Dental Research Journal
Volume:16 Issue: 4, Jul-Aug 2019

Fixed orthodontic appliances can release metal ions such as nickel, chromium, and zinc into saliva and blood, which can cause contact dermatitis, hypersensitivity, and cytotoxicity. This study was undertaken to assess the release of nickel, chromium, and zinc in saliva and serum of patients undergoing fixed orthodontic treatment. This in vivo study was conducted on 80 participants with an age range of 15–40 years. Thirty were included as controls and 50 participants were treated with fixed orthodontic appliances. Saliva and blood samples were collected at five different periods, before insertion of fixed orthodontic appliance and at 1 week, 3 months, 1 year, and 1.5 years after insertion of appliance, respectively. The metal ion content in the samples were analyzed by atomic absorption spectrophotometry. Mean levels of nickel, chromium, and zinc in saliva and serum were compared
between groups using independent sample t‑test and before and after results using paired t‑test. P < 0.05 was considered as statistically significant. At the end of 1.5 years, the mean salivary levels of nickel, chromium, and zinc in controls were 5.02 ppb, 1.27 ppb, and 10.24 ppb, respectively, as compared to 67 ppb, 30.8 ppb, and 164.7 ppb at the end of 1.5 years. This was statistically significant with P < 0.001. A significant increase in the metal ion levels were seen in participants with before and after insertion of appliance (P < 0.001). Orthodontic appliances do release considerable amounts of metal ions such as nickel, chromium, and zinc in saliva and serum. However, it was within permissible levels and did not reach toxic levels.

Sealing ability is one of the most important features of endodontic sealers. The main goal of the present study was to compare sealing ability of mineral trioxide aggregate (MTA)‑propylene glycol (PG) with two commonly used resin‑based and MTA‑based sealers. In This in vitro study Seventy extracted single‑root teeth were used. Canal preparation was carried out using hand and RaCe rotary files. Ten teeth were used as control. The root canals in positive and negative control groups were left empty. Remaining 60 teeth were randomly divided into following four groups (n = 15): In Group 1, the canals were dried using paper cones and obturated using MTA‑PG sealer. In Group 2, saline was removed from canal using a syring, but paper cones were not used. Obturation was done using MTA‑PG sealer. In Groups 3 and 4, the canals were dried using paper cones and obturated with AH26 and MTA Fillapex, respectively. Two‑chamber method was used to evaluate bacterial leakage using Enterococcus faecalis (ATCC 29212). Turbidity of the lower chambers was checked every day during 90 days. Chi‑square, Kaplan–Meier analysis, and logrank tests were used to compare groups regarding leaked samples at the end of the study. The level of significance was set at 0.05. There was no significant difference among groups regarding rate of leakage throughout the study. However, at the end of the study, the groups were statistically different regarding leaked samples (P = 0.034). MTA Fillapex and MTA‑PG in dry canal showed the most and least leaked samples at the end of the study, respectively (P < 0.05). MTA mixed with PG has superior sealing ability than MTA Fillapex.

The early diagnosis of dental caries is very crucial to prevent tooth loss, which leads to serious consequences in preschool children. The aim of this study is to compare the diagnostic outcome by the World Health Organization (WHO) and WHO and early carious lesions (ECLs) (i.e., WHO + ECL) criteria for assessing early childhood caries (ECC) in preschool children. A cross‑sectional, comparative study was conducted among 3–5 year old children (n = 358). Clinical examination was conducted using WHO and WHO + ECL criteria. The data were assessed using paired “t” test. P < 0.05 was considered as statistically significant. There was statistically significant difference between the mean decayed, missing, or filled teeth recorded by the WHO + ECL and WHO (P < 0.05) method. It was concluded that WHO + ECL criteria were significant and more precise in assessing the presence of ECL in preschool children.

New tools have been introduced for tooth inclination measurement and assessment of its changes over time. This study aimed to measure the change in inclination of teeth after the periods of 2 and 4 years in adolescents with normal occlusion using three‑dimensional (3D) software. This retrospective longitudinal study was conducted on 54 pairs of dental casts of 24 adolescents between 9 and 13 years of age with normal occlusion. The inclination of teeth was determined by 3D measurements using OrthoAid software. After scanning the casts via stereophotogrammetric scanner, the mean and standard deviation of inclination of teeth were calculated at three time points. Change in these values was calculated after 2 and 4 years. The effect of sex, duration of follow‑up, and the jaw (maxilla/mandible) on change of inclination was analyzed using the Mann–Whitney and Wilcoxon tests. P < 0.05 was considered statistically significant. Incisor teeth torque was positive in the maxilla (9.72 ± 8) and mandible (4.22 ± 6.09), but it was negative for the canine (–7.73 ± 6.3 for maxilla and –9.9 ± 5.22 for mandible), premolar (–10.35 ± 6.84 for maxilla and –26.51 ± 9.94 for mandible), and molar teeth (–13.23 ± 6.22 for maxilla and –39.78 ± 9.5 for mandible) in both jaws. Maxillary lateral incisor in boys showed the greatest change of inclination in both 2 and 4 years (about 7°) and the mandibular canine tooth in girls showed the least change of inclination in 4 years (4°). Sex significantly affected the changes in the inclination of teeth throughout the period of study. The variation of changes in torque was considerable, and no consistent pattern was defined.

This study aimed to compare the shear bond strength (SBS) of ceramic and metal brackets bonded to the enamel using Grengloo color‑change adhesive and Transbond XT conventional composite. In this in vitro, experimental study, 120 extracted human premolars were divided into four groups: (1) Grengloo with metal brackets, (2) Grengloo with ceramic brackets, (3) Transbond XT with metal brackets, and (4) Transbond XT with ceramic brackets. After bracket bonding, the teeth were subjected to 500 thermal cycles and incubated at 37°C for 24 h. The SBS was measured and the data were analyzed using two‑way ANOVA. Mann–Whitney U test was used to compare the Adhesive Remnant Index (ARI) scores. was statistically significant (P < 0.001) The effect of type of bracket (metal/ceramic) on SBS was not statistically significant (P = 0.368). However, the effect of type of composite on SBS was statistically significant (P < 0.001) and the SBS of Grengloo was higher than that of Transbond XT. No significant difference was found in ARI scores among the groups. Regarding the high SBS and the safe region of bond failure in Grengloo composite, this color‑change adhesive can be a suitable alternative in cases that require high bond strength. Furthermore, the color contrast of Grengloo can make composite removal easier than Transbond XT with color match of composite and teeth.

The aim of this study was to compare shear bond strength (SBS) and enamel surface changing of two methods of bonding in rebonding of orthodontic brackets. In this in vitro study, 30 human premolars were randomly classified into three equal groups. Two bonding systems were applied. At first bonding, Group 1 and 2 were bonded by conventional etching and primer technique (CEP) and Group 3 by self‑etching primer (SEP). Thermocycling for 5000 cycles was done. Then, 30 brackets were debonded and SBS and Adhesive remnant index (ARI) were evaluated. One sample was selected from each group, for SEM, 30 new brackets were used for rebonding. Group 1 was bonded by CEP method and Group 2 and 3 were bonded by SEP method. Thermocycling, SBS, ARI, and scanning electron microscope (SEM) were done in the same protocol of the first bonding. One‑way ANOVA, two‑sample t‑test, and Mann–Whitney U‑test were used for statistical analysis. P < 0.05 was considered statistically significant. The mean SBS values were not significantly different between the three groups in the first bonding and rebonding stages (P = 0.22 and 0.24). Further, there was no significant difference between the first bonding and rebonding in SBS values of Groups 1, 2 and 3 (P = 0.44, P = 0.60, and P = 0.56). SEM examination showed obvious differences in the enamel surface between CEP and SEP samples in both first bonding and rebonding. With regard to the advantages of SEP methods, it seems this method can be properly used for rebonding of orthodontic brackets.

This study investigated the effect of two different methods of bleaching during orthodontic treatment on bracket bond strength. A total of 45 extracted premolar teeth were selected in this experimental study and divided into three groups (office bleaching with 35% hydrogen peroxide, home bleaching with 22% carbamide peroxide, and control). The color of the teeth was assessed initially before the application of bleaching agents and Thermocycling. Orthodontic brackets were subsequently bonded on the treated surfaces. Bleaching procedures were then performed. A final color measurement was performed at two points on the buccal surface both underneath and adjacent to the bracket base. The initial and final color measurements and the bond strengths were compared between the groups using the analysis of variance. P < 0.05 was considered as statistically significant. Bracket bond strength was significantly reduced in both bleaching groups compared with the control group (P < 0.01). The color difference before and after the bleaching procedures was significant in the office bleaching group (P < 0.01), while the control group did not demonstrate a statistical difference between initial and final color assessments (P > 0.05). Bleaching procedures performed during orthodontic treatment reduce bond strength. Enamel beneath the bracket base experiences a whitening effect though to a lesser degree compared with an uncovered surface.

The mucous membrane of the maxillary sinus is very sensitive to foreign bodies and infections. Any triggering may lead to mucous membrane thickening (MMT). Residual bone thickness (RBT) is the remaining bone apical to the periodontal defect until the floor of the maxillary sinus acts as a barrier for the periodontal infections to reach the sinus. The aim of our current study was to evaluate the minimal RBT to prevent periodontal infection to reach Schneiderian membrane using cone‑beam computed tomography (CBCT). In this descriptive study, 144 maxillary sinus exposure records of 100 patients were collected retrospectively. Patients with minimum one sinus exposure were considered. MMT and RBT were calculated with the CBCT assistance. Statistical analysis was done using Mann–Whitney U‑test , Kruskal–Wallis and Chi‑square test. (P < 0.05) was considered as statistically significant. Significant difference (P < 0.001) was observed in MMT among three RBT groups. Significantly, higher mean MMT was observed with <2 mm and 2–4 mm RBT groups. The prevalence of MMT with >4 mm group is less (7%) compared to <2 mm group and 2–4 mm RBT groups (91.2% and 90.2%, respectively). Furthermore, there is no significant difference in MMT between angular and furcation defects (P = 0.890). Probability of MMT was increased if RBT is <4 mm. Early detection and prompt periodontal treatments associated with regenerative procedures can be instituted wherever possible to improve RBT and to reduce MMT. Further, microbiological studies are required to confirm the analysis.

The aim of the present study was to compare the marginal seal of self‑adhering flowable composite resin with three universal bonding systems using the self‑etch technique in Cl V cavities at enamel and dentin margins. In this in vitro study, Cl V cavities were prepared on the buccal surfaces of forty premolars, with the occlusal margin of each cavity on enamel and gingival margin on dentin. The teeth were divided into four groups (n = 10) in terms of the adhesive used; Group 1: Vertise Flow (VF) self‑adhering composite resin, Group 2: Clearfil S3 Bond Universal (CS3BU), Group 3: G‑Premio Bond (GPB), Group 4: Single Bond Universal (SBU). In Groups 2, 3, and 4, Z350 flowable composite resin was used to restore the cavities. After thermocycling, the samples were immersed in 10% methylene blue for 24 h and evaluated under a stereomicroscope after buccolingual sectioning; microleakage at enamel and dentin margins was recorded. Kruskal–Wallis and Mann–Whitney tests were used for statistical analyses. Statistical significance was set at P < 0.5. Vertis Flow self‑adhering composite resin exhibited significantly higher microleakage at enamel and dentin margins compared to SBU and CS3BU; however, it had significantly less microleakage at enamel margin compared to GPB (P < 0.05). At the enamel and dentin margins, the minimum microleakage values were recorded at SBU and CS3BU margins, respectively. GPB exhibited the highest microleakage values among the groups evaluated and in all the groups, microleakage at dentin and enamel margins was significantly different (P < 0.05) except for SBU group. The marginal sealing ability of self‑adhering flowable composite resin at enamel and dentin margins was poor compared to the majority of bonding agents evaluated.

Knowledge about the effect of bleaching on behavior of composite resins is important to find a suitable composite resin for restoration of teeth undergoing bleaching. This study aimed to assess the effect of different bleaching protocols on surface roughness and biofilm formation on a silorane‑based composite resin. In this in vitro experimental study, 60 silorane‑based composite resin samples measuring 3 mm in thickness and 6 mm in diameter were fabricated and polished. They were then randomly divided into four groups (n = 15). In Group 1, samples were stored in distilled water as control. Samples in Groups 2, 3, and 4 were subjected to bleaching with 15% carbamide peroxide, 35% hydrogen peroxide, and 35% hydrogen peroxide activated by light, respectively. Surface roughness was measured using a profilometer. Streptococcus mutans cultured in brain‑heart infusion broth was used for the assessment of biofilm formation on the samples. The bacterial colonies were counted using the pure‑plate technique. Data were analyzed using one‑way ANOVA and post hoc Tukey’s tests. Regression model was used to assess the association between surface roughness and biofilm formation (P < 0.05). The mean surface roughness of the four groups was not significantly different (P = 0.11); however, a significant difference was noted in the mean biofilm formation among the groups (P = 0.00). Bleaching decreased biofilm formation. The lowest biofilm formation was noted in the group subjected to light‑activated 35% hydrogen peroxide. Increased surface roughness enhanced biofilm formation to a certain level; excessive roughness did not increase biofilm formation.

Dental status is one of the main indicators of overall health. We examined it in children aged 6–15 years who live in conditions of biogeochemical fluorine and iodine deficiency (Transcarpathian region, Ukraine), to improve the quality of dental care. In this cross sectional study To assess the state of teeth, we used indicators recommended by the WHO Expert Committee. The prevalence and intensity of dental caries, periodontal status, oral hygiene status and dentoalveolar anomalies were determined using a questionnaire and descriptive analyses was done (P < 0.05). The total prevalence of caries in deciduous teeth in children was 57.86% ± 1.56%, with intensity of 2.61 ± 0.6. The total prevalence of caries in permanent teeth was 71.45% ± 1.31%, with intensity of 2.36 ± 0.52. Analysis of the results showed a high prevalence of periodontal disease, which increases with age. The level of oral hygiene was evaluated as unsatisfactory. Studying the prevalence of dentoalveolar anomalies showed the lowest prevalence (40.05% ± 2.56%) at the age of 6 years and the maximum value at 12 years (77.20% ± 2.75%). In addition, we found poor hygienic knowledge of the parents, lack of medical activity of parents to preserve dental health of the child, lack of dentists’ work on hygiene education, and public health education for prevention of dental diseases. On the other hand, a high level of confidence was revealed in the information received from dentists. The high prevalence of leading dental diseases requires modernization of the existing prevention programs for children.