The International Journal of Prosthodontics, 06/2013

An upfront disclosure: I regard biennial International College of Prosthodontists (ICP) meetings as offering exciting and innovative scope for advancing global scholarship in prosthodontics. They are not burdened with national political agendas; personal ones are virtually nonexistent; and each meeting's organizing committee provides the desirable milieu of memorable venue and social events. The result is a renewed commitment to camaraderie of intellectual rigor as reflected in the choice and synthesis of presenters and topics on what is relevant in the discipline. Franco Bassi's local organization of the recent Turin meeting was a particularly memorable one; and Co-Presidents Martin Gross and Yoshi Maeda provided an eclectic selection of learning material for the record number of attendees. Their selection of a very high standard of the traditional cafeteria selection of clinical topics was bookended by introductory and concluding half-day sessions that provided particular resonance for making informed clinical decisions. They ranged from examples of methodological rules that conform to standards of scientific reporting to scrupulous and provocative ones that cast doubt on the presumed clinical relevance of so many prevailing assumptions and beliefs that define evidence-based dentistry. This journal has frequently suggested that alternative frameworks for planning and reporting clinical research need to be studied on an ongoing basis if we are to avoid the "methodological fetishism and quantitative biases" that risk creating conceptual culde- sacs.1 It may now be argued that several clinical meetings continue to risk dumbing down the primacy of scrupulously observed and documented clinical experiences. Hence, the recurrent questions: Is evidence- based support for making the best informed clinical decisions so good that we actually risk experiencing an erosion of dentistry's core values of prudence, compassion, and serious consideration of patient-mediated concerns? Is it clinically tenable to leave the definition of practices associated with new technologies and associated interpretations of new disease processes (eg, so-called peri-implantitis) in the hands of naïve rationalists? Given this context, it is worth recalling that the single biggest catalyst for global change in dental treatment in the past three decades was Branemark's original report on the osseointegration technique2- certainly not your classical randomized controlled trail report. Nonetheless, his work catalyzed extraordinary and novel options for managing partial and complete edentulism, let alone patients with orofacial deficits. The results of such ICP sessions encourage an intellectual free-fire zone with nothing off limits for discussion; and above all without any risk of breakdown in international comity. Clinical scientific meetings of this kind augur well for desirable, indeed necessary, ongoing searches for new and alternative paradigms. Even better informed clinical decisions are bound to result from this sort of collective debate.

Purpose: To evaluate the outcome and special characteristics of immediate implant rehabilitation using the All-on-Four treatment concept in completely or potentially completely edentulous Chinese patients. Materials and Methods: A convenience sample consisted of 69 consecutive patients (37 men, 32 women; mean age: 56.7 years) treated with immediate implant placement and full-arch prosthodontic provisional prostheses between April 2008 and December 2011. Of 344 implants (192 mandibular, 152 maxillary), 240 implants were placed in fresh extraction sites. The remaining 104 implants were placed in healed sites. Implants were immediately loaded with a fixed full-arch provisional prosthesis. Implant survival rate, marginal bone loss, abutment selection, complications, and subjective patient responses were recorded during follow-up. Results: Implant survival rate was 96.2% at 33.7 months of mean follow-up (range: 12 to 56 months). A statistically significantly higher implant survival rate was found in the mandible (99.0% vs 92.8%) (P < .05). No significant difference existed between survival rates for implants placed in postextraction sites and healed sites (P > .05). Peri-implant marginal bone loss around upright implants and tilted implants was 0.7 ± 0.2 mm and 0.8 ± 0.4 mm, respectively. All patients reported satisfactory treatment outcomes. Conclusions: The modified All-on-Four treatment concept provides predictably favorable outcomes in completely or potentially completely edentulous patients and is well suited to the sociodemographic needs of Chinese patients. Exploratory use of a surgical guide was limited because of mouth opening, and more angulated abutments were needed in anterior upright implants of the maxilla.

Purpose: To study the medium- to long-term outcome of implant treatment in patients with neurologic disabilities. Materials and Methods: Twenty-seven patients with different disabilities and in need of prosthodontic treatment were treated with various implant-supported prostheses. Altogether, 88 threaded titanium implants were placed. General anesthesia was used in 21 patients and local anesthesia in 6 patients. Patients were recalled every 3 months by a dental hygienist and annually by a prosthodontist. Results: Five of the original 27 patients died during the 5- to 10-year follow-up period (mean, 7.2 years), but the remaining 22 patients with 70 implants could be clinically examined at the final follow-up. Twelve implants (14%) were lost, 3 before loading and 9 after insertion of the implant-supported fixed prostheses. The cumulative survival rate for placed implants was 85.8% after 10 years. Perimucositis was diagnosed in 10 patients and for 14 of the 70 implants. Three of the 15 patients with measurable radiographs and 4 implants were diagnosed with peri-implantitis. Several prosthodontic complications occurred, from minor and easily correctable to severe and requiring retreatment. Conclusions: Patients with different neurologic disabilities present more problems during implant treatment and maintenance compared with healthy patients. Nevertheless, it was possible to carry out treatment, and outcomes were relatively favorable. The results indicate that implant treatment can be a valid option in oral rehabilitation of patients with neurologic disabilities.

Purpose: The objective of this study was to determine the prevalence of xerostomia among patients attending a dental clinic for provision of dentures and to investigate the oral cleanliness in those patients. Materials and Methods: Denture-wearing patients who reported dry mouth completed a questionnaire related to xerostomia. Dryness of the mouth was determined by clinical observation. Dental and denture cleanliness was determined using the Modified Debris Index. Results: One hundred twenty patients had xerostomia. Oral cleanliness was generally poor. Conclusion: There was a high prevalence of xerostomia in the patient population. A high proportion of subjects had poor oral cleanliness.

Purpose: To examine whether an ambulatory bruxism recording system, including a biologic monitor, that measures sleep variables and sympatho-vagal balance can specifically identify sleep bruxism (SB) at home. Materials and Methods: Twentysix volunteers, including 16 SB subjects, were recruited. Each participant recorded his or her electromyogram (EMG), sympatho-vagal balance, and sound level for 3 consecutive nights using an audio-video recorder to identify SB. Data of sleep variables were compared among the 3 experimental nights. The episodes were classified into SB episodes with and without grinding and non-SB episodes. EMG patterns, amplitude, sympatho-vagal balance, and sound level of all episodes were analyzed so as to determine the appropriate thresholds to detect SB episodes and grinding sound. Then, all episodes without video-recording data were classified into SB and non-SB episodes by using the appropriate thresholds, and the sensitivity and specificity to detect SB episodes were calculated. Results: With regard to sleep variables, there were no significant differences except for sleep latency between the first and second nights. The appropriate EMG pattern and thresholds of amplitude, sympatho-vagal balance, and sound level were phasic or mixed EMG pattern, 20% of maximum voluntary contraction, mean + 1 SD, and mean + 2 SDs, respectively. The sensitivity and specificity to detect SB episodes were 88.4% and 74.2%, respectively. Conclusion: The results suggest that this system enables the detection of SB episodes at home with considerably high accuracy and little interference with sleep.

Purpose: The aim of this trial was to evaluate telescopic-retained prostheses on teeth and implants. Materials and Methods: Ten patients with a mean of 2.8 teeth received strategic implants to achieve triangular/quadrangular support. Survival and complication rates were estimated for telescopic abutments and prostheses. Results: After a mean observation period of > 2 years, no abutment was lost and all prostheses were in function. Complication rates were low, and maintenance services were limited to minor interventions. Conclusions: Combined tooth-implant-retained telescopic prostheses improve prosthetic support and offer successful function over a midterm period in patients with a severely reduced dentition.

This study aimed to clinically evaluate the disinfection efficacy of chlorine dioxide (ClO2) for used dental instruments. An imprint culture technique demonstrated that ultrasonic cleaning of intraorally applied dental mirrors in 0.02% ClO2 for 10 minutes resulted in compete removal of microorganisms for 10 subjects. Hepatitis C virus (HCV) RNA was detected by real-time polymerase chain reaction on periodontal curettes after subgingival scaling in four HCV-infected patients and was completely removed by the same treatment procedure. Therefore, the combination of ultrasonic cleaning with ClO2 may provide an alternative to toxic disinfectants, such as glutaraldehyde and sodium hypochlorite, for disinfecting dental instruments.

The amount of tooth structure that is removed as a consequence of tooth preparation has rarely been quantified. The aim of this study was to quantify the volume of reduction of tooth structure associated with different commonly used preparation designs. Eighty extracted teeth were divided into eight groups according to the type of preparation design and tooth type. Each specimen underwent pre- and postpreparation scanning using microcomputed tomography. The volume of the resultant tooth structure removed was analyzed. Significant differences in the amount of tooth structure removal were noted between types of coverage and types of teeth.

Purpose: To measure the vertical occlusal forces transmitted through crowns made of different restorative materials onto simulated peri-implant bone. Materials and Methods: The study was conducted using a masticatory robot that is able to reproduce the mandibular movements and forces exerted during mastication. During robot mastication, the forces transmitted onto the simulated peri-implant bone were recorded using nine different restorative materials for the simulated single crown: zirconia, two glass-ceramics, a gold alloy, three composite resins, and two acrylic resins. Three identical sample crowns for each material were used. Each crown was placed under 100 masticatory cycles, occluding with the flat upper surface of the robot to evaluate the vertical forces transmitted. Two-way analysis of variance was used. Alpha was set at .05. Results: The statistical evaluation of the force peaks recorded on the vertical z-axis showed mean values of 641.8 N for zirconia; 484.5 N and 344.5 N, respectively, for the two glass-ceramics; 344.8 N for gold alloy; 293.6 N, 236 N, and 187.4 N, respectively, for the three composite resins; and 39.3 N and 28.3 N, respectively, for the two acrylic resins. Significant differences were found between materials (P < .0001), except for the comparison between gold alloy and one of the glass-ceramics. Conclusion: Composite and above all acrylic resin crowns were more able to absorb shock from occlusal forces than crowns made of zirconia, ceramic material, or gold alloy.

Purpose: This retrospective study assessed treatment outcomes and patient satisfaction of irradiated head and neck cancer patients treated with mandibular implant overdentures (IODs) or conventional dentures (CDs). Materials and Methods: Fiftyone irradiated head and neck cancer patients, out of a total of 158 patients included, completed the standardized questionnaire and underwent a clinical assessment. Nineteen patients were treated with removable CDs and 32 patients received IODs between January 2006 and January 2011. The mean follow-up of patients was 5.75 years (range: 1 to 23 years). Results: A total of 45 (88.3%) mandibular dentures were in function at the time of assessment. The overall denture satisfaction was 7.3 (range: 1 to 10, SD: 2.14). Patients being treated with adjuvant concepts, including surgical tumor ablation, scored worse than patients after radiation therapy alone. Edentulous patients seem to benefit from implants, especially with respect to prosthesis retention. Men take more benefit from IODs compared with women. Conclusions: The results are comparable to other studies of head and neck cancer patients and also of healthy individuals. Surgical interventions in adjuvant therapy concepts lead to reduced denture satisfaction. The concept of prosthetic rehabilitation as part of oncologic treatment can be judged as successful.

This study evaluated how the contact height between the magnetic attachment and denture base influences stability and bending strain. An implant modified with strain gauges and a magnetic attachment mounted in an acrylic resin block were used to characterize systems with varying degrees or heights of contact with the abutment. Bending strain under lateral loading increased significantly as the contact height decreased. In the no contact and resilient contact groups, magnetic assemblies separated at reduced bending strain in all loading conditions. The contact height of the magnetic attachment influenced the stability and the amount of bending strain on the implant.

Purpose: To evaluate telescopic crown (TC), bar, and locator attachments used in removable four implant-supported overdentures for patients with edentulous maxillae. Materials and Methods: A total of 30 maxillary edentulous patients were enrolled in a 3-year prospective study. Ten patients (group A) were treated with overdentures supported by TCs, 10 patients (group B) with overdentures supported by bar attachments, and 10 patients (group C) with overdentures supported by locator attachments. A total of 120 implants were used to restore oral function. During the 3-year follow-up period, implant survival and success rates, biologic and mechanical complications, prosthodontic maintenance efforts, and patient satisfaction were evaluated. Results: All 30 patients were available for the 3-year follow-up and exhibited 100% implant survival and success rates. Peri-implant marginal bone resorption was not statistically significant for the three groups. There were lower plaque, bleeding, gingiva, and calculus indices in group C compared with groups A and B. The number of prosthodontic maintenance visits revealed eight complications in the TC group, seven complications in the bar group, and four complications in the locator group. However, there were no differences in the clinical effects of the overdentures in the three groups. Conclusion: Within the limits of this prospective study, it was concluded that the locator system produced superior clinical results compared with the TC and bar attachments in terms of peri-implant hygiene parameters, the frequency of prosthodontic maintenance measures, cost, and ease of denture preparation. However, longer-term prospective studies are required to confirm these results.

Occlusal support may be an important factor affecting nutritional support after major surgery. This report presents a patient who gained body weight after receiving a new prosthesis. The patient was an 82-year-old man with thoracic esophageal carcinoma. He did not have occlusal support because of multiple caries lesions. His body weight slowly increased after surgery, but almost stopped in the period of 54 to 68 days after surgery. After treatment with dentures (day 72 postsurgery), body weight gain was observed again, although his medical treatment had not changed. An appropriate prosthesis could contribute to perioperative nutrition support and may lead to earlier recovery after surgery.

Purpose: A die stone jig was evaluated as to its ability to clinically verify the position of the abutment replicas on the master cast. Materials and Methods: A clinical evaluation was made on 58 edentulous arches necessitating rehabilitation with fixed partial dentures. Any broken jigs detected were replaced with a new set of jigs and clinically retested. Data were statistically confirmed. Results: Fifty-five percent of the 58 jigs broke, with a 95% confidence interval (CI) of 42.5 to 67.3; after replacement, there were no breakages (95% CI: 0 to 6.2). Conclusions: The jig detected misfits in clinical trials, according to the parameters defined in the literature.