A clinical case by our Community member Dr. Ahmad Al-Hassiny
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Cracked teeth are encountered by dentists daily. The term ‘cracked tooth syndrome’ was first coined by Gibbs in 1954, and the severity and consequences of a tooth fracture can range from minor, needing no treatment at all, to severe, resulting in root canal therapy (RCT), or even tooth loss (1). Many different factors can cause changes in the structural strength of teeth, including the size of a cavity preparation. An common example is large mesioocclusal-distal (MOD) preparations, which often jeopardize the integrity of the tooth by decreasing the amount of sound tooth structure remaining (2). Anytime a tooth is treated with a restoration, the possibility of fracture increases because of reduced supporting tooth structure (3, 4). It is well established in the literature that the more surfaces restored and/or the wider the isthmus, the greater the chance of cuspal fracture (5, 6).
Cracks and fractures associated with large amalgam restorations are therefore common place in general dental practice. Many of these teeth are structurally compromised, and it is common to find evidence of carious lesions beneath these cracks. Not only that, but it is also common to find carious lesions in the adjacent teeth, mesial or distal to the cracked tooth. Especially if the cracks run interproximally.
An adhesive, conservative approach is often the ideal method of restoring these teeth (1). With inhouse CAD/CAM, we can achieve this with a better fit, fewer visits, and much more efficiently than ever before. With the advent of modern ceramics and hybrid materials, we can treat cracked teeth and carious lesions better than ever before. IPS e.Max pioneered this progression and was instrumental in the movement away from PFM. Tetric CAD, a hybrid ceramic material, compliments e.max perfectly in my opinion. It is fast to mill, easy to process, and can be utilized alongside e.max for inlays and onlays. Both materials are made by Ivoclar Vivadent who for the record did not sponsor this article. I am just a fan of their materials and having used them for over 10 years in our practice with great success, I wanted to share a case with you demonstrating this.
This patient presented with a classic representation of the ‘murder house’ days. A quadrant packed full of amalgam fillings, many with surrounding cracks and underlying carious lesions. The plan was to place four indirect restorations, all done in a single visit. The first premolar and second molar were restored with milled inlays using IPS Tetric CAD. The second premolar and first molar were restored with full coverage restorations using IPS e.Max CAD.
Although many materials are coming on the market, there is only one gold standard until proven otherwise. IPS e.Max CAD is my material of choice for 90% of my single-unit ceramic restorations. It is backed up by over ten years of research, and it has been incredibly predictable, aesthetic, and fit for purpose in our clinic.
Fig.1
Pre-operative condition.
Heavily restored and compromised quadrant. Cracks are evident in the first and second molars. Second premolar tooth structure compromised. First premolar failing amalgam restoration.
Fig.2
Existing restorations and caries removed – evidence of carious lesions under all amalgam restorations. Sealing the deepest part of the preparations was carried out.
Fig.3
Intraoral scan carried out with CEREC Primescan. Preparations are marginated, and prep reduction to respect minimum material thickness is checked and confirmed digitally.
Fig.4
Restorations designed using CEREC Primescan. A combination of full coverage and inlay restorations have been fabricated digitally.
Fig.5
An example of the milling process. A Tetric CAD inlay milled out of this restoration block. Note the sprue connection which needs to be removed and polished and is common in all forms of milling.
Fig.6
Two e.max ceramic onlays and two tetric cad inlays. Resin cement was used to bond the restorations – immediate postoperative.
Conclusions
CAD/CAM has revolutionized dentistry. Digital is the future of the profession and provides endless benefits to both dentists and patients. Anyone not adopting digital techniques is falling behind. The use of research-based ceramic materials is the ideal approach to tackle these situations. e.max has been proven time and time again as the gold standard ceramic material. By choosing a suitable material and executing the treatment properly, you will have peace of mind in the long-term outcome of the result.
Bibliography
1. Lubisich EB, Hilton TJ, Ferracane J, Northwest P. Cracked teeth: a review of the literature. J Esthet Restor Dent. 2010;22(3):158-67.
2. Abou-Rass M. Crack lines: the precursors of tooth fractures – their diagnosis and treatment. Quintessence Int Dent Dig. 1983;14(4):437-47.
3. Silvestri AR, Jr., Singh I. Treatment rationale of fractured posterior teeth. J Am Dent Assoc. 1978;97(5):806-10.
4. Udoye CI, Jafarzadeh H. Cracked tooth syndrome: characteristics and distribution among adults in a Nigerian teaching hospital. J Endod. 2009;35(3):334-
5. Cavel WT, Kelsey WP, Blankenau RJ. An in vivo study of cuspal fracture. J Prosthet Dent. 1985;53(1):38-42.
6. Bader JD, Shugars DA, Martin JA. Risk indicators for posterior tooth fracture. J Am Dent Assoc. 2004;135(7):883-92.
