Avoiding complications in restorative dentistry is essential when providing long-lasting and effective results. Secondary or recurrent caries, in particular, are a significant risk to the success of a restoration, and clinicians must understand how they can be avoided.
The pathogenesis of dentine secondary caries is near identical to any other caries lesion, involving demineralisation and enzymatic dissolution of the organic component. The presence of a restoration or sealant margin makes this a unique issue, distinct from that of primary caries.[i]
Several factors may influence the development of recurrent caries, from restorative material, to the location of restoration gaps, a patient’s caries risk or the experience of the clinician.i Whilst the problem may never be completely eradicated from dentistry, understanding the steps that can be taken to minimise the risk of such complications is key.
The scale of the issue
Dental professionals must understand the extent to which secondary caries plague the success of restorative treatment. One study found that 3.6% of all observed restorations were affected by secondary caries (amongst a sample of 4036 restorations), and at least 20% of patients in the study had at least one secondary caries lesion.[ii] It is the most common diagnosis for restoration failure.[iii]
When a restoration fails, a repair or replacement is needed. A repair may be preferred where at all possible, as it is often quicker and less anxiety provoking for the patient. However, the most important clinical indicator that favours a replacement over a repair is the extent of secondary caries. One study saw that as the depth of recurrent caries increased, a complete replacement was more likely to be carried out in general dental practice. This is likely in an effort to ensure that no caries is left in situ to develop into future problems.iii
Minimising the need for such an intervention will always remain ideal. Clinicians need to choose the appropriate approach for a restoration, including their choice of materials, and provide effective support to high caries risk individuals.
Efforts against caries development
Multiple patient factors can increase the opportunity for recurrent caries to develop. They are, in essence, the same as those for primary caries; oral hygiene, dietary and smoking habits all play a role.ii Clinicians can encourage patients to take up effective dental hygiene routines to minimise the risk of recurrent caries development. Whether they take the advice – such as regular brushing with a fluoridated toothpaste or ceasing a smoking habit – is entirely up to the individual. The profession’s understanding of patient motivation, and thus its efficacy, is developing with time, but clinicians cannot always have control over this aspect of recurrent caries risk reduction.
Clinicians may be able to influence, and reduce, the development of secondary caries through their choice of materials for a restoration. Direct amalgam restorations have been observed to reduce the incidence of caries when compared to composites in some studies,ii however, this often requires tooth or restoration preparation, which may weaken the restored tooth.iii As well as this, patient chair-side time increases.iii In addition, amalgam restorations are considered less aesthetic than composite solutions and with the commencement of the amalgam ban in EU countries come 2025, UK dentists are expected to be hit with disruptions to supply chains and increased costs.[iv]
The predominant alternative at current is glass ionomer cements (GICs). They have good biocompatibility and bind chemically to dental hard tissues, but more importantly, release fluoride which may protect against secondary caries.[v] High viscosity GICs have been noted to protect against secondary caries even in cases of low fluoride compliance.v By choosing such a restorative material, clinicians are opting for a solution that can actively work against secondary caries development whilst the patient is outside the practice, even if the patient does not completely adhere to effective hygiene routines. A GIC will not eliminate the risk of secondary caries development entirely, but its impact can be inarguably effective.
Find your solution
Avoiding secondary caries, and thus invasive repairs and replacements, is no easy feat, but can be achieved with patient compliance and an effective restoration. The choice of material – whether for a direct or indirect restoration – can play a large role.
When a patient needs an indirect restoration, whether it’s a metal crown or bridge, inlay/onlay or all zirconia crown or bridge, clinicians should choose the award-winning* Ketac Cem Plus Resin-Modified Glass Ionomer Cement from Solventum, formerly 3M Health Care. The hybrid glass ionomer cement offers sustained fluoride release, with virtually no post-operative sensitivity for increased patient comfort. The solution is formulated to make everyday procedures faster and more reliable, with a higher bond strength than conventional glass ionomers.
Secondary caries will always be a concern for dental professionals, but by implementing effective materials into the restorative workflow, there is an opportunity to reduce their incidence.
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*Dental Advisor Preferred Product, https://www.dentaladvisorawards.com/products/3m-tm-rely-x-tm-luting-plus (3M Ketac Cem Plus is known as 3M RelyX Luting Plus in some geographies)
About Solventum
At Solventum, we enable better, smarter, safer healthcare to improve lives. As a new company with a long legacy of creating breakthrough solutions for our customers’ toughest challenges, we pioneer game-changing innovations at the intersection of health, material and data science that change patients’ lives for the better while enabling healthcare professionals to perform at their best. Because people, and their wellbeing, are at the heart of every scientific advancement we pursue. We partner closely with the brightest minds in healthcare to ensure that every solution we create melds the latest technology with compassion and empathy. Because at Solventum, we never stop solving for you.
[i] Askar, H., Krois, J., Göstemeyer, G., Bottenberg, P., Zero, D., Banerjee, A., & Schwendicke, F. (2020). Secondary caries: what is it, and how it can be controlled, detected, and managed?. Clinical oral investigations, 24, 1869-1876.
[ii] Nedeljkovic, I., De Munck, J., Vanloy, A., Declerck, D., Lambrechts, P., Peumans, M., … & Van Landuyt, K. L. (2020). Secondary caries: prevalence, characteristics, and approach. Clinical oral investigations, 24, 683-691.
[iii] Javidi, H., Tickle, M., & Aggarwal, V. R. (2015). Repair vs replacement of failed restorations in general dental practice: factors influencing treatment choices and outcomes. British Dental Journal, 218(1), E2-E2.
[iv] British Dental Association, (2023). The amalgam ban: What you need to know. (Online) Available at: https://www.bda.org/news-and-opinion/news/the-amalgam-ban-what-you-need-to-know/ [Accessed May 2024]
[v] Cheng, L., Zhang, L., Yue, L., Ling, J., Fan, M., Yang, D., … & Zhou, X. (2022). Expert consensus on dental caries management. International journal of oral science, 14(1), 17.
