A bibliometric analysis of the studies on dental implant failure

Objective: To identify top 30 studies related to dental implant failures based on bibliometric analysis. Methods: The bibliometric study was conducted at Aga Khan University, Karachi from April 2021 to June 2021 and comprised database search on Google Scholar used key words "dental implant failures" for studies published between 1990 and 2020. The selected studies were reviewed based on citation count for which the cut-off date was June 1, 2021. Results: The top 30 papers on dental implant failures had median citation count of 153 (range: 41-1583. Most of the studies were retrospective 11(36.7%), followed by literature reviews 6(20%). The top three contributing journals were the 'International Journal of Oral Maxillofacial Implants' 6(20%), the 'Clinical Oral Implants Research' 5(16.7%) and 'Clinical Implant Dentistry and Related Research' 3(10%). Goteborg University, Sweden, contributed the maximum number of most cited papers 8(26.7%). Conclusions: Most of the papers in the top-cited on dental implant failures were retrospective studies, and there was only one clinical trial.


Introduction
Healthcare professionals update themselves with the current scientific literature using electronic media, conferences, textbooks and peer-reviewed journals. 1The published scientific literature is growing exponentially and it is estimated that the volume of literature in health sciences doubles every 7 years. 2This places the clinicians and researchers in a challenging situation of keeping abreast with the recent knowledge and practices. 3,4ibliometric analysis helps the reader to recognise the most acknowledged articles on the topics of interest. 5It gives a snapshot of the must-read articles on the given topic.Different parameters are evaluated in the bibliometric analysis, including the citation analysis, which is a simple measure of counting the number of times a particular paper has been cited by other publications. 6It is a commonly evaluated parameter in bibliometrics.Papers which are recognised to have significant bearing on a discipline get acknowledged more than the other papers with less impact. 7ibliometric analysis identifies variables such as country, institutions, authors and journals contributing to the discipline of interest. 8,9All of this helps the researchers in designing further studies and thus contributing to the scientific enquiry. 10,11th abundant literature already present in various specialties of Medicine, Dentistry, Nursing and Allied Health Sciences, an inquisitive mind might ask the question as to what makes an article a 'classic article'.The definition varies, but a citation count (CC) >400 is usually considered the cut-off. 12In certain specialties, due to limited volume of literature, CC >100 may be considered classic. 13However, Giatsidis et al. suggested that rather than the CC, the citation density (CD) should be considered the valid parameter in evaluating the impact of an article. 14e current study was planned to identify top 30 studies related to dental implant failures based on bibliometric analysis which could be helpful in formulating the syllabus for short-listing the papers that can be recommended as a must-read or suggested-read in the residency programmes, seminars and journal clubs related to residency/fellowship training programmes in Prosthodontics, Oral Surgery or Implant Dentistry Implantology.

Materials and Methods
The bibliometric study was conducted at Aga Khan University, Karachi from April 2021 to June 2021 and comprised database search on Google Scholar used key words "dental implant failures" for studies published between 1990 and 2020.The citation analysis was carried out on June 1, 2021.Only English-language papers were considered, and there were no exclusions made based on study design.There were 18,900 hits on that search.

Discussion
Dental implants have been popularised by Dr Branemark, a Swedish orthopaedic surgeon and scientist. 15He revolutionised the field of Dental Implantology with the introduction of titanium-based endosseous dental implants and the discovery of the phenomenon of osseointegration.Dental implant has become a popular method of replacing teeth worldwide.To date, millions of people have benefitted from dental implants.However, despite high predictability in the outcome of implants, a small but important subset of patients do experience failure. 16,17Subjects with osteoporosis, low bone volume, poor quality of bone, presence of metabolic bone disease, use of bisphosphonates and history of progressive periodontal disease etc. are at a greater risk of implant failure.[20] Implant failures are categorised as early and late failures. 21arly implant failures are caused by poor bone quality, medically compromised patients, like those with uncontrolled diabetes, inadequate surgical technique, chronic drug or alcohol consumption, and smoking status, whereas late causes of failures are occlusal overload/excessive stress, peri-implantitis and poor oral hygiene, and defective implant components. 17,22,23The most common reasons for late or delayed implant failure include implant overloading or fracture, and/or periimplantitis. 22bliometric analysis can serve as a useful tool for clinicians and researchers to appraise published literature on a given topic. 7The current study was carried out to identify the papers on dental implant failures that have the maximum impact on the knowledge and understanding of this topic.Ten out of the 30 top-cited papers on dental implant failures were from Sweden.This shows that Swedish researchers are at the forefront of research on dental implant and its failures.
Most of the papers in the top-cited list were retrospective studies and audits.It is logistically easier to carry out and publish retrospective studies as mostly there are no issues of funding associated with them.Moreover, the sample size or number of observations are usually higher, resulting in comparatively easier publication.In the present report, 11 of the 30 studies had retrospective study design.The importance of systematic reviews and meta-analysis cannot be underestimated, as they synthesise data from primary studies to yield the highest level of evidence that forms the basis of the evidencebased practice (EBP). 24,25In the present report, there were 4 systematic reviews/meta-analyses.Two of them were conducted at Wuhan University, China.
Literature reviews and narrative reviews do not provide a high level of evidence, and they have inherent biases.Despite increasing emphasis on evidence-based dentistry (EBD), it is worrying to observe that in the present list, 6 articles were literature reviews.The lack of randomised controlled trial (RCTs) in the list is a matter of concern.Ideally, owing to the level of evidence generated, the clinical trials should be cited more than the retrospective studies.
The limitation of the current study is that it has listed the paper based on CC which actually reflects the popularity of a paper rather than its true clinical significance and the impact on practice.Moreover, starting the literature search from 1990 was an arbitrary starting point, mainly to cater to electronically published papers as prior to 1990, several journals had print-only editions.Some important papers published before the cut-off point could have made it to the top cited list but were left unattended.Lastly, non-English literature was ignored, making citations from non-English literature, especially from Chinese, South Korean or Brazilian publications, excluded.

Table - 2
: List of top authors, journals, institutions and countries contributing to the most cited papers on dental implants failure.

authors Article serial # (as shown in table 1) Count*
*Only top 3-5 articles are reported, and, therefore, the numbers do not necessarily sum up to 30.