Proteomic analysis of stimulated saliva in gastroesophageal reflux disease patients with and without erosive tooth wear: Observational study.

OBJECTIVE: To evaluate the difference in the proteomic profile of stimulated saliva in patients with gastroesophageal reflux disease (GERD) with (GE) and without (GNE) erosive tooth wear (ETW), regarding both human and bacterial proteins. METHODS: Stimulated saliva (SS) was collected from 16 patients (8/group). Samples were centrifuged at 4.500 g for 15 min under refrigeration to remove all debris. The supernatant from each saliva sample was taken and frozen at -80 °C. After extracting the proteins, they were submitted to reverse phase liquid chromatography and mass spectrometry (nLC-ESI-MS/MS). Label-free proteomic quantification was performed using Protein Lynx Global Service (PLGS) software (p < 0.05) for human and bacterial proteins. RESULTS: In total, 67 human proteins were common for GNE and GE groups. GNE group presented, compared to GE group, increase in proteins that confer antimicrobial and acid resistant properties, such as cystatins, histatin and immunoglobulins. However, GNE group had a marked decrease in subunits of hemoglobin (α, ß and delta). Regarding bacterial proteins, for SS, 7 and 10 unique proteins were identified in the GE and GNE groups, respectively. They are related to protein synthesis and energy metabolism and interact with human proteins typically found in saliva and supramolecular complexes of the acquired pellicle. CONCLUSIONS: Our data indicate that the stimulation of the salivary flow increases acid resistant and antimicrobial proteins in saliva, which might protect against ETW. CLINICAL SIGNIFICANCE: This pioneer study showed important differences in the human and bacterial proteome of SS in patients with GERD with or without ETW.

Radiotherapy changes acquired enamel pellicle proteome in head and neck cancer patients.

OBJECTIVES: To evaluate in vivo the proteomic profile of the acquired enamel pellicle (AEP) in patients with head and neck cancer (HNC) before, during and after radiotherapy. METHODS: Nine patients, after prophylaxis, had their AEPs collected before (BRT), during (DRT; 2-5 weeks) and after (ART; 3-4 months) radiotherapy. AEP was also collected from nine healthy patients (Control). The proteins were extracted in biological triplicate and processed by label-free proteomics. RESULTS: Statherin was increased more than 9-fold and several hemoglobin subunits were increased more than 5-fold DRT compared to BRT, while lactotransferrin, proline-rich proteins, cystatins, neutrophil defensins 1 and 3 and histatin-1 were decreased. ART, there was an increase in lactotransferrin and several isoforms of histones, while statherin and alpha-amylase proteins were decreased. MOAP-1 was exclusively found ART in comparison to BRT. When compared to Control, AEP of patients BRT showed an increase in proteins related to the perception of bitter taste, mucin-7 and alpha-amylases, while cystatin-S was decreased. CONCLUSIONS: HNC and radiotherapy remarkably altered the proteome of the AEP. Antibacterial and acid-resistant proteins were decreased during radiotherapy. CLINICAL SIGNIFICANCE: Our results provide important information for designing more effective dental products for these patients, in addition to contributing to a better understanding of the differential protective roles of the AEP proteins during radiotherapy. Moreover, some proteins identified in the AEP after radiotherapy may serve as prognostic markers for survival of HNC patients.

The influence of fillers and protease inhibitors in experimental resins in the protein profile of the acquired pellicle formed in situ on enamel-resin specimens.

OBJECTIVE: This study evaluated the influence of the addition of fillers and/or protease inhibitors [(epigallocatechin gallate - EGCG) or (chlorhexidine - CHX)] in experimental resins in the protein profile of the acquired pellicle (AP) formed in situ on enamel-resin specimens. DESIGN: 324 samples of bovine enamel were prepared (6 × 6 × 2 mm). The center of each sample was added with one of the following experimental resins (Bis-GMA+TEGDMA): no filler, no inhibitor (NF-NI); filler no inhibitor (F-NI); no filler plus CHX (NF-CHX); filler plus CHX (F-CHX); no filler plus EGCG (NF-EGCG); filler plus EGCG (F-EGCG). Nine subjects used a removable jaw appliance (BISPM - Bauru in situ pellicle model) with 2 slabs from each group. The AP was formed for 120 min, in 9 days and collected with electrode filter paper soaked in 3% citric acid. The pellicles collected were processed for analysis by LC-ESI-MS/MS. RESULTS: A total of 140 proteins were found in the AP collected from all the substrates. Among them, 16 proteins were found in common in all the groups: 2 isoforms of Basic salivary proline-rich protein, Cystatin-S, Cystatin-AS, Cystatin-SN, Histatin-1, Ig alpha-1 chain C region, Lysozyme C, Mucin-7, Proline-rich protein 4, Protein S100-A9, Salivary acidic proline-rich phosphoprotein ½ and Statherin. Proteins with other functions, such as metabolism and transport, were also identified. CONCLUSION: The composition of the experimental resins influenced the protein profile of the AP. This opens a new avenue for the development of new materials able to guide for AP engineering, thus conferring protection to the adjacent teeth.

Effect of gels containing chlorhexidine or epigallocatechin-3-gallate on the protein composition of the acquired enamel pellicle.

OBJECTIVE: This study evaluated changes in protein profile of the acquired enamel pellicle (AEP) formed in vivo, after application of gels containing chlorhexidine or EGCG and further challenge with citric acid. DESIGN: AEP was formed in 9 volunteers for 2h and then treated with one of the following gels: placebo, 400µM EGCG or 0.012% chlorhexidine. A thin layer of gel was applied and after 1min the excess was removed. One hour after gel application, the AEP was collected from the buccal surface (upper and lower jaw) of one of the sides with filter paper dipped in 3% citric acid. On the other side, erosive challenge was performed through gentle application of 1% citric acid (pH 2.5) for 20s (using a pipette) followed by washing with deionized water. The AEP was collected as mentioned before. Proteomic analysis was performed through liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The MS/MS spectra obtained were compared with human protein databases (SWISS-PROT). Label-free quantitation was done using the PLGS software. RESULTS: In total, 223 proteins were identified. After treatment with EGCG and CHX gels, proteins with potential functions to protect against caries and erosion such as PRPs, calcium-bind proteins and Statherin were increased. When EGCG and CHX-treated AEPs were challenged with citric acid, there was increase in cystatins and Profilin-1. CONCLUSION: CHX- and EGCG-treated AEPs, submitted to challenge with citric acid or not, had remarkable changes in their proteomic profiles.

Carbon dioxide laser and bonding materials reduce enamel demineralization around orthodontic brackets.

Altering the structure of the enamel surface around the orthodontic bracket by reducing its content of carbonate and phosphate resulting from application of CO(2) laser may represent a more effective strategy in preventing caries in this region. This study aimed at determining whether irradiation with a CO(2) laser combined with fluoride-releasing bonding material could reduce enamel demineralization around orthodontic brackets subjected to cariogenic challenge. Ninety bovine enamel slabs were divided into five groups (n = 18): non-inoculated brain-heart infusion broth group, non-fluoride-releasing composite resin (NFRCR--control group), resin-modified glass ionomer cement (RMGIC), CO(2) laser + Transbond (L+NFRCR) and CO(2) laser + Fuji (L+RMGIC). Slabs were submitted to a 5-day microbiological caries model. The Streptococcus mutans biofilm formed on the slabs was biochemically and microbiologically analysed, and the enamel Knoop hardness number (KHN) around the brackets was determined. The data were analysed by ANOVA and Tukey tests (α = 0.05). Biochemical and microbiological analyses of the biofilm revealed no statistically significant differences among the groups. Lased groups presented the highest KHN means, which statistically differed from NFRCR; however, no difference was found between these lased groups. RMGIC did not differ from NFRCR which presented the lowest KHN mean. The CO(2) laser (λ = 10.6 µm; 10.0 J/cm(2) per pulse) use with or without F-bonding materials was effective in inhibiting demineralization around orthodontic brackets. However, no additional effect was found when the enamel was treated with the combination of CO(2) laser and an F-releasing material.

Oral rehabilitation of primary dentition affected by amelogenesis imperfecta: a case report.

AIM: The purpose of the case report was to describe the treatment of a 4(1/2)-year-old boy with amelogenesis imperfect (AI) in the primary dentition. BACKGROUND: AI is a hereditary condition that affects the development of enamel, causing quantity, structural, and compositional anomalies involving all dentitions. Consequently, the effects can extend to both the primary and secondary dentitions. CASE REPORT: A 4(1/2)-year-old boy was brought to the dental clinic complaining of tooth hypersensitivity during meals. The medical history and clinical examination were used to arrive at the diagnosis of amelogenesis imperfecta. The treatment was oral rehabilitation of the primary molars with stainless steel crowns and resin-filled celluloid forms of both maxillary and mandibular primary incisors and canines. Improvements in the patient's psychological behavior and the elimination of tooth sensitiveness were observed, and the reestablishment of a normal occlusion resulted in improved eating habits. The child was monitored in the Pediatric Dentistry Clinic at four-month intervals until the mixed dentition stage. SUMMARY: The oral rehabilitation of young children with AI is necessary to reestablish the stomatognathic system function, so important for a child's systemic health. An adequate medical history and a careful clinical examination were essential for a correct diagnosis. Treatment was rendered that was appropriate for the child's age and clinical/psychological characteristics. CLINICAL SIGNIFICANCE: Cost-effective restorative techniques involving stainless steel and composite-resin crowns are shown for the restoration of a young patient with amelogensis imperfecta.

Prosthetic rehabilitation in a four-year-old child with severe early childhood caries: a case report.

AIM: The purpose of this case report was to describe the oral rehabilitation of a 4-year-old girl presenting early childhood caries (ECC). BACKGROUND: ECC is highly prevalent in developing countries and its severity increases with age. This disease implies serious consequences for the development of the stomatognathic system and for the child's quality of life. As young children are usually anxious about dental treatment, their level of co-operation is limited, leading to a challenging situation. CASE REPORT: A 4-year-old girl was brought by her mother for dental treatment with the complaint of pain. The clinical examination revealed extensive carious coronary destructions. After preventive and curative measures, the oral rehabilitation was performed; it included the use of stainless steel crowns, resin filled celluloid crowns with previous cementation of glass post pins when necessary, an amalgam restoration, orthodontic treatment, and a partial removable prosthesis. The child has been monitored in the Pediatric Dentistry Clinic at 4-monthly intervals. SUMMARY: The oral rehabilitation was able to reestablish the oral health in the primary arches mutilated by early childhood caries. This is important for the establishment of an adequate mixed and permanent dentition, for proper facial and maxillary growth, and to the child's psychological and social development. CLINICAL SIGNIFICANCE: The full management, including preventive, psychological, and curative measures of a young child with severe ECC was found successful after 8 months of follow up. This result can encourage the clinicians to seek a cost-effective technique such as stainless steel crowns, resin filled celluloid crowns, and partial removable prosthesis to reestablish the oral functions and improve the child's psycho-social development.