Journal of Conservative Dentistry
Home About us Editorial Board Instructions Submission Subscribe Advertise Contact e-Alerts Login 
Users Online: 924
Print this page  Email this page Bookmark this page Small font sizeDefault font sizeIncrease font size
 


 
Table of Contents   
ORIGINAL ARTICLE  
Year : 2016  |  Volume : 19  |  Issue : 4  |  Page : 343-346
A systematic review of randomized controlled trials on sterilization methods of extracted human teeth


1 Private Dental Practitioner and Consultant Endodontist, Tirunelveli, TamilNadu, India
2 Faculty of Dentistry, SEGi University, No. 9, Jalan Teknologi, Kota Damansara PJU5 Selangor, Malaysia

Click here for correspondence address and email

Date of Submission06-Mar-2016
Date of Decision17-May-2016
Date of Acceptance10-Jun-2016
Date of Web Publication18-Jul-2016
 

   Abstract 

Aim of this Study: The aim was to evaluate the efficiency of different sterilization methods on extracted human teeth (EHT) by a systematic review of in vitro randomized controlled trials.
Methodology : An extensive electronic database literature search concerning the sterilization of EHT was conducted. The search terms used were “human teeth, sterilization, disinfection, randomized controlled trials, and infection control.” Randomized controlled trials which aim at comparing the efficiency of different methods of sterilization of EHT were all included in this systematic review.
Results : Out of 1618 articles obtained, eight articles were selected for this systematic review. The sterilization methods reviewed were autoclaving, 10% formalin, 5.25% sodium hypochlorite, 3% hydrogen peroxide, 2% glutaraldehyde, 0.1% thymol, and boiling to 100°C. Data were extracted from the selected individual studies and their findings were summarized.
Conclusion: Autoclaving and 10% formalin can be considered as 100% efficient and reliable methods. While the use of 5.25% sodium hypochlorite, 3% hydrogen peroxide, 2% glutaraldehyde, 0.1% thymol, and boiling to 100°C was inefficient and unreliable methods of sterilization of EHT.

Keywords: Autoclaving; extracted human teeth; formalin; sterilization methods; systematic review

How to cite this article:
Western J S, Dicksit DD. A systematic review of randomized controlled trials on sterilization methods of extracted human teeth. J Conserv Dent 2016;19:343-6

How to cite this URL:
Western J S, Dicksit DD. A systematic review of randomized controlled trials on sterilization methods of extracted human teeth. J Conserv Dent [serial online] 2016 [cited 2019 Dec 15];19:343-6. Available from: http://www.jcd.org.in/text.asp?2016/19/4/343/186457

   Introduction Top


Extracted human teeth (EHT) are routinely used by students for performing preclinical exercises, for preparing ground sections, and for research.[1] Since they harbor bloodborne pathogens and are a potential source of infection, they must be sterilized before use.[2] The efficiency of several sterilization methods is comparatively evaluated in a number of randomized controlled trials. There exists a need to systematically summarize the current knowledge regarding this issue.

The objective of this study was to systematically organize all the studies evaluating the efficiency of different sterilization methods of human teeth and to determine efficient methods by summarizing the findings from individual studies.


   Methodology Top


This systematic review was conducted following the preferred reporting items for systematic reviews and meta-analyses guidelines to ensure optimum quality.[3],[4] An extensive literature search concerning the sterilization of EHT was conducted in electronic databases of PubMed, LILACS, Scopus, Google Scholar, and hand searching reference lists from relevant journals. The keywords used were “Human Teeth, Sterilization, Disinfection, Randomized Controlled Trials, and Infection Control.” The search resulted in a total of 1618 articles. After removal of irrelevant articles and duplicates, the abstracts of the selected 43 articles were screened. Studies evaluating the effect of different sterilization methods on the physical and chemical composition of tooth structure were all eliminated. For the remaining twenty articles, full text was retrieved and they were screened based on the following predetermined study eligibility criteria.

Inclusion criteria

Studies that were (1) done from 1990 to 2015, (2) in English, (3) randomized controlled trials, (4) done in EHT, (5)in vitro studies, (6) comparing the efficacy of at least one method of sterilization of EHT with that of a control group.

Exclusion criteria

studies that were (1)in vivo studies, letters, comments, editorials, questionnaire surveys, case reports, proceedings, personal communications, and any type of literature reviews, (2) done in nonhuman teeth, (3) with no control group, (4) with outcome measures not defined clearly.

A flowchart diagram of the study selection process is given in [Figure 1]. List of studies with references and their reasons for exclusion as numbered in the study exclusion criteria is given in [Table 1].
Figure 1: A flowchart diagram of the study selection process

Click here to view
Table 1: List of studies and their reasons for exclusion as numbered in the exclusion criteria

Click here to view



   Results Top


[Table 2] summarizes the method of data collection, synthesis, and extraction from the eight selected primary studies. In this systematic review, percentile efficiency of each sterilization method is calculated from the total number of samples tested and the total number of samples which had no microbial growth after being subjected to the particular sterilization method.
Table 2: The method of data synthesis and data extraction from the selected primary studies

Click here to view


Autoclaving method and usage of 10% formalin showed 100% efficient sterilization. The other methods of sterilization (5.25% sodium hypochlorite, 3% hydrogen peroxide, 2% glutaraldehyde, 0.1% thymol, and boiling to 100°C) all showed inefficient sterilization, percentile efficiency of which are also presented in [Table 2].


   Discussion Top


Extracted teeth are prone to colonization by potentially pathogenic bacteria and need to be sterilized properly [23] before use in teaching laboratory and research. Scientific literature has documented various randomized controlled trials comparing various methods of sterilization of EHT. Although several narrative literature reviews [8],[9],[24] were done in the past, there are no systematic reviews done in this field. The objective of this systematic review was to identify all randomized controlled trials evaluating the efficiency of different sterilization methods of EHT, to determine the total number of trials done to date, to assess the quality of those trials, to determine whether a particular sterilization method works better than the others based on the findings from the primary individual studies, and to identify gaps in knowledge where new trials are still needed.

The present systematic review concluded that autoclaving and 10% formalin are very efficient and reliable methods of sterilization of EHT; 5.25% sodium hypochlorite, 3% hydrogen peroxide, 2% glutaraldehyde, 0.1% thymol, and boiling to 100°C are all inefficient and unreliable methods of sterilization of EHT.

While the data obtained from this review are valuable, its application to practice may be limited because these methods of sterilization reviewed have their own set of advantages and disadvantages. Autoclaving and 10% formalin do not alter the feel and cutting characteristics; therefore, they do not compromise the learning experience when used for preclinical exercises.[22] Autoclaving causes disruption of collagen [25] and denature the organic component in dentin,[26] which can alter the hybrid layer after resin penetration. Therefore, autoclaving makes the teeth not suitable for use inin vitro studies testing the microhardness,[26] bond strength, and microleakage.[25] The tooth containing dental amalgam restorations should not be autoclaved because the vaporized mercury [22] can be inhaled subjecting the patients and dental personnel to health risk.[27] Formalin causes stabilization of the collagen preventing their collapse, which allows increased mechanical interlocking of the restorative material to the dentin. This makes it unsuitable for use inin vitro microleakage and bond strength research.[24],[25] Formalin is a skin and eyes irritant,[10] cytotoxic, genotoxic,[28] and carcinogenic.[29] Therefore, although being an efficient sterilization method, its use is discontinued as it poses a major health hazard.

Limitations of this systematic review are (1) preferable inclusion of articles in English, (2) restricted time frame from 1990 to 2015, (3) other methods of sterilization including gamma radiations, chemiclave, dry heat, microwave, benzalkonium chloride, 0.5% chloramine, 2% sodium azide, iodophor, phenol, alcohol, and antibiotics could not be included because of lack of sufficient number of studies carried out using these methods for effective comparison, (4) perceived weakness of such disinfection efficiency evaluation studies may be due to inherent variations in the microbial composition, microbial load, and biofilm matrix composition [18] between individual tooth used in different studies, (5) it is not coupled with a meta-analysis because there is a mix of comparisons of different sterilization methods with diverse outcomes in the primary studies, (6) although the concentration of disinfectant solutions used were all standardized while summarizing this systematic review, the time limit of each sterilization method used in the primary studies could not be standardized.

Excluding gamma radiations, all the other sterilization methods tested so far resulted in changes in properties of tooth structure.[14] Therefore, there exists a need to find out a feasible and efficient sterilization method suitable for use in teeth to be used forin vitro studies. Further, this review brings into light the need for new ideas and methods for sterilization of root canal space of extracted teeth to be used in preclinical endodontics.


   Conclusion Top


This systematic review concluded that autoclaving and 10% formalin were 100% efficient and reliable methods of sterilization of EHT; autoclaving method may be the definitive method for sterilizing teeth used for preclinical conservative exercises. Usage of 10% formalin, although effective, is discouraged due to associated health risks. 5.25% sodium hypochlorite, 3% hydrogen peroxide, 2% glutaraldehyde, 0.1% thymol, and boiling to 100°C are all inefficient and unreliable methods of sterilization of EHT. This systematic review also brings into light the need for sterilization methods and protocol needed for sterilization of extracted teeth to be used for preclinical endodontics and inin vitro studies.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
   References Top

1.
Sandhu SV, Tiwari R, Bhullar RK, Bansal H, Bhandari R, Kakkar T, et al. Sterilization of extracted human teeth: A comparative analysis. J Oral Biol Craniofac Res 2012;2:170-5.  Back to cited text no. 1
    
2.
Tate WH, White RR. Disinfection of human teeth for educational purposes. J Dent Educ 1991;55:583-5.  Back to cited text no. 2
    
3.
Moher D, Liberati A, Tetzlaff J, Altman DG; PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: The PRISMA Statement. Open Med 2009;3:e123-30.  Back to cited text no. 3
[PUBMED]    
4.
Moher D, Shamseer L, Clarke M, Ghersi D, Liberati A, Petticrew M, et al. Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015 statement. Syst Rev 2015;4:1.  Back to cited text no. 4
[PUBMED]    
5.
Amith HV, D'cruz AM. Attitude and practice on handling of extracted teeth for educational use among the students of a dental college in Southern India. Int J Med Dent 2014;4:147-53.  Back to cited text no. 5
    
6.
Hashemipour MA, Mozafarinia R, Mirzadeh A, Aramon M, Nassab SA. Knowledge, attitudes, and performance of dental students in relation to sterilization/disinfection methods of extracted human teeth. Dent Res J (Isfahan) 2013;10:482-8.  Back to cited text no. 6
    
7.
Smitha D, Tijare MS, Amith HV, Gujjar KR, Sharma R. Knowledge, attitude and practice regarding handling of extracted human teeth among students of a dental college in Bhopal. J Indian Assoc Public Health Dent 2014;12:276-82.  Back to cited text no. 7
  Medknow Journal  
8.
Albrecht L, Ferreira EL, Passos ML, Cecchetti RT. Teeth processing in human teeth bank – Proposal of protocol. RSBO 2013;10:386-93.  Back to cited text no. 8
    
9.
Viana PS, Machado AL, Giampaolo ET, Pavarina AC, Vergani CE. Disinfection of bovine enamel by microwave irradiation: Effect on the surface microhardness and demineralization/remineralization processes. Caries Res 2010;44:349-57.  Back to cited text no. 9
    
10.
Cuny E, Carpenter WM. Extracted teeth: Decontamination, disposal and use. J Calif Dent Assoc 1997;25:801-4.  Back to cited text no. 10
    
11.
White RR, Hays GL. Failure of ethylene oxide to sterilize extracted human teeth. Dent Mater 1995;11:231-3.  Back to cited text no. 11
    
12.
Abdul-Rahman Gh Y, Al-Ashou WMO, Shukur AM. Disinfection of extracted teeth for dental researches. Al-Rafidain Dent J 2010;10:158-61.  Back to cited text no. 12
    
13.
Tabrizizadeh M, Abrisham M, Dehghan Marvasti F. Comparison of different techniques for disinfection of teeth internal space in preclinical teaching. J Dent Med 2009;22:120-4.  Back to cited text no. 13
    
14.
White JM, Goodis HE, Marshall SJ, Marshall GW. Sterilization of teeth by gamma radiation. J Dent Res 1994;73:1560-7.  Back to cited text no. 14
    
15.
Pantera EA Jr., Schuster GS. Sterilization of extracted human teeth. J Dent Educ 1990;54:283-5.  Back to cited text no. 15
    
16.
Tijare M, Smitha D, Kasetty S, Kallianpur S, Gupta S, Amith H. Vinegar as a disinfectant of extracted human teeth for dental educational use. J Oral Maxillofac Pathol 2014;18:14-8.  Back to cited text no. 16
[PUBMED]  Medknow Journal  
17.
Chandki R, Maru R, Gunwal M, Garg A, Mishra A. A comparison of different methods for disinfection or sterilization of extracted human teeth to be used for dental education purposes. World J Dent 2013;4:29-31.  Back to cited text no. 17
    
18.
Hope CK, Griffiths DA, Prior DM. Finding an alternative to formalin for sterilization of extracted teeth for teaching purposes. J Dent Educ 2013;77:68-71.  Back to cited text no. 18
    
19.
Ghosh A, Chowdhury S. Sterilization and disinfection of extracted human teeth for institutional use. Int J Clin Dent Sci 2013;4:9-12.  Back to cited text no. 19
    
20.
Nikita VL, Vidya BS, Sham SB. Disinfection methods of extracted human teeth. J Oral Health Community Dent 2007;1:27-9.  Back to cited text no. 20
    
21.
Kumar M, Sequeira PS, Peter S, Bhat GK. Sterilisation of extracted human teeth for educational use. Indian J Med Microbiol 2005;23:256-8.  Back to cited text no. 21
[PUBMED]  Medknow Journal  
22.
Dominici JT, Eleazer PD, Clark SJ, Staat RH, Scheetz JP. Disinfection/sterilization of extracted teeth for dental student use. J Dent Educ 2001;65:1278-80.  Back to cited text no. 22
    
23.
Beatriz HS, Marili DA, Vania PD, Rosimeire TR, Edvaldo AR. Contaminant microbiota associated to extracted human teeth. Rev Clin Pesqui Odontol 2004;1:19-21.  Back to cited text no. 23
    
24.
DeWald JP. The use of extracted teeth forin vitro bonding studies: A review of infection control considerations. Dent Mater 1997;13:74-81.  Back to cited text no. 24
    
25.
Attam K, Talwar S, Yadav S, Miglani S. Comparative analysis of the effect of autoclaving and 10% formalin storage on extracted teeth: A microleakage evaluation. J Conserv Dent 2009;12:26-30.  Back to cited text no. 25
[PUBMED]  Medknow Journal  
26.
Salem-Milani A, Zand V, Asghari-Jafarabadi M, Zakeri-Milani P, Banifatemeh A. The effect of protocol for disinfection of extracted teeth recommended by center for disease control (CDC) on microhardness of enamel and dentin. J Clin Exp Dent 2015;7:e552-6.  Back to cited text no. 26
    
27.
Centers for Disease Control and Prevention (CDC). Guidelines for infection control in dental health-care settings-2003. MMWR Recomm Rep 2003;52:1-61.  Back to cited text no. 27
    
28.
Neghab M, Soltanzadeh A, Choobineh A. Respiratory morbidity induced by occupational inhalation exposure to formaldehyde. Ind Health 2011;49:89-94.  Back to cited text no. 28
    
29.
Cogliano V, Grosse Y, Baan R, Straif K, Secretan B, El Ghissassi F, et al. Advice on formaldehyde and glycol ethers. Lancet Oncol 2004;5:528.  Back to cited text no. 29
    

Top
Correspondence Address:
Dr. J Sylvia Western
600, Main Road, Western Electricals, Tisaiyanvillai, Tirunelveli, Tamil Nadu
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0972-0707.186457

Rights and Permissions


    Figures

  [Figure 1]
 
 
    Tables

  [Table 1], [Table 2]



 

Top
 
 
 
  Search
 
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Email Alert *
    Add to My List *
* Registration required (free)  
 


    Abstract
   Introduction
   Methodology
   Results
   Discussion
   Conclusion
    References
    Article Figures
    Article Tables

 Article Access Statistics
    Viewed1487    
    Printed12    
    Emailed0    
    PDF Downloaded149    
    Comments [Add]    

Recommend this journal