Cone beam computed tomographic evaluation of a maxillary alveolar ridge reconstruction with iliac crest graft and implants

The present article discusses an atrophic maxilla reconstruction with iliac crest bone block and particulate grafts and dental implants. Onlay block grafts were used to restore bone volume of the anterior maxilla, whereas bilateral sinus floor augmentation was performed using a particulate graft. Ten months after the grafting surgery, 9 dental implants were placed to rehabilitate the case. Results of a 7-year follow-up were obtained clinically and by cone beam computed tomographic images.     

In vivo assessment of DNA damage induced in oral mucosa cells by fixed and removable metal prosthodontic appliances

Given long-term effect on oral tissues due to contact with dental appliances, the biocompatibility studies of casting alloys are of great importance. It has been previously documented that metal dental appliances, due to corrosion, might induce genotoxic and mutagenic effects in cells. Therefore, the aim of presented study was to examine the genotoxicity of two dental casting alloys (Co-Cr-Mo and Ni-Cr) commonly used in fixed and removable prosthodontic appliances that are in contact with the oral epithelium for 5 years or more. For that purpose, 55 age-matched subjects were included in the study; 30 wearers of prosthodontic appliances and 25 controls. Buccal cells of oral mucosa were collected and processed for further analysis. The cell viability has been assessed by trypan blue exclusion test, while genotoxic effect of metal ions on DNA in oral mucosa cells was studied by use of alkaline comet assay. Results have shown significantly higher comet assay parameters (tail length and percentage DNA in the tail) in the group wearing metal appliances. Both subjects with Co-Cr-Mo alloy and Ni-Cr alloy showed significantly higher comet assay parameters when compared with controls. It has been confirmed that metal ions released by the two base metal dental casting alloys examined in this study, might be responsible for DNA damage of oral mucosa cells. Therefore, the results of this study emphasize the importance of the in vivo evaluation of dental materials with respect to their genotoxicity, which is of major importance to ensure long-term biocompatibility.     

Cone Beam Computed Tomographic Measurement of Maxillary Central Incisors to Determine Prevalence of Facial Alveolar Bone Width ≥2 mm

Background: The initial thickness of maxillary bone has significant impact on the responding level of facial bone and soft tissue after extraction and immediate implant placement. A prevailing notion is that following implant placement in fresh extraction sites, at least 2 mm of facial bone is needed to prevent soft tissue recession, fenestration, and dehiscence. Purpose: The purpose of this study was to use cone beam computed tomography (CBCT) to measure horizontal width of facial alveolar bone overlying healthy maxillary central incisors and to determine prevalence of bone thickness ≥2 mm. Materials and Methods: Tomographic data from 101 randomly selected patients were evaluated by two independent observers. Assessments were made of facial bone width at levels 1.0 to 10.0 mm apical to the bone crest. Results: Healthy maxillary central incisors (n = 202) were measured from 101 patient scans. The percent of teeth with facial bone ≥2 mm at levels 1, 2, 3, 4, and 5 mm from the bone crest was 0, 1.5, 2.0, 3.0, and 2.5%, respectively. Overall mean thickness of the bone was 1.05 mm for right and left central incisors combined. The range of individual measurements for all levels was 0 to 5.1 mm. The occurrence of ≥2 mm thickness bone measurements increased with increasing depth. However, mean widths observed at levels 6 to 10 mm from the crest ranged only 1.0 to 1.3 mm because of apparent fenestration occurrence (0 mm bone) in approximately 12% of teeth. Overall, no significant differences in bone thickness were found between ethnic, gender, age, or scan groups. Conclusions: Using CBCT, occurrences of ≥2 mm maxillary facial alveolar bone were found on no more than 3% of root surfaces 1.0 to 5.0 mm apical to the bone crest in this sample of maxillary central incisors. The study evidenced prevalence of a thin facial alveolar bone (<2 mm) that may contribute to risk of facial bone fenestration, dehiscence, and soft tissue recession after immediate implant therapy.     

Methylparaben concentration in commercial Brazilian local anesthetics solutions

Objective

To detect the presence and concentration of methylparaben in cartridges of commercial Brazilian local anesthetics.

Material and methods

Twelve commercial brands (4 in glass and 8 in plastic cartridges) of local anesthetic solutions for use in dentistry were purchased from the Brazilian market and analyzed. Different lots of the commercial brands were obtained in different Brazilian cities (Piracicaba, Campinas and São Paulo). Separation was performed using high performance liquid chromatography (HPLC) with UV-Vis detector. The mobile phase used was acetonitrile:water (75:25 - v/v), pH 4.5, adjusted with acetic acid at a flow rate of 1.0 ml.min^-1.

Results

When detected in the solutions, the methylparaben concentration ranged from 0.01% (m/v) to 0.16% (m/v). One glass and all plastic cartridges presented methylparaben.

Conclusion

1. Methylparaben concentration varied among solutions from different manufacturers, and it was not indicated in the drug package inserts; 2. Since the presence of methylparaben in dental anesthetics is not regulated by the Brazilian National Health Surveillance Agency (ANVISA) and this substance could cause allergic reactions, it is important to alert dentists about its possible presence.