Effect of aperture size on irradiance of LED curing units.

OBJECTIVE: The aim of this study was to evaluate the light output from LED-curing units measured according to the current ISO standards. The effect of aperture size on irradiance was also evaluated. METHOD: The irradiance of light-curing units and the depths of cure of composites exposed to these units were determined using the methods outlined in ISO standards, ISO/TS10650 and ISO 4049, respectively. The irradiance measured through two different sized apertures was also measured. RESULTS: The irradiance measured with an aperture was greater than that without an aperture. For each light-curing unit and material, there was a linear relationship between the depth of cure and the logarithm of the amount of exposure, which is defined as the product of the irradiance and irradiation time. The correlation coefficients of these linear relationships, using data obtained from the different units was only moderate when the irradiance was measured without an aperture. The correlations improved with decreasing aperture size. SIGNIFICANCE: Since the irradiance is affected by the angular aperture of the light guide and the size of the mold for measuring depth of cure of resin in ISO 4049 is 4-mm diameter, the irradiance through a 4-mm aperture should be used in the determination of the relationship between depth of cure and light exposure.     

AICRG, Part IV: Patient satisfaction reported for Ankylos implant prostheses

PROBLEM: Although many maxillary dentures exhibit sufficient retention and stability for patients to adapt well to them, mandibular dentures present a major challenge. The introduction of the endosseous dental implant provided the opportunity for the patient to have esthetic replacements (implant prostheses) that were retentive and stable for all missing natural teeth. METHOD: This paper reports on the satisfaction of over 470 patients with implant prostheses fabricated using a new and innovative implant design (Ankylos, Dentsply-Friadent, Mannheim, Germany). RESULTS: A total of 1500 Ankylos implants were placed, restored, and followed for 3 to 5 years. Patients were asked to respond to a series of questions related to their satisfaction with their new replacements for missing natural teeth. A total of 95.6% of the patients rated chewing ability with Ankylos prosthesis as excellent to good; 92.2% indicated a significant improvement in their ability to chew; 92.6% reported overall clinical function much better than conventional dentures; 99.1% indicated that speech had improved or was not changed; 96.3% indicated hot and cold foods tasted better; 98.8% indicated no pain or discomfort during clinical function; 99.4% liked their new implant prosthesis; 98.0% would seek implant-prostheses treatment again, if necessary; 99.1% would recommend implant prostheses to friends and relatives; and 98.8% indicated the advantages of Ankylos prostheses far exceeded any disadvantages that may exist. CONCLUSIONS: Patients indicated that they (1) were highly satisfied with the final results of the replacements for their natural teeth that were retained or supported by this new implant design, (2) would not hesitate to recommend this form of treatment to their friends and relatives, and (3) would not hesitate to seek the same treatment again if necessary in the future.     

Dental caries in HIV-seropositive women

Reports that compare dental caries indices in HIV-seropositive (HIV+) subjects with HIV-seronegative (HIV-) subjects are rare. The objective of this study was to determine if there was an association between HIV infection and dental caries among women enrolled in the Women's Interagency HIV Study. Subjects included 538 HIV+ and 141 HIV- women at baseline and 242 HIV+ and 66 HIV- women at year 5. Caries indices included DMFS and DFS (coronal caries) and DFSrc (root caries). Cross-sectional analysis of coronal caries data revealed a 1.2-fold-higher caries prevalence among HIV+ women compared with HIV- women. Longitudinally, DMFS increased with increasing age and lower average stimulated salivary volume. Root caries results were not significant except for an overall increased DFSrc associated with smoking. Anti-retroviral therapy was not identified as a risk factor for dental caries.     

Locally applied isosorbide decreases bone resorption in experimental periodontitis in rats

BACKGROUND: The role of nitric oxide (NO) on bone metabolism is controversial, since it can either stimulate bone formation or resorption. We investigated the effect of local administration of the NO donor isosorbide in an experimental periodontal disease model. METHODS: Wistar rats were subjected to a ligature placement around the cervix of the right second upper molar and were sacrificed after 11 days. Alveolar bone loss was measured in one quadrant as the sum of the distances between the cuspid tip and the alveolar bone along the axis of each molar root, which was subtracted from the contralateral side, used as unligated control. The semiquantitative histopathological scale of the periodontium was based on cell infiltration and alveolar bone and cementum integrity. Groups were treated with a gel containing 1% or 5% isosorbide applied to the vestibular side of the molar gingiva 1 hour before the placement of the ligature and then twice daily until sacrifice. Controls included one group subjected to periodontitis and no treatment (NT) and another that received the gel containing just the vehicle (V). RESULTS: The application of the vehicle gel produced an increase of the alveolar bone resorption, without altering the inflammatory changes, compared to the NT group. The 5% isosorbide produced a significant reduction of the alveolar bone resorption, compared to V and NT. This reduction was confirmed by histological analysis, showing less inflammatory cell infiltration and preservation of the cementum and the alveolar process. CONCLUSION: Local application of isosorbide reduces alveolar bone resorption in experimental periodontal disease in rats, suggesting a local anti-inflammatory effect of isosorbide.     

Sentiments expressed in relation to tooth loss: a qualitative study among edentulous Saudis

Purpose

The objective was to explore and gain insight into the sentiments surrounding tooth loss in a group of edentulous Saudis.

Materials and Methods

Using a qualitative methodology, 44 edentulous patients who were receiving complete denture treatment were interviewed in private, in the Arabic language. Interviews were tape recorded and semistructured, following a list of predetermined and piloted topics, but dialogue also took place, with the freedom for both interviewer and interviewee to explore areas of interest. All recordings were transcribed, translated into English, and interpreted independently by two members of the team to identify the core themes associated with tooth loss.

Results

The mean age of participants was 58.9 years (range 35 to 72 years), and they had been edentulous for a mean of 7.1 years (range 3 months to 22 years). The main themes related to tooth loss were unqualified acceptance, inevitability with old age, behavior changes with respect to eating comfort, aged appearance, self-responsibility, positively perceived benefits, high prosthetic expectations and reduced level of denture satisfaction, and some need for privacy.

Conclusion

The lack of any outward indication that participants experienced bereavement suggests that outlook on life can influence the impact of tooth loss. Participants’ unqualified acceptance of their edentulous fate, yet their clear need to “normalize” oral function, reflects a degree of pragmatism toward life events. The strong influence of religion in Saudi society is a possible factor in the sentiments expressed.     

Sealing ability of MTA, Super EBA, Vitremer and amalgam as root-end filling materials

This study evaluated the root-end sealing ability of mineral trioxide aggregate (MTA Angelus), reinforced zinc oxide-eugenol cement (Super EBA), resin-modified glass ionomer (Vitremer) and zinc-free amalgam (GS-80) (control). The root canals of eighty human lower molars were accessed, cleansed, shaped and obturated. Apexes were resected and cavities were prepared. Teeth were divided into 4 groups of 40 cavities, root-end filled with the materials, and immersed in methylene blue for 72 h at 37 degrees C. Roots were then sectioned transversally at each millimeter and evaluated under magnification, observing the dye penetration in each section. Data were evaluated using Kruskal-Wallis test at a 5% level of significance, showing the differences among all materials (p < 0.001). The crescent order of microleakage was MTA < Vitremer < Super EBA < amalgam. Higher leakage levels were observed in the first millimeter sections of amalgam, Vitremer and MTA, when compared with the third millimeter section (p < 0.05).     

Literature survey of apexification in connection with three cases

Endodontic treatment of three non-vital immature teeth is discussed. According Moorrees et al. root formation was in the stage two, six and four respectively. After access to the root canal, removing necrotic pulp and effective chemo-mechanical cleansing, Ca(OH)2 paste was used as a temporary filling material in each case. In two cases after closing the apical opening, permanent obturation was performed with half heated gutta-percha and lateral condensation to obtain a good seal. In one case permanent filling of the canal occurred with gutta-percha and AH26 as a sealer. In the first case two years, in the second case five years after obturation of the root canal with gutta-percha, periapical healing was evident in the control radiograph. In the third case using gutta-percha with AH26 as a sealer after two years new periapical lesion has developed. On the bases of literature data and our experiences in the case of non-vital immature teeth. Ca(OH)2 paste is the best temporary filling material to induce apexification process, and the half heated gutta-percha obturation is the most suitable permanent root filling material.     

Water concentration in self-etching primers affects their aggressiveness and bonding efficacy to dentin

Water is required to ionize acid resin monomers for demineralization of tooth substrates. We tested the null hypothesis that altering the water concentration in two-step self-etching primers has no effect on their aggressiveness and bonding efficacy to dentin. Five experimental self-etching primers were prepared with resin-water-ethanol volume ratios of 9-0-1, 8-1-1, 7-2-1, 5-4-1, and 3-6-1. They were applied to smear-layer-covered dentin, followed by a bonding resin and composite build-ups for microtensile bond testing and TEM examination of tracer penetration. Increasing water concentration from 0-60 vol% improved acidic monomer ionization that was manifested as increasing hybrid layer thickness. However, significantly higher bond strength was observed in the 7-2-1 group, with minimal nanoleakage in the corresponding hybrid layer. When self-etching primers are formulated, a balance must be achieved to provide sufficient water for adequate ionization of the acidic monomers, without lowering the resin concentration too much, to optimize their bonding efficacy to dentin.     

Evaluation of endodontic treatments performed by students in a Brazilian Dental School

The aims of this study were to evaluate the clinical outcomes of root canal treatments performed by final-year students in the Dental School of Piracicaba, State University of Campinas, SP, Brazil, during the year 2000 and to evaluate the success rate of these treatments at follow-ups conducted one and three years later (2001-03). All 579 endodontic treatments performed by final-year students were selected for this investigation. Detailed personal and dental history was obtained from the patient's records. Clinical and radiographic follow-up examinations were performed. For 78.8 percent of the cases, dental caries was recorded as the cause for performing endodontic treatment; for 8.8 percent, prosthetic reasons were given; and for 12.4 percent, failure of the endodontic treatment was the reason. The largest percentage (30.7 percent) of recalled patients was examined after one year; the success rate at this follow-up evaluation ranged from 83 percent to 96 percent depending on the pulp status prior to the root canal treatment. After three years, only 8 percent of treated patients returned; assessment for them revealed a 75.5 percent success rate. Dental caries is still the main reason for endodontic treatment. This level of success of the root canal treatment in a Brazilian dental school is similar to other reports in the literature.