The prevalence of developmental defects of enamel in people with cystic fibrosis: a systematic review.

BACKGROUND: Oral health impacts systemic health, individual well-being, and quality of life. It is important to identify conditions that may exacerbate oral disease to aid public health and policy development and promote targeted patient treatment strategies. Developmental defects can increase an individual's risk of dental caries, hypersensitivity, premature tooth wear, erosion, and poor aesthetics. As part of an ongoing study assessing oral health in adults with cystic fibrosis at Cork University Dental School and Hospital, a systematic review of available literature was conducted to assess the prevalence of enamel defects in people with cystic fibrosis. AIMS: To critically evaluate the literature to determine if the prevalence of developmental defects of enamel is higher in people with cystic fibrosis (PwCF). METHODS: Data Sources: Three online databases were searched Embase, Scopus, and Web of Science Core Collection. Studies that examined an association between cystic fibrosis and developmental defects of enamel were included in this systematic review. RESULTS: The initial search identified 116 publications from the following databases Embase, Web of Science Core Collection, and Scopus. Eleven studies were included for qualitative analysis. Nine studies concluded that PwCF had a higher prevalence of enamel defects than control people and one study found no difference in cystic fibrosis (CF) status. All studies had a risk of bias that may influence study results and their interpretation. CONCLUSIONS: The results of the systematic review show a consistent pattern that PwCF have a higher prevalence of DDE than people without CF. Genetic dysfunction, chronic systemic infections, and long-term antibiotic use are possible aetiological causes. This review highlights the need for future studies to investigate if DDEs are caused by the underlying CFTR mutation or as a consequence of disease manifestations and/or management.

Enamel changes of bleached teeth following application of an experimental combination of chitosan-bioactive glass.

BACKGROUND: Considering the extensive use of bleaching agents and the occurrence of side effects such as enamel demineralization, this study aimed to assess the enamel changes of bleached teeth following the experimental application of chitosan-bioactive glass (CH-BG). METHODS: In this in vitro study, CH-BG (containing 66% BG) was synthesized and characterized by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Thirty sound human premolars were bleached with 40% hydrogen peroxide, and the weight% of calcium and phosphorus elements of the buccal enamel surface was quantified before and after bleaching by scanning electron microscopy/ energy-dispersive X-ray spectroscopy (SEM, EDX). Depending on the surface treatment of the enamel surface, the specimens were divided into three groups (n = 10): control (no treatment), MI Paste (MI), and CH-BG. Then the specimens were stored in artificial saliva for 14 days. The SEM/EDX analyses were performed again on the enamel surface. Data were analyzed by one-way ANOVA and Tukey's test and a p-value of < 0.05 was considered statistically significant. RESULTS: In all groups, the weight% of calcium and phosphorus elements of enamel decreased after bleaching; this reduction was significant for phosphorus (p < 0.05) and insignificant for calcium (p > 0.05). After 14 days of remineralization, the weight% of both calcium and phosphorus elements was significantly higher compared to their bleached counterparts in both MI and CH-BG groups (p < 0.05). Following the remineralization process, the difference between MI and CH-BG groups was not significant (p > 0.05) but both had a significant difference with the control group in this regard (p < 0.05). CONCLUSIONS: The synthesized CH-BG compound showed an efficacy comparable to that of MI Paste for enamel remineralization of bleached teeth.

Influence of maternal cholesterol-enriched diet on chemical composition of teeth enamel in offspring of mice.

OBJECTIVE: Aim: To determine the chemical composition of the tooth enamel of two-day-old mice from hypercholesterolemic mothers by energy dispersive X-ray spectroscopy. PATIENTS AND METHODS: Materials and Methods: Forty mature female mice were randomly assigned (n = 20/group) to either a standard chow vivarium diet (control group) or a cholesterol-enriched chow diet (experimental group). After fertilization, pregnancy and birth, on postnatal day 2, the incisor segments of 6 pups form each group were used for energy dispersive X-ray spectroscopy. RESULTS: Results: Influence of maternal hypercholesterolemic diet on tooth development and mineralization was examined, which revealed changes in enamel chemical composition. First, the results indicate the presence of seven elements (Na, Cl, Ca, P, Mg, S, Fe) in the enamel of both the hypercholesterolemic and normal offspring, but the content of element Ca2+ decreased, the content of elements P5+, Na+, Cl- tended to increase in pups from hypercholesterolemic mice. Second, the initial level of mineralization according to the atomic (%) Ca / P in hypercholesterolemic pups ratio was 1.26, comparing with normal pups where level of mineralization was 1.34. Taking into account that irreversible changes in the structure of the enamel were observed when the Ca / P ratio was below 1.33, we can suggest that the eruption of teeth with an imperfect structure could be because of maternal hypercholesterolemic diet. CONCLUSION: Conclusions: Results of this study suggest that hypercholesterolemic diet during gestation and lactation leads to altered enamel mineralization in mice because of changes in chemical composition and may link to the early childhood caries.

The erosive effect of pomegranate juice on enamel: An in vitro study.

AIM: Dental erosion is a chemical-mechanical process that leads to the loss of dental hard tissues. This study aimed to investigate the effect of pomegranate juice on the enamel. METHODS: Enamel blocks were randomly divided into three groups: deionized water, cola, and pomegranate juice. The blocks were immersed in the solutions four times a day for 14 days, and stored in artificial saliva for the remaining period. The surface hardness was measured on days 7 and 14. The surface structures of the demineralized blocks were observed via scanning electron microscopy (SEM), and the depth of demineralization was observed via confocal laser scanning microscopy (CLSM). The pH, calcium, and phosphorus levels of the three solutions were analyzed. RESULTS: The microhardness values of the blocks in the pomegranate juice and cola groups decreased with the increase in the demineralization time. The blocks in the pomegranate juice group exhibited large fractures in the enamel column, whereas those in the cola group had pitted enamels with destruction of the interstitial enamel column. Compared with cola group, fluorescent penetration increased in pomegranate juice (P < 0.01). The pH of cola (2.32 ± 0.09) was lower than that of pomegranate juice (3.16 ± 0.16). Furthermore, the calcium content in pomegranate juice was significantly higher than that in cola (P < 0.01). Alternatively, the concentration of phosphorous in cola was significantly higher than that in pomegranate juice (P < 0.01). CONCLUSION: These findings indicate that pomegranate juice can cause enamel demineralization with an erosive potential comparable to that of cola.

Bayesian modeling of spatially differentiated multivariate enamel defects of the children's primary maxillary central incisor teeth.

BACKGROUND: The analysis of dental caries has been a major focus of recent work on modeling dental defect data. While a dental caries focus is of major importance in dental research, the examination of developmental defects which could also contribute at an early stage of dental caries formation, is also of potential interest. This paper proposes a set of methods which address the appearance of different combinations of defects across different tooth regions. In our modeling we assess the linkages between tooth region development and both the type of defect and associations with etiological predictors of the defects which could be influential at different times during the tooth crown development. METHODS: We develop different hierarchical model formulations under the Bayesian paradigm to assess exposures during primary central incisor (PMCI) tooth development and PMCI defects. We evaluate the Bayesian hierarchical models under various simulation scenarios to compare their performance with both simulated dental defect data and real data from a motivating application. RESULTS: The proposed model provides inference on identifying a subset of etiological predictors of an individual defect accounting for the correlation between tooth regions and on identifying a subset of etiological predictors for the joint effect of defects. Furthermore, the model provides inference on the correlation between the regions of the teeth as well as between the joint effect of the developmental enamel defects and dental caries. Simulation results show that the proposed model consistently yields steady inferences in identifying etiological biomarkers associated with the outcome of localized developmental enamel defects and dental caries under varying simulation scenarios as deemed by small mean square error (MSE) when comparing the simulation results to real application results. CONCLUSION: We evaluate the proposed model under varying simulation scenarios to develop a model for multivariate dental defects and dental caries assuming a flexible covariance structure that can handle regional and joint effects. The proposed model shed new light on methods for capturing inclusive predictors in different multivariate joint models under the same covariance structure and provides a natural extension to a nested hierarchical model.

Effect of different brushing parameters on erosive tooth wear in primary bovine enamel and dentin.

This in-vitro study aimed to analyse the effect of brushing and different brushing parameters (kind of toothpaste, kind of toothbrush, brushing force) on erosive tooth wear of primary bovine enamel and dentin. Specimens were prepared from primary bovine enamel or dentin (each group n = 12) and cyclically eroded (6 × 60 s/d, citric acid, pH 2.4) and brushed with children's toothbrushes (2 × 15 s/d) over 5 days. The brushing parameters under investigation were: toothpaste (fluoridated, fluoride-free), toothbrush (manual; rotating-oscillating and sonic, each at two different activation modes) and brushing force (1 N, 2 N). Specimens that were only eroded and not brushed served as controls. Enamel and dentin wear was quantified using widefield confocal microscopy. Statistical analysis was performed using three- and one-way ANOVAs followed by Scheffe's (enamel) or Tamhane's (dentin) post-hoc tests (p < 0.05). Brushing with the fluoridated toothpaste was able to significantly reduce erosive wear in enamel (by 15 to 37%, 6 of 10 groups) and in dentin (by 58 to 72%, all groups), while brushing with the fluoride-free toothpaste was not different from the controls. Considering the kind of toothpaste and brushing force, slight differences between the toothbrushes were observed in enamel, but not in dentin. Within the same toothbrush and activation mode, almost no differences between 1 and 2 N brushing force were detected. In conclusion, erosive tooth wear on primary bovine dental hard tissue mainly depends on the kind of toothpaste, rather than on the kind of toothbrush and the brushing force.

A Wnt10a-Notch signaling axis controls Hertwig's epithelial root sheath cell behaviors during root furcation patterning.

Human with bi-allelic WNT10A mutations and epithelial Wnt10a knockout mice present enlarged pulp chamber and apical displacement of the root furcation of multi-rooted teeth, known as taurodontism; thus, indicating the critical role of Wnt10a in tooth root morphogenesis. However, the endogenous mechanism by which epithelial Wnt10a regulates Hertwig's epithelial root sheath (HERS) cellular behaviors and contributes to root furcation patterning remains unclear. In this study, we found that HERS in the presumptive root furcating region failed to elongate at an appropriate horizontal level in K14-Cre;Wnt10afl/fl mice from post-natal day 0.5 (PN0.5) to PN4.5. EdU assays and immunofluorescent staining of cyclin D1 revealed significantly decreased proliferation activity of inner enamel epithelial (IEE) cells of HERS in K14-Cre;Wnt10afl/fl mice at PN2.5 and PN3.5. Immunofluorescent staining of E-Cadherin and acetyl-α-Tubulin demonstrated that the IEE cells of HERS tended to divide perpendicularly to the horizontal plane, which impaired the horizontal extension of HERS in the presumptive root furcating region of K14-Cre;Wnt10afl/fl mice. RNA-seq and immunofluorescence showed that the expressions of Jag1 and Notch2 were downregulated in IEE cells of HERS in K14-Cre;Wnt10afl/fl mice. Furthermore, after activation of Notch signaling in K14-Cre;Wnt10afl/fl molars by Notch2 adenovirus and kidney capsule grafts, the root furcation defect was partially rescued. Taken together, our study demonstrates that an epithelial Wnt10a-Notch signaling axis is crucial for modulating HERS cell proper proliferation and horizontal-oriented division during tooth root furcation morphogenesis.

Evaluation of enamel surface integrity after orthodontic bracket debonding: comparison of three different system.

OBJECTIVE: This study aimed to evaluate enamel surface integrity and time consumed during residual cement removal after bracket debonding using different adhesive removal burs with and without a dental loupe. MATERIAL AND METHODS: Sixty human-extracted premolars were collected, cleaned, mounted, and prepared for orthodontic bracket bonding. Teeth were randomly divided into three main groups (n = 20) based on the adhesive removal method: tungsten carbide system (TC), sof-lex discs system (SD), and diamond system (DB) groups. Then, each group was subdivided into two subgroups (naked eye and magnifying loupe subgroups). The brackets were bonded and then debonded after 24 h, and the Adhesive Remnant Index (ARI) was assessed. The adhesive remnants were removed by different systems, and the final polishing was performed by Silicone OneGloss. The enamel surface roughness was evaluated before bracketing (T0), after residual cement removal (T1), and finally after polishing (T2) using surface Mitutoyo SJ-210 profilometry and Scanning Electron Microscopy (SEM) to determine the Enamel Damage Index (EDI) score. The time consumed for adhesive removal was recorded in seconds. RESULTS: The Kruskal Wallis test showed a statistically significant difference in roughness values at T1 compared to T2 between subgroups (p < 0.001). When comparing EDI at T1 and T2, the Kruskal-Wallis H-test showed statistically significant differences in all subgroups. The pairwise comparisons revealed that EDI scores showed a statistically significant difference at T1 and T2 between DB vs. TC and SD (p = 0.015) but not between TC vs. SD (p = 1.000), indicating the highest roughness value observed in the DB group. The time for cement removal was significantly shorter in the magnifying loupe group than in the naked eye group and was shortest with the TC group, whereas the time was the longest with the DB group (p < 0.05). CONCLUSION: All three systems were clinically satisfactory for residual orthodontic adhesive removal. However, TC system produced the lowest enamel roughness, while the DB system created the greatest. The polishing step created smoother surfaces regardless of the systems used for resin removal.

Aesthetic impact of resin infiltration and its mechanical effect on ceramic bonding for white spot lesions.

BACKGROUND: Treating white spot lesions (WSLs) with resin infiltration alone may not be sufficient, raising questions about its compatibility with other treatments amid controversial or incomplete data. Therefore, this study aimed to assess the aesthetic feasibility of resin infiltration combined with bleaching, as well as its potential mechanical effect on ceramic bonding to WSLs. METHODS: One hundred and fifty flat enamel surfaces of bovine incisors were prepared. Ninety specimens were deminerailized and randomly assigned to three groups(n = 30): post-bleaching resin infiltration (Bl-R), pre-bleaching resin infiltration (R-Bl), and only resin infiltration (R). Color, surface roughness and microhardness were assessed in immediate, thermocycling and pigmentation tests. The remaining sixty samples were randomly assigned to three groups (n = 20): control (Ctrl), bonding (Bo), pre-bonding resin infiltration (R-Bo). Shear bonding strength, failure mode, micro-leakage depth and interface morphology were evaluated after ceramic bonding. The Tukey test and analysis of variance (ANOVA) were used for statistical analysis. RESULTS: For the effect of resin infiltration and bleaching on WSLs, the R-Bl group showed the worst chromic masking ability, with the highest |ΔL|, |Δa|, |Δb|, and ΔE values after treatment. Compared with those in the Bl-R group, the R-Bl and R groups showed significant time-dependent staining, which is possibly attributed to their surface roughness. For the effect of resin infiltration on the adhesive properties of WSLs, resin infiltration reduced the staining penetration depth of WSLs from 2393.54 ± 1118.86 µm to 188.46 ± 89.96 µm (P < 0.05) while reducing WSLs porosity in SEM observation. CONCLUSIONS: Post-bleaching resin infiltration proved to be advantageous in the aesthetic treatment of WSLs. Resin infiltration did not compromise bonding strength but it did reduce microleakage and enhance marginal sealing. Overall, resin infiltration can effectively enhance the chromatic results of treated WSLs and prevent long-term bonding failure between ceramics and enamel. Based on these findings, the use of post-bleaching resin infiltration is recommended, and resin infiltration before ceramic bonding is deemed viable in clinical practice.

75 Years Ago: Discovery of Resin Adhesion to Acid-etched Enamel - A Comparison of the 1949 and 1955 Methods.

PURPOSE: This paper describes previously unknown details about the discovery of resin adhesion to acid-etched human enamel. MATERIALS AND METHODS: A literature review was performed through manual assessments. Primary sources revealing the discovery of resin curing on etched enamel were analyzed considering the research objectives and methodological procedure during that era, including the type of teeth used, preparatory measures, acid-etching process, type of resin and its application, and follow-up observations. Additionally, the political and economic contexts were examined. RESULTS: In 1949, acid etching was found to promote adhesion with acrylic resin, a finding described again in 1955. The 1949 studies utilized nitric acid for enamel etching and the acrylate resin Paladon from the Kulzer company (Germany). Conversely, the 1955 investigations employed phosphoric acid and an unnamed acrylate, likely a self-curing resin supported by Kulzer in the late 1930s. Disparities in the 1949 and 1955 findings can be ascribed to varying objectives and test conditions amidst a turbulent political backdrop, significantly impacting the Kulzer company. CONCLUSION: The discovery of resin adhesion to acid-etched enamel, approaching its 75th anniversary in 2024, is a landmark in 20th-century adhesive dentistry. Paladon represents a pioneering compound, exemplifying the influence of political, ideological, and economic factors on scientific advancements during that period.

FAM20A-Associated Amelogenesis Imperfecta: Gene Variants with Functional Verification and Histological Features.

OBJECTIVE: To investigate FAM20A gene variants and histological features of amelogenesis imperfecta and to further explore the functional impact of these variants. METHODS: Whole-exome sequencing (WES) and Sanger sequencing were used to identify pathogenic gene variants in three Chinese families with amelogenesis imperfecta. Bioinformatics analysis, in vitro histological examinations and experiments were conducted to study the functional impact of gene variants, and the histological features of enamel, keratinised oral mucosa and dental follicle. RESULTS: The authors identified two nonsense variants c. 406C > T (p.Arg136*) and c.826C > T (p.Arg176*) in a compound heterozygous state in family 1, two novel frameshift variants c.936dupC (p.Val313Argfs*67) and c.1483dupC (p.Leu495Profs*44) in a compound heterozygous state in family 2, and a novel homozygous frameshift variant c.530_531insGGTC (p.Ser178Valfs*21) in family 3. The enamel structure was abnormal, and psammomatoid calcifications were identified in both the gingival mucosa and dental follicle. The bioinformatics and subcellular localisation analyses indicated these variants to be pathogenic. The secondary and tertiary structure analysis speculated that these five variants would cause structural damage to FAM20A protein. CONCLUSION: The present results broaden the variant spectrum and clinical and histological findings of diseases associated with FAM20A, and provide useful information for future genetic counselling and functional investigation.

Japanese 17q12 Deletion Syndrome with Complex Clinical Manifestations.

17q12 deletion syndrome is a rare chromosomal anomaly with variable phenotypes, caused by the heterozygous deletion of chromosome 17q12. We herein report a 35-year-old Japanese patient with chromosomal 17q12 deletion syndrome identified by de novo deletion of the 1.46 Mb segment at the 17q12 band by genetic analyses. He exhibited a wide range of phenotypes, such as maturity-onset diabetes of the young (MODY) type 5, structural or functional abnormalities of the kidney, liver, and pancreas; facial dysmorphic features, electrolyte disorders; keratoconus, and acquired perforating dermatosis. This case report provides valuable resources concerning the clinical spectrum of rare 17q12 deletion syndrome.

Prenatal exposure to environmental toxins and comprehensive dental findings in a population cohort of children.

Environmental toxins are known to have many impacts on growth and development in humans, starting in utero. Alterations in amelogenesis, caused by chemical and physical trauma that occur during the antenatal, perinatal and postnatal time periods, may result in developmental defects in deciduous and permanent tooth enamel, as demonstrated in animal studies. These defects can be clinically visible and result in a variety of morphological and functional problems in the dentition. Since enamel does not remodel after formation, it may serve as a permanent record of insults during organ development.Our primary purpose was to investigate any possible relationship between intrauterine exposure to endocrine disrupting chemicals (phenols and phthalates) and developmental defects in enamel in children, while also accounting for fluoride exposure. Our secondary purpose was to report descriptively on findings from comprehensive dental examinations performed on 356 children that were drawn from the general paediatric population. A cohort of children from the Utah Children's Project (N = 356) that had full medical exams, comprehensive medical and family histories and available biospecimens were given extraoral and intraoral examinations. They also completed an oral health questionnaire. Standardized intraoral photographs were taken of the teeth and viewed by standardised examiners and the dental observations were recorded for a full inventory of findings, including: tooth morphology, caries, restorations, colorations, attrition, erosion, fractures and hypomineralization. Perinatal maternal urine samples were assessed for the concentration of fluoride, phenols and phthalates, including bisphenol A (BPA).Pairwise statistical analyses were done to correlate the dental findings with one another and with the presence of environment chemicals found in the urine samples. Hypomineralization was the most common finding (96% of children; 37% of deciduous teeth, 42% of permanent teeth), consistent with molar incisor hypomineralization (MIH) described in other human populations. No consistent correlations were seen between dental findings and the presence of phenols and phthalates in prenatal urine, but the number of samples available for the assessment was limited (n = 35).In conclusion, we found a high proportion of dental hypomineralization in a population based paediatric cohort, but did not find an association with prenatal exposure to phenols and phthalates.

The effect of combined use of resin infiltration with different bioactive calcium phosphate-based approaches on enamel white spot lesions: An in vitro study.

OBJECTIVES: This in vitro study aimed to evaluate the effect of resin infiltration combined with casein phosphopeptide-amorphous calcium phosphate with fluoride (CPP-ACPF) or bioactive glass (BAG) on the stability of enamel white spot lesions (WSLs) treatment. MATERIALS AND METHODS: Eighty-four enamel blocks were prepared from the buccal surfaces of sound human premolars. All enamel blocks were placed in a demineralisation solution for 3 days to establish the artificial enamel WSLs. Enamel blocks with WSLs were randomly divided into three groups (n = 28 each group): RI/B: one-off resin infiltration followed by twice daily BAG treatment; RI/C: one-off resin infiltration followed by twice daily CPP-ACPF treatment; RI: one-off resin infiltration treatment only (as control) and subjected to pH cycling for 7 days. Surface morphology, elemental analysis, crystal characteristics, surface roughness and microhardness of enamel surfaces were investigated by scanning electron microscopy and energy-dispersive spectrometry observation, X-ray diffraction (XRD), atomic force microscope and Vickers' hardness testing, respectively. RESULTS: Mean values of the surface roughness (mean±standard deviation (nm)) were 24.52±5.07, 27.39±5.87 and 34.36±4.55 for groups RI/B, RI/C and RI respectively (p = 0.003). The calcium to phosphate ratios were 1.32±0.16, 1.22±0.26 and 0.69±0.24 for groups RI/B, RI/C and RI respectively (p < 0.001). XRD revealed apatite formation in all three groups. The mean enamel surface microhardness (kg/mm2) of the groups were 353.93±28.49, 339.00±27.32 and 330.38±22.55 for groups RI/B, RI/C and RI respectively (p = 0.216). CONCLUSIONS: Resin infiltration combined with CPP-ACPF or BAG remineralisation appears to improve the surface properties of WSLs. CLINICAL SIGNIFICANCE: The combination of resin infiltration and CPP-ACPF/BAG remineralisation may be a potential treatment for the management of the WSLs.

Evaluation of Stain Removal Efficacy and Color Stability of Three Different Dentifrices on Artificially Stained Enamel Surface-An In Vitro Study.

AIM: The aim of the present study was to assess the stain removal ability and color stability of three distinct dentifrices on artificially stained enamel surface. MATERIALS AND METHODS: This study included 75 intact, healthy premolars free of dental caries that were extracted during orthodontic therapy. The samples were allowed to dry for 6 hours after being submerged in the prepared tea solution for roughly 18 hours every day. Then this procedure was repeated for seven successive days. All samples were randomly divided into three experimental groups with 25 samples in each group. Group I: control dentifrice, group II: dentifrice containing hydrogen peroxide, group III: dentifrice containing papain and bromelain. A specially designed toothbrushing simulator was used to brush every sample in the relevant group. Using a spectrophotometer and a measurement program, color measurement was evaluated after staining process after 4 weeks and 8 weeks of teeth cleaning. Using a profilometer, the surface roughness values (Ra) were assessed. RESULTS: After 8 weeks of brushing of stained samples, the color stability was better in dentifrice containing hydrogen peroxide (1.14 ± 0.11) followed by dentifrice containing papain and bromelain (1.22 ± 0.08) and control group (1.30 ± 0.09). And after 8 weeks of brushing of stained samples, the surface roughness was more in dentifrice containing hydrogen peroxide (0.237 ± 0.02) followed by dentifrice containing papain and bromelain (0.229 ± 0.13) and control group (0.207 ± 0.05). CONCLUSION: The present study concluded that the dentifrice containing hydrogen peroxide showed a superior whitening effect on the stained enamel surface than dentifrice containing papain and bromelain and control dentifrice. CLINICAL SIGNIFICANCE: The development of various dentifrice products has been greatly aided by the increased demand for an improved esthetic appearance. Teeth's natural color and any external stains that could accumulate on the tooth surface combine to determine a tooth's color. Additionally, the use of whitening dental pastes to remove external stains has grown in favor. With the development of these whitening toothpastes, dentifrices' ability to lessen or eliminate extrinsic dental stains has increased. How to cite this article: Mishra D, Kamath DG, Alagla M, et al. Evaluation of Stain Removal Efficacy and Color Stability of Three Different Dentifrices on Artificially Stained Enamel Surface-An In Vitro Study. J Contemp Dent Pract 2024;25(1):68-71.

Influence of coating dental enamel with a TiF4-loaded polymeric primer on the adverse effects caused by a bleaching gel with 35% H2O2.

OBJECTIVE: To evaluate whether coating enamel with a polymeric primer (PPol) containing titanium tetrafluoride (TiF4) before applying a bleaching gel with 35% H2O2 (35% BG) increases esthetic efficacy, prevents changes in morphology and hardness of enamel, as well as reduces the cytotoxicity from conventional in-office bleaching. MATERIALS AND METHODS: Standardized enamel/dentin discs were stained and bleached for 45 min (one session) with 35% BG. Groups 2TiF4, 6TiF4, and 10TiF4 received the gel on the enamel previously coated with PPol containing 2 mg/mL, 6 mg/mL, or 10 mg/mL, respectively. No treatment or application of 35% BG directly on enamel were used as negative control (NC), and positive control (PC), respectively. UV-reflectance spectrophotometry (CIE L*a*b* system, ΔE00, and ΔWI, n = 8) determined the bleaching efficacy of treatments. Enamel microhardness (Knoop, n = 8), morphology, and composition (SEM/EDS, n = 4) were also evaluated. Enamel/dentin discs adapted to artificial pulp chambers (n = 8) were used for trans-amelodentinal cytotoxicity tests. Following the treatments, the extracts (culture medium + bleaching gel components diffused through the discs) were collected and applied to odontoblast-like MDPC-23 cells, which were assessed concerning their viability (alamarBlue, n = 8; Live/Dead, n = 4), oxidative stress (n = 8), and morphology (SEM). The amount of H2O2 in the extracts was also determined (leuco crystal violet/peroxidase, n = 8). The numerical data underwent one-criterion variance analysis (one-way ANOVA), followed by Tukey's test, at a 5% significance level. RESULTS: Regarding the ΔE00, no difference was observed among groups 2TiF4, 6TiF4, and PC (p > 0.05). The ΔWI was similar between groups 2TiF4 and PC (p > 0.05). The ΔWI of group 6TiF4 was superior to PC (p < 0.05), and group 10TiF4 achieved the highest ΔE00 and ΔWI values (p < 0.05). Besides limiting enamel microstructural changes compared to PC, group 10TiF4 significantly increased the hardness of this mineralized dental tissue. The highest cellular viability occurred in 10TiF4 compared to the other bleached groups (p < 0.05). Trans-amelodentinal H2O2 diffusion decreased in groups 2TiF4, 6TiF4, and 10TiF4 in comparison with PC (p < 0.05). CONCLUSION: Coating enamel with a PPol containing TiF4 before applying a 35% BG may increase enamel microhardness and esthetic efficacy and reduce the trans-amelodentinal cytotoxicity of conventional in-office tooth bleaching. The PPol containing 10 mg/mL of TiF4 promoted the best outcomes.

Coffee-stained tooth enamel color restoration and surface abrasion with whitening and regular toothpaste.

PURPOSE: To evaluate the effectiveness of whitening toothpaste in restoring tooth color after coffee staining and its potential impact on enamel surfaces compared with regular toothpaste. METHODS: Bovine tooth enamel specimens were prepared and stained with coffee solutions before undergoing brushing simulation with different toothpaste slurries (whitening, regular, reference). For precise evaluation, spectrophotometric measurements were taken at intervals to assess color changes using the CIELAB (Commission Internationale de l'Éclairage Lab*) color space. Additionally, profilometric measurements were taken to determine the impact of toothpaste type on the roughness and abraded depth of the enamel surface. To understand the effects of toothpaste and brushing on color change, surface roughness, and abraded depth, while also considering correlations between these factors, the findings were analyzed using mixed-effects models. RESULTS: The whitening toothpaste group demonstrated the highest recovery rate (71%) after 10,000 brushstrokes, followed by the regular toothpaste group (48%) and the reference slurry group (43%). The mixed-effects model analysis revealed that the reference group had a smaller change in lightness (ΔL) than those in the regular toothpaste group. The whitening toothpaste group showed a greater change in lightness on average than those in the regular toothpaste group, with an increase in lightness as the number of brushstrokes increased. According to the roughness and abraded depth data, the whitening toothpaste group was least affected by brushing, while the reference and regular toothpaste groups showed higher levels of roughness and abraded depth at all intervals. CLINICAL SIGNIFICANCE: Gaining a thorough understanding of the effectiveness of whitening toothpaste and its impact on the enamel surface plays a crucial role in refining toothpaste formulations and advancing tooth whitening techniques in dental care.

Effect of ultrasonic and sonic instrumentation on shear bond strength of resin composite to enamel: An in vitro study.

PURPOSE: To assess and compare the effects of sonic and ultrasonic instrumentation on shear bond strength (SBS) and investigate the influence of adhesive system application modes (etch&rinse/self-etch) on SBS. METHODS: In this experimental study, 45 extracted sound human molars were selected. Mesial and distal surfaces of the teeth were abraded until 90 smooth enamel surfaces were obtained. Specimens were divided into two groups, with half (N= 45) conditioned in etch&rinse mode and the remaining (N= 45) in self-etch mode using Tetric N Bond Universal. Composite resin discs were produced on these surfaces by filling Teflon molds. All specimens were aged via thermocycling. Each group was further divided into three more groups (n= 15) according to the type of periodontal instrumentation (ultrasonic, sonic or none). SBS values were recorded and analyzed using two-way ANOVA. Fracture sites were examined under a stereomicroscope. RESULTS: The type of periodontal instrumentation had no significant effect on SBS values, whether sonic, ultrasonic or their absence (P= 0.945). The type of adhesive system mode had a significant influence on the shear bond strength values. Etch&rinse groups had significantly higher shear bond strength values than self-etch groups (P< 0.001). CLINICAL SIGNIFICANCE: This study reassures practitioners that sonic and ultrasonic instruments are safe for enamel bonding and highlights the importance of selecting adhesive techniques for optimal restorative outcomes.

Effects of particle size, storage conditions, and chemical pretreatments on carbon and oxygen isotopic measurements of modern tooth enamel.

Isotopic analysis of human tooth enamel can provide life history information useful in forensic identification. These applications depend on the availability of reference data documenting isotopic values for individuals with known life history and on the comparability of data from reference and case work samples. Here we build on previous methodological research, which has largely focused on paleontological and archaeological samples, and conduct experiments using enamel from modern human teeth targeting three sample preparation variables (sample particle size, storage conditions, and chemical pretreatments). Our results suggest that differences in particle size affect the efficiency of sample reactions during pretreatment and analysis, with coarse particles giving reduced loss of enamel carbonate during acid pretreatments but producing slightly higher oxygen isotope values than fine particles during analysis. Data for samples stored in dry and ambient environments following pretreatment were indistinguishable, suggesting no exchange of oxygen between samples and ambient water vapor. Finally, chemical pretreatments with a range of commonly used reactants and conditions showed a pervasive, moderate oxygen isotope shift associated with acetic acid treatment, which may be caused by exchange of enamel hydroxyl groups with reagents or rinse waters. Collectively, the results emphasize the importance of methodological standardization to improve comparability and reduce potential for bias in the forensic application of tooth enamel isotope data.

Effect of composite radiopacity and margin location of the restoration on the diagnosis of secondary caries.

This research aimed to evaluate the effect of the radiopacity of a Bulk-Fill composite (X-TraFil, VOCO, Germany) and a Conventional composite (P60, 3M ESPE, USA) and assessment of the margin location in the enamel and dentin on the diagnosis of secondary caries. 76 intact premolars with MOD preparation were divided into two equal groups and filled with the conventional and bulk-fill composite. Four regions were considered to simulate carious lesions (two regions in enamel and two regions in dentin). In each group, half of the regions in the dentin and half in the enamel were randomly selected for secondary caries simulation and filled with a wax-plaster combination while the remaining regions stayed intact. Bitewing imaging was done using the PSP digital sensor. Five examiners reviewed the images, and lesions were recorded. Caries diagnosis indicators and paired-sample t-test were used for statistical analysis. The reproducibility and accuracy of the examiners' responses were evaluated using the kappa and agreement coefficient (α=0.05). The sensitivity, specificity, and accuracy of diagnosing secondary carious lesions in enamel were significantly better under conventional than bulk-fill composite. Similarly, the sensitivity and accuracy of diagnosing secondary caries in dentin were significantly higher under conventional composite than bulk-fill composite (p<0.05). No significant differences were found in the agreement and kappa coefficient between conventional and bulk-fill composites in the enamel and dentin (p>0.05). The diagnostic accuracy of carious lesions was higher under conventional composite than bulk-fill composite. However, the location of the secondary was ineffective in caries diagnosis.