Validity of multislice computerized tomography for diagnosis of maxillofacial fractures using an independent workstation

OBJECTIVE: The purpose of this study was to demonstrate the sensitivity and specificity of multislice computerized tomography (CT) for diagnosis of maxillofacial fractures following specific protocols using an independent workstation. STUDY DESIGN: The study population consisted of 56 patients with maxillofacial fractures who were submitted to a multislice CT. The original data were transferred to an independent workstation using volumetric imaging software to generate axial images and simultaneous multiplanar (MPR) and 3-dimensional (3D-CT) volume rendering reconstructed images. The images were then processed and interpreted by 2 examiners using the following protocols independently of each other: axial, MPR/axial, 3D-CT images, and the association of axial/MPR/3D images. The clinical/surgical findings were considered the gold standard corroborating the diagnosis of the fractures and their anatomic localization. The statistical analysis was carried out using validity and chi-squared tests. RESULTS: The association of axial/MPR/3D images indicated a higher sensitivity (range 95.8%) and specificity (range 99%) than the other methods regarding the analysis of all regions. CONCLUSION: CT imaging demonstrated high specificity and sensitivity for maxillofacial fractures. The association of axial/MPR/3D-CT images added important information in relationship to other CT protocols.     

Effect of mechanical cycling on the flexural strength of densely sintered ceramics.

OBJECTIVES: The aim of this study was to evaluate the effect of mechanical cycling on the biaxial flexural strength of two densely sintered ceramic materials. METHODS: Disc shaped zirconia (In-Ceram Zirconia) and high alumina (Procera AllCeram) ceramic specimens (diameter: 15 mm and thickness: 1.2 mm) were fabricated according to the manufacturers' instructions. The specimens from each ceramic material (N=40, n=10/per group) were tested for flexural strength either with or without being subjected to mechanical cycling (20,000 cycles under 50 N load, immersion in distilled water at 37 degrees C) in a universal testing machine (1 mm/min). Data were statistically analyzed using two-way ANOVA and Tukey's test (alpha=0.05). RESULTS: High alumina ceramic specimens revealed significantly higher flexural strength values without and with mechanical cycling (647+/-48 and 630+/-43 MPa, respectively) than those of zirconia ceramic (497+/-35 and 458+/-53 MPa, respectively) (p<0.05). Mechanical cycling for 20,000 times under 50 N decreased the flexural strength values for both high alumina and zirconia ceramic but it was not statistically significant (p>0.05). SIGNIFICANCE: High alumina ceramic revealed significantly higher mean flexural strength values than that of zirconia ceramic tested in this study either with or without mechanical cycling conditions.     

Pain experienced by patients during periodontal maintenance

BACKGROUND: The aims of this study were to determine: 1) the degree of pain experienced by patients during probing and debridement; 2) whether the treating hygienists could estimate the degree of pain experienced by the patients; and 3) whether the patients' pain responses could be predicted by factors such as the patients' age, gender, number of residual periodontal lesions, and answers to a questionnaire on dental anxiety. METHODS: Prior to periodontal maintenance procedures, two groups of 20 adult patients to be treated by two hygienists completed an anxiety questionnaire. Subsequently, measurements of probing depths were performed, followed by pain ratings by each patient using a visual analog scale (VAS). The hygienists also completed a VAS, estimating the pain level they perceived their patient to have experienced. The same protocol was repeated for instrumentation (debridement). RESULTS: Most patients showed low pain responses to both probing and instrumentation. However, using an arbitrary threshold of VAS > or = 40 mm, 20% to 33% of the patients had a significant pain experience. The hygienists were quite accurate in their relative estimates of their patients' pain experiences. Regression analyses disclosed that significant portions of the pain responses could be predicted by the patients' answers to one of the dental anxiety questions. CONCLUSIONS: Recognition of patients who are likely to experience significant pain during periodontal treatment may be facilitated by the use of one question on dental anxiety. During treatment, the ability to gauge and respond to patients' pain experiences would seem to be an important component of a therapist's clinical skills.     

Prospective evaluation of implants connected to teeth

PURPOSE: This prospective clinical trial examined the effect on teeth and implants when rigidly or non-rigidly connected in a cross-arch model. MATERIALS AND METHODS: Thirty patients received 2 implants, 1 on each side of the mandible, and were restored with 3-unit fixed partial dentures connected either rigidly or non-rigidly to an abutment tooth. Patients were followed for at least 5 years post-restoration. RESULTS: Repeated-measures analysis revealed no significant difference in crestal bone loss at implants (rigid versus non-rigid methods). An overall significant difference (P < .001) was found comparing methods for teeth. Paired t tests revealed no significant differences in crestal bone levels for implants or teeth at the 5-year recall. Kaplan-Meier methods and the Cox proportional hazards model showed no differences between attachment methods with regard to success based on survival and bone loss criteria. During the 5-year recall period, 1 implant (rigid side) was removed. Four implants developed bone loss greater than 2 mm during the course of this trial. One tooth on the rigid side and 2 teeth on the non-rigid side had greater than 2 mm of crestal bone loss and were removed secondary to fractures. In all, 5 abutment teeth were removed, all of which had been treated with root canal therapy and fractured at the interface of the post within the tooth. There was no clear relationship of tooth fracture to attachment. Repeated-measures analysis of mobility values revealed no significant changes over the time course of this study, and paired t tests revealed no statistically significant differences between implants for mobility. Repeated-measures analysis and paired t tests for probing depth revealed no significant changes over the time course of this study. There were no significant differences in soft tissue indices for either attachment method. The percentage of patients who had measurable intrusion was 66% for the non-rigid group, and 44% for the rigid group; 25% of the non-rigid teeth had greater than 0.5 mm intrusion, compared with 12.5% for the rigid group. For the 2 time periods evaluated, there was no significant increase in intrusion over time. The non-rigid-side implant required more nonscheduled visits to treat problems than the rigid implant and the teeth. Discussion: Most patients were treated successfully with rigid or non-rigid attachment of implants to teeth. CONCLUSION: The high incidence of intrusion and non-scheduled patient visits suggest that alternative treatments without connecting implants to teeth may be indicated.     

Presence of mutans streptococci and Candida spp. in dental plaque/dentine of carious teeth and early childhood caries

This study determined the presence of mutans streptococci and Candida spp. in supragingival dental plaque and infected dentine of caries-free children, with early childhood caries and caries. Pooled samples of dental plaque and infected dentine were collected from 56 children aged 1-5 years, which were divided into 3 groups: early childhood caries (ECC); caries and caries-free. Infected dentine was collected in ECC and caries groups to compare the frequency of these microorganisms in the collected sites. The samples were inoculated in SB20 and SA medium, for mutans streptococci and Candida spp., respectively, and incubated at 37 degrees C for 48 h. Colony growth was verified and the identification was performed by biochemical tests and CHROMagar Candida. Fisher's test or chi-square (chi(2)) were applied (p=0.05). The more prevalent species were S. mutans and Candida albicans in ECC (85.4% and 60.4%, respectively), independently of the sample site. S. mutans only was significantly associated with carious teeth, whether in early childhood caries or not. However, the frequency of C. albicans in ECC was higher when compared to caries and caries-free groups. There is a significant association between the presence of C. albicans and early childhood caries.     

Ultrastructural and microbiological analysis of the dentin layers affected by caries lesions in primary molars treated by minimal intervention

PURPOSE: The purpose of this in vivo study of primary teeth was to analyze the ultrastructure and microbiology of dentin layers affected by caries lesions before and after restorations with resin-modified glass ionomer. METHODS: Samples of carious dentin from primary teeth removed prior to restoration placement (baseline-0 day) were compared with samples taken after 30 and 60 days. Dentin from 8 primary molars was analyzed by scanning electron microscopy (SEM) and dentin from 22 primary molars was examined microbiologically to compare bacteria (total of viable counts, Streptococcus spp, Streptococcus mutans, Lactobacillus spp, and Actinomyces spp) before and after treatment (30 and 60 days). RESULTS: Baseline caries samples had enlarged dentinal tubules with bacteriol invasion. SEM samples after treatment suggest better tissue organization, with more compact collagen fibers arrangement and narrower dentinal tubules. The number of bacteria decreased in all samples at both 30 (98%) and 60 (96%) days, with all bacteria species showing similar trends. CONCLUSIONS: The minimal intervention approach is very effective to promote beneficial changes in the lesion environment and favorable conditions for the healing process in primary teeth.     

Exploring bacterial diversity of endodontic microbiota by cloning and sequencing 16S rRNA

Introduction

The characterization of microbial communities infecting the endodontic system in each clinical condition may help on the establishment of a correct prognosis and distinct strategies of treatment. The purpose of this study was to determine the bacterial diversity in primary endodontic infections by 16S ribosomal-RNA (rRNA) sequence analysis.

Methods

Samples from root canals of untreated asymptomatic teeth (n = 12) exhibiting periapical lesions were obtained, 16S rRNA bacterial genomic libraries were constructed and sequenced, and bacterial diversity was estimated.

Results

A total of 489 clones were analyzed (mean, 40.7 ± 8.0 clones per sample). Seventy phylotypes were identified of which six were novel phylotypes belonging to the family Ruminococcaceae. The mean number of taxa per canal was 10.0, ranging from 3 to 21 per sample; 65.7% of the cloned sequences represented phylotypes for which no cultivated isolates have been reported. The most prevalent taxa were Atopobium rimae (50.0%), Dialister invisus, Prevotella oris, Pseudoramibacter alactolyticus, and Tannerella forsythia (33.3%).

Conclusions

Although several key species predominate in endodontic samples of asymptomatic cases with periapical lesions, the primary endodontic infection is characterized by a wide bacterial diversity, which is mostly represented by members of the phylum Firmicutes belonging to the class Clostridia followed by the phylum Bacteroidetes.     

Assessing the quality of clinical and administrative data extracted from hospitals: the General Medicine Inpatient Initiative (GEMINI) experience

ObjectiveLarge clinical databases are increasingly used for research and quality improvement. We describe an approach to data quality assessment from the General Medicine Inpatient Initiative (GEMINI), which collects and standardizes administrative and clinical data from hospitals.MethodsThe GEMINI database contained 245 559 patient admissions at 7 hospitals in Ontario, Canada from 2010 to 2017. We performed 7 computational data quality checks and iteratively re-extracted data from hospitals to correct problems. Thereafter, GEMINI data were compared to data that were manually abstracted from the hospital’s electronic medical record for 23 419 selected data points on a sample of 7488 patients.ResultsComputational checks flagged 103 potential data quality issues, which were either corrected or documented to inform future analysis. For example, we identified the inclusion of canceled radiology tests, a time shift of transfusion data, and mistakenly processing the chemical symbol for sodium (“Na”) as a missing value. Manual validation identified 1 important data quality issue that was not detected by computational checks: transfusion dates and times at 1 site were unreliable. Apart from that single issue, across all data tables, GEMINI data had high overall accuracy (ranging from 98%–100%), sensitivity (95%–100%), specificity (99%–100%), positive predictive value (93%–100%), and negative predictive value (99%–100%) compared to the gold standard.Discussion and ConclusionComputational data quality checks with iterative re-extraction facilitated reliable data collection from hospitals but missed 1 critical quality issue. Combining computational and manual approaches may be optimal for assessing the quality of large multisite clinical databases.