Relationship between Helicobacter pylori and Periodontal Diseases: A Meta-Analysis Study and Systematic Review

2.1. Protocol and Registration

The protocol of this research registers at the Ilam University of Medical Sciences, Ilam, Iran, in the Persian language with code 968051/137.

This review was conducted based on PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines [8].

2.2. Eligibility Criteria

To identify related studies, a systematic review of cross-sectional and case-control studies about the periodontal disease was performed.

To avoid bias, all steps of the study, including search, selection of studies, quality assessment, and data extraction, were conducted by two researchers independently. Any disagreement was reviewed by a third researcher.

2.3. Information Sources

To obtain related documents in English, scientific databases such as Scopus, PubMed, Science Direct, Web of Science, Springer, and Google Scholar were searched.

English MeSH keywords were used. Helicobacter pylori, tooth decay, oral infection, gingival infection, periodontal disease and also word combination of and/or operators were used as keywords.

2.4. Search

We used the following search terms to search all databases. As mentioned above, keywords including Helicobacter pylori, tooth decay, oral infection, gingival infection and periodontal disease and also word combination of and/or operators were used as keywords.

2.5. Study Selection

In the initial search, 125 studies probably related to periodontal diseases were selected. Seventy studies were excluded because they were duplicate papers (papers extracted by two researchers with identical titles, authors, and journal). From the remaining 55 studies, 29 cases were excluded after reading the summary and the full text due to non-relevance of the topic, and the lack of criteria and low quality. Of the remaining 26 studies, 16 cases were excluded. Finally, 10 studies were reviewed (Fig. 1).

Their data could be extracted and studies whose data could not be extracted (for various reasons such as they were duplicate papers (papers extracted by two researchers with identical titles, authors, and journal), some cases were excluded after reading the summary and the full text due to non-relevance of the topic, and the lack of criteria and low quality, etc.) were removed from the study.

2.6. Data Collection Process

In this study, a checklist of available studies was prepared. One author extracted the data from included studies and the second author checked the extracted data. The disagreement between them was solved by the third author and the final decision was the third author.

The review author agreed on the results of data extraction. The strategy used for study selection is displayed in Fig. (1). Ten studies published were eligible for meta-analysis (Table 1).

2.7. Data Items

All final papers imported to the study process were extracted by a pre-prepared checklist. The checklist includes the author's name, year of study, place of study, P-value, age, and Odds ratio and other data (Table 1).

2.8. Risk of Bias in Individual Studies

Researchers using a STROBE standard checklist [9] include 22 items. The selected studies were appraised in all aspects of methodology, including sampling methods, measurement parameters, statistical analysis and objectives of the study. The minimum and maximum scores in this checklist were 16 and 44, respectively. The papers that reached at least the minimum score were selected for the meta-analysis stage.

2.9. Summary Measures

The results of studies were combined based on the sample size, OR and its standard deviation.

2.10. Synthesis of Results

To assess the heterogeneity of the studies, the Cochran test and the I² (heterogeneity index) were used. Due to the significant heterogeneity in the studies, random effects model was used.

2.11. Risk of Bias Across Studies

The findings are described in forest plots (the point estimations and their 95% CI). To examine publication bias, the Begg plot and regressions method were used.

2.12. Additional Analyses

P-value less than 5% was considered as a significant heterogeneity test. Sensitivity analyses were pre-specified. Statistical analyses were performed using STATA version 11.

3.1. Study Selection

In the initial search, 125 studies probably related to periodontal diseases were selected. Some studies were excluded because they were duplicate papers. From the remaining studies, some cases were excluded after reading the summary and the full text due to non-relevance of the topic, and the lack of criteria and low quality. Finally, 10 studies were reviewed (Fig. 1).

3.2. Study Characteristics

Inclusion criteria including related papers about periodontal diseases in the English language were considered as inclusion criteria. Exclusion criteria including studies with non-randomly selected sample size, lack of relevance to the topic, letters to the editor, and case report studies were excluded.

3.3. Risk of Bias within Studies

The selected studies were appraised in all aspects of methodology, including sampling methods, measurement parameters, statistical analysis and objectives of the study. The papers that reached at least the minimum score were selected for the meta-analysis stage (This item is described in methods).

3.4. Results of Studies

In a systematic review of studies, 10 case-control and cross-sectional studies with 56,334 individuals fulfilled the inclusion criteria for the meta-analysis (Fig. 1). Oral and dental problems include patients with periodontitis diseases, dental calculus, loose tooth, recurrent aphthous stomatitis, etc.

In this regard, various studies were used, taking into account various parameters of oral diseases, the information of which could also be extracted.

Various parameters include: Dental calculus, Loose tooth, periodontal pocket depth, plaque index, gingival index, periodontal diseases, clinical attachment loss, oral sub mucous fibrosis, S: silivea, Dental biofilm Dental biofilm, Halitosis, Oral cancer

Note: Studies were conducted in which the information could be extracted.

3.5. Synthesis of Results

In the present study, a statistically significant difference was found between H. pylori and periodontal diseases; 1.13 (95% CI: 1.04 to 1.24). In other words, on analyzing the results of the present study, a strong association was found between the H. pylori and periodontal diseases (Fig. 2).

3.6. Risk of Bias Across Studies

According to publication linear form figure, in this diagram, the impact of the first study on other studies will be examined. In this study, by deleting the first study, its impressive impact will be on the overall results (Fig. 3).

In this study, we used different periodontal parameters such as Periodontal Pocket Depth (PPD), the Plaque Index (PI), the Gingival Index (GI), and Clinical Attachment Loss (CAL). In other words, we have various periodontal parameters extracted from a study and we consider them as one parameter as periodontal disease parameters. Eventually, we extracted a variety of data from one study, each of which was related to one of the periodontal diseases, but all of them considered as periodontal diseases (Table 1).

3.7. Additional Result

In this study, quality assessment was also performed. Quality scores were performed for every ten studies (Table 2).

4.1. Summary of Evidence

It is widely accepted that one of the causes of periodontal diseases is polymicrobial in nature [10]. Periodontal disease comprises a group of inflammatory diseases of the supporting structures of teeth that occur in a susceptible group of individuals. However, the beginning and the progress of periodontal diseases are impressed by the interaction of myriad genetics, environmental, host, and microbial factors [11]. Accordingly, there are many factors as a risk factor for the host that can create an infection or oral and tooth problems for the host, such as: socioeconomic status, race and geographic region. Therefore, it has been suggested that microbial testing is used to diagnose and optimize periodontal therapy and assess its outcome [12].

Although bacteria can also arguably be an important factor and also responsible for a wide range of systemic infections as well as local infection [13].