|Year : 2016 | Volume
| Issue : 4 | Page : 233-237
Clinical evaluation of prefabricated ceramic inlays
H Murali1, Ragoothama Rao2, Chirag Bansal2
1 Department of Conservative Dentistry and Endodontics, DAPM RV Dental College, Bengaluru, Karnataka, India
2 Department of Periodontics, DAPM RV Dental College, Bengaluru, Karnataka, India
|Date of Web Publication||27-Dec-2016|
Department of Conservative Dentistry and Endodontics, DAPM RV Dental College, CA 37, 24th Main, JP Nagar 1st Phase, Bengaluru - 560 078, Karnataka
Source of Support: None, Conflict of Interest: None
Background: One of the methods to overcome the problem of polymerization contraction of posterior composites is to use prefabricated ceramic inlays in combination with composites. Several studies have shown that these pre fabricated ceramic inlays act as mega fillers which allow a reduction in resin based composite volume by 50-75% and a concomitant reduction in polymerization shrinkage and marginal micro leakage. Moreover the integration of pre fabricated ceramic inlays into composites reduces the overall coefficient of thermal expansion. Aims and Objectives: The performance of cerena prefabricated inlay system was evaluated. Material and Methods: 20 proximo occlusal cavities were restored with cerana prefabricated inlay system in patients. The performance of cerena pre fabricated inlay system in the oral cavity was recorded at base line follow up using Modified USPHS Ryge criteria at the end of 3, 6, and 12 months. Results: The alpha and Bravo values for the anatomic form, marginal integrity and caries assessment was evaluated. Alpha values were ideal. The Cerena pre- fabricated inlay system showed good fracture resistance, good marginal integrity and maintenance of antomic forms at end of 12 months period. Conclusion: The cerena pre-fabricated inlay system is a good treatment modality and provides a good restorative material at the end of 12 months too.
Keywords: Clinical assessment, prefabricated ceramic inlays, United States Public Health Service Ryge critertia
|How to cite this article:|
Murali H, Rao R, Bansal C. Clinical evaluation of prefabricated ceramic inlays. Indian J Dent Sci 2016;8:233-7
| Introduction|| |
Advances in dental materials have progressively led to many changes in the operative dental techniques. These advances are demonstrated by changes in the preparation design, restoration placement techniques, and improvement in physical properties of the restorative materials. In recent years, resin composites have become more useful as posterior restorative materials. They have the advantage of excellent esthetics relatively low thermal conductivity and preservation of tooth structure in the cavity preparation.
However, posterior composites undergo contraction of between 2.6% and 7.1%.
This results in the formation of gaps as the composite pulls away from the cavity preparation. In addition to these conventional armamentarium, the prefabricated ceramic inlay kit provided by the manufacturers (Cerana, Nordiska Dental Inc., Stockholm, Sweden) contains size-specific rotary diamonds which match with the dimensions of the ceramic inserts. The restoration and dentin tend to expand when subjected to temperature variations in the mouth, increasing the interfacial gap because the coefficient of thermal expansion of composite is different from that of the tooth structure.
Recently, the use of prefabricated ceramic inlays in combination with composites has been recommended to overcome the disadvantages of polymerization shrinkage and poor proximal contacts when using posterior composites.,, Modern insert systems have been available on the dental market since late 1980s. The purpose of this study was to evaluate longitudinally the performance of prefabricated ceramic inlay restorations in vivo over a period of 1 year.
| Materials and Methods|| |
Patients who were selected had vital teeth with indications for Class II inlay restorations on account for repeated failure of direct restoration. Twenty proximo-occlusal cavities were restored with prefabricated ceramic inlay inserts (Nordiska Dental Co., Stockholm, Sweden). The patient age ranged from 18 to 40 years and included both sex. All teeth restored were molars, and cases were selected based on the selection criteria as Class II situations with buccal and lingual walls remaining intact and specific requirements of esthetics were required.
The patients excluded were patients with poor oral prophylaxis where absolute drying using a rubber dam and acid etching was not possible. Patients with very narrow and shallow cavities with a thickness of <2 mm were excluded from the study. Patients included in the study had no parafunctional and bruxism habits.
At the initial examination, patient's medical and dental histories were recorded.
Initial cavity preparations were identical to that of standard Class II cavities for resin composite restorations with minimal extension and rounded internal line angles.
After initial cavity preparation, the cavity was modified using the diamond points supplied by the manufacturer which matched with the prefabricated ceramic inlay [Figure 1].
|Figure 1: Figurative representation of a Class II preparation for a ceramic inlay.|
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The matrix band was applied [Figure 2] wedge placed, and cavity was etched and bonded according to manufacturer's instructions. The cavity was filled to half with a hybrid composite (Filtek 250). Previously selected prefabricated ceramic inlay was removed from the capsule without touching with hands or contaminating the surface, the inlay was placed in the cavity using tweezers. Excess composite which came out of the cavity was removed, and the restoration was light cured for 40 s [Figure 3]. Matrix band and retainer were removed and again the restoration was light cured for 40 s each from buccal and lingual directions. The occlusion was adjusted using articulating paper, and the restoration was finished and polished using polishing kit (Shofu). The prefabricated ceramic inlay inserts were prepolished. Care was taken to see that only minor occlusal adjustments are needed after bonding using conventional ceramic finishing kits. In addition to the conventional armamentarium, the prefabricated ceramic inlay kit provided by the manufacturers (Cerana, Nordiska Dental Inc., Stockholm, Sweden) contains size-specific rotary diamonds which match with the dimensions of the ceramic inserts [Figure 4].
The restorations were evaluated at baseline. Follow-up clinical evaluation was recorded using Modified United States Public Health Service (USPHS) Ryge criteria at the end of 3, 6, and 12 months [Figure 5] and [Figure 6]. The Modified USPHS Ryge criteria  for evaluation of restoration include the evaluation under following criteria.
Alpha: Restoration is continuous with the existing anatomic form; Bravo: restoration is discontinuous with existing anatomic form, but missing.
Material is not sufficient to expose the underlying dentin or base. Charlie: sufficient material is lost to expose dentin or base.
Alpha: No visible evidence of a crevice along the margin or the visible crevice is so small that the explorer just catches but does not “fall in.”
Bravo: Visible evidence of a crevice along the margin into which explorer penetrates but no dentin or the base is exposed.
Charlie: The explorer penetrates into the crevice and dentin or the base is exposed.
Delta: The restoration is fractured or missing in part or in toto.
Alpha: No caries is present at the margins of the restoration.
Charlie: Caries is present at the margin necessitating repair or replacement of the restoration.
| Results|| |
The follow-up clinical evaluation was done at 3, 6, and 12 months using modified USPHS Ryge's criteria. The results were tabulated, statistically analyzed for results as follows.
[Table 1] shows the changes in the anatomic form of the restorations at the end of 3, 6, and 12 months. At the end of 3 months, 18 restorations out of twenty restorations showed alpha values (90%), two teeth out of twenty showed Bravo values discontinuous anatomic form, but missing material was not sufficient to expose dentin (10%).
At the end of 6 months, 11 restorations (55%) showed alpha values and 9 restorations showed Bravo values (45%). At the end of 12 months, 6 teeth showed alpha values (30%) and 14 teeth showed Bravo results (70%).
[Table 2] shows the changes in the marginal integrity of the restorations at 3, 6, and 12 months intervals. At the end of 3 months, 17 restorations out of twenty restorations showed alpha values (85%), three teeth out of twenty showed Bravo values - discontinuous anatomic form, but missing material was not sufficient to expose dentin (15%). At the end of 6 months, ten restorations (50%) showed alpha values and ten restorations showed Bravo values (50%). At the end of 12 months, five teeth showed alpha values (25%) and 15 teeth showed Bravo results (75%).
[Table 3] shows the caries assessment values at 3, 6, and 12 months interval. At 3, 6, and 12 months interval, all the teeth showed alpha values.
In vivo evaluation showed satisfactory results at the end of 12 months period.
Further in vitro and in vivo long-term evaluation with larger sample sizes are needed to substantiate the present study so that this technique can be routinely adopted in clinical practice.
| Discussion|| |
The minimally invasive restoration of primary lesions with composite resin, following the guidelines of the adhesive technique, is an accepted method of treatment today. Data presented in the scientific literature also support the use of resin-based composites for restoring mediumsized Class I and II cavities.
However, clinical shortcomings are associated with the placement of medium-sized Class I and II composite restorations including polymerization shrinkage stresses and differing coefficients of thermal expansion between tooth structure and restorative material, which may both affect marginal adaptation. Furthermore, establishing a physiological proximal contact area is difficult with composite resins, especially in more extended lesions.
Incremental technique was introduced to overcome these shortcomings and to meet the criteria of gap-free marginal adhesion.
Other approaches to improving composite resin materials and adhesive techniques focus upon:
- Further reduction in polymerization shrinkage
- Improvement in bonding techniques
- Improvement and development of curing methods.
In this context, new products such as compomers, ormocers, polyglass, and smart materials have been introduced, curing methods have been modified (soft start technology and plasma arc curing devices), and recently, the use of prefabricated ceramic inserts in combination with composite resins has been advocated for the esthetic and cost-effective restoration of medium-sized Class I and II cavities.,,
In the present study, Cerana prefabricated ceramic inlays were used. Cerana inserts (Nordiska Dental, Ängelholm, Sweden) are manufactured of a translucent leucite-reinforced glass ceramic material which is similar to IPS empress. Leucite has been identified with suitable qualities as a restorative material. Leucite-reinforced porcelain can be employed even in subgingival and supragingival cases, reducing iatrogenic periodontal problems. The dense and regular pattern of leucite crystals prevents the propagation of cracks and thus the extension of fractures. Leucite has high stability in the oral environment, high resistance to acidic foods and solutions, and low tendency to plaque formation. It has no undesired interaction with other dental materials and no chemical decomposition involving the release of decomposition products. The material has a translucency similar to that of enamel and has a wear resistance similar to enamel. An in vitro study was done by us on the same material, and it had shown very promising results in the context of microleakage. This study was done to confirm whether this material lives up to the expectations or not as seen in in vitro study. Shortterm clinical investigations in vivo confirm improvements in the marginal adaptation and increase in wear resistance. Longterm controlled clinical studies are in progress although data are not yet available. Longterm clinical experience is lacking.In vivo studies present very promising results, but predicting the clinical success of this alternative restoration procedure requires further investigations regarding, for example, the stability of the insert/composite bond, the fracture resistance the overall restoration, and wear behavior.
| Conclusion|| |
The cerena pre-fabricated inlay system is a good treatment modality and provides a good restorative material at the end of 12 months too. It maintains the anatomic form, marginal integrity and better caries resistance in the in vivo samples.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2], [Table 3]