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Acta Odontológica Latinoamericana

versão On-line ISSN 1852-4834

Acta odontol. latinoam. vol.29 no.3 Buenos Aires dez. 2016



Fungal contamination and disinfection of dental chairs, Teresina, Piaui, Brazil


Antônio I. V. de Almondes1, Jhonatta O. P. de Araújo1, Larissa Mendes de Sirqueira Amaral1, Renandro C. Reis1, Jhonatas C. S. Porto1, João Batista Teles2, Thiago L. Monte2, Iraci de M.S. Noleto2, Tanit C. Santos2, Ivonizete P. Ribeiro1, Mitra Mobin1

1 Laboratory Research, Centro Universitário de Saúde, Ciências Humanas e Tecnológicas do Piauí
2 Dental Clinic, Centro Universitário de Saúde, Ciências Humanas e Tecnológicas do Piauí.

CORRESPONDENCE Dra. Mitra Mobin Centro Universitario da Saude, Ciencias Humanas e Tecnologicas do Piaui. Rua Vitorino Orthiges Fernandes, 6123 - Uruguai Teresina Piaui, Brasil. CEP: 64073505


The aim of this study was to analyze fungal contamination on dental chairs at the clinic of a Higher Education Institution in TeresinaPI, Brazil, and to evaluate the effectiveness of different disinfectants: 70% alcohol and 1% sodium hypochlorite. We selected the five sites with most contact between patient and chair: headrest, backrest, armrests, seat and foot rest. Samples were collected from these sites on 14 chairs and inoculated in agar Sabouraud culture medium containing chloramphenicol. Pathogenic fungi were isolated from all sampling sites on the chairs. Highest frequencies were found on footrest, followed in decreasing order by seat, backrest, armrests and headrest. Fourteen species of filamentous fungi were identified, belonging to the genera Alternaria, Aspergillus, Cladosporium, Curvularia, Drechslera, Fusarium, Penicillium and Paecillomyces. After sampling, seven chairs were disinfected with 70% alcohol and seven with 1% sodium hypochlorite, and samples were taken again using the same procedure. No fungal growth was detected following disinfection with sodium hypochlorite, which was clearly more effective than alcohol, after which there was still fungal growth. This study highlights the need for the biosafety protocol to include cleaning and disinfection of dental chairs with 1% sodium hypochlorite after each attendance in order to prevent crossinfection.

Key words: Dental equipment; Fungi; Cross infection; Disinfection.


Contaminação de fungos e desinfecção em cadeiras odontologicas, Teresina, Piauí, Brasil

O objetivo deste estudo foi analisar contaminação fúngica em cadeiras odontológicas na clínica de uma Instituição de Educação Superior em TeresinaPI, Brasil, e avaliar a efetividade de diferentes desinfetantes: álcool 70% e hipoclorito de sódio 1%. Nós selecionamos os cinco locais com maior contato entre o paciente e a cadeira: encosto da cabeça, das costas, dos braços, assento e encosto dos pés. As amostras foram coletadas destes locais das 14 cadeiras e inoculadas em meio de cultura agarSabouraud contendo cloranfenicol. Fungos patogênicos foram isolados de todos os locais de amostragem das cadeiras. As frequências mais altas foram encontradas no encosto dos pés, seguido em ordem decrescente pelo assento, encosto das costas, dos braços e encosto da cabeça. Quatorze espécies de fungos filamentoso foram identificados, pertencente aos gêneros Alternaria, Aspergillus, Cladosporium, Curvularia, Drechslera, Fusarium, Penicillium e Paecillomyces. Após a coleta, sete cadeiras foram desinfe tadas com álcool 70% e sete com hipoclorito de sódio 1%, e as amostras foram colhidas novamente usando o mesmo procedimento. Não foi detectado crescimento fúngico após desinfecção com hipoclorito de sódio, que foi claramente mais efetivo que o álcool, do qual ainda houve crescimento fúngico.Este estudo destaca a necessidade da inclusão no protocolo de biossegurança a limpeza e desinfecção das cadeiras odontológicas com o hipoclorito 1% após cada atendimento, a fim de prevenir infecções cruzadas.

Palavras chave: Equipamentos odontológicos; Fungos; Infecção cruzada; Desinfecção.



Dental offices harbor various forms of contamination by microorganisms, including fungi, exposing dentists to the risk of infections transmitted in various ways, including direct contact with infectious lesions and secretions; indirect contact by means of microorganisms on instruments, equipment and rigid surfaces; aerosols, and interpersonal contact 1,2. Highspeed handpieces can spread fungi by creating aerosols that settle on surfaces and equipment such as chair, spotlight, dental equipment and instruments. This is particularly risky when airconditioning further aggravates the occurrence of fungi and the area is not cleaned regularly 3,4.
Biosafety in dentistry includes a set of actions to protect staff and patients in a clinical setting, including ergonomic practices, control of physical and chemical hazards, use of specific protocols, and appropriate handling of products and equipment, in addition to the sterilization process, disinfection, antisepsis, use of barriers and individual protective equipment (IPE).5 Controlling disease transmission is a challenge to dentists, since the oral cavity contains microorga nisms, many of which can cause diseases ranging from a mild cold to pneumonia and from tuberculosis to herpes. These infections may be transmitted by contaminated saliva, blood, fluid from the gingival sulcus, and even the patient's respiratory secretions 2,6. This study analyzed fungal contamination on dental chairs at the clinic in a Higher Education Institution in TeresinaPI, and evaluated the effectiveness of two disinfecting agents: 70% alcohol and 1% sodium hypochlorite.


This was a quantitative and descriptive study performed at the Research Laboratory of the University Center UNINOVAFAPI in TeresinaPI from January to November 2015, after authorization from the management.
Samples were collected from 14 (93.3%) of the dental chairs by rubbing sterile swabs soaked in
saline on the five sites selected: headrest, backrest, armrests, seat and footrest. From each sample, 100μL were inoculated in Petri dishes containing Sabouraud Dextrose agar (DifcoTM) culture medium plus chloramphenicol (0.05g/L) and incubated at room temperature to enable the growth of the fungal colonies. After growth of the colonies, microcultures were mounted for recognition of species using identifica tion keys previously described7,8.
The same procedure was used to test the disinfectant efficacy of 70% ethanol and 1% sodium hypochlorite. For statistical analysis, the chisquare test for goodness of fit was applied with a significance level (α) of 5%.



We identified 14 species belonging to the genera Alternaria, Aspergillus, Cladosporium, Curvularia, Drechslera, Fusarium, Penicillium and Paecillomyces (Fig.1).

Fig. 1:
Micromorphology of filamentous fungi isolated in dental chairs of a Higher Education Institution (HEI): A Penicillium oxalicum;B Aspergillus flavus;C Fusarium aff. incarnatum;D Aspergillus carnus;E Drechslera biseptata; F Cladosporium cladosporioides;G Aspergillus niger; H Curvularia clavata; I Curvularia brachyspora; J Penicillium piceum; K Cladosporium oxysporum; L Penicillium decumbens.

Aspergillus niger was the most frequent species, being found at all sites of the dental chair. Curvularia clavata and Alternaria infectoria were identified from three site seach (Table 1).

Table 1: Presence of fungal species per dental chair site at a clinic at a Higher Education Institution (HEI).

The region with the highest level of contamination was footrest, with 50.0%, followed by seat (42.9%), backrest and armrest (35.7% each), and finally headrest (21.4%) (Table 2). Following disinfection with 70% alcohol, fungal growth occurred in the samples from all sites, whereas following disinfection with 1% hypochlorite, no fungal growth was observed.

Table 2: Frequency of fungi on the dental chair, Teresina - PI, 2015.


Dental chairs can become contaminated by fungi in several ways: via air conditioning, failure to apply biosafety standards, lack of internal protocols and/or failure to comply with them, and invasive procedures performed during treatment.
All the species found in this study are pathogenic and may cause infections ranging from cutaneous to systemic infections. Aspergillus niger, the most common species in this study, causes pulmonary aspergillosis, endophthalmitis, endocarditis, perito nitis and cutaneous infections7. The table 3 shows the main diseases caused by the species found in this study. There is high risk of crossinfection in the dental office as a result of the invasive procedures performed and environmental contamination by biological agents or bioaerosols which may come from internal or external air conditioning, furniture and carpets 2, 3, 9. Mobin and Salmito found the following pathogenic fungal genera in air conditioners of an Intensive Care Unit (ICU): Acremonium, Aspergillus, Paecillomyces, Penicillium, Trichoderma, Cladosporium, Curvularia and Nigrospora. Several other studies show that air conditioners provide a favorable environment for fungal growth, thus actively contributing to worsening health status of patients, whether in ICUs or dental offices 10.

Table 3: Disease occurrence caused by fungi isolated from dental chairs from a HEI in Teresina - PI.

Sousa and Fortuna studied air conditioned dental offices in Bahia, and in all cases found the highest frequency of microorganisms such as Aspergillus and Fusarium near the spittoon 3. This might be due to highspeed drills spreading microorganisms through aerosols, which may become attached to equipment and accessories as well as remaining airborne. A study comparing microbial load between a dental clinic and a nondental public area found that the risk in the dental clinic may be greater than in the public area due to the diversity of microorganisms, susceptibility of the host and exposure time. In addition to bacteria, they found fungi, as Aspergillus nigerand Aspergillus flavus 11. Another study reports high number of aerosol and bioaerosol particles during dental procedures and a variety of microorganisms present in a dental office, including the fungal genera Penicillium, Cladosporium and Alternaria 9.
Internal air conditioning also contributes to proliferation and spread of fungi in dental offices. Recirculating air and airing the room after each patient is recommended to prevent accumulation of fungal spores 10.
After disinfecting the chairs with 70% alcohol, there was still fungal growth from the samples, showing the method to be less effective than use of 1% sodium hypochlorite. Although alcohol is a commonly used disinfectant, the results of this and of other studies suggest that it is ineffective against fungi 12. Regarding the action of alcohol on bacteria, several studies claim that its effect is more bacteriostatic than bactericidal. Moreover, there are studies that claim that the use of 70% alcohol is inappropriate for removing saliva layers on instruments, and it has been demonstrated that even water is more appropriate than alcohol for removing blood and organic matter 13. The biosafety protocol should therefore include cleaning and disinfecting chairs with 1% hypochlorite after each patient in order to prevent crossinfection.


The authors thank Edivan Pereira da Silva, responsible for the microbiology laboratory, for technical support to the research.


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