Repair may increase survival of direct posterior restorations – A practice based study

Abstract

Objectives

To investigate repairs of direct restorations by a group of Dutch general dental practitioners (GDPs) and its consequences on longevity of restorations.

Methods

Data set was based on dental records of patients attending 11 general dental practices (24 Dentists) in the Netherlands. Patients that received Class II Amalgam or Composite restorations were included in the study. The outcomes were considered in two levels: “Success” – When no intervention was necessary on the original restoration, it was considered clinically acceptable. “Survival” – Repaired restorations were considered clinically acceptable. Kaplan–Meier statistics and Multivariate Cox regression were used to assess restorations longevity and factors associated with failures (p < 0.05).

Results

59,722 restorations placed in 21,988 patients were analyzed. There was a wide variation in the amount of repairs among GDPs when a restoration had failed (Level 1). Repairs of multi-surface restorations were more frequent (p < 0.001). A total of 9253 restorations (Level 1) or 6897 restorations (Level 2) had failed in a 12-year observation time. “Success” and “Survival” of the restorations reached 65.92% (AFR = 4.08%) and 74.61% (AFR = 2.88%) at 10 years, respectively. Patient (age, removable denture) and tooth/treatment-related factors (molars, >2 restored surfaces, endodontic treatment, Amalgam) were identified as risk factors for failure (p < 0.001).

Conclusion

Overall, the GDPs showed satisfactory rates of restoration longevity over 10 years. Repair can increase the survival of restorations although, substantial differences exist among practitioners in repair frequency and AFRs. Molars, multi-surface restorations, presence of an endodontic treatment and a removable denture were identified as risk factors for failure.

Clinical significance

Repair, instead of total replacement of a defective restoration, is a Minimally Invasive procedure which can increase the survival of the original filling, reducing the risk for pulp complications and treatment costs.

Introduction

Placing dental restorations is core business for dentists all around the world. Dental restorations are most commonly placed due to caries or fracture [1], [2] and are often considered as ‘failed’ when a restoration does not meet certain standards that are designed by dental researchers and clinicians [3], [4], [5] or when a patient experiences problems with a restored tooth like pain, unpleasant esthetic appearance etc. In case a restoration has been considered as ‘failed’ and a restorative intervention is needed, there are two possible options. In some cases it is decided to remove the entire restoration which is defined as replacement. Alternatively, only a part of the restoration is removed or a preparation is ground next to a restoration including the outline of the existing restoration. In those cases, the restorative intervention includes an additional restoration, which is defined as repair [6].

Although repair was traditionally often considered as ‘bad dentistry’ and not done by all dentists [7], nowadays repair is more and more considered as state-of-art as it limits the size of the restorative intervention, reduces the risk for complications and limits the costs of the intervention [6], [8], [9]. For indirect restorations, Anusavice et al. [10] defined repaired restorations, as an example due to porcelain fracture or endodontic treatment access opening, not as failures but as survived restorations. Accordingly, an indirect restoration that is still in function without any intervention is considered as a success and only totally replaced restorations (including extractions) are considered as real failures.

For direct restorations, the difference between survival and success is not defined yet in clinical studies as in most longevity studies, any intervention on a direct restoration is considered as failure [11], [12], [13], [14]. Meanwhile, dentists are implementing the concept of repair more and more in their clinical practice [15] and modern dental schools are educating their undergraduates in repair techniques and indications [16], [17], [18], [19], [20].

Longevity of repair restorations, as expressed in the time between the repair restoration and the next intervention, is seldom investigated and includes several studies on interventions on restorations that are not failed yet (B scores for Ryge) [21], [22] showing good survival of small sized repairs. Two studies investigated actually failed restorations placed in some special general practices and demonstrated that repair can increase the longevity of dental restorations [23], [24] while at the same time the longevity of the repair restoration is less compared to the original restoration, depending from material and reason for repair [23].

Although from questionnaires it is known that dentists actually do repairs in their practices, the amount of repairs performed by general dental practitioners and the consequence for restoration survival is not known yet. The present study investigates among a group of general dental practitioners (GDPs) the amount of repairs and its consequences for longevity of class II restorations.