Journal of Dental Implants
   About JDI | Editorial | Search | Ahead of print | Current Issue | Archives | Instructions | Subscribe | Login 
Users Online: 169  Wide layoutNarrow layoutFull screen layout Home Print this page  Email this page Small font size Default font size Increase font size

Table of Contents
Year : 2016  |  Volume : 6  |  Issue : 2  |  Page : 51-56

Implant failure: A dentist's nightmare

Department of Oral Pathology and Microbiology, Sinhgad Dental College and Hospital, Pune, Maharashtra, India

Date of Web Publication15-Mar-2017

Correspondence Address:
Madhura Avinash Kate
150, Anand Avinash Niwas, S.T. Road, Dapodi, Pune - 411 012, Maharashtra
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0974-6781.202154

Rights and Permissions

Dental implants are commonly used in clinical situations for replacement of natural teeth. Despite many advances in materials, techniques, and implant design, implant failure is a significant concern for the dentist and patient. Peri-implantitis and lack of osseointegration are considered to be the major factors leading to implant failure. Occlusal overloading, medical status of the patient, smoking, and implant characteristics are among the other causes for implant failure. The purpose of this concise review is to discuss the etiology of implant failures by highlighting the various classification put forth by different authors and formulating a new classification.

Keywords: Classification, fracture, implant failure, osseointegration, overloading, peri-implantitis, prosthesis, smoking

How to cite this article:
Kate MA, Palaskar S, Kapoor P. Implant failure: A dentist's nightmare. J Dent Implant 2016;6:51-6

How to cite this URL:
Kate MA, Palaskar S, Kapoor P. Implant failure: A dentist's nightmare. J Dent Implant [serial online] 2016 [cited 2023 Jun 10];6:51-6. Available from:

   Introduction Top

An implant is “a graft or insert set firmly or deeply into or onto alveolar process that may be prepared for its insertion.” Implants are used for single tooth replacements, partially edentulous arches and for completely edentulous arches. They are inert, alloplastic materials most commonly made of titanium or titanium alloy or vitalinium.[1] Alternatively, ceramics such as hydroxyapatite, bioglass, or aluminum oxides can be used.[2] Depending on their placement within the bone, they are classified into epiosteal, endosteal, and transosteal.[2],[3] The most common one is endosteal (screw shaped or cylindrical). An implant consists of an implant body which is placed within the bone, implant screw placed on the superior surface of the body to which is attached the healing cap. Abutments are placed over the implant body which provides retention to the prosthesis.[1],[2] Implants are placed into the bone either in 1 stage or 2 stage surgery. In spite of taking many precautions and surgical precision, implant failures do occur attributing to certain factors.

   Review of Literature Top

The aim of this article is to study the various causes of implant failure by focusing on the various classifications given from time to time. Implant failure is caused by a number of factors which include peri-implantitis, absence of osseointegration, and implant fracture. It may also be caused due to surgical trauma, micromotion, and overloading.[4] Over the years, differed classifications of Implant failures have been proposed by various authors [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6].
Figure 1: Classification of Implant Failures as stated by Nallaswamy [1]

Click here to view
Figure 2: Classification of Implant Failures as stated by Rosenberg et al.[5]

Click here to view
Figure 3: Classification of Implant Failures as given by Esposito et al.[6]

Click here to view
Figure 4: Classification of implant failures as stated by Truhlar [5] and Tonetti and Schmid

Click here to view
Figure 5: Classification of implant failures given by Matukas [5]

Click here to view
Figure 6: Classification of implant failures as given by El Askary et al.[5]

Click here to view

Working classification

Compiling the various classification systems given from time to time, we have put forward a new working classification which divides implant failures broadly into early and late failures. They are further classified based on etiology, personnel responsible, failure mode, and biological causes [Table 1].
Table 1: Working classification

Click here to view

   Discussion Top

Improper selection of patient, poor oral hygiene due to bacterial plaque accumulation, improper prosthetic restoration, debris retention, and bone preparation without the use of coolants have been contributing factors in the breakdown of successfully placed implants.[7]

Early failures

Early failures occur soon after placement of implants in the bone which is between few weeks to months. They interfere with the healing process or cause altered healing.[2],[3],[8]

Implant selection

Etiologically, improper implants such as short implants cause implant failure due to unfavorable crown root ratio.[3],[9] In a study carried out by Bahat on treatment planning and placement of implants in posterior maxilla in the year 1993, 732 placed implants in posterior maxilla of partially edentulous patients reported a failure rate of 9.5% for 7 mm implants as compared to 3.8% for all other lengths.[10] Similarly, implants with a smaller diameter are less apt to withstand stresses leading to fracture of the implant components. Bahat and Handelsman compared the clinical outcomes of the placement of different combinations of implants at one site in the posterior areas and found the failure rate for all 5 mm implants was 2%–3%, and that for all double implants was 1%–2%.[11] The superstructure tends to loosen in the mouth due to conical screw design.[9] Implant properties such as surface roughness, impurities help to retain the implant in the bone, thus playing an important role in implant success.[3] As implant characteristics are crucial in success of an implant, the type of bone which receives an implant is equally significant.

Bone type

Dense compact bone and porous compact bone found in the anterior mandible are more favorable as they hold the implant firmly in the socket. In contrast to this, porous and trabecular bone found in the posterior maxilla decrease the stability of the implant in the bone.[12],[13] Jaffin and Berman (1991), in their 5-year analysis, reported that as many as 35% of all implant failures occurred in porous trabecular bone due to its thin cortex.[14] Placing the implant in immature bone grafted sites increases the chances of failures.

Surgical criteria

Surgical accuracy is an important criterion for a successful implant. This depends on axial placement of implant, spacing between adjacent implants and its initial stabilization in the bone. Buccally placed implants jeopardize the buccal cortical plate. Similarly, lingually placed implant interferes with tongue movements hampering speech.[6] Less space between two implants causes injury to interdental bone leading to bone loss.[1] On the other hand, if the spacing is more than required, additional cantilevers are placed which increase the stress on supporting implants, leading to fracture of implants, thereby its failure.[6] Atilla Sertgoz et al. in 1996 reported that maximum stresses were concentrated at the most distal bone/implant interface, located on the loaded side of terminal implant, increasing cantilever length resulted in increased stress value at bone-implant interface.[15] Over preparation of the bone site due to excessive in and out motion decreases the density of bone. Use of dense bone drills in low-density bone decreases the bone quality.[8] Excess heating of bone causes bone necrosis [9] (47° for more than 1 min). Salonen et al. (1993) found that 5.8% of implants were lost due to failures of osseointegration caused by excessive heating of bone.[16] Irrigation helps to reduce the chances of bone necrosis.[9]

Surgical conditions

Maintaining sterile conditions during the surgical procedure is of utmost importance. Saliva, perioral skin, unsterile instruments, contaminated gloves, operating room air, or air expired by the patient, all interfere in the surgical procedure leading to contamination of the implant site, causing infection in the implant site.

Prosthetic considerations

Prosthetic rehabilitation and occlusal adjustments should be taken into consideration for a successful implant. Fumihiko Watanabe et al. in 2002 reported that an implant was placed in an incorrect inclination in spite of cooperation between the surgeon and prosthodontist. This failure suggested the necessity of clearly presenting the prosthodontic aspect of treatment to each member of the team before surgical treatment is rendered.[17] Distribution of forces enhances the success of implant. Increased force on one implant leads to prosthetic component breakage.[3],[8] Hence, excessive load on single implant should be avoided. Misfit of the implant leads to constant tension in the components which leads to screw loosening or fracture.[3],[8] Robert L. Simon in 2003 concluded that the implant failure rate was 4.6% with complications of abutments screw loosening (7%).[18] Poor implant design and excessive loading of implant (especially cantilever abutments) increase the failure chances.[8] Greater the cantilever distance, greater the chances of failure.[1],[8]

Late failures

As certain factors are responsible for causing early failures, there are a different set of factors which cause delayed failures. These failures arise from pathologic processes in previously osseointegrated implants. These are mostly associated with medical status of the patient. They are categorized as host factors.

Host factors

Patients with diabetes experience delayed wound healing which impairs osseointegration process.[4],[9],[13] Uncontrolled diabetes leads to implant failure. Fiorellini et al. (2000)[19] demonstrated a lower success rate of only 85% in patients with diabetes, while Olson et al. (2000)[20] found that the duration of diabetes had an effect on implant success: more failures occurred in patients who had diabetes for longer periods.[13] In osteoporotic and arthritic conditions, density of bone is adversely affected. This leads to porous bone. Such bone is unsuitable for implant success.[4],[13] John C. Keller et al. in 2004 have reported that osteoporosis-like bone conditions affect the osseointegration characteristic of implant.[21] Overweight is a metabolic syndrome which leads to increase in peri-implant inflammations which in turn affect implant prognosis.[4] A study carried out on implants, and relative risk factors stated that increasing age was also a major risk factor.[13] Compared to patients younger than 40, patients in the range of 60–70 years had a higher risk of implant failure.[22]

Tissue abuse and parafunctional habits

Tissue abuse habits, parafunctional habits, and psychological disorders have a detrimental effect on implant success.[3] Smoking is associated with significantly higher levels of bone loss. It reduces the density of bone which interferes with osseointegration, leading to increase the failure rate.[4],[13] A longitudinal study by Lambert et al. (2000) found more failures in patients who smoked, and Bain and Moy (1993) observed that a significantly greater percentage of failures implant occurred in smokers (11.3%) than in nonsmokers (4.8%).[13] Based on the studies carried out by Dror Twito and Paul Sade between the years 1999 and 2008 in Israel, it has been proved that 4.2% of implants, i.e., 321 out of 7680 implants failed due to smoking which included passive smoking as well.[23] Parafunctional habits such as bruxism increase the occlusal stress on implants. It leads to fracture of implants causing failures.[9] Glauser et al., evaluated 41 patients who received 127 immediately loaded implants. Their results showed that implants in patients with a parafunctional habit (bruxers) were lost more frequently than those placed in patients with no parafunction (41% vs. 12%).[24] Cognitive difficulty, mental retardation, and lack of support interfere with surgical procedures. Implant success is adversely affected due to psychological disorders.[3]


Radiotherapy is provided to patients suffering from maxillary and mandibular tumors. It causes osteoradionecrosis of bone which decreases the volume of bone, thus interfering with osseointegration.[4],[13] Reported success rate is only about 70%, long-term studies are limited, but Jacobsson et al. (1988) showed increasing implant loss over time due to radiation.[25]

Personnel responsible (early failures)

Placement of an implant is a surgical procedure carried out cumulatively by a periodontist, prosthodontist, and an oral surgeon.[3] Extraction of natural tooth, assessment of bone quality and quantity, periodontal health as well as systemic condition of the patient are all assessed by periodontist and an oral surgeon. Prosthodontist takes care of the implant design, prosthesis, and occlusal scheme. Any discrepancy in any of these steps decreases the success of implant. Inaccurate design of the implant increases the occlusal loading on the implants resulting in implant failure. Russell A. Wick in 1994 reported that thoughtful design selection is crucial for the perpetual success of any dental implant restoration.[26] Hence, laboratory technician also plays a significant role.[9]

Personnel responsible (late failures)

After successfully placing the implant, it is the patient's duty to take care of its maintenance in the oral cavity. Inadequate postoperative care, carelessness in maintaining oral hygiene leads to infection in the implant site causing peri-implantitis.[27] More bone resorption was noted around fixtures in edentulous patients with poor oral hygiene than in participants with good hygiene (Lindquist et al. 1988).[28] This proves that in addition to surgical precision, personnel involved in its procedure and maintenance are responsible for the fate of implant.[3]

Failure mode

The mode in which failure is caused is different in early and delayed failures. In early failures, it is due to lack of osseointegration, whereas in late failures, it is due to functional and psychological attributes of the patient.[3] Osseointegration is direct communication between implant surface and bone.[29],[30],[31],[32] Lack of osseointegration causes loosening of implant in the bone which decreases the success rate of implant.[3] Failure rates are high due to fibrous union of tissues instead of osseointegration.[30] Mobility of implants due to lack of osseointegration results in implant failure.[31],[32] Infection of implant site, poor bone quality, and improper design of the implant interfere in osseointegration process. Unacceptable esthetics, psychological problems such as emotional instability, emotional disturbances, dementia, and lack of support affect implant success.[3] Failure of implants is also caused by infections in the oral cavity. These mostly include peri-implantitis in early stages that is during or immediately after implant placement. In late stages, retrograde infection is the primary causative agent. These infections are broadly grouped into biological causes.[8] Peri-implantitis is an inflammatory process which affects the tissues around an osseointegrated implant.[3],[13],[27],[32] It results in loss of supporting bone along with bleeding, suppuration, increased probing depth, and mobility. Bacterial infection is the prime reason for peri-implantitis.[3],[13],[27],[32] Bacterial flora at failing implant site consists of Gram-negative anaerobic bacteria including Porphyromonas gingivalis, Prevotella intermedia, and Actinobacillus.[7],[27],[32] Studies by Mombelli et al. (1987)[33] and Rosenberg et al. (1991)[34] showed the presence of periodontal microorganisms around failing implants.[13] Retrograde peri-implantitis is also known as apical peri-implantitis or periapical implant lesion, occurring in the later stage of implant placement.[3],[7] It develops shortly after implant insertion while coronal portion of implant achieves a normal implant bone interface. However, very few failures have been reported due to retrograde infection.[3],[9]

   Conclusion Top

Failure of implant is a multifactorial occurrence. A combination of causes leads to ultimate failure of implant. Every dentist needs to identify the cause to treat the present condition. Proper data collection, patient feedback, and accurate diagnostic tools will help point out the reason for failure. An early intervention is always possible if regular checkups are undertaken. The treatment strategy for complications and failing implants is influenced by the identification of the possible etiologic factors. When a diagnosis is established and possible etiologic factors identified, the causative agent should be eliminated and treatment attempted as soon as possible.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Nallaswamy DV, Ramalingam K, Bhat V. Implant dentistry. In: Textbook of Prosthodontics. 1st ed. New Delhi: Jaypee Brothers Medical Publications; 2003. p. 736-38.  Back to cited text no. 1
Hasan MM. Review on dental implants: Success and failure. Bangladesh J Dent Res Educ 2012;2:22-3.  Back to cited text no. 2
Yeshwante B, Patil S, Baig N, Gaikwad S, Swami A, et al. Dental implants-classification, success and failure-overeview article. IOSR J f Dent Med Sci 2015;14:1-8.  Back to cited text no. 3
Razmara F, Kazemian M. Etiology, complications, key systemic and environmental risk factors in dental implant failure. Int J Contemp Dent Med Rev 2015;81:1-6.  Back to cited text no. 4
Prashanti E, Sajjan S, Reddy JM. Failure in implants. Indian J Dent Res 2011;2:446-53.  Back to cited text no. 5
[PUBMED]  [Full text]  
Esposito M, Hirsch JM, Lekholm U, Thomsen P. Biological factors contributingto failures of osseointegratedoral implants.(I) Success criteria and epidemiology. Eur J Oral Sci 1998;106: 527-51.  Back to cited text no. 6
Khatri J, Tated G. Failure in implantology-review article. J Appl Dent Med Sci 2015;1:55-62.  Back to cited text no. 7
Costa GC, Aras M, Chitre V. Failure in dental implants. Adv Dentl Med Sci 2014;2:68-81.  Back to cited text no. 8
Eswaran MA, Bettie NF, Rai R, Eswaran B, Thillaigovindan R. Failures in endosseous implants – A literature review. Int J Biomed Res 2015;6:756-62.  Back to cited text no. 9
Bahat O. “Treatment planning and placement of implants in posterior maxilla. Report of 732 consecutive Nobelpharma implants.” IJOMI 1993;8:151-61.  Back to cited text no. 10
Bahat O, Handelsman M. Use of wide implants and double implants in the posterior jaw: A clinical report. Int J Oral Maxillofac Implants 1996;11:379-86  Back to cited text no. 11
Chrcanovic BR, Albrektsson T, Wennerberg A. Reasons for failures of oral implants. J Oral Rehabil 2014;41:443-76.  Back to cited text no. 12
Hadi SA, Ashfaq N, Bey A, Khan S. Biological factors responsible for failure of osseointegration in oral implants. Biol Med 2011;3:164-70.  Back to cited text no. 13
Jaffin RA, Berman CL. The excessive loss of Branemark fixtures in type IV bone: A 5-year analysis. J Periodontol 1991;62:2-4.  Back to cited text no. 14
Atilla S, Guvener S. Finite element analysis of the effect of cantilever and implant length on stress distribution in an implant-supported fixed prosthesis. J Prosthet Dent 1996;76:165-9.  Back to cited text no. 15
Salonen MA, Oikarinen K, Virtanen K, Pernu H. Failures in the osseointegration of endosseous implants. Int J Oral Maxillofac Implants 1993 8:92-7.  Back to cited text no. 16
Watanabe F, Hata Y. Retrieval and replacement of a malpositioned dental implant: A clinical report. J Prosthet Dent 2002:88:255-8.  Back to cited text no. 17
Robert L. Simon; Single implant supported molar and premolar crowns: A ten-year retrospective clinical report. J Prosthet Dent 2003;90:517-21.  Back to cited text no. 18
Fiorellini JP, Chen PK, Nevins M, Nevins ML. A retrospective study of dental implants in diabetic patients. Int J Periodontics Restorative Dent 2000;20:366-73  Back to cited text no. 19
Olson JW, Shernoff AF, Tarlow JL, Colwell JA, Scheetz JP, Bingham SF,. Dental endosseous implant assessments in a type 2 diabetic population: a prospective study. Int J Oral Maxillofac Implants 2000;15:811-8.  Back to cited text no. 20
Keller JC, Stewart M, Roehm M. Osteoporosis-like Bone conditions affect osseointegration of implants. Int J Oral Maxillofac implants 2004;19:687-694.  Back to cited text no. 21
Moy PK, Medina D, Shetty V, Aghaloo TL. Dental implant failure rates and associated risk factors. Int J Oral Maxillofac Implants 2005;20:569-77.  Back to cited text no. 22
Twito D, Sade P. The effect of cigarette smoking habits on the outcome of dental implant treatment. PeerJ 2014 2;2:e546.  Back to cited text no. 23
Glauser R, Ree A, Lundgren A, Gottlow J, Hammerle CH, Scharer P. Immediate occlusal loading of Br_anemarkimplants applied in various jawbone regions: A prospective,1-year clinical study. Clin Implant Dent Relat Res 2001;3:204-13.  Back to cited text no. 24
Jacobsson M, Tjellstrom A, Thomsen P, Albrektsson T, Turesson I. Integration of titanium implants in irradiated bone. Histologic and clinical study. Ann Otol Rhinol Laryngol Suppl 1988;97:377-40.  Back to cited text no. 25
Russell A, Wicks MS. A systematic approach to definitive planning for osseointegrated implant prostheses. J Prosthod 1994;3:237-42.  Back to cited text no. 26
Gupta HK, Garg A, Bedi NK. Peri-implantitis: A risk factor in implant failure. J Clin Diagn Res 2011;5:138-41.  Back to cited text no. 27
Lindquist LW, Rockler B. Bone resorption around fixtures in edentulous patients treated with mandibular fixed tissue- integrated prostheses. J Prosthetic Dent 1988;59:59-63.  Back to cited text no. 28
Esposito M, Hirsch J, Lekholm U, Thomsen P. Differential diagnosis and treatment strategies for biological complications and failing oral implants. Int J Oral Maxillofac Implants 1999;14:473-90.  Back to cited text no. 29
Albrektsson T, Zarb G, Worthington P, Eriksson A R. Long term efficacy of currently used dental implant. Int J Oral Maxillofac Implants 1986;1:1-34.  Back to cited text no. 30
Sakka S, Coulthard P. Implant failure:Etiology and Complications, Med Oral Patol Oral Cir Bucal 2011;16:e42-4.  Back to cited text no. 31
Pye AD, Lockhart DEA, Dawson MP, Murray CA, Smith AJ. A review of dental implants and infection. J Hosp Infect 2009;72:104-10.  Back to cited text no. 32
Mombelli A, van Oosten MA, Schurch E, Land N. The microbiota associated with successful or failing osseointegrated titanium implants. J Oral Microbiol Immunol 1987 2:145-51.  Back to cited text no. 33
Rosenberg ES, Torosian JP, Slots J. Microbial differences in 2 clinically distinct types of failures of osseointegrated implants. Clin Oral Implants Res 1991;2:135-44.  Back to cited text no. 34


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]

  [Table 1]

This article has been cited by
1 Effect of plasma-nitrided titanium on mechanical properties and initial cell adhesion
Annop Krasaesin, Suruk Udonsom, Phornsawat Baipaywad, Kanokwan Sriwattanapong, Norased Nasongkla, Thantrira Porntaveetus, Thanaphum Osathanon, Shuichi Watanabe, Chavin Jongwannasiri, Chawan Manaspon
Materials Today: Proceedings. 2023;
[Pubmed] | [DOI]
2 Human umbilical cord mesenchymal stem cells induction in peri-implantitis rats accelerate and enhance osteogenesis activity and implant osseointegration
Nike Hendrijantini, Mefina Kuntjoro, Bambang Agustono, Ratri Maya Sitalaksmi, Muhammad Dimas Aditya Ari, Marcella Theodora, Rudy Effendi, Ivan Setiawan Djuarsa, Jennifer Widjaja, Agung Sosiawan, Guang Hong
The Saudi Dental Journal. 2023;
[Pubmed] | [DOI]
3 Editorial for the Special Issue on “Multidisciplinary Insights on Bone Healing”
Alexandre Anesi, Francesco Cavani
Biology. 2022; 11(12): 1776
[Pubmed] | [DOI]
4 The Stages and Grades of Periodontitis Are Risk Indicators for Peri-Implant Diseases—A Long-Term Retrospective Study
Mikiko Yamazaki, Kosaku Yamazaki, Yuh Baba, Hiroshi Ito, Bruno G. Loos, Keiso Takahashi
Journal of Personalized Medicine. 2022; 12(10): 1723
[Pubmed] | [DOI]
5 Dis Hekimliginde Biyoaktif Camlarin Kullanimi
ADO Klinik Bilimler Dergisi. 2022;
[Pubmed] | [DOI]
6 Peri-Implant bone response around porous-surface dental implants: A preclinical meta-analysis
Abeer Ahmed, Abdulaziz Al-Rasheed, Mohammed Badwelan, Hamdan S Alghamdi
The Saudi Dental Journal. 2021; 33(5): 239
[Pubmed] | [DOI]
7 Machining-induced thermal damage in cortical bone: Necrosis and micro-mechanical integrity
Jose A. Robles-Linares, Dragos Axinte, Zhirong Liao, Andres Gameros
Materials & Design. 2021; 197: 109215
[Pubmed] | [DOI]
8 A review article on factors affecting bone loss in dental implants
Shriya Nimbalkar, Pankaj Dhatrak, Chinmay Gherde, Srujana Joshi
Materials Today: Proceedings. 2021; 43: 970
[Pubmed] | [DOI]
9 Immunological Aspects of Dental Implant Rejection
Milad Baseri, Faraz Radmand, Reyhaneh Hamedi, Mehdi Yousefi, Hossein Samadi Kafil, Jun Lu
BioMed Research International. 2020; 2020: 1
[Pubmed] | [DOI]
10 Biomimetic in vitro test system for evaluation of dental implant materials
Franziska Ehlicke, Jonathan Berndt, Nina Marichikj, Doris Steinmüller-Nethl, Heike Walles, Ernst-Ulrich Berndt, Jan Hansmann
Dental Materials. 2020; 36(8): 1059
[Pubmed] | [DOI]
Suhana Shamsuddeen, Vino Kurien
Journal of Indian Dental Association. 2020;
[Pubmed] | [DOI]
12 Accuracy of Dynamic Navigation System Workflow for Implant Supported Full Arch Prosthesis: A Case Series
Luigi V. Stefanelli, George A. Mandelaris, Alessio Franchina, Nicola Pranno, Michele Pagliarulo, Francesca Cera, Fabio Maltese, Francesca De Angelis, Stefano Di Carlo
International Journal of Environmental Research and Public Health. 2020; 17(14): 5038
[Pubmed] | [DOI]
13 Removal of Dental Implants using Electrocautery: A Preliminary Report
Se-Jin Park, Sang-Hoon Kang
The Korean Academy of Oral and Maxillofacial Implantology. 2019; 23(4): 196
[Pubmed] | [DOI]


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

  In this article
   Review of Literature
    Article Figures
    Article Tables

 Article Access Statistics
    PDF Downloaded4986    
    Comments [Add]    
    Cited by others 13    

Recommend this journal