The cantilever contact-point resin bonded bridge; adhesion 2.0.

AIM: When young patients are congenitally missing anterior teeth, different treatment modalities can be used to complement the dental arch. This article proposes a new treatment modality for the replacement of anterior teeth, the cantilever contact-point resin bonded bridge (CCP-RBB). MATERIALS AND METHODS: In this proof of principle study, CCP-RBB's delivered by one operator were clinically assessed. Patients who were missing maxillary incisors and had suitable intra-oral conditions for a contact-point cantilever RBB were included. Three cases are presented to describe all adhesive steps. This proof of principle clinical study is presented with up to 60 months follow-up of the cantilever contact resin bonded bridges. RESULTS: A total of 19 CCP-RBB's were evaluated after a mean period of 29.8 months. None of the restorations exhibited failure, carious lesions or fractures during the follow-up periods, demonstrating an absence of restoration debonding or the need for repair. CONCLUSION: The new cantilever contact-point resin bonded bridge exhibited an excellent treatment modality without failure or debonding up to 5 years. More and extended duration in vivo studies are needed to evaluate this new treatment modality. CLINICAL SIGNIFICANCE: In this proof of principle the new cantilever contact-point resin bonded bridge obtained excellent results up to 5 years of clinical follow-up.

Effect of preparation design on fracture strength of compromised molars restored with direct composite resin restorations: An in vitro and finite element analysis study.

STATEMENT OF PROBLEM: More data are needed on the influence of preparation design on the fracture strength, failure type, repairability, and polymerization-induced cracks of molar teeth restored with direct composite resin restorations. PURPOSE: This in vitro and finite element analysis study investigated the effect of different preparation designs on fracture strength, failure type, repairability, tooth deformation, and the formation of polymerization-induced cracks of compromised molars restored with direct composite resin restorations. MATERIAL AND METHODS: Human molars (n=64) were randomly assigned to 4 different preparation designs: undermined inlay (UI), extended inlay (EI), restricted overlay (RO), and extended overlay (EO). The teeth were restored using direct composite resin and subjected to artificial thermomechanical aging in a mastication simulator, followed by load-to-failure testing. Three-dimensional (3D) finite element analysis was conducted to assess tooth deformation. Polymerization-induced cracks were evaluated using optical microscopy and transillumination. The fracture strength data were analyzed using a Kruskal-Wallis test, while the failure mode, repairability, and polymerization cracks were analyzed using the Fisher exact test (α=.05). RESULTS: All specimens withstood thermomechanical aging, and no statistically significant difference in fracture strength was observed among the 4 preparation designs (P>.05). The finite element analysis showed differences in tooth deformation, but no correlation was observed with in vitro fracture resistance. The RO and EO groups presented significantly more destructive failures compared with the UI and EI groups (P<.01). The RO group had significantly fewer repairable failures than the UI and EI groups (P=.024). A correlation was found between higher frequencies of repairability and higher tooth deformation. A significant correlation between the increase in microfractures and preparation design was observed (P<.01), with the UI group exhibiting a higher increase in microfracture size compared with the EO group (P<.05). CONCLUSIONS: No influence of preparation design on the fracture strength of compromised molars restored with direct composite resin restorations was evident in this study, but the failure mode of cusp coverage restorations was more destructive and often less repairable. The finite element analysis showed more tooth deformation in inlay preparations, with lower stresses within the root, leading to more reparable fractures. Since cusp coverage direct composite resin restorations fractured in a more destructive manner, this study suggests that even a tooth with undermined cusps should be restored without cusp coverage.

Clinical performance of direct composite resin versus indirect restorations on endodontically treated posterior teeth: A systematic review and meta-analysis.

STATEMENT OF PROBLEM: High-level evidence concerning the restoration of endodontically treated posterior teeth by means of direct composite resin or indirect restorations is lacking. PURPOSE: The purpose of this systematic review and meta-analysis was to analyze the current literature on the direct and indirect restoration of endodontically treated posterior teeth. MATERIAL AND METHODS: Databases MEDLINE, CENTRAL, and EMBASE were screened. Risk of bias was assessed by using the ROB2 tool for RCTs and the ROBINS-I tool for prospective and retrospective clinical studies. Randomized clinical trials (RCTs) and prospective and retrospective studies comparing direct composite resin and indirect restorations on endodontically treated posterior teeth were included. Outcomes were tooth and restoration survival. A meta-analysis was conducted for tooth retention and restorative success. RESULTS: Twenty-two studies were included (2 RCTs, 3 prospective, and 17 retrospective). Over the short term (2.5 to 3 years), low-quality evidence suggested no difference in tooth survival. For the prospective and retrospective clinical trials, the overall risk of bias was serious to critical from the risk of confounding because of a difference in restorative indication: Direct restorations were fabricated when one marginal ridge remained or when tooth prognosis was unfavorable. For short-term restorative success, low-quality evidence suggested no difference between the direct and indirect restorations. CONCLUSIONS: For the short term (2.5 to 3 years), low-quality evidence suggests no difference in tooth survival or restoration quality. To assess the influence of the type of restoration on the survival and restorative success of endodontically treated posterior teeth, clinical trials that control for the amount of coronal tooth tissue and other baseline characteristics are needed.

A 32-month evaluation of lithium disilicate cantilever resin-bonded fixed dental prostheses to replace a missing maxillary incisor.

STATEMENT OF PROBLEM: The absence of a tooth in the esthetic zone can cause emotional and social distress. The use of minimally invasive and visually pleasing lithium disilicate resin-bonded fixed dental prostheses (RBFDPs) may be a suitable option for replacing a missing maxillary incisor. However, the available literature on lithium disilicate cantilever RBFDPs is limited. PURPOSE: This retrospective multicenter study assessed the survival and success rates of lithium disilicate anterior cantilever RBFDPs with an average follow-up period of 3 years up to 9 years. MATERIAL AND METHODS: RBFDPs delivered by 3 operators were clinically assessed for survival using a modified United States Public Health Service criteria list. The incidence density was determined for each criterion and operator. The standard error and 95% confidence interval were calculated for each incidence density difference (α=.05 for all analyses). RESULTS: A total of 108 RBFDPs were evaluated after a mean period of 32.45 months, ranging from 14 days to 111 months. None of the restorations exhibited failure, carious lesions, or fractures during the follow-up period. The primary reasons for reduced success rates were inflammation of the surrounding soft tissues and discoloration, with incidence densities of 0.074 and 0.057 per year, respectively. Significant differences were observed among RBFDPs from different operators for criteria that included adaptation, color match, marginal adaptation, polishability, surface staining, gingival health, and antagonist wear. CONCLUSIONS: Cantilever lithium disilicate RBFDPs appear to be suitable for short-term restoration. RBFDPs exhibited visible changes after short-term follow-up. However, these changes did not result in failure.

Bilayered ceramic anterior restorations with reinforcement of the incisal edge by using lithium disilicate: A multicenter retrospective survival analysis with a maximum of 6-year follow-up.

STATEMENT OF PROBLEM: The esthetics of anterior lithium disilicate restorations can be enhanced if the buccal aspect is layered with a feldspathic ceramic. However, whether fractures and chipping of this layer are a prevalent complication is unclear. PURPOSE: The purpose of this retrospective study was to evaluate the incidence of incisal fracture of a specially designed lithium disilicate reinforcement of the incisal edge for indirect anterior bilayered restorations on both teeth and implants. MATERIAL AND METHODS: A total of 924 anterior bilayered pressed lithium disilicate restorations in 324 patients and made in one dental laboratory were delivered by 4 restorative dentists. The restorations had the palatal side of the incisal edge in monolithic lithium disilicate and the facial side in feldspathic porcelain. The restorations were evaluated for survival and the occurrence of fracture or chipping. Survival analyses were performed by using the Kaplan-Meier and log rank (Mantel-Cox) tests (α=.05). RESULTS: Of the 924 restorations, 798 (236 complete crowns, 562 partial restorations) were placed on teeth and 126 on implants. The mean observation time was 38 months (3 to 72 months). The survival rate was 96.5%, with 14 failures occurring. The failures were fracture after dental trauma (n=5), ceramic fracture (n=1), debonding (n=6), poor shade match (n=1), and tooth loss (n=2). Restorations in patients with parafunctional habits and endodontically treated teeth showed a significant decrease in survival rate (P=.018). No significant differences were found between the survival of restorations on teeth and implants and between complete crowns and partial restorations (P=.021). No chipping was observed on any restorations in the study. CONCLUSIONS: Modified anterior bilayered ceramic restorations showed good survival rates, and no chipping was observed up to 6 years of follow-up. Parafunctional habits and endodontic treatment had a negative effect on the survival rate of restorations. The support of tooth or implant and the restoration type had no effect on the survival.

Clinical report and fractographic analysis of a fractured partial laminate veneer.

Ceramic partial laminate veneers represent a conservative option for the correction of morphological abnormalities, diastemas, and fractured anterior teeth, with minimal or no tooth preparation. The present clinical report describes the use of a partial laminate veneer to correct the shape of a maxillary right central incisor to match the restoration of the more damaged adjacent tooth. The failure of the partial laminate veneer after only 18 months was analyzed using a systematic fractographic approach, identifying critical considerations that should be addressed when providing this type of restoration.

Prospective clinical evaluation of 765 partial glass-ceramic posterior restorations luted using photo-polymerized resin composite in conjunction with immediate dentin sealing.

OBJECTIVES: To evaluate the clinical performance of partial glass-ceramic (IPS e.max Press) posterior restorations. MATERIALS AND METHODS: A total of 765 restorations in 158 patients were placed between 2008 and 2018 and evaluated in a prospective study during regular dental care visits between 2015 and 2018. The restorations were luted with a conventional photo-polymerized resin composite (HFO) in conjunction with an Immediate Dentin Sealing procedure (IDS). Intra-oral photographs and radiographs were made and evaluated using USPHS criteria. RESULTS: The mean observation time was 53.3 months (range 3-113 months). Three absolute failures occurred (tooth fractures, n = 2; apical re-infection, n = 1) all leading to the loss of the restored tooth. Repairable and salvageable failures occurred in 9 teeth (endodontic complications, n = 7; secondary caries, n = 1; debonding, n = 1). The survival and success rates according to Kaplan-Meier after 5 years cumulated to 99.6% and 98.6%, respectively. Location (premolar/molar and mandibula/maxilla), pre-restorative endodontic status (vital/devitalised) and extension of the indirect ceramic restoration (number of sides and cusps involved) did not significantly affect the cumulative success rate (log rank test, p > 0.05). The condition of the vast majority of the restorations remained unaffected for 5 years. CONCLUSIONS: Partial glass-ceramic posterior restorations (pressed lithium disilicate (IPS e.max press, Ivoclar Vivadent) luted by means of a conventional photo-polymerized resin composite in conjunction with the use of an IDS procedure have an excellent medium-term prognosis. CLINICAL RELEVANCE: Partial glass-ceramic posterior restorations can be considered as a highly reliable treatment option. Location and extension of the restoration and pre-restorative endodontic status do not affect success rate.

Phase transformation and fracture load of stock and CAD/CAM-customized zirconia abutments after 1 year of clinical function.

OBJECTIVES: Functional loading and low-temperature degradation may give rise to impaired clinical long-term service of zirconia implant abutments. The aim of this study was to compare the fracture strength (primary outcome measure) and the volume percentage of monoclinic surface zirconia (m-ZrO2 ) of stock and CAD/CAM-customized zirconia implant abutments that functioned clinically for 1 year with geometrically identical pristine controls in an ex vivo experiment. MATERIAL AND METHODS: Twenty-three stock (ZirDesign™) and 23 CAD/CAM-customized (Atlantis™) zirconia implant abutments were retrieved after 1 year of clinical service. They were compared with pristine copies with respect to the volume fraction of the monoclinic phase using Raman spectroscopy and their fracture load by means of a single load-to-fracture test. Failure analysis was performed using optical and SEM microscopy. After verification of normal distribution, paired t tests were used for comparison of fracture loads between pristine and clinically aged specimen. All statistical tests employed a level of significance of α = 0.05. RESULTS: The fracture loads of the stock zirconia abutments were significantly (p < 0.05) reduced to 78.8% (SD 29.5%) after one year of clinical function. For the CAD/CAM abutments, no reduction in fracture load was found. No m-ZrO2 volume percentages beyond the detection threshold of 5% were observed in any of the samples. CONCLUSIONS: After 1 year of clinical service, no difference in fracture strength of the CAD/CAM-customized zirconia implant abutments could be demonstrated, whereas the stock zirconia abutments decreased considerably in fracture strength. No substantial tetragonal-to-monoclinic transformation was observed.

Esthetic Evaluation of Anterior Single-Tooth Implants with Different Abutment Designs-Patients' Satisfaction Compared to Dentists' Observations.

PURPOSE: To correlate patients' satisfaction and dentists' observations regarding two abutment designs used for single crowns in the esthetic zone: a divergent one (control) and a curved one (experimental), with special emphasis on muco-gingival esthetics. MATERIALS AND METHODS: Twenty-six patients with nonadjacent missing teeth in the esthetic zone were enrolled in a randomized clinical trial (within-subject comparison). Two implants placed in each were restored using abutments of different geometry. Patients' appreciation was assessed on a visual analog scale (VAS) by recording answers to three questions, and dentists' appreciation was determined by means of the Pink Esthetic Score (PES) at T0 (crown cementation, baseline) and at T12 (1 year post-cementation). ANOVA with post hoc analysis was used to identify differences between groups and at different moments in time. Pearson correlations were calculated between all variables, both at T0 and at T12. RESULTS: No statistically significant differences were found at any time between the control and experimental abutment design, either for the PES or for the VAS score. PES slightly improved after 1 year, as did the VAS rating related to functioning with the implant-crown compared to the natural teeth. All PES and VAS scores demonstrated highly significant correlation. Both patient satisfaction and professional appreciation of muco-gingival conditions after single implant treatment in the esthetic zone were high; however, the curved, experimental abutment design performed no better than the conventional, divergent type. CONCLUSION: Curved abutment design does not significantly impact crown or gingival esthetics as assessed by PES and VAS scored by dentists and patients, respectively.

Ceramic partial laminate veneers in anterior teeth: A literature review.

STUDY SELECTION: Partial laminate veneers, defined as small ceramic restorations adhesively luted onto unprepared anterior teeth, are an interesting and conservative alternative to conventional ceramic and composite resin veneers in the anterior region. This literature review aimed to summarize the available laboratory and clinical data on ceramic partial laminate veneers. An electronic search of the MEDLINE/PubMed, EBSCO, and Web of Science databases was conducted. The keywords used were "partial veneer," "partial laminate veneer," "ceramic fragment," and "sectional veneer." The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. The risk of bias in the included studies was assessed using the QUIN tool. RESULTS: Of the 266 identified articles, only 16 met the inclusion criteria (ten clinical reports, five laboratory studies, and one retrospective clinical study). To date, no randomized controlled clinical trials have been conducted. Most laboratory studies displayed a low risk of bias, with partial laminate veneers rendering adequate strength and color stability. Clinical reports have shown large variability in material selection, luting, and finishing/polishing protocols. CONCLUSIONS: Low-quality evidence is available for ceramic partial laminate veneers. Available data from laboratory studies suggest good mechanical and optical performances comparable to those of conventional ceramic and composite resin veneers. Further clinical studies with longer follow-up periods are warranted.

Biomechanical behavior of molars restored with direct and indirect restorations in combination with deep margin elevation.

STATEMENT OF PROBLEM: The existing knowledge is insufficient for comprehending the fatigue survival and fracture resistance of molars that have deep approximal direct and indirect restorations, whether with or without deep margin elevation (DME). PURPOSE: The aim of this laboratory and in silico study is to investigate the fatigue survival, fracture strength, failure pattern and tooth deformation of molars restored with DME in combination with a direct or indirect restoration. MATERIAL AND METHODS: This study utilized 45 extracted sound human molars, divided into three groups (n = 15). Standardized 100% inter-cuspal inlay preparations were performed, extending 2 mm below the CEJ and immediate dentin sealing (IDS) was applied. Group 1 (Co_1) was restored with direct composite; Group 2 (Hyb_2) with a 2 mm DME of direct composite and a glass-ceramic lithium disilicate restoration; Group 3 (Cer_3) a glass-ceramic lithium disilicate restoration. All specimens were exposed to a fatigue process involving thermal-cyclic loading (50N for 1.2 × 106 cycles at 1.7 Hz, between 5 and 55 °C), if teeth survived, they were fractured using a load-to-failure test and failure types were analyzed. Finite element analysis (FEA) was conducted to assess tooth deformation and tensile stress in the restorations. Statistical evaluation of fracture strength was conducted using the Kruskal-Wallis test. Fisher's exact test was utilized to analyze the fracture types and repairability. A statistical significance level of α < 0.05 was set for all analyses. RESULTS: All specimens successfully withstood the fatigue testing procedure, and no statistically significant differences in fracture strength were observed among the three groups (P > 0.05). The Fisher's exact test indicated a significant association between the restorative material and fracture type (F2 = 18.315, df = 2, P = 0.004), but also for repairability (F2 = 13.725, df = 2, P = 0.001). Crown-root fractures were significantly more common in the Cer_3 group compared to the Co_1 group (P = 0.001) and the Co_1 group had significantly more repairable fractures (F2 = 13.197, df = 2, P = 0.001). FEA revealed comparable outcomes of deformation among models and higher maximum tensile stress on models with higher frequency of catastrophic failures. CONCLUSIONS: All tested restoration materials exhibited comparable fatigue survival and fracture strength in this laboratory and in silico study. However, it is important to recognize the potential for more severe and irreparable fractures when opting for deeply luted glass-ceramic inlay restorations in clinical practice. In such cases, it would be prudent to consider the alternative option being a direct composite approach, because of its more forgiving fracture types and repairability. CLINICAL IMPLICATIONS: Molars with deep approximal direct and indirect restorations, whether with or without DME, are comparable in their fatigue survival and fracture resistance to withstand intra-oral forces. Deep direct restorations exhibit more repairable fractures compared to deeply luted glass-ceramics.

Partial glass-ceramic posterior restorations with margins beyond or above the cemento-enamel junction: An observational retrospective clinical study.

PURPOSE: This observational retrospective clinical study aimed to investigate the survival and success rates of partial indirect lithium disilicate restorations with margins extending above or beyond the cementoenamel junction (CEJ). METHODS: The study included patients who underwent partial indirect lithium disilicate restorations with immediate dentin sealing (IDS) between January 2008 and October 2018. All the restorations were placed in a single general dental practice following a standardized protocol. The impact of various predictive variables on the survival rates was assessed. Moreover, modified United States Public Health Service (USPHS) criteria were used to evaluate the survival quality. RESULTS: Totally 1146 partial indirect lithium disilicate restorations in 260 patients were evaluated over an average period of 7.5 years. The cumulative survival and success rates were 97.3% and 95.3%, respectively. Margins extending beyond the cemento-enamel junction did not increase the risk of success or survival failure (P > 0.05). Patients with a high risk of caries, male sex, or non-vital teeth had a significantly higher risk of restoration failure (P < 0.05). Restorations with longer clinical service times exhibited marginally lower clinical quality (P < 0.001). CONCLUSIONS: Partial indirect glass-ceramic restorations demonstrated survival and success rates of 97.3% and 95.3%, respectively, over an extended period. However, a higher risk of restoration failure existed in patients with a high caries risk for (pre)molars that had undergone endodontic treatment and in males. In terms of the risk of success or survival failure, comparable results were obtained for the positions of the restoration margin in relation to the cemento-enamel junction.

Clinical longevity of ceramic laminate veneers bonded to teeth with and without existing composite restorations up to 40 months.

OBJECTIVES: This study evaluated the survival rate of ceramic laminate veneers bonded to teeth with and without existing composite restorations (ECR). MATERIALS AND METHODS: Twenty patients (mean age: 49.7 years) received 92 feldspathic ceramic laminate veneers (Shofu Vintage AL) on the maxillary teeth (intact teeth: n = 26; teeth with ECR: n = 66). Preparations with incisal overlap were made, and ECR of good quality were not removed but conditioned using silica coating (CoJet) and silanization (ESPE-Sil). Enamel and dentin were etched with 38% H3PO4 for 15-30 s and rinsed 30 s; adhesive resin (Excite) was applied, and laminate veneers were then cemented (Variolink Veneer). Restorations were evaluated at baseline and thereafter every 6 months using modified United States Public Health Service criteria. RESULTS: Mean observation period was 21.6 months. Overall, five absolute failures were encountered (fractures: n = 3; chipping: n = 1; debonding: n = 1), resulting in a survival rate of 94.6% (Kaplan-Meier). Survival rates of the laminates bonded to teeth without (96%) and with ECR (93.5%) did not show significant differences (p > 0.05). Slight marginal defects (16 of 87 laminates) and slight marginal discoloration at the margins were noted (12 of 87 laminates) until the final recall. Secondary caries and endodontic complications were not detected in any of the teeth. CONCLUSION: The clinical survival of ceramic laminate veneers up to 40 months was not significantly influenced when they were bonded onto intact teeth or onto teeth with ECR. CLINICAL RELEVANCE: When no caries is present, it may not be necessary to replace existing composite restorations prior to cementation of ceramic laminate veneers.

Effect of preparation design on fracture strength of compromised molars restored with lithium disilicate inlay and overlay restorations: An in vitro and in silico study.

PURPOSE: The objective of this study was to determine the influence of different preparation designs on the fracture strength, failure type, repairability, formation of polymerization-induced cracks, and tooth deformation of structurally compromised molars restored with lithium disilicate inlays and overlays in combination with Immediate Dentin Sealing (IDS). MATERIAL AND METHODS: Human molars (N = 64) were randomly assigned to four different preparation designs: Undermined Inlay (UI), Extended Inlay (EI), Restricted Overlay (RO), and Extended Overlay (EO). The teeth were restored using lithium disilicate partial restorations and subjected to thermomechanical fatigue in a chewing simulator (1,2 × 10 (Mondelli et al., 2007) cycles on 50 N, 8000x 5-55 °C), followed by load to failure testing. In silico finite element analysis was conducted to assess tooth deformation. Polymerization-induced cracks were evaluated using optical microscopy and transillumination. Fracture strengths were statistically analyzed using a Kruskal-Wallis test, while the failure mode, repairability, and polymerization cracks were analyzed using Fisher exact test. RESULTS: The propagation of polymerization-induced cracks did not significantly differ among preparation designs. All specimens withstood chewing simulator fatigue, with no visible cracks in teeth or restorations. Fracture strength was significantly influenced by preparation design, with restricted overlay (RO) showing higher fracture strength compared to extended inlay (EI) (p = .042). Tooth deformation and fracture resistance correlated between in vitro and in silico analyses). UI exhibited a statistically less destructive failure pattern than EO (p < .01) and RO (p = .036). No statistically significant influence of the preparation design on repairability was observed. Groups with higher repairability rates experienced increased tooth deformation, leading to less catastrophic failures. CONCLUSIONS: The preparation design affected the fracture strength of compromised molars restored with lithium disilicate inlays and overlays, with significantly lower fracture strength for an extended inlay. The failure pattern of lithium disilicate overlays is significantly more destructive than that of undermined and extended inlays. The finite element analysis showed more tooth deformation in the inlay restorations, with lower forces in the roots, leading to less destructive fractures. Since cusp coverage restorations fracture in a more destructive manner, this study suggests the undermined inlay preparation design as a viable option for restoring weakened cusps.

Clinical longevity of extensive direct resin composite restorations after amalgam replacement with a mean follow-up of 15 years.

OBJECTIVES: The aim of this retrospective clinical study was to determine the survival of extensive direct resin composite restorations after amalgam replacement on vital molars and premolars after a mean observation period of 15 years. METHODS: Between January 2007 and September 2013, a total of 117 extensive cusp replacing direct resin composite restorations were placed in 88 patients in a general dental practice. These were indicated for replacement of existing amalgam restorations. Tooth vitality, the absence of at least one cusp in premolars, and at least two cusps in molars were considered for inclusion. The long-term follow-up of the restorations, re-evaluated after up to 17 years using the original evaluation criteria is reported. RESULTS: 81 of 88 patients (92.1%) and 106 of 117 restorations (90.6%) were available for follow-up. The cumulative success rate was 62.0% (95% CI: 47.3-76.2, AFR 2.79%) after a mean observation time of 163.4 months, the cumulative survival rate was 74.7% (95% CI: 59.8-89.6%, AFR: 1.70%) after a mean observation time of 179.1 months. The number of cusps replaced in premolars had a statistically significant influence on the success and survival rate of the restorations (HR of respectively, 2.974 and 3.175, p = <0.0005). Premolars with two cusps replaced had 297% more chance of failure than premolars with one cusp replaced. CONCLUSIONS: Extensive direct resin composite restorations placed after amalgam replacement showed good survival after a mean observation period of 15 years. The number of cusps involved had a statistically significant influence on the longevity of the restorations in premolars. CLINICAL SIGNIFICANCE: With good survival and low annual failure rates, direct resin composite restorations are a suitable treatment for repairing extensive defects in posterior teeth involving multiple cusps and surfaces, provided that they are placed by a dentist who has long experience and is skilled in the placement of direct composite materials.

Deep margin elevation.

Deep subgingival margins are a much-debated topic in adhesive and restorative dentistry. The hydrophobic trait of direct composite resin materials challenges the restorative procedure of cavities with deep subgingival margins since isolation is complicated. A correct indication for a deep margin elevation (DME) treatment is the key to its clinical success, and adequate adaptation of the DME is crucial to its clinical performance. An adequate adaptation of the DME may potentially reduce bacterial accumulation and reduce the incidence of secondary caries as well as maintain periodontal health. The present case report aims to provide a step-by-step overview of the DME technique when applied in combination with a partial indirect glass-ceramic restoration and also provides clinical guidelines to tackle deep subgingival cavities. The indication for a DME and the selection of appropriate materials are explained, supported by the literature.

Increasing Acid Concentration, Time and Using a Two-Part Silane Potentiates Bond Strength of Lithium Disilicate-Reinforced Glass Ceramic to Resin Composite: An Exploratory Laboratory Study.

There is still a lack of consensus concerning the recommended etching concentration, application time and type of silane when bonding lithium disilicate-reinforced glass ceramics manufactured by CAD/CAM. The purpose of this study was thus to conduct an in vitro study which investigates the influence of hydrofluoric acid (HF) concentration, etching time and silane type on the microtensile bond strength (µTBS) of lithium disilicate to resin composites. Thirty-nine IPS e.max CAD blocks were randomly divided between thirteen groups (n = 3). The variables were HF concentration (9.5 or 4.9%), etching time (20 or 60 s) and silane type (Bis-Silane, Monobond Plus and ESPE Sil Silane). The blocks were cut into beams, aged for 10,000 cycles in a thermocycler and submitted to tensile stress to determine µTBS. A control group featuring the Monobond Etch & Prime (MEP) agent that combines etching/silanisation into a simultaneous process was also added. This group was discarded from the analysis due to only having pre-test failures. The data were analysed using a three-way ANOVA (α = 0.05). The HF concentration, etching time and silane type significantly influenced µTBS (p < 0.001). Significant interactions between time and silane type (p = 0.004), HF concentration and silane type (p < 0.001) and among the three factors (p < 0.001) were noted. Etching lithium disilicate with 9.5% HF (60 s), followed by the application of Bis-Silane, resulted in the highest µTBS (16.6 ± 9.0 MPa). The highest concentration and etching time under study, combined with a two-part silane, resulted in the highest bond strength, while the application of MEP showed a complete pre-test failure.

Partial anterior indirect restorations in cases with dentin exposure.

The partial anterior ceramic restoration is a predictable and durable treatment modality that reestablishes not only esthetics but also strength and function. Bio-emulation, minimally invasive dentistry, and adhesive technology are key to a successful restoration. Partial restorations are only indicated when teeth have enough hard tissue on which to bond veneers. When there is more than 50% of dentin exposure, many clinicians still rely on macromechanical retention by performing a full-crown preparation. However, new research has shown good survival rates for partial restorations with extensive dentin exposure. The present article describes two cases in which a step-by-step protocol was applied to bond a laminate veneer to a tooth with dentin exposure.

Influence of the ceramic translucency on the relative degree of conversion of a direct composite and dual-curing resin cement through lithium disilicate onlays and endocrowns.

INTRODUCTION: The goal of this study was to investigate the influence of the ceramic translucency, restoration type and polymerization time on the relative degree of conversion of a dual-curing resin cement and a conventional microhybrid resin composite using a high-power light-curing device. METHODS AND MATERIALS: Two 4.0 mm thick onlay (O) and two 7.5 mm thick endocrown (E) lithium disilicate restorations in high and low translucency (HT/LT) were fabricated on a decapitated molar. The pulp chamber was prepared to accommodate a 2 mm layer of a microhybrid resin composite (MHC) or dual-curing resin cement (DCC). Composite specimens were light-cured (n = 15; 1200 mW/cm2) without or through an onlay or endocrown restoration. Fourier-transform infrared spectroscopy (FTIR) absorbance curves were collected for the same composite specimen after 3 × 20, 3 × 40, 3 × 60 and 3 × 90 s of light-curing. The relative degree of conversion (DC%) was calculated and results analyzed using Kruskal-Wallis test and Friedman's ANOVA. Alpha was set at 0.05. RESULTS: After 3 × 60 s, the DC of MHC was significantly lower (p = 0.03; r = 0.61) under LT/EC restorations (Mdn: 77.8%) than HT/EC restorations (Mdn: 95.2%). DC of the DCC was not significantly affected by the ceramic translucency or restoration type. MHC had a significant higher DC than DCC under the HT/O, LT/O and HT/E restorations. There were no significant differences between MHC and DCC cured through LT/E restorations. CONCLUSION: DC for DCC was not significantly affected by the ceramic translucency or restoration type. DC for MHC was significantly lower for LT/EC than HT/EC restorations after 3 × 60s polymerization, but not different for the high translucent restorations and low translucent onlays. CLINICAL RELEVANCE: the use of light-curing microhybrid composite for bonding high translucent onlays and endocrowns and low translucent onlays seems feasible.

Comparison of conventional ceramic laminate veneers, partial laminate veneers and direct composite resin restorations in fracture strength after aging.

OBJECTIVES: The objectives of this study were to test the fracture strength in vitro of laminate veneers, partial laminate veneers and composite restorations after aging and analyze the failure mode. METHODS: Forty extracted, sound human teeth were selected and divided into four groups: 1) Control group (CG); 2) Conventional Laminate Veneer (CLV); 3) Partial Laminate Veneer (PLV); 4) Direct Composite Resin (DCR). Laminate veneer preparations with incisal overlap were made in group CLV whereas only incisal preparations were made with a 1 mm bevel in group PLV and DCR. The indirect restorations were luted with a resin composite and the DCR group was restored with a direct resin composite restoration. The restored teeth were subsequently aged by thermocycling (20.000 cycles, 5-55 degrees C). Subsequently, the fracture strength was tested by a load to failure test at 135° on the incisal edge. A failure analysis was performed using light microscopy. The results were analyzed using Shapiro-Wilk and Kruska-Wallis test. RESULTS: After thermocycling, one sample from group CLV presented a premature adhesive failure and was excluded. Three restorations from groups PLV and DCR presented small cracks but were taken to the fracture test. After aging mean fracture load + SD (N) were: Group DCR (n = 10): 385 ± 225; Group CG (n = 10): 271 ± 100; Group PLV (n = 10): 266 ± 69; Group CLV (n = 9): 264 ± 66. Fracture strength means from groups CLV and PLV did not differ statistically from each other nor from control (p = 0.05). In the group CLV the root fracture was the most occurring fracture. In groups PLV and DCR, material cohesive failures and a mix (adhesive, tooth and material cohesive) failures were most observed. SIGNIFICANCE: This in vitro study showed for the first time that partial laminate veneers can exhibit fracture strength values similar to direct composite restorations or conventional ceramic laminate veneers. All three restorative procedures presented clinically acceptable values of fracture strength. Even though three samples from groups PLV and three from DCR presented small cracks after thermocycling, these cracks do not appear to have a negative effect on the fracture strength.