Effect of sodium hypochlorite on primary dentin--a scanning electron microscopy (SEM) evaluation

OBJECTIVE: The aim of this study was to evaluate the alterations of etched deciduous dentin when submitted to different time and concentrations of sodium hypochlorite (NaOCl), using scanning electron microscopy (SEM). MATERIAL AND METHODS: Forty deciduous anterior teeth were selected, cleaned and ground until expose a flat dentin area on the buccal surface. The specimens were randomly distributed into eight groups (n=5), according to dentin surface treatment (35% phosphoric acid etching for 7s--AE and/or NaOCl application), NaOCl solution concentration (5% or 10%), and time of application (0, 30, 60, and 120 s), as follows: G1: control (without AE and NaOCl); G2: only AE; G3, G4, and G5: AE+5% NaOCl for 30, 60, and 120 s, respectively; G6, G7, and G8: AE+10% NaOCl for 30, 60, and 120 s, respectively. All specimens were prepared for SEM analysis and the photomicrographs (three for each specimen) were classified according to a score as follow: 0: presence of smear layer (SL); 1: absence of SL+non-altered collagen fibrils; 2: absence of SL+collagen fibrils slightly altered; 3: absence of SL+collagen fibrils severely altered; and 4: absence of SL and absence of collagen fibrils. Data were submitted to Kruskal-Wallis and Mann-Whitney tests (p<0.05). RESULTS: All groups treated with NaOCl solution were significant different from G1 and G2, and showed alterations on the collagen fibrils network. Collagen complete removal was only observed when a 5% NaOCl solution was applied for 120 s and 10% NaOCl solution for 30, 60, and 120 s. CONCLUSIONS: The NaOCl action produced significant changes in the etched deciduous dentin. The higher NaOCl concentration, the lower the time required to completely removing the collagen fibrils network in deciduous dentin.     

AIRPOLISHING EFFECT ON BOVINE ENAMEL AND THE POSTERIOR REMINERALIZING EFFECT OF SALIVA. AN IN VITRO STUDY

Purpose:

The aim of the present study was to evaluate the alterations of surface microhardness and wear caused by the sodium bicarbonate jet on bovine enamel and the further remineralizing effect of artificial saliva.

Methods:

Fifteen enamel samples (4,0mm × 4,0mm) were used, which constituted the groups: no treatment (MI); treatment with sodium bicarbonate jet (MII and DI); treatment with sodium bicarbonate jet and immersion in saliva for one hour (MIII and DII), 24 hours (MIV and DIII) and 7 days (MV and DIV). Microhardness tests were carried out using a microdurometer in groups M and wear tests by a rugosimeter in groups D. The data were assessed by the one criterion variance analysis and Tukey test.

Results:

The mean value of microhardness, in KHN, in groups MI, MII, MIII, MIV and MV were 359,80; 335,46; 369,20; 377,73 and 341,86, respectively, whereas the mean values in μm, of wear for group DI, DII, DIII and DIV were 0,564; 0,519; 0,441 and 0,428, respectively.

Conclusions:

The sodium bicarbonate jet caused a wear and a reduction in microhardness on the enamel surface; saliva promoted the recovery of initial condition surface microhardness and reduced the wear; the repairing effect of saliva on the surface microhardness alterations occurred within one hour of treatment, having no significant statistical difference from the effect obtained in 24 hours; the best saliva repairing effect on the wear occurred with treatment of 24 hours.     

Horizontal root fracture with displacement in the primary dentition

Root fractures in the primary dentition are uncommon and little information is available concerning adequate treatment and prognosis. The most recently published guidelines recommend more invasive approaches but also discuss the need for further studies. This article examines how a horizontal root fracture in the primary dentition of a 3-year-old girl was treated by reducing the coronal fragment, followed by semi-rigid containment for 21 days. Radiographs taken one year after the initial trauma confirmed the success of this alternative approach.     

How may stressful experiences contribute to the development of temporomandibular disorders?

Temporomandibular disorders (TMD) comprise the most common cause of chronic facial pain conditions, and they are often associated with somatic and psychological complaints including fatigue, sleep disturbances, anxiety, and depression. For many health professionals, the subjectivity of pain experience is frequently neglected even when the clinic does not find any plausible biologic explanation for the pain. This strictly biomedical vision of pain cannot be justified scientifically. The purpose of this study is to demonstrate, by original articles from the literature and recent studies conducted in our own laboratory, the biological processes by which psychological stress can be translated into the sensation of pain and contribute to the development of TMD. The role of the hypothalamic–pituitary–adrenal axis, the serotoninergic and opioid systems in the pathogenesis of facial pain is exposed, including possible future therapeutic approaches. It is hoped that knowledge from apparently disparate fields of dentistry, integrated into a multidisciplinary clinical approach to TMD, will improve diagnosis and treatment for this condition through a clinical practice supported by scientific knowledge.     

Contact stomatitis due to palladium in dental alloys: a clinical report

A patient was treated with a maxillary gold-palladium alloy fixed partial denture (FPD). Shortly after placement, the patient contracted severe contact mucositis. Patch-testing revealed a positive reaction to palladium chloride (PdCl 2 , 1% petrolatum) but not to any other component of the prosthesis. After removal of the FPD and placement of a provisional acrylic resin restoration, all signs and symptoms disappeared. A definitive metal-ceramic (titanium-porcelain) prosthesis was placed, and no signs of lesions appeared. This clinical report demonstrates that titanium may be a satisfactory alternative for patients who require prostheses and are sensitive to other metals.     

Intracanal reinforcement fiber in pediatric dentistry: a case report.

A technique for the restoration of carious primary maxillary incisors using indirect resin composite crowns and intracanal reinforcement fiber is described. Endodontic treatment was previously performed on each tooth. The advantages of using an intracanal reinforcement fiber include resin composite crown reinforcement, translucency, and relative manipulation facility. In addition, the use of indirect resin composite crowns provides good shape and esthetics, as well as reduced chair time for the child. The technique is illustrated in a case report in which indirect resin composite crowns and an intracanal reinforcement fiber are placed in a 3-year-old girl.     

Federal University of Santa Catarina follow-up management routine for traumatized primary teeth – part 1

Abstract –  The objective of this study was to verify if the follow-up management routine of traumatized primary teeth set up by Federal University of Santa Catarina, which performs clinical and radiographic assessments (15 and 45 days; 4, 8 and 12 months) after the oral trauma, enabled an early diagnosis of sequelae which would indicate the need for endodontic intervention, as well as the influence a type of trauma and the child's age could have in the severity of the sequelae. In this study 52 sets of records were used of patients being seen in the last 6 months, with a total of 70 teeth that were receiving follow-up treatment. Patients returned for regular visits set up by the management routine, where clinical and radiographic examinations were performed to check for sequelae, which justified endodontic intervention. Mobility (51.2%) and crown discoloration (25.6%) were the most common sequelae found in the patient's first appointment. In the follow-up visits, replacement root resorption (22.5%) was the second most common sequela found, suggesting endodontic intervention. No significant association was found between severe sequelae, types of trauma and a child's age ( χ ² = 0.3, P  = 0,8613). During the intervals of the follow-up visits, it was noticed that between 46 days and 8 months a higher number of sequelae were diagnosed ( P  < 0.05). The diagnosis of sequelae such inflammatory and replacement root resorption, which can lead to an early loss of a primary tooth, are frequent and that the interval between the follow-up visits has to be changed, suggesting the setting up of management routine 2. The study also concluded that the type of trauma and the child's age are not fundamental factors in the diagnosis of severe sequelae.     

Factors influencing fluoride ingestion from dentifrice by children

Kobayashi CAN, Belini MR, Italiani FM, Pauleto ARC, Julianelli de Araújo J, Tessarolli V, Grizzo LT, Pessan JP, Machado MAAM, Buzalaf MAR. Factors influencing fluoride ingestion from dentifrice by children. Community Dent Oral Epidemiol 2011; 39: 426–432. © 2011 John Wiley & Sons A/S Abstract – Objective: This study assessed the percentage of the amount of dentifrice loaded onto the toothbrush that is ingested by children, taking into account age, the amount of dentifrice used during toothbrushing, and the dentifrice flavor. Methods: The sample consisted of 155 children of both genders attending public kindergartens and schools in Bauru, Brazil, divided into 5 groups (n = 30–32) of children aged 2, 3, 4, 5 and 6 years old. The dentifrices used were Sorriso? (1219 ppm F, peppermint‐flavored) and Tandy? (959 ppm F, tutti‐frutti‐flavored). The assessment of fluoride intake from dentifrices was carried out six times for each child, using 0.3, 0.6, and 1.2 g of each dentifrice, following a random, crossover distribution. Brushing was performed by the children or their parents/caregivers according to the home habits and under the observation of the examiner. Fluoride present in the expectorant and on toothbrush was analyzed with an ion‐specific electrode after HMDS‐facilitated diffusion. Fluoride ingestion was indirectly derived. Results were analyzed by 3‐way repeated‐measures anova and Tukey’s tests (P < 0.05) using the percent dentifrice ingested as response variable. Results: Age and percent dentifrice ingested for both dentifrices, and the three amounts used were inversely related (P < 0.0001). Percent dentifrice ingested was significantly higher after the use of Tandy? under all conditions of the study when compared with Sorriso? (P < 0.0001). Significant differences were observed when brushing with 0.3 g when compared with 1.2 g, for both dentifrices tested (P < 0.05). Conclusions: The results indicate that all variables tested must be considered in preventive measures aiming to reduce the amount of fluoride ingested by young children.     

Effects of phosphoric acid on bovine enamel bleached with carbamide peroxide

The aim of this study was to measure the demineralization capacity of 37% phosphoric acid on bovine enamel at different time-points after bleaching with 30% carbamide peroxide. Five, 4 × 4-mm sections were obtained from the enamel of 10 bovine incisors. After applying 30% carbamide peroxide (Vivastyle) for 90 min, specimens were stored in artificial saliva for 0, 24, 72 h, or 7 d and then immersed in 37% phosphoric solution. At 15, 30, 60, 90, and 120 s, 5-ml aliquots were extracted. A control group of specimens was not bleached. Ca²⁺ concentrations were measured by atomic absorption spectrophotometry. A larger amount of Ca²⁺ was extracted from enamel by phosphoric acid after the application of 30% carbamide peroxide. Twenty-four hours after bleaching, significantly more Ca²⁺ was extracted from bleached than from control specimens at all time-points, and this greater susceptibility to the action of the acid persisted for at least 1 wk after bleaching.     

The inhibitory effect of MI paste, fluoride and a combination of both on the progression of artificial caries-like lesions in enamel

This in-vitro study evaluated the inhibition of demineralization in enamel sections produced by MI paste, fluoride and a combination of both, compared to artificial saliva and NaF 5000 ppm in a caries progression pH-cycling model. Twenty-one teeth were demineralized to create subsurface enamel lesions (approximately 200 microns in depth). The teeth were sectioned and characterized using polarized-light-microscopy (PLM). A single section from each lesion was assigned to a treatment group: Artificial saliva, NaF 5000 ppm (Prevident, Colgate), MI paste (Recaldent, GC America Inc), NaF 1100 ppm (Crest, Procter & Gamble) and NaF 1100 ppm plus MI paste. The sections were covered with varnish except for an exposed window on the external surface of the lesion and placed in a six-day pH-cycling model with two daily treatment applications of two minutes each. The sections were characterized by PLM, and the lesion areas were measured using a digital image analysis system. Based on a paired-sample t-test, significant differences (p < .05) in percentage of change in lesion size were found between the high fluoride group and all the other groups. No significant difference was found between the artificial saliva and MI paste group, neither was there any significant difference between the NaF 1100 ppm, the combined application group or the MI paste group alone. In conclusion, the higher concentration of NaF (5000 ppm) reduced lesion progression to the greatest extent. The MI paste group did not show any effect on the inhibition of lesion progression. Further studies on the preventive effect and longer treatment applications are recommended.