A randomized clinical trial on zirconia versus titanium implants in maxillary single tooth replacement.

OBJECTIVES: This RCT aimed to compare zirconia and titanium dental implants in the maxillary premolar region. The comparison was based on marginal bone level (MBL) changes, clinical parameters, aesthetic outcomes, and patient related outcome measures (PROMs) 1 year after prosthetic loading. MATERIALS AND METHODS: Fifty patients were randomly assigned to receive either a zirconia (ZrO2, n = 25) implant or a titanium (Ti, n = 25) bone-level implant. Implants were provided with a lithium disilicate crown 3 months after placement. Follow-up was at 1 month and after 1 year. The primary outcome pertained to changes in MBL. Reported secondary outcomes consisted of implant survival, peri-implant tissue health, aesthetics, and PROMs. RESULTS: Mean MBL change after 1 year was 0.01 mm (SD = 0.45; min = 0.72, max = 0.86) for ZrO2 and -0.09 mm (SD = 0.34; min = 0.53, max = -1.06) for Ti (p = .439). Scores for the other clinical outcome parameters and PROMs were generally favorable, with no significant differences. However, significant differences were found for the aesthetic outcomes regarding two criteria: (a) level of facial mucosa (p = .022), in favor of Ti, and (b) root convexity/soft tissue color and texture (p = .005) in favor of ZrO2. CONCLUSION AND CLINICAL IMPLICATIONS: The ZrO2 and Ti implant types used in this study, replacing a single missing maxillary premolar, show a comparable outcome in terms of MBL change after 1 year. Clinical and aesthetic parameters, as well as PROMs, are favorable and similar between both implant types after 1 year of prosthetic loading. These short-term study results suggest that both are suitable for clinical use.

Clinical longevity of intracoronal restorations made of gold, lithium disilicate, leucite, and indirect resin composite: a systematic review and meta-analysis.

OBJECTIVES: The aim of this systematic review and meta-analysis is to assess the comparative clinical success and survival of intracoronal indirect restorations using gold, lithium disilicate, leucite, and indirect composite materials. MATERIAL AND METHODS: This systematic review and meta-analysis were conducted following the Cochrane Handbook for Systematic Reviews of Interventions and PRISMA guidelines. The protocol for this study was registered in PROSPERO (registration number: CRD42021233185). A comprehensive literature search was conducted across various databases and sources, including PubMed/Medline, Embase, Cochrane Library, Web of Science, ClinicalTrials.gov, and gray literature. A total of 7826 articles were screened on title and abstract. Articles were not excluded based on the vitality of teeth, the language of the study, or the observation period. The risk difference was utilized for the analyses, and a random-effects model was applied. All analyses were conducted with a 95% confidence interval (95% CI). The calculated risk differences were derived from the combined data on restoration survival and failures obtained from each individual article. The presence of heterogeneity was assessed using the I2 statistic, and if present, the heterogeneity of the data in the articles was evaluated using the non-parametric chi-squared statistic (p < 0.05). RESULTS: A total of 12 eligible studies were selected, which included 946 restorations evaluated over a minimum observation period of 1 year and a maximum observation period of 7 years. Results of the meta-analysis indicated that intracoronal indirect resin composite restorations have an 18% higher rate of failure when compared to intracoronal gold restorations over 5-7 years of clinical service (risk difference = - 0.18 [95% CI: - 0.27, - 0.09]; p = .0002; I2 = 0%). The meta-analysis examining the disparity in survival rates between intracoronal gold and leucite restorations could not be carried out due to methodological differences in the studies. CONCLUSIONS: According to the currently available evidence, medium-quality data indicates that lithium disilicate and indirect composite materials demonstrate comparable survival rates in short-term follow-up. Furthermore, intracoronal gold restorations showed significantly higher survival rates, making them a preferred option over intracoronal indirect resin-composite restorations. Besides that, the analysis revealed no statistically significant difference in survival rates between leucite and indirect composite restorations. The short observation period, limited number of eligible articles, and low sample size of the included studies were significant limitations. CLINICAL SIGNIFICANCE: Bearing in mind the limitations of the reviewed literature, this systematic review and meta-analysis help clinicians make evidence-based decisions on how to restore biomechanically compromised posterior teeth.

[Is there more to hypodontia then missing teeth?] / Ernstige hypodontie: meer dan alleen ontbrekende gebitselementen?

Dental care professionals regularly see patients with hypodontia. Hypodontia can be acquired, for example through chemotherapy or radiation at a young age, but is hereditary in most patients. Due to an error (pathogenic variant) in one of the many genes that control odontogenesis, the formation of the tooth germ is disrupted at an early stage. The genes involved are not only crucial for tooth development, but they also play an important role in other physical processes. This article provides background information on hypodontia. Based on an inventory of gastrointestinal complaints in patients with hypodontia and a case description of the simultaneous occurrence of a coagulation disorder and hypodontia, the importance of a broad view of this patient group is illustrated. It is concluded that, in addition to a dental assessment, examination of these patients should include a limited physical examination and the medical history of the patient and his close relatives.

[Ceramic implants: the state of art]. / Keramische implantaten: de stand van zaken.

A multitude of biomaterials have been used for the production of implants through the years. Titanium or titanium alloy have been regarded as the 'gold standard' for years. However, potential risks and disadvantages regarding biocompatibility and aesthetics have also been reported for the use of titanium in dental implantology. As such, there is need for an alternative material. Zirconia may be regarded as a possible alternative. It is a ceramic with high fracture toughness and other positive qualities, such as beings metal-free, biocompatible, and white, which is aesthetically desirable. Short-term study results of contemporary zirconia implants are promising and comparable to titanium implants. Nevertheless, the material is relatively brittle and susceptible to surface defects. However, no long-term clinical results exists and possible complications are unknown. Long-term clinical research is needed before zirconia implants routine use may be endorsed.

Clinical survival and performance of premolars restored with direct or indirect cusp-replacing resin composite restorations with a mean follow-up of 14 years.

OBJECTIVES: The objective is to evaluate the long-term clinical survival and performance of direct and indirect resin composite restorations replacing cusps in vital upper premolars. METHODS: Between 2001 and 2007, 176 upper premolars in 157 patients were restored with 92 direct and 84 indirect resin composite restorations as part of an RCT. Inclusion criteria were fracture of the buccal or palatal cusp of vital upper premolars along with a class II cavity or restoration in the same tooth. RESULTS: Forty patients having 23 direct and 22 indirect composite restorations respectively, were lost to follow-up (25.6%). The cumulative Kaplan-Meier survival rates were 63.6% (mean observation time: 15.3 years, SE 5.6%) with an AFR of 2.4% for direct restorations and 54.5% (mean observation time: 13.9 years, SE: 6.4%) with an AFR of 3.3% for indirect restorations. The Cox regression analysis revealed a statistically significant influence of the patient's age at placement on the survival of the restoration (HR 1.036, p = 0.024), the variables gender, type of upper premolar, type of restoration, and which cusp involved in the restoration had no statistically significant influence. Direct composite restorations failed predominantly due to tooth fracture, indirect restorations primarily by adhesive failure (p < 0.05). SIGNIFICANCE: There was no statistically significant difference in survival rates between direct and indirect composite cusp-replacing restorations. Both direct and indirect resin composite cusp-replacing restorations are suitable options to restore compromised premolars. The longer treatment time and higher costs for the indirect restoration argue in favor of the direct technique.

[Deep Margin Elevation for adhesive indirect restorations]. / De coronaalwaarts verplaatste preparatiegrens voor adhesieve indirecte restauraties.

Deep subgingival margin elevation is a much-debated topic in adhesive and restorative dentistry. The hydrophobic trait of adhesive materials challenges the restorative procedure of cavities with deep subgingival margins since bonding and isolation by means of rubber dam is complicated. By relocating the deep subgingival preparation outline to epigingival, or supragingival with a direct composite restoration, the impression procedure and the use of rubber dam is simplified and the bonding of an indirect adhesive restoration can be performed more reliably. In the English-language literature, the term 'Deep Margin Elevation' is reserved for this approach. This article discusses the rationale and clinical implementation of Deep Margin Elevation. The current knowledge about the coronal relocated preparation margin is growing and is tersely summarized in this article with special attention to adhesive bonding between dentine, composites, and ceramic.

Dimensional changes of CAD/CAM polymer crowns after water aging - An in vitro experiment.

Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) polymers can potentially replace traditional materials used for manufacturing indirect restorations. In 2012, Lava Ultimate (LU) was introduced as a highly suitable material for implant-supported single crowns. Three years after its introduction, the manufacturer issued a change in indication for the material, implying that they no longer considered the material to be suitable for crown indications due to debonding issues. A clinical trial with implant-borne Lava Ultimate crowns bonded to zirconia abutments revealed that 80 percent of the LU crowns showed debonding from the abutment within one year, whereas no debonding occurred when an alternative full-ceramic restoration material was used. These results suggest that the material itself had been the cause of the debonding. However, the exact reason for the debonding remained unclear. Water uptake in resin methacrylates like LU is known to cause dimensional changes resulting in mechanical stress on the RelyX Ultimate (RU) cement. The purpose of this study is to quantify the dimensional changes in LU caused by water uptake and relate these dimensional changes to the failure of the RU cement. Twenty-five identical LU-crowns were divided into three groups. 10 LU-crowns with abutment and 10 crowns without abutments were stored in water for 23 days and were only removed for measurement. Five crowns served as a control to calibrate the measurements. The internal diameter was measured eight times with a TS 460 Heidenhain touch probe. For visualization purposes, one crown was also 3D scanned before and after water treatment. The results showed that after 23 days in water the mean increase in diameter for the groups with and without abutment was 36.6 µm (SD = 35,1) and 36.7 µm (SD = 26,5) respectively. Mixed effects modelling indicated no significant between-group differences at any time point. Exposure of LU to water results in dimensional changes causing mechanical stress on the crown-abutment complex. It can be estimated that RU cement fails after an expansion of more than 4 µm. Within the limitations of this in vitro study, it can be concluded that the dimensional changes induced by water uptake can cause debonding issues. As more CAD/CAM polymers for restorative purposes are expected to be developed, the results of this study should stimulate manufacturers to quantify their products' dimensional changes in a wet environment before market release.

Influence of Preparation Design and Restorative Material on Fatigue and Fracture Strength of Restored Maxillary Premolars.

STATEMENT OF PROBLEM: Extensive carious lesions and/or large preexisting restorations possibly contribute to crack formation, ultimately resulting in a fracture that may lead to the loss of a tooth cusp. Hence, preparation design strategy in conjunction with the restorative material selected could be influential in the occurrence of a cuspal fracture. PURPOSE: The purpose of this in vitro study was to evaluate the fatigue behavior and fracture strength of maxillary premolars restored with direct composite and indirect ceramic inlays and overlays, with different preparation depths in the presence or absence of cuspal coverage, and analyze their failure types. METHODS AND MATERIALS: Sound maxillary premolars (N=90; n=10) were divided into nine groups: group C: control; group DCI3: direct composite inlay 3 mm; group DCI5: direct composite inlay 5 mm; group ICI3: indirect ceramic inlay 3 mm; group ICI5: indirect ceramic inlay 5 mm; group DCO3: direct composite overlay 3 mm; group DCO5: direct composite overlay 5 mm; group ICO3: indirect ceramic overlay 3 mm; group ICO5: indirect ceramic overlay 5 mm. In indirect ceramic, lithium disilicate restoration groups, immediate dentin sealing was applied. After restoration, all specimens were tested in fatigue (1,200,000 cycles, 50 N, 1.7 Hz). Samples were critically appraised, and the specimens without failure were subjected to a load to failure test. Failure types were classified and the data analyzed. RESULTS: Zero failures were observed in the fatigue testing. The following mean load to failure strengths (N) were recorded: group ICO5: 858 N; group DCI3: 829 N; group ICO3: 816 N; group C: 804 N; group ICI3: 681 N; group DCO5: 635 N; group DCI5: 528 N; group DCO3: 507 N; group ICI5: 482 N. Zero interaction was found between design-depth-material (p=0.468). However, significant interactions were found for the design-depth (p=0.012) and design-material (p=0.006). Within restorations at preparation depth of 3 mm, direct composite overlays obtained a significantly lower fracture strength in comparison to indirect ceramic onlays (p=0.013) and direct composite inlays (p=0.028). In restorations at depth 5 mm, significantly higher fracture load values were observed in indirect ceramic overlays compared with the inlays (p=0.018). Indirect ceramic overlays on 3 mm were significantly stronger than the deep inlays in ceramic (p=0.002) and tended to be stronger than the deep direct composite inlays. Severe, nonreparable fractures were observed with preparation depth of 5 mm within ceramic groups. CONCLUSIONS: The preparation depth significantly affected the fracture strength of tooth when restored with either composite or ceramic materials. Upon deep cavity preparations, cuspal coverage proved to be beneficial when a glass ceramic was used as the restorative material. Upon shallow cavity preparations, a minimally invasive approach regarding preparation design used in conjunction with a direct composite material was favorable.

[Restoration choices for endodontically treated posterior teeth]. / Restauratieve keuzes voor endodontisch behandelde gebits-elementen in de posterieure zone.

There aren't any generally accepted guidelines for the restoration of an endodontically treated tooth. With a questionnaire among dental general practitioners and endodontists, several restorative treatment options for endodontically treated molars and premolars were identified. The questionnaire inventoried the influence of various parameters on treatment preferences. For each case, additional questions were put about material choice, cuspal coverage and the use of root canal posts. Both groups identified the vertical root fracture as the most common reason for extraction. The dentist general practitioner waited longer than the endodontist to make a permanent restoration in the case of apical periodontitis. Treatment preferences were found to be the same for premolars and molars. In the case of premolars, a root canal post was indicated more often and the location of the wall (bearing/non-bearing) influenced the choice of cuspal coverage. Of the dentist general practitioners and endodontists, 51-53% and 75-94%, respectively, preferred a partial over a full crown preparation in the case of single-walled teeth.

Influence of Deep Margin Elevation and preparation design on the fracture strength of indirectly restored molars.

The objectives of this in-vitro study were to investigate the influence of Deep Margin Elevation (DME) and the preparation design (cusp coverage) on the fracture strength and repairability of CAD/CAM manufactured lithium disilicate (LS2) restorations on molars. Sound extracted human molars (n = 60) were randomly divided into 4 groups (n = 15) (inlay without DME (InoD); inlay with DME (IWD); onlay without DME (OnoD); onlay with DME (OnWD)). All samples were aged (1.2 × 106 cycles of 50N, 8000 cycles of 5-55 °C) followed by oblique static loading until fracture. Fracture strength was measured in Newton and the fracture analysis was performed using a (scanning electron) microscope. Data was statistically analyzed using two-way ANOVA and contingency tables. DME did not affect the fracture strength of LS2 restorations to a statistically significant level (p = .15). Onlays were stronger compared to inlays (p = .00). DME and preparation design did not interact (p = .97). However, onlays with DME were significantly stronger than inlays without DME (p = .00). More repairable fractures were observed among inlays (p = .00). Catastrophic, crown-root fractures were more prevalent in onlays (p = .00). DME did not influence repairability of fractures or fracture types to a statistically significant level (p > .05). Within the limitations of this in-vitro study, DME did not statistical significantly affect the fracture strength, nor the fracture type or repairability of LS2 restorations in molars. Cusp coverage did increase the fracture strength. However, oblique forces necessary to fracture both inlays and onlays, either with or without DME, by far exceeded the bite forces that can be expected under physiological clinical conditions. Hence, both inlays and onlays are likely to be fracture resistant during clinical service.

[Fracture strength of various types of direct and indirect restorations in the functional repair of endodontically treated molars]. / Breuksterkte van verschillende types directe en indirecte restauraties bij het functioneel herstel van endodontisch behandelde molaren.

The fracture strength of endodontically treated molars restored by means of various types of direct and indirect materials was studied in vitro. 105 sound molars were endodontically treated and randomly assigned to 1 control group (endodontic access cavity only) and 6 experimental groups (n = 15) with restorations of the following materials: glass fibre reinforced composite (GFRC); microhybrid composite (C); microhybrid composite restoration with glass fiber post (CP); full-contour lithium disilicate crown (LDS); full-contour lithium disilicate crown with glass fiber post (P-LDS); and an endocrown (EC). Specimens were thermo-mechanically aged and axially loaded until failure. Data were analysed using ANOVA and Tukey's post hoc test (α = 0.05). Fracture strength was significantly affected by the type of restoration (p = 0.000). LDS had significantly higher fracture strength than the control group and GFRC, C and CP groups. Groups EC, LDS and P-LDS were not statistically different from each other in fracture strength. This was also the case with EC, P-LDS and all composite groups. The glass fibre strength of composite restoration resulted in significantly fewer fatal fractures.

Up to 12 years clinical evaluation of 197 partial indirect restorations with deep margin elevation in the posterior region.

OBJECTIVES: Deep margin elevation (DME) relocates the cervical outline of large-sized cavity dimensions in the posterior area supragingivally, using a resin composite in a direct technique. The aim of this study is to evaluate the clinical performance of partial indirect restorations with DME and compare the effects of selected baseline variables on the (quality of) survival of the restorations. METHODS: All teeth that were restored in combination with indirect restorations and DME between 2007 and 2016 were eligible for inclusion. Overall cumulative survival rates were calculated (Kaplan-Meier estimates) and compared among subsets of variables. Qualitative evaluation of all surviving restorations was performed using the modified United States Public Health Service (USPHS) criteria using Chi-square tests. RESULTS: A total of 197 indirect restorations in 120 patients could be included. Restorations or teeth presenting with secondary caries, fracture of the restoration/tooth, debonding of the indirect restoration, root caries, severe periodontal breakdown or pulpal necrosis were considered as absolute failures (n = 8) leading to an overall cumulative survival rate of 95.9% (SE 2.9%) up to 12 years, with an average evaluation time of 57.7 months. Some indication of degradation of the restorations was seen over time. Indirect composite restorations showed more degradation compared to ceramic restorations (p = 0.000). More wear of the antagonist was observed when teeth were opposed to ceramic restorations (p = 0.04). Endodontic treatment negatively impacted the occurrence of fracture of restorations and teeth (p = 0.000). CONCLUSIONS: Indirect restorations with DME have a good survival rate in this study, however longer follow-up is needed as degradation of the restorations is seen over time. CLINICAL SIGNIFICANCE: This long-term study shows the possible clinical applicability of deep margin elevation.

Prospective Randomized Clinical Trial on the Survival of Lithium Disilicate Posterior Partial Crowns Bonded Using Immediate or Delayed Dentin Sealing: Short-term Results on Tooth Sensitivity and Patient Satisfaction.

This prospective randomized clinical trial evaluated tooth sensitivity and patient satisfaction after the provision of partial ceramic restorations bonded using immediate (IDS) or delayed dentin sealing (DDS) on vital molar teeth through a within-subject comparison study. Between December 2013 and May 2016, a total of 30 patients (13 women, 17 men; mean age, 54 years old) received two lithium disilicate ceramic (IPS-e.max press, Ivoclar Vivadent) partial restorations on vital first or second molar teeth (N=60). The two teeth randomly received either IDS (test group, n=30) or DDS (control group, n=30). Partial preparations were performed on all teeth and directly after tooth preparation. IDS was achieved using self-etch adhesive (Clearfil SE Primer and Adhesive, Kuraray) followed by the application of flowable resin (Clearfil Majesty Flow, Kuraray). Partial ceramic restorations were bonded (Variolink Ultra, Ivoclar Vivadent) two weeks after preparation. The teeth were evaluated preoperatively and at one week, three months, and 12 months postoperatively using a cold test and a questionnaire for perceived tooth sensitivity. Patient satisfaction was evaluated using a visual analog scale (VAS). Data were analyzed using McNemar, chi-squared, and Wilcoxon signed rank tests (α=0.01). There was no significant difference in patient-reported tooth sensitivity between the preoperative phase and all other time points (p>0.01). There was also no significant difference between IDS and DDS (p>0.01) for all items on the questionnaire. VAS scores did not differ significantly between the IDS and DDS groups for all items in the questionnaire at all time points (p>0.01). No tooth sensitivity change was noticed with the application of partial ceramic indirect restorations. This clinical study could not confirm that IDS is more advantageous than DDS in terms of tooth sensitivity and patient satisfaction at 1 year of clinical service of partial ceramic restorations.

Randomized clinical trial on indirect resin composite and ceramic laminate veneers: Up to 10-year findings.

OBJECTIVES: In this randomized split-mouth clinical trial the survival rate and quality of survival of indirect resin composite and ceramic laminate veneers were evaluated. METHODS: A total of 48 indirect resin composite (Estenia; n = 24) and ceramic laminate veneers (IPS Empress Esthetic; n = 24) were placed on maxillary anterior teeth. Veneer preparations with incisal overlap were performed using a mock up technique. Survival of the restoration was considered the primary outcome measure and reported using Kaplan-Meier statistics and survival curves compared by means of Log Rank (Mantel-Cox) test. After luting, restorations were evaluated by calibrated operators at baseline and every year thereafter, using modified USPHS criteria and compared by means of Mann-Whitney U test. RESULTS: In total, 6 failures were observed, consisting of debonding (n = 3) and fracture (n = 3), all in the group of the indirect resin composite laminate veneers. Cumulative chance on survival after 10 years of the indirect resin composite and ceramic veneers was 75% (se 3,8%) and 100% respectively (p = 0.013). Of the surviving 42 laminate veneers, the variables 'color match' (p = 0.002), 'surface roughness' (p = 0.000), 'fracture of the restoration' (p = 0.028), and 'wear of the restoration' (p = 0.014), were significantly less favourable among the composite laminate veneers as well. CONCLUSIONS: The ceramic veneers on maxillary anterior teeth in this study performed significantly better compared to the composite indirect laminate veneers after a decade, both in terms of survival rate and in terms of quality of the surviving restorations. CLINICAL RELEVANCE: When indicated, anterior ceramic laminate veneers may be preferred over indirect composite laminate veneers.

Effect of Immediate Dentin Sealing and Surface Conditioning on the Microtensile Bond Strength of Resin-based Composite to Dentin.

This study evaluated the microtensile bond strength (µTBS) of resin-based composite (RBC) to dentin after different immediate dentin sealing (IDS) strategies and surface-conditioning (SC) methods and on two water storage times. Human molars (n=48) were randomly divided into eight experimental groups involving four different IDS strategies-IDS-1L with one layer of adhesive, IDS-2L with two layers of adhesive, IDS-F with one layer of adhesive and one layer of flowable RBC, and DDS (delayed dentin sealing) with no layer of adhesive (control)-and two different SC methods-SC-P with pumice rubbing and SC-PC with pumice rubbing followed by tribochemical silica coating. The µTBS test was performed after one week and after six months of water storage, being recorded as the "immediate" and "aged" µTBS, respectively. Composite-adhesive-dentin microspecimens (0.9×0.9×8-9 mm) were stressed in tension until failure to determine the µTBS. Failure mode and location of failure were categorized. Two-way analysis of variance was applied to analyze the data for statistically significant differences between the experimental groups (p<0.05). Two-way analysis of variance revealed no significant differences between the one-week µTBS specimens for IDS strategy (p=0.087) and SC methods (p=0.806). However, the interaction of IDS strategy and SC methods appeared statistically significant (p=0.016). The six-month specimen evaluation showed no significant difference in µTBS for SC (p=0.297) and SC/IDS interaction (p=0.055), but the µTBS of the IDS strategies differed significantly among them (p=0.003). For tribochemical silica-coated IDS, no significant effect of aging on µTBS was recorded (p=0.465), but there was a highly significant difference in µTBS depending on the IDS strategy (p<0.001). In addition, the interaction of IDS and aging was borderline statistically significant (p=0.045). The specimens failed mainly at the adhesive-dentin interface for all experimental groups. Dentin exposure during clinical procedures for indirect restorations benefits from the application of IDS, which was shown to result in higher bond strength. No significant differences were found between cleaning with solely pumice or pumice followed by tribochemical silica coating.

Randomized clinical trial on the survival of lithium disilicate posterior partial restorations bonded using immediate or delayed dentin sealing after 3 years of function.

OBJECTIVES: The survival and success rate and the quality of survival of partial ceramic restorations bonded employing Immediate (IDS) or Delayed Dentin Sealing (DDS) in vital molar teeth were evaluated in a randomized clinical trial with within-subject comparison study. MATERIALS AND METHODS: 30 patients received two lithium disilicate ceramic (IPS-e.max press, Ivoclar Vivadent) partial restorations on vital first or second molar teeth (N = 60). The two teeth randomly received either IDS (test group, n = 30) or DDS (control group, n = 30). Partial ceramic restorations were luted (Variolink Ultra, Ivoclar Vivadent) two weeks after preparation. Evaluations were performed at 1 week, 12 months and 36 months post-operatively, using qualitative (FDI) criteria. Representative failures were evaluated microscopically (SEM) and by means of simplified qualitative fractography analysis. RESULTS: One absolute failure occurred in the DDS group due to (secondary) caries. The overall survival rate according to Kaplan-Meier after 3 years was 98.3% (FDI criteria score 1-4, n = 59) and the overall success rate was 85% (FDI criteria score 1-3, n = 51), with no significant difference between restorations in the IDS and DDS group (p = 0.32; Kaplan-Meier, Log Rank (Mantel-Cox), CI = 95%). For the quality of the survival, no statistically significant differences were found between IDS and DDS (p = 0.7; Kaplan-Meier, Log Rank (Mantel-Cox), CI = 95%) restorations on any follow-up timepoints for any of the FDI criteria (Wilcoxon, McNemar, p > 0.05). CONCLUSION: Adhesively luted partial ceramic restorations in vital molar teeth have a good prognosis, however IDS did not show any differences in success and survival rates after 3 years of function.

Fracture Strength of Various Types of Large Direct Composite and Indirect Glass Ceramic Restorations.

INTRODUCTION: The objective of this study was to investigate the mechanical behavior of severely compromised endodontically treated molars restored by means of various types of composite buildups, full-contour lithium disilicate crowns (with or without post) or a lithium disilicate endocrown. METHODS AND MATERIALS: One hundred five sound molars were endodontically treated and randomly assigned to 1 control group (endodontic access cavity only) and 6 experimental groups (n=15): glass fiber reinforced composite (GFRC group), direct microhybrid composite (C group), direct microhybrid composite restoration with glass fiber post (CP group), composite buildup and full-contour lithium disilicate crown (LDS group), additional glass fiber post (P-LDS group), and endocrown (EC group). Molar crowns in the treatment groups were removed 1 mm above the cementoenamel junction and restored. All specimens were thermomechanically aged (1.2×106 cycles at 1.7 Hz/50N, 8000 cycles 5°C to 55°C) and axially loaded until failure. Data were analyzed using analysis of variance and Tukey post hoc test (α=0.05). RESULTS: Fracture strength was significantly affected by the type of restoration (p=0.000; statistically similar groups identified with superscript letters): LDSB (3217±1052 N), P-LDSAB (2697±665 N), ECAB (2425±993 N), CA (2192±752), controlA (1890±774 N), CPA (1830±590 N), and GFRCA (1823±911 N). Group GFRC obtained significantly more repairable fractures than the other groups. CONCLUSIONS: Significant differences in fracture strength were obtained between LDS, the composite restorations, and control group. Direct composite restorations showed similar fracture strength as P-LDS and EC. Incorporating a glass fiber reinforced composite resulted in significantly more repairable failures.

[The pink and white aesthetics of a new zirconia implant]. / De roze en witte esthetiek van een nieuw zirkoniumdioxide implantaat.

Zirconia implants can offer a good alternative to titanium implants. Due to their specific material properties, they have the potential for a more appealing aesthetic result, which can be particularly important in the anterior zone. In the present study, the pink and white aesthetics of immediately placed zirconia implants in the anterior maxillary zone in 20 patients were assessed on the basis of Pink and White Esthetic Scores (PES and WES). To this end, two clinical photographs were compared: one taken immediately after placement of the permanent crown (mean PES = 12.8; mean WES = 8.5) and the other one taken at a later time (mean PES = 12.8; mean WES = 8.6). No statistically significant difference was found between the two moments. Volunteers found it difficult to correctly identify the implant among the other front teeth. Patients completed a questionnaire regarding the aesthetics of the pink and white implant and they graded the final result with an 8.5 score on a point scale of 0 to 10. The aesthetic appearance of a zirconia implant is excellent and stable over time. Patients are generally satisfied with the result.

A systematic review and meta-analysis of 3-unit fixed dental prostheses: Are the results of 2 abutment implants comparable to the results of 2 abutment teeth?

The purpose of the systematic review and meta-analysis was to compare the performance of 3-unit bridges on teeth with 3-unit bridges on implants, evaluating survival of the bridges, survival of the teeth or implants, condition of the hard and soft tissues surrounding the supports, complications and patient-reported outcome measures (PROM) after a mean observation period of at least 1 year. A literature search was conducted using a combination of the search terms: fixed partial denture and fixed dental prostheses (FDPs). An electronic search for data published until January 2017 was undertaken using the MEDLINE, EMBASE and Cochrane Library databases. Eligibility criteria included clinical human studies, either randomised or not, interventional or observational, which evaluated the results of 3-unit FDPs on either 2 implants or 2 abutment teeth. The search identified 1686 unique references. After applying eligibility criteria, 66 articles were included in the analysis. A total of 1973 3-unit FDPs were supported by teeth, and 765 were implant-supported. No significant differences were found either in the survival of the supporting abutments (P = .52; 99% vs 98.7% survival per year) or in the survival of the prostheses (P = .34; 96.4% vs 97.4% survival per year). Both treatments show an almost equally low complication rate, but there is a low level of reporting of hard and soft tissue conditions and PROM. It is concluded that implant-supported 3-unit FDPs seem to be a reliable treatment with survival rates not significantly different from the results of teeth-supported 3-unit FDPs.

On the bulk degradation of yttria-stabilized nanocrystalline zirconia dental implant abutments: an electron backscatter diffraction study.

Degradation of yttria-stabilized zirconia dental implants abutments due to the tetragonal to monoclinic phase transformation was studied in detail by microstructural characterization using Electron Back Scatter Diffraction (EBSD). The amount and distribution of the monoclinic phase, the grain-size distribution and crystallographic orientations between tetragonal and monoclinic crystals in 3 mol.% yttria-stabilized polycrystalline zirconia (3Y-TZP) were determined in two different types of nano-crystalline dental abutments, even for grains smaller than 400 nm. An important and novel conclusion is that no substantial bulk degradation of 3Y-TZP dental implant abutments was detected after 1 year of clinical use.