Assessment of the Effect of CO2 Laser Irradiation on the Reduction of Bacteria Seeded on Commercially Available Sandblasted Acid-Etched Titanium Dental Implants: An In Vitro Study.

PURPOSE: To evaluate the capability of carbon dioxide (CO2) laser in reducing Escherichia coli on sandblasted acid-etched (SAE) titanium dental implants. MATERIALS AND METHODS: SAE dental implants were contaminated with E coli, incubated in a sterile bacterial culture medium for 24 hours, and then exposed to CO2 laser (10,600-nm wavelength) in superpulsed waves (SPW) at 1.5, 1.7, and 2 W at 100-Hz frequency and continuous wave (CW) at 1.5, 2, and 2.5 W. The presence of bacteria trapped in the implant surfaces after contamination and decontamination was verified using spectrophotometry. Scanning electron microscopy (SEM) was used to evaluate the topography of laser irradiation. After implant surface contamination was verified, implants were exposed to CO2 laser irradiation, and bacterial growth was measured with spectrophotometry. RESULTS: The control implants showed the highest bacterial growth (100% growth). Implants exposed to laser showed progressive increase in the percentage of decontamination (DC%) corresponding to the higher wattage in the SPW and CW groups. The DC% were 20.4%, 49.6%, and 51.7% in the SPW group at 100 Hz, at 1.5, 1.7, and 2 W of power, respectively. In the CW group, the DC% were 34.3%, 69.9%, and 85.5% at 1.7, 2, and 2.5 W, respectively. Kruskal-Wallis statistical analysis showed a significant difference between the groups (P < .05). In the pulsed mode (100-Hz) group, statistical analysis showed that the DC% of 1.5 W was significantly lower than the 2 W power. In the CW group, statistical analysis showed that the DC% at 1.7 W was significantly lower (P < .05) than with the other treatments. SEM assessment showed craterlike wear damages and accretions to the implant surfaces that increased progressively as the laser wattage increased. CONCLUSION: CO2 laser irradiation failed to completely decontaminate the implant surfaces. SEM analysis demonstrated damage to the top of the dental implant threads at all settings studied. Thus, CO2 laser irradiation may not be the optimal method to decontaminate implants.

Potential surface alteration effects of laser-assisted periodontal surgery on existing dental restorations.

OBJECTIVE: Laser-assisted gingivectomies are performed in proximity to teeth, existing restorations, and implants. In case of accidental exposures, a detrimental surface defect may cause failure. Surface interactions should be evaluated for safety margin determination of certain laser-material combinations. The purpose of this in vitro study was to assess the microscopic and visible effects of CO2, Nd:YAG, and 810-nm diode laser irradiations on various dental materials and tooth tissue. METHOD AND MATERIALS: Study samples were fabricated (10 x 7.5 mm irradiation surface area, 1 mm thickness) from eight material groups (amalgam, base metal, gold, palladium-silver, composite, ceramic, titanium, and extracted tooth slices). Laser irradiations were performed with CO2, Nd:YAG, and 810-nm diode lasers using the manufacturer's recommended settings for gingivectomy at a 45-degree angle for 30 seconds. Irradiated surfaces were evaluated under SEM at 200x and 1,000x magnifications. Standardized photographs were obtained using a camera mount system (10x high-definition macro lens). The SEM images and photographs were correlated to determine surface interactions. RESULTS: Nd:YAG detrimentally affected all metallic materials and tooth structures. CO2 altered amalgam, gold, and palladium-silver slightly, whereas composite, ceramic, and tooth surfaces were detrimentally altered. The 810-nm diode altered amalgam, gold, titanium, palladium-silver, and composite but only gold and palladium-silver surfaces were barely traceable. CONCLUSION: Within the limitations of this in vitro study, surface effects were all instant; therefore, even a short accidental exposure may be destructive in some laser-material combinations. During gingivectomies, CO2 near tooth-colored restorations and Nd:YAG near metallic restorations and implants should be used carefully. The 810-nm diode was found to be safer due to its reversible alterations in only some materials. Further in vivo studies are necessary to clinically apply the outcomes of this study.

Treatment of bisphosphonates-associated osteonecrosis.

This mini-review will focus on the management of a patient with bisphosphonate-associated osteonecrosis (BON). In order to review the subject the authors report a case of a patient with prostate cancer and metastatic bone disease who was treated with zoledronic acid. Prior to cancer the patient was treated with risedronate for osteopenia but had discontinued this treatment when cancer was diagnosed. During the description of each aspect of the case, a discussion of the rationale used for the case management is presented with support of the available literature. Aspects of interest include the diagnosis of BON, the risk factor for BON for this particular patient, the decision making process for the management of acute and long-term oral cavity problems, and the introduction of high intensity laser therapy to help control pain and reduce infection and local bacterial load.

Oral lesions and HIV: an approach to the diagnosis of oral mucosal lesions for the dentist in private practice / Lesões bucais e HIV: uma abordagem ao diagnóstico de lesões da mucosa bucal para o dentista na clínica particular

The diagnosis and treatment of oral mucosal lesions in HIV infected individuals is of importance. Oral lesions are reliable indicators of HIV infection and immunosuppression. They are important for staging HIV disease, they have been used as clinical markers in trials to test drug efficacy, and to determine the correct time for institution of treatment for HIV or prophylaxis against opportunistic infections. For the patients, they can cause pain, loss of taste and severe discomfort, leading to decreased quality of life. In more severe cases, they can disseminate and become life-threatening. Several types of lesions may affect the oral mucosa of HIV infected individuals. Although caused by different etiological agents, these lesions may have similar clinical appearance. They may also look like other oral mucosal lesions not commonly associated with HIV infection. Their correct diagnosis is important so adequate treatment can be prescribed. This article provides information to the dentist in private practice on how to elaborate a differential diagnosis and arrive to a final diagnosis of oral mucosal lesions in HIV infected individuals

Phenotypic identification of mononuclear cells in oral premalignant lesions and cancer by monoclonal antibodies / Identificação fenotípica de células mononucleares nas lesões-orais pré-malignas e cancer por anti-corpos monoclonais

To explore the nature and importance of mononuclear cells of different phenotypes in oral premalignant lesions and oral cancer, we studied biopsy specimens from 21 oral red and/or white lesions (6 hyperkeratosis, 3 mild dysplasia, 4 severe dysplasia and 8 squamous cell carcinoma), using monoclonal antibodies and avidin-biotin-peroxidase complex staining. Peripheral blood samples (PB) from 4 normal subjects and 5 reactive lymph nodes (LN) were used as controls for the technique. T11-positive cells were the predominant phenotype (74-78 por cento) in all cases examined. The T4/T8 ratio in severe dysplasia was significantly lower than that in mild dysplasia (p ó 0.05). These observations support the hypothesis of a role for cellular immune responses in oral premalignant lesions and oral cancer. The predominance of T cells may represent the local expression of immunity against antigens (viral or other). The decreased T4/T8 ratio observed in severe dysplasia may represent a transitory stage of local immunosuppression, which may be of critical importance for the progression into carcinoma. Phenotypic variations in mononuclear cell infiltrates in these conditions could be of diagnostic value