Longevity of Direct Dental Restorations

Key Messages

What Is the Issue?

• Direct dental restorations are used to restore teeth affected by dental caries, trauma, wear, or other structural defects with the goal of preserving tooth function, structure, and aesthetics.
• Evidence on the longevity of direct restorations was requested to inform decision-making on replacement intervals.

What Did We Do?

• We conducted a rapid overview of reviews to summarize clinical evidence regarding the longevity of direct dental restorations in permanent and primary teeth using any materials and techniques. We summarized reported factors that affect restoration longevity.

What Did We Find?

• We identified 2 umbrella reviews (URs) and 6 systematic reviews (SRs) that summarized evidence from 107 unique primary reports observing the longevity of direct dental restorations.
• Overall, in permanent teeth, evidence from 1 UR and 5 SRs indicated that cumulative failure rates of restorations generally increased, and success rates decreased, with longer follow-up. Annual failure rates and survival rates of restorations showed no consistent trends over time. Success rates were generally high during the first 3 years after restoration (range, 84.8% to 96.4%) but became more variable from 4 years onward, ranging from 26.1% to 100% at 4 to 6 years, from 62% to 99.1% at 7 to 10 years, and from 43.4% to 95.4% at 11 to 20 years.
• Overall, in primary teeth, evidence from 1 UR and 1 SR indicated that cumulative failure and annual failure rates of restorations generally increased with longer follow-up. Survival and success rates of restorations were not reported. Failure rates reported had wide ranges at 2 years (2% to 60.4%), 3 years (4.9% to 69.1%), and 4 years (13.2% to 26.1%).
• Findings by clinical and restoration characteristics (restoration materials used, location of restorations in the mouth, and type of restorations) were mixed and did not support a consistent longevity associated with follow-up periods.
• For permanent teeth, evidence on relevant factors associated with failure and longevity of direct restorations was available from 1 UR and 5 SRs. They reported:
• restoration longevity is multifactorial, with important contributions from patient caries risk; tooth location and remaining tooth structure; cavity size and complexity; occlusal or mechanical loading; restorative material; adhesive protocol; and clinical technique.
• The principal failure mechanisms were secondary caries, restoration fracture, tooth fracture, marginal degradation, and loss of retention.
• For primary teeth, restoration longevity was mostly influenced by characteristics of the cavity, tooth, restorative material, and operative technique.

What Does This Mean?

• There is no single expected lifespan that applies to all direct dental restorations.
• The evidence base was heterogenous with substantial variation across patient populations, based on which materials and restorative techniques were used, and how outcomes were measured.
• Decision-makers may wish to consider restoration coverage based on restoration complexity, class, and technique; tooth permanency and location; and patient comorbidities and other associated risk factors related to a greater need for restorations.

Research Question

• What is the clinical evidence on the longevity of direct dental restorations?