Document QkpE05eEoJeevM1RYKv4w57B6

FILE NAME Dental Asbestos DEN DATE 2017 Feb DOC DEN006 DOCUMENT DESCRIPTION Journal Article - Case Report - Pleural Malignant Mesothelioma in Dental Laboratory Technicians A Case Series Accepted 28 February 2017 DOI 10 1002 22716 CASE REPORT Pleural malignant mesothelioma in dental laboratory technicians A case series Carolina Mensi BSc PhD,, Francesco Ciullo MD | Gino Pietro Barbieri MD | Luciano Riboldi MD,, | Anna Somigliana Phys4 | Giulio Rasperini DDS5 | Angela Cecilia Pesatori MD PhD | Dario Consonni MD PhD,, 1 Department of Preventive Medicine Fondazione IRCCS Ca Ospedale Maggiore Policlinico Milan Italy 2 Department of Clinical Sciences and Community Health Universit^ degli Studi di Milano Milan Italy 3 Formerly Mesothelioma Registry Occupational Health Unit Local Health Authority Brescia Italy 4 Center of Electron Microscopy Lombardy Environmental Protection Agency ARPA Milan Italy 5 Department of Biomedical Surgical and Dental Sciences Universita degli Studi di Milano Milan Italy Correspondence Carolina Mensi BSc PhD Clinica del Lavoro Luigi Devoto Fondazione IRCCS Ca Granda- GrandaOspedale Maggiore Policlinico Via San Barnaba 8-20122 Milano Italy Email carolina.mensi@unimi it Asbestos was used in dentistry as a binder in periodontal dressings and as lining material for casting rings and crucible However until now only one case of malignant mesothelioma with occupational exposure to asbestos in dental practice has been reported We present 4 pleural mesotheliomas out of 5344 cases identified in Lombardy Italy in 2000-2014 Three men had been working as dental laboratory technicians with asbestos exposure for 10 34 and 4 years and one woman had been helping her husband for 30 years in manufacturing dental prostheses The men described the use of asbestos as a lining material for casting rings while the woman was not able to confirm this use We confirm the association of malignant mesothelioma with dental technician work Dental technicians suffering from mesothelioma should be questioned about past occupational asbestos exposure KEYWORDS asbestos dental technician dentistry mesothelioma occupational exposure 1 INTRODUCTION Exposure to asbestos fibers is a risk factor in the development of malignant mesothelioma MM a cancer arising from the serous membranes of the pleura and less frequently of the peritoneal and pericardial cavities and from the tunica vaginalis testis Prognosis is severe and median survival for the pleural form is around 9 months since diagnosis in population studies.,,Many western countries are currently suffering a MM epidemic considering the extensive use of asbestos between the 1950s and the 1980s in several applications and the long latency period around 40 years on average since the beginning of exposure Due to the past use of asbestos lining material for casting rings since approximately 1930 or as a binder in periodontal dressing since 1967 dental technicians and dentists were potentially exposed to asbestos.2 To our knowledge only a few cases of pneumoconio- sis small opacities or pleural plaques have been reported,,and only one case of pleural MM with documented occupational exposure to asbestos has been reported in the literature The aim of the manuscript is to describe cases of pleural MM in dental laboratory technicians identified by the Lombardy Mesothelioma Registry RML North Italy in 2000-2014 2 | METHODS 2.1 | The lombardy mesothelioma registry Since the asbestos ban in 1992 Italy has been one of the most active countries in prevention and control of asbestos diseases A dedicated system of epidemiological surveillance was implemented through the National Mesothelioma Register ReNaM active since 1993 by force of law since 2002 with the remit of estimating MM incidence investigating occurrences of asbestos exposure identifying Am J Ind Med 443-448 wileyonlinelibrary journal '2017 Wiley Periodicals Inc | 443 4W 44 ILEWY ILEY any possible underrated or unknown source of asbestos contamination and promoting research Being part of the ReNaM structure of Regional Operating Centers CORs the RML established in 2000 collects all MM cases diagnosed in people living in Lombardy one of the most populated and industrialized regions in Italy currently almost 10 16,17 million inhabitants even if admitted to hospitals outside Lombardy The information concerning occupational and occupational history is collected through administration of a standardized questionnaire by trained interviewers to the patient or to her next Detailed information on lifetime occupational history Industry occupation work environment characteristics and lifestyle habits are collected including information on cohabitants father mother spouse other with whom the patients have been living especially whether the cohabitant used to bring dirty working clothes at home to be brushed or washed Moreover information about domestic and leisure activities involving exposure through containing objects and environmental exposures during lifetime residential history presence of asbestos cement tiles or watertanks of industrial plants nearby ie asbestos cement chemical railroad or shipbuilding industries is elicited A panel of experts classifies lifetime asbestos exposure as occupational familial ie related to the cohabitant leisure ie related to activities regarding the house or environmental.18 For the purpose of this paper we extracted from MM cases diagnosed in the period 2000-2014 records of patients who had been working in a dental laboratory and described their clinical and occupational history 3 | RESULTS Four patients were found out of 5344 incident MM cases All pleural MM were histologically diagnosed Table 1 3.1 | Patient 1 The first patient was a year man evaluated for dyspnea in May 2004. Chest ray revealed a right pleural effusion with pulmonary atelectasis due to a mass obstructing the lower lobe bronchus After thoracentesis he underwent videothoracoscopy multiple lung pleural and diaphragmatic nodules of neoplastic appearance were present Histological and immunohistochemical analysis provided the diagnosis of epithelial MM Extensive surgical treatment was performed by pleuropneumonectomy excision of the pericardium and of the right hemidiaphragm infiltration removing the peritoneal apex too Pericardial and right hemidiaphragm reconstruction was performed The patient underwent chemoradiotherapy He died 8.0 months after diagnosis 3.1.1 | Occupational exposure From 1953 to 1963 from 21 to 31 years old he worked as a dental technician His activity consisted in preheating one or two cylinders in a dedicated oven for the subsequent metal wax model casting placing a positive tooth reproduction of wax in the cylinder and then in MENSI ET AL another small oven heated by means of a platinum electric resistance Until 1957 the worker used cylinders with inner lining in refractory material and insulated with asbestos he made five or six castings every week For 6-8 years he had also been using asbestos gloves never replaced when putting the cylinders inside the preheating oven and then into the casting oven The subject never used to do maintenance and cleaning of the furnace He used compressed air to clean products From 1964 to 1988 he worked as freelance dental technician using closed casting machines 3.1.2 | occupational exposure No other sources of asbestos exposure were identified 3.1.3 | Analysis of asbestos bodies and fibers Lung samples from one lobe were available to be analyzed Asbestos body and asbestos fiber burden were measured number per grams of dry weight of lung tissue gdw Lung tissue was digested with hypochlorite and analyzed with optical microscopy at 500 magnification asbestos fibers length 1 mwere counted by means of a Scanning Electron Microscope equipped with ray fluorescence microanalyses at 12 000 amplification The asbestos body burden was 22 gdw 95 confidence interval CI 16,000-30,000 detection limit gdw The asbestos fiber burden was below the detection limit of 380,000 3.2 | Patient 2 The second patient was a year woman The onset of the symptoms was in June 2004 with left chest pain and pneumothorax After chest drainage a scan showed effusion and thickening of the middle right pleura The patient underwent partial left pleural excision aimed at histological sampling Histological examination of the left parietal and visceral pleura and of lower lobe lung parenchyma showed a biphasic malignant mesothelioma The patient underwent a second operation with histological samples showing infiltrative epithelial MM and then chemotherapy She survived 4.3 years 3.2.1 | Occupational exposure From 1959 to 1961 from 16 to 18 years old she worked as a clerk in lawyer's office From 1961 to 1991 she worked as a housewife but she used to help her husband in the production of prostheses in his dental laboratory From 2001 to 2004 she worked as a clerk 3.2.2 | occupational exposure The patient reported that at the end of the 1980s she helped her husband in building a sound barrier at the boiler room in order to insulate a power unit she held an asbestos slab while her husband drilled holes in it She had been living from 1946 to 1964 with her father dental technician working in his own laboratory 3.3 | Patient 3 A year man in 2013 was evaluated for transitional papillary carcinoma of the bladder first diagnosed in 2008 After being MENS} eT AL Alp O} ewoujes JeyUSp UMO ELOT 9P6T B ul 8/Q0'Z SIY Suni ansiy Woy Ul Jayes Aueyide pasdejai ul patients BuIA JOY SUDJOM patients JO Usaq YM srapejq Morphlogy anlyse anlyse Ocupationl diagnosis Morpholgy Diagnosis Diagnosi Certain Ocupational Ocupational Ocupational x! t WILEY LEN} STR IRINA 445 SyJUOW sieak JRAINS, Q 8 op 204 aunsodxe sued ON ON TIYJO S$ 3)9A-pasoyd UEIDYA} Je}UEP sdAME|] E Aroysiy {2IUSP Epitheloid BuISN saulyoew Ul Certain poeuynds9O Epitheloid Epitheliod UeIYyId) Certain Certain + 2014 -WAD ulUnayed +1890; PUIZSeD -W4D < saApeu Epitheloid Epitheliod Certain +7-3W8HCalretin siouseiq uleyaD uleya> embryonic sjuaijed =Adqjoyiw=y s ployauzdy SIoUSeIp uno} jo ayy seaA vo c yo ? jo = AB Putas) W A soiuayveD aay (s4A} cL 9 Latvi quaned T 1964-8 No casting $T EP4- ON aiqsog 49y jO prosthes Buidjay UNpOoRsd jequap sity calretin sayy UE ur 201-04 201-04 EP4- calretin calretin , 1952-6 1952-56 years UONdISUes] ON ON alqisod ayued Possible uonesyiwupeproduction jejUap Posible URIDULID PIOJAU) Jtechonian DtUechnyiNcan Neo No SDIUL|IA | montLhs-L technian technican technian Posible Posible UE} -6S96T 4OWN] SLUPIA 195-9 clerk T-LA administration adminstration atend Posible years 1960-64 years atended 1965-9 Definte pdg-s8g uasijUe Ployerdg ployady <TOZ yTO? MUOAIqWa-DE WID a W 6 OL UNeayoA2 ued D-Ued | 4D 46 OF -Wiley- -Wiley- -Wiley- evaluated by positron emission tomography for recurrent right pleural effusion the patient underwent videothoracoscopy Diffuse whitish pleural thickening was observed and the lower right lung lobe visceral pleura the diaphragmatic pleura and the anterior and posterior mediastinal pleura were reported as flaking layers of fibrinous and cerebriform tissue Histological and immunohistochemical analysis provided the diagnosis of epithelioid MM Nine months later a scan reported vast pleural thickening and peritoneal carcinosis He survived 11 3 months 3.3.1 | Occupational exposure From 1952 to 1956 from 18 to 22 years old he worked as a dental technician His activity consisted in the production of crowns dental bridges and prostheses in a dental laboratory An electric oven for the metal wax model casting was present From 1957 to 1959 he was inspector of radio valves and from 1959 to 1999 employee in the public administration 3.3.2 | occupational exposure No definite asbestos exposures he did some domestic electrical work were reported 3.4 | Patient4 A year man was diagnosed in 2013 with hilar fibrosis in a hospital admission for traumatic subarachnoid hemorrhage and underwent resection of prostatic carcinoma follow being regular In the following year he was evaluated for acute respiratory distress a scan showed effusion of the right hemithorax without contrast enhancement of the pleura As the pleural liquid cytology revealed hyperplastic atypical mesothelial cells suspect of mesothelioma in 2014 he underwent videothoracoscopy Ubiquitous pleural thickening with multiple subtle nodules were sampled for histological and immunohistochemical analysis which revealed an epithelioid MM He died after 1.5 years 3.4.1 | Occupational exposure From 1960 to 1964 from 16 to 20 years old he attended a dental technician laboratory school in Milan He was a freelance dental technician from 1965 to 1999 and stated that asbestos was cut from large rolls kept in the laboratories and used for lining rings in wax model casting prosthesis formation He had been repeating the process twice a week for 10 years 3.4.2 | occupational exposure No other asbestos exposures were reported 4 | DISCUSSION We described four cases of pleural malignant mesothelioma associ- ated with dental technician work who came to the attention of the RML They had all been exposed or possibly exposed to asbestos while MENSI ET AL working as or helping dental laboratory technicians For each subject the diagnosis was confirmed by histology and immunohistochemistry The first case described asbestos exposure during production of prostheses based on wax model casting Until 1957 he used casting rings lined with asbestos and also stated that asbestos gloves were used for 6-8 years to insert the cylinders into the oven and that compressed air was used air to clean products The fourth case reported cutting asbestos from rolls kept in the laboratories for lining rings in wax model casting Choudat and Radi et 12 described the process of prosthesis formation based on wax model casting a positive reproduction of the tooth is made in wax this pattern is placed in a cylinder which is filled with refractory material The wax is eliminated by heating leaving an empty mould chamber Molten alloy is injected into the mould which is then broken and the prosthesis is polished with a sandblaster and hand finishing tools It is known from ReNaM Guidelines that asbestos had been used albeit in small quantities by Italian dental technicians in the lost wax model casting.18 In the second case we could only document indirect exposure to asbestos while helping her husband for 30 years in dental prosthesis manufacturing It is well documented that asbestos has been used in dentistry since approximately 1930 when it was introduced a as lining material 2 for casting rings Paper and powder containing asbestos fibers were used respectively in the production of metal prostheses and as a 14 binder in periodontal dressing until the middle of 70's The above mentioned procedures for prosthesis formation were the main production method and therefore they could apply also to the third patient even if he reported a less detailed history Since 1976 the Council on Dental Therapeutics reported a hazard of exposure to airborne fibers from asbestos used as binder and to line casting rings or crucibles for casting machines the fibers being readily released into the air from periodontal dressing powders and from large rolls of asbestos kept in the laboratories A simulation of fibers dispersion in the USA showed low concentrations 0.005-0.092 fibers 0.001-0.006 fibers 20 weighted average TWA of chrysotile fibers Another simulation study in Greece found a concentration of 0.008 fibers chrysotile only during a 4 sampling period in a dental laboratory where pleural plaques had been found in three dentists who used to manipulate wet asbestos tape during casting operations A recent study found asbestos unspecified type concentrations of 0.0104-0.0159 fibers 21 mL in dental laboratories in South Korea To our knowledge there are no data on asbestos concentrations in dental laboratories in Italy The hazard from airborne asbestos during various periodontal surgical procedures has been highlighted since 1976. oxide periodontal dressings consisted of a mixture of a liquid and a powder containing asbestos fibers as a binding agent Asbestos fibers were indeed used in gingivectomy packs.Use of a resin containing asbestos between 1967 8 and 1968 at the Royal Dental Hospital London was reported Despite the documented use of asbestos in dentistry only one case of MM arising in workers exposed to asbestos fibers during dental practice had been documented Another case of MM in dentist was reported in an obituary but asbestos exposure was not investigated The British dentist's exposure reported by Reid et 14 may have been occupational as only blue asbestos fibers amphibole MENSI ET AL expensive asbestos type not commonly used in dental application were found in lung tissue In the United States only white asbestos chrysotile has been used in dentistry.20 Raw materials were similar in the US and UK Although biopersistence of amphibole fibers is greater than that of chrysotile fibers clearance of long chrysotile fibers is slow or insignificant therefore a clearance effect does not seem to be an adequate explanation Also the source of exposure in the case described by Reid et al.14 remains unclear because that subject may have inhaled blue asbestos used in British gas masks during World War II.20 Pleural plaques and pneumoconiosis secondary to manipulating 10,13,24 asbestos tapes during casting operations have been reported Dental laboratory technicians often start to work early at the age of about 18 years are often employed and work alone or in small laboratories Moreover these workplaces have usually inadequate methods of dust control and employed subjects often work more than h per day with no information about occupational risks 1924 Since asbestos was banned in 1992 the possibility that asbestos containing materials are today present in dental laboratories in Italy is remote Asbestos exposure is currently a possibility in countries where asbestos is still used or was banned only recently Asbestos bodies and asbestos fibers in lung tissue have been used for many years as useful markers of cumulative dose and in documenting past exposure to amphiboles These markers are less useful in the case of chrysotile exposure because of the low biopersistence of this type of asbestos In the first patient the asbestos body burden 22,000 was significantly higher than the limit of 1,000 recommended by the Helsinki Consensus Document indicating past asbestos exposure with high probabil- ity Conversely fiber concentration was below the laboratory detection limit This result could be explained by the fact that the patient had probably been using chrysotile and that lung fiber analysis was performed 47 years after last asbestos exposure On the other hand asbestos bodies are largely produced by long amphibole fibers while production from chrysotile is negligible Hence we can hypothesize that chrysotile materials used by the patient were contaminated by amphibole asbestos None of the patients described in this paper was aware of the asbestos type used Finally it should be recognized that for patient 1 only one lung lobe was available for asbestos body and asbestos fiber burden Hence analysis performance was probably suboptimal To improve sensitivity the recommended procedure is to pool lung samples from all lobes of both lungs In conclusion we have documented two MM cases related to dental technician work with definite asbestos exposure and two with possible occupational asbestos exposure For all of them we filed claims for compensation to the Italian Workers Compensation Authority INAIL Only the first patient was compensated because the other subjects being employed or not formally employed the woman were not covered by work insurance Availability of a registry focused on MM has provided a fundamental aid in discovering unrecognized or overlooked due to the long latency of the disease sources of asbestos exposure Dental technicians suffering from mesothelioma should be questioned about past occupational asbestos exposure WILEY ACKNOWLEDGMENT The authors wish to thank Pier Alberto Bertazz~- for his helpful comments on an earlier draft of the manuscript AUTHORS CONTRIBUTION Mensi Carolina conceived the study collected and evaluated clinical and interview data and drafted the manuscript Ciullo Francesco evaluated clinical and interview data and drafted the manuscript Barbieri Pietro Gino collected and evaluated clinical and interview data contributed to interpretation of findings and discussion and collaborated to draft the manuscript Riboldi Luciano evaluated clinical and interview data and contributed to interpretation of findings and discussion Somigliana Anna performed the laboratory tests fiber and asbestos body count and contributed to interpretation of findings and discussion Rasperini Giulio contributed to interpretation of findings and discussion Pesatori Angela Cec^>lia contributed to interpretation of findings and discussion Consonni Dario collaborated to draft the manuscript and contributed to interpretation of findings and discussion All authors revised and approved the manuscript for intellectual content FUNDING None ETHICS APPROVAL AND INFORMED CONSENT As reporting of malignant mesothelioma to the Registry is compulsory by law ethics approval is not required DISCLOSURE AUTHORS The authors report no conflicts of interest DISCLOSURE BY AJIM EDITOR OF RECORD Rodney Ehrlich declares that he has no conflict of interest in the review and publication decision regarding this article DISCLAIMER None REFERENCES 1 Montanaro F Rosato R Gangemi M et al Survival of pleural malignant mesothelioma in Italy a population study Int J Cancer 2009 124.201-207 2 Taylor NO Paffenbarger GC A survey of current inlay casting techniques J Am Dent Assoc 1930 17.2058-2081 17.2058-2081 3 Dyer MR The possible adverse effects of asbestos in gingivectomy packs Br DentJ 1967 122.507 4 Council on Dental Therapeutics Council on Dental Materials and Devices Hazards of asbestos in dentistry J Am Dent Assoc 1976 92 777-778 5 Bakdash MB Frydman A. Asbestos in periodontal dressings a possible health hazard Quintessence Int Dent Dig 1976 7 61-65 448 AMERICAN JOURNALWILEY WILEY 6 Cutrigh DE Huget EF Brady JM Asbestos a subtle carcinogen in the dental laboratory Gen Dent 1980 46-50 Brune D Beltesbrekke H. Levels of methylmethacrylate formaldehyde and asbestos in dental workroom air Scand J Dent Res 1981 89.113-116 Cook A. Asbestos dressing Br Dent J. 2008 204.224 9. Fry C. An investigation into asbestos related disease in the dental industry Br DentJ 2009 515-516 10. De Vuyst P Vande Weyer R De Coster A et al Dental technician's pneumoconiosis A report of two cases Am Rev Respir Dis 1986 316-320 11 Choel L Grosgogeat B Bourgeois D Descotes J. Occupational toxic risks in dental laboratory technicians J Environ Med 2001 1-307-314 12 Radi S Dalphin JC Manzoni P Pernet D Leboube MP Viel JF Respiratory morbidity in a population of French dental technicians Occup Environ Med 2002 398-404 13. Sichletidis L Spyratos D Chloros D Michailidis K Fourkiotoul Pleural plaques in dentists from occupational asbestos exposure a report of three cases Am J Ind Med 2009 926-930 14 Reid AS Causton BE Jones JSP Ellis IO Malignant mesothelioma after exposure to asbestos in dental practice Letter Lancet 1991 338 696 15. Marinaccio A Binazzi A Bonafede M et al II Registro Nazionale dei Mesoteliomi Quinto Rapporto Roma INAIL 2015 p 261 16. Mensi C Termine L Canti Z et al The Lombardy Mesothelioma Register Regional Operating Centre ROC of National Mesothelioma Register organizational aspects in italian Epidemiol Prev 2007 31-283-289 17 Mens C De Matteis S Dallar~- B Riboldi L Bertazz~-PA Consonni D Incidence of mesothelioma in Lombardy Italy exposure to asbestos time patterns and future projections Occup Environ Med 2016 73.607-613 18 Nesti M Adamoli S Ammirabile F et al Linee guida per la rilevazionee la definizione dei casi di mesotelioma maligno e la trasmissione delle informazioni all'ISPESL da parte dei Centri Operativ Regionali Seconda Edizione Roma ISPESL https www.inail internet renamlineeguida2005 pdf accessed Oct 24 2016 2003 19. Choudat D Occupational lung diseases among dental technicians Tuber Lung Dis 1994 75 99-104 20 Davis DR Release of asbestos fibers during casting ring liner manipulation J Prosthet Dent 1995 74.294-298 MENSI ET AL 21. Jung H Airborne asbestos concentrations of dental laboratories in ome metropolitan city in Korean J Korean Continence Soc 2011 2 31-36 22. Ogus H Bourne R. Richard James Bourne Obituary BrJ Dent 2007 203 715 23. Liu G Cheresh P Kamp DW Molecular basis of asbestos lung disease Annu Rev Pathol 2013 161 187 24. Choudat D Triem S Weili B et al Respiratory symptoms lung function and pneumoconiosis among self employed dental techniclans Br J Ind Med 1993 443-449 25 Rasmuson JO Roggli VL Boelter FW Rasmuson EJ Redinger CF Cumulative retrospective exposure assessment REA as a predictor of amphibole asbestos lung burden validation procedures and results for Industrial hygiene and pathology estimates Inhal Toxicol 2014 26-1-13 26. Churg A Wright JL Persistence of natural mineral fibres in human lungs an overview Environ Perspect 1994 229-233 27. Tossavainen A. Asbestos asbestosis and cancer the Helsinki criteria for diagnosis and attribution Scand J Work Environ Health 1997 311-316 28. Wolff H Vehmas T Oksa P Rantanen J Vainio H Asbestos asbestosis and cancer the Helsinki criteria for diagnosis and attribution 2014 recommendations Scand J Work Environ Health 2015 5-15 29. Warnock ML Wolery G. Asbestos bodies or fibres and the diagnosis of asbestosis Environ Res 1987 44-9-44 30. Baker DB Limitations in drawing etiologic inferences based on measurement of asbestos fibers from lung tissue Ann NY NY Acad Sci 1991 61-71 31. Karjalainen A Nurminen M Vanhala E Vainio H Anttila S Pulmonary asbestos bodies and asbestos fibers as indicators of exposure ScandJ Work Environ Health 1996 34-38 How to cite this article Mensi C Ciullo F Barbieri GP et al Pleural malignant mesothelioma in dental laboratory technicians A case series Am J Ind Med 443-448 https://doi.org/10 ajim.22716