Fragment reattachment or direct restoration? An in vitro study.

BACKGROUND/AIM: The fracture resistance of teeth subjected to fragment reattachment may improve when the technique is performed using intermediate materials. The aim of this study was to evaluate the influence of different bonding materials, including pre-heated composite resin, on the fracture resistance of teeth subjected to the reattachment technique compared with a direct composite resin restoration. MATERIALS AND METHODS: After simulating a tooth fracture, each specimen was reattached by using one of the following intermediate materials (n = 15): G0, negative control (sound teeth); G1, Z100; G2, pre-heated Z100; G3, Filtek Z350 XT; G4, pre-heated Filtek Z350 XT; G5, Filtek Z350 XT Flow; and G6, RelyX Veneer. In G7, direct class IV restorations were performed using Filtek Z350 XT composite resin. The fracture resistance was evaluated using a universal testing machine under a compressive load of 1 mm/min. One-way analysis of variance (ANOVA) and the post hoc Tukey test (5%) were conducted. RESULTS: G0 showed the highest fracture resistance, and this was statistically different from the other experimental groups (p < .05) except for G2 and G4, in which the fragments were bonded using pre-heated resins. A statistically significant difference was found between groups G1 and G6 (one-way ANOVA, p = .04). For G1 and G2, a significant difference was found between bonding with and without pre-heating (p < .05). This difference was not observed in G3 and G4 (p > .05). No statistically significant difference was found between the reattached and directly restored groups (t-test, p = .53). CONCLUSIONS: The tooth reattachment technique using pre-heated composite resin showed fracture resistance values similar to those of the sound tooth group. No difference was found between the fragment reattachment and direct composite resin techniques.

The impact of radiation caries in the quality of life of head and neck cancer patients.

PURPOSE: The objective of this multicentre study was to verify the relationship between the scores of quality of life (QoL) and the decayed, missing and filled teeth (DMFT) and radiation caries (RC) in patients treated with radiation therapy (RT) for head and neck cancer, and through this to determine if RC is capable of causing a significant decrease in the QoL. METHODS: One hundred patients were divided into 2 groups: patients with at least 1 year of RT completion who developed RC (study group, n = 50); and patients with at least 1 year of RT completion who did not develop RC (control group, n = 50). All patients answered the Brazilian-Portuguese version of the University of Washington quality of life (UW-QoL) questionnaire, which was divided into physical and social-emotional functioning domains and evaluated the DMFT index score. RESULTS: The mean score of QoL was 927.2 in the control group and 878.1 in the study group (P = 0.24). The mean score of DMFT was 30.5 in the study group and 20.7 in the control group (P = 0.001). The items recreation and saliva, which belong to the physical function domain, showed a statistically significant difference between the study and control groups (P = 0.031 and P = 0.047, respectively). Saliva was the item with the higher number of patient complaints in both groups. CONCLUSION: RC had a negative impact on the QoL of HNC patients.

Human pulp response to conventional and resin-modified glass ionomer cements applied in very deep cavities.

OBJECTIVES: This study assessed the human pulp response after adhesive restoration of cavities by indirect pulp capping with a conventional or a resin-modified glass ionomer cement. MATERIALS AND METHODS: Deep cavities prepared in 26 human premolars were lined with Riva Light Cure (Riva LC), Riva Self Cure (Riva SC), or Dycal, and then restored with composite resin. Four teeth were used as intact control. After time intervals of 7 or 30 days, the teeth were extracted, processed for histological evaluation of the pulp, and the remaining dentin thickness (RDT) between the cavity floor and the pulp was measured. RESULTS: At 7 days, a slight pulp inflammation associated with discrete tissue disorganization was observed in most of t the teeth lined with Riva LC and Riva SC. Moderate pulp inflammation occurred in one tooth lined with Riva LC. Bacteria were identified in one specimen of the same group that exhibited no pulp damage. At 30 days, slight pulp inflammation and discrete tissue disorganization persisted in two specimens treated with Riva LC, in which a thin layer of tertiary dentin was deposited. Mean RDTs ranged from 383.0 to 447.8 µm. CONCLUSIONS: Riva LC produced more damage to the pulp than Riva SC. However, the initial pulp damage decreased over time and after 30 days both GICs were labeled as biocompatible. CLINICAL RELEVANCE: In this study conducted with human teeth, the conventional and the resin-modified glass ionomer cements investigated were shown not to cause post-operative sensitivity or persistent pulp damage when applied as liners in very deep cavities, thereby indicating their biocompatibility.

Dental caries lesions in primary teeth without obvious cavitation: Treatment decision-making process.

BACKGROUND: Dental caries diagnosis and management have changed over time. AIM: To identify the treatment decision-making process performed by paediatric dentists, after caries detection using CAST instrument (Caries Assessment Spectrum and Treatment), for enamel (CAST 3) and non-cavitated dentin caries lesions (CAST 4) before and after analysing radiographic images. DESIGN: Seventy-four paediatric dentists were invited to participate. Twelve clinical cases were presented online, and treatment decisions before and after the analysis of bitewing radiographs were evaluated. RESULTS: Sixty-one specialists answered the questionnaire. The necessity for radiographs was significantly associated with the presence and depth of the caries lesion (P < 0.0001). CAST 3 lesions were preferentially monitored before and after the radiographic assessment. For CAST 4 lesions limited to the outer half of dentin, treatments indicated before and after radiographic analysis were sealant (33%) and restoration (40%). For the lesions in the inner half of dentin, restoration was the most cited before (45%) and after (84%) radiographs. The radiographic depth was the only significant independent variable when "change in the treatment option" was analysed by the regression model (P < 0.001). CONCLUSIONS: Enamel lesions were treated through less invasive treatments. Radiographs influenced the decision, especially for the lesions that involved the inner half of dentin.

Curcumin-mediated anti-microbial photodynamic therapy against Candida dubliniensis biofilms.

The purpose of this study was to evaluate the effectiveness of anti-microbial photodynamic therapy (aPDT) mediated by curcumin (Cur) associated with LED light against biofilms of Candida dubliniensis, and further, investigate cellular uptake and drug penetration through the biofilms under confocal laser scanning microscopy (CLSM). Four C. dubliniensis strains were tested: three clinical isolates from HIV-positive patients and one reference strain (CBS 7987). Biofilms were treated with three Cur concentrations (20.0, 30.0, and 40.0 µM). All samples were incubated in the dark for 20 min and exposed to a 5.28 J/cm2 of LED light fluence. Additional samples of each strain were treated either with Cur or LED light only. Control samples had neither Cur nor light. After aPDT, results were read using the XTT salt reduction method. The data were statistically analyzed by two-way ANOVA followed by Games-Howell post-hoc test (α = 0.05). Confocal laser scanning microscopy was used to verify both the uptake of Cur by yeast cells and its penetration through the biofilm. The results showed that aPDT promoted significant reduction on the metabolism of the biofilm-organized cells of C. dubliniensis. Further, while Cur was rapidly taken up by C. dubliniensis cells, a longer time interval was required to allow Cur penetration into biofilm cells. Based on these results, aPDT associating LED and Cur presents promising potential on fungal control of biofilms of C. dubliniensis.

Glass hybrid restorations as an alternative for restoring hypomineralized molars in the ART model.

BACKGROUND: This study aimed to evaluate the survival rate of glass hybrid restorations placed under the atraumatic restorative treatment (ART) technique in first permanent molars affected by molar incisor hypomineralization (MIH). METHODS: Sixty teeth with severe MIH associated to carious dentin lesions without pulp involvement were included. Treatments were performed by one trained dentist using the ART approach and restored with a glass hybrid restorative system (Equia Forte, GC®) on school premises. Treatments were evaluated after 6 and 12 months by an independent examiner using the modified ART criterion. Data analysis involved descriptive statistics and actuarial success analysis. RESULTS: The sample comprised 24 (54.54%) girls and 20 (45.45%) boys with a mean age of 10.55 (±1.25) years. In regard to the number of surfaces involved in the restorations, 29 (48.3%) comprised one surface and 31 (51.7%) two or more surfaces. Considering cavity extent, 25 (41%) presented dentin cavitation without cusp weakness, 23 (37.7%) with large dentin cavitation with cusp weakness and 13 (21.3%) with large dentin cavitation with the breakdown of one or more cusps. Only 4 teeth required local anesthesia. A success rate of 98.3% after 6 and 12 months was observed, as only one restoration failed. The only failure occurred in a restoration involving three or more sur-faces presenting the breakdown of all cusps. CONCLUSION: Restorations using a glass hybrid restorative system and performed in the field with the ART technique proved, after 12 months of evaluation, to be an effective approach to preserving first permanent molars affected by MIH. TRIAL REGISTRATION: REBEC-RBR-8drccq (17/06/15).

Caries Assessment Spectrum and Treatment (CAST): A Novel Epidemiological Instrument.

Caries detection is fundamental to understanding the oral health status of a population and is the basis for caries diagnosis for individual patients. Although different caries detection/diagnosis criteria are available, none of them include the total spectrum of dental caries (which ranges from a sound tooth to a tooth lost due to caries) other than the Caries Assessment Spectrum and Treatment (CAST) instrument. The CAST codes and descriptions were submitted to experienced epidemiologists from across the world for obtaining face and content validity. Its construct validity and reproducibility under field conditions were tested in child and adult populations, and showed a high level of agreement between examiners. Compared to what is usually reported in the literature, CAST provides more relevant information on caries prevalence, experience, and severity. CAST is straightforward and easy to use. A manual with valuable information about how to apply CAST and report its results has been published in order to facilitate communication among researchers, oral health planners, and medical professionals. Feedback from researchers indicates that CAST is considered an asset and that reporting results after using CAST is uncomplicated. More research about the effects of CAST in different cultures and age groups is required.

Do parents and children perceive molar-incisor hypomineralization as an oral health problem?

BACKGROUND: Very little is known about how patients perceive molar-incisor hypomineralization (MIH). AIM: The aim of this study was to identify whether parents and children perceive opacities associated with MIH as an oral health problem. DESIGN: A case-control study was designed in which 131 children diagnosed with MIH were matched by age, sex, and school to 131 children without MIH. The Child and Parent Questionnaire about Tooth Appearance was used to assess reports from parents, who were interviewed by telephone, and children, who were interviewed on school premises. The Spearman correlation and Wilcoxon and Fisher's exact tests were used to assess the data. RESULTS: For the first part of the questionnaire, children avoided smiling because of the appearance of their teeth, and mothers seemed to be distressed by the appearance of their children's teeth (P < 0.05). For the second part, children showed dissatisfaction with their 'tooth alignment' and 'tooth discoloration' compared with the controls, while mothers were not satisfied with their children's tooth discoloration in comparison with controls (P < 0.05). Children and mothers were concerned about tooth discoloration (P < 0.05). CONCLUSION: Poor agreement was found between the reports of children and their mothers, but both children and mothers in the MIH group perceived MIH opacities negatively in comparison with controls.

Antimicrobial photodynamic therapy against pathogenic bacterial suspensions and biofilms using chloro-aluminum phthalocyanine encapsulated in nanoemulsions.

Antimicrobial photodynamic therapy represents an alternative method of killing resistant pathogens. Efforts have been made to develop delivery systems for hydrophobic drugs to improve the photokilling. This study evaluated the photodynamic effect of chloro-aluminum phthalocyanine (ClAlPc) encapsulated in nanoemulsions (NE) on methicillin-susceptible and methicillin-resistant Staphylococcus aureus suspensions and biofilms. Suspensions and biofilms were treated with different delivery systems containing ClAlPc. After the pre-incubation period, the drug was washed-out and irradiation was performed with LED source (660 ± 3 nm). Negative control samples were not exposed to ClAlPc or light. For the suspensions, colonies were counted (colony-forming units per milliliter (CFU/mL)). The metabolic activity of S. aureus suspensions and biofilms were evaluated by the XTT assay. The efficiency was dependent on the delivery system, superficial load and light dose. Cationic NE-ClAlPc and free-ClAlPc caused photokilling of the both strains of S. aureus. For biofilms, cationic NE-ClAlPc reduced cell metabolism by 80 and 73% of susceptible and resistant strains, respectively. Although anionic NE-ClAlPc caused a significant CFU/ml reduction for MSSA and MRSA, it was not capable of reducing MRSA biofilm metabolism. This therapy may represent an alternative treatment for eradicating resistant strains.

Responses of dental pulp cells to a less invasive bleaching technique applied to adhesive-restored teeth.

PURPOSE: To assess the cytotoxicity of 35% hydrogen peroxide (HP) bleaching gel applied for 15 min to sound or restored teeth with two-step self-etching adhesive systems and composite resin. MATERIALS AND METHODS: Sound and restored enamel/dentin disks were stored in water for 24 h or 6 months + thermocycling. The disks were adapted to artificial pulp chambers and placed in compartments containing culture medium. Immediately after bleaching, the culture medium in contact with dentin was applied for 1 h to previously cultured odontoblast-like MDPC-23 cells. Thereafter, cell viability (MTT assay) and morphology (SEM) were assessed. Data were analyzed by two-way ANOVA and Tukey's test (a = 5%). RESULTS: In comparison to the negative control group (no treatment), no significant cell viability reduction occurred in those groups in which sound teeth were bleached. However, a significant decrease in cell viability was observed in the adhesive-restored bleached groups compared to negative control. No significant difference among bleached groups was observed with respect to the presence of restoration and storage time. CONCLUSION: The application of 35% HP bleaching gel to sound teeth for 15 min does not cause toxic effects in pulp cells. When this bleaching protocol was performed in adhesive-restored teeth, a significant toxic effect occurred.

Effect of low-level laser therapy on odontoblast-like cells exposed to bleaching agent.

The aim of the present study was to evaluate the effect of low-level laser therapy (LLLT) on odontoblast-like MDPC-23 cells exposed to carbamide peroxide (CP 0.01%-2.21 µg/mL of H2O2). The cells were seeded in sterile 24-well plates for 72 h. Eight groups were established according to the exposure or not to the bleaching agents and the laser energy doses tested (0, 4, 10, and 15 J/cm(2)). After exposing the cells to 0.01% CP for 1 h, this bleaching solution was replaced by fresh culture medium. The cells were then irradiated (three sections) with a near-infrared diode laser (InGaAsP-780 ± 3 nm, 40 mW), with intervals of 24 h. The 0.01% CP solution caused statistically significant reductions in cell metabolism and alkaline phosphate (ALP) activity when compared with those of the groups not exposed to the bleaching agent. The LLLT did not modulate cell metabolism; however, the dose of 4 J/cm(2) increased the ALP activity. It was concluded that 0.01% CP reduces the MDPC-23 cell metabolism and ALP activity. The LLLT in the parameters tested did not influence the cell metabolism of the cultured cells; nevertheless, the laser dose of 4 J/cm(2) increases the ALP activity in groups both with and without exposure to the bleaching agent.

Effect of preheating on the viscosity of composite resins.

Aim: To determine the effects of time and temperature on the viscosity of preheated composite resins. Materials and Methods: Eleven composite resins were heated to 60°C, and temperature analyses were performed at intervals of 1 min until they had cooled to 25°C. The permanent oscillatory shear test was performed at 25°C, 35°C, 50°C, and 60°C for three composite resins under a shear rate of 1s-1. One- and two-way analysis of variance were used for the analysis (α = 0.05). Results: There was no significant interaction between the composite resin and time (P = 0.9304), and only the main effect time was significantly different (P < 0.0001). A difference was observed between T0 and T6 (P < 0.001), but not after T7. The increase in temperature resulted in a viscosity reduction (P < 0.05). At 25°C, Beautifil II presented higher viscosity. Palfique LX5 showed a significant viscosity reduction with increasing temperature compared with the others (P < 0.05). For Beautifil II and Z100, there was no difference at temperatures of 50°C and 60°C, while for Palfique LX5, no statistical difference was observed at 35°C, 50°C, and 60°C. Conclusions: Ten minutes of preheating were sufficient to reach a temperature of 60°C, reducing viscosity by at least 84%. However, 5 min after removal, the composite resin cooled to room temperature. Clinical Significance: Preheating composite resin has potential benefits. To determine how this approach will work in clinical practice, it is important to define the effects of time and temperature in the protocol of this technique and understand its limitations.

Phototoxic effect of curcumin on methicillin-resistant Staphylococcus aureus and L929 fibroblasts.

Photodynamic therapy has been investigated as an alternative method of killing pathogens in response to the multiantibiotic resistance problem. This study evaluated the photodynamic effect of curcumin on methicillin-resistant Staphylococcus aureus (MRSA) compared to susceptible S. aureus (MSSA) and L929 fibroblasts. Suspensions of MSSA and MRSA were treated with different concentrations of curcumin and exposed to light-emitting diode (LED). Serial dilutions were obtained from each sample, and colony counts were quantified. For fibroblasts, the cell viability subsequent to the curcumin-mediated photodynamic therapy was evaluated using the MTT assay and morphological changes were assessed by SEM analysis. Curcumin concentrations ranging from 5.0 to 20.0 µM in combination with any tested LED fluences resulted in photokilling of MSSA. However, only the 20.0 µM concentration in combination with highest fluence resulted in photokilling of MRSA. This combination also promoted an 80% reduction in fibroblast cell metabolism and morphological changes were present, indicating that cell membrane was the main target of this phototherapy. The combination of curcumin with LED light caused photokilling of both S. aureus strains and may represent an alternative treatment for eradicating MRSA, responsible for significantly higher morbidity and mortality and increased healthcare costs in institutions and hospitals.

Efficacy and cytotoxicity of a bleaching gel after short application times on dental enamel.

OBJECTIVES: This study aimed to evaluate and correlate the efficacy and cytotoxicity of a 35 % hydrogen peroxide (HP) bleaching gel after different application times on dental enamel. MATERIALS AND METHODS: Enamel/dentin disks in artificial pulp chambers were placed in wells containing culture medium. The following groups were formed: G1, control (no bleaching); G2 and G3, three or one 15-min bleaching applications, respectively; and G4 and G5, three or one 5-min bleaching applications, respectively. Extracts (culture medium with bleaching gel components) were applied for 60 min on cultured odontoblast-like MDPC-23 cells. Cell metabolism (methyl tetrazolium assay) (Kruskal-Wallis/Mann-Whitney; α = 5 %) and cell morphology (scanning electron microscopy) were analyzed immediately after the bleaching procedures and the trans-enamel and trans-dentinal HP diffusion quantified (one-way analysis of variance/Tukey's test; α = 5 %). The alkaline phosphatase (ALP) activity was evaluated 24 h after the contact time of the extracts with the cells (Kruskal-Wallis/Mann-Whitney; α = 5 %). Tooth color was analyzed before and 24 h after bleaching using a spectrophotometer according to the Commission Internationale de l'Eclairage L*a*b* system (Kruskal-Wallis/Mann-Whitney; α = 0.05). RESULTS: Significant difference (p < 0.05) in cell metabolism occurred only between G1 (control, 100 %) and G2 (60.6 %). A significant decrease (p < 0.05) in ALP activity was observed between G2, G3, and G4 in comparison with G1. Alterations on cell morphology were observed in all bleached groups. The highest values of HP diffusion and color alterations were observed for G2, with significant difference among all experimental groups (p < 0.05). G3 and G4 presented intermediate color change and HP diffusion values with no statistically significant differences between them (p > 0.05). The lowest amount of HP diffusion was observed in G5 (p < 0.05), which also exhibited no significant color alteration compared to the control group (p > 0.05). CONCLUSIONS: HP diffusion through dental tissues and its cytotoxic effects were proportional to the contact time of the bleaching gel with enamel. However, shorter bleaching times reduced bleaching efficacy. CLINICAL RELEVANCE: Shortening the in-office tooth bleaching time could be an alternative to minimize the cytotoxic effects of this clinical procedure to pulp tissue. However, the reduced time of bleaching agent application on enamel may not provide adequate esthetic outcome.

Low toxic effects of a whitening strip to cultured pulp cells.

PURPOSE: To assess the trans-enamel and trans-dentin toxicity of a 10% hydrogen peroxide (HP) whitening strip to odontoblast-like cells (MDPC-23). METHODS: Enamel surfaces of enamel/dentin discs adapted to artificial pulp chambers were subjected to two 30-minute whitening strip applications to obtain indirect extracts (DMEM + bleaching components that diffused across enamel and dentin). The extracts were applied for 1 hour to the cells for 1 or 5 days. A bleaching gel with 35% HP was used as the positive control. Cell viability (MTT assay) and morphology (SEM) as well as the quantity of HP in the extracts were assessed. RESULTS: Discrete cell viability reduction (21.9%) associated with slight alterations in cell morphology occurred after application of the extracts for 5 days to the MDPC-23 cells (Tukey's test; P < 0.05). Lower enamel/dentin diffusion of HP was observed after the use of the whitening strip compared with the bleaching gel (Mann-Whitney; P < 0.05).

Toxic effects of daily applications of 10% carbamide peroxide on odontoblast-like MDPC-23 cells.

BACKGROUND: bleaching has been widely studied, mainly due to the possible undesirable effects that can be caused by this esthetic procedure. The cytotoxicity of the bleaching agents and its components to pulp cells has been demonstrated in several researches. The aim of this study was to evaluate the toxic effects of successive applications of 10% carbamide peroxide (CP) gel on odontoblast-like cells. MATERIALS AND METHODS: Enamel-dentin discs obtained from bovine incisors were adapted to artificial pulp chambers (APCs). The groups were formed as follows: G1: Without treatment (control group); G2: 10% carbamide peroxide, CP (five applications/one per day); G3: 10% CP (one unique application); and G4: 35% hydrogen peroxide, HP (three applications of 15 min each). After treatment, cell metabolism (MTT), alkaline phosphatase (ALP) activity and plasma membrane damage (flow cytometry) were analyzed. RESULTS: Reductions in cell metabolism and alkaline phosphatase activity along with severe damage of the cytoplasmic membrane were noted in G2. In G3, no damage was observed, compared to the control group. Intermediary values of toxicity were obtained after 35% HP application. CONCLUSION: It can be concluded that one application of 10% CP did not cause toxic effects in odontoblast-like cells, but the successive application of this product promoted severe cytotoxic effects. The daily application of the bleaching agents, such as used in the at-home bleaching technique, can increase the damages caused by this treatment to the dental pulp cells.

Subjective versus objective, polymer bur-based selective carious tissue removal: 2-year randomized clinical trial.

OBJECTIVES: We aimed to compare subjective (S) selective carious tissue removal using hand instruments versus objective (O) removal using a self-limiting polymer bur in a single-blind cluster-randomized controlled superiority trial. METHODS: 115 children (aged 7-8 years) with ≥1 vital primary molar with a deep dentin lesion (>1/2 dentin depth) were included and randomized (60 S/55 O); all eligible molars in a child were treated identically (91 S/86 O). Cavities were prepared and carious tissue on pulpal walls selectively removed using hand instruments (S) or a self-limiting polymer bur (Polybur P1, Komet), followed by restoration using a glass hybrid material (Equia Forte, GC). Treatment time and satisfaction data have been reported in a 1-year-interim report. We here report on 2 year survival (tooth retained with or without further retreatments being needed, or tooth exfoliated), analyzed using multi-level Cox-regression analysis, as well as success (ART criteria 0/1, no pulpal complications, no re-intervention needed, or tooth extraction). RESULTS: 71 restorations in S and 65 in O were examined after a mean (SD, range) of 22 (11; 3-31) months, of which 50 S and 48 O restorations were successful and 70 S and 65 O survived. The majority of failures were restorative, not pulpal, and distribution of ART codes was not significant different between groups. Risk of failure was not significantly associated with the removal protocol (HR; 95 % CI: 0.95; 0.51-1.78), and also not age, sex or dental arch, while single surfaced restorations showed significantly lower hazard (0.14; 0.06-0.37). CONCLUSION: There was no significant difference in success or survival between objective and subjective carious tissue removal. CLINICAL SIGNIFICANCE: In primary teeth, subjective selective excavation had no disadvantage compared with objective excavation, which required a separate instrument (polymer-based bur) for carious tissue removal. Polymer-based burs may be particularly useful when standardized excavation is needed.

Toxicity of photodynamic therapy with LED associated to Photogem®: an in vivo study.

The aims of this study were to evaluate the effects of Photogem®-mediated photosensitization on rat palatal mucosa and the biodistribution of the photosensitizer in this tissue. A solution of Photogem® (500 or 1000 mg/l) was applied to the palatal mucosa for 30 min and the exposure time to blue LED (460 nm) was 20 min (144 J/cm(2)). At 0, 1, 3, and 7 days, palatal mucosa was photographed for macroscopic analysis. After killing, the palate was removed for microscopic analysis. Thermal mapping evaluated temperature change in the tissue during irradiation. All experimental groups revealed intact mucosa in the macroscopic analysis. Tissue alterations were observed microscopically for only four out of 80 animals subjected to PDT. Fluorescence emitted by Photogem® was identified and was limited to the epithelial layer. A temperature increase from 35 to 41°C was recorded. Photogem®- mediated PDT was not toxic to the rat palatal mucosa.

Pro-inflammatory mediators expression by pulp cells following tooth whitening on restored enamel surface.

This paper aimed to assess the influence of adhesive restoration interface on the diffusion of hydrogen peroxide (H2O2), indirect toxicity, and pro-inflammatory mediators expression by odontoblast-like cells, after in-office tooth whitening. Dental cavities prepared in bovine enamel/dentin discs were adhesively restored and subjected or not to hydrolytic degradation (HD). A whitening gel with 35% H2O2 (WG) was applied for 45 min onto restored and non-restored specimens adapted to artificial pulp chambers giving rise to the groups: SD- intact discs (control); SD/HP- whitened intact discs; RT/HP- restored and whitened discs; and RT/HD/HP- restored and whitened discs subjected to HD. The extracts (culture medium + WG components diffused through enamel/dentin/restoration interface) were collected and applied to odontoblast-like MDPC-23 cells. The study evaluated the amount of H2O2 in the extracts, as well as the cell viability (CV), cell morphology (CM), and gene expression of inflammatory mediators (TNF-α and COX-2) by the pulp cells exposed to the extracts (ANOVA and Tukey tests; 5% significance). All whitened groups presented lower CV than SD (control; p<0.05). The highest CV reduction and gene expression of TNF-α and COX-2 was observed in the RT/HD/HP group in comparison with SD/HP and RT/HP (control; p<0.05). CM alterations occurred in all whitened groups. The intensity of these cell side effects was directly related with the amount of H2O2 in the extracts. We concluded that adhesive restoration of dental cavity increases the H2O2 diffusion after in-office whitening, enhancing the indirect toxicity of this therapy and trigger pro-inflammatory overexpression by MDPC-23 cells.

Is there an association between dental caries, fluorosis, and molar-incisor hypomineralization?

OBJECTIVE: This cross-sectional study aimed to determine the prevalence of dental caries, dental fluorosis, and molar-incisor hypomineralization, and their associations in a group of Brazilian schoolchildren. METHODOLOGY: Adolescents (n=411) were evaluated by two calibrated examiners for dental caries (DC), dental fluorosis (DF), and molar-incisor hypomineralization (MIH) using the CAST (Caries Assessment Spectrum and Treatment) instrument, Thylstrup and Fejerskov (TF) index, and MIH Severity Scoring System (MIH-SSS), respectively. Descriptive statistics, chi-square tests, and logistic regression were used for statistical analysis. RESULTS: The sample comprised 42.75% boys and 57.25% girls. The prevalence of DC in permanent dentition was 94.75%, of which 29% were represented by dentin lesions. For DF, a prevalence of 40.75% was observed, with 69.32% mild, 12.88% moderate, and 17.79% severe. A positive association between the source of water and fluorosis was detected (p=0.01). The prevalence of MIH was 18%. Thirty adolescents (41.7%) presented with severe MIH. No association was found between DF or MIH and dentin DC or between MIH and DF at the individual level. However, a significant negative relationship was detected between DF and dentin carious lesions ( p <0.005) and DF and MIH ( p <0.00001) at the tooth level, whereas a positive association was observed between MIH and dentin carious lesions ( p <0.00001). A positive association was also observed between the severity of both conditions ( p <0.00001). Mild DF was the most prevalent problem observed. Cases of teeth with mild MIH were the most predominant in MIH-affected teeth. CONCLUSIONS: No association was observed among the dentin carious lesions, MIH, and DF at the participant level. However, a positive association between MIH and dentin carious lesions was found at the tooth level, whereas MIH, DF, and DF and dentin carious lesions showed a negative relationship.