Dentine desensitization induced by prophylactic and air-polishing procedures: An in vitro dentine permeability and confocal microscopy study

Objectives

The exposure of dentinal tubules causes fluid movement and dentinal hypersensitivity. This study aimed at evaluating the dentine permeability after prophylactic measures performed on exposed dentine after immersion in artificial saliva and citric acid challenge. Confocal microscopy was performed to evaluate the percentage of occluded tubules (OCT%) and the changes in dentine morphology.

Methods

Prophy-powders and pastes were tested in this study. An oxalic acid liner was used as a positive control. Dentine discs from human third molars were treated with each material and the dentine permeability was evaluated using a fluid filtration system working at 20 cm H₂O. Artificial saliva and citric acid were used for the determination of changes in dentine permeability. The percentage of tubule occlusion capability (OCT%) was evaluated using confocal microscopy.

Results

All the products used in this study were able to significantly reduce the dentine permeability of acid-etched specimens. The use of the bioactive glass and sodium bicarbonate showed the highest values in dentine permeability reduction. However, the air-polishing procedures performed with Sylc bioactive glass powder created a dentine surface resistant to citric acid attack.

Conclusion

Bioactive glass is suitable for treatment of dentinal hypersensitivity by creating a dentine surface resistant to citric acid attack.     

Effect of a pulsed CO2 laser and fluoride on the prevention of enamel and dentine erosion

Objective

The hypotheses of this study was that pulsed CO₂ laser (λ = 10.6 μm) treatment in combination (or not) with previous fluoride gel application could increase the resistance of enamel and dentine to erosion, throughout successive erosive challenges.

Design

Thirty-two bovine specimens of enamel and of root dentine were flattened, polished and randomly assigned to the following treatments (n = 8): fluoride (F), laser (L), fluoride + laser (FL) or no treatment as negative control (C). The treated specimens were submitted to demineralization (0.3% citric acid, pH 2.45, for 5 min) and remineralization (artificial saliva, for 60 min) cycles, three times a day, for 3 days. Dental surface loss as well as the concentration of calcium, phosphorus and fluoride in the demineralizing solutions were determined after each cycling day. Enamel and dentine were analysed separately using repeated measures ANOVA for ranks (α = 0.05).

Results

The association between fluoride and laser (FL) resulted in the lowest enamel and dentine surface loss values throughout the cycles, differing significantly from the control group. No clear benefit of FL over the F or L treatments was observed. There was a non-significant trend (p > 0.05) for FL to release less calcium, phosphorus and fluoride into the demineralizing solutions when compared to the other groups.

Conclusions

Pulsed CO₂ laser (λ = 10.6 μm) alone was not able to prevent enamel or dentine surface losses due to erosion. Laser treatment in combination with fluoride showed some protection, but the effect does not appear to be synergistic.     

Prevenzione della carie: ruolo dell’alimentazione e della fluoroprofilassi

Objectives

Point out the two main factors of caries prevention nowadays: a not cariogenic diet and fluoride.

Materials and methods

A literature revision was performed using Pubmed and Medline databases and the Cochrane Library.

Results and conclusions

To prevent tooth decay effectively the collaboration with patient is necessary. The patient is required to make life-styles modifications and adopt good habits as far as nutrition and hygiene are concerned. Preventive evidence-based strategies tailored to the caries risk status of each patient must be implemented.     

Fluoride release and anti-erosive effects of dentifrices containing PVM/MA copolymers

Objective

To evaluate fluoride release from dentine discs and study the effects of dentine tubule occlusion and erosion prevention of dentifrices containing fluoride and PVM/MA copolymers in a cycling erosive challenge model.

Methods

Human dentine discs, 15 in each group, were eroded by 1.0% citric acid and treated by ProNamel^® (PRN, 1450 ppm fluoride), Colgate^® Total Sensitive (CTS, 1100 ppm fluoride), a prototype dentifrice containing 5000 ppm fluoride and 2% PVM/MA copolymers (PVD) and distilled water (control). Fluoride release from each dentine disc was evaluated every 2 h in a 12-h period. For cycling erosive challenges, dentine discs were treated by dentifrice slurries twice daily, followed by immersion in saliva and erosive challenges by orange juice. Dentine discs were stored in saliva between treatment cycles and the cycling erosive challenges were repeated for 15 days. On days 5, 10, and 15, size of dentine tubule openings and level of dentine tubule occlusion were evaluated with a 3D scanning microscope.

Results

PVD released more fluorides than other dentifrices in a 12-h period (p < 0.05). CTS released more fluorides than PRN at 2, 4, 6, and 8 h following a single application (p < 0.05). The size of the dentine tubules was smaller and the number of occluded dentine tubules was greater in the CTS and PVD groups than those in the control and PRN groups on day 15 of the erosive challenges.

Conclusion

Bioadhesive PVM/MA copolymers facilitate fluoride retention and release from dentine discs, and promote dentine tubule occlusion and erosion prevention when combined with hydrated silica particles.     

Dentine caries inhibition through CO(2) laser (10.6μm) irradiation and fluoride application, in vitro

Objective

The purpose of the study was to investigate whether dentine irradiation with a pulsed CO₂ laser (10.6 μm) emitting pulses of 10 ms is capable of reducing dentine calcium and phosphorus losses in an artificial caries model.

Design

The 90 dentine slabs obtained from bovine teeth were randomly divided into six groups (n = 15): negative control group (GC); positive control group, treated with fluoride 1.23% (GF); and laser groups irradiated with 8 J/cm² (L8); irradiated as in L8 + fluoride 1.23% (L8F); irradiated with 11 J/cm² (L11); irradiated as in L11 + fluoride 1.23% (L11F). After laser irradiation the samples were submitted to a pH-cycling model for 9 days. The calcium and phosphorous contents in the de- and remineralization solutions were measured by means of inductively coupled plasma optical emission spectrometer – ICP-OES. Additionally intrapulpal temperature measurements were performed. The obtained data were analysed by means of ANOVA and Tukey's test (α = 0.05).

Results

In the demineralization solutions the groups L11F and GF presented significantly lower means of calcium and phosphorous losses than the control group; and in L11F means were significantly lower than in the fluoride group. Both irradiation parameters tested caused intrapulpal temperature increase below 2 °C.

Conclusion

It can be concluded that under the conditions of this study, CO₂ laser irradiation (10.6 μm) with 11 J/cm² (540 mJ and 10 Hz) of fluoride treated dentine surfaces decreases the loss of calcium and phosphorous in the demineralization process and does not cause excessive temperature increase inside the pulp chamber.     

Comparison of remineralization effect of three topical fluoride regimens on enamel initial carious lesions

Objectives

Some studies have been conducted to evaluate the effect of different topical fluoride regimens on the remineralization of initial carious lesions. This study was conducted to compare the effects of 3 topical fluoride treatments on the surface microhardness, fluoride uptake, and fluorescence lesion area in enamel.

Methods

Forty-eight bovine teeth were demineralized and subjected to one of the following treatments: (1) no treatment (control), (2) iontophoresis using 2% sodium fluoride solution, (3) 1.23% acidulated phosphate fluoride gel application, and (4) 5% sodium fluoride varnish application. Six persons continuously wore a mandibular removable appliance mounted with eight treated bovine teeth orally for 4 weeks, except while eating, sleeping, and brushing. Microhardness of enamel surfaces was measured using a digital microhardness tester. The fluoride concentration was analyzed using a fluoride electrode, and the fluorescence lesion area was calculated by confocal laser scanning microscopy.

Results

No significant differences in the microhardness were observed in response to the 3 fluoride regimens. The highest level of fluoride was observed in the APF gel group. APF gel group also showed significantly reduced fluorescence lesion areas compared to those of the control group.

Conclusions

The fluoride regimens showed no difference in surface microhardness; although APF gel showed the best effects in terms of fluoride uptake and decrease in the fluorescence lesion area, its effects were not significantly different from those of fluoride varnish.     

Il management dell’ipersensibilità dentinale: dalla ricerca alla clinica

Objectives

The aim of this paper is to present an overview of the current state of knowledge about dentin hypersensitivity, in terms of epidemiology, aetiology/risk factors, pain mechanisms, diagnosis and management. Available products for treatment of dentin hypersensitivity are described and scientific and clinical research validating their efficacy is reviewed.

Materials and methods

Original papers, reviews and guidelines on the subject, published both in English and in Italian from 2009 to 2013, were retrieved from the Medline/Pubmed database. Additional publications were obtained by searching the reference list of the retrieved works.

Results and conclusions

The management of dentin hypersensitivity is based on the control of causal factors and on the application, at-home or in-office, of various products aimed to occlude patent tubules. In vitro methods suffer from some limitations in mimicking “real-life” individual behaviours and ecological variables in the oral environment, therefore randomized and controlled clinical trials are considered the gold standard to evaluate the efficacy of these products. The arginine-calcium carbonate complex has proved to be efficacious in providing instant and long-lasting relief. Further randomized and controlled clinical studies are needed to confirm the results of amorphous sodium calcium phosphosilicate and strontium acetate.     

CO2, ER:YAG AND ND:YAG LASERS IN ENDODONTIC SURGERY

Objectives:

CO₂, Er:YAG and Nd:YAG lasers have been used in endodontic surgery. This in vitro study evaluated 1% Rhodamine B dye penetration using computer-assisted morphometry (ImageTool Software®) of 108 endodontically treated human permanent canines.

Material and methods:

Teeth were divided into 9 groups according to the technique used: A: 90-degree apicoectomy with bur, root-end cavity preparation with ultrasound and filled with MTA; B: 90-degree apicoectomy with bur, root-end cavity prepared with ultrasound and filled with MTA, and treatment of apical surface with CO₂ laser (1 W, CW/CW); C: 90-degree apicoectomy with bur, and treatment of apical surface with Nd:YAG laser (150 mJ, 10 Hz); D: 90-degree apicoectomy with bur, and treatment of apical surface with CO₂ laser (1 W, CW/CW); E: apicoectomy with Er:YAG laser (400 mJ, 10 Hz), root-end cavity prepared with ultrasound and filled with MTA; F: apicoectomy with Er:YAG laser (400 mJ, 10 Hz) and treatment of apical surface with Nd:YAG laser (150 mJ, 10Hz); G: apicoectomy with CO₂ laser (5W, CW/SP), root-end cavity prepared with ultrasound and filled with MTA; H: irradiation of apical end with CO₂ laser (1 W, CW/CW); I: irradiation of apical end with Nd:YAG laser (150 mJ, 10 Hz).

Results:

Dye penetration was found in all specimens at different rates, the lowest penetration occurring in groups C (16.20%), B (17.24%) and F (17.84%).

Conclusions:

Groups B, C and F represent the best technical sequences to perform endodontic surgery.     

Clinical evaluation of Er,Cr:YSGG and GaAlAs laser therapy for treating dentine hypersensitivity: A randomized controlled clinical trial

Objective

The advent of dental lasers has raised another possible treatment option for dentine hypersensitivity (DH) and has become a research interest in the last decades. The aim of this randomized, controlled, double-blind, split mouth, clinical study was to evaluate and compare the desensitizing effects of erbium, chromium-doped:yttrium, scandium, gallium and garnet (Er,Cr:YSGG) to galium-aluminium-arsenide (GaAlAs) laser on DH.

Methods

Fifty-one patients participated in this study for a total of 174 teeth. DH was assessed for all groups with a visual analog scale. For each patient, the teeth were randomized to three groups. In the diode laser group, sensitive teeth were irradiated with the GaAlAs laser at 8.5 J/cm² energy density. In the Er,Cr:YSGG laser group, sensitive teeth were irradiated with Er,Cr:YSGG laser in the hard tissue mode using a none-contact probe at an energy level of 0.25 W and repetition rate of 20 Hz, 0% water and 10% air. In the control group no treatment was performed. Treatment time was 60 s for GaAlAs laser and 30 s for Er,Cr:YSGG laser.

Results

When compared with the control group and baseline data, in both laser groups, laser irradiation provided a desensitizing effect immediately after treatment and this effect was maintained throughout the study (p < 0.05). No significant differences between Er,Cr:YSGG and GaAlAs laser groups were found at any follow-up examination (p > 0.05).

Conclusion

Based on these findings, it may be concluded that both Er,Cr:YSGG and GaAlAs lasers were effective in the treatment of DH following a single application.     

An in situ study investigating dentine tubule occlusion of dentifrices following acid challenge

Objectives

To investigate the dentine occlusion and acid resistance of dentifrices developed to treat dentine hypersensitivity.

Methods

This was a single centre, single blind, randomised, split mouth, four treatments, two period crossover, in situ study in healthy subjects. Subjects wore buccal intra-oral appliances each fitted with four dentine samples over four consecutive days with one study product applied per appliance; 8% strontium acetate in silica base, 1040 ppm sodium fluoride (Sensodyne^® Rapid Relief), 8% arginine, calcium carbonate, 1450 ppm sodium monofluorophosphate (Colgate Sensitive Pro-Relief^®), 1450 ppm sodium fluoride (control paste) and water. On days 3 and 4, two agitated grapefruit juice challenges (ex vivo) occurred for 1 min. At the end of each treatment day 1 dentine sample was removed from each appliance for scanning electron microscopy (SEM). The extent of tubule occlusion was measured using an examiner-based visual scoring index (three trained examiners).

Results

In total, 28 subjects ((12 males and 16 females with a mean age of 34.7 years (SD 8.41 years)) completed the study. On day 2, both test dentifrices demonstrated significantly better dentine tubule occlusion than water (p < 0.0001) and control paste (8% strontium p = 0.0003 and 8% arginine p = 0.0019). After 3 and 4 days of twice daily brushing with acid challenges on days 3 and 4 the strontium-based dentifrice demonstrated significantly better dentine occlusion than all other treatments (p < 0.0001).

Conclusions

Strontium acetate and arginine-based dentifrice result in statistically significant dentine tubular occlusion compared to controls, but the arginine-based dentifrice is more susceptible to acid challenge.

Clinical significance

Erosive beverages are an important aetiology in DH by exposing dentine tubules. Their consumption has increased significantly over the past decade in the UK. This 4-day in situ study investigated the properties of commercially available dentifrices designed to occlude dentine tubules and their resistance to an agitated acid challenge.     

The combined use of Er,Cr:YSGG laser and fluoride to prevent root dentin demineralization

The use of erbium lasers to prevent caries in enamel has shown positive results. However, it is not known if Er,Cr:YSGG laser can also be used to increase acid resistance of root dentine, which is another dental tissue susceptible to the action of cariogenic bacteria.

Objective

To analyze the effects of the Er,Cr:YSGG laser (λ=2.78 μm, 20 Hz) irradiation associated with 2% neutral sodium fluoride (NaF) to prevent root dentin demineralization.

Material and Methods

One hundred human root dentin samples were divided into 10 groups (G) and treated as follows: G1: no treatment; G2: NaF; G3: laser (4.64 J/cm²) with water cooling (WC=5.4 mL/min); G4: laser (4.64 J/cm²) without WC; G5: laser (8.92 J/cm²) with WC; G6: laser (8.92 J/cm²) without WC; G7: laser (4.64 J/cm²) with WC and NaF; G8: laser (4.64 J/cm²) without WC and NaF; G9: laser (8.92 J/cm²) with WC and NaF; G10: laser (8.92 J/cm²) without WC and NaF. The NaF gel was applied alone or after 4 min of irradiation. After 14 days of acid challenge, the samples were sectioned and the Knoop microhardness (KHN) test was done at different depths (30, 60, 90 and 120 μm) from the outer dentin surface. Data were analyzed by one-way ANOVA and Fisher''s test (α=5%).

Results

The results showed that G8 and G10 presented higher KHN than the G1 for the depths of 30 and 60 μm, indicating an increase of the acid resistance of the dentin in up to 35% (p<0.05).

Conclusions

The use of Er,Cr:YSGG laser irradiation at 4.64 J/ cm² and 8.92 J/cm² without water cooling and associated with 2% NaF can increase the acid resistance of human root dentin.     

Valutazione della collaborazione del paziente in funzione dell’età: metodiche preventodontiche

Objectives

The aim of this work is to evaluate if patients of different sex and ages learn oral preventive methods in different ways.

Materials and methods

One-hundred and twenty patients in preventodontic iter of different sex and age were included in the study.

Results

Remarkable results were obtained regarding both the effective reduction of bacterial oral flora and patient's compliance and learning, especially in the group of patients older than 10 years.

Conclusions

Patient instruction and motivation allow to obtain optimal results in particular in patients aged more than 10 years.     

Prevention of dentine erosion by brushing with anti-erosive toothpastes

Objective

This in vitro study aimed to investigate the preventive effect of brushing with anti-erosive toothpastes compared to a conventional fluoride toothpaste on dentine erosion.

Materials and methods

Bovine dentine specimens (n = 12 per subgroup) were eroded in an artificial mouth (6 days, 6 × 30 s/day) using either citric acid (pH:2.5) or a hydrochloric acid/pepsin solution (pH:1.6), simulating extrinsic or intrinsic erosive conditions, respectively. In between, the specimens were rinsed with artificial saliva. Twice daily, the specimens were brushed for 15 s in an automatic brushing machine at 2.5 N with a conventional fluoride toothpaste slurry (elmex, AmF) or toothpaste slurries with anti-erosive formulations: Apacare (NaF/1% nHAP), Biorepair (ZnCO₃-HAP), Chitodent (Chitosan), elmex Erosionsschutz (NaF/AmF/SnCl₂/Chitosan), mirasensitive hap (NaF/30% HAP), Sensodyne Proschmelz (NaF/KNO₃). Unbrushed specimens served as control. Dentine loss was measured profilometrically and statistically analysed using two-way and one-way ANOVA followed by Scheffe‘s post hoc tests. RDA-values of all toothpastes were determined, and linear mixed models were applied to analyse the influence of toothpaste abrasivity on dentine wear (p < 0.05).

Results

Dentine erosion of unbrushed specimens amounted to 5.1 ± 1.0 μm (extrinsic conditions) and 12.9 ± 1.4 μm (intrinsic conditions). All toothpastes significantly reduced dentine erosion by 24–67% (extrinsic conditions) and 21–40% (intrinsic conditions). Biorepair was least effective, while all other toothpastes were not significantly different from each other. Linear mixed models did not show a significant effect of the RDA-value of the respective toothpaste on dentine loss.

Conclusion

Toothpastes with anti-erosive formulations reduced dentine erosion, especially under simulated extrinsic erosive conditions, but were not superior to a conventional fluoride toothpaste.     

Effect of a 10% carbamide peroxide on wear resistance of enamel and dentine: In situ study

Objectives

This triple-blind, 2 × 2 crossover in situ study, was undertaken to verify whether the wear resistance of enamel and root dentine would be affected by bleaching with a 10% carbamide peroxide agent and a placebo agent.

Methods

Thirty slabs of each substrate (2 mm × 3 mm × 2 mm) were selected for each phase, after flattening and polishing procedures and microhardness test. After a 7-day lead-in period, one specimen of each substrate was randomly bonded on the facial surface of each one of 30 subject's upper second premolars. The volunteers received instructions on how to perform toothbrushing and application of gel in the tray. Fifteen volunteers bleached their maxillary arch with a 10% carbamide peroxide bleaching agent for a 2-week period, while the remainders used a placebo agent. After a 1-week washout period, a new set of enamel and root dentine slabs were bonded to the premolars and volunteers were crossed over to the alternate agent for 14 days. The resistance of enamel and root dentine to wear following bleaching, toothbrushing and intraoral exposure was measured with a profilometer, using reference areas.

Results

For enamel, ANOVA did not demonstrate significant difference between wear provided by placebo and bleaching agent (p = 0.3713), but higher wear depth was observed for bleached root dentine (p = 0.0346).

Conclusions

While overnight bleaching caused no alteration in wear resistance of enamel, root dentine showed increased tissue loss.     

Effectiveness of arginine-containing toothpastes in treating dentine hypersensitivity: A systematic review

Objectives

To evaluate by way of a systematic review the effectiveness of arginine-containing desensitising toothpastes in comparison to control agents in reducing dentine hypersensitivity.

Data sources

Electronic databases were searched including: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, LILACS (30/03/2012). Reference lists of eligible studies and systematic reviews were cross-checked in an attempt to identify additional studies. Strategies to identify grey literature were employed.

Study selection inclusion criteria

Controlled Clinical Trials (CCTs) and Randomised Controlled Trials (RCTs) comparing arginine-containing desensitising toothpastes to non-arginine-containing control toothpastes.Two review authors independently screened the titles and abstracts of studies identified. Data collection forms were completed for included studies.

Outcomes

Changes in sensitivity to tactile and air-blast stimuli. A subjective assessment of sensitivity was also sought.

Conclusion

Data identified indicates a potential role for arginine-containing toothpastes in managing dentine hypersensitivity. However, this conclusion is based on small sample sizes and the studies identified did not follow patients up in the medium to long term. The authors recommend that there is a need for well-designed RCTs to be conducted prior to any definitive recommendations being made.

Clinical significance

Dentine hypersensitivity is a common condition. Its multi-factorial aetiology has led to several treatment modalities being advocated. The continued introduction of new desensitising agents suggests that no product has yet proven ultimately successful. Arginine-containing toothpastes have recently been introduced, this article systematically reviews the evidence relating to their effectiveness.     

Effect of sodium,amine and stannous fluoride at the same concentration and different pH on in vitro erosion

Objective

This study aimed to compare the effects 0.5% and 1% sodium, amine and stannous fluoride at different pH on enamel erosion in vitro.

Methods

Bovine enamel samples were submitted to a cyclic de- and remineralisation for 3 days. Each day, the samples were exposed for 120 min to pooled human saliva and subsequently treated with one of the fluoride solutions for 3 min: amine fluoride (AmF, 0.5% and 1% F⁻), sodium fluoride (NaF, 0.5% and 1% F⁻), each at pH 3.9 and 7.0, and stannous fluoride (SnF₂, 0.5% and 1% F⁻), at pH: 3.9. Additionally, two groups were treated with fluoride-free placebo solutions (pH: 3.9 and 7.0) and one group served as control (no fluoridation). Ten specimens each group were inserted in a so-called artificial mouth and eroded six times daily with hydrochloric acid (pH 2.6) for 90 s each intermitted by exposure to artificial saliva (1 h). After 3 days, enamel loss was analyzed profilometrically and evaluated statistically by ANOVA.

Results

Only the acidic 0.5% and 1% SnF₂ and 1% AmF solutions were able to reduce erosive enamel loss significantly, while all other solutions and placebos did not differ significantly from the control. Between the acidic SnF₂ and the 1% AmF solutions no significant differences could be detected.

Conclusion

At the same concentrations, acidic SnF₂ and AmF may be more effective than NaF to protect enamel against erosion.     

Fattori prognostici dell’eruzione dell’incisivo permanente incluso

Objectives

The aim of the present review was to identify factors influencing the eruption of impacted permanent incisors.

Materials and methods

Mitchell and Bennet evaluated the distance of the unerupted permanent tooth from the occlusal plane and classified it as: near (vertical displacement: crown of the impacted tooth is at the level of the coronal third of the root of the adjacent tooth; horizontal displacement: > half the width of the tooth itself); mid (vertical: the tooth is at the level of the middle third of the root of the adjacent tooth; horizontal displacement: > ½ but < 1 times the width of the tooth); far, greater displacement. Smailiene et al. analyzed the vertical position of impacted permanent incisors in relation to the contralateral erupted central incisor. They defined three positions: v1, the crown is at the level of the gingival third of the root of the adjacent permanent incisor; v2, the crown is at the level of middle third of the root; v3, the crown is at the level of apical third of the root. Bryan et al. estimated inclination of the unerupted tooth calculated as the angle between its long axis and the mid-sagittal plane.

Results and conclusions

These methods are easy to perform and effective for predicting the spontaneous eruption of malposed incisors. The vertical position of the tooth and the angle between its long axis and the mid-sagittal plane appear to be important factors for predicting eruption.     

Biomimetic mineralisation of phosphorylated dentine by CPP-ACP

Objectives

Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) has the potential to induce the biomimetic mineralisation of dentine collagen fibrils. This study aimed to demonstrate in vitro the ability of CPP-ACP to form apatite crystals on phosphorylated dentine collagen fibrils.

Methods

Dentine slices with a 2-mm thickness were prepared from sound human third molars. The slices were etched with phosphoric acid to expose the collagen fibres. Sodium trimetaphosphate was then used to phosphorylate the exposed collagen fibres. CPP-ACP paste was topically applied to the surface of the phosphorylated slices, which were then immersed in a metastable calcium phosphate remineralising solution and incubated at 37 °C for 10 days. The CPP-ACP paste and the remineralising solution were replaced every two days. Phosphorylated dentine slices without a CPP-ACP application and non-phosphorylated dentine slices with a CPP-ACP application were prepared and used for comparison. The slices were examined using scanning electron microscope (SEM), diffuse reflectance-Fourier transform infrared spectroscopy (DR-FTIR) and X-ray diffraction (XRD).

Results

The SEM results revealed the presence of intrafibrillar and interfibrillar crystal nucleation and growth along the phosphorylated dentine collagen fibres. The DR-FTIR and XRD confirmed that the crystals were hydroxyapatite. No apatite crystal nucleation and growth were observed in either the slices that had no non-phosphorylation or those without CPP-ACP application.

Conclusions

CPP-ACP can induce the biomimetic mineralisation of dentine through apatite formation along and between the phosphorylated dentine collagen fibres.

Clinical significance

The in vitro study imitated the application of CPP-ACP to exposed dentine tooth surfaces in the mouth. This could lead to the development of a new therapeutic technique for the treatment of tooth hypersensitivity.     

La figura professionale dell’igienista dentale nell’ambito della sanità pubblica

Objectives

The project aims to analyze the feasibility of an oral hygiene service provided by a graduated dental hygienist in a public medical facility, oriented towards primary and secondary oral prevention services of social utility, as an alternative to what it is offered by the private sector.

Methods

In order to carry out this project, all necessary data and requirements have been identified with reference to the current regulation, the public health services resources and the expectations of the final user. The organization of the oral hygiene service has been analyzed with particular attention to the type of service, the operative methods, the responsibilities and competences. The resources through which oral hygiene services are efficiently and effectively provided have also been analyzed.

Results

The author presents data related to cost analysis, price of each service provided to the patient and to the assigned resources in relation to services provided in a public medical facility by graduated dental hygienists.

Conclusions

Although the insertion of dental hygienists represents a cost for the medical facility, through the calculation made to evaluate the different modalities to offer a private service or a reduced charge, it is possible to regulate the relationship between the dental hygienist and the medical facility with benefits for both and patients. The author therefore underlines the suitability and feasibility of the project.     

EDTA or H3PO4/NaOCl dentine treatments may increase hybrid layers’ resistance to degradation: A microtensile bond strength and confocal-micropermeability study

Objectives

The aim of this study was to reduce hybrid layer degradation created with simplified dentine adhesives by using two different methods to condition the dentine surface.

Methods

A smear-layer was created on flat dentine surfaces from extracted human third molars with a 180-grit/SiC-paper. Dentine specimens were conditioned before bonding with the following procedures: 37% H₃PO₄; H₃PO₄/0.5% NaOCl; 0.1 M EDTA; 0.1 M EDTA/0.5% NaOCl. Two etch-and-rinse adhesives: (Scotchbond 1XT or Optibond Solo Plus) were applied and light-cured. Composite build-ups were constructed. The bonded teeth were sectioned into beams, stored in distilled water (24 h) or 12% NaOCl solution (90 min) and finally tested for microtensile bond strengths (μTBS). Additional dentine surfaces were conditioned and bonded as previously described. They were prepared for a pulpal-micropermeability confocal microscopy study and finally observed using confocal microscopy.

Results

μTBS results revealed that both adhesives gave high bond strengths to acid-etched dentine before, but not after a 12% NaOCl challenge. Bonds made to acid-etched or EDTA-treated dentine plus dilute NaOCl, gave high μTBS that resisted 12% NaOCl treatment, as did EDTA-treated dentine alone. A confocal micropermeability investigation showed very high micropermeability within interfaces of the H₃PO₄, etched specimens. The lowest micropermeability was observed in H₃PO₄ + 0.5% NaOCl and 0.1 M EDTA groups.

Conclusions

The use of dilute NaOCl (0.5%) after acid-etching, or the conditioning of dentine smear layers with 0.1 M EDTA (pH 7.4) produced less porous resin–dentine interfaces. These dentine-conditioning procedures improve the resistance of the resin–dentine bond sites to chemical degradation (12% NaOCl) and may result in more durable resin–dentine bonds.