The International Journal of Prosthodontics, 01/2016

Purpose: Published literature on mandibular movements is extensive, but it lacks scientific robustness and is understandably controversial. This preliminary study recorded and assessed characteristic forms and condylar path inclination patterns during mandibular protrusion and opening in completely edentulous subjects. These features facilitate the setting of condylar guidance records on articulators. Materials and Methods: A convenience study sample of 60 asymptomatic edentulous patients (aged 58 to 74 years) was provided with new complete dentures. After localizing hinge axis movement, sagittal condylar paths were recorded and analyzed with an electronic axiograph (AXIOCOMP, SAM). Results: Protrusion and opening movement patterns showed completely different characteristics. During protrusive movement, condylar paths showed a sinusoidal pattern (51%), and condylar inclination was low at 1 mm (32.2 degrees) and 2 mm (40.4 degrees). Conversely, during the opening movement, the most frequent pattern found was the classical convex form (57%). Inclinations were higher: 50.8 degrees at 1 mm and 50.7 degrees at 2 mm. Conclusions: Completely edentulous subjects present radically different sagittal condylar paths when compared with dentate patients. These differences result from alterations in disc-condyle relationships and morphologic changes in bone structure. No link was observed between condylar paths recorded in protrusion and opening movements. Consequently, condylar guidance for articulators should be set using recordings from protrusive movements.

Purpose: The aim of this study was to investigate strain on implants used for adjunctive support of distal extension removable partial dentures. Materials and Methods: An implant with strain gauges was used for testing purposes in two positions, parallel and inclined. Three loading scenarios-loading apparatus (LA), artificial teeth via cotton roll (CR), and artificial teeth (UT)-were studied and strains compared via the Kruskal-Wallis test (P = .05). Results: Strain under CR was significantly larger than UT in parallel (P .05). However, the opposite was observed in inclined. Conclusions: Strain in parallel was smallest for UT, whereas in inclined it was largest for CR.

Purpose: Articles reporting survival outcomes (time-to-event outcomes) in patients over time are challenging to identify in the literature. Research shows the words authors use to describe their dental survival analyses vary, and that allocation of medical subject headings by MEDLINE indexers is inconsistent. Together, this undermines accurate article identification. The present study aims to develop and validate a search strategy to identify dental survival analyses indexed in MEDLINE (Ovid). Materials and Methods: A gold standard cohort of articles was identified to derive the search terms, and an independent gold standard cohort of articles was identified to test and validate the proposed search strategies. The first cohort included all 6,955 articles published in the 50 dental journals with the highest impact factors in 2008, of which 95 articles were dental survival articles. The second cohort included all 6,514 articles published in the 50 dental journals with the highest impact factors for 2012, of which 148 were dental survival articles. Each cohort was identified by a systematic hand search. Performance parameters of sensitivity, precision, and number needed to read (NNR) for the search strategies were calculated. Results: Sensitive, precise, and optimized search strategies were developed and validated. The performances of the search strategy maximizing sensitivity were 92% sensitivity, 14% precision, and 7.11 NNR; the performances of the strategy maximizing precision were 93% precision, 10% sensitivity, and 1.07 NNR; and the performances of the strategy optimizing the balance between sensitivity and precision were 83% sensitivity, 24% precision, and 4.13 NNR. The methods used to identify search terms were objective, not subjective. The search strategies were validated in an independent group of articles that included different journals and different publication years. Conclusions: Across the three search strategies, dental survival articles can be identified with sensitivity up to 92%, precision up to 93%, and NNR of less than two articles to identify relevant records. This research has highlighted the impact that variation in reporting and indexing has on article identification and has improved researchers' ability to identify dental survival articles.

Purpose: The aim of this study was to evaluate the oral health-related quality of life (OHRQoL) of patients treated with three different types of mandibular implant overdentures (IOD) after at least 3 years in function. Materials and Methods: A total of 122 patients treated with mini implant (50), locator (56), or bar (16) mandibular IODs participated. Modified plaque (PI) and gingival (GI) indices were also assessed. Results: Older patients and patients with mini mandibular IODs were the most satisfied with their OHRQoL. The bar overdenture presented the worst PI and GI results. Conclusion: The mini mandibular overdenture patients were assessed with a better OHRQoL than those with bar and locator IODs.

Purpose: The aim of this study was to evaluate the long-term clinical performance of and patient satisfaction with implant-supported all-ceramic fixed dental prostheses (FDPs) and to compare two different all-ceramic systems, Denzir (DZ) and In-Ceram Zirconia (InZ). Materials and Methods: A total of 18 patients received 25 partial FDPs; 13 DZ, and 12 InZ. Results: Of these patients, 17 attended the 10-year follow-up. None of the restorations had fractured. Fractures of the veneering porcelain were observed in nine patients; two from the InZ group and seven from the DZ group. All FDPs were in use, and all patients were fully satisfied with the treatment. Conclusion: Results from this long-term follow-up suggest that implant-supported all-ceramic FDPs are an acceptable treatment alternative.

Communication between the clinician and the technician has been an ongoing problem in dentistry. To improve the issue, a dental software application has been developed-the Virtual Facebow App. It is an alternative to the traditional analog facebow, used to orient the maxillary cast in mounting. Comparison data of the two methods indicated that the digitized virtual facebow provided increased efficiency in mounting, increased accuracy in occlusion, and lower cost. Occlusal accuracy, lab time, and total time were statistically significant (P .05). The virtual facebow provides a novel alternative for cast mounting and another tool for clinician-technician communication.

Purpose: The aim of this study was to perform a systematic review and meta-analysis based on clinical trials that evaluated the main outcomes of glass-ceramic and feldspathic porcelain laminate veneers. Materials and Methods: A systematic search was carried out in Cochrane and PubMed databases. From the selected studies, the survival rates for porcelain and glassceramic veneers were extracted, as were complication rates of clinical outcomes: debonding, fracture/chipping, secondary caries, endodontic problems, severe marginal discoloration, and influence of incisal coverage and enamel/dentin preparation. The Cochran Q test and the I2 statistic were used to evaluate heterogeneity. Results: Out of the 899 articles initially identified, 13 were included for analysis. Metaregression analysis showed that the types of ceramics and follow-up periods had no influence on failure rate. The estimated overall cumulative survival rate was 89% (95% CI: 84% to 94%) in a median follow-up period of 9 years. The estimated survival for glass-ceramic was 94% (95% CI: 87% to 100%), and for feldspathic porcelain veneers, 87% (95% CI: 82% to 93%). The meta-analysis showed rates for the following events: debonding: 2% (95% CI: 1% to 4%); fracture/chipping: 4% (95% CI: 3% to 6%); secondary caries: 1% (95% CI: 0% to 3%); severe marginal discoloration: 2% (95% CI: 1% to 10%); endodontic problems: 2% (95% CI: 1% to 3%); and incisal coverage odds ratio: 1.25 (95% CI: 0.33 to 4.73). It was not possible to perform meta-analysis of the influence of enamel/dentin preparation on failure rates. Conclusion: Glass-ceramic and porcelain laminate veneers have high survival rates. Fracture/ chipping was the most frequent complication, providing evidence that ceramic veneers are a safe treatment option that preserve tooth structure.

The aim of this study was to investigate the accuracy and reliability of interpreting occlusal markings made by articulating paper on complete dentures intraorally. Clinical teachers at a training hospital interpreted occlusal markings intended for adjustment. Their scores were compared to a control score to determine accuracy. For reliability determination, the observations were repeated. Only between 20% and 30% of observations were found to be both accurate and reliable. Unless the procedure can be standardized, this technique shouldn't be considered appropriate prosthodontics protocol for balancing the occlusion of complete dentures.

The present clinical case history report describes an interdisciplinary treatment protocol that combines maxillary tumor resection with immediate reconstruction to achieve functional rehabilitation. A fibula flap that received four dental implants and a split-thickness graft epithelial layer was prefabricated for a 31-year-old man. The flap was designed so that it could be adapted to fit in different extents of tumor resection. Resection and immediate reconstruction were successfully performed 6 weeks after flap prefabrication, with the final bar-retained dental prosthesis delivered 4 weeks later.

Purpose: The aim of this study was to validate the Social Appeal Scale (SAS) among the Spanish general population, exploring the underlying dimensions of the construct assessed. Materials and Methods: The SAS test was applied to 555 participants between 16 and 75 years of age. The scale is divided into four dimensions: social competence (SC), intellectual ability (IA), psychologic adjustment (PA), and relationship satisfaction (RS). Results: The SAS (12 items) had a Cronbach alpha of .93, and SC had a Cronbach alpha of .83. For IA it was .85, for PA .87, and for RS .84. Conclusion: Bearing in mind the limitations of the present study, it may be concluded that the Social Appeal Scale is a valid and reliable instrument to assess social perceptions related to changes in tooth color.

Purpose: The aim of this study was to assess the antimicrobial activity of chemical disinfectants on alginate and silicone impression materials. The effect of chemical disinfectants on the dimensional stability of the impression materials was also assessed. Materials and Methods: For the microbiologic assessment, impressions of the maxillary arch were taken from 14 participants, 7 using alginate and 7 using an addition silicone. The impressions were divided into three sections. Each section was subjected to spraying with MD 520 or Minuten or no disinfection (control), respectively. Antimicrobial action of the chemical disinfectants was assessed by measuring microbial counts in trypticase soy agar (TSA) media and expressing the results in colony-forming units/cm2. The surface area of the dental impressions was calculated by scanning a stone cast using computer-aided design/computer-assisted manufacture and analyzing the data using a custom computer program. The dimensional stability of the impression materials after immersion in disinfectants was assessed by measuring the linear displacement of horizontally restrained materials using a traveling microscope. The percent change in length over 3 hours was thus determined. Results: Alginate exhibited a higher microbial count than silicone. MD 520 eliminated all microbes as opposed to Minuten. The bacterial growth after Minuten disinfection was almost twice as much for alginate than for addition silicone impressions. The chemical disinfectants affected the alginate dimensional stability. Minuten reduced the shrinkage sustained by alginate during the first hour of storage. Conclusions: Alginate harbors three times more microorganisms than silicone impression material. Chemical disinfection by glutaraldehyde-based disinfectant was effective in eliminating all microbial forms for both alginate and silicone without modifying the dimensional stability. Alcohol-based disinfectants, however, reduced the alginate shrinkage during the first 90 minutes of setting. The current studies also propose another method to report the surface area based on accurate estimation by 3D image analysis.

Purpose: The aim of this study was to compare the prevalence of tooth loss and prosthetic treatments in dependent, functionally impaired individuals with the general population. Materials and Methods: Data collected from 250 subjects from a register covering dependent and functionally impaired individuals in Sweden were compared with data from matched controls. The collected variables included number of teeth, tooth loss, and prosthetic treatments in the different jaw regions. Results: The study group had a lower mean number of teeth and a higher proportion of complete tooth loss than the control group. Dentures were more common in the study group, and fixed prostheses, including dental implants, were more common in the control group. Gender-based differences related to tooth loss were also apparent. Conclusion: In spite of a well-organized recall system for dental care, differences still existed in tooth loss. The differences were more apparent in older individuals and appeared to be related to general health, functional impairments, and gender. Prosthetic treatment options were unevenly used and only one implant overdenture was found.

Purpose: The aim of this report is to present photogrammetry as a reliable step in the fabrication of a full-arch immediate rehabilitation. Materials and Methods: A 59-yearold man attended the department seeking dental rehabilitation for the sequelae of severe oral health neglect. The mandibular teeth suffered from advanced periodontal disease and the patient wore a maxillary complete denture. An irreversible hydrocolloid impression of the mandibular arch was made, poured in stone, and digitally scanned to create the first stereolithography (STL) file. All teeth with the exception of two retained as landmarks were extracted, and seven implants were placed under local anesthesia and their positions recorded using photogrammetry. Maxillary and mandibular dental arch alginate impressions were made, poured in laboratory stone, and scanned. A provisional restoration was placed 7 hours after surgery using the STL files to determine the best-fit line. Results: Radiographic and clinical follow-up after 1 year showed a favorable evolution of the implants. No screw loosening or other mechanical or biologic complications were observed. Conclusion: The case history using the described system suggests certain advantages over conventional techniques. More research is needed to assess the possible benefits associated with photogrammetry when making implant-supported restorations.

This article presents three cases of single labially tilted implants restored with screw-retained single crowns. Individualized abutments with an angled screw channel were used to avoid an unesthetic vestibular access channel. This individualized abutment allows the dentist and dental technician to use the screw-retained restorations where a cemented reconstruction would otherwise have been needed.

Purpose: The clinical success and longevity of endosseous implants, after their prosthetic finalization, mainly depends on mechanical factors. Excessive mechanical stress has been shown to cause initial bone loss around implants in the presence of a rigid implant-prosthetic connection. The implant abutments are manufactured with high elastic modulus materials such as titanium, steel, precious alloys, or esthetic ceramics. These materials do not absorb any type of shock from the chewing loads or ensure protection of the bone-implant interface, especially when the esthetic restorative material is ceramic rather than composite resin. Materials and Methods: The mechanical resistance to cyclical load was evaluated in a tooth-colored fiber-reinforced abutment prototype (TCFRA) and compared to that of a similarly shaped titanium abutment (TA). Eight TCFRAs and eight TAs were adhesively cemented on as many titanium implants. The swinging the two types of abutments showed during the application of sinusoidal load was also analyzed. Results: In the TA group, fracture and deformation occurred in 12.5% of samples, while debonding occurred in 62.5%. In the TCFRA group, only debonding was present, in 37.5% of samples. In comparison to the TAs, the TCFRAs exhibited greater swinging during the application of sinusoidal load. In the TA group extrusion prevailed, whereas in the TCFRA group intrusion was more frequent. Conclusion: TCFRA demonstrated a greater elasticity than did TAs to the flexural load, absorbing part of the transversal load applied on the fixture during the chewing function and thus reducing the stress on the bone-implant interface.

Purpose: The aim of this study was to evaluate and compare the retention strength of three cements commonly used in implant-supported prostheses before and after compressive cyclic loading. Materials and Methods: The working model consisted of five solid abutments, 7 mm in height and with a 6-degree taper, screw retained to five implant analogs secured in a rectangular block of self-curing acrylic. On the abutments, 30 metal Cr-Ni alloy copings were cemented using three luting agents: glass ionomer, resin urethane-based, and compomer cement (n = 10). Two tensile tests were conducted with a universal testing machine, before and after 100,000 cycles of 100 N and 0.72 Hz compressive cyclic loading in a humid environment. Results: Before applying the compressive load, the retention strength of the resin urethane-based cement was slightly higher than that of the compomer cement and 75% greater than the glass-ionomer cement. After compressive loading, the resin urethanebased cement showed the highest percentage of loss of retention (64.45%, compared with 50% for glass-ionomer and compomer cement). However, the glass-ionomer cement showed the lowest mean retentive strength with 50.35 N as opposed to 75.12 N for the compomer cement and 71.25 N for the resin urethane-based. Conclusions: Compressive cyclic loading significantly influences the retention strength of the luting agents tested. All three cements may favor the retrievability of the crowns.

Purpose: The main goal of this in-vitro study was to evaluate whether tensile strength and retrievability of cemented implant-retained crowns correlate when using artificial aging. Materials and Methods: A total of 128 crowns were fabricated from a cobalt-chromium alloy for 128 tapered titanium abutments (6 degrees taper, 4.3 mm diameter, 4 mm length, Camlog). The crowns were cemented with glass-ionomer (Ketac Cem, 3M) or resin cements (Multilink Implant, Telio CS Cem [Ivoclar Vivadent], Retrieve [Parkell]). Multilink Implant was used without priming. The experimental groups were subjected to either 37,500 thermal cycles between 5°C and 55°C, 1,200,000 chewing cycles, or a combination of both. Control groups were stored for 10 days in deionized water. The crowns were removed with a universal testing machine or a clinically used removal device (Coronaflex, KaVo). Data were statistically analyzed using nonparametrical tests. Results: Retention values were recorded between 31 N and 362 N. Telio CS Cem showed the lowest retention values, followed by Retrieve, Ketac Cem, and Multilink Implant (P ≤ .0001). The number of removal attempts with the Coronaflex were not significantly different between the cements (P > .05). Thermal cycling and chewing simulation significantly influenced the retrieval of Retrieve Telio CS Cem, and Ketac Cem specimens (P ≤ .05). Only for Multilink Implant and Telio CS Cem correlations between removal with the universal testing machine and the Coronaflex could be revealed (P ≤ .0001). Conclusions: Ketac Cem and Multilink Implant (without silane) can be used for a semipermanent cementation. Retrieve and Telio CS Cem are recommendable for a temporary cementation.