Tamara Kerber Tedesco

Chlorhexidine does not increase immediate bond strength of etch-and-rinse adhesive to caries-affected dentin of primary and permanent teeth

The aim of this study was to evaluate the effect of 2% chlorhexidine digluconate (CHX) on immediate bond strength of etch-and-rinse adhesive to sound (SD) and caries-affected (CAD) primary dentin compared with permanent dentin. Flat dentin surfaces from 20 primary molars (Pri) and 20 permanent molars (Perm) were assigned to 8 experimental groups (n=5) according to tooth type (Pri or Perm), dentin condition (SD or CAD - pH-cycling for 14 days) and treatment (control - C or 60 s application of 2% CHX solution after acid etching - CHX). The bonding system (Adper Single Bond 2) was applied according to manufacturers instructions followed by resin composite application (Filtek Z250). After 24 h water storage, specimens with cross-section area of 0.8 mm² were prepared for being tested under microtensile test (1 mm/min). Data were submitted to ANOVA and Tukeys post hoc test (α=0.05). Failure mode was evaluated using a stereomicroscope at ×400. Treatment with CHX did not result in higher bond strength values than no pre-treatment (C groups), independently of tooth type. Primary teeth and caries-affected dentin showed significantly lower (p<0.05) bond strength means compared with permanent teeth and sound dentin, respectively. Predominance of adhesive/mixed failure was observed for all groups. CHX did not influence the immediate bond strength to sound or caries-affected dentin of primary and permanent teeth.

Eroded dentin does not jeopardize the bond strength of adhesive restorative materials

This in vitro study evaluated the bond strength of adhesive restorative materials to sound and eroded dentin. Thirty-six bovine incisors were embedded in acrylic resin and ground to obtain flat buccal dentin surfaces. Specimens were randomly allocated in 2 groups: sound dentin (immersion in artificial saliva) and eroded dentin (pH cycling model - 3× / cola drink for 7 days). Specimens were then reassigned according to restorative material: glass ionomer cement (KetacTM Molar Easy Mix), resin-modified glass ionomer cement (VitremerTM) or adhesive system with resin composite (Adper Single Bond 2 + Filtek Z250). Polyethylene tubes with an internal diameter of 0.76 mm were placed over the dentin and filled with the material. The microshear bond test was performed after 24 h of water storage at 37ºC. The failure mode was evaluated using a stereomicroscope (400×). Bond strength data were analyzed with two-way ANOVA and Tukeys post hoc tests (α = 0.05). Eroded dentin showed bond strength values similar to those for sound dentin for all materials. The adhesive system showed the highest bond strength values, regardless of the substrate (p < 0.0001). For all groups, the adhesive/mixed failure prevailed. In conclusion, adhesive materials may be used in eroded dentin without jeopardizing the bonding quality. It is preferable to use an etch-and-rinse adhesive system because it shows the highest bond strength values compared with the glass ionomer cements tested.

ART is an alternative for restoring occlusoproximal cavities in primary teeth - evidence from an updated systematic review and meta-analysis.

BACKGROUND A previous systematic review showed that atraumatic restorative treatment (ART) can be an option to restore the occlusoproximal cavities in primary teeth; however, few studies fulfilled the criteria of inclusion to generate a high level of evidence. AIM To update the existing systematic review and address questions regarding survival rate of ART restorations compared to the conventional approach in occlusoproximal cavities in primary molars. DESIGN The search was extended beyond the original search through the PubMed/MEDLINE database up to February 2016. Furthermore, Web of Science and EMBASE were searched. The inclusion criteria were subjects related to the scope of the systematic review. After selection by title and abstract, potentially eligible articles were read in full and included in accordance with exclusion criteria. Meta-analysis was carried out with the outcome being the survival rate of restorations. RESULTS The search strategy identified 560 potentially relevant studies, in addition to 127 from the original systematic review. A total of four articles were included in the qualitative and quantitative analyses. Meta-analysis showed no statistically significant difference between ART and conventional approaches in survival rate of occlusoproximal cavities (OR = 0.887, 95% CI: 0.574-1.371). CONCLUSION ART restorations have similar survival rate compared to conventional treatment and can be considered an option to restore occlusoproximal cavities in primary molars.

Does the method of caries induction influence the bond strength to dentin of primary teeth

PURPOSE To evaluate the effect of chemical and microbiological methods of caries induction on microtensile bond strength (μTBS) of current adhesive systems to primary dentin. MATERIALS AND METHODS Flat dentin surfaces from 36 primary molars were assigned to 3 groups according to the method of inducing caries-affected dentin: (1) control (sound dentin); (2) pH cycling; and (3) microbiological. In both methods, teeth were submitted to caries induction for 14 days, and the sound dentin was stored in distilled water for the same period. Specimens were then randomly reassigned according to adhesive system: a two-step etch-and-rinse adhesive (Adper Single Bond 2) or a two-step self-etching system (Clearfil SE Bond). Composite buildups were constructed and the teeth were sectioned to obtain bonded sticks (0.8 mm2) to be tested for microtensile bond strength. The μTBS means were analyzed by two-way ANOVA and Tukeys tests (α = 0.05). Failure mode was evaluated using a stereomicroscope (400X). RESULTS Both methods of caries induction resulted in lower μTBS values (with no significant difference between them) than those obtained for sound dentin. Adhesive systems showed similar bond strength values. The percentage of premature failure was higher in the microbiological group, regardless of adhesive system. CONCLUSION Microbiological and pH-cycling methods are both suitable for simulating caries-affected dentin for bonding evaluations in primary teeth.

Do glass ionomer cements prevent caries lesions in margins of restorations in primary teeth?: A systematic review and meta-analysis

BACKGROUND Fluoride released from glass ionomer cements (GICs) is capable of preventing caries lesions. However, the preventive effect in margins of occlusal and occlusoproximal restorations have not been proved. The aim of this study was to evaluate the ability of GIC to prevent caries lesions in margins of occlusal and occlusoproximal restorations in primary teeth compared with that of other restorative materials. TYPES OF STUDIES REVIEWED The authors conducted a literature search in PubMed and MEDLINE to verify the clinical trials available on the outcome of caries lesions. The inclusion criteria were that the subject related to the scope of this systematic review, the study had a follow-up, and the study was not performed in specific groups. The authors performed all meta-analyses by considering the secondary caries rates for the restorations in clinical trials. RESULTS The search strategy identified 450 potentially relevant studies, and the authors included 8 of them in the review. The main reasons for exclusion were that the studies were not related to the scope of this review or were not longitudinal trials. The secondary caries rate of the occlusal restorations was not different among the restorative materials (odds ratio, 1.2; 95% confidence interval, 0.5-3.1). For occlusoproximal analysis, GIC was associated significantly with better ability to prevent caries lesions (odds ratio, 1.7; 95% confidence interval, 1.2-2.5). CONCLUSIONS AND PRACTICAL IMPLICATIONS Because new caries lesions in the margins of restorations are the main reason for failure and replacement of restorations in primary teeth, it is important to know whether there is a benefit in using GICs in both occlusal and occlusoproximal cavities.

Mechanical properties of high-viscosity glass ionomer cement and nanoparticle glass carbomer

Introduction. The lack of evidence regarding the best available material for restoring occlusal-proximal cavities in primary teeth leads to the development of new restorative material, with nanoparticles, in order to enhance mechanical properties, resulting in increased restoration longevity. Aim. To evaluate the Knoop hardness and bond strength of nanoparticles material glass carbomer cement (CAR) and high-viscosity glass ionomer cement (GIC) in sound and caries-affected dentin. Methods. Forty bovine incisors were selectedand assigned into four groups (n = 10): SGIC, sound dentin and GIC; SCAR, sound dentin and CAR; CGIC, caries-affected dentin andGIC; and CCAR, caries-affected dentin and CAR. All groups were submitted to microshear bond strength (MPa). Knoop hardness was also performed. Bond strength values were subjected to two-way ANOVA and Tukey test. Knoop hardness data were subjected to one-way ANOVA. Results. GIC presented higher Knoop hardness (p < 0.001) and bond strength (p = 0.027) than CAR. Also, both materials showed better performance in sound than in caries-affected substrates (p = 0.001). The interaction between factors was not statistically different (p = 0.494). Conclusion. Despite nanoparticles, CAR shows inferior performance as compared to GIC for the two properties tested in vitro. Moreover, sound dentin results in better bonding performance of both restorative materials evaluated.

Contact with fluoride-releasing restorative materials can arrest simulated approximal caries lesion

Previous studies have suggested that the presence of white-spot lesion is very probable when adjacent surface is affected by cavitated lesions. This study evaluated the potential of different fluoride-releasing restorative materials in arresting enamel white-spot lesions in approximal surface in contact with them, in vitro (I) and in situ (II). White-spot lesions were formed in 240 primary enamel specimens via pH-cycling. They were put in contact with cylindrical blocks of 6 materials (n = 20): composite resin, 2 high-viscous glass ionomer cements (HVGIC), resin-modified GIC, resin-modified nanoionomer, and polyacid-modified resin. In both studies I and II, these settings were designed to simulate the contact point between the restoration and simulated approximal lesion. For study I, they were subjected to a new pH-cycling cariogenic challenge for 7 or 14 days (n = 10). For study II, a randomized doubleblind in situ design was conducted in two phases (7/14 days) to promote cariogenic challenge. At the end of both studies, specimens were collected for mineral analysis by cross-sectional microhardness. Higher mineral loss was observed for lesions in contact with resin (p < 0.001). HVGICs were the most efficient in preventing mineral loss, whereas other materials presented an intermediate behavior. It is concluded that fluoride-releasing materials can moderately reduce white-spot lesions progression, and HVGIC can arrest enamel lesion in approximal surface in contact with them.

Caries lesion prevention and arrestment in approximal surfaces in contact with glass ionomer cement restorations - a systematic review and meta-analysis

BACKGROUND Studies have suggested that in the presence of approximal cavities, the approximal surface in contact with this one shows a higher risk in the development of caries lesions. AIM To evaluate the ability of dental materials to prevent and to arrest caries lesion in approximal surfaces in contact with occlusoproximal restorations. DESIGN Two independent reviewers performed a literature search in PubMed through November 2014. The inclusion criteria were: (1) subject related to the scope of this systematic review, (2) study with follow-up, (3) not performed in specific groups, (4) to have a comparison group. After selection by title and abstract, potentially eligible articles were read in full. Meta-analysis was carried out considering the outcome as caries lesion progression or arrestment. RESULTS The search strategy identified 772 potentially relevant studies, and 10 of them were included in the review (six laboratory studies and four longitudinal trials). For the longitudinal clinical trials, no difference was verified among the materials (OR = 0.680,95%CI:0.233-1.983). When a meta-analysis was performed for laboratory studies, GIC was significantly associated with better ability to arrest caries lesions (OR = 0.153,95%CI:0.060-0.391). CONCLUSIONS In laboratory studies, GIC shows better ability to arrest caries lesion in approximal adjacent surfaces, but this ability was not confirmed in longitudinal clinical trials.

Evaluation of the relationship between the cost and properties of glass ionomer cements indicated for atraumatic restorative treatment

The aim of this study was to evaluate microshear bond strength (μSBS), water sorption and solubility of glass ionomer cements (GIC) indicated for atraumatic restorative treatment (ART). Cylindrical specimens (6 x 2.4 mm) were used to test the sorption and solubility of each GIC (n = 5). The specimens were weighed before and after immersion in water and desiccation. For the μSBS test, 60 primary molars were ground to obtain flat surfaces from both enamel and dentin. The teeth were then assigned to the tested GIC (n = 10) groups, namely Fuji IX - FIX, Ketac Molar - KM and Maxxion R - MX. The exposed surfaces were pre-treated with GIC liquid. Polyethylene tubes were placed on the pre-treated surface and filled with one of the GIC. After 24 h, the specimens were submitted to the μSBS test. The failure mode was assessed using a stereomicroscope (400 x magnification). The powder to liquid ratio and cost of material were also determined (n = 3). The data were analyzed by ANOVA and Tukeys post hoc test. Linear regression was used to determine the relation between cost and the other variables. Overall, MX showed lower μSBS values (enamel: 3.93 ± 0.38; dentin: 5.04 ± 0.70) than FIX (enamel: 5.95 ± 0.85; dentin: 7.01 ± 1.06) and KM (enamel: 5.91 ± 0.78; dentin: 6.88 ± 1.35), as well as higher sorption and solubility. The regression analyses showed a significant and positive correlation between cost and μSBS in enamel (R2 = 0.62; p < 0.001) and dentin (R2 = 0.43; p < 0.001); and a negative correlation between cost and water sorption (R2 = 0.93; p < 0.001) and solubility (R2 = 0.79; p < 0.001). In conclusion, the materials indicated for ART exhibit distinct physical and mechanical properties; in addition, low-priced materials may interfere with GIC properties.

Laser for bone healing after oral surgery: systematic review

The purpose of this study is to perform a systematic review on the use of lasers in oral surgery for bone healing. Selection of articles was carried out by two evaluators in Pubmed and Web of Science databases for published articles and OpenGray for gray literature. Search strategy was developed based on the PICO Question “Does the use of lasers after oral surgery improve bone healing?”. Eligibility criteria were: being on laser; evaluate bone healing; involve oral surgery; do not be about implant, periodontics, orthodontics, osteonecrosis or radiotherapy, nor revisions, clinical cases, etc. Data were collected from each article in a structured spreadsheet and a descriptive analysis was performed. Risk assessment of bias of the articles was carried out through the tool elaborated by the Cochrane collaboration. A total of 827 potentially relevant references were identified. No articles were found in OpenGray. Eleven articles met the eligibility criteria and were included in the systematic review. Most of studies were in vivo and in jaw, being conducted with low-power lasers which were applied immediately after the surgical procedure of extraction. Neoformation and bone density were the outcomes of choice and there was a tendency of increase in bone density, neoformation, regeneration, mineralization, or bone condensation when laser was applied. Regarding the bias risk assessment, studies were not clear in reporting most of the parameters. Low-power laser therapy seems to reduce time of bone healing in oral surgery, although there are no defined protocols and the level of evidence is still considered weak.