Fired ceramic inlays: a 6-year follow up

Long-term Clinical Performance of Composite Resin or Ceramic Inlays, Onlays, and Overlays: A Systematic Review and Meta-analysis

CLINICAL RELEVANCE

Composite resin or ceramic inlays, onlays, and overlays can achieve high long-term survival and success rates.

SUMMARY

Survival of Cast Gold and Ceramic Onlays Placed in a School of Dentistry: A Retrospective Study

PURPOSE

This study was done to compare the survival rates of cast gold and ceramic onlays placed in a dental school setting.

MATERIAL AND METHODS

An electronic search was conducted in the patient records at Adams School of Dentistry, University of North Carolina at Chapel Hill for onlay codes that were in the database (From 1998 until 2018). Progress notes and radiographs were scrutinized to establish the survival time of the restorations. Any complications that occurred during the life time of the restorations were noted. The survival was summarized by categorization based on ranges of survival time in years; group 1: 1 to 5 years, group 2: 6 to 22 years. The mean survival time and standard deviation were calculated. One-way ANOVA was used to determine whether there was a statistically significant difference in the survival times between gold and ceramic onlays.

RESULTS

The mean survival rate of cast gold onlays (86.6%) was comparable to that of ceramic onlays (81.1%). The gold onlays in Group 1 had a higher mean survival time (2.43 years) than the ceramic onlays (2.03 years). This difference was statistically significant (p = 0.002). The ceramic onlays in Group 2 had a mean survival time of 19.75 years while gold onlays had a mean survival time of 17.63 years. This difference was not statistically significant (p = 0.91).

CONCLUSION

It was concluded that while the survival rate of ceramic onlays (81.1%) was inferior to that of cast gold onlays (86.6%), it was comparable.

Restoration Survival: Revisiting Patients' Risk Factors Through a Systematic Literature Review

A literature review was conducted to investigate the influence of patient-related factors on restoration survival in posterior permanent teeth as well as to report the methods used to collect these factors. The selection of articles on longitudinal clinical studies investigating the survival of posterior restorations (except full crowns and temporary fillings) and including patient-related factors was performed by applying predefined criteria. The review was organized into two parts, the first describing how patient factors were assessed in the studies (n=45) and the second presenting the statistical significance (n=27) and size of the effect (n=11) of these factors on restoration survival. Patient-related factors mentioned in the studies included age; gender; caries risk; caries activity/severity; decayed, missing, filled teeth; number of restorations; oral hygiene; and bruxism, among others. Sixteen studies included the patient age or age range in the analysis, which was found to be significant in 47% of the studies. Regarding gender, four of 17 reports found a significant effect on survival, showing more failures for men in three studies. The caries risk profile or related variables were included in the analysis of 15 studies, and a significant effect on survival was reported for high-caries-risk individuals (or related variables) in 67% of these studies. Bruxism was also found to influence restoration survival in three of six studies where this variable was investigated. Some issues were found regarding the reporting of methods used to classify patients according to risk and were thoroughly discussed. In view of the information gathered in this review, the assessment of patient factors along with other variables should become part of clinical studies investigating restoration survival, since several of these factors were shown to influence the failure of restorations, regardless of the material type.

Clinical evaluation of ceramic inlays and onlays fabricated with two systems: 12-year follow-up

OBJECTIVES

The aim of this study was to evaluate the 12-year clinical performance of sintered (Duceram, Dentsply-Degussa, Dentsply International Inc., PA, USA)-D and pressable (IPS Empress, Ivoclar-Vivadent, Schaan, Leichtenstein)-IPS ceramic inlay and onlay restorations.

METHODS

Eighty-six restorations were placed in 35 patients with a median age of 33 years by a single operator. The restorations were luted with dual-cured resin luting material (Variolink II, Ivoclar-Vivadent, Schaan, Leichtenstein) and Syntac Classic adhesive under rubber dam. The evaluations were conducted by two independent investigators at the baseline, 1, 2, 3, 5, and 12 years using the modified USPHS criteria.

RESULTS

At the 12-year recall, 22 patients were evaluated (62.86 %), totalling 48 (55.81 %) restorations. Seven restorations were fractured (one from Duceram and six from IPS), eight restorations presented secondary caries (three from Duceram and five from IPS), nine restorations showed unacceptable defects at the restoration margin and needed repair or replacement (two from Duceram and seven from IPS), and four IPS restorations presented pulp sensitivity.

CONCLUSION

Chi-square and Mann-Whitney tests revealed that IPS Empress system showed the best results for color match and surface texture (p < 0.05) but a significant worse result for fracture (p = 0.05). Wilcoxon test showed significant differences in relation to color match, surface texture, marginal discoloration, and marginal integrity between the baseline and 12-year recall for both ceramic systems.

CLINICAL SIGNIFICANCE

This long-term clinical study observed that the main reasons for failure of ceramic restorations were related to fracture, recurrent caries, and decreased marginal integrity over time. Carefully monitoring of the ceramic-tooth interface may extend their clinical longevity.

Cementation of Glass-Ceramic Posterior Restorations: A Systematic Review

Aim. The aim of this comprehensive review is to systematically organize the current knowledge regarding the cementation of glass-ceramic materials and restorations, with an additional focus on the benefits of Immediate Dentin Sealing (IDS). Materials and Methods. An extensive literature search concerning the cementation of single-unit glass-ceramic posterior restorations was conducted in the databases of MEDLINE (Pubmed), CENTRAL (Cochrane Central Register of Controlled Trials), and EMBASE. To be considered for inclusion, in vitro and in vivo studies should compare different cementation regimes involving a “glass-ceramic/cement/human tooth” complex. Results and Conclusions. 88 studies were included in total. The in vitro data were organized according to the following topics: (micro)shear and (micro)tensile bond strength, fracture strength, and marginal gap and integrity. For in vivo studies survival and quality of survival were considered. In vitro studies showed that adhesive systems (3-step, etch-and-rinse) result in the best (micro)shear bond strength values compared to self-adhesive and self-etch systems when luting glass-ceramic substrates to human dentin. The highest fracture strength is obtained with adhesive cements in particular. No marked clinical preference for one specific procedure could be demonstrated on the basis of the reviewed literature. The possible merits of IDS are most convincingly illustrated by the favorable microtensile bond strengths. No clinical studies regarding IDS were found.

Atmospheric moisture effects on the testing rate and cementation seating load following resin-strengthening of a soda lime glass analogue for dental porcelain

OBJECTIVES

To investigate if resin-cementation of a soda lime glass dental analogue could elucidate information regarding the pattern of resin-reinforcement when coated in an environment actively scavenged of moisture.

METHODS

192 soda lime disc-shaped specimens (alumina particle air abraded, hydrofluoric acid-etched and silane coated) were randomly assigned to eight groups (n=24 per group) prior to resin-coating at seating loads of 5 N (Groups A-D) and 30 N (Groups E-H) in an environment where moisture was actively scavenged and maintained below 15 ppm. Following one week storage the discs were tested in biaxial flexure at crosshead rates of 0.01, 0.1, 1 and 10mm/min. Analysis of group means was performed utilising a general linear model univariate analysis and post hoc all paired Tukey tests (P<0.05).

RESULTS

The general linear model univariate analysis identified the mean biaxial flexure strength (BFS) was significantly influenced by the factors resin-cementation seating load (P<0.001) and crosshead speed of the applied load (P<0.001) with a significant interaction (P=0.008) between both factors. The linear logarithmic regression curves fitted to the group mean BFS data plotted against the crosshead speed highlighted significant differences between the pattern of resin-strengthening for the cementation loads and testing conditions.

CONCLUSIONS

The decrease in resin-penetration expected within the 'resin-ceramic hybrid layer' following removal of the 30 N seating load was proposed as the modifying resin-strengthening parameter. These observations are supported by the viscoelastic and creep behaviour of resins at slow testing rates which becomes the dominant or determining phenomenon.

Influence of resin cement polymerization shrinkage on stresses in porcelain crowns

OBJECTIVE

The aim of this study was to analyze the influence of polymerization shrinkage of the cement layer on stresses within feldspathic ceramic crowns, using experimentally validated FEA models for (1) increasing occlusal cement thickness; and, (2) bonded versus non-bonded ceramic-cement interfaces.

METHODS

2-D axial symmetric models simulated stylized feldspathic crowns (1.5mm occlusal thickness) cemented with resin-cement layers of 50-500μm on dentin preparations, being loaded (500N) or not. Ceramic-cement interface was either bonded or not. Cement was bonded to the dentin in all models. Maximum axial shrinkage of 0%, 1%, 2%, 3%, 4% and 4.65% were simulated. The first principal stresses developing in the cementation surface at the center and at the occluso-axial line-angle of the crown were registered.

RESULTS

Polymerization shrinkage of the cement increased tensile stresses in the ceramic, especially in loaded non-bonded crowns for thicker cement layers. Stresses in loaded non-bonded crowns increased as much as 87% when cement shrinkage increased from 0% to 4.65% (100-187MPa), for a 500μm-thick cement. Increasing polymerization shrinkage strain raised the tensile stresses, especially at the internal occlusal-axial line-angle, for bonded crowns.

SIGNIFICANCE

Changes in the polymerization shrinkage strain (from 0% to 4.65%) have little effect on the tensile stresses generated at the cementation surface of the ceramic crowns, when the occlusal cement thickness is thin (approx. 50μm for bonded crowns). However, as the cement becomes thicker stresses within the ceramic become significant.

Clinical Evaluation of Ceramic Inlays and Onlays Fabricated With Two Systems: Five-Year Follow-Up

This study evaluated the five-year clinical performance of ceramic inlays and onlays made with two systems: sintered Duceram (Dentsply-Degussa) and pressable IPS Empress (Ivoclar Vivadent). Eighty-six restorations were placed by a single operator in 35 patients with a median age of 33 years. The restorations were cemented with dual-cured resin cement (Variolink II, Ivoclar Vivadent) and Syntac Classic adhesive under rubber dam. The evaluations were conducted by two independent investigators at baseline, and at one, two, three, and five years using the modified United States Public Health Service (USPHS) criteria. At the five-year recall, 26 patients were evaluated (74.28%), totalling 62 (72.09%) restorations. Four IPS restorations were fractured, two restorations presented secondary caries (one from IPS and one from Duceram), and two restorations showed unacceptable defects at the restoration margin and needed replacement (one restoration from each ceramic system). A general success rate of 87% was recorded. The Fisher exact test revealed no significant difference between Duceram and IPS Empress ceramic systems for all aspects evaluated at different recall appointments (p&gt;0.05). The McNemar chi-square test showed significant differences in relation to marginal discoloration, marginal integrity, and surface texture between the baseline and five-year recall for both systems (p&lt;0.001), with an increased percentage of Bravo scores. However, few Charlie or Delta scores were attributed to these restorations. In conclusion, these two types of ceramic materials demonstrated acceptable clinical performance after five years.

Seven-year clinical performance of CEREC-2 all-ceramic CAD/CAM restorations placed within deeply destroyed teeth

OBJECTIVES

Adhesively luted all-ceramic restorations represent a promising way to preserve and stabilize weakened tooth substance, but little information is published about the clinical performance of extensive all-ceramic restorations.

MATERIALS AND METHODS

A total of 78 large CEREC 2™ single-tooth all-ceramic restorations had been placed in 35 patients. After 7 years, 59 teeth in 25 patients were reevaluated according to USPHS or modified USPHS criteria regarding aesthetic properties, e.g., "anatomic form," "color match," and "marginal discoloration"; functional properties, e.g., "marginal integrity," wear expressed by the criteria "proximal contact" and "static/dynamic occlusal relationship"; and biological properties, e.g., "tooth vitality" and "secondary caries". Additionally, the "proportion of margin below/above cemento-enamel junction" was included.

RESULTS

Two restorations had failed prior to the 7-year recall, one due to a bulk fracture of the restoration and one due to poor marginal integrity (rated "Charlie") after 4 years. Other six restorations were rated as failure at the 7-year evaluation (three restorations revealed secondary caries, one was bulk fracture of the Cerec 2 restoration, and two failures were related to endodontic problems resulting in extraction or amputation of one root, respectively), resulting in a failure rate of 13.1% after 7 years. A total of 96.4% of the restorations revealed sufficient ratings for esthetic properties "anatomic form," "color match," "marginal discoloration," and "marginal integrity".

CONCLUSIONS

The survival rate of 86.9% at the 7-year recall demonstrates that adhesively luted all-ceramic CAD/CAM-generated restorations are suitable for restoration of extended coronal defects.

CLINICAL RELEVANCE

CAD/CAM-generated all-ceramic restorations facilitate the reconstruction of deeply destroyed teeth irrespectively of the location of the cavity margins.

Ceramic materials in dentistry: historical evolution and current practice

Dental ceramics are presented within a simplifying framework allowing for facile understanding of their development, composition and indications. Engineering assessments of clinical function are dealt with and literature is reviewed on the clinical behaviour of all-ceramic systems. Practical aspects are presented regarding the choice and use of dental ceramics to maximize aesthetics and durability, emphasizing what we know and how we know it.

Statistical failure analysis of adhesive resin cement bonded dental ceramics

The goal of this work is to quantitatively examine the effect of adhesive resin cement on the probability of crack initiation from the internal surface of ceramic dental restorations. The possible crack bridging mechanism and residual stress effect of the resin cement on the ceramic surface are examined. Based on the fracture-mechanics-based failure probability model, we predict the failure probability of glass-ceramic disks bonded to simulated dentin subjected to indentation loads. The theoretical predictions match experimental data suggesting that both resin bridging and shrinkage plays an important role and need to be considered for accurate prognostics to occur.

To what extent does the longevity of fixed dental prostheses depend on the function of the cement? Working Group 4 materials: cementation

AIMS/BACKGROUND

The objective of this review was to define the impact of cementation mode on the longevity of different types of single tooth restorations and fixed dental prostheses (FDP).

METHODS

Literature search by PubMed as the major database was used utilizing the terms namely, adhesive techniques, all-ceramic crowns, cast-metal, cement, cementation, ceramic inlays, gold inlays, metal-ceramic, non-bonded fixed-partial-dentures, porcelain veneers, resin-bonded fixed-partial-dentures, porcelain-fused-to-metal, and implant-supported-restorations together with manual search of non-indexed literature. Cementation of root canal posts and cores were excluded. Due to lack of randomized prospective clinical studies in some fields of cementation, recommendations had to be based on lower evidence level (Centre of Evidence Based Medicine, Oxford) for special applications of current cements.

RESULTS

One-hundred-and-twenty-five articles were selected for the review. The primary function of the cementation is to establish reliable retention, a durable seal of the space between the tooth and the restoration, and to provide adequate optical properties. The various types of cements used in dentistry could be mainly divided into two groups: Water-based cements and polymerizing cements. Water-based cements exhibited satisfying long-term clinical performance associated with cast metal (inlays, onlays, partial crowns) as well as single unit metal-ceramic FDPs and multiple unit FDPs with macroretentive preparation designs and adequate marginal fit. Early short-term clinical results with high-strength all-ceramic restorations luted with water-based cements are also promising. Current polymerizing cements cover almost all fields of water-based cements and in addition to that they are mainly indicated for non-retentive restorations. They are able to seal the tooth completely creating hybrid layer formation. Furthermore, adhesive capabilities of polymerizing cements allowed for bonded restorations, promoting at the same time the preservation of dental tissues.

Developing meaningful systematic review of CAD/CAM reconstructions and fiber-reinforced composites

OBJECTIVE

Clinical literature was examined for evidence supporting use of CAD/CAM reconstructions and fiber-reinforced materials.

MATERIALS AND METHODS

Potential evidence was identified via databases [PubMed; EMBASE (R) Drugs & Pharmacology; Center for Reviews and Dissemination, University of York; Cochrane Library], hand search of non-indexed literature, secondary reference searches, and personal contacts with clinical trial PI's. Search terms included: dental restorations; CAD/CAM; CEREC; LAVA; CERCON; Procera; inlay/onlay; dental prosthesis; fiber-reinforced composite (FRC).

RESULTS

Two randomized-controlled clinical trials were identified as examined in one Cochrane Collaboration review relevant to CAD/CAM inlays. One systematic review of 15 CAD/CAM inlay studies was examined. Six studies were identified of three commercial FRC endodontic posts and eight reported on FRC use for fixed denture prostheses. Fifteen ongoing prospective trials were identified studying CAD/CAM fabricated zirconia-based prostheses. A total of 76 papers were referenced including those related to use of in vitro measures as evidence.

CONCLUSIONS

Review of the Cochrane analysis raised concerns that typical RCT protocols may prove insufficient for stratification of confounding variables (patient, practitioner, material) when treatment outcomes are primarily prosthesis- or material-based (not patient-based, e.g., as in fracture). RCT designs are most straightforward when treatment outcomes are patient-based (e.g., soft tissue changes). When treatment responses are material-based, controls also become difficult to define and studies become tests of equivalency/superiority; where well-stratified cohort designs are likely preferred. Large numbers of independent cohort studies support the use of CAD/CAM ceramic inlay/onlay restorations and crowns but many complications inhibit the application of high-level systematic review. Except perhaps for fiber-based endodontic posts, the clinical FRC literature appears insufficient for expert review. Single in vitro measures cannot currently serve as evidence for clinical practice, except in limited cases of simple function (e.g., impression material accuracy). Batteries of in vitro measures are often applied during materials development but cannot substitute for clinical study.

Four year performance of dentine-bonded all-ceramic crowns

AIM

This paper reports a prospective evaluation of 59 dentine-bonded crowns placed in a dental school environment for patients, a majority of whom were suffering from tooth substance loss.

RESULTS

Forty-eight crowns (83%) were available for examination, with their mean age since placement being 3.9 years. The mean age of the patients in whom the crowns were placed was 37.5 years. Three crowns had failed due to porcelain fractures, an overall failure rate of 6%. Two of the failures were minimal cracks of which the patient was unaware, and one, in an upper premolar tooth, because of crown fracture. No secondary caries was noted, incidence of pulp symptoms or pulp death was nil, and margins were rated as 'excellent' in 42 crowns (86%).

CONCLUSION

The dentine bonded crowns assessed in this study showed excellent retention and low incidence of fracture at four years. This technique would appear to be suitable for a variety of clinical indications, including treatment of tooth substance loss, although the results presented in this study are relatively short term in relation to the anticipated life of restorations.

In vivo and in vitro evaluation of marginal fit of class II ceromer inlays

The aim of this study was to evaluate the marginal adaptation of class II ceromer (Targis, Vivadent) indirect inlay restorations under both in vivo and in vitro conditions. Twenty Targis inlays were produced for class II inlay cavities (13 mandibular and seven maxillary teeth) in 20 patients. The in vivo adaptation of the inlay to the tooth cavity was evaluated by means of silicone replica technique. For in vitro evaluation, 20 mesio-occluso-distal (MOD) Targis inlays were made in extracted upper molars. Half of the inlays were cemented with Variolink high-viscosity resin cement while the other half was cemented with Variolink Ultra. The replica specimens and in vitro samples were sectioned buccolingually and mesiodistally, and marginal adaptation was evaluated at both proximal and occlusal margins at 200x magnification under a light microscope. The data was analyzed with anova (P < 0.05). The in vivo mean film thickness values for occlusal and proximal locations were recorded as 73 and 132 microm respectively. In vitro mean marginal fit values were observed as 48 and 67 microm for occlusal and proximal margins of inlays luted with Variolink II high viscosity. The marginal fit values recorded under in vivo conditions were higher in magnitude than the measurements obtained under in vitro conditions. The use of a highly filled resin luting agent with an ultrasonic insertion technique did not cause an increase in marginal gap width of the inlay.

Fracture Resistance of Premolars Restored with Partial Ceramic Restorations and Submitted to Two Different Loading Stresses

The fracture resistance of ceramic restorations is associated with the quantity of the dental structure removed. In relation to the fracture resistance, preference should be given to inlay restorations rather than to onlays; however, no restorative technique was able to attain the fracture resistance of intact teeth.

Clinical performance and marginal adaptation of class II direct and semidirect composite restorations over 3.5 years in vivo

OBJECTIVE

The study evaluated the clinical performance and marginal adaptation of direct and semi-direct class II composite restorations in a split-mouth design over 3.5 years.

DESIGN

44 upper posterior teeth in 11 adults with primary carious lesions were treated with 22 direct and 22 semi-direct restorations. Conventional cavities were prepared for both types of restorations. A fine fine hybrid composite (APH) and a multifunctional adhesive system (Prisma universal bond 3) were used for all restorations. The incremental "3-sited light curing" technique was applied to direct restorations. Semi-direct inlays were prefabricated on silicone casts and post-cured using light and heat. Clinical performance was evaluated using modified USPHS parameters, while marginal adaptation was judged on replicas, using SEM and a standardized evaluation technique.

RESULTS

Clinical results after 3.5 years revealed a 100% retention rate with no fractures, sensitivity or recurrent caries for both types of restorations. SEM-evaluation of the occlusal margins showed at the tooth-restoration interface relatively low rates of marginal openings over the observation period (4-8%). Marginal restoration fractures ranged between 1 and 2%, marginal tooth fractures between 3 and 9%. Differences between the restorative techniques and after the different time observation periods were not statistically significant. Proportions of marginal fractures and openings at the restoration-luting composite interface were less than 10% after 3.5 years.

CONCLUSION

The results indicated no significant differences for direct and semi-direct fine hybrid composite restorations in medium size cavities in posterior teeth with respect to clinical performance and marginal adaptation over 3.5 years.

Longevity of ceramic inlays and onlays luted with a solely light-curing composite resin

OBJECTIVES

To determine the longevity of heat-pressed glass ceramic inlays and onlays luted with solely light-curing composite resin.

METHODS

The records of patients who had received a ceramic inlay or onlay at the Heidelberg University Department of Conservative Dentistry from 1993 to 2002 were evaluated. The mean observation time and the survival probability of the ceramic inlays and onlays was calculated with the aid of the Kaplan-Meier algorithm. This was done for the total number of all restorations as well as for various subgroups (number of surfaces, tooth type, endodontic condition at the time that the ceramic restoration was incorporated, experience of operator). The log-rank test was used to compare groups and look for significant differences, and p<0.05 was set to be statistically significant. In addition, 95% confidence intervals of the survival probability values were computed.

RESULTS

At the time of the last observation, 783 (96.7%) of these restorations were still in place. The mean observation period for all ceramic restorations was 17.3 months (SD 20.2), with an observation interval of between 0 and 116 months. The last loss of a ceramic restoration was observed 45 months after it had been placed, so that the survival probability of all ceramic restorations amounted to p=0.90 (95% confidence interval 0.86-0.94) from this time onward. Factors such as endodontic condition of tooth, type of tooth, position of tooth, extent of restoration, experience of operator or gender of patient had no significant influence on the survival probability of the ceramic restorations.

CONCLUSIONS

Heat-pressed glass ceramic inlays and onlays can be used successfully in routine clinical therapy. In addition, this type of inlays and onlays can be placed successfully with solely light-curing composite resin.

Clinical performance of large, all-ceramic CAD/CAM-generated restorations after three years

BACKGROUND

Adhesively luted all-ceramic restorations preserve and stabilize weakened tooth structure, but there is little published information about the clinical performance of large, all-ceramic restorations.

METHODS

In this pilot study, the authors placed 58 large, single-tooth, all-ceramic restorations in 26 patients using a computer-aided design/computer-aided manufacturing, or CAD/CAM, system (CEREC 2, Sirona Dental Systems GmbH, Bensheim, Germany). They documented the maximum height of the restoration and remaining cementoenamel junction, or CEJ. In 21 cases, rubber dam isolation was not possible during adhesive luting. They re-evaluated the restorations after three years according to the U.S. Public Health Service criteria.

RESULTS

After three years, the authors rated 56 (97 percent) of the 58 restorations as Bravo or better in regard to marginal integrity, secondary caries (four could not be rated), discoloration and anatomical form. One restoration was rated as Charlie because of poor marginal integrity, and one restoration had to be replaced owing to a bulk fracture. The authors rated the adequacy of proximal contact and occlusal relationships as acceptable-to-good for all restorations. Neither the extent of the remaining enamel at the cavity margin nor application of a rubber dam had any statistically significant influence (chi2 test, P > .05) on the clinical performance of the restorations after three years.

CONCLUSIONS

At the three-year recall appointment, the authors found that the adhesively luted all-ceramic restorations had successfully repaired large coronal defects, irrespective of the cavity margin location (that is, coronal or apical to the CEJ).

CLINICAL IMPLICATIONS

Tooth-colored, all-ceramic CAD/CAM-generated restorations are an alternative to conventional restorations if large coronal defects need to be treated.

Resin-modified glass ionomer cement and self-cured resin composite luted ceramic inlays. A 5-year clinical evaluation

OBJECTIVE

This study evaluated IPS Empress ceramic inlays luted with two chemical-cured luting agents, a resin-modified glass ionomer cement (Fuji Plus (F)) and a resin composite (RC) (Panavia 21 (P)).

METHODS

Seventy-nine ceramic inlays were placed in Class II cavities in 29 patients. At least two inlays were placed in each patient to compare the luting techniques intra-individually. In each patient half of the inlays were luted with F and the other half with P. The inlays were evaluated clinically, according to modified USPHS criteria (van Dijken, 1986), at baseline, after 6 months, and yearly during 5 years.

RESULTS

At 5 years, 71 inlays were evaluated. Two small partial fractures were observed at 3 years (1P, 1F). One inlay showed recurrent root caries at 4 years (P). Four inlays, two in each group showed non-acceptable color match (2P, 2F). Small defects were observed in 4 inlays (2P, 2F). A slight ditching of the cement margins was observed in both luting groups but did not seem to increase during the second half of the evaluation. No significant difference in durability was observed between the two luting agents.

SIGNIFICANCE

IPS Empress inlays luted with the chemical-cured RC and the resin-modified glass ionomer cement functioned satisfactory during the 5 years follow-up.

Ceramic Inlays and Onlays: Clinical Procedures for Predictable Results

The use of ceramics as restorative materials has increased substantially in the past two decades. This trend can be attributed to the greater interest of patients and dentists in this esthetic and long-lasting material, and to the ability to effectively bond metal-free ceramic restorations to tooth structure using acid-etch techniques and adhesive cements. The purpose of this article is to review the pertinent literature on ceramic systems, direct internal buildup materials, and adhesive cements. Current clinical procedures for the planning, preparation, impression, and bonding of ceramic inlays and onlays are also briefly reviewed. A representative clinical case is presented, illustrating the technique.

CLINICAL SIGNIFICANCE

When posterior teeth are weakened owing to the need for wide cavity preparations, the success of direct resin-based composites is compromised. In these clinical situations, ceramic inlays/onlays can be used to achieve esthetic, durable, and biologically compatible posterior restorations.

Intra-oral adhesive systems for ceramic repairs: a comparison

The aim of this investigation was to compare the bond strength of restorative composite resin to dental ceramic conditioned with primers and adhesives of various commercial repair kits. Three intra-oral ceramic repair systems--Silistor (Heraeus Kulzer), Cimara (Voco), Ceramic Repair (Vivadent)--were used on all-ceramic (IPS Empress 2, Ivoclar-Vivadent) substrate. Shear bond strength of restorative composite resin to substrate was tested after thermocycling and without thermocycling (n = 10). Substrate surfaces of the specimen after loading were examined microscopically (SEM). The highest bond strengths in both water-stored (7.0 +/- 5.7 MPa) and thermocycled conditions (2.5 +/- 1.8 MPa) were obtained with the Vivadent repair system, while the lowest values were observed with the Cimara system (0.6 +/- 1.4 MPa and 0.0 +/- 0.0 MPa, respectively). Shear bond strengths appeared to be significantly affected by thermocycling (ANOVA, P < 0.05). It is concluded that there are significant differences in the bond strengths of resin composites and ceramic substrate. The roughened surface does not necessarily provide a better bond strength; the bond strength of composite decreases with storage in water and after thermocycling. Bond strength values were generally low for all of the tested materials.

Clinical evaluation of class II Targis inlays: preliminary results after 1 year

The aim of this study was to evaluate the clinical performance of a new generation of restorative resin, Targis (Vivadent), in class II inlay restorations. Forty class II Targis inlays were placed (18 premolars, 22 molars) in 26 patients (mean age=25.5). All test teeth were vital. All restorations were in occlusion and were placed adhesively using Variolink II high viscosity (Vivadent) in combination with Syntac adhesive system under rubber-dam by the same operator. The restorations were evaluated at baseline and after 6 months and 1 year, according to modified United States Public Health Service (USPHS) criteria by two examiners. The parameters evaluated were: anatomical form, marginal adaptation, marginal discoloration, colour match, surface finish, gingival index and secondary caries. Post-operative sensitivity was determined by direct questioning. Regarding all of the clinical evaluation criteria all 40 inlays exhibited clinically acceptable scores after 1-year evaluation period. Relying on these early 1-year results, the new restorative material (Targis) seems to be promising in class II inlays.

In vitro wear simulation measurements of composite versus resin-modified glass ionomer luting cements for all-ceramic restorations

BACKGROUND

Although composite cements are generally indicated for cementation of all-ceramic restorations, some manufacturers of dental cements propose that resin-modified glass ionomers (RMGIs) may be used for cementation of high-strength ceramic restorations.

PURPOSE

This study was undertaken to compare the in vitro abrasion and attrition wear of two dual-cure cements (in dual-cure and self-cure modes) and two RMGI cements when placed between ceramic and enamel to simulate the margin of a restoration.

METHODS

Rectangular fragments of pressed ceramic (Empress 2) were cemented between the halves of bovine incisors sectioned mesiodistally, using one of the following materials: RelyX ARC, Variolink II, RelyX Luting, or ProTec CEM. The two resin cements were tested in dual-cure and self-cure modes. A three-body wear test was performed in the new Oregon Health Sciences University (OHSU) oral wear simulator (100,000 cycles; abrasion load: 20 N; attrition load: 90 N). Degree of conversion of resin cements was determined by Fourier transform infrared spectroscopy. Results were analyzed by analysis of variance and Tukey's test (p = .05). Epoxy replicas of wear specimens were observed in the scanning electron microscope.

RESULTS

No significant differences in abrasion wear (RelyX ARC dual-cure: 11 +/- 4.4 microm; RelyX ARC self-cure: 17 +/- 7.0 microm; Variolink dual-cure: 14 +/- 8.6 microm; Variolink self-cure: 23 +/- 10.7 microm) or attrition wear (RelyX ARC dual-cure: 18 +/- 6.4 microm; RelyX ARC self-cure: 31 +/- 4.5 microm; Variolink dual-cure: 32 +/- 6.8 microm; Variolink self-cure: 39 +/- 15.9 microm) were found between activation modes of the resin cements. ProTec CEM (32 +/- 8.7 microm) showed abrasion similar to that of Variolink II and RelyX ARC self-cure. Resin-modified glass ionomers showed more attrition wear than the resin cements (ProTec CEM: 62 +/- 13.0 microm; RelyX Luting: 69 +/- 7.1 microm). RelyX ARC showed a similar degree of conversion for both activation modes (dual-cure: 70 +/- 4.3%; self-cure: 68 +/- 1.2%), but Variolink II had a higher degree of conversion in dual-cure mode (67 +/- 0.5% vs 60 +/- 1.0%). Cement wear was accompanied by marginal breakdown and increased surface roughness of enamel and ceramic.

CONCLUSIONS

The activation mode of resin cements did not influence their wear resistance. The RMGIs underwent higher attrition wear than the resin cements.

CLINICAL SIGNIFICANCE

Increased submargination associated with marginal breakdown and increased roughness of the surrounding structures may be expected when ceramic inlays are cemented with resin-modified glass ionomers.

Systematic review of ceramic inlays

The purpose of the present study was to conduct a systematic review of ceramic inlays, assess the quality of published clinical studies, and determine the clinical effectiveness of ceramic inlays compared to other forms of posterior restorations. Prospective clinical trials of ceramic inlays published from 1990 to 2001 were retrieved by electronic and hand searching. The methodological quality of each study was assessed by two calibrated reviewers using a standardised checklist. The clinical effectiveness of ceramic inlays was evaluated in terms of failure rate, postoperative pain, and aesthetics. The results were compared to those of other forms of posterior restorations by means of an odds ratio. Among 46 articles selected for quality assessment, only five (10.6%) reported randomised controlled trials and 15 (32.6%) presented controlled clinical trials. The remaining 26 papers (56.5%) were longitudinal clinical trials lacking control groups. Only three papers fulfilled the requirement for statistical analysis to evaluate the clinical effectiveness of ceramic inlays. The results indicate no significant differences in longevity or postoperative sensitivity between ceramic and other posterior restorations over assessment periods of up to 1 year. It is concluded that no strong evidence is available to confirm the clinical effectiveness of ceramic inlays in comparison to other posterior restorations. Greater attention is required to the design and reporting of studies to improve the quality of clinical trials of ceramic inlays.

Resin-ceramic bonding: a review of the literature

Current ceramic materials offer preferred optical properties for highly esthetic restorations. The inherent brittleness of some ceramic materials, specific treatment modalities, and certain clinical situations require resin bonding of the completed ceramic restoration to the supporting tooth structures for long-term clinical success. This article presents a literature review on the resin bond to dental ceramics. A PubMed database search was conducted for in vitro studies pertaining to the resin bond to ceramic materials. The search was limited to peer-reviewed articles published in English between 1966 and 2001. Although the resin bond to silica-based ceramics is well researched and documented, few in vitro studies on the resin bond to high-strength ceramic materials were identified. Available data suggest that resin bonding to these materials is less predictable and requires substantially different bonding methods than to silica-based ceramics. Further in vitro studies, as well as controlled clinical trials, are needed.

Use of heat-pressed, leucite-reinforced ceramic on anterior and posterior onlays: a clinical report

The introduction of new techniques and materials in all-ceramic systems, together with improvements in resin bonding agents, has enabled the use of resin cements to directly bond ceramic crowns, veneers, and inlays/onlays to conservative tooth preparations. Directly bonded ceramic onlays can eliminate the need for conventional means of retention and allow the restoration of lost tooth structure with minimal tooth preparation. This article presents the use and short-term clinical performance of directly bonded, heat-pressed, leucite-reinforced ceramic onlays in both anterior and posterior areas of the mouth.

Restorations with extensive dentin/enamel-bonded ceramic coverage. A 5-year follow-up

The durability of restorations with extensive dentin/enamel-bonded posterior partial and complete ceramic coverages were investigated. The effect of luting with a dual-cured and a self-cured luting agent was also studied. In 110 patients, 182 ceramic coverages (IPS Empress) were placed. In 58 restorations, Syntac was used in combination with the dual-cured resin composite Variolink. In the other restorations luted with the chemically cured resin composite Bisfil 2B, 25 were bonded with Gluma, 57 with Allbond 2, and 42 with Syntac. Of the 182 ceramics, 13 (7.1%) were assessed as non-acceptable after a mean observation period of 4.9 yr (range 4.3 7.5 yr). The reasons for failure were fracture (5), lost restorations (4), secondary caries (3) and endodontic treatment (1). No significant differences in failure rate were seen between the two luting agents or between the three dentin-bonding agents. Ceramic coverages placed on non-vital teeth failed in 9.7% of cases (3/31) and on vital teeth in 6.6% (10/151). The success rate of the dentin-enamel-bonded ceramic coverages reduces the need for a traditional full-coverage therapy and/or post or pin(s) and core placement. The technique investigated showed many clinical advantages such as less destruction of healthy tissue, and avoidance of endodontic treatment and/or deep cervical placement of restoration margins.

Scientifically based rationale and protocol for use of modern indirect resin inlays and onlays

The desire to place esthetically pleasing, conservative, functionally stable, posterior restorative materials has steadily increased over the past 20 years. The creation of successful dentin bonding adhesives and appropriate resin luting cements has paved the way for the development of a myriad of indirect resin-based restorative materials. These materials have been specifically designed to overcome the negative attributes of their porcelain counterparts, and to simplify fabrication, insertion, and post-delivery adjustments. Possibly like no other product before, these restorative materials have met with instant clinical acceptance by many practitioners, and concern exists that these materials have not been sufficiently studied to warrant such widespread acceptance. This article presents an overview of the history and development of resin-based, esthetic, indirect systems, and offers the clinician a review of the literature supporting their role in posterior restorative dentistry. Additionally, a scientifically based protocol for preparation, impressing, provisionalization, and subsequent cementation and adjustment of indirect laboratory-processed resin inlays and onlays is presented.

Follow-up evaluation of a series of dentin-bonded ceramic restorations

PURPOSE

The results of a retrospective evaluation of 60 dentin-bonded full-coverage restorations with an average time in service of 2.4 years previously have been reported. The purpose of this study was to evaluate the crowns after a further 2 years in service.

MATERIALS AND METHODS

The 23 patients in the initial study whose restorations were found to be intact in June 1996 were contacted by mail and invited to present for review in October 1998. The restorations of 20 respondents were assessed by two examiners using modified United States Public Health Service criteria.

RESULTS

The patients had received a total of 53 restorations (mean age of restorations, 4.4 years; range, 5.5-3 yr). At the time of examination, 48 restorations were found to be intact. No secondary caries was detected in these restorations, and optimal scores for gingival health, anatomic form, and marginal discoloration were recorded for 39, 47, and 33 crowns, respectively. Color match was assessed as being very good in 43 of the 48 restorations assessed. The reasons for replacement of the failed restorations were gingival recession (n = 1), restoration fracture (n = 1), core fracture (n = 1), and unknown (n = 2). Each patient's perception of his or her restorations was recorded by means of a questionnaire, with the responses indicating that all but two patients were satisfied. Only one patient had experienced any discomfort.

Direct resin composite inlays/onlays: an 11 year follow-up

OBJECTIVES

The aim of this study was to present an 11-year assessment of direct resin composite inlays/onlays.

METHODS

One-hundred Class II direct resin composite inlays and 34 direct resin composite restorations were placed in 40 patients. The restorations were evaluated clinically, according to modified USPHS criteria, annually over a 11-year period.

RESULTS

Of the 96 inlays/onlays and 33 direct restorations evaluated at 11 years, 17. 7% in the inlay/onlay group and 27.3% in the direct restorations group were assessed as unacceptable. The differences in longevity were not statistically significant. The main reasons for failure for the inlays/onlays and direct restorations were fracture (8.3 and 12. 1%, respectively), occlusal wear in contact areas (4.2 and 6.1%, respectively) and secondary caries (4.2 and 9.1%, respectively). Eight of the non-acceptable inlays/onlays and five of the direct restorations were replaced, while the other ones were repaired with resin composite. Unacceptable wear was observed in occlusal contact areas of six restorations, in patients who were severe bruxers. For the other restorations occlusal wear was not found to be a clinical problem and no difference was observed between the inlays/onlays and direct composite restorations. The marginal adaptation of the inlays/onlays was still good at the end of the study. Ditching was only observed in a few inlays. A higher failure rate was observed in molar teeth than in premolar teeth.

CONCLUSIONS

Good durability was observed for the direct resin composite inlay/onlay technique. Excellent marginal adaptation and low frequency of secondary caries in patients with high caries risk were shown. No apparent improvement of mechanical properties was obtained by the secondary heat treatment of the inlays. Also, the difference in failure rate between the resin composite direct technique and the inlay technique was not large, indicating that the more time-consuming and expensive inlay technique may not be justified. The direct inlay/onlay technique is recommended to be used in Class II cavities of high caries risk patients with cervical marginal placed in dentin.

Evaluation of Carisolv for the chemo-mechanical removal of primary root caries in vivo

The objective of this study was to evaluate a new chemo-mechanical method (Carisolv) for the removal of primary root caries in vivo in terms of efficiency, treatment time and patient perception. Thirty-eight patients participated in an open, randomised and controlled study. Of the 60 root carious lesions included, 34 were randomised for chemo-mechanical treatment and 26 for drilling. A within-subject comparison was used whenever the patient had two cavities, which was the case for 22 subjects. All the Carisolv-treated cavities became caries free, as did all but one of those treated with drilling, as judged by an independent examiner. Only 4 of 34 patients asked for anaesthesia in the Carisolv group compared with 6 of 26 patients in the drilling group. Of those who did not use anaesthesia, 12 individuals in the drilling group experienced some pain compared with none in the chemo-mechanical group (p<0.001). The mean treatment time for the Carisolv method was 5.9+/-2.2 min, compared with 4.5+/-2.0 min for drilling; time for anaesthesia excluded (p<0.05). No negative reactions or adverse effects were recorded during the study. All 55 teeth examined in the 1-year follow-up were found to be sensitive using an electric pulp tester, and there was no difference regarding the condition of fillings between the lesions treated with Carisolv and drilling. It can be concluded that root caries can be effectively removed using the Carisolv method. The longer treatment time was compensated by less need for anaesthesia.

Clinical performance of pressed ceramic inlays luted with resin-modified glass ionomer and autopolymerizing resin composite cements

STATEMENT OF PROBLEM

Several in vitro studies have been published showing the incapability of the chemical cure of dual-cured resin composite luting agents to compensate for absence of visible light activation.

PURPOSE

This study evaluated and compared pairs of Empress ceramic inlays luted with 2 chemical-cured luting agents: a resin-modified glass ionomer cement and a resin composite within individual patients.

MATERIAL AND METHODS

Seventy-nine ceramic inlays were placed in class II cavities in 29 patients. In each patient half of the inlays were luted with a resin-modified glass ionomer cement and the other half with a chemical-cured resin composite cement. The inlays were evaluated clinically, according to modified USPHS criteria, at baseline, after 6 months, and 1 and 2 years.

RESULTS

No failed inlays were observed during the 2-year follow-up. A slight ditching of the cement margins was observed in both luting groups. No significant difference was seen between the 2 luting techniques.

CONCLUSION

IPS Empress inlays luted with both chemical-cured luting agents functioned satisfactorily in the short-term follow-up. Longer observation periods are necessary to evaluate the long-term clinical behavior of both luting techniques.

Ceramic restorations for posterior teeth: guidelines for the clinician

Metal-free ceramic restorations are increasingly popular for restoring posterior teeth. These restorations are generated through a variety of techniques (e.g., CAD-CAM, copy-milling, heat-pressing, and firing). When appropriately indicated and made, ceramic inlays or onlays can be reliable and provide a highly serviceable restoration. The aim of this article is to review and present updated information regarding indications, restorative technique, and maintenance for this class of restorations, with emphasis to fired ceramic inlays or onlays. The information presented is based on 15 years of controlled clinical experience with this category of restorations. Clinical cases that represent some applications also are presented.

CLINICAL SIGNIFICANCE

The fired ceramic inlay/onlay technique is presented as a viable option for the esthetic and adhesive restoration of posterior teeth.