Testing for Differential Item Functioning Under the D-Scoring Method.

This study offers an approach to testing for differential item functioning (DIF) in a recently developed measurement framework, referred to as D-scoring method (DSM). Under the proposed approach, called P-Z method of testing for DIF, the item response functions of two groups (reference and focal) are compared by transforming their probabilities of correct item response, estimated under the DSM, into Z-scale normal deviates. Using the liner relationship between such Z-deviates, the testing for DIF is reduced to testing two basic statistical hypotheses about equal variances and equal means of the Z-deviates for the reference and focal groups. The results from a simulation study support the efficiency (low Type error and high power) of the proposed P-Z method. Furthermore, it is shown that the P-Z method is directly applicable in testing for differential test functioning. Recommendations for practical use and future research, including possible applications of the P-Z method in IRT context, are also provided.

Latent D-Scoring Modeling: Estimation of Item and Person Parameters.

This study presents a latent (item response theory-like) framework of a recently developed classical approach to test scoring, equating, and item analysis, referred to as D-scoring method. Specifically, (a) person and item parameters are estimated under an item response function model on the D-scale (from 0 to 1) using marginal maximum-likelihood estimation and (b) analytic expressions are provided for item information function, test information function, and standard error of estimation for D-scores obtained under the proposed latent treatment of the D-scoring method. The results from a simulation study reveal very good recovery of item and person parameters via the marginal maximum-likelihood estimation method. Discussion and recommendations for practice are provided.

Association between Bone Density Values, Primary Stability and Histomorphometric Analysis of Dental Implant Osteotomy Sites on the Upper Jaw.

INTRODUCTION: Sufficient bone volume, as well as the bone quality characteristics are necessary prerequisites to ensure optimal mechanical stability of the implants and subsequent osseointegration. AIM: The aim of the present study was to assess the correlation between bone density values obtained by cone-beam computed tomography (CBCT), the primary stability of dental implants and the histomorphometric analysis of bone quality. MATERIALS AND METHODS: Following tooth extraction, socket preservation with frieze-dried bone allograft or protein-rich fibrin (PRF) was performed on 30 patients with 30 maxillary teeth in the region from second premolar to second premolar. Four months after the procedure, CBCT was used to assess the bone density (Hounsfield units) in the area of extraction. Thirty bone samples were harvested from implant sites using a trephine drill. They were analyzed with Image J software. Immediately after placing the implant, the implant stability quotient was measured using the Osstell Idx device. RESULTS: The results revealed significant correlations between bone density and primary stability along the vestibulo-oral (r=0.392, p=0.032) and mesiodistal axes (r=0.407, p=0.026). Bone density also correlated strongly with the percentage of newly formed bone (r=0.776, p<0.001). CONCLUSION: Bone quality, in terms of bone density measured in CBCT and new bone formation are correlated to the primary stability of the dental implants and vice versa.

Correlation between CGRP Levels and the Neuropathic and Inflammatory Component of Postoperative Pain.

INTRODUCTION: In surgical procedures, tissue damage results in the release of a number of bioactive substances. Calcitonin gene-related peptide (CGRP) is a peptide released from sensory nerves, which determines its role in pain sensation. Its distribution in tissues deter-mines its role as a primary afferent neurotransmitter. AIM: To determine the effect of CGRP on postoperative pain and reactive inflammatory process after surgical removal of impacted mandibular third molars, as well as the factors that have influence upon the perception of pain. MATERIALS AND METHODS: Forty patients with bilaterally impacted mandibular third molars were included in the study. Venous blood samples were collected before and 24 hours after the surgical procedure in order to test their serum levels of CGRP and procalcitonin. Two weeks later the procedure was repeated. The difficulty of the surgical procedure, its duration and complications were assessed in all patients. RESULTS: The influence of some of the studied factors upon postoperative pain was established. Differences in the sensation of pain between the two sexes were found when comparing pain intensity reported by the patients. Significant difference between pain inten-sity after the 1st and 2nd surgical procedures (6 hours) was found in females (Z=2.63, p=0.009;), whereas in males the difference was observed at 24 hours (Z=1.99; p=0.047). Regarding the existence of sex-related association, а significant, strong positive correlation between CGRP levels after the 1st and 2nd surgical procedures (24 hours) was found in males (rxy=0.78; p=0.004), whereas in females this correlation was also significant, although moderately significant (rxy=0.44; p=0.020). CGRP levels at the first and second extractions were generally similar in males, and not as much in females. We proved significantly moderate positive association between CGRP and pulse levels measured before the second surgery (rxy=0.37, p=0.021). CONCLUSION: The results of our study suggest a significant role of CGRP in reactive (neurogenic) inflammation.

Aggressive Fibromatosis in the Mandible of a Child: A Rare Case Report.

Aggressive fibromatosis (AF) is an uncommon, benign, collagen-forming soft tissue neoplasm that is characterized by monoclonal myofibroblast cell proliferation and derived from musculoaponeurotic structures. It has a locally invasive pathological behavior and a high potential for recurrence. Fibromatoses with onset in infancy and childhood are characterized with higher cellularity and more aggressive growth. The mainstream management of AF is surgical removal with microscopically lesion-free margins. In advanced cases, radical surgery can lead to function loss and disfigurement. Hence, early diagnosis and management can avoid complications. Although uncommon (two to four cases per million per year are reported), approximately 25 percent of AF incidents occur in children younger than 15 years of age. Pediatric dentists are likely to be the first practitioners to encounter new cases of AF in younger populations and should have knowledge and understanding of this entity. The purpose of this report is to present a rare case of AF affecting the mandible of a young patient.

Discontinuation of Oral Antiplatelet Agents before Dental Extraction - Necessity or Myth?

BACKGROUND: The risk of excessive bleeding often prompts physicians to interrupt the antiplatelet agents as acetylsalicilyc acid and clopidogrel before dental extractions which puts patients at risk of adverse thrombotic events. AIM: To assess the bleeding risk during dental extractions in patients with continued antiplatelet therapy. MATERIALS AND METHODS: The study included 130 patients (64 men and 66 women) aged between 18 and 99 years old. Sixty-eight of the patients received 100 mg acetilsalicilic acid (ASA); these were divided into two groups: 34 patients continued taking ASA and 34 patients stopped it 72 hours before extraction. Sixty-two of the patients were treated with 75 mg clopidogrel; these were also divided into two groups: 31 continued taking clopidogrel and 31 patients stopped it 72 hours before extractions. Extraction was performed under local anaesthesia as no more than 3 teeth per visit were extracted. Local haemostasis with gelatine sponge and/or suturing was used to control bleeding. RESULTS: Mild bleeding was observed most frequently in the first 30 minutes, successfully managed by local haemostasis. Only 1 patient in the control and 1 in the experimental group receiving ASA reported mild bleeding in the first 24 hours, controlled by compression with gauze. No major haemorrhage requiring emergency or more than local haemostasis occurred. No statistically significant difference in bleeding between two groups was found. CONCLUSION: Single and multiple dental extractions in patients receiving acetylsalicylic acid or clopidogrel can be safely performed without discontinuation of the therapy with provided appropriate local haemostasis.

Aggressive juvenile mandibular fibromatosis.

Aggressive juvenile fibromatosis of the jawbones is a rare tumor presenting as infiltrative mass with unpredictable evolution. We report herein a 17-year-old student with a 6-month history of radiologically proven resorption of a part of the mandible, lingual displacement of tooth 34 and malocclusion. Alveolar ridge resorption and three dark-brown foci in the bone were seen after the tooth was extracted. Histological study showed the tumor tissue to have a bundle-like structure; immunohistochemically it was positive for vimentin, smooth muscle actin, beta-catenin, Ki-67 (5%), and negative for desmin and cytokeratin 34bE12. The golden standard in the diagnostics of desmoid fibromatoses is the nuclear or membrane expression of beta-catenin, which is found in 90% of the cases. Differential diagnosis include mandibular fibroma, well-differentiated fibrosarcoma, fibrosing histiocytoma, and infiltration from adjacent soft-tissue tumor. Aggressive juvenile fibromatosis should be managed by radical excision. Local recurrences are not rare, but metastases do not develop. In rare cases this type of fibromatosis has been known to regress spontaneously. Aggressive fibromatosis is a diagnostic challenge, since it remains in the grey zone between benign and malignant lesions of the oral cavity.

Dental anxiety in adults in Bulgaria.

UNLABELLED: The anxiety experienced by some patients before or during dental visits poses a problem for patients and the dental practitioners alike. Some people consider them a stressful experience which manifests itself as anxiety, fear and even phobia and results in avoidance of proper dental care. The dental anxiety, dental fear and dental phobia stand out against the background of general anxiety. The aim of the present study was to investigate dental anxiety in Bulgaria by means of a self-assessment scale. MATERIAL AND METHODS: The self-assessment Dental Anxiety Scale (DAS), developed by N Corah, was used in the form of a questionnaire containing questions about the gender, age, education and occupation of respondents. Subjects were 746 adults aged 18-82 years living in urban areas. Individual and group interviews were conducted directly with them. RESULTS: The respondents with moderate dental anxiety were the most of all subjects (35.5%, DAS score: 9-12 points), followed by the anxiety-free subjects (34.6%, 4-8 points). The third most numerous group was the high anxiety group (18.2%, 13-14 points), followed by the subjects with severe anxiety (11.7%, 15-20 points). The mean score was 10.26 +/- 0.14. We found a statistically significant correlation between anxiety, age (P < 0.05), education (P < 0.05) and type of labour (manual or mental labour) (P < 0.01). No significant difference was found between anxiety and sex (P > 0.05). CONCLUSIONS: The percentage of people scoring high on dental anxiety (DAS 13-20) in Bulgaria (29.9%) is considerably higher than that in some European and North American countries. The present study is the first in Bulgaria on dental anxiety. Further studies are needed to reveal other factors related to dental anxiety.

Ultrasound treatment of cellulitis in the maxillofacial region: a ten-year experience.

AIM: To evaluate the effect of therapeutic ultrasound in the treatment of cellulitis in the maxillofacial region. PATIENTS AND METHODS: We report our experience in the management of maxillofacial cellulitis in thirty six patients using therapeutic ultrasound as an adjunct to the standard treatment. The patients were allocated to two groups: group A, treated by surgery, drugs and ultrasound therapy, and group B, where the patients were treated only surgically and medicamentously. The effect of treatment was evaluated on the basis of inflamed tissue volume reduction and normalization of tissue structure determined by ultrasonography. RESULTS: The dynamic changes in the mean values of inflamed tissue volume indicated more rapid reduction in group A in which therapeutic ultrasound was applied. Analysis of the ultrasonographic images in group A demonstrated merging of the miliary liquid foci as early as the first day of treatment. They coalesced, and this coincided with the initiation of purulent discharge. The reduction in volume was due to the accelerated elimination of breakdown inflammatory products from the tissues. CONCLUSION: The better results in group A compared with group B suggest that the method for ultrasound management was effective and could be recommended for use in clinical practice.

Sarcomas of the mandible. Literature review and case reports.

Sarcomas of the maxillofacial region are rare tumors presenting with wide variety of histopathological and clinical features. The authors treated six patients with sarcomas of the mandible over a period of ten years: 2 patients with fibrosarcomas, 2 with lymphosarcomas, one with osteogenic sarcoma and one with chondrosarcoma. The patients' ages ranged from 28 to 65 years, one was male and five - female. The present study reports three cases (osteogenic sarcoma, fibrosarcoma, chondrosarcoma) with specific clinical and radiographic characteristics, demonstrating the differences between the various types of sarcomas. Special attention is paid to the first clinical signs and symptoms, and to the differential diagnosis with inflammatory conditions (post-extraction alveolitis, chronic odontogenic osteomyelitis), benign tumors (osteoblastoclastoma, ameloblastoma, odontogenic cysts, fibrous dysplasia) and centrally developing jaw carcinomas. Particular emphasis is given to CT imaging and morphological examinations in making an accurate diagnosis and providing adequate treatment. Early diagnosis and precise surgical treatment (total resection or hemiexarticulation, or neck dissection if submandibular or cervical metastases are present) are essential to achieve satisfactory management of these malignant neoplasms. The radiotherapy and chemotherapy administered according to the histologic features of the tumor are also of significance.

Vertical ramus osteotomy for treatment of mandibular prognathism.

Following a brief literature review of treatment modalities for mandibular prognathism the authors propose a simplified method for vertical ramus osteotomy. The method was successfully used in 24 patients with mandibular prognathism (alone or in combination with open bite). Postoperative complications (suppuration of the operative wound) were found in 2 patients (8%), and postoperative recurrences--in 5 patients (20.8%). No complications, usually associated with sagittal and vertical intraoral osteotomies (hypoesthesia of the trigeminal nerve, Frey's syndrome, dissecting aneurysm of the internal carotid artery) were found to be consequential to the proposed method.

A retrospective study of 3326 mandibular fractures in 2252 patients.

Fractures of the lower jaw are the most common facial traumatic injuries and their therapy dominates the treatment activities of oral and maxillofacial surgeons. The present study aimed at determining the types of mandibular fractures and the common trends in their treatment in patients who have sustained facial trauma. The patients have been treated for the last 15 years. MATERIAL AND METHODS. A retrospective study was conducted, which included a series of 3326 mandibular fractures in 2252 patients (1876 male and 376 female, aged 26 months to 85 years) treated in the Clinic of Dentistry between 1986 and 2000. The fracture distribution according to sex and age, anatomic localization, cause, time from trauma to treatment, methods of treatment and complications was investigated. The data were analysed statistically with descriptive statistics, non-parametric (Pearson's chi-square test) and graphic analysis. RESULTS. Mandibular fractures affect all ages; they occur five times as often in males as in females and predominate in young patients (20-29 years of age). The causes for fractures of the lower jaw are varied, the leading factor being assault and alcohol abuse (68.07 +/- 1.19%). According to anatomic localization, the fractures of the angle of the mandible prevail (34.15%), followed by fractures of the body (25.77%) and symphysis (19.57%). Mandibular fractures are treated using different methods, mainly closed reduction and fixation (78.16%) and less frequently open reduction and fixation (20.29%). Complications following treatment of mandibular fractures are encountered in 25.22% of the cases in the form of suppuration of facial wounds, post-traumatic haematomas, development of traumatic osteomyelitis or post-fixation contractures. CONCLUSION. The present study shows that mandibular fractures are not characteristic of certain sex or age, occur in all parts of the jaw and are treated by the methods of both closed and open reduction and fixation. Assault is the major cause of fractures of the mandible.

Sialolithiasis or complex odontoma?

We present a case of a 53-year old woman admitted for treatment in the clinic after detection of radiopacity in the left half of the mandible. The patient was operated on with a tentative diagnosis of complex odontoma. No pathological lesion was found intraoperatively after trepanation of the mandibular bone. Additional clinical examination and contrast media sialography of the left submandibular salivary gland in PA and lateral oblique view were instrumental in making the correct diagnosis and administering the proper treatment. This case demonstrates that difficulties may arise in differentiating between a sialolith and a complex odontoma.

Intermaxillary transalveolar fixation for treatment of mandibular fractures.

The author describes a technique for intermaxillary transalveolar fixation for management of mandibular fractures and discusses the results of treatment of 25 patients (19 male and 6 female) with 39 fractures (12 unilateral, 12 bilateral and 1 triple fracture). The technique was used as the only treatment (22 fractures in 14 patients) or in combination with intraosseous osteosynthesis by wires or miniplates (17 fractures in 11 patients). In comparison to traditional techniques the discussed method is simple and easy to implement, suitable for partially or totally edentulous patients. The indications for using this procedure as an alternative way of treating patients with inadequate dentition or edentulous jaws are presented.

Surgical treatment of chronic mandibular dislocation--report of a case.

Chronic dislocation of the temporomandibular jaw (TMJ) can result from lax joint ligaments and parafunctioning joints; it can also be a consequence of a systemic connective tissue disorder. The authors report a case of hypermobile joint syndrome in combination with mitral valve prolapse. The case was managed by osteosynthesis using modified titanium plate.