The International Journal of Prosthodontics, 06/2012

Purpose: This study aimed to review published quantitative studies for evidence regarding the influence of oral rehabilitation following total or partial tooth loss on self-perceived oral health-related quality of life (OHRQoL). Materials and Methods: Three databases were searched using specified indexing terms. The reference lists of relevant publications were also searched manually. Quality of evidence was classified according to GRADE guidelines as high, moderate, low, or very low. Results: The search yielded 2,138 titles and abstracts, 2,102 of which were of a quantitative study design. Based on pre-established criteria, the full-text versions of 322 articles were obtained. After data extraction and interpretation, 5 publications of high or moderate study quality remained. The results of these 5 studies showed positive effects of oral rehabilitation on OHRQoL. Two studies showed substantial improvements. Conclusions: This is a relatively new field of research; there are very few quantitative studies of how patients perceive OHRQoL following tooth loss and subsequent rehabilitation. While this review indicates that treatment has positive effects on quality of life, the scientific basis is insufficient to support general conclusions about the influence of various interventions on the OHRQoL of patients who have experienced total or partial tooth loss. To achieve a more comprehensive analysis, it is recommended that future studies be based on a combination of quantitative and qualitative methods, ie, questionnaires and semi-structured interviews. The follow-up period must also be appropriate for the specific intervention studied.

Purpose: This study aimed to evaluate the outcomes of treatment methods used to rehabilitate adult patients with maxillary and/or mandibular edentulism after at least 5 years of follow-up. The risks, adverse effects, and cost effectiveness of these methods were also evaluated. Materials and Methods: Three databases as well as the reference lists of included publications were searched using specified indexing terms. Publications that met the inclusion criteria were read and interpreted using pre-established protocols. Quality of evidence was classified according to the GRADE system (high, moderate, low, or very low). Results: The search yielded 2,130 titles and abstracts. Of these, the full-text versions of 488 publications were obtained. After data extraction and interpretation, 10 studies with moderate study quality of evidence and 1 study with low quality of evidence regarding outcomes, risks, and adverse effects remained. Three studies on the economic aspects of treatment were also included (1 with moderate quality and 2 with low quality). Low-quality evidence showed that the survival rate of implant-supported fixed prostheses is 95% after 5 years in patients with maxillary edentulism and 97% after 10 years in patients with mandibular edentulism. The survival rate of implant-supported overdentures is 93% after 5 years (low-quality evidence). In implant-supported fixed prostheses, 70 of every 1,000 implants are at risk of failing in the maxilla after 5 years and 17 of every 1,000 implants in the mandible are at risk after 10 years. Regarding economic aspects, the evidence was insufficient to provide reliable results. Conclusions: Due to the low quality of evidence found in the included studies, further research with a higher quality of evidence is recommended to better understand the outcomes of treatment for patients with maxillary and/or mandibular edentulism.

Purpose: The purpose of this systematic review was to identify and critically appraise published studies of treatment methods used in general practice to rehabilitate adult patients with single tooth loss or partial edentulism, with special emphasis on outcomes reported after at least 5 years of follow-up. Materials and Methods: Three databases were searched using specified indexing terms. Publications were included if the study design, research questions, and sample size satisfied pre-established criteria. Reference lists of relevant publications and systematic reviews were also searched. The quality of evidence was classified according to the GRADE system as high, moderate, low, or very low. Results: The search yielded 7,675 titles, of which 1,130 were read in full text. A final total of 15 publications were deemed eligible for inclusion: 5 of moderate quality and 10 of low quality. The five studies of moderate quality were all related to implant-based treatment. The 5-year survival rates for implant-supported single crowns and prostheses were 91% and 94.7%, respectively (implant survival rates: 98.5% and 94.9%, respectively). The underlying scientific evidence was low in quality. No relevant publications were identified regarding the economic aspects of treatment. Conclusion: Due to the low scientific evidence of the included studies, it was not possible to compare various treatment methods used for rehabilitation of single tooth loss or partial edentulism.

This study aimed to determine the effect of the taper and height of tooth preparations on the fracture strength and retention of zirconia crowns. Sixty-four dies were designed to simulate a crown preparation. Dies were machined with a height of either 4 mm (n = 16) or 7 mm (n = 16) and a taper of either 6 degrees (n = 16) or 20 degrees (n = 16). Copings were created from Lava zirconia blanks. Retention tests were performed using a universal testing machine. Copings were recemented on the dies, thermocycled, and tested for fracture strength. Data were analyzed using factorial analysis of variance. Retention was greater in the taller and less-tapered preparation designs. Taller preparations showed superior fracture strength. Preparing posterior teeth with higher axial walls and less taper is recommended to achieve increased retention and strength for zirconia crowns.

This study aimed to evaluate three- and four-unit posterior fixed partial dentures (FPDs) with zirconia frameworks after 5 years of function. Of the initial 30 subjects, 25 patients with 25 FPDs were examined after a mean follow-up period of 62.1 months. Five patients were not available for recall visits. Two FPDs failed before the 60-month evaluation because of framework fracture or delamination of the veneering ceramic after endodontic treatment. The 5-year survival rate was 92%. Based on these results, it can be suggested that zirconia frameworks have sufficient mechanical requirements for use in the stress-bearing posterior region. Major fracture of the ceramic veneer could be related to inadequate framework design or bruxism.

Purpose: This systematic review reports on the survival of feldspathic porcelain veneers. Materials and Methods: The Cochrane Library, MEDLINE (OVID), Embase, Web of Knowledge, selected journals, clinical trials registers, and conference proceedings were searched independently by two reviewers. Academic colleagues were also contacted to identify relevant research. Inclusion criteria were human cohort studies (prospective and retrospective) and controlled trials assessing outcomes of feldspathic porcelain veneers in more than 15 patients and with at least some of the veneers in situ for 5 years. Of 4,294 articles identified, 116 studies underwent full-text screenings and 69 were further reviewed for eligibility. Of these, 11 were included in the qualitative analysis and 6 (5 cohorts) were included in meta-analyses. Estimated cumulative survival and standard error for each study were assessed and used for meta-, sensitivity, and post hoc analyses. The I2 statistic and the Cochran Q test and its associated P value were used to evaluate statistical heterogeneity, with a random-effects meta-analysis used when the P value for heterogeneity was less than .1. Galbraith, forest, and funnel plots explored heterogeneity, publication patterns, and small study biases. Results: The estimated cumulative survival for feldspathic porcelain veneers was 95.7% (95% confidence interval [CI]: 92.9% to 98.4%) at 5 years and ranged from 64% to 95% at 10 years across three studies. A post hoc meta-analysis indicated that the 10-year best estimate may approach 95.6% (95% CI: 93.8% to 97.5%). High levels of statistical heterogeneity were found. Conclusions: When bonded to enamel substrate, feldspathic porcelain veneers have a very high 10-year survival rate that may approach 95%. Clinical heterogeneity is associated with differences in reported survival rates. Use of clinically relevant survival definitions and careful reporting of tooth characteristics, censorship, clustering, and precise results in future research would improve meta-analytic estimates and aid treatment decisions.

Purpose: This study aimed to investigate the clinical outcome and estimated cumulative survival rate of feldspathic porcelain veneers in situ for up to 21 years while also accounting for clustered outcomes. Materials and Methods: Porcelain veneers (n = 499) placed in patients (n = 155) by a single prosthodontist between 1990 and 2010 were sequentially included, with 239 veneers (88 patients) placed before 2001 and 260 veneers (67 patients) placed thereafter. Nonvital teeth, molar teeth, or teeth with an unfavorable periodontal prognosis were excluded. Preparations had chamfer margins, incisal reduction, palatal overlap, and at least 80% enamel. Feldspathic veneers from refractory dies were etched (hydrofluoric acid), silanated, and bonded. Many patients received more than 1 veneer (mean: 5.8 ± 4.3). Clustered outcomes were accounted for by randomly selecting (random table) 1 veneer per patient for analysis. Clinical outcome (success, survival, unknown, dead, repair, failure) and Kaplan-Meier estimated cumulative survival were reported. Differences in survival were analyzed using the log-rank test. Results: For the random sample of veneers (n = 155), the estimated cumulative survival rates were 96% ± 2% (10 years) and 96% ± 2% (20 years). For the entire sample, the survival rates were 96% ± 1% (10 years) and 91% ± 2% (20 years). Survival did not statistically differ between these groups (P = .65). Seventeen veneers in 8 patients failed, 75 veneers in 30 patients were classified as unknown, and 407 veneers in 130 patients survived. Multiple veneers in the same mouth experienced the same outcome, clustering the results. Conclusions: Multiple dental prostheses in the same mouth are exposed to the same local and systemic factors, resulting in clustered outcomes. Clustered outcomes should be accounted for during analysis. When bonded to prepared enamel substrate, feldspathic porcelain veneers have excellent long-term survival with a low failure rate. The 21-year estimated cumulative survival for feldspathic porcelain veneers bonded to prepared enamel was 96% ± 2%.

This preliminary study investigated the effect of a mandibular advancement device on upper airway collapsibility in seven patients with obstructive sleep apnea. Overnight polysomnography and dynamic magnetic resonance imaging were performed at the retropalatal and retroglossal levels, and the apnea-hypopnea Index (AHI), anteroposterior and lateral distances, and airway volumes were recorded. The tests were repeated following a 3-month period of wearing a customized mandibular advancement device. A significant reduction in AHI (from 31 events per hour to 18.2 events per hour) and improvement in airway dimension at both the retropalatal and retroglossal levels were recorded, suggesting a baseline record for future studies with a larger patient sample.

The purpose of this preliminary investigation was to assess the influence of palatal morphology on deformation of maxillary complete dentures in vivo. The palatal morphology of the maxillae of eight edentulous subjects was measured. Experimental dentures were fabricated, and a strain gauge was attached at the first molar position at the midline of the polished surface of each denture. Subjects were instructed to bite a metal bar placed bilaterally at the denture's first molar region with a force of 49 N. The resultant strains were recorded, and the correlation between strain and palatal morphology was evaluated using the Pearson correlation coefficient. A strong correlation between strain and both palatal depth and radius of curvature was noted, suggesting that edentulous patients with wide, shallow palates have a higher risk of denture deformation, which may lead to material fracture.

The aim of this prospective study was to evaluate the clinical outcomes of threeand four-unit posterior fixed dental prostheses (FDPs) made of In-Ceram Zirconia. Twenty FDPs were inserted in 15 patients. Over a mean observation period of 74.6 months, the survival rate was 85%. Sixty-five percent of cases did not allow for connector dimensions that met the manufacturer's recommendations without the use of surgical procedures (eg, crown lengthening). Posterior all-ceramic FDPs made of In-Ceram Zirconia appear to be a viable prosthetic treatment option to replace a missing tooth.

Purpose: This study aimed to investigate (1) the influence of complete denture quality and years of denture use on masticatory efficiency and (2) the relationship between complete denture quality and years of use. Materials and Methods: A cross-sectional study was conducted with 93 edentulous patients (mean age: 65.6 years) wearing both mandibular and maxillary dentures. Patients were classified into two categories according to years of denture use: = 2 years and >= 5 years. Masticatory efficiency was evaluated via the colorimetric method with beads as the artificial test food. A reproducible method for objective evaluation of the technical quality of complete dentures was employed. The association between denture quality and years of denture use was analyzed using chi-square and Fisher exact tests. The results of masticatory efficiency testing were analyzed using two-way analysis of variance (with the Tukey post hoc test) in terms of years of denture use (= 2 years, >= 5 years) and denture quality (poor, average, good). Results: A significant relationship was found between denture quality and years of denture use (P .05). Masticatory efficiency differed significantly (P .05) between patients with = 2 years of denture use (0.101 ± 0.076 absorbance) and >= 5 years of use (0.068 ± 0.076 absorbance). Masticatory efficiency was not influenced by denture quality. Conclusions: Complete denture quality and masticatory efficiency significantly decreased over time. However, complete denture quality did not influence masticatory efficiency.

Facial prostheses aim to restore the appearance, contours, and esthetics of the face while consequently enhancing patients' self-esteem and reintegration into social life. Restoring unilateral missing ocular and orbital tissues is a challenging task that requires great skill from the clinician (anaplastologist) to accurately mimic the opposing natural tissues. Bilateral defects present additional technical and clinical challenges for clinicians and patients alike. This article presents two cases involving restoration of the ocular and orbital components of bilaterally blind patients. The first case comprised the construction of indwelling scleral eye shells for both eyes, while the second comprised left orbital (implant-retained) and right indwelling eye shell prostheses. Custom-made bilaterally indwelling eyes are more esthetically pleasing than stock options and show better fit and comfort following conventional impression techniques. Clinical challenges include impression taking, prosthesis fabrication, identification of the correct orientation into the socket, communication with the patient, and satisfaction of patient expectations. Since both patients were blind, their families played a vital role in describing their prostheses and thus in improving the patients' self-esteem and satisfaction with treatment.