Restoration of noncarious cervical lesions: when, why, and how

Do bioactive materials show greater retention rates in restoring permanent teeth than non-bioactive materials? A systematic review and network meta-analysis of randomized controlled trials

OBJECTIVES

To answer the following research question: does the clinical evaluation of restorations on permanent teeth with bioactive materials show greater retention rates than those with non-bioactive materials?

MATERIALS AND METHODS

A search strategy was used in the following databases: MEDLINE via PubMed, Scopus, Web of Science, LILACS, BBO, Embase, The Cochrane Library, and OpenGrey. Randomized controlled trials (RCTs), with a minimum of 2-year follow-up and evaluating at least one bioactive material in permanent teeth were included. Risk of bias was detected according to the Cochrane Collaboration tool for assessing the risk of bias (RoB 2.0), and network meta-analysis was performed using a random-effects Bayesian-mixed treatment comparison model.

RESULTS

Twenty-seven studies were included. The success of the restorations was assessed using modified USPHS system in 24 studies and the FDI criteria in 3 studies. Network meta-analysis revealed three networks based on restoration preparations. Resin composites were ranked with higher SUCRA values, indicating a greater likelihood of being the preferred treatment for class I, II, and III restorations. In class V, resin-modified glass ionomer cement was ranked with the highest value.

CONCLUSION

Bioactive restorative materials showed similar good clinical performance in terms of retention similarly to conventional resin composites.

CLINICAL SIGNIFICANCE

The findings must be interpreted with caution because many RCT on restorative materials aim to verify the equivalence of new materials over the gold standard material rather than their superiority. The present systematic review also suggests that new RCT with longer follow-up periods are necessary.

Comparative Evaluation of Postoperative Sensitivity Using Three Different Tooth-Colored Restorative Materials in Non-carious Cervical Lesions: A Split-Mouth Design In Vivo Study

Introduction

Three different tooth-colored restorative materials were evaluated and compared for postoperative sensitivity using a split-mouth design. This is a double-blinded clinical trial assessed for a one-month follow-up period in patients with non-carious cervical lesions (NCCLs).

Materials and Methods

A total of 60 NCCLs in 20 participants were considered in this split-mouth design study and randomly divided into three different groups: Flowable composite (n = 20), resin-modified glass ionomer cement (RMGIC) (n = 20), and Zirconomer® (n = 20). The restorations were evaluated for postoperative sensitivity at baseline (BL-day 0), three, seven, and 21 days using the Schiff cold air sensitivity scale. Data were analyzed using IBM SPSS Statistics for Windows, Version 23.0 (Released 2015; IBM Corp., Armonk, New York, United States) using a post hoc test for postoperative sensitivity and one-way Anova to analyze all the groups together at the time interval of three, seven, and 21 days.

Results

In Group 1 (flowable composites) and Group 3 (Zirconomer), a statistically significant difference in terms of reduced postoperative sensitivity was seen after three and seven days. However, a significant reduction in postoperative sensitivity was seen after three, seven, and 21 days in Group 2 (RMGIC).

Conclusion

In this study, RMGIC showed reduced postoperative sensitivity after restoring NCCLs compared to Zirconomer and flowable composites. Compared with flowable composites and Zirconomer, RMGIC showed better clinical performance in terms of less postoperative sensitivity after restoring NCCLs.

Sixty-month follow up of three different universal adhesives used with a highly-filled flowable resin composite in the restoration of non-carious cervical lesion

OBJECTIVE

The purpose of this clinical trial was to evaluate and compare the performances of three different universal adhesives used with a highly filled flowable universal resin composite in the restoration of non-carious cervical lesions (NCCLs) over a 60-month period.

MATERIAL AND METHODS

Ninety-nine NCCLs were restored at 18 participants. NCCLs were divided into three different universal adhesive groups: Clearfil Universal Bond (CU) (n = 31), iBOND Universal (IU) (n = 33), and G-Premio Bond (GP) (n = 35). Prior to the adhesive procedures, selective enamel etching was performed with 37% phosphoric acid in all experimental groups. Adhesive systems were applied following the manufacturers' instructions, and the lesions were restored with a highly filled flowable resin composite (G-ænial Universal Flo). Restorations were finished and polished immediately after placement. All restorations were scored with regard to retention, marginal discoloration, marginal adaptation, sensitivity, surface texture, and color match using modified United States Public Health Service (USPHS) criteria after 1 week (baseline) and 6, 12, 18, 24, 36, and 60 months. Statistical analyses were performed using chi-square and McNemar's and Kaplan Meier tests. The level of significance was set at p < 0.05.

RESULTS

After 60 months, the recall rate was 72.2%. Survival rates of CU, IU, and GP restorations were 87%, 85.2%, and 96.5%, respectively. Five CU (25%), 8 IU (34.8%), and 12 GP (42.9%) restorations exhibit bravo scores for marginal adaptation. However, no differences were seen among them. CU showed lower bravo score than IU and GP for marginal discoloration (CU, 0%; IU, 26.1%; GP, 32.1%). Two CU, 7 IU, and 6 GP restorations showed bravo scores for surface texture, and 2 (9.1%) CU and 1 (3.3%) GP restorations were scored as bravo score for color match (p > 0.05).

CONCLUSION

The tested universal adhesives showed similar success rates during the 60-month follow-up. However, CU showed better clinical performance than IU and GP in terms of marginal adaptation and discoloration.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03415412 CLINICAL RELEVANCE: The long-term clinical performances of the three universal adhesives in the restoration of NCCLs using selective enamel etching mode were successful after 60 months.

Clinical Behavior of the Gingival Margin following Conservative “Coronally Dynamic” Restorations in the Presence of Non-Carious Cervical Lesions Associated with Gingival Recession: A Pilot Study

Gingival recessions (GR) are often associated with the presence of non-carious cervical lesions (NCCL). The latter result in the disappearance of the cement–enamel junction (CEJ), with consequent difficulties both in measuring the recession itself and in performing root coverage techniques. The restoration of cervical lesions is consequently an important aspect in the treatment of GR, with the re-establishment of a “new” CEJ. This pilot study aimed to verify whether restorative therapy alone, with the execution of a restoration that mimics the convexity of the natural CEJ and thanks to a slight horizontal over-contour, can stabilize a clot in the intrasulcular site and consequently is able to change the position of the gingival margin in a coronal direction. In periodontally healthy patients, with a non-thin gingival phenotype, 10 GR-associated NCCL restorations were performed using a protocol inspired by concepts of prosthetic conditioning, with a progressively reduced convexity (“coronally dynamic restoration”) and de-epithelialization of the gingival sulcus. We observed that 70% of the treated teeth showed a reduction in crown length after 15 days (−0.267 mm), without an increase in probing depth. While considering the limitations of the sample and the need to evaluate the different parameters that can affect the result, the coronally dynamic restoration of NCCL with GR was able to influence the position of the gingival margin in a coronal direction.

ISP Good Clinical Practice Recommendations for the management of Dentin Hypersensitivity

Dentin hypersensitivity (DH) is a rising concern in clinical dentistry that causes pain and discomfort and negatively affects the quality of life of patients. Indian Society of Periodontology conducted a nationwide survey, involving 3000 dentists in December 2020, which revealed significant knowledge gaps regarding DH, viz., under-diagnosis, incorrect differential diagnosis, and treatment strategies/recommendations for the management of DH patients in daily clinical practice. The current paper has been envisioned and conceptualized to update the practicing Indian dentists regarding the so-called enigma of dentistry “Dentin Hypersensitivity,” based on the best available contemporary evidence. An expert panel was constituted comprising 30 subject experts from across the country, which after extensive literature review and group discussions formulated these recommendations. The panel advocated routine screening of all dentate patients for exposed dentin areas and DH to avoid under-diagnosis of the condition and suggested an early preventive management. Consensus guidelines/recommendations for the use of desensitizing agents (DAs) at home, including the use of herbal agents, are also provided within the backdrop of the Indian context. The guidelines recommend that active management of DH shall be accomplished by a combination of at home and in-office therapies, starting with the simplest and cost-effective home use of desensitizing toothpastes. A diagnostic decision tree and a flowchart for application in daily practice are designed to manage the patients suffering from DH or presenting with exposed dentin areas in dentition. Various treatment methods to manage DH have been discussed in the paper, including the insights from previously published treatment guidelines. Further, a novel system of classification of DH patients based on specific case definitions has been developed for the first time. Explicit charts regarding the available treatment options and the chronology of institution of the agent, for the management in different case categories of DH, have been provided for quick reference. The management strategy takes into account a decision algorithm based on hierarchy of complexity of treatment options and intends to improve the quality of life of the patient by long-term maintenance with an innovatively defined triple C's or 3Cs approach.

Evaluation of Immediate and Delayed Microleakage of Class V Cavities Restored with Chitosan-incorporated Composite Resins: An In Vitro Study

Aim and objective

To evaluate and compare the microleakage of unmodified microhybrid composite and 0.2% chitosan-incorporated composite in class V cavities restored immediately and after 3 months of storage in artificial saliva.

Materials and methods

Sixty human permanent maxillary premolars were collected and standardized class V cavity prepared on the buccal surface of each tooth with dimensions: mesiodistally 3 mm, occluso cervically 2 mm, and depth of 1.5 mm and restored with microhybrid composite and chitosan-incorporated composite resins respectively and randomly divided: Group I: control-microhybrid composite (n = 30): (a) 15 teeth tested immediately (b) 15 teeth tested after 3 months. Group II–restored with chitosan + composite (n = 30): (a) 15 teeth tested immediately (b) 15 teeth tested after 3 months. Specimens were stored in artificial saliva following which a dye extraction test was carried out using a spectrophotometer.

Results

There was no statistically significant difference in microleakage score between the chitosan-composite group and unmodified composite group when evaluated immediately after placing the restoration. Microleakage values of the unmodified composite group increased significantly after 3 months of storage in artificial saliva and values of the chitosan-composite group did not differ significantly even after 3 months of storage. Microleakage was seen significantly less in the chitosan-composite group compared to the unmodified composite group after 3 months of storage in artificial saliva.

Conclusion

It can be concluded that chitosan-incorporated composite seems to have improved mechanical properties and forms a more stable bond when compared with unmodified microhybrid composite in addition to being antibacterial.

Clinical significance

Considering the advantageous properties of this material, it may be clinically useful in restoring class V cavities in patients with high caries risk. However, further in vitro and in vivo studies need to be carried out.

How to cite this article

Deb A, Pai V, Nadig RR. Evaluation of Immediate and Delayed Microleakage of Class V Cavities Restored with Chitosan-incorporated Composite Resins: An In Vitro Study. Int J Clin Pediatr Dent 2021;14(5):621–627.

B, Garoushi S. Fracture Behavior and Integrity of Different Direct Restorative Materials to Restore Noncarious Cervical Lesions

The purpose of this study was to analyze the fracture resistance and marginal leakage of noncarious cervical lesion (NCCL) restorations made of different restorative materials. Eighty upper premolars were randomly divided into four groups (n = 20/group). Standardized NCCL cavity preparations were performed on the buccal surface of the teeth and then restored with four different materials. Group 1: Packable resin composite (PC); Group 2: Highly flowable resin composite (HF); Group 3: Low flowable resin composite (LF); Group 4: Resin modified glass ionomer cement (RMGIC). After restorations were completed, cyclic and static fracture behavior was evaluated using a loading testing machine. Extra restored teeth were sectioned and then stained (n = 5/group). The specimens were viewed under a stereo microscope and the percentage of microgaps at the tooth–restoration interface was calculated. All restored teeth survived after fatigue loading. There was no statistically significant (p > 0.05) difference between the tested restorations after the static loading test. NCCLs restored with highly filled flowable composite showed the least microleakage among the tested groups (p < 0.05). The investigated restorative materials are acceptable for NCCL restorations in terms of fracture resistance and microleakage.

Evaluation of Microleakage of Micro Hybrid Composite Resins versus Chitosan-Incorporated Composite Resins When Restored in Class V Cavities Using Total Etch and Self-Etch Adhesives: An In vitro Study

Aim:

To evaluate the in-vitro microleakage of traditional micro hybrid composite resin and 0.2% chitosan-incorporated composite resin when restored in Class V cavities using total etch versus self-etch adhesives after storing in artificial saliva for 24 h.

Materials and Methodology:

Sixty permanent maxillary premolars collected and Class V cavities were prepared on buccal surface of each tooth (dimensions: mesio-distally 3 mm, occluso cervically 2 mm, and depth of 1.5 mm) and restored with Group 1: micro hybrid (30 teeth) and Group 2: chitosan-incorporated composite (30 teeth), which was further subdivided into: (a) 15 teeth using total-etch adhesives. (b) 15 teeth using self-etch adhesives. Next dye extraction test was carried out using spectrophotometer.

Results:

Comparison within groups: In Group 1: Self-etch demonstrated less microleakage (0.0129) compared with total etch (0.0183). The difference was statistically significant, and in Group 2: No statistically significant difference was found in mean microleakage scores after using either self-etch (0.0118) or total etch adhesives (0.0120).

Conclusion:

It can be concluded that chitosan-incorporated composite seems to have improved mechanical properties with a stable bond when used with either self-etch or total etch adhesives in addition to being antibacterial. It may be clinically useful in restoring Class V cavities in patients with high caries risk. However, further in vitro and in-vivo studies need to be carried out.

Adhesion of Flowable Resin Composites in Simulated Wedge-Shaped Cervical Lesions: An In Vitro Pilot Study

The resin composite restoration of non-carious cervical lesions (NCCLs) still faces some drawbacks mostly related to the quality of the marginal seal. This study attempts to evaluate the adhesive capacities of two flowable and two conventional hybrid resin composite restorations of NCCLs having two types of cervical margins. Our null hypothesis assumes the same adhesive behavior of different materials. The relative composition of dental–restoration structures was also measured. Thus, restored wedge-shaped cervical cavities were realized on both the buccal and oral surfaces of extracted teeth. After immersion in dye solution, sectioning of the teeth was performed. We proposed an optical microscopy method to quantify the dye penetration along the restoration–tooth interface and scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX) to evaluate the quality of the peripheral seal. The data obtained revealed an amount of dentinal microleakage for all tested materials, despite the favorable results of the restoration peripheral seal. Therefore, data from this study failed to reject the null hypothesis. The adhesion is not influenced by the position of cervical margins. The SEM revealed occasional disruptions of the adhesive interface. EDX sustains the qualitative compositions as provided by the manufacturers. Conclusions: The four experimental composites are recommended to restore NCCLs in clinic.

Randomized controlled clinical trial of a highly filled flowable composite in non-carious cervical lesions: 3-year results

OBJECTIVES

This prospective, randomized, split-mouth clinical trial assessed the 3-year clinical performance of a highly filled flowable composite and a conventional paste-type composite in non-carious cervical lesions (NCCLs).

MATERIALS AND METHODS

A total of 84 NCCLs in 27 subjects were included in this split-mouth design study and randomly divided into two groups: a highly filled flowable composite Clearfil Majesty ES Flow group (ES, n = 42) and a conventional paste-type composite Majesty group (MJ, n = 42). Clearfil SE Bond was used following the manufacturer's instructions. The restorations were evaluated at baseline (BL) and 1, 2, and 3 years using FDI (World Dental Federation) criteria. Data were analysed by a paired chi-squared test for intergroup comparisons and the Friedman test for intragroup comparisons (α = 0.05).

RESULTS

Both groups had a 97.3% retention rate at the 3-year evaluation. The acceptable scores (FDI scores 1-3) for each criterion exhibited no significant difference between the MJ and ES groups at any time point (p = 1.00). The marginal adaptation performance of ES was significantly better than that of MJ at every evaluation point (p < 0.05).

CONCLUSIONS

The 3-year clinical performance of ES in NCCLs was similar to that of MJ. When the restorations were clinically acceptable, ES showed better marginal adaptation than MJ.

CLINICAL RELEVANCE

Compared with conventional paste-type composites, highly filled flowable composites showed similar clinical performance and better marginal adaptation for restoring NCCLs after 3 years.

TRIAL REGISTRATION

TRN: ChiCTR1900028484 . Date of registration: December 22, 2019, retrospectively registered.

Finite element analysis of V-shaped tooth defects filled with universal nanohybrid composite using incremental technique

The aim of the present paper is to study the stresses and strains in fillings of V-shaped tooth defects made of universal photo-cured nanohybrid composite (UPC) using incremental technique. Numerical modeling with FEA and microleakage test are performed. Inhomogeneous distribution of the equivalent Von Mises stresses after polymerization of the two UPC layers is found, as the maximal value after polymerization of the first layer is 1.5 times lower compared to that of second one. In the first layer, maximum stresses are concentrated on dentin surface in cervical region of the obturation border and in occlusal region of the obturation volume. In the second layer, maximum stresses are generated in cervical area of the obturation volume and on dentin surface occlusally along the obturation border. The displacement after polymerization of each layer is inhomogeneous, as its values are more than 2 times smaller compared to that in fillings of glass-ionomer cement and flowable composite. In the first layer, the displacement is maximal on surface in the cervical region, while in the second layer it is maximal on surface occlusal of the obturation. The adequacy of the model used is confirmed by the microleakage test results. It is proven that UPC is better choice for filling of V-shaped defects due to the lower microleakage.

A comparative evaluation of the fracture resistance of endodontically treated teeth with simulated invasive cervical resorption cavities restored with different adhesive restorative materials: An in vitro study

Aim:

The aim of the study was to compare the fracture resistance of endodontically treated teeth with simulated invasive cervical resorption cavities, restored with different restorative materials, namely, conventional glass-ionomer cement (CGIC), resin-modified glass-ionomer cement (RMGIC), flowable composite (FC), and giomer.

Methods:

Sixty extracted human permanent maxillary central incisor teeth were assigned to six groups,which were, Group 1 (intact teeth, control), Group 2 (teeth with biomechanical preparation and resorption cavity), Group 3 (CGIC), Group 4 (RMGIC), Group 5 (FC), and Group 6 (giomer). Except for Group 1, other groups were subjected to endodontic treatment. Teeth of Group 2 were left unobturated and teeth of Groups 3–6 were obturated. A simulated resorption cavity was prepared labially in the specimens belonging to Groups 2–6 and restored with respective restorative materials. The specimens were subjected to compressive load until failure in an Instron testing machine and the load at failure was recorded in Newtons.

Statistical Analysis:

The data obtained were statistically analyzed using one-way ANOVA, pair-wise comparison was made with Tukey's multiple comparison test, and P < 0.05 was considered statistically significant.

Results:

There was a statistically significant difference in the fracture resistance of intact teeth and endodontically treated teeth with simulated invasive cervical resorption cavities restored with different adhesive restorative materials. Among the restored teeth, there was no significant difference.

Conclusion:

Intact teeth were found to have the highest resistance to fracture followed by those restored with giomer, FC, RMGIC, and CGIC in that order.

Effects of cervical restorations on the periodontal tissues: 5-year follow-up results of a randomized clinical trial

OBJECTIVE

This study evaluated the effect of resin composite restorations of non-carious cervical lesions (NCCLs) on the occurrence/progression of gingival recession (GR), considering different tooth isolation techniques.

METHODS

A randomized controlled split-mouth and blinded trial was carried out. Patients (n = 38) with at least two NCCLs were included. Before the cervical restoration placement, the NCCLs (181 teeth) were randomly allocated into two treatment groups according to the tooth isolation techniques: cotton roll or rubber dam. Experienced, trained, blinded, and calibrated examiners performed periodontal evaluations at baseline and 5-year follow-up, using a periodontal probe. Restorations were assessed with the FDI criteria. Thirty-two patients (154 teeth) were evaluated at 5 years. The occurrence/progression of GR between baseline and follow-up was considered the primary outcome. The relative risk (RR) and 95 % confidence interval (95 %CI) were calculated by Poisson regression (α < 0.05).

RESULTS

After 5 year, 31 teeth (13.6 %) presented occurrence/progression of GR. In the multivariate analyses, the occurrence/progression of GR was associated with the use of rubber dam isolation (RR; 95 %CI: 2.65; 1.01-7.00) and a lack of marginal adaptation of the restoration (RR; 95 %CI: 10.98; 2.31-52.30). Toothbrush stiffness, use of abrasive dentifrice, tooth type, and the presence of biofilm or gingivitis did not present a statistically significant higher risk for occurrence/progression of GR.

CONCLUSION

The use of rubber dam isolation associated with retraction clamp and the lack of a proper marginal adaptation of the composite restorations are risk indicators for the occurrence/progression of GR in individuals who received a restoration for an NCCL.

CLINICAL SIGNIFICANCE

Isolation with a rubber dam and dental clamps may promote GR in sites with restored NCCLs. Moreover, clinical examinations for lack of marginal adaptations of the restorations may be included in a clinical setting.

Composite restorations placed in non-carious cervical lesions-Which cavity preparation is clinically reliable?

The purpose of this in-vivo study was to evaluate the clinical performance of restorations placed in non-carious cervical lesions (NCCLs), using different cavity preparation designs, after 7.7 years. A total of 85 NCCLs with coronal margins in enamel and cervical margins in dentin were randomly assigned to the following treatment protocols: dentin surface cleaning, dentin surface roughening with round bur plus flowable composite, dentin surface roughening/cervical groove preparation with round bur, dentin surface roughening/cervical groove preparation with round bur plus flowable composite. After enamel beveling and selective enamel etching, the defects were restored with composite. The restorations were assessed by two independent, calibrated and blinded investigators, using modified USPHS criteria. At 7 years (7.7 (± 0.35)), a total of 64 restorations (75.3%) were available for follow-up examination. The total retention rate, irrespective of the test groups, was 82.8%. Restorations placed without any preparation showed the highest loss rate (27.8%). Esthetic appearance, marginal adaptation, anatomic form and marginal discoloration did not differ significantly between the groups. Composites are long-term stable materials for restoring NCCLs. Restorations placed without any dentin preparation (cavity cleaning only) showed the highest loss rate.

Do Tooth- and Cavity-related Aspects of Noncarious Cervical Lesions Affect the Retention of Resin Composite Restorations in Adults? A Systematic Review and Meta-analysis

PURPOSE

The purpose was to perform a systematic review and meta-analysis based on the following research question: do tooth- and cavity-related aspects of noncarious cervical lesions (NCCLs) affect the retention of composite restorations?

METHODS

Randomized clinical trials (RCTs) that evaluated the retention rate of resin restorations in NCCLs were included for the identification and comparison of their characteristics. The search was conducted in PubMed and adapted for Scopus, Web of Science, Latin American and Caribbean Health Sciences Literature database (LILACS), Brazilian Library in Dentistry (BBO), Cochrane Library, and System for Information on Grey Literature in Europe (SIGLE) without restrictions until July 2018. Unpublished and ongoing trial registries were also searched. The Cochrane Collaboration tool was used for assessing risk of bias. The quality of the evidence was graded using the Grading of Recommendations: Assessment, Development and Evaluation. Using the random effects model, a meta-analysis was conducted for each aspect (arch distribution, tooth location, wear facets, dentin sclerosis, shape, size, depth, occluso-gingival distance, and margin location).

RESULTS

We retrieved 6738 articles. After removal of duplicates and nonrelevant articles, 24 RCTs remained. The anterior tooth location favored the retention rates of restoration of NCCLs (relative risk [RR], 1.08; 95% confidence interval [CI], 1.00-1.16). The presence of wear facets is a risk factor for the retention of restorations (RR, 0.91; 95% CI, 0.83-0.99). The evidence was moderate for arch distribution and low or very low for all other factors because of heterogeneity, imprecision, and inconsistency.

CONCLUSION

The tooth location and the presence of wear facets can affect the retention of composite resins in NCCLs.

Clinical Evaluation of Noncarious Cervical Lesions of Different Extensions Restored With Bulk-fill or Conventional Resin Composite: Preliminary Results of a Randomized Clinical Trial

PURPOSE

This randomized clinical trial evaluated the influence of the occlusogingival distance (OGD) of noncarious cervical lesions (NCCLs) on the clinical performance of a regular bulk-fill resin composite and a regular nanofilled resin composite.

METHODS AND MATERIALS

A total of 140 restorations were randomly placed in 77 participants by one operator. NCCLs were divided into four groups (n=35) according to OGD (1.5 mm±10% or 3 mm±10%) and resin composites (Filtek Bulk Fill Posterior [B] or Filtek Z350 XT [C]) used: 1.5 mm-B, 1.5 mm-C, 3 mm-B, and 3 mm-C. A two-step self-etch adhesive (Clearfil SE Bond) was applied following manufacturer instructions in all restorative procedures. Restorations were polished 1 week after placement. Clinical evaluation was performed at baseline (7 days), 6 months, and 1 year by two calibrated examiners, according to the modified US Public Health Service criteria evaluating fractures/retention, marginal staining, marginal adaptation, recurrence of caries, anatomic form, postoperative sensitivity, and surface texture. The Kruskal-Wallis test was used for intergroup comparison in each follow-up; the Friedman analysis of variance, followed by the least significant difference test (multiple comparisons) was used for intragroup comparison between baseline and follow-up times (α=0.05).

RESULTS

Two restorations were lost at 12 months (1 for 1.5 mm-B and 1 for 3 mm-B). The retention rates at 12 months were 100% for 1.5 mm-C, 97% for 1.5 mm-B, 100% for 3 mm-C; and 97% for 3 mm-B, with no statistical difference among the groups (p=0.570). At 12 months, a statistically significant difference was found among the follow-up times for the same group (1.5 mm-B, 1.5 mm-C, and 3 mm-B) regarding the marginal staining criterion; moreover, the 3 mm-C group showed a significant difference from 6 months. No significant difference was found for the other parameters.

CONCLUSION

Both resin composites showed acceptable clinical performance, and the OGD of NCCLs did not influence the clinical performance of resin composite restorations after 12 months.

A 2-year clinical evaluation of direct and semi-direct resin composite restorations in non-carious cervical lesions: a randomized clinical study

OBJECTIVES

The purpose of this study was to evaluate the 2-year success of resin composite restorations in non-carious cervical lesions (NCCLs) using the direct or semi-direct techniques.

MATERIALS AND METHODS

Thirty volunteers presenting with at least two NCCLs were included. Each participant received one restoration using the direct technique and the other using the semi-direct technique, totaling 60 restorations. Time for completing the treatment was computed. Assessments at baseline, 7 days, and 6, 12, and 24 months were performed using the modified United States Public Health Service criteria. Descriptive analysis was reported as a percentage of successful treatments. For inferential analysis, the Student t test was used to evaluate the differences between extension, depth, and time. The chi-square/Fisher tests were used to compare treatment success after each period (α = 0.05). The results were evaluated by using the Kaplan-Meier survival analysis.

RESULTS

Differences were detected regarding mean ± standard deviation time, in which direct and semi-direct procedures were accomplished in 21.8 (± 14.5) and 35.3 (± 19.9) min, respectively. Of the 60 restorations placed, 7 failed in the direct group while 8 failed in the semi-direct group up to 2 years. No differences were detected between restorative protocols. The cumulative survival was 88.5% and 88.4% for the direct technique and semi-direct techniques after 24 months, respectively.

CONCLUSION

The tested restorative protocols present similar results for NCCLs within the studied periods.

CLINICAL RELEVANCE

The semi-direct technique exhibited clinical performance similar to direct technique for NCCL, demonstrating an alternative for restorations of these lesions.

Investigations on the adhesion of new composites for restoring cervical lesions using energy dispersive X-ray analysis and scanning electron microscopy

Restoration of noncarious cervical lesions with resin composites is one of the treatment options, but the retention of the restorations located at the crown-root junction is still a cause of clinical concern. The aim of this study was to evaluate the adhesive properties of three experimental resin composites and two commercial materials used to restore cavities prepared on extracted teeth as well as to determine the relative elemental composition of these materials. We tested the null hypothesis, which considered that the adhesive behaviours of different resin composites did not differ. The microleakage test using tracers showed that all tested materials exhibited some degree of dentinal microleakage, although they all had good dentinal adhesion. The results failed to reject the null hypothesis. The scanning electron microscopy revealed completely adapted adhesive interfaces underneath the restorations along with well-developed hybrid layers depending on the adhesive system. Energy dispersive X-ray analysis analyses showed that the restorative materials have similar chemical compositions, with some differences between the samples from the same material. The results support the implementation of experimental resins in clinical settings.

Composite vs. ionomer vs. mixed restoration of wedge-shaped dental cervical lesions: Marginal quality relative to eccentric occlusal loading

Dental cervical restorations may be impacted by resultants of occlusal loads that may have already contributed to the development of the lesion and should rely on materials' favorable properties to bear the stresses. The marginal quality of cervical restorations made with materials of different moduli of elasticity in essence, isolated, or in combination, was evaluated relative to eccentric occlusal loading. Cervical wedge-shaped cavities, prepared in extracted premolars, were restored with a composite resin (CR), a restorative ionomer (GIC), or the composite in combination with a lining ionomer (Mixed restoration: M). Half of the teeth in each group were subjected to eccentric occlusal loading (eol; 150 N / 10⁶ cycles / 2.5 Hz; CReol / GICeol / Meol, n = 10), and the others were stored in 37 °C distilled water (Control: c; CRc / GICc / Mc, n = 10). A fluorescein-modified adhesive favored delimitation of formed gaps, which were evaluated by confocal laser scanning microscopy regarding their presence, location related to the cavity walls, and width and depth (µm), at a 5% significance level. From a comprehensive perspective, neither the loading nor the materials were significantly associated with the qualitative response variables or exerted any influence over the quantitative variables. More specifically, the use of the different materials was significantly associated with the frequency of gaps exclusively when loading was applied (Chi-square test, p = 0.029, CR > M > GIC). Though the marginal quality of cervical restorations may not be influenced by eccentric occlusal loading or the use of different materials, even in association in general, the unfavorable aspects of the use of the composite may be relevant, particularly in face of the existence of eccentric occlusal loads.

A Simple Method for Treating Subgingival Class V Lesions

Noncarious cervical lesions (NCCLs) are steadily increasing. Unfortunately, NCCL restorations represent one of the less durable types of restorations due to problems, including isolation and crevicular moisture control, especially in cases where the cervical margin is covered by soft tissue. This article presents a technique that allows us, through the use of a common metallic matrix, to isolate and make accessible class V cavities with intrasulcular cervical margins. The advantages and disadvantages of the technique are presented.

Chemical Interaction and Interface Analysis of Self-Etch Adhesives Containing 10-MDP and Methacrylamide With the Dentin in Noncarious Cervical Lesions

Objectives:

To characterize the chemical interactions and analyze the interface of adhesive systems containing 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) and N-methacryloyl glycine (methacrylamide) functional monomers with the dentin in noncarious cervical lesions (NCCLs) compared with artificial defects (ADs).

Methods and Materials:

Twenty human teeth with natural NCCLs on the buccal surface were used. Class V cavities, similar to NCCLs, were created on the lingual surface to serve as controls. Teeth were randomly allocated to two groups according to the functional monomer in the adhesive (N=10): G1, 10-MDP; and G2, methacrylamide. NCCLs and ADs were characterized by their mineral composition (MC) and degree of demineralization (DD) using micro-Raman spectroscopy, adhesive/dentin chemical interactions (CIs) were assessed with infrared photoacoustic spectroscopy, and interface morphology was evaluated with scanning electron and light microscopy. MC, CI, and DD data were submitted to Shapiro-Wilk and Student t-tests (p&lt;0.05).

Results:

Compared with ADs, dentin in NCCLs was hypermineralized (p&lt;0.05). In G1, CI, and DD in the first 2 μm, and adhesive projections in NCCLs and ADs interfaces were similar. Additionally, a thin layer of dentin collagen was observed in ADs, while it was hardly present in NCCLs. In G2, although CI could not be identified, changes in the mineral components were observed. The DD in the ADs and NCCLs were statistically similar, while SEM showed a lack of adhesion at NCCLs interface. DD and collagen exposure in the ADs and NCCLs were more pronounced than in G1.

Conclusions:

Results suggest that the G1 adhesive could be applied directly on the superficial sclerotic layer in NCCLs. In contrast, previous cavity preparation should be conducted to improve the micromechanical interaction of G2 with the dentin.

Recent advances in understanding the fatigue and wear behavior of dental composites and ceramics

Dental composite and ceramic restorative materials are designed to closely mimic the aesthetics and function of natural tooth tissue, and their longevity in the oral environment depends to a large degree on their fatigue and wear properties. The purpose of this review is to highlight some recent advances in our understanding of fatigue and wear mechanisms, and how they contribute to restoration failures in the complex oral environment. Overall, fatigue and wear processes are found to be closely related, with wear of dental ceramic occlusal surfaces providing initiation sites for fatigue failures, and subsurface fatigue crack propagation driving key wear mechanisms for composites, ceramics, and enamel. Furthermore, both fatigue and wear of composite restorations may be important in enabling secondary caries formation, which is the leading cause of composite restoration failures. Overall, developing a mechanistic description of fatigue, wear, and secondary caries formation, along with understanding the interconnectivity of all three processes, are together seen as essential keys to successfully using in vitro studies to predict in vivo outcomes and develop improved dental restorative materials.

Stress distribution in endodontically treated abfracted mandibular premolar restored with different cements and crowns: A three-dimensional finite element analysis

Context

Noncarious cervical lesions may penetrate the pulp and require root canal treatment followed by crown placement. Such teeth may be susceptible to fracture, especially at the cervical area.

Aims

To estimate which combination of restorative material and crown resulted in homogenous stress-strain distribution of endodontically treated abfracted mandibular premolar using three-dimensional finite element model (FEM).

Settings and Design

A three-dimensional model of mandibular single-rooted premolar along with alveolar bone was created in finite element analysis (FEA) software preprocessor ANSYS rel 14.5 FEM software (ANSYS Inc., Houston, USA, 1994). Cervical lesion was created in the model with specific dimensions, 3 mm mesiodistally and 2 mm gingivoocclusally with enamel occlusal margin and dentin gingival margin.

Materials and Methods

Tooth was simulated to be root canal treated and restored with different types of cements and crowns followed by placing a static load of 300 N at an angle of 135°. Analysis was run and stress distribution pattern was studied.

Results

Cervical region of an endodontically treated tooth is subjected to stresses, irrespective of restorative material used. Porcelain fused to metal (PFM) crowns showed least strain values with different postendodontic, restorative materials.

Conclusions

FEA is a predictable and reproducible model to predict stress-strain behavior. PFM crowns with different postendodontic restorative materials showed least strain values in the cervical area of abfracted, endodontically treated premolars.

Chemical Interaction Analysis of an Adhesive Containing 10-Methacryloyloxydecyl Dihydrogen Phosphate (10-MDP) With the Dentin in Noncarious Cervical Lesions

The purpose of this study was to evaluate the chemical bonds of a self-etch 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) adhesive to natural noncarious cervical lesions (NCCLs) and compare them with those occurring in sclerotic dentin in artificially prepared defects (APDs). Four human teeth with natural NCCLs on the buccal surface were selected. Artificial defects matching the natural lesions were prepared on the lingual surface of the same teeth serving as control. Micro-Raman (MR) spectroscopy was used to quantify mineral content in natural NCCLs and in APDs. Fourier transform infrared-photoacoustic spectroscopy (FTIR-PAS) readouts were taken before and after adhesive application to analyze the protein matrix/mineral (M:M) ratio and chemical interactions between 10-MDP adhesive and dentin. The MR and FTIR-PAS spectra collected from natural NCCLs demonstrated a larger area of the band (961 cm−1, PO4) and lower M:M ratio, respectively, characterizing a hypermineralized dentin, compared with APDs. FTIR-PAS demonstrated emergence of a peak (1179 cm−1, P=O) in spectra after adhesive treatment, demonstrating a more intense chemical interaction in natural NCCLs. The results demonstrated that chemical bonding of 10-MDP adhesive to natural NCCLs is more intense, due to the hypermineralized surface, and suggest that it is unnecessary to remove the hypermineralized layer with burs, as this may decrease the chemical bonding potential of 10-MDP.

Effectiveness of pre-treatment with chlorhexidine in restoration retention: A 36-month follow-up randomized clinical trial

OBJECTIVES

This study evaluated the effect of the pre-treatment with 2% chlorhexidine digluconate (CHX) as coadjutant in restoration retention of noncarious cervical lesions (NCCL), after 36 months of follow-up.

METHODS

A randomized controlled split-mouth and triple-blind (operators, patients and evaluator) trial was carried out. Patients (n=42) with at least two non-carious cervical lesions were included. The teeth with NCCL were randomly assigned to two treatment groups: application of 2% CHX (experimental group) or a placebo solution (control group) for 60s after acid etching and before the adhesive application. A trained and calibrated examiner evaluated the restorations at baseline (1 week) and at each recall (6, 12, 24 and 36 months) using the FDI criteria. A total of 225 restorations were evaluated after 36-month follow-up. Data were subjected to survival analysis using the Kaplan-Meier method, and the log-rank test was used to evaluate the existence of differences between the survival curves (α=0.05).

RESULTS

The restorations survival rate after 36 months of follow-up was 76.1%. There was no difference in the retention and failure rates between the experimental and the control group (p=0.968). There was an increased failure trend when restorations were located subgingival compared to those at the gingival level or supragingival.

CONCLUSION

The pre-treatment with 2% chlorhexidine digluconate did not promote further restoration retention of noncarious cervical lesions.

CLINICAL SIGNIFICANCE

The cavity pre-treatment with chlorhexidine for inhibition of hybrid layer degradation does not add any beneficial effect to the clinical performance of restorations.

Flowable composites for restoration of non-carious cervical lesions: Three-year results

OBJECTIVES

To evaluate the clinical performance of two flowable composites for restoring Class-V non-carious cervical lesions (NCCLs), one with novel (ND; N'Durance^® Dimer Flow, Septodont) and one with modified conventional matrix composition (FS; Filtek™ Supreme XTE Flow, 3M-ESPE). The null hypothesis was that both flowable composites perform equally regarding clinical quality and survival.

METHODS

50 patients received one ND and one FS restoration of NCCLs in premolars using Clearfil Protect Bond (Kuraray) as an adhesive. Restorations were evaluated by two examiners at baseline (BL), 18 and 36 months employing FDI criteria. Non-parametric statistical analyses and χ² tests were applied (α=0.05).

RESULTS

48 patients with both restorations under risk participated in the 36-mo recall. One patient terminated participation after the 18-mo recall. One ND restoration failed at the 18-mo recall (fracture). One FS restoration failed during clinical examination at the 36-mo recall (debonding). 95.8% of restorations each were rated clinically acceptable at 36-mo. No significant differences for all selected FDI criteria were recorded between ND and FS at each examination time point except for the criteria surface staining at 36-mo and marginal staining at 18-mo and 36-mo, where FS showed significantly better results. For each material, no significant differences over time were detected, except for loss of surface lustre for FS (BL to 18 months).

SIGNIFICANCE

Within the limitations of the study, the null hypothesis that materials perform equally could not be rejected. Both flowable composites performed equally regarding survival and similarly regarding clinical performance.

One-year comparative evaluation of Ketac Nano with resin-modified glass ionomer cement and Giomer in noncarious cervical lesions: A randomized clinical trial

Aim:

The purpose of this study was to evaluate the clinical performance of Ketac Nano (Ketac™ N100), RMGIC (Fuji Filling™ LC), and Giomer (Beautifil^® II) in noncarious cervical lesions (NCCLs).

Materials and Methods:

One operator restored 120 NCCLs in 20 subjects, with at least two lesions restored with one of the restorative materials: RMGIC (control group), Giomer and Ketac Nano (experimental groups). Two observers evaluated retention, marginal discoloration, marginal adaptation, color match, surface roughness, and postoperative sensitivity using modified USPHS criteria at baseline, 6, and 12 months.

Study Design:

Double-blinded randomized clinical trial (RCT).

Statistical Analysis:

Kruskal–Wallis test, Mann–Whitney U-test, Wilcoxon matched-pairs test.

Results:

There was statistically significant difference observed between Giomer, Ketac Nano and RMGIC after 12 months (P < 0.05). There was a significant decrease in retention rates for Giomer (P = 0.0050), increased marginal discoloration and color mismatch for Ketac Nano (P = 0.0025, P = 0.0053), increased surface roughness and color mismatch with RMGIC (P = 0.0022, P = 0.0077) from baseline to 12 months.

Conclusion:

Within the limitations of this RCT of 12 months, Ketac Nano and RMGIC restorations were better retained in NCCLs while superior color match and surface finish were observed with Giomer restorations.

One year comparative clinical evaluation of EQUIA with resin-modified glass ionomer and a nanohybrid composite in noncarious cervical lesions

Aims:

Comparative evaluation of EQUIA with a resin-modified glass ionomer cement (RMGIC; GC Gold Label glass ionomer light cured universal restorative cement) and a nanohybrid composite (Tetric N-Ceram) in noncarious cervical lesions (NCCLs).

Background:

To establish the most suitable material for the restoration of NCCLs.

Settings and Design:

In vivo study.

Materials and Methods:

Eighty-seven NCCLs were randomly restored with EQUIA, a RMGIC, and a nanohybrid composite. Clinical evaluation of the restorations was done following the Unites States Public Health criteria by a single-blinded investigator. Data were formulated, and statistical analysis was done by Chi-square test.

Statistical Analysis Used:

Chi-square test.

Results:

No significant difference was found between EQUIA, RMGIC, and nanohybrid composite at 1-month, at 6 months, and at 1-year (P > 0.05).

Conclusions:

EQUIA, resin-modified glass ionomer, and nanohybrid composite performed equally at 1-month, 6 months, and 1-year follow-up periods.

Magnitude and distribution of stresses in composite resin and sound dentine interface with mechanical retentions

Background

Adhesive systems are constantly subjected to mechanical and chemical stresses that negatively impact the integrity and durability of the dentine-adhesive interface. Despite the lack of evidence to support or reject the clinical indication for mechanical retention, the potential further contribution of these preparations to the behavior of the composite resin-sound dentine bond has been rarely addressed. The authors evaluated by finite element analysis the effect of mechanical retention on the magnitude and distribution of stresses in a composite resin-sound dentin bonding interface when subjected to tensile and shear forces.

Material and Methods

A three-dimensional model was created based on three cylindrical volumes representing the sound dentin, adhesive system, and composite resin. From this main model, two models were designed to simulate dentine bonding: 1) a model with no mechanical retention, which considered flat adhesion; and 2) a model with retention, which considered four hemispherical holes on the dentine surface. Both groups were subjected to linear static analysis under tensile and shear loading of 200N.

Results

At the model with retentions’ bonding interface under tensile and shear loading, a concentration of Von Mises equivalent stress was observed within the retentions, with a reduction of those stresses on the bonding boundary surface.

Conclusions

Additional mechanical retention increases the tensile strength of the sound dentin-composite resin bonding interface, promoting a decrease in the magnitude of the stresses and their redistribution under tensile and shear loading.

Key words:Adhesion, composite resins, dentine, finite element analysis.

The evolutionary paradox of tooth wear: simply destruction or inevitable adaptation?

Over the last century, humans from industrialized societies have witnessed a radical increase in some dental diseases. A severe problem concerns the loss of dental materials (enamel and dentine) at the buccal cervical region of the tooth. This “modern-day” pathology, called non-carious cervical lesions (NCCLs), is ubiquitous and worldwide spread, but is very sporadic in modern humans from pre-industrialized societies. Scholars believe that several factors are involved, but the real dynamics behind this pathology are far from being understood. Here we use an engineering approach, finite element analysis (FEA), to suggest that the lack of dental wear, characteristic of industrialized societies, might be a major factor leading to NCCLs. Occlusal loads were applied to high resolution finite element models of lower second premolars (P₂) to demonstrate that slightly worn P₂s envisage high tensile stresses in the buccal cervical region, but when worn down artificially in the laboratory the pattern of stress distribution changes and the tensile stresses decrease, matching the results obtained in naturally worn P₂s. In the modern industrialized world, individuals at advanced ages show very moderate dental wear when compared to past societies, and teeth are exposed to high tensile stresses at the buccal cervical region for decades longer. This is the most likely mechanism explaining enamel loss in the cervical region, and may favor the activity of other disruptive processes such as biocorrosion. Because of the lack of dental abrasion, our masticatory apparatus faces new challenges that can only be understood in an evolutionary perspective.