Optical clearing agents based on metallic and dielectric nanoparticles for caries diagnostic by optical coherence tomography.

OBJECTIVE: This study aimed to assess the effect of titanium dioxide (TiO2) and silver (Ag) nanoparticles dispersed in glycerol or water, serving as optical clearing agents nanocolloids (OCAs-NC), for improving optical coherence tomography (OCT) images and highlighting incipient lesions in ex vivo human teeth. MATERIALS AND METHODS: Twelve human teeth with incipient lesions were divided into seven groups according to the OCA-NC; they were subjected to G1 (air), G2 (glycerol), G3 (TiO2 0.1%), G4 (TiO2 0.01%), G5 (TiO2 0.001%), G6 (AgNO3 10%), and G7 (AgNO3 100%). The OCA-NC was applied to the occlusal surface, and two-dimensional images of the specimens were analyzed using OCT (930 nm central wavelength; 100 nm bandwidth; 5 mW output power; axial resolution of 7/5.3 µm in water and air, respectively; lateral resolution of 8 µm; and light penetration depth of 1.6 mm inside the sample). RESULTS: The findings demonstrated that the utilization of OCAs-NC containing metallic or dielectric nanoparticles (AgNO3 and TiO2) led to improved differentiation between sound and demineralized enamel on occlusal surfaces. Additionally, it enhanced the depth of image penetration when analyzing this hard tissue with OCT. CLINICAL RELEVANCE: In the current context of minimally invasive dentistry, the use of OCAs-NC in conjunction with OCT can provide clinicians with early diagnosis, allowing for the determination of less/more invasive therapies and consequently halting the disease before cavitation of dental tissues occurs.

Evaluation of the Antimicrobial Effect of Photodynamic Therapy and Er:YAG Laser Irradiation on Root Canals Infected with Enterococcus faecalis.

Objective: To carry out a histological and morphometric analysis of the antimicrobial effect of Er:YAG laser irradiation combined with photodynamic therapy (PDT) on root canals infected with Enterococcus faecalis. Background: PDT and Er:YAG laser irradiation may be alternatives for effective endodontic disinfection but there are no data on the combination of these therapies. Materials and methods: Forty single-rooted bovine teeth had their roots contaminated with E. faecalis for 72 h. The teeth were randomly divided into four groups (n = 10): group 1, irrigation with 2.5% sodium hypochlorite (NaOCl); group 2, Er:YAG laser (λ2940 nm, 15 Hz, 100 mJ); group 3, PDT with 0.07% methylene blue as photosensitizer and laser irradiation (λ660 nm, power 40 mW, 5 min); and group 4, Er:YAG laser + PDT. After treatment, the teeth were examined by confocal laser scanning microscopy to verify bacterial viability, and morphometric analysis of the images was performed. Results: The PDT and Er:YAG + PDT treatments promoted the greatest reduction in bacteria among the proposed therapies, whereas 2.5% NaOCl was the least effective in bacterial elimination. A statistically significant difference (p < 0.05) was observed among the groups studied, except between the group combining Er:YAG and PDT and the group treated with PDT alone. Conclusions: PDT combined or not with Er:YAG laser was found to be more effective in root canal disinfection when compared with the other groups.

The use of photobiomodulation therapy or LED and mineral trioxide aggregate improves the repair of complete tibial fractures treated with wire osteosynthesis in rodents.

The repair of large bone defects is lengthy and complex. Both biomaterials and phototherapy have been used to improve bone repair. We aimed to describe histologically the repair of tibial fractures treated by wiring (W), irradiated or not, with laser (λ780 nm, 70 mW, CW, spot area of 0.5 cm2, 20.4 J/cm2 (4 × 5.1 J/cm2, Twin Flex Evolution®, MM Optics, Sao Carlos, SP, Brazil) per session, 300 s, 142.8 J/cm2 per treatment) or LED (λ850 ± 10 nm, 150 mW, spot area of 0.5 cm2, 20.4 J/cm2 per session, 64 s, 142.8 J/cm2 per treatment, Fisioled®, MM Optics, Sao Carlos, Sao Paulo, Brazil) and associated or not to the use of mineral trioxide aggregate (MTA, Angelus®, Londrina, PR, Brazil). Inflammation was discrete on groups W and W + LEDPT and absent on the others. Phototherapy protocols started immediately before suturing and repeated at every other day for 15 days. Collagen deposition intense on groups W + LEDPT, W + BIO-MTA + LaserPT and W + BIO-MTA + LEDPT and discrete or moderate on the other groups. Reabsorption was discrete on groups W and W + LEDPT and absent on the other groups. Neoformation varied greatly between groups. Most groups were partial and moderately filed with new-formed bone (W, W + LaserPT, W + LEDPT, W + BIO-MTA + LEDPT). On groups W + BIO-MTA and W + BIO-MTA + LaserPT bone, neoformation was intense and complete. Our results are indicative that the association of MTA and PBMT (λ = 780 nm) improves the repair of complete tibial fracture treated with wire osteosynthesis in a rodent model more efficiently than LED (λ = 850 ± 10 nm).

Photobiomodulation Therapy in the Proliferation and Differentiation of Human Umbilical Cord Mesenchymal Stem Cells: An In Vitro Study.

Introduction: Since photobiomodulation therapy (PBMT) favors in vitro mesenchymal stem cell (MSC) preconditioning before MSC transplantation, increasing the proliferation of these cells without molecular injuries by conserving their characteristics, in the present in vitro study we analyzed the effect of PBMT on the proliferation and osteogenic differentiation of human umbilical cord mesenchymal stem cells (hUCMSCs). Methods: Irradiation with an InGaAIP Laser (660 nm, 10 mW, 2.5 J/cm2 , 0.08 cm2 spot size, and 10 s) was carried out. The cells were divided into four groups: CONTROL [cells grown in Dulbecco's Modified Eagle Medium (DMEM)], OSTEO (cells grown in an osteogenic medium); PBMT (cells grown in DMEM+PBMT), and OSTEO+PBMT (cells grown in an osteogenic medium plus PBMT). The cell proliferation curve was obtained over periods of 24, 48 and 72 hours using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Osteogenic differentiation was analyzed by the formation of calcium nodules over periods of 7, 14 and 21 days. Morphometric analysis was performed to quantify the total area of nodular calcification. Results: The highest cell proliferation and cell differentiation occurred in the OSTEO+PBMT group, followed by the PBMT, OSTEO and CONTROL groups respectively, at the observed times (P <0.05). Conclusion: PBMT enhanced the osteogenic proliferation and the differentiation of hUCMSCs during the periods tested, without causing damage to the cells and preserving their specific characteristics, a fact that may represent an innovative pretreatment in the application of stem cells.

Influence of the Restorative Strategy on Push-out Bond Strength of the Self-adhesive Composite.

AIM: This study evaluated the influence of the resin composite and bonding strategy on the push-out bond strength of the self-adhesive, Fusio liquid dentin (FUS) (Pentron Clinical), and of two conventional resin composites of different viscosities, Filtek Z250 (3M ESPE) and tetric flow (Ivoclar Vivadent). MATERIALS AND METHODS: Thirty-two bovine incisors were used after disinfection. The roots were sectioned and the buccal and lingual surfaces were polished until a 2-mm slab was achieved, maintaining enamel at the buccal surface and dentin at the lingual surface. Standardized cavities were then prepared (2.0 × 1.5 mm) and restored according to the following bonding strategies: Fusio liquid dentin with selective etching (FUSSE) in enamel, FUS, Filtek Z250, and tetric flow-total etching (TET). All groups were restored in bulk. After 24 hours of storage in distilled water, finishing and polishing were performed. The push-out test was conducted on a universal testing machine (0.05 mm/minute). Data were analyzed through Kruskal-Wallis and Mann-Whitney tests (p = 0.05). The extruded restorations were evaluated under a stereomicroscope (10×) for failure-mode evaluation. RESULTS: There were no statistically significant differences between the groups TET, Z250, and FUS, with 145.59, 108.91, and 104.12 MPa means, respectively. The FUSSE group (40.92 MPa) showed a statistically significant lower bond strength. The predominant failure mode was a mixed failure for all groups. CONCLUSION: The self-adhesive resin composite achieved a satisfactory result on bond strength when compared to conventional composites with regular and low viscosities, except when selective enamel etching was done. CLINICAL SIGNIFICANCE: This study shows that the clinicians must be aware of the viscosity of the phosphoric acid to avoid dentin contamination whenever performing selective enamel etching. And the self-adhesive resin composite studied presented as another restorative alternative.

Photobiomodulation Therapy in Bone Repair Associated with Bone Morphogenetic Proteins and Guided Bone Regeneration: A Histomorphometric Study.

OBJECTIVE: To evaluate the efficacy of photobiomodulation for bone repair of critical surgical wounds with implants of bone morphogenetic proteins (BMPs) and bovine biological membranes, using histological and histomorphometric analysis. BACKGROUND: Tissue engineering has been developing rapidly through the use of various biomaterials for the treatment of bone defects, such as mechanical barriers consisting of biological membranes and implants of biomaterials for bone supply. MATERIALS AND METHODS: Thirty-two male rats were divided into four groups (n = 8): group I-C: control; group II-PT: photobiomodulation therapy; group III-PM: Gen-Pro® BMPs+Gen-Derm® membrane; and group IV-PMPT: Gen-Pro® BMPs+Gen-Derm® membrane+photobiomodulation therapy. A 3 mm bone cavity was performed in the upper third of the lateral surface of the right rat femur to obtain a bone defect considered to be critical. The irradiated groups received seven applications of AlGaAs diode laser 830 nm, P = 40 mW, continuous wave (CW) emission mode, f ∼ 0.6 mm, 4 J/cm2 per point (north, south, east, and west) at 48 h intervals, for a total of 16 J/cm2 per session (final dose: 112 J/cm2). Bone repair was evaluated at sacrifice 15 and 30 days after the procedure. The specimens were embedded in paraffin and stained with hematoxylin and eosin and Picrosirius for analysis by light microscopy and by the Leica interactive measurement module software. Statistical analysis was performed (p < 0.05%). RESULTS: Histological analysis confirmed the histomorphometric results, with the experimental groups showing bone neoformation of significantly higher quality and quantity at the end of 30 days compared with the control group. CONCLUSIONS: Photobiomodulation therapy was effective for bone repair mainly when associated with BMPs and a biological membrane. The results of this study are promising and stimulate further scientific and clinical research.

Dental Implant in the Canalis Sinuosus: A Case Report and Review of the Literature.

The canalis sinuosus is a neurovascular canal, a branch of nerve of infraorbital canal, through which the anterior superior alveolar nerve passes and then leans medially in course between the nasal cavity and the maxillary sinus, reaching the premaxilla in the canine and incisor region. The purpose of this article is to report a case with the presence of canalis sinuosus, in order to alert and guide professionals and discuss the morphology of this anatomical variation avoiding trans- and postsurgical disorders in dental implants. A 51-year-old female was attended to in a radiology clinic, reporting paresthesia in the right upper lip region and painful symptomatology after the installation of an implant in the corresponding region. The case revealed the presence of canalis sinuosus in imaging exams. The knowledge of this anatomical variation is essential for professionals, because attention to this region prevents irreversible damage. Therefore, the use of imaging examinations is recommended during the planning stages and treatment and after surgery in patients undergoing surgery in this area.

Fs-laser ablation of teeth is temperature limited and provides information about the ablated components.

The goal of this work is to investigate the thermal effects of femtosecond laser (fs-laser) ablation for the removal of carious dental tissue. Additional studies identify different tooth tissues through femtosecond laser induced breakdown spectroscopy (fsLIBS) for the development of a feedback loop that could be utilized during ablation in a clinical setting. Scanning Election Microscope (SEM) images reveal that minimal morphological damages are incurred at repetition rates below the carbonization threshold of each tooth tissue. Thermal studies measure the temperature distribution and temperature decay during laser ablation and after laser cessation, and demonstrate that repetition rates at or below 10kHz with a laser fluence of 40 J/cm2 would inflict minimal thermal damage on the surrounding nerve tissues and provide acceptable clinical removal rates. Spectral analysis of the different tooth tissues is also conducted and differences between the visible wavelength fsLIBS spectra are evident, though more robust classification studies are needed for clinical translation. These results have initiated a set of precautionary recommendations that would enable the clinician to utilize femtosecond laser ablation for the removal of carious lesions while ensuring that the solidity and utility of the tooth remain intact.

Photodynamic Inactivation of Cariogenic Pathogens Using Curcumin as Photosensitizer.

OBJECTIVE: This investigation assessed the susceptibility of Streptococcus mutans and Lactobacillus acidophilus to Photodynamic Therapy (PDT) when grown simultaneously in dentine carious lesions. BACKGROUND DATA: PDT is a technique that utilizes light to activate photosensitizers in the presence of oxygen to produce reactive radicals. MATERIALS AND METHODS: A culture medium of 1% glucose, 2% sucrose, 1% young primary culture of L. acidophilus 108 CFU/mL, and S. mutans 108 CFU/mL was utilized to inoculate the bacterial induced caries on human dentine slabs. Different concentrations of the photosensitizer (0.75, 1.5, 3.0, 4.0, and 5.0 g/L) were activated through exposure to the light-emitting diode source with a central wavelength of 450 nm and a fluency of 5.7 J/cm2. Two light intensities (19 and 47.5 mW/cm2) were tested. Four different groups were analyzed: L-D- (control group), L-D+ (drug group), L+D+1 (PDT group 1, light intensity of 19 mW/cm2), and L+D+2 (PDT group 2, light intensity of 47.5 mW/cm2). ANOVA/Tukey tests were utilized to compare groups (α = 5%). RESULTS: Both light intensities required 5.0 g/L of curcumin for significant bacterial reduction (p < 0.05). No significant effect was found for L-D+, thus proving the absence of a potential inherent toxicity. CONCLUSIONS: Curcumin has a toxic effect on microorganisms at appreciable concentrations upon photoactivation. However, it was required to use the maximum concentration of the drug for a successful procedure.

The Promising Applications of Stem Cells in the Oral Region: Literature Review.

INTRODUCTION: For a long time researchers have tried to find out a way to grow tissues back to the human body in order to solve transplantation problems by offering the unique opportunity to have their organs back, working properly, in search of life dignity. LITERATURE REVIEW: Stem cells seem to be present in many other tissues than researchers had once thought; and in some specific sites they can be easily collected, without the need of expensive interventions. The oral cavity is one of these regions where their collection can be accomplished, with plenty of accessible sites enriched with these precious cells. AIM: The aim of this literature review is to research where in the mouth can scientists find stem cells to be used in the near future. KEY-MESSAGE: The aim of this literature review is to research where stem cells can be found and collected in the oral cavity.

Detection of vertical root fractures in endodontically treated teeth in the absence and in the presence of metal post by cone-beam computed tomography.

BACKGROUND: Aim of this study was to investigate the influence of gutta-percha and metallic posts on the efficiency of Cone Beam Computed Tomography (CBCT) in diagnosing Vertical Root Fracture (VRF). METHODS: Forty-eight teeth were divided into 3 experimental and 3 control groups. The teeth of the first experimental group and the first control group received neither gutta-percha nor metal posts. The teeth of the second experimental group and the second control group were filled with gutta-percha, and the teeth of the third experimental group and the third control group were filled with the metal posts. The teeth of the experimental groups were artificially fractured. The teeth were evaluated through images taken by a Prexion scanner with a 0.1 mm resolution. Fisher's exact test was used to measure the following values: sensitivity, false negative, specificity, false positive and accuracy for the VRF detection through the scanner. Three observers calibrated and blinded to the protocol evaluated the images. RESULTS: The inter-observer Kappa coefficient was 0.83. The presence of posts and gutta-percha reduced the sensitivity and the accuracy in detecting the VRF. Regarding to the sensitivity (p = 0.837, p = 0.304, p = 0.837 for evaluator 1, 2 and 3, respectively) and specificity (p = 0.162, p = 0.056, p = 0.062 for evaluator 1, 2 and 3, respectively), Fisher's exact test showed no statistically significant difference among the evaluated groups. However, a significant difference was observed in relation to the accuracy in the results of evaluator 2 (p = 0.03), which showed a much lower accuracy for the post group (50 %) than for the Nonfilled group (93.8 %). CONCLUSIONS: The Prexion tomograph was precise in detecting vertical root fractures and the CBCT diagnostic ability was not influenced by the presence of posts or gutta-percha.

Analysis of Dental Enamel Surface Submitted to Fruit Juice Plus Soymilk by Micro X-Ray Fluorescence: In Vitro Study.

OBJECTIVE: This paper aimed to analyze the in vitro industrialized fruit juices effect plus soy to establish the erosive potential of these solutions. MATERIALS AND METHODS: Seventy bovine incisors were selected after being evaluated under stereomicroscope. Their crowns were prepared and randomly divided into 7 groups, using microhardness with allocation criteria. The crowns were submitted to the fruit juice plus soy during 15 days, twice a day. The pH values, acid titration, and Knoop microhardness were recorded and the specimens were evaluated using X-ray microfluorescence (µXRF). RESULTS: The pH average for all juices and after 3 days was significantly below the critical value for dental erosion. In average, the pH value decreases 14% comparing initial time and pH after 3 days. Comparing before and after, there was a 49% microhardness decrease measured in groups (p < 0.05). Groups G1, G2, G5, and G6 are above this average. The analysis by µXRF showed a decrease of approximately 7% Ca and 4% P on bovine crowns surface. Florida (FL) statistical analysis showed a statistically significant 1 difference between groups. Thus, a tooth chance to suffer demineralization due to industrialized fruit juices plus soy is real.

Apical Extrusion of Debris Produced during Continuous Rotating and Reciprocating Motion.

This study aimed to analyse and compare apical extrusion of debris in canals instrumented with systems used in reciprocating and continuous motion. Sixty mandibular premolars were randomly divided into 3 groups (n = 20): the Reciproc (REC), WaveOne (WO), and HyFlex CM (HYF) groups. One Eppendorf tube per tooth was weighed in advance on an analytical balance. The root canals were instrumented according to the manufacturer's instructions, and standardised irrigation with 2.5% sodium hypochlorite was performed to a total volume of 9 mL. After instrumentation, the teeth were removed from the Eppendorf tubes and incubated at 37°C for 15 days to evaporate the liquid. The tubes were weighed again, and the difference between the initial and final weight was calculated to determine the weight of the debris. The data were statistically analysed using the Shapiro-Wilk, Wilcoxon, and Mann-Whitney tests (α = 5%). All systems resulted in the apical extrusion of debris. Reciproc produced significantly more debris than WaveOne (p < 0.05), and both systems produced a greater apical extrusion of debris than HyFlex CM (p < 0.001). Cross section and motion influenced the results, despite tip standardization.

Clinical aspects in the treatment planning for rehabilitation with overdenture and protocol-type prosthesis / Aspectos clínicos utilizados no planejamento de prótese overdenture e protocolo

Objective: The aim of this study was to criticaly review the published literature regarding the clinical aspects involved in the rehabilitation of edentulous patients using Branemark protocol and overdenture prostheses.Methods: An active search was conducted in the LILACS, MEDLINE, PubMed, and SciELO databases using the descriptors: "Coating for dentures" (Overlay Prosthesis and Overdenture) and "Implant-supported fixed dental prosthesis" (Protesis dental de suporte implantado, Dental prosthesis, and Implant Supported Prosthesis) in Portuguese, English, and Spanish between January 2000 and October 2014.Results: The following parameters should be considered when selecting between Branemark protocol and overdenture prostheses: bone support, lip support, lip-line, upper lip length, oral mucosa conditions and size, alveolar ridge contour, crown-bone ratio, interarch space, and speaking space. Overdenture rehabilitation can provide many benefits to patients, such as prosthetic retention, stability, comfort, and improved aesthetics.Conclusions: This study highlights the need for a thorough individualized treatment planning to ensure that fixed prostheses and overdentures have an excellent prognosis when used appropriately in suitable patients at the appropriate time.

Objetivo: Verificar por meio de revisão crítica da literatura os aspectos clínicos durante o planejamento de pacientes edêntulos frente à utilização de próteses tipo protocolo de Branemark e overdenture.Métodos: Busca ativa nas bases de dados LILACS, MEDLINE, PubMed e SciELO por meio dos descritores: "Revestimento de dentadura" (Prótese de Recobrimento e Overdenture) e "Prótese dentária fixada por implante" (Protesis dental de suporte implantado e Dental prosthesis, implant supported) entre janeiro de 2000 até outubro de 2014 nas línguas Portuguesa, Inglesa e Espanhola.Resultados: Deve-se levar em consideração para indicar as próteses overdentures e protocolo o suporte ósseo, suporte labial, linha do sorriso, comprimento do lábio superior, qualidade e quantidade da mucosa, contorno do rebordo alveolar, relação coroa/osso, espaço interarcos e zona fonética. A reabilitação com overdenture pode trazer muitos benefícios ao paciente, tais como retenção, estabilidade, conforto, e a estética.Conclusões: Evidencia-se a necessidade de um planejamento individualizado, para que se chegue a um correto plano de tratamento, no qual as próteses fixas e overdentures possam ter um excelente prognóstico, desde que utilizadas no momento apropriado e no paciente indicado.

Prototipagem e cirurgia guiada em implantodontia: revisão de literatura / Prototyping and guided surgery in implantology: literature review

Objetivo: o objetivo deste estudo é fazer uma revisão de literatura descrevendo os benefícios, as vantagens e desvantagens de modelos de prototipagem para o planejamento e a redução do tempo em cirurgia. Revisão de literatura: a prototipagem rápida é uma tecnologia que permite a duplicação morfológica de estruturas anatômicas em escala real, obtidas por meio de exames de imagem, resultando nos chamados biomodelos, que permitem a visualização tridimensional das estruturas anatômicas complexas, facilitando o planejamento pré-operatório de implantes. Considerações finais: a prototipagem possui amplo uso em odontologia, mais especificamente no campo da implantodontia e cirurgia bucomaxilofacial. Consiste em uma técnica aplicável, pois permite a realização da cirurgia guiada. Bem como esses protótipos permitem a redução do tempo cirúrgico, do tempo necessário de anestesia e do risco de infecção. Em Implantodontia, a técnica da prototipagem facilita a obtenção dos guias cirúrgicos, tornando-se um diferencial para que se consiga um perfeito planejamento reverso, ou seja, uma boa dinâmica e estética agradáveis. A prototipagem e a cirurgia guiada representam um novo horizonte na implantodontia de forma que os procedimentos cirúrgicos se tornam mais simples, seguros e previsíveis. Com esse tipo de procedimento é possível otimizar o tempo da intervenção cirúrgica e ainda gerar um maior grau de confiança, devido às simulações e informações obtidas pelos biomodelos.

Oroantral fistulas closure using Bichat's fat pad / Fechamento de fístulas bucossinusais através do uso da bola de Bichat

The oroantral fistula is one of the complications most common after dental extractions in posterior maxillary, mainly in the region of second and third molar. The diagnosis is based on clinical signs and symptoms, which may be present in pain, fever, hyposmia and drainage of purulent discharge; additional examinations such as computed tomography and sinus nasal endoscopy improve diagnostic precision. It is therefore of paramount importance to correct early diagnosis and treatment avoiding in this way, the symptons of sinusitis, infections and dysphonia. Several surgical techniques have been proposed for the closure of the bucosinusal fistula; the use of Bichat´s fat pad has become a successful alternative among them. Many surgical treatments have been to propose for closure of bucosinusal fistula; Bichat fat pad has been a good alternative. The propose for this article is report two cases with closure of bucosinusal fistulas through Bichat's fat pad, as well as to discuss the surgical techniques, characteristics, indications and peculiarities.

A fístula bucosinusal ou oro-antral é uma das complicações mais comuns, após extrações dentárias na região posterior de maxila, principalmente em região de segundo e terceiro molares permanentes. O diagnóstico se baseia em sinais e sintomas clínicos, nos quais pode-se destacar: dor, febre, hiposmia e drenagem de secreção purulenta. Os exames complementares como a endoscopia sinonasal e a tomografia computadorizada melhoram a precisão diagnóstica. Assim, é de suma importância, o correto diagnóstico e tratamento precoce, evitando dessa maneira a instalação de sinusites, infecções e disfonia. Diversas técnicas cirúrgicas têm sido propostas na literatura, para o fechamento da fístula bucossinusal, dentre elas, a utilização do corpo adiposo de Bichat tem se tornado uma alternativa bem sucedida. O objetivo deste trabalho é relatar dois casos clínicos de fechamento de fístulas bucossinusais através do retalho da bola de Bichat, realizados pelo Departamento de Cirurgia e Traumatologia Bucomaxilofacial do Hospital da Face e Hospital da Restauração em Recife, Pernambuco. Ainda, descrever acerca de sua técnica cirúrgica, características, indicações e peculiaridades.

Effect of pH values of two bleaching gels on enamel microhardness.

This study evaluated the influence of bleaching gel pH and the effect of remineralizing gels after bleaching in different time intervals. Sixty bovine incisors were divided into 2 groups (n = 30). Group 1 was bleached with a 35% hydrogen peroxide (HP) acid gel and Group 2 was bleached with a 35% HP neutral gel. Each group was then divided into 3 subgroups (n = 10) according to the post-bleaching treatment used: storage in artificial saliva, application of a fluoride gel, or application of a gel consisting of fluoride, potassium nitrate, and nanostructured calcium phosphate. Specimens were stored in artificial saliva, and enamel microhardness was evaluated at 24 hours and 15 days postbleaching. Vickers microhardness data were analyzed by means of 2-way ANOVA, with repeated measurements and Bonferroni's post-hoc test. Twenty-four hours after bleaching, no significant differences were found between the bleaching gels. At 15 days postbleaching, Group 2 samples demonstrated a significant reduction in microhardness. No significant differences were found between the remineralizing gels, though all of the postbleaching treatments after the use of 35% neutral gel were able to re-establish baseline microhardness. It was concluded that neutral bleaching gel significantly reduced enamel microhardness 15 days after bleaching and that the use of remineralizing gels did not significantly enhance the microhardness of bleached enamel. However, in clinical situations, the acquired enamel pellicle protects tooth surfaces, and postbleaching, decalcified enamel would undergo recalcification. This study indicates that it is important to consider the bleaching agent's pH and composition when treating patients with reduced salivary secretion.

Effect of infrared laser in the prevention and treatment of paresthesia in orthognathic surgery.

Orthognathic surgery is the surgical procedure that makes correcting deformities of the bones in the region of the maxilla and mandible a reality in the Brazilian dentistry. However, this type of surgery usually involves paresthesia in the postoperative period, concerning the surgeons who perform them and generating discomfort to patients. This study aimed at evaluating the effect of infrared laser (830 nm) in the prevention and treatment of paresthesias after orthognathic surgery. Six patients underwent orthognathic surgery: the experimental group composed of 4 patients and the control group that did not receive laser therapy composed of 2 patients. The experimental group received laser applications during the transoperative and 12 postoperative sessions. Tests for mechanical (deep and shallow) and thermal (cold) sensitivity were performed in the preoperative and postoperative period (during 12 sessions) in the lip and chin areas by the same operator. The paresthesia was classified into 1, strong; 2, moderate; 3, mild; and 4, absent, through the patient's response to stimuli. The results showed that all patients had no disturbance of sensitivity in the preoperative period, but paresthesia was presented at various levels in the postoperative period. Both groups showed recovery of deep mechanical sensitivity within a shorter time interval compared with the superficial mechanical and thermal sensitivity. However, at the 12th assessment, patients who underwent the laser therapy showed better reduction in the level of paresthesia or even complete regression of this. The laser, therefore, brought benefits to the treatment of paresthesia, accelerating the return of neurosensorial sensitivity.

Evaluation of low-level laser therapy in patients with acute and chronic temporomandibular disorders.

The purpose of this study was to address the following question: among patients with acute or chronic temporomandibular disorders (TMD), does low-level laser therapy (LLLT) reduce pain intensity and improve maximal mouth opening? The sample comprised myogenic TMD patients (according Research Diagnostic Criteria for TMD). Inclusion criteria were: male/female, no age limit, orofacial pain, tender points, limited jaw movements and chewing difficulties. Patients with other TMD subtypes or associated musculoskeletal/rheumatologic disease, missing incisors teeth, LLLT contra-indication, and previous TMD treatment were excluded. According to disease duration, patients were allocated into two groups, acute (<6 months) and chronic TMD (≥ 6 months). For each patient, 12 LLLT sessions were performed (gallium-aluminum-arsenide; λ = 830 nm, P = 40 mW, CW, ED = 8 J/cm(2)). Pain intensity was recorded using a 10-cm visual analog scale and maximal mouth opening using a digital ruler (both recorded before/after LLLT). The investigators were previously calibrated and blinded to the groups (double-blind study) and level of significance was 5% (p < 0.05). Fifty-eight patients met all criteria, 32 (acute TMD), and 26 (chronic TMD). Both groups had a significant pain intensity reduction and maximal mouth opening improvement after LLLT (Wilcoxon test, p < 0.001). Between the groups, acute TMD patient had a more significant pain intensity reduction (Mann-Whitney test, p = 0.002) and a more significant maximal mouth opening improvement (Mann-Whitney test, p = 0.011). Low-level laser therapy can be considered as an alternative physical modality or supplementary approach for management of acute and chronic myogenic temporomandibular disorder; however, patients with acute disease are likely to have a better outcome.

Photodynamic effects of curcumin against cariogenic pathogens.

BACKGROUND DATA: The presence of Streptococcus mutans and Lactobacillus acidophilus in dental structure is an indicator of a cariogenic biofilm. Photodynamic therapy is a technique that involves the activation of photosensitizers by light in the presence of oxygen, resulting in the production of reactive radicals capable of inducing cell death. Reduction of bacteria levels can provide additional means of preventing dental caries. OBJECTIVE: The present study evaluated the susceptibility of planktonic cultures of S. mutans (ATCC 25175) and L. acidophilus (ATCC-IAL-523) from the Adolfo Lutz Institute (IAL) to photodynamic therapy after sensitization with curcumin and exposure to blue light at 450 nm. METHODS: Bacterial suspensions of S. mutans and L. acidophilus isolated (as single species) and combined (multspecies) were prepared and then evaluated. Four different groups were analyzed: L-D- (control group), L-D+ (drug group), L+D- (light group), and L+D+ (photodynamic therapy group). Two different concentrations of curcumin were tested (0.75 and 1.5 g/L) associated with a 5.7 J/cm(2) light emission diode. RESULTS: Significant decreases (p<0.05) in the viability of S. mutans were only observed when the bacterial suspensions were exposed to both curcumin and light. Then, reductions in viability of up to 99.99% were observed when using 1.5 g/L of the photosensitizer. The susceptibility of L. acidophilus was considerably lower (21% and 37.6%) for both curcumin concentrations. CONCLUSIONS: Photodynamic therapy was found to be effective in reducing S. mutans and L. acidophilus on planktonic cultures. No significant reduction was found for L-D+, proving the absence of dark toxicity of the drug.