A six-year prospective randomized study of a nano-hybrid and a conventional hybrid resin composite in Class II restorations

Fatigue resistance of 3D printed anatomic post-and-core after mastication simulation

STATEMENT OF PROBLEM

Rigid post-and-core systems have traditionally been used in the restoration of endodontically treated teeth and are regarded by many as the standard treatment. Flexible materials, including nanoceramic resins, are being increasingly implemented as post-and-core systems, but data supporting their use are lacking.

PURPOSE

The purpose of this in vitro study was to compare the fatigue resistance of conventional cast metal and nanoceramic 3-dimensionally (3D) printed resin post-and-core systems with teeth without posts.

MATERIAL AND METHODS

Thirty freshly extracted human maxillary premolars were endodontically treated and divided into 3 subgroups (n=10) according to the restorative procedure: cast metal post-and-core (CM), nanoceramic 3D printed resin post-and-core (3DR), and without a post (0P). The CM post-and-core group was fabricated conventionally, while the 3DR group was printed using a 3D resin printing material. For the 0P group, the teeth were restored with a composite resin foundation after root canal obturation. Complete coverage 3-mol% monolithic zirconia restorations were cemented on all specimens. The specimens were exposed to simultaneous mastication simulation (1.2 million cycles) and thermocycling (10 000 cycles at 5 ºC to 55 ºC) and analyzed based on the failure of specimens. Data were analyzed using the Kruskal-Wallis survival analysis and the Wilcoxon rank sum test (α=.05).

RESULTS

The Kruskal-Wallis test indicated statistically significant differences among the cycles needed to reach failure for each of the 3 groups (P<.001). At 1.2 million cycles, there were no CM failures. The 3DR group failed at a median value of 950 000 cycles, while the 0P group failed at a median value of 222 500 cycles (P<.001).

CONCLUSIONS

All the endodontically treated teeth that received CM survived the 1 200 000 simulated mastication cycles. Both 3DR and 0P specimens fractured at the crown cervical third during mastication simulation.

Longevity of immediate rehabilitation with direct metal-wire reinforced composite fixed partial dentures

OBJECTIVES

This study aimed to analyze the longevity of direct metal-wire reinforced composite fixed partial dentures (MRC-FPD) and factors influencing their survival and success.

METHODS

Within one private practice 513 MRC-FPD were directly applied. The preparation of a proximal cavity in abutment teeth was not limited. MRC-FPD were reinforced by one to three metal-wires. At the last follow-up MRC-FPD were considered successful, if they were still in function without any need of therapy. MRC-FPD were considered as survived, if they were repaired or replaced. Multi-level Cox proportional hazard models were used to evaluate the association between clinical factors and time.

RESULTS

Mean follow-up period (range) was 59(2-249) months. Seventy-three bridges did not survive (cumulative survival rate(CSR):86%) and further 129 bridges had received a restorative follow-up treatment (CSR:61%). AFR was 2.2% for survival and 8.6% for success. In multivariate analysis MRC-FPD with> 1 wire showed a up to 2.3x higher failure rate than MRC-FPD with one wire(p ≤ 0.023). Dentist's experience in designing MRC-FDP (p ≤ 0.017), patient's caries risk (p ≤ 0.040) and bruxism (p = 0.033) significantly influenced the failure rate: the more experience, the lower caries risk and bruxism, the lower the failure rate.

SIGNIFICANCE

For directly prepared metal-wire reinforced composite bridges high survival and moderate success rates were observed. MRC-FPD might, thus, be an immediate, short- and medium-term solution for replacing missing teeth. However, several factors on the levels of practice (dentist's experience in designing MRC-FDP), patient (bruxism, caries risk) and restoration (number of wires) were identified as significant predictors for the failure rate. The study was registered in the German Clinical Trials Register (DRKS-ID: DRKS00021576).

Compliance of randomized controlled trials in posterior restorations with the CONSORT statement: a systematic review of methodology

OBJECTIVES

This study aims to investigate the compliance of randomized controlled trials (RCTs) in posterior restorations with the Consolidated Standards of Reporting Trials Statement (CONSORT) statement and to analyze the risk of bias (RoB) of these studies.

METHODS

A systematic search was performed in PubMed, Scopus, Web of Science, LILACS/BBO, and Cochrane Library. Only RCTs published in peer-reviewed journals were included. The compliance with the CONSORT was evaluated in a 0-2 scale where 0 = no description, 1 = poor description and 2 = adequate description. Descriptive analyses of the CONSORT mean score by journal, country, and RoB were performed. The RoB in RCTs was evaluated by using the Cochrane Collaboration's tool version 1.0.

RESULTS

A total of 15,476 studies were identified after duplicates removal. O only 202 meet the eligibility criteria, among which 31 were follow-up studies. Concerning the overall RoB, only 29 out of 171 were classified as low risk of bias. The overall mean CONSORT score was 19 ± 5.4 points, which means compliance of approximately 59%. Significant differences among countries, publication period, and RoB were observed (p < 0.001). The journal's impact factor was not correlated with the overall CONSORT score (p = 0.36).

CONCLUSIONS

The adherence of RCTs conducted in posterior restorations to the CONSORT Statement is still low. In addition, most studies were classified as at unclear risk of bias. These results call up an urgent need for improvement.

CLINICAL RELEVANCE

Most RCTs conducted in posterior teeth have poor reporting and are mainly classified as having an unclear risk of bias.

One-Year Clinical Performance of the Fast-Modelling Bulk Technique and Composite-Up Layering Technique in Class I Cavities

The aim of this study was to assess the one year clinical performance of a new application method, the Fast-Modelling Bulk Technique (FMBT), in comparison to the Composite-Up Layering Technique (CULT) in posterior cavities. Thirty patients with two class I cavities on permanent human molars were enrolled in the present study. A total of sixty class I cavities were prepared and randomly divided according to the restoration technique used: 30 cavities restored by incremental layering technique and modelling of the last layer with Composite-Up Technique (CUT) using the composite Filtek Z250XT (3M ESPE; St. Paul, MN, USA) and the other 30 restored by Bulk Filling technique and modelling of the last layer by Fast-Modelling Technique (FMT) using the composite Filtek Bulk Fill Posterior Restorative (3M ESPE; St. Paul, MN, USA). Restorations were evaluated for up to one year by two observers according to Federation Dentaire Internationale (FDI) criteria, through clinical and radiological exams. Exact Fisher tests were used for statistical analysis. (p ≤ 0.05). From a biological perspective, at baseline, teeth restored with both techniques did not reveal any postoperative sensitivity. However, with time, FMBT showed less postoperative sensitivity and therefore more desirable results than CULT with a nonsignificant difference after one year (p > 0.05). Concerning secondary caries, fracture of the material, and marginal adaptation, no significant difference was noted between both techniques (p > 0.05). Regarding marginal staining, CULT resulted in more staining with a significant difference, as compared to FMBT (p < 0.05). Upon radiological examination, FMBT showed a good marginal fit during the first year, whereas CULT showed small empty voids from baseline with a nonsignificant difference (p = 1.00). After one year of clinical function, both techniques showed promising results. The present study indicates that the new FMBT could have a positive effect on the marginal staining of resin composite.

Development of a Bioactive Flowable Resin Composite Containing a Zinc-Doped Phosphate-Based Glass

Flowable resins used for dental restoration are subject to biofilm formation. Zinc has antibacterial properties. Thus, we prepared a zinc-doped phosphate-based glass (Zn-PBG) to dope a flowable resin and evaluated the antibacterial activity of the composite against Streptococcus mutans (S. mutans) to extrapolate the preventative effect toward secondary caries. The composites were prepared having 0 (control), 1.9, 3.8, and 5.4 wt.% Zn-PBG. The flexural strength, elastic modulus, microhardness, depth of cure, ion release, inhibition zone size, and number of colony-forming units were evaluated and analyzed using ANOVA. The flexural strength of the control was significantly higher than those of Zn-PBG samples (p < 0.05). However, all samples meet the International Standard, ISO 4049. The microhardness was not significantly different for the control group and 1.9 and 3.8 wt.% groups, but the 5.4 wt.% Zn-PBG group had a significantly lower microhardness (p < 0.05). Further, the composite resins increasingly released P, Ca, Na, and Zn ions with an increase in Zn-PBG content (p < 0.05). The colony-forming unit count revealed a significant reduction in S. mutans viability (p < 0.05) with increase in Zn-PBG content. Therefore, the addition of Zn-PBG to flowable composite resins enhances antibacterial activity and could aid the prevention of secondary caries.

Nanofilled/nanohybrid and hybrid resin-based composite in patients with direct restorations in posterior teeth: A systematic review and meta-analysis

OBJECTIVE

A systematic review and a meta-analysis were performed to answer the following research question: Are there differences in the color match and surface texture of nanofilled/nanohybrid and hybrid composite in patients with direct posterior restorations?

DATA

Randomized clinical trials that compared nanofilled/nanohybrid and hybrid composite in direct restoration in posterior teeth were included. For the analysis of the bias the risk of bias tool (RoB) was used. Meta-analyses of different pairs (nanofilled vs. hybrid and nanohybrid vs. hybrid composite) were conducted for surface texture and color match and other secondary outcomes at different follow-ups, using a random effects model. Heterogeneity was assessed with the Cochran Q test and I² statistics. GRADE was used to assess the quality of the evidence.

SOURCES

A search was performed in PubMed, Scopus, Web of Science, LILACS, BBO, Cochrane Library and SIGLE, without restrictions. IADR abstracts (2001-2019), unpublished and ongoing trials registries, dissertations and theses were also searched.

STUDY SELECTION

28 studies remained. No study was considered to be at low RoB; four studies were judged to have high RoB, and the remaining were judged to have unclear RoB.

RESULTS

For the primary and secondary outcomes variables no significant differences were detected between nanofilled/nanohybrid restorations and hybrid composite restorations in any of the study follow-ups (p > 0.08). The body of evidence for surface texture and color match was classified as moderate or low.

CONCLUSION

No evidence of difference was found between nanofilled/nanohybrid and hybrid composite in any of the clinical parameters evaluated.

Risk Factors for Failure of Direct Restorations in General Dental Practices

The aim of this retrospective noninterventional multicenter practice-based study was to analyze factors influencing the survival of direct restorations. Records from patients who visited 5 private practices regularly were searched for the presence of direct restorations. Data were recorded from 7,858 patients with 27,407 direct restorations being detected at least 6 mo before the last recall visit. Multilevel Cox proportional hazard models were used to evaluate the association between clinical factors and time until failure. Within 228 mo, 5,493 failures could be observed. Median survival time was 207 mo. The annual failure rates were 3.8%, 4.0%, 4.6%, 4.9%, and 3.9% for class I, II, III, IV, and V restorations, respectively. Class II and IV restorations showed a 1.1-times (95% CI, 1.0 to 1.2) and 1.2-times (95% CI, 1.1 to 1.2) higher failure rate than class I restorations ( P ≤ 0.029). Patients aged <20 y and >60 y showed up to a 1.4-times higher failure rate than patients aged 20 to 60 y ( P ≤ 0.015). Restorations that underwent check-up twice a year or more showed a significantly higher failure rate than those that did so less than twice a year ( P < 0.001). Furthermore, the dentists significantly influenced time until failure ( P < 0.001). Regarding the restorative material, composites showed up to a 2.1-times longer time until failure than GIC ( P ≤ 0.020). Moderate failure rates were observed for direct restorations in the private practice setting after up to 18.5 y. Within the limitations of the present study, several factors on the levels of practice (i.e., dentist), patient (i.e., age), and tooth (i.e., restorative material, restored surfaces according to the classification of Black) were significant predictors for the failure rate. Therefore, treatment decision should take into account most relevant factors (German Clinical Trials Register DRKS00015228).

The differences between three performance measures on dental restorations, clinical success, survival and failure: A matter of perspective

OBJECTIVES

The aim of this retrospective methodology study was to investigate the influence of using different definitions for restoration failure and inclusion criteria on restoration longevity expressed in AFR.

METHODS

EPF from fifteen general dental practices were used for collecting the data for this study. From the EPF, 321,749 composite restorations placed in 52,245 patients by forty-seven GDPs between January 2000 and December 2011 were included. Kaplan-Meier statistics were applied and mean AFRs over 2, 5 and 10 years were calculated. The effect on the AFR of using different levels of failure: based on Claims data (CD), Success (SUC), Survival (SUR) and different inclusion criteria of tooth/restoration variables were reported.

RESULTS

Highest AFRs were found for level CD, in which every intervention was considered as failure, and the lowest AFRs for level SUR in which repairs and an endodontic treatments were not considered as a failure. AFRs increased when the observation period prolonged especially for SUR, followed by SUC and CD. An overview of long-term survival studies showed a wide variation in study design, performed clinical examination (USPHS criteria or GDP), number of restorations included, description of restoration failure and found AFRs for CD, SUC and SUR.

SIGNIFICANCE

Using failure criteria, Success and Survival, in future clinical studies would enable a better comparison of studies as well as demonstrate the impact of more conservative restorative intervention protocols on patient care.

In Vitro Caries Models for the Assessment of Novel Restorative Materials

Due to the high failure rates of traditional dental restorations, there is an ongoing effort to develop modified and new restorative biomaterials in dentistry. Being the most commonly used restorative material, most of these efforts primarily aim to improve dental composite. Generally, the main objective of such modifications is to enhance the restorative physical and antimicrobial properties in order to limit micro-leakage and inhibit bacterial biofilm cultivation. Herein, we describe the process of designing a simple in vitro model to assess the physical and antimicrobial properties of novel restorative materials in addition to evaluating their effect on the fragile balance between enamel de- and remineralization.

Clinical performance of bulk-fill and conventional resin composite restorations in posterior teeth: a systematic review and meta-analysis

OBJECTIVES

The purpose of this systematic review was to compare the clinical performance of bulk-fill resin composites with conventional resin composites used for direct restorations of posterior teeth.

METHODS

This review followed the PRISMA statement. This review was registered at PROSPERO (registration number CRD42016053436). A search of the scientific literature was performed by two independent reviewers using the PubMed/MEDLINE, Embase, The Cochrane Library, and Web of Science databases from commencement until January 2018. The research question was "Do bulk-fill resin composites have a clinical performance comparable to conventional resin composites in posterior restorations?" Only studies evaluating class I and II direct restorations in permanent teeth with a follow-up period of at least 1 year were included. The RevMan 5 program was used for meta-analysis, calculating the relative risk (RR) and 95% confidence interval (CI) of the dichotomous outcome (restoration failure or success).

RESULTS

Ten articles were selected, comprising 941 analyzed restorations. The mean follow-up period was 33.6 months (12-72 months). No statistically significant differences in the failure rate were observed between conventional and base/flowable bulk-fill resin composites (p = 0.31; RR 1.49; 95% CI 0.69-3.25) or full-body/sculptable bulk-fill resin composites (p = 0.12; RR 1.89; 95% CI 0.84-4.24).

CONCLUSIONS

The present systematic review and meta-analysis indicate similar clinical performances of bulk-fill and conventional resin composites over a follow-up period of 12 to 72 months.

CLINICAL SIGNIFICANCE

Based on the results of this study, the bulk-fill resin composites could be an alternative for direct restorations in posterior teeth. However, clinical trials of longer duration are required.

Do Nanofilled/Nanohybrid Composites Allow for Better Clinical Performance of Direct Restorations Than Traditional Microhybrid Composites? A Systematic Review

This systematic review was carried out to assess the clinical effectiveness of nanofilled and nanohybrid composites used for direct restorations in comparison with microhybrid composites. The guidelines for the preferred reporting items for systematic reviews and meta-analyses were followed. A search of articles published from July 1996 to February 2017 was performed in PubMed, SciVerse Scopus, Latin American and Caribbean Health Sciences, the Scientific Electronic Library Online, and the Cochrane Library. The present review selected only randomized controlled trials comparing the clinical performance of a nanofilled or nanohybrid composite for direct restorations with that of a microhybrid composite. The research found 201 studies. Twenty-one articles fulfilled the criteria of the present review. However, the included studies were characterized by great methodological diversities. As a general trend, nanofilled and nanohybrid composites were found to be capable of clinical performance, marginal quality, and resistance to wear similar to that of traditional composites without showing improved surface characteristics. The risk of bias of included studies was judged unclear or high. The clinical performance of nanofilled/nanohybrid composites was found to be comparable to that of traditional composites in the posterior area. The data concerning anterior and cervical restorations were insufficient. With regard to the esthetic properties, there is a compelling need for studies on anterior teeth in which the operators are kept unaware of the restorative material. Nanofilled/nanohybrid composites seem to be a valid alternative to traditional microhybrid composites, and at the moment, there is low-level evidence attesting a lack of their superiority.

Nanofilled Resin Composite Properties and Clinical Performance: A Review

The aim of this review was to compile recent evidence related to nanofilled resin composite materials regarding the properties and clinical performance. Special attention was given to mechanical properties, such as strength, hardness, abrasive wear, water sorption, and solubility. The clinical performance of nanocomposite materials compared with hybrid resin composites was also addressed in terms of retention and success rates, marginal adaptation, color match, and surface roughness. A search of English peer-reviewed dental literature (2003-2017) from PubMed and MEDLINE databases was conducted using the terms "nanocomposites" or "nanofilled resin composite" and "clinical evaluation." The list was screened, and 82 papers that were relevant to the objectives of this work were included in the review. Mechanical properties of nanocomposites are generally comparable to those of hybrid composites but higher than microfilled composites. Nanocomposites presented lower abrasive wear than hybrids but higher sorption values. Their clinical performance was comparable to that of hybrid composites.

Failure rate of single-unit restorations on posterior vital teeth: A systematic review

STATEMENT OF PROBLEM

No knowledge synthesis exists concerning when to use a direct restoration versus a complete-coverage indirect restoration in posterior vital teeth.

PURPOSE

The purpose of this systematic review was to identify the failure rate of conventional single-unit tooth-supported restorations in posterior permanent vital teeth as a function of remaining tooth structure.

MATERIAL AND METHODS

Four databases were searched electronically, and 8 selected journals were searched manually up to February 2015. Clinical studies of tooth-supported single-unit restorative treatments with a mean follow-up period of at least 3 years were selected. The outcome measured was the restorations' clinical or radiological failure. Following the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines, the Cochrane Collaboration procedures for randomized control trials, the Strengthening the Reporting of Observational Studies in Epidemiology criteria for observational studies, 2 reviewers independently applied eligibility criteria, extracted data, and assessed the quality of the evidence of the included studies using the American Association of Critical Care Nurses' system. The weighted-mean group 5-year failure rates of the restorations were reported according to the type of treatment and remaining tooth structure. A metaregression model was used to assess the correlation between the number of remaining tooth walls and the weighted-mean 5-year failure rates.

RESULTS

Five randomized controlled trials and 9 observational studies were included and their quality ranged from low to moderate. These studies included a total of 358 crowns, 4804 composite resins, and 303582 amalgams. Data obtained from the randomized controlled trials showed that, regardless of the amount of remaining tooth structure, amalgams presented better outcomes than composite resins. Furthermore, in teeth with fewer than 2 remaining walls, high-quality observational studies demonstrated that crowns were better than amalgams. A clear inverse correlation was found between the amount of remaining tooth structure and restoration failure.

CONCLUSIONS

Insufficient high-quality data are available to support one restorative treatment or material over another for the restoration of vital posterior teeth. However, the current evidence suggests that the failure rates of treatments may depend on the amount of remaining tooth structure and types of treatment.

Restoration Survival: Revisiting Patients' Risk Factors Through a Systematic Literature Review

A literature review was conducted to investigate the influence of patient-related factors on restoration survival in posterior permanent teeth as well as to report the methods used to collect these factors. The selection of articles on longitudinal clinical studies investigating the survival of posterior restorations (except full crowns and temporary fillings) and including patient-related factors was performed by applying predefined criteria. The review was organized into two parts, the first describing how patient factors were assessed in the studies (n=45) and the second presenting the statistical significance (n=27) and size of the effect (n=11) of these factors on restoration survival. Patient-related factors mentioned in the studies included age; gender; caries risk; caries activity/severity; decayed, missing, filled teeth; number of restorations; oral hygiene; and bruxism, among others. Sixteen studies included the patient age or age range in the analysis, which was found to be significant in 47% of the studies. Regarding gender, four of 17 reports found a significant effect on survival, showing more failures for men in three studies. The caries risk profile or related variables were included in the analysis of 15 studies, and a significant effect on survival was reported for high-caries-risk individuals (or related variables) in 67% of these studies. Bruxism was also found to influence restoration survival in three of six studies where this variable was investigated. Some issues were found regarding the reporting of methods used to classify patients according to risk and were thoroughly discussed. In view of the information gathered in this review, the assessment of patient factors along with other variables should become part of clinical studies investigating restoration survival, since several of these factors were shown to influence the failure of restorations, regardless of the material type.

A randomized controlled 27 years follow up of three resin composites in Class II restorations

OBJECTIVE

To evaluate the durability of three conventional resin composites in Class II restorations during 27 years.

METHODS

Thirty participants, 25 female and 5 male (mean age 38.2 years, range 25-63), received at least three (one set) as similar as possible Class II restorations of moderate size. The three cavities were chosen at random to be restored with a chemical-cured (Clearfil Posterior) and two visible light-cured resin composites (Adaptic II, Occlusin). A chemical-cured enamel bonding agent (Clearfil New Bond) was applied after Ca(OH)2 covering of dentin and enamel etch. Marginal sealing of the restorations was performed after finishing. One operator placed 99 restorations (33 sets). Evaluation was performed with slightly modified USPHS criteria at baseline, 2, 3, 10 and 27 years.

RESULTS

Postoperative sensitivity was observed in 5 patients. Three participants with 11 restorations (11%) could not be evaluated at the 27 year recall. Thirty-seven restorations failed (13 AII, 10 CP and 14 O). The overall success rate after 27 years was 56.5% (AII 55.2%, CP 63.0%, O 51.7%; p=0.70), with an annual failure rate of 1.6%. The main reason for failure was secondary caries (54.1%), followed by occlusal wear (21.6%) and material fracture (18.9%). Non-acceptable color match was seen in 24 (28.3%) of the restorations (AII 2, CP 16, O 6). Cox regression-analysis showed significant influence of the covariates tooth type, caries risk, and bruxing activity of the participants.

CONCLUSIONS

Class II restorations of the three conventional resin composites showed an acceptable success rate during the 27 year evaluation.

A randomized controlled 30 years follow up of three conventional resin composites in Class II restorations

OBJECTIVE

The aim of this 30 year randomized controlled study was to evaluate, by intraindividual comparisons, the durability of three conventional resin composites in Class II restorations.

METHODS

Each of 30 participants, 21 female and 9 male (mean age 30 years, range 20-43), received at least three (one set) as similar as possible Class II restorations of moderate size. After cavity preparation, the three cavities were chosen at random to be restored with two chemical-cured (P10, Miradapt) and one light-cured resin composite (P30). A chemical-cured enamel bonding agent was applied after etching of the enamel. The chemical-cured resin composites were placed in bulk and the light-cured in increments. One operator placed 99 restorations (33 sets). The restorations were evaluated with slightly modified USPHS criteria at baseline, 2, 3, 5, 10, 15, 20 and 30 years. Statistical analyses were performed by the Kaplan-Meier, log-rank test and Cox regression analyses.

RESULTS

After 30 years, 5 participants with 15 restorations (15%) could not be evaluated during the whole evaluation. Seven participants were considered as caries risk and eight participants as having active parafunctional habits. Postoperative sensitivity was observed in 24 teeth. In total 28 restorations, 9 P10, 12 P30 and 7 Miradapt restorations failed during the 30 years. The main reasons for failure were secondary caries (39.2%) and material fracture (35.7%). Sixty-four percent of the secondary caries lesions were found in high caries risk participants and 70% of the material fractures occurred in participants with active parafunctional habits. The overall success rate at 30 years was 63%, with an annual failure rate of 1.1%. 68-81% of the restorations showed non-acceptable color match. No statistical significant difference in survival rate was found between the three resin composites (p=0.45). The variables tooth type, cavity size, age, and gender of the participants did not significantly affect the probability of failure.

SIGNIFICANCE

The three conventional resin composites showed good clinical performance during the 30 year evaluation. The chemical cured resin composites showed better performance than the light-cured composite.

Physical Properties of an Ag-Doped Bioactive Flowable Composite Resin

The aim of this work was to study the physical and antibacterial properties of a flowable resin composite incorporating a sol-gel derived silver doped bioactive glass (Ag-BGCOMP). The depth of the cure was calculated by measuring the surface micro-hardness for the top and bottom surfaces. The volumetric polymerization shrinkage was measured by recording the linear shrinkage as change in length, while the biaxial flexural strength was studied measuring the load at failure. The antibacterial properties of the samples were tested against Streptococcus mutans (S. mutans) and Lactobacillus casei (L. casei). The measured values were slightly decreased for all tested physical properties compared to those of control group (flowable resin composite without Ag-BG), however enhanced bacteria inhibition was observed for Ag-BGCOMP. Ag-BGCOMP could find an application in low stress-bearing areas as well as in small cavity preparations to decrease secondary caries. This work provides a good foundation for future studies on evaluating the effects of Ag-BG addition into packable composites for applications in larger cavity preparations where enhanced mechanical properties are needed.

Survival characteristics of composite restorations in primary teeth

OBJECTIVES

This retrospective study analyzed restoration survival of composite fillings in children with at high caries risk in relation to age, sex, operator, tooth type, filling extension, and material used.

MATERIALS AND METHODS

Among 667 children treated in 2004-2012 in a university setting without sedation or general anesthesia, 2388 composite fillings were included. Relevant data from regular recall intervals were retrieved from patients' records. Either total-etch or a self-etch adhesive combined with flowable and/or (nano)hybrid composite was used. The Kaplan-Meier estimator and Cox proportional hazard analysis with backward elimination model were applied for survival analysis.

RESULTS

For the observation period of 8 years (mean 1.7 years), the cumulative failure rate was 17.2 % with annual failure rates of 10.0 %. In 8.8 % of the cases, fillings failed due to secondary caries. In 8.3 % technical failure due to total filling loss, loosening, marginal gaps, or tooth fracture occurred. Tooth type, filling extension, age, operator, dental dam, and type of adhesive were significant for survival (p < 0.05).

CONCLUSIONS

Filling survival was comparably lower to composite restorations observed in prospective clinical studies on permanent teeth and other tooth-colored restoratives used in primary teeth. Due to the very high caries risk and young age of the population, frequent loss due to secondary caries was observed. With respect to the high caries risk, composite restorations can be used to treat carious primary teeth, though a strict caries prevention regimen should be followed to minimize restoration failure.

CLINICAL RELEVANCE

Filling loss of composites in the primary dentition is associated with secondary caries on the long term.

Retrospective evaluation of posterior direct composite restorations: 10-year findings

OBJECTIVES

This 10-year retrospective study investigated the differences in the changes and the longevity of Class II restorations using 4 similar microhybrid resin composites (Filtek Z250, Herculite XR, Gradia Direct Posterior, Renew).

METHODS

Data were collected from patient records. Those patients who received posterior restoration between 2001 and 2003, and who still visited the clinical practice for regular check-up visits were selected. A total of 225 adult patients (86 males, 139 females) with 701 restorations were evaluated by 2 operators using the USPHS criteria. Data were analyzed with Fisher's Exact Test, Pearson's Chi-Square Test and Kaplan-Meier analysis (p<0.05).

RESULTS

A failure rate of 2.1% was detected. The reasons of failures included restoration fracture, secondary caries and endodontic treatment. Similar survival rates for Gradia Direct Posterior (91.25%) and Renew (92.19%) were observed; better performance was observed with the Filtek Z250 (99.1%) and Herculite XR (98.64%). There was a higher probability of failure in 3 surface (n=10) than in 2 surface (n=5) restorations (p<0.001), and this rate was similar when molars (n=8) and premolars (n=7) were compared. The most frequent but clinically acceptable deficiency was the marginal discoloration.

SIGNIFICANCE

All four microhybrid resin composites showed acceptable clinical durability in Class II restorations during the 10-year follow-up period, with an overall survival rate of >97.8%. Higher rates of failures and deficiencies were observed with the Renew (fracture) and Gradia Direct Posterior (color match), respectively.

Fabrication and characterization of bioactive and antibacterial composites for dental applications

There is an increasing clinical need to design novel dental materials that combine regenerative and antibacterial properties. In this work the characterization of a recently developed sol-gel-derived bioactive glass ceramic containing silver ions (Ag-BG) is presented. The microstructural characteristics, ion release profile, zeta potential value and changes in weight loss and pH value as a function of the immersion time of Ag-BG in Tris buffer are evaluated. Ag-BG is also incorporated into natural extracellular matrix (ECM) hydrogel to further enhance its regenerative properties. Then, the micro and macro architectures of these new composites (ECM/Ag-BG) are characterized. In addition, the antibacterial properties of these new composites are tested against Escherichia coli and Enterococcus faecalis, a bacterium commonly implicated in the pathogenesis of dental pulp infections. Cell-material interaction is also monitored in a primary culture of dental pulp cells. Our study highlights the benefits of the successful incorporation of Ag in the bioactive glass, resulting in a stable antibacterial material with long-lasting bactericidal activity. Furthermore, this work presents for the first time the fabrication of new Ag-doped composite materials, with inductive pulp-cell proliferation and antibacterial properties (ECM/Ag-BG). This advanced composite made of Ag-BG incorporated into natural ECM possesses improved properties that may facilitate potential applications in tooth regeneration approaches.

Factors affecting the placement or replacement of direct restorations in a dental school

Context:

The knowledge of the reasons for the placement of direct restorations makes possible to trace an epidemiological profile of a specific population and to direct the teaching of dentistry to techniques that are commonly used today and will be continued performed in the future.

Purpose:

The aim of this study was to verify the reasons for placement and replacement of direct restorations in patients treated in the Dental Clinic of the Uberaba University – Brazil.

Materials and Methods:

This study evaluated 306 restorative procedures carried out on 60 patients. During the treatment planning, a form that contained information about the patient's gender, tooth number, the classification of restorations, the reasons for placement and replacement of amalgam and tooth-colored restorations, the material that had to be removed and the new material used to fill the cavities was filled for each patient. Statistical analysis was carried out using Chi-square test (α = 0.05).

Results:

The data showed that most of the patients were female (66.7%). Of all the restorations placed, 60.45% were 1^st-time placements, while 39.55% were replacements. For 1^st-time restorations, the main reason for placement was primary caries (76.76%), followed by non-carious cervical lesions (15.14%). The amalgam restorations were replaced more frequently (67.77%). The primary reason for replacements was the presence of secondary caries (for both previous amalgam (42.68%) and composite (66.67%) restorations (P < 0.05). The resin composite was the most indicated material for the new restorations (98.04%) (P < 0.05).

Conclusions:

The main reason for placement of direct restorations was primary caries, while secondary caries was the main reason for replacements. In almost all cases, the material used to fill the cavities was the resin composite.