Ceramic Inlays and Onlays: Clinical Procedures for Predictable Results

Ceramic Onlay: A Case Report

With the growing demand for minimally invasive dental restoration, conservative treatment options offer good aesthetic outcomes and durability with minimal tooth reduction. The use of ceramics in dental restoration has been on the rise in the past two decades due to its long-term benefits and capacity to produce a superior bond to tooth structure when used in conjunction with adhesive cement and acid-etch procedures. A ceramic onlay, which covers one or more cusps, also helps to preserve dental tissue. These materials enable the dentist to conservatively prepare the tooth for restoration while also strengthening the patient's own tooth structure. This case report discusses the preparation of a functional and aesthetic ceramic onlay for a patient with a cracked tooth.

Ceramic Inlays: A Case Report

Aesthetic dentistry continues to evolve via advances in bonding agents, restorative materials, and conservative preparation methods. Alternatives to dental amalgam and gold include ceramic dental restorative materials. The lifespan of ceramic inlay repairs is still up for debate. When it comes to durability, colour matching, and anatomical shape stability, ceramic inlay restorations top the list of options. More predictable long-term performance may be achieved by strategically placing ceramic inlays in teeth that are not subjected to significant occlusal stress. Preparation design for ceramic inlay materials is necessary to avoid flexure. This case report discusses the ceramic inlay practice for functional and aesthetic restoration in a patient.

Intrapulpal temperature changes during the cementation of ceramic veneers

Adhesive cementation of ceramic veneers may increase pulpal temperature (PT) due to the combined effect of heat generated by the curing unit and the exothermic reaction of the luting agent (LA). PT increase may induce pulpal damage. The aim was to determine the PT rise during the luting of ceramic veneers (CV) of different thicknesses with light- or dual-curing (LC, DC) adhesive cements as well as pre-heated restorative resin-based composites (PH-RBC). For this a thermocouple sensor was positioned in the pulp chamber of a prepared maxillary central incisor. LC, DC adhesive cements and PH-RBCs heated to 55 °C were used for the luting of CVs of 0.3, 0.5, 0.7, and 1.0 mm thicknesses. The exothermic reaction of LAs added significantly to the thermal effect of the curing unit. PT change ranged between 8.12 and 14.4 °C with the investigated combinations of LAs and ceramic thicknesses (p ≤ 0.01). The increase was inversely proportional to the increasing CV thicknesses. The highest rise (p ≤ 0.01) was seen with the polymerization of PH-RBCs. Temperature changes were predominantly influenced by the composition of the LA, which was followed by CV thickness.

Effect of immediate dentine sealing on the fracture strength of lithium disilicate and multiphase resin composite inlay restorations

PURPOSE

Limited information is available on the effect of Immediate Dentin Sealing (IDS) on the fracture strength of indirect partial posterior restorations. This study evaluated the effect of IDS on the fracture strength and failure types of two indirect restorative materials.

MATERIALS AND METHODS

Standard MOD inlay preparations were made on sound molars (N=40, n=10 per group) and randomly divided into four groups to receive the inlay materials with and without the application of IDS: Group L-IDS-: Li₂Si₂O₅ (Lithium disilicate, IPS e.max) without IDS; Group L-IDS+: Li₂Si₂O₅ with IDS; Group MR-IDS-: Multiphase resin composite (MR, Lava Ultimate) without IDS; MR-IDS+: MR with IDS. Inlays made of L were etched with 5% hydrofluoric acid, and MR inlays were silica coated. After silanization, they were cemented using adhesive resin cement (Variolink Esthetic DC). The specimens were thermo-mechanically aged (1.2×10⁶ cycles, 1.7Hz, 8000 cycles, 5-55°C) and then subjected to load to failure (1 mm/min). Failure types and locations of debondings were classified. Data were statistically analyzed using ANOVA, Mann Whitney U-test and Chi-square tests (α=0.05). Two-parameter Weibull distribution values including the Weibull modulus, scale (m) and shape (0), values were calculated.

RESULTS

After aging conditions, no apparent changes were observed in marginal integrity but occlusal wear facets were more common with MR than with L (p<0.001). Material type and the application of IDS significantly affected the results (p=0.013). While group L-IDS- showed the lowest mean fracture strength (1358±506N) among all groups (p<0.05), application of IDS significantly increased the results significantly (L-IDS+: 2035±403N) (p=0.006). MR groups with and without IDS, did not show significant difference (MR-IDS-: 1861±423, MR-IDS+: 1702±596 N) (p=0.498). When materials without IDS are compared, L showed significantly lower results than that of MR (p=0.035). With the application of IDS, no significant difference was noted between L and MR materials (p=0.160). Weibull distribution presented the highest shape (0) for L-IDS+ (5.66) compared to those of other groups (3.01-4.76). Neither the material type (p=0.830), nor the application of IDS (p=0.54) affected the severity of the failure types. In 95% of the cases, the IDS layer left adhered on the tooth surface after fracture tests. In groups where no IDS was used, resin cement remained on the tooth surface in 44% of the cases (p=0.001). No significant differences were observed between the materials with respect to cement remnants or IDS after fracture (p=0.880). The incidence of repairable failure types (83%) was more common with L than with MR (75%) material (p>0.05).

CONCLUSION

Immediate dentin sealing improves adhesion, and thereby the fracture strength of inlays made of lithium disilicate but not that multiphase resin composite.

Considerations for ceramic inlays in posterior teeth: a review

This review of ceramic inlays in posterior teeth includes a review of the history of ceramic restorations, followed by common indications and contraindications for their use. A discussion on the potential for tooth wear is followed by a review of recommended preparation design considerations, fabrication methods, and material choices. Despite the improved materials available for fabrication of porcelain inlays, fracture remains a primary mode of inlay failure. Therefore, a brief discussion on strengthening methods for ceramics is included. The review concludes with a section on luting considerations, and offers the clinician specific recommendations for luting procedures. In conclusion, inlay success rates and longevity, as reported in the literature, are summarized.

Strength estimation of different designs of ceramic inlays and onlays in molars based on the Tsai-Wu failure criterion

STATEMENT OF PROBLEM

Successful restoration of large molar defects is a serious clinical problem. Studies on the strength of teeth restored with ceramic restorations of various designs have provided conflicting results.

PURPOSE

The purpose of this study was to determine the shapes of large MOD ceramic restorations in molars most likely to prevent failure and to produce a favorable distribution of contact stresses between the cement and teeth during mastication.

MATERIAL AND METHODS

The study was performed using a finite element analysis with contact elements. Eight 2-dimensional models of mandibular first molars with the following designs of MOD ceramic restorations were created: an inlay with a butt joint margin, an inlay with a beveled margin, an onlay with a butt joint margin, and an onlay with a rounded shoulder margin. The restorations had 3-mm or 5-mm isthmus widths. Models of opposing maxillary crowns were also developed. Computational simulation of mastication of boluses in the frontal plane was conducted, during which the stresses occurring in the ceramic restorations, cement, and tooth structure were calculated. The Tsai-Wu failure criterion was used to evaluate the strength of the materials. Contact stresses at the adhesive interface between the tooth structure and resin cement around these restorations were analyzed.

RESULTS

According to the Tsai-Wu failure criterion, the margin of the beveled inlay and the surrounding tissue could be damaged during masticatory simulation. At the junction of the butt joint margin inlay and enamel, contact tensile stresses appeared. The lowest inverse of the Tsai-Wu strength ratio index appeared in the onlay with a rounded shoulder margin. At the adhesive interfaces around margins of large onlays, compressive contact stresses occurred.

CONCLUSIONS

For the large molar MOD ceramic restorations tested, the lowest values of the inverse of the Tsai-Wu strength ratio index and a favorable distribution of contact stresses between restoration and tissues appeared in the onlay with a rounded shoulder margin.

An overview of treatment considerations for esthetic restorations: a review of the literature

Controversy persists regarding the treatment planning criteria for esthetic restorations. This article reviews the literature regarding the biocompatibility, marginal adaptation, color matching, patient selection, technique sensitivity, and mode and rate of failure of tooth-colored restorations. A Medline search was completed for the period from 1986 to 2006, along with a manual search, to identify pertinent English peer-reviewed articles and textbooks. The key words used were amalgam, posterior composite resin, ceramic inlays/onlays, CEREC, porcelain laminate veneers, all-ceramic crowns, and all-ceramic fixed partial dentures.

Maxillary Single-tooth Replacement Utilizing a Novel Ceramic Restorative System: Results to 30 Months

This study reports on the first longitudinal results of an alumina (70%)-zirconia (30%) ceramic restorative system for implant-supported, single-tooth replacement in the anterior maxillary jaw. Eighteen patients (9 men, 9 women, mean age = 42.4 years) were treated with 22 implants placed into 19 extraction sockets and 3 residual ridges. Eight implants were immediately loaded with nonoccluding provisional prostheses. All implants were definitively loaded with fully occluding ceramic restorations after osseointegration and soft tissue maturation. Patients were monitored from 7 to 30 months (mean = 18.1 months) after loading. All implants osseointegrated and were successfully restored. One case of abutment screw loosening occurred because of patient parafunction (bruxing), and another patient reported chewing pain attributed to malocclusion. Both problems were successfully resolved without further incidence. Within the context of this study, single-tooth replacement in the anterior maxillary jaw was successfully achieved with alumina-zirconia ceramic single-tooth restorations with up to 30 months of clinical function.