Effects of copper vapor laser irradiation (λ = 510.6 nm) on the enamel and dentine of human teeth: An ultra-structural morphologic study

Objective: A morphological and ultra-structural study of copper vapor laser (λ = 510.6 nm) effects on enamel and dentine was performed to show the effects of this radiation. Methods: A total of 15 human molars were cut in half; 15 pieces were separated for irradiation on enamel and 15 for dentine. These two groups were further divided into five experimental groups, including a control group, comprised of three half-sections each, irradiated by a CVL laser with a power of 7 W, a repetition rate of 15,000 pulses/sec and exposed at 500, 600, and 800 msec and 1 sec irradiation times with a 5-sec interval between irradiations. Results: In an ultra-structural SEM exam, we observed that on the enamel surfaces irradiated for 1 sec there was morphological alteration that consisted of catering, flaking, and melting on the surfaces. There was no alteration for the other exposure times. On the dentine teeth irradiated for 1 sec, we observed an evident ultra-structural alteration of melted tissue and loss of morphological characteristics. In the dentine group irradiated by 800 msec, we observed ablation and a partial loss of morphological characteristics. In the dentine groups irradiated by 500 and 600 msec, no alteration was observed. Conclusions: The results showed that irradiation with CVL promoted morphologic changes in the enamel as well as in the dentine and demonstrated a need for future studies in order to establish a safe protocol for further use in the odontological practice.

Effect of polymerization methods and thermal cycling on color stability of acrylic resin denture teeth

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of intracanal dressings on repair and apical bridging of teeth with incomplete root formation

Periapical repair and apical bridging were studied in dog's teeth with incomplete root formation and induced chronic periapical lesions treated with different dressings. A total of 75 root canals from the upper and lower premolars of 4 dogs approximately 6 months of age were chemo-mechanically prepared and filled with the following dressings: antibacterial dressing consisting of a calcium hydroxide+camphorated p-monochlorophenol paste applied for 7 days and followed by monthly renewed calcium hydroxide paste as temporary dressing at 30, 60 and 90 days (Group A); antibacterial dressing consisting of camphorated p-monochlorophenol alone for 7 days, followed by temporary dressing with calcium hydroxide paste renewed at 30, 60 and 90 days (Group B). A control group (Group C) received no dressings. Ninety days after the last calcium hydroxide paste (Groups A, B) and after the last irrigation/aspiration (Group C), the animals were killed, the maxillae and mandibles were removed, and the material submitted to routine histological processing and examination. Both root canal dressings, were of fundamental importance for apical repair and bridging. The apical bridging was predominantly complete in Group A, incomplete in Group B, and absent in Group C. The calcium hydroxide+camphorated p-monochlorophenol combination gave better results than camphorated p-monochlorophenol alone.

Longitudinal evaluation of the structural integrity of teeth affected by molar incisor hypomineralisation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of pH and fluoride concentration of dentifrices on fluoride levels in saliva, biofilm, and biofilm fluid in vivo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of irrigation and intracanal dressing on the healing process of dogs' teeth with apical periodontitis.

Dogs' teeth with apical periodontitis were treated endodontically, Dakin's solution being used in an experimental group as the irrigation solution, and camphorated paramonochlorophenol as an intracanal dressing. For a second group of teeth, the irrigation solution used was physiologic saline, dry cotton only being placed into the pulpal chamber to take the place of an intracanal dressing. In a second visit, overinstrumentation and a new application of the same kind of dressing were performed, the root canals being then filled with gutta-percha cones and zinc oxide-eugenol cement. Other specimens were treated, in one visit, where physiologic saline or Dakin's solution were the irrigation solutions. The animals were sacrificed 6 months after the obturation of the root canals. Histologic exams showed better results for the experimental group where Dakin's solution and camphorated paramonochlorophenol had been used, with signs of repair characterized by newly formed cementum and bone tissue, as well as a marked reduction in size of the periapical lesions. No differences were seen in the results with physiologic saline or Dakin's solution as irrigants.

A dental caries preventive program applied to children aged 5 to 8 years attending since the first year of age at the Baby Clinic of the Araçatuba Dental School, Brazil

Objective: Tooth decay is one of the more common diseases of childhood. Several studies recommend that early preventive measures must be implemented since the first years of life and continue throughout childhood and adolescence. The aim of the this study was to present results of a preventive dental program considering oral health maintenance, dental caries experience and the prevalence of dental caries relation with follow-up compliance visits. Material end method: Intraoral and interproximal radiographic exams were performed on 171 patients participants of a preventive dental program. Data regarding age, gender, previous caries experience and the frequency at which the patients attended return visits were obtained from the records. The data were analyzed statistically by the McNemar test, with the level of significance set at 1%. Result: Clinical and radiographic examination revealed that most children participating in the program had sound teeth (77.2 and 84.8%, respectively). The past dental history of the dental caries from patients included in this study showed statistical relevance when associated with the present dental caries experience and a statistical relationship was found from the absence of compliance to clinical visits and the dental caries presence. Conclusion: The preventive strategy had a positive influence on oral health maintenance in the children examined. Previous caries experience and the lack of compliance with return visits influenced the clinical oral condition of the children during participation in the preventive program.

A comparative analysis of caries and fluorosis among cities with and without public water supply fluoridation in São Paulo State, Brazil

Purpose: This population-based, cross-sectional study aimed to record the DMFT index for 12 year-old children with dental caries and fluorosis levels in cities with and without public water supply fluoridation. Methods: From the 101 municipalities belonging to the Health Regional Department XV (DRSXV-SJRP) of the São Paulo state in the Southeast region of Brazil, 85 cities were selected after exclusion of those with incomplete data and less than ten years of fluoridation treatment in 2004. The criteria adopted for the assessment of dental caries and fluorosis levels were based on the guidelines published in the WHO Manual 4th edition. The data were analyzed using Fisher’s exact tests at a significance level of 5%. Results: The prevalence of caries in 12 year-old children had no significant association with fluoridated water, and was considered “moderate” and “high” in cities without fluoridation and “low” and “moderate” in cities with fluoridation. A significant association was found between water fluoridation and fluorosis (P=0.001), but not between water fluoridation and the DMFT index (P=0.119). Conclusion: The prevalence of fluorosis was related to water fluoridation in this study. However, fluorosis was also observed in non-fluoridated cities, which may result from fluoride intake through other sources.

Protective efficacy of psidium cattleianum (Sabine) and myracrodruon urundeuva (Allemao) leaf extracts against caries development in rats

This study evaluated the influence of Psidium cattleianum Sabine (Myrtaceae) and Myracrodruon urundeuva Allemão (Anacardiaceae) aqueous extracts on S. mutans counts and dental enamel micro-hardness of rats submitted to a cariogenic challenge. Sixty Wistar rats were distributed in three groups and received water (control) or aqueous extracts of Psidium cattleianum or Myracrodruon urundeuva as hydration solution. Initially the animals had their sublingual and submandibular salivary glands surgically removed and the parotid ducts ligated. Then the rats were inoculated with 106 CFU of Streptococcus mutans ATCC 35668 and were fed with a cariogenic diet. To detect and quantify the presence of S. mutans, oral biofilms were sampled and microbial DNA was extracted and submitted to amplification by means of real-time PCR (Polymerase Chain Reaction). After seven weeks the animals were sacrificed and enamel demineralization was analyzed by cross-sectional micro-hardness. Both extracts produced a significant reduction on S. mutans counts and decreased the enamel demineralization. It can be concluded that the extracts tested had a significant effect on S. mutans in oral biofilm of the rats, decreasing S. mutans accumulation and enamel demineralization.

Clinical evaluation of a composite resin and a resin-modified glass-ionomer cement in non -carious cervical lesions: one year result

Objectives: The objective of this study was to evaluate the clinical performance of 124 non-carious cervical lesion restorations at 12 months. Materials And Methods: Three study groups were formed according to the material and technique used. All teeth received 37% phosphoric acid etching in enamel and dentin. The teeth of Group I received the conventional adhesive system Scotch Bond Multi Purpose, followed by resin composite Filtek Z350; teeth of Group II were restored with resin-modified glass-ionomer cement Fuji II LC; teeth of Group III were restored with the same resin-modified glass-ionomer cement however, before it was inserted, 2 coats of primer of the Scotch Bond Multi Purpose adhesive system were applied to dentinal tissue. The teeth were evaluated by 2 examiners with regard to the factors of retention, marginal adaptation, marginal discoloration, color alteration, presence of marginal caries lesion, anatomic shape, and sensitivity. Results: Application of the Kruskal-Wallis test showed no statistically significant difference for anatomic shape, marginal discoloration, color alteration, caries lesion, marginal adaptation, and sensitivity among the three study groups, but the variable retention presented statistically significant difference at 12 months, with Group III presenting a behavior superior to that of Group II but similar to that of Group I. Conclusion: The analyzed restorations of non-carious cervical lesions presented a good clinical performance at 12 months.