The first thing to consider when factoring the lifespan of a restoration is the bite class of the patient. A restoration in a class I patient with a normal relationship between the upper teeth and lower teeth and a balanced bite will last longer than a restoration placed for a class II or III patient with an abnormal relationship between the teeth and jaw, or other craniofacial structures.
Is the patient a bruxer?
If the patient grinds their teeth, they may already have a history of breaking teeth or dental crowns. If a patient grinds their teeth and isn’t wearing a nightguard, a restoration may break faster than someone else who puts less stress on their teeth on a day-to-day basis. What does the environment of the mouth look like? Everyday use of the mouth and its mechanical factors can impact the life expectancy of a restoration. Things like: occlusion, diet, lifestyle, hygiene, dry mouth, etc. Restorations will have a greater chance for success if the dentist understands the lifestyle habits of patients and can make the proper prescription to meet individual patient needs.
Is the patient looking for esthetics or strength?
When it comes to restorations, there is a tradeoff between esthetics and strength. Materials selection can affect the life expectancy of a restoration, so know what material you’re working with before you start a case. For instance, an all-ceramic crown has more of a tendency to break versus a gold crown or a PFM. If you aren’t sure which material to prescribe for a patient, the lab can look at the margins when the case is mounted to make recommendations.
Are you trying to block out a dark Dentin? A lot of factors can influence the life expectancy of a restoration, and some compromise esthetics for longevity. If you’re trying to block out any Dark dentin or metal posts, your restoration material selection needs to adjust accordingly. What does the tooth preparation look like? If you have small seating on the prep, you need to maximize the space for the best possible restoration. Poor prep design can cause a restoration to fail sooner than expected. Things like: reduction on the occlusal surface, not giving enough room on the prep, jagged margins, buccal lingual walls that aren’t tapered, etc. Be sure to case plan appropriately and correctly prep the tooth to accept the restoration you want.
Z Crown zirconia is intermediate between the strength of BruxZir® and the esthetics of Zirlux®.
Z Crown Anterior is perfect for Anteriors, but strong enough for Posteriors.