Traumatic dental injuries and molar incisor hypomineralization: a cross-sectional study of schoolchildren from southern Brazil.

PURPOSE: To describe the prevalence and the variables associated with TDIs in schoolchildren aged 8 to 14 years in Estância Velha city in southern Brazil, placing emphasis on molar incisor hypomineralization. METHODS: Students enrolled in public schools of a medium-sized city in the southern Brazil were selected using cluster random sampling. Clinical examinations assessed molar incisor hypomineralization-MIH (European Academy of Pediatric Dentistry criteria), dental caries (DMFT index), and TDIs (O'Brien's criteria). Socioeconomic and demographic variables were assessed using a standardized questionnaire. Prevalence ratios were estimated using Poisson regression (p < 0.05). RESULTS: 513 students (54.8% female), with a mean age of 11.6 (± 1.9) years, participated in the study. The prevalence of TDIs was 11.3%, with enamel fracture representing 90.4%. The high prevalence of traumatic dental injuries was associated with MIH (PR: 2.22 CI: 1.27; 3.87; p < 0.01) and overjet > 3 mm (PR: 2.03 CI 1.19; 3.45; p < 0.01). CONCLUSION: The sample of schoolchildren from southern Brazil had a low prevalence of traumatic dental injuries. Molar incisor hypomineralization and increased overjet were associated with the higher prevalence of traumatic dental injuries.

Root canal filling materials for endodontic treatment of necrotic primary teeth: a network meta-analysis.

PURPOSE: To investigate the effect of different root canal filling materials on the change of failure of the endodontic treatment of necrotic primary teeth. METHODS: A literature search was carried out in PubMed/MEDLINE, CENTRAL, Scopus databases, and grey literature up to July 2022 selecting randomised clinical trials related to research question. Two reviewers independently selected the studies, extracted the data, and assessed the bias risk. Root canal filling materials were grouped according to the main component [iodoform (IOD), calcium hydroxide (CAOH), zinc oxide (ZO) or mix (IOD plus CAOH plus ZO) pastes]. Pairwise and network meta-analyses using the mixed treatment comparisons method were performed to compare the number of events (failure) among treatments. Odds ratio and 95% confidence intervals (CI) for calculated. Post-probabilities among treatments were also calculated and interpreted. RESULTS: From 1186 potentially relevant studies, 17 were selected for full-text analysis, and 7 were included in the meta-analysis, totalizing 263 teeth. In the direct evidence, ZO pastes resulted in a higher chance of failure than IOD pastes (OR 7.07 95% CI 1.02, 62.59). In the indirect evidence, there was no difference between the materials. The IOD pastes presented a high probability (81%) of being the treatment associated to lowest number of failures among all treatments. The CAOH pastes presented the highest probability of being the worst option. Studies showed high bias risk. CONCLUSION: There is currently no scientific evidence of the superiority of any one root canal filling material for endodontic treatment of necrotic primary teeth.

Does silver diammine fluoride concentration influence on bonding to carious dentinal lesions in primary teeth?

PURPOSE: This in vitro study evaluated the microshear bond strength (µSBS) of a universal adhesive after silver diammine fluoride (SDF) application at different concentrations on carious dentinal lesions in primary teeth. METHODS: Flat dentin carious-induced surfaces from 40 primary molars were randomly assigned to four experimental groups: without SDF treatment (control), 12% SDF, 30% SDF, or 38% SDF application. After 14 days of storage in artificial saliva at 37 °C, a universal adhesive system (Scotchbond Universal, 3 M ESPE) was applied in the etch-and-rinse mode and resin composite cylinders were built (0.72 mm2). After 24 h of water storage, the µSBS test was performed and the failure mode was determined. Data were analysed using one-way ANOVA and Tukey's post hoc tests (α = 0.05). RESULTS: The application of 38% SDF resulted in higher µSBS mean than control and use of 12% SDF (p = 0.006). No significant differences were observed among control, 12% SDF, and 30% SDF. All specimens tested showed adhesive/mixed failure. CONCLUSION: The use of SDF does not jeopardise the bonding of a universal adhesive applied in the etch-and-rinse mode to carious dentinal lesions in primary teeth, irrespective of the product concentration.

Zinc oxide eugenol paste jeopardises the adhesive bonding to primary dentine.

AIM: This was to evaluate the influence of root canal filling pastes on microshear bond strength (µSBS) of an adhesive system to primary dentine. METHODS: Human (32) primary molars were randomly assigned into four experimental groups (n = 8): zinc oxide eugenol paste (ZOE); iodoform paste (Guedes-Pinto paste); calcium hydroxide paste thickened with zinc oxide; and no filling paste (control). Flat dentine surfaces were covered with a 1 mm-thick layer of the pastes for 15 min at 37 °C. The pastes were mechanically removed from dentine surfaces, followed by rinsing and drying. After adhesive application (Adper Single Bond 2, 3M ESPE), starch tubes were placed over pre-treated dentine and filled with composite resin (Z250, 3M ESPE). The µSBS test was performed after 24 h of water storage at 37 °C. The failure mode was evaluated using a stereomicroscope. The µSBS values (MPa) were analysed with one-way ANOVA and Tukey post-hoc tests (α = 0.05). RESULTS: The lowest µSBS values were achieved when ZOE was used. No difference was found among other filling pastes compared with control group. All specimens showed adhesive/mixed failures. CONCLUSIONS: Zinc oxide eugenol paste negatively influenced the bond strength of adhesive systems to primary dentine. Iodoform-based Guedes-Pinto paste and calcium hydroxide paste thickened with zinc oxide did not influence the microshear bond strength values.

Degradation of Multimode Adhesive System Bond Strength to Artificial Caries-Affected Dentin Due to Water Storage.

The purpose of this study was to evaluate the influence of water storage on bond strength of multimode adhesive systems to artificially induced caries-affected dentin. One hundred twelve sound bovine incisors were randomly assigned to 16 groups (n=7) according to the dentin condition (sound; SND, artificially induced caries-affected dentin; CAD, cariogenic challenge by pH cycling for 14 days); the adhesive system (SU, Scotchbond Universal Adhesive; AB, All-Bond Universal; PB, Prime & Bond Elect; SB, Adper Single Bond 2; and CS, Clearfil SE Bond), and the etching strategy (etch-and-rinse and self-etch). All adhesive systems were applied under manufacturer's instructions to flat dentin surfaces, and a composite block was built up on each dentin surface. After 24 hours of water storage, the specimens were sectioned into stick-shaped specimens (0.8 mm2) and submitted to a microtensile test immediately (24 hours) or after six months of water storage. Bond strength data (MPa) were analyzed using three-way repeated-measures analysis of variance and post hoc Tukey test (α=5%), considering each substrate separately (SND and CAD). The etching strategy did not influence the bond strength of multimode adhesives, irrespective of the dentin condition. Water storage only reduced significantly the bond strength to CAD. The degradation of bond strength due to water storage was more pronounced in CAD, regardless of the etching strategy.

Degradation of resin-dentine bond of different adhesive systems to primary and permanent dentine.

AIM: To evaluate the water storage degradation of resin-dentine bonds of different adhesive systems to primary and permanent human dentine. METHODS: Flat occlusal human dentine surfaces of 15 primary molars and 15 permanent molars were randomly assigned according to adhesive systems: Adper Single Bond 2; Clearfil SE Bond and One Up Bond F Plus. After bonding procedures, the adhesives were applied according to the manufacturers' instructions and composite resin blocks were built. Restored teeth were sectioned rendering rectangular sticks (RS) (0.4 mm2). The RS were submitted to microtensile bond strength (µTBS) test according to the water storage time: 24 h, 1-year, and 2-years. Mean µTBS values were analysed by three-way analysis of variance (mixed design) and Tukey post hoc test (α = 0.05). The failure mode was analysed at 400× magnification. RESULTS: All three factors isolated showed significant influences on µTBS, as did the cross-product interactions between material vs. storage time (p = 0.01) and substrate vs. storage time (p = 0.002). Bond strength means to primary dentine were lower than to permanent dentine (34.7 ± 10.1 and 45.8 ± 12.9 mPa, respectively) after 2-years of water storage. The one-step self-etch adhesive (One Up Bond F Plus) showed less stable bond strength after 2-years of water storage. CONCLUSION: The resin-dentine bond of primary teeth was more prone to degradation over time compared to permanent dentine.

Bovine tooth is a substitute for human tooth on bond strength studies: A systematic review and meta-analysis of in vitro studies.

OBJECTIVES: This study aimed to systematically review the literature to compare the bond strength values achieved from human and bovine teeth of in vitro studies. DATA AND SOURCE: The PubMed/MEDLINE, ISI Web of Science and Scopus electronic databases were searched to select laboratorial studies that evaluated adhesive systems bond strength to human and bovine teeth. No publication year or language restriction was considered. STUDY SELECTION: From 1,285 potentially eligible studies, 15 were selected for full-text analysis, 11 were included in the systematic review and 9 in the meta-analysis. Two authors independently selected the studies, extracted the data and assessed the risk of bias. Mean differences were obtained by comparing bond strength values between human and bovine teeth (overall analysis), and considering enamel and dentin separately (subgroups analysis). Statistical analysis was performed using RevMan5.1, with random effects model, at a significance level of p=0.05. RESULTS: No significant difference was found between human and bovine teeth (p=0.35), either for enamel (p=0.07) or for dentin (p=0.93) substrates. Low to moderate heterogeneity was found on the meta-analysis. All included studies in the systematic review scored between medium and high risk of bias. CONCLUSIONS: Bovine teeth can be a reliable substitute for human ones on bond strength studies of adhesive systems to both enamel and dentin substrates.

Repairing ditched amalgam restorations is less time and tooth structure-consuming than replacement.

AIM: To evaluate the dental structure loss associated with procedures of replacement or maintenance for ditched amalgam restorations in primary molars and the time required to perform each treatment. METHODS: Ditched amalgam restorations (n = 40) were submitted to four different strategies: polishing group-polishing and finishing of restorations; amalgam group-replacement of ditched amalgam restorations with new amalgam restorations; resin group-replacement of amalgam restorations with resin composite restorations; flowable resin group-filling the ditch with a flowable resin composite. The teeth were analysed with a stereomicroscope and the areas pre- and post-treatment were determined by image analysis software to evaluate structural loss. The time required to perform each treatment was recorded in seconds. STATISTICS: Student's t test was used to compare areas pre- and post-treatments. ANOVA and Student-Newman-Keuls tests (p < 0.05) were used to compare differences among groups and the time to perform each procedure. RESULTS: Dental structure loss was observed in resin and amalgam groups. Replacing the restorations with amalgam took more time, while polishing and applying flowable resin composite consumed less than half of the time compared with amalgam and resin groups. CONCLUSION: Maintenance of ditched amalgam restorations by polishing and sealing preserves dental structure and involves less time compared with that for replacement of restorations.

Effect of air abrasion and polishing on primary molar fissures.

AIM: To evaluate the effect of air abrasion and polishing on primary molar fissures under light microscopy. METHODS: 15 exfoliated primary second molars were longitudinally sectioned and photographed under a stereomicroscope (40×; baseline evaluation). Sections were then randomly allocated into one of the two groups (n = 15) and treated by either air abrasion (aluminium oxide jet) or air polishing (sodium bicarbonate jet) for 30 s. After treatment, sections were washed with an air/water spray, dried with absorbent paper, and photographed as previously described (final evaluation). Baseline and final morphology were compared by two blinded examiners who evaluated changes in the width and depth of fissures. STATISTICS: The percentage of changed fissures was analysed, and the two treatments were compared using the Mann-Whitney test (α = 0.01). RESULTS: Both air systems resulted in fissure changes in most (93.3 %) of the sections. No significant differences in fissure width changes were found between treatments, but when changes in fissure depth were evaluated, air polishing was found to be less damaging than air abrasion (p < 0.01). CONCLUSION: Air abrasion and polishing cause changes to the anatomical configuration of occlusal fissures of primary molars.

Comparison of validation methods for the diagnosis of occlusal caries in primary molars.

AIM: To evaluate the reproducibility of 7 validation methods used for caries diagnosis in primary teeth. METHODS: Seventy-two occlusal sites were selected on 40 primary molars. The sites were evaluated independently by 3 experienced examiners using validation methods that involved direct assessment, i.e. by using a (1) magnifying glass (8×) and (2) stereomicroscope (35×), or indirect assessment i.e. by using (3) photographs, (4) slide projections of photographs, (5) stereomicroscope (35×) photographs, (6) stereomicroscope (35×) slide projections, and (7) projections of polarised light microscope slides. Cohen's kappa coefficients were calculated and subjected to the Kruskal-Wallis test at a significance level of 5%. RESULTS: The mean inter-examiner kappa values for the validation methods were 0.31-0.51. There were statistically significant differences (p<0.05) between methods 1 and 3, 1 and 4, 2 and 4, 4 and 5, 4 and 6, and 4 and 7. Moderate agreement was observed for all methods except methods 1 and 4, for which the agreement was fair. CONCLUSIONS: The inter-examiner agreement for all validation methods for caries diagnosis was moderate, except for the method based on indirect assessment by slide projection, which showed low agreement.