The clinical diagnosis of recurrent caries is the most common reason for replacement of all types of restorations in general dental practice. Marked variations in the diagnosis of the lesions have been reported. The prevention of recurrent lesions by the use of fluoride-releasing restorative materials has not been successful.
Types of Studies Reviewed
The author focused on practice-based studies in the literature. These studies are not scientifically rigorous, but they reflect “real-life” dental practice. Few experimental studies on recurrent carious lesions in vivo have been reported, but bacteriological studies indicate that the etiology is similar to that of primary caries.
Results
Recurrent carious lesions are most often located on the gingival margins of Class II through V restorations. Recurrent caries is rarely diagnosed on Class I restorations. The diagnosis is difficult, and it is important to differentiate recurrent carious lesions from stained margins on resin-based composite restorations. Overhangs, even minute in size, are predisposed to plaque accumulation and the development of recurrent caries. The development of recurrent lesions is unrelated to microleakage.
Clinical Implications
As recurrent carious lesions are localized and limited, alternative treatments to restoration replacement are suggested. Polishing may be sufficient. If not, exploratory preparations into the restorative material adjacent to the localized defect can reveal the extent of the lesion. Such explorations invariably show that the lesion does not progress along the tooth-restoration interface. The defect, therefore, may be repaired in lieu of being completely replaced. Repair and refurbishing of restorations save tooth structure. These simple procedures also increase the life span of the restoration.
Section snippets
FREQUENCY OF DIAGNOSED RECURRENT CARIES
Ever since the G.V. Black period, the clinical diagnosis of recurrent caries has been shown in studies from many countries, including the United States, to be the most common reason by far for replacement of all types of restorations in permanent and primary teeth.2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 The percentage of restorations in adults that were replaced because of the clinical diagnosis of recurrent caries was consistently about 50 percent, with a
LOCATION OF CLINICALLY DIAGNOSED RECURRENT CARIES
Studies have been conducted in which general practitioners were asked to indicate where recurrent carious lesions were located on diagrams of teeth, with outlines of the extent of the restorations examined.28, 29, 30 These studies have shown that recurrent caries was seen predominantly on the gingival margins of all types of Class II through Class V restorations, while it was rarely associated with Class I restorations or on the occlusal part of Class II restorations. Recurrent caries was seen
BACTERIOLOGY OF RECURRENT CARIES
Little attention has been paid to the microbiology of recurrent caries. Kidd and colleagues33 performed cultures on samples of dentin taken from the dentinoenamel junction at intervals during cavity preparation using a rubber dam. They found no significant differences in the microflora in samples from cavity walls involving primary and recurrent caries.
The amount of plaque and its cariogenicity at restoration margins depends on the restorative material.34, 35, 36, 37, 38 These findings indicate
DIAGNOSIS OF RECURRENT CARIES
Recurrent caries at proximal or gingival locations in restorations can be diagnosed by radiography provided the X-rays are at an optimal angle in relation to the lesion. Because restorative materials are radiopaque, they may hide the lesion completely or partially (Figure 3, Figure 4). The burnout that frequently occurs at the cervical margin also may make interpretation difficult. In general, the diagnosis of recurrent caries lacks consistency,52, 53, 54, 55, 56 and the diagnostic variations
THE TREATMENT OF RECURRENT CARIES
The clinical diagnosis of recurrent caries invariably has resulted in the replacement of the restoration affected. But this clinical approach to the problem has been challenged.59 If clinically diagnosed recurrent caries often is a marginal defect rather than a carious lesion, it is unlikely that fluoride or other materials releasing known caries-preventing agents will reduce the frequency with which recurrent caries is diagnosed. In fact, practice-based cross-sectional studies of reasons for
CONCLUSIONS
Uncertainty exists with regard to the clinical diagnosis of recurrent caries. A review of the literature demonstrates marked deviations in this diagnosis among clinicians. Surveys have shown great variations in or lack of defined criteria to characterize these lesions. Teeth with stained margins of tooth-colored restorations and ditched margins in which the explorer tends to stick often are misdiagnosed as having recurrent caries. It appears that only frankly cavitated carious lesions adjacent
2024, Journal of the Mechanical Behavior of Biomedical Materials
The existing knowledge is insufficient for comprehending the fatigue survival and fracture resistance of molars that have deep approximal direct and indirect restorations, whether with or without deep margin elevation (DME).
The aim of this laboratory and in silico study is to investigate the fatigue survival, fracture strength, failure pattern and tooth deformation of molars restored with DME in combination with a direct or indirect restoration.
This study utilized 45 extracted sound human molars, divided into three groups (n = 15). Standardized 100% inter-cuspal inlay preparations were performed, extending 2 mm below the CEJ and immediate dentin sealing (IDS) was applied. Group 1 (Co_1) was restored with direct composite; Group 2 (Hyb_2) with a 2 mm DME of direct composite and a glass-ceramic lithium disilicate restoration; Group 3 (Cer_3) a glass-ceramic lithium disilicate restoration. All specimens were exposed to a fatigue process involving thermal-cyclic loading (50N for 1.2 × 106 cycles at 1.7 Hz, between 5 and 55 °C), if teeth survived, they were fractured using a load-to-failure test and failure types were analyzed. Finite element analysis (FEA) was conducted to assess tooth deformation and tensile stress in the restorations. Statistical evaluation of fracture strength was conducted using the Kruskal-Wallis test. Fisher's exact test was utilized to analyze the fracture types and repairability. A statistical significance level of α < 0.05 was set for all analyses.
All specimens successfully withstood the fatigue testing procedure, and no statistically significant differences in fracture strength were observed among the three groups (P > 0.05). The Fisher's exact test indicated a significant association between the restorative material and fracture type (F2 = 18.315, df = 2, P = 0.004), but also for repairability (F2 = 13.725, df = 2, P = 0.001). Crown-root fractures were significantly more common in the Cer_3 group compared to the Co_1 group (P = 0.001) and the Co_1 group had significantly more repairable fractures (F2 = 13.197, df = 2, P = 0.001). FEA revealed comparable outcomes of deformation among models and higher maximum tensile stress on models with higher frequency of catastrophic failures.
All tested restoration materials exhibited comparable fatigue survival and fracture strength in this laboratory and in silico study. However, it is important to recognize the potential for more severe and irreparable fractures when opting for deeply luted glass-ceramic inlay restorations in clinical practice. In such cases, it would be prudent to consider the alternative option being a direct composite approach, because of its more forgiving fracture types and repairability.
Molars with deep approximal direct and indirect restorations, whether with or without DME, are comparable in their fatigue survival and fracture resistance to withstand intra-oral forces. Deep direct restorations exhibit more repairable fractures compared to deeply luted glass-ceramics.
The objective is to compare the preventive effect on secondary caries of glass ionomer cement (GIC) restorations with amalgam or resin-composite restorations.
Two independent researchers conducted a systematic search of English publications in PubMed, Web of Science, Cochrane and Scopus. They selected randomized clinical trials comparing secondary caries incidences around GIC restorations (conventional GIC or resin-modified GIC) with amalgam or resin-composite restorations. Meta-analysis of the secondary-caries incidences with risk ratio (RR) and 95% confidence interval (95% CI) as the effect measure was performed.
This review included 64 studies. These studies included 8310 GIC restorations and 5857 amalgam or resin-composite restorations with a follow-up period from 1 to 10 years. Twenty-one studies with 4807 restorations on primary teeth and thirty-eight studies with 4885 restorations on permanent teeth were eligible for meta-analysis. The GIC restorations had a lower secondary caries incidence compared with amalgam restorations in both primary dentition [RR= 0.55, 95% CI:0.41–0.72] and permanent dentition [RR= 0.20, 95% CI:0.11–0.38]. GIC restorations showed similar secondary caries incidence compared with resin-composite restorations in primary dentition [RR= 0.92, 95% CI:0.77–1.10] and permanent dentition [RR= 0.77, 95% CI:0.39–1.51]. Conventional GIC restorations showed similar secondary caries incidence compared with resin-modified GIC-restored teeth in both primary dentition [RR= 1.12, 95% CI:0.67–1.87] and permanent dentition [RR= 1.63, 95% CI:0.34–7.84].
GIC restorations showed a superior preventive effect against secondary caries compared to amalgam restorations, and a similar preventive effect against secondary caries compared to resin-composite restorations in both primary and permanent teeth. [PROSPERO Registration ID: CRD42022380959]
Secondary caries around restorations is a major problem and can be attributed to bacteria invading microgaps formed at the tooth-restoration interface. An antibacterial composite resin containing quaternary ammonium silica (QASi) filler has been reported to inhibit enamel demineralization in situ. However, whether the prevention of enamel demineralization by QASi-containing composite resin is because of the reduced metabolic activity of acid-producing saliva bacteria is unclear.
The purpose of this study was to compare the effects of QASi-containing composite resin and 2 other restorative materials on the viability of salivary bacteria and sugar-induced acid production.
Whole saliva from each of the 30 study participants, 14 at high risk and 16 at low risk for caries, was brought into contact with quadruplicate specimens of 3 restorative materials, Infinix Flowable Composite, an anti-bacterial composite resin containing 1.5% QASi filler (Nobio), Filtek Supreme Flowable Restorative (3M), a conventional flowable composite resin, and dental amalgam (Silmet). Bacterial growth and sugar-induced acid production on each restorative material were measured every 20 minutes for 18 hours. Caries risk groups were compared using the t test and repeated measures analysis of variance (α=.05). When significant, Bonferroni multiple comparisons were used.
On average, the saliva with the QASi-containing composite resin specimens maintained a near-neutral pH, not dropping below pH 6.0. The saliva associated with both conventional restorative materials exhibited a pH drop below 5.5 (P<.001), the critical threshold for tooth demineralization according to the Stephan curve. Virtually no growth was measured on the surface of the antibacterial composite resin, whereas bacteria grew on the conventional composite resin and dental amalgam (P<.001). No differences were observed between participants at high and low risk of caries.
Unlike amalgam and conventional composite resin, the QASi-containing composite resin showed a near-complete shutdown of the metabolic activity of salivary bacteria upon contact and virtually no bacterial viability. This suggests that the prevention of tooth demineralization by QASi-containing restoratives is associated with a significant reduction in bacterial metabolic activity.
To provide the first review on cutting-edge research on the development of new bioactive restorations to inhibit secondary caries in enamel and dentin under biofilms. State-of-the-art bioactive and therapeutic materials design, structure-property relationships, performance and efficacies in oral biofilm models.
Researches on development and assessment new secondary caries inhibition restorations via in vitro and in vivo biofilm-based secondary caries models were included. The search of articles was carried out in Web of Science, PubMed, Medline and Scopus.
Based on the found articles, novel bioactive materials are divided into different categories according to their remineralization and antibacterial biofunctions. In vitro and in vivo biofilm-based secondary caries models are effective way of evaluating the materials efficacies. However, new intelligent and pH-responsive materials were still urgent need. And the materials evaluation should be performed via more clinical relevant biofilm-based secondary caries models.
Secondary caries is a primary reason for dental restoration failures. Biofilms produce acids, causing demineralization and secondary caries. To inhibit dental caries and improve the health and quality of life for millions of people, it is necessary to summarize the present state of technologies and new advances in dental biomaterials for preventing secondary caries and protecting tooth structures against oral biofilm attacks. In addition, suggestions for future studies are provided.
2023, Journal of the Mechanical Behavior of Biomedical Materials
The aim is to evaluate the development of an experimental multi-mode/Universal resin-based dentin adhesive modified with synthetic Mg2+ doped hydroxyapatite crystals (HAp) having self-remineralization and antibiofilm properties. HAp doped with Mg2+ was prepared by the precipitation method. Experimental adhesives were subjected to degree of conversion and X-ray diffraction test for size and crystal structure. Bond strength was tested, and electron microscopy (SEM/TEM) imaging of resin-dentin interface was done along with nanoleakage, nanoindentation, confocal and Raman analyses. S. mutans was analysed using CLSM images against modified adhesive specimens. Nucleating abilities within the resin-dentin specimens are determined by measuring Ca2+. Alkaline phosphatase, Runx2, and Ocn transcripts are amplified using quantitative polymerase chain reaction (q-PCR). A calcium assay is performed to quantify level of mineralisation. When compared to control adhesives, the 0.5% Hap/Mg2+ containing experimental dentin adhesive demonstrated improved interaction with dentin. The preservation of uniform intact hybrid layer with the absence of nanoleakage indicated dentin bond integrity with 0.5% HAP/Mg2+ modified adhesive. Self-remineralization and antibiofilm potentials are supported.
Studies suggested that presence and size of overhanging restoration margins play role in alveolar bone loss. The aim of this study was to determine the prevalence and distribution of overhanging approximal restorations, to evaluate the effect of presence and size of overhang on bone loss using cone beam computed tomography (CBCT) reformatted panoramic images, and to encourage the use of CBCT in retrospective studies on restorative dentistry.
CBCT images of 382 patients with approximal restorations were included in the study. On CBCT images, alveolar bone loss adjacent to each restored surface was determined and compared to the control tooth. The overhang size was measured and categorized as small, medium, or large. Data obtained were evaluated statistically using Kruskal Wallis, Mann Whitney U, chi-square, and one-sample chi-square tests with a significance level set at P < 0.05.
A total of 216 (32.4%) surfaces with overhanging restorations were detected in CBCT images. The number of overhanging surfaces with alveolar bone loss (71.3%) was higher than the control surfaces with bone loss (49.1%) (P < 0.05). The amount of bone loss adjacent to overhanging surfaces (2.28 ± 1.69 mm) was significantly higher compared to control surfaces (1.53 ± 1.73 mm) (P < 0.05). However, the same trend applied to the surfaces without overhang and their controls. The amount of bone loss was not correlated with the overhang size (P > 0.05).
Approximal restorations with and without overhanging margins may often result in alveolar bone loss, the amount of which is not always correlated with the overhang size.
This article was supported by grant DE13412 from the National Institutes of Health, National Institute of Dental and Craniofacial Research.
The illustrations in this article are all from the Operative Dentistry Clinic 2A, College of Dentistry, University of Florida. The treatments illustrated were performed by dental students and supervised by Dr. Mjör. Eduardo B. Mondragon photographed the clinical cases.
Dr. Mjör is a professor of Operative Dentistry and the Academy 100 Eminent Scholar, University of Florida College of Dentistry, P. O. Box 100415, Gainesville, Fla. 32610
