Microbial leakage evaluation of the continuous wave of condensation

Coronal leakage has been recognized as a cause of pulpal and periradicular disease. Although cleaning and shaping of the root canal system is considered paramount, obturation of the system is an important step in endodontic success. The purpose of this study was to evaluate coronal bacterial leakage in teeth obturated with the System B continuous wave of condensation technique, followed by an Obtura II backfill, versus teeth obturated using the lateral condensation technique. Sixty single-rooted bilaterally matched teeth were evaluated in this study. An anaerobic bacterial leakage model was used. Results indicate that microbial coronal leakage occurs more quickly using lateral condensation than with the System B continuous wave of condensation and Obtura II backfill. This difference was statistically significant (p < or = 0.05). However, there was no statistical difference between groups 1 and 2 in the numbers of teeth that demonstrated bacterial leakage at the end of the study.     

Factors influencing defects of rotary nickel-titanium endodontic instruments after clinical use

This study examined used, discarded rotary nickel-titanium instruments obtained from 14 endodontists in four countries, and identified factors that may influence defects produced during clinical use. A total of 7,159 instruments were examined for the presence of defects. Unwinding occurred in 12% of instruments and fractures in 5% (1.5% torsional, 3.5% flexural). The defect rates varied significantly among endodontists. Instrument design factors also influenced defect rate, but to a lesser extent. The mean number of uses of instruments with and without defects was 3.3 +/- 1.8 (range: 1-10), and 4.5 +/- 2.0 (range: 1-16), respectively. The most important influence on defect rates was the operator, which may be related to clinical skill or a conscious decision to use instruments a specified number of times or until defects were evident.     

Paracetamol versus paracetamol-codeine in the treatment of post-operative dental pain: a randomized,double-blind,prospective trial

BACKGROUND: Codeine is frequently added to paracetamol to treat post-operative dento-alveolar pain; studies have shown effectiveness in relief of post-operative pain at high doses but at the expense of central nervous and gastrointestinal side effects. There has been no trial to compare the efficacy and safety of paracetamol 1000 mg with paracetamol 1000 mg combined with codeine 30 mg. METHOD: A randomized, single centre, double-blind prospective parallel group trial was performed to compare paracetamol 1000 mg with paracetamol 1000 mg with codeine 30 mg for the relief of pain following surgical removal of impacted third molars, and analysed on an intention-to-treat (ITT) basis. Eighty-two patients were assigned randomly to receive either drug for a maximum of three doses. Patients recorded their pain intensity one hour after surgery and hourly thereafter for 12 hours. RESULTS: The average increase in pain intensity over 12 hours was significantly less in patients receiving paracetamol plus codeine than in those receiving paracetamol alone (p=0.03) -1.81 cm/h compared with 0.45 cm/h - a difference of 1.13 cm/h (95 per cent CI: 0.18 to 2.08). Of the patients who received the paracetamol codeine combination, 62 per cent used escape medication compared with 75 per cent of those on paracetamol alone (p=0.20). There was no significant difference between the two groups in the proportion of patients experiencing adverse events (p=0.5). CONCLUSION: A combination of 1000 mg paracetamol and 30 mg codeine was significantly more effective in controlling pain for 12 hours following third molar removal, with no significant difference of side effects during the 12 hour period studied.     

Bone strain patterns of the zygomatic complex in response to simulated orthopedic forces

Craniofacial bone strain upon orthopedic loading has rarely been characterized, despite its fundamental importance in our understanding of the anabolic and catabolic effects of orthopedic forces. The present study tested the hypothesis that zygomatic bone strain is modulated upon loading by headgear, a device widely used in craniofacial orthopedics. Ramp forces from 0 to 50 Newtons were applied via headgear attached to the permanent maxillary first molars in four juvenile and five adult human skulls. The average peak bone strain of the juvenile temporal articular eminence was significantly higher than the adult articular eminence (p < 0.05). Contrasting bone strain patterns were identified in the zygomatic arch: tensile in its lateral surface but compressive in its medial surface. The peak bone strain of the temporal articular eminence and the zygomatic arch both depend upon loading direction. Thus, headgear-generated orthopedic forces evoke bending of the zygomatic arch and stresses of the temporal articular eminence in vitro, suggesting the need to verify whether bone strain induces in vivo bone modeling and remodeling.     

Mandibular distraction osteogenesis reconstructed the upper airway in a case of Melnick�CNeedles syndrome

Introduction

We report a 16-year-old female with Melnick?CNeedles syndrome complicated with severe obstructive sleep apnea?Chypoxia syndrome.

Clinical report

An overnight sleep study demonstrated that the patient had severe obstructive sleep apnea with an apnea?Chypopnea index of 95/h. The lowest oxygen saturation was only 34%. The distraction osteogenesis technique was used to lengthen her mandible for the reconstruction of her upper airway.

Result and Discussion

Postoperative panorex showed that the bilateral body of her mandible had been distracted about 16?mm singulorumly in the end of our distraction. Lateral radiograph revealed that the diameter of oral pharynx widen nearly 5?mm. The patient recovered after the upper airway reconstruction.     

Capacity for training in clinical research: status and opportunities

The ability to base patient care on scientific evidence depends in part on the results of translational and applied research. The shortage of trained clinical researchers identified by several sources limits the availability of clinical research studies upon which to base evidence-based therapeutics. This premise suggests that the dental profession needs to train more clinical researchers and faculty to conduct clinical research and to teach its applications to practice. Increasing opportunities for clinical research training in a variety of settings should eventually increase the numbers of clinical researchers, raise faculty involvement in clinical research, and promote science transfer. This paper reports on the current status of clinical research in dental schools, specifies the diverse groups involved in the clinical research enterprise, and identifies underutilized opportunities and partnerships for clinical research training. Data on federal and nonfederal funding of clinical research and training programs are presented. Existing and novel mechanisms for expanding clinical research training throughout and across traditional as well as unconventional environments are explored.     

Cross-sectional assessment of caries and periodontitis risk within the same subject

Dental caries and chronic periodontitis may be synergistically associated, negatively associated, or completely independent. The present report examines this relationship by comparing the susceptibility to chronic periodontitis and caries within the same individual. From an 800-patient sample, a periodontitis risk score was derived by radiographic assessment of bone loss in quarters of optimum bone height and obtaining for each subject a mean score based on all measurable surfaces. Similarly the caries risk was determined radiographically from the total decayed and filled teeth (DFT), as a percentage of the total teeth measured. The Mantel-Haenszel technique was used for analysis of the relationship between periodontitis and caries and data was stratified on four categories of age, sex, and numbers of teeth present. This analysis revealed no systematic patterns, indicating that the risks of caries and periodontal diseases are unrelated (chi 2 = 0.00; 1 df; P greater than 0.50). In addition, a regression analysis, which was controlled for sex and age, indicated a marked lack of association between caries and periodontitis (P = 0.94). Thus, although these common diseases share putative etiologic factors such as oral hygiene practices and dental attendance pattern, the major risk factors are probably quite different.     

Training pathways for careers in dental, oral, and craniofacial research

There are virtually unlimited opportunities for biomedical research training through either extramural or intramural training mechanisms, with programs designed for both the pre- and postdoctoral educational levels. The only difficulty is selecting from the vast array of research topic areas.     

Studies of herpes simplex virus and interferon in human gingival cell cultures.

Cultures of human gingival fibroblast cells from patients with a positive or negative history of recurrent herpes simplex virus (HSV) infection were compared with respect to susceptibility to HSV infection and interferon activity. There was a possible inverse relationship between interferon sensitivity of gingival fibroblast cells and a clinical history of recurrent disease. No correlation was found between prior infection and other parameters of interferon activity or susceptibility of the cells to HSV.