A comparison between in vivo radiographic working length determination and measurement after extraction

The purpose of this study was to compare the difference between the in vivo working length established by viewing a periapical radiograph and the in vitro measurement from the file tip to the apical foramen of the extracted tooth. Twenty-six canals from teeth that had been treatment planned for extraction were accessed under rubber dam isolation. The coronal portion of each canal was flared using Gates Glidden drills, and a K-type file was inserted down the canal until an electronic apex locator indicated that the file had reached the apex. A size 20 K-type file was locked into place with glass ionomer cement at this position. A radiograph was exposed and the tooth was extracted. Each tooth was viewed using a videomicroscope at 30x original magnification, and the distance from the file tip to the most coronal aspect of the major foramen was measured. Six examiners viewed each radiograph and assessed the working length of each canal. Chi(2) analysis of the data revealed a significant difference (p < 0.01) between the estimation of working lengths and the microscopic measurements. The examiners overestimated the distance between the file tip and the apical foramen of the tooth when the file was placed short, and underestimated the distance when the file was placed long. In conclusion, when the file is short it is actually closer to the apical foramen than it appears radiographically; when it is long it is actually longer than it appears radiographically.     

Visual and profilometric wear measurements.

Wear of composites can be estimated by the degree of marginal discrepancy between the prepared cavity wall and the occlusal margins of composites. Such evaluations are done on casts by comparing and rating the marginal discrepancy with those on standard casts. We analyzed the reliability of this technique on metal and stone specimens. These specimens contained grooves of different width and depth. For the visual comparison we used stone casts of machined standards of known groove depth. We measured the depths of the metal specimens with a profilometer and made stone casts of these original specimens. Using the stone casts of the standards, five dentists estimated the unknown groove depths on the remaining stone casts. These estimates were done under standardized conditions and repeated by each dentist on five different occasions. The results showed that visual depth evaluations of die stone specimens underestimated the depths when compared with the values measured with a profilometer on the original metal models. One investigator gave significantly different (p less than 0.05) groove depth estimates at different occasions.     

Dental root agenesis secondary to irradiation therapy in a case of rhabdomyosarcoma of the middle ear

There have been only a few published reports on the dental-facial effects of radiation therapy and the subsequent oral management of these patients. A case involving a 13-year-old black male patient with a history of rhabdomyosarcoma is presented. The patient received 4,050 rads of radiation to the right middle ear when he was 2 years of age. His residual medical and dental difficulties are apparently complications from the initial therapy. Examination of the oral cavity revealed bimaxillary micrognathia and marked loss of vertical dimension. A Class II facial profile with Class I molar relationship was observed. The mandible was thin and hypoplastic, with a small knife-edge alveolar ridge. The remaining eighteen erupted permanent teeth were very mobile, and root development had ceased after only initial formation. All of the teeth except the first permanent molars were extracted, and immediate partial dentures were inserted at the time of surgery. A discussion of therapeutic considerations follows the case report.     

Surface failure of commercial and experimental restorative resins.

A single-pass test was used to study the surface failure of commercial and experimental restorative resins and composites. The surface failure observed for unfilled diacrylate resins was more severe than that seen for an unfilled acrylic resin. Addition of nonsilanated filler to the diacrylate resins increased the resistance to penetration but did not dramatically change the mode of surface failure. The surface failure of the commercial composite resins, which contain silanated filler, was ductile in mode and the resistance to penetration of the diamond slider was the highest of the materials studied. The wear of restorative resins and composites is determined, therefore, by resistance to penetration as well as mode of deformation during sliding.     

Dental care for handicapped children reexamined: I. Dental training and treatment of the handicapped.

1) Training experience is closely related to whether or not handicapped children are treated. If practitioners attended a postgraduate pedodontic training program, or received classroom education or clinical training in the treatment of handicapped children, they are much more likely to treat such patients. (Worth noting is the fact that one fourth of the pedodontists treating handicapped children had not received postgraduate pedodontic training and 20-30 percent reported no training on the treatment of such patients at all.) 2) Slightly less than half of the general practitioners and 96 percent of the pedodontists surveyed report that they currently treat the dental problems of handicapped children. 3) Practitioners currently treating handicapped children report treating more such patients during their dental training and are more likely to feel that they received sufficient exposure to these patients during their training. (Twenty percent of the general practitioners and 53 percent of the pedodontists felt they had sufficient exposure.) 4) Dentists treating handicapped children were more likely to report both classroom education and clinical training about the use of multidisciplinary health manpower in the treatment of their patients, and to report using such personnel as consultants in their dental practice.     

Neutrophil hyper-responsiveness in periodontitis

Peripheral neutrophil hyper-responsiveness in chronic periodontitis leads to excessive reactive oxygen species (ROS) production. We aimed to determine whether neutrophil hyper-responsiveness was constitutive or reactive, and to discover the effect of non-surgical therapy. Peripheral blood neutrophils from patients (n = 19), before and 3 months after therapy, and matched control individuals were Fc gamma-receptor-stimulated with/without priming with P. gingivalis and F. nucleatum. Total and extracellular ROS were determined by luminol/isoluminol chemiluminescence. The high total ROS generation of patients' neutrophils compared with that of control individuals (P = 0.016) continued at a reduced level post-therapy (P = 0.059). Reduced activity post-therapy was also seen with priming. Unstimulated total ROS levels did not differ between patients and control individuals before or after therapy. However, the high unstimulated, extracellular ROS production by patients' neutrophils compared with control individuals (P < 0.05) continued post-therapy and was unaffected by priming. Therapy reduced Fc gamma-receptor-stimulated total ROS production, but not unstimulated extracellular radical release, suggesting that constitutive and reactive mechanisms underlie neutrophil hyper-responsiveness.     

A six-center international study of treatment outcome in patients with clefts of the lip and palate: Part 5. General discussion and conclusions.

Part 5 is the final part of a series of five articles reporting on an international, multicenter clinical audit of treatment outcome for complete UCLP. A number of recommendations for the methodology of future studies is made especially with respect to entry criteria, sample size, assumptions of homogeneity, and the reproducibility and validity of outcome measures. The findings of the present study regarding clinical procedures are presented tentatively, and improvement and extension of the methodology are required. It appears, however, that acceptable results can be achieved by different programs and ultimately clinical choices may be based on factors such as complexity, costs, and demands of treatment. Standardization, centralization, and the participation of high volume operators were associated with good outcomes, and nonstandardization and the participation of low volume operators with poor outcomes. Therapeutic factors associated with good outcomes were the employment of a vomer flap to close the anterior palate, and poor outcomes with primary bone grafting and with active presurgical orthopedics.     

Presence and antibiotic resistance of Porphyromonas gingivalis,Prevotella intermedia,and Prevotella nigrescens in children

BACKGROUND/AIMS: Only limited information exists about the prevalence in children of pathogens associated with periodontitis. The aim of the present study was to determine by culture whether 8-11-year-old children carry Porphyromonas gingivalis, Prevotella intermedia, and/or P. nigrescens in samples from the gingiva and/or the buccal mucosa taken before, and after caries treatment and oral hygiene instruction. A second aim was to assess the proportion of subjects who had gram-negative anaerobes carrying the tet(Q) and erm(F) genes, suggesting antibiotic resistance to tetracycline or erythromycin. METHOD: A total of 150 children provided gingival and buccal swab bacterial samples that were cultured for P. gingivalis, P. intermedia, and P. nigrescens. The species was verified using DNA-DNA hybridization with species-specific probes made from the variable region of the 16S rRNA sequences. Antibiotic-resistant genes, tet(Q) and erm(F), were identified using specific DNA-DNA hybridization with specific DNA probes. RESULTS: A total of 116 isolates of black-pigmented bacteria were cultured from 47 (31%) of 150 children. Five isolates were identified as P. gingivalis, 29 as P. intermedia, 33 as P. nigrescens, and 49 as other species. In general, the bacteria were not culturable at more than one time period. We found that 55% of these 47 children harbored black pigmented bacteria that carried either one or both of the two antibiotic-resistant genes studied (tet(Q), and erm(F)). CONCLUSION: The present study demonstrated that children not exposed to regular dental treatment carry bacteria outside the gingival sulcus that have been associated with periodontitis, and that standard treatment procedures may not clear the presence of the putative pathogens. In addition, antibiotic-resistant genes are common in identifiable gram-negative anaerobes, including putative pathogens.