness-to-accept. Attempts at determining the costs of treatment varied widely. When the OMERACT filters were applied to the various measures it was felt that discrimination and/or feasibility was a problem for most of the current economic outcome measures. Conclusions: Measures of cost-benefit, cost-effectiveness, and cost-utility are currently the gold standard; however, feasibility of such analyses is an issue. Collaboration with health economists to guide future research is highly recommended.

Purpose: The aim of this study was to evaluate the influence of time-course changes and various types of removable dentures on the oral levels of Candida species. Materials and Methods: In this prospective clinical trial, 72 subjects were divided into three groups according to the type of denture replaced: Kennedy Class I or II removable partial dentures (RPDs), Kennedy Class III or IV RPDs, and complete dentures. Whole saliva and biofilm samples from the palate, tongue, dentures, and inner surface of the cheek were obtained and evaluated for Candida diversity before the delivery of the new prostheses (baseline) and at 1, 6, and 12 months postdelivery. The results were analyzed using a three-way analysis of variance, followed by a post-hoc Student-Newman-Keuls test. Results: Candida levels decreased after the insertion of the new dentures; however, after 6 months, Candida levels were similar to baseline, and complete denture wearers presented higher Candida counts than RPD wearers. Conclusion: The type of denture does not seem to be a decisive factor in Candida levels. After 6 months, Candida colonization was well established in all types of removable prostheses. Denture replacement alone did not guarantee a decrease in Candida levels for more than 6 months.

Purpose: A study was conducted to compare the accuracy and time consumption of shade matching tasks performed by students, clinicians, and dental technicians. Materials and Methods: A total of 126 participants were asked to pair shade tabs and to choose the best shade match for three natural teeth using the Chromascop shade guide. Time consumption was recorded. The frequency of correct answers and time consumption results were compared across occupational groups and by levels of clinical experience. Results: No significant difference was found between occupational groups in shade tab pairing or natural tooth color matching. Experience did not affect the shade tab pairing, but experienced participants were better in natural tooth color matching. Clinicians performed the shade tab matching task faster than preclinical and clinical students, while technicians were faster than preclinical students. In the natural tooth color matching task, clinicians and technicians were faster than students. Regarding experience, novice observers were slower than experienced individuals. A significant negative correlation was observed between time consumption for visual shade matching and the frequency of correct matches for both shade tabs and natural teeth. Conclusion: The level of professional experience improved color matching of natural teeth. Overall, clinicians and dental technicians performed faster than students, while lower time consumption for shade matching was associated with better scores.

Purpose: This trial aimed to compare a new technique for defining and transferring the esthetic arrangement to the laboratory with the traditional method. Materials and Methods: One hundred twenty-three consecutive edentulous patients were randomly assigned to a case or control group. The case group received arrangement using adhesive paper teeth. The control group received traditional standard care selection and arrangement of anterior teeth. Measured outcomes were the time needed for arrangement and adjustments, patient satisfaction, and number of adjustments at the trial session. Results: Satisfaction and number of adjustments needed were not statistically different in the two groups. The time needed for arranging teeth was statistically less in the case group. Conclusion: The technique reduces the time necessary for the esthetic arrangement while maintaining comparable quality of the trial and definitive denture.