Effects of stannous fluoride on eroded enamel permeability.

This study aimed to evaluate the effect in vitro of a single application of a stannous fluoride- (SnF2-) containing toothpaste on eroded enamel. Forty-eight teeth were subjected to three acid treatments: 15% hydrochloric acid for 120 s (HA group); 1% citric acid (pH=4) for 180 s (CA group); 37% phosphoric acid for 30 s (PA group). They were brushed with an electric toothbrush with pressure control and 1 g of SnF2 (1100 ppm) toothpaste for 2 min. Polyether replicas of buccal enamel surfaces were obtained at baseline, after acid exposure and after brushing, gold sputtered and inspected by SEM for fluid droplets presence. Hydrochloric and citric acid treatments increased enamel permeability while, on the contrary, phosphoric acid reduced enamel fluid release. SnF2 application of ameliorated acid induced permeability in citric and hydrochloric treated samples. Permeability in phosphoric treated enamel was unchanged after topical application of SnF2. Our data show specific acid-dependent effects on enamel permeability and demonstrate that SnF2 application can reverse acid-induced permeability.

In vitro effects of fluoride-based and desensitizing toothpastes on dentine permeability.

This study aims to evaluate the effectiveness in reducing dentine permeability of three different toothpastes comparing with a sodium fluoride one. Dentine permeability was measured by a fluid filtration system. Dentin discs were randomized in four experimental groups and treated with different commercial toothpastes, as it follows. Group A: Sensodyne® Rapid, with strontium acetate; group B: Elmex Sensitive ProfessionalTM, with arginine and 450 ppm monofluoro-phosphate; group C: Colgate Total Advanced®, with 1450 ppm NaF; group D: AZ Pro-Expert®, with 1100 ppm SnF2. After brushing specimens of each groups were assigned to two subgroups and: 1) stored in artificial saliva (2 h) and treated with 6% citric acid for 1 min; 2) stored in artificial saliva for 24 h. SEM analysis was performed to investigate dentinal tubules occlusion of acid treated and stored in artificial saliva samples. Dentin permeability proved affected by dentifrice treatments. The toothpastes specifically formulated for hypersensitivity showed significant effects concerning decrease of dentine permeability. SEM observations demonstrated the presence of dentifrice particles on dentin surface and inside dentin tubules. Stannous fluoride treated samples exhibited the greater tubules occlusion.

Primary enamel permeability: a SEM evaluation in vivo.

AIM: The aim of this study was to evaluate in vivo the occurrence of outward fluid flow on primary tooth sound enamel surface. MATERIALS AND METHODS: Sixty primary upper canines from preadolescent patients (mean age 8.0±1.9) and 24 retained primary upper canines from adult subjects (mean age 35.0±1.8) were analysed. The enamel surface was gently polished and air dried for 10 s. An impression was immediately obtained by vinyl polyxiloxane. Replicas were then obtained by polyether impression material, gold coated and inspected under SEM. The hydrophobic vinyl polyxiloxane material enabled to obtain in situ a morphological image of the presence of droplets, most likely resulting from outward fluids flow through outer enamel. For each sample three different representative areas of 5µ² in the cervical, medium and incisal third were examined and droplets presence values was recorded. All data were analysed by by Fisher's exact test. RESULTS: Primary enamel showed a substantial permeability expressed as droplets discharge on its surface. Droplets distribution covered, without any specific localisation, the entire enamel surface in all the samples. No signs of post-eruptive maturation with changes in droplets distribution were observed in samples from adult subjects. No statistically significant differences (P = 0.955) were noted in the percentage distribution of enamel area covered with droplets among the two group studied. CONCLUSION: SEM evaluation of droplets distribution on enamel surface indicated a substantial enamel permeability in primary teeth, accordingly with histological features, without changes during aging. A relationship between enamel permeability, caries susceptibility and bonding procedures effectiveness could be hypothesised.

Coronoid hyperplasia. A case report.

Coronoid hyperplasia is a rare condition which is macroscopically characterized by an increase in the dimensions of the coronoid process resulting from an abnormal bony elongation of histologically normal bone. Unilateral cases are more frequent than bilateral ones and can recognize a number of etiological factors, such as exostoses, osteochondroma, traumatic events, inflammatory reactions, neoplasia and manifestations secondary to other pathologies. Etiopathogenesis of bilateral forms has not yet been clarified: in the literature hints to both developmental and endocrine abnormalities are present, and a familiar pattern of inheritance has been evidenced. The poor specificity of signs and symptoms associated with coronoid hyperplasia, which are similar to those of other more frequent forms of temporomandibular disorders, present some problems of differential diagnosis. An accurate assessment must be based on a clinical and anamnestical approach aiming at the identification of pathognomonic clinical symptoms. Considering its limits (such as the possible presence of artefacts and image distortions), orthopantomography has a poor diagnostic usefulness. In this case, magnetic resonance (MR) allowed to evaluate disk-condyle relationship, but it could be also useful to evaluate post-operative complications. In the case of coronoid hyperplasia, the computed tomography (CT) is fundamental for a correct differential diagnosis. CT also allows surgical planning due to its accuracy to detect coronoid process volume and morphology. The present case report is an example of the need for a correct differential diagnosis between the different types of temporomandibular disorders, and it also lends support to the importance of requesting modern imaging techniques during the diagnostic process of the rare or complex cases.

Diagnosis of temporomandibular disorders according to RDC/TMD axis I findings, a multicenter Italian study.

AIM: The aim of the present study was to evaluate the prevalence of the different Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) Axis I types of temporomandibular disorders (TMD) in a population of subjects seeking for TMD treatment at 2 University Departments in Italy and to compare it with data from similar studies in the literature, in order to assess the usefulness of the RDC/TMD classification system as a tool for epidemiological data gathering and multicenter and cross-cultural comparison. METHODS: A total of 210 consecutive patients seeking for TMD treatment at the Section of Prosthetic Dentistry, Department of Neuroscience, University of Pisa, Italy, and 109 consecutive patients seeking treatment at the Section of Prosthetic Dentistry and Temporo-mandibular Disorders, University of Pavia, Italy, were assessed using RDC/TMD. RESULTS: Only 181 of the patients referring to the University of Pisa and 104 of those referring to the University of Pavia satisfied the criteria for inclusion. Findings from the 2 study populations were very similar. Mean age of the patients was 40 years, with a female:male ratio of 3.5:1 (222 females, 77.9%; 63 males, 22.1%). The prevalence of RDC/TMD Axis I diagnoses was 50.2% (143/285) for Group I disorders (muscle disorders), 38.6% (110/285) for Group II disorders (disc displacement), and 50.2% (143/285) for Group III disorders (arthralgia, osteoarthritis, osteoarthrosis). CONCLUSION: Results from the present investigation have confirmed the usefulness of the RDC/TMD classification system for research purposes and for data gathering in cross-cultural and multicenter comparisons.