|Year : 2014 | Volume
| Issue : 1 | Page : 69-72
Ceramic onlay for endodontically treated mandibular molar
Roopadevi Garlapati1, Bhuvan Shome Venigalla2, Shekhar Kamishetty2, Jayaprakash Thumu1
1 Department of Conservative Dentistry and Endodontics, Sibar Institute of Dental Sciences, Guntur, India
2 Department of Conservative Dentistry and Endodontics, Sri Sai College of Dental Surgery, Vikarabad, Andhra Pradesh, India
|Date of Web Publication||15-May-2014|
Department of Conservative Dentistry and Endodontics, Sibar Institute of Dental Sciences, Takkellapadu, Guntur - 522 509, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Restoration of endodontically treated teeth is important for the success of endodontic treatment. In full coverage restorations, maximum amount of tooth structure is compromised, so as to conserve the amount of tooth structure partial coverage restorations, can be preferred. This case report is on fabrication of a conservative tooth colored restoration for an endodontically treated posterior tooth. A 22-year-old male patient presented with pain in the mandibular left first molar. After endodontic treatment, composite material was used as postendodontic restoration. The tooth was then prepared to receive a ceramic onlay and bonded with self-adhesive universal resin cement. Ceramic onlay restoration was periodically examined up to 2 years.
Keywords: Ceramic onlay, endodontic treatment, post endodontic restoration
|How to cite this article:|
Garlapati R, Venigalla BS, Kamishetty S, Thumu J. Ceramic onlay for endodontically treated mandibular molar. J Orofac Sci 2014;6:69-72
|How to cite this URL:|
Garlapati R, Venigalla BS, Kamishetty S, Thumu J. Ceramic onlay for endodontically treated mandibular molar. J Orofac Sci [serial online] 2014 [cited 2018 Oct 23];6:69-72. Available from: http://www.jofs.in/text.asp?2014/6/1/69/132591
| Introduction|| |
Endodontic treatment is not considered complete until an appropriate permanent coronal restoration is placed. Endodontically treated teeth become brittle and will fracture when subjected to occlusal forces, so they require restorations to provide protection from such injury.  The complete coverage restorations will provide the required protection to ensure the clinical success of the treatment. Some of the studies recommend complete coverage restorations for endodontically treated posterior teeth where much of the tooth strength is lost,  whereas some studies recommend use of complex amalgam restorations and indirect cast restorations to cover the weakened cusps and to preserve the natural tooth structure. 
With the advent of adhesively bonded newer restorative materials with superior esthetics, higher strength, and increased mechanical reliability, the proportion of restorative treatments in endodontically treated posterior teeth using all-ceramics is rapidly growing. 
In cases where the facial and lingual surfaces of an endodontically treated tooth are sound, to conserve the health of the facial and lingual gingival tissues, a partial coverage restoration like an onlay can be designed with adequate resistance form to prevent tooth fracture instead of a full coverage restoration.  Ceramic onlays are excellent esthetic restorations that are often a better alternative than a full coverage crown.
This case report presents the endodontic treatment of a mandibular molar, followed by postendodontic restoration with ceramic onlay with complete cusp coverage and pulp chamber extension and the case was periodically examined.
| Case report|| |
A 22-year-old male patient presented to the Department of Conservative Dentistry and Endodontics, with a chief complaint of continuous and radiating pain in the left lower back tooth since 2 weeks. The medical history was noncontributory. Clinical examination revealed a deep carious lesion in the mandibular left first molar [Figure 1]. The patient complained of episodes of sensitivity to heat and cold in the involved tooth. After detailed clinical and radiographic examination, a treatment plan was suggested as endodontic therapy followed by ceramic onlay with pulp chamber extension and complete cusp coverage in relation to mandibular left first molar. The patient was informed about the procedure.
After administration of local anesthesia, tooth was isolated with a rubber dam and a conservative access opening was prepared. Working length of each canal was confirmed by a radiograph, cleaning and shaping of canals was performed, and the tooth was obturated.
Pulp chamber preparation was done by blocking undercuts in the walls and floor of the pulp chamber using hybrid resin composite (Filtek Z250) [Figure 2]. Before preparing the tooth a preliminary impression was made and a B2 shade was selected using the Vita shade guide.
Ceramic onlay tooth preparation was done as conservatively as possible using crown and bridge preparation kit (Shofu, Crown and Bridge Preparation Kit). Cuspal reduction was done in the form of capping rather than shoeing. Internal angles were made rounded to enhance adaptation of restorative material. Depth orientation grooves are placed on the cusps. 1.5-2.0 mm of occlusal clearance was done to prevent fracture in all excursions. Hollow ground chamfer with no conventional bevel confined to the marginal enamel was placed which aided in developing an effective seal. A distinct heavy chamfer was placed on the facial and lingual surfaces with supragingival margins. Smooth, distinct margins are essential for an accurately fitting ceramic onlay restoration [Figure 3]. Preparation details were recorded with a low viscosity material (Aquasil, Dentsply). Temporary restoration was cemented with a eugenol-free temporary cement. As esthetics is one of the prime concern for the patient, IPS Empress II was selected for the fabrication of the ceramic restoration.
The restoration was carefully positioned to check the marginal adaptation, shape, and shade with complete satisfactory results. The operating field was isolated with a rubber dam.
Following etching, a dentin bonding system was used. Self-adhesive universal resin cement is applied to the restoration and inserted with slight pressure. Excess of cement from the margins was removed with a microbrush. Residual excess cement was removed using explorer and dental floss. Final polishing was achieved using diamond impregnated finishing points and polishing gels [Figure 4]. The patient was periodically reviewed after 6 months, 1 year, and 2 years.
| Discussion|| |
Compared to vital teeth chances of fracture of endodontically treated teeth is higher because of loss of structural integrity associated with dental caries, access cavity preparation, and root canal preparation rather than changes in dentin. 
Endodontically treated teeth require coronal protection to prevent fracture when masticatory forces are delivered on them. Sorensen et al. reported that when maxillary and mandibular premolars and molars were restored with coronal coverage restorations, there was increased success rate. This finding supports that when endodontically treated teeth are restored with full coverage restorations or partial coverage restorations like onlays or complete metal crowns or complete metal ceramic crowns or complete ceramic crowns there was increased longevity of the treated teeth and improved the success rate. 
Partial coverage restorations like gold onlays or ceramic onlays or resin composite onlays and cusp-covering silver amalgam restorations also provide the protection for endodontically treated teeth against fracture. Smales and Hawthorne in their study reported a good survival rate of complex cusp covering silver amalgam partial coverage restorations. 
Conservation, preservation, and reinforcement of tooth structure of an endodontically treated tooth can also be achieved by a partial coverage restoration rather than a full coverage restoration. With the increased demand of tooth colored restorations and improved adhesive techniques, esthetic partial coverage crowns like ceramic crowns can be restored to preserve the maximum amount of sound tooth structure. 
In the present case, endodontically treated mandibular left first molar was restored with a partial coverage esthetic restoration, i.e., IPS Empress II Ceramic Onlay and 2-year clinical performance was evaluated. IPS Empress II all-ceramic material was selected as it exhibits excellent esthetics, has superior wear resistance, and has good bond strength to tooth structure. IPS Empress II is a lithium disilicate ceramic which is developed to increase the strength of the previous ceramics against occlusal stresses.  Clinical studies have proven the higher survival rates for anterior and posterior IPS Empress II crowns. 
Tagtekin et al. evaluated 2-year clinical performance of 28 endodontically treated teeth restored with IPS Empress II Ceramic Onlays and reported that all the restorations performed well up to 2 years of their study. 
In Naeselius et al. 4-year retrospective study of clinical evaluation of all-ceramic onlays, 93% of onlays were still in function after 4 years and concluded that ceramic onlay restorations are acceptable and can be alternative over a 4-year period. 
During restorative procedures, health of the supporting tissues must be carefully observed. In full coverage restorations, margins placed near gingiva may result in gingival overhangs, excessive axial contours, marginal defects, and surface roughness of the restorative material can cause localized gingival inflammation. Unlike the full coverage restorations, the major advantage of ceramic onlay preparation lies in placing the margins of the restoration supragingivally, which are least irritating to the periodontal tissues and finally preserving the biological width. Biological width is important for the preservation of periodontal health and removal of irritants that might damage the periodontal tissues. 
As the onlay preparations are more conservative, most of the tooth structure is preserved during preparation and the time needed for preparation is more less than that needed for a full coverage restorations and placing the supragingival margins causes less damage to the periodontal tissues. But further long-term data are necessary before this treatment to be considered for general dental practice.
| Conclusion|| |
Ceramic onlays are partial coverage restorations which are alternative for restoring endodontically treated posterior teeth in certain clinical situations without interfering with the adjacent periodontal tissues, and not compromising much tooth structure, ceramic onlays satisfy both functional and esthetic demands of patient.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]