Assessment of image quality and exposure parameters of an intraoral portable X-rays device.

OBJECTIVE:: To evaluate the exposure parameters, radiation protection, absorbed dose and radiographic image quality of the DIOX® intraoral portable radiography device. METHODS:: The exposure parameters were measured using the Xi UNFORS detector. Operator exposure to secondary radiation was measured using the 1800cc ionization chamber coupled to the electrometer. The absorbed dose (D) in the patient was calculated using TLD-100H positioned in the Alderson RANDO anthropomorphic simulator. The quality of the radiographic digital image was assessed by comparing radiographic images obtained from two conventional devices (CS 2200®, Carestream Health; Heliodent plus®, Sirona Dental Systems GMbH) with the radiological simulator of the upper molar region RMI (Radiation Measurements Instruments), using three acquisition sensors: Kodak RVG 5000® and Kodak PSP®, Eastman Kodak Company, Rochester, NY; EVO Micro Image®, Brazil. RESULTS:: The DIOX intraoral portable radiographic device demonstrated reliability in relation to the performance of the standard evaluated parameters, except for the diameter of the radiation field (5.8 mm) less or greater. No evidence of device head radiation was detected. The Pb lead protection of the apparatus attenuates the secondary radiation, thus protecting the operator. However, it was observed that the region of the operator's gonads was the most exposed during the measurements. In the Alderson RANDO anthropomorphic simulator, the highest value of D was in the region corresponding to the submandibular and lingual glands of the left side (0.568 mGy). The image quality of the DIOX portable radiographic apparatus presented quality standards equivalent to those produced by the two conventional radiographic devices. CONCLUSION:: The DIOX intraoral portable radiography device demonstrated reliability in relation to the quality control and radioprotection criteria, according to international standards. Results obtained demonstrated the safe use of the DIOX intraoral portable radiography device and indicated the need for debate and change in international sanitary oversight standards regarding the use of portable XR devices in dentistry.

Oral Streptococci Biofilm Formation on Different Implant Surface Topographies.

The establishment of the subgingival microbiota is dependent on successive colonization of the implant surface by bacterial species. Different implant surface topographies could influence the bacterial adsorption and therefore jeopardize the implant survival. This study evaluated the biofilm formation capacity of five oral streptococci species on two titanium surface topographies. In vitro biofilm formation was induced on 30 titanium discs divided in two groups: sandblasted acid-etched (SAE- n = 15) and as-machined (M- n = 15) surface. The specimens were immersed in sterilized whole human unstimulated saliva and then in fresh bacterial culture with five oral streptococci species: Streptococcus sanguinis, Streptococcus salivarius, Streptococcus mutans, Streptococcus sobrinus, and Streptococcus cricetus. The specimens were fixed and stained and the adsorbed dye was measured. Surface characterization was performed by atomic force and scanning electron microscopy. Surface and microbiologic data were analyzed by Student's t-test and two-way ANOVA, respectively (P < 0.05). S. cricetus, S. mutans, and S. sobrinus exhibited higher biofilm formation and no differences were observed between surfaces analyzed within each species (P > 0.05). S. sanguinis exhibited similar behavior to form biofilm on both implant surface topographies, while S. salivarius showed the lowest ability to form biofilm. It was concluded that biofilm formation on titanium surfaces depends on surface topography and species involved.

Impact of human maxillary sinus volume on grafts dimensional changes used in maxillary sinus augmentation: a multislice tomographic study.

PURPOSE: To assess the influence of complete maxillary sinus volume on the dimensional changes of different grafts used in maxillary sinus lift. MATERIALS AND METHODS: Analysis of 50 surgical procedures of maxillary sinus lift performed on 43 subjects using different grafting materials: fresh frozen allogenic particulated bone (11), hydroxyapatite (Endobon(®)) (17), 60% hydroxyapatite + 40% beta-tricalcium phosphate (Bone Ceramic(®)) (12) and Bone Ceramic(®) + Emdogain(®) (10). One hundred and fifty multislice tomographic images of the maxillary sinus were obtained using the software Syngo CT 2011 A VOLUME, measuring complete maxillary sinus volume (T0) and dimensional changes of different graft materials during periods of 15 days (T1) and 180 days (T2). The factor studied was the influence of maxillary sinus volume on the dimensional changes of different graft materials used in maxillary sinus lift in patients with posterior edentulism. Data obtained were assessed using the Student's t-test and Pearson's correlation coefficient. RESULTS: No correlation (r 0.112) between the total maxillary sinus volume and the dimensional changes of the different graft materials used in this study was observed (P > 0.05). CONCLUSION: This study demonstrated that there is no sufficient evidence to support the thesis that the volume of the maxillary sinus influences the contraction of the grafts, at least on sample or the biomaterials evaluated in this cohort study.

Volumetric dimensional changes of autogenous bone and the mixture of hydroxyapatite and autogenous bone graft in humans maxillary sinus augmentation. A multislice tomographic study.

PURPOSE: This multislice tomographic study evaluated the dimensional changes after maxillary sinus augmentation using autogenous bone or a mixture of hydroxyapatite and autogenous bone. MATERIALS AND METHODS: Ten selected patients, requiring a bilateral maxillary sinus augmentation, were divided, in a split mouth, design as follows: control group (CG n = 10 sinus grafted with autogenous bone) and test group (TG, n = 10 sinus grafted with a mixture of hydroxyapatite and autogenous bone at 80 : 20 w/w). Follow a healing period of 15 and 180 days, computed tomography (CT) measurements were taken by two blinded and calibrated examiners to verify the volumetric dimensional changes of the both groups. RESULTS: The interobserver agreement obtained ranged from good to excellent for both groups. Both groups presented significant dimensional changes after 180 days period healing (P < 0.05). The volumetric reduction in test group was lower (25.87%) when compared with the CG (42.30%) (P < 0.05). CONCLUSION: The both graft materials improved the bone volumetric ability to anchorage a dental implant. Moreover, the mixture of HA and autogenous bone graft showed lower degree of resorption and higher dimensional stability when compared with autogenous bone graft alone, at least at 180 days of healing. The CT exam protocol should be used as an important tool to measure bone grafts volumetric alterations.

Absorbed radiation doses during tomographic examinations in dental implant planning: a study in humans.

OBJECTIVE: The aim of this human study was to evaluate the radiation doses in the buccal cavity and face, during panoramic, spiral conventional tomography, and helicoidal computerized tomography exams. MATERIAL AND METHODS: Lithium fluoride TL detectors (TLD-100) were placed on the skin at anatomic points such as parotid glands, submandibular glands, thyroid glands, and crystalline to assess the skin entrance dose in 19 patients who were to undergo dental implant surgery. RESULTS: In the panoramic exam, maximum doses were observed near the parotid glands at 1.57 (±18%) mGy on the right and 1.89 (±18%) mGy on the left. In the spiral conventional tomography exam, the maximum dose was 4.41 (±21%) mGy near the right and left parotid glands, whereas near the right or left submandibular glands, the maximum doses reached 40.7 (±18%) mGy. In the helicoidal computerized tomography for mandibular and maxilla exams, the maximum dose was 40.9 (±15%) mGy near the parotid glands and 41.0 (±18%) mGy near the submandibular glands. Near the thyroid and eye lens, doses were lower than 0.23 (±21%) in all exams. CONCLUSION: Regardless of the exam target area, the submandibular and parotid glands represented the most irradiated organs. This data suggests that efforts should be made by professionals to improve and optimize methods in order to reduce doses without losing the information necessary for treatment planning.

An unusual glycoform of human salivary mucin MG2.

Since in a previous study we encountered a subject with an unusual split MG2 banding pattern, the aim of this study was to investigate the molecular basis of this observation. Submandibular/sublingual secretion was collected under resting and stimulated conditions and examined on Western blots probed with anti-MG2 antibodies or on gels stained with periodic acid-Schiff reagent. Genomic DNA was isolated and the N-, tandem repeat (TR), and C-terminal regions of MUC7 were amplified by PCR since MG2 is known to display a genetic polymorphism. Although the typical appearance of MG2 on blots and gels is a single 180 kDa band, salivary secretions from the subject exhibited doublet immunoreactive bands of approximately 180 and 125 kDa. Additionally, under resting conditions the 180 kDa band was predominant whereas upon stimulation the 125 kDa band became predominant. Genomic DNA analysis showed that MUC7 in the individual with split MG2 bands was not truncated and that the MUC7 genotype in this individual was (6/6) where both alleles encoded six TRs. The MG2 split banding pattern observed in this subject was not derived from proteolytic degradation of this salivary mucin in whole saliva or from genetic polymorphism. The expression of two isoforms of MG2 could in principle improve or reduce the activity of this key component of the oral host defense system.

Genetic polymorphism of MUC7 in individuals with aggressive or chronic periodontitis.

Individuals with periodontitis exhibit differential expression of mucin-glycoprotein-2 (MG2), a protein encoded by the MUC7 gene. It is well known that MG2 exerts bactericidal activity as well as exhibiting genetic polymorphism involving a variable number of tandem repeats (VNTR). In the present study, we assessed the distribution of allelic variants of the MUC7 gene in 22 individuals with aggressive periodonitis, 68 with chronic periodonitis, and 87 without periodonitis. Oral mucosal cells were collected, the DNA was extracted, and specific primers were used to amplify the region encoding the MUC7 tandem repeats (TRs). Polymerase chain reaction products were subjected to electrophoresis and analyzed on polyacrylamide gels stained with silver nitrate. Although the percentage distribution of homozygosity (6-6TR) and heterozygosity (5-6TR) showed variation among the groups, the observed differences were not statistically significant (P > 0.05; Fisher's Exact Test). The present results indicate that the expression of different numbers of TRs in this salivary mucin in the oral environment does not interfere with the etiopathogenesis of aggressive or chronic periodontitis.

Complications in surgical removal of impacted mandibular third molars in relation to flap design: clinical and statistical evaluations.

OBJECTIVE: The extraction of an impacted mandibular third molar may result in periodontal complications on the distal surface of the adjacent second molar. The purpose of this study was to compare the influence of three full-thickness flaps on the periodontal healing of the adjacent second molar after extraction of impacted mandibular third molars. METHOD AND MATERIALS: Forty-five volunteers with bilateral impaction of the mandibular third molars were selected. Each patient was randomly assigned to one of three groups: group A (envelope flap modified by Thibauld and Parant), group B (Laskin triangular flap), and group C (envelope flap modified by Laskin). The periodontal health of the second molars was evaluated at 3, 6, 12, and 24 months after surgery via clinical measurements. RESULTS: After 21 days, there was no correlation between postoperative complications (such as edema and alveolitis) and flap design. However, there was a statistically significant reduction of pocket probing depth (PPD) and increase of clinical attachment level (CAL) in group B compared to the other groups (P<.05) 24 months after surgery. CONCLUSION: The effect of the type of flap used for mandibular third molar surgery on the periodontal status of the second molars as well as the factors that influence this outcome remains uncertain. Regardless of the flap design, the periodontal conditions of the adjacent second molar deteriorated after 12 and 24 months. The decision to use a certain type of flap should be based on the surgeon's preference.

Periodontal abscess during supportive periodontal therapy: a review of the literature.

AIM: The aim of this review is to present the current status of the occurrence and management of a periodontal abscess during supportive periodontal therapy (SPT). BACKGROUND: A periodontal abscess depicts typical features and has been described in patients under SPT in clinical trials. Common periodontal pathogens have been observed in this lesion and some etiologic factors may be responsible for its recurrence. This condition can be isolated or associated with factors that can change the prognosis of affected teeth. REVIEW RESULTS: Although it has been frequently noticed in untreated periodontitis, the periodontal abscess can also occur in patients under SPT and has been regarded as one of the possible complications of SPT. Patients with a high susceptibility to periodontal disease lost more teeth than those with a healthy periodontium. CONCLUSION: Early diagnosis and appropriate intervention for periodontal abscesses in patients under SPT are extremely important for the management of the periodontal abscess since this condition can lead to loss of the involved tooth. A single case of a tooth diagnosed with periodontal abscess that responds favorably to adequate treatment does not seem to affect its longevity. CLINICAL SIGNIFICANCE: An accurate diagnosis and adequate treatment can preserve the longevity of affected teeth.

Gingival overgrowth in renal transplant subjects medicated with tacrolimus in the absence of calcium channel blockers.

BACKGROUND: The results from reports analyzing the occurrence of gingival overgrowth (GO) induced by tacrolimus are controversial. In addition, the role of pharmacological and periodontal variables on the development and severity of GO have not been well-established. Therefore, the aim of the present study was to determine the effect of potential risk variables for GO in a Brazilian population comprising renal transplant recipients medicated with tacrolimus in the absence of calcium channel blockers. MATERIALS AND METHODS: Demographic, pharmacological, and periodontal data, recorded from 125 subjects selected to participate in the study, was analyzed with the use of the independent sample t test, the chi-squared statistic, or Mann-Whitney test. The effects of risk variables on GO scores were subsequently examined using multivariate regression analysis and general linear model. RESULTS: The prevalence of clinically significant GO (> or =30%) in the study population was of 7.25%. These subjects showed greater averages of plaque scores (P=0.0043) as well as papillary bleeding index (P=0.0026) when compared to subjects with GO <30%. Papillary bleeding index, time since transplant and azathioprine dosage were significant in the univariate and multivariate models (adjusted R=43.8%), whereas plaque index was significant only in the univariate model. CONCLUSIONS: This study revealed that, in the absence of calcium channel blockers, gingival inflammation, represented by the papillary bleeding index, was a variable associated with Tcr-induced GO, indicating the importance of periodontal maintenance of subjects under Tcr immunosuppressive regimens.

Nitric oxide levels in saliva increase with severity of chronic periodontitis.

The aims of this study were to compare nitric oxide (NO) levels in stimulated whole saliva from individuals with and without generalized chronic periodontitis (GCP), and to evaluate correlations between these levels with a clinical diagnostic parameter. According to specific criteria, 30 individuals were divided into three groups: one comprising individuals without periodontitis (GC), a second comprising individuals with moderate GCP (GM), and a third comprising individuals with advanced GCP (GA). Samples were collected and NO levels measured. NO in the GCP group (GM: 7.78 microM; GA: 15.79 microM) was higher than in the GC group (5.86 microM). NO levels in the GA group were significantly higher (P < 0.0001) than in the GC group, and could also differentiate (P < 0.0001) the moderate and advanced forms of the disease. In addition, positive correlations between NO level and the number of teeth with a probing depth of > or = 4 mm (r = 0.54) and > or = 7 mm (r = 0.68) were observed. In conclusion, NO levels are elevated in individuals with GPC and are correlated with a periodontal clinical parameter. These results reveal that this form of periodontal disease and its severity are related to salivary nitrite concentration, indicating that NO may serve as a potential biological marker for detection and/or monitoring of GCP.