Health Technology Review

Longevity of Direct Dental Restorations

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 heterogeneous 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?

Context and Policy Issues

What Are Dental Restorations?

Direct dental restorations are restorative procedures in which dental materials are placed, shaped, and hardened directly in the patient’s mouth.¹ These procedures are commonly used to restore teeth affected by dental caries, trauma, wear, or other structural defects with the goal of preserving tooth function, structure, and aesthetics. Direct restorations are widely used because they are generally less invasive, require fewer appointments than indirect restorations, and can preserve more natural tooth structure.

Several materials are used for direct restorations, such as resin composites, glass ionomer cement (GIC), resin-modified GIC (RMGIC), compomers, and, historically, dental amalgam.¹ In addition to the material used, tooth location and cavity class also influence technical complexity, exposure to biting forces, and longevity of direct restorations.^2,3 Anterior restorations involve incisors and canines, posterior restorations involve premolars and molars, and cervical restorations are located near the gumline.^2,3 Class I restorations involve pits and fissures; class II restorations involve the proximal surfaces of posterior teeth; and classes IV and III involve the proximal surfaces of anterior teeth, with and without involvement of the incisal edge, respectively. Class V restorations involve the cervical third of anterior or posterior teeth.

Although direct dental restorations are intended to provide long-term function, they may require repair, replacement, or other clinical interventions over time.^4,5 This can happen because of material degradation, recurrent caries, fracture, wear, or other complications.^4,5 Direct restorations represent a substantial component of routine dental care. They may contribute considerably to oral health expenditures because of their high utilization and the need for repair or replacement over time.⁴

Longevity of Direct Dental Restoration

There is no single expected lifespan that applies to all direct restorations.^6,7 Restoration longevity can be influenced by multiple factors, including restorative material, restoration type and location, tooth characteristics, patient-level factors, clinical techniques, operator experience, follow-up duration, and the outcome definitions used.^6,7 Consequently, longevity estimates can vary substantially across studies and clinical settings.

Longevity should be interpreted separately for primary and permanent teeth.⁸ Restorations in primary teeth are generally expected to remain functional until the tooth naturally exfoliates; therefore, their clinically relevant lifespan and available follow-up are inherently limited by the remaining life of the tooth.⁹ Treatment selection may consequently consider the expected time to exfoliation, in addition to the child’s age, caries risk, cavity size, and ability to tolerate treatment.^8,9 In contrast, permanent teeth are expected to remain functional throughout adulthood, making longer-term restoration survival, repeated re-interventions, preservation of remaining tooth structure, and the cumulative risk of more extensive treatment particularly important.⁸

Evidence on restoration longevity is commonly reported using cumulative failure, survival, or success rates at specified follow-up intervals, annual failure rates (AFRs), or time-to-event measures such as median survival time.¹⁰ Failure rate over a specified follow-up period represents the cumulative proportion of restorations that failed during that period. An AFR represents failure as an average rate per year.¹⁰ Survival generally refers to a restoration remaining in service until a predefined failure event, such as replacement or tooth loss, whereas success reflects the absence of clinically relevant deficiencies and may capture restorations requiring repair or other interventions before complete failure.¹¹ Some studies also used terms such as minor failure, in which the restoration was either repaired or refurbished through polishing or adjustment, or major failure, in which the restoration required complete replacement.¹²

Direct Dental Restoration in Canada

In Canada, direct dental restorations are among the most performed dental procedures to restore affected teeth. Resin composites and dental amalgam have been the most frequently used restorative materials, although the use of amalgams has declined in recent years.^13,14 GIC and RMGIC restorations are also used in selected clinical situations.¹⁵ Evidence on time to re-intervention in the context of Canada is limited but suggests that many restorations remain in service considerably longer than 2 years.^16,17 However, the findings are not nationally representative, and comparable evidence for most restorative materials is lacking in the context of Canada.

Why Is It Important to Do This Review?

Re-interventions, including repair, refurbishment, replacement, or more extensive restorative treatment, represent a substantial proportion of routine dental care and contribute considerably to the long-term costs and burden of restorative treatment.^4,11 decision-makers remain uncertain about the expected longevity of direct dental restorations. Evidence on the longevity of direct restorations will inform clinical decision-making, reimbursement policies, and program planning, particularly in contexts in which replacement intervals and eligibility criteria are considered. There is a need to synthesize evidence from studies evaluating the longevity of direct dental restorations for people undergoing these restorations.

Objective

In response to an external request to support decision-making about appropriate timelines for re-intervention after direct dental restorations, we prepared this rapid overview of reviews to summarize and critically appraise available evidence regarding the longevity of direct dental restorations. This review also summarizes the most relevant factors affecting restoration failure and longevity.

Methods

An information specialist conducted a customized literature search of multiple sources and grey literature, balancing comprehensiveness with relevance, on July 17, 2026.

One reviewer screened citations and selected studies based on the inclusion criteria presented in Table 1 and critically appraised included publications using 1 critical appraisal tool.¹⁸

Appendix 1 presents a detailed description of methods and selection criteria for included studies.

Table 1: Selection Criteria

Summary of Evidence

Quantity of Research Available

Eight publications^12,19-25 met our inclusion criteria, including 6 systematic reviews (SRs) and 2 umbrella reviews (URs). A UR is an SR of SRs or meta-analyses. We reported on the characteristics and results from the subset of relevant studies. Appendix 2 presents the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA)²⁶ flow chart.

Summary of Study Characteristics

Appendix 3 provides details regarding the characteristics of included publications.

Clinical Evidence on the Longevity of Direct Dental Restorations

Study characteristics demonstrated substantial variation across a large evidence base, including differences in restoration materials and types, clinical techniques, outcome definitions, evaluation criteria, and follow-up duration. Information on outcomes across different population groups was limited.

General Characteristics

The 2 URs^23,24 synthesized evidence from 22 SRs relevant to this report and the 6 SRs^12,19-22,25 included data from 107 unique primary studies relevant to this report. Some overlap was identified among the primary studies included in the SRs, whereas no overlap was identified among the SRs included in the URs. There was no overlap in primary studies of SRs^12,19,20 reporting pooled estimates or meta-analysis (refer to Appendix 6 for details regarding overlap).

Overall, 3 SRs^12,22,25 and 2 URs^23,24 reported no publication date restrictions, and the most recent search date reported among the included publications was March 2025.²³ Studies included in the 6 SRs^12,19-22,25 were conducted across 32 countries. The most frequently represented countries were Brazil (n = 17), the Netherlands (n = 12), the UK (n = 12), Türkiye (n = 11), Sweden (n = 8), and Germany (n = 6). One included primary study reported in 1 SR²¹ was conducted in Canada. Country information was not reported in the 2 URs.^23,24

Population Characteristics and Study Settings

The included publications varied in the level of detail reported for study population characteristics. Two SRs^12,20 and 2 URs^23,24 reported age information. One UR²³ included participants ranging from young adults to adults aged older than 80 years, whereas 2 SRs^12,20 reported mean ages ranging from 26.7 to 81.5 years. Another UR²⁴ focused on children aged up to 12 years. Participant numbers were reported in 4 SRs and ranged from 15 to approximately 3 million participants across included primary studies.^20-22,25

Two SRs^20,25 provided information on the sex of participants from their included primary studies; the authors did not report how sex had been defined or measured. Two SRs^20,25 reported on the range of female and male participants; other sexes or genders were not reported. None of the included reviews^12,19-25 reported information on other PROGRESS-Plus characteristics,²⁷ such as place of residence, race, ethnicity, culture, language, occupation, religion, education, socioeconomic status, and social capital.

Settings were reported in 5 included reports^{12,20,21,23,25} and included university clinics (2 SRs^12,21 and 1 UR²³), controlled academic environments (1 UR),²³ general and private dental practices (3 SRs^12,21,25 and 1 UR²³), clinics and outreach programs (1 SR),²⁰ schools (1 SR),²⁵ and special care or nursing home settings (1 UR).²³

Clinical Indications and Interventions

The 8 reviews^12,19-25 included populations receiving direct restorations in both permanent and primary teeth across a range of clinical indications. Permanent teeth populations included patients undergoing direct restorations (1 UR),²³ adults with pathological tooth wear (1 SR),¹² adults with root caries lesions (1 SR),²⁰ patients receiving multisurface posterior restorations (1 SR),¹⁹ patients receiving anterior restorations (1 SR),²² and broader populations of children, teenagers, and adults receiving restorations (1 SR).²¹ Primary teeth populations included children with deep carious lesions in primary teeth (1 UR)²⁴ and children with previously unrestored carious lesions in primary teeth (1 SR).²⁵

The reviews evaluated a wide range of direct restorative interventions, including:

• materials:

  • composite materials:

    • resin composites (6 SRs^12,19-22,25 and 2 URs^23,24)

    • bulk-fill composites (1 SR²⁵ and 2 URs^23,24)

    • ormocer (organically modified ceramic)–based composites (1 UR)²³

  • glass ionomer–based materials:

    • GICs (2 SRs^20,25 and 2 URs^23,24)

    • RMGICs (2 SRs^20,25 and 2 URs^23,24)

    • high-viscosity GICs (HVGICs) (1 SR²⁵ and 1 UR²⁴)

    • metal-reinforced GICs (MRGICs) (1 SR²⁵ and 1 UR²⁴)

    • glass carbomers (1 SR)²⁵

  • other restorative materials:

    • compomers (1 SR²⁵ and 1 UR²⁴)

    • amalgam (2 SRs^19,25 and 2 URs^23,24)

• techniques and strategies:

  • adhesive approaches (1 SR²² and 2 URs^23,24)

  • sandwich techniques (2 URs)^23,24

  • atraumatic restorative treatment (2 SRs^20,25 and 1 UR²⁴)

  • Hall technique (1 SR)²⁵

  • pulpotomy (1 UR)²⁴

  • selective or complete caries removal (1 SR)²⁵

• restoration types and locations:

  • class I to V restorations (2 SRs^22,25 and 2 URs^23,24)

  • anterior (3 SRs)^12,21,22 and posterior restorations (3 SRs^12,19,25 and 1 UR²⁴)

  • multisurface restorations (1 SR¹⁹ and 1 UR²⁴)

  • root caries lesions (1 SR)²⁰

  • tooth wear lesions (2 SRs)^12,22

  • noncarious cervical lesions (NCCLs) (1 UR)²³

  • restorations in both primary (1 SR²⁵ and 1 UR²⁴) and permanent dentitions (5 SRs^12,19-22 and 1 UR²³).

Outcomes and Follow-up

Commonly reported outcomes related to restoration performance in the reviews included restoration survival rates (4 SRs^12,19,21,22 and 1 UR²³); restoration success rates (3 SRs^12,20,21 and 1 UR²⁴); restoration failure rates, AFRs, or treatment failure (4 SRs^12,21,22,25 and 2 URs^23,24); reasons for restoration failure (5 SRs);^19-22,25 and factors associated with restoration outcomes (1 UR).²⁴ All reviews^12,19-25 reported outcomes at follow-up, with follow-up durations ranging from 6 months to 30 years across the included reviews.

Summary of Critical Appraisal

Overall, the methodological quality of the included reviews was mixed. Three SRs^12,19,25 and 2 URs^23,24 adequately reported relevant details across most critical domains in A MeaSurement Tool to Assess systematic Reviews, version 2 (AMSTAR 2).¹⁸ In contrast, 3 SRs^20-22 did not meet, or partially met, several critical AMSTAR 2 domains. ¹⁸ Appendix 4 provides additional details about the strengths and limitations of the included publications.

Approaches to review planning and the selection of eligible study designs differed across the included reviews. The authors of 2 URs^17,18 and 4 SRs^12,19,22,25 established their methods before conducting the review through prospective protocol registration, reducing the risk of selective reporting and post hoc methodological decisions. In contrast, 2 SRs^20,21 did not report protocol registration or an a priori protocol. All reviews had explanations of the study designs selected for inclusion except for 1 SR,²² which identified included study designs but did not provide a justification for their selection.

Methods used to identify relevant literature varied across reviews and may have influenced the scope of studies included. All 8 reviews^12,19-25 searched multiple bibliographic databases and reported search strategies or search terms. However, 6 SRs^12,19-22,25 and 1 UR²³ lacked 1 or more components of a comprehensive search strategy, such as grey literature searches, trial registry searches, or consultation with experts, which may have increased the risk of publication bias and omission of relevant evidence. In contrast, the authors of 1 UR²⁴ conducted a more comprehensive search that included grey literature and clinical trial registries. The authors of 2 URs^17,18 and 3 SRs^12,22,25 did not apply publication date restrictions, whereas the authors of 3 SRs^19-21 restricted inclusion by publication year; these restrictions were justified by the review authors and were intended to capture contemporary or clinically relevant evidence. The authors of 2 URs^23,24 and 2 SRs^12,25 reported no language restrictions, whereas 3 SRs^19,20,22 included only English-language studies, which may have introduced selection bias and excluded relevant evidence published in other languages. Language restriction was not clearly reported in 1 SR.²¹

The conduct and transparency of key review processes varied across the included reviews. Study selection was conducted independently by at least 2 reviewers with disagreements resolved through discussion or involvement of an additional reviewer in 2 URs^23,24 and 4 SRs.^12,19,21,25 Data extraction was independently verified or conducted by at least 2 reviewers in 2 URs^23,24 and 2 SRs.^12,25 These practices may reduce the risk of reviewer bias and data extraction errors. One UR²⁴ provided a comprehensive list of excluded studies with reasons for exclusion. The remaining reviews reported exclusions through PRISMA flow diagrams or general exclusion categories, limiting the transparency and reproducibility of the review process.

Approaches to risk of bias assessment differed across reviews. The authors of 2 URs^23,24 and 4 SRs^12,19,20,25 assessed study quality or risk of bias using structured appraisal tools and considered these findings when interpreting their results. In contrast, the authors of 2 SRs^21,22 did not perform formal risk of bias assessments of included studies, limiting assessment of the internal validity of the evidence. Although 1 SR²⁰ assessed study quality, it did not use a risk of bias tool specific to the appraisal of RCTs, evaluate the impact of study quality on pooled estimates, or formally assess publication bias despite conducting meta-analyses.

Evidence synthesis methods, assessment of heterogeneity, and evaluation of publication bias were generally appropriate when quantitative synthesis was performed. The authors of 2 SRs^19,20 who conducted quantitative synthesis used appropriate statistical methods to pool data and assess heterogeneity. The authors of 1 SR¹⁹ assessed heterogeneity using I² statistics, whereas the authors of another SR²⁰ explored heterogeneity through meta-regression analyses. Two URs^17,18 and 5 SRs^{12,19,20,22,25} included discussions of clinical and methodological heterogeneity arising from differences in restorative materials, interventions or restorative approaches, study designs, outcome definitions, evaluation criteria, follow-up duration, patient factors, and failure criteria. In contrast, the authors of 1 SR²¹ described variability among studies but did not formally investigate or explain heterogeneity. The substantial clinical and methodological heterogeneity reported across studies may limit the direct applicability of findings to specific clinical settings, including current dental practice in the context of Canada. Of the 2 SRs^19,20 that included quantitative synthesis, publication bias was formally assessed in 1 SR.¹⁹ The absence of publication bias assessment in the other SR²⁰ may limit confidence in the pooled findings.

Finally, reporting of study characteristics and funding varied across the evidence base. The authors of 4 SRs^12,20,21,25 and 1 UR²³ adequately described the characteristics of included studies, including populations, interventions, comparators, outcomes, study designs, settings, and follow-up periods. However, the authors of 1 UR²⁴ and 2 SRs^19,22 did not consistently report study-setting information. Information on equity-relevant population characteristics, such as socioeconomic status, ethnicity, geographic location, and other PROGRESS-Plus characteristics,²⁷ was generally limited across all reviews,^12,19-25 restricting assessment of the generalizability of findings to populations that may experience differences in oral health outcomes or access to dental care. Funding sources for included primary studies were reported in 1 SR²⁵ and 1 UR,²³ limiting assessment of the potential influence of funding bias on the evidence base.

Summary of Findings

Appendix 5 presents the main study findings.

Clinical Evidence on the Longevity of Direct Dental Restorations

Across the included evidence, restoration longevity varied substantially by restorative materials, tooth locations, cavity types, outcome definitions, and follow-up periods.

Clinical evidence regarding the longevity of direct dental restorations was available from 2 URs^23,24 and 6 SRs.^12,19-22,25 The authors of 3 SRs^12,19,20 and 1 UR²⁴ provided meta-analysis or pooled mean estimates of the outcomes relevant to our review. There was some overlap in the primary studies included in the 6 SRs^{12,19‑22,25} and no overlap in the SRs included in the 2 URs;^23,24 there was no overlap in primary studies of SRs^12,19,20 reporting pooled estimates or meta-analyses (Appendix 6). The authors of 1 UR²³ and 5 SRs^12,19-22 reported results on various types of direct restorations in permanent teeth, whereas the authors of 1 UR²⁴ and 1 SR²⁵ reported results on direct restorations in primary teeth.

Permanent Teeth

The authors of 1 UR²³ and 5 SRs^12,19-22 evaluated the clinical evidence on the longevity of direct dental restorations in permanent teeth. Table 2 summarizes the outcomes regarding the longevity of direct dental restorations in permanent teeth based on years of follow-up. The ranges reported in this table combine results across all materials, restoration classes, techniques, and tooth locations reported in the evidence related to permanent teeth. Considerable variation in restoration failure rates, AFRs, success, and survival rates reflects differences in materials, cavity classes, techniques, evaluation criteria, and study populations. The findings related to direct restorations using amalgams were excluded from this table.

Overall, outcomes varied widely across follow-up periods. 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. Restoration survival rates also varied substantially at longer follow-up, while AFRs ranged from near 0% to approximately 25%. Overall, the evidence suggests greater variability and some deterioration in outcomes with longer follow-up, although no consistent time-related trends were observed across all measures.^12,19-21

Table 2: Summary of Findings for the Longevity of Direct Dental Restorations in Permanent Teeth Based on Years of Follow-up

AFR = annual failure rate; nRCT = nonrandomized controlled trial; NR = not reported; RCT = randomized controlled trial; SR = systematic review; UR = umbrella review.

Findings by Clinical and Restoration Characteristics

Resin Composites

The authors of 1 UR²³ and 4 SRs^12,19-21 evaluated the clinical evidence on the longevity of direct dental restorations using resin composites (Table 13). The overall restoration failure rates ranged from 3% to 43%, AFRs ranged from 0 to 25%, restoration survival rates ranged from 23% to 100%, and success rates ranged from 26.1% to 100% at follow-ups ranging from 1 to 30 years in permanent teeth. Longevity of direct dental restorations using resin composites varied based on location in the mouth:

• Posterior teeth (1 UR²³ with 6 relevant SRs, 1 SR²¹ with 14 relevant RCTs, and 1 SR¹⁹ with 4 relevant meta-analyses):

  • Restoration failure rates generally increased with longer follow-up, from approximately 3% to 5.2% within 3 to 5 years, to 14% at 6 to 10 years, 20% at 11 to 15 years, and 43% after at least 15 years.

  • AFRs did not increase consistently with follow-up; most estimates were approximately 1% to 5% per year, with a few higher estimates.

  • Restoration survival and success estimates varied considerably between studies, ranging from 23% to 100% and 26.1% to 100%, respectively.

• Anterior teeth (1 SR²² with 13 relevant RCTs, 1 SR²¹ with 4 relevant RCTs, and 1 SR¹² with 2 relevant pooled estimates):

  • AFRs based on individual RCTs ranged from 0% to 5% per year, although the pooled analyses showed wider ranges, particularly for minor restoration failures (i.e., 0% to 8.76%).

  • Major and minor restoration failures were reported in 1 SR;¹² major AFRs were generally lower than minor AFRs, indicating that minor deterioration was more common than catastrophic restoration failure.

  • Restoration success rates were generally high during the first 5 years, but they tended to decrease with longer follow-up, reaching approximately 62% to 81.5% at 10 years and 66.5% to 74.4% at 14 to 15 years. This pattern was not consistent across all studies.

• Cervical regions (1 UR²³ with 2 relevant SRs and 1 SR²³ with 5 relevant RCTs):

  • NCCL restorations had a cumulative failure rate of 22.8% to 27.9% at 3-year follow-up.

  • AFR estimates ranged from 1.82% to 4.6% per year over 6 to 10 years.

  • Restoration survival rates ranged from 72.4% to 88.2% at 6 years and 74.7% at 22-year follow-up.

  • Long-term success rates ranged from 74% to 88% at 13 to 15 years.

• Root caries (1 SR²⁰ with meta-analysis) reported a success rate of 96.3% at 1-year follow-up.

The longevities of direct dental restorations using resin composites for different restoration classes were reported from 11 relevant prospective and retrospective studies from 1 SR:²²

• For class III restorations, AFRs ranged from 0% to 3.6% and success rates ranged from 81.5% to 96.4% over 2 to 10 years.

• For class IV restorations, AFRs ranged from 1.46% to 2.1% and success rates ranged from 74.4% to 87.69% over 5 to 14 years.

• For class III and IV restorations, AFRs ranged from 0% to 5% and success rates ranged from 84.8% to 96% over 1 to 4 years.

Bulk-Fill Composites

The authors of 1 UR²³ with 2 relevant SRs with meta-analyses reported a restoration failure rate ranging from 5.57% to 7.1% for bulk-fill composites in permanent posterior teeth at follow-ups ranging from 1 to 6 years (Table 14).

Flowable Composites

One UR²³ with 1 relevant SR with meta-analysis showed a restoration failure rate of 22.6% for flowable composites in NCCLs during 3 years of follow-up in permanent teeth (Table 15).

Ormocer-Based Composites

One UR²³ with 1 relevant SR with meta-analysis showed failure rate of 12.1% for ormocer-based composites in permanent posterior teeth at follow-ups ranging from 1 to 5 years (Table 16).

Glass Ionomer Cement

The authors of 1 relevant SR²⁰ with 1 meta-analysis showed a success rate of 86.9% for restoration of root caries using GIC during 1-year follow-up in permanent teeth (Table 17).

Resin-Modified GICs

The authors of 1 relevant SR²⁰ with 1 meta-analysis reported a success rate of 87.5% for restoration of root caries using RMGIC during 1-year follow-up in permanent teeth (Table 18).

Amalgams

The authors of 1 UR²³ with 2 relevant SRs with meta-analyses and 1 SR¹⁹ with 3 relevant RCTs reported a restoration failure rate of 6%, an AFR of 1.71%, and restoration survival rates ranging from 69.5% to 91.5% using amalgam in permanent posterior teeth at follow-ups ranging from 1 to 10 years. Restoration success rates were not reported in any study (Table 23).

Primary Teeth

Overall, both restoration failure rates and AFRs increased with longer follow-up. However, both outcomes varied widely across follow-up periods. Survival and success rates were not reported for direct restorations of primary teeth.

The authors of 1 UR²⁴ and 1 SR²⁵ evaluated the clinical evidence on the longevity of direct dental restorations in primary teeth. Table 3 summarizes the outcomes regarding the longevity of direct dental restorations in primary teeth based on years of follow-up. The ranges reported in Table 3 combine results across all materials, restoration classes, techniques, and tooth locations reported in the evidence related to primary teeth. Considerable variation in failure rates and AFRs reflects differences in materials, cavity classes, techniques, evaluation criteria, and study populations. The findings related to direct restorations using amalgams were excluded from this table.

Table 3: Summary of Findings for the Longevity of Direct Dental Restorations in Primary Teeth Based on Years of Follow-up

AFR = annual failure rate; NR = not reported; RCT = randomized controlled trial; SR = systematic review; UR = umbrella review.

Findings by Clinical and Restoration Characteristics

Resin Composites

One UR²⁴ with mean estimates from 10 relevant SRs and 1 SR²⁵ with 10 relevant RCTs that evaluated the longevity of direct dental restorations using resin composites reported restoration failure rates ranging from 0 to 27.8% and AFRs ranging from 0 to 18.53% at follow-ups ranging from 1 to 4 years in primary teeth (Table 13).

• The longevity of direct dental restorations using resin composites varied by location in the mouth:

  • Posterior teeth (1 UR²⁴ with a mean estimate from 10 relevant SRs) restoration failure rates reported increased from 14% at 2 years to 20% at 3 years.

  • Molar teeth (1 SR²⁵ with 10 relevant RCTs) restoration failure rates reported ranged from 0% to 27.8%, and AFRs ranged from 0% to 18.53% at follow-ups ranging from 1 to 4 years.

• The longevities of direct dental restorations using resin composites for different restoration classes were reported from 9 relevant RCTs in 1 SR:²⁵

  • For class I, restoration failure rates ranged from 2.63% to 9%, and AFRs ranged from 1.75% to 4.5% over 1.5 to 2 years.

  • For class II, restoration failure rates ranged from 0% to 18%, and AFRs ranged from 0 to 9% over 1 to 3 years.

  • For mixed-class restorations, failure rates ranged from 1.7% to 25%, and AFRs ranged from 1.7% to 6.3% over 1 to 4 years.

Bulk-Fill Composites

One SR²⁵ with 2 relevant RCTs reported a restoration failure rate ranging from 0% to 24.3% and AFRs ranging from 0% to 16.9% using bulk-fill composites at follow-ups ranging from 1 to 1.5 years in molar teeth (Table 14).

Flowable Composites

One SR²⁵ with 1 relevant RCT showed a restoration failure rate of 0% and an AFR of 0% using flowable composites during a 1-year follow-up in primary molar teeth (Table 15).

Glass Ionomer Cement

One UR²⁴ with mean estimates from 13 relevant SRs and 1 SR²⁵ with 5 relevant RCTs that evaluated the longevity of direct dental restorations using GIC reported restoration failure rates ranging 16% to 44% and AFRs ranging from 5.7% to 33% at follow-ups ranging from 1 to 5 years in primary posterior and molar teeth (Table 17).

• The longevity of direct dental restorations using GIC varied based on location in the mouth:

  • Posterior teeth (1 UR²⁴ with a mean estimate from 13 relevant SRs) restoration failure rates ranged from 16% to 21% at 2 years to 16% to 35% at 3 years.

  • Molar teeth (1 SR²⁵ with 5 relevant RCTs) restoration failure rates ranged from 17% to 44% and AFRs ranged from 5.7% to 33% at follow-ups ranging from 1 to 5 years.

• The longevities of direct dental restorations using GIC for different restoration classes were reported from 5 relevant RCTs in 1 SR:²⁵

  • For class I, restoration failure rates ranged from 17% to 33% and AFRs ranged from 5.7% to 33% over 1 to 3 years.

  • For class II, restoration failure rates ranged from 23.9% to 44% and AFRs ranged from 14.7% to 15.9% over 1.5 to 3 years.

  • For mixed-class restorations, failure rates ranged from 26.6% to 32.8% and AFRs ranged from 6.6% to 26.6% over 1 to 5 years.

Resin-Modified GICs

One SR²⁵ with 5 relevant RCTs reported failure rates ranging from 1.9% to 26.1% and AFRs ranging from 1.9% to 16.9% for restorations using RMGIC at follow-ups ranging from 1 to 4 years in primary molar teeth (Table 18).

• The longevities of direct dental restorations using RMGIC for different restoration classes were reported from 5 relevant RCTs in 1 SR:²⁵

  • For class I, the restoration failure rate and AFR were 2% at 1 year.

  • For class II, restoration failure rates ranged from 1.9% to 16.9% and AFRs ranged from 1.9% to 16.9% over 1 to 2 years.

  • For mixed-class restorations, the failure rate was 26.1% and the AFR was 6.5% at 4 years.

High-Viscosity GICs

One SR²⁵ with 8 relevant RCTs reported restoration failure rates ranging from 2.3% to 69.1% and AFRs ranging from 1.2% to 30.2% for restorations using HVGIC at follow-ups ranging from 1 to 4 years in primary molar teeth (Table 19).

• The longevities of direct dental restorations using HVGIC for different restoration classes were reported from 10 relevant RCTs in 1 SR:²⁵

  • For class I, restoration failure rates ranged from 3% to 60.4% and AFRs ranged from 1.2% to 26.8% over 1 to 4 years.

  • For class II, restoration failure rates ranged from 2.9% to 36.1% and AFRs ranged from 2.9% to 25.6% over 1 to 3 years.

  • For mixed-class restorations, failure rates ranged from 9% to 21% and AFRs ranged from 5.8% to 10.5% over 1 to 2 years.

Metal-Reinforced GIC

One SR²⁵ with 1 relevant RCT showed a failure rate of 41.3% and an AFR of 27.5% for restorations using MRGIC for class II restorations at 1.5 years of follow-up in primary molar teeth (Table 20).

Glass Carbomer

One SR²⁵ with 1 relevant RCT showed failure rates and AFRs ranging from 5.8% to 46.2% for restorations using glass carbomer for class II restorations during 1 year of follow-up in primary molar teeth (Table 21).

Compomer

One UR²⁴ with mean estimates from 6 relevant SRs and 1 SR²⁵ with 8 relevant RCTs that evaluated the longevity of direct dental restorations using compomer reported restoration failure rates ranging from 0% to 44% and AFRs ranging from 0% to 14.7% at follow-ups ranging from 1 to 4 years in primary posterior and molar teeth (Table 22).

• The longevity of direct dental restorations using compomer varied based on location in the mouth:

  • One UR²⁴ with mean estimates from 6 relevant SRs reported the restoration failure rate decreased from 19% at 2 years to 13% at 3 years in primary posterior teeth. AFRs were not reported for posterior teeth.

  • One SR²⁵ with 8 relevant RCTs reported restoration failure rates ranging from 0% to 44% and AFRs ranging from 0% to 14.7% at follow-ups ranging from 1 to 4 years in primary molar teeth.

• The longevities of direct dental restorations using compomer for different restoration classes were reported from 8 relevant RCTs in 1 SR:²⁵

  • For class II, restoration failure rates ranged from 0% to 44% and AFRs ranged from 0% to 14.7% over 1 to 3 years.

  • For mixed-class restorations, failure rates ranged from 1.7% to 43.8% and AFRs ranged from 1.7% to 14.6% over 1 to 4 years.

Amalgams

One UR²⁴ with mean estimates from 9 relevant SRs and 1 SR²⁵ with 4 relevant RCTs that evaluated the longevity of direct dental restorations using amalgams reported restoration failure rates ranging from 2% to 36% and AFRs ranging from 1% to 28% at follow-ups ranging from 1 to 5 years in primary posterior and molar teeth (Table 23).

• The longevity of direct dental restorations using amalgams varied based on location in the mouth:

  • One UR²⁴ with mean estimates from 9 relevant SRs reported the failure rate increased from 11% at 2 years to 21% at 3 years in primary posterior teeth. AFRs were not reported for posterior teeth.

  • One SR²⁵ with 4 relevant RCTs reported restoration failure rates ranging from 2% to 32% and AFRs ranging from 1% to 28% at follow-ups ranging from 1 to 5 years in primary molar teeth.

• The longevities of direct dental restorations using amalgam for different restoration classes were reported from 4 relevant RCTs in 1 SR:²⁵

  • For class II, restoration failure rates ranged from 2% to 32% and AFRs ranged from 1% to 28% over 1 to 2 years.

  • For mixed-class restorations, the failure rate was reported as 20.2% and the AFR was 4% at 5 years.

Summary of Relevant Factors Affecting Restoration Failure and Longevity

The longevity of dental restorations is influenced by many factors, including whether teeth are permanent or primary; patient caries risk; tooth location and remaining tooth structure; cavity size and complexity; occlusal and mechanical loading; restorative material; adhesive protocol; and clinical technique.

Permanent Teeth

Evidence on relevant factors associated with failure and longevity of direct restorations in permanent teeth was available from 4 SRs^19-22 (Table 24). Evidence from these 4 SRs^19-22 indicated that restoration longevity is multifactorial, with important contributions from patient caries risk; tooth location and remaining tooth structure; cavity size and complexity; occlusal and 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.^19-22 However, the evidence remains heterogeneous, particularly for complex posterior restorations.

Restoration failure varied by tooth location and restoration type, with biological, mechanical, and aesthetic causes contributing to re-intervention.^19,21 In posterior restorations, the most frequently reported reasons for restoration failure were secondary caries and fracture of the restoration or tooth, with endodontic treatment also reported as a reason for failure over longer follow-up periods.^19,21 For root caries restorations, failure was mainly related to restoration loss, dislodgement or loss of retention, marginal defects, and secondary caries.²⁰ In anterior restorations, restoration fracture, chipping, colour mismatch, and marginal discoloration were common reasons for failure.^21,22 Younger age, larger restorations, adhesive technique, and composite type were also identified as potential factors associated with failure.^21,22 Across anterior and posterior restorations, additional reasons for re-intervention included marginal breakdown, surface deterioration, aesthetic compromise, and endodontic treatment.²¹

Overall, the evidence suggests some variation in failure patterns by restoration location. Posterior restorations were predominantly affected by caries and mechanical failures,^19,21 whereas anterior restorations more commonly involved fracture and aesthetic deterioration.^21,22 Cervical or root restorations were particularly affected by loss of retention and marginal defects.^20,21 These findings were observed over follow-up periods ranging from approximately 6 months to 30 years, although the contributing evidence and duration of follow-up varied considerably across outcomes.

Primary Teeth

Evidence on relevant factors associated with failure and longevity of direct restorations in permanent teeth was available from 1 UR²⁴ and 1 SR²⁵ (Table 25). Evidence from these reviews indicates that restoration longevity in primary teeth is influenced by characteristics of the cavity, tooth, restorative material, and operative technique.^24,25

The main reported causes of restoration failure in primary teeth were secondary caries, restoration loss, and marginal ridge chipping or fracture with loss of proximal contact.^24,25 Thus, both biological factors, particularly recurrent caries, and mechanical deterioration contribute to restoration failure. The reviews also identified tooth type, child age, caries lesion depth, affected tooth surfaces, and extent of caries removal as factors that may influence treatment outcomes, although the evidence for individual factors was not consistently established across studies.^24,25

Moisture control and operative technique may also affect longevity. In particular, rubber dam isolation was associated with higher success than cotton roll isolation in the evidence summarized by 1 UR (93.6% versus 77.5%, respectively).²⁴ Operator experience was also identified as a potentially relevant factor.²⁵ However, there was substantial heterogeneity among studies with respect to restorative materials, cavity characteristics, isolation methods, techniques, follow-up, and outcome assessment, limiting conclusions about the independent effect of individual factors.²⁵ It was also reported that single-surface restorations generally have better outcomes than multisurface restorations, with reported failure rates of approximately 4.8% to 7.6% for single-surface restorations compared with 9.5% to 14.7% for multisurface restorations.²⁴ Larger and more extensive restorations may therefore have a greater risk of failure because of increased mechanical and functional demands.²⁴

Overall, for primary teeth, the evidence suggests that restoration size or number of surfaces, caries risk and secondary caries, tooth characteristics, moisture control, and operative technique are important considerations when assessing restoration longevity.^24,25 However, the evidence does not establish a consistent independent effect for all potential prognostic factors.

Limitations

Heterogeneity and Quality of Evidence

The body of evidence was highly heterogeneous with respect to tooth location, restorative materials, cavity characteristics, clinical techniques, follow-up duration, and definitions of restoration failure.^12,19-25 Differences in outcome definitions were particularly relevant; some studies considered a repaired restoration to have survived, whereas others classified repair as a failure. Consequently, survival may overestimate the time to first re-intervention compared with success, which is particularly important when the outcome of interest is the need for repair or replacement.²¹ One UR²³ identified heterogeneity in eligibility criteria, evaluation methods, and outcome definitions across its included SRs. There was also some overlap in the underlying evidence from SRs included in both URs.^23,24 One UR²⁴ reported moderate overlap among primary studies, and the other UR²³ identified redundancy across included SRs. Thus, the included evidence^12,19-25 should not be considered 8 completely independent bodies of evidence, and findings reported consistently across reviews may partly reflect repeated inclusion of the same primary studies.

The methodological quality and certainty of the available evidence were variable, reducing confidence in some findings.¹² Several of the reviews had important methodological limitations, and many underlying primary studies had an unclear or high risk of bias.^12,24 Patient characteristics such as age, sex, cause of tooth wear, caries risk, and bruxism were not reported in many studies, and the selection of cases with lower risk of restoration failure may have biased estimates of restoration performance.^12,19-22,25

Evidence Gaps

Evidence quantity varied considerably by restoration type and material. Relatively extensive long-term evidence was available for conventional resin composite restorations, whereas evidence for newer materials and techniques was substantially more limited. For example, long-term performance of bulk-fill restorations and ormocer-based composites beyond 5 years remains underreported.²¹ In addition, evidence on the longer-term longevity of direct restorations in primary teeth was limited, with no data beyond 5 years and lack of evidence on restoration survival or success outcomes. These gaps limit conclusions about their longer-term longevity and time to re-intervention.

There were also important gaps for specific clinical populations and indications. For root caries, 9 studies with small numbers of participants were included, and most provided follow-up of approximately 12 months; very few contributed evidence at 24 months or longer.²⁰ As a result, no factor could be clearly associated with long-term root caries restoration success.²⁰ Similarly, evidence directly comparing complex posterior restorations was limited.¹⁹ Important characteristics such as remaining tooth walls, cusp coverage, subgingival margins, isolation technique, and patient risk factors were frequently missing.¹⁹ Evidence was also limited for monitoring versus restorative treatment for moderate tooth wear, and studies did not adequately evaluate whether delaying restoration affects subsequent tooth survival, treatment burden, costs, or quality of life.¹²

Generalizability to the Context of Canada

While only 1 primary study was conducted in Canada, the findings are likely generalizable to dental practice in Canada, particularly in well-resourced settings using materials and techniques similar to those evaluated in the studies.^21,23 Generalizability is further limited by differences in outcome definitions and clinical settings. Restoration survival, success, repair, and replacement were not consistently defined, which is particularly important when the outcome of interest is time to re-intervention.

Applicability is limited by inconsistent reporting of patient characteristics such as caries risk, socioeconomic status, bruxism, comorbidities, medication use, and salivary dysfunction.^21,23 Moreover, many studies were conducted in university or controlled clinical environments and may not fully reflect routine care in community, public, rural, or remote settings in Canada. Therefore, applicability is more uncertain for patients at increased risk for dental caries, equity-deserving populations, and newer restorative approaches with limited long-term evidence.^21,23

Equity Considerations

Evidence related to equity was limited. Although socioeconomic status has been identified as a potential determinant of restoration longevity, no reviews reported outcomes stratified by socioeconomic or other equity-related characteristics.²¹ The included reviews did not provide separate estimates for equity-deserving populations, such as people living in rural or remote communities, people with limited access to dental care, or other populations experiencing barriers to oral health services. Therefore, it is uncertain whether the reported restoration longevity estimates apply equally across these populations.

Access to resources may also modify restoration outcomes. Moisture control, availability of particular materials, ability to attend follow-up visits, and access to preventive or restorative care may differ across settings. For example, the evidence on root caries restorations suggested that less resource-intensive approaches, such as atraumatic restorative treatment, may be relevant in outreach settings; however, some patients, such as older adults who depend on others for care and may have difficulty tolerating dental procedures, may require different material choices when moisture control is difficult.²⁰ One UR²³ similarly identified a need for research in equity-deserving populations, underrepresented regions, and public health systems.

No evidence on patient engagement was reported in the 8 reports.^12,19-25 Future studies would benefit from examining whether outcomes considered important to patients, such as time to re-intervention, treatment burden, discomfort, aesthetics, costs, and oral health–related quality of life, differ across populations and care settings.

Conclusions and Implications for Decision- or Policy-Making

This rapid overview of reviews evaluated the literature on the clinical evidence regarding the longevity of direct dental restorations as well as the most relevant factors affecting restorative longevity. We identified 8 publications^12,19-25 that met our inclusion criteria and addressed the research question.

The evidence summarized in this report is drawn from 6 SRs^12,20-22,25 and 2 URs^23,24 with some overlap in primary studies, meaning that data from the same participants were included in more than 1 SR or UR (refer to Appendix 6 for a citation matrix illustrating the degree of primary study overlap). As a result, some evidence may be disproportionately represented in the overall conclusions.

Summary of Evidence

No definitive or consistent conclusion regarding longevity of direct dental restorations can be drawn from the identified evidence. Across both permanent and primary teeth, restoration failure generally became more frequent with longer follow-up; however, substantial heterogeneity limited comparisons across follow-up periods and precluded establishing a standard replacement or re-intervention interval. Longevity outcomes varied substantially by restorative material, restoration class and locations, clinical technique, outcome definition, and follow-up duration. Consequently, the findings did not establish which materials, locations, or cavity type or class were associated with the longest or shortest longevity. In addition, the available evidence did not support a single expected replacement or re-intervention interval applicable to all direct dental restorations. Common causes of restoration failure included secondary caries, restoration or tooth fracture, loss of retention, marginal deterioration, and discoloration. For permanent teeth, evidence indicated that the longevity of direct dental restorations is influenced by multiple patient-, tooth-, restoration-, material-, and technique-related factors.^19-22 Failure patterns varied by location in the mouth; posterior restorations were mainly affected by secondary caries and fracture of the restoration or tooth; anterior restorations by fracture and aesthetic deterioration; and cervical or root restorations by loss of retention and marginal defects. For primary teeth, the longevity of direct dental restorations was influenced by cavity and tooth characteristics, restorative material, moisture control, and operative technique. The main causes of failure were secondary caries, restoration loss, and marginal ridge chipping or fracture. However, substantial heterogeneity limited conclusions about the independent effects of individual factors.

Taken together, the available evidence provides a useful indication of the longevity and common failure patterns of direct dental restorations, but precise estimates should be interpreted cautiously. Heterogeneous definitions of failure, differences in follow-up, repeated inclusion of some primary studies, variable methodological quality, sparse evidence for newer materials and specific indications, and limited reporting of patient- and equity-related characteristics restrict both the validity and generalizability of the findings. There is a need for more recent, long-term, practice-based studies using standardized definitions of survival, success, repair, replacement, and time to first re-intervention with adequate representation of diverse patient groups and care settings in Canada.²¹

Summary of Related Recommendations for Direct Dental Restorations

This review did not identify recommendations on routine replacement of a direct dental restoration after a specified number of years. Across guidance documents, restoration age alone was not considered an indication for replacement. The available guidance generally supports a condition-based approach to re-intervention, with no universal replacement interval.^5,28 Decisions were based on clinical and radiographic findings, symptoms, tooth prognosis, caries risk, restoration size and locations, and patient preferences.^5,28 For example, the 2023 American Dental Association guideline considered restoration longevity and failure important outcomes but found that many material comparisons did not report time to repair or replacement. It therefore provides no expected longevity or replacement interval.²⁹ Similarly, the 2024 German S3 guideline does not recommend scheduled replacement. It reported acceptable longevity for direct composite restorations, including observations of up to 15 years for anterior tooth-shape corrections and 13 years for class V restorations, although evidence certainty varied.^30,31 These follow-up periods describe observed performance and are not recommended replacement times.

The revised FDI World Dental Federation criteria use the restoration’s current condition — not its age — to guide treatment.²⁸ Acceptable restorations may be retained or corrected through minor measures, clinically unsatisfactory restorations generally require repair, and clinically poor restorations may require replacement.²⁸ The FDI World Dental Federation policy recommends considering monitoring, refurbishment, sealing, or repair before complete replacement.⁵

Administrative dental benefit schedules take a different approach. These frequency limits, supported by most dental benefit plans, are reimbursement controls — not clinical standards, warranties, expected service lives, or recommendations to replace restorations at the end of the interval. A restoration that fails within a certain time period (e.g., 24 or 36 months) may still require clinically necessary treatment, while a serviceable restoration may remain in place well beyond this time period.

Considerations for Decision- or Policy-Making

This rapid overview of reviews summarizes the current clinical evidence on longevity of direct dental restorations. No definitive or consistent conclusion regarding longevity of direct dental restorations can be drawn from the identified evidence. Current evidence suggests that longevity of direct dental restorations is influenced by factors beyond material choice, including caries risk, restoration size and locations, mechanical loading, moisture control, adhesive technique, and operator-related factors.

Evidence is limited and less certain for newer materials, such as ion-releasing bioactive materials. A recent SR³² of 10 RCTs with follow-up periods of 1 to 8 years investigated the efficacy of bioactive composites compared to conventional resin composites based on the longevity of direct restorations. The meta-analysis indicated that bioactive resin materials — including ACTIVA BioACTIVE, giomers, and Cention N — did not differ significantly from conventional resin composites in preventing secondary caries or reducing retention loss, regardless of follow-up duration. The authors concluded that bioactive materials offer no additional benefit for improving the longevity of direct posterior restorations.³²

Evidence was limited for populations who may experience barriers to dental care, including people living in rural or remote areas, people with lower socioeconomic status, older adults, and other equity-deserving groups. Socioeconomic status and access-related factors may influence restoration longevity, but they were inconsistently evaluated.²¹ It is also important to consider whether differences in access to preventive care, follow-up, moisture control equipment, restorative materials, or clinician expertise could affect outcomes across populations and settings. These considerations may help contextualize decision-making in Canada.

There is no single expected lifespan that applies to all direct dental restorations. Because survival, success, repair, and replacement were defined inconsistently, estimates of longevity may not fully capture when patients first require additional treatment.²¹ Although cumulative failure generally increased with longer follow-up, longevity outcomes varied substantially by material, restoration class and locations, cavity complexity, patient caries risk, and clinical technique. More long-term studies using standardized definitions of failure, survival, success, and time to first re-intervention are needed.

References

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17.Birch S, Price R, Andreou P, Jones G, Portolesi A. Variations in survival time for amalgam and resin composite restorations: a population based cohort analysis. Community Dent Health. 2016;33(3):208-212. doi:10.1922/CDH_3825Birch05 PubMed

18.Shea BJ, Reeves BC, Wells G, et al. AMSTAR 2: a critical appraisal tool for systematic reviews that include randomised or non-randomised studies of healthcare interventions, or both. BMJ. 2017;358:j4008. doi:10.1136/bmj.j4008 PubMed

19.Santos M, Saadaldin S, Rego H, Tayan N, Melo NM, El-Najar M. Clinical Longevity of Complex Direct Posterior Resin Composite and Amalgam Restorations: A Systematic Review and Meta-analysis. Oper Dent. 2025;50(4):E30-E46. doi:10.2341/24-007-lit PubMed

20.Wen Y, Zhao X, Li SKY, Lo ECM, Jiang CM. Factors associated with the success of restorative treatment for root caries: A systematic review with meta-analysis. J Dent. 2025;153:105539. doi:10.1016/j.jdent.2024.105539 PubMed

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23.Fernández E, Gil AC, Caviedes R, Diaz L, Bersezio C. Clinical Longevity of Direct Dental Restorations: An Umbrella Review of Systematic Reviews. J Esthet Restor Dent. 2026;38(2):307-324. doi:10.1111/jerd.70052 PubMed

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28.Hickel R, Mesinger S, Opdam N, et al. Correction to: Revised FDI criteria for evaluating direct and indirect dental restorations-recommendations for its clinical use, interpretation, and reporting. Clin Oral Investig. 2023;27(6):2593. doi:10.1007/s00784-022-04851-w PubMed

29.Dhar V, Pilcher L, Fontana M, et al. Evidence-based clinical practice guideline on restorative treatments for caries lesions: A report from the American Dental Association. J Am Dent Assoc. 2023;154(7):551-566.e51. doi:10.1016/j.adaj.2023.04.011 PubMed

30.Wolff D, Frese C, Frankenberger R, et al. Direct Composite Restorations on Permanent Teeth in the Anterior and Posterior Region - An Evidence-Based Clinical Practice Guideline - Part 1: Indications for Composite Restorations. J Adhes Dent. 2024;26:185-200. doi:10.3290/j.jad.b5748881 PubMed

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Appendix 1: Detailed Methods and Selection of Included Studies

Please note that this appendix has not been copy-edited.

What Is a Rapid Review?

Rapid Reviews are based on accelerated and abbreviated SR methods, balancing timeliness with rigour, to allow for timely decision-making. Due to these abbreviated methods, Rapid Reviews have some limitations. For example, unlike in SRs, for which at least 2 independent reviewers are needed to screen studies to reduce selection bias, a single reviewer was required to include, extract the data, and appraise a study. In consultation with the external requester, we conducted a rapid overview of reviews; we set our search time frame from January 2021 onward and included and appraised SRs and URs (overview of SRs) published over the past 5 years. The included SRs and URs published in this time frame also include older studies. Our rapid overview of reviews intends to summarize the available evidence, rather than provide recommendations. These findings should not be interpreted as prescriptive guidance.

Literature Search Methods

An information specialist conducted a literature search on key resources including MEDLINE, the Cochrane Database of Systematic Reviews, the International HTA Database, the websites of health technology assessment agencies in Canada and major international HTA agencies, as well as a focused internet search. The search approach was customized to retrieve a limited set of results, balancing comprehensiveness with relevance. The search strategy comprised both controlled vocabulary, such as the US National Library of Medicine’s MeSH (Medical Subject Headings), and keywords. Search concepts were developed based on the elements of the research questions and selection criteria. The main search concepts were direct dental restorations and longevity. Search filters were applied to limit retrieval to health technology assessments, systematic reviews, meta-analyses, indirect treatment comparisons. An additional search was conducted using the search concept direct dental restorations; search filters were applied to this search to limit retrieval to guidelines. The searches were completed on July 17, 2026, and were limited to English-language documents published since January 1, 2021. The search strategies are available on request.

Selection Criteria and Methods

One reviewer screened citations and selected studies. In the first level of screening, titles and abstracts were reviewed and potentially relevant articles were retrieved and assessed for inclusion. The final selection of full-text articles was based on the inclusion criteria presented in Table 1.

Exclusion Criteria

Articles were excluded if they:

• did not meet the selection criteria outlined in Table 1

• were duplicate publications or were published before January 2021

• were SRs in which all relevant studies were captured in other more recent or more comprehensive SRs

• were SRs captured in an included UR

• were published in languages other than English (for feasibility reasons).

Critical Appraisal of Individual Studies

The included publications were critically appraised by 1 reviewer using the following tool as a guide: A MeaSurement Tool to Assess systematic Reviews 2 (AMSTAR 2)¹⁸ for SRs. Summary scores were not calculated for the included studies; rather, the strengths and limitations of each included publication were described narratively.

Data Extraction

One reviewer extracted data directly into standardized tables created in Microsoft Word, which were modified as necessary. The extracted information included study characteristics, methodology (e.g., study design), population, intervention, and results regarding the outcomes of interest.

One reviewer extracted information from the included studies using the PROGRESS- Plus²⁷ tool to describe different population groups. Each included study was checked to determine if PROGRESS- Plus²⁷ criteria were reported by study authors to describe the participants; detailed characteristics, if available, were then extracted and reported in Appendix 3, Table 4. The main PROGRESS-Plus²⁷ characteristics include place of residence; race, ethnicity, culture, and/or language; occupation; gender and/or sex; religion; education; socioeconomic status; and social capital. As part of report writing, we discuss these characteristics across the evidence, where available, when presenting results within the text.

When reporting on sex, gender, race, or ethnicity in this rapid overview of reviews, we planned to retain the language used by the original study authors, and, whenever possible, we referred to these groups based on guidance from Canada’s Drug Agency Style: A Guide for Authors and Editors³³ at the time this rapid overview of reviews was conducted, with an understanding that language is constantly evolving.

Appendix 2: Selection of Included Studies

Please note that this appendix has not been copy-edited.

Figure 1: Selection of Included Studies — PRISMA²⁶ Flow Chart of Selected Reports

PRISMA = Preferred Reporting Items for Systematic Reviews and Meta-Analyses; SR = systematic review; UR = umbrella review.

Appendix 3: Characteristics of Included Publications

Please note that this appendix has not been copy-edited.

Table 4: Characteristics of Included Systematic Reviews and Umbrella Reviews

AFR = Annual failure rates; ART = atraumatic restorative treatment; GIC = glass ionomer cements; HVGIC = high-viscosity glass ionomer cements; MRGIC = metal-reinforced glass ionomer cement; NR = not reported; nRCTs = nonrandomized controlled trial; RCT = randomized controlled trial; RMGIC = resin- modified glass ionomer cements; SR = systematic review; UR = umbrella review.

^aThe main PROGRESS-Plus characteristics include place of residence, race, ethnicity, culture, language, occupation, gender, sex, religion, education, socioeconomic status, and social capital, personal characteristics associated with discrimination (e.g., age, disability), features of relationships, and time-dependent relationships.²⁷

^bMinor AFR: AFR for restorations requiring repair, refurbishment, polishing, or adjustment without complete replacement.

^cMajor AFR: AFR for restorations requiring complete replacement of the restoration.

^dMany of the included primary studies in this SR did not report the gender of participants or reported conflicting information.

Appendix 4: Critical Appraisal of Included Publications

Please note that this appendix has not been copy-edited.

Table 5: Strengths and Limitations of the Fernández et al. (2026) Study²³ Using AMSTAR 2¹⁸

AMSTAR 2 = A MeaSurement Tool to Assess systematic Reviews 2; GRADE = Grading of Recommendations Assessment, Development and Evaluation; NA = not applicable; SR = systematic review; UR = umbrella review.

Table 6: Strengths and Limitations of the Alani et al. (2025) Study¹² Using AMSTAR 2¹⁸

AMSTAR 2 = A MeaSurement Tool to Assess systematic Reviews 2; NA = not applicable; n-RCT = nonrandomized controlled trial; RCT = randomized controlled trial; RoB = risk of bias; ROBINS-I = Risk Of Bias In Nonrandomized Studies of Interventions; SR = systematic review.

Table 7: Strengths and Limitations of the Santos et al. (2025) Study¹⁹ Using AMSTAR 2¹⁸

AMSTAR 2 = A MeaSurement Tool to Assess systematic Reviews 2; NA = not applicable; RCT = randomized controlled trial; RoB = Risk of Bias; SR = systematic review.

Table 8: Strengths and Limitations of the Wen et al. (2025) Study²⁰ Using AMSTAR 2¹⁸

AMSTAR 2 = A MeaSurement Tool to Assess systematic Reviews 2; NA = not applicable; NRSI = nonrandomized study of intervention; RCT = randomized controlled trial; RoB = Risk of Bias; SR = systematic review.

Table 9: Strengths and Limitations of the Demarco et al. (2023) Study²¹ Using AMSTAR 2¹⁸

AMSTAR 2 = A MeaSurement Tool to Assess systematic Reviews 2; NA = not applicable; RoB = Risk of Bias; SR = systematic review.

Table 10: Strengths and Limitations of the Amend et al. (2022) Study²⁴ Using AMSTAR 2¹⁸

AMSTAR 2 = A MeaSurement Tool to Assess systematic Reviews 2; NA = not applicable; RoB = risk of bias; ROBIS = Risk of Bias in Systematic Reviews; SR = systematic review; UR = umbrella review.

Table 11: Strengths and Limitations of the Amend et al. (2022) Study²⁵ Using AMSTAR 2¹⁸

AMSTAR 2 = A MeaSurement Tool to Assess systematic Reviews; NA = not applicable; RCT = randomized controlled trial; RoB = Risk of Bias.

Table 12: Strengths and Limitations of the Shah et al. (2021)²² Study Using AMSTAR 2¹⁸

AMSTAR 2 = A MeaSurement Tool to Assess systematic Reviews 2; NA = not applicable; RoB = Risk of Bias; SR = systematic review.

Appendix 5: Main Study Findings

Please note that this appendix has not been copy-edited.

Table 13: Summary of Findings by Materials Evaluated — Resin Composites

AFR = annual failure rate; ART = atraumatic restorative treatment; CI = confidence interval; ER: estimated rate; ESR = estimated success rate; FDI = World Dental Federation; NCCLs = noncarious cervical lesions; NR = not reported; nRCT = nonrandomized controlled trial; PUFA = pulp, ulceration, fistula, abscess; RCT = randomized controlled trial; SR = systematic review; USPHS = US Public Health Service.

^aFor consistency, the authors of this review converted the number of months to number of years.

^bF1-F3 restoration failure classification (F1 = replacement; F2 = repair; F3 = refurbishment/polishing), used to derive major failure, minor failure, survival, and success outcomes.

^cMinor AFR: AFR for restorations requiring repair, refurbishment, polishing, or adjustment without complete replacement.

^dMajor AFR: AFR for restorations requiring complete replacement of the restoration.

^eThe meta-analysis figure of this SR reported failure rate as proportion (i.e., 0.43; 95% CI, 24 to 63). For consistency, the authors of this review converted the proportions to percentages.

^fReported from Shah et al. (2021).²²

Table 14: Summary of Findings by Materials Evaluated — Bulk-Fill Composites

CI = confidence interval; FDI = World Dental Federation; NR = not reported; RCT = randomized controlled trial; SR = systematic review, USPHS = US Public Health Service.

^aFor consistency, the authors of this review converted the number of months to number of years.

Table 15: Summary of Findings by Materials Evaluated — Flowable Composites

CI = confidence interval; NR = not reported; RCT = randomized controlled trial; SR = systematic review.

Table 16: Summary of Findings by Materials Evaluated — Ormocer-Based Composites

CI = confidence interval; NR = not reported; RCT = randomized controlled trial; SR = systematic review.

^aFor consistency, the authors of this review converted the number of months to number of years.

Table 17: Summary of Findings by Materials Evaluated — GIC

ART = atraumatic restorative treatment; CI = confidence interval; DPDHS = Danish Public Dental Health Service; ESR = estimated success rate; FDI = World Dental Federation; GIC = glass ionomer cement; NR = not reported; PUFA= pulp, ulceration, fistula, abscess; RCT = randomized controlled trial; SR = systematic review; USPHS = US Public Health Service.

^aFor consistency, the authors of this review converted the number of months to number of years.

Table 18: Summary of Findings by Materials Evaluated — RMGIC

CI = confidence interval; ESR = estimated success rate; NR = not reported; RCT = randomized controlled trial; RMGIC = resin-modified glass ionomer cement; SR = systematic review.

^aFor consistency, the authors of this review converted the number of months to number of years.

Table 19: Summary of Findings by Materials Evaluated — HVGIC

ART = atraumatic restorative treatment; HVGIC = high-viscosity glass ionomer cement; NR = not reported; USPHS = US Public Health Service.

Table 20: Summary of Findings by Materials Evaluated — MRGIC

MRGIC = metal-reinforced glass ionomer cement; NR = not reported; USPHS = US Public Health Service.

Table 21: Summary of Findings by Materials Evaluated — Glass Carbomer

GC = glass carbomer; NR = not reported.

Table 22: Summary of Findings by Materials Evaluated — Compomer

ART = atraumatic restorative treatment; CI = confidence interval; DPDHS = Danish Public Dental Health Service; FDI = World Dental Federation; NR = not reported; PUFA = pulp, ulceration, fistula, abscess; RCT = randomized controlled trial; SR = systematic review; USPHS = US Public Health Service.

^aFor consistency, the authors of this review converted the number of months to number of years.

Table 23: Summary of Findings by Materials Evaluated — Amalgam