Assessment of cytogenetic damage in lymphocytes and in exfoliated nasal cells of dental laboratory technicians exposed to chromium, cobalt, and nickel

Dental laboratory technicians may be exposed to metal alloys that are used in the production of crowns, bridges and removable partial dentures. These alloys consist of 35-65% cobalt, 20-30% chromium, 0-30% nickel, and small amounts of molybdenum, silica, beryllium, boron and carbon. The aim of this study was to assess whether dental technicians are occupationally exposed to chromium, cobalt and nickel, by analyzing urinary excretion levels of these metals and to investigate the genotoxic effects of occupational exposure associated with dental prostheses production operations by analyzing cytokinesis-blocked micronucleus (CB-MN) frequencies in peripheral lymphocytes and micronucleus (MN) frequencies in exfoliated nasal cells from 27 dental laboratory technicians and 15 control subjects. The differences in the urinary excretion of metals between technicians and controls were statistically significant. The mean (+/-S.D.) CB-MN frequencies ( per thousand ) in peripheral lymphocytes were 4.00 (+/-2.98) among the dental technicians and 1.40 (+/-1.30) among the controls, a statistically significant difference (P<0.005). The mean (+/-S.D.) MN frequencies ( per thousand ) in nasal cells were 3.50 (+/-1.80) among the dental technicians and 1.19 (+/-0.53) among the controls, which was also a statistically significant difference (P<0.005). There was a significant correlation between duration of exposure and MN frequencies in lymphocytes (r=0.642, P<0.01), but not in nasal cells of technicians. Our data reveal that in vivo exposure to chromium, nickel and cobalt metals is evident and that this occupational exposure may contribute to the observed genotoxic damage in two types of cells, e.g. lymphocytes and exfoliated nasal cells. However, it cannot be determined which compound(s) are responsible for the genotoxic damage observed in this study.

Changes and equalization in hearing level induced by dental treatment and instruction in bilaterally equalized chewing: a clinical report

Hearing problems such as hearing loss and susurrus aurium are said to improve with occlusal treatment, but few objective clinical reports have been published in the dental field. We looked at the effect of occlusal treatment and chewing instruction on hearing ability in five patients who had an occlusal disorder and the unilateral chewing habit. The following results were obtained: 1. Unilateral chewing due to occlusal disorder may cause differences in hearing ability between the right and left sides (Cases 1, 2 and 3). 2. A reduction in the vertical dimension of occlusion is considered to be one of the factors that cause a decrease in hearing ability (Cases 4 and 5). 3. In all cases, occlusal treatment and chewing instruction lead to a improvement in hearing and to equalizing of hearing ability between low and high frequencies. These clinical findings indicate that there is a relationship between changes in hearing ability and oral function.

Dental materials and magnetic resonance imaging

The objective of this investigation was to evaluate the reaction of selected dental materials in the magnetic field of a magnetic resonance imaging device to determine a possible health risk. The following dental materials were tested in vitro during magnetic resonance imaging: 15 dental alloys, four dental implants, one surgical splint and two wires for fixation of maxillofacial fractures. Possible artefacts (corresponding with magnetic properties), heating and force effects were tested. Results concerning movement and heating were in agreement with the literature. The artefacts seen were significant: for the surgical splint, a spherical artefact with a diameter of 55 mm; for the wires, up to 22 mm; and for the dental blade implant, an artefact of 28 x 20 mm. The results of our tests of selected dental appliances indicate that their presence in the human organism is safe for patients undergoing magnetic resonance imaging procedures. The presence of artefacts can substantially influence the magnetic resonance imaging results.

[Eosinophilic ulcer of the oral mucosa: 11 cases]

BACKGROUND

The eosinophilic ulcer is a lesion of the oral mucosa, that has been infrequently described in the literature. This is a benign and self-limiting lesion of unknown origin.

CASE REPORTS

In this article, eleven new cases of eosinophilic ulcer of the oral mucosa are presented. The clinical, histologic and evolutive features are reviewed.

DISCUSSION

Recurrent trauma is clearly involved in the pathogenesis of this entity.

Periodontal considerations in restorative and implant therapy

The successful integration of periodontal and restorative dentistry for both natural teeth and implants requires knowledge and application of both mechanical and biological principles. In areas of aesthetic concern, an adequate band of attached gingiva can increase patient comfort, reduce the probability of gingival recession following tooth preparation and simplify restorative procedures. While some restorative margins need to be placed at or below the margin of the free gingiva, this should be considered to be a compromise, and margins should not be placed more than 0.5 mm into a healthy gingival sulcus. Approximately 2-3 mm of healthy, natural supra-alveolar tooth surface is needed for attachment of the gingival tissues to the tooth. This dimension is called the biological width. If adequate biological width does not exist, surgical or orthodontic procedures to expose healthy tooth structure are recommended before final restorations are placed. Retraction of soft tissues for impressions is best accomplished with mechanical methods rather than lasers or electrosurgery because of the potentially harmful effects of these devices to the cementum, bone and soft tissues surrounding the teeth. Implants function best and withstand occlusal forces optimally when loaded in a vertical direction. Therefore, planning implant placement is critical for success. Because of increased proprioception, it is suggested that natural teeth be used to guide the occlusion in partially edentulous patients. Cantilevers should be used with caution and with appropriate attention to occlusal forces. While occlusal trauma does not cause periodontal disease, it may contribute to bone loss around teeth and implants. In the opinion of the authors, provisional restorations are an integral part of dental and periodontal therapy. They can be used to establish aesthetic and physiological contours that can be easily cleaned by patients and they can also be used as a guide for any needed surgical tissue modification.

Prosthodontic biomaterials and adverse reactions: a critical review of the clinical and research literature

Prosthodontic biomaterials include impression materials, luting cements, and restorative materials. They consist of metals and alloys ceramics, and polymer materials and are retained in patients for <60 min or for decades. Oral release of compounds from biomaterials occurs, and adverse reactions may follow dental treatment. Especially in allergically vulnerable patients contact allergy may occur. There are reports from many different countries on contact allergy from gold/palladium alloys, components from polymer-based materials, chromium/cobalt alloys, and nickel. Notifications on adverse reactions in Norway, Sweden, and England are handled by a registry in which patient reactions and occupational exposure are recorded. Data from The Adverse Reaction Unit in Bergen and Umeå have been a most valuable basis in extending knowledge in a field of current interest in dentistry. A review of the clinical and research literature relating to prosthodontic biomaterials and adverse reactions shows that reliable methods seem necessary to expose the frequency of adverse reactions in general dentistry, including prosthodontic treatment.

Analysis of the risk of transmitting bovine spongiform encephalopathy through bone grafts derived from bovine bone

Bone substitutes of bovine origin are widely used for treatment of bone defects in dental and orthopedic surgery. Due to the occurrence of BSE and the new variant of Creutzfeldt Jakob Disease risks of transmitting diseases through the use of such materials need to be carefully evaluated. Risk analysis can either be based on theoretical assessments or experimental evidence. Here we present a comparative study on two bovine bone substitutes (Bio-Oss and Osteograf/N) which is based on theoretical values. Furthermore, for one of these materials, i.e. Bio-Oss, the prion inactivation capacity of one of the production steps was experimentally evaluated. Theoretical and experimental data indicate that the use of these materials does not carry a risk of transmitting BSE to patients.

Liver and kidney foreign bodies granulomatosis in a patient with malocclusion, bruxism, and worn dental prostheses

Granulomatous reactions caused by foreign bodies have been described in drug abusers, in subjects exposed to occupational pollutants, and more rarely, in association with the use of prosthetic devices. We describe a 62-year-old patient with multiorgan parenchymal granulomatosis caused by inorganic debris of unknown origin. The patient presented with fever, hepatosplenomegaly, progressive cholestasis, and acute renal failure. Liver and kidney biopsies showed the presence of noncaseating epithelioid giant-cell granulomas containing scattered polarizable particles. Similar particles were also present in stools. Studies by innovative scanning electron microscopy and energy-dispersive microanalytical techniques showed that the particles isolated in liver, kidney, and stools were made by feldspars, the main component of porcelain. No occupational or environmental exposure to these materials could be identified in this patient and the only reliable source of the porcelain debris turned out to be constituted by 2 dental bridges evidently worn because of a possible inappropriate construction, malocclusion, and bruxism. The porcelain of the dental prostheses had the same elemental spectrum of the particles isolated from stool specimens and liver-kidney granuloma. After identification of the dental prostheses as the most likely source of ceramic debris, and after their removal, the particles from stool specimens disappeared. The patient was then treated with steroids leading to a remission of the clinical symptoms and a decrease in granulomatous inflammatory reaction in both liver and kidney. This is the first report suggesting that a foreign body systemic granulomatosis can be associated with worn dental prostheses.

Quantity determination of T- and B-leucocytes in peripheral blood in patients with candida induced subprosthetic stomatitis

INTRODUCTION

The presence of pathological transformation of Candida species and especially of C. albicans is determined to a great degree by the status of humoral and especially of the cell-mediated immunity. The prosthetic stomatitis (Stomatitis subprothetica) and its development also depends on the immunological status of the organism.

PURPOSE

In the present study we have set as a purpose to define the quantity of B- and T-lymphocytes (T-early and T-late) in the peripheral blood in patients with subprosthetic stomatitis and isolated and proved C. albicans from the microbial prosthetic plate and the mucosa under the prosthesis.

MATERIALS AND METHODS

We defined the quantity of the early and late E-rosette-forming T-lymphocytes by the method of Bach (1973) and The B-lymphocytes with complement receptors by the method of Mendes et al (1974) in 69 patients with subprosthetic stomatitis and in 33 people with plate prostheses without stomatitis

RESULTS

In both of the studied groups an elevation of the early T-lymphocytes and lower values for the late E-rossette-forming T-lymphocytes compared to the normal values were found. The relative proportion of B-lymphocytes is insignificantly higher (p > 0.1) in the patients compared to the control group. The values of T- and B-lymphocytes vary in different directions and they must be interpreted individually.

Application of functional methods for prophylaxis of side effects after prosthetic treatment

The time of appearance and the clinical symptoms of the different periods of functional suitability (FS) and degradation of prosthetic constructions (PC) were studied. It was found that using appropriately chosen methods of functional diagnosis it was possible to foresee the moments when reversible changes in the prosthetic constructions began and when prophylaxis was possible in order to prolong the time of FS of PC, to delay the development of irreversible degenerative changes and to avoid side effects of prosthetics. Knowing the specific clinical manifestations and the time of appearance of different stages of FS it is possible to anticipate the changes that occur on the surface of the prosthesis and the soft tissues at specific moments of the period during which the prosthesis is in the mouth, and determine whether they will progress or not.

[Transesophageal gastrostomy]

For gastrostomy after thoracic esophagus extirpation its distal stump was used. It is confirmed, that transesophageal gastrostomy has a number of advantages. Pezzer's catheter can be used as gastrostomic tube which self-fixes in given position and secures reliable gastrostoma sealing. Suturing of the stomach to parietal peritoneum around gastrostoma is not more necessary. Deformation and reduction of the stomach size are excluded and stomach is kept ready for subsequent plastic replacement of the oesophagus. The operation gets oncologically more radical as a result of removal of paraesophageal cellular fat and potentially metastatic lymph nodes during mobilization of the oesophagus and cardia distal stump. The routine technique of transesophageal gastrostomy is described. This technique is applied in 17 patients. Complications were not registered.

Need for occlusal therapy and prosthodontic treatment in the management of temporomandibular disorders. Part II: Tooth loss and prosthodontic treatment

The second part of this review, evaluating the literature on the relationship between dental occlusion and temporomandibular disorders (TMDs), focuses on the aetiological importance of tooth loss and the place of prosthodontic replacement in the treatment of TMD. Loss of teeth and lack of posterior occlusal support seem to have little influence on the development of TMD, which calls into question the use of prosthodontic restoration as prevention or treatment for TMD. In addition, there are practically no studies assessing the benefit of instrumental analysis in diagnosis or comparing the outcome of prosthodontic treatment with simple reversible methods in the management of TMD. There is a trend in the current literature to abandon any treatment, including positioning appliances and prosthodontic measures, to 'recapture the disk' in patients with disk displacements because of the favourable, long-term results achieved after using more simple methods. It is concluded that prosthetic therapy in TMD patients is not appropriate for initial TMD treatment and should only be carried out on prosthodontic indications after reversible treatment has alleviated pain and dysfunction.

The role of dentistry in palliative care of the head and neck cancer patient

Although palliative care for the terminally ill is based on a multidimensional philosophy to provide whole-person comfort care while maintaining optimal function, it does not usually include dentistry in its team approach. Dentists can have a significant role in the care of these patients by providing total, active comfort care of the oral cavity. The function of the oral cavity is essential to the patient's ability to thrive. Therefore, alleviation of pain and prevention of infection in the oral cavity should be a priority in providing total, active comfort for the patient. The oral problems experienced by the hospice head and neck patient clearly affect the quality of his or her remaining life. Through routine assessments and interventions by a dentist on the palliative care team (Figure 4), comfort care for the patient may be improved by the maintenance of oral hygiene and procedures to hydrate the oral mucosa. In addition, routine dental assessments may identify dental disease and facilitate dental interventions for caries, periodontal disease, oral mucosal problems or prosthetic needs. Attention to such detail may reduce not only the microbial load of the mouth but the risk for pain and oral infection as well. This multidisciplinary approach to palliative care, including a dentist, may reduce the oral debilities that influence the patient's ability to speak, eat or swallow. Not only does maintenance of oral health have impact on the quality of life, which is already challenged by the disease, but it also aids in the ability of patients to thrive for whatever precious time is left to them.

New developments in jewellery and dental materials

This communication reviews the latest alloys introduced in the fields of jewellery and dental prostheses. For this we have scanned current patents and others to which we have access, and it is evident that, although not always correctly used, the words "antiallergic", "hypoallergic", "non-allergic", "to avoid allergies", etc., now appear frequently, indicating manufacturers' awareness of the problems that nickel can cause. On the other hand, the problems that may be associated with other sensitizing metals, such as cobalt and palladium, are not yet addressed.

The role of dental prostheses in alveolar ridge squamous carcinomas

BACKGROUND

Alveolar ridge squamous carcinomas develop in patients outside the usual constellation of risk factors.

OBJECTIVE

To determine whether the use of dentures was a risk factor specific to patients with alveolar ridge carcinoma.

DESIGN

Case-control method with a unique control group-a concurrent cohort of patients with head and neck cancer with primaries in the oropharynx, hypopharynx, and larynx.

SETTING

Tertiary care hospital-based clinic.

PATIENTS

Forty-one patients with squamous carcinomas centered on the maxillary or mandibular alveolar ridges. The control group was 175 concurrently seen patients with squamous carcinomas of the laryngopharynx for whom dental status was known.

MAIN OUTCOME MEASURES

Age at diagnosis, sex, tobacco use, alcohol use, and denture use.

RESULTS

Patients with alveolar ridge were more likely to be female, older, nonsmokers, and nondrinkers. The crude odds ratio of denture use in patients with alveolar ridge cancer was 2.28 (P=.03). Eliminating other confounding factors with logistic regression, the adjusted odds ratio dropped to 1.30 (P=.59). Among patients with alveolar ridge, smoking status correlated with age and gender: current smokers were on average 64.4 years old and 9 of 16 were men. Nonsmokers' average age was 79.1 years and 1 of 11 was a man.

CONCLUSIONS

In this study, denture use was not an independent risk factor for alveolar ridge carcinomas. Among patients with little to no tobacco or alcohol exposure, the alveolar ridge carcinomas tended to occur in the elderly and in women.