Survival Analysis of Stainless Steel Crowns in Children with Early Childhood Caries Treated under General Anesthesia

Article information

J Korean Acad Pediatr Dent. 2026;53(1):114-124

Publication date (electronic) : 2026 February 6

doi : https://doi.org/10.5933/JKAPD.2026.53.1.114

Hyejin Jung^1,2,3, Yeonmi Yang^1,2,3, Jaegon Kim^1,2,3, Daewoo Lee^,1,2,3

¹Department of Pediatric Dentistry and Institute of Oral Bioscience, School of Dentistry, Jeonbuk National University, Jeonju, Republic of Korea

²Research Institute of Clinical Medicine, Jeonbuk National University, Jeonju, Republic of Korea

³Biomedical Research Institute, Jeonbuk National University Hospital, Jeonju, Republic of Korea

Corresponding author: Daewoo Lee Department of Pediatric Dentistry, School of Dentistry, Jeonbuk National University, 20, Geonji-ro, Deokjin-gu, Jeonju, 54907, Republic of Korea Tel: +82-63-250-2826 / Fax: +82-63-250-2131 / E-mail: Oklee@jbnu.ac.kr

Funding informationThis work was supported by the Fund of the Biomedical Research Institute, Jeonbuk National University Hospital.

Received 2025 November 25; Revised 2025 December 25; Accepted 2025 December 30.

Abstract

Introduction

Early childhood caries (ECC) is highly prevalent among children under six years of age globally, exhibiting distinct variations across countries and regions, and is strongly influenced by socioeconomic factors[1]. Specifically, severe ECC (S-ECC) not only compromises the quality of life through pain, sleep disturbance, and feeding difficulties but also often necessitates comprehensive treatment of multiple teeth within a short timeframe, making dental general anesthesia (DGA) a commonly selected modality for care[1].

Evidence derived directly from DGA-treated populations supports this approach, indicating that stainless-steel crowns (SSCs) on primary molars demonstrate superior 84-month survival and a longer retreatment interval compared with other restorative materials, including resin composite (RC)[2]. Furthermore, a randomized controlled trial conducted following pulp therapy demonstrated that SSCs provided superior 1-year survival and were more positively received by patients and their caregivers compared with RC[3].

Systematic evidence of the long-term performance of primary tooth restorations consistently confirms that secondary caries is the most frequent cause of failure[4]. Additionally, the clinical performance of tooth-colored restorations on the proximal surfaces of primary molars demonstrates significant variability even at 24 months, depending on the material, moisture control, operator proficiency, and methodology[5]. Unplanned retreatment after DGA may increase due to factors such as restoration failure, recurrent caries, and poor adherence with recall schedules, underscoring the critical importance of selecting appropriate restorative materials for this high-risk population[6].

Clinical reports indicate that material selection is often heterogeneous and influenced by esthetic demands, operator/institutional preferences, and institutional factors[7]. Furthermore, studies examining the risk factors for repeated DGA suggest a complex interplay of behavioral, preventive, and clinical determinants[8]. Given this epidemiologic and clinical background, children with ECC requiring DGA, many of whom inherently face challenges with oral hygiene and remain at high risk for recurrent caries, should be considered strong candidates for SSCs as the primary restorative option to minimize the likelihood of retreatment and re-anesthesia[3-6,8]. Although SSCs and RC are the most commonly used materials for restoring primary molars in clinical practice, domestic studies comparing their survival rates are limited. Specifically, one study reported that flowable RC demonstrated survival rates comparable to those of SSCs for class II primary molar restorations[9]. However, this was based on a general outpatient setting without age restrictions. Currently, no domestic studies have investigated restoration survival rates, specifically targeting patients with ECC treated under DGA. Furthermore, while most international studies analyzing the survival of these two materials under DGA have focused primarily on survival rates, research accounting for complex clinical factors, such as patient age, tooth location, and pulp treatment status, remains extremely limited[2,6]. Therefore, this study aimed to compare long-term survival rates and identify risk factors for SSCs and resin restorations in patients with ECC who underwent dental treatment under DGA.

Materials and Methods

Results

2. Survival Probability

Kaplan-Meier analysis demonstrated significantly higher survival for SSC restorations than for resin restorations throughout the follow-up period (log-rank p < 0.0001; Fig. 1). At 12, 24, and 36 months post-DGA, the survival rates for resin were 83.8%, 59.2%, and 46.1%, respectively, whereas survival for SSCs was 95.7%, 92.2%, and 89.4%, respectively (Table 1). At 84 months, survival declined to 21.8% for RC and 80.6% for SSCs.

Fig 1.

Kaplan-Meier survival analysis of resin restoration and stainless steel crown.

Table 1.

Survival probability of resin restorations and stainless steel crowns

3. Risk Factors for Failure

Cox proportional hazards modeling identified restorative material as the dominant predictor of failure (hazard ratio [HR] = 8.573, 95% confidence interval, 5.04 – 14.60), p < 0.0001 (Table 2). Other covariates, including sex, age group, disability, systemic disease, tooth type, pulp therapy status, and frequency of visits, were not significantly associated with restoration survival in the full cohort.

Table 2.

Risk factors affecting restoration failure

In the SSC sub-analysis, no covariates demonstrated a significant association with failure (Table 3).

Table 3.

Risk factors affecting stainless steel crown failure

In the resin sub-analysis, the failure risk was significantly related to age and tooth type, with inferior outcomes in younger children and mandibular first primary molars (Table 4). In the stratified Kaplan-Meier curves for resin restorations, mandibular first primary molars exhibited the worst survival (Fig. 2).

Table 4.

Risk factors affecting resin restoration failure

Fig 2.

Kaplan-Meier survival analysis of resin restoration according to tooth type.

4. Reasons for Failure and Retreatment Patterns

Secondary caries was the most common cause among the 132 restoration failures (Table 5). Material-specific patterns were distinct; 83.7% of failed resin restorations were attributable to secondary caries, whereas 50% of failed SSCs were due to inflammation (Table 5). Restoration loss and fracture accounted for 12.1% of all failures, while early exfoliation accounted for 5.3%. Retreatment pathways varied according to restorative material (Table 5). Following resin failure, the most common approaches were restoration with resin (36.7%) or conversion to SSC (36.7%). After SSC failure, extraction (26.5%), pulpectomy (23.5%), and recementation (23.5%) were common, whereas SSC replacement was rare (2.9%).

Table 5.

Comparison of failure reasons and retreatments between resin restorations and stainless steel crowns

Discussion

This retrospective cohort study of patients with ECC treated under DGA demonstrated that SSCs achieved significantly higher long-term survival than RC. The HR indicated that resin restorations were more than eight times more likely to fail than the SSC restorations. This effect persisted after accounting for patient- and tooth-level covariates, indicating that the restorative material was the dominant determinant of longevity in this high-risk setting.

These findings diverge from those of some outpatient reports, in which resin restorations demonstrated acceptable survival under specific clinical indications. For instance, a domestic study reported that flowable RC demonstrated survival rates comparable to those of SSCs for class II primary molar restorations[9]. However, the study was based on outpatient care. Our findings converge with the DGA-specific evidence reporting superior survival or longer retreatment-free intervals for SSCs[2,6,8,10]. This discrepancy underscores that the favorable outcomes of resin restorations observed in cooperative outpatient settings may not translate to the DGA population, where high caries risk and challenges in oral hygiene maintenance are prevalent.

In addition, the present findings should be interpreted within the specific context of high‑risk ECC children treated under dental general anesthesia, in whom multiple primary molars frequently exhibit extensive structural loss and suboptimal moisture control. In outpatient or lower‑risk settings where cavity form can be thoroughly evaluated, isolation is predictable, and lesion extent is limited, resin composite restorations may still be appropriate for selected conservative preparations, particularly when esthetic demands are substantial. Thus, although SSCs demonstrated superior longevity despite being placed in more severely compromised teeth in this cohort, these results do not indicate that SSCs should uniformly replace resin in all clinical situations; rather, they support prioritizing SSCs as the default option in comparable high‑risk DGA populations while permitting carefully selected use of resin composite in well‑indicated cases.

A notable finding of this study was the consistent stability of SSCs irrespective of patient-level systemic factors. The Cox proportional hazards model revealed that sex, age, disability status, and systemic disease were not significant predictors of restoration failure in the full cohort. This suggests that the profound influence of the restorative material (SSC vs. resin), as the dominant determinant of longevity, overshadows the effects of patient-related systemic factors. This finding is critical, as it indicates that the superior performance of SSCs persists irrespective of patient comorbidities, reinforcing their role as a reliable, first-line restorative option for the heterogeneous, high-risk ECC population undergoing DGA.

Furthermore, SSCs exhibited consistent stability regardless of the pulp therapy status. This aligns with randomized data favoring full coverage after pulp therapy in primary molars, with our finding that pulp therapy status was not a significant predictor of failure, reinforcing this concept[3,11]. Notably, the robust survival of SSC appears largely independent of whether definitive pulp therapy is performed, emphasizing that the comprehensive coronal coverage (SSC), rather than the presence of internal treatment alone, is the key determinant of restoration longevity. In contrast, approximately half of the resin restorations failed by 36 months, with failure clustering in younger children and mandibular first primary molars, a distribution consistent with the findings of the prior studies identifying age and molar type as meaningful covariates of resin performance in primary teeth[12-14].

The failure patterns observed in our cohort are consistent with those reported in the literature: secondary caries predominated overall, especially for resin, which is consistent with systematic evidence identifying recurrent caries as the leading cause of failure in primary tooth restorations[4,15]. Conversely, SSC failures were infrequently attributable to secondary caries, with inflammation accounting for 50% of SSC failures in our study. The inflammation observed in SSC-restored teeth, especially those that have undergone pulp therapy, reflects the failure of the underlying endodontic procedure rather than the SSC. However, the extremely low rate of secondary caries (only 2.9% in SSC failures) strongly demonstrates that the SSC successfully performs its primary function as a robust coronal seal, effectively protecting the tooth from the oral environment[16]. Therefore, the observed failure mode of apical pathology is more likely a reflection of the biological limitations and prognosis of the severely compromised tooth—the underlying condition that necessitated DGA—rather than a deficiency of the restorative material. In the context of a DGA cohort aimed at minimizing retreatment and re-anesthesia, any event that necessitates further intervention represents a failure of the overall long-term restorative strategy.

Importantly, 36.7% of failed resin restorations were converted to SSCs during retreatment, reflecting a common clinical trajectory: even when resin is initially attempted, treatment often progresses to full-coverage solutions. Together with evidence that unplanned retreatment following DGA is primarily associated with restoration failure and recurrent caries, and that minimizing repeat DGA is a key patient safety and quality objective, our findings provide practice-based justification to prioritize SSCs as the first-line restorative option for children with ECC requiring GA[6,8,17,18].

The strengths of this study include a focused DGA cohort, a decade-long follow-up, and analysis of the causes of failure and survival. These limitations are inherent to the retrospective, single-center design. Specific cavity classifications and the number of affected surfaces were not included in the analysis. However, this limitation strengthens our conclusion regarding the superiority of SSCs. In general clinical practice, RCs are selected for smaller, more conservative lesions, whereas SSCs are indicated for extensive multi-surface caries with greater structural loss[7,19]. This suggests the presence of an inherent selection bias, where the SSC group likely comprised teeth with more severe initial destruction than those in the resin group. The fact that SSCs demonstrated significantly superior longevity despite being utilized for more compromised cases further validates the structural robustness of full-coverage restorations and confirms their resilience even when challenged with extensive tooth loss in this high-risk population.

In addition to these design constraints, the interpretation of longevity in this cohort also depends on how failure was defined and ascertained. The definition of failure used in this study focused on events that required active clinical intervention—such as restoration loss or fracture, radiographic or clinically evident recurrent caries, signs or symptoms of apical inflammation, or other functional problems leading to retreatment. Physiologic root resorption and exfoliation at an age-appropriate stage were not regarded as failures unless tooth loss occurred prematurely and required unplanned management. Discoloration or minor surface wear without a need for restorative intervention was not classified as failure and was not coded as an event in the survival analysis. This pragmatic, treatment-based definition aligns with the primary aim of DGA care to minimize subsequent interventions and repeat anesthesia, but it may underestimate minor deterioration that does not trigger retreatment. Future prospective studies incorporating standardized clinical indices for integrity, color, and surface quality could provide a more nuanced assessment of material performance beyond the need for retreatment alone.

As repeat anesthesia has patient safety, caregiver burden, and cost implications, system-level policies that facilitate access to SSCs are warranted for high-risk ECC populations[20,21]. Future studies should standardize procedural variables, such as restoration materials and techniques, and incorporate long-term follow-up outcome measurements to enhance clinical evidence.

Conclusion

This retrospective study confirmed that SSCs offer significantly superior long-term longevity compared with RC restorations in children with ECC treated under DGA. In contrast, resin restorations were prone to failure, primarily due to secondary caries in younger patients and mandibular first primary molars. SSCs demonstrated robust stability that was not influenced by patient-level systemic covariates or concomitant pulp therapy. Given the frequent need to convert failed resin restorations to crowns, SSCs should be prioritized as the standard of care for primary molars in this high-risk population. Adopting this strategy is essential to ensure predictable clinical outcomes and to minimize the burden of retreatment and repeated DGA. These findings should not be generalized to all clinical scenarios, particularly outpatient or lower‑risk settings where cavity form, lesion extent, and esthetic priorities may reasonably favor resin composite restorations for conservative preparations. Rather, the results support prioritizing SSCs as the standard of care for primary molars in comparable high‑risk ECC patients requiring DGA, to ensure predictable outcomes and to minimize the burden of retreatment and repeated anesthesia.

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