The International Journal of Prosthodontics, 02/2015

Part 1 of this patient report described a prosthetically driven protocol that used computer-aided engineering for the fabrication of a mandibular conversion denture and maxillary provisional complete denture using the AvaDent Digital Denture system. The report demonstrated that this system combined with NobelClinician implant-planning software can be used to efficiently convert a digital denture into an immediately loaded provisional implant-supported fixed complete denture (hybrid prosthesis). Part 2 of the patient report describes the technique and steps involved in the fabrication of a digitally planned and fabricated mandibular fixed complete denture with incorporated titanium milled bar opposed by a definitive computer-aided design/computer-assisted manufacture-milled maxillary complete denture.

Rheumatoid arthritis (RA) is a chronic disease of unknown etiology, characterized by synovitis of the diarthroidal joints, gradual bone erosion, and cartilage destruction. Temporomandibular joint (TMJ) arthritis is frequent in patients with RA, but it is seldom the first joint to be affected. This report presents a case of a female patient with undiagnosed RA who first presented with signs and symptoms of the disease in the TMJs. It highlights the importance of professional awareness and provides a roadmap for clinical and radiologic examination followed by biochemical and genetic monitoring for early diagnosis of RA.

Purpose: This systematic review aimed to identify different prosthodontic outcomes between screw- and cement-retained implant prostheses. Materials and Methods: The relevant articles were retrieved from the following electronic databases: MEDLINE, EMBASE, PubMed (using medical subject headings), and the Cochrane Central Register of Controlled Trials (CENTRAL). The search was performed up to December 31, 2013, and was restricted to studies on human subjects reported in English. A further search was conducted through the reference lists of the articles found as well as from early online articles. Reviewed studies were those on fixed implant prostheses using different retention mechanisms such as screws or cement. Information on types of screws and mechanisms of preloading, as well as different luting cements, was collected in correlation with prosthodontic maintenance/complication issues seen in the clinical studies. Results: Sixty-two papers met the review criteria. There were only six randomized controlled trials and none of them included an equivalent number of screw- and cement-retained single implant crowns for comparison. Studies used different types of screws and only a few reported the preloading procedure for the prosthetic screws. Other studies involving cement-retained implant prostheses used a range of dental cements; however, some did not specify the type used. Studies reported various prosthodontic maintenance/complication issues such as screw loosening, porcelain fracture, loss of retention, and esthetic concerns. Five studies did not report any prosthodontic maintenance issues during their observation periods. More recent studies also did not report any incidence of screw loosening. Only two studies stated the standardized criteria for reporting their prosthodontic maintenance/ complication issues. Conclusions: With inadequate information and various study designs, it was difficult to compare the prosthodontic outcomes between screwand cement-retained fixed implant prostheses. Both retention mechanisms showed prosthodontic maintenance/complication issues that must be considered and this review showed that the introduction of newer implant components may assist in minimizing these issues. It is also recommended that standardized criteria be used when reporting prosthodontic maintenance/complication issues to allow better comparison of data.

Purpose: Studies on the oral health status of institutionalized older adults are less prevalent than those of community-dwelling older adults, as institutionalized older adults tend to be frailer. Poor oral health in older adults has a negative impact on the quality of life and self-confidence of older people and potentially poses a financial burden on both the older adult and society in general. The objective of this study was to assess and compare the oral health status of state institutionalized older adults in Malta with that of their European counterparts. Materials and Methods: A total of 278 older adults with an average age of 83.6 ± 6.5 years from nine state institutions in Malta were randomly selected. Participants were clinically examined for caries, periodontal disease, oral mucosal lesions, and prosthetic status. Results: The oral health status of state institutionalized older adults was poor, with a very low routine dental attendance (29.3%) and, consequently, a high level of treatment need (44.4% of dentate individuals required extractions and 42.1% of dentate individuals required restorations). Only 2% of dentate individuals had healthy periodontal tissues with no clinical attachment loss over 4 mm. Edentulism among state institutionalized older adults stood at 41%. Conclusions: Institutionalized older adults from Malta have a poor oral health status comparable to institutionalized older adults from Europe in general, which poses fiscal and cultural challenges that need to be addressed by the dental community.

This study investigated the effectiveness of intraoral and technical polishing kits. Zirconia specimens were sintered, ground, and polished with 14 different two-step or three-step polishing kits. Surface roughness (Ra, Rz) after each treatment step was determined, and scanning electron micrographs were made. Except for one system, all polishing kits were effective in reducing the surface roughness of ground zirconia. Differences in surface roughness were high after the first polishing step but were reduced to Ra/Rz values similar to or lower than those of the sintered reference after the final polishing step. Achieving smooth surfaces depended on a sequential application of all polishing steps.

Purpose: The purpose of this retrospective study was to evaluate the 5-year clinical performance and failure rate of single- or multiple-unit zirconia-based crowns. Materials and Methods: A total of 148 patients (39 men and 109 women, mean age: 46.9 ± 10.6 years) treated in university and private practices with 618 single- or multiple-unit zirconia-based (Lava) crowns made on natural teeth from January 2007 to December 2008 were included. Two hundred fifty-nine anterior and 359 posterior crowns were examined. A core and/or veneer fracture that required replacement of the restoration was considered to be a failure. The cumulative survival rate (CSR) was described with Kaplan-Meier survival functions. The crowns replaced for other reasons were deemed lost to follow-up, and esthetic, functional, and biologic complications were rated. Results: At the 5-year follow-up, no zirconia core fractures were observed. Twelve veneer fractures that required crown replacement were detected. The CSR was 98.1%. There was a statistically significant difference between survival of the anterior and posterior restorations (P .001). In total, 116 crowns experienced biologic and technical complications. The most common complications were smooth veneer fracture (4, 0.6%), loss of retention (7, 1%), staining because of smoking (24, 4%), and gingival recession (48, 8%). Conclusions: According to the 5-year CSR (98.1%) observed in this study, zirconia-based single or multiple crowns may be considered an acceptable treatment modality for the replacement of anterior and posterior teeth. Results from the current study should be supported by additional randomized clinical trials.

The aim of this study was to investigate the loss of teeth in positions mesially adjacent to implant-supported fixed dentures (IFDs) after insertion of IFDs in unilateral free-end edentulous spaces in the mandible at dental clinics. There were a total of 157 adjacent teeth. Nine adjacent teeth (5.73%, 9 of 157), 9 opposing teeth (2.59%, 9 of 348), 38 posterior teeth (1.93%, 38 of 1,964), and 3 anterior teeth (0.22%, 3 of 1,380) were lost during the observation period. The percentage of lost adjacent teeth was higher than that of posterior teeth (P = .002). Teeth in positions adjacent to the IFDs require more attention than other remaining teeth.

Purpose: The aim of this study was to investigate the effect of case severity on clinical outcomes when fabricating new complete dentures. Materials and Methods: Participants were separated into severe and moderate groups using the index of case difficulty for edentulous patients developed by the Japan Prosthodontic Society. Before and after treatment, self-assessed masticatory ability and oral health-related quality of life (OHRQoL) were examined, and the authors compared them according to case severity using the Mann-Whitney U test. To compare findings before and after treatment, the authors used the Wilcoxon signed rank test. Results: In the severe group, both scores were significantly improved after treatment (P .01). However, in the moderate group, there was no significant difference in self-assessed masticatory ability as measured by the food acceptance score before and after treatment (P = .11). Before treatment, OHRQoL as measured by the Oral Health Impact Profile score was significantly higher in the severe group than in the moderate group (P .01). However, after treatment, there was no significant difference between the two groups (P = .92). Conclusions: The authors concluded that case severity makes a difference in the edentulous patient's OHRQoL and self-assessed masticatory ability during complete denture treatment. Evaluating case severity with the index before treatment is a useful tool for patients and clinicians to predict clinical outcomes.

Oral rehabilitation of adult patients with cleft lip and palate is related to the severity of the anatomical and functional alterations that hamper the proper closure of the nasopharynx. The ideal treatment is closure by bone graft and orthodontics. However, when surgery is not possible or when the patient does not wish to undergo surgery, a palatal prosthesis may offer the best solution in most clinical situations. The authors of this article propose a new classification to help the practitioner with decision making and prosthetic treatment planning for residual palatoalveolar cleft defects.

The incorporation of virtual engineering into dentistry and the digitization of information are providing new perspectives and innovative alternatives for dental treatment modalities. The use of digital surface scanners with surgical planning software allows for the combination of the radiographic, prosthetic, surgical, and laboratory fields under a common virtual scenario, permitting complete digital treatment planning. In this article, the authors present a clinical case in which a guided implant surgery was performed based on a complete digital surgical plan combining the information from a cone beam computed tomography scan and the virtual simulation obtained from the 3Shape TRIOS intraoral surface scanner. The information was imported to and combined in the 3Shape Implant Studio software for guided implant surgery planning. A surgical guide was obtained by a 3D printer, and the surgical procedure was done using the Biohorizons Guided Surgery Kit and its protocol.

The aim of this study was to evaluate the reliability of the impression replica technique with a four-unit zirconia fixed dental prosthesis (FDP). Marginal and internal fit were measured by repeatedly placing the FDP on an epoxy cast using light-body silicone material corresponding to cement. All measured marginal and internal fit points showed varying values. The greatest variations were seen at the most distal margin (33 μm) and at the distal abutment of the FDP (77 μm). The results showed that the technique gives moderate variations and is a useful method to evaluate marginal and internal fit.

Purpose: To evaluate, in situ, the penetration of deposits formed within the subsurface of dentin samples treated with desensitizing dentifrices designed to occlude dentin tubules compared to two controls. Materials and Methods: Twenty-eight healthy participants wore left and right intraoral appliances, each retaining four human dentin samples, for two periods of 4 days. Samples were power-brushed, outside the mouth, twice daily with test products (dentifrices containing 8% strontium or 8% arginine) or control (1,450 ppm NaF or water) and subjected to an agitated grapefruit juice acid challenge on days 3 and 4. Eighteen dentin samples were randomly selected from each treatment group and were dry fractured for scanning electron microscopy and energy-dispersive x-ray spectroscopy analysis. Results: The proportion of cross-sectioned dentin tubules with subsurface occlusion (occluded to a mean of 5 ± 2 μm, range: 1 to 9 μm below the surface) for the 8% strontium group on days 1 and 2 (pre-acid) was 82% (SD: 9%, 95% confidence interval [CI] = 78% to 86%) and on days 3 and 4 (post-acid) was 88% (SD: 10%, CI = 83% to 93%). For 8% arginine on days 3 and 4 (post-acid), the proportion was 78% (SD: 8%, CI = 74% to 82%). These results were statistically significant compared to those for controls (P .01). The 8% arginine on days 1 and 2 (pre-acid) and water and control paste on all days revealed no subsurface deposit. Conclusions: Within the limitations of this study, cross-sectional SEM analysis suggested strontium and arginine dentifrices occlude tubules subsurface in dentin compared to negative controls following acid challenge. The desensitizing dentifrices elicit subsurface changes that may potentiate their effects for the management of dentin hypersensitivity, particularly for patients who consume acidic beverages.

This preliminary study examined laboratory-simulated differences between maxillary complete dentures with and without a palate (palateless) as well as the effect of reinforcement of the latter design. Five types of experimental dentures and three types of reinforcements were made. Strain gauges were attached, and a vertical load was applied. The strain was statistically compared using analysis of variance (P = .05). Strain recordings on the palatal side of palateless dentures without reinforcement were significantly higher than in complete dentures and palateless dentures with reinforcement (P .05). These preliminary observations suggest that such reinforcement with a palatal bar or metal-based palate may reduce the risk of fracture and deformation.

Purpose: Ceria-stabilized zirconia/alumina nanocomposite (Ce-TZP/A) has excellent fracture toughness and bending strength that could be useful for partial denture framework application. The aim of this study was to investigate the effects of threedimensional (3D) geometry on the bending and fatigue properties of a model simulation of Ce-TZP/A clasps. Materials and Methods: Half oval-shaped Ce-TZP/A rods were prepared in six 3D designs. Specimens were either of standard (width divided by thickness: 2.0/1.0 mm) or flat type (2.5/0.8 mm) cross-sectional areas with taper ratios of 1.0, 0.8, or 0.6. As a comparison, cobalt-chromium (Co-Cr) alloy rods of the same shape as the Ce-TZP/A standard shape rod were prepared. All specimens were subjected to the cantilever test and loaded until fracture. They were also cyclically loaded 106 times with various constant displacements, and the maximum displacement prior to fracture was determined for each specimen. Three-dimensional finite element analysis (3D FEA), simulating the cantilever test, was performed to determine the stress distribution during loading. Results: Specimens with the standard cross-sectional shape exhibited higher rigidity and higher fracture loads than the flat specimens by the cantilever test. In addition, lower taper ratios were consistently associated with larger displacements at fracture. Fatigue tests revealed that the maximum displacement prior to fracture of Ce-TZP/A specimens was comparable to that of Co-Cr alloy specimens. The 3D FEA showed that specimens with a taper ratio of 0.6 had the least stress concentration. Conclusions: Ce-TZP/A clasp specimens with a standard cross-sectional shape and a 0.6 taper ratio exhibited the best bending properties among those tested.

To investigate the association between prosthetic rehabilitation and malnutrition in institutionalized elders, 255 nursing home residents were recruited for this study and underwent a comprehensive dental examination. The body mass index (BMI) was administered to estimate the nutritional condition. Participants with BMI 20 kg/m² were categorized as malnourished (n = 33), whereas all others were categorized as adequately nourished (n = 222). The number of teeth present and the prevalence of prosthetic rehabilitation were significantly lower in malnourished participants (P .05). Malnutrition risk was 4.6 times higher for participants who were edentulous and did not wear dentures. Adequate replacement of teeth is important to prevent malnutrition in institutionalized older people.