Zirconia Primers Improve the Shear Bond Strength of Dental Zirconia.

PURPOSE: Various resin cements and priming agents are available for adhesive luting of zirconia restorations. The purpose of this study was to investigate how cement type and priming protocol affect the shear bond strength on zirconia ceramics. MATERIALS AND METHODS: Yttria-stabilized tetragonal zirconia polycrystalline ceramic cylinders were bonded to flat zirconia ceramic surfaces using 7 commercially available resin cements. Ten specimens of each cement group were pretreated with a universal primer, and 10 specimens per group were bonded without pretreatment. In addition, 10 specimens per group were pretreated with system-specific zirconia primers, which were available for 3 cements. Altogether, 170 bonded specimens were water-stored, thermal-cycled, and then submitted to shear bond strength tests. The shear bond strength and the fracture types were documented. Differences in shear bond strengths were assessed using 2-way ANOVA with post-hoc test (α = 0.05). A point-biserial correlation was run between the fracture patterns and the shear bond strengths. RESULTS: The mean shear bond strengths of cements in the unprimed group showed large variations between 2.52 ± 3.01 (mean ± SD) MPa and 33.15 ± 7.35 MPa. Pretreating the specimens with a universal primer improved the shear bond strengths significantly in all groups (p < 0.05) with a range of 21.80 ± 12.51 to 57.20 ± 11.40 MPa. The system-specific primers also improved the shear bond strength significantly, compared to the unprimed group (p < 0.01); however, only one system-specific primer achieved a shear bond strength superior to the universal primer (p < 0.01). There was also a statistical correlation between the fracture type and the shear bond strength (p < 0.0005), with cohesively fractured specimens showing higher shear bond strengths (37.24 ± 19.87 MPa) than adhesively fractured specimens (23.10 ± 17.65 MPa) (p < 0.001). CONCLUSION: Using universal primer can enhance the maximal shear bond strength of zirconia.

Dental treatment under general anesthesia in adults with special needs at the University Hospital of Dental Prosthetics and Restorative Dentistry of Innsbruck, Austria: a retrospective study of 12 years.

OBJECTIVES: Special needs patients are prone to insufficient oral care and subsequent caries or periodontitis. The aim of this retrospective study was the assessment of demand for restorative therapy and tooth extractions under general anesthesia in adults with intellectual and/or physical disablement (IPD) or psychiatric disorders (PDs) with inherent dentist phobia at the University Hospital of Innsbruck with regard to demographic factors. MATERIALS AND METHODS: A total of 444 consecutive cases of scheduled dental general anesthesia (DGA) in adults from 2003 to 2014 were included. From patient files, demographic data, the presence of either IPD or a PD, attested by a mandatory certificate, and restorative therapy and tooth extractions performed under DGA were obtained. Data analysis was carried out by means of descriptive and comparative statistics. RESULTS: Four hundred two cases (mean age 37.5 ± 13.87 years) assigned to 283 individuals with IPD and 42 cases (mean age 36.09 ± 13.03 years) assigned to 39 individuals with PDs arose in the observed period. Patients with PDs required significantly more restorations (in 7.98 ± 5.4 versus 5.34 ± 4.41 teeth; p = 0.002; Mann-Whitney U test) and extractions (of 4.86 ± 4.51 versus 2.6 ± 3.96 teeth; p < 0.001; Mann-Whitney U test) than patients with IPD. CONCLUSIONS: Demand for dental treatment was high in the collective of special needs patients. Oral health status was worse in patients with PDs than in patients suffering IPD. CLINICAL RELEVANCE: While in patients with severe disablement, DGA presents the only treatment option, specific preventive programs should be implemented for patients with minor disablement or dentist phobia. In these patients, alternative approaches should be promoted.

CAD/CAM produces dentures with improved fit.

OBJECTIVES: Resin polymerisation shrinkage reduces the congruence of the denture base with denture-bearing tissues and thereby decreases the retention of conventionally fabricated dentures. CAD/CAM denture manufacturing is a subtractive process, and polymerisation shrinkage is not an issue anymore. Therefore, CAD/CAM dentures are assumed to show a higher denture base congruence than conventionally fabricated dentures. It has been the aim of this study to test this hypothesis. MATERIALS AND METHODS: CAD/CAM dentures provided by four different manufacturers (AvaDent, Merz Dental, Whole You, Wieland/Ivoclar) were generated from ten different master casts. Ten conventional dentures (pack and press, long-term heat polymerisation) made from the same master casts served as control group. The master casts and all denture bases were scanned and matched digitally. The absolute incongruences were measured using a 2-mm mesh. RESULTS: Conventionally fabricated dentures showed a mean deviation of 0.105 mm, SD = 0.019 from the master cast. All CAD/CAM dentures showed lower mean incongruences. From all CAD/CAM dentures, AvaDent Digital Dentures showed the highest congruence with the master cast surface with a mean deviation of 0.058 mm, SD = 0.005. Wieland Digital Dentures showed a mean deviation of 0.068 mm, SD = 0.005, Whole You Nexteeth prostheses showed a mean deviation of 0.074 mm, SD = 0.011 and Baltic Denture System prostheses showed a mean deviation of 0.086 mm, SD = 0.012. CONCLUSIONS: CAD/CAM produces dentures with better fit than conventional dentures. CLINICAL RELEVANCE: The present study explains the clinically observed enhanced retention and lower traumatic ulcer-frequency in CAD/CAM dentures.

Do CAD/CAM dentures really release less monomer than conventional dentures?

OBJECTIVES: Computer-aided design (CAD)/computer-aided manufacturing (CAM) dentures are assumed to have more favourable material properties than conventionally fabricated dentures, among them a lower methacrylate monomer release. The aim of this study was to test this hypothesis. MATERIALS AND METHODS: CAD/CAM dentures were generated from ten different master casts by using four different CAD/CAM systems. Conventional, heat-polymerised dentures served as control group. Denture weight and volume were measured; the density was calculated, and the denture surface area was assessed digitally. The monomer release after 7 days of water storage was measured by high-performance liquid chromatography. RESULTS: Whole You Nexteeth and Wieland Digital Dentures had significantly lower mean volume and weight than conventional dentures. Baltic Denture System and Whole You Nexteeth had a significantly increased density. Baltic Denture System had a significantly smaller surface area. None of the CAD/CAM dentures released significantly less monomer than the control group. CONCLUSIONS: All tested dentures released very low amounts of methacrylate monomer, but not significantly less than conventional dentures. A statistically significant difference might nevertheless exist in comparison to other, less recommendable denture base materials, such as the frequently used autopolymerising resins. CLINICAL RELEVANCE: CAD/CAM denture fabrication has numerous advantages. It enables the fabrication of dentures with lower resin volume and lower denture weight. Both could increase the patient comfort. Dentures with higher density might exhibit more favourable mechanical properties. The hypothesis that CAD/CAM dentures release less monomer than conventional dentures could, however, not be verified.

Adjusting dental ceramics: An in vitro evaluation of the ability of various ceramic polishing kits to mimic glazed dental ceramic surface.

STATEMENT OF PROBLEM: During the insertion appointment, the practitioner is often faced with the need to adjust ceramic surfaces to fit a restoration to the adjacent or opposing dentition and soft tissues. PURPOSE: The purpose of this study was to assess the ceramic surface smoothness achieved with various commercially available ceramic polishing kits on different commonly used ceramic systems. The reliability of the cost of a polishing kit as an indicator of improved surface smoothness was assessed. MATERIAL AND METHODS: A total of 350 ceramic surfaces representing 5 commonly available ceramic systems (IPS Empress Esthetic, IPS e.max Press, Cergo Kiss, Vita PM 9, Imagine PressX) were treated with 5 types of ceramic polishing systems (Cerapreshine, 94006C, Ceramiste, Optrafine, Zenostar) by following the manufacturers' guidelines. The surface roughness was measured with a profilometer (Taylor Hobson; Precision Taylor Hobson Ltd). The effects of ceramic systems and polishing kits of interest on surface roughness were analyzed by 2-way ANOVA, paired t test, and Bonferroni corrected significance level. RESULTS: The ceramic systems and polishing kits statistically affected surface roughness (P<.001).The polishing kit Zenostar on IPS e.max Press created the smoothest ceramic surface. No correlation could be established between the high cost of the polishing kit and low surface roughness. None of the commonly used ceramic polishing kits could create a surface smoother than that of glazed ceramic (P<.001). CONCLUSIONS: The inclusion of a diamond polishing paste step is recommended to improve surface smoothness (P<.001). The cost of ceramic polishing kits is not recommended as a reliable indicator of better performance of ceramic polishing kits (P>.30).

Instant dentin hypersensitivity relief of a single topical application of an in-office desensitizing paste containing 8% arginine and calcium carbonate: a split-mouth, randomized-controlled study.

OBJECTIVE: The aim of this study was to evaluate the clinical efficacy of an in-office desensitizing paste containing 8% arginine and calcium carbonate relative to calcium carbonate alone in the reduction of dentin hypersensitivity in a randomized, double-blind, split-mouth clinical trial. MATERIALS AND METHODS: Sixty teeth (30 subjects) with an air blast hypersensitivity score of 2 or 3 (Schiff Cold Air Sensitivity Scale) were randomly assigned to one of two treatment groups: (1) test paste containing 8% arginine and calcium carbonate (elmex sensitive professional desensitizing paste) and (2) control paste: paris white (calcium carbonate). Tactile and air blast dentin hypersensitivity examinations were performed at baseline, immediately after paste application and 4 and 12 weeks later. RESULTS: A statistically significant difference in air blast (p = 0.001) and tactile (p = 0.047) hypersensitivity reduction over time was observed between the two therapy modes. After 12-weeks, statistically significant differences were indicated between the test and control group with respect to baseline-adjusted mean tactile (41.94%; p = 0.038) and air blast hypersensitivity scores (46.5%; p = 0.017). CONCLUSIONS: The tested in-office desensitizing paste containing 8.0% arginine and calcium carbonate provides significantly greater hypersensitivity relief compared to calcium carbonate alone.

Surgical resection technique of a fused supernumerary lateral incisor: a clinical report and review of the literature.

This case report presents the surgical and restorative management of a fused supernumerary left lateral incisor. The diagnosis was confirmed using conventional radiographs and CT. The case report discusses the value of CT for evaluation of the root relationships and describes the varied morphology associated with supernumerary incisors, the surgical resection technique, partial pulpotomy, and restoration with composite resin after mechanical exposure of the remaining tooth's pulp.

Effect of Dentin Bonding Agents, Various Resin Composites and Curing Modes on Bond Strength to Human Dentin.

This study investigated the influence of several dentin bonding agents, resin composites and curing modes on push-out bond strength to human dentin. 360 extracted caries-free third molars were prepared, cut into slices, embedded in epoxy resin and perforated centrally. One half of the specimens (180) were treated by using one-step adhesive systems and the other half (180) with multi-step adhesive systems. Subsequently, the cavities were filled with either universal, flowable or bulk-fill resin composite according to the manufactures' product line and cured with either turbo or soft start program. After storage the push-out test was performed. The data was analyzed using Kolmogorov-Smirnov, three- and one-way ANOVA followed by the Scheffé post-hoc test, unpaired two-sample t-test (p < 0.05). The strongest influence on push-out bond strength was exerted by the resin composite type (partial eta squared ηP2 = 0.505, p < 0.001), followed by the adhesive system (ηP2 = 0.138, p < 0.001), while the choice of the curing intensity was not significant (p = 0.465). The effect of the binary or ternary combinations of the three parameters was significant for the combinations resin composite type coupled adhesive system (ηP2 = 0.054, p < 0.001), only. The flowable resin composites showed predominantly mixed, while the universal and bulk-fill resin composite showed adhesive failure types. Cohesive failure types were not observed in any group. Multi-step adhesive systems are preferable to one-step adhesive systems due to their higher bond strength to dentin. Flowable resin composites showed the highest bond strength and should become more important as restoration material especially in cavity lining. The use of a soft start modus for polymerization of resin composites does not enhance the bond strength to dentin.

Testing the Clinical Applicability of Resin Infiltration of Developmental Enamel Hypomineralization Lesions Using an In Vitro Model.

AIM: The aim of this study is to investigate the penetration abilities of a commercially available low-viscosity resin infiltrant into developmentally hypomineralized teeth in vitro. MATERIALS AND METHODS: Four extracted third molars of a 17-year-old patient with signs of developmental enamel hypomineralization (discoloration, increased opacity, and surface roughness) were infiltrated with a low-viscosity resin mixed with a fluorescent dye, according to the manufacturer's standard protocol. Four extracted molars with sound enamel or showing only initial fissure caries were used as a control group. Specimens were embedded in polymethylmethacrylate, and grindings were prepared. High-resolution projectional radiography of the grindings was performed, and, for one specimen, quantitative micro-computed tomography was used to measure hydroxyapatite density in enamel and dentin lesions. After decalcification, the grindings were examined by reflected bright-field microscopy, wide-field fluorescence microscopy, and confocal laser scanning microscopy. Fluorescence micrographs were superimposed on the radiographs and analyzed correlatively. RESULTS: The pattern of hypo-/demineralization in enamel and dentin in developmentally hypomineralized teeth showed a good congruence with the pattern of resin infiltration. Cavitations and dentin tubules up to a depth of 2 mm beyond cavitations were filled by the infiltrant. In control teeth, the penetration of the infiltrant was limited to decalcified enamel areas (initial fissure caries). CONCLUSIONS: In vitro infiltration of developmentally hypomineralized enamel was successful. CLINICAL SIGNIFICANCE: Resin infiltration might be considered as a routine procedure in the treatment of developmentally hypomineralized teeth. Further investigations with higher sample sizes, different degrees of severity, different stages of lesion extension, and modified treatment protocols are necessary. HOW TO CITE THIS ARTICLE: Schnabl D, Dudasne-Orosz V, et al. Testing the Clinical Applicability of Resin Infiltration of Developmental Enamel Hypomineralization Lesions Using an In Vitro Model. Int J Clin Pediatr Dent 2019;12(2):126-132.

Correlations between AFM and SEM imaging of acid-etched tooth enamel.

Enamel bond strength is an important factor in restorative dentistry and crucially depends on the enamel roughness. To increase roughness, different etching procedures are employed and profilometric estimations, with probe profilometers, including atomic force microscopy (AFM), have been made. However, no correlation between roughness and bond strength has been found. To search for a possible error source leading to the underestimation of enamel roughness when utilizing probe profilometers, the authors compared scanning electron microscopy and AFM images of acid-etched tooth enamel. The results showed that AFM imaging cannot correctly depict the acid-etched enamel surface, because of the high steepness of the enamel crystallites and the generation of convolute images. This leads to a large underestimation of the profilometric parameters measured with AFM, or other profilometers, on acid-etched tooth enamel surfaces.

In Vitro Analysis of the Fracture Resistance of CAD/CAM Denture Base Resins.

Computer-aided design and computer-aided manufacturing (CAD/CAM) denture base manufacturers claim to produce their resin pucks under high heat and pressure. Therefore, CAD/CAM dentures are assumed to have enhanced mechanical properties and, as a result, are often produced with lower denture base thicknesses than conventional, manually fabricated dentures. The aim of this study was to investigate if commercially available CAD/CAM denture base resins have more favourable mechanical properties than conventionally processed denture base resins. For this purpose, a series of three-point bending tests conforming to ISO specifications were performed on a total of 80 standardised, rectangular CAD/CAM denture base resin specimens from five different manufacturers (AvaDent, Baltic Denture System, Vita VIONIC, Whole You Nexteeth, and Wieland Digital Dentures). A heat-polymerising resin and an autopolymerising resin served as the control groups. The breaking load, fracture toughness, and the elastic modulus were assessed. Additionally, the fracture surface roughness and texture were investigated. Only one CAD/CAM resin showed a significantly increased breaking load. Two CAD/CAM resins had a significantly higher fracture toughness than the control groups, and all CAD/CAM resins had higher elastic moduli than the controls. Our results indicate that CAD/CAM denture base resins do not generally have better mechanical properties than manually processed resins. Therefore, the lower minimum denture base thicknesses should be regarded with some caution.

Evaluation of Currently Available CAD/CAM Denture Systems.

PURPOSE: The introduction of computer-aided design/computer-assisted manufacture (CAD/CAM) technology into removable denture prosthodontics enables denture adaptation in fewer patient visits, an advantage that appeals to dentists and patients. Since manufacturers follow very different approaches, an evaluation of the different clinical CAD/CAM complete denture fabrication protocols is desirable. The aim of this article is to assess and evaluate the different clinical fabrication protocols of currently available CAD/CAM denture systems to provide decision support for dental practitioners. MATERIALS AND METHODS: The information for the present article was gathered by questionnaires from (in alphabetical order) Global Dental Science, Merz Dental, Wieland Dental + Technik, Ivoclar Vivadent, VITA Zahnfabrik, and Whole You, and complemented with results from the authors' clinical experience. RESULTS: Wieland Digital Denture involves four patient visits. Both AvaDent digital dentures and Whole You Nexteeth enable denture fabrication in three (including a try-in session) or two (without try-in) visits. Baltic Denture System stipulates complete denture fabrication in two visits, and VITA VIONIC material system is an open system enabling choice between different treatment protocols. It can be combined with several open scanners, CAD software options, and milling machines. CONCLUSION: The available CAD/CAM denture fabrication systems provide a variety of advantages, and the decision on a system should depend on the dentist's prosthodontic expertise, patient throughput rate, and requirements regarding denture individualization.

Is Cognitive Status Related to Oral Hygiene Level and Appropriate for Determining Need for Oral Hygiene Assistance?

BACKGROUND: With declining general health, the maintenance of oral health becomes increasingly difficult. Unfortunately, health care resources are limited. An assessment tool for detecting a patient's need for oral health care assistance would promote its adequate distribution. The aim of this study is to evaluate if the Shulman clock-drawing test score is a suitable assessment tool for determining the need for oral hygiene assistance. METHODS: Data collected from recent dental checkups of 126 inhabitants of five Austrian residential care facilities were analyzed. The Shulman clock-drawing test score was used as a measure for cognitive abilities and related to tooth and denture hygiene indices, which were assessed using the approximal space plaque index (API) and the denture plaque index (DPI). RESULTS: Shulman score values were distributed almost evenly in the study population. The mean API was 83.6% (SD 20.2%) for the maxilla and 94.9% (SD 15.6%) for the mandible. The mean DPI was 43.9% (SD 31.4%). Cognitive impairment was not statistically related to the dental or denture hygiene index. CONCLUSIONS: A high Shulman clock-drawing test score indicates the need for oral hygiene assistance, but it is not suitable as a single tool to assess this need. Patients with other disabilities might equally qualify for assistance. Dentures, however, can be cleaned quickly and efficiently independently of patient compliance; therefore, cleaning the patients' dentures should be part of nursing personnel's daily care routine for every patient.

Longevity of silicate ceramic restorations.

The demand for esthetic restorations has resulted in an increased use of dental ceramics as a biocompatible and functionally sufficient alternative to conventional restorative materials. Silicate ceramic restorations are widely used for veneers, inlays, onlays, and crowns in dentistry. Long-term data are of crucial importance to optimize clinical practice. The purpose of the present article is to summarize data of the Innsbruck ceramic evaluation up to 261 months with the focus on longevity and failure characteristics.

Clinical long-term evaluation and failure characteristics of 1,335 all-ceramic restorations.

PURPOSE: The aim of this clinical retrospective study was to evaluate the clinical quality, estimated survival rate, and failure analysis of different all-ceramic restorations in a long-term analysis of up to 20 years. MATERIALS AND METHODS: Different all-ceramic restorations (crowns [n = 470], veneers [n = 318], onlays [n = 213], and inlays ]n = 334[) were placed in 302 patients (120 men, 182 women) between 1987 and 2009 at Medical University Innsbruck, Innsbruck, Austria. Clinical examination was performed during patients' regularly scheduled maintenance appointments. Esthetic match, porcelain surface, marginal discoloration, and integrity were evaluated following modified California Dental Association/Ryge criteria. Number of restoration failures and reasons for failure were recorded. The study population included 106 (35.1%) individuals diagnosed with bruxism. The success rate was determined using Kaplan-Meier survival analysis. RESULTS: The mean observation time was 102 ± 60 months. Ninety-five failures were recorded. The main reason for failure was fracture of the ceramic (33.68%). The estimated survival rate was 97.3% after 5 years, 93.5% at 10 years, and 78.5% at 20 years. Nonvital teeth showed a significantly higher risk of failure (P < .0001). There was a 2.3-times greater risk of failure associated with existing parafunction (bruxism, P = .0045). Cementation using Variolink showed significantly fewer failures than Optec Cement (P = .0217) and Dual Cement (P = .0099). No significant differences were found for type of restoration and distribution in the mouth. CONCLUSION: All-ceramic restorations offer a predictable and successful restoration with an estimated survival probability of 93.5% over 10 years. Significantly increased failure rates are associated with bruxism, nonvital teeth, and specific cementation agents.

Clinical performance of porcelain laminate veneers for up to 20 years.

PURPOSE: The aim of this clinical retrospective study was to evaluate the clinical quality, success rate, and estimated survival rate of anterior veneers made of silicate glass-ceramic in a long-term analysis of up to 20 years. MATERIALS AND METHODS: Anterior teeth in the maxillae and mandibles of 84 patients (38 men, 46 women) were restored with 318 porcelain veneer restorations between 1987 and 2009 at the Medical University Innsbruck, Innsbruck, Austria. Clinical examination was performed during patients' regularly scheduled maintenance appointments. Esthetic match, porcelain surface, marginal discoloration, and integrity were evaluated following modified California Dental Association/Ryge criteria. Veneer failures and reasons for failure were recorded. The study population included 42 (50.0%) patients diagnosed with bruxism and 23 (27.38%) smokers. The success rate was determined using Kaplan-Meier survival analysis. RESULTS: The mean observation time was 118 ± 63 months. Twenty-nine failures (absolute: 82.76%, relative: 17.24%) were recorded. The main reason for failure was fracture of the ceramic (44.83%). The estimated survival rate was 94.4% after 5 years, 93.5% at 10 years, and 82.93% at 20 years. Nonvital teeth showed a significantly higher failure risk (P = .0012). There was a 7.7-times greater risk of failure associated with existing parafunction (bruxism, P = .0004). Marginal discoloration was significantly greater in smokers (P ⋜ .01). CONCLUSION: Porcelain laminate veneers offer a predictable and successful restoration with an estimated survival probability of 93.5% over 10 years. Significantly increased failure rates were associated with bruxism and nonvital teeth, and marginal discoloration was worse in patients who smoked.

Impact of a prior medical degree on students' dental school performance in Innsbruck, Austria.

The purpose of this study was to identify the performance differences between two groups of Austrian dental students (one with a prior medical degree and one without a medical degree) during their dental school training and final dental licensure examination. A specific aim was to determine if having a medical degree is a predictive factor for dental students' scores on the Austrian Dental Admission Test (Austrian DAT), performance in the dental clinic, and scores on final exam. The study consisted of a retrospective analysis of 122 students (thirty-nine with a medical degree and eighty-three without a medical degree) who were enrolled in the Dental Clinic at Innsbruck Medical University, Innsbruck, Austria, between 2001 and 2006. Three performance categories were considered: Austrian DAT results, clinical performance after the first clinical year in dental school, and performance on the final dental licensure examination. Information on students' age, gender, and previous medical degree was collected from official records. Analyses with student's t-test and Pearson's chi-square test revealed that the students with a medical degree had significantly higher Austrian DAT total test scores, grade point averages after the first clinical year, and scores on the final exam. Additionally, those students had significantly better performance on the final exam in prosthodontics and oral and maxillofacial surgery. The linear regression analysis showed that a medical degree had an independent effect on average scores on the final exam, age, and Austrian DAT test scores, while gender showed no statistically significant effect. Overall, the study found that dental students with a prior medical degree had significantly higher Austrian DAT total test scores and performed significantly better in the first clinical year and on the final exam than those without a prior medical degree.

Comparison of two different veneer preparation designs in vital teeth.

OBJECTIVE: To compare the clinical performance of two different veneer preparation designs (overlap and nonoverlap) on anterior veneer restorations in vital teeth in a retrospective clinical study. METHOD AND MATERIALS: In this study, 292 anterior all-ceramic veneer restorations in vital teeth were clinically examined in 74 patients. The preparation designs were categorized by the amount of tooth reduction on the final casts, with 245 in the overlap and 47 nonoverlap group. RESULTS: After a mean ± SD observation time of 124.25 ± 60.61 months, 20 failures occurred. All failures occurred in the overlap design. Restorations with nonoverlap preparation designs showed significantly fewer failures than restorations with overlap preparation design (P = .018, log-rank). CONCLUSION: Based on the findings of this study, whenever feasible, a preparation design without incisal overlap is recommended, especially in vital teeth..

Clinical performance of all-ceramic inlay and onlay restorations in posterior teeth.

PURPOSE: The aim of this clinical retrospective study was to evaluate the clinical performance and longevity of glass-ceramic onlays and inlays in stress-bearing posterior teeth. MATERIALS AND METHOD: Five hundred forty-seven posterior teeth in the maxillae and mandibles of 120 patients (46 males, 74 females) were restored with 213 onlays, 38 single-surface inlays, 141 two-surface inlays, and 155 three-surface inlays between 1987 and 2009 at Innsbruck Medical University, Innsbruck, Austria, by two experienced dentists. The restoration sample included 9 (1.6%) nonvital teeth and 40 (33%) patients diagnosed with bruxism. The study population was examined clinically during regularly scheduled maintenance appointments. The risk of failure was determined using Kaplan-Meier survival analyses. RESULTS: The mean observation periods for onlays and all inlays were 80 ± 34 months and 111 ± 63 months, respectively. Twenty-seven failures were recorded. The estimated survival rates for onlays and all inlays after 5, 10, and 12 years were 98.9% and 98.9%, 92.4% and 96.8%, and 92.4% and 89.6%, respectively. Nonvital teeth showed a significantly higher risk of failure (P < .001). There was no greater risk of failure associated with existing parafunction (bruxism) (P = .408). Restorations on premolars survived longer in the first 15 years than restorations on molars, but no statistical significance was found (P = .913). CONCLUSION: Glass-ceramic onlays and inlays were demonstrated to be successful in posterior teeth; however, at this time, their efficacy is inferior to that of cast gold restorations.

Impact of a novel dental school admission test on student performance at Innsbruck Medical University, Austria.

Since the year 2000, prospective dental students at Innsbruck Medical University, Innsbruck, Austria, have undergone both theoretical and practical preadmission exams, called the Dental Admission Test (DAT). The aim of this investigation was to assess the suitability and outcome of this selection practice. Five classes from 2001 to 2005 (N=97; forty-three female, fifty-four male) were retrospectively reviewed. DAT results were compared with student performance, gender, ability to graduate on time, and dropout rates. Furthermore, the influence of a previous medical degree was evaluated. The t-test was used to analyze correlations between the results of the DAT and the following: gender, students who graduated on time, and students who had previously completed a medical degree. Pearson's correlation coefficient (r) was applied to analyze correlations among test scores, age, and students' performance during the first clinical year. Students graduating on time were noted to have significantly better DAT results; students with a previous medical degree showed significantly better grades during their first clinical year. The difference between the performance of male and female applicants on the DAT was not significant. Correlation was found between DAT results and dental school performance (r=-0.462). We conclude that the DAT may reduce dropout rates by excluding applicants unlikely to be successful in practical courses and that DAT scores are a reliable tool to predict student performance during the first clinical year of dental school in Innsbruck.