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.

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.

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.

Diagnóstico de fraturas radiculares verticais em dentes tratados endodonticamente, com ou sem a presença de núcleos metálicos fundidos, empregando-se a tomografia computadorizada cone beam / Diagnosis of vertical root fractures in endodontically prepared teeth, with or without the presence of intracanals cast metallic posts using Cone Beam Computed Tomography

Objetivo: avaliar o diagnóstico de fraturas verticais em dentes tratados endodonticamente, com ou sem a presença de núcleos metálicos fundidos (NMF), por meio de tomografia computadorizada cone beam (TCCB), utilizando-se tomógrafo Prexion. Métodos: quarenta e oito pré-molares humanos extraídos, unirradiculares, constituíram a amostra, que foi dividida em três grupos: grupo 1, controle, 16 dentes sem a presença da guta-percha e do NMF, dos quais 8 foram artificialmente fraturados; grupo 2, 16 dentes com a presença da guta-percha, dos quais 8 foram artificialmente fraturados; grupo 3, 16 dentes com a presença do NMF, dos quais 8 foram artificialmente fraturados. Os dentes foram fraturados segundo método já consagrado na literatura. Um especialista em radiologia odontológica, com 10 anos de experiência em tomografia, avaliou as imagens. A sensibilidade, a especificidade e a acurácia foram calculados por meio de uma avaliação dicotômica (presença ou ausência de fratura). Resultados: por meio do teste exato de Fisher, não foi registrada diferença estatística entre os três grupos em relação à acurácia, à sensibilidade e à especificidade para o diagnóstico da fratura, porém ocorreu alto percentual de falso positivo para o grupo 3. Conclusão: a TCCB é um excelente recurso para o diagnóstico da fratura vertical; porém, a presença do NMF produz imagens com muitos artefatos, resultando em altos valores de falso positivos, sendo de suma importância unir os achados tomográficos aos sinais e sintomas clínicos para um diagnóstico o mais preciso possível da fratura

Influência da abertura coronária na localização dos canais radiculares em incisivos inferiores

Objetivo: avaliar a influência das formas de aberturas coronárias na localização dos canais radiculares em incisivos inferiores. Métodos: foram utilizados 32 dentes extraídos de humanos, sendo 16 com canal único e 16 com dois canais radiculares que receberam, inicialmente,aberturas coronárias ovais conservadoras, seguidas de montagem aleatória em manequim, para avaliação clínica do número de canais radiculares por dois especialistas.Após essa etapa, os acessos foram ampliados para forma triangular não conservadora, sendo submetidos a uma segunda avaliação clínica quanto ao número de canais radiculares. Resultados: nos exames das aberturas conservadoras, os examinadores 1 e 2 obtiveram,respectivamente, 15 (94%) e 14 (87%) acertos para os dentes com um canal, com nenhum (0%) e 5 acertos(31,2%) para os dentes com 2 canais. Após ampliar as aberturas, os examinadores 1 e 2 obtiveram, respectivamente,16 acertos (100%) nos casos com 1 canal, com 5 (31,2%) e 10 (62%) acertos nos casos com 2 canais.Entre os examinadores, na abertura não conservadora obteve-se Kappa = 0,456 e, na conservadora, Kappa=0,629, determinando concordância moderada. Conclusão:conforme os resultados, as aberturas coronárias triangulares não conservadoras levam a um percentual maior de acertos na localização dos canais de incisivos inferiores do que as aberturas conservadoras ovais, sendo essa diferença estatisticamente significativa (p<0,05)