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.

[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.

[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.

[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.

[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.

[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.

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.

[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.

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.

Prosthetic treatment outcome in patients with severe hypodontia: a systematic review.

Severe hypodontia (≥6 missing teeth) is associated with aesthetic and functional problems. Its presentation is heterogenic, and a variety of treatment modalities are used resulting in different treatment outcomes. As there is currently no standard treatment approach for patients with severe hypodontia, the literature was systematically reviewed with the focus on treatment outcomes. Medline, Embase and The Cochrane Central Register of Controlled Trials were searched (last search 24 August 2015). This was completed with a manual search of the reference lists of the selected studies. To be included, studies had to describe dental treatment outcome measure(s) in patients with severe hypodontia; there were no language restrictions. The methodological quality was assessed using MINORS criteria. Twenty-one studies were eligible, but the diversity in type and quality did not allow for a meta-analysis; seventeen studies had a retrospective design; sixteen studies described the results of implant treatment. Treatment with (partial) dentures, orthodontics, fixed crowns or bridges was sparsely presented in the eligible studies. Implant survival, the most frequently reported treatment outcome, ranging from 35·7% to 98·7%, was influenced by 'location' and 'bone volume'. The results of implant treatment in severe hypodontia patients are promising, but due to its heterogenic presentation, its low prevalence and the poor quality of the studies, evidence-based decision-making in the treatment of severe hypodontia is not yet feasible, thus prompting further research.

[Effectivity and durability of telescopic dentures on abutment teeth]. / Doelmatigheid en duurzaamheid van telescoopprothesen op pijlerelementen.

In a study, the effectivity and durability of telescopic dentures on abutment teeth provided with telescope crowns were investigated. The prognosis for the prosthetic structure and for the abutment teeth were both investigated. The survival rate of 234 telescopic dentures (886 abutment teeth) in 147 patients in a general dental practice were retrospectively evaluated on the basis of a status study. The mean survival rate was calculated. This is the moment when 50% of the telescopic dentures had failed. For telescopic dentures in the maxilla, this was 22.3±2.8 years, which did not represent a statistically significant difference from the mandible (20.9±1.9 years). Of the 886 abutment teeth that were used, 127 (14.3%) were extracted after an average period of 11.7 years. Periodontal complications were the primary reason for extraction. Based on this investigation, one could conclude that telescopic dentures are also a durable and sustainable solution in the long term. Loss of abutment teeth is relatively rare and has limited influence on the survival of the prosthetic structure.

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.

[Dizziness and nausea following implant placement]. / Duizeligheid en nausea na het plaatsen van implantaten.

A patient suffered from episodes of dizziness and nausea immediately after the placement of 4 implants in his edentulous maxilla. During the treatment implant drills and osteotomes had been used. During the following 6 months, the complaints disappeared gradually. The presentation fitted the not very well-known diagnosis traumatic labyrinthine concussion. Before treating patients with oral implants in the maxilla, it is necessary to inform them about this potential invalidating complication. The complication can be prevented by using a screw-type bone spreader, which renders the use of a surgical hammer unnecessary.

[Treatment of a single-tooth space in the occlusal system]. / Behandeling van een enkelvoudig diasteem in het occlusiesysteem.

The space created by the absence of 1 not-free-ending tooth in an occlusal system can be indicated as a single-tooth space. For treating a single-tooth space, several options are available to restore the functions of the occlusal system. Feasible options are a resin-bonded fixed prosthesis, a conventional fixed prosthesis, and an implant-supported restoration. Implant-supported restorations have a good prognosis, high patient satisfaction, and the advantage that adjacent teeth are not involved in the treatment. Anxiety about surgical treatment, the width of the single-tooth space, and financial aspects may be reasons not to consider an implant-supported restoration as first-choice treatment.

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.

Mandibular implant-supported overdentures and oral function.

OBJECTIVES: Oral rehabilitation by means of implant-retained mandibular overdentures is known to improve oral function. The aim of this study was to evaluate the long-term effects of mandibular implant treatment on oral function. We quantified maximum bite force and masticatory performance 10 years after implant treatment. It was hypothesized that these outcome measures would not change in this period. MATERIALS AND METHODS: Eighteen edentulous patients were scheduled for re-evaluation of their oral function 10 years after they had participated in a randomized cross-over clinical trial. In that trial, they had received two mandibular implants and a new denture with successively magnet-, ball-socket, and bar-clip attachments. RESULTS: At the 10-year follow-up, 14 of the initial 18 patients participated in the evaluation. As a result of the implant treatment, the average maximum bite force more than doubled, from 162 to 341 N, whereas the average number of chewing cycles to halve the initial particle size decreased from 55 to 27 cycles. No significant changes in maximum bite force and masticatory performance were observed after 10 years. However, the average maximum bite force obtained with implant-retained overdentures is still significantly lower than that of dentate subjects (569 N). CONCLUSION: Maximum bite force and masticatory performance significantly increased after implant treatment and remained unaltered during the following 10-year period. Thus, implant treatment greatly improves oral function for a long period of time.

[Haematoma of the floor of the mouth following implant surgery]. / Hematoom in de mondbodem na een implantaatbehandeling.

A patient experienced severe bleeding in the floor of the mouth as a consequence of the placement of 2 implants in the resorbed anterior segment of the mandible. The resulting swelling of the floor of the mouth caused a life-threatening obstruction of the trachea. The patient was urgently transferred to a hospital. Treatment there consisted of the administration of medication and intensive observation. In the literature an intubation or the carrying out of a tracheotomy with possible surgical interventions is also described. The cause lay in damage to the lingual cortical plate of the mandible and trauma of the underlying vascular structures. Especially the cuspid and bicuspid regions are vulnerable because of the often seen lingual concavity in the processus alveolaris. Serious atrophy of the processus alveolaris is also a predisposition. To reduce the probability of such complications knowledge of the local anatomy, good clinical inspection and various radiographic evaluations are important. In case of obstruction of the trachea it is of vital importance to immediately transport the patient to the nearest hospital for further treatment.

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.