Partial Coverage Restorations Research Articles

Fracture resistance of chairside CAD-CAM lithium disilicate occlusal veneer with various designs after mechanical aging.

This study evaluated the fracture resistance of chairside computer-aided design and computer-aided manufacturing (CAD-CAM) lithium disilicate crown, onlay, and non-anatomical occlusal veneer (A-OV) with and without margin fabricated. Sixty-four CAD-CAM lithium disilicate restorations were designed as (1) complete coverage crown (CCC); (2) A-OV with margin; (3) non-A-OV with margin (NA-OV-M); and (4) non-A-OV without margin (NA-OV-NM), 16 of each. Restorations were crystallized and adhesively luted to resin dies using resin cement. Specimens were then subjected to 400,000 cycles of chewing in a mastication simulator. A universal testing machine was used to apply a compressive load at a crosshead speed of 1mm/min to the long axis of the tooth with a stainless-steel sphere until fracture occurred. One-way ANOVA followed by post hoc tests were used to assess the impact of preparation design on the fracture load of CAD-CAM lithium disilicate restorations. The highest fracture load was recorded for CAD-CAM lithium disilicate indirect restorations for non-A-OVs preparation with margin (2549±428 N) and onlay (2549±293 N) and the lowest fracture load was recorded for CCCs (2389±428 N); however, there was no significant (p = 0.640) between groups. CAD-CAM lithium disilicate restorations fabricated for anatomical and non-A-OV preparation display a fracture resistance similar to CCCs. Conservative partial coverage restorations may be considered an acceptable approach for posterior teeth.

3D-printed intracoronal restorations, occlusal and laminate veneers: Clinical relevance, properties, and behavior compared to milled restorations; a systematic review and meta-analysis.

To assess the feasibility of producing 3D-printed intracoronal restorations, thin and ultrathin veneers, and to compare their mechanical behavior, accuracy, biological, and stain susceptibility to the currently applied milled restorations. The databases were comprehensively searched for relevant records up to January 2024 without language restrictions. All studies that assessed 3D-printed partial coverage restorations including inlays, onlays, laminate, and occlusal veneers were retrieved. The web search yielded a total of 1142 records, with 8 additional records added from websites at a later stage. Only 17 records were ultimately included in the review. The included records compared 3D-printed; alumina-based- and zirconia ceramics, lithium disilicate ceramics, polymer infiltrated ceramics, polyetheretherketone (PEEK), resin composites, and acrylic resins to their CNC milled analogs. The pooled data indicated that it is possible to produce ultrathin restorations with a thickness of less than 0.2 mm. 3D-printed laminate veneers and intracoronal restorations exhibited superior trueness, as well as better marginal and internal fit compared to milled restorations (p < 0.05). However, it should be noted that the choice of materials and preparation design may influence these outcomes. In terms of cost, the initial investment and production expenses associated with 3D printing were significantly lower than those of CNC milling technology. Additionally, 3D printing was also shown to be more time-efficient. Using additive manufacturing technology to produce restorations with a thickness ranging from 0.1 to 0.2 mm is indeed feasible. The high accuracy of these restorations, contributes to their ability to resist caries progression, surpassing the minimum clinical threshold load of failure by a significant margin and reliable adhesion. However, before 3D-printed resin restorations can be widely adopted for clinical applications, further improvements are needed, particularly in terms of reducing their susceptibility to stains. 3D-printed intracoronal restorations and veneers are more time and cost-efficient, more accurate, and could provide a considerable alternative to the currently applied CNC milling. Some limitations still accompany the resin materials, but this could be overcome by further development of the materials and printing technology.

Minimally invasive CAD/CAM lithium disilicate partial-coverage restorations show superior in-vitro fatigue performance than single crowns.

To analyze the influence of restoration design (partial-coverage restoration vs. crown) and ceramic layer thickness on the performance and failure loads of CAD/CAM-fabricated lithium disilicate (LDS) reconstructions on molars after fatigue. Seventy-two posterior monolithic CAD/CAM-fabricated LDS restorations (IPS e.max CAD, Ivoclar Vivadent) with different occlusal/buccal ceramic layer thicknesses (1.5/0.8, 1.0/0.6, and 0.5/0.4 mm) and restoration designs (PCR: non-retentive full-veneer/partial-coverage restoration, C: crown,) were investigated and divided into six groups (n = 12, test: PCR-1.5, PCR-1.0, PCR-0.5; control: C-1.5, C-1.0, C-0.5). LDS restorations were adhesively bonded (Variolink Esthetic DC, Ivoclar Vivadent) to dentin-analogue composite dies (Z100, 3M ESPE). All specimens were subjected to thermomechanical loading (1.2 million cycles, 49 N, 1.6 Hz, 5-55°C) and exposed to single load to failure testing. Failure analysis was performed with light and scanning electron microscopies. Data were statistically analyzed using ANOVA, Tukey-Test, and t-test (p < 0.05). Eight crown samples (C-0.5) and one PCR specimen (PCR-0.5) revealed cracks after fatigue, resulting in an overall success rate of 87.5% (crowns: 75%, PCRs: 96.88%). Direct comparisons of PCRs versus crowns for thicknesses of 0.5 mm (p < 0.001) and 1.0 mm (p = 0.004) were significant and in favor of PCRs. Minimally invasive PCRs (0.5 and 1.0 mm) outperformed crowns with the identical ceramic thickness. No difference was detected (p = 0.276) between thickness 1.5 mm PCRs and crowns. Minimally invasive monolithic CAD/CAM-fabricated posterior LDS PCRs (0.5 and 1.0 mm) resulted in superior failure load values compared to minimally invasive crowns. Minimally invasive crowns (0.5 mm) are prone to cracks after fatigue. Minimally invasive CAD/CAM-fabricated LDS PCR restorations with a non-retentive preparation design should be considered over single crowns for molar rehabilitation.

An 8-year retrospective study of fixed prosthodontics clinical unit completions in a postgraduate prosthodontics program.

The range of aesthetic fixed prosthodontics materials utilizing digital manufacturing techniques has expanded in recent years ostensibly replacing traditional laboratory techniques and materials. This retrospective study conducted over eight consecutive years aimed to analyze the types of laboratory fabricated fixed prosthodontics clinical units completed in a postgraduate prosthodontics specialist training program and determine meaningful trends. The logbooks of eight postgraduate prosthodontics completions from 2014 to 2021 were reviewed and the different types of laboratory fabricated fixed prosthodontics units and total number of fixed prosthodontics units completed were recorded. The data was categorized and presented in tabulated and chart form using Microsoft Excel software (version 2016). Paired t-tests and Mann-Kendall trend tests were performed to analyze for statistical significance between the different restoration types across the program completions. Porcelain bonded to metal (PBM) crowns represented 42.05% of all fixed prosthodontics units completed over all study years followed by all-ceramic crowns (ACC) (18.14%) and full gold crowns (FGC) (10.70%). Jointly, PBM, ACC and FGC's encompassed 70.88% of all fixed prosthodontics units. Over the 8-year study period, there were observed trends of reduced use of PBM's, increased use of ACC's, statistically significant reduced use of FGC's (p = 0.035) and a statistically significant difference in the use of complete and partial coverage restorations (p < 0.001). PBM crowns were the dominant laboratory fabricated fixed prosthodontic clinical unit across postgraduate prosthodontics program completions. The trend in later years indicating ACC as the dominant crown type warrants further investigation.

Conservative approach for rehabilitation of anterior esthetic zone

Partial coverage restorations have been used in Prosthodontic practice with variable success rates. Resin Bonded Restorations have been used successfully since 1973. With modifications in design of prosthesis, the need for preparation and with advancements in adhesive technology, the success rate has improved drastically. This treatment option is technique sensitive, but it conserves the natural tooth structure and provides desirable esthetic outcome. Proper case selection and treatment planning is utmost important for execution and success of resin bonded restorations.

General Consideration of Post Systems

More often than not pulpless teeth remain relatively intact after conservative endodontic treatment. Although it hasn't been shown that endodontically treated teeth are more brittle than healthy ones, pulpless teeth are known to crack during mastication. As a result of this known phenomenon, dental professionals have been looking for strategies to prevent pulpless teeth from breaking. Restoration and reinforcement of pulpless teeth is a crucial preventative step in endodontic therapy. A post is cemented into the root canal to reinforce a healthy endodontically treated tooth. The post is supposed to reinforce the tooth and keep it from breaking. A widely used technique for repairing teeth that have undergone endodontic treatment is post and cores. Retention applied onto the root thorough final restoration using the post and core restoration as a substructure. Therefore, post placement in the root is crucial. In order to ensure retention for a fixed restoration, endodontically treated teeth are frequently treated with posts and cores. Teeth that had gone through endodontic treatment often suffer from severe coronal damage. In order to ensure retention for full or partial coverage restoration, these teeth may require a coronal substructure or core for retention of a full or partial bonding restoration. Generally, primary retention feature of a core is an intraradicular post. Posts and cores are routinely used for endodontical teeth restoration. This article provides a review presentation about utilization of post systems on the pulpless tooth.

Tensile Bond Strength and Retention of Three Types of Ceramic Endocrowns.

By development of adhesive dentistry and noble mechanical strength of ceramics, reconstruction of posterior teeth with partial coverage restorations such as ceramic endocrowns is possible. Different ceramics may show different mechanical properties which should be investigated. The aim of this experimental in vitro study was to compare the tensile bond strength of endocrowns made by CAD-CAM using 3 types of ceramics. In this in vitro study, 30 fresh extracted human molars were prepared to evaluate the tensile bond strength of endocrowns made by IPS e.max CAD, Vita Suprinity, and Vita Enamic blocks (n=10). The specimens were mounted and endodontically treated. Standard preparations were done with 4.5±0.5 mm intracoronal extensions into the pulp chamber and the restorations were designed and milled by CAD-CAM technique. All specimens were cemented with a dual polymerizing resin cement according to the manufacturer's instructions. The specimens were incubated for 24 hours and then thermocycled for 5000 cycles at 5-55°C and underwent the tensile strength test by universal testing machine (UTM). Shapiro-Wilk and one-way ANOVA test were used to statistically analyzed (α= 0.05). The highest tensile bond strength values were achieved in IPS e.max CAD (216.39 ±22.67N) and Vita Enamic (216.22±17.72N) followed by Vita Suprinity (211.54±20.01N). There was no significant statistical difference between retention of endocrowns made by CAD-CAM technique among ceramic blocks (p= 0.832). Within the limitation of this study, there was no significant difference between retention of endocrowns made by IPS e.max CAD, Vita Enamic, and Vita Suprinity as ceramic blocks.

Digitally designed and additively manufactured tooth reduction guides for porcelain laminate veneer preparations: A clinical report

Porcelain laminate veneers are a conservative treatment to enhance esthetics, tooth shape, color, and contours. Enamel preservation during tooth preparation is essential for the long-term success of these micromechanically retained partial coverage restorations. Different methods have been described to clinically assess tooth preparation relative to definitive restorative contours. This clinical report describes a digital workflow to fabricate 3-dimensionally (3D) printed tooth reduction guides based on digital esthetic planning. These 3D printed reduction guides help clinicians visualize and gauge tooth preparations relative to the desired restorative contours, aid in enamel preservation, and overcome some of the limitations associated with conventionally fabricated tooth reduction guides.

Clinical performance of CAD-CAM partial-coverage restorations: Experienced versus less-experienced operators

Statement of problemLess-experienced operators have been shown to require additional training to achieve results similar to those of experienced operators. However, clinical data comparing the survival and success of ceramic restorations by experienced and less-experienced operators by using the computer-aided design and computer-aided manufacturing (CAD-CAM) technology are lacking. PurposeThe purpose of this retrospective clinical study was to analyze and compare the clinical performance of CAD-CAM lithium disilicate restorations fabricated by less-experienced (predoctoral dental students) and experienced (dentists) operators. Material and methodsPatients who received an adhesively luted CAD-CAM lithium disilicate restoration between 2011 and 2019 were included in the study. Clinical performance was assessed by calibrated examiners by using World Dental Federation (FDI) criteria. Success and survival were calculated by the Kaplan-Meier method and statistically compared by log-rank tests and univariate Cox regression analyses. FDI criteria were compared by using Mann-Whitney-U tests (α=.05). ResultsNinety-two restorations (students: n=65, dentists: n=27) were assessed (mean ±standard deviation time from insertion: 4.04 ±1.55 years). The survival rates after 2 years (students: 93.8%, mean annual failure rate [mAFR]: 3.1%; dentist: 96.3%, mAFR: 1.9%) and after 4 years (students: 87.3%, mAFR: 3.3%; dentists: 88.3%, mAFR: 3.1%) were not significantly different (P=.525). Also, success rates after 2 (students: 90.8%, mAFR: 4.7%; dentists: 92.6%, mAFR: 3.8%) and 4 years (students: 82.4%, mAFR: 4.7%; dentists: 76.1%, mAFR: 6.6%) were not significantly different (P=.778). FDI criteria were also not significantly different between less-experienced and experienced operators (P≥.110). ConclusionsOperator experience did not affect the short-term clinical performance of CAD-CAM lithium disilicate restorations.

Incidence of endodontic therapy after complete or partial coverage glass-ceramic restorations with a follow-up time of over 30 years: A prospective clinical study

Statement of problemLong-term clinical data are lacking on the comparison of the incidence of endodontic therapy in adhesively luted complete and partial coverage glass-ceramic restorations, as well as on the effect of technique and clinical variables. PurposeThe purpose of this prospective clinical study was to assess the long-term incidence of teeth requiring endodontic therapy after receiving either complete or partial coverage glass-ceramic restorations. Material and methodsParticipants requiring single anterior complete, posterior complete, or posterior partial (inlay or onlay) coverage restoration, or a combination of these on a vital tooth were recruited from a clinical private practice. Only the participants who chose glass-ceramic partial and complete coverage restorations without the need of endodontic therapy were included in the study. The overall clinical performance of these glass-ceramic restorations was assessed by clinical factors determined at recall. The effect of various clinical parameters (type of restoration, dental arch, tooth position in the dental arch, age and sex of participant, and ceramic thickness) was evaluated by using Kaplan–Meier survival curves to account for attrition bias and other reasons for failure. The statistical significance of differences between parameters was determined by using the log rank test (α=.05). ResultsA total of 1800 participants requiring 4511 glass-ceramic anterior and posterior restorations were evaluated. The mean age of the participants at the time of restoration placement was 62 (range 20 to 99 years, 710 men and 1090 women). Of 4511 restorations, 1476 were anterior complete coverage, 2119 posterior complete coverage, and 916 posterior partial coverage. Endodontic therapy after restoration placement was needed for 76 restorations (10 anterior complete, 50 posterior complete, and 16 posterior partial). The total time at risk was 50 436 years providing an estimated need for endodontic therapy risk of 0.15% per year. The estimated 35-year cumulative survival was 97.36%. The majority of endodontic treatments (67%, 52/76) occurred in the first 5 years.The estimated cumulative survival of anterior complete coverage, posterior complete coverage, posterior partial inlay, and posterior partial onlay restorations was 98.89% (n=1476, 10 endodontic treatments), 96.38% (n=2119, 50 endodontic treatments), 96.78% (n=553, 11 endodontic treatments), and 98.53% (n=363, 5 endodontic treatments), respectively. Statistically significant differences occurred between anterior complete coverage, posterior complete coverage, and posterior partial coverage inlay restorations, with a higher incidence in posterior complete coverage and posterior partial inlay restorations (P<.05). First molars had the highest rate of endodontic therapy after restoration in both arches. Age and restoration thickness were significant factors, recording statistically higher number of endodontic treatments in participants >52 years and restorations with all surfaces ≥1 mm (P<.05). Other clinical variables, dental arch and sex of the participants, were not significantly related to endodontic treatments (P>.05). ConclusionsThe clinical performance of 4511 units over 30 years in service was excellent, with the estimated cumulative survival of 97.36%. Posterior complete coverage and posterior partial inlay restorations had a significantly higher need for endodontic therapy than anterior complete coverage restorations. Their overall clinical performance relative to endodontic treatment was excellent with a cumulative survival of 96.38% and 96.78% over 30 years. There was no difference in the endodontic treatment rate between posterior complete and partial coverage restorations. Thickness of the restoration affected the endodontic treatment rate, with ≥1 mm resulting in higher incidence. The age of the participants influenced the endodontic treatment rate, with higher incidence in the >52-year age group. Other confounding clinical variables did not have a significant effect on the endodontic treatment rate.

Fixed prosthodontics clinical unit completions in an undergraduate curriculum: A 10-year retrospective study.

Providing undergraduate dental students with a range of clinical experiences in fixed prosthodontics procedures is an important component of dental education. The aim of this retrospective study was to analyse the types of laboratory-fabricated fixed prosthodontics clinical units completed by undergraduate students over 10 consecutive years and determine any significant trends. The fixed prosthodontics treatment registers from 2012 to 2021 were reviewed and the different types of completed fixed prosthodontics units and total number of fixed prosthodontics units were recorded for each year. Completed units were categorised according to the type of restoration and expressed in whole numbers and as a percentage of the total number of units completed in each year. The data were presented in table and graph form. Mann-Kendall tests were performed to statistically analyse for trends in the different restoration types. Throughout all study years, porcelain bonded to metal (PBM) crowns (48.25%, range 35.70%-59.91%) were the most frequently completed fixed prosthodontics unit followed by full gold crowns (FGC) (20.84%, range 14.89%-27.30%) and all-ceramic crowns (ACC) (12.70%, range 3.67%-24.41%). Collectively, PBM, FGC and ACC comprised 81.80% of all completed fixed prosthodontics units. There were observed trends of increased use of all types of all-ceramic containing restorations, all types of all-gold containing restorations, all types of partial coverage restorations and specifically ceramic onlays and gold onlays. There were observed trends of reduced use of cast gold post-cores and all types of bridges. PBM crowns were the mainstay laboratory-fabricated fixed prosthodontic unit completed over 10 years of undergraduate student fixed prosthodontics clinical practice.

Esthetic and functional rehabilitation of hypomineralized first permanent molars using prefabricated versus custom made zirconia crowns: a 12-month follow-up study

Background: Molar incisor hypomineralisation is defined as “hypomineralisation of systemic origin, presenting as demarcated, qualitative defects of the enamel of one to four first permanent molars frequently associated with affected incisors. MIH is also considered as a public health issue since it leads to pain, poor esthetics and has a negative impact on the quality of life. Thus, managing patients with MIH requires a variety of patient management approaches, materials, and techniques ranging from Intracoronal to extracoronal full or partial coverage restorations. To evaluate the efficacy of prefabricated zirconia crowns and custom-made zirconia crowns used on hypomineralised molars and to compare their efficacy in terms of gingival health, surface integrity, retention, parental satisfaction, time and cost over a time period of baseline (1day), 3, 6, 9 and 12 months.Methods: Twenty-six hypomineralized first permanent molars from children aged 7-12 years indicated for full coverage restorations were randomly selected from the Out Patient Department. The selected teeth (molars) were then randomly allocated into two groups (13 each) according to the type of crown used, namely Group A-prefabricated zirconia crowns (n=13) and group B-custom-made zirconia crowns (n=13). Tooth preparation was done according to the crown selected and all the crowns were cemented using resin-based cement. Patients were recalled and the follow-up was done by single trained examiner.Results: Clinical success for both the crowns were similar with no statistical difference between them.Conclusions: Both the crowns proved to be clinically successful.

Clinical performance of resin-matrix ceramic partial coverage restorations: a systematic review.

ObjectiveTo evaluate clinical performance of the new CAD/CAM resin-matrix ceramics and compare it with ceramic partial coverage restorations.Materials and methodsAn electronic search of 3 databases (The National Library of Medicine (MEDLINE/PubMed), Scopus, and the Cochrane Central Register of Controlled Trials) was conducted. English clinical studies published between 2005 and September 2020 that evaluated the clinical performance of CAD/CAM resin-matrix ceramics inlays, onlays, or overlays were selected. The primary clinical question was applied according to PICOS strategy (Population, Intervention, Comparison, Outcome, Study design). The included studies were individually evaluated for risk of bias according to the modified Cochrane Collaboration tool criteria.ResultsA total of 7 studies were included according to the established inclusion and exclusion criteria. From the included studies, 6 were randomized clinical trials while one study was longitudinal observational study without control group. According to the results of the included studies, the success rate of CAD/CAM resin-based composite ranged from 85.7 to 100% whereas the success rate reported for ceramic partial coverage restorations ranged from 93.3 to 100%. Fractures and debondings are found to be the most common cause of restorations failure.ConclusionCAD/CAM resin-based composite can be considered a reliable material for partial coverage restorations with clinical performance similar to glass ceramic restorations. However, this result needs to be confirmed in long-term evaluations.Clinical relevanceCAD/CAM resin-based composites provide a potential alternative to ceramic indirect restorations. However, clinicians must be aware of the lake of knowledge regarding long-term outcome.

Comparative evaluation of clinical performance of ceramic and resin inlays, onlays, and overlays: A systematic review and meta analysis.

Background:Advances in adhesive technologies and escalation in esthetic demands have increased indications for tooth-colored, partial coverage restorations. Recently, material knowledge has evolved, new materials have been developed, and no systematic review has answered the question posed by practitioners: Is the clinical efficacy of resin or ceramic better, for inlay, onlay, and overlay in the long run?Aim:The aim of this systematic review and meta-analysis was to evaluate the clinical performance of ceramic and resin inlays, onlays, and overlays and to identify the complication types associated with the main clinical outcomes.Materials and Methods:Two reviewers (VN and AJ) searched PubMed, Embase, and Cochrane Central registry of controlled trials for published articles between 1983 and 2020 conforming to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines for systematic reviews. Only clinical studies which met the following criteria were included (1) studies regarding ceramic and resin inlays, onlays, and overlays were included; (2) randomized controlled trials, retrospective or prospective studies conducted in humans; (3) studies with a dropout rate <50% 4) studies with a follow-up higher than 5 years.Results:Of 1718 articles, 21 articles were selected. At 5 years, the estimated survival rates for resin (n = 129) was 86%, feldspathic porcelain (n = 1048) was 90%, and glass ceramic (n = 2218) was 92%; at 10 years, the survival of resin was 75% (n = 115), feldspathic porcelain was 91% (n = 1829), and glass ceramic was 89% (n = 1075).Conclusion:The meta-regression indicated that ceramic partial coverage restorations (feldspathic porcelain and glass-ceramic) outperformed resin partial coverage restorations both at 5-year and 10-year follow-up. When compared between ceramic types, glass ceramics outperformed feldspathic porcelain at 5 years' follow-up and feldspathic porcelain outperformed glass ceramics at 10 years' follow-up. The failures were mostly due to fractures (6.2%), endodontic problems (3%), secondary caries (1.7%), and debonding which was 0.9%.

Realization of Bonded Restorations with Partial Anchorage: A Survey among Dentists in Private Practice in Casablanca Morocco

Objectives: The aim of this study was to assess the prevalence of realization of resin-bonded partial-coverage restorations and to determine the frequencies of reasons to indicate theses restorations in dental office. Methods: In this cross-sectional study, a 22-question questionnaire was sent to 309 practitioners randomly selected from a list provided by the South Regional Council of Dental Registry. Average significance and Chi-square tests were used to identify the frequency, pattern, and significance of the response variables identified. Results: The response rate of our study was 79,6%. Our survey revealed that 52,4% of practitioners use resinbonded prosthesis in their daily practice. For the 47,6% who avoided it, the principal reasons were lack of training and the high price of bonding products. 81,1% of dentists have reported the need of continuing training in adhesive prosthesis and the type of training the most chosen was practical workshops for 55,5% of practitioners. Also, veneers (73,6%), resin bonded fixed partial dentures (58,9%) and inlays (58,1%) were the more used types of resinbonded partial-coverage prosthesis according to our study. Discussion: Similarly to several studies on adhesive prosthesis, our study showed that resin-bonded partialcoverage restorations are not frequently used comparing to cemented restorations. This is due to the lack of training and practice. For that, the major part of practitioners of our study and of similar ones, reported the need of continuing training to stay updated with the new technics in dentistry and to provide quality services to patients. Conclusion: The evolution of adhesive materials and the emergence of new techniques powered a change in the restorative adhesive dentistry. This requires practitioners to update knowledge and skills regularly to match the changing complexity of healthcare needs

Marginal Adaptation of CAD/CAM Restorations: A Systematic Review

Background: Several treatment options are available for restorative dental treatment of moderate to large teeth defects. However, in recent years, improved computer-aided design and computer-aided manufacturing (CAD/CAM) technology show several advantages, including favorable esthetic results, conservative preparation techniques and cost-effectiveness hence the aim of the study was to search for the best available evidence in investigating whether CAD/CAM fabricated partial coverage restorations will show better marginal adaptation and provide an evidence-based clinically relevant statement.&#x0D; Methodology: An extensive search was performed using four online databases. Search strategies were developed for each online database, the studies were reviewed by three independent authors, and inclusion/exclusion criteria were applied and the quality of the included studies was assessed. Results: The initial search resulted in 998 studies from all the databases. Six clinical studies were identified as relevant to the research question and were included in the qualitative assessment.&#x0D; Conclusions: Marginal adaptation of CAD/CAM-fabricated restoration shows excellent clinical outcomes in short-term observation periods. There is a need for clinical trials that compare the clinical outcomes of CAD/CAM-fabricated restoration to direct composite restorations.

Fatigue failure and success rate of lithium disilicate table-tops as a function of cement thickness.

Purpose Under thin, partial coverage restoration the proper cement thickness to be clinically employed still remains an issue. The aim of this study was to determine the failure and success rates of simplified lithium disilicate occlusal veneers as a function of cement thickness. The null hypothesis was that cement thickness has no effect on the fatigue resistance.Methods Sound human molars were severed in a plane parallel to the occlusal surface to create a flat dentin surface surrounded by enamel edges. Forty-five occlusal veneers 1.0 mm thick (IPS e.max CAD LT) were luted to the teeth with Multilink Automix resin cement, creating 3 experimental groups (n=15) with cement thicknesses of 50, 100, and 200 µm. The restorations were fatigue-cycled using a ball mill machine containing zirconia and stainless steel spheres. Twelve 60 min cycles were performed. Survival statistics were applied to "failure" and "success" events, comparing the three groups using a log-rank Mantel-Cox test and a log-rank test for trends (alpha = 0.05).Results The failure and success rates were not significantly influenced by cement thickness (P = 0.137 and P = 0.872, respectively); thus, the null hypothesis was accepted. However, when log-rank test for trends was applied to failure events, the tendency to have less failures with increasing thicknesses was found statistically significant (P = 0.047).Conclusions The cement thickness within the range adopted here did not have a significant effect on the failure or success rate of lithium disilicate occlusal veneers when exposed to randomized impact stresses generating fatigue phenomena.

Clinical performance of esthetic ceramic partial-coverage restorations with supra-gingival margin using minimally invasive tooth preparation method according to the concept of adhesive dentistry

Clinical performance of esthetic ceramic partial-coverage restorations with supra-gingival margin using minimally invasive tooth preparation method according to the concept of adhesive dentistry

Tooth-cusp preservation with lithium disilicate onlay restorations: A fatigue resistance study.

This study examined the in vitro fatigue resistance of maxillary premolars with 2 mm or 3 mm preserved cusp thicknesses restored with lithium disilicate onlays. Premolars(N=48) were divided into six groups. Onlays for groups 1 to 4 preserved a 3 mm functional (G1), 2 mm functional (G2), 3 mm nonfunctional (G3), or 2 mm nonfunctional (G4) buccal-lingual cusp width. Onlays for group 5 (G5, control) replaced both cusps. Group 6 (G6) samples were identical to G1 with added retentive boxes. Lithium disilicate onlays were exposed to thermocycling (10000 cycles, 5°C-55°C, 30s/cycle) and mechanical loading (1.2 million cycles at 1.4Hz and 70 N). All samples were examined for onlay debonding or cusp or onlay fracture. Failure rates were 75%(G1), 0.0%(G2), 12.5%(G3), 0.0%(G4), 0.0%(G5), and 0.0%(G6). The difference in percent failure between the groups preserving the functional cusps (37.5%) and the groups preserving the nonfunctional cusps (6.3%) was statistically significant (P=.04; 95%CI:2.11-55.66). No cusp or restoration fractures were observed; all failures were due to debonding of the restoration. Teeth with thin remaining cusps that were restored with bonded lithium disilicate onlay restorations were not prone to fracture. Retentive preparation features that physically eliminated lateral displacement prevented onlay debonding even though the ceramic-enamel margin was directly at the occlusal contact. The use of adhesively retained lithium disilicate ceramic onlays may be a viable alternative to full coverage restorations and may challenge traditionally accepted principals related to preparation resistance and retention form of ceramic partial coverage restorations.

10.9-year survival of pressed acid etched monolithic e.max lithium disilicate glass-ceramic partial coverage restorations: Performance and outcomes as a function of tooth position, age, sex, and the type of partial coverage restoration (inlay or onlay)

Statement of problemLong-term clinical data on the survival of pressed lithium disilicate glass-ceramic when used with partial coverage restorations and the effect that different technical and clinical variables have on survival are sparse. PurposeThe purpose of this clinical study was to determine the 10.9-year survival of pressed lithium disilicate glass-ceramic partial coverage restorations and associated clinical parameters on outcomes. Material and MethodsIndividuals requiring single unit defect-specific partial coverage restorations in any area of the mouth were recruited in a clinical private practice. Participants were offered the options of partial coverage cast gold or glass-ceramic (lithium disilicate) restorations. Only participants that chose glass-ceramic partial coverage restorations were included in the study. The overall survival of the glass-ceramic restorations was assessed by the clinical factors (participant’s age, sex, dental arch, tooth position in dental arch, type of partial coverage restoration, and ceramic thickness) determined at recall. The effect of this clinical parameters was evaluated by using Kaplan-Meier survival curves accounting for attrition bias and other reasons for failure. The statistical significance of differences between parameters was determined by using the log rank test (α=.05). ResultsA total of 304 participants requiring 556 lithium disilicate restorations were evaluated. The mean age for the participant at the time of restoration placement was 62 with a range of 20 to 99 years, 120 were men and 184 were women. A total of 6 failures (bulk fracture or large chip) requiring replacement were recorded with the average time to failure of 2.4 (0.8-9.2) years. The total time at risk computed for these units was 1978.9 years providing an estimated failure risk of 0.3% per year. The 10-year estimated cumulative survival was 95.6%.The estimated cumulative survival of inlays (n=246) and onlays (n=305) were 93.9% and 98.3%, at 9.9 and 9.8 years, respectively (P<.05). Of the 6, there were 3 failures recorded for the partial coverage inlay restorations. The total time at risk for these inlays was 786.79 years providing an estimated risk of 0.38% per year. The other 3 failures recorded occurred for the partial coverage onlay restorations. The total time at risk for the onlays was 1032.17 years providing an estimated risk of 0.29% per year. The failures occurred in the molar region only. There were no failures recorded for the anterior partial coverage inlays (n=5). The total time at risk computed for the anterior units was 21.55 years providing an estimated risk of 0% per year.There was no statistically significant difference in the survival of partial coverage restorations among men and women, different age groups, or position in the dental arch. The thickness of the restoration had no influence on the survival of glass-ceramic partial coverage restorations. ConclusionsPressed lithium disilicate defect-specific partial coverage restorations reported high survival rate over the 10.9-year period with an overall failure rate of 0.3% per year and limited to the molar teeth. Risk of failure at any age was minimal for both men and women.