Effect of magnification on locating the MB2 canal in maxillary molars

The purpose of this study was to determine if the surgical operating microscope and/or dental loupes could enhance the practitioner's ability to locate the second mesiobuccal canal (MB2) canal of maxillary molars in an in vivo, clinical setting. The participating endodontists documented 312 cases of root canal therapy on maxillary first and second molars. Participants that used the microscope or dental loupes located the MB2 canal with a frequency of 57.4% and 55.3%, respectively. Those using no magnification located the MB2 canal with a frequency of 18.2%. When no magnification was used, significantly fewer MB2 canals were located based by Chi-square analysis at p < 0.01. There was no significant difference between the use of the microscope and dental loupes in the frequency of locating the MB2 canal. When the maxillary first molars were considered separately, the frequency of MB2 canal detection for the microscope, dental loupes, and no magnification groups was 71.1%, 62.5%, and 17.2%, respectively. The results of this study show that the use of magnification in combined groups leads to a MB2 detection rate approximately three times that of the nonmagnification group and that the use of no magnification results in the location of significantly fewer MB2 canals. Based on these results, more emphasis should be placed on the importance of using magnification for locating the MB2 canal.     

Techniques for immediate restoration of teeth following root canal therapy

It is incumbent upon the dentist to restore the form and function of endodontically treated teeth. Different approaches and materials are described in the literature for restoring the missing tooth structure, either with a cast post and core or immediately with a chair-side post and core system. This article briefly reviews the available data regarding the microbiological, prosthetic, mechanical, and periodontal aspects while emphasizing the immediate approach using amalgam, composite and glass ionomer materials. The factors affecting retention of the post are presented to guide the clinician in selecting a suitable post and core system in preserving optimal root structure to prevent root fracture. Two clinical cases are presented in which tooth structure was restored using two techniques: in one, a provisional acrylic resin shell was used to house a dowel coronal-radicular amalgam core material, the other used a copper band for a composite post and core system. Both cases emphasize the ease of production and the short chair-time in the stages of crown fabrication.     

A review of the clinical management of mobile teeth

The clinical management of mobile teeth can be a perplexing problem, especially if the underlying causes for that mobility have not been properly diagnosed. In some cases, mobile teeth are retained because patients decline multidisciplinary treatment that might otherwise include strategic extractions. This article discusses the relationship between occlusion and tooth mobility with an emphasis on identifying differences between increased mobility and increasing mobility. The indications, contraindications, and basic principles of tooth splinting are also reviewed. Provisional and definitive splints are defined and described with their respective occlusal considerations. Some mobile teeth can be treated through occlusal equilibration alone (primary occlusal trauma). Whereas mobile teeth with a compromised periodontium can be stabilized with the aid of provisional and/or definitive splinting (secondary occlusal trauma). It is important to consider splint therapy, because it may not only improve the prognosis of teeth, but may actually enhance the stability of the final prosthodontic treatment. The ultimate goal of successful management of mobile teeth is to restore function and comfort by establishing a stable occlusion that promotes tooth retention and the maintenance of periodontal health.     

Clinical comparison of bioactive glass bone replacement graft material and expanded polytetrafluoroethylene barrier membrane in treating human mandibular molar class II furcations

BACKGROUND: Class II furcations present difficult treatment problems and historically several treatment approaches to obtain furcation fill have been used. METHODS: The response of mandibular Class II facial furcations to treatment with either bioactive glass (PG) bone replacement graft material or expanded polytetrafluoroethylene (ePTFE) barrier membrane was evaluated in 27 pairs of mandibular molars in 27 patients with moderate to advanced periodontitis. Following initial preparation, full thickness flaps were raised in the area being treated, the bone and furcation defects debrided of granulomatous tissue, and the involved root surfaces mechanically prepared and chemically conditioned. By random allocation, PG or ePTFE was placed into or fitted over the furcations, packed or secured in place, and the host flap replaced or coronally positioned with sutures. Postsurgical deplaquing was performed every 10 days leading up to ePTFE removal at about 6 weeks. Continuing periodontal maintenance therapy was provided until surgical reentry at 6 months for documentation and any further necessary treatment. RESULTS: Direct clinical measurements demonstrated essentially similar clinical results with both treatments for bone and soft tissue changes. There were no statistically or clinically significant differences (e.g., mean horizontal furcation fill 1.4 mm PG, 1.3 mm ePTFE; mean percent horizontal furcation fill 31.6% PG, 31.1% ePTFE, both P>0.85). Seventeen of the PG treated and 18 of the ePTFE furcations became Class I clinically and 1 furcation completely closed clinically with each treatment. Intrapatient comparisons showed similar horizontal furcation responses with both treatments. CONCLUSION: The findings of this study suggest essentially equal clinical results with PG bone replacement graft material and e-PTFE barriers in mandibular molar Class II furcations. PG use was associated with simpler application and required no additional material removal procedures.     

Protease-active extracellular protein preparations from Porphyromonas gingivalis W83 induce N-cadherin proteolysis, loss of cell adhesion, and apoptosis in human epithelial cells

BACKGROUND: The protease-induced cytotoxicity of P. gingivalis may partly result from alteration of the extracellular matrix and/or surface receptors that mediate interaction between the host cells and their matrix. While P. gingivalis-induced degradation of E-cadherin has been documented, there is no information on the effects of P. gingivalis proteases on other members of this family of cell adhesion proteins. METHODS: Human epithelial KB cells were exposed to protease-active extracellular protein preparations from isogenic mutants of P. gingivalis. Quantification of apoptosis was performed by visualization of nuclei stained with 4,6'-diamidino-2-phenylindole. Alteration of cell adhesion proteins was examined by immunoblotting of cell lysates using monoclonal antibodies to those proteins. RESULTS: Treated cells exhibited loss of cell adhesion properties with apoptotic cell death subsequently observed. These effects correlated with the different levels of cysteine-dependent proteolytic activities of the isogenic mutants tested. Cleavage of N-cadherin was observed in immunoblots of lysates from detached cells. There was a direct correlation between the kinetics of N-cadherin cleavage and loss of cell adhesion properties. Loss of cell adhesion, as well as N-cadherin cleavage, could be inhibited by preincubation of P. gingivalis protease active extracellular protein preparations with the cysteine protease inhibitor TLCK. In control experiments, the cleavage of N-cadherin was detected after treatment of KB cells with trypsin but not after cell dissociation by a non-enzymatic method. CONCLUSIONS: These results suggest that extracellular proteases from P. gingivalis can induce degradation of N-cadherin, which could have implications for the pathogenicity of this bacterium.     

Metastatic transitional cell carcinoma of the urinary bladder presenting as a mandibular gingival swelling

Oral cavity metastases mostly originate from the breasts, lungs, or kidneys. Transitional cell carcinoma (TCC), the most frequent malignant tumor of the urinary bladder, rarely metastasizes to the jaws. To the best of our knowledge, only 8 cases of bladder carcinoma have been reported in the English literature to metastasize to the jawbones. A new case of mandibular metastasis of urinary bladder TCC with extension to the gingiva is presented in a 64-year-old white man. The patient was referred for a periodontal infection of the upper right first molar. The clinical examination also showed a gingival swelling located in the lower left premolar region with a hypoasthesia of the left side of the lower lip. The gingival mass was biopsied, and the microscopy showed a mandibular metastatic TCC of the urinary bladder extending to the gingiva. Periodontists should be aware that, although gingival metastases are rare, when they occur they may mimic other local benign pathological conditions.     

The global impression technic in fixed dentures

The global impression technique allows to obtain in a single stage the impression of the abutment as well as their neighboring teeth. This technique often requires the placement of one or two retraction cords in the sulcus. The impression technique herein described is the double mix method. This method is based on the use of two elastomers with different viscosities, but from the same group thus allowing a simultaneous polymerization.     

Use of a composite pedicled muscle flap and rhBMP-7 for mandibular reconstruction

The aim of this study was to investigate the feasibility of reconstructing critical size continuity osteoperiosteal defects of the mandible using a composite of recombinant BMP-7 contained in a bovine type-1 collagen carrier wrapped in a pedicled sterno-occipitalis muscle flap. At 3 months following surgery, bridging of the surgical defect was noted in three subjects (60%). Histologically, the induced bone regenerate showed maturation from woven to lamellar bone. Islands of cartilage were distributed throughout the defect. Replacement ossification of the degenerated muscle was a common feature in all specimens. Microradiography showed a gradual increase in the calcification of mineralized tissue from the margin to the centre of the newly generated bone. This research represents a proof of the concept that bone can be satisfactorily formed within a muscular scaffolding at the site of the created defect in a one-stage procedure.     

Epidemiology and aetiology of malocclusion among Syrian paediatric patients.

AIM: The knowledge of the distribution and causes of malocclusion in early childhood can prevent such malocclusions and their consequences and possibly to reduce complex orthodontic treatment. METHODS: All children (n = 234; 116 male, 118 female, age 2-16) who presented with occlusal or functional problems at the Department of Paediatric Dentistry at Damascus University (1995-1999) were classified according to the type and causes of malocclusion and the subsequent orthodontic treatment. RESULTS: 57.3% of the malocclusions affected the anterior-posterior plane, 12.4% the vertical, and 35.9% the transverse. Most of the malocclusions had causes which could be modified by preventive or interceptive efforts: thumb sucking (5.12%), infantile swallowing (3.84%), mouth breathing (0.85%), tongue thrusting (1.7%), delayed exfoliation of a primary tooth (3.41%), premature loss of a primary tooth (9.82%), delayed eruption of a permanent tooth (2.13%), or an impacted tooth (6.41%). The subsequent early orthodontic treatment consisted of space maintainers (26%), removable (40.9%), functional (11.9%), or fixed appliances (21.2%). CONCLUSION: These data stress the importance of early orthodontic diagnosis in paediatric practice. Malocclusion in this Syrian sample could be treated to a great extent with preventive or interceptive orthodontics, which required only simple appliances and techniques.